[Measurement of carbon monoxide in expired breath in prehospital management of carbon monoxide intoxication].

Introduction: Carbon monoxide detectors are currently used by the French prehospital medical teams. These detectors can also be used to measure expired breath carbon monoxide concentration. The interest of this measurement has never been studied.

Objective: To evaluate interest of expired breath carbon monoxide concentration measurement in the management of prehospital carbon monoxide intoxication.

Study Design: Patients with carbon monoxide poisoning were included during 1998.

Patients And Methods: Four levels of clinical severity: no symptom, minor, medium or severe intoxication were defined. Carbon monoxide concentration were measured in the expired breath (COHbe) at the place of the intoxication and in blood samples collected at the place of the intoxication (COHbs) and at the hospital (COHbh).

Results: 209 patients were included, 144 had no symptom (55%), the value of COHbe was 11.6 +/- 7.5% (mean +/- DS) and the value of COHbh was 4.9 +/- 3.3%. 91 patients had minor intoxication (35%), the value of COHbe was 16.4 +/- 7.9% and the value of COHbh was 7.1 +/- 4.5%, 21 patients had sever or medium intoxication (8%) the value of COHbe was 26.4 +/- 17.7% and the the value of COHbh was 12.8 +/- 9.3%. Results for COHbh were obtained for only three patients. Relationship between symptoms and expired breath carbon monoxide and relationship between symptoms and carbon monoxide blood concentration on arrival at the hospital were significant (p < 0.05).

Conclusion: Measurement of expired carbon monoxide concentration, easy and quick to perform is correlated with clinical severity in carbon monoxide poisoning.