What are spontaneous awakening trials (SAT) in mechanically ventilated patients?

What are Spontaneous Awakening Trials (SAT)?

Spontaneous awakening trials (SAT) are a sedation management strategy involving daily interruption of continuous sedative infusions until the patient becomes awake and can follow simple commands, allowing for reassessment of sedation needs and facilitating earlier liberation from mechanical ventilation. 1

Definition and Mechanism

A spontaneous awakening trial consists of:

• Daily interruption of continuous sedative infusions (propofol, midazolam, etc.) until the patient awakens to a level where they can respond to commands 1
• Target awakening level: Patient should be able to perform at least three of the following actions upon request: open eyes, maintain eye contact, squeeze hand, stick out tongue, and wiggle toes 1
• This degree of responsiveness goes beyond merely "sleepy but arousable" and is essential for pain assessment through patient self-report, evaluating readiness to wean, performing delirium assessments, and implementing early mobility 1

Clinical Benefits and Outcomes

The landmark 2008 Awakening and Breathing Controlled (ABC) trial demonstrated that pairing spontaneous awakening trials with spontaneous breathing trials (SBTs) produces superior outcomes compared to standard sedation practices: 2

• Increased ventilator-free days: 14.7 days vs 11.6 days (mean difference 3.1 days, 95% CI 0.7-5.6; p=0.02) 2
• Shorter ICU length of stay: median 9.1 days vs 12.9 days (p=0.01) 2
• Shorter hospital length of stay: median 14.9 days vs 19.2 days (p=0.04) 2
• Reduced 1-year mortality: HR 0.68 (95% CI 0.50-0.92; p=0.01), with a number needed to treat of 7.4 2

Guideline Recommendations

The Society of Critical Care Medicine recommends that either daily sedation interruption or a light target level of sedation be routinely used in mechanically ventilated adult ICU patients (Grade 1B recommendation). 1

The Surviving Sepsis Campaign guidelines specifically note that: 1

• Daily interruption of continuous sedative infusions decreases duration of mechanical ventilation and ICU length of stay 1
• The combination of paired spontaneous awakening trials with spontaneous breathing trials is particularly effective, reducing duration of mechanical ventilation, ICU and hospital stay, and 1-year mortality 1

Implementation Approach

The "ABCDE" bundle represents an integrated approach to mechanically ventilated patients that incorporates spontaneous awakening trials: 3

• Awakening (spontaneous awakening trials)
• Breathing (spontaneous breathing trials)
• Choice of sedation (preferring α-2 agonists)
• Delirium monitoring
• Early mobility

This coordinated approach, termed "awake and breathing coordination," shortens duration of mechanical ventilation, ICU and hospital length of stay, and improves survival. 3

Safety Considerations

Self-extubation rates are higher with SAT protocols (16 patients vs 6 patients; 6.0% difference, 95% CI 0.6%-11.8%; p=0.03), but reintubation rates after self-extubation remain similar to standard care (1.2% difference, 95% CI -5.2% to 2.5%; p=0.47). 2

Myocardial ischemia concerns: A randomized prospective study demonstrated that although myocardial ischemia is common in critically ill ventilated patients, daily sedative interruption is not associated with increased occurrence of myocardial ischemia. 1

Special Populations Requiring Caution

Patients receiving neuromuscular blocking agents (NMBAs) must be individually assessed regarding discontinuation of sedative drugs because the neuromuscular blockade must first be reversed before conducting a spontaneous awakening trial. 1

Alternative Strategies

More recent evidence suggests that protocolized sedation targeting light sedation levels may be equally effective without requiring daily interruption: 1

• A 2012 multicenter trial (Mehta et al) found no difference in duration of mechanical ventilation or ICU length of stay between protocolized sedation alone versus protocolized sedation plus daily interruption 1
• Daily interruption was associated with higher daily opioid and benzodiazepine doses and increased nurse workload 1

The 2020 NONSEDA trial comparing no sedation to light sedation showed no mortality benefit (42.4% vs 37.0%, difference 5.4 percentage points; 95% CI -2.2 to 12.2; p=0.65), suggesting that the specific approach matters less than avoiding deep sedation. 1

Implementation Barriers

Despite proven benefits, only 48.6% of ICUs report regular SAT use (defined as >75% of mechanically ventilated patients undergoing SATs daily). 4

Key factors associated with successful implementation include: 4

• Addressing sedation goals routinely in rounds (OR 2.85,95% CI 1.55-5.23)
• Incorporating SATs into unit culture (OR 3.36,95% CI 1.75-6.43)
• Overcoming perception that SATs are "hard work" (OR 0.53,95% CI 0.30-0.96)

Common concerns that impede adoption include staff fears about adverse effects, perception of increased workload, and concerns about patient agitation and delirium. 4