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. 2022 Sep;66(8):910-922.
doi: 10.1111/aas.14107. Epub 2022 Jul 7.

Long-term effects of lower versus higher oxygenation levels in adult ICU patients-A systematic review

Elena Crescioli  1   2 , Kirsten Uldal Krejberg  2 , Thomas Lass Klitgaard  1   2 , Frederik Mølgaard Nielsen  1   2 , Marija Barbateskovic  3 , Conni Skrubbeltrang  4 , Morten Hylander Møller  5 , Olav Lilleholt Schjørring  1   2 , Bodil Steen Rasmussen  1   2
Affiliations

Long-term effects of lower versus higher oxygenation levels in adult ICU patients-A systematic review

Elena Crescioli et al. Acta Anaesthesiol Scand. 2022 Sep.

Abstract

Background: Oxygen therapy is a common treatment in the intensive care unit (ICU) with both potentially desirable and undesirable long-term effects. This systematic review aimed to assess the long-term outcomes of lower versus higher oxygenation strategies in adult ICU survivors.

Methods: We included randomised clinical trials (RCTs) comparing lower versus higher oxygen supplementation or oxygenation strategies in adults admitted to the ICU. We searched major electronic databases and trial registers. We included all non-mortality long-term outcomes. Prespecified co-primary outcomes were the long-term cognitive function measures, the overall score of any valid health-related quality of life (HRQoL) evaluation, standardised 6-min walk test, and lung diffusion capacity. The protocol was published and prospectively registered in the PROSPERO database (CRD42021223630).

Results: The review included 17 RCTs comprising 6592 patients, and six trials with 825 randomised patients reported one or more outcomes of interest. We observed no difference in cognitive evaluation via Telephone Interview for Cognitive Status (one trial, 409 patients) (mean score: 30.6 ± 4.5 in the lower oxygenation group vs. 30.4 ± 4.3 in the higher oxygenation group). The trial was judged at overall high risk of bias and the certainty of evidence was very low. Any difference was neither observed in HRQoL measured via EuroQol 5 dimensions 5 level questionnaire and EQ Visual Analogue Score (one trial, 499 patients) (mean score: 70.1 ± 22 in the lower oxygenation group vs. 67.6 ± 22.4 in the higher oxygenation group). The trial was judged as having high risk of bias, the certainty of evidence was very low. No trial reported neither the standardised 6-min walk test nor lung diffusion test.

Conclusion: The evidence is very uncertain about the effect of a lower versus a higher oxygenation strategy on both the cognitive function and HRQoL. A lower versus a higher oxygenation strategy may have a little to no effect on both outcomes but the certainty of evidence is very low. No evidence was found for the effects on the standardised 6-min walking test and diffusion capacity test.

Keywords: critical care outcomes; intensive care units; oxygen inhalation therapy; systematic review.

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Conflict of interest statement

Olav Lilleholt Schjørring and Thomas Lass Klitgaard were coordinating investigators of the Handling Oxygenation Targets in the Intensive Care Unit (HOT‐ICU) trial, and Frederik Mølgaard Nielsen is the coordinating investigator of the amended trial in COVID‐19 patients (HOT‐COVID). Bodil Steen Rasmussen is sponsor and principal investigator of the HOT‐ICU and HOT‐COVID trials. Long‐term outcomes (i.e., cognitive function evaluation and lung function tests) at 1‐year follow‐up are prespecified secondary outcomes in both trials., , Other authors declare no conflict of interest.

Figures

FIGURE 1
FIGURE 1
Preferred Reporting Items for Systematic Reviews and Meta‐Analysis flowchart
FIGURE 2
FIGURE 2
Forest plots on long‐term outcomes measured by Barthel Index (A), modified Rankin Scale (B), and Glasgow Outcome Scale (GOS) or extended GOS (C), respectively. Risk of bias legend. (A) Bias arising from the randomisation process. (B) Bias due to deviations from intended interventions. (C) Bias due to missing outcome data. (D) Bias in measurement of the outcome. (E) Bias in selection of the reported result. (F) Overall bias. Size of squares for risk ratio reflects weight of trial in pooled analysis. Horizontal bars represent 95% CI. CI, confidence interval; RR, risk ratio
See this image and copyright information in PMC

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