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Do "Sedation Vacations" Really Speed Weaning From Mechanical Ventilation?
Daily interruptions of sedation ("sedation holiday" or "sedation vacation") became the standard of critical care for weaning from mechanical ventilation in ICUs around the world after J.P. Kress et al's landmark 2000 New England Journal of Medicine paper showing daily sedation interruptions freed ~64 patients from ventilators an average of 2 days sooner, and shortened ICU stays by 3.5 days, without safety risks, compared to ~64 patients getting usual care.
But nurses tending to undersedated, agitated patients grumbled (and turned up the drips after rounds and overnight). Mental health and outcomes researchers worried about psychological harm from unsedated patients. And subsequent randomized trials did not consistently replicate Kress et al's impressive findings: a 2011 meta-analysis of 5 trials of sedation interruptions did not show sedation holidays reduced ventilator-days among 699 patients, although it did seem safe (no excess self-extubations) and led to fewer tracheostomies.
Protocolized sedation titration (to objective measures of sedation) also hastened ventilator weaning in early trials, but with widely varying results in other published studies. Clearly, answering this question more definitively was a job for [cue superhero music] the Canadian Critical Care Trials Group.
What They Did
Authors randomized 430 critically ill adults on mechanical ventilation in 16 ICUs in Canada and the U.S. to daily sedation interruptions, or none. All patients received protocolized sedation titration (by nurses trained to use light sedation).
What They Found
Sedation interruptions did not improve any measured outcome. There was no difference in median time to successful extubation: 7 days in each group. Nor did sedation interruptions improve ICU stay (median 10 days in both groups) or hospital stay (20 days in both). Also:
- Sedation interruptions actually resulted in increased total daily doses of midazolam and fentanyl, mainly because patients in this arm required more frequent and larger medication boluses after their interruptions in sedation.
- Ten patients in the sedation-interruption group pulled out their endotracheal tubes, compared to 12 in the continuous sedation group (non-significant).
- There was no difference in identified delirium (53% vs 54%).
- Nurses caring for patients receiving sedation interruptions perceived they were working harder, on a 10-point visual analog scale (4.2 vs. 3.8).
What It Means
Why didn't sedation holidays -- a cornerstone of care for mechanically ventilated patients -- make any difference in this well-conducted trial by the world's most eminent critical care research group? Authors suggest that critical care has improved since the 1990s when Kress et al conducted their seminal trial: nurses and physicians are better-trained in the proper use of light sedation, and institutions have become less likely to "snow" patients wholesale. Sedation interruptions may not provide any incremental benefit over a steady, less-is-more approach to sedation of critically ill mechanically ventilated patients.
This trial could be considered the new standard -- displacing Kress et al's -- for at least two reasons. One, it's larger and multicenter, giving its findings more face validity. Second, it was pragmatic or "real-world" -- the actual care teams made the decisions and changes regarding sedation, whereas in Kress et al, unblinded research staff at a single institution (University of Chicago) tightly managed every daily sedation interruption. While it's certainly still possible that having a dedicated "sedationist" at the bedside would improve outcomes, it's more likely that improved training and a general shift in ICU culture toward less sedation use, combined with protocolized sedation, have improved the standard of care to the point that adding sedation interruptions doesn't help. And that sea change in critical care practice may be Kress et al's greatest contribution of all.
Sangeeta Mehta, Lisa Burry, Paul Hébert, et al. Daily Sedation Interruption in Mechanically Ventilated Critically Ill Patients Cared for With a Sedation Protocol. A Randomized Controlled Trial. JAMA 2012; ePub online October 17, 2012.