Fentanyl (Sublimaze) is a fast acting opiod recommended as pretreatment before rapid sequence intubation (RSI) when it is advisable to mitigate the sympathetic activation that occurs with laryngoscopy and endotracheal intubation. See article “Pretreatment in Rapid Sequence Intubation” on this site.
In this post I wanted to focus solely on fentanyl in RSI and for this there is no better source than the Manual of Emergency Airway Management, 4th edition, 2012. Every physician, nurse, and EMS provider should own and study this book and practice it’s techniques if there is any possibility that he or she will ever have primary responsbility for a patient who requires emergency airway management.
The following is from that book: (1)
Fentanyl attenuates the sympathetic response to laryngoscopy with minimal side effects other than dose-related respiratory depression, which is rarely an issue in the doses used for RSI pretreatment. Fentanyl does not release histamine and has no direct effect on the pulmonary response to laryngoscopy. Fentanyl has been shown to have a partial attenuating effect on the RSRL at doses as low as 2 mcg per kg IV.
For emergency intubation, we recommend fentanyl in a dose of 3 mcg per kg IV 3 minutes before the induction and paralytic agents for patients who might be adversely affected by a systemic release of catecholamines. Patients with increased ICP frequently lose the ability to autoregulate, and consequently, increases in blood pressure may exacerbate the ICP elevation. Patients with intracranial hemorrhage, ischemic heart disease, known or suspected cerebral or aortic aneurysm, or dissection or rupture of a great vessel are similarly at risk from an acute hypertensive response.
Fentanyl should be given as the last of the pretreatment drugs, over a period of 30 to 60 seconds, to minimize the likelihood of significant respiratory depression. Whenever fentanyl is given, watch the patient for signs of hypoventilation before administration of the sedative and paralytic agents. Because fentanyl is given to reduce sympathetic tone, extreme caution must be used in the hemodynamically compromised patient who is dependent on sympathetic tone to maintain hemodynamic stability (e.g., compensated or decompensated shock). Fentanyl is not recommended in pediatric RSI because the administration would further complicate the resuscitation, and the benefit for children has not been demonstrated.
Muscle wall rigidity is a unique and idiosyncratic response to opioids and is probably related to the dose and speed of opioid administration, the concomitant use of nitrous oxide, and the absence of muscle relaxants. It is not reversible with naloxone (Narcan). It is usually seen with fentanyl doses well in excess of 500 mcg (0.5 mg) and primarily affects the chest and abdominal wall musculature. The rigidity tends to occur very quickly after the patient begins to lose consciousness, and it is abolished by the administration of paralyzing doses of succinylcholine, once the abnormality is recognized. Rigidity has not been reported with the use of fentanyl in the emergency department. Because fentanyl is used in relatively low doses for emergency RSI, it is exceedingly unlikely that any muscle rigidity will occur.
Recommendations for the use of fentanyl as a pretreatment agent for emergency RSI are
given in Box 20-3 [in the text]. Three important caveats apply to the use of fentanyl as a pretreatment agent during RSI:
1. Avoid fentanyl pretreatment if the patient is in compensated or decompensated shock, or minimally hemodynamically stable and dependent on sympathetic drive
2. Be prepared for dose-related respiratory depression.
3. Give fentanyl as the final pretreatment agent and administer over 30 to 60 seconds.”
The authors advice against using fentanyl pretreatment in children: (2)
“There is excellent evidence that premedication with synthetic opioids [like fentanyl] before direct laryngoscopy and tracheal intubation attenuates the increase in ICP, intraocular pressure, mean arterial pressure, myocardial oxygen consumption and pulmonary arter pressure caused by this noxious stimulus. The attenuation of the reflex sympathetic response to laryngoscopy and intubation conferred by pretreatment with an opiod is dose dependent and generally requires 3 to 5 minutes for peak effect (fentanyl). During this time, the side effects of a narcotic can be significant (respiratory depression, cough, hypotension, and stiff chest. RSI in an emergency is usually a life-threatening cardiorespiratory event that already has created a stress-induced increase in catechols. For this reason, and because the dosing and administration of small doses of opioids in children is fraught with the potential for overdose, we do not routinely recommend use of opiods in children and place more emphasis on induction of general anesthesia and rapid onset of muscle relaxation to create ideal intubating conditions.”
(1) The Manual of Emergency Airway Management, 4th edition, 2012. RM Walls and MF Murphy, pp 236 + 237.
(2) Ibid., p 290.
