Effects of Albuterol Inhalation on the Work of Breathing during Weaning from Mechanical Ventilation

Abstract

The work of breathing is a major determinant of the success of weaning from mechanical ventilation. The aim of this study was to assess whether an inhaled bronchodilator could reduce the mechanical load on the respiratory muscles and diminish the work. For this purpose, 15 intubated patients in the process of weaning from mechanical ventilation inhaled the beta 2-agonist bronchodilator albuterol via a spacer device filled with 1 mg of the drug and connected to the endotracheal tube. During spontaneous breathing, the mean work of breathing diminished significantly after albuterol, from 9.35 +/- 1.05 to 8.33 +/- 1.13 J/min (p less than 0.01), and seven patients exhibited a decrease superior or equal to 15%. This decrease resulted from a marked reduction in lung and airway resistance, from 12.0 +/- 1.7 to 9.8 +/- 1.4 cm H2O.L-1.s (p less than 0.05). No significant changes were observed in the breathing pattern, intrinsic PEEP or arterial blood gas measurements after albuterol, and peripheral cardiovascular effects were not significant. In seven patients, we were able to compare the changes that occurred after albuterol in the work of breathing during weaning from mechanical ventilation with the changes in pulmonary function induced by albuterol after extubation, as assessed by the forced oscillation method. A close correlation was found between the two types of change, further indicating that the reduction in the work of breathing was more likely to occur in patients with the largest bronchodilating effect of albuterol at baseline.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchodilator delivery with metered-dose inhalers in mechanically-ventilated patients

“…Inspiratory work of breathing was found to decrease in 9 out of 10 mechanically-ventilated patients following nebulization of 1.8 mg of metaproterenol [56]. This reduction may help in weaning problem patients from mechanical ventilation [40]. In 15 intubated patients, MANCEBO et al [40] found a significant reduction in inspiratory work of breathing after administration of 10 puffs of albuterol with a MDI and spacer.…”

“…This reduction may help in weaning problem patients from mechanical ventilation [40]. In 15 intubated patients, MANCEBO et al [40] found a significant reduction in inspiratory work of breathing after administration of 10 puffs of albuterol with a MDI and spacer. This decrease was largely due to a marked reduction in lung and airway resistance.…”

“…Few investigators have examined the efficacy of bronchodilators in mechanically-ventilated patients [8,11,12,15,[38][39][40][41][42][43][44]. Early studies showed promising results following bronchodilator administration by a MDI [42][43][44], and yet the data were ignored for several years.…”

“…The potential for atrial and ventricular arrhythmias must be borne in mind when high doses of beta-agonists are given in critically ill patients [60,61]. Although most studies have reported no adverse effects following administration of albuterol with a MDI to mechanically-ventilated patients [8,10,11,[38][39][40][41], we observed a dose-dependent increase in heart rate, becoming significant after administration of a cumulative dose of 28 puffs [12]. CFCs, used as propellants in a MDI, have a short half-life (<40 s) in blood after administration of a MDI to healthy volunteers.…”

Weaning from mechanical ventilation

“…These "flow-by" or flow-triggered mechanisms have been compared to conventional demand-valve systems, and recent studies [58][59][60] have reported that flow-by systems, used either in CPAP or SIMV, are able to produce a significant decrease in respiratory work and other indices of inspiratory muscle effort when compared to the conventional demand-valve.…”