SEMIQUANTITATIVE CAPNOMETRY - USEFUL IN T HE VERIFICATION OF ENDOTRACHEAL-TUBE PLACEMENT IN TRAUMA PATIENTS

Severely injured patients, in particular, benefit from initiation of e ndotracheal intubation and controlled ventilation before hospital admi ssion. The most frequent and most serious mishap of this emergency pro cedure is inadvertent esophageal tube placement. A reliable and simple determination of proper tube placement involves capnometry, the measu rement of carbon dioxide concentration during the respiratory cycle. T he purpose of this study was to evaluate the dependability of semi-qua ntitative capnometry in verifying proper tube placement in the prehosp ital treatment of trauma patients. First, we determined and tested the suitability of the equipment used in this study (STAT CAP) in 40 pati ents under controlled hospital conditions; subsequently, we tested it under prehospital conditions on 40 trauma patients. Within the two stu dy groups, the STAT CAP proved to be of high sensitivity (1.0) and spe cificity (1.0) in identifying tracheal tube position immediately after intubation manoeuvre, even in patients with a shock index >1 (n = 14) and patients with cardiac arrest (n = 3). In cases of tracheal tube p osition, a CO2 signal was noted after two ventilations, on average, in both study groups. The average initial CO2 value recorded amongst the hospital study group was 30-50 mmHg, against 20-30 mmHg in the prehos pital trauma group. The traditional signs used to verify endotracheal tube placement (direct visualization of the cords and auscultation of sounds upon the chest) failed in three cases amongst the prehospital t rauma group; in all of these cases the STAT CAP detected the (tracheal ) tube placement correctly. We conclude that the STAT CAP reliably det ects tracheal placement of endotracheal tube in non-arrested patients. In the arrested patient, interpretation of CO2 nonappearance requires caution. In addition to the traditional clinical signs, semi-quantita tive capnometry is a meaningful supplement to verify tracheal tube pla cement in the prehospital management of trauma patients.