Effects of avoidance or use of neuromuscular blocking agents on outcomes in tracheal intubation: a Cochrane systematic review

Abstract

Cohort studies have indicated that avoidance of neuromuscular blocking agents (NMBA) is a risk factor for difficult tracheal intubation. However, the impact of avoiding NMBA on tracheal intubation, possible adverse effects, and postoperative discomfort has not been evaluated in a systematic review of randomised trials. We searched several databases for trials published until January 2017. We included randomised controlled trials comparing the effect of avoiding vs using NMBA. Two independent authors assessed risk of bias and extracted data. The risk of random errors was assessed by trial sequential analysis (TSA). We included 34 trials (3565 participants). In the four trials judged to have low risk of bias, there was an increased risk of difficult tracheal intubation with no use of NMBA [random-effects model, risk ratio (RR) 13.27, 95% confidence interval (CI) 8.19-21.49, P<0.00001, TSA-adjusted CI 1.85-95.04]. The result was confirmed when including all trials, (RR 5.00, 95% CI 3.49-7.15, P<0.00001, TSA-adjusted CI 1.20-20.77). There was a significant risk of upper airway discomfort or injury by avoiding NMBA (RR=1.37, 95% CI 1.09-1.74, P=0.008, TSA-adjusted CI 1.00-1.86). None of the trials reported mortality. Avoiding NMBA was significantly associated with difficult laryngoscopy, (RR 2.54, 95% CI 1.53-4.21, P=0.0003, TSA-adjusted CI 0.27-21.75). In a clinical context, one must balance arguments for using NMBA when performing tracheal intubation.

Drug Order in Rapid Sequence Intubation

“…In emergency intubation, successful first‐attempt intubation may be a higher priority than patient experience, especially because if venous access is lost a benzodiazepine can be administered to cause amnesia to the event . In these situations, if a sedative were the only agent administered, intubation is likely to be more difficult and prone to complications, including first‐attempt failure and vomiting and aspiration . It would be difficult for any study to definitively answer this specific question.…”

“…Rapid sequence intubation (RSI) traditionally involves the sequential administration of a sedative and neuromuscular blocking agent . The sedative agent renders the patient unconscious; the neuromuscular blocking agent produces muscle relaxation, which improves laryngeal view, reduces intubation‐associated complications, and improves the likelihood of intubation success . RSI is the most common method of emergency intubation, used in approximately 85% of ED intubations and 75% of intensive care unit intubations .…”

Intubation without NMBA: first optimise opioid dose. Comment on Br J Anaesth 2018; 120: 1150–3

“…The authors declare that they have no conflicts of interest. EditordI thank Boselli 1 for his comments on my editorial, 2 written in response to Lundstrom and colleagues' metaanalysis 3 reporting the benefits of using neuromuscular blocking agents (NMBAs) to aid tracheal intubation. My major concern with Boselli's argument is that the research he reports is limited to ASA physical status 1e2 patients receiving high doses of remifentanil (4 mg kg À1 ).…”

“…3.4e5.6) administered over 1 min, with good haemodynamic tolerance. 3 Since 1998, many studies, including our own, 3 have reported the use of remifentanil doses from 2 to 4 mg kg À1 to provide good to excellent intubating conditions with good haemodynamic tolerance in healthy patients. 3,6e9 Moreover, it was reported in 1995 that doses of remifentanil ranging from 2 mg kg À1 to as high as 30 mg kg À1 administered over 1 min resulted in only moderate reduction (~20%) in heart rate and arterial pressure.…”

Tracheal intubation without the use of neuromuscular blocking drugs. Reply to Br J Anaesth 2018; 121: e9–10

“…EditordI thank Boselli 1 for his comments on my editorial, 2 written in response to Lundstrom and colleagues' metaanalysis 3 reporting the benefits of using neuromuscular blocking agents (NMBAs) to aid tracheal intubation. My major concern with Boselli's argument is that the research he reports is limited to ASA physical status 1e2 patients receiving high doses of remifentanil (4 mg kg À1 ).…”