Dexmedetomidine and ketamine sedation for muscle biopsies in patients with Duchenne muscular dystrophy.

BACKGROUND

Duchenne muscular dystrophy (DMD) possesses many potential challenges for anesthetic care. Invasive and noninvasive procedures with corresponding sedation or general anesthesia are frequent and necessary for affected patients. There remains a need for a better agent or agents for procedural sedation in patients with comorbid diseases. This study prospectively evaluated a combination of ketamine with two different doses of dexmedetomidine for sedation during muscle biopsy in patients with DMD.

METHODS

Dexmedetomidine 1.0 or 0.5 μg·kg(-1) was administered as a loading dose over 3 min followed by a continuous infusion of 1.0 or 0.5 μg·kg·h(-1). Ketamine (1 mg·kg(-1)) was administered along with the dexmedetomidine loading dose. As the procedure commenced, additional doses of ketamine (0.5 mg·kg(-1)) were administered as needed. Sedation scores, hemodynamic data, operative times, and recovery times were recorded.

RESULTS

The study cohort included a total of 53 bicep, deltoid, or anterior tibialis muscle biopsies in 19 boys including 24 in the dexmedetomidine 1.0 μg·kg(-1) group and 29 in the dexmedetomidine 0.5 μg·kg(-1) group. Mean age and weight were 9.7 ± 1.4 years and 33.3 ± 7.7 kg in the dexmedetomidine 1.0 μg·kg(-1) group and 8.8 ± 1.8 years and 30.2 ± 10.8 kg in the dexmedetomidine 0.5 μg·kg(-1) group. No significant changes in blood pressure were noted. A decrease in heart rate (HR) occurred after the loading dose of dexmedetomidine in both groups. The HR was significantly lower in the dexmedetomidine 1.0 μg·kg(-1) group compared with the dexmedetomidine 0.5 μg·kg(-1) group. Total recovery time to discharge was significantly shorter in the dexmedetomidine 0.5 μg·kg(-1) group than the dexmedetomidine 1.0 μg·kg(-1) group (146 ± 65 vs 174 ± 58 min; P = 0.03), although the total ketamine dose was significantly greater in the dexmedetomidine 0.5 μg·kg(-1) group (3.7 ± 1.0 vs 2.0 ± 0.5 mg·kg(-1); P < 0.01). There were no episodes of apnea or hypoventilation; however, a jaw thrust was needed in one patient in the dexmedetomidine 1.0 μg·kg(-1) group.

CONCLUSION

The combination of dexmedetomidine and ketamine is safe and effective for moderately painful procedures with limited respiratory and cardiovascular effects in a high-risk patient population. Dexmedetomidine 0.5 μg·kg(-1) as a loading dose with ketamine followed by a continuous infusion of dexmedetomidine at 0.5 μg·kg(-1) ·h(-1) achieved an adequate sedation level with shorter total recovery times in the perioperative unit compared with a higher dose regimen of dexmedetomidine (1.0 μg·kg(-1) loading dose followed by an infusion at 1.0 μg·kg(-1) ·h(-1)).