1995 OPEN FORUM Abstracts
THE PROGNOSTIC IMPLICATIONS OF A FAILED WEANING ATTEMPT.
Jennifer E. Anderson. RRT, N. Lennard Specht, MD, Schools of Allied Health Professions and Medicine, Loma Linda University, and Jerry L. Pettis Memorial VA Medical Center, 11201 Benton Street, Loma Linda, CA 92354.
Several scoring systems have been developed to predict the outcome of patients requiring intensive care. Scores are typically based on physiological variables. Patients with respiratory failure requiring long term mechanical ventilation (MV) have a higher mortality than patients requiring MV for shorter periods of time. To evaluate the prognostic impact of the success or failure of the initial weaning attempt in patients requiring short term mechanical ventilation, we undertook a prospective trial. Patients who required mechanical ventilation for 5 days or less were entered into the study if they consented to the study and were candidates for resuscitation attempts in the event of a cardiac arrest. Pulmonary mechanics were measured prior to initiating weaning. A weaning trial was attempted if two of the following weaning parameters were met: peak inspiratory pressure<-20 cm H_2O, respiratory rateន/min, tidal volume > 5cc/kg (ideal body wt.[IBW]), vital capacity > 10 cc/ kg (IBW). Weaning trials were standardized and lasted 4 hours. Patients were randomized to receive either intermittent T-piece trials or progressive reductions in pressure support level. A weaning trial was considered a success if the patient did not require mechanical ventilation for 24 hours after completing the weaning trial. A total of 67 patients began weaning trials. The technique used to wean the patients did not affect the weaning success rate or mortality. Weaning parameters were similar in the groups of patients who survived compared to non-survivors. Forty (40) patients passed their first weaning trial while 27 failed their initial weaning attempt. Six of the 40 patients (15%) who passed their initial weaning trial died prior to discharge from our facility. Of patients who failed their initial weaning attempt 13 of the 27 patients (48%) died while still hospitalized (pɘ.01). The difference in survival was most profound in patients over the age of 65 years. We conclude that recently intubated patients with respiratory failure who succeed on their first weaning trial have a substantially better prognosis than those who fail their initial weaning trial.