DO AGE AND GENDER INFLUENCE OUTCOME FROM MECHANICAL VENTILATION

Objectives: To define the role of age and gender on outcome from mecha nical ventilation. Design: Prospective analysis of consecutive patient s. Setting: A military-referral medical center. Patients: A total of 2 40 consecutive patients requiring 246 episodes of mechanical ventilati on. Measurements: Demographic, clinical, and outcome data. Results: Un ivariate statistical techniques comparing 13 variables between survivo rs and nonsurvivors of an episode of mechanical ventilation indicated that the following eight variables were significantly different (p < 0 .05) between these two groups: age, length of intensive care unit stay , duration of MV, Acute Physiology and Chronic Health Evaluation (APAC HE) II score, Age Removed APACHE II score, Organ System Failure Index (OSFI), patient diagnostic category, and presence of malignancy. Patie nt sex demonstrated a trend towards significance (p = 0.051). These ni ne variables were entered into a stepwise logistic regression analysis to develop a model to predict outcome from mechanical ventilation. Th is model showed that only the OSFI (p < 0.001) and the APACHE II score (p = 0.0281) independently predict ed outcome from mechanical ventila tion. Similar analyses were performed to identify outcome predictors a fter segregating the patients according to age (less than 70 years and equal to or greater than 70 years) and according to sex. In the first of these subsequent analyses the OSFI was found to be the sole indepe ndent predictor of outcome for both older and younger subgroups. In th e second analysis the OSFI, length of hospital stay, and duration of m echanical ventilation predicted outcome for male patients while the OS FI alone independently predicted outcome for female patients. Fifty-tw o survivors of mechanical ventilation over the age of 70 years were ob served after hospital discharge (average follow-up time 2.75 +/- 1.36 months) to assess their need for institutional care after hospital dis charge. Five of these patients (9.6%) required long-term care in a nur sing home or rehabilitation hospital until their deaths (four patients ) or discharge to home (one patient). With a stepwise logistic regress ion analysis, only the intensive care unit length of stay was found to be a significant independent predictor for this outcome. Conclusions: These results suggest that the occurrence of derangements in organ fu nction as described by the OSFI best predicts outcome from mechanical ventilation. Age and sex do not significantly contribute to patient ou tcome independent of organ system dysfunction.