Spontaneous Awakening and
Breathing Trials
Brad 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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Spontaneous Awakening and
Breathing Trials : VAP Prevention
Guidelines
• 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 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 safety
screenAwakening 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 safety
screen
• 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 successSBT
• 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.
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