By Philip Neuwirth, BS, MICP, CCEMTP, FP-C
If you work in the prehospital setting and you are a succinylcholine user, it’s probably because it’s your best choice [within your protocols] or because of your [Medical Directors] argument; if you can’t intubate, the paralytic will wear off within 6 min and the patient will have a return of spontaneous respirations. Let’s exam why that thought process is flawed and why succinylcholine may not always be the “go-to” drug in the pre-hospital setting.
How are these drugs administered? Succinylcholine is typically given at a dose of 1.5 mg/kg IV and in infants, a higher dose of 2 mg/kg is often used. The dose of rocuronium used in rapid sequence induction varies, but many experts recommend using 1.2 mg/kg IV (or more) during emergent intubations.
The onset of succinylcholine is typically achieved after 45-60 seconds, which many cite as a major advantage over rocuronium. Rocuronium is considered to have a slower onset of action, but at much lower doses. At a dose of 1.2 mg/kg IV, there is no difference in onset between the two given the same intubating conditions.
Now, here is where the major objection is. There is no doubt rocuronium has a much longer half-life than succinylcholine. Succinylcholine may begin to wear off in 6 min, but it’s more like 10 to 12 min. The duration of effect of rocuronium depends on the dose, but at 1.2 mg/kg, it’s approximately 90 minutes.
If you are intubating a patient in the emergent setting, it’s probably because your patient is hypoxic or hypercarbic in respiratory failure. If the drug wears off, you are back where you started; a patient in respiratory failure who needs an airway. If you used Rocuronium, to begin with, and can’t intubate, you continue with your backup airway plan B, and C, rather than having to stop, risk your patient may vomit, aspirate and have the situation spiral out of control. Keeping the patient paralyzed is an advantage in the emergent setting. If you are intubating a patient with the thought process, I can always wake the patient up; you probably should not be intubating that patient in the first place.
Succinylcholine is a great drug in elective surgeries; the doctors receive pre-operative blood work, and anesthesia can just cancel the case if the patient can’t be intubated. The patient gets ventilated for 10-12 minutes, and they’re no worse off.
For those who will continue to argue the duration of effect is too long, in December 2015, the FDA approved sugammadex for the reversal of rocuronium and vecuronium.
One of the reasons for writing this blog reminds everyone that succinylcholine has several major side-effects and contraindications as compared to rocuronium.
Rocuronium has no known side-effects (maybe a sensitivity to the drug)
Succinylcholine can cause:
- Bradycardia, potentially leading to cardiac arrest (especially in small children and following repeat doses)
- Hyperkalemia, which is potentially fatal (though K only rises about 0.4 mmol/L on average in normal individuals)
- Fasciculations which increase oxygen consumption and lead to muscle pain
- Increases in intra-gastric pressure, possibly offset by an increase in lower esophageal sphincter tone
- Increased intraocular pressure
- Malignant hyperthermia — rare, but very very bad
Rocuronium has no known contraindications
Succinylcholine should be avoided if the following conditions are present:
- Risk of Hyperkalemia
- Renal Failure (a relative CI)
- Severe Sepsis
- Congenital Myopathies
- Neuromuscular Disorders
- Upper motor neuron disorders: stroke >72h, motor neuron disease, multiple sclerosis, spinal cord injury >72h
- Burns >72h
- Crush injury
- Malignant hyperthermia
When should you still consider succinylcholine? For Flight Teams and Ground Paramedics with short transport times < 15-20 min, when a rapid and timely neurological evaluation might change patient management. For example, patients intubated for seizure control, patients with traumatic intracerebral bleeds, stroke patients, and patients who have been intubated post cardiac arrest that require a neuro assessment to determine eligibility for Targeted Temperature Management.
In the following video, Dr Strayer compares the two drugs.
Please post your comments and click “Like” if you found this informative,
- Life in the Fast Lane: Does Roc rock? Does Sux Suck? Dr Chris Nelson
- Updates in Resuscitation Podcast, Episode 52: Dr Amal Mattu, MD
- El-Orbany M, Connolly LA. Rapid sequence induction and intubation: current controversy. Anesth Analg. 2010 May 1;110(5):1318-25. Epub 2010 Mar 17. Review. PMID: 20237045.
- JM, Walls RM. Rocuronium vs. succinylcholine in the emergency department: a critical appraisal. J Emerg Med. 2009 Aug;37(2):183-8. Epub 2008 Dec 20. Review. PMID: 19097730.
- Strayer, R. EM Updates. Screencast: Rocuronium vs. Succinylcholine in 8 minutes