What is the recommended dose of ketamine (anesthesia medication) for an adult patient with burns and no significant medical history for pain management?

Ketamine Dosing for Burn Pain Management in Adults

For adult burn patients without significant medical history, administer titrated intravenous ketamine at an initial dose of 1-2 mg/kg IV over 60 seconds, combined with a benzodiazepine (typically midazolam 2-5 mg IV) and short-acting opioids as needed for severe burn-induced pain during wound care and dressing changes. 1, 2, 3

Recommended Dosing Protocol

Initial Ketamine Administration

• Start with 1-2 mg/kg IV administered slowly over 60 seconds to minimize respiratory depression and enhanced vasopressor response 3
• The median effective dose in burn wound care studies is approximately 1.2 mg/kg (range 0.8-2.1 mg/kg) 4
• Lower doses (0.75 mg/kg mean) have proven effective when using nurse-driven protocols 5
• Rapid administration must be avoided as it increases risk of respiratory depression 3

Multimodal Analgesia Approach

• Always combine ketamine with other analgesics rather than using it as monotherapy 1, 2
• Administer IV midazolam (typically 2-5 mg) concurrently in nearly all cases (98% of procedures) to prevent dysphoric reactions during emergence 4
• Short-acting opioids (fentanyl preferred) should be available but may only be needed in 26% of cases when ketamine is used 4
• All medications must be titrated based on validated pain assessment scales to prevent under- or overdosing 1, 2

Preparation and Safety Considerations

Drug Preparation

• The 100 mg/mL concentration must never be administered IV without proper dilution 3
• Dilute with equal volume of Sterile Water, Normal Saline, or 5% Dextrose 3
• Use immediately after dilution 3

Critical Safety Monitoring

• Emergency airway equipment must be immediately available 3
• Continuous monitoring required: ECG, pulse oximetry, and blood pressure every 5 minutes during initial infusion 1
• Consider antisialagogue administration prior to induction due to potential for increased salivation 3

Burn-Specific Physiologic Considerations

Burn injuries create unique pharmacologic challenges that make titration essential: inflammation, hypermetabolism, and capillary leakage lead to hypovolemia, which increases the risk of adverse effects from analgesics and sedatives 1, 2. This is why fixed dosing without titration is particularly dangerous in burn patients.

Maintenance and Repeat Dosing

For Extended Procedures

• Additional increments of one-half to full induction dose can be repeated as needed 3
• Maintenance infusion at 0.1-0.5 mg/minute can sustain general anesthesia if required 3
• Higher total doses result in longer recovery times 3

Timing Considerations

• Ketamine is ideal for short-lasting burn pain during dressing changes and wound care 1
• Effects typically last 5-10 minutes with IV doses of 2 mg/kg 3
• Intramuscular route (9-13 mg/kg) produces 12-25 minutes of effect but is not preferred for procedural pain 3

Expected Outcomes and Adverse Effects

Efficacy

• Reduces opioid requirements by approximately 29% 5
• Reduces benzodiazepine requirements by approximately 20% 5
• 92% of patients report no unpleasant recall when properly combined with midazolam 4

Common Adverse Effects and Management

• Dysphoric reactions occur in approximately 6% of cases despite benzodiazepine co-administration 4
• Ketamine-induced hypertension occurs in 6% of cases and responds immediately to IV labetalol 4
• Purposeless or tonic-clonic movements may occur and do not indicate inadequate anesthesia or need for additional dosing 3
• Oversedation risk exists when combined with high-dose opioids 5

Critical Contraindications and Warnings

Avoid Concurrent Local Anesthetics

• Do not use ketamine within 4 hours of nerve blocks, fascial plane blocks, or local anesthetic infiltration 1
• Single-shot spinal blockade is acceptable given small local anesthetic doses 1
• Concurrent ketamine with other systemic analgesics is acceptable and common 1

Agents to Avoid in Acute Burn Phase

• Alpha-2 receptor agonists (dexmedetomidine) should be avoided in the acute phase due to hemodynamic effects 1, 2
• Note: One older study 6 suggested dexmedetomidine combinations, but current guidelines explicitly recommend against this in acute burns 2
• Insufficient evidence exists for IV lidocaine use in burn patients 1

Alternative Considerations

When Ketamine May Not Be First-Line

• For highly painful injuries or extensive procedures, general anesthesia may be more appropriate 1
• Inhaled nitrous oxide is useful when IV access is unavailable 1
• Non-pharmacological adjuncts (virtual reality, hypnosis) can reduce ketamine requirements when patient is stable 1, 2

Genitourinary Monitoring

• In chronic ketamine users, genitourinary pain has been reported 3
• Consider cessation if genitourinary pain develops with other urinary symptoms 3
• This is not typically relevant for acute procedural use in burns 3