Intraoperative end-tidal carbon dioxide values and derived calculations correlated with outcome: prognosis and capnography
Domsky, M.; Wilson, R.F.; Heins, J.
Critical Care Medicine 23(9): 1497-1503
1995
ISSN/ISBN: 0090-3493 PMID: 7664551 Document Number: 440216
Objective: To determine how much information concerning resuscitation and outcome is provided by the end-tidal CO-2 and derived variables obtained during surgery. Design: Retrospective chart review. Setting: Emergency hospital operating room. Patients: One hundred critically ill or injured patients requiring major surgery and having a mortality rate of 41%. Interventions: Standard intraoperative monitoring, including continuous capnography, plus arterial blood gas analyses every 1 to 1.5 hrs during surgery. Measurements and Main Results: There was only a fair correlation between the PaCO-2 and end-tidal CO-2 (r-2 = .14). The mortality rates in these patients were highest in those patients who had the lowest end-tidal CO-2 values, the highest arterial to end-tidal CO-2 differences, and the highest estimated alveolar deadspace fraction. A persistent end-tidal CO-2 of ltoreq 28 torr ( ltoreq 3.8 kPa) was associated with a mortality rate of 55% (vs. 17% in those patients with a higher end-tidal CO-2). The mortality rate was also increased in patients with a persistent arterial to end-tidal CO-2 difference of gtoreq 8 torr ( gtoreq 1.1 kPa) (58% vs. 23%). Conclusions: End-tidal CO-2 and derived values should be monitored closely in critically ill or injured patients. Efforts should be made-by increasing cardiac output and core temperature and by adjusting ventilation as needed-to maintain the end-tidal CO-2 at gtoreq 29 torr ( gtoreq 3.9 kPa) and the arterial to end-tidal CO-2 difference at ltoreq 7 torr ( gtoreq 1.0 kPa).