SAN FRANCISCO – Mechanically ventilated patients in the intensive care unit (ICU) have poorer outcomes if extubated during the night instead of during the day, finds a retrospective cohort study reported at an international conference of the American Thoracic Society.
Overall, 20.1% of the nearly 98,000 adult patients studied were extubated during nighttime hours, between 7:00 p.m. and 7:00 a.m., according to data presented in a session and a related press conference.
Compared with patients extubated during daytime hours, patients extubated during nighttime hours had higher rates of ICU and hospital death, with the absolute difference ranging from 1.0% to 5.1%. Additionally, among those mechanically ventilated for at least 12 hours, nighttime extubation was associated with an absolute 2% increase in the risk of reintubation.
“I think this is the first large-scale study that looks at a practice that, although not as common as we thought it was, is still done about a fifth of the time and even with decreasing rates, is not a rare practice on our units,” commented lead author Dr. Hayley B. Gershengorn of the department of medicine (critical care) and the Saul R. Korey department of neurology at the Albert Einstein College of Medicine, New York.
“As we have increasing staffing [overnight] and maybe an increasing push to move people through our ICUs, we need to probably take some care because although we can’t demonstrate a causal link, it is quite concerning, this consistent finding of increased mortality and reintubation in these folks,” she said.
There are several possible reasons for the observed heightened risks of death and reintubation with nighttime extubation that could not be fully explored in the study, Dr. Gershengorn said.
“We were not able to identify the indication for extubation or discontinuation of mechanical ventilation. So one of the concerns that we have is that it’s probably more common that folks unintentionally extubate themselves or someone unintentionally extubates them overnight, when staffing is less,” she explained. “The other part, which we tried to adjust for but we don’t have perfect data on, is what is the staffing overnight,” including factors such as the ratio of nurses to patients and how many units an intensivist is covering, not just whether he or she is present.
“In terms of the reintubation risk being higher in the [group with longer duration of mechanical ventilation], the question I have is whether or not there is less comfort with somebody looking less well when there is less staff around, and whether or not there may be a quicker trigger to reintubate them if they don’t look so great,” she said.
The majority of intubated patients are unlikely to improve enough physiologically to prompt nighttime extubation rather than waiting until daytime, according to Dr. Gershengorn. But there are at least two groups whom clinicians might want to extubate at night.
One group is those who underwent elective surgery during the day. “They are waiting to come out of anesthesia, and the plan is to discontinue mechanical ventilation at the time that that occurs,” she explained. Another group is those who are agitated on the ventilator, require more sedation than usual, and suddenly awake at night. “These patients are really hard to keep comfortable. I can [sedate them] again and try this problem all over again tomorrow morning, or I can just bite the bullet and pull the tube out,” she said.
The investigators analyzed data from the Project IMPACT critical care medicine database, in which data are prospectively collected for benchmarking purposes. In all, they studied 97,844 mechanically ventilated adults from 165 medical and surgical ICUs across the United States between 2000 and 2009.
Results showed that nighttime extubation was more common among elective surgical patients, those coming from the operating room or a postanesthesia care unit, and those mechanically ventilated for less than 12 hours.
In a finding that Dr. Gershengorn described as surprising, there was a temporal trend by which the adjusted proportion of extubations performed at night actually decreased in more recent years during the study period.
The investigators next looked at outcomes among 10,279 propensity-matched pairs of patients, one member of the pair having been extubated during the night and the other having been extubated during the day.
Among those mechanically ventilated for less than 12 hours, nighttime extubation was associated with higher ICU mortality (5.6% vs. 4.6%; P = .025) and hospital mortality (8.3% vs. 7.0%; P = .014). Findings were inconsistent for length of stay, with nighttime extubation associated with a shorter ICU stay but a longer hospital stay.