What is the recommended ketamine (ketamine) dosing for conscious sedation in a 6-year-old pediatric patient weighing 70.14 pounds who requires fracture reduction?

Ketamine Dosing for Pediatric Fracture Reduction

For a 6-year-old child weighing 70.14 pounds (31.8 kg) requiring fracture reduction, administer ketamine 1.5-2 mg/kg IV (48-64 mg total) or 4 mg/kg IM (127 mg total) if IV access is unavailable, with continuous monitoring and airway management capabilities immediately available. 1

Weight-Based Dosing Calculation

• Patient weight: 70.14 pounds = 31.8 kg
• IV route (preferred): 1.5-2 mg/kg = 48-64 mg total dose 1
• IM route (if no IV access): 4 mg/kg = 127 mg total dose 1

The higher end of the IV dosing range (1.5-2 mg/kg) is significantly more effective than lower doses, with only 5.5% of patients requiring supplemental doses compared to 54% when using 1.0 mg/kg 1. This is critical for fracture reduction procedures where adequate initial sedation prevents the need for repeated dosing and prolonged procedure times.

Route Selection and Administration

• IV administration is preferred with onset of action in 30-96 seconds and duration of 10-15 minutes 1
• IM administration provides onset within 3-4 minutes if IV access is impractical, with similar recovery times of approximately 90 minutes 1
• Administer IV ketamine slowly over 1-2 minutes to minimize adverse effects 1

Consider Adding Midazolam

Add midazolam 0.05-0.1 mg/kg IV (1.6-3.2 mg for this patient) to reduce emergence reactions, particularly beneficial in children over 6 years old. 1

• The combination of ketamine/midazolam demonstrated superior efficacy compared to fentanyl/midazolam for orthopedic procedures in a well-designed randomized controlled trial of 260 children aged 5-15 years 2
• Midazolam reduces recovery agitation from 35.7% to 5.7% in children over 10 years old 1
• However, one Class I study showed that midazolam did not affect the incidence of emergence reactions when combined with ketamine 2

Despite mixed evidence on emergence reaction reduction, the ketamine/midazolam combination provides better overall sedation quality with fewer respiratory complications than alternative regimens 2.

Critical Safety Monitoring Requirements

Continuous monitoring is mandatory throughout the procedure: 1

• Oxygen saturation (maintain >93% on room air) 1
• Heart rate and blood pressure every 5 minutes 1
• Capnography when available 3
• Qualified personnel trained in pediatric airway management must be present 4

Expected Adverse Effects and Management

• Hypoxemia occurs in 1.6-7.3% of patients, typically transient and responsive to supplemental oxygen 1
• Bag-valve-mask ventilation required in approximately 2% of cases 1
• Mild recovery agitation in 17.6% of patients, moderate-to-severe in 1.6% 1
• Emesis without aspiration in 6.7% of cases 1

Recovery Expectations

• Average total sedation time: 75-78 minutes 1
• Average recovery time: 84 minutes (range 22-215 minutes) 1
• Patient should be observed until fully alert and ambulatory

Contraindications to Avoid

Do not use ketamine in patients with: 1

• Uncontrolled cardiovascular disease or hypertension
• Cerebrovascular disease
• Active psychosis
• Severe hepatic dysfunction
• Elevated intracranial or intraocular pressure

Ketamine causes dose-dependent increases in heart rate, blood pressure, and cardiac output through sympathetic nervous system stimulation 1.

Key Clinical Pitfalls

• Do not underdose: Starting with 1.0 mg/kg IV results in 54% of patients requiring additional doses versus only 5.5% with 1.5 mg/kg 1
• Have reversal agents ready: While ketamine has no specific reversal agent, flumazenil (0.01 mg/kg) should be available if midazolam is used 4
• Ensure adequate fasting status when possible, though ketamine preserves airway reflexes better than other sedatives 1
• Prepare for respiratory support: Have bag-valve-mask and suction immediately available, as 2% of patients may require assisted ventilation 1