Prognosis of non cardiac medical patients receiving mechanical ventilation in a veterans hospital

Abstract

In order to determine prognostic factors in noncardiac medical patients treated by mechanical ventilation in a Veterans Administration hospital, 78 patient records were reviewed. Disease severity was scored by the Acute Physiology and Chronic Health Evaluation (APACHE) II system. Physicians' prior impressions of prognostic factors were compared with the actual results of this study. Most patients were middleaged men with respiratory diseases. Fifty-nine patients (76 percent) died in the hospital. Survivors of hospitalization and nonsurvivors had similar age, diagnoses, emergency intubations, duration of ventilation, and pH and oxygen tension after 24 hours of ventilation. However, only one of 31 patients with a serum albumin level of 2.5 g/dl or less at the initiation of mechanical ventilation survived (p <0.001). Of 24 patients requiring a fractional inspired oxygen concentration greater than 50 percent at 24 hours, none survived (p <0.005). At all APACHE II scores, the mortality rates documented in this study were higher than predicted. Physicians overestimated the impact of several variables, including age and presence of pneumonia, on mortality. At the San Francisco Veterans Administration Medical Center, a low serum albumin level may aid in the decision wether to begin mechanical ventilation, and a high fractional inspired oxygen concentration at 24 hours may aid in the decision regarding further aggressive care. These findings need to be validated in other patients before being applied. Conversely, certain older patients, and those undergoing emergency intubation or intubation for a prolonged time, may have as good a prognosis as patients without these factors.