Impact of a nurses' protocol-directed weaning procedure on outcomes in patients undergoing mechanical ventilation for longer than 48 hours: a prospective cohort study with a matched historical control group

Abstract

Introduction: The aim of the study was to determine whether the use of a nurses' protocol-directed weaning procedure, based on the French intensive care society (SRLF) consensus recommendations, was associated with reductions in the duration of mechanical ventilation and intensive care unit (ICU) length of stay in patients requiring more than 48 hours of mechanical ventilation.

Methods: This prospective study was conducted in a university hospital ICU from January 2002 through to February 2003. A total of 104 patients who had been ventilated for more than 48 hours and were weaned from mechanical ventilation using a nurses' protocol-directed procedure (cases) were compared with a 1:1 matched historical control group who underwent conventional physician-directed weaning (between 1999 and 2001). Duration of ventilation and length of ICU stay, rate of unsuccessful extubation and rate of ventilator-associated pneumonia were compared between cases and controls.

Results: The duration of mechanical ventilation (16.6 +/- 13 days versus 22.5 +/- 21 days; P = 0.02) and ICU length of stay (21.6 +/- 14.3 days versus 27.6 +/- 21.7 days; P = 0.02) were lower among patients who underwent the nurses' protocol-directed weaning than among control individuals. Ventilator-associated pneumonia, ventilator discontinuation failure rates and ICU mortality were similar between the two groups.

Discussion: Application of the nurses' protocol-directed weaning procedure described here is safe and promotes significant outcome benefits in patients who require more than 48 hours of mechanical ventilation.

Figure 1

Mechanical ventilation weaning protocol. Daily nurse screening identified patients eligible for weaning. A spontaneous breathing trial was considered to be successful when the patient could breathe spontaneously for 90 min without clinical intolerance. For such patients, physicians were then asked to approve discontinuation of mechanical ventilation. If the spontaneous breathing trial was not tolerated, then the patient was returned to their prior ventilator settings and screened the day after. FiO₂, fractional inspired oxygen; PEEP, positive end-expiratory pressure; SpO₂, pulse oximetry.

Figure 2

Case selection. ICU, intensive care unit; NIV, noninvasive ventilation.

Figure 3

Kaplan–Meier curves of the risk for remaining mechanically ventilated in protocol-directed (cases) versus physician-directed weaning groups (controls). The protocol-directed weaning procedure allowed reduction in the overall duration of mechanical ventilation, whatever the patient's diagnosis. The overall mechanical ventilation duration was 16.6 ± 13 days in cases and 22.5 ± 21 days in controls (P = 0.02).