Long-term cognition similar between varying oxygenation targets in mechanical ventilation
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Key takeaways:
- The Telephone Montreal Cognitive Assessment was used to evaluate global cognition in each oxygen saturation target group.
- Mechanically ventilated adults from the PILOT trial participated in this study.
Different oxygen saturation targets did not significantly impact 1-year cognition or quality of life in mechanically ventilated adults, according to results published in American Journal of Respiratory and Critical Care Medicine.
“Titrating oxygen therapy to a goal saturation is among the most common interventions performed in an ICU on a daily basis, impacting millions of patients each year,” Matthew F. Mart, MD, MSc, assistant professor in the division of allergy, pulmonary and critical care medicine at Vanderbilt University Medical Center, told Healio.
“Our data suggest that clinicians can select an oxygen target anywhere in the ranges studied or recommended by professional societies and feel comfortable knowing that such decisions are unlikely to impact most patients’ long-term quality of life,” he continued.
In the CO-PILOT study, Mart and colleagues evaluated 501 mechanically ventilated critically ill adults from the PILOT trial to see how different oxygenation saturation targets impact global cognition, disability, employment status and quality of life at 12 months.
As Healio previously reported, the PILOT study revealed that different oxygen saturation targets ranging from 90% to 98% did not significantly impact days alive without a mechanical ventilator among adults in the ICU or ED.
Within the total cohort, 142 patients (median age, 55 years; 49% women; 84% white) had a low oxygen saturation target of 88% to 92%, 186 (median age, 58 years; 50% women; 82% white) had an intermediate target of 92% to 96% and 173 (median age, 51 years; 46% women; 80% white) had a high target of 96% to 100%.
The low target group had the lowest median peripheral oxygen saturation (94%), followed by the intermediate target group (95%) and the high target group (97%).
In terms of Telephone Montreal Cognitive Assessment scores that range from 0 to 22 (higher signals better), all three groups had a median score of 17.
“One notable finding from our trial was that over 40% of survivors had evidence of cognitive impairment at 12 months, highlighting how significant ICU-acquired morbidity remains for our ICU survivors,” Mart told Healio.
Based on results from the Telephone Montreal Cognitive Assessment, researchers observed no significant difference in the likelihood for global cognition at 12 months between three target group combinations:
- low vs. intermediate target (adjusted OR = 1.36; 95% CI, 0.92-2);
- intermediate vs. high target (aOR = 0.9; 95% CI, 0.62-1.29); and
- high vs. low target (aOR = 1.22; 95% CI, 0.83-1.79).
This outcome was also found when researchers divided patients according to race (non-Black vs. Black), cardiac arrest, COPD, heart failure, coronary artery disease and end-stage renal disease.
Individual cognitive domains — executive function, attention, immediate and delayed memory, verbal fluency and abstraction — assessed in 265 patients were also similar between the oxygen saturation target groups.
Further, researchers did not find significant differences in disability (Katz Index of Independence in Activities of Daily Living and Functional Activities Questionnaire scores), employment status and health-related quality of life (EQ-5D-5 L index score) between the target groups.
“Overall, our study findings were consistent with multiple prior randomized trials of oxygen targets, whose main outcomes were short-term or in-hospital such as mortality or ventilator-free days, in that we saw no difference in outcomes between groups,” Mart told Healio. “Few prior studies have evaluated long-term outcomes in such trials, so it was exciting to publish these data to add to the scientific knowledge on the topic.”
Moving forward, Mart recommends that studies evaluate more outcomes.
“Future critical care trials will increasingly include outcomes beyond the hospital with the growing recognition of the importance of understanding patient-focused outcomes beyond mortality,” Mart told Healio. “With that growth, the science of accurately assessing such outcomes will also continue to improve.
“As for studies of oxygen targets, I anticipate an increasing focus on measuring individual treatment effects to identify those patients most likely to benefit from our interventions,” Mart added.