Usefulness of Simultaneous Measurement of Brain and Muscle rSO2 (Regional Oxygen Saturation) in Shock Patients: a Report of Three Cases

Usefulness of Simultaneous Measurement of Brain and Muscle rSO2 (Regional Oxygen Saturation) in Shock Patients: a Report of Three Cases | 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 Help Center Sign In Submit a Preprint Cite Share Download PDF Case report Usefulness of Simultaneous Measurement of Brain and Muscle rSO 2 (Regional Oxygen Saturation) in Shock Patients: a Report of Three Cases Arisa Muratsu, Tomoya Hirose, Mitsuo Ohnishi, Jotaro Tachino, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-570750/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 In the field of emergency medical care, we often experience a situation in which we cannot measure pulse oximetric saturation (SpO₂) or blood pressure due to circulatory failure associated with shock. However, as we can measure rSO₂ values of the brain even in patients with shock, we hypothesized that we could evaluate the oxygen supply-demand balance between brain and muscle tissue by simultaneously measuring regional oxygen saturation (rSO₂) values of the brain and muscle tissue of patients with shock. Case presentation We attached a TOS-OR rSO₂ monitor (TOSTEC CO., Tokyo, Japan) to 10 healthy volunteers and measured the rSO₂ values of their brain and muscle for 3 minutes. The rSO₂ values of their brain cerebral regional oxygen saturation (crSO₂) and muscle regional oxygen saturation (mrSO₂) were 77.6±1.6% and 76.2±1.3% (mean ± SD). There was little difference between crSO₂ and mrSO₂ (cerebro-musculoskeletal difference in regional saturation of oxygen; c-mDrSO₂). However, there were discernible amount of c-mDrSO₂ in three cases with shock, Case 1 showed a prolonged shock state due to septic shock caused by bacterial pneumonia. Her crSO₂ values was always higher than her mrSO₂ value, and there was a c-mDrSO₂. Case 2 showed a decrease in mean arterial pressure (MAP) with the development of septic shock caused by intestinal perforation. His crSO₂ value was higher than that of his mrSO₂, and c-mDrSO₂ increased with the decrease of his MAP. Case 3 had a low MAP due to hemorrhagic shock caused by postpartum hemorrhage. Her crSO₂ value was higher than that of her mrSO₂ and a c-mDrSO₂ was present. After resuscitation, the c-mDrSO₂ decreased with the increase in her blood pressure. Conclusion We evaluated the usefulness of simultaneous measurement of crSO₂ and mrSO₂ as an objective and non-invasive method in shock management. Even if SpO₂ or blood pressure could not be measured due to circulatory failure associated with shock, it was possible to measure the values of crSO₂ and mrSO₂, which changed in real time with fluctuation of the blood pressure. Unlike previous monitoring devices, the rSO₂ monitor may continuously and clearly reflect the changes in local oxygen supply-demand balance. Critical Care & Emergency Medicine Near-infrared spectroscopy shock rSO2 monitor muscle rSO2 brain rSO2 Figures Figure 1 Figure 2 Background In the field of emergency medical care, we often experience a situation in which we cannnot measure pulse oximetric saturation (SpO 2 ) or blood pressure due to circulatory failure associated with shock. Regional oxygen saturation (rSO₂) is known as an indicator of changes in the local oxygen supply-demand balance [ 1 ]. Particularly, near-infrared spectroscopy which measures rSO₂ in the brain can noninvasively measure the proportion of oxygenated hemoglobin at the site to be monitored in real-time using the difference in the absorption of near-infrared rays from oxygenated hemoglobin and reduced hemoglobin in the blood [ 2 ]. This method can measure oxygen saturation in a non-pulsatile flow environment and therefore can be used in patients with circulatory failure [ 3 ] or after cardiac arrest [ 4 ]. To our knowledge, however, no previous study has simultaneously evaluated the oxygen supply-demand balance between central such as the brain and peripheral such as the muscle tissue in a noninvasive and real-time manner in patients with shock. We hypothesized that we could evaluate the oxygen supply-demand balance between brain and muscle tissue by simultaneously measuring rSO₂ values of the brain and muscle tissues of patients in shock using an rSO₂ monitor (TOS-OR; TOSTEC CO., Tokyo Japan) [ 5 , 6 ]. The study protocol was approved by the Institutional Review Board of Osaka University (approval no. 19540), which waived the need to obtain patient written informed consent because this was a noninvasive observational study. Here, we show the rSO₂ values of the brain and muscle tissues of healthy volunteers and of three patients in shock in whom we preliminarily evaluated the rSO₂ values of the brain and muscle tissues during their resuscitation. We discuss the potential effectiveness of simultaneously assessing brain and muscle rSO₂ in shock management. Case Presentations Brain and muscle rSO 2 in healthy volunteers We attached the sensors of the rSO₂ monitor to the forehead and the dorsal lower leg of 10 healthy volunteers lying in the supine position and measured rSO₂ values at these locations for 3 minutes (Fig. 1 ). The reason for choosing the dorsal lower leg as the measurement site was because it was easy to attach the sensor when clothes are worn and measurement was less affected by body hair or physical constitution. When the sensor of the rSO₂ monitor was placed on the dorsal side of the lower leg, we confirmed by ultrasound that the depth from the skin surface to the muscle being measured by the sensor was 20 to 25 mm. The rSO₂ values of the volunteers’ brain (cerebral regional oxygen saturation [crSO₂]) and muscle (muscle regional oxygen saturation [mrSO₂]) measurements were 77.6 ± 1.6% and 76.2 ± 1.3% (mean ± SD), respectively. There was little difference in cerebro-muscular regional saturation of oxygen (c-mDrSO₂) as indicated by the small difference between the crSO₂ and mrSO₂ values (Table 1 ). Table 1 Values of cerebral regional oxygen saturation (crSO 2 ) and muscle regional oxygen saturation (mrSO 2 ) in healthy volunteers Patient No. Age (years) Sex sBP (mmHg) dBP (mmHg) MAP (mmHg) crSO 2 (%) mrSO 2 (%) mean SD mean SD 1 29 M 121 84 96 78.6 0.3 74.5 0.3 2 28 M 150 100 117 81.3 0.5 76.2 0.5 3 43 M 156 115 129 79.2 0.4 76.9 0.4 4 29 M 109 63 78 76.3 1.2 76.3 1.3 5 39 M 124 80 95 77.7 0.8 76.9 0.7 6 33 F 109 75 86 77.9 0.7 77.0 0.7 7 32 F 107 71 83 75.1 0.4 77.1 0.4 8 29 M 102 70 81 77.2 0.8 78.1 1.1 9 34 M 153 82 106 77.0 0.9 73.4 1.0 10 32 M 117 74 88 77.0 0.3 75.3 0.2 No . number, M male, F female, sBP systolic blood pressure, dBP diastolic blood pressure, MAP mean arterial pressure, SD standard deviation Shock case 1 A 56-year-old woman was admitted to our hospital with respiratory distress and malaise. On arrival, her heart rate was 145 beats per minute, and we then could not palpate her radial artery pulse or measure SpO₂ because of her low blood pressure. We attached the sensors of the rSO₂ monitor to her forehead and dorsal lower leg and measured the rSO₂ values of her brain and muscle. Both values could be measured, and the value of crSO₂ was higher than that of mrSO₂. We diagnosed her condition as septic shock caused by bacterial pneumonia and treated her with fluid resuscitation immediately. Her mean arterial pressure (MAP) continued to be low, but after 1 hour we could measure a blood pressure by a noninvasive method. Meanwhile, the value of her crSO₂ remained higher than that of her mrSO₂. Although this patient’s shock state was prolonged by septic shock caused by bacterial pneumonia, the value of her crSO₂ was always higher than that of mrSO₂, and the c-mDrSO₂ was large (Fig. 2 a). Shock case 2 An 82-year-old man was transferred to our hospital with a diagnosis of septic shock caused by intestinal perforation. On admission, his blood pressure was 136/52 mmHg (MAP 73 mmHg), and his heart rate was 136 beats per minute under administration of noradrenaline and lactated ringers solution We urgently performed partial resection of the intestine on the day of transfer. Just after the operation, his MAP was over 65 mmHg with the administration of noradrenaline, and his crSO₂ value was about the same as his mrSO₂ value. However, his MAP gradually decreased to below 60 mmHg at 1.6 hours after the operation. Meanwhile, his crSO₂ value remained higher than that of his mrSO₂ value, and c-mDrSO₂ increased with the decrease of the MAP. His MAP did not decrease any further by 1.8 hours after the operation, and the c-mDrSO₂ stabilized. This patient showed a decrease in his MAP with the development of septic shock caused by intestinal perforation. His crSO₂ value remained higher than that of his mrSO₂, and the c-mDrSO₂ increased in tandem with the decrease of his MAP (Fig. 2 b). Shock case 3 A 38-year-old woman was transferred to our hospital with a diagnosis of hemorrhagic shock following postpartum hemorrhage. On admission, her blood pressure was 74/40 mmHg (MAP 38 mmHg), and her heart rate was 86 beats per minute We attached the TOS-OR rSO₂ sensor to her forehead and dorsal upper arm on admission and measured the values of crSO₂ and mrSO₂. The crSO₂ value was higher than that of her mrSO₂ value, and there was a c-mDrSO₂. The bleeding from her uterus persisted, and her hemoglobin on admission was 6.5 g/dL. We began the administration of red blood cells at admission and her MAP gradually increased. When her MAP rose above 85 mmHg, her crSO₂ value became about the same as that of her mrSO₂. In this patient with a low MAP due to hemorrhagic shock following postpartum hemorrhage, the value of her crSO₂ was higher than that of her mrSO₂ and a c-mDrSO₂ was present. After her blood pressure began to increase, the c-mDrSO₂ became much smaller (Fig. 2 c). Discussion And Conclusion We revealed the following three points by simultaneously measuring the values of crSO₂ and mrSO₂. First, the value of crSO₂ is almost the same as that of mrSO₂ in healthy volunteers. Second, even if SpO₂ or blood pressure cannot be measured due to circulatory failure associated with shock, it is possible to measure crSO₂ and mrSO₂. Third, in the shock state, there is a difference in rSO₂ values between brain and muscle, and the value of crSO₂ is higher than that of mrSO₂. The present study is the first report, to our knowledge, to suggest that measurement of crSO₂ and mrSO₂ in shock patients may continuously and clearly reflect the oxygen supply-demand balance. There are three stages of shock: stage I (compensatory shock), stage II (decompensatory shock), and stage III (irreversible shock). Particularly, in the early phase of stage I, blood flow to the organs decreases, but blood flow in the major organs manages to be maintained by the physiological response generated to recover blood circulation [ 7 ]. Previous studies assessed blood flow to the organs in shock patients by placement of an intravascular catheter [ 8 ] or by pulse-wave Doppler [ 9 , 10 ]. In contrast, we used the rSO₂ monitor as the tool to measure organ blood flow continuously and noninvasively. Among the studies of patients in shock, there are reports that the value of crSO₂ is low when the MAP is low but that it increases with the increase in MAP [ 3 , 11 – 13 ]. Other reports on mrSO₂ showed a similar tendency to that of crSO₂ [ 14 – 16 ]. In this first report of the simultaneous measurement and assessment of the values of crSO₂ and mrSO₂ in shock patients, we illustrated Fig. 2 d the expected change of crSO₂ and mrSO₂ as the MAP changes. In the case of a stable MAP, the values of crSO₂ and mrSO₂ are almost equal, and the c-mDrSO₂ is small (C). In the case of decreased MAP, tissue blood flow to the non-major organs decreases, and the value of mrSO₂ also decreases (B). For this reason, the value of crSO₂ is maintained at a higher value than that of rSO₂ (B), and c-mDrSO₂ increases with the decrease in MAP. In the case of remarkable hypovolemia, blood flow to the brain decreases, and the value of crSO₂ also decreases. Thus, the values of crSO₂ and mrSO₂ are almost equal, and thus, c-mDrSO₂ decreases (A) When we apply the diagram to our study, the case of healthy volunteers applies to (C). Case 1 shows that in patients with septic shock, MAP, crSO₂, and mrSO₂ change from (A) to (B) with the administration of fluid resuscitation and vasopressors. Case 2 shows that MAP, crSO₂, and mrSO₂ of the patients with septic shock change from (C) to (B). Case 3 shows that in patients with hypovolemic shock, MAP, crSO₂, and mrSO₂ change from (B) to (C) with the administration of red blood cells. The candidates for appropriately targeting MAP are those showing a change from (C) to (B) or from (A) to (B) to preserve major organ blood flow. We consider that stage I of the three stages of shock matches with (C), stage II matches with (B), and stage III matches with (A). Our study showed that even if SpO₂ or blood pressure cannot be measured due to circulatory failure associated with shock, it is still possible to measure the values of crSO₂ and mrSO₂. Besides, because the values change in real time with fluctuation of the blood pressure, unlike with previous monitoring devices, the rSO₂ monitor may continuously and clearly reflect the changes in the local oxygen supply-demand balance. Further, simultaneous measurement of crSO₂ and mrSO₂ rather than either crSO₂ or mrSO₂ alone may be helpful as a real-time method for evaluating therapeutic effect. A limitation of this study is the presence of selection bias associated with the choice of case reports used. We are continuing to accumulate additional cases and examining whether the simultaneous measurement of crSO₂ and mrSO₂ might be a useful method to evaluate adequate blood pressure in shock management. In conclusion, we evaluated the usefulness of the simultaneous measurement of crSO₂ and mrSO₂ and found that it might be an objective and noninvasive method of evaluating blood pressure management in shock patients. Abbreviations c-mDrSO₂: difference in cerebro-musculoskeletal regional saturation of oxygen; crSO 2 : cerebral regional oxygen saturation; MAP: mean arterial pressure; mrSO 2 : muscle regional oxygen saturation; rSO₂: regional oxygen saturation; SpO₂: pulse oximetric saturation. Declarations Ethics approvals and consent to participate The study protocol was approved by the Institutional Review Board of Osaka University (Approval Number: 19540), which waived the need to obtain patient written informed consent because of the observational nature of the study. Consent for publication The need to obtain patient written informed consent was waived because of the observational nature of the study. Availability of data and materials Not applicable. Competing interests The authors declare that they have no competing interests. Funding This work received research funding from ZENKYOREN (National Mutual Insurance Federation of Agricultural Cooperatives). Authors’ contributions A.M., R.T., and M.O. conceived the study, and participated in its design. A.M., S.N., and J.T. collected and generated the data. A.M. wrote the first draft. T.H helped to draft the manuscript. All of the authors read and approved the final manuscript. Acknowledgments We gratefully acknowledge the devoted cooperation of the Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine. References Crookes BA, Cohn SM, Bloch S, Amortegui J, Manning R, Li P, Can near-infrared spectroscopy identify the severity of shock in trauma patients?. J Trauma. 2005;58(4):806-816. Jöbsis FF. Noninvasive, infrared monitoring of cerebral and myocardial oxygen sufficiency and circulatory parameters. Science. 1977;198:1264–7. Varis E, Pettilä V, Wilkman E. Near-infrared spectroscopy in adult circulatory shock: a systematic review. J Intensive Care Med. 2020;35:943–62. Takegawa R, Shiozaki T, Ogawa Y, Hirose T, Mori N, Ohnishi M, et al. Usefulness of cerebral rSO(2) monitoring during CPR to predict the probability of return of spontaneous circulation. Resuscitation. 2019;139:201–7. Ehara N, Hirose T, Shiozaki T, Wakai A, Nishimura T, Mori N, et al. 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Thooft A, Favory R, Salgado DR, Taccone FS, Donadello K, De Backer D, et al. Effects of changes in arterial pressure on organ perfusion during septic shock. Crit Care. 2011;15:R222. McKinley BA, Marvin RG, Cocanour CS, Moore FA. Tissue hemoglobin O2 saturation during resuscitation of traumatic shock monitored using near infrared spectrometry. J Trauma. 2000;48:637–42. 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. 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Also discoverable on Platform About Our Team In Review Editorial Policies 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-570750","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case report","associatedPublications":[],"authors":[{"id":30454552,"identity":"efca1c22-b996-4d23-8328-104571d797fb","order_by":0,"name":"Arisa 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14:43:26","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":210794,"visible":true,"origin":"","legend":"Photographs show the rSO₂ monitor and sensors and rSO₂ measurement in a mock patient. (a) The rSO₂ monitor (TOS-OR; TOSTEC CO., Tokyo Japan) can noninvasively measure the proportion of oxygenated hemoglobin in real-time at the site to be monitored. This monitor has two sensors that are ordinarily attached to the left and right sides of the forehead. (b) In our study, we separated the sensors and attached one to the forehead and the other to the dorsal lower leg or dorsal upper arm to measure the rSO₂ values of the patient’s brain and muscle, respectively. The sensors are shown attached to the forehead and dorsal lower leg of the mock patient.","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-570750/v1/1902883bd660c8c8787c8f90.jpg"},{"id":9941309,"identity":"96b51eff-4415-4694-af3e-4a7f3fbcc6d1","added_by":"auto","created_at":"2021-06-03 14:43:26","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":153514,"visible":true,"origin":"","legend":"Serial changes of MAP, crSO₂, mrSO₂, and c-mDrSO₂ in three patients with shock. (a) Case 1: Septic shock caused by bacterial pneumonia. (b) Case 2: Septic shock caused by bowel perforation. (c) Case 3: Hypovolemic shock caused by obstetric bleeding. d) A diagram of the expected crSO₂ and mrSO₂ waveforms. [C] In the case of stable MAP, the values of crSO₂ and mrSO₂ are almost equal and the c-mDrSO₂ is small. [B] With a decreasing MAP, the value of mrSO₂ decreases and that of c-mDrSO₂ increases. [A] In the case of remarkable hypovolemia, the values of both mrSO₂ and crSO₂ decrease, and the c-mDrSO₂ also decreases. crSO₂ cerebral regional oxygen saturation, mrSO₂ muscle regional oxygen saturation, MAP mean arterial pressure, c-mDrSO₂ difference in cerebro-musculoskeletal regional saturation of oxygen.","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-570750/v1/d8f89e88812b2ca312d82a4a.jpg"},{"id":15673399,"identity":"6503de1b-e31a-44bc-9d5c-c79df2b5921a","added_by":"auto","created_at":"2021-11-18 14:17:46","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":478507,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-570750/v1/65593939-0e8f-455f-ad84-389f3c9fb0a7.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003eUsefulness of Simultaneous Measurement of Brain and Muscle rSO\u003csub\u003e2\u003c/sub\u003e (Regional Oxygen Saturation) in Shock Patients: a Report of Three Cases\u003c/p\u003e","fulltext":[{"header":"Background","content":" \u003cp\u003eIn the field of emergency medical care, we often experience a situation in which we cannnot measure pulse oximetric saturation (SpO\u003csub\u003e2\u003c/sub\u003e) or blood pressure due to circulatory failure associated with shock. Regional oxygen saturation (rSO₂) is known as an indicator of changes in the local oxygen supply-demand balance [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Particularly, near-infrared spectroscopy which measures rSO₂ in the brain can noninvasively measure the proportion of oxygenated hemoglobin at the site to be monitored in real-time using the difference in the absorption of near-infrared rays from oxygenated hemoglobin and reduced hemoglobin in the blood [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. This method can measure oxygen saturation in a non-pulsatile flow environment and therefore can be used in patients with circulatory failure [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] or after cardiac arrest [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. To our knowledge, however, no previous study has simultaneously evaluated the oxygen supply-demand balance between central such as the brain and peripheral such as the muscle tissue in a noninvasive and real-time manner in patients with shock.\u003c/p\u003e \u003cp\u003eWe hypothesized that we could evaluate the oxygen supply-demand balance between brain and muscle tissue by simultaneously measuring rSO₂ values of the brain and muscle tissues of patients in shock using an rSO₂ monitor (TOS-OR; TOSTEC CO., Tokyo Japan) [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. The study protocol was approved by the Institutional Review Board of Osaka University (approval no. 19540), which waived the need to obtain patient written informed consent because this was a noninvasive observational study.\u003c/p\u003e \u003cp\u003eHere, we show the rSO₂ values of the brain and muscle tissues of healthy volunteers and of three patients in shock in whom we preliminarily evaluated the rSO₂ values of the brain and muscle tissues during their resuscitation. We discuss the potential effectiveness of simultaneously assessing brain and muscle rSO₂ in shock management.\u003c/p\u003e "},{"header":"Case Presentations","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n\u003ch2\u003eBrain and muscle rSO\u003csub\u003e2\u003c/sub\u003e in healthy volunteers\u003c/h2\u003e\n\u003cp\u003eWe attached the sensors of the rSO₂ monitor to the forehead and the dorsal lower leg of 10 healthy volunteers lying in the supine position and measured rSO₂ values at these locations for 3 minutes (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). The reason for choosing the dorsal lower leg as the measurement site was because it was easy to attach the sensor when clothes are worn and measurement was less affected by body hair or physical constitution. When the sensor of the rSO₂ monitor was placed on the dorsal side of the lower leg, we confirmed by ultrasound that the depth from the skin surface to the muscle being measured by the sensor was 20 to 25 mm. The rSO₂ values of the volunteers\u0026rsquo; brain (cerebral regional oxygen saturation [crSO₂]) and muscle (muscle regional oxygen saturation [mrSO₂]) measurements were 77.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6% and 76.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3% (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD), respectively. There was little difference in cerebro-muscular regional saturation of oxygen (c-mDrSO₂) as indicated by the small difference between the crSO₂ and mrSO₂ values (Table\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003ctable id=\"Tab1\" border=\"1\"\u003e\u003ccaption\u003e\n\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n\u003cdiv class=\"CaptionContent\"\u003e\n\u003cp\u003eValues of cerebral regional oxygen saturation (crSO\u003csub\u003e2\u003c/sub\u003e) and muscle regional oxygen saturation (mrSO\u003csub\u003e2\u003c/sub\u003e) in healthy volunteers\u003c/p\u003e\n\u003c/div\u003e\n\u003c/caption\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth style=\"width: 81px;\" align=\"left\"\u003e\n\u003cp\u003ePatient\u003c/p\u003e\n\u003cp\u003eNo.\u003c/p\u003e\n\u003c/th\u003e\n\u003cth style=\"width: 83px;\" align=\"left\"\u003e\n\u003cp\u003eAge\u003c/p\u003e\n\u003cp\u003e(years)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth style=\"width: 43px;\" align=\"left\"\u003e\n\u003cp\u003eSex\u003c/p\u003e\n\u003c/th\u003e\n\u003cth style=\"width: 96px;\" align=\"left\"\u003e\n\u003cp\u003esBP\u003c/p\u003e\n\u003cp\u003e(mmHg)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth style=\"width: 96px;\" align=\"left\"\u003e\n\u003cp\u003edBP\u003c/p\u003e\n\u003cp\u003e(mmHg)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth style=\"width: 96px;\" align=\"left\"\u003e\n\u003cp\u003eMAP\u003c/p\u003e\n\u003cp\u003e(mmHg)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth style=\"width: 111px;\" colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003ecrSO\u003csub\u003e2\u003c/sub\u003e (%)\u003c/p\u003e\n\u003c/th\u003e\n\u003cth style=\"width: 121px;\" colspan=\"2\" align=\"left\"\u003e\n\u003cp\u003emrSO\u003csub\u003e2\u003c/sub\u003e (%)\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 81px;\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd style=\"width: 83px;\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd style=\"width: 43px;\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd style=\"width: 96px;\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd style=\"width: 96px;\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd style=\"width: 96px;\" align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd style=\"width: 68px;\" align=\"left\"\u003e\n\u003cp\u003emean\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 43px;\" align=\"left\"\u003e\n\u003cp\u003eSD\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 73px;\" align=\"left\"\u003e\n\u003cp\u003emean\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 48px;\" 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align=\"left\"\u003e\n\u003cp\u003e1.0\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 81px;\" align=\"left\"\u003e\n\u003cp\u003e10\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 83px;\" align=\"left\"\u003e\n\u003cp\u003e32\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 43px;\" align=\"left\"\u003e\n\u003cp\u003eM\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 96px;\" align=\"left\"\u003e\n\u003cp\u003e117\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 96px;\" align=\"left\"\u003e\n\u003cp\u003e74\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 96px;\" align=\"left\"\u003e\n\u003cp\u003e88\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 68px;\" align=\"left\"\u003e\n\u003cp\u003e77.0\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 43px;\" align=\"left\"\u003e\n\u003cp\u003e0.3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 73px;\" align=\"left\"\u003e\n\u003cp\u003e75.3\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd style=\"width: 48px;\" align=\"left\"\u003e\n\u003cp\u003e0.2\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"width: 727px;\" colspan=\"10\" align=\"left\"\u003e\n\u003cp\u003e\u003cem\u003eNo\u003c/em\u003e. number, \u003cem\u003eM\u003c/em\u003e male, \u003cem\u003eF\u003c/em\u003e female, \u003cem\u003esBP\u003c/em\u003e systolic blood pressure, \u003cem\u003edBP\u003c/em\u003e diastolic blood pressure, \u003cem\u003eMAP\u003c/em\u003e mean arterial pressure, \u003cem\u003eSD\u003c/em\u003e standard deviation\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n\u003ch2\u003eShock case 1\u003c/h2\u003e\n\u003cp\u003eA 56-year-old woman was admitted to our hospital with respiratory distress and malaise. On arrival, her heart rate was 145 beats per minute, and we then could not palpate her radial artery pulse or measure SpO₂ because of her low blood pressure. We attached the sensors of the rSO₂ monitor to her forehead and dorsal lower leg and measured the rSO₂ values of her brain and muscle. Both values could be measured, and the value of crSO₂ was higher than that of mrSO₂. We diagnosed her condition as septic shock caused by bacterial pneumonia and treated her with fluid resuscitation immediately. Her mean arterial pressure (MAP) continued to be low, but after 1 hour we could measure a blood pressure by a noninvasive method. Meanwhile, the value of her crSO₂ remained higher than that of her mrSO₂. Although this patient\u0026rsquo;s shock state was prolonged by septic shock caused by bacterial pneumonia, the value of her crSO₂ was always higher than that of mrSO₂, and the c-mDrSO₂ was large (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ea).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\n\u003ch2\u003eShock case 2\u003c/h2\u003e\n\u003cp\u003eAn 82-year-old man was transferred to our hospital with a diagnosis of septic shock caused by intestinal perforation. On admission, his blood pressure was 136/52 mmHg (MAP 73 mmHg), and his heart rate was 136 beats per minute under administration of noradrenaline and lactated ringers solution We urgently performed partial resection of the intestine on the day of transfer. Just after the operation, his MAP was over 65 mmHg with the administration of noradrenaline, and his crSO₂ value was about the same as his mrSO₂ value. However, his MAP gradually decreased to below 60 mmHg at 1.6 hours after the operation. Meanwhile, his crSO₂ value remained higher than that of his mrSO₂ value, and c-mDrSO₂ increased with the decrease of the MAP. His MAP did not decrease any further by 1.8 hours after the operation, and the c-mDrSO₂ stabilized. This patient showed a decrease in his MAP with the development of septic shock caused by intestinal perforation. His crSO₂ value remained higher than that of his mrSO₂, and the c-mDrSO₂ increased in tandem with the decrease of his MAP (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003eb).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\n\u003ch2\u003eShock case 3\u003c/h2\u003e\n\u003cp\u003eA 38-year-old woman was transferred to our hospital with a diagnosis of hemorrhagic shock following postpartum hemorrhage. On admission, her blood pressure was 74/40 mmHg (MAP 38 mmHg), and her heart rate was 86 beats per minute We attached the TOS-OR rSO₂ sensor to her forehead and dorsal upper arm on admission and measured the values of crSO₂ and mrSO₂. The crSO₂ value was higher than that of her mrSO₂ value, and there was a c-mDrSO₂. The bleeding from her uterus persisted, and her hemoglobin on admission was 6.5 g/dL. We began the administration of red blood cells at admission and her MAP gradually increased. When her MAP rose above 85 mmHg, her crSO₂ value became about the same as that of her mrSO₂. In this patient with a low MAP due to hemorrhagic shock following postpartum hemorrhage, the value of her crSO₂ was higher than that of her mrSO₂ and a c-mDrSO₂ was present. After her blood pressure began to increase, the c-mDrSO₂ became much smaller (Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ec).\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Discussion And Conclusion","content":"\u003cp\u003eWe revealed the following three points by simultaneously measuring the values of crSO₂ and mrSO₂. First, the value of crSO₂ is almost the same as that of mrSO₂ in healthy volunteers. Second, even if SpO₂ or blood pressure cannot be measured due to circulatory failure associated with shock, it is possible to measure crSO₂ and mrSO₂. Third, in the shock state, there is a difference in rSO₂ values between brain and muscle, and the value of crSO₂ is higher than that of mrSO₂. The present study is the first report, to our knowledge, to suggest that measurement of crSO₂ and mrSO₂ in shock patients may continuously and clearly reflect the oxygen supply-demand balance.\u003c/p\u003e\n\u003cp\u003eThere are three stages of shock: stage I (compensatory shock), stage II (decompensatory shock), and stage III (irreversible shock). Particularly, in the early phase of stage I, blood flow to the organs decreases, but blood flow in the major organs manages to be maintained by the physiological response generated to recover blood circulation [\u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e]. Previous studies assessed blood flow to the organs in shock patients by placement of an intravascular catheter [\u003cspan class=\"CitationRef\"\u003e8\u003c/span\u003e] or by pulse-wave Doppler [\u003cspan class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e]. In contrast, we used the rSO₂ monitor as the tool to measure organ blood flow continuously and noninvasively.\u003c/p\u003e\n\u003cp\u003eAmong the studies of patients in shock, there are reports that the value of crSO₂ is low when the MAP is low but that it increases with the increase in MAP [\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e]. Other reports on mrSO₂ showed a similar tendency to that of crSO₂ [\u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003eIn this first report of the simultaneous measurement and assessment of the values of crSO₂ and mrSO₂ in shock patients, we illustrated Fig.\u0026nbsp;\u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003ed the expected change of crSO₂ and mrSO₂ as the MAP changes. In the case of a stable MAP, the values of crSO₂ and mrSO₂ are almost equal, and the c-mDrSO₂ is small (C). In the case of decreased MAP, tissue blood flow to the non-major organs decreases, and the value of mrSO₂ also decreases (B). For this reason, the value of crSO₂ is maintained at a higher value than that of rSO₂ (B), and c-mDrSO₂ increases with the decrease in MAP. In the case of remarkable hypovolemia, blood flow to the brain decreases, and the value of crSO₂ also decreases. Thus, the values of crSO₂ and mrSO₂ are almost equal, and thus, c-mDrSO₂ decreases (A)\u003c/p\u003e\n\u003cp\u003eWhen we apply the diagram to our study, the case of healthy volunteers applies to (C). Case 1 shows that in patients with septic shock, MAP, crSO₂, and mrSO₂ change from (A) to (B) with the administration of fluid resuscitation and vasopressors. Case 2 shows that MAP, crSO₂, and mrSO₂ of the patients with septic shock change from (C) to (B). Case 3 shows that in patients with hypovolemic shock, MAP, crSO₂, and mrSO₂ change from (B) to (C) with the administration of red blood cells. The candidates for appropriately targeting MAP are those showing a change from (C) to (B) or from (A) to (B) to preserve major organ blood flow. We consider that stage I of the three stages of shock matches with (C), stage II matches with (B), and stage III matches with (A).\u003c/p\u003e\n\u003cp\u003eOur study showed that even if SpO₂ or blood pressure cannot be measured due to circulatory failure associated with shock, it is still possible to measure the values of crSO₂ and mrSO₂. Besides, because the values change in real time with fluctuation of the blood pressure, unlike with previous monitoring devices, the rSO₂ monitor may continuously and clearly reflect the changes in the local oxygen supply-demand balance. Further, simultaneous measurement of crSO₂ and mrSO₂ rather than either crSO₂ or mrSO₂ alone may be helpful as a real-time method for evaluating therapeutic effect.\u003c/p\u003e\n\u003cp\u003eA limitation of this study is the presence of selection bias associated with the choice of case reports used. We are continuing to accumulate additional cases and examining whether the simultaneous measurement of crSO₂ and mrSO₂ might be a useful method to evaluate adequate blood pressure in shock management.\u003c/p\u003e\n\u003cp\u003eIn conclusion, we evaluated the usefulness of the simultaneous measurement of crSO₂ and mrSO₂ and found that it might be an objective and noninvasive method of evaluating blood pressure management in shock patients.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003ec-mDrSO₂: difference in cerebro-musculoskeletal regional saturation of oxygen; crSO\u003csub\u003e2\u003c/sub\u003e: cerebral regional oxygen saturation; MAP: mean arterial pressure; mrSO\u003csub\u003e2\u003c/sub\u003e: muscle regional oxygen saturation; rSO₂: regional oxygen saturation; SpO₂: pulse oximetric saturation.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approvals and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study protocol was approved by the Institutional Review Board of Osaka University (Approval Number: 19540), which waived the need to obtain patient written informed consent because of the observational nature of the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe need to obtain patient written informed consent was waived because of the observational nature of the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work received research funding from ZENKYOREN (National Mutual Insurance Federation of Agricultural Cooperatives).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA.M., R.T., and M.O. conceived the study, and participated in its design. A.M., S.N., and J.T. collected and generated the data. A.M. wrote the first draft. T.H helped to draft the manuscript. All of the authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe gratefully acknowledge the devoted cooperation of the Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eCrookes BA, Cohn SM, Bloch S, Amortegui J, Manning R, Li P, Can near-infrared spectroscopy identify the severity of shock in trauma patients?. J Trauma. 2005;58(4):806-816.\u003c/li\u003e\n\u003cli\u003eJ\u0026ouml;bsis FF. Noninvasive, infrared monitoring of cerebral and myocardial oxygen sufficiency and circulatory parameters. Science. 1977;198:1264\u0026ndash;7.\u003c/li\u003e\n\u003cli\u003eVaris E, Pettil\u0026auml; V, Wilkman E. Near-infrared spectroscopy in adult circulatory shock: a systematic review. J Intensive Care Med. 2020;35:943\u0026ndash;62.\u003c/li\u003e\n\u003cli\u003eTakegawa R, Shiozaki T, Ogawa Y, Hirose T, Mori N, Ohnishi M, et al. Usefulness of cerebral rSO(2) monitoring during CPR to predict the probability of return of spontaneous circulation. Resuscitation. 2019;139:201\u0026ndash;7.\u003c/li\u003e\n\u003cli\u003eEhara N, Hirose T, Shiozaki T, Wakai A, Nishimura T, Mori N, et al. The relationship between cerebral regional oxygen saturation during extracorporeal cardiopulmonary resuscitation and the neurological outcome in a retrospective analysis of 16 cases. J Intensive Care. 2017;5:20.\u003c/li\u003e\n\u003cli\u003eMori N, Hirose T, Shiozaki T, Ogawa Y, Takegawa R, Tachino J, et al. Effectiveness of the hemoglobin index for screening of subarachnoid hemorrhage in out‐of‐hospital cardiopulmonary arrest patients: a retrospective observational study. Acute Med Surg. 2019;7:e450.\u003c/li\u003e\n\u003cli\u003eKirkman E, Watts S. Haemodynamic changes in trauma. Br J Anaesth. 2014;113:266\u0026ndash;75. doi:10.1093/bja/aeu232\u003c/li\u003e\n\u003cli\u003eRothe CF, Nash FD, Thompson DE. Patterns in autoregulation of renal blood flow in the dog. Am J Physiol. 1971;220:1621\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003eSchnell D, Camous L, Guyomarc'h S, Duranteau J, Canet E, Gery P, et al. Renal perfusion assessment by renal Doppler during fluid challenge in sepsis. Crit Care Med. 2013;41:1214\u0026ndash;20.\u003c/li\u003e\n\u003cli\u003eLerolle N, Gu\u0026eacute;rot E, Faisy C, Bornstain C, Diehl JL, Fagon JY. Renal failure in septic shock: predictive value of Doppler-based renal arterial resistive index. Intensive Care Med. 2006;32:1553\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eMesquida J, Gruartmoner G, Mart\u0026iacute;nez ML, Masip J, Sabatier C, Espinal C, et al. Thenar oxygen saturation and invasive oxygen delivery measurements in critically ill patients in early septic shock. Shock. 2011;35:456\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eMesquida J, Espinal C, Gruartmoner G, Masip J, Sabatier C, Baigorri F, et al. Prognostic implications of tissue oxygen saturation in human septic shock. Intensive Care Med. 2012;38:592\u0026ndash;7.\u003c/li\u003e\n\u003cli\u003e13. Georger J-F, Hamzaoui O, Chaari A, Maizel J, Richard C, Teboul J-L. Restoring arterial pressure with norepinephrine improves muscle tissue oxygenation assessed by near-infrared spectroscopy in severely hypotensive septic patients. Intensive Care Med. 2010;36:1882\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eOrbegozo D, Su F, Xie K, Rahmania L, Taccone FS, De Backer D, et al. Peripheral muscle near-infrared spectroscopy variables are altered early in septic shock. Shock. 2018;50:87\u0026ndash;95.\u003c/li\u003e\n\u003cli\u003eThooft A, Favory R, Salgado DR, Taccone FS, Donadello K, De Backer D, et al. Effects of changes in arterial pressure on organ perfusion during septic shock. Crit Care. 2011;15:R222.\u003c/li\u003e\n\u003cli\u003eMcKinley BA, Marvin RG, Cocanour CS, Moore FA. Tissue hemoglobin O2 saturation during resuscitation of traumatic shock monitored using near infrared spectrometry. J Trauma. 2000;48:637\u0026ndash;42.\u003c/li\u003e\n\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":"Near-infrared spectroscopy, shock, rSO2 monitor, muscle rSO2, brain rSO2","lastPublishedDoi":"10.21203/rs.3.rs-570750/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-570750/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eIn the field of emergency medical care, we often experience a situation in which we cannot measure pulse oximetric saturation (SpO₂) or blood pressure due to circulatory failure associated with shock. However, as we can measure rSO₂ values of the brain even in patients with shock, we hypothesized that we could evaluate the oxygen supply-demand balance between brain and muscle tissue by simultaneously measuring regional oxygen saturation (rSO₂) values of the brain and muscle tissue of patients with shock.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eCase presentation\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eWe attached a TOS-OR rSO₂ monitor (TOSTEC CO., Tokyo, Japan) to 10 healthy volunteers and measured the rSO₂ values of their brain and muscle for 3 minutes. The rSO₂ values of their brain cerebral regional oxygen saturation (crSO₂) and muscle regional oxygen saturation (mrSO₂) were 77.6±1.6% and 76.2±1.3% (mean ± SD). There was little difference between crSO₂ and mrSO₂ (cerebro-musculoskeletal difference in regional saturation of oxygen; c-mDrSO₂). However, there were discernible amount of c-mDrSO₂ in three cases with shock, Case 1 showed a prolonged shock state due to septic shock caused by bacterial pneumonia. Her crSO₂ values was always higher than her mrSO₂ value, and there was a c-mDrSO₂. Case 2 showed a decrease in mean arterial pressure (MAP) with the development of septic shock caused by intestinal perforation. His crSO₂ value was higher than that of his mrSO₂, and c-mDrSO₂ increased with the decrease of his MAP. Case 3 had a low MAP due to hemorrhagic shock caused by postpartum hemorrhage. Her crSO₂ value was higher than that of her mrSO₂ and a c-mDrSO₂ was present. After resuscitation, the c-mDrSO₂ decreased with the increase in her blood pressure.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\u003cp\u003eWe evaluated the usefulness of simultaneous measurement of crSO₂ and mrSO₂ as an objective and non-invasive method in shock management. Even if SpO₂ or blood pressure could not be measured due to circulatory failure associated with shock, it was possible to measure the values of crSO₂ and mrSO₂, which changed in real time with fluctuation of the blood pressure. Unlike previous monitoring devices, the rSO₂ monitor may continuously and clearly reflect the changes in local oxygen supply-demand balance.\u003c/p\u003e","manuscriptTitle":"Usefulness of Simultaneous Measurement of Brain and Muscle rSO2 (Regional Oxygen Saturation) in Shock Patients: a Report of Three Cases","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2021-06-03 14:43:25","doi":"10.21203/rs.3.rs-570750/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":"23d97952-a169-4dae-b69e-c9494f93d42d","owner":[],"postedDate":"June 3rd, 2021","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":4770307,"name":"Critical Care \u0026 Emergency Medicine"}],"tags":[],"updatedAt":"2021-06-16T06:24:18+00:00","versionOfRecord":[],"versionCreatedAt":"2021-06-03 14:43:25","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-570750","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-570750","identity":"rs-570750","version":["v1"]},"buildId":"wLkW0s4AflPzk-lpfg-fK","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}