Validation of end-tidal PCO2 and transcutaneous PCO2 as surrogates of arterial PCO2 in awake children

Abstract

Arterial blood gas analysis (ABG) is the gold standard test for carbon dioxide measurement. End-tidal PCO2 (PetCO2) and transcutaneous PCO2 (PtcCO2) are non-invasive alternative methods. Objective: to examine the use of PetCO2 and PtcCO2 as PaCO2surrogates in awake children. Methods: Prospective observational study. Consecutive awake children in stable condition referred to the Sleep Unit of Hospital de Pediatría Prof. Dr. J. P. Garrahan with suspected or confirmed SRRD requiring ABG were included. PetCO2 and PtcCO2 were recorded simultaneously during arterial puncture. PetCO2 and PtCO2 values were compared with PaCO2. Correlation coefficient and Bland-Altman analysis were applied. Sample size was calculated considering a mean difference [?] 3 mmHg as clinically acceptable. Results: 68 sample sets were obtained from 67 patients. Median age was 9.11 years (0.23-18.76). During 94.1% of the procedures patients breathed spontaneously, 30% needed