Effects of Reinstitution of Prolonged Mechanical Ventilation on the Outcomes of 370 Patients in a Long-Term Acute Care Hospital.

OBJECTIVE: To investigate the effects of the reinstitution of continuous mechanical ventilator support of >21 days in 370 prolonged mechanical ventilation (PMV) patients, all free from ventilator support for ≥5 days. METHODS: Four groups were formed based on the time and number of PMV reinstitutions and compared (group A: reinstitutions within 28 days, n = 51; group B: a single reinstitution after 28 days, n = 53; group C: multiple reinstitutions after 28 days, n = 52; and group D: no known reinstitutions, n = 214). RESULTS: Of the 370 patients, 156 (42%) required PMV reinstitutions. Most reinstitutions occurred within 7 months: 51 (33%) of the 156 patients within 28 days and 49 (31%) within the next 6 months. Group comparisons revealed a progression of outcomes from group A, the worst, to group D, the best, with groups B and C having intermediate but significantly different values. Decannulation was associated with an 88% decreased risk of PMV reinstitution and a 43% lower risk of death (all P < .001). CONCLUSION: Prolonged mechanical ventilation reinstitution rates were high, with most occurring within 7 months of freedom from MV. In general, the longer the period of ventilator freedom, the less the likelihood of a PMV reinstitution. The identification of 4 distinct PMV groups of patients by time and number of reinstitutions added useful prognostic information. Since PMV reinstitutions within 28 days lead to permanent MV support, >28 days of ventilator freedom provided an optimal cut point for assessing the likelihood of again requiring PMV.

Relationship of the Duration of Ventilator Support to Successful Weaning and Other Clinical Outcomes in 437 Prolonged Mechanical Ventilation Patients.

OBJECTIVE: To investigate the relationships between durations of ventilator support and weaning outcomes of prolonged mechanical ventilation (PMV) patients. METHODS: Cohort study of 957 PMV patients sequentially admitted to a long-term acute care hospital (LTACH). The study population was 437 PMV patients who underwent weaning, having achieved ≥4 hours of sustained spontaneous breathing. They were divided into tertiles of mechanical ventilation (MV) durations and compared for differences (tertile A: 21-58 days, n = 146; tertile B: 59-103 days, n = 147; and tertile C: ≥104 days, n = 144). RESULTS: Tertiles showed comparable weaning success rates and survival. As MV durations increased, LTACH postweaning days became progressively greater, whereas decannulations and discharge physical function diminished, and home discharges decreased while nursing facility discharges increased (all P < .001). Patients with lower physical function before critical illness or greater burdens of comorbidities were least likely to be weaned (all P < .001). Younger ages, lower comorbidity burdens, neurological diagnoses, higher admission prealbumin levels, and successful weaning, each independently reduced the risk of death (all P < .01). CONCLUSION: Durations of MV did not affect weaning success or survival, although deleterious effects were found in discharges, decannulations, LTACH postweaning days, and discharge physical function. Durations of MV alone should not guide transfer decisions for subsequent continuing care.

A comparison of seriously ill patients with or without AIDS requiring prolonged mechanical ventilation.

PURPOSE: The aim of this study was to compare differences in underlying diagnoses, weaning outcomes, discharge disposition, and survival in prolonged mechanical ventilator (PMV)-dependent patients with and without AIDS. METHODS: Ninety consecutive AIDS patients requiring PMV were retrospectively matched with 90 clinically similar non-AIDS patients to form matched cohorts to determine differences in their outcomes. RESULTS: AIDS patients had more acute diagnoses requiring PMV, whereas non-AIDS patients had more chronic diagnoses (P < .001). Weaning outcomes were alike with 31 (35%) AIDS and 37 (41%) non-AIDS patients successfully weaned. More AIDS patients went home, and fewer, to nursing facilities (P = .04). In each cohort, successfully weaned patients had significantly longer survival than their unweaned counterparts (all P < .001). Successful weaning reduced the risk of death in AIDS and non-AIDS patients (hazard ratios, 0.29 and 0.20; 95% confidence intervals, 0.17-0.50 and 0.11-0.36, respectively; all P < .001). CONCLUSIONS: AIDS had little effect on weaning success or survival. Successful weaning increased survival regardless of a diagnosis of AIDS. The AIDS patients had more home discharges and fewer to nursing facilities, which likely resulted from the AIDS patients having more acute illnesses leading to PMV than the non-AIDS patients.