Relationship between Arterial and End-tidal CO2 Tensions in Anesthetized Infants and Children

Lee, Sang Chul; Cho, Myung Won

Abstract

End-tidal (PETCO2) and arterial CO2, tensions (PaCO2) were measured in 66 anesthetized infants and children. 35 patients were under 7 year-old (group 1) and 31 patients were over 7 year-old (group 2). In both groups, differences between PETCO2, and PaCO2, were evaluated, and correlations between PETCO2, and PaCO2, were carried out. The children in group 1 had a PaCO2, (mean+/-S.D.) of 29.2+/-4.1mmHg and a PCO2, (mean+/-S,D.) of 29.2+4.1mmHg. The range of the PaCO2, and PETCO2 difference (P alpha-ETCO2) was from -1.0 to 1.2 mmHg. The children in group 2 had a PaCO2 (mean+/-S.D.) of 29.3+/-3.0 mmHg and a PETCO2 (mean+/-S.D.) of 29.3+/-4.0mmHg. The range of the P alpha-ETCO2 was from 1.9 to 2.5mmHg. The significant direct correlations between PaCO2 and PETCO2 in both groups (r=0.96,0.84, respec-tively) were defined. The difference between groups wasnt statistically significant. It is concluded that in normal infants and children during anesthesia, noninvasive measurement of PET CO2 can be used as a reliable estimate of PaCO2 and that PETCO2did not differ significantly from PaCO2.