Written by Clay Smith
Spoon Feed
In COPD patients, a SpO2 target of 88-92% was associated with lower inpatient mortality than SpO2 targets ≥93%.
Why does this matter?
British COPD guidelines call for target SpO2 of 88-92% in patients with chronic CO2 retention; 94-98% is the target with no CO2 retention. In COPD, oxygen-induced hypercapnea is a real phenomenon that may lead to worsening acidemia and in-hospital death. Previously we have summarized numerous articles about the sweet spot for SpO2 in mechanically ventilated patients and others. LOCO2 found a low PaO2 target was associated with harm in critically ill ARDS patients. What is the ideal SpO2 for this unique population with chronic lung disease?
Run ‘em low
This was a secondary look at largely prospectively collected data for the DECAF score. There were 2,645 patients admitted with exacerbation of COPD in the DECAF derivation and validation studies, of which 1,027 needed supplemental O2. Inpatient mortality was lowest in the 88-92% group. Adjusted odds of death when comparing the 88-92% cohort was 1.98 (95%CI 1.09 to 3.60) in the 93-96% cohort; 2.97 (95%CI 1.58 to 5.58) in the 97-100% group. This was similar and statistically significant in the normocapnic subgroup as well. The data for this study was not originally collected for this purpose. So this association could be confounded. However, this figure shows a compelling dose-response that leads me to think this association is real.
Source
Oxygen therapy and inpatient mortality in COPD exacerbation. Emerg Med J. 2021 Mar;38(3):170-177. doi: 10.1136/emermed-2019-209257. Epub 2020 Nov 26.
