Association between prehospital oxygen saturation and outcomes in hypotensive traumatic brain injury patients in Asia (Pan-Asian Trauma Outcomes Study (PATOS)).

BACKGROUND

It has been shown that blood pressure (BP) and peripheral oxygen saturation (SpO2) influence the outcomes in Traumatic Brain Injury (TBI) patients. This study aims to determine the association between prehospital SpO2 and in-hospital mortality in hypotensive TBI patients.

METHODS

Prehospital trauma patients who were 18 years old or above with a diagnosis of TBI using ICD 10 codes (S06.0-S06.9) and had prehospital hypotension (systolic blood pressure (SBP) < 100 mmHg for patients aged 50-69 and < 110 mmHg for patients aged 15-49 or over 70 years) recorded from November 2015 to December 2022 in participating PATOS facilities were analyzed. SpO2 was measured by Emergency Medical Services (EMS) and divided into three levels: normoxia (≥ 94%), moderate hypoxia (80-93%), and severe hypoxia (< 80%). The outcomes were survival and disability at hospital discharge. Multivariable logistic regression analysis with interaction analysis was performed to calculate the adjusted odds ratios (AORs) with 95% confidence intervals (CIs).

RESULTS

Out of 1,210 patients, 777 (64.2%) had normoxia, 319 (26.4%) had moderate hypoxia and 114 (9.4%) had severe hypoxia. Of these, survival to discharge was 92.5%, 74.9%, and 52.6% in the normoxia, moderate hypoxia, and severe hypoxia group, respectively (p < 0.0001). Favorable neurological outcomes in normoxia, moderate hypoxia, and severe hypoxia were 74.1%, 48.9 and 36%, respectively. AORs (95% CI) for survival and favorable neurological outcome compared with severe hypoxia were 3.34 (1.77-6.32)/1.83 (1.04-3.25) in the normoxia group and 2.15 (1.23-3.74)/2.23 (1.31-3.78) in the moderate hypoxia group respectively.

CONCLUSION

An initial prehospital saturation of ≥ 94% was significantly associated with better hospital outcomes in hypotensive TBI patients.