Sedation for awake tracheal intubation: a systematic review and network meta-analysis

Background. Different sedation regimens have been used to facilitate awake tracheal intubation, but the research has not been robustly synthesised, particularly with respect to clinically important outcomes. We therefore conducted a systematic review and network meta-analysis to determine the sedation techniques most likely to be associated with successful tracheal intubation, a shorter time to successful intubation, and a lower risk of arterial oxygen desaturation.
Methods. We sought randomised controlled trials of patients undergoing awake tracheal intubation for any indication and reporting: overall tracheal intubation success rate; tracheal intubation time; incidence of arterial oxygen desaturation; and other related outcomes. We performed a frequentist network meta-analysis for these outcomes if two or more sedation regimens were compared between included trials. We also performed a sensitivity analysis excluding trials with a high risk of bias.
Results. In total, 48 studies with 2837 patients comparing 33 different regimens were included. Comparing overall awake tracheal intubation success rates (38 studies, 2139 patients), there was no evidence suggesting that any individual sedation regimen was superior. Comparing times to successful tracheal intubation (1745 patients, 24 studies), any sedation strategy was superior to placebo. Dexmedetomidine, either alone or in combination with ketamine, was superior to most other regimens. When propofol was combined with ketamine, it was also superior to several other strategies. When we excluded trials with a high risk of bias, we found no evidence of a difference between any intervention for time to successful tracheal intubation. Low-quality evidence from 31 studies, including 1753 patients, suggested that dexmedetomidine and magnesium sulphate were associated with a reduced risk of arterial oxygen desaturation compared with other interventions, but excluding trials with a high risk of bias suggested no relevant differences between interventions. The quality of evidence for each of our outcomes was low, due to study limitations and imprecision of the evidence.
Conclusions. To maximise effective and safe awake tracheal intubation, optimising oxygenation, topical airway anaesthesia and procedural performance may have more impact than any given sedation regimen. We therefore conclude that clinicians consider the cautious administration of drugs they are experienced with.