title: Comparison of a sidestream and mainstream capnometer in infants.
abstract: This study was designed to compare capnograms obtained from a sidestream and mainstream capnometer during rapid mechanical ventilation in infants. Ten infants were studied during elective anesthesia and surgery. Simultaneous recordings of exhaled CO2 were made with a sidestream and a mainstream machine; arterial blood gases were measured for comparison. The mean arterial to end-tidal CO2 difference (PaCO2-PetCO2) was approximately 5 torr with either technique; the correlation of PetCO2 with PaCO2 was slightly better with the mainstream analyzer (r2 = .895 vs. .654). The recordings obtained with the sidestream machine were grossly distorted, with flattening of the ascending limb (slope 37.3 vs. 153.3 torr/sec, sidestream vs. mainstream, p less than .001) and absence of the alveolar plateau. The mainstream analyzer gives a more accurate representation of the expired CO2 waveform in small children at rapid respiratory rates.
authors.affiliation: Department of Anesthesia, Children's Hospital, Boston, MA 02115.
authors.forename: R C
authors.initials: RC
authors.lastname: Pascucci
authors.forename: J A
authors.initials: JA
authors.lastname: Schena
authors.forename: J E
authors.initials: JE
authors.lastname: Thompson
mesh_terms: D002245:Carbon Dioxide / Q000502:physiology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D012119:Respiration; D012121:Respiration, Artificial / Q000295:instrumentation*
chemical_list: D002245:Carbon Dioxide