title: Noninvasive intraoperative monitoring of carbon dioxide in children: endtidal versus transcutaneous techniques.
abstract: BACKGROUND
  The current study prospectively compares the accuracy of the intraoperative use of transcutaneous (Tc) and endtidal (PE) CO2 monitoring during surgical procedures in 30 paediatric patients, ranging in age from 6 months to 15 years (6.15 +/- 4.35 years) and in weight from 4.7 to 73 kg (24.9 +/- 18.2 kg).
  
  
  METHODS
  Following calibration and an equilibration time for the TcCO2 monitor, arterial blood gas samples were obtained as clinically indicated. A total of 64 sample sets (PaCO2, PECO2 and TcCO2) were obtained from the 30 patients.
  
  
  RESULTS
  The PECO2 to PaCO2 difference was 0.6-0.9 kPa (4.4 +/- 7.1 mmHg) while the TcCO2 to PaCO2 difference was 0.36-0.38 kPa (2.8 +/- 2.9 mmHg) (P=NS). The difference between the PaCO2 and PECO2 was 0.4 kPa (3 mmHg) or less in 37 of 64 sample sets while the difference between the PaCO2 and TcCO2 was 0.4 kPa (3 mmHg) or less in 49 of 64 sample sets (P=0.038). Linear regression analysis of PECO2 vs. PaCO2 revealed a slope of 0.434, r=0.8761, r2=0.7676. Linear regression analysis of TcCO2 vs. PaCO2 revealed a slope of 0.914, r=0.9472, r2=0.8972.
  
  
  CONCLUSIONS
  Although in most circumstances, both noninvasive monitors of PCO2 provided a clinically acceptable estimate of PaCO2, TCCO2 provided a slightly more accurate estimate of PaCO2 during intraoperative anaesthetic care in children.
authors.affiliation: Departments of Child Health and Anesthesiology, The University of Missouri, Columbia, MO 65212, USA.
authors.forename: Mace A
authors.initials: MA
authors.lastname: Nosovitch
authors.forename: Joel O
authors.initials: JO
authors.lastname: Johnson
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Tobias
mesh_terms: D000768:Anesthesia, General; D001785:Blood Gas Monitoring, Transcutaneous; D002245:Carbon Dioxide / Q000097:blood*; D002648:Child; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D016343:Monitoring, Intraoperative; D011446:Prospective Studies; D012121:Respiration, Artificial
chemical_list: D002245:Carbon Dioxide