ABSTRACT & COMMENTARY

Should Patients with Acute Respiratory Failure be Extubated at Night?

By David J. Pierson, MD, Editor

SYNOPSIS: In this retrospective study of extubation outcomes in five ICUs at a single medical center, patients extubated at night had no increase in adverse events and their mortality rates and lengths of ICU stay were lower. However, these results were likely affected by the high proportion of post-cardiac-surgery patients in the nighttime extubation group.

SOURCE: Tischenkel BR, et al. Daytime versus nighttime extubations: A comparison of reintubation, length of stay, and mortality.
J Intensive Care Med 2014; Apr 24. [Epub ahead of print.]

This is a retrospective study of extubation outcomes in the five ICUs of Montefiore Medical Center in New York during a recent 23-month period. Institution-wide, respiratory therapist-driven weaning and extubation protocols (incorporating physician input for marginal data or clinician concern) and 24/7 intensivist ICU presence were in place at the time of the study. Once patients were clinically improved, with spontaneous respiratory rate and required inspired oxygen fraction and positive end-expiratory pressure requirements in an acceptable range, and were hemodynamically stable with manageable respiratory secretions and acceptable arterial blood gas results, they underwent a 30-minute spontaneous breathing trial with added pressure support to keep their tidal volumes at least 5 mL/kg ideal body weight. If the results of this trial were satisfactory according to standardized objective and subjective criteria, the patients were extubated. Outcomes with respect to the need for reintubation, hospital length of stay, and mortality were compared for patients extubated between 7 p.m. and 7 a.m. (coinciding with shift changes for nurses, respiratory therapists, and intensivists) vs those extubated during the day.

More than twice as many patients (n = 1555) had been extubated during daytime hours as during the night (n = 685). Reintubation occurred twice as frequently among patients extubated during the day (7.7%) as among those extubated at night (3.8%; odds ratio 0.5; P = 0.01). Total hospital length of stay was significantly shorter for patients extubated at night (P = 0.002; actual data not provided), despite adjustment for demographic factors, Elixhauser Comorbidity Measure, and other variables. Although it was not statistically significant, there was a trend toward lower mortality among patients extubated at night. The authors conclude that a practice of delaying extubation until morning in patients who meet weaning and extubation criteria during the night is not supported by their results, and that patients should be extubated as soon as these criteria are met.

COMMENTARY

A number of recent studies pertain to the context and findings of the current report. First, outcomes for patients admitted at night have been shown to be worse in comparison with patients admitted during daytime hours, at least in some institutions. The risk for medical errors is higher at night. And adding the in-unit presence of a qualified intensivist has been shown to improve patient outcomes. These findings suggest that the results of critical care during the night may not be as good as those during the day, at least in some settings.

However, although the prediction of successful weaning and extubation are not perfect, many studies have shown improved success rates (including getting patients extubated sooner) with the use of evidence-based criteria and standardized protocols. Numerous studies have shown associations between shorter durations of mechanical ventilation and improved ICU and hospital outcomes, and it is well established that ventilator-associated pneumonia and other ventilator-associated complications are strongly related to the duration of endotracheal intubation. Thus, it is reasonable to reconsider the traditional approach of many intensivists not to extubate patients recovering from acute respiratory failure during the nighttime hours.

On the surface, this study would appear to refute that time-honored, cautious approach. However, despite the authors’ attempts to reduce confounding by diagnosis, severity of illness, and other factors, I am concerned by the differences between the patients who were extubated at night and those extubated during the day in this study. More than half of all the study patients (1171 of 2240) were managed in a cardiac surgery ICU (CSICU), and patients in these units comprised 81.8% of all those who were extubated at night. As the authors state, in their CSICUs, "a protocol is set in place so that patients are to be extubated within 6 hours of the end of their surgery." They acknowledge that patients undergoing elective cardiac surgical procedures, which typically begin in the morning, "would undergo extubation during the study’s defined nighttime hours (after 7 p.m.)," and, in fact, the CSICUs had a disproportionate number of extubations between 7 p.m. and 10 p.m. compared to the other units.

Patients ventilated after cardiac surgery have acute respiratory failure mainly due to anesthesia, and studies have shown improved outcomes with early extubation in such patients. Retrospective studies are inherently limited in terms of establishing causal relationships, and despite the authors’ statistical adjustments, I think their inability to associate nighttime extubation with any unfavorable consequences could be due to the marked differences between the patients who were extubated at night vs during the day.

However, this study shines useful light on the long-standing debate as to whether extubation should be deferred until the next morning when a patient first meets criteria during the evening or nighttime hours. The table provides a reasonable approach to this question. It is based more on experience and common sense than on explicit published evidence, but is generally consistent with the results of this study and others in the literature.