Preoxygenation strategies for intubation of patients who are critically ill: a systematic review and network meta-analysis of randomised trials

Abstract

Background

Preoxygenation is a crucial preparatory step for intubation. Several strategies for preoxygenation exist, including facemask oxygen, high-flow nasal cannula (HFNC), and non-invasive positive pressure ventilation (NIPPV). However, the comparative efficacy of these strategies remains largely uncertain. We aimed to compare the efficacy and safety of HFNC, NIPPV, and facemask oxygen for preoxygenation of patients who are critically ill requiring tracheal intubation.

Methods

In this systematic review and network meta-analysis, we searched Embase, MEDLINE, Web of Science, Scopus, and Cochrane Central Register of Controlled Trials for randomised clinical trials published from database inception until Oct 31, 2024, with no language restrictions. We included randomised controlled trials that compared HFNC versus NIPPV, HFNC versus facemask oxygen, or NIPPV versus facemask oxygen in adult patients (age ≥18 years) who were critically ill requiring intubation in the intensive care or emergency department setting. We had no additional eligibility criteria for our network meta-analysis. We used Covidence software to screen eligible trials. Two reviewers independently screened trials for titles and abstracts, and then subsequently screened full-text reports. Discrepancies were resolved by discussion or a third party adjudicator. Summary-level data were extracted manually using a structured data collection form. Outcomes of interest were hypoxaemia during intubation, successful intubation on the first attempt, serious adverse events, and all-cause mortality. We performed a frequentist random-effects network meta-analysis. We assessed the risk of bias using the modified Cochrane tool (RoB 2.0) and the certainty of evidence using the GRADE approach. The protocol is registered on the Open Science Framework.

Findings

We initially identified 6900 records, of which 48 were assessed via full-text screening, and 15 eligible studies with 3420 patients were included in our systematic review and network meta-analysis. Findings suggested that use of NIPPV for preoxygenation probably reduces the incidence of hypoxaemia during intubation versus HFNC (relative risk 0·73 [95% CI 0·55–0·98]; p=0·032; moderate certainty) and reduces the incidence of hypoxaemia versus facemask oxygen (0·51 [0·39–0·65]; p<0·0001; high certainty). HFNC for preoxygenation reduces the incidence of hypoxaemia during intubation versus facemask oxygen (0·69 [0·54–0·88]; p=0·0064; high certainty). None of the preoxygenation strategies affected the incidence of successful intubation on the first attempt (all low certainty). None of the preoxygenation strategies appeared to affect all-cause mortality (very low-to-moderate certainty). NIPPV probably reduces the risk of serious adverse events versus facemask oxygen (0·30 [0·12–0·77]; p=0·011; moderate certainty) and might reduce the risk of serious adverse events versus HFNC (0·32 [0·11–0·91]; p=0·035; low certainty). HFNC might not reduce the risk of serious adverse events versus facemask oxygen (0·95 [0·60–1·51]; p=0·83; low certainty).

Interpretation

Preoxygenation with NIPPV or HFNC rather than facemask oxygen might prevent hypoxaemia during tracheal intubation of adults who are critically ill. Compared with HFNC, NIPPV probably decreases the incidence of hypoxaemia during intubation. Our findings will inform updated international guidelines on preoxygenation.

Funding

None.