Abstract
Background: Correlation and agreement of Transcutaneous capnography carbon dioxide (TcCO2) with arterial carbon dioxide pressure (PaCO2) have been studied before, mostly in neuromuscular, COPD or acute respiratory failure patients.
Aims and Objectives: To determine the correlation and agreement of nocturnal TcCO2 with gold standard in patients with Obesity hypoventilation syndrome (OHS).
Methods: Observational and prospective study of consecutive OHS patients in stable condition, from June of 2019 to January of 2020. A 7-hour record of TcCO2 was performed, with a temperature of 42ºC, and in 94% of cases the electrode was placed with an ear clip. PaCO2 was measured at 4 am. COPD, neuromuscular and thoracic restrictive patients were excluded. Corrected drift measurement at the time of arterial blood gas extraction was considered for the study. Correlation was assessed by the Pearson's statistic, while agreement by Intraclass correlation coefficients (ICC) in a two factors, random events model. Furthermore, Bland-Altman plot analysis was also obtained, and regression linear analysis for ruling out proportional bias.
Results: Eighteen OHS patients were included, 13 women and 5 men, with a mean age of 66.7 ± 14.3 years and a mean BMI of 39.1 ± 8.6 kg/m2. Mean TcCO2 was 43.9 ± 12.9 mmHg and mean PaCO2 47.3 ± 14.2 mmHg. Correlation of TcCO2 and PaCO2 was of 0.944 (CI95% 0.824 - 9.823, p=0.0001), and CCI of 0.956 (CI95% 0.813 - 0.986, p=0.0001). Bland Altman plot is presented in Figure 1, no proportional bias was found (t value -1.17, p=0.257).
Conclusions: Very strong correlation and agreement was observed between TcCO2 and PaCO2 measurements in OHS patients.
Footnotes
Cite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 2134.
This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2020