https://doi.org/10.4081/ecj.2026.15247
SpO₂ monitoring in emergency and acute care: clinical utility, limitations, and interpretation pitfalls
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Published: 4 September 2026
Pulse oximetry provides a non-invasive numerical estimate of arterial oxygen saturation. It is simple to apply and interpret by clinicians at all levels, and its use has expanded substantially across prehospital care, emergency departments, acute care units, and household monitoring. Although pulse oximetry is portable, non-invasive, and cost-effective, its limitations are clinically important because it measures oxygen saturation rather than ventilation, oxygen delivery, or tissue oxygen utilization. Over-reliance on SpO₂ values for decisions related to oxygen administration, escalation of care, and clinical deterioration may conceal subtle but serious abnormalities. This review discusses the limitations of pulse oximetry in emergency and acute care settings, including sepsis, regional hypoperfusion, dyshaemoglobinemias, COVID-19, pulmonary embolism, hyperoxia, skin pigmentation-related bias, and other relevant clinical contexts. The central message is that SpO₂ should be interpreted as one component of a broader assessment bundle and should not substitute for comprehensive clinical evaluation.
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1. Barker SJ, Tremper KK. Pulse oximetry: applications and limitations. Int Anesthesiol Clin 1987;25:155-75. DOI: https://doi.org/10.1097/00004311-198702530-00010
2. Severinghaus JW, Honda Y. History of blood gas analysis. VII. Pulse oximetry. J Clin Monit 1987;3:135-8. DOI: https://doi.org/10.1007/BF00858362
3. West JB. Respiratory physiology: the essentials. Lippincott Williams & Wilkins; 2012.
4. Jubran A. Pulse oximetry. Crit Care 2015;19:272. DOI: https://doi.org/10.1186/s13054-015-0984-8
5. Sharaf M, Rajaram M, Mulji A. Intracardiac shunt with hypoxemia caused by right ventricular dysfunction following pericardiocentesis. Canad J Cardiol 2008;24:S60-2. DOI: https://doi.org/10.1016/S0828-282X(08)70673-1
6. Weiskopf RB, Viele MK, Feiner J, et al. Human cardiovascular and metabolic response to acute, severe isovolemic anemia. JAMA 1998;279:217-21. DOI: https://doi.org/10.1001/jama.279.3.217
7. Monnet X, Messina A, Greco M, et al. ESICM guidelines on circulatory shock and hemodynamic monitoring 2025. Intensive Care Med 2025;51:1971-2012. DOI: https://doi.org/10.1007/s00134-025-08137-z
8. Ramponi G, Gianni F, Karlafti E, et al. The diagnostic accuracy of carbon monoxide pulse oximetry in adults with suspected acute carbon monoxide poisoning: a systematic review and meta-analysis. Front Med 2023;10:1250845. DOI: https://doi.org/10.3389/fmed.2023.1250845
9. Haymond S, Cariappa R, Eby CS, Scott MG. Laboratory assessment of oxygenation in methemoglobinemia. Clin Chem 2005;51:434-44. DOI: https://doi.org/10.1373/clinchem.2004.035154
10. Gharahbaghian L, Massoudian B, DiMassa G. Methemoglobinemia and sulfhemoglobinemia in two pediatric patients after ingestion of hydroxylamine sulfate. Western J Emerg Med 2009;10:197.
11. Barker SJ, Tremper KK. The effect of carbon monoxide inhalation on pulse oximetry and transcutaneous PO2. Anesthesiology 1987;66:677-9. DOI: https://doi.org/10.1097/00000542-198705000-00014
12. Taylor-Williams M, Spicer G, Bale G, Bohndiek SE. Noninvasive hemoglobin sensing and imaging: optical tools for disease diagnosis. J Biomed Optics 2022;27:080901. DOI: https://doi.org/10.1117/1.JBO.27.8.080901
13. Pianosi P, Charge TD, Esseltine DW, Coates AL. Pulse oximetry in sickle cell disease. Arch Dis Childhood 1993;68:735-8. DOI: https://doi.org/10.1136/adc.68.6.735
14. Chan ED, Chan MM, Chan MM. Pulse oximetry: understanding its basic principles facilitates appreciation of its limitations. Respiratory Med 2013;107:789-99. DOI: https://doi.org/10.1016/j.rmed.2013.02.004
15. Yan YS, Zhang YT. An efficient motion-resistant method for wearable pulse oximeter. IEEE Transactions in Information Technology in Biomedicine 2008;12:399-405. DOI: https://doi.org/10.1109/TITB.2007.902173
16. Desalu I, Diakparomre OI, Salami AO, Abiola AO. The effect of nail polish and acrylic nails on pulse oximetry reading using the Lifebox oximeter in Nigeria. Nigerian Postgrad Med J 2013;20:331-5. DOI: https://doi.org/10.4103/1117-1936.164638
17. Trivedi NS, Ghouri AF, Shah NK, et al. Effects of motion, ambient light, and hypoperfusion on pulse oximeter function. J Clin Anesthesia 1997;9:179-83. DOI: https://doi.org/10.1016/S0952-8180(97)00039-1
18. Bickler PE, Feiner JR, Severinghaus JW. Effects of skin pigmentation on pulse oximeter accuracy at low saturation. Anesthesiology 2005;102:715-9. DOI: https://doi.org/10.1097/00000542-200504000-00004
19. Jamali H, Castillo LT, Morgan CC, et al. Racial disparity in oxygen saturation measurements by pulse oximetry: evidence and implications. Ann Am Thoracic Soc 2022;19:1951-64. DOI: https://doi.org/10.1513/AnnalsATS.202203-270CME
20. Sjoding MW, Dickson RP, Iwashyna TJ, et al. Racial bias in pulse oximetry measurement. New Engl J Med 2020;383:2477-8. DOI: https://doi.org/10.1056/NEJMc2029240
21. Fawzy A, Wu TD, Wang K, et al. Racial and ethnic discrepancy in pulse oximetry and delayed identification of treatment eligibility among patients with COVID-19. JAMA Internal Med 2022;182:730-8. DOI: https://doi.org/10.1001/jamainternmed.2022.1906
22. Lipnick MS, Ehie O, Igaga EN, Bicker P. Pulse oximetry and skin pigmentation—new guidance from the FDA. JAMA 2025;333: 1393-5. DOI: https://doi.org/10.1001/jama.2025.1959
23. Lightdale JR, Goldmann DA, Feldman HA, et al. Microstream capnography improves patient monitoring during moderate sedation: a randomized, controlled trial. Pediatrics 2006;117:e1170-8. DOI: https://doi.org/10.1542/peds.2005-1709
24. Thomas A, van Diepen S, Beekman R, et al Oxygen supplementation and hyperoxia in critically ill cardiac patients: from pathophysiology to clinical practice. JACC: Advances 2022;1:100065. DOI: https://doi.org/10.1016/j.jacadv.2022.100065
25. O'Driscoll BR, Howard LS, Earis J, Mak V. BTS guideline for oxygen use in adults in healthcare and emergency settings. Thorax 2017;72:ii1-90. DOI: https://doi.org/10.1136/thoraxjnl-2016-209729
26. Chu DK, Kim LH, Young PJ, et al. Mortality and morbidity in acutely ill adults treated with liberal versus conservative oxygen therapy (IOTA): a systematic review and meta-analysis. Lancet 2018;391:1693-705. DOI: https://doi.org/10.1016/S0140-6736(18)30479-3
27. Wang CH, Chang WT, Huang CH, et al. The effect of hyperoxia on survival following adult cardiac arrest: a systematic review and meta-analysis of observational studies. Resuscitation 2014;85:1142-8. DOI: https://doi.org/10.1016/j.resuscitation.2014.05.021
28. Tobin MJ, Laghi F, Jubran A. Why COVID-19 silent hypoxemia is baffling to physicians. Am J Respir Crit Care Med 2020;202:356-60. DOI: https://doi.org/10.1164/rccm.202006-2157CP
29. Xie J, Covassin N, Fan Z, et al. Association between hypoxemia and mortality in patients with COVID-19. Mayo Clinic Proceedings 2020;95:1138-47. DOI: https://doi.org/10.1016/j.mayocp.2020.04.006
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