The Vitals: Spontaneous Awakening Trials 101

Spontaneous awakening trials (SATs) arose when clinicians and researchers started to wonder if their patients were staying on the vent longer than necessary and thereby risking complications. Long continuous infusions led to prolonged sedatives and longer time to assess neurologic status for extubation. Instead of depending on clinical gestalt to determine when a patient is ready to be weaned off the ventilator, what if we just woke up the patient and let them guide us?

The Research

A number of studies have been completed since the mid-1990s that explored ventilator weaning via spontaneous awakening trials. While a review is beyond the scope of this post, it is worth taking a look at some of the highlights of the research.

• In one of the original studies assessing the daily interruption of sedatives, Kress et al. conducted a single center, randomized, controlled trial that compared SATs in an intervention group versus the cessation of sedatives based on clinicians judgement in a control group. They found that, compared with the control group, the intervention group spent a median duration of 2.4 days less on mechanical ventilation and 3.5 fewer days in the ICU.
• In the Awakening and Breathing Control (ABC) trial (Girard, Kress, et al.), a multicenter study, researchers paired SATs with spontaneous breathing trials (SBTs). The intervention group underwent SATs daily and then SBTs if tolerated, while the control group relied on an individualized approach determined by the intensivist. 150 patients in the intervention group underwent 895 SATs and passed 837 (94%). In the control group, only 31% of patients (52/168) had their sedatives held before an SBT, suggesting that many of our patients might be ready for SBTs earlier than expected. Overall, those in the intervention group spent more days breathing without assistance, were more alert on the day they passed their SBT screen, required less overall benzodiazepines, and had a four day earlier discharge from the ICU and the hospital.
• In a study by Balas et al, researchers assessed awakening and breathing coordination (daily SATs and SBTs if eligible), delirium management (via CAM-ICU and RASS scores), and early exercise (PT/OT consults) (the ABCDEF bundle) in a single-center study of 5 ICUs. By comparing patients treated in the 8 months prior to the implementation of an ABCDE protocol to the 7 months afterwards, they found that the latter group was more likely to undergo an SAT and an SBT, have more days breathing without the ventilator, was less likely to become delirious, and more likely to be mobilized out of bed.
• One negative study of SATs was a randomized, controlled trial of 16 ICUs over a three year period, performed by Mehta et al. In the control group, researchers implemented a protocolized analgesia and sedation strategy based in opioids and benzodiazepines that used the Richmond Agitation Sedation Scale (RASS) or the Sedation-Agitation Scale (SAS) to determine how to titrate these drugs. In the intervention group, the patients underwent the protocolized strategy plus daily sedation interruptions. Their primary outcome found no difference in time spent on the ventilator in both groups (~7 days). However, this study suffered from some weaknesses including poor adherence to SATs and the absence of often used medications propofol, ketamine, and dexmedetomidine in their sedation strategy.
• The 2018 Clinical Practice Guidelines for Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU (PADIS) recommends light sedation over deep sedation in intubated, critically ill patients. Their review of the literature found no significant difference between SATs and nursing protocolized care. However, they note that most studies used benzodiazepines for sedation, which are no longer recommended. They also make the caveat that SATs often lead to an increased nursing workload.

Guidelines for Spontaneous Awakening Trials

Let’s say you want to try a spontaneous awakening trial. What are the recommended guidelines?

To further continue the alphabet one-upmanship, the Society of Critical Care Medicine established the ICU Liberation Bundle (ABCDEF, now including Family Engagement and Empowerment). Here they advise using the ABC trial’s “Wake Up and Breathe Protocol.” This recommendation is echoed by the Agency for Healthcare Research and Quality.

The SAT consists of two parts: a safety screen and the actual assessment.

1. First the ICU team must identify patients who are on full ventilator support and responding to verbal stimuli. These patients are eligible for an SAT.
2. However, patients are ineligible if they meet any of the following criteria:
   1. Receiving sedative infusions for alcohol withdrawal or seizures
   2. Requiring increasing doses of sedative for agitation
   3. Increased intracranial pressure
   4. Active myocardial ischemia in the past 24 hours
   5. Receiving paralytics (neuromuscular blockers)
3. If the patient passes the safety screen all sedatives and analgesics for sedation are ceased. However, medications for pain are continued as required.
4. Patients must be able to do one of the following:
   1. Perform three out of four of tasks: open their eyes, squeeze a hand, look at their caregiver, or stick out their tongue
   2. Go at least four hours without:
      1. Sustained or increasing anxiety, agitation, or pain
      2. Tachypnea (> 35 breaths per minute) for at least 5 minutes
      3. Demonstrating SpO2 < 88% for at least 5 minutes
      4. Have acute cardiac dysrhythmias
      5. Demonstrate signs of  respiratory distress (tachycardia, bradycardia, accessory muscle use, dyspnea, diaphoresis)
5. If the patient fails the SAT, the sedation is restarted at half the original dosage and then titrated for pain and sedation.
6. But if the patient passes the SAT, then the patient moves on to a spontaneous breathing trial!