Saline Contrast Electrical Impedance Tomography Method for Diagnosis of Acute Pulmonary Embolism

Condition(s) studied

Investigational drug(s) / intervention(s)

Saline contrast Electrical Impedance Tomography method: This study will enroll patients with clinically suspected or confirmed acute pulmonary embolism (PE) presenting with acute respiratory failure, who undergo electrical impedance tomography (EIT) with saline contrast within 24 hours before or after computed tomography pulmonary angiography (CTPA). The EIT procedure is performed as follows: 1. Breath-Hold Maneuver: (1)Spontaneous breathing patients: Supine position, instructed to hold expiration for ≥8 seconds. (2)Mechanically ventilated patients: Expiratory hold (\>8 sec) achieved via ventilator; deeper sedation will be applied when feasible to prolong breath-hold. 2. Venous Access: (1)Preferred: Central venous catheter (internal jugular or subclavian vein).(2)Alternative: Peripheral forearm vein (preferably the median cubital vein). 3. Contrast Administration:(1)Central venous route: 10 mL of 10% NaCl.(2)Peripheral venous route: 15 mL of 5% NaHCO₃.

Computed Tomography Pulmonary Angiography (CTPA): Patients who meet the inclusion criteria will undergo CTPA examination using conventional clinical diagnostic methods.

Study summary

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

Primary outcome measure(s)

• The ability of proportion of dead space ventilation to diagnose PE — Within 24 hours before or after the CTPA examination
  The participant undergoes a saline contrast EIT examination, after which the distribution of pulmonary ventilation and perfusion will be obtained, respectively. A V-Q map will be subsequently generated. Using offline EIT data analysis tool, the proportion of lung regions with ventilation but without perfusion is calculated, representing the proportion of dead space ventilation (expressed as a percentage). Area under the receiver operating characteristic curve (AUROC), sensitivity, specificity, Youden's index, accuracy, Kappa statistic, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR) and negative likelihood ratio (NLR) will be used to evaluate the ability of proportion of dead space ventilation to diagnose acute pulmonary embolism (PE).

Trial sites (1)

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