Inadequate ventilation of patients with severe brain injury: a possible drawback to prehospital advanced trauma care?

Objectives: To assess the appropriateness of arterial carbon dioxide tension control in a group of 92 patients with traumatic brain injury who, despite receiving advanced prehospital care, showed no improved outcome in comparison with a group homogeneous but for a lower level of prehospital care. Methods: A retrospective registration of the early in-hospital arterial carbon dioxide tension of the patients intubated and ventilated on scene. Patients were excluded if the arterial carbon dioxide tension did not reflect prehospital ventilation or its alteration might have been intentional or unavoidable. Results: Arterial carbon dioxide tension was normal (35-45 mmHg) in only six of the 16 suitable cases (37.5%), was elevated (>45 mmHg) in three cases (18.75%), low (25-35 mmHg) in five cases (31.25%), and extremely low (<25 mmHg) in two cases (12.5%). Conclusion: Potentially dangerous alterations in capnia occurred in the majority of patients analysed. The possible consequences and causes are discussed. Further studies are needed to assess the consequences of any deviation from ideal standards, and to set realistic standards of arterial carbon dioxide tension control during prehospital ventilation.