iThermonitor: A Wearable Non-Invasive High-Precision Alternative to Traditional Temperature Monitoring in Thoracoscopic Surgery of Lateral Decubitus Position

iThermonitor: A Wearable Non-Invasive High-Precision Alternative to Traditional Temperature Monitoring in Thoracoscopic Surgery of Lateral Decubitus Position | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article iThermonitor: A Wearable Non-Invasive High-Precision Alternative to Traditional Temperature Monitoring in Thoracoscopic Surgery of Lateral Decubitus Position Yanhong Yan, Jiao Geng, Xu Cui, Zhihai Ju, Guyan Wang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6685457/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract Purpose: In thoracoscopic surgery, temperature monitoring is essential but traditionally relies on invasive methods such as esophageal or rectal thermometry, which can lead to local mucosal damage and patient discomfort. This clinical trial evaluates the iThermonitor, a non-invasive, wireless, wearable axillary temperature monitoring device, as a potential alternative to traditional invasive methods, aiming to enhance patient preference and comfort by offering a non-invasive option that minimizes procedural discomfort while maintaining clinical precision. Patients and methods: We enrolled 80 adult patients scheduled for thoracoscopic surgery under general anesthesia between December 1, 2023, to May 31, 2024. The iThermonitor was used to measure axillary temperature, while lower esophageal temperature served as the reference standard. Temperature readings were recorded every 3 minutes. The primary outcome was the accuracy of the iThermonitor compared to lower esophageal temperature. Results: Analysis of 3536 temperature pairs showed the iThermonitor demonstrated high accuracy, with 93.96% of readings within ±0.5°C of the esophageal probe (95% CI: 91.94%–95.85%). The Pearson correlation coefficient was 0.75 ( P 1.5°C). The device showed strong predictive value for hypothermia (<36.0°C) with an AUC of 0.876. Notably, the esophageal probe exhibited bloodstaining in 73.8% of cases, whereas the iThermonitor caused only transient skin redness in 45% of patients, resolving completely postoperatively. Conclusion: The iThermonitor is a reliable and accurate non-invasive alternative to traditional invasive temperature monitoring methods in thoracoscopic surgery. It effectively detects perioperative hypothermia and offers significant patient-centered benefits, including enhanced comfort and safety. These findings support the potential of the iThermonitor to improve patient preference and adherence in clinical practice. Non-invasive monitoring Patient preference Patient comfort Accuracy Hypothermia Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Perioperative hypothermia, defined as a core body temperature below 36°C, is a common complication in surgical patients, with reported incidences ranging from 6–90% across various surgical procedures. 1 – 4 This temperature aberration is associated with adverse outcomes, including increased surgical bleeding, postoperative chills, anastomotic leakage, and elevated hospitalization costs, underscoring the critical need for effective temperature management strategies. 5 – 7 In light of the serious complications associated with perioperative hypothermia, precise temperature monitoring emerges as a key component of effective thermoregulation strategies. Traditional invasive temperature monitoring methods, such as esophageal and rectal thermometry, are accurate but can cause patient discomfort and pose a risk of tissue injury, as highlighted in a recent review. 8 This has prompted the development of non-invasive alternatives that offer real-time temperature assessment with reduced risk. Yet, their clinical accuracy continues to be a subject of scrutiny among researchers. 9 – 14 The iThermonitor, a non-invasive wireless device designed for axillary temperature monitoring, employs a proprietary algorithm to estimate core body temperature by compensating for environmental and skin temperature variations. Initial studies have shown promising correlations between the iThermonitor and lower esophageal temperatures in adult non-thoracic and non-cardiac surgeries. 15 However, its performance in thoracoscopic surgery, which is characterized by unique temperature dynamics and a higher incidence of hypothermia compared to non-thoracic surgery, 16 , 17 has not been extensively explored. Moreover, the device's diagnostic accuracy in detecting perioperative hypothermia has not been comprehensively established, which is crucial for its clinical adoption. This observational study aims to assess the iThermonitor's accuracy against lower esophageal temperature measurements in patients undergoing thoracoscopic surgery of lateral decubitus position. We will also evaluate the device's safety and its predictive capacity for perioperative hypothermia, providing valuable insights into its potential role in enhancing temperature management strategies in clinical practice and improving patient comfort in clinical practice. Material and methods This prospective study was approved by the Ethics Committee of Beijing Tongren Hospital (TREC2023-KY111) and registered with the Chinese Clinical Trial Registry (ChiCTR2300078340). Written informed consent was obtained from all participants. We enrolled adult patients scheduled for elective thoracoscopic surgery in the lateral decubitus position under general anesthesia between from December 1, 2023, to May 31, 2024. Patients were excluded if they had a history of esophageal surgery, diverticulum, or varices, conditions that could complicate the placement of the esophageal probe. Additionally, patients with local skin infections or ulcerations at the potential axillary monitoring site, or those with severe allergies to materials used in the monitoring device, were excluded from the study. Protocol Upon arrival in the operating room, intravenous access was established. The operating room temperature was maintained between 22°C and 23°C. Routine monitoring included heart rate, blood pressure, pulse oxygen saturation, electrocardiograms, and bispectral index (BIS). Invasive arterial blood pressure monitoring was performed selectively. The Enhanced Recovery After Surgery (ERAS) guidelines for thoracic anesthesia were followed. Fluid management, warming strategies, and anesthetic regimens were determined by the anesthesiologist. Axillary temperature was monitored using the iThermonitor, a non-invasive wireless device manufactured by Raiing Medical (Boston, MA, USA). The probe was placed in a shaved axilla contralateral to the surgical site, and a low-adherence film was applied to minimize skin irritation. Patients were instructed to adduct their ipsilateral arm for 5 minutes after probe placement or until the temperature reading stabilized. Following this initial stabilization period, patients were allowed to move their arms freely. The iThermonitor recorded temperature data every 4 seconds and transmitted it wirelessly to a mobile app for continuous monitoring. After anesthesia induction, the ES-DG-09A esophageal probe (Zhuhai Aisheng Medical Technology Co., Ltd., Guangdong, China) was inserted using a video laryngoscope to ensure proper placement in the esophagus, while simultaneously observing whether the tip of the probe was bloodstained. The depth of insertion was calculated based on the patient's height using established anatomical formulas to ensure optimal probe tip placement. 18 Real-time esophageal temperature data were displayed on the CARESCAPE B850 monitor (GE Healthcare, Boston, MA, USA) and simultaneously recorded in the anesthesia record. At the end of surgery, both the esophageal and axillary temperature probes were promptly removed. Following removal, the esophageal temperature probe was again checked for bloodstaining to assess potential mucosal injury, and the axillary site was examined for any skin reactions such as redness, bruising, or ulceration. Demographic and procedural details were recorded, including age, height, weight, gender, American Society of Anesthesiologists (ASA) physical status, type of surgery, procedural steps, and duration. Intraoperative fluid management, including infusion volumes, types, and temperatures of fluids, was also documented. Temperatures were recorded at 3-minute intervals throughout the surgery. Patients underwent rigorous postoperative surveillance for 48 hours, with a focus on detecting adverse events at the axillary site and nasotracheal area. Surveillance at the axillary site centered on identifying erythema, bruising, blistering, ulceration, or patient-reported discomfort. For the nasotracheal area, evaluations included checking for bleeding, nasal irritation, or patient-reported sensations suggestive of esophageal burning, which could signal mucosal injury from the esophageal temperature probe. Data Analysis The primary objective was to assess the clinical accuracy of axillary temperature monitoring using the iThermonitor in comparison with the reference standard of lower esophageal temperature. A difference of ± 0.5°C was set as the clinical accuracy threshold, in line with typical diurnal body temperature fluctuations and to ensure patient safety. 19 To evaluate this, the Bootstrap method with 10,000 resamples was used. This method calculated the average proportion of temperature readings within the ± 0.5°C range and estimated the 95% confidence interval, offering a thorough assessment of the iThermonitor's accuracy. The agreement between axillary and lower esophageal temperatures was further evaluated using the Bland-Altman method, which calculated the bias and its 95% CI. Additionally, the concordance correlation coefficient (CCC) and Cohen's Kappa were computed to gauge the level of agreement between the two monitoring methods. The iThermonitor's reliability was assessed using the US FDA's Allowable Total Error (ATE) and Limits of Erroneous Results (LER) guidelines, with thresholds set at ± 0.5°C and ± 1.5°C, respectively, to determine the device's reliability in core body temperature measurement. The predictive accuracy for clinical hypothermia was evaluated via Receiver Operating Characteristic (ROC) curve analysis. The area under the ROC curve (AUC) measured the iThermonitor's ability to discriminate hypothermia, with statistical significance set at P < 0.05. Adverse events related to the iThermonitor and the esophageal temperature probe were documented and analyzed descriptively. This included monitoring for skin reactions at the axillary site and potential mucosal injuries from the esophageal probe, with a focus on the incidence and severity of these events. For statistical analysis, SPSS 17.0 (IBM Corp., Armonk, NY, USA), MedCalc 20.010 (MedCalc Software Ltd., Ostend, Belgium), and R 4.2.1 (The R Foundation for Statistical Computing, Vienna, Austria) were utilized. Sample Size Calculation Utilizing PASS 15.0 software and pilot data from thoracoscopic surgery, we determined the sample size for our study. With axillary and lower esophageal temperatures recorded every 3 minutes, each patient contributed an average of 41 data pairs. Aiming for a 95% statistical power and a significance level (α) of 0.05, we based our calculation on a Pearson correlation coefficient of 0.7509 (95% CI, 0.7402 to 0.7713), which was derived from the pilot data. The analysis revealed that 3273 data pairs were required for the desired power. Consequently, we enrolled a minimum of 80 patients, each providing at least 41 data pairs, to meet the study's statistical requirements. Results Demographic and Clinical Characteristics Our study cohort comprised 80 patients undergoing thoracoscopic surgery under general anesthesia. Detailed demographic and intraoperative data are presented in Table 1 . Each patient contributed an average of 44 pairs of temperature readings, resulting in a total of 3536 pairs for analysis. The mean age of the cohort was (53.4 ± 14.4) years, and the mean BMI was (24.67 ± 3.81) kg/m². The median temperature collection time was 131 minutes (IQR: 127–139 minutes). The cohort included 48 males (60%). Initial mean esophageal and axillary temperatures were (36.69 ± 0.30)°C and (36.38 ± 0.36)°C, respectively, while final mean temperatures were (36.16 ± 0.26)°C and (36.11 ± 0.32)°C, respectively (Table 1 ). Table 1 Patient Demographics and Intraoperative Data Variable Result Age (years) 53.4 ± 14.4 BMI (kg/m²) 24.67 ± 3.81 Gender (Male %) 48 (60%) ASA Classification (II/III) 38/42 Temperature Recording Time (min) 131 (127, 139) Operating Room Temperature (°C) 22.0 (22.0, 23.0) Axillary Temperature on Admission (°C) 36.38 ± 0.36 Initial Esophageal Temperature (°C) 36.69 ± 0.30 Esophageal Temperature at the End of Surgery (°C) 36.16 ± 0.26 Axillary Temperature at the End of Surgery (°C) 36.11 ± 0.32 Note: Data are expressed as mean ± standard deviation or median (P 25 -P 75 ) or number of cases (%); BMI: Body mass index; ASA: American Society of Anesthesiologists. Accuracy of iThermonitor Compared to Lower Esophageal Temperature The iThermonitor demonstrated high accuracy in measuring axillary temperature, with 93.96% of readings within ± 0.5°C of the esophageal probe readings (95% CI: 91.94–95.85%). The Bland-Altman analysis (Fig. 1 ) revealed a mean difference (Bias) of 0.16°C, with limits of agreement ranging from − 0.33°C to 0.64°C (95% CI). A strong correlation between the two temperature monitoring methods was indicated by a Pearson correlation coefficient of 0.75 (95% CI: 0.74–0.77; P < 0.0001). The concordance correlation coefficient (CCC) was 0.69 (95% CI: 0.67–0.70), and Cohen's Kappa was 0.463 ( P < 0.001), suggesting moderate agreement between axillary and lower esophageal temperature measurements (Table 2 ). Table 2 Agreement Between iThermonitor and Esophageal Temperature. Measure Result Bias (°C) ( \(\:\stackrel{-}{x}\) ± SD) 0.16 ± 0.25 Upper limit (95% CI) 0.64 (0.59 ~ 0.69) Lower limit (95% CI) -0.33 (-0.39~-0.28) Proportion within 95% (95% CI) 93.96% (91.94%~95.85%) Concordance Correlation Coefficient (95% CI) 0.69 (0.67 ~ 0.70) Note: Bias calculated as the difference between axillary temperature measured by iThermonitor and Lower esophageal temperature. ATE/LER Analysis Allowable Total Error (ATE) and Limits of Erroneous Results (LER) analysis demonstrated that 94.3% of data points fell within the ATE zone (± 0.5°C), 5.7% within the ATE-LER zone (> 0.5°C to 1.5°C), and none in the LER zone (> 1.5°C), underscoring the iThermonitor's reliability in clinical settings. Predictive Value for Hypothermia Receiver Operating Characteristic (ROC) curve analysis confirmed the iThermonitor's diagnostic value for hypothermia (< 36.0℃), with an area under the curve (AUC) of 0.876. The optimal threshold for predicting hypothermia was ≤ 35.988°C, yielding a sensitivity of 87.1% and specificity of 78.3% (Fig. 3.1 ). At a threshold of < 35.5°C, the iThermonitor demonstrated 100% sensitivity and 70.4% specificity for hypothermia prediction (Fig. 3.2 ). Safety Profile Notably, during the insertion and removal of the esophageal temperature probe, the tip of the probe was observed and recorded for any signs of bloodstaining. Bloodstaining was noted in 73.8% of cases (59/80), highlighting the potential risks and adverse events associated with invasive temperature monitoring methods. In contrast, skin redness was observed at the axillary monitoring site in 45% of patients (36/80), with follow-up on the day after surgery revealing complete resolution without blisters or ulcerations. These findings underscore the iThermonitor's favorable safety profile compared to invasive methods. Discussion The iThermonitor exhibits remarkable accuracy in axillary temperature measurement, with 93.96% of readings falling within the clinically acceptable range of ± 0.5℃. 19 and a mean discrepancy of 0.16°C compared to lower esophageal temperature. A strong correlation (Pearson r = 0.75, P < 0.0001) between axillary and lower esophageal temperatures further supports its reliability as a non-invasive alternative to traditional invasive methods. By eliminating risks linked to invasive probes while maintaining diagnostic precision, the iThermonitor offers a patient-friendly approach to perioperative temperature monitoring, particularly in thoracoscopic surgery performed in the lateral decubitus position. These findings underscore its potential to enhance patient comfort and adherence without compromising clinical accuracy. Clinical Implications of iThermonitor's Accuracy In our study, iThermonitor offers 93.96% of readings falling within the clinically acceptable range of ± 0.5℃ 19 aligning with Pei et al., 15 who reported a 91% agreement between iThermonitor and lower esophageal temperatures in abdominal surgery patients. This superior performance in thoracoscopic surgery may stem from meticulous adherence to comprehensive thermal management protocols, crucial for stable intraoperative temperature readings. 5 , 6 Additional studies in pediatric patients 5 , 6 and adult surgical wards 21 have also demonstrated the iThermonitor's reliability across diverse clinical settings. Importantly, the device's performance in thoracoscopic surgery supports its potential as a reliable non-invasive alternative to traditional invasive methods, while maintaining clinical precision, suggesting it could play a valuable role in perioperative temperature management, especially in procedures prioritizing patient comfort. Our study demonstrates a strong correlation (Pearson r = 0.75, P < 0.0001) between axillary temperature measurements using the iThermonitor and lower esophageal temperatures, indicating a close alignment that is valuable for clinical practice. However, the concordance correlation coefficient (CCC) of 0.69 suggests that while the iThermonitor reliably complements esophageal monitoring, it does not achieve absolute agreement and should not be considered a complete surrogate in thoracoscopic surgery. This moderate CCC value may be attributed to physiological variances in core-to-peripheral temperature gradients and procedural factors such as surgical positioning and environmental conditions, which can introduce variability in temperature readings. 22 , 23 These findings underscore the importance of considering device limitations in specific clinical contexts while leveraging its non-invasive advantages for patient comfort and safety. Reliability Assessment via ATE/LER Analysis Our analysis demonstrated that 94.3% of data points fell within the Allowable Total Error (ATE) zone of ± 0.5°C, with 5.7% within the ATE-LER zone and none exceeding the Limits of Erroneous Results (LER) zone of ± 1.5°C. These results highlight the iThermonitor’s exceptional clinical accuracy, aligning with FDA recommendations for ensuring clinically meaningful agreement. 10 This performance underscores the device’s reliability in thoracoscopic surgery, where minimizing invasive procedures is critical for enhancing patient comfort and safety. The iThermonitor’s adherence to these stringent error margins further supports its role as a viable non-invasive alternative to traditional methods, particularly in procedures prioritizing patient well-being. In our analysis of the ATE/LER plot, we identified five outliers where the discrepancy between axillary and esophageal temperatures exceeded 1.0°C. These outliers were traced back to a 42-year-old female patient with a BMI of 18.1 kg/m². whose initial axillary temperature recorded by the iThermonitor was 35.2°C and remained below 36.0°C throughout the procedure, while her esophageal temperature also stayed below 36.5°C. This observation suggests that factors such as low initial thermometer readings, female gender, and low BMI may contribute to increased discrepancies between the two measurement methods, consistent with a prior observational study that analyzed temperature readings from 526 adult patients in surgical wards. 21 These factors may be attributed to variations in physiological cycles and challenges in achieving a snug fit for the axillary probe in low-weight patients. 21 To address these discrepancies, future studies could investigate additional common factors contributing to these outliers and explore strategies to mitigate them, such as adjusted monitoring protocols or device modifications for specific patient demographics. This approach would enhance the accuracy and reliability of non-invasive temperature monitoring across diverse clinical settings. Hypothermia Prediction Capabilities Our evaluation of the iThermonitor using a ROC curve with a diagnostic threshold of < 36.0°C demonstrated an AUC of 87.6%, indicating excellent diagnostic efficacy and aligning with established criteria where an AUC of 0.8–0.9 reflects superior diagnostic value. 24 Additionally, we explored the diagnostic potential of a lower threshold for perioperative hypothermia. In line with the recent challenge by Sessler et al. 25 who suggested that a less aggressive warming target of 35.5°C may be as effective as the normothermic target of 37.0°C in preventing major cardiovascular and infectious complications, our results showed that the iThermonitor had a significant diagnostic value with an AUC of 88.0% at the 35.5°C threshold, with 100% sensitivity and 70.4% specificity ( P < 0.0001). These findings highlight the iThermonitor’s ability to accurately detect hypothermic events even at lower thresholds, potentially aiding in the development of targeted temperature maintenance strategies and reducing hypothermia-related adverse events. Patient-Centered Benefits and Comfort Invasive temperature monitoring methods, such as those involving the pulmonary artery, lower esophagus, nasopharynx, bladder, and rectum, are widely recognized for causing patient discomfort and posing a risk of local trauma. 26 The development of non-invasive monitoring devices, like the wireless iThermonitor, has addressed these concerns by offering a more patient-friendly alternative. A recent review reported a relatively low incidence of adverse device effects (ADEs) for non-invasive vital sign monitoring devices, with no serious adverse reactions noted, highlighting the safety profile of such devices. 27 These ADEs typically manifest as mild skin symptoms such as itching, redness, and allergies, which are reversible by simple measures like changing the probe site or temporarily removing the device. 21 In our study, we observed a 73.8% incidence of esophageal temperature probe bloodstaining, which may indicate localized mucosal injury. However, postoperative follow-ups on days two and three revealed no symptoms such as esophageal burning or hematemesis, suggesting that these minor injuries resolved without clinical consequence. Additionally, skin redness was observed at the axillary monitoring site in 45% of patients, which resolved within the second and third postoperative days without any blisters or ulcerations. Liu et al. 21 reported a 5% incidence of skin adverse reactions related to the iThermonitor. The higher incidence of skin reactions in our study may be attributed to the specific patient positioning required for thoracoscopic surgery, where the side-lying position and the need to place the probe away from the surgical field may result in local compression. Nevertheless, the iThermonitor demonstrated a favorable safety profile, with no serious skin reactions recorded, aligning with the mentioned safety standards of non-invasive monitoring devices. Limitations and Future Research Directions Our study has several limitations and future research directions that should be considered. First, the study focused on thoracoscopic surgery in the lateral decubitus position, which limits the generalizability of our findings to more invasive procedures, such as open-chest surgery. Second, our results may not apply to patients with extreme BMI values, highlighting the need for demographic-specific calibrations. Third, while the iThermonitor demonstrated high accuracy in this study, its performance in other clinical settings or patient populations requires further validation. Future research could address these limitations by incorporating more comprehensive evaluations, such as endoscopic examinations, to assess mucosal damage caused by invasive temperature monitoring methods. Additionally, exploring patient-centered outcomes, such as comfort and anxiety reduction, would provide valuable insights into the benefits of non-invasive monitoring technologies. Finally, refining the device or protocol to address skin sensitivity, particularly in the lateral decubitus position, could enhance patient safety and acceptance, improving the accuracy and reliability of non-invasive temperature monitoring across diverse clinical contexts. Conclusion The iThermonitor's high sensitivity and specificity in detecting hypothermia make it a valuable tool for preventing and managing perioperative hypothermia. Its non-invasive design not only enhances patient comfort but also aligns with efforts to minimize procedural discomfort and maximize patient well-being. The device's ability to accurately reflect core body temperature, combined with its favorable safety profile, positions it as a promising alternative to traditional invasive methods. Future studies focusing on patient-reported outcomes and performance across diverse clinical settings will further solidify its role in advancing patient-centered care and optimizing perioperative temperature management. Declarations Acknowledgments We thank XinXin Hao and Ying Liu for their assistance in data collection and follow-up. Funding This work was supported by the Beijing Hospitals Authority’s Ascent Plan [grant number DFL20220203]. The funding organization had no role in the study design, data collection, or the decision to publish the results. Author contributions Guyan Wang: This author was the lead designer of the study and supervised all study phases. Yanhong Yan: This author provided significant input into the statistical analyses, manuscript drafting, and revisions. Jiao Geng: This author provided significant input into the manuscript drafting, and revisions. Xu Cui: This author assisted in executing the study and made valuable revisions to the manuscript. Zhihai Ju: This author assisted in executing the study and made valuable revisions to the manuscript. Each author has affirmed their contribution to this manuscript and has given consent for its submission. Ethics approval The clinical trial number is ChiCTR2300078340, and it is registered with the Chinese Clinical Trial Registration website, which can be accessed at Chinese Clinical Trial Register (ChiCTR). Data availability statement The dataset supporting the findings of this study is available upon reasonable request to the corresponding author, [Guyan Wang], at [ [email protected] ]. Requests for access to the data will be reviewed by the corresponding author and data access may be granted, subject to any necessary approvals and agreements to protect the privacy and confidentiality of participants. Disclosure The authors report no conflicts of interest in this work. References Laupland KB, Zahar JR, Adrie C, et al. Severe hypothermia increases the risk for intensive care unit-acquired infection. Clin Infect Dis . 2012;54(8):1064-1070. doi:10.1093/cid/cir1033 Harper CM, Andrzejowski JC, Alexander R. NICE and warm. Br J Anaesth . 2008;101(3):293-295. doi:10.1093/bja/aen233 Boet S, Patey AM, Baron JS, et al. Factors that influence effective perioperative temperature management by anesthesiologists: a qualitative study using the Theoretical Domains Framework. 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Sessler DI, Pei L, Li K, et al. Aggressive intraoperative warming versus routine thermal management during non-cardiac surgery (PROTECT): a multicentre, parallel group, superiority trial. Lancet . 2022;399(10337):1799-1808. doi:10.1016/S0140-6736(22)00560-8 Sessler DI. Perioperative Temperature Monitoring. Anesthesiology . 2021;134(1):111-118. doi:10.1097/ALN.0000000000003481 Aagaard N, Larsen AT, Aasvang EK, Meyhoff CS. The impact of continuous wireless monitoring on adverse device effects in medical and surgical wards: a review of current evidence. J Clin Monit Comput . 2023;37(1):7-17. doi:10.1007/s10877-022-00899-x Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 22 Jun, 2025 Reviews received at journal 17 Jun, 2025 Reviewers agreed at journal 03 Jun, 2025 Reviewers invited by journal 02 Jun, 2025 Editor assigned by journal 18 May, 2025 Submission checks completed at journal 18 May, 2025 First submitted to journal 17 May, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6685457","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":466013401,"identity":"28fdb008-d723-4459-8d97-97400094c3a1","order_by":0,"name":"Yanhong Yan","email":"","orcid":"","institution":"Beijing Tongren Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yanhong","middleName":"","lastName":"Yan","suffix":""},{"id":466013402,"identity":"3343c0b7-552e-4081-aff7-7607db5e880a","order_by":1,"name":"Jiao Geng","email":"","orcid":"","institution":"National Cancer Center, Chinese Academy of Medical Sciences and Peking Union Medical College","correspondingAuthor":false,"prefix":"","firstName":"Jiao","middleName":"","lastName":"Geng","suffix":""},{"id":466013405,"identity":"2115ced9-565e-46a1-b9fb-1302e5a0cba5","order_by":2,"name":"Xu Cui","email":"","orcid":"","institution":"Beijing Tongren Hospital","correspondingAuthor":false,"prefix":"","firstName":"Xu","middleName":"","lastName":"Cui","suffix":""},{"id":466013408,"identity":"5f730e1c-ae75-40de-b162-1f112ba7f49e","order_by":3,"name":"Zhihai Ju","email":"","orcid":"","institution":"Beijing Tongren Hospital","correspondingAuthor":false,"prefix":"","firstName":"Zhihai","middleName":"","lastName":"Ju","suffix":""},{"id":466013409,"identity":"74141d6c-c1df-4b5f-b1fd-877685b30366","order_by":4,"name":"Guyan Wang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA9UlEQVRIiWNgGAWjYFAD9saGAx8qJOTkidfCc/jgwxlnLIwNG4jWIpGWbMzZVpHIcICAQvmIHMPPhW12efIOOWbSjPMkEhgbmB8+uoFHi+GNHGPpmW3JxYYHzphJF26TyGNnYDM2zsGnZUaOgTTvNubEjY09ZtIzt0kUMzbwsEkT0GL8m3dbfeLGZh4zad45EokNBwhokZcAeoF32+HE+Wxsyca8DURoMeB5VmbN++944gYeZmAgH5MwNmwm4Bf59uTNt3nOVCfOn/8QGJU1dXLy7M0PH+O15QCHAZQBE2LGoxxsSwP7AyiDgMpRMApGwSgYuQAAAlBOnxwpIy0AAAAASUVORK5CYII=","orcid":"","institution":"Beijing Tongren Hospital","correspondingAuthor":true,"prefix":"","firstName":"Guyan","middleName":"","lastName":"Wang","suffix":""}],"badges":[],"createdAt":"2025-05-17 08:08:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6685457/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6685457/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":84218960,"identity":"31b6ddaa-1627-4cc8-b564-c01481f1d111","added_by":"auto","created_at":"2025-06-09 11:20:42","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":147002,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBland-Altman analysis of lower esophageal temperature and iThermonitor temperature in all patients.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBland-Altman analysis comparing axillary (iThermonitor) and lower esophageal temperatures (LET). The mean of LET and axillary temperatures is plotted on the x-axis in °C, and the difference between LET and axillary temperatures is on the y-axis in °C. The blue solid line indicates the mean difference (0.16°C), the orange dashed lines represent the 95% limits of agreement (0.64, - 0.33) in °C, the pink dotted line represents the difference of 0 °C, the green solid line represents ±0.5 °C.\u003c/p\u003e","description":"","filename":"fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-6685457/v1/85bf8f11f52c553dadeb43df.png"},{"id":84218964,"identity":"3d9bd5f8-a555-4614-aaa8-0147e2fa3273","added_by":"auto","created_at":"2025-06-09 11:20:42","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":359986,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eATE/LER plot of iThermonitor compared with lower esophageal temperature\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFigure 2 presents an ATE/LER plot comparing lower esophageal temperature (LET) and axillary temperature measurements from the iThermonitor. The x-axis displays LET in °C, and the y-axis shows axillary temperatures recorded by iThermonitor in °C. The central black solid line represents the line of identity (y=x), indicating perfect agreement between the two measurement methods. The green area represents the Allowable Total Error (ATE) zone, reflecting a clinically acceptable error range of ±0.5°C. The yellow area denotes the transition zone between ATE and LER, where errors range from 0.5°C to 1.5°C. The purple area signifies the Limits for Erroneous Results (LER), where errors exceed 1.5°C and may potentially lead to incorrect clinical decisions.\u003c/p\u003e","description":"","filename":"fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-6685457/v1/65e269e751f448078dcd1809.png"},{"id":84218961,"identity":"9ca691b7-5952-4628-b114-112c71e9e3ac","added_by":"auto","created_at":"2025-06-09 11:20:42","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":74816,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eROC curve of iThermonitor predicting hypothermia (＜36.0℃)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 3.1: \u003c/strong\u003eReceiver Operating Characteristic (ROC) curve demonstrating the diagnostic performance of the iThermonitor in detecting hypothermia (\u0026lt;36.0℃). The x-axis represents 100-specificity (%), and the y-axis represents sensitivity (%). The Area Under the Curve (AUC) indicates the overall accuracy of the iThermonitor. The point ★ annotated on the ROC curve has a sensitivity of 87.1% and a specificity of 78.3% at a critical axillary temperature of ≤35.988℃, as determined by the Youden index.\u003c/p\u003e","description":"","filename":"fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-6685457/v1/440cf651e4a24210c881590e.png"},{"id":84218962,"identity":"32c74c26-9dc7-4b64-b768-7cd967ef52ab","added_by":"auto","created_at":"2025-06-09 11:20:42","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":80610,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eFigure 3.2 ROC curve of iThermonitor predicting hypothermia (＜35.5℃)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFigure 3.2: \u003c/strong\u003eReceiver Operating Characteristic (ROC) curve demonstrating the diagnostic efficacy of the iThermonitor in identifying hypothermia with a threshold of \u0026lt;35.5℃. The x-axis represents 100-specificity (%), and the y-axis indicates sensitivity (%). The Area Under the Curve (AUC) denotes the overall diagnostic capability. The point ★ on the curve, marked by the Youden Index, shows 100% sensitivity and 70.4% specificity at the critical axillary temperature of ≤35.922°C, as determined by the Youden index.\u003c/p\u003e","description":"","filename":"fig4.png","url":"https://assets-eu.researchsquare.com/files/rs-6685457/v1/0f8cef3503fce487976c18cf.png"},{"id":84220222,"identity":"c45731e4-3f9a-4c66-9a18-64902513283e","added_by":"auto","created_at":"2025-06-09 11:28:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1474795,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6685457/v1/86eeff0d-46df-4869-97f8-9b0693e9587c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"iThermonitor: A Wearable Non-Invasive High-Precision Alternative to Traditional Temperature Monitoring in Thoracoscopic Surgery of Lateral Decubitus Position","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePerioperative hypothermia, defined as a core body temperature below 36\u0026deg;C, is a common complication in surgical patients, with reported incidences ranging from 6\u0026ndash;90% across various surgical procedures.\u003csup\u003e\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e This temperature aberration is associated with adverse outcomes, including increased surgical bleeding, postoperative chills, anastomotic leakage, and elevated hospitalization costs, underscoring the critical need for effective temperature management strategies.\u003csup\u003e\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn light of the serious complications associated with perioperative hypothermia, precise temperature monitoring emerges as a key component of effective thermoregulation strategies. Traditional invasive temperature monitoring methods, such as esophageal and rectal thermometry, are accurate but can cause patient discomfort and pose a risk of tissue injury, as highlighted in a recent review. \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003eThis has prompted the development of non-invasive alternatives that offer real-time temperature assessment with reduced risk. Yet, their clinical accuracy continues to be a subject of scrutiny among researchers.\u003csup\u003e\u003cspan additionalcitationids=\"CR10 CR11 CR12 CR13\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThe iThermonitor, a non-invasive wireless device designed for axillary temperature monitoring, employs a proprietary algorithm to estimate core body temperature by compensating for environmental and skin temperature variations. Initial studies have shown promising correlations between the iThermonitor and lower esophageal temperatures in adult non-thoracic and non-cardiac surgeries.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e However, its performance in thoracoscopic surgery, which is characterized by unique temperature dynamics and a higher incidence of hypothermia compared to non-thoracic surgery,\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e,\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003ehas not been extensively explored. Moreover, the device's diagnostic accuracy in detecting perioperative hypothermia has not been comprehensively established, which is crucial for its clinical adoption.\u003c/p\u003e \u003cp\u003eThis observational study aims to assess the iThermonitor's accuracy against lower esophageal temperature measurements in patients undergoing thoracoscopic surgery of lateral decubitus position. We will also evaluate the device's safety and its predictive capacity for perioperative hypothermia, providing valuable insights into its potential role in enhancing temperature management strategies in clinical practice and improving patient comfort in clinical practice.\u003c/p\u003e"},{"header":"Material and methods","content":"\u003cp\u003e This prospective study was approved by the Ethics Committee of Beijing Tongren Hospital (TREC2023-KY111) and registered with the Chinese Clinical Trial Registry (ChiCTR2300078340). Written informed consent was obtained from all participants. We enrolled adult patients scheduled for elective thoracoscopic surgery in the lateral decubitus position under general anesthesia between from December 1, 2023, to May 31, 2024. Patients were excluded if they had a history of esophageal surgery, diverticulum, or varices, conditions that could complicate the placement of the esophageal probe. Additionally, patients with local skin infections or ulcerations at the potential axillary monitoring site, or those with severe allergies to materials used in the monitoring device, were excluded from the study.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eProtocol\u003c/h2\u003e \u003cp\u003eUpon arrival in the operating room, intravenous access was established. The operating room temperature was maintained between 22\u0026deg;C and 23\u0026deg;C. Routine monitoring included heart rate, blood pressure, pulse oxygen saturation, electrocardiograms, and bispectral index (BIS). Invasive arterial blood pressure monitoring was performed selectively. The Enhanced Recovery After Surgery (ERAS) guidelines for thoracic anesthesia were followed. Fluid management, warming strategies, and anesthetic regimens were determined by the anesthesiologist.\u003c/p\u003e \u003cp\u003eAxillary temperature was monitored using the iThermonitor, a non-invasive wireless device manufactured by Raiing Medical (Boston, MA, USA). The probe was placed in a shaved axilla contralateral to the surgical site, and a low-adherence film was applied to minimize skin irritation. Patients were instructed to adduct their ipsilateral arm for 5 minutes after probe placement or until the temperature reading stabilized. Following this initial stabilization period, patients were allowed to move their arms freely. The iThermonitor recorded temperature data every 4 seconds and transmitted it wirelessly to a mobile app for continuous monitoring.\u003c/p\u003e \u003cp\u003eAfter anesthesia induction, the ES-DG-09A esophageal probe (Zhuhai Aisheng Medical Technology Co., Ltd., Guangdong, China) was inserted using a video laryngoscope to ensure proper placement in the esophagus, while simultaneously observing whether the tip of the probe was bloodstained. The depth of insertion was calculated based on the patient's height using established anatomical formulas to ensure optimal probe tip placement. \u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e Real-time esophageal temperature data were displayed on the CARESCAPE B850 monitor (GE Healthcare, Boston, MA, USA) and simultaneously recorded in the anesthesia record. At the end of surgery, both the esophageal and axillary temperature probes were promptly removed. Following removal, the esophageal temperature probe was again checked for bloodstaining to assess potential mucosal injury, and the axillary site was examined for any skin reactions such as redness, bruising, or ulceration.\u003c/p\u003e \u003cp\u003eDemographic and procedural details were recorded, including age, height, weight, gender, American Society of Anesthesiologists (ASA) physical status, type of surgery, procedural steps, and duration. Intraoperative fluid management, including infusion volumes, types, and temperatures of fluids, was also documented. Temperatures were recorded at 3-minute intervals throughout the surgery.\u003c/p\u003e \u003cp\u003ePatients underwent rigorous postoperative surveillance for 48 hours, with a focus on detecting adverse events at the axillary site and nasotracheal area. Surveillance at the axillary site centered on identifying erythema, bruising, blistering, ulceration, or patient-reported discomfort. For the nasotracheal area, evaluations included checking for bleeding, nasal irritation, or patient-reported sensations suggestive of esophageal burning, which could signal mucosal injury from the esophageal temperature probe.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eData Analysis\u003c/h2\u003e \u003cp\u003eThe primary objective was to assess the clinical accuracy of axillary temperature monitoring using the iThermonitor in comparison with the reference standard of lower esophageal temperature. A difference of \u0026plusmn;\u0026thinsp;0.5\u0026deg;C was set as the clinical accuracy threshold, in line with typical diurnal body temperature fluctuations and to ensure patient safety.\u003csup\u003e\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e To evaluate this, the Bootstrap method with 10,000 resamples was used. This method calculated the average proportion of temperature readings within the \u0026plusmn;\u0026thinsp;0.5\u0026deg;C range and estimated the 95% confidence interval, offering a thorough assessment of the iThermonitor's accuracy.\u003c/p\u003e \u003cp\u003eThe agreement between axillary and lower esophageal temperatures was further evaluated using the Bland-Altman method, which calculated the bias and its 95% CI. Additionally, the concordance correlation coefficient (CCC) and Cohen's Kappa were computed to gauge the level of agreement between the two monitoring methods.\u003c/p\u003e \u003cp\u003e The iThermonitor's reliability was assessed using the US FDA's Allowable Total Error (ATE) and Limits of Erroneous Results (LER) guidelines, with thresholds set at \u0026plusmn;\u0026thinsp;0.5\u0026deg;C and \u0026plusmn;\u0026thinsp;1.5\u0026deg;C, respectively, to determine the device's reliability in core body temperature measurement.\u003c/p\u003e \u003cp\u003eThe predictive accuracy for clinical hypothermia was evaluated via Receiver Operating Characteristic (ROC) curve analysis. The area under the ROC curve (AUC) measured the iThermonitor's ability to discriminate hypothermia, with statistical significance set at \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003cp\u003eAdverse events related to the iThermonitor and the esophageal temperature probe were documented and analyzed descriptively. This included monitoring for skin reactions at the axillary site and potential mucosal injuries from the esophageal probe, with a focus on the incidence and severity of these events.\u003c/p\u003e \u003cp\u003eFor statistical analysis, SPSS 17.0 (IBM Corp., Armonk, NY, USA), MedCalc 20.010 (MedCalc Software Ltd., Ostend, Belgium), and R 4.2.1 (The R Foundation for Statistical Computing, Vienna, Austria) were utilized.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSample Size Calculation\u003c/h3\u003e\n\u003cp\u003eUtilizing PASS 15.0 software and pilot data from thoracoscopic surgery, we determined the sample size for our study. With axillary and lower esophageal temperatures recorded every 3 minutes, each patient contributed an average of 41 data pairs. Aiming for a 95% statistical power and a significance level (α) of 0.05, we based our calculation on a Pearson correlation coefficient of 0.7509 (95% CI, 0.7402 to 0.7713), which was derived from the pilot data. The analysis revealed that 3273 data pairs were required for the desired power. Consequently, we enrolled a minimum of 80 patients, each providing at least 41 data pairs, to meet the study's statistical requirements.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eDemographic and Clinical Characteristics\u003c/h2\u003e \u003cp\u003eOur study cohort comprised 80 patients undergoing thoracoscopic surgery under general anesthesia. Detailed demographic and intraoperative data are presented in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Each patient contributed an average of 44 pairs of temperature readings, resulting in a total of 3536 pairs for analysis. The mean age of the cohort was (53.4\u0026thinsp;\u0026plusmn;\u0026thinsp;14.4) years, and the mean BMI was (24.67\u0026thinsp;\u0026plusmn;\u0026thinsp;3.81) kg/m\u0026sup2;. The median temperature collection time was 131 minutes (IQR: 127\u0026ndash;139 minutes). The cohort included 48 males (60%). Initial mean esophageal and axillary temperatures were (36.69\u0026thinsp;\u0026plusmn;\u0026thinsp;0.30)\u0026deg;C and (36.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.36)\u0026deg;C, respectively, while final mean temperatures were (36.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.26)\u0026deg;C and (36.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.32)\u0026deg;C, respectively (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePatient Demographics and Intraoperative Data\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eResult\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53.4\u0026thinsp;\u0026plusmn;\u0026thinsp;14.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI (kg/m\u0026sup2;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24.67\u0026thinsp;\u0026plusmn;\u0026thinsp;3.81\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGender (Male %)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e48 (60%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eASA Classification (II/III)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38/42\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemperature Recording Time (min)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e131 (127, 139)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOperating Room Temperature (\u0026deg;C)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e22.0 (22.0, 23.0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAxillary Temperature on Admission (\u0026deg;C)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInitial Esophageal Temperature (\u0026deg;C)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36.69\u0026thinsp;\u0026plusmn;\u0026thinsp;0.30\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEsophageal Temperature at the End of Surgery (\u0026deg;C)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.26\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAxillary Temperature at the End of Surgery (\u0026deg;C)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e36.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003eNote: Data are expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation or median (P\u003csub\u003e25\u003c/sub\u003e -P\u003csub\u003e75\u003c/sub\u003e) or number of cases (%); BMI: Body mass index; ASA: American Society of Anesthesiologists.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eAccuracy of iThermonitor Compared to Lower Esophageal Temperature\u003c/h2\u003e \u003cp\u003eThe iThermonitor demonstrated high accuracy in measuring axillary temperature, with 93.96% of readings within \u0026plusmn;\u0026thinsp;0.5\u0026deg;C of the esophageal probe readings (95% CI: 91.94\u0026ndash;95.85%). The Bland-Altman analysis (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e) revealed a mean difference (Bias) of 0.16\u0026deg;C, with limits of agreement ranging from \u0026minus;\u0026thinsp;0.33\u0026deg;C to 0.64\u0026deg;C (95% CI). A strong correlation between the two temperature monitoring methods was indicated by a Pearson correlation coefficient of 0.75 (95% CI: 0.74\u0026ndash;0.77; \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). The concordance correlation coefficient (CCC) was 0.69 (95% CI: 0.67\u0026ndash;0.70), and Cohen's Kappa was 0.463 (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), suggesting moderate agreement between axillary and lower esophageal temperature measurements (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAgreement Between iThermonitor and Esophageal Temperature.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMeasure\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eResult\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBias (\u0026deg;C) (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\stackrel{-}{x}\\)\u003c/span\u003e\u003c/span\u003e \u0026plusmn; SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.16\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUpper limit (95% CI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.64 (0.59\u0026thinsp;~\u0026thinsp;0.69)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLower limit (95% CI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-0.33 (-0.39~-0.28)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProportion within 95% (95% CI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e93.96% (91.94%~95.85%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConcordance Correlation Coefficient (95% CI)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.69 (0.67\u0026thinsp;~\u0026thinsp;0.70)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e\u003cstrong\u003eNote:\u003c/strong\u003e Bias calculated as the difference between axillary temperature measured by iThermonitor and Lower esophageal temperature.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eATE/LER Analysis\u003c/h3\u003e\n\u003cp\u003eAllowable Total Error (ATE) and Limits of Erroneous Results (LER) analysis demonstrated that 94.3% of data points fell within the ATE zone (\u0026plusmn;\u0026thinsp;0.5\u0026deg;C), 5.7% within the ATE-LER zone (\u0026gt;\u0026thinsp;0.5\u0026deg;C to 1.5\u0026deg;C), and none in the LER zone (\u0026gt;\u0026thinsp;1.5\u0026deg;C), underscoring the iThermonitor's reliability in clinical settings.\u003c/p\u003e\n\u003ch3\u003ePredictive Value for Hypothermia\u003c/h3\u003e\n\u003cp\u003eReceiver Operating Characteristic (ROC) curve analysis confirmed the iThermonitor's diagnostic value for hypothermia (\u0026lt;\u0026thinsp;36.0℃), with an area under the curve (AUC) of 0.876. The optimal threshold for predicting hypothermia was \u0026le;\u0026thinsp;35.988\u0026deg;C, yielding a sensitivity of 87.1% and specificity of 78.3% (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e3.1\u003c/span\u003e). At a threshold of \u0026lt;\u0026thinsp;35.5\u0026deg;C, the iThermonitor demonstrated 100% sensitivity and 70.4% specificity for hypothermia prediction (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e3.2\u003c/span\u003e).\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eSafety Profile\u003c/h2\u003e \u003cp\u003eNotably, during the insertion and removal of the esophageal temperature probe, the tip of the probe was observed and recorded for any signs of bloodstaining. Bloodstaining was noted in 73.8% of cases (59/80), highlighting the potential risks and adverse events associated with invasive temperature monitoring methods. In contrast, skin redness was observed at the axillary monitoring site in 45% of patients (36/80), with follow-up on the day after surgery revealing complete resolution without blisters or ulcerations. These findings underscore the iThermonitor's favorable safety profile compared to invasive methods.\u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe iThermonitor exhibits remarkable accuracy in axillary temperature measurement, with 93.96% of readings falling within the clinically acceptable range of \u0026plusmn;\u0026thinsp;0.5℃.\u003csup\u003e19\u003c/sup\u003e and a mean discrepancy of 0.16\u0026deg;C compared to lower esophageal temperature. A strong correlation (Pearson r\u0026thinsp;=\u0026thinsp;0.75, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) between axillary and lower esophageal temperatures further supports its reliability as a non-invasive alternative to traditional invasive methods. By eliminating risks linked to invasive probes while maintaining diagnostic precision, the iThermonitor offers a patient-friendly approach to perioperative temperature monitoring, particularly in thoracoscopic surgery performed in the lateral decubitus position. These findings underscore its potential to enhance patient comfort and adherence without compromising clinical accuracy.\u003c/p\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eClinical Implications of iThermonitor's Accuracy\u003c/h2\u003e \u003cp\u003eIn our study, iThermonitor offers 93.96% of readings falling within the clinically acceptable range of \u0026plusmn;\u0026thinsp;0.5℃\u003csup\u003e19\u003c/sup\u003ealigning with Pei et al.,\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003ewho reported a 91% agreement between iThermonitor and lower esophageal temperatures in abdominal surgery patients. This superior performance in thoracoscopic surgery may stem from meticulous adherence to comprehensive thermal management protocols, crucial for stable intraoperative temperature readings.\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e Additional studies in pediatric patients\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e,\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e and adult surgical wards\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e have also demonstrated the iThermonitor's reliability across diverse clinical settings. Importantly, the device's performance in thoracoscopic surgery supports its potential as a reliable non-invasive alternative to traditional invasive methods, while maintaining clinical precision, suggesting it could play a valuable role in perioperative temperature management, especially in procedures prioritizing patient comfort.\u003c/p\u003e \u003cp\u003eOur study demonstrates a strong correlation (Pearson r\u0026thinsp;=\u0026thinsp;0.75, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001) between axillary temperature measurements using the iThermonitor and lower esophageal temperatures, indicating a close alignment that is valuable for clinical practice. However, the concordance correlation coefficient (CCC) of 0.69 suggests that while the iThermonitor reliably complements esophageal monitoring, it does not achieve absolute agreement and should not be considered a complete surrogate in thoracoscopic surgery. This moderate CCC value may be attributed to physiological variances in core-to-peripheral temperature gradients and procedural factors such as surgical positioning and environmental conditions, which can introduce variability in temperature readings.\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e,\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e These findings underscore the importance of considering device limitations in specific clinical contexts while leveraging its non-invasive advantages for patient comfort and safety.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eReliability Assessment via ATE/LER Analysis\u003c/h2\u003e \u003cp\u003eOur analysis demonstrated that 94.3% of data points fell within the Allowable Total Error (ATE) zone of \u0026plusmn;\u0026thinsp;0.5\u0026deg;C, with 5.7% within the ATE-LER zone and none exceeding the Limits of Erroneous Results (LER) zone of \u0026plusmn;\u0026thinsp;1.5\u0026deg;C. These results highlight the iThermonitor\u0026rsquo;s exceptional clinical accuracy, aligning with FDA recommendations for ensuring clinically meaningful agreement.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eThis performance underscores the device\u0026rsquo;s reliability in thoracoscopic surgery, where minimizing invasive procedures is critical for enhancing patient comfort and safety. The iThermonitor\u0026rsquo;s adherence to these stringent error margins further supports its role as a viable non-invasive alternative to traditional methods, particularly in procedures prioritizing patient well-being.\u003c/p\u003e \u003cp\u003eIn our analysis of the ATE/LER plot, we identified five outliers where the discrepancy between axillary and esophageal temperatures exceeded 1.0\u0026deg;C. These outliers were traced back to a 42-year-old female patient with a BMI of 18.1 kg/m\u0026sup2;. whose initial axillary temperature recorded by the iThermonitor was 35.2\u0026deg;C and remained below 36.0\u0026deg;C throughout the procedure, while her esophageal temperature also stayed below 36.5\u0026deg;C. This observation suggests that factors such as low initial thermometer readings, female gender, and low BMI may contribute to increased discrepancies between the two measurement methods, consistent with a prior observational study that analyzed temperature readings from 526 adult patients in surgical wards.\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e These factors may be attributed to variations in physiological cycles and challenges in achieving a snug fit for the axillary probe in low-weight patients.\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003eTo address these discrepancies, future studies could investigate additional common factors contributing to these outliers and explore strategies to mitigate them, such as adjusted monitoring protocols or device modifications for specific patient demographics. This approach would enhance the accuracy and reliability of non-invasive temperature monitoring across diverse clinical settings.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eHypothermia Prediction Capabilities\u003c/h2\u003e \u003cp\u003eOur evaluation of the iThermonitor using a ROC curve with a diagnostic threshold of \u0026lt;\u0026thinsp;36.0\u0026deg;C demonstrated an AUC of 87.6%, indicating excellent diagnostic efficacy and aligning with established criteria where an AUC of 0.8\u0026ndash;0.9 reflects superior diagnostic value.\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003eAdditionally, we explored the diagnostic potential of a lower threshold for perioperative hypothermia. In line with the recent challenge by Sessler et al.\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003ewho suggested that a less aggressive warming target of 35.5\u0026deg;C may be as effective as the normothermic target of 37.0\u0026deg;C in preventing major cardiovascular and infectious complications, our results showed that the iThermonitor had a significant diagnostic value with an AUC of 88.0% at the 35.5\u0026deg;C threshold, with 100% sensitivity and 70.4% specificity (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.0001). These findings highlight the iThermonitor\u0026rsquo;s ability to accurately detect hypothermic events even at lower thresholds, potentially aiding in the development of targeted temperature maintenance strategies and reducing hypothermia-related adverse events.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003ePatient-Centered Benefits and Comfort\u003c/h2\u003e \u003cp\u003eInvasive temperature monitoring methods, such as those involving the pulmonary artery, lower esophagus, nasopharynx, bladder, and rectum, are widely recognized for causing patient discomfort and posing a risk of local trauma.\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e The development of non-invasive monitoring devices, like the wireless iThermonitor, has addressed these concerns by offering a more patient-friendly alternative. A recent review reported a relatively low incidence of adverse device effects (ADEs) for non-invasive vital sign monitoring devices, with no serious adverse reactions noted, highlighting the safety profile of such devices.\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003eThese ADEs typically manifest as mild skin symptoms such as itching, redness, and allergies, which are reversible by simple measures like changing the probe site or temporarily removing the device.\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eIn our study, we observed a 73.8% incidence of esophageal temperature probe bloodstaining, which may indicate localized mucosal injury. However, postoperative follow-ups on days two and three revealed no symptoms such as esophageal burning or hematemesis, suggesting that these minor injuries resolved without clinical consequence. Additionally, skin redness was observed at the axillary monitoring site in 45% of patients, which resolved within the second and third postoperative days without any blisters or ulcerations. Liu et al.\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003ereported a 5% incidence of skin adverse reactions related to the iThermonitor. The higher incidence of skin reactions in our study may be attributed to the specific patient positioning required for thoracoscopic surgery, where the side-lying position and the need to place the probe away from the surgical field may result in local compression. Nevertheless, the iThermonitor demonstrated a favorable safety profile, with no serious skin reactions recorded, aligning with the mentioned safety standards of non-invasive monitoring devices.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eLimitations and Future Research Directions\u003c/h2\u003e \u003cp\u003eOur study has several limitations and future research directions that should be considered. First, the study focused on thoracoscopic surgery in the lateral decubitus position, which limits the generalizability of our findings to more invasive procedures, such as open-chest surgery. Second, our results may not apply to patients with extreme BMI values, highlighting the need for demographic-specific calibrations. Third, while the iThermonitor demonstrated high accuracy in this study, its performance in other clinical settings or patient populations requires further validation.\u003c/p\u003e \u003cp\u003eFuture research could address these limitations by incorporating more comprehensive evaluations, such as endoscopic examinations, to assess mucosal damage caused by invasive temperature monitoring methods. Additionally, exploring patient-centered outcomes, such as comfort and anxiety reduction, would provide valuable insights into the benefits of non-invasive monitoring technologies. Finally, refining the device or protocol to address skin sensitivity, particularly in the lateral decubitus position, could enhance patient safety and acceptance, improving the accuracy and reliability of non-invasive temperature monitoring across diverse clinical contexts.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe iThermonitor's high sensitivity and specificity in detecting hypothermia make it a valuable tool for preventing and managing perioperative hypothermia. Its non-invasive design not only enhances patient comfort but also aligns with efforts to minimize procedural discomfort and maximize patient well-being. The device's ability to accurately reflect core body temperature, combined with its favorable safety profile, positions it as a promising alternative to traditional invasive methods. Future studies focusing on patient-reported outcomes and performance across diverse clinical settings will further solidify its role in advancing patient-centered care and optimizing perioperative temperature management.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAcknowledgments\u003c/p\u003e\n\u003cp\u003eWe thank XinXin Hao and Ying Liu for their assistance in data collection and follow-up.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThis work was supported by the Beijing Hospitals Authority\u0026rsquo;s Ascent Plan [grant number DFL20220203]. The funding organization had no role in the study design, data collection, or the decision to publish the results.\u003c/p\u003e\n\u003cp\u003eAuthor contributions\u003c/p\u003e\n\u003cp\u003eGuyan Wang: This author was the lead designer of the study and supervised all study phases. Yanhong Yan: This author provided significant input into the statistical analyses, manuscript drafting, and revisions. Jiao Geng: This author provided significant input into the manuscript drafting, and revisions. Xu Cui: This author assisted in executing the study and made valuable revisions to the manuscript. Zhihai Ju: This author assisted in executing the study and made valuable revisions to the manuscript. Each author has affirmed their contribution to this manuscript and has given consent for its submission.\u003c/p\u003e\n\u003cp\u003eEthics approval\u003c/p\u003e\n\u003cp\u003eThe clinical trial number is ChiCTR2300078340, and it is registered with the Chinese Clinical Trial Registration website, which can be accessed at Chinese Clinical Trial Register (ChiCTR).\u003c/p\u003e\n\u003cp\u003eData availability statement\u003c/p\u003e\n\u003cp\u003eThe dataset supporting the findings of this study is available upon reasonable request to the corresponding author, [Guyan Wang], at [[email protected]]. Requests for access to the data will be reviewed by the corresponding author and data access may be granted, subject to any necessary approvals and agreements to protect the privacy and confidentiality of participants.\u003c/p\u003e\n\u003cp\u003eDisclosure\u003c/p\u003e\n\u003cp\u003eThe authors report no conflicts of interest in this work. \u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eLaupland KB, Zahar JR, Adrie C, et al. Severe hypothermia increases the risk for intensive care unit-acquired infection. \u003cem\u003eClin Infect Dis\u003c/em\u003e. 2012;54(8):1064-1070. doi:10.1093/cid/cir1033\u003c/li\u003e\n\u003cli\u003eHarper CM, Andrzejowski JC, Alexander R. NICE and warm. \u003cem\u003eBr J Anaesth\u003c/em\u003e. 2008;101(3):293-295. doi:10.1093/bja/aen233\u003c/li\u003e\n\u003cli\u003eBoet S, Patey AM, Baron JS, et al. Factors that influence effective perioperative temperature management by anesthesiologists: a qualitative study using the Theoretical Domains Framework. \u003cem\u003eCan J Anesth\u003c/em\u003e. 2017;64(6):581-596. doi:10.1007/s12630-017-0845-9\u003c/li\u003e\n\u003cli\u003eMoola S, Lockwood C. Effectiveness of strategies for the management and/or prevention of hypothermia within the adult perioperative environment. \u003cem\u003eInt J Evid-Based Hea\u003c/em\u003e\u003cem\u003elthc\u003c/em\u003e. 2011;9(4):337-345. doi:10.1111/j.1744-1609.2011.00227.x\u003c/li\u003e\n\u003cli\u003ePu Y, Cen G, Sun J, et al. Warming with an underbody warming system reduces intraoperative hypothermia in patients undergoing laparoscopic gastrointestinal surgery: a randomized controlled study. \u003cem\u003eInt J Nurs Stud\u003c/em\u003e. 2014;51(2):181-189. doi:10.1016/j.ijnurstu.2013.05.013\u003c/li\u003e\n\u003cli\u003eKlauke N, Graff I, Fleischer A, et al. Effects of prehospital hypothermia on transfusion requirements and outcomes: a retrospective observatory trial. \u003cem\u003eB\u003c/em\u003e\u003cem\u003eMJ\u003c/em\u003e\u003cem\u003e Open\u003c/em\u003e. 2016;6(3):e009913. doi:10.1136/bmjopen-2015-009913\u003c/li\u003e\n\u003cli\u003eMahoney CB, Odom J. Maintaining intraoperative normothermia: a meta-analysis of outcomes with costs. \u003cem\u003eAANA J\u003c/em\u003e. 1999;67(2):155-163.\u003c/li\u003e\n\u003cli\u003eNiven DJ, Gaudet JE, Laupland KB, Mrklas KJ, Roberts DJ, Stelfox HT. Accuracy of peripheral thermometers for estimating temperature: a systematic review and meta-analysis. \u003cem\u003eAnn Intern Med\u003c/em\u003e. 2015;163(10):768-777. doi:10.7326/M15-1150\u003c/li\u003e\n\u003cli\u003eDolson CM, Harlow ER, Phelan DM, et al. Wearable Sensor Technology to Predict Core Body Temperature: A Systematic Review. \u003cem\u003eSensors-Basel\u003c/em\u003e. 2022;22(19):7639. doi:10.3390/s22197639\u003c/li\u003e\n\u003cli\u003eBrauer A, Fazliu A, Brandes IF, Vollnhals F, Grote R, Menzel M. Evaluation of the Temple Touch Pro noninvasive core-temperature monitoring system in 100 adults under general anesthesia: a prospective comparison with esophageal temperature. \u003cem\u003eJ Clin Monit Comput\u003c/em\u003e. 2023;37(1):29-36. doi:10.1007/s10877-022-00851-z\u003c/li\u003e\n\u003cli\u003eYang SM, Cho HY, Kim HS. Comparison of tracheal temperature and core temperature measurement in living donor liver transplant recipients: a clinical comparative study. \u003cem\u003eB\u003c/em\u003e\u003cem\u003eMC\u003c/em\u003e\u003cem\u003e Anesthesiol\u003c/em\u003e. 2022;22(1):315. doi:10.1186/s12871-022-01853-9\u003c/li\u003e\n\u003cli\u003eBrauer A, Fazliu A, Perl T, Heise D, Meissner K, Brandes IF. Accuracy of zero-heat-flux thermometry and bladder temperature measurement in critically ill patients. \u003cem\u003eSci Rep\u003c/em\u003e. 2020;10(1):21746. doi:10.1038/s41598-020-78753-w\u003c/li\u003e\n\u003cli\u003eBoisson M, Alaux A, Kerforne T, et al. Intra-operative cutaneous temperature monitoring with zero-heat-flux technique (3M SpotOn) in comparison with oesophageal and arterial temperature: A prospective observational study. \u003cem\u003eEur J Anaesth\u003c/em\u003e. 2018;35(11):825-830. doi:10.1097/EJA.0000000000000822\u003c/li\u003e\n\u003cli\u003eEvron S, Weissman A, Toivis V, et al. Evaluation of the Temple Touch Pro, a Novel Noninvasive Core-Temperature Monitoring System. \u003cem\u003eAnesth Analg\u003c/em\u003e. 2017;125(1):103-109. doi:10.1213/ANE.0000000000001695\u003c/li\u003e\n\u003cli\u003ePei L, Huang Y, Mao G, Sessler DI. Axillary Temperature, as Recorded by the iThermonitor WT701, Well Represents Core Temperature in Adults Having Noncardiac Surgery. \u003cem\u003eAnesth Analg\u003c/em\u003e. 2018;126(3):833-838. doi:10.1213/ANE.0000000000002706\u003c/li\u003e\n\u003cli\u003eXu R, Hu X, Sun Z, Zhu X, Tang Y. Incidence of postoperative hypothermia and shivering and risk factors in patients undergoing malignant tumor surgery: a retrospective study. \u003cem\u003eB\u003c/em\u003e\u003cem\u003eMC\u003c/em\u003e\u003cem\u003e Anesthesiol\u003c/em\u003e. 2023;23(1):31. doi:10.1186/s12871-023-01991-8\u003c/li\u003e\n\u003cli\u003eStuart CM, Dyas AR, Bronsert MR, et al. Perioperative hypothermia in robotic-assisted thoracic surgery: Incidence, risk factors, and associations with postoperative outcomes. \u003cem\u003eJ Thorac Cardiov\u003c/em\u003e\u003cem\u003easc\u003c/em\u003e\u003cem\u003e Sur\u003c/em\u003e\u003cem\u003eg\u003c/em\u003e. 2024;167(6):1979-1989.e1. doi:10.1016/j.jtcvs.2023.10.031\u003c/li\u003e\n\u003cli\u003eMekjavic IB, Rempel ME. Determination of esophageal probe insertion length based on standing and sitting height. \u003cem\u003eJ Appl Physiol\u003c/em\u003e. 1990;69(1):376-379. doi:10.1152/jappl.1990.69.1.376\u003c/li\u003e\n\u003cli\u003eSessler DI. Perioperative thermoregulation and heat balance. \u003cem\u003eThe Lancet\u003c/em\u003e. 2016;387(10038):2655-2664. doi:10.1016/S0140-6736(15)00981-2\u003c/li\u003e\n\u003cli\u003eJi Y, Han D, Han L, Xie S, Pan S. The Accuracy of a Wireless Axillary Thermometer for Core Temperature Monitoring in Pediatric Patients Having Noncardiac Surgery: An Observational Study. \u003cem\u003eJ Perianesth Nurs\u003c/em\u003e. 2021;36(6):685-689. doi:10.1016/j.jopan.2021.02.008\u003c/li\u003e\n\u003cli\u003eLiu Y, Liu C, Gao M, et al. Evaluation of a wearable wireless device with artificial intelligence, iThermonitor WT705, for continuous temperature monitoring for patients in surgical wards: a prospective comparative study. \u003cem\u003eB\u003c/em\u003e\u003cem\u003eMJ\u003c/em\u003e\u003cem\u003e Open\u003c/em\u003e. 2020;10(11):e039474. doi:10.1136/bmjopen-2020-039474\u003c/li\u003e\n\u003cli\u003eKalmar AF, Foubert L, Hendrickx JFA, et al. Influence of steep Trendelenburg position and CO2 pneumoperitoneum on cardiovascular, cerebrovascular, and respiratory homeostasis during robotic prostatectomy. \u003cem\u003eBr J Anaesth\u003c/em\u003e. 2010;104(4):433-439. doi:10.1093/bja/aeq018\u003c/li\u003e\n\u003cli\u003eKurz A, Sessler DI, Christensen R, Dechert M. Heat balance and distribution during the core-temperature plateau in anesthetized humans. \u003cem\u003eAnesthesiology\u003c/em\u003e. 1995;83(3):491-499. doi:10.1097/00000542-199509000-00007\u003c/li\u003e\n\u003cli\u003eZweig MH, Campbell G. Receiver-operating characteristic (ROC) plots: a fundamental evaluation tool in clinical medicine. \u003cem\u003eClin Chem\u003c/em\u003e. 1993;39(4):561-577.\u003c/li\u003e\n\u003cli\u003eSessler DI, Pei L, Li K, et al. Aggressive intraoperative warming versus routine thermal management during non-cardiac surgery (PROTECT): a multicentre, parallel group, superiority trial. \u003cem\u003eLancet\u003c/em\u003e. 2022;399(10337):1799-1808. doi:10.1016/S0140-6736(22)00560-8\u003c/li\u003e\n\u003cli\u003eSessler DI. Perioperative Temperature Monitoring. \u003cem\u003eAnesthesiology\u003c/em\u003e. 2021;134(1):111-118. doi:10.1097/ALN.0000000000003481\u003c/li\u003e\n\u003cli\u003eAagaard N, Larsen AT, Aasvang EK, Meyhoff CS. The impact of continuous wireless monitoring on adverse device effects in medical and surgical wards: a review of current evidence. \u003cem\u003eJ Clin Monit Comput\u003c/em\u003e. 2023;37(1):7-17. doi:10.1007/s10877-022-00899-x\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-clinical-monitoring-and-computing","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Journal of Clinical Monitoring and Computing](https://www.springer.com/journal/10877)","snPcode":"10877","submissionUrl":"https://submission.nature.com/new-submission/10877/3","title":"Journal of Clinical Monitoring and Computing","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Non-invasive monitoring, Patient preference, Patient comfort, Accuracy, Hypothermia","lastPublishedDoi":"10.21203/rs.3.rs-6685457/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6685457/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose: \u003c/strong\u003eIn thoracoscopic surgery, temperature monitoring is essential but traditionally relies on invasive methods such as esophageal or rectal thermometry, which can lead to local mucosal damage and patient discomfort. This clinical trial evaluates the iThermonitor, a non-invasive, wireless, wearable axillary temperature monitoring device, as a potential alternative to traditional invasive methods, aiming to enhance patient preference and comfort by offering a non-invasive option that minimizes procedural discomfort while maintaining clinical precision.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePatients and methods: \u003c/strong\u003eWe enrolled 80 adult patients scheduled for thoracoscopic surgery under general anesthesia between December 1, 2023, to May 31, 2024. The iThermonitor was used to measure axillary temperature, while lower esophageal temperature served as the reference standard. Temperature readings were recorded every 3 minutes. The primary outcome was the accuracy of the iThermonitor compared to lower esophageal temperature.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e Analysis of 3536 temperature pairs showed the iThermonitor demonstrated high accuracy, with 93.96% of readings within ±0.5°C of the esophageal probe (95% CI: 91.94%–95.85%). The Pearson correlation coefficient was 0.75 (\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.0001), and the concordance correlation coefficient was 0.69. The ATE/LER analysis indicated 94.3% of data points fell within the ATE zone (±0.5°C), with none in the LER zone (\u0026gt;1.5°C). The device showed strong predictive value for hypothermia (\u0026lt;36.0°C) with an AUC of 0.876. Notably, the esophageal probe exhibited bloodstaining in 73.8% of cases, whereas the iThermonitor caused only transient skin redness in 45% of patients, resolving completely postoperatively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion: \u003c/strong\u003eThe iThermonitor is a reliable and accurate non-invasive alternative to traditional invasive temperature monitoring methods in thoracoscopic surgery. It effectively detects perioperative hypothermia and offers significant patient-centered benefits, including enhanced comfort and safety. These findings support the potential of the iThermonitor to improve patient preference and adherence in clinical practice.\u003c/p\u003e","manuscriptTitle":"iThermonitor: A Wearable Non-Invasive High-Precision Alternative to Traditional Temperature Monitoring in Thoracoscopic Surgery of Lateral Decubitus Position","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-09 11:20:37","doi":"10.21203/rs.3.rs-6685457/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-06-22T20:44:33+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-17T16:37:51+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"175343501557143443438020852071859886656","date":"2025-06-03T17:23:55+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-02T18:38:02+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-05-19T01:38:27+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-05-19T01:37:57+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Clinical Monitoring and Computing","date":"2025-05-17T07:53:48+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-clinical-monitoring-and-computing","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Journal of Clinical Monitoring and Computing](https://www.springer.com/journal/10877)","snPcode":"10877","submissionUrl":"https://submission.nature.com/new-submission/10877/3","title":"Journal of Clinical Monitoring and Computing","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"9709d042-5639-4b96-adac-0b4b233cb98c","owner":[],"postedDate":"June 9th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-08-14T07:38:19+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-09 11:20:37","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6685457","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6685457","identity":"rs-6685457","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}