title: Intraoperative end-tidal carbon dioxide levels and derived calculations correlated with outcome in trauma patients.
abstract: BACKGROUND
  To determine the relationship between the prognosis of seriously injured patients requiring emergency surgery and intraoperative end-tidal CO2 variables and "excess Pco2."
  
  
  METHODS
  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 < 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 CO2 of 22 mm Hg or less, versus 24% (14/59) with an end-tidal CO2 of 23 mm Hg or more (p = 0.011). An arterial to end-tidal Pco2 difference of 13 mm Hg or more after resuscitation was associated with an increased mortality rate (50% (20/34 vs. 18% (20/55)) (p < 0.005). The mortality rate was particularly high, with a final arterial to end-tidal Pco2 difference of 12 mm Hg or more (73% (30/41) versus 17% (10/59) (p < 0.001). A final Paco2 excess (i.e., the amount by which the Paco2 was higher than expected from the bicarbonate) > 1.0 mm Hg was also associated with an increased mortality rate ((62% (33/53) vs. 15% (7/47)) (p < 0.001).
  
  
  CONCLUSIONS
  Values derived from the end-tidal CO2 and the excess Pco2 should be monitored intraoperatively in critically injured patients. Efforts should be made to improve cardiac output and adjust ventilation to maintain an end-tidal Pco2 of 25 mm Hg or more, an arterial to end-tidal CO2 difference of 12 mm Hg or less, and an excess Paco2 of 1.0 mm Hg or less.
authors.affiliation: Department of Surgery, Detroit Receiving Hospital, MI 48201, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Wilson
authors.forename: J G
authors.initials: JG
authors.lastname: Tyburski
authors.forename: S M
authors.initials: SM
authors.lastname: Kubinec
authors.forename: K M
authors.initials: KM
authors.lastname: Warsow
authors.forename: H C
authors.initials: HC
authors.lastname: Larky
authors.forename: S R
authors.initials: SR
authors.lastname: Wilson
authors.forename: T
authors.initials: T
authors.lastname: Schermerhorn
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000032:analysis* / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D011379:Prognosis; D012126:Respiratory Dead Space; D015657:Respiratory Transport; D012189:Retrospective Studies; D015996:Survival Rate; D014947:Wounds and Injuries / Q000097:blood / Q000401:mortality* / Q000503:physiopathology* / Q000601:surgery
chemical_list: D002245:Carbon Dioxide