Effect of inspiratory flow rate on β2-agonist induced bronchodilation in mechanically ventilated COPD patients

Abstract

Salbutamol delivered by MDI and spacer device induces significant bronchodilation in mechanically ventilated patients with chronic obstructive pulmonary disease, but the magnitude of the effect is not affected by the inspiratory flow rate. These results do not support flow rate manipulations when bronchodilators are administered during controlled mechanical ventilation.

Aerosol therapy in intensive and intermediate care units: prospective observation of 2808 critically ill patients

“…Nevertheless, a large body of work has evaluated optimal implementation of aerosol therapy in patients undergoing artificial ventilation in terms of practicability and safety, and has shown significant physiologic efficacy of several inhaled drugs in this setting [5][6][7][8][9][10][11]. Significant reductions in respiratory system resistance of ventilated patients have been demonstrated after delivery of bronchodilator using various nebulizer and metered dose inhaler (MDI) set-ups [6,12,13]. In ventilator-associated pneumonia, optimized nebulization set-ups such as a low inspiratory peak flow, increased inspiratory time, interrupted humidification and nebulizer placement upstream in the inspiratory limb seem to deliver inhaled antibiotics effectively to treat lung infections [14][15][16][17].…”

Administration d’aérosols médicamenteux au cours de la ventilation mécanique

“…La marge thérapeutique est très large avec ces molécules [35] : cela explique que la plupart des études ne retrouvent pas d'influence des conditions d'administration (mode d'aérosolisation, réglages du ventilateur…) sur l'efficacité des bêta-2-mimétiques au cours de la VM [38,39]. En effet, l'efficacité est très bonne pour des faibles quantités de médi-cament déposées au niveau bronchique, et une amélioration de la technique d'administration est sans réel intérêt.…”

Congress Abstract book

“…This was due to the lower preparation costs in MDIs, shorter time requiring for administering an aerosol treatment with MDI, and the additional costs of the filters required in nebulizer use. Although the use of a chamber device is mandatory, the most investigated in-line aerosol chambers (AeroVent, Monaghan Medical, N. Y., USA [4,5,6], and ACE Diemolding Healthcare Division, N. Y., USA [7,8,9,10]) fit only Y-shaped ventilator circuits and cannot be used with double in-line tubing systems. In these cases nebulizers show comparable performance to MDIs, at least for the delivery of bronchodilator therapy [11].…”

“…Bench studies suggest that inspiratory flow pattern affects the efficacy of aerosolized bronchodilators in mechanically ventilated patients [6,17]. This issue has been addressed by Mouloudi and coworkers from the University of Crete in a small series of manuscripts, with the latest being published in the current issue of Intensive Care Medicine [10]. The authors have investigated the effect of an end-inspiratory pause [7], tidal volume [8], flow pattern (square wave or decelerating) [9], and now the effect of the inspiratory flow rate [10] on the efficacy of aerosolized bronchodilators in mechanically ventilated patients.…”

“…First, the authors found with a remarkable consistency a reduction in PEEPi of about 20 % and a significant reduction in static and dynamic airway pressures of approximately 10 % after the administration of aerosolized salbutamol [7,8,9,10]. Second, the magnitude of the effect did not depend on the investigated parameter or on an end-inspiratory pause [7], tidal volume [8], flow pattern [9], the recently investigated inspiratory flow rate [10]. One might argue that the small patient numbers was insufficient to determine small differences between the various forms of administration.…”