What are the appropriate weight‑based intravenous doses of ketamine and propofol for rapid sequence intubation?

Ketamine and Propofol Dosing for Rapid Sequence Intubation

For RSI in critically ill adults, use ketamine 1-2 mg/kg IV or propofol 1.5-2 mg/kg IV as induction agents, with ketamine preferred in hemodynamically unstable patients due to its more favorable blood pressure profile.

Ketamine Dosing

Standard Induction Dose

• IV dose: 1-2 mg/kg administered slowly over 60 seconds 1
• FDA-approved range extends from 1-4.5 mg/kg, with 2 mg/kg producing 5-10 minutes of surgical anesthesia within 30 seconds 1
• The 2023 Society of Critical Care Medicine guidelines consistently reference ketamine dosing at 1-2 mg/kg across multiple studies 2

Dose Considerations

• Higher doses (>2 mg/kg) are associated with significantly increased adverse events including hypotension (OR 7.0), laryngospasm (OR 10.8), bradycardia (OR 7.5), and oxygen desaturation (OR 6.0) 3
• One study found 0.5 mg/kg ketamine combined with propofol 3 mg/kg improved intubation conditions, but this was in a non-critically ill population 4
• In shock states, maintain the 1-2 mg/kg range—registry data shows no association between ketamine dose and postintubation hypotension, suggesting dose reduction may not prevent hemodynamic deterioration 5

Critical Administration Points

• Administer slowly over 60 seconds to avoid respiratory depression and enhanced vasopressor response 1
• The 100 mg/mL concentration must be diluted before IV administration 1
• Consider antisialagogue pretreatment due to increased salivation 1

Propofol Dosing

Standard Induction Dose

• 1.5-2 mg/kg IV for RSI in critically ill patients
• The research evidence consistently uses 2-3 mg/kg in RSI protocols 4, 6
• Lower doses (1.5 mg/kg) may be appropriate in hemodynamically compromised patients, though evidence for dose-response relationship with hypotension is limited 5

Hemodynamic Considerations

• Propofol causes the most profound blood pressure decrease among induction agents 2
• In a 2026 RCT, propofol resulted in a median lowest MAP of 60 mmHg (48-72) versus 66 mmHg (55-79) with ketamine within 10 minutes, though the difference was not clinically sustained 7
• Cardiovascular collapse occurred in 33% of propofol patients versus 22% with ketamine 7

Comparative Evidence and Selection Algorithm

When to Choose Ketamine Over Propofol

• Hemodynamic instability or shock (any vasopressor use, MAP <65 mmHg, shock index ≥0.9)
• Sepsis or septic shock—propensity-matched data shows ketamine associated with less clinical hypotension (51% vs 73%) 2
• Trauma patients—multiple studies support ketamine 2 mg/kg in this population 2, 8

When Propofol May Be Acceptable

• Hemodynamically stable patients without shock
• Patients with adequate preload and normal cardiac function
• When ketamine is contraindicated (elevated intracranial pressure concerns are debated)

Important Caveats

The 2023 SCCM guidelines found no mortality difference between etomidate and other induction agents (including ketamine and propofol) with moderate quality evidence 2. However, this does not address the immediate peri-intubation hemodynamic stability that affects morbidity.

Conflicting hypotension data exists: Some registry studies show higher hypotension rates with ketamine versus etomidate (OR 2.7 in sepsis patients) 2, while propensity-matched sepsis data shows the opposite 2. The most recent 2026 RCT found ketamine reduced hypotension risk compared to propofol (RR 0.56) but without sustained clinical benefit 7.

Critical point: Neither ketamine nor propofol dose showed association with postintubation hypotension in large registry analysis, suggesting patient factors outweigh dose selection in determining hemodynamic outcomes 5. This challenges the common practice of empiric dose reduction in shock.

Practical Dosing Strategy

1. Default to ketamine 1.5 mg/kg IV in critically ill patients requiring RSI
2. Use propofol 1.5-2 mg/kg IV only in hemodynamically stable patients
3. Do not reduce doses below standard ranges based solely on shock state—no evidence supports benefit 5
4. Prepare vasopressors before induction regardless of agent chosen—cardiovascular collapse occurs in 22-33% of patients 7
5. Administer slowly over 60 seconds to minimize hemodynamic perturbation 1