Dexmedetomidine facilitates induction of noninvasive positive pressure ventilation for acute respiratory failure in patients with severe asthma

Noninvasive positive pressure ventilation (NPPV) has been reported to be effective for acute respiratory failure in patients with severe asthma. Although NPPV requires less sedative than invasive mechanical ventilation, agitated patients with severe asthma should be given the minimum sedation necessary to facilitate the induction of NPPV. Two asthmatic patients (a 65-year-old man and a 32-year-old woman) separately presented to the intensive care unit with exacerbating respiratory failure. We initiated NPPV using bilevel positive airway pressure (PAP) ventilation. The ventilation was initially set as an inspiratory PAP of 15 cmH₂O and an expiratory PAP of 4 cmH2O. Because they seemed too agitated to tolerate the mask ventilation, dexmedetomidine was administered intravenously, at 3 μg·kg⁻¹·min⁻¹ for 10 min, followed by a continuous infusion at 0.2–0.6 μg·kg⁻¹·min⁻¹. One hour after the institution of NPPV, the patients were well cooperative with the mask ventilation and the respiratory symptoms had markedly improved. While the Ramsay sedation scale was maintained at 2 or 3 during the continuous dexmedetomidine infusion, we successfully weaned the patients from NPPV by reducing the inspiratory PAP. Dexmedetomidine helped the agitated patients cooperate with mask ventilation without inducing respiratory depression. We conclude that dexmedetomidine may be a valuable sedative to facilitate the induction of NPPV. This case report was presented in part at the 81st clinical and scientific congress of the International Anesthesia Research Society, Orlando, Florida, March 23–27, 2007.