Failure to recognize ventilator withdrawal potential may result in increased time on mechanical ventilation, length of stay, risk of complications such as ventilator associated pneumonia (VAP), mortality, and costs.1,2,3
Studies show that clinical evaluation has a low sensitivity for correctly identifying patients who are ready for successful weaning compared to protocolized weaning.([FOOTNOTE=Kollef, M. H., Shapiro, S. D., Silver, P., et al. A randomized, controlled trial of protocol-directed versus physician-directed weaning from mechanical ventilation. Crit Care Med. 1997;25(4):567-574.],[ANCHOR=],[LINK=]),([FOOTNOTE=Navalesi, P., Frigerio, P., Moretti, M. P., et al. Rate of reintubation in mechanically ventilated neurosurgical and neurologic patients: evaluation of a systematic approach to weaning and extubation. Crit Care Med. 2008;36(11):2986-2992.],[ANCHOR=],[LINK=])
One survey of intensivists using clinical judgment to assess the potential for discontinuation found a sensitivity of only 35% (6 of 17 patients who were successfully discontinued were identified) and a specificity of 79% (11 of 14 patients who failed discontinuation were identified).([FOOTNOTE=Stroetz, R. W., & Hubmayr, R. D. Tidal volume maintenance during weaning with pressure support. Am J Respir Crit Care Med. 1995;152(3):1034-1040.],[ANCHOR=],[LINK=])
Ventilator-associated pneumonia (VAP) is a relatively common complication in patients who receive prolonged mechanical ventilation.([FOOTNOTE=Cook, D. J., Walter, S. D., Cook, R. J., et al. Incidence of and risk factors for ventilator-associated pneumonia in critically ill patients. Ann Intern Med. 1998;129(6):433-440.],[ANCHOR=],[LINK=]),([FOOTNOTE=Fagon, J. Y., Chastre, J., Domart, Y., et al. Nosocomial pneumonia in patients receiving continuous mechanical ventilation. Prospective analysis of 52 episodes with use of a protected specimen brush and quantitative culture techniques. Am Rev Respir Dis. 1989;139(4):877-884.],[ANCHOR=],[LINK=])
In a prospective study of 567 patients, Fagon et al. found that the actuarial risk of VAP was 6.5% at 10 days, 19% at 20 days, and 28% at 30 days of ventilation.9
Mechanical ventilation is expensive and ventilator-associated complications can further increase the costs dramatically.([FOOTNOTE=Wunsch, H., Linde-Zwirble, W. T., Angus, D. C., Hartman, M. E., Milbrandt, E. B., & Kahn, J. M. The epidemiology of mechanical ventilation use in the United States. Crit Care Med. 2010;38(10):1947-1953.],[ANCHOR=],[LINK=]),([FOOTNOTE=Zimlichman, E., Henderson, D., Tamir, O., et al. Health care-associated infections: a meta-analysis of costs and financial impact on the US health care system. JAMA Intern Med. 2013;173(22):2039-2046.],[ANCHOR=],[LINK=])
Premature ventilator withdrawal can lead to airway loss, compromised gas exchange, aspiration, and inspiratory muscle fatigue.([FOOTNOTE=Gilstrap, D., & MacIntyre, N. Patient-ventilator interactions. Implications for clinical management. Am J Respir Crit Care Med. 2013;188(9):1058-1068.],[ANCHOR=],[LINK=]) Reintubation carries an approximately 7-fold higher risk for ventilator-associated pneumonia and an approximately 3-fold increased mortality risk.4
Patients who have to be reintubated are much more likely to die in the hospital.([FOOTNOTE=Epstein, S. K., Ciubotaru, R. L., & Wong, J. B. Effect of failed extubation on the outcome of mechanical ventilation. Chest. 1997;112(1):186-192.],[ANCHOR=],[LINK=]),([FOOTNOTE=Esteban, A., Alia, I., Gordo, F., et al. Extubation outcome after spontaneous breathing trials with T-tube or pressure support ventilation. The Spanish Lung Failure Collaborative Group. Am J Respir Crit Care Med. 1997;156(2 Pt 1):459-465.],[ANCHOR=],[LINK=]),([FOOTNOTE= Frutos-Vivar, F., Esteban, A., Apezteguia, C., et al. Outcome of reintubated patients after scheduled extubation. J Crit Care. 2011;26(5):502-509.],[ANCHOR=],[LINK=]),([FOOTNOTE=Rady, M. Y., & Ryan, T. Perioperative predictors of extubation failure and the effect on clinical outcome after cardiac surgery. Crit Care Med. 1999;27(2):340-347.],[ANCHOR=],[LINK=]),([FOOTNOTE=Vallverdu, I., Calaf, N., Subirana, M., Net, A., Benito, S., & Mancebo, J. Clinical characteristics, respiratory functional parameters, and outcome of a two-hour T-piece trial in patients weaning from mechanical ventilation. Am J Respir Crit Care Med. 1998;158(6):1855-1862.],[ANCHOR=],[LINK=])
Achieving adequate gas exchange is a primary criterion for weaning eligibility. Gas exchange is optimal when respiratory muscles are not overloaded and can complement the work of the mechanical ventilator to pull gases deep into the lungs.13 Multiple patient-specific factors, such as metabolic derangement, airway obstruction, or resistive or obstructive physiology, are responsible for the majority of respiratory muscle loading.13 However, clinicians should also consider other factors such as sedation and patient ventilator asynchrony that contribute to respiratory muscle weakness and therefore contribute to ventilator dependence.13
19. Esteban, A., Alia, I., Tobin, M. J., et al. Effect of spontaneous breathing trial duration on outcome of attempts to discontinue mechanical ventilation. Spanish Lung Failure Collaborative Group. Am J Respir Crit Care Med. 1999;159(2):512-518.
20. Esteban, A., Frutos, F., Tobin, M. J., et al. A comparison of four methods of weaning patients from mechanical ventilation. Spanish Lung Failure Collaborative Group. N Engl J Med. 1995;332(6):345-350.
21. Thille, A. W., Harrois, A., Schortgen, F., Brun-Buisson, C., & Brochard, L. Outcomes of extubation failure in medical intensive care unit patients. Crit Care Med. 2011;39(12):2612-2618.
22. Torres, A., Serra-Batlles, J., Ros, E., et al. Pulmonary aspiration of gastric contents in patients receiving mechanical ventilation: the effect of body position. Ann Intern Med. 1992;116(7):540-543.