Low end-tidal carbon dioxide identifies high-severity pulmonary embolism and shock-level haemodynamics.
4 affiliations
- 1Department of Pulmonary and Critical Care, Lankenau Medical Center, Main Line Health, Wynnewood, PA, USA.
- 2Department of Interventional Cardiology, Lankenau Medical Center, Main Line Health, Wynnewood, PA, USA.
- 3Department of Emergency Medicine, Lankenau Medical Center, Main Line Health, Wynnewood, PA, USA.
- 4Main Line Health Center for Population Research, Main Line Health, Wynnewood, PA, USA.
Abstract
Background
End-tidal carbon dioxide tension (P ETCO₂ ) may be reduced when lung units are ventilated but under-perfused, as occurs in pulmonary embolism (PE). We sought to determine whether early P ETCO₂ measurement reflects PE severity according to European Society of Cardiology (ESC) risk categories and identifies shock-level haemodynamics among patients undergoing catheter-directed therapy (CDT).Methods
Patients admitted with acute PE confirmed by computed tomography pulmonary angiography were enrolled in this prospective observational study. P ETCO₂ was measured using nasal capnography within 24 h of presentation or immediately prior to urgent CDT. P ETCO₂ was compared between lower and higher severity PE groups and between patients referred for CDT or not. In patients undergoing mechanical thrombectomy (CDT) with invasive haemodynamic assessment, pulmonary arterial pressures and cardiac indices were recorded. A subgroup analysis evaluated patients with cardiogenic shock defined as cardiac index ≤1.8 L·min⁻¹·m⁻².Results
62 patients were analysed. P ETCO₂ was significantly lower in the combined higher risk group compared to the combined lower risk group (mean 21.7 (95% CI 20.2-23.3) versus 30.2 (95% CI 27.8-32.6) mmHg; p<0.001). P ETCO₂ was also lower in patients referred for CDT compared to those not referred (mean 20.4 (95% CI 18.7-22.0) versus 28.2 (95% CI 26.2-30.1) mmHg; p<0.001). Among patients who underwent CDT and met haemodynamic criteria for cardiogenic shock (n=16), P ETCO₂ was the lowest (mean 18.6 (95% CI 16.1-21.1) mmHg).Conclusions
P ETCO₂ can be rapidly obtained early in PE evaluation and reflects ESC-defined severity. A P ETCO₂ level <20 mmHg was associated with shock-level haemodynamics among normotensive intermediate-high-risk patients undergoing CDT. P ETCO₂ may serve as a non-invasive marker of physiological severity.
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BibTeX
@article{greenspon2026endtidal,
title = {{Low end-tidal carbon dioxide identifies high-severity pulmonary embolism and shock-level haemodynamics.}},
author = {Lee W Greenspon and Patrick Ho and Jason George and Spencer Whealon and Margarita Gianniosis and Betsy Develin and Jonathan Fischer and Stephanie Kjelstrom and Mara Caroline and Eric Gnall},
journal = {ERJ open research},
year = {2026},
month = sep,
doi = {10.1183/23120541.00062-2026},
url = {https://europepmc.org/article/MED/42899109},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - Low end-tidal carbon dioxide identifies high-severity pulmonary embolism and shock-level haemodynamics.
AU - Lee W Greenspon
AU - Patrick Ho
AU - Jason George
AU - Spencer Whealon
AU - Margarita Gianniosis
AU - Betsy Develin
AU - Jonathan Fischer
AU - Stephanie Kjelstrom
AU - Mara Caroline
AU - Eric Gnall
PY - 2026
DA - 2026/09/01
JO - ERJ open research
DO - 10.1183/23120541.00062-2026
UR - https://europepmc.org/article/MED/42899109
AB - Background End-tidal carbon dioxide tension (P ETCO₂ ) may be reduced when lung units are ventilated but under-perfused, as occurs in pulmonary embolism (PE). We sought to determine whether early P ETCO₂ measurement reflects PE severity according to European Society of Cardiology (ESC) risk categories and identifies shock-level haemodynamics among patients undergoing catheter-directed therapy (CDT).Methods Patients admitted with acute PE confirmed by computed tomography pulmonary angiography were enrolled in this prospective observational study. P ETCO₂ was measured using nasal capnography within 24 h of presentation or immediately prior to urgent CDT. P ETCO₂ was compared between lower and higher severity PE groups and between patients referred for CDT or not. In patients undergoing mechanical thrombectomy (CDT) with invasive haemodynamic assessment, pulmonary arterial pressures and cardiac indices were recorded. A subgroup analysis evaluated patients with cardiogenic shock defined as cardiac index ≤1.8 L·min⁻¹·m⁻².Results 62 patients were analysed. P ETCO₂ was significantly lower in the combined higher risk group compared to the combined lower risk group (mean 21.7 (95% CI 20.2-23.3) versus 30.2 (95% CI 27.8-32.6) mmHg; p<0.001). P ETCO₂ was also lower in patients referred for CDT compared to those not referred (mean 20.4 (95% CI 18.7-22.0) versus 28.2 (95% CI 26.2-30.1) mmHg; p<0.001). Among patients who underwent CDT and met haemodynamic criteria for cardiogenic shock (n=16), P ETCO₂ was the lowest (mean 18.6 (95% CI 16.1-21.1) mmHg).Conclusions P ETCO₂ can be rapidly obtained early in PE evaluation and reflects ESC-defined severity. A P ETCO₂ level <20 mmHg was associated with shock-level haemodynamics among normotensive intermediate-high-risk patients undergoing CDT. P ETCO₂ may serve as a non-invasive marker of physiological severity.
SN - 2312-0541
ER -