Rapid sequence induction in the emergency department: Rocuronium vs Succinylcholine

Awareness With Paralysis is a frightening situation that leaves its mark. The risk of occurrence after intubation is probably underestimated in the emergency room.

About the author: Prof. Nicolas Peschanski works as an Emergency Medicine consultant at the Centre Hospitalier Universitaire de Rennes, France. Translated from the original French version. His articles, which he originally writes for our partners at esanum.fr, are a compilation of case studies and topics on medical specialties that Prof. Peschanski presents to his students for group discussion.

A common, but risky procedure

Rapid sequence induction (RSI) orotracheal intubation is a common procedure in the emergency department. In this technique, a paralyzing agent such as succinylcholine or rocuronium is used. Sedation is provided by a short-acting anaesthetic such as ketamine or etomidate, or even propofol.

Continuous sedation and analgesia must then be provided as long as the patient is mechanically ventilated, otherwise there is a significant risk of vigorous paralysis if a medium or long acting agent is used.

Awareness With Paralysis (AWP) is rather difficult for the patient to cope with. They are aware of their surroundings but cannot act or even communicate their disorder. This can lead not only to a painful experience but also to considerable psychological trauma in the long term. However, in the sometimes busy and chaotic environment of emergency departments, a scenario where sedation is delayed or insufficient is possible. This scenario is even more plausible if a long-acting paralytic drug, such as rocuronium, is used.

An underestimated risk in the emergency room?

Two recent studies shed light on this potentially underestimated risk. The ED-AWARENESS study is a prospective, single-centre, observational cohort study of 383 mechanically ventilated emergency patients. It was published in 2021 in Annals of Emergency Medicine.1

After extubation, the authors assessed patients' AWP using the modified Brice questionnaire. Ten of the patients had paralysis with awareness, a prevalence of 2.6%. The odds ratio for AWP with rocuronium was 5.1 compared to succinylcholine (i.e. a 5-fold risk!).

More recently (2022), the same team published in Critical Care Medicine a multicentre prospective cohort study to add to the knowledge on this subject.2 Just under 400 patients participated in the study. Of the 3.4% who experienced an episode of AWP, all but one had received rocuronium as a neuromuscular paralytic curare for RSI.

Furthermore, these "rocuronium patients" also had a significantly higher mean Brice score (this score assesses the perception of awareness). This suggests a higher risk of post-traumatic stress disorder after the procedure.

What can we learn from these results?

The first single-centre study suggests that a significant number of patients may face AWP in emergency departments. This risk appears to be increased by the use of rocuronium. The caution associated with the RSI procedure should therefore also apply to the maintenance of analgesia-sedation in order to prevent the occurrence of AWP.

The second multicentre study consolidates the results of the first. The authors concluded that: "AWP was present in a concerning proportion of mechanically ventilated ED patients, was associated with rocuronium exposure in the ED, and led to increased levels of perceived threat, placing patients at greater risk for PTSD. Studies that aim to further quantify AWP in this vulnerable population and eliminate its occurrence are urgently needed."

In this latest study, the observed rate of 3.4% of AWP  in the ER is much higher than the reported incidence in operating room patients (0.1%). This suggests that there is room for improvement in analgesia-sedation maintenance practices following RSI application in emergency patients.

Implications for medical practice

Rocuronium is an interesting pharmacological agent for induction during a rapid sequence intubation procedure. But beware of its effect duration, which is longer than that of succinylcholine. The emergency physician should take enhanced measures to maintain analgesic-sedation after RSI to prevent AWP occurrence. 

The adage "Roc Rocks & Succ Sucks!" of American emergency physicians should probably be weighed up quite somewhat.

  1. Pappal RD, Roberts BW, Mohr NM, Ablordeppey E, Wessman BT, Drewry AM, Winkler W, Yan Y, Kollef MH, Avidan MS, Fuller BM. The ED-AWARENESS Study: A Prospective, Observational Cohort Study of Awareness With Paralysis in Mechanically Ventilated Patients Admitted From the Emergency Department. Ann Emerg Med. 2021 May;77(5):532-544. doi: 10.1016/j.annemergmed.2020.10.012. Epub 2021 Jan 21. PMID: 33485698; PMCID: PMC8166299.
  2. Fuller BM, Pappal RD, Mohr NM, Roberts BW, Faine B, Yeary J, Sewatsky T, Johnson NJ, Driver BE, Ablordeppey E, Drewry AM, Wessman BT, Yan Y, Kollef MH, Carpenter CR, Avidan MS. Awareness With Paralysis Among Critically Ill Emergency Department Patients: A Prospective Cohort Study. Crit Care Med. 2022 Oct 1;50(10):1449-1460. doi: 10.1097/CCM.0000000000005626. Epub 2022 Jul 21. PMID: 35866657.