Tight control of prehospital ventilation by capnography in major trauma victims

Background. Tracheal intubation combined with controlled ventilation of the lungs is an important part of the prehospital management of major trauma victims, but gauging the adequacy of ventilation remains a major problem. Methods. Ninety-seven major trauma victims who underwent tracheal intubation in the field and controlled ventilation of the lungs during prehospital treatment by a Helicopter Emergency Medical Service were assigned randomly to one of two groups: (1) monitor group (n=57) and (2) monitor-blind group (n=40), according to whether the anaesthetist could or could not see an attached capnograph screen. In the monitor-blind group ventilation was set by using a tidal-volume of 10 ml kg(-1) estimated body weight and an age-appropriate ventilatory frequency. In the monitor group, ventilation was adjusted to achieve target end-tidal carbon dioxide values determined by the 'physiological state' of the trauma victim. Arterial blood gases were measured upon hospital admission while maintaining the ventilation initiated in the field and the Pa-CO2 value obtained was used as the determinant of the adequacy of prehospital ventilation. Results. The incidence of 'normoventilation' was significantly higher (63.2 vs 20%; P<0.0001) and the incidence of 'hypoventilation' upon hospital admission was significantly lower (5.3 vs 37.5%; P<0.0001) in the monitor group; patients with severe head and chest trauma and haemodynamically unstable patients and those with a high injury severity score were significantly more likely to be 'normoventilated' upon hospital admission in the monitor group than in the monitor-blind group. Conclusions. The data support the routine use of prehospital capnographic monitoring using target end-tidal carbon dioxide values adapted to the physiological state of the patient in major trauma victims requiring tracheal intubation in the field.