The Frequency of Screening and SBT Technique Trial: The FAST Trial

The Frequency of Screening and SBT Technique Trial: The FAST Trial, A North American Weaning Collaboration

Background: The sickest patients who are admitted to an intensive care unit (ICU) often require assistance with their breathing. When patients start to get better, they gradually do more of the breathing and the machine does less-this is called weaning. Although ventilator use saves lives, the longer it is used, the more complications can occur. Clinicians aim to wean patients from ventilators in a timely and safe manner. In most ICUs, patients are screened (looked at) once per day to see if they are ready to undergo a weaning test (using a variety of techniques) to see if the breathing tube can be removed. Screening more than once per day may allow more weaning tests to be conducted. Knowing the best way to do a weaning test is important because some methods may better determine who can have the breathing tube removed safely. At present, we don't know the best way to help our sickest patients to wean from ventilators.

Patients: Adults in North American ICUs who are on ventilators for at least 24 hours and who can take breaths on their own.

Interventions: Patients in our study will receive one type of screening and one type of weaning test at random. In the 'once daily' screening groups, clinicians will screen patients each morning. In the 'two or more times daily screening' groups, patients will be screened in the morning, afternoon, and whenever else clinicians wish to screen. When screening criteria are met, patients will undergo one of two weaning tests with low ventilator support or no support.

Outcomes: The main outcome of this study will be the time for patients to be successfully removed from the ventilator.

Relevance: For patients, this study will clarify the best way to remove them from ventilators in a timely and safe manner. For clinicians and our health care systems, this study holds promise to improve how critically ill patients are weaned from breathing machines.

Goals

1. To identify the best strategy to wean patients from ventilators.
2. To fully engage patients and family members (PFM) in our trial.

Rationale: Nearly 40% of the time on invasive ventilation is spent weaning. In minimizing patients' exposure to invasive ventilation, clinicians are challenged by a trade-off between the complications associated with protracted ventilation and the risks [ventilator-associated pneumonia (VAP), mortality] of premature, failed attempts at extubation. Although randomized trials have been conducted to evaluate different screening practices and spontaneous breathing trial (SBT) techniques, most trials were small, predated daily screening, and have limited generalizability to the North American (NA) context where weaning involves respiratory therapists (RTs) and physicians.

In a systematic review of 17 trials (n=2,434), we found that screening protocols, compared to usual care, were associated with a 26% reduction in total duration of ventilation, a 70% reduction in weaning time, and an 11% reduction in ICU stay. Only 1 trial (n=385) compared twice daily screening to usual care and found that patients screened twice daily spent significantly less time on ventilators. Once daily screening is poorly aligned with the continuous care ICU environment. In our international survey, Pressure Support (PS) with positive end-expiratory pressure (PEEP) and T-piece were the most commonly used SBT techniques. Concerns exist that PS and T-piece SBTs may over and underestimate, respectively, patients' ability to breathe after extubation. Only 1 trial (n=484) has compared T-piece and PS SBTs and found no difference in outcomes. This trial was conducted in Europe, predated daily screening, and was underpowered.

Design: The investigators will conduct a factorial design trial involving 760 patients in 20 NA ICUs.

Population: The investigators will enroll critically ill adults receiving invasive ventilation for > 24 hours who can initiate or trigger breaths on commonly used weaning modes.

Comparators: Patients will be randomized to undergo a screening frequency (once vs. at least twice daily) AND an SBT technique (T-piece vs. PS ± PEEP).

Outcomes: The primary outcome will be the time to successful extubation. Secondary outcomes will include general and ventilation-specific outcomes that are important to citizens. We expect that more frequent screening, regardless of SBT technique, will reduce time to successful extubation.

This trial will identify the best strategy to reduce the time patients spend on ventilators and in ICUs, clarify best weaning practices, enhance care delivery, and launch a new paradigm of engagement into our research.

Inclusion Criteria:

1. Receiving invasive mechanical ventilation for > or = 24 hours.
2. Capable of initiating spontaneous breaths or triggering the ventilator to give a breath on ventilator modes commonly used in the ICU.
3. Fractional concentration of inspired oxygen (FiO2) < or = 70%.
4. Positive End-Expiratory pressure (PEEP) < or = 12 cm H2O.

Exclusion Criteria:

1. Brain death or expected brain death.
2. Evidence of myocardial ischemia in the 24 hour period before enrollment. Except if current trend in troponin is downward AND it has been > or = 24 hours since last troponin peak or the patient has undergone a revascularization procedure and attending physician has no concerns regarding ongoing ischemia.
3. Received continuous invasive mechanical ventilation for > or = 2 weeks.
4. Tracheostomy in situ at the time of screening.
5. Receiving a sedative infusion(s) for seizures or alcohol withdrawal.
6. Require escalating doses of sedative agents.
7. Receiving neuromuscular blockers or who have known quadriplegia, paraplegia or 4 limb weakness or paralysis preventing active mobilization.
8. Moribund (e.g., at imminent risk for death) or who have limitations of treatment.
9. Profound neurologic deficits (e.g., post cardiac or respiratory arrest, large intracranial stroke or bleed) or Glasgow Coma Scale (GCS) < or = 6.
10. Use of ventilator modes that automate SBT conduct.
11. Currently enrolled in a confounding study that includes a weaning protocol.
12. Previous enrollment in this trial.
13. Previous SBT or are already on T-piece, or CPAP alone (without PS), or PS < or equal 8 cm H2O regardless of PEEP, or other 'SBT equivalent' settings immediately before randomization.
14. Previous extubation [planned, unplanned (e.g. self, accidental)] during the same ICU admission.