The effect of controlled respiratory rate on end-tidal co₂, arterial blood gases, and hemodynamic parameters during elective laparoscopic surgery: a comparative observational study

The effect of controlled respiratory rate on end-tidal co₂, arterial blood gases, and hemodynamic parameters during elective laparoscopic surgery: a comparative observational study | 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 Short Report The effect of controlled respiratory rate on end-tidal co₂, arterial blood gases, and hemodynamic parameters during elective laparoscopic surgery: a comparative observational study Mohammed Hayek, Ibrahim Ghoul, Nizar Said, Majdi Dwikat, Aidah Alkaissi, and 11 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7242284/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Laparoscopic surgery requires CO₂ insufflation to create pneumoperitoneum, which may lead to significant physiological changes, particularly in respiratory parameters such as end-tidal CO₂ (ETCO₂) and arterial blood gases (ABG). Intraoperative ventilation strategies, particularly respiratory rate, can influence CO₂ retention and acid-base balance. However, comparative evidence regarding optimal respiratory rates during laparoscopy remains limited. Aim To compare the effects of two controlled respiratory rates (14 vs. 20 breaths per minute) on ETCO₂ and ABG parameters in adult patients undergoing elective laparoscopic surgery. Methods This prospective comparative study included 60 adult patients scheduled for elective laparoscopic surgeries at Darwish Nazzal Governmental Hospital, Palestine, between June 2023 and January 2024. Patients were assigned to either the RR14 or RR20 group (30 patients each). ETCO₂, ABG parameters, vital signs, and peak airway pressure were measured at baseline, 15 minutes after insufflation, and post-disinflation. Data were analyzed using SPSS v23 with independent t-tests, repeated measures ANOVA, and Pearson correlation tests. Results The RR14 group showed significantly higher ETCO₂ levels than the RR20 group at all time points (p < 0.001). During insufflation, the RR14 group had higher PaCO₂ (44.08 vs. 41.28 mmHg; p = 0.004) and lower pH (7.36 vs. 7.37; p = 0.008). Longer procedure duration and higher intra-abdominal pressure were positively correlated with elevated ETCO₂ and PaCO₂ and negatively with pH. Smoking history was associated with impaired baseline respiratory values (p < 0.001). Conclusion Lower respiratory rates during laparoscopic surgery are associated with increased CO₂ retention and mild respiratory acidosis. Tailoring respiratory rate settings based on patient characteristics and intraoperative conditions may enhance physiological stability and safety. Laparoscopic surgery end-tidal CO₂ arterial blood gases respiratory rate ventilation CO₂ insufflation intra-abdominal pressure Background Laparoscopic surgery, a minimally invasive surgical technique, has become the standard of care for various abdominal procedures due to its reduced postoperative pain, shorter hospital stays, and faster recovery [ 1 , 2 ]. A key feature of this technique is the use of carbon dioxide (CO₂) insufflation to create pneumoperitoneum, allowing for better visualization and surgical access [ 1 – 3 ]. However, CO₂ insufflation can significantly affect respiratory physiology, particularly through increased intra-abdominal pressure and CO₂ absorption, potentially leading to hypercapnia and acidosis [ 2 – 5 ]. Intraoperative monitoring of respiratory parameters, particularly end-tidal CO₂ (ETCO₂) and arterial blood gases (ABG), is therefore essential for patient safety and optimal anesthetic management [ 2 – 4 ]. Existing literature has established that changes in ventilation strategy, particularly respiratory rate, can influence CO₂ elimination and acid-base balance during laparoscopic procedures [ 2 , 4 , 6 ]. While several studies have examined the effects of pneumoperitoneum on pulmonary function and ABG parameters, there is limited evidence comparing different intraoperative respiratory rate settings and their direct impact on ETCO₂ and ABG values [ 2 , 4 ]. Moreover, factors such as procedure duration, intra-abdominal pressure, and smoking history may exacerbate or alter these physiological changes, yet these variables are often underexplored in clinical studies [ 2 – 4 ]. This gap in the literature leads to a critical problem: the lack of standardized ventilatory approaches during laparoscopic surgery that are tailored to individual patient needs and intraoperative dynamics [ 2 , 4 , 7 ]. Without clear guidelines, patients may be exposed to unnecessary physiological stress, increasing the risk of complications, especially in those with compromised respiratory reserves [ 2 , 4 , 7 ]. This study addresses the problem by investigating how two commonly used respiratory rates (14 and 20 breaths per minute) affect ETCO₂ and ABG parameters during elective laparoscopic surgery [ 2 , 4 ]. It also explores the roles of intra-abdominal pressure, procedure duration, and smoking history in shaping these outcomes [ 2 – 4 ]. The significance of this study lies in its potential to inform ventilatory management strategies during laparoscopy, benefiting anesthesiologists, surgeons, and patients by enhancing intraoperative safety and postoperative recovery [ 2 , 4 , 6 , 7 ]. The aim of this study is to evaluate the effects of two controlled respiratory rates (14 vs. 20 breaths per minute) on physiological responses in adult patients undergoing elective laparoscopic surgery. Specifically, the study examines differences in end-tidal CO₂ (ETCO₂) levels and arterial blood gas (ABG) parameters (pH, PaCO₂, PaO₂, HCO₃⁻) before, during, and after CO₂ insufflation, as well as variations in vital signs and peak airway pressure across these surgical phases. Additionally, the study explores the influence of procedure duration and intra-abdominal pressure on ETCO₂ and ABG values, and investigates the impact of smoking history on baseline respiratory and blood gas measurements. Methodology Study Design This prospective comparative study was conducted to evaluate the effect of controlled respiratory rates on arterial blood gases (ABG) and end-tidal CO₂ (ETCO₂) levels during elective laparoscopic surgeries. It was carried out in the operating rooms of Darwish Nazzal Governmental Hospital, Qalqilia, Palestine, from June 2023 to January 2024. Sample Size A total of 60 adult patients undergoing elective laparoscopic surgery were included. Participants were conveniently sampled and divided into two groups based on ventilator settings: RR14 (n = 30) and RR20 (n = 30). The sample size was determined using a standard formula considering prior literature, aiming for 80% power to detect clinically relevant differences. Inclusion and Exclusion Criteria Eligible participants were adults aged 18–60 years, classified as ASA I or II, and scheduled for laparoscopic cholecystectomy or appendectomy under general anesthesia. Patients were excluded if they had respiratory or cardiac diseases, liver or kidney dysfunction, pregnancy, BMI ≥ 30 kg/m², or were on medications affecting respiratory or cardiovascular function. Data Collection Following ethical approval and patient consent, demographic and clinical data were recorded. An arterial line was placed for ABG sampling. ETCO₂, ABG parameters, vital signs, and peak airway pressure were measured at baseline, 15 minutes after insufflation, and post-disinflation. Surgery duration and intra-abdominal pressure were also documented. Data Analysis Statistical analysis was performed using SPSS version 23. Descriptive statistics, Chi-square, independent and paired t-tests, repeated measures ANOVA, and Pearson correlations were used. A significance level of p < 0.05 was applied. Ethical Considerations Ethical approval was obtained from An-Najah National University (Ref: Mas. July. 2023.3) and the Palestinian Ministry of Health. Written informed consent was secured from all participants, with confidentiality and voluntary participation fully respected. Results A total of 60 adult patients undergoing elective laparoscopic surgery were included in this study. Participants were randomly allocated into two groups based on intraoperative respiratory rate settings: the RR14 group (n = 30) and the RR20 group (n = 30). The overall sample consisted of 22 males (36.7%) and 38 females (63.3%), with a mean age of 36 years, mean height of 170 cm, and mean weight of 67 kg. The majority of patients (86.7%) underwent laparoscopic cholecystectomy, while the remaining 13.3% underwent laparoscopic appendectomy. Approximately 33.3% of participants had a positive smoking history, and all patients had no prior medical history. No statistically significant differences were found between the two groups regarding baseline demographic characteristics (p > 0.05). End-Tidal CO₂ (ETCO₂) Levels Comparative analysis of ETCO₂ levels revealed statistically significant differences between the two respiratory rate groups at all surgical phases (Table 2 ). Prior to insufflation, the RR14 group demonstrated significantly higher ETCO₂ levels (Mean = 35.87) compared to the RR20 group (Mean = 33.97; p = 0.006). During insufflation (15 minutes after CO₂ insufflation), ETCO₂ further increased in both groups, but remained significantly higher in the RR14 group (Mean = 40.67) than in the RR20 group (Mean = 36.63; p < 0.001). After CO₂ venting (disinflation), the RR14 group again showed significantly higher ETCO₂ values (Mean = 38.7) versus the RR20 group (Mean = 34.03; p < 0.001) (Table 1 ). Table 1 Comparisons between the two respiratory rate groups in ETCO₂ and ABG values during insufflation (n = 60) Variable RR14 (n = 30) RR20 (n = 30) Total (N = 60) P-value ETCO₂ (mmHg) 40.67 ± 3.53 36.63 ± 2.59 38.65 ± 3.68 < 0.001 pH 7.36 ± 0.03 7.37 ± 0.02 7.36 ± 0.03 0.008 PaCO₂ (mmHg) 44.08 ± 4.27 41.28 ± 2.88 42.68 ± 3.88 0.004 HCO₃ (mmol/L) 23.89 ± 1.01 24.2 ± 0.74 24.04 ± 0.89 0.185 Note: Data are presented as mean ± SD. Statistical significance tested with independent samples t-test. Table 2 Changes in ETCO₂, ABG Values, and Peak Airway Pressure Across Surgical Phases (N = 60) Variable Before Insufflation During Insufflation After CO₂ Venting P-value ETCO₂ (mmHg) 34.92 ± 2.71 38.65 ± 3.68 36.37 ± 3.47 < 0.001 pH 7.39 ± 0.02 7.36 ± 0.03 – < 0.001 PaCO₂ (mmHg) 38.84 ± 2.77 42.68 ± 3.88 – < 0.001 PaO₂ (mmHg) 83.96 ± 3.9 90.22 ± 4.23 – < 0.001 Peak Airway Pressure (cmH₂O) 13.87 ± 1.6 23.48 ± 3.22 17.09 ± 2.13 < 0.001 Note: Repeated measures ANOVA used for comparisons. Values represent mean ± SD. Arterial Blood Gas (ABG) Parameters No significant differences were observed between the two groups in ABG parameters before insufflation (p > 0.05). However, during insufflation, significant group differences emerged. The RR14 group had lower pH values (Mean = 7.36) compared to the RR20 group (Mean = 7.37; p = 0.008) and higher PaCO₂ levels (44.08 vs. 41.28 mmHg; p = 0.004). No significant differences were noted in PaO₂ and HCO₃⁻ values between groups during this phase. Paired comparisons before and during insufflation across the entire sample showed significant physiological changes. pH levels declined significantly from 7.39 to 7.36 (p < 0.001), while PaCO₂ increased from 38.84 to 42.68 mmHg (p < 0.001). PaO₂ significantly increased (83.96 to 90.22 mmHg; p < 0.001), and HCO₃⁻ slightly decreased (24.29 to 24.04 mmol/L; p < 0.001), suggesting mild respiratory acidosis during insufflation. Vital Signs and Peak Airway Pressure Post-hoc pairwise comparisons showed significant changes in vital signs across surgical phases. Diastolic blood pressure increased during insufflation (Mean = 79.85 mmHg), then decreased post-disinflation (Mean = 75.8 mmHg; p < 0.001). Heart rate also increased significantly during insufflation (Mean = 83.63 bpm) compared to pre- (78.9 bpm) and post-insufflation (78.48 bpm) values (p < 0.001). Similarly, SpO₂ improved during insufflation (Mean = 98.85%) compared to before (97.02%) and after (98.2%) insufflation (p < 0.001). Peak airway pressure significantly increased during insufflation (Mean = 23.48 cmH₂O), then decreased post-insufflation (Mean = 17.09 cmH₂O) and was lowest before insufflation (Mean = 13.87 cmH₂O), with all comparisons showing p < 0.001. Correlations with Procedure Duration and Intra-abdominal Pressure Pearson correlation analysis indicated that procedure duration had a significant positive correlation with ETCO₂ (r = 0.376, p = 0.003) and PaCO₂ (r = 0.368, p = 0.004), and a significant negative correlation with pH (r = -0.294, p = 0.023). Intra-abdominal pressure also showed significant positive correlations with ETCO₂ (r = 0.369, p = 0.004) and PaCO₂ (r = 0.481, p < 0.001), and a significant negative correlation with pH (r = -0.308, p = 0.017). These findings indicate that longer procedures and higher intra-abdominal pressures are associated with greater CO₂ retention and acidosis. Impact of Smoking History Patients with a history of smoking had significantly higher baseline ETCO₂ levels (Mean = 37.7 vs. 33.53; p < 0.001), lower pH (7.34 vs. 7.38; p < 0.001), lower PaO₂ (81.91 vs. 84.98 mmHg; p = 0.003), and higher PaCO₂ (41.78 vs. 37.37 mmHg; p < 0.001) compared to non-smokers. This suggests a compromised baseline respiratory status among smokers. Discussion This study demonstrates that increasing the intraoperative respiratory rate from 14 to 20 breaths per minute during elective laparoscopic surgery significantly reduces ETCO₂ and PaCO₂ levels, while mitigating the degree of respiratory acidosis, as evidenced by higher intraoperative pH values in the RR20 group. These findings align with recent literature indicating that higher respiratory rates facilitate more effective CO₂ elimination during laparoscopic procedures, thereby reducing the risk of hypercapnia and acidosis [ 8 , 9 ]. The observed increases in ETCO₂, PaCO₂, and peak airway pressure during insufflation are consistent with established effects of pneumoperitoneum on respiratory mechanics and gas exchange [ 3 , 8 – 10 ]. Notably, the positive correlations between procedure duration, intra-abdominal pressure, and CO₂ retention reinforce the importance of individualized ventilatory strategies, particularly for longer or more complex surgeries [ 3 , 8 ]. The impact of smoking history on baseline respiratory parameters further highlights the need for tailored perioperative management in patients with compromised pulmonary function [ 8 ]. Future research should explore optimal ventilatory settings across diverse patient populations and surgical contexts, as well as the long-term clinical outcomes of intraoperative respiratory management [ 8 – 10 ]. Clinically, these results support the adoption of higher respiratory rates during laparoscopic surgery to enhance intraoperative safety, especially in patients at risk for CO₂ retention or acid-base disturbances [ 8 , 9 ]. Based on the findings of this study, it is recommended that higher intraoperative respiratory rates, such as 20 breaths per minute, be considered during elective laparoscopic surgeries to help maintain optimal end-tidal CO₂ and arterial blood gas levels, thereby reducing the risk of CO₂ retention and respiratory acidosis. Anesthesiologists should closely monitor ETCO₂ and ABG parameters, especially in cases with longer procedure durations or elevated intra-abdominal pressures. Special attention should be given to patients with a positive smoking history, as they may exhibit impaired baseline respiratory function and be more susceptible to ventilation-related complications. Tailoring ventilatory management to patient-specific risk factors and surgical variables may improve intraoperative physiological stability and reduce postoperative complications. Limitations This study has several limitations that should be considered when interpreting the findings. First, although the sample size of 60 patients was sufficient for detecting significant differences, a larger multicenter study would enhance the generalizability of the results. Second, the study design was observational and non-randomized, which may introduce selection bias or unmeasured confounding factors. Third, the respiratory rates were fixed at two discrete levels without individualized adjustments based on patient characteristics or real-time monitoring feedback, which may not reflect the complexity of clinical practice. Finally, postoperative outcomes such as recovery time, complications, or long-term respiratory function were not assessed, limiting the ability to evaluate the clinical significance of intraoperative physiological differences. Future research should aim to address these limitations and further investigate the long-term implications of intraoperative ventilatory strategies. Conclusion This comparative observational study demonstrates that respiratory rate significantly influences end-tidal CO₂ levels and arterial blood gas parameters in patients undergoing elective laparoscopic surgery. Patients ventilated at a lower respiratory rate (RR14) exhibited higher ETCO₂ and PaCO₂ levels and lower pH values during and after insufflation, indicating greater CO₂ retention and mild respiratory acidosis compared to those ventilated at RR20. Additionally, vital signs such as heart rate and diastolic blood pressure showed significant intraoperative changes, with peak airway pressure rising during insufflation and correlating with elevated CO₂ levels. Longer procedure duration and increased intra-abdominal pressure were both associated with worsened gas exchange and acidosis. Furthermore, smoking history was linked to impaired baseline respiratory function, reflected in higher ETCO₂ and PaCO₂, and lower pH and PaO₂. These findings underscore the importance of tailoring intraoperative ventilatory strategies to minimize physiological disturbances, particularly in patients with risk factors such as prolonged surgery, high insufflation pressures, or a history of smoking. Abbreviations Abbreviation Full Term ABG Arterial Blood Gas ASA American Society of Anesthesiologists BMI Body Mass Index CO₂ Carbon Dioxide DBP Diastolic Blood Pressure ETCO₂ End-Tidal Carbon Dioxide HR Heart Rate HCO₃ Bicarbonate IRB Institutional Review Board PaCO₂ Partial Pressure of Carbon Dioxide in Arterial Blood PaO₂ Partial Pressure of Oxygen in Arterial Blood P-value Probability Value (Statistical Significance) RR Respiratory Rate RR14 Respiratory Rate 14 breaths/min group RR20 Respiratory Rate 20 breaths/min group SBP Systolic Blood Pressure SD Standard Deviation SPSS Statistical Package for the Social Sciences SpO₂ Peripheral Oxygen Saturation Declarations Competing interests The authors declare no competing interests. Ethics approval and consent to participate The Institutional Review Board at An-Najah National University approved the research, and permission was obtained from the hospital. This study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. All methods were performed in accordance with the relevant guidelines and regulations sectors. Consent for publication Not applicable. Consent to participate Written informed consent was obtained from all participants after providing a full explanation of the study's purpose, procedures, and their rights as participants. Confidentiality and anonymity were strictly maintained. Participants were assured that their responses would be used solely for research purposes and that they could withdraw from the study at any time without any consequences. Additionally, formal requests for study approval were submitted and granted by the administrations of the participating hospitals, ensuring full institutional support and transparency. Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Data Availability The data that support the findings of this study are available from the corresponding author upon a reasonable request. Clinical trial registration Clinical trial number: not applicable Acknowledgements The authors would like to thank An-Najah National University (www.najah.edu) for the technical support provided to publish the present manuscript Author contributions M.H., N.S. I.G, A. A (Ahmad Ayed), M.D and M.S and A.A (Aidah Alkaissi). conceived and planned the experiments and performed the measurements, I.G, R.Z., M.H and M.S. were involved in planning and supervised the work, B.H, S.Q, R.Z, B.S, A.B and M.S aided in interpreting the results and worked on the manuscript. F.H, E.A, J.Q, I.T and M.S final draft editing. All authors discussed the results and commented on the manuscript. References Manangi M, Gangadharaiah R, Chikkanayakanahalli S, Naik M, Jayappa AB. A Study on Effects of Leaking Carbon Dioxide Gas on Surgeons during Laparoscopic Surgeries. World J Laparosc Surg DVD 2021. Masum A, Kalam F, Alam M. Respiratory Changes under Spinal Anaesthesia for Laparoscopic Gynaecological Procedures- a comparison with General Anaesthesia. J Bangladesh Soc Anaesthesiologists 2021. Kajiwara M, Nakashima R, Yoshimura F, Hasegawa S. Impact of AirSeal® insufflation system on respiratory and circulatory dynamics during laparoscopic abdominal surgery. Updates Surg. 2022;74:2003–9. Pan X, Wang D. Effect of different positive end-expiratory pressure levels in patients undergoing laparoscopic cholecystectomy under general anesthesia. Pakistan J Med Sci. 2025;41:719–23. Iwasaka H, Miyakawa H, Yamamoto H, Kitano T, Taniguchi K, Honda N. Respiratory mechanics and arterial blood gases during and after laparoscopic cholecystectomy. Can J Anaesth = J canadien d'anesthesie. 1997;43 2:129–33. Jo Y, Kim J, Park C, Chang Y, Kwak H. The Effect of Ventilation Strategy on Arterial and Cerebral Oxygenation During Laparoscopic Bariatric Surgery. Obes Surg. 2016;26:339–44. Yessenbayeva G, Meyerbekova A, Kim S, Zhumabayev M, Berdiyarova G, Shalekenov S, Zharlyganova D, Mukatova I, Yukhnevich Y, Klyuyev D et al. Impact of a positive end-expiratory pressure on oxygenation, respiratory compliance, and hemodynamics in obese patients undergoing laparoscopic surgery in reverse Trendelenburg position: a systematic review and meta-analysis of randomized controlled trials. BMC Anesthesiol 2025, 25. Yildiz A, Kilinc G, Sungurtekin H, Karaduman S, Birsen O. Impact of positive end-expiratory pressure with alveolar recruitment maneuver on respiratory and oxygenation parameters of patients during laparoscopic bariatric surgery. Eur Rev Med Pharmacol Sci. 2022;26 24:9170–9. Xie P, Li Z, Tian Z. The optimal combination of mechanical ventilator parameters under general anesthesia in obese patients undergoing laparoscopic surgery. J Clin Anesth. 2016;34:290–4. Vasudevan V. Abstract No.: ABS3339: Effects of volume controlled and pressure controlled volume guaranteed modes of ventilation on respiratory dynamics during laparoscopic surgery in children: A prospective observational study. Indian J Anaesth 2022, 66. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted 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-7242284","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Short Report","associatedPublications":[],"authors":[{"id":499193920,"identity":"5cebb8ee-80f1-47bf-939a-6eafbc39a558","order_by":0,"name":"Mohammed Hayek","email":"","orcid":"","institution":"An Najah National University","correspondingAuthor":false,"prefix":"","firstName":"Mohammed","middleName":"","lastName":"Hayek","suffix":""},{"id":499193921,"identity":"83696cd9-9bfc-4ca8-b678-748072277fc6","order_by":1,"name":"Ibrahim Ghoul","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyUlEQVRIiWNgGAWjYBACNjBisJADEgnMQIKxgUgtEsbEa2GAakkEqSROCx8D+7UHH9sk0rezH3j4uYDBRnbDAYJW8JQbzmyTyN3Zk5AsPYMhzZgYLWnSvEAtGw4kJEjzMBxOJFpLusH5B8m/eRj+E6OF/RhIS4LBjYQ0oC0HiNDCzMMmOeOchOGGGw/SrHkMko1nEtIi397+TOJDmY28wfmc5Ns8FXayfYS0MDDzGEBZPAkMDAb4lMIB+wMYg6Dxo2AUjIJRMEIBAHH+O6jzJ9NsAAAAAElFTkSuQmCC","orcid":"","institution":"An Najah National University Hospital","correspondingAuthor":true,"prefix":"","firstName":"Ibrahim","middleName":"","lastName":"Ghoul","suffix":""},{"id":499193922,"identity":"c9392e9a-1631-44a9-81cb-e5aca9e4303e","order_by":2,"name":"Nizar Said","email":"","orcid":"","institution":"An Najah National University","correspondingAuthor":false,"prefix":"","firstName":"Nizar","middleName":"","lastName":"Said","suffix":""},{"id":499193923,"identity":"7185a7b4-d5c6-4c62-904c-1f501908af64","order_by":3,"name":"Majdi Dwikat","email":"","orcid":"","institution":"An Najah National University","correspondingAuthor":false,"prefix":"","firstName":"Majdi","middleName":"","lastName":"Dwikat","suffix":""},{"id":499193924,"identity":"642afedf-1862-4be0-8da3-6b59ca31515b","order_by":4,"name":"Aidah Alkaissi","email":"","orcid":"","institution":"An Najah National University","correspondingAuthor":false,"prefix":"","firstName":"Aidah","middleName":"","lastName":"Alkaissi","suffix":""},{"id":499193925,"identity":"48889701-2b0c-454e-b600-7c1607f68be5","order_by":5,"name":"Ahmad Ayed","email":"","orcid":"","institution":"Arab American University","correspondingAuthor":false,"prefix":"","firstName":"Ahmad","middleName":"","lastName":"Ayed","suffix":""},{"id":499193926,"identity":"429aa550-43e7-4b78-b501-6803b313b3a5","order_by":6,"name":"Bahaaeddin M. Hammad","email":"","orcid":"","institution":"Arab American University","correspondingAuthor":false,"prefix":"","firstName":"Bahaaeddin","middleName":"M.","lastName":"Hammad","suffix":""},{"id":499193927,"identity":"90f7c69f-9145-4bea-9a6b-7336de02304c","order_by":7,"name":"Shurouq Ghalib Qadous","email":"","orcid":"","institution":"An Najah National University","correspondingAuthor":false,"prefix":"","firstName":"Shurouq","middleName":"Ghalib","lastName":"Qadous","suffix":""},{"id":499193928,"identity":"5b4dc9a6-eebf-4574-9bae-19ea45d2e326","order_by":8,"name":"Rasha S. abu Zaitoun","email":"","orcid":"","institution":"An Najah National University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Rasha","middleName":"S. abu","lastName":"Zaitoun","suffix":""},{"id":499193929,"identity":"03002ef0-0d31-4b1a-a57f-fa07a5b3ee26","order_by":9,"name":"Basma Salameh","email":"","orcid":"","institution":"Arab American University","correspondingAuthor":false,"prefix":"","firstName":"Basma","middleName":"","lastName":"Salameh","suffix":""},{"id":499193930,"identity":"0bb4fba6-9670-44af-8052-2a664051d98e","order_by":10,"name":"Ahmad Batran","email":"","orcid":"","institution":"Ahliya University","correspondingAuthor":false,"prefix":"","firstName":"Ahmad","middleName":"","lastName":"Batran","suffix":""},{"id":499193931,"identity":"a407be5c-f467-478d-891c-b40685f71e77","order_by":11,"name":"Fatima Herzallah","email":"","orcid":"","institution":"An Najah National University","correspondingAuthor":false,"prefix":"","firstName":"Fatima","middleName":"","lastName":"Herzallah","suffix":""},{"id":499193932,"identity":"ab6c2b3a-bbad-420b-8d3b-afb61a858e0f","order_by":12,"name":"Eman Alshawish","email":"","orcid":"","institution":"An Najah National University","correspondingAuthor":false,"prefix":"","firstName":"Eman","middleName":"","lastName":"Alshawish","suffix":""},{"id":499193933,"identity":"daeb2404-b24f-4687-8023-6f65f889c9dc","order_by":13,"name":"Jamal Qaddumi","email":"","orcid":"","institution":"An Najah National University","correspondingAuthor":false,"prefix":"","firstName":"Jamal","middleName":"","lastName":"Qaddumi","suffix":""},{"id":499193935,"identity":"f8ad4dc4-a89b-400d-bf27-8f860cc0ef25","order_by":14,"name":"Imad Thultheen","email":"","orcid":"","institution":"An Najah National University","correspondingAuthor":false,"prefix":"","firstName":"Imad","middleName":"","lastName":"Thultheen","suffix":""},{"id":499193938,"identity":"35002fdd-c4ae-4d27-8c8b-9abd30f35e85","order_by":15,"name":"Mohammed Souqi","email":"","orcid":"","institution":"Palestinian Ministry of Health","correspondingAuthor":false,"prefix":"","firstName":"Mohammed","middleName":"","lastName":"Souqi","suffix":""}],"badges":[],"createdAt":"2025-07-29 10:38:30","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7242284/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7242284/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":90661939,"identity":"12043d3d-881c-4082-8776-2f9d3a8fa090","added_by":"auto","created_at":"2025-09-05 11:39:05","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":824062,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7242284/v1/aeed2406-db48-4aad-8ae8-047d34992511.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The effect of controlled respiratory rate on end-tidal co₂, arterial blood gases, and hemodynamic parameters during elective laparoscopic surgery: a comparative observational study","fulltext":[{"header":"Background","content":"\u003cp\u003eLaparoscopic surgery, a minimally invasive surgical technique, has become the standard of care for various abdominal procedures due to its reduced postoperative pain, shorter hospital stays, and faster recovery [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. A key feature of this technique is the use of carbon dioxide (CO₂) insufflation to create pneumoperitoneum, allowing for better visualization and surgical access [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. However, CO₂ insufflation can significantly affect respiratory physiology, particularly through increased intra-abdominal pressure and CO₂ absorption, potentially leading to hypercapnia and acidosis [\u003cspan additionalcitationids=\"CR3 CR4\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Intraoperative monitoring of respiratory parameters, particularly end-tidal CO₂ (ETCO₂) and arterial blood gases (ABG), is therefore essential for patient safety and optimal anesthetic management [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Existing literature has established that changes in ventilation strategy, particularly respiratory rate, can influence CO₂ elimination and acid-base balance during laparoscopic procedures [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. While several studies have examined the effects of pneumoperitoneum on pulmonary function and ABG parameters, there is limited evidence comparing different intraoperative respiratory rate settings and their direct impact on ETCO₂ and ABG values [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Moreover, factors such as procedure duration, intra-abdominal pressure, and smoking history may exacerbate or alter these physiological changes, yet these variables are often underexplored in clinical studies [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. This gap in the literature leads to a critical problem: the lack of standardized ventilatory approaches during laparoscopic surgery that are tailored to individual patient needs and intraoperative dynamics [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Without clear guidelines, patients may be exposed to unnecessary physiological stress, increasing the risk of complications, especially in those with compromised respiratory reserves [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. This study addresses the problem by investigating how two commonly used respiratory rates (14 and 20 breaths per minute) affect ETCO₂ and ABG parameters during elective laparoscopic surgery [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. It also explores the roles of intra-abdominal pressure, procedure duration, and smoking history in shaping these outcomes [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The significance of this study lies in its potential to inform ventilatory management strategies during laparoscopy, benefiting anesthesiologists, surgeons, and patients by enhancing intraoperative safety and postoperative recovery [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe aim of this study is to evaluate the effects of two controlled respiratory rates (14 vs. 20 breaths per minute) on physiological responses in adult patients undergoing elective laparoscopic surgery. Specifically, the study examines differences in end-tidal CO₂ (ETCO₂) levels and arterial blood gas (ABG) parameters (pH, PaCO₂, PaO₂, HCO₃⁻) before, during, and after CO₂ insufflation, as well as variations in vital signs and peak airway pressure across these surgical phases. Additionally, the study explores the influence of procedure duration and intra-abdominal pressure on ETCO₂ and ABG values, and investigates the impact of smoking history on baseline respiratory and blood gas measurements.\u003c/p\u003e"},{"header":"Methodology","content":"\u003cp\u003e\u003cb\u003eStudy Design\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis prospective comparative study was conducted to evaluate the effect of controlled respiratory rates on arterial blood gases (ABG) and end-tidal CO₂ (ETCO₂) levels during elective laparoscopic surgeries. It was carried out in the operating rooms of Darwish Nazzal Governmental Hospital, Qalqilia, Palestine, from June 2023 to January 2024.\u003c/p\u003e\u003cp\u003e\u003cb\u003eSample Size\u003c/b\u003e\u003c/p\u003e\u003cp\u003eA total of 60 adult patients undergoing elective laparoscopic surgery were included. Participants were conveniently sampled and divided into two groups based on ventilator settings: RR14 (n\u0026thinsp;=\u0026thinsp;30) and RR20 (n\u0026thinsp;=\u0026thinsp;30). The sample size was determined using a standard formula considering prior literature, aiming for 80% power to detect clinically relevant differences.\u003c/p\u003e\u003cp\u003e\u003cb\u003eInclusion and Exclusion Criteria\u003c/b\u003e\u003c/p\u003e\u003cp\u003eEligible participants were adults aged 18\u0026ndash;60 years, classified as ASA I or II, and scheduled for laparoscopic cholecystectomy or appendectomy under general anesthesia. Patients were excluded if they had respiratory or cardiac diseases, liver or kidney dysfunction, pregnancy, BMI\u0026thinsp;\u0026ge;\u0026thinsp;30 kg/m\u0026sup2;, or were on medications affecting respiratory or cardiovascular function.\u003c/p\u003e\u003cp\u003e\u003cb\u003eData Collection\u003c/b\u003e\u003c/p\u003e\u003cp\u003e Following ethical approval and patient consent, demographic and clinical data were recorded. An arterial line was placed for ABG sampling. ETCO₂, ABG parameters, vital signs, and peak airway pressure were measured at baseline, 15 minutes after insufflation, and post-disinflation. Surgery duration and intra-abdominal pressure were also documented.\u003c/p\u003e\u003cdiv id=\"Sec2\" class=\"Section2\"\u003e\u003ch2\u003eData Analysis\u003c/h2\u003e\u003cp\u003eStatistical analysis was performed using SPSS version 23. Descriptive statistics, Chi-square, independent and paired t-tests, repeated measures ANOVA, and Pearson correlations were used. A significance level of p\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was applied.\u003c/p\u003e\u003cp\u003e\u003cb\u003eEthical Considerations\u003c/b\u003e\u003c/p\u003e\u003cp\u003eEthical approval was obtained from An-Najah National University (Ref: Mas. July. 2023.3) and the Palestinian Ministry of Health. Written informed consent was secured from all participants, with confidentiality and voluntary participation fully respected.\u003c/p\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 60 adult patients undergoing elective laparoscopic surgery were included in this study. Participants were randomly allocated into two groups based on intraoperative respiratory rate settings: the RR14 group (n\u0026thinsp;=\u0026thinsp;30) and the RR20 group (n\u0026thinsp;=\u0026thinsp;30). The overall sample consisted of 22 males (36.7%) and 38 females (63.3%), with a mean age of 36 years, mean height of 170 cm, and mean weight of 67 kg. The majority of patients (86.7%) underwent laparoscopic cholecystectomy, while the remaining 13.3% underwent laparoscopic appendectomy. Approximately 33.3% of participants had a positive smoking history, and all patients had no prior medical history. No statistically significant differences were found between the two groups regarding baseline demographic characteristics (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05).\u003c/p\u003e\u003cp\u003e\u003cb\u003eEnd-Tidal CO₂ (ETCO₂) Levels\u003c/b\u003e\u003c/p\u003e\u003cp\u003eComparative analysis of ETCO₂ levels revealed statistically significant differences between the two respiratory rate groups at all surgical phases (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Prior to insufflation, the RR14 group demonstrated significantly higher ETCO₂ levels (Mean\u0026thinsp;=\u0026thinsp;35.87) compared to the RR20 group (Mean\u0026thinsp;=\u0026thinsp;33.97; p\u0026thinsp;=\u0026thinsp;0.006). During insufflation (15 minutes after CO₂ insufflation), ETCO₂ further increased in both groups, but remained significantly higher in the RR14 group (Mean\u0026thinsp;=\u0026thinsp;40.67) than in the RR20 group (Mean\u0026thinsp;=\u0026thinsp;36.63; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). After CO₂ venting (disinflation), the RR14 group again showed significantly higher ETCO₂ values (Mean\u0026thinsp;=\u0026thinsp;38.7) versus the RR20 group (Mean\u0026thinsp;=\u0026thinsp;34.03; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) (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\u003eComparisons between the two respiratory rate groups in ETCO₂ and ABG values during insufflation (n\u0026thinsp;=\u0026thinsp;60)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\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\u003eRR14 (n\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eRR20 (n\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eTotal (N\u0026thinsp;=\u0026thinsp;60)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eETCO₂ (mmHg)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e40.67\u0026thinsp;\u0026plusmn;\u0026thinsp;3.53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e36.63\u0026thinsp;\u0026plusmn;\u0026thinsp;2.59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e38.65\u0026thinsp;\u0026plusmn;\u0026thinsp;3.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003epH\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e7.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e7.37\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e7.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.008\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePaCO₂ (mmHg)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e44.08\u0026thinsp;\u0026plusmn;\u0026thinsp;4.27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e41.28\u0026thinsp;\u0026plusmn;\u0026thinsp;2.88\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e42.68\u0026thinsp;\u0026plusmn;\u0026thinsp;3.88\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.004\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eHCO₃ (mmol/L)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e23.89\u0026thinsp;\u0026plusmn;\u0026thinsp;1.01\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e24.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.74\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e\u003cp\u003e24.04\u0026thinsp;\u0026plusmn;\u0026thinsp;0.89\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.185\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eNote: Data are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD. Statistical significance tested with independent samples t-test.\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\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\u003eChanges in ETCO₂, ABG Values, and Peak Airway Pressure Across Surgical Phases (N\u0026thinsp;=\u0026thinsp;60)\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\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\u003eBefore Insufflation\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eDuring Insufflation\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAfter CO₂ Venting\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eETCO₂ (mmHg)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e34.92\u0026thinsp;\u0026plusmn;\u0026thinsp;2.71\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e38.65\u0026thinsp;\u0026plusmn;\u0026thinsp;3.68\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e36.37\u0026thinsp;\u0026plusmn;\u0026thinsp;3.47\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003epH\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e7.39\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e7.36\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026ndash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePaCO₂ (mmHg)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e38.84\u0026thinsp;\u0026plusmn;\u0026thinsp;2.77\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e42.68\u0026thinsp;\u0026plusmn;\u0026thinsp;3.88\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026ndash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePaO₂ (mmHg)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e83.96\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e90.22\u0026thinsp;\u0026plusmn;\u0026thinsp;4.23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026ndash;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003ePeak Airway Pressure (cmH₂O)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e\u003cp\u003e13.87\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e\u003cp\u003e23.48\u0026thinsp;\u0026plusmn;\u0026thinsp;3.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e17.09\u0026thinsp;\u0026plusmn;\u0026thinsp;2.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003e\u003cem\u003eNote: Repeated measures ANOVA used for comparisons. Values represent mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD.\u003c/em\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eArterial Blood Gas (ABG) Parameters\u003c/b\u003e\u003c/p\u003e\u003cp\u003eNo significant differences were observed between the two groups in ABG parameters before insufflation (p\u0026thinsp;\u0026gt;\u0026thinsp;0.05). However, during insufflation, significant group differences emerged. The RR14 group had lower pH values (Mean\u0026thinsp;=\u0026thinsp;7.36) compared to the RR20 group (Mean\u0026thinsp;=\u0026thinsp;7.37; p\u0026thinsp;=\u0026thinsp;0.008) and higher PaCO₂ levels (44.08 vs. 41.28 mmHg; p\u0026thinsp;=\u0026thinsp;0.004). No significant differences were noted in PaO₂ and HCO₃⁻ values between groups during this phase.\u003c/p\u003e\u003cp\u003ePaired comparisons before and during insufflation across the entire sample showed significant physiological changes. pH levels declined significantly from 7.39 to 7.36 (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), while PaCO₂ increased from 38.84 to 42.68 mmHg (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). PaO₂ significantly increased (83.96 to 90.22 mmHg; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and HCO₃⁻ slightly decreased (24.29 to 24.04 mmol/L; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), suggesting mild respiratory acidosis during insufflation.\u003c/p\u003e\u003cp\u003e\u003cb\u003eVital Signs and Peak Airway Pressure\u003c/b\u003e\u003c/p\u003e\u003cp\u003ePost-hoc pairwise comparisons showed significant changes in vital signs across surgical phases. Diastolic blood pressure increased during insufflation (Mean\u0026thinsp;=\u0026thinsp;79.85 mmHg), then decreased post-disinflation (Mean\u0026thinsp;=\u0026thinsp;75.8 mmHg; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Heart rate also increased significantly during insufflation (Mean\u0026thinsp;=\u0026thinsp;83.63 bpm) compared to pre- (78.9 bpm) and post-insufflation (78.48 bpm) values (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Similarly, SpO₂ improved during insufflation (Mean\u0026thinsp;=\u0026thinsp;98.85%) compared to before (97.02%) and after (98.2%) insufflation (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003cp\u003ePeak airway pressure significantly increased during insufflation (Mean\u0026thinsp;=\u0026thinsp;23.48 cmH₂O), then decreased post-insufflation (Mean\u0026thinsp;=\u0026thinsp;17.09 cmH₂O) and was lowest before insufflation (Mean\u0026thinsp;=\u0026thinsp;13.87 cmH₂O), with all comparisons showing p\u0026thinsp;\u0026lt;\u0026thinsp;0.001.\u003c/p\u003e\u003cp\u003e\u003cb\u003eCorrelations with Procedure Duration and Intra-abdominal Pressure\u003c/b\u003e\u003c/p\u003e\u003cp\u003ePearson correlation analysis indicated that procedure duration had a significant positive correlation with ETCO₂ (r\u0026thinsp;=\u0026thinsp;0.376, p\u0026thinsp;=\u0026thinsp;0.003) and PaCO₂ (r\u0026thinsp;=\u0026thinsp;0.368, p\u0026thinsp;=\u0026thinsp;0.004), and a significant negative correlation with pH (r = -0.294, p\u0026thinsp;=\u0026thinsp;0.023). Intra-abdominal pressure also showed significant positive correlations with ETCO₂ (r\u0026thinsp;=\u0026thinsp;0.369, p\u0026thinsp;=\u0026thinsp;0.004) and PaCO₂ (r\u0026thinsp;=\u0026thinsp;0.481, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and a significant negative correlation with pH (r = -0.308, p\u0026thinsp;=\u0026thinsp;0.017). These findings indicate that longer procedures and higher intra-abdominal pressures are associated with greater CO₂ retention and acidosis.\u003c/p\u003e\u003cp\u003e\u003cb\u003eImpact of Smoking History\u003c/b\u003e\u003c/p\u003e\u003cp\u003ePatients with a history of smoking had significantly higher baseline ETCO₂ levels (Mean\u0026thinsp;=\u0026thinsp;37.7 vs. 33.53; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), lower pH (7.34 vs. 7.38; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001), lower PaO₂ (81.91 vs. 84.98 mmHg; p\u0026thinsp;=\u0026thinsp;0.003), and higher PaCO₂ (41.78 vs. 37.37 mmHg; p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) compared to non-smokers. This suggests a compromised baseline respiratory status among smokers.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study demonstrates that increasing the intraoperative respiratory rate from 14 to 20 breaths per minute during elective laparoscopic surgery significantly reduces ETCO₂ and PaCO₂ levels, while mitigating the degree of respiratory acidosis, as evidenced by higher intraoperative pH values in the RR20 group. These findings align with recent literature indicating that higher respiratory rates facilitate more effective CO₂ elimination during laparoscopic procedures, thereby reducing the risk of hypercapnia and acidosis [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The observed increases in ETCO₂, PaCO₂, and peak airway pressure during insufflation are consistent with established effects of pneumoperitoneum on respiratory mechanics and gas exchange [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Notably, the positive correlations between procedure duration, intra-abdominal pressure, and CO₂ retention reinforce the importance of individualized ventilatory strategies, particularly for longer or more complex surgeries [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The impact of smoking history on baseline respiratory parameters further highlights the need for tailored perioperative management in patients with compromised pulmonary function [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Future research should explore optimal ventilatory settings across diverse patient populations and surgical contexts, as well as the long-term clinical outcomes of intraoperative respiratory management [\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Clinically, these results support the adoption of higher respiratory rates during laparoscopic surgery to enhance intraoperative safety, especially in patients at risk for CO₂ retention or acid-base disturbances [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eBased on the findings of this study, it is recommended that higher intraoperative respiratory rates, such as 20 breaths per minute, be considered during elective laparoscopic surgeries to help maintain optimal end-tidal CO₂ and arterial blood gas levels, thereby reducing the risk of CO₂ retention and respiratory acidosis. Anesthesiologists should closely monitor ETCO₂ and ABG parameters, especially in cases with longer procedure durations or elevated intra-abdominal pressures. Special attention should be given to patients with a positive smoking history, as they may exhibit impaired baseline respiratory function and be more susceptible to ventilation-related complications. Tailoring ventilatory management to patient-specific risk factors and surgical variables may improve intraoperative physiological stability and reduce postoperative complications.\u003c/p\u003e\u003cp\u003e\u003cb\u003eLimitations\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis study has several limitations that should be considered when interpreting the findings. First, although the sample size of 60 patients was sufficient for detecting significant differences, a larger multicenter study would enhance the generalizability of the results. Second, the study design was observational and non-randomized, which may introduce selection bias or unmeasured confounding factors. Third, the respiratory rates were fixed at two discrete levels without individualized adjustments based on patient characteristics or real-time monitoring feedback, which may not reflect the complexity of clinical practice. Finally, postoperative outcomes such as recovery time, complications, or long-term respiratory function were not assessed, limiting the ability to evaluate the clinical significance of intraoperative physiological differences. Future research should aim to address these limitations and further investigate the long-term implications of intraoperative ventilatory strategies.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis comparative observational study demonstrates that respiratory rate significantly influences end-tidal CO₂ levels and arterial blood gas parameters in patients undergoing elective laparoscopic surgery. Patients ventilated at a lower respiratory rate (RR14) exhibited higher ETCO₂ and PaCO₂ levels and lower pH values during and after insufflation, indicating greater CO₂ retention and mild respiratory acidosis compared to those ventilated at RR20. Additionally, vital signs such as heart rate and diastolic blood pressure showed significant intraoperative changes, with peak airway pressure rising during insufflation and correlating with elevated CO₂ levels. Longer procedure duration and increased intra-abdominal pressure were both associated with worsened gas exchange and acidosis. Furthermore, smoking history was linked to impaired baseline respiratory function, reflected in higher ETCO₂ and PaCO₂, and lower pH and PaO₂. These findings underscore the importance of tailoring intraoperative ventilatory strategies to minimize physiological disturbances, particularly in patients with risk factors such as prolonged surgery, high insufflation pressures, or a history of smoking.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003ctable border=\"0\" cellspacing=\"3\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eAbbreviation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003e\u003cstrong\u003eFull Term\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eABG\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eArterial Blood Gas\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eASA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eAmerican Society of Anesthesiologists\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eBMI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eBody Mass Index\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eCO₂\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eCarbon Dioxide\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eDBP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eDiastolic Blood Pressure\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eETCO₂\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eEnd-Tidal Carbon Dioxide\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eHR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eHeart Rate\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eHCO₃\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eBicarbonate\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eIRB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eInstitutional Review Board\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003ePaCO₂\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ePartial Pressure of Carbon Dioxide in Arterial Blood\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003ePaO₂\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ePartial Pressure of Oxygen in Arterial Blood\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eProbability Value (Statistical Significance)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eRR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eRespiratory Rate\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eRR14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eRespiratory Rate 14 breaths/min group\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eRR20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eRespiratory Rate 20 breaths/min group\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eSBP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eSystolic Blood Pressure\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eSD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eStandard Deviation\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eSPSS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eStatistical Package for the Social Sciences\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eSpO₂\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ePeripheral Oxygen Saturation\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Institutional Review Board\u0026nbsp;at An-Najah National University approved the research, and permission was obtained from the hospital. This study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. All methods were performed in accordance with the relevant guidelines and regulations sectors.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to participate\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from all participants after providing a full explanation of the study's purpose, procedures, and their rights as participants. Confidentiality and anonymity were strictly maintained. Participants were assured that their responses would be used solely for research purposes and that they could withdraw from the study at any time without any consequences. Additionally, formal requests for study approval were submitted and granted by the administrations of the participating hospitals, ensuring full institutional support and transparency.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon a reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial registration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eClinical trial number: not applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to thank An-Najah National University (www.najah.edu) for the technical support provided to publish the present manuscript\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eM.H., N.S. I.G, A. A (Ahmad Ayed), M.D and M.S and A.A (Aidah Alkaissi). conceived and planned the experiments and performed the measurements, I.G, \u0026nbsp;R.Z., M.H and M.S. were involved in planning and supervised the work, B.H, S.Q, R.Z, B.S, A.B and M.S aided in interpreting the results and worked on the manuscript. F.H, E.A, J.Q, I.T and M.S final draft editing. All authors discussed the results and commented on the manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eManangi M, Gangadharaiah R, Chikkanayakanahalli S, Naik M, Jayappa AB. A Study on Effects of Leaking Carbon Dioxide Gas on Surgeons during Laparoscopic Surgeries. World J Laparosc Surg DVD 2021.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMasum A, Kalam F, Alam M. Respiratory Changes under Spinal Anaesthesia for Laparoscopic Gynaecological Procedures- a comparison with General Anaesthesia. J Bangladesh Soc Anaesthesiologists 2021.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKajiwara M, Nakashima R, Yoshimura F, Hasegawa S. Impact of AirSeal\u0026reg; insufflation system on respiratory and circulatory dynamics during laparoscopic abdominal surgery. Updates Surg. 2022;74:2003\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePan X, Wang D. Effect of different positive end-expiratory pressure levels in patients undergoing laparoscopic cholecystectomy under general anesthesia. Pakistan J Med Sci. 2025;41:719\u0026ndash;23.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eIwasaka H, Miyakawa H, Yamamoto H, Kitano T, Taniguchi K, Honda N. Respiratory mechanics and arterial blood gases during and after laparoscopic cholecystectomy. Can J Anaesth = J canadien d'anesthesie. 1997;43 2:129\u0026ndash;33.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJo Y, Kim J, Park C, Chang Y, Kwak H. The Effect of Ventilation Strategy on Arterial and Cerebral Oxygenation During Laparoscopic Bariatric Surgery. Obes Surg. 2016;26:339\u0026ndash;44.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYessenbayeva G, Meyerbekova A, Kim S, Zhumabayev M, Berdiyarova G, Shalekenov S, Zharlyganova D, Mukatova I, Yukhnevich Y, Klyuyev D et al. Impact of a positive end-expiratory pressure on oxygenation, respiratory compliance, and hemodynamics in obese patients undergoing laparoscopic surgery in reverse Trendelenburg position: a systematic review and meta-analysis of randomized controlled trials. BMC Anesthesiol 2025, 25.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYildiz A, Kilinc G, Sungurtekin H, Karaduman S, Birsen O. Impact of positive end-expiratory pressure with alveolar recruitment maneuver on respiratory and oxygenation parameters of patients during laparoscopic bariatric surgery. Eur Rev Med Pharmacol Sci. 2022;26 24:9170\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eXie P, Li Z, Tian Z. The optimal combination of mechanical ventilator parameters under general anesthesia in obese patients undergoing laparoscopic surgery. J Clin Anesth. 2016;34:290\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eVasudevan V. Abstract No.: ABS3339: Effects of volume controlled and pressure controlled volume guaranteed modes of ventilation on respiratory dynamics during laparoscopic surgery in children: A prospective observational study. Indian J Anaesth 2022, 66.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Laparoscopic surgery, end-tidal CO₂, arterial blood gases, respiratory rate, ventilation, CO₂ insufflation, intra-abdominal pressure","lastPublishedDoi":"10.21203/rs.3.rs-7242284/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7242284/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eLaparoscopic surgery requires CO₂ insufflation to create pneumoperitoneum, which may lead to significant physiological changes, particularly in respiratory parameters such as end-tidal CO₂ (ETCO₂) and arterial blood gases (ABG). Intraoperative ventilation strategies, particularly respiratory rate, can influence CO₂ retention and acid-base balance. However, comparative evidence regarding optimal respiratory rates during laparoscopy remains limited.\u003c/p\u003e\u003ch2\u003eAim\u003c/h2\u003e\u003cp\u003eTo compare the effects of two controlled respiratory rates (14 vs. 20 breaths per minute) on ETCO₂ and ABG parameters in adult patients undergoing elective laparoscopic surgery.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eThis prospective comparative study included 60 adult patients scheduled for elective laparoscopic surgeries at Darwish Nazzal Governmental Hospital, Palestine, between June 2023 and January 2024. Patients were assigned to either the RR14 or RR20 group (30 patients each). ETCO₂, ABG parameters, vital signs, and peak airway pressure were measured at baseline, 15 minutes after insufflation, and post-disinflation. Data were analyzed using SPSS v23 with independent t-tests, repeated measures ANOVA, and Pearson correlation tests.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThe RR14 group showed significantly higher ETCO₂ levels than the RR20 group at all time points (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). During insufflation, the RR14 group had higher PaCO₂ (44.08 vs. 41.28 mmHg; p\u0026thinsp;=\u0026thinsp;0.004) and lower pH (7.36 vs. 7.37; p\u0026thinsp;=\u0026thinsp;0.008). Longer procedure duration and higher intra-abdominal pressure were positively correlated with elevated ETCO₂ and PaCO₂ and negatively with pH. Smoking history was associated with impaired baseline respiratory values (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eLower respiratory rates during laparoscopic surgery are associated with increased CO₂ retention and mild respiratory acidosis. Tailoring respiratory rate settings based on patient characteristics and intraoperative conditions may enhance physiological stability and safety.\u003c/p\u003e","manuscriptTitle":"The effect of controlled respiratory rate on end-tidal co₂, arterial blood gases, and hemodynamic parameters during elective laparoscopic surgery: a comparative observational study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-21 18:21:30","doi":"10.21203/rs.3.rs-7242284/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"d9602da9-9b57-4cd5-9aa2-e9fac9dc54af","owner":[],"postedDate":"August 21st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-05T11:38:52+00:00","versionOfRecord":[],"versionCreatedAt":"2025-08-21 18:21:30","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7242284","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7242284","identity":"rs-7242284","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}