title: Accuracy of end-tidal PCO2 measurements using a sidestream capnometer in infants and children ventilated with the Sechrist infant ventilator.
abstract: To determine the accuracy of end-tidal PCO2 (PETCO2) measurements analyzed with a sidestream capnometer in infants and children whose lungs were ventilated with a Sechrist infant ventilator and an Ayre's t-piece, we compared PETCO2 measurements obtained from the proximal (PETCO2-p) and distal (PETCO2-d) ends of the tracheal tube to arterial PCO2 (PaCO2) in 37 healthy infants and children between 1.3 and 24.5 kg. Both PETCO2-p and PETCO2-d accurately approximated PaCO2, however, the mean (+/- SD) arterial to end-tidal PCO2 difference (delta(a-ET)PCO2) was significantly greater with proximal (1.27 +/- 1.54 mmHg) than with distal sampling (0.64 +/- 1.64 mmHg) (P less than 0.01). In the subgroup of patients who weighted less than 12 kg, the delta(a-ET)PCO2 using proximal gas sampling (1.94 +/- 1.29 mmHg) was also significantly greater than it was using distal sampling (0.74 +/- 1.31 mmHg) (P less than 0.001). We conclude that although statistically different, both proximal and distal estimates of PETCO2 provide acceptable estimates of PaCO2 in healthy infants and children who are ventilated with a Sechrist infant ventilator and an Ayre's t-piece system.
authors.affiliation: Department of Anaesthesia, Hospital for Sick Children, University of Toronto, Ontario, Canada.
authors.forename: S C
authors.initials: SC
authors.lastname: Hillier
authors.forename: J M
authors.initials: JM
authors.lastname: Badgwell
authors.forename: M E
authors.initials: ME
authors.lastname: McLeod
authors.forename: R E
authors.initials: RE
authors.lastname: Creighton
authors.forename: J
authors.initials: J
authors.lastname: Lerman
mesh_terms: D002245:Carbon Dioxide / Q000097:blood*; D002675:Child, Preschool; D005069:Evaluation Studies as Topic; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D010313:Partial Pressure; D013147:Spirometry / Q000295:instrumentation*; D012122:Ventilators, Mechanical
chemical_list: D002245:Carbon Dioxide