Noninvasive ventilation for preoxygenation, positive pressure ventilation during induction, and video laryngoscopy were associated with improved outcomes during emergency tracheal intubation in critically ill patients, according to a review of randomized trials.

The review synthesized randomized trials conducted over the past two decades examining oxygenation strategies, induction medications, neuromuscular blockade, and airway devices used during emergency tracheal intubation in the emergency department and intensive care unit. Outcomes included hypoxemia, first-attempt intubation success, hypotension, and cardiac arrest.

Methods and Findings

Across three randomized trials, including the PREOXI trial (Pragmatic Trial Examining Oxygenation Prior to Intubation), preoxygenation with noninvasive ventilation reduced hypoxemia compared with an oxygen mask. In PREOXI, hypoxemia occurred in 8% of patients receiving noninvasive ventilation vs 19% with an oxygen mask, and cardiac arrest occurred in 0.2% vs 1.1%.

Noninvasive ventilation reduced hypoxemia across subgroups, including patients with encephalopathy and those not receiving supplemental oxygen prior to enrollment.

In a randomized trial comparing noninvasive ventilation with high-flow nasal cannula, hypoxemia occurred in 23% vs 27% of patients, respectively; among patients with moderate to severe hypoxemia, rates were 24% vs 35%.

The PreVent trial (Preventing Hypoxemia with Manual Ventilation during Endotracheal Intubation), which enrolled 401 critically ill patients, found that bag-mask ventilation between induction and laryngoscopy reduced hypoxemia to 11% vs 23% without ventilation, with similar aspiration rates (2.5% vs 4%).

Randomized trials evaluating apneic oxygenation during laryngoscopy did not show improvements in oxygen saturation or hypoxemia.

For induction medications, randomized trials comparing ketamine with etomidate showed variable results. In the KETASED trial (n = 469), 28-day mortality was 31% with ketamine vs 35% with etomidate. In the EvK trial (n = 801), seven-day mortality was 15% vs 23%, respectively.

Evidence for neuromuscular blockade in critically ill patients remains limited. A randomized trial in the operating room reported higher first-attempt success with neuromuscular blockade (94% vs 89%), though applicability to emergency settings may be limited.

Two randomized trials, PrePARE and PREPARE II, enrolling 337 and 1,067 critically ill patients, found that a 500-mL intravenous fluid bolus prior to induction did not reduce hypotension, vasopressor use, or cardiac arrest.

Video laryngoscopy improved first-attempt success compared with direct laryngoscopy. In the DEVICE trial (n = 1,417), success occurred in 85% of patients using video laryngoscopy vs 71% with direct laryngoscopy.

In the STYLETO trial (n = 999), first-attempt success occurred in 78% of patients receiving an endotracheal tube with stylet vs 72% with a tube alone.

Two randomized trials comparing bougie vs stylet showed differing results: 98% vs 87% in the BEAM trial and 80% vs 83% in the BOUGIE trial.

Limitations

Many aspects of emergency tracheal intubation remain unsupported by randomized evidence, including optimal neuromuscular blockade strategies, vasopressor use, airway device selection in specific scenarios, and endotracheal tube size.

Some findings are based on trials conducted outside emergency department and intensive care unit settings or on observational data, which may limit generalizability.

Conclusion

“Systematically conducting randomized trials to examine every aspect of this common and high-risk procedure is improving procedural and patient outcomes and has the potential to bring forth an era of evidence-based emergency tracheal intubation,” wrote Stephanie C. DeMasi, MD, of Vanderbilt University Medical Center, and colleagues

Disclosures: The researchers reported funding support from the National Institutes of Health, the National Heart, Lung, and Blood Institute, the Patient-Centered Outcomes Research Institute, and the US Department of Defense; full disclosures are available in the article.

Source: American Journal of Respiratory and Critical Care Medicine