Spontaneous Awakening and Breathing TrialsBrad Winters MD, PhD

March 14, 2013

Spontaneous Awakening and Breathing Trials (SAT &SBT)

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Spontaneous Awakening and Breathing Trials : VAP Prevention Guidelines

• Does not specifically address SAT and SBT, however supports weaning.

• CDC; MMWR Recomm Rep. 2004;53:1-36

• Recommends use of daily interruption or lightening of sedation to avoid constant heavy sedation and to facilitate and accelerate weaning.

• Does not specifically address SBT. • ATS/IDSA; AJRCCM 2005;171(4):388-416.

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• Guideline excluded studies that evaluated SAT and SBT.• Canadian VAP Prevention Guidelines; J Crit Care

2008;23(1):138-147.

• Recommends the use of combining a daily assessment of readiness wean and daily sedation interruption.

• SHEA; ICHE 2008;29:S31-S40.

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Spontaneous Awakening and Breathing Trials : VAP Prevention Guidelines

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Spontaneous Awakening Trials

Population• Medical ICU patients on mechanical ventilation

Intervention (RCT)• Control group: no interruption (N= 68) • Rx group: daily interruption (N= 60) sedation held

daily until the patients were awake and could follow instructions or uncomfortable or agitated.

• All patients received an infusion of morphine for analgesia.

Kress et al. NEJM 2000; 342:1471-77

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Spontaneous Awakening Trials

Outcomes• 2.4 day reduction duration mechanical ventilation

– 33% relative risk reduction• 3.5 day reduction ICU length of stay

– 35% relative risk reduction • Hospital length of stay unchanged: control group 16.9

days (8.5-26.6 days) compared to rx group 13.3 days (7.3-20.0 days).

Kress et al. NEJM 2000; 342:1471-77

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Spontaneous Breathing Trials

Population• Adult medical and coronary ICU patients on

mechanical ventilation (n=300)

Intervention (RCT)• Control group: daily screening (RSBI*) (n=151)• Experimental group: daily screening (RSBI) followed

by 2-hour SBT (n=149) if they passed the screening test

• Physicians were notified when their patients successfully completed the trial of spontaneous breathing.

*RSBI: rapid shallow breathing index Ely et al. NEJM 1996; 335:1864-69.

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Spontaneous Breathing Trial (SBT)

• Patient passes SBT safety screen• Ventilatory support is removed and the patient is

allowed to breathe through either a T-tube circuit or a ventilatory circuit using “flow triggering” (rather than triggering by pressure) with a continuous positive airway pressure of 5 cm of water.

• No changes are required in the fraction of inspired oxygen or the level of positive end-expiratory pressure.

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Spontaneous Breathing Trials

Outcomes• 1.5 day reduction duration mechanical ventilation

– 25% relative risk reduction

• 1.0 day reduction ICU length of stay– Not statistically significant

• Reductions total ICU costs

• Reductions in complications including reintubation

Ely et al. NEJM 1996; 335:1864-69.

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Treatment protocol

Girard et al. Lancet 2008; 371: 126–34

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ABC Trial: Awakening and Breathing Controlled trial

Population• 336 ICU patients on mechanical ventilation• Four tertiary-care hospitals

Intervention (RCT)• Control group: sedation per usual plus daily SBT

(n=168)• Rx group: daily SAT followed by SBT (n=168) All

patients received an infusion of morphine for analgesia.

Girard et al. Lancet 2008; 371: 126–34

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ABC Trial: Awakening and Breathing Controlled trial

• 3.1 increased days without mechanical ventilation– 21% relative risk increase

• 3.8 day reduction ICU length of stay– 29% relative risk reduction

• 4.3 day reduction hospital length of stay– 22% relative risk reduction

• Number needed to treat (NNT) = 7.4 for one life saved

Girard et al. Lancet 2008; 371: 126–34

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Practical SAT

• The SAT consists of two parts,– a safety screen and– the trial.

• The safety screen attempts to assure the trials will not be used when contraindicated. Patients pass the screen unless:

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The Safety Screen

• Sedation for active seizures or alcohol withdrawal

• Already receiving escalating doses of sedative for agitation

• Receiving neuromuscular blockers• Active myocardial ischemia in prior 24

hours• Evidence of increased ICP

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If patient passes the safetyscreenAwakening Trial

• All sedatives and analgesics used for sedation are stopped. Analgesics used for pain are continued.

• A patient passes the SAT if awake and can do 3 of 4 simple tasks on request: open eyes, look at caregiver, squeeze hand or stick out their tongue.

• OR

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If patient passes the safetyscreen

• can go ≥ 4 hrs w/o– sustained anxiety– Agitation or pain– RR of 35 for >= 5 minutes– SpO2 < 88% for >=5 minutes

– an acute cardiac dysrhythmia– ≥ 2 signs of respiratory distress

• Tachycardia, bradycardia, use of accessory muscles, abdominal paradox, diaphoresis, obvious distress

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SAT Failure

• If a patient fails the SAT, sedatives are restarted at one half the prior dosage and titrated up as needed.

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SAT Success?

• Maintain adequate oxygenation (SpO2 >=88% on an F1O2 of ≤50% and a PEEP ≤8 cm H2O)

• any spontaneous inspiratory effort in a 5-min period

• no agitation• no significant use of pressors or

inotropes• no evidence of increased ICP

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SAT successSBT

• Patient breathes through either a T-tube circuit of a ventilatory circuit with CPAP of 5cm H2O or pressure support ventilation of less than 7cm H2O.

• Typically FIO2 is ≤50% and PEEP≤8

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SBT success?

• Patients pass the trial if they don’t develop any of the same criteria as for the SAT for 120m

• If they pass, the prescriber is notified for extubation order.