Do trauma patients on ventilators in the emergency department need multiple blood gas analysis to optimize treatment?

Introduction

The importance of adequate ventilatory support after severe trauma is highly stressed. However, this may lead to a tendency to hyperventilate trauma patients [1] put on a ventilator in the emergency department. The aim of this study was to investigate whether trauma patients on ventilator in the emergency department are hyperventilated.

Methods

A prospective collection of data for trauma patients put on a ventilator in the emergency department. The questionnaire included demographic information, indication for ventilation, analysis on initial and repeat arterial blood gases, and management changes. Patients were recruited over a period of 6 months from 1 November 2006 to 30 April 2007.

Results

Fifty-nine patients were identified, 54 (91.5%) were male and five (8.5%) were female. Age ranged from 4 to 60 years. The indication for ventilator treatment was isolated head injury in 28 (47.5%) patients, polytrauma in 13 (22%) patients, polytrauma with severe head injury in nine (15.3%) patients and isolated airway and ventilation indication in the remaining nine (15.3%) patients. Thirty-seven patients had a Glasgow coma scale (GCS) of 3 to 8, 13 had GCS of 9 to 12, and nine patients had GCS of 13 to 15. The first arterial blood gas was done within 10 minutes of ventilator treatment in 48 (81%) of the cases, whereas the second was done within 90 minutes in 41 (69.5%) of the cases. In 23 (39%) patients, pCO₂ was less than 30 mmHg on the first gas, and in 19 (32%) patients on the second gas. Oxygenation was adequate with levels above 200 mmHg in 40 (68%) of initial and in 47 (80%) of second gases. The most common ventilatory manipulation was a reduction in minute volume after the first gas in 14 (24%). Reduction of inspiratory oxygen was the most common change after the second gas in 28 (47%). The number of cases that should have had ventilatory adjustment was reduced from 12 (20%) after the first arterial blood gas to one (1.7%) after the second.

Conclusion

Although there was a tendency to hyperventilate patients on ventilators in the emergency department in our institution, satisfactory ventilation was achieved almost uniformly after the second blood gas analysis.