Ventilator Series: Sedation Vacation
Written by Dr. Evan Robinson
Sedation Vacations in the Intensive Care Unit
Sorry, pure EM folk, this topic primarily applies to the unit. For most of us, the idea of a “daily sedation vacation” is probably a familiar and standard practice in the intensive care unit (ICU). Generally defined, a sedation vacation is when sedatives are discontinued for a period of time and the patient is allowed to become alert. This often coincides with a spontaneous breathing trial, but these can be mutually exclusive events. What is the data that guides this practice?
A landmark paper came out in NEJM back in 2000 that really drives our current way of practice. Kress et. al.¹ performed a single-center randomized controlled trial (RCT) with 128 adult ICU patients who were ventilated and sedated. There were two arms, a control group undergoing usual care and were sedated with propofol or midazolam (which agent was up to the discretion of the intensivist not directly involved in the study) plus morphine, and the intervention group had the same drugs administered but each day they were held until the patient woke up. The results were impressive: 2 fewer days on the ventilator, and 3.5 fewer days in the ICU! All without increased adverse outcomes such as self-extubation, tracheostomy, etc. Hospitals would save millions, patients were on the vent for less time, in theory leading to decrease PTSD, etc. But, could this study be replicated?
In 2008, Girard et. al.² published the “Awake and Breathing Trial”, or ABC Trial in The Lancet. ABC basically replicated the study protocol for Kress’s group, but this time it was a multi-center RCT, and they paired it with a spontaneous breathing trial (SBT), and enrolled 336 patients. Similar to Kress, they found patients in the intervention group spent 3 days less on the ventilator and 3 days less in the ICU. They did find a slightly higher incidence of self-extubation, but few of these required re-intubation.
Unfortunately, both of these studies suffer from similar flaws. In each, the intensivist providing sedation did so according to his/her own discretion and hospital protocols. The study methods did not define what sedation tool they were using (RASS vs Ramsay vs SAS), nor did they define the goal level of sedation. In 2012, Mehta and colleagues³ attempted to create a more rigorous study and published the “SLEAP Study” in JAMA.
After conducting a smaller pilot trial, they enrolled 430 ICU patients in 16 centers to conduct the RCT. Similar to the ABC Trial, there were two arms and the intervention arm included an SBT. The key difference in this large trial was strict protocolization of how sedation should be achieved. The Sedation Agitation Scale (SAS) was used, with a goal of 3-4 (sedated/calm and cooperative), and nursing staff had an algorithm at bedside to titrate sedation to achieve this score. In addition, it’s important to note that it was nursing staff adjusting sedation, not the researchers as in the Kress trial (Girard used nursing staff/respiratory therapists). Interestingly, in this trial, the median length until extubation was 7 days in both arms. Unfortunately, SLEAP did not measure duration of intubation, only ventilator free days, so the median cannot be compared. Kress did measure the median to be 4.9 vs 7.3.
It is unclear why the patients in this trial tended to be intubated for 2 days longer even in the intervention arm compared to Kress. Possibly these were sicker patients overall. SLEAP makes a strong argument that sedation vacations do not appear to improve patient outcomes. However, this result may be due to maintaining lighter levels and stricter control of sedation in general due to the protocols used. Akin to how the Rivers trial for sepsis has modified “usual care”, it’s possible the older studies have caused a paradigm shift towards less sedation in general, which is what really improves outcomes.
The take home point is to be vigilant about the level sedation we use in our patients, erring on the side of less is more. Choose a scale (RASS/SAS/Ramsay), stick with it, and create a protocol for nursing staff to follow. Wake your patients up if you so choose — it probably doesn’t cause harm and is possibly beneficial — but know this is time intensive for your nursing staff. More importantly, attempt to liberate your patients from the ventilator every day.
Kress et al. Daily interruption of sedative infusions in critically ill patients undergoing mechanical ventilation. N Engl J Med 2000;342:1471-7
Girard et al. Efficacy and safety of a paired sedation and ventilator weaning protocol for mechanically ventilated patients in intensive care (Awakening and Breathing Controlled trial): a randomised controlled trial). Lancet 2008;371(9607):126-134
Mehta et al. Daily Sedation Interruption in Mechanically Ventilated Critically Ill Patients Cared for With a Sedation Protocol. A Randomized Controlled Trial (SLEAP study). JAMA 2012;308(19):1985-1992