title: Noninvasive carbon dioxide monitoring during one-lung ventilation: end-tidal versus transcutaneous techniques.
abstract: OBJECTIVE
  To compare transcutaneous CO(2) (TCCO(2)) and end-tidal CO(2) (ETCO(2)) monitoring during one-lung ventilation (OLV).
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Operating room of a University Hospital.
  
  
  METHODS
  Fifteen patients undergoing thoracic surgical procedures in whom one-lung ventilation was deemed necessary.
  
  
  METHODS
  TC and ETCO(2) monitors were used simultaneously in the patients and compared with arterial blood gases (ABGs) during 2-lung ventilation and OLV.
  
  
  RESULTS
  During 2-lung ventilation (TLV), the ET to PaCO(2) difference was 3.9 +/- 1.6 mmHg, whereas the TC to PaCO(2) difference was 2.5 +/- 0.8 mmHg (p = 0.0049). During OLV, the ET to PaCO(2) difference increased to 5.8 +/- 2.3 mmHg, whereas the TC to PaCO(2) difference was 2.7 +/- 1.4 mmHg (p = 0.0049 for ET to PaCO(2) difference during OLV v TLV and p = 0.0004 for ET to PaCO(2) gradient v TC to PaCO(2) gradient during OLV). During TLV, the difference between the ET and PaCO(2) was < or = 5 mmHg in 13 of 15 patients, whereas the difference between the TC and PaCO(2) was < or = 5 mmHg in 15 of 15 patients (p = not significant). During OLV, the difference between the ET and the PaCO(2) was < or = 5 mmHg in 6 of 15 patients, whereas the difference between the TC and PaCO(2) was < or = 5 mmHg in 14 of 15 patients (p = 0.0052, odds ratio 21.0 for ET v TC techniques and p = 0.02, odds ratio 9.75 for ET to PaCO(2) during TLV v OLV).
  
  
  CONCLUSIONS
  During OLV, TCCO(2) monitoring provides a more accurate estimate of PaCO(2) than ET techniques.
authors.affiliation: Department of Anesthesiology and Pediatrics, The University of Missouri, Columbia, MO 65212, USA. Tobiasj@health.missouri.edu
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Tobias
mesh_terms: D000293:Adolescent; D000328:Adult; D001785:Blood Gas Monitoring, Transcutaneous; D002245:Carbon Dioxide / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D006801:Humans; D016343:Monitoring, Intraoperative; D011446:Prospective Studies; D012121:Respiration, Artificial; D019616:Thoracic Surgical Procedures; D013990:Tidal Volume / Q000502:physiology
chemical_list: D002245:Carbon Dioxide