April 2002 / Volume 47 / Number 4 / Page 483
IntroductionAs many as 20% of extubated patients require reintubation (ie, extubation failure) within 72 hours of extubation, with the exact prevalence depending on numerous factors. The pathophysiologic basis of extubation failure is often different from the cause of weaning failure. Extubation failure substantially prolongs the duration of mechanical ventilation, intensive care unit stay, and hospital stay, and substantially increases hospital mortality. Therefore, prediction of extubation outcome and prevention of extubation failure may be critically important. Unfortunately, standard weaning tests have not proven sufficiently accurate in predicting extubation outcome. New semi-objective measurements of cough strength and secretion volume can help identify patients at increased risk for extubation failure. It is important to note that mortality increases with reintubation delay, which indicates that clinical worsening may take place during the period without ventilatory support. Therefore, improved outcome may derive from rapid identification of patients at increased risk, followed by expeditious reinstitution of ventilatory support when extubation failure occurs.
Prevalence and Risk Factors for Extubation Failure
Causes of Extubation Failure
Outcome for Extubation Failure
Prediction of Extubation Failure
Treatment of Extubation Failure
There has been extensive study of determining patient readiness for weaning (liberation) from mechanical ventilation, of the best approach to accelerate the process of progressive withdrawal for patients who prove difficult to wean, and of the pathophysiologic causes underlying weaning intolerance. Yet once ventilatory support is no longer needed, the clinician must address a different problem: can the patient tolerate extubation (ie, removal of the translaryngeal endotracheal tube [ETT])? The process and outcome of extubation has received increasing attention, with clinical investigators focusing on numerous aspects of extubation failure, including prevalence, risk factors, pathophysiology, prognosis, predictors, and strategies for prevention. Extubation failure can be defined as the need for reinstitution of ventilatory support, usually manifested as the need for reintubation. Numerous factors limit the study of this outcome, but the most important consideration may be the inability to recognize weaning failure and extubation failure as distinct and separate entities. In fact, recent research clearly indicates that those are discrete processes with distinct pathophysiologic causes and unique outcomes.