What recent findings are leading clinicians to reconsider ketamine as a frontline rapid‑sequence intubation induction agent in the prehospital setting and favor etomidate instead?

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Last updated: October 18, 2026 • View editorial policy

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Emerging Concerns About Ketamine in Prehospital RSI

Recent evidence demonstrates that ketamine is associated with significantly higher rates of post-intubation hypotension compared to etomidate in the prehospital setting, challenging its position as a frontline RSI induction agent. While ketamine was previously favored for its presumed hemodynamic stability through sympathomimetic effects, multiple large-scale studies now reveal this advantage may not hold in critically ill patients with depleted catecholamine stores.

Key Findings Driving the Reconsideration

Increased Hypotension Risk with Ketamine

The most compelling evidence comes from recent large-scale analyses showing ketamine consistently produces more hemodynamic instability than etomidate:

  • A 2026 retrospective analysis of 10,727 prehospital patients found etomidate was associated with 44% lower odds of cardiovascular collapse (defined as SBP <65 mmHg, vasopressor need, or cardiac arrest) compared to ketamine (aOR 0.56,95% CI 0.48-0.65) 1

  • Two separate evaluations of National Emergency Airway Registry data demonstrated higher hypotension rates with ketamine: 18.3% versus 12.4% for etomidate in one study, and a propensity-adjusted OR of 2.7 (95% CI 1.1-6.7) for post-RSI hypotension with ketamine in septic patients 22

  • A 2026 meta-analysis of six RCTs (4,108 patients) confirmed ketamine increases post-intubation hypotension risk by 25% (RR 1.25,95% CI 1.01-1.53) 3

The Catecholamine Depletion Problem

The 2023 Society of Critical Care Medicine guidelines explicitly acknowledge the critical limitation: "In critically ill patients with depleted catecholamine stores, there is concern for hypotension and cardiac arrest" with ketamine 222. This is particularly relevant in prehospital settings where patients often present in extremis with:

  • Prolonged shock states
  • Severe trauma with ongoing hemorrhage
  • Sepsis with cardiovascular collapse
  • Cardiac arrest survivors

In these scenarios, ketamine's sympathomimetic effects paradoxically fail because they depend on endogenous catecholamine release—stores that are already exhausted.

No Mortality Benefit Despite Theoretical Advantages

Despite ketamine's theoretical benefits, no survival advantage has been demonstrated:

  • The 2023 SCCM guidelines state: "We suggest there is no difference between etomidate and other induction agents administered for RSI with respect to mortality" (conditional recommendation, moderate quality evidence) 222

  • A 2024 study of 1,457 traumatic brain injury patients found identical 30-day mortality (32.9% etomidate vs 33.8% ketamine, p=0.716) 4

  • Multiple meta-analyses confirm no mortality difference (OR 1.0,95% CI 0.83-1.21) 35

Etomidate's Favorable Hemodynamic Profile

Etomidate maintains superior hemodynamic stability in the peri-intubation period 22. The 2023 SCCM guidelines note: "Most studies demonstrated favorable peri-intubation hemodynamics with etomidate" 2. This is critical because peri-intubation hypotension is associated with organ dysfunction, prolonged mechanical ventilation, prolonged ICU stay, and increased mortality 22.

The Adrenal Suppression Red Herring

While etomidate's 11-beta-hydroxylase inhibition has historically raised concerns, the clinical significance remains unproven:

  • The 2023 SCCM guidelines acknowledge: "Whether etomidate-induced adrenal enzyme inhibition results in hypotension, increased vasopressor use, and increased mortality in the peri-intubation and postintubation period is unknown" 22

  • A Cochrane review of six studies (772 patients) showed no increased mortality with single-dose etomidate (OR 1.17,95% CI 0.86-1.60) 22

  • The guidelines conclude: "Because of the lack of evidence that etomidate-induced adrenal insufficiency causes negative clinical outcomes, additional research focused on this topic may be redundant" 2

Clinical Algorithm for Prehospital RSI Induction Agent Selection

Default to etomidate (0.3 mg/kg, or 0.15 mg/kg if hemodynamically compromised) for most prehospital RSI cases based on:

  1. Superior hemodynamic stability in critically ill patients
  2. Lower risk of post-intubation cardiovascular collapse
  3. Equivalent mortality outcomes
  4. Widespread availability and clinician familiarity

Consider ketamine (1-2 mg/kg) only in specific scenarios:

  • Post-cardiac arrest patients with adequate resuscitation (avoid if ongoing shock)
  • Severe reactive airway disease requiring bronchodilation
  • Patients with confirmed adequate hemodynamic reserve (SBP >140 mmHg, no vasopressor requirement)

Avoid ketamine in:

  • Septic shock or suspected catecholamine depletion
  • Hemorrhagic shock or ongoing bleeding
  • Any patient with SBP <100 mmHg or requiring vasopressors
  • Prolonged prehospital scene times with delayed resuscitation

Critical Pitfalls

The most dangerous misconception is that ketamine universally preserves hemodynamics through sympathomimetic effects. This assumption fails in the exact patient population most commonly requiring prehospital RSI—those in shock states with depleted endogenous catecholamines. The 2017 AAGBI guidelines note that while historical concerns about ketamine increasing intracranial pressure are unfounded, "the sympathomimetic effects may have disadvantages where anaesthesia is delivered after resuscitation from cardiac arrest or in patients with severe cardiac disease" 6.

Another pitfall is overweighting the theoretical concern about etomidate-induced adrenal suppression while ignoring the proven risk of ketamine-induced hypotension. The evidence clearly shows single-dose etomidate for RSI does not translate to clinically meaningful adrenal dysfunction or worse outcomes 222.

The prehospital environment amplifies these risks because providers have limited ability to rapidly correct hypotension, making the choice of a hemodynamically stable induction agent paramount. Etomidate's track record of cardiovascular stability, combined with equivalent mortality and intubation success rates, makes it the more defensible default choice for prehospital RSI 221.

References

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