LITERATURE REVIEW Factors affecting bronchodilator delivery in mechanically ventilated adults Arzu Ari and James B Fink ABSTRACT 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. Key words: Aerosol deposition • Bronchodilator • Drug delivery • Mechanical ventilation • Nebulizer • pMDI • Ventilator INTRODUCTION Inhaled bronchodilators are commonly administered to adults undergoing mechanical ventilation to relieve dyspnea and reverse bronchoconstriction. However, there are several 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 fac- tors. The lack of attention and knowledge given to these factors not only creates a significant proportion of the aerosol depositing in the ventilator circuits and artificial airways but also decreases the efficiency of Authors: Dr A Ari, PhD, RRT, PT, CPFT, Assistant Professor, Division of Respiratory Therapy, School of Health Professions, College of Health and Human Sciences, Georgia State University, Atlanta, GA 30302-4019, USA; JB Fink, Adjunct Professor, Division of Respiratory Therapy, School of Health Professions, Georgia State University, Atlanta, GA 30302-4019, USA Address for correspondence: A Ari, Division of Respiratory Therapy, School of Health Professions, College of Health and Human Sciences, Georgia State University, P.O. Box 4019, Georgia 30302-4019, USA E-mail: aari1@gsu.edu; arzuari@hotmail.com aerosol drug delivery. The purpose of this paper is to review the factors affecting bronchodilator delivery during mechanical ventilation and provide insights for optimizing aerosol delivery in these patients. SEARCH STRATEGY The studies reviewed in this paper were derived from searches of bibliographic databases including Cochrane, Pubmed, Medline, Cinahl and ScienceDi- rect. In order to combine terms relating factors affecting bronchodilator administration in adults, a broad search strategy was used (see Figure 1). Search terms used for this review are ‘bronchodilators or beta-agonist’ and ‘mechanical ventilation or mechanical ventilator’ and ‘aerosol devices or nebulizers or metered-dose inhalers’ and ‘adults’. Both in vitro and clinical trials in English were chosen. Studies published in foreign languages were excluded because of lack of transla- tions. The search identified 77 articles. The selection criteria consisted of in vitro and clinical trials involving 192  2010 The Authors. Journal Compilation  2010 British Association of Critical Care Nurses, Nursing in Critical Care 2010 • Vol 15 No 4