PURPOSE: Dexmedetomidine is a lipophilic alpha-2 agonist which sedates as a result of its action upon the locus caeruleus, the predominant noradrenergic nucleus in the brain. This pharmacologic action produces a unique profile: patients remain arousable despite being sedated, and there is little of the respiratory depression that is commonly encountered with most other sedating agents used for procedures. This profile makes it an appealing drug for sedation of patients with pulmonary compromise undergoing bronchoscopy. This application, however, had not been studied until this clinical trial.
METHODS: Patients with pulmonary compromise were prospectively enrolled and informed consent was obtained for this IRB-approved study. Dexmedetomidine was administered at 1.0 mg/kg/hr for 30 min before the procedure and continued throughout the bronchoscopy. Small doses of midazolam and fentanyl were given immediately prior to insertion of the bronchoscope and as needed subsequently. Drug requirements, sedation scores, vital signs and physiologic responses were recorded until discharge.
RESULTS: Ten patients with moderate to severe pulmonary compromise were enrolled. Mean age was 68 (range, 47-76). Mean FEV1 was 45±16% of predicted. Mean DLCO was 53±15%. Bronchoscopy lasted 23 ± 16 minutes. Results and the sedation scales are shown in Graph 1. The mean dose of midazolam was 2.2 ±1.7 mg and of fentanyl was 43±56 mcg. No patient exhibited marked hypotension or hypertension, bradycardia, apnea or desaturation during the procedure or during recovery. No procedure was terminated because of medication side-effects. Individual data for all monitored vital signs are shown in Graph 2.
CONCLUSION: This study of dexmedetomidine in patients at high risk for respiratory complications demonstrates efficacy. Doses of the adjunct medications midazolam and fentanyl were minimal. Hypertension and tachycardia normally caused by bronchoscopy were not observed. Known side-effects of dexmedetomidine were not problematic.
CLINICAL IMPLICATIONS: This study demonstrates utility of dexmedetomidine sedation for high-risk pulmonary patients undergoing bronchoscopy. The data are sufficient to warrant additional prospective, randomized trials comparing dexmedetomidine sedation for bronchoscpy to conventional conscious sedation using only midazolam and fentanyl.
DISCLOSURE: Wissam Abouzgheib, No Product/Research Disclosure Information; University grant monies Cooper University Hospital received dexmedetomidine vials used for this research purposes free of charge from Hospira, Inc. Cooper Hospital also received the amount of 12,000 dollars to support this research protocol