Reviewed and revised 6th May 2016
- “Shock is an anaesthetic” so the basic rapid sequence intubation (RSI) is “roc/sux-tube-apology” in a shocked patient
- A modified RSI approach is often preferred in shocked patients, e.g. use of low does titrated induction agents to avoid haemodynamic compromise and avoidance of apnoea (e.g. via spontaneous breathing or supported ventilation) to avoid exacerbation of coexistant acidaemia. Richard Levitan has termed this approach “resuscitation sequence intubation”
- “Resuscitate before you intubate!”
- Use judicious doses of sedatives to make the procedure as non-distressing as possible, without compromising safety
- Remember that primary objective is to keep the patient alive while achieving intubation
- Peri-intubation hypotension is associated with increased mortality
- The most important risk factors for death and complications prior to intubation (Schwartz et al 1995) are:
— haemodynamic instability
— requirement for pressor agents
- underlying disease
- inadequate resuscitation
- cardiodepressant effects of induction agents
- decreased venous return due to positive pressure ventilation
- haemodynamic effects of worsening acidosis during apnoea
- adequately fluid resuscitate prior to, and during, RSI
- consider using a pressor agent (e.g. adrenaline) prior to intubation to prop up blood pressure before the administration of an induction agent
- choose an induction agent and a dose that is least likely to exacerbate hypotension (e.g. ketamine)
- avoid high tidal volumes and dynamic hyperinflation when ventilating, which exacerbates hypotension by decreasing venous return and cardiac output
CHOICE AND DOSES OF AGENTS
- the dose of any induction agent used is more important than the choice of the agent — use lower doses than usual, regardless of the agent used
- ketamine is the induction agent of choice in the shock patient (see below)
- many intensivists use fentanyl and midazolam in low doses as their mainstays for the induction of shocked patients; however onset is very slow in shocked patient (e.g. up to or greater than 5 minutes)
- even propofol and thiopentone can be used in the shocked patient, but as little as 10% of the usual dose may be all that is needed — higher doses may lead to haemodynamic compromise (aka ‘propofol assassination’)
- etomidate is not available in Australia, and may be best avoided due to ongoing concerns:
— it causes adrenal suppression which may be linked to increased mortality in septic patients (though many argue that etomidate is safe)
— it is unreliable as an induction agent in reduced doses (even in shocked patients)
- dose higher, as onset for any given dose will be slower
- e.g. suxamethonium 2mg/kg or rocuronium 1.6 mg/kg IV
- The compounding effect of uncorrected respiratory acidosis from apnea (regardless of the agents used) may be lethal
- During apnea from RSI, supported ventilation may be necessary in patients with profound metabolic acidosis
- Ketamine is the least cardio-depressant induction agent available
- Ketamine usually exhibits a stimulatory effect on the cardiovascular system: the mechanism is poorly understood but probably involves a centrally mediated sympathetic response and inhibition of noradrenaline reuptake
- In the severely shocked patient beware of catecholamine depletion or resistance to further catecholamine effect. The direct effects of ketamine on myocardial depression may outweigh the indirect sympathetic effects and haemodynamic collapse may still occur. This is more likely to occur at high doses and in patients with a higher shock index (Miller et al, 2016).
- Consider doses as low as 0.25 to 0.5mg/kg IV, rather than the usual 1-2 mg/kg IV, for RSI of the shock patient
- Rapid administration of ketamine alone can render the patient apneic: in the RSI setting, apnea will occur anyway from the administration of paralytics (see the comments above), but has important implications when ketamine is used in other settings such as procedural sedation or delayed sequence intubation (DSI)
Slides for the talk “No Apologies: Intubation of the Shocked Patient”, given at EuSEM Congress 2015 in Torino, Italy:
References and Links
- Heffner AC, Swords D, Kline JA, Jones AE. The frequency and significance of postintubation hypotension during emergency airway management. J Crit Care. 2012 Aug;27(4):417.e9-13. doi: 10.1016/j.jcrc.2011.08.011. Epub 2011 Oct 26. PubMed PMID: 22033053.
- Heier T, Caldwell JE. Rapid tracheal intubation with large-dose rocuronium: a probability-based approach. Anesth Analg. 2000 Jan;90(1):175-9. PubMed PMID: 10625000.
- Jabre P, et al; KETASED Collaborative Study Group. Etomidate versus ketamine for rapid sequence intubation in acutely ill patients: a multicentre randomised controlled trial. Lancet. 2009 Jul 25;374(9686):293-300. doi: 10.1016/S0140-6736(09)60949-1. Epub 2009 Jul 1. PubMed PMID: 19573904.
- Leeuwenburg T. Airway Management of the Critically Ill Patient: Modifications of Traditional Rapid Sequence Induction and Intubation. Critical Care Horizons [Internet]. 2015 [cited 16 September 2015];1:1-10. Available from: http://www.criticalcarehorizons.com/airway-management-of-the-critically-ill-patient/
- Lippmann M, Appel PL, Mok MS, Shoemaker WC. Sequential cardiorespiratory patterns of anesthetic induction with ketamine in critically ill patients. Crit Care Med. 1983 Sep;11(9):730-4. PubMed PMID: 6884053.
- Miller M, Kruit N, Heldreich C. Hemodynamic Response After Rapid Sequence Induction With Ketamine in Out-of-Hospital Patients at Risk of Shock as Defined by the Shock Index. Annals of emergency medicine. 2016. [pubmed]
- Morris C, Perris A, Klein J, Mahoney P. Anaesthesia in haemodynamically compromised emergency patients: does ketamine represent the best choice of induction agent? Anaesthesia. 2009 May;64(5):532-9. doi: 10.1111/j.1365-2044.2008.05835.x. Review. PubMed PMID: 19413824. [Free Fulltext]
- Scherzer D, Leder M, Tobias JD. Pro-con debate: etomidate or ketamine for rapid sequence intubation in pediatric patients. J Pediatr Pharmacol Ther. 2012 Apr;17(2):142-9. doi: 10.5863/1551-6776-17.2.142. PubMed PMID: 23118665; PubMed Central PMCID: PMC3470433.
- Schwartz DE, Matthay MA, Cohen NH. Death and other complications of emergency airway management in critically ill adults. A prospective investigation of 297 tracheal intubations. Anesthesiology. 1995 Feb;82(2):367-76. PubMed PMID: 7856895. [Free Full Text]
- Dewhirst E, Frazier WJ, Leder M, Fraser DD, Tobias JD. Cardiac Arrest Following Ketamine Administration for Rapid Sequence Intubation. J Intensive Care Med. 2012 May 29. [Epub ahead of print] PubMed PMID: 22644454.
FOAM and web resources
- Levitan R. Timing Resuscitation Sequence Intubation for Critically Ill Patients – ACEP Now [Internet]. ACEP Now. 2015 [cited 16 September 2015]. Available from: http://www.acepnow.com/article/timing-resuscitation-sequence-intubation-for-critically-ill-patients/
- EMCrit Podcast 104 – Laryngoscope as a Murder Weapon Series: Hemodynamic Kills (2013)
- EMCrit Podcast 30 – Hemorrhagic Shock Resuscitation (2012)
- MDAware — Ketamine is a Heckuva Drug (2012)
- PHARM — Assassin’s Creed and Peri-intubation Hypotension (2013)
- ResusME — Ketamine & cardiovascular stability (2013)