EIT Evaluation of Different Antihypertensive Agents on the Ventilation-Perfusion Ratio in Patients With Acute Respiratory Failure

Sponsor
First Affiliated Hospital of Wannan Medical College
Study ID
NCT07603037
Status
Not Yet Recruiting

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Conditions

  • Acute Respiratory Failure (ARF)
  • Aortic Dissection (Subset)
  • Hypertension
  • Pulmonary Perfusion Imbalance

Eligibility Criteria

Sex
ALL
Age
18 Years - N/A
Healthy Volunteers
Not accepted

Interventions

  • Nitroglycerin — DRUG
    Continuous intravenous infusion of nitroglycerin for blood pressure reduction in acute respiratory failure. The drug is administered at an initial rate of 5 µg/min, titrated up to 100 µg/min as needed to maintain target mean arterial pressure (MAP 65-85 mmHg). Each infusion period lasts 30 minutes under stable mechanical ventilation. Hemodynamic parameters, arterial blood gases, and electrical impedance tomography (EIT) data are recorded at Baseline, 30 min, and 60 min. A washout phase is observed before crossover to the second intervention.
  • Nicardipine — DRUG
    Continuous intravenous infusion of nicardipine for blood pressure control during mechanical ventilation. The infusion begins at 1 mg/h and is titrated up to 5 mg/h according to real-time blood pressure monitoring to maintain target MAP 65-85 mmHg. Each infusion period lasts 30 minutes. Electrical impedance tomography (EIT) is used to record ventilation-perfusion matching, dead-space, and shunt fraction at Baseline, 30 min, and 60 min. After completion, a 30-minute washout period or until baseline hemodynamics are restored precedes the next crossover phase.

Study Details

This prospective, single-center interventional study aims to evaluate the effect of two commonly used intravenous antihypertensive agents - nicardipine and nitroglycerin - on lung ventilation-perfusion (V/Q) distribution in patients with acute respiratory failure complicated by hypertension. Electrical Impedance Tomography (EIT) will be used for noninvasive monitoring of pulmonary ventilation and perfusion distribution before and after drug administration. The study will compare the changes in V/Q ratio, oxygenation index, and hemodynamic variables after administration of the two drugs. The findings are expected to provide evidence for the optimal antihypertensive strategy in critically ill patients with respiratory failure and to clarify whether specific vasodilators exacerbate or improve ventilation-perfusion mismatch.

Key Dates

First listed
May 22, 2026
Start date
Jul 15, 2026
Status verified
Jun 2026
Primary completion
Jul 30, 2027
Completion
Jul 30, 2027

Study Design

Enrollment
12 participants (estimated)
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE

Arms

  • Experimental: Experimental Arm: Sequential Vasodilator Infusion
    All participants will receive sequential intravenous infusions of nicardipine and nitroglycerin under controlled ICU monitoring. Drug Intervention 1: nitroglycerin Dosage: 5-100 µg/min continuous IV infusion. Duration: 30 minutes. EIT and arterial blood gas measurements will be taken before and after infusion. Drug Intervention 2: Nicardipine Dosage: 1-5 mg/h continuous IV infusion. Duration: 30 minutes. EIT and arterial blood gas measurements will be taken before and after infusion. Technique: Electrical Impedance Tomography (PulmoVista 500 or equivalent) used to obtain ventilation and perfusion maps and calculate V/Q matching indices. No placebo or parallel control arm - each subject serves as their own control in a crossover design.

Primary Outcome Measure

Change in Ventilation-Perfusion Matching Index [ Time Frame: Baseline (prior to infusion), 30 minutes after infusion initiation, 60 minutes after infusion initiation. ]

Central Contacts

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