PURPOSE: We have shown that patients who remain free from mechanical ventilation for more than 4 continuous weeks form a robust group of patients in terms of both survival and discharge home. This study was to determine in these patients when prolonged mechanical ventilation (PMV) was again required, i.e. when a relapse occurred after successful weaning.
METHODS: In 967 patients requiring PMV, 319 (33%) achieved freedom from ventilator support for more than 4 weeks between January 1st 2001 and December 31st 2006. They were followed thru discharges, readmissions or April 25th, 2008. Data was extracted from the medical record. The intervals in days from the end of successful weaning to return to PMV were determined and then grouped. Ten of the successfully weaned were excluded from this analysis because of missing information (n=309).
RESULTS: There were 115 instances of relapse to PMV in 95 (31%) of the 309 study patients, 214 patients had no relapse. Zero instances of relapse occurred in the first week after 4 weeks free from any ventilator support; 7 in the 2nd week; 15 between 2 and 4 weeks; 36 between 1 and 6 months; 19 between 6 and 12 months; 28 between 1 and 3 years; and 10 between 3 and 6 years. In 79 patients there was only one relapse. More than one relapse occurred in 16 patients. The shortest interval after 4 weeks freedom was 10 days; the longest 5 years and 4 months.
CONCLUSION: These findings confirm the robustness of PMV patients who achieved 4 weeks free from any ventilatory support in that 69% of patients (214 of 309) did not again require PMV. Furthermore 33% (38 of 115) of relapses occurred after one year or more free from ventilator support.
CLINICAL IMPLICATIONS: These findings may help provide long term prognoses for those patients liberated from all ventilator support after PMV. Further studies of the clinical characteristics of those who had and did not have late relapses are warranted.
DISCLOSURE: J Dermot Frengley, No Financial Disclosure Information; No Product/Research Disclosure Information