Responsiveness to intravenous administration of salbutamol in chronic obstructive pulmonary disease patients with acute respiratory failure.

Objective: In chronic obstructive pulmonary disease (COPD) patients with acute respiratory failure (ARF), bronchodilating agents administered by inhalation have, in general, little effect on dynamic hyperinflation and concurrent static intrinsic positive end-expiratory pressure (PEEPi,st). Since in COPD the severely obstructed segments of the lung may not be reached by inhaled medication, we reasoned that drug efficiency may be enhanced by intravenous administration of the agent. Design: Physiological study. Setting: Two four-bed surgical-medical ICUs of a university hospital. Patients: Fourteen COPD patients were studied within 36 h from the onset of ARF. Measurements and results: Static compliance (Cst,rs), minimal (Rmin,rs) and additional (ΔRrs) resistance of the respiratory system, and PEEPi,st were measured before and after intravenous administration of salbutamol. All patients had limitation of air flow before and after salbutamol administration. On average, after salbutamol there was a small, though significant, decrease in Rmin,rs (-9%), ΔRrs (-12%) and PEEPi,st (-8%). Conclusion: The changes in resistance and PEEPi,st after intravenous administration of salbutamol were too small to be of clinical significance.