Delivery of bronchodilators with metred-dose inhalers (MDI) in

mechanically ventilated patients: Should We Invest?

Sharon Lamb

• Intensive Care Unit, Aintree University Hospitals NHS Foundation Trust – currently considering metred-dose inhalers to deliver bronchodilators in mechanically ventilated patients

• Prompted by equipment change

• Literature review to establish evidence base to underpin decision making

• Pros and Cons

• Consider nursing implications

•Outline

• British Nursing Index

• CINAHL

• Cochrane Library

• HMIC

• Medline

• Web of Science

• Search strategy developed using thesaurus terms and natural language key terms

•Identifying the Evidence Base

• Ease of Administration

• Decreased Costs

• Reliable Dosing

• Freedom from Contanimation

• But in mechanical ventilation it deposits in the endotracheal tube and ventilator circuit making it inefficient.

• However evidence shows despite smaller doses reaching the lower lung significant bronchodilator effect is achieved.

•The Theory Underpinning Use of MDIs

Dhand and Tobin (1996)

• Device• Ventilator used• Ventilator Mode/Settings• Location in Circuit• Humidification• Density of inhaled gas• Spacer use impacts:

– Ventilator deposition– Lung deposition

• Patient Condition» Garner et al , 2002

•Key elements for success

• In Vitro testing of the use of MDI to deliver dry powder bronchodilators shows that 16.2% - 20% of drugs could be delivered to the patient (Everard, Devadason and Le Soeuf, 1996 and Fink et al 1999)

• Georgopoulos et al (2000) indicates that MDI achieves similar results to bronchodilators delivered by nebulizers at reduced dose

• Simplicity of use is cited by Hess (1991), Dhand (1996) and Georgopoulos (2000) and results from integration with the ventilator circuit.

The Evidence for MDI Use

• Georgopoulous et al, 2000 make an economic case for the use of MDI suggesting cost savings per year of $300,000 per year in a typical 700 bed hospital. Given the state of NHS finances this level of saving may be attractive to management!

• Nebulizer use can lead patient/ventilator dyssynchrony if the inline nebulizer exceeds the patients inspiratory flow rate, Beaty et al 1989.

The Evidence for MDI Use

• Garner et al (2002) found no significant change in respiratory mechanics or haemodynamics when comparing delivery by MDI or Nebulizer.

• Marik et al (1999) report that nebulizers deliver the highest dosage, however they do suggest the use of MDI produces equal if not better results.

• Training

• Experience, change management

• Time

•Using Nebulizers in Ventilated Patients

•Implications for Nursing

• In Vitro tests by Fink et al (1999) suggest that for optimum delivery humidification should not be used this is not a realistic option for patients in the intensive care unit where humidification is used to prevent damage of the airway mucosa (Lange and Finlay, 2000)

• The majority of articles cite reduced levels of infection a reason for MDI use, however they fail to detail evidence to justify this claim. It must therefore be discounted.

• Cost-effectiveness– Greek Study – translatable?– ICU organisation– Pharmaceutical costs

– Georgopoulos et al (2000)

•Conclusion

• There are many variables impacting delivery– Device– Equipment Used– Settings– Location in Circuit– Spacer– Staff Experience

• Literature base – evidence base is not new, the range of articles is from the late 80's to 2002.

•Conclusion

•References

• Beaty, C.D., Ritz, R.H, and Benson, M.S. (1989) Continuous in-line nebulizers complicate pressure support ventilation. Chest 96 pp.1360–1363.

• Dhand, R. and Tobin, M.J. (1996) Bronchodilator delivery with metered-dose inhalers in mechanically-ventilated patients. European Respiratory Journal. 9 pp.585-595.

• Everard, M.L., Devadason, S.G. and Le Souef, P.N. (1996) In vitro assessment of drug delivery through an endotracheal tube using a dry powder inhaler delivery system. Thorax 51 pp.75-77.

• Fink, J.B., Dhand, R., Grychowski, J., Fahey, P.J. And Tobin, M.J. (1999) Reconciling In Vitro and In Vivo measurements of aerosil delivery from a metred-dose inhaler during mechanical ventilation and defining efficiency enhancing factors. Am J Resp Crit Care Med 159 pp.63-68.

• Garner, S.S., Weist, D.B., Bradley, J.W. And Habib, D.M. (2002) Two administration methods for inhaled albutamol in intubated patients. Archives of Diseases in Childhood 87 pp.49-5

• Georgopoulos, D., Moulidi,E., Kondili, E. and Klimathianki, M. (2000) Bronchodilator deliverpy with metered-dose inhaler during mechanical ventilation. Critical Care 4 pp.227-234

• Hess, D. (1991) Aerosol bronchodilator delivery during mechanical ventilation. Nebulizer or inhaler?. Chest 100 (4) p.1103.

• Lange, C. and Finlay, W. (2000) Overcoming the adverse effects of humidity in aerosol delivery via presurised metered-dose inhalers during mechanical ventilation. Am J Resp Crit Care Med. 161 pp.1614-1618.