Factors affecting bronchodilator delivery in mechanically ventilated adults

Background: Bronchodilators are increasingly being used in patients undergoing mechanical ventilation. There are multiple factors that affect bronchodilator delivery during mechanical ventilation. These factors can be classified into three categories: ventilator-related factors, circuit-related factors and device-related factors. Aims: The purpose of this paper is to review in depth each of the factors affecting bronchodilator delivery during mechanical ventilation. Search strategies: A literature search was undertaken using several databases including Cochrane, Pubmed, Medline, Cinahl and Science Direct. The literature search, although limited to the English language, covered materials from 1985 to May 2009. Conclusion: Aerosolized bronchodilator delivery to mechanically ventilated patients is complex as a result of the multiple factors that affect the amount of aerosol deposited in the lower respiratory tract. When these factors are not carefully controlled and the optimum technique for aerosol delivery is not utilized, a greater proportion of the aerosol will deposit in the ventilator circuits and artificial airways decreasing the available dose to the patient. Attention to these factors and optimizing aerosol delivery techniques will help to reach therapeutic endpoints of bronchodilator therapy in patients receiving ventilatory support. Relevance to clinical practice: Bronchodilator delivery during mechanical ventilation is factor and technique dependent. A clear understanding of the factors affecting aerosol drug delivery during mechanical ventilation is very important in optimizing the efficiency of bronchodilator delivery in mechanically ventilated adults. Through the recommendations made in this paper, clinicians will be able to optimize both their technique and the therapeutic outcomes of aerosol drug delivery in patients receiving ventilator support.