ArticlesEfficacy and safety of a paired sedation and ventilator weaning protocol for mechanically ventilated patients in intensive care (Awakening and Breathing Controlled trial): a randomised controlled trial
Introduction
A third of patients in intensive care worldwide are mechanically ventilated.1 Although instituted to save lives, mechanical ventilation is nearly universally accompanied by the administration of large doses of sedatives;2 together these interventions are associated with significant morbidity.3, 4, 5, 6 Efforts to reduce the duration of mechanical ventilation in intensive-care populations via ventilator weaning protocols and sedation protocols can improve clinical outcomes.7, 8, 9 Unfortunately, only a few patients are managed with these strategies since there is ongoing disagreement among health-care professionals with regard to benefits and risks and because weaning protocols and sedation protocols are viewed as separate concerns—often handled in a cumbersome fashion by different members of the patient-care team (eg, sedation by nurses and ventilator weaning by respiratory therapists and physicians). Since the process of discontinuing ventilatory support is affected by heavy use of sedatives, there is an unmet need to combine approaches to sedation and ventilator weaning and to optimise their management.
Numerous randomised trials support the use of ventilator weaning protocols that include daily spontaneous breathing trials (SBTs) as their centrepiece; such protocols are standard of care, having reduced the duration of mechanical ventilation in diverse populations of patients with acute respiratory failure.7, 10, 11, 12, 13, 14 Recent clinical trials, seeking to identify ways to manage sedation that might also facilitate earlier extubation, have shown that both intermittent use of sedatives and spontaneous awakening trials (SATs)—ie, daily interruption of sedatives—can reduce the duration of mechanical ventilation without compromising patient comfort or safety.8, 9, 15 The paucity of additional evidence supporting the routine use of SATs, however, as well as anecdotal concerns regarding patient safety and agitation, have led to limited use of this sedation strategy. Whereas some intensive-care practitioners report only lightly sedating patients during most of their time on the ventilator, less than half of practitioners worldwide have implemented daily interruption of sedatives—eg, 34% in Germany,16 40% in Canada,17 and 40% in the USA.18, 19 Also, proponents of patient-targeted sedation strategies argue that titration of sedatives according to patients' needs produces outcomes equivalent to those resulting from a protocol that promotes daily SATs.20, 21
To test our hypothesis that routine SATs improve patient outcomes when combined with routine SBTs, we undertook the Awakening and Breathing Controlled (ABC) trial, a multicentre, randomised controlled trial in which we assessed the efficacy and safety of a protocol of daily SATs paired with SBTs versus a standard SBT protocol in patients receiving patient-targeted sedation as part of usual care.
Section snippets
Patients
We recruited participants at four large medical centres: Saint Thomas Hospital (Nashville, TN, USA), University of Chicago Hospitals (Chicago, IL, USA), Hospital of the University of Pennsylvania (Philadelphia, PA, USA), and Penn Presbyterian Medical Center (Philadelphia). Vanderbilt Coordinating Center (Nashville, TN, USA) supervised the trial; a Vanderbilt investigator was available 24 h a day to answer questions and respond to reports of adverse events.
Study personnel screened all patients
Results
1658 patients were considered eligible for enrolment between October, 2003, and March, 2006. We enrolled and randomised 336 of these individuals (figure 2). 168 patients were randomly assigned to each group. Seven (4%) patients in the control group discontinued the protocol: surrogates withdrew three patients from the study, and four patients were transferred to another service not participating in the trial. No patient in the intervention group discontinued the protocol; a surrogate withdrew
Discussion
Our results show that a paired sedation and ventilator weaning protocol consisting of daily SATs plus SBTs resulted in patients spending more time off mechanical ventilation, less time in coma, and less time in intensive care and the hospital, and the protocol improved 1-year survival compared with usual care. This wake up and breathe strategy was effective and was associated with few adverse events in a diverse population in intensive care in both community and university hospitals.
Respiratory
References (41)
- et al.
Ventilator-associated lung injury
Lancet
(2003) - et al.
The use of continuous i.v. sedation is associated with prolongation of mechanical ventilation
Chest
(1998) - et al.
Evidence-based guidelines for weaning and discontinuing ventilatory support: a collective task force facilitated by the American College of Chest Physicians; the American Association for Respiratory Care; and the American College of Critical Care Medicine
Chest
(2001) - et al.
Protocol weaning of mechanical ventilation in medical and surgical patients by respiratory care practitioners and nurses: effect on weaning time and incidence of ventilator-associated pneumonia
Chest
(2000) - et al.
PS power and sample size program available for free on the Internet
Controlled Clin Trials
(1997) - et al.
Characteristics and outcomes in adult patients receiving mechanical ventilation: a 28-day international study
JAMA
(2002) - et al.
Current practices in sedation and analgesia for mechanically ventilated critically ill patients: a prospective multicenter patient-based study
Anesthesiology
(2007) - et al.
Incidence of and risk factors for ventilator-associated pneumonia in critically ill patients
Ann Intern Med
(1998) - et al.
Lorazepam is an independent risk factor for transitioning to delirium in intensive care unit patients
Anesthesiology
(2006) - et al.
Effect on the duration of mechanical ventilation of identifying patients capable of breathing spontaneously
N Engl J Med
(1996)