Differences Between End-Tidal Carbon Dioxide Obtained in Right and Left Lateral Decubitus Positions in a Patient With a Pulmonary Embolism – A Concept for Usage in Emergency Medicine

Abstract

The aim: To diagnose patients with suspected pulmonary embolism is to assess eTCO2 in two lateral decubitus positions and to compare them between each other and with PaCO2. Material and methods: An approval of the bioethics commission was obtained to study eTCO2 in different positions in patients with suspected PE (583/2019). Consecutive ED patients referred for computed tomography pulmonary angiography (CTPA) due to a suspicion of pulmonary artery embolism are asked to take part in the study. Exclusion criteria are the inability to give informed consent, shock or hypotension, inability to change position (an elevation of the upper body to 30 degrees is allowed). The other available laboratory data like D-dimer concentration, troponin, arterial blood gases analysis, creatinine, sodium, potassium, NT-proBNP, hemoglobin, C-reactive protein, and glycemia are noted. CTPA in the case of pulmonary embolism is assessed to determine differences between embolism to both lungs. Results: The difference between eTCO2 on the left lateral decubitus position was found. Contrary to this finding in a healthy person there was no differences between eTCO2 obtained in both lateral positions. Stress tests are known methods for examining patients whose underlying conditions are normal or inconclusive. In the case of capnography, such a load could be a change in body position, which is a simple procedure that does not require much physical effort. Conclusions: Intensifying efforts to disseminate knowledge on the use of eTCO2 in clinical practice and to find new applications for this study seems particularly important.