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

Ataturk University120 enrolled

Overview

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.

Study Type

OBSERVATIONAL

Enrollment

120

Conditions

Pulmonary Embolism Acute

Interventions

thrombolytic therapyOTHER

Participants received standard clinical management according to current pulmonary embolism guidelines. No intervention was assigned by the investigators.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 80 Years

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

End-Tidal Carbon Dioxide (EtCO₂) Level at Diagnosis

EtCO₂ level measured in mmHg using nasal capnography at the time of diagnosis to assess its ability to identify high-risk and intermediate-high-risk pulmonary embolism and to predict the need for thrombolytic therapy.

Time frame: At baseline (within first 1 hour of diagnosis)