Airway management is a critical part of the management of patients presenting with traumatic brain injury (TBI). Emergency Physicians (EPs) have no ability to change the primary injury once it has occurred and so our focus is on preventing secondary brain injury. Hypoxemia and hypercarbia are major contributors to morbidity and mortality and management must focus on preventing them. Patients with TBI and depressed mental status frequently require definitive airway management in order to avoid these secondary insults. Rapid sequence intubation (RSI) with serial administration of a neuromuscular blocking agent (NMBA) and an induction agent is common practice. The most commonly used NMBAs are the depolarizing agent succinylcholine and the non-depolarizing agent rocuronium. There are strong proponents arguing for the dominance of one agent over the other based on qualities of the drugs but scant data investigating the question has led to clinical equipoise.
Which NMBA, succinylcholine or rocuronium, is preferred during RSI of patients with TBI in terms of mortality rate.
All patients > 18 years of age with a TBI who were intubated with either succinylcholine or rocuronium in the Emergency Department (ED)
Retrospective cohort study
- 260 patients with TBI were intubated in the ED
- 235 patients with TBI received a NMBI
- 233 patients with TBI received either succinylcholine (n = 149) or rocuronium (n = 84) for RSI
- Succinylcholine vs. Rocurnium mortality
- Overall: 23% vs. 23%
- Low-severity head injury (AIS < 4): 14% vs. 22% (OR 0.75 95% CI 0.29 – 1.92)
- High-severity head injury (AIS > 4): 44% vs. 23% (OR 4.10 95% CI 1.18 – 14.12)
- The largest study investigating the possible association between the choice of NMBA RSI for TBI and mortality
- Authors describe a possible pathophysiologic mechanism for their findings (increased ICP associated with succinylcholine administration)
- Retrospective study where clinicians decided NMBA agent introduces significant selection bias
- Succinylcholine group may have been sicker at baseline with more hypoxemia and hypotension (though Injury Severity Score and Head Abbreviated Injury Scale similar). The authors did do logistic regression to attempt to account for these differences
- Stratification into high and low-severity head injury (yielding the only critical finding in the study) was not the original intention of the study investigators but was performed after they identified statistical interaction
- No discussion of other confounders – sedative agents used, need for neurosurgery
- No breakdown provided of number in the low and high-risk groups (only given median AIS score)
- Although succinycholine may transiently increase ICP, the biologic plausibility of a single dose changing mortality is tenuous.
“In severely brain-injured patients undergoing RSI in the ED, succinylcholine was associated with increased mortality compared with rocuronium.”
The data provided by the authors after stratification of severity of injury appears to favor the use of rocurnium over succinylcholine during RSI in patients with TBI. However, the retrospective nature of this study only provides us with an association, not causation. The study’s retrospective nature puts it at significant risk for selection bias. A prospective, randomized controlled trial is needed to further elucidate the presence or absence of a relationship between increased mortality and choice of NMBA.
Potential Impact To Current Practice
Without high-quality data, this study cannot be used to change current practice. However, in the absence of better data, this study can be used to support the use of rocuronium over succinylcholin in RSI in high-severity TBI patients.
The best available data shows an association between the use of succinylcholine and mortality in patients with severe TBI requiring RSI. Rocuronium is at least equivalent in terms of outcomes but may be superior.
UMEM Educational Pearls: Does Succinylcholine Increase Mortality in Severe TBI Patients?