Study objectives: To update our database, reporting changes in the results of weaning attempts and profile of patients transferred to us after prolonged mechanical ventilation (PMV) in the ICU.
Design: Retrospective record review, with prospective recording of physiologic measurements on admission from mid-1994.
Setting: Regional weaning center (RWC).
Patients: We studied 1,123 consecutive ventilator-dependent patients transferred for attempted weaning over an 8-year period.
Measurements and results: Median (range) time of mechanical ventilation prior to transfer to the RWC declined from 37 (1 to 249) days in 1988 to 29 (1 to 120) days in 1996 (p<0.05). Acute physiology score of acute physiology and chronic health evaluation (APACHE) III was 32 (6 to 123) on RWC admission, equaling reported scores soon after ICU admission. Comparing other data on admission from 1988 to 1996, mean (±SD) serum albumin level declined from 2.92±0.58 to 2.43±0.50 g/dL, and alveolar-arterial oxygen pressure difference widened from 106±50 to 139±99 mm Hg. Prevalence of stage II or worse pressure ulceration on admission increased from 34% in 1988 to 46% in 1995. Despite these trends, there has been no significant change in patient outcome (55.9% weaned, 15.6% failed to wean, 28.8% died) or in median time to wean (29 [1 to 226] days). Overall survival at 1 year after discharge for the 8-year period is 37.9%, improving from 29% in 1988-1991 to 45% since 1992; survival in weaned patients discharged to home has improved from 45 to 59% during the respective time periods.
Conclusions: Patients are being transferred from the ICU to our RWC for attempted weaning sooner in their course of PMV. Although more severely ill on arrival than in past years, mortality is unchanged, more than half of the patients continue to be successfully weaned, and survival after RWC discharge is improved.