Respiratory support techniques to avoid desaturation in critically ill patients requiring endotracheal intubation: A systematic review and meta-analysis

Purpose To evaluate which respiratory support method for critically ill patients undergoing endotracheal intubation (ETI) is associated with less desaturation. Methods We searched PubMed, Cochrane Library, Scopus and CINAHL databases. We included randomized (RCT) and non-randomized (non-RCT) studies investigating any method of respiratory support before/during ETI compared to a reference control. Results Apneic oxygenation (ApOx) was the most commonly investigated respiratory support technique for critically ill patients undergoing intubation (4 RCTs, 358 patients). Three of these studies investigated high-flow nasal cannula (HFNC) for ApOx while standard nasal cannula was used in one. Globally, ApOx was associated with higher minimum SpO2 value compared to those receiving ETI without ApOx (mean difference 2.31%, 95% CI 0.42 to 4.20, p = 0.02, I2 = 0%) but there were not significant differences between groups in severe hypoxemia and intubation related – complications. Concerning other techniques, noninvasive ventilation (NIV) was compared to bag-valve mask in only one RCT and it reduced the degree of desaturation. Conclusions ApOx was significantly associated with higher minimum SpO2 registered during the intubation procedure. Further studies are needed to increase the number of included patients and demonstrate the benefit of ApOx and of other respiratory support methods (e.g. NIV, HFNC).