Using End-Tidal CO₂ to Help Diagnose and Monitor Pulmonary Embolism

Ataturk University

Status: Completed

Conditions: Pulmonary Embolism Acute

Treatments: Other: thrombolytic therapy

Study type: Observational

Funder types: Other

Identifiers

NCT07241130

B.30.2.ATA.0.01.00/427

Details and patient eligibility

About

Pulmonary embolism (PE) can reduce blood flow in the lungs and impair gas exchange, leading to lower end-tidal carbon dioxide (EtCO₂) levels. This prospective observational study aims to evaluate whether EtCO₂ can help identify high-risk and intermediate-high-risk patients and monitor early treatment response, especially during thrombolytic therapy. A total of 120 participants were included: high-risk PE, intermediate-high-risk PE patients who received thrombolysis, intermediate-high-risk PE patients treated only with anticoagulation, and healthy controls.

The study measured EtCO₂ along with oxygen saturation, heart rate, respiratory rate, perfusion index, and radiological obstruction scores. By comparing these parameters at diagnosis and during the first 24 hours, the study seeks to determine whether EtCO₂ can serve as a simple, noninvasive marker of disease severity and early hemodynamic improvement in patients with acute PE.

Enrollment: 120 patients

Sex: All

Ages: 18 to 80 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

Adults aged 18 years or older Diagnosis of acute pulmonary embolism confirmed by CT pulmonary angiography (for PE groups) Classified as high-risk or intermediate-high-risk pulmonary embolism according to ESC/ERS 2019 guidelines Ability to provide informed consent For healthy control group: no history of cardiopulmonary disease, coagulation disorders, or acute medical illness

Exclusion criteria

Known chronic respiratory diseases significantly affecting EtCO₂ measurement (e.g., advanced COPD, severe asthma, chronic respiratory failure) Active infection, sepsis, or acute complications of malignancy Prior thrombolytic therapy for pulmonary embolism Anatomical or technical limitations preventing reliable nasal capnography Pregnancy Individuals younger than 18 years Inability or refusal to provide informed consent

Trial design

120 participants in 4 patient groups

Group 1: High-Risk Pulmonary Embolism (Thrombolysis)

Description:

Patients presenting with shock or persistent hypotension and receiving systemic thrombolytic therapy.

Treatment:

Other: thrombolytic therapy

Group 2: Intermediate-High-Risk Pulmonary Embolism (Thrombolysis)

Description:

Hemodynamically stable patients with RV dysfunction and elevated biomarkers who required thrombolysis.

Treatment:

Other: thrombolytic therapy

Group 3: Intermediate-High-Risk Pulmonary Embolism (Non-Thrombolysis)

Description:

Patients meeting intermediate-high-risk criteria but treated with anticoagulation only.

Group 4: Healthy Controls

Description:

Individuals without cardiopulmonary disease and with normal clinical and laboratory findings.