Weaning from Mechanical Ventilation

Abstract

The physician concerned with weaning a patient from mechanical ventilation must address three important questions: (a) when is it appropriate to initiate the weaning process? (b) which of the many weaning strategies is most efficacious? and (c) what is the sensitivity and specificity of certain weaning response parameters in defining weaning success or failure? Each of these topics is addressed below. Questions concerning the readiness of patients for weaning from mechanical ventilation are dealt with in the literature on weaning; Yang and Tobin have recently provided a detailed account on this issue [33]. The efficacy of different weaning strategies remains a topic of considerable debate which has yet to be resolved. Regardless of the physician’s own bias, familiarity with certain pitfalls associated with individual weaning techniques is mandatory. Finally, the definitions of weaning success and failure vary widely from study to study. This in turn affects the reported sensitivities and specificities of weaning parameters. To resolve some of the confusion surrounding this topic it may be useful to view weaning from mechanical ventilation as a process during which the physician can evaluate the load response of a patient’s ventilatory pump. In this respect weaning is analogous to exercise testing in its goal to characterize the performance capacity and endurance of the cardiopulmonary systems and to identify weak links in these systems on the basis of physiologic responses [13].