Overview

The goal of this observational study is to compare the consistency of saline contrast Electrical Impedance Tomography(EIT) method and Computed Tomography Pulmonary Angiography (CTPA) in diagnosing acute pulmonary embolism. The main question it aims to answer is:

Can bedside saline contrast EIT method be used for the diagnosis of acute pulmonary embolism? The participants will undergo saline contrast EIT and CTPA examinations successively within 24 hours.

Eligibility

Inclusion Criteria:

1. Patients with clinically suspected or confirmed acute pulmonary embolism (PE) presenting with acute respiratory failure;
2. Availability of CTPA results within 24 hours or scheduled to undergo CTPA within the next 24 hours;
3. Age >18 years; no gender restrictions;
4. Presence of central venous access (internal jugular or subclavian vein) or peripheral forearm venous access;
5. Willingness to participate with signed informed consent from either the patient or legal guardian.

Exclusion Criteria:

1. Pregnancy or lactation;
2. Relative contraindications to EIT examination (e.g., chest wall wounds at electrode belt placement site, presence of pacemakers);
3. Severe hypernatremia (serum sodium >155 mmol/L);
4. Inability to maintain expiratory breath-hold for ≥8 seconds;
5. BMI >50 or severe thoracic deformities;
6. Current extracorporeal membrane oxygenation (ECMO) therapy.