SpO₂ Targets Linked to Neurologic Outcomes in Those With IMV Post Cardiac Arrest

Among adult patients who received invasive mechanical ventilation (IMV) after cardiac arrest, a lower-or-intermediate saturation of peripheral oxygen (SpO₂) target was associated with an increased incidence of a favorable neurologic outcome at hospital discharge, compared with use of a higher SpO₂ target, according to study findings published in Chest.

Researchers assessed whether having a lower vs higher SpO₂ target while on IMV post cardiac arrest improved neurologic outcomes via a subgroup analysis of the Pragmatic Investigation of Optimal Oxygen Targets (PILOT) trial (ClinicalTrials.gov Identifier: NCT03537937).

The PILOT trial enrolled adults receiving IMV in the medical intensive care unit or emergency department at a single academic medical center between July 1, 2018, and August 31, 2021. The current analysis used PILOT data to compare the lower-or-intermediate SpO₂ target group (88%-96%) with the higher SpO₂ target group (96%-100%). The primary outcome was a favorable neurologic outcome at hospital discharge, which was a Cerebral Performance Category of 1 (good cerebral performance) or 2 (moderate cerebral disability) at hospital discharge.

The cohort included 339 patients; 221 were assigned to the lower-or-intermediate SpO₂ targets and 118 were assigned to the higher SpO₂ target. Their median age was 60 years, 43.5% were female, 58.7% had an in-hospital cardiac arrest, and 10.2% had an initial shockable rhythm. The median time from cardiac arrest to enrollment was 105 minutes. Participants who were assigned to the lower-or-intermediate SpO₂ targets had lower oxygen saturation and partial pressure of oxygen (PaO₂) levels compared with those assigned to the higher SpO₂ target.

At hospital discharge, a favorable neurologic outcome was observed in 50 patients (22.6%) with the lower-or-intermediate SpO₂ targets and 15 participants (12.7%) with the higher SpO₂ target (absolute risk difference, 9.9 percentage points; 95% CI, 1.8-18.1; P =.03). The adjusted analysis showed similar findings (adjusted odds ratio [OR], 2.24; 95% CI, 1.11-4.53; P =.02), as did the analysis with the Cerebral Performance Category scale as an ordinal outcome ranging from 1 (good cerebral performance) to 5 (death) (OR, 1.63; 95% CI, 0.99-2.68; P =.05).

At 28 days, 146 patients (66.1%) with the lower-or-intermediate SpO₂ targets and 89 (75.4%) with the higher SpO₂ target died before hospital discharge (absolute risk difference, –9.4 percentage points; 95% CI, –19.3 to 0.6; P =.08).

Among several limitations, the pragmatic trial and secondary analysis used only data from electronic medical records. Also, the trial enrolled patients from a medical intensive care unit, and the primary outcome assessment occurred at hospital discharge, which may differ from neurologic outcome assessments at later timepoints.

“[S]urvival with a favorable neurologic outcome occurred more often with use of a lower-or-intermediate SpO₂ target (88-96%), compared to use of a higher SpO₂ target (96-100%),” the study authors concluded. “Additional randomized clinical trials are needed to confirm these findings, particularly among patients after cardiac arrest without an initial shockable rhythm,” the researchers stated.

This article originally appeared on Pulmonology Advisor