An interventional study of Nitroglycerin and Nicardipine in Acute Respiratory Failure (ARF), Hypertension and Pulmonary Perfusion Imbalance, sponsored by First Affiliated Hospital of Wannan Medical College. Not yet recruiting at 1 site in China. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-02.
Sponsored by First Affiliated Hospital of Wannan Medical College · Not applicable, Interventional, and Basic science
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.
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.
6,114 studies on the registry are indexed under Hypertension; 912 are open to participants now.
This study's planned enrollment of 12 is below the median of 100 across 4,575 interventional studies indexed under Hypertension.
Browse Hypertension studies →First Affiliated Hospital of Wannan Medical College is the lead sponsor of 37 studies on the registry; 34 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Inclusion Criteria 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 obtained from the patient or the legally authorized representative.
Exclusion Criteria:
(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 or to nicardipine or nitroglycerin. Use of phosphodiesterase-5 inhibitors, such as sildenafil, tadalafil, or vardenafil, within the .
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.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Washout period
A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Drug: Nitroglycerin · Drug: Nicardipine
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.
Also known as: Glyceryl Trinitrate; Nitroglycerin Injection; Tridil®
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.
Also known as: Cardene; Nicardipine Hydrochloride
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.
Time frame: 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.
Time frame: 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.
Time frame: Baseline, 30 minutes, and 60 minutes.
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.
Time frame: 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.
Time frame: 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.
Time frame: Baseline, 30 minutes, and 60 minutes.
Plan to share: Undecided
No publications or documents are linked to this record.
Start is estimated for Jul 2026; primary completion for Jul 2027, 12 months later.
Of 1,403 non-industry interventional studies with no phase under Hypertension, half reached primary completion within 23 months of starting (the median), counting those still running; a quarter within 10 and three quarters within 41. This study's planned 12 months is below that.
Counting every sponsor, half of 1,498 studies reached it within 23 months; a quarter within 10 and three quarters within 41.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: Nitroglycerin · Nicardipine
First Affiliated Hospital of Wannan Medical College