Patient Outcomes After Failed Extubation
Abstract & Commentary
By David J. Pierson, MD, Professor Emeritus, Pulmonary and Critical Care Medicine, University of Washington, Seattle.
This article originally appeared in the October 2011 issue of Critical Care Alert. It was peer reviewed by William Thompson, MD. Dr. Thompson is Associate Professor of Medicine, University of Washington, Seattle. Drs. Pierson and Thompson report no financial relationships relevant to this field of study.
Synopsis: Failed extubation is more likely to occur in elderly patients with underlying chronic cardiac or pulmonary disease, and patients in whom it occurs have substantially worse clinical outcomes than those who do not require reintubation.
Source: Thille AW, et al. Outcomes of extubation failure in medical intensive care unit patients. Crit Care Med 2011;Jul 14. [Epub ahead of print]
In this prospective study carried out in a 13-bed French medical ICU, Thille and associates sought to determine the clinical characteristics and outcomes of patients who experienced extubation failure the requirement for reintubation within 72 hours of either planned or unplanned extubation. Ventilated patients were evaluated daily according to an established protocol, and all patients in the unit were included unless they underwent tracheotomy or had previously been reintubated. In keeping with accepted evidence-based standards, patients were considered for weaning and extubation when their overall medical condition had improved, their vital signs were stable, their gas exchange and support requirements were acceptable, they did not require excessive airway suctioning, and they were capable of initiating respiratory efforts. They then underwent a spontaneous breathing trial, which if successful was followed by extubation. Also included in the study were all patients who extubated themselves, or whose endotracheal tubes became dislodged during routine care. Criteria for reintubation were standardized, and noninvasive ventilation was not routinely used following extubation.
During the 1-year observational period, 340 adult patients were managed with invasive mechanical ventilation. Their mean age was 59 years and 66% were men. Median total durations of mechanical ventilation and ICU stay were 5 and 9 days, respectively; 60% of the patients survived to the weaning period and ICU mortality was 49%. After exclusion of patients who died on the ventilator and those undergoing tracheotomy, planned and unplanned extubations occurred in 168 and 31 patients, respectively. Extubation failure (requirement for reintubation because of respiratory failure, coma, or shock within 72 hours) occurred in 26 (15%) of the planned and in 20 of the unplanned extubations (48% of self-extubations and 100% of accidental extubations). When planned extubation failed, pneumonia occurred commonly (7/26, 27%) and subsequent mortality was high (13/26, 50%).
Patients who met weaning criteria, had successful spontaneous breathing trials, and were electively extubated, but who subsequently failed and had to be reintubated, had the same duration of ventilatory support prior to weaning, diagnoses, and illness severely as their counterparts who did not require reintubation. However, they were older (65 ± 16 vs. 56 ± 17 yr, P < 0.01) and were more likely to have underlying chronic cardiac or respiratory disease (65% vs. 39%, P = 0.02). Extubation failure occurred in 34% of all patients > 65 years old with chronic cardiac or respiratory disease, compared with only 9% of other patients (P < 0.01). Failure of both planned and unplanned extubation was associated with rapid worsening of daily organ dysfunction scores. Mortality was 10 times higher in patients with failed extubation than in those with successful planned extubation.
In keeping with findings from numerous other studies, the extubation failure rate in this series after patients fulfilled accepted weaning and extubation criteria was 15%. However, the important contributions of the current study are that: 1) the patients who failed planned extubation were not detectably different from those who did not require intubation with respect to illness severity, initial diagnoses, or duration of ventilatory support at the time of the attempt; 2) despite this lack of differences in the evidence-based assessments used to determine when extubation is appropriate, patients older than age 65 and those with underlying cardiac or respiratory disease were much more likely to fail; and, 3) once they failed, they did very poorly.
Although it is disheartening that the Simplified Acute Physiology II and Sequential Organ Function Assessment scores did not discriminate between successful and unsuccessful extubations, and that using accepted prediction and management practices on patients who were going to fail extubation could not be identified in advance, I find the results useful in at least one important respect. If the results of this study hold up with further investigations and clinical experience, we should consider extubation failure an important event in terms of prognosis when interacting with patients and families especially when the patient is older than 65 with cardiac and/or respiratory comorbidities. It is encouraging to clinicians and family members alike when a patient passes a spontaneous breathing trial and is initially weaned from ventilatory support after an episode of critical illness. However, when this progress is reversed over the next few days and invasive mechanical ventilation must be resumed, it illustrates the imprecision of our ability to predict how the patient will do, and suggests that the outlook may not be as favorable as we hoped.