Intraoperative end-tidal carbon dioxide levels and derived calculations correlated with outcome in trauma patients
Wilson, R.F.; Tyburski, J.G.; Kubinec, S.M.; Warsow, K.M.; Larky, H.C.; Wilson, S.R.; Schermerhorn, T.
Journal of Trauma 41(4): 606-611
1996
ISSN/ISBN: 0022-5282 PMID: 8858017 Document Number: 463627
Background: To determine the relationship between the prognosis of seriously injured patients requiring emergency surgery and intraoperative end-tidal CO-2 variables and "excess P-CO-2." Method: Retrospective chart review of 100 seriously injured patients admitted to Detroit Receiving Hospital and requiring major surgery (mortality rate of 40%). Standard intraoperative monitoring, including continuous capnography, plus arterial blood analyses every 15 to 30 minutes during surgery. Results: After resuscitation for 45 to 90 minutes, 11 patients had a systolic blood pressure lt 100 mm Hg and, of these patients, 10 (91%) died. Of the remaining 89 patients, mortality rates were 53% (16/30), with an end-tidal CO-2 of 22 mm Hg or less, versus 24% (14/59) with an end-tidal CO-2 of 23 mm Hg or more (p = 0.011). An arterial to end-tidal P-CO-2 difference of 13 mm Hg or more after resuscitation was associated with an increased mortality rate (50% (20/34 vs. 18% (20/55)) (p lt 0.005). The mortality rate was particularly high, with a final arterial to end-tidal P-CO-2 difference of 12 mm Hg or more (73% (30/41) versus 17% (10/59) (p lt 0.001)). A final Pa-CO-2 excess (i.e., the amount by which the Pa-CO-2 was higher than expected from the bicarbonate) gt 1.0 mm Hg was also associated with an increased mortality rate ((62% (33/53) vs. 15% (7/47)) (p lt 0.001). Conclusion: Values derived from the end-tidal CO-2 and the excess P-CO-2 should be monitored intraoperatively in critically injured patients. Efforts should be made to improve cardiac output and adjust ventilation to maintain an end-tidal P-CO-2 of 25 mm Hg or more, an arterial to end-tidal CO-2 difference of 12 mm Hg or less, and an excess Pa-CO-2 of 1.0 mm Hg or less.