Effect of Nicardipine and Nitroglycerin on the Ventilation-Perfusion Ratio in Patients With Acute Respiratory Failure Using Electrical Impedance Tomography: A Prospective Pilot Study
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 发起方
- 入组人数
- 12
- 试验地点
- 1
研究概览
简要总结
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.
详细描述
Eligible adult patients diagnosed with acute respiratory failure (PaO₂/FiO₂ ≤ 300 mmHg) and concomitant hypertension (including post-surgical or aortic dissection cases) admitted to the ICU will be enrolled after stabilization.
After baseline EIT and blood gas measurements, participants will sequentially receive nitroglycerin and nicardipine under controlled conditions, with each medication infused over a standardized time period while continuously monitoring vital signs.
EIT-derived ventilation and perfusion images will be acquired at baseline, 30 minutes after nitroglycerin, and 30 minutes after nicardipine.
The primary endpoint is the change in the regional ventilation-perfusion matching index (V/Q-MI). Secondary endpoints include changes in oxygenation, arterial blood gases, and hemodynamic parameters.
All data will be statistically analyzed using paired comparisons and multivariate regression to assess drug-specific effects on pulmonary gas exchange.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Diagnosis of acute respiratory failure with PaO₂/FiO₂ ≤ 300 mmHg, requiring invasive mechanical ventilation.
- •Requires intravenous antihypertensive infusion (such as nicardipine or nitroglycerin) to maintain controlled and stable blood pressure during ICU treatment.
- •Written informed consent obtained from the patient or the legally authorized representative.
排除标准
- •Body mass index (BMI) ≥ 50 kg/m² or presence of massive subcutaneous edema interfering with EIT signal acquisition.
- •Implanted cardiac pacemaker, defibrillator, or any metallic thoracic device that may distort impedance measurements.
- •Hemodynamic instability or severe hypotension occurring during drug titration. Pregnancy or lactation. Known hypersensitivity or contraindication to nicardipine or nitroglycerin. Use of phosphodiesterase-5 inhibitors, such as sildenafil, tadalafil, or vardenafil, within the clinically relevant washout period.
- •Severe anemia, markedly increased intracranial pressure, or other clinical conditions in which nitroglycerin administration is considered inappropriate by the treating physician.
- •Incomplete clinical documentation preventing accurate evaluation of primary endpoints.
研究组 & 干预措施
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.
干预措施: Nitroglycerin (Drug)
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.
干预措施: Nicardipine (Drug)
研究者
Qiancheng Xu
Principal Investigator
First Affiliated Hospital of Wannan Medical College