Ketamine Dosing for Intubation
For endotracheal intubation, ketamine should be administered at a dose of 1-2 mg/kg intravenously, with careful consideration of the patient's hemodynamic status. 1, 2
Standard Dosing Recommendations
- The FDA-approved intravenous dose of ketamine for induction of anesthesia ranges from 1 mg/kg to 4.5 mg/kg, with 2 mg/kg being the average dose required to produce 5-10 minutes of surgical anesthesia 1
- For rapid sequence intubation (RSI) in critically ill adults, the recommended dose is 1-2 mg/kg IV 2, 3
- Ketamine should be administered slowly over 60 seconds to prevent respiratory depression and enhanced vasopressor response 1
Special Patient Populations
- In hemodynamically unstable patients (e.g., multiple trauma, septic shock), consider using the lower end of the dosing range (1 mg/kg) to minimize the risk of hypotension 2
- For patients with septic shock, a combination of ketamine 0.5 mg/kg plus lidocaine 1 mg/kg has shown lower incidence of post-intubation hypotension compared to ketamine full-dose (1 mg/kg) 4
- Higher doses of ketamine (>2 mg/kg) have been associated with increased odds of adverse events including hypotension, laryngospasm, bradycardia, oxygen desaturation, and failed airway 5
Administration Technique
- Administer ketamine as part of a rapid sequence induction protocol with neuromuscular blockade 2
- Consider pre-treatment with an antisialagogue prior to ketamine administration due to the potential for increased salivation 1
- Have vasoconstrictors (e.g., ephedrine or metaraminol) immediately available to treat any hypotension 2
Monitoring and Safety Considerations
- Continuously monitor vital signs in patients receiving ketamine, including heart rate, blood pressure, and oxygen saturation 3, 6
- Emergency airway equipment must be immediately available when administering ketamine 1
- Ketamine causes a dose-dependent increase in heart rate, blood pressure, and cardiac output through stimulation of the sympathetic nervous system 3
Potential Adverse Effects
- Ketamine may cause transient increases in blood pressure and heart rate due to sympathetic stimulation 3
- Post-intubation hypotension has been reported in 18.3% of emergency department patients receiving ketamine for RSI 2
- Laryngospasm is a rare but potential complication (0.9-1.4%) 7
Alternative Approaches
- For patients at high risk of hemodynamic instability, consider a ketamine/propofol admixture (0.5 mg/kg of each) as an alternative to standard ketamine dosing 8
- In patients with restlessness or trismus preventing intubation, ketamine at 2 mg/kg IV has been shown to improve intubation success rates 9
- For medication-assisted preoxygenation in agitated patients prior to RSI, ketamine can be administered at 1 mg/kg with additional 0.5 mg/kg doses until a dissociative state is achieved 2
Remember that while these guidelines provide a framework for ketamine administration during intubation, the drug should be administered by or under the direction of physicians experienced in general anesthetics, airway management, and ventilation 1.