Cardiologia Clínica e Experimental
Acesso livre

Abstrato

Combined Use of Transcutaneous and End-Tidal Measures of Carbon Dioxide to Predict PCO2 during General Anaesthesia in Adults

Yongming Cai, Faling Yi, Man Luo, DeYu Tang, and Xianfa Cai

Background: The aim of the present study was to integrate PtcCO₂ and PetCO₂ models to improve the accuracy and precision of PCO₂ measurements.

Methods: 26 ASA physical status I-III postoperative patients recovering from general anesthesia after surgery were selected for investigation. The carbon dioxide partial pressure (PCO₂) levels were determined six times during the anesthesia of each patient by using arterial blood gas analysis (PaCO₂), end-tidal (PetCO₂) and transcutaneous (PtcCO₂) measurements. This study tested the hypothesis that combining PetCO₂ and PtcCO₂ measurements by a regression function, namely Pet_tcCO₂, will improve PCO₂ measurements during sedation. The Bland-Altman method was used for the statistical analysis, and a p<0.05 was considered statistically significant. Results: A total of 156 data sets (i.e., PaCO₂, PetCO₂, and PtcCO₂) were obtained from 26 patients (63 ± 17 years old; 18 males, 8 females). The mean PaCO₂ was 44.3 ± 3.88 mm Hg. The mean PetCO₂ was 38.9 ± 4.01 mm Hg. The mean PtcCO₂ level was 46.1 ± 3.95 mm Hg. The average PtcCO₂-PaCO₂ difference was 3.8 ± 1.85 mm Hg. The average PetCO2-PaCO₂ difference was -3.9 ± 1.95 mm Hg. When the value of Pet_tcCO₂ were combined, the fit equation was Pet_tcCO₂=7.24+0.36 × PetCO₂+0.46 × PtcCO₂, R2= .66, p<0.001. The average Pet_tcCO₂-PaCO₂ difference was 2.1 ± 1.25 mm Hg.

Conclusions: The combined use of transcutaneous and end-tidal methods could help improve the accuracy and precision of PCO₂ measurements. Pet_tcCO₂ approach of combining PetCO₂ and PtcCO₂ techniques could be a new technology for PCO₂ measurement in spontaneously breathing patients have no serious lung disease.