Inhaled Bronchodilator Therapy in Mechanically Ventilated Patients

This is the authors' abstract. We don't add key points for this paper.

Therapeutic aerosols are commonly used in mechanically ventilated patients, mainly to deliver bronchodilator drugs. Because ventilator-supported patients often receive several different classes of medications parenterally, the inhaled route of administration is particularly useful as an alternate route for drug delivery. Both nebulizers and metered-dose inhalers (MDIs) can be adapted for use in ventilator circuits. Traditionally, nebulizers have been used to deliver bronchodilators, antibiotics, and surfactant in mechanically ventilated patients, whereas MDIs chiefly have been used to deliver beta-adrenergic and anticholinergic bronchodilators (1). In the past, the combination of an MDI with an elbow adapter was considered to be ineffective (2) due to aerosol impaction in the ventilator circuit and endotracheal tube (3). However, recent studies (4‐6) have clearly established the efficacy of MDIs for delivering bronchodilators in mechanically ventilated patients, with the caveat that the technique needs to be carefully executed. With a better understanding of the many factors influencing aerosol delivery and deposition in mechanically ventilated patients, it is possible to provide a scientific basis for inhaled bronchodilator therapy in these patients. FACTORS INFLUENCING LOWER RESPIRATORY TRACT DEPOSITION OF AEROSOL In mechanically ventilated patients, the efficiency of aerosol delivery to the lower respiratory tract depends on several factors that are not concerns in ambulatory patients (7). Important determinants of aerosol deposition in ventilator-supported patients include the delivery system, particle size, characteristics of the ventilator circuit, ventilator mode, and patient-related factors. The effect of each factor on aerosol delivery is difficult to elucidate because of the large number of variables involved. Therefore, several investigators have conducted in vitro studies to define each variable’s influence on aerosol delivery with mechanical ventilators.