The Science Journal of the American Association for Respiratory Care

2011 OPEN FORUM Abstracts

CONTRIBUTION OF VENTILATORY MODE TO SUCCESSFUL LIBERATION FROM MECHANICAL VENTILATION IN PATIENTS WITH EXACERBATION OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE.

Brianna J. Schimelpfenig1, Richard Hinds1, Wei-Shan C. Teo2, Mohamed H. Said2, Gemechis Daba2, Steven Holets1, Peter C. Gay3; 1Department of Anesthesiology, Mayo Clinic, Rochester, MN; 2Mayo School of Health Sciences, Rochester, MN; 3Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN

Background: Studies have suggested that assist-control mechanical ventilation may reduce respiratory muscle fatigue in patients with respiratory failure. Other studies have shown that assist-control ventilation may quickly lead to disuse atrophy of the diaphram, potentially complicating liberation from mechanical ventilation, supporting the use of pressure support ventilation around the time of extubation. No consensus has been reached as to which ventilatory strategy is best. Methods: To determine if there was a difference in the amount of time in pressure support ventilation between patients with successful and unsuccessful extubation, we carried out a single-center retrospective chart review of patients admitted an academic medical center from January 1st, 2010 to December 31st, 2010. Results: All patients who were admitted to the hospital with COPD and who required mechanical ventilation (n=192) were reviewed. We excluded patients that were not suspected of having an active COPD exacerbation, who were mechanically ventilated and managed at an outside ICU before transferring to our facility, were ventilated less than 12 hours, or had neuromuscular disease or other disease process, such as septic shock, that may prolong mechanical ventilation. Of the remaining patients (n= 31) we further excluded patients that underwent tracheostomy (n=3) and excluded from analysis, those that were DNR / DNI at the time of extubation (n=6). Of the remaining patients (n=22), 54.5% (n=12) of patients failed extubation. APACHE III scores in the successful extubation group (78.9 + 25.7) were similar to those in the unsuccessful group (80.1 + 25.2), as were Glascow Comma Scores (13.4 + 2.4) and (12.0 + 2.0) respectively. No significant difference was observed between successful and unsuccessful extubations in relation to the amount of time in pressure support ventilation in the 24 hours preceding extubation (P = .32, Wilcoxon rank sum test). Conclusions: We were unable to detect a significant difference in the amount of hours of pressure support ventilation preceding extubation between patients that had a successful extubation and those who did not. Our study shows that patients admitted for COPD exacerbation with no other major underlying conditions have a high rate of failed extubation. Further studies are needed to determine potential contributions of ventilatory mode on failed extubations in patients with COPD exacerbations.
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