Comparison of Pocket Pulse Oximeter and Standard Pulse Oximeter With ABG Analysis in Critically Ill Patients

Abstract

Background: Pulse oximetry (SpO2) is a standard monitoring device in patients presenting to EMDs and intensive care units (ICUs). Pocket pulse oximeters (PPOs) are used widely in wards, EMDs, and small hospitals/clinics. These inexpensive PPOs also guide therapeutic interventions. Few studies have evaluated the accuracy of SpO2 in patients presenting to critical care areas vis-à-vis devices like PPO and standard pulse oximeter (SPO). This study becomes extremely relevant in view of the ongoing crisis of the COVID-19 pandemic wherein SpO2 monitoring is very important in hospitals, quarantine centers, small clinics, or even at home.


 Methods: Patients presenting to critical areas who underwent arterial blood gases (ABG) analysis on the recommendation of the treating physician between November 2016 and October 2018 were included in this study. Along with the ABG analysis, a simultaneous assessment of SpO2 was done with a single PPO and SPO and all values were noted. Statistical analysis was done using the SPSS v.21.0 for Windows.


 Results: The study included 300 patients. We compared the O2 saturations of ABG, SPO, and PPO with respect to sex, different age groups, and at different levels of ABG pCO2, HCO3, and pH in all patients. All parameters were compared using the Pearson’s correlation test; the results showed that ABG O2 saturations were closer to the SPO than the PPO but the differences were not statistically significant as the Pearson’s correlation values for all parameters were >0.8. We also compared the parameters by Bland Altman Plot and all observations were outside 95% CI (confidence interval), which means that there was a good agreement between O2 saturations by all three methods, that is, ABG, SPO, and PPO; however, ABG O2 saturations were closer to SPO than PPO but this difference was not statistically significant. Hence, we conclude that the PPO is a useful tool for reliable monitoring of O2 saturations.


 Conclusion: This study highlights that inexpensive and noninvasive PPO can be used as a standard monitoring device with reliability in critically ill patients presenting to EMDs, ICUs, and small hospitals/clinics, quarantine centers, and even at home.

Keywords:

pulse oximeter, standard pulse oximeter, pocket pulse oximeter, arterial blood gas analysis, oxygen saturation

References
[1] Torp, K. D., Modi, P., and Simon, L. V. (2021). Pulse oximetry. Treasure Island, FL: StatPearls Publishing.

[2] Hafen, B. B. and Sharma, S. (2021). Oxygen saturation. Treasure Island, FL: StatPearls Publishing.

[3] Singh, A., Kataria, S., Das, P., et al. (2020). A proposal to make the pulse oximetry as omnipresent as thermometry in public health care systems. Journal of Global Health, vol. 10, no. 2, p. 0203102.

[4] Michard, F., Shelley, K., and L'Her, E. (2021). COVID-19: pulse oximeters in the spotlight. Journal of Clinical Monitoring and Computing, vol. 35, no. 1, pp. 11–14.

[5] Quaresima, V. and Ferrari, M. (2020). More on pulse oximetry for monitoring patients with COVID-19 at home. Annals of the American Thoracic Society, vol. 17, no. 11, p. 1496.

[6] Van de Louw, A., Cracco, C., Cerf, C., et al. (2001). Accuracy of pulse oximetry in the intensive care unit. Intensive Care Medicine, vol. 27, no. 10, pp. 1606–1613.

[7] da Costa, J. C., Faustino, P., Lima, R., et al. (2016). Comparison of the accuracy of a pocket versus standard pulse oximeter. Biomedical Instrumentation & Technology, vol. 50, no. 3, pp. 190–193.

[8] Wilson, B. J., Cowan, H. J., Lord, J. A., et al. (2010). The accuracy of pulse oximetry in emergency department patients with severe sepsis and septic shock: a retrospective cohort study. BMC Emergency Medicine, vol. 10, no. 9.

[9] Seguin, P., Le Rouzo, A., Tanguy, M., et al. (2000). Evidence for the need of bedside accuracy of pulse oximetry in an intensive care unit. Critical Care Medicine, vol. 28, no. 3, pp. 703–706.

[10] Muñoz, X., Torres, F., Sampol, G., et al. (2008). Accuracy and reliability of pulse oximetry at different arterial carbon dioxide pressure levels. European Respiratory Journal, vol. 32, no. 4, pp. 1053–1059.

[11] Wilkerson, R. G., Adler, J. D., Shah, N. G., et al. (2020). Silent hypoxia: a harbinger of clinical deterioration in patients with COVID-19. American Journal of Emergency Medicine, vol. 38, no. 10, pp. 2243.e5–2243.e6.

[12] Brouqui, P., Amrane, S., Million, M., et al. (2021). Asymptomatic hypoxia in COVID-19 is associated with poor outcome. International Journal of Infectious Diseases, vol. 102, pp. 233–238.

[13] Philip, K. E. J., Bennett, B., Fuller, S., et al. (2020). Working accuracy of pulse oximetry in COVID-19 patients stepping down from intensive care: a clinical evaluation. BMJ Open Respiratory Research, vol. 7, no. 1, p. e000778.

[14] Moyle, J. (2021). Pulse oximetry gives artificially high readings in presence of carboxyhaemoglobin. BMJ, vol. 373, p. n1103.

[15] Yamakage, M. (2021). Pulse oximetry: the outstanding achievements of Dr. Takuo Aoyagi. Journal of Anesthesia, vol. 35, article 605.