Sedation during noninvasive mechanical ventilation with dexmedetomidine or midazolam: A randomized, double-blind,...

Effective noninvasive mechanical ventilation (NIV) requires a patient to be comfortable and in synch with the ventilator, for which sedation is usually needed. Choice of the proper drug for sedation can lead to improved clinical outcomes.

The aim of this study was to compare the effectiveness of dexmedetomidine and midazolam on sedation and their effects on hemodynamics and gas exchange.

In this randomized, double-blind study, intensive care unit patients with acute respiratory failure due to acute exacerbations of chronic obstructive pulmonary disease undergoing NIV were equally randomized to receive a loading dose of 1 μg/kg IV dexmedetomidine or 0.05 μg/kg midazolam over 10 minutes followed by a maintenance infusion of 0.5 μg/kg/h dexmedetomidine (group D) or 0.1 mg/kg/h midazolam (group M). The following parameters were measured by a blinded clinician at baseline and 1, 2, 4, 6, 8, 12, and 24 hours after the loading dose was administered: Ramsay Sedation Score (RSS), Riker Sedation-Agitation Scale (RSAS), Bispectral Index (BIS), arterial blood gases, and vital signs. A second blinded investigator determined dosing changes according to the outcome of maintaining a target sedation level of RSS 2 to 3, RSAS 3 to 4, and BIS >85.

A total of 45 patients were assessed for enrollment in the study; 4 did not meet the inclusion criteria and 1 refused to participate (men/women 19/21; mean age 58/60; all patients were receiving bronchodilators, steroids, antibiotics, and mucolytics). In both groups (n = 20), RSS significantly increased and RSAS levels and BIS values significantly decreased after the loading dose, compared with baseline (P < 0.05). RSS levels were significantly lower beginning at 4 hours in group D compared with group M (P < 0.05). RSAS levels were not significantly different between the 2 groups in the first 8 hours. However, RSAS levels were significantly higher at 8 hours after the loading dose was administered in group D compared with group M (P < 0.01). BIS was significantly higher in group D throughout the study period (P < 0.05). Respiratory rates and gas exchange values were not significantly different between the Accepted for publication April 7, 2010. 2 groups. The number of times a change in infusion dose was needed was significantly lower in group D (2 patients with 1 change each) than in group M (3 patients with 1 change, 1 patient with 2 changes, and 3 patients with 3 changes each) (P < 0.01).

Dexmedetomidine and midazolam are both effective sedatives for patients with NIV. Dexmedetomidine required fewer adjustments in dosing compared with midazolam to maintain adequate sedation.