What ketamine‑propofol (ketofol) bolus and infusion dosing regimen should be used for an average 70‑kg adult without severe cardiac or hepatic disease?

Ketamine-Propofol (Ketofol) Dosing for Procedural Sedation

For a 70-kg adult without severe cardiac or hepatic disease undergoing procedural sedation, use a 1:1 mixture of ketamine 10 mg/mL and propofol 10 mg/mL, administered as an initial bolus of 0.5-0.75 mg/kg of each agent (approximately 35-50 mg total of each drug), followed by incremental boluses of 0.25-0.5 mg/kg (approximately 10-20 mg of each) every 2-3 minutes as needed to maintain adequate sedation.

Recommended Dosing Regimen

Initial Bolus Dose

• Ketamine: 0.5-0.75 mg/kg (35-50 mg for 70-kg patient)
• Propofol: 0.5-0.75 mg/kg (35-50 mg for 70-kg patient)
• Administer over 1-2 minutes 1, 2

Maintenance Dosing

• Incremental boluses: 0.25-0.5 mg/kg of each agent (approximately 10-20 mg)
• Repeat every 2-3 minutes as needed for procedural requirements 1, 2
• Median total dose typically reaches 0.75 mg/kg of each agent 2

Preparation Method

The most practical approach is the single-syringe technique: mix equal volumes of ketamine 10 mg/mL and propofol 10 mg/mL in the same syringe, yielding a final concentration of 5 mg/mL for each component 1, 3, 2. This 1:1 ratio has been extensively studied and provides optimal balance between sedation depth, recovery time, and adverse event profile.

Clinical Evidence Supporting This Regimen

The 1:1 ketofol ratio demonstrates superior outcomes compared to alternative ratios or monotherapy:

• Efficacy: 96-98% procedural success rate without adjunctive sedatives 1, 2
• Recovery time: Median 14-15 minutes (range 5-50 minutes) 1, 2
• Onset: Rapid sedation within 1 minute 4
• Safety profile: Low incidence of respiratory depression (2.1-2.6% requiring bag-mask ventilation) 1, 2

The combination leverages propofol's rapid onset and smooth sedation with ketamine's analgesic properties and hemodynamic stability, while each agent mitigates the other's adverse effects 3, 5.

Infusion Alternative

For procedures lasting 5-20 minutes, a continuous infusion can be used as an alternative to intermittent boluses:

• Ketamine-to-propofol ratio: 1:4 for infusion
• Start with loading dose as above
• Maintain with continuous infusion titrated to effect 4

However, intermittent bolus dosing remains the preferred method for most emergency department procedures due to easier titration and predictable recovery 4, 2.

Critical Safety Considerations

Respiratory Monitoring

• Continuous pulse oximetry and capnography are essential
• Transient hypoxia occurs in approximately 2.6% of cases 2
• Airway repositioning may be needed in 3.5% of patients 2
• Have bag-valve-mask immediately available

Cardiovascular Effects

Ketofol provides hemodynamic stability superior to propofol alone. In high-risk patients, ketamine significantly reduces vasopressor requirements compared to propofol (9.6 vs 32.7 norepinephrine equivalents, P < 0.03) 6. This makes ketofol particularly advantageous in patients with borderline blood pressure.

Emergence Reactions

The 1:1 ratio minimizes ketamine-related emergence phenomena:

• Recovery agitation occurs in 3.6% of patients 1
• Only 1.8% require treatment (typically low-dose midazolam) 1
• Propofol's antiemetic properties (EC50 0.343 μg/mL) persist 30-40 minutes post-procedure 4

Common Pitfalls to Avoid

Do not use rapid bolus administration in elderly patients (>70 years). Reduce initial dose by 20-30% and administer over 3-5 minutes to prevent cardiorespiratory depression 7.

Avoid ratios greater than 1:3 ketamine-to-propofol for procedures lasting >20 minutes, as this results in delayed recovery due to ketamine accumulation 4.

Do not combine with additional benzodiazepines or opioids unless specifically needed, as this increases respiratory depression risk and prolongs recovery 8.

Ensure adequate fasting status when feasible, though ketofol's low emesis rate (0.9%) makes aspiration risk minimal 2.

Patient Satisfaction and Staff Acceptance

Both patients and healthcare providers report high satisfaction with ketofol:

• Median patient satisfaction: 10/10 1, 2
• Median physician satisfaction: 10/10 1, 2
• 97% of patients would choose the same method again 1

This regimen has been successfully used across 728 adult patients in prospective studies with consistent safety and efficacy outcomes 1.