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reductions in the durations of mechanical ventilation, ICU stay, mortality, and the incidence of nosocomial pneumonia with postextubation support provided by NPPV. Appropriate patient selection and the feasibility of the widespread application of these findings remains to be determined. Recommendation 7. Anesthesia/sedation strategies and ventilator management aimed at early extubation should be used in postsurgical patients. Rationale and Evidence (Grade A) The postsurgical patient poses unique problems for ventilator discontinuation. In these patients, depressed respiratory drive and pain issues are the major reasons for ventilator dependence. Optimal sedation, pain management, and ventilator strategies offer opportunities to shorten the duration of mechanical ventilation. The McMaster AHCPR report4 identified 5 randomized controlled trials in postcardiac surgery patients161–165 that demonstrated that a lower anesthetic/sedation regimen permitted earlier extubation. The pooled results showed a mean effect of 7 hours. Similar effects were found using these approaches in other postsurgical populations.166–170 Ventilator modes that guarantee a certain breath rate and minute ventilation (assist control modes, IMV, and MMV) are important in patients with unreliable respiratory drives. However, frequent assessments and support reductions are necessary since recovery in these patients usually occurs over only a few hours. Aggressive support reduction strategies have been shown to lead to earlier discontinuations of ventilation.166,169 Conceptually, the immediate postoperative patient might be ideally suited for simple automatic feedback modes that provide a backup form of support (eg, MMV or ASV).120,156,158 Data showing improved outcomes or lower costs with these automated approaches, however, are lacking. Recommendation 8. Weaning/discontinuation protocols designed for nonphysician health care professionals (HCPs) should be developed and implemented by ICUs. Protocols aimed at optimizing sedation should also be developed and implemented. Rationale and Evidence (Grade A) There is clear evidence that nonphysician HCPs (eg, respiratory therapists and nurses) can execute protocols that enhance clinical outcomes and reduce costs for critically ill patients.171 In recent years, 3 randomized controlled trials incorporating 1,042 patients also have demonstrated that outcomes for mechanically ventilated patients who were managed using HCP-driven protocols were improved over those of control patients managed with standard care. Specifically, Ely et al108 published the results of a 2-step protocol driven by HCPs using a daily screening procedure followed by an SBT in those who met screening criteria. The discontinuation of mechanical ventilation was then recommended for patients tolerating the SBT. Although the 151 patients managed with the protocol had a higher severity of illness than the 149 control subjects, they were removed from the ventilator 1.5 days earlier (with 2 days less weaning), had 50% fewer complications related to the ventilator, and had mean ICU costs of care that were lower by $5,000 per patient. In a slightly larger trial with a more diverse patient population, Kollef et al119 used 3 different nonphysician-HCP-driven protocols and showed that the mean duration of mechanical EVIDENCE-BASED GUIDELINES FOR WEANING AND DISCONTINUING VENTILATORY SUPPORT RESPIRATORY CARE • JANUARY 2002 VOL 47 NO 1 79 ventilation could be reduced by 30 hours. Finally, Marelich et al172 showed that the duration of mechanical ventilatory support could be reduced almost 50% using nurse-driven and therapist-driven protocols (p 0.0001). The reproducibility of benefit for using various protocols in different ICUs and institutions suggests that it is the use of a standardized approach to management rather than any specific modality of ventilator support that improves outcomes. Indeed, when other key features in the management of mechanically ventilated patients, such as sedation and analgesia, also are subjected to protocols, further reductions in the time spent
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