Acute Respiratory Failure (ARF)NCT07603037
EIT Evaluation of Different Antihypertensive Agents on the Ventilation-Perfusion Ratio in Patients With Acute Respiratory Failure
A study testing Nitroglycerin and Nicardipine in people with Acute Respiratory Failure (ARF) and Hypertension, run by First Affiliated Hospital of Wannan Medical College at 1 site in China.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Acute Respiratory Failure (ARF), Hypertension, Pulmonary Perfusion Imbalance
- What is being tested?
- Nitroglycerin and Nicardipine
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- 1 siteChina
- Study dates
- 15 Jul 2026to 30 Jul 2027
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
None listed.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
China1 site
The First Affiliated Hospital of Wannan Medical College (Yijishan Hospital of Wannan Medical College)
Wuhu, Anhui, 241001
Shengsheng Tao, 86-18315329399, taoshengsheng@yjsyy.com
About this study
Official title: Effect of Nicardipine and Nitroglycerin on the Ventilation-Perfusion Ratio in Patients With Acute Respiratory Failure Using Electrical Impedance Tomography: A Prospective Pilot Study
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.
Read the detailed description
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.
- Conditions
- Acute Respiratory Failure (ARF), Hypertension, Pulmonary Perfusion Imbalance, Aortic Dissection (Subset)
- Being tested
- Nitroglycerin, Nicardipine
- Keywords
- Electrical Impedance Tomography, Ventilation-Perfusion Ratio, Nicardipine, Acute Respiratory Failure, Intensive Care Unit, Nitroglycerin
- Medical subject headings
- Hypertension, Aortic Dissection
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
NitroglycerinDrug
Also called Glyceryl Trinitrate; Nitroglycerin Injection; Tridil®
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.
NicardipineDrug
Also called Cardene; Nicardipine Hydrochloride
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 group | Role | What they receive |
|---|---|---|
| Experimental Arm: Sequential Vasodilator Infusion | Experimental | 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. Receives: Drug: Nitroglycerin; Drug: Nicardipine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Ventilation-Perfusion Matching Index
The ventilation-perfusion matching index quantifies the correlation between regional ventilation and perfusion signals derived from EIT imaging. The index ranges from 0 to 1; higher values indicate better matching.
Measured: Baseline (prior to infusion), 30 minutes after infusion initiation, 60 minutes after infusion initiation.
Change in Physiological Dead Space Fraction (Vd/Vt)
Physiological dead space is calculated as (PaCO₂ - PeCO₂)/PaCO₂, supplemented by EIT-based regional ventilation analysis. The expected range is 0 to 0.8; higher values indicate greater alveolar wastage and poorer gas exchange.
Measured: Baseline, 30 minutes, and 60 minutes.
Change in Intrapulmonary Shunt Fraction (%)
The shunt fraction represents the percentage of non-oxygenated blood flowing through the lungs without gas exchange. It is computed as Qs/Qt = (CCO₂ - CaO₂) / (CCO₂ - CvO₂), approximated by EIT regional perfusion measurement. Typical range 0-40 %; higher values indicate worse oxygenation efficiency.
Measured: Baseline, 30 minutes, and 60 minutes.
Secondary outcomes (3)
Change in Pulmonary Perfusion Distribution
Regional perfusion ratio analyzed via EIT contrast impedance variation after saline bolus indicator; expressed as percentage of dependent to non-dependent lung regions. Higher ratios reflect more homogeneous perfusion.
Measured: Baseline, 30 minutes, and 60 minutes.
Change in Pulmonary Ventilation Distribution
Regional ventilation heterogeneity index calculated from EIT ventilation waves; value ranges 0-1, where higher values represent less homogeneous ventilation.
Measured: Baseline, 30 minutes, and 60 minutes.
Change in Oxygenation Index (PaO₂/FiO₂ Ratio)
Ratio of arterial oxygen partial pressure to fraction of inspired oxygen, unit mmHg; range ≤ 300 mmHg inclusion criterion; higher values indicate better oxygen exchange.
Measured: Baseline, 30 minutes, and 60 minutes.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 May 2026
- Study start15 Jul 2026 (estimated)
- Primary completion30 Jul 2027 (estimated)
- Study completion30 Jul 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Acute Respiratory Failure (ARF)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- This study uses a prospective single-center crossover design. Each participant serves as his or her own control and receives two sequential antihypertensive interventions, nitroglycerin and nicardipine, in different study phases under stable mechanical ventilation settings. The order of drug administration is alternated between participants according to a computer-generated assignment list to minimize sequence effect. A 30-minute washout period or until hemodynamic parameters return to baseline is maintained between the two infusion periods. Continuous monitoring with electrical impedance tomography (EIT) allows within-subject comparison of ventilation-perfusion matching, dead space, and shunt fraction at defined time points (Baseline, 30 min, 60 min). This crossover model permits reduction of inter-individual variability and optimizes statistical power with a limited sample size.
- Masking
- None (open label)
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- First Affiliated Hospital of Wannan Medical College
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Qiancheng Xu, First Affiliated Hospital of Wannan Medical College
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07603037
- Sponsor's protocol ID
- 2026-ICU03
- Status last verified
- Jun 2026
- First submitted
- 18 May 2026
- Last updated
- 2 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided