Purpose: To evaluate the effects of sedation with sufentanil on respiratory drive, respiratory pattern, and gas exchange of critically ill patients during pressure support ventilation.
Methods: In this prospective observational cohort study, we observed 12 adult patients receiving partial ventilatory support for acute respiratory failure. Each subject received a continuous infusion of sufentanil at 0.2 to 0.3 micro g x kg(-1) x hr(-1) to obtain a modified Ramsay sedation score between 2 and 3. In basal conditions and at variable distance from the beginning of the sufentanil infusion (10', 30', 60', 120', 24 hr) we evaluated gas exchange, hemodynamic variables, respiratory rate (RR), tidal volume (TV), respiratory pattern, respiratory drive (P0.1) and inspiratory impedance of the respiratory system [P0.1/TV/inspiratory time (Ti)].
Results: The continuous iv administration of 0.2 to 0.3 micro g x kg(-1) x hr(-1) of sufentanil resulted in the desired level of sedation. No significant heart rate, heart rhythm and blood pressure changes were observed. Sufentanil infusion did not affect TV, minute volume, Ti/inspiratory duty cycle, RR, P0.1, P0.1/TV/Ti and gas exchange did not change significantly over the study period.
Conclusion: A continuous infusion of sufentanil induces "awake" sedation with no detectable effects on respiratory variables in critically ill patients during partial ventilatory support.