Prediction of long-term ventilatory support in trauma patients

Abstract

Mechanical ventilatory support requiring tracheal intubation may be necessary for variable lengths of time in injured patients. Criteria useful in predicting the need for prolonged tracheal intubation has not been clearly established in the trauma population. Early identification of patients requiring prolonged tracheal intubation and mechanical ventilatory support could lead to earlier tracheostomy and subsequent reductions in complications associated with prolonged endotracheal intubation. This study evaluated the ability of clinical measures of injury severity, mental status, oxygenation, and ventilation to predict the need for prolonged mechanical ventilatory support (> or = 14 days) early in the postinjury course of the adult trauma patient requiring endotracheal intubation and mechanical ventilatory support within the first 24 hours of injury. All adult trauma patients admitted to our Level I trauma center over a 4-year period between January 1990-December 1993 were evaluated. A total of 212 patients met study criteria that included intubation within the first 24 hours of injury, ventilatory support requirement > or = 72 hours, and a survival time of at least 14 days postinjury. Data pertaining to measures of injury severity (RTS, AIS, ISS), mental status (GCS), oxygenation [(A-a)O2], and ventilation (VE,EDC) were recorded for postinjury Day 1 and Day 5. There were 157 males and 55 females (age range of 16-91 years, mean 39.5 years). Mechanism of injury was blunt in 198 and penetrating in 14 patients. One hundred patients required prolonged mechanical ventilatory support. Data were analyzed by stepwise logistic regression analysis. Age and GCS values on Day 1 predicted the need for long term mechanical ventilatory support in a select group of patients, age 20 and GCS of 3 (P < 0.05). At Day 5, age, GCS, and (A-a)O2 gradient were predictive of the need for prolonged mechanical ventilatory support (P < 0.05). On Day 5, GCS of 3 predicted the need for long-term mechanic al ventilatory support regardless of age or (A-a)O2 gradient. GCS < or = 5 and (A-a)O2 > or = 150 predicted prolonged mechanical ventilatory support in young patients (age 20). At ages of 40 to 60, GCS < or = 7 and (A-a)O2 > or = 150 indicated the need for long term mechanical ventilatory support. In older patients (age > or = 80), GCS < or = 7 and (A-a)O2 gradient > or = 100 were predictive of long-term mechanical ventilatory support. Appropriate use of these clinical indicators may assist in early identification of patients requiring prolonged mechanical ventilatory support, and subsequent conversion from endotracheal intubation to tracheostomy with anticipated reduction in complications.