Acute respiratory distress syndrome is a severe respiratory failure that causes pulmonary edema and decreased lung compliance due to increased alveolar–vascular permeability, resulting in severe hypoxemia and hypercapnia. Because its mortality rate ...
Acute respiratory distress syndrome is a severe respiratory failure that causes pulmonary edema and decreased lung compliance due to increased alveolar–vascular permeability, resulting in severe hypoxemia and hypercapnia. Because its mortality rate is high, early diagnosis and ventilatory management are important, and real-time respiratory monitoring is essential especially in mechanically ventilated patients. Capnography is a tool that evaluates ventilatory status by continuously measuring end-tidal carbon dioxide tension in a noninvasive manner, and can indirectly predict arterial carbon dioxide tension. However, in patients with acute respiratory distress syndrome, the correlation between these two indicators changes due to increased dead space. The prone position, which is the main treatment for acute respiratory distress syndrome, is effective in improving oxygenation; however, its effect on carbon dioxide elimination remains controversial. Therefore, identifying the relationship between arterial carbon dioxide tension and end-tidal carbon dioxide tension in the prone position has important implications for assessing ventilatory efficiency and disease severity. This study aimed to identify the correlation and influencing factors between arterial carbon dioxide tension and end-tidal carbon dioxide tension in patients with acute respiratory distress syndrome in the prone position, in order to provide evidence for nurses to evaluate ventilatory status in real time and perform immediate interventions using noninvasive indicators.
This study was a retrospective correlational study conducted to identify the correlation and influencing factors between arterial carbon dioxide tension and end-tidal carbon dioxide tension in 146 patients who were admitted to the medical intensive care unit of a tertiary hospital in Seoul between January 1, 2020 and December 31, 2024, had acute respiratory distress syndrome, and underwent prone positioning. Data collection was performed using electronic medical records and the data warehouse SUPREME 2.0, and included general characteristics, disease-related characteristics, and arterial and end-tidal carbon dioxide tension at each time point. The collected data were analyzed using SPSS version 26.0, and Friedman test, Spearman rank correlation analysis, and generalized estimating equations (GEE) were used according to the study purpose.
The results of this study were as follows.
1. There was no statistically significant difference in the difference between arterial carbon dioxide tension and end-tidal carbon dioxide tension according to measurement time points.
2. Significant positive correlations were found between arterial carbon dioxide tension and end-tidal carbon dioxide tension at all measurement time points.
3. There was no statistically significant difference in the difference between arterial carbon dioxide tension and end-tidal carbon dioxide tension according to general characteristics of the patients.
4. Regarding disease-related characteristics, the difference between arterial carbon dioxide tension and end-tidal carbon dioxide tension was significantly increased when the cause of acute respiratory distress syndrome was pulmonary.
This study analyzed the correlation and influencing factors between arterial carbon dioxide tension and end-tidal carbon dioxide tension in patients with acute respiratory distress syndrome in the prone position. As a result of the study, it was confirmed that end-tidal carbon dioxide tension can appropriately reflect arterial carbon dioxide tension in the prone position, and it provided a basis for nurses to evaluate the patient's clinical status and support clinical decision-making through nurse-led continuous carbon dioxide monitoring. In addition, this study is meaningful in that it empirically presented the relationship between arterial carbon dioxide tension and end-tidal carbon dioxide tension in the prone position in patients with acute respiratory distress syndrome, which has not been addressed in previous literature.
Future studies are expected to conduct additional research considering various patient characteristics and the duration of prone positioning, and to develop nurse-led end-tidal carbon dioxide-based monitoring protocols based on these findings.