Evidence-Based Medicine
Over 90 percent of critically ill patients require mechanical ventilation, and 40 percent of the time the patient is on mechanical ventilation is spent on weaning the patient from ventilation. Once the conditions that warranted the ventilator stabilize and begin to resolve, doctors try to remove the ventilator as quickly as possible to decrease the likelihood of ventilation-related complications such as pneumonia or airway trauma. On the other hand, premature discontinuation of mechanical ventilation carries its own set of problems, including fatigue, cardiac instability, difficulty in reestablishing artificial airways, and compromised gas exchange.
To address the many issues involved in management of mechanically ventilated patients, the Agency for Healthcare Research and Quality provided support to the McMaster University Evidence-based Practice Center (contract 290-97-0017) for a comprehensive review of the scientific evidence on ventilator weaning/discontinuation. Led by Deborah Cook, M.D., this exhaustive review of several thousand articles resulted in an evidence report that was published by AHRQ in 1999 (see Editor's Note below). The American College of Chest Physicians, the American College of Critical Care Medicine, and the American Association for Respiratory Care formed a task force that used the McMaster EPC report to produce evidence-based clinical practice guidelines for managing the ventilator-dependent patient during the discontinuation process.
The guidelines address five issues:
- The pathophysiology of ventilator dependence.
- The criteria for identifying patients who are capable of ventilator discontinuation.
- Ventilator management strategies to maximize the discontinuation potential (for example, spontaneous breathing trials that are slow-paced and gradually lengthened before consideration of permanent ventilator discontinuation).
- The role of tracheotomy (often used when the patient requires prolonged ventilator assistance).
- The role of long-term care facilities, for example, for chronically ventilated patients.
An article describing the guidelines and eight related articles were published in a supplement to the December 2001 issue of Chest 120(6).
These articles are cited here:
- Collective Task Force, "Evidence-based guidelines for weaning and discontinuing ventilatory support," December 2001 Chest 120(6) pp. 375S-395S.
- Cook, D., Meade, M., Guyatt, G., and others, "Trials of miscellaneous interventions to wean from mechanical ventilation," December 2001 Chest 120(6), pp. 438S-444S.
- Cook, D., Meade, M., and Perry, A., "Qualitative studies on the patient's experience of weaning from mechanical ventilation," December 2001 Chest 120(6), pp. 469S-473S.
- Ely, E.W., Meade, M., Haponik, E.F., and others, "Mechanical ventilator weaning protocols driven by nonphysician health care professionals," December 2001 Chest 120(6), pp. 454S-463S.
- Meade, M., Guyatt, G., Butler, R., and others, "Trials comparing early vs. late extubation following cardiovascular surgery," December 2001 Chest 120(6), pp. 445S-453S.
- Meade, M., Guyatt, G., Cook, D., and others, "Predicting success in weaning from mechanical ventilation," December 2001 Chest 120(6),
pp. 400S-424S.
- Meade, M, Guyatt, G, Cook, D., and others, "Trials of corticosteroids to prevent postextubation airway complications," December 2001 Chest 120(6), pp. 464S-468S.
- Meade, M., Guyatt, G., Griffith, L., and others, "Section II: Systematic reviews of the evidence base for ventilator weaning," December 2001 Chest 120(6), pp. 396S-399S.
- Meade, M., Guyatt, G., Sinuff, T., and others, "Trials comparing alternative weaning modes and discontinuation assessments," December 2001 Chest 120(6), pp. 425S-437S.
Editor's Note: Copies of the AHRQ evidence report (AHRQ Publication No. 01-E010) are available from the AHRQ Publications Clearinghouse. Copies of the summary (AHRQ Publication No. 00-E028) are available from the AHRQ Publications Clearinghouse and AHRQ InstantFAX.
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