High-dose Inhaled NO Therapy for the pREvenvention of NP After Cardiac Surgery Under CPB

High-dose Inhaled NO Therapy for the pREvention of nosoCOmial Pneumonia After Cardiac Surgery Under caRDiopulmonary Bypass

The primary aim of this single-center, prospective, randomized, controlled, study is to test the hypothesis that inhalation of NO 200 ppm prevents the development of nosocomial pneumonia in patients at risk after cardiac surgery under CPB. The study is interventional. Examination and treatment of patients is carried out in accordance with the approved standards of medical care for the relevant diseases. During the study, no experimental or unregistered (not approved for use) medical or diagnostic procedures in the territory of the Russian Federation will be carried out. The study includes patients admitted to the Cardiac Surgery Department of Cardiology Research Institute of Tomsk National Research Medical Center for elective surgery with CPB.

Study Overview

• Status: Completed
• Conditions: Nosocomial Pneumonia
• Intervention / Treatment: Drug: Sham treatment; Drug: 200-ppm NO

Detailed Description

NOSOCOMIAL PNEUMONIA AFTER CARDIAC SURGERY WITH CADIOPULMONARY BYPASS. Nosocomial pneumonia (NP) is one of the most common complications of cardiac surgery with cardiopulmonary bypass (CPB), its frequency according to various sources ranges from 2 to 10% . This complication is accompanied by higher mortality (0.7-4% in patients without pneumonia vs. 25.1-28.2% in patients with pneumonia) , prolonged hospital stay and increased economic costs. In the retrospective analysis of medical histories of patients operated on CPB for 2020, 2021 and 2022, 3 main risk factors for the development of NP in the postoperative period were identified: time of CPB ≥ 96 minutes, duration of mechanical ventilation ≥ 14 hours, and the presence of atrial fibrillation (AF) before surgery. STUDY NATURE In relation to medical procedures, this study is observational. The examination and treatment of patients will be carried out in accordance with the approved standards of medical care for the respective diseases. In this study, no experimental or unregistered (not approved for use) medical or diagnostic procedures on the territory of the Russian Federation will be carried out. STUDY TYPE Single-center, prospective, double-blind, randomized, controlled, parallel group study. STUDY OBJECTIVES PRIMARY OBJECTIVE OF THE STUDY To test the hypothesis that inhalation of NO 200 ppm prevents the development of NP in patients after cardiac surgery under CPB and has a positive effect on the structural and functional state of the external respiration.

SECONDARY OBJECTIVES OF THE STUDY

1. To test the hypothesis that inhalation of NO 200 ppm twice a day for 30 minutes for 5 days is safe for patients.
2. To test the hypothesis that prophylactic inhalation of NO 200 ppm twice a day for 30 minutes increases the duration of manifestation of nosocomial pneumonia (in case of its development) after cardiac surgery under CPB.
3. To test the hypothesis that prophylactic inhalation of NO 200 ppm twice a day for 30 minutes reduces the time of resolution of NP (in case of its development) after cardiac surgery under CPB.
4. To assess the differences in pulmonary function according to the 6-minute walk test (6MWT), spirometry and ergospirometry and their dynamics in the main and control groups.
5. To assess the morphological picture of the lungs and its dynamics according to lung ultrasound in the main and control groups.
6. To compare the level of acute phase reactants and their dynamics in the main and control groups.
7. To compare plasma levels of surfactant proteins SP-D and sRAGE and their dynamics in the main and control groups.

RATIONALE FOR RANDOMIZATION There is currently no convincing evidence of benefits or harms of NO inhalation as part of the prevention of NP after cardiac surgery with CPB. Thus, there is no reason to believe that randomization to study groups creates additional risks / benefits for patients. Nevertheless, regardless of the results of randomization, the decision on the possibility of prophylactic NO inhalation after cardiac surgery in each case will be made by a special medical commission consisting of a cardiac surgeon, anesthesiologist and cardiologist, immediately after the patient is enrolled in the study.

PATIENT RANDOMIZATION Patients eligible for this study will be randomized to the intervention group (NO group) and Control group in a 1: 1 ratio according to the randomization sequence generated by a computer program with random numbers by 80 people in each group. Patients will be randomized immediately after screening and signing the informed consent. Patients in both groups will not receive NO outside of the study protocol until discharged from the hospital. Patient randomization will be performed by a non-blinded NO delivery investigator who is not involved in the clinical management of the patient and the evaluation of treatment outcomes. Patients in the intervention group will receive inhaled NO therapy at a dose of 200 ppm 2 times a day for 5 days or until pneumonia is detected. In the control group, instead of inhaled NO therapy, patients will receive "Sham treatment": similar equipment and observation protocol during the intervention will be used as in the main group, but NO will not be added to the delivered gas mixture. BLINDING The gas supply systems will look the same for patients of both NO group and Control group. Patients, treating physicians, investigators and other professionals involved in the interpretation of the results will not be aware of the nature of the therapy until the end of the study. The investigating doctor who is responsible for the delivery and monitoring of the investigated gas will remain unblinded and will be responsible for blinding the gas delivery systems, monitoring and securing the delivery, and maintaining the randomization codes. Randomization codes will be sealed in sequentially numbered opaque envelopes. The sequential envelope numbers will serve as randomization numbers that will be recorded in patient's case report form (CRF) and used when necessary, for example, to treat complications. DOSAGE REGIMEN AND DURATION OF THERAPY When choosing the dose and timing of NO exposure, clinicians should be guided by 2 basic principles:

1. The dose of NO used and its exposure time must be safe for patients;
2. The dose of NO used and its exposure time must be sufficient to provide potential preventive effects. NO dosing guidelines for the prevention of pneumonia after cardiac surgery with CPB have not currently been developed, however, there is extensive data from experimental and clinical studies indicating the potential efficacy of a gas concentration of 200 ppm and an exposure time of 30 minutes, which will be implemented in the study. The safety of using NO for humans in doses of 160-200 ppm for 15-30 minutes 2 to 5 times a day has been demonstrated in a number of clinical studies, including in pregnant women and newborns. The absence of toxic effects of NO at a dose of 200 ppm has been proven on cultured skin fibroblasts, monocytes, macrophages and pulmonary epithelium. Most researchers emphasize the efficacy of intermittent multiple high-dose (160-200 ppm) NO therapy with an average duration of each inhalation for 30 minutes. NO DELIVERY After screening and signing the informed consent, patients will be randomized into one of the study groups: a control group with sham treatment and a study group, in which participants will receive inhalation of NO 200 ppm for 30 minutes twice a day for 5 days after extubation and transfer from the intensive care unit. NO delivery will be carried out using a semi-open circuit. The source of NO is the certified device, which synthesizes NO from atmospheric air using the method of plasma-chemical synthesis directly during therapy. The supply line for the studied gas is built into the supply line for the carrier gas (atmospheric air), the flow of which is provided by a compressor with a maximum flow of 18 l/min, which can be adjusted. The carrier gas flow and NO synthesis rate will be adjusted automatically so that the NO concentration is up to 200 ppm. Next, the gas mixture enters a 3-liter reservoir bag, from where the patient actively breathes it in. To separate the inspiratory and expiratory parts, inhalation and exhalation valves are provided in the circuit. To create an air tight seal with the circuit and patient's airways, correct sized air cushion anesthesia masks will be used. Gas is continuously sampled from the proximal end of the inspiratory part of the circuit to determine the concentration of NO and NO2 in it. MetHb levels during NO inhalation will be estimated continuously using a peripheral pulse oximeter with fractional saturation capability. During NO therapy, MetHb levels will be maintained at <5%. NO undergoes a chemical reaction to form NO2, which is an extremely toxic gas and can cause airway inflammation and lung tissue injury. This study regulates the control and maintenance of inhaled NO2 levels below 3 ppm. During NO therapy, vital functions and safety will be assessed immediately before the initiation of the session, after 15 minutes of NO and after its completion (Heart Rate, Blood Pressure, Respiratory Rate, Oxygen Saturation, MetHb). In addition, as part of the exploratory endpoint study, exhaled NO levels will be measured immediately before and after inhalation, 10 and 20 minutes after the end of inhalation. Patients from the control group will undergo sham-treatment, the algorithm of which is similar to inhalation in the main group, but NO will not be added to the gas mixture. SUMMARY OF KNOWN AND POTENTIAL RISKS AND BENEFITS OF NO-THERAPY NO undergoes a chemical reaction to form NO2. NO2 is an extremely toxic gas that can cause airway inflammation and lung tissue injury. Protocols in use today require that inhaled NO2 levels should be maintained below 3 ppm during NO therapy. The rate of NO2 formation depends on the concentration of NO and O2 in the inhaled gas-air mixture. This fact is important: sources with high concentrations of NO should be avoided; NO and inspiratory fraction of O2 (FiO2) should be used in the minimum clinically acceptable doses. During bench tests of the delivery system, NO2 concentration did not exceed 3 ppm when 200 ppm NO was supplied against the background of FiO2 = 100% (due to the use of a chemical sorbent), however, the minimum sufficient inspiratory fraction of O2 will be used when carrying out the study. NO oxidizes hemoglobin (Hb) (Fe+2) to form (MetHb) (Fe+3), which is unable to transport and release oxygen into the tissue and, as a result, can cause tissue hypoxia. Cyanosis is observed when MetHb levels approach 15-20%. The Institutional Review Board for this study recommended monitoring and maintaining MetHb levels below 5% of total hemoglobin concentration. MetHb levels will be continuously monitored using a peripheral pulse oximeter with the ability to measure fractional saturation (non-invasive pulse co-oximetry). If MetHb levels exceed 5% of the total Hb concentration, NO delivery will be stopped. An increase in MetHb levels > 30% as a critical incident in the study requires intravenous administration of methylene blue in 0.1-0.2 ml/kg of 1% solution (1-2 mg/kg). After half of the patients are recruited and preliminary statistical analysis is completed, a report on possible complications associated with the potentially negative effects of NO will be submitted. OBSERVATION PERIOD Monitoring of patients and registration of study data will be carried out until discharge from the hospital. The expected length of hospital stay after uncomplicated cardiac surgery will be approximately 2 weeks. If complications occur during the perioperative period, patients will be monitored until the event resolves/stabilizes. TERMINATION OR SUSPENSION OF THE CLINICAL STUDY The study will be terminated at the initiative of the study sponsor if, based on the results of an interim analysis or current monitoring, the risk of adverse outcomes in the NO-therapy group clinically or statistically significantly exceeds the similar risk in the control group..

Individual patient's participation in the study will be terminated prematurely in accordance with the following criteria:

1. Patient decision (withdrawal of informed consent).
2. Increased MetHb> 5% of hemoglobin level;
3. Increase in NO2 level> 3 ppm;
4. Intolerance to the proposed modality of therapy.

• Study Type: Interventional
• Enrollment (Actual): 160
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Russia
  • Tomsk, Russia
    • Cardiology Research Institute Tomsk national Research Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Cardiac surgery with CPB at current hospitalization.
2. Age > 18 years.
3. Signed informed consent

Exclusion Criteria:

1. Emergency surgery.
2. Acute coronary syndrome 30 days before surgery.
3. Surgery for active infective endocarditis requiring antibiotic therapy.
4. Diagnosed infectious process of another localization (surgical site infection (SSI), acute and chronic urinary tract infection (active), catheter-related bloodstream infection, peritonitis, etc.).
5. Taking antibacterial drugs for 14 days preceding surgery
6. Other complications of the postoperative period (pneumothorax requiring pleural drainage, perioperative myocardial infarction accompanied by pulmonary edema, shock of any etiology during the current hospitalization).
7. Potentially dialysis-dependent stage 2 and higher acute kidney injury (according to KDIGO) in the early postoperative period (the criteria for potentially dialysis-dependent acute kidney injury will include patients with stage 2 acute kidney injury and: oliguria against the background of normo-hypervolemia and resistance to loop diuretics and/ or oliguria against the background of conducting infusion therapy due to hypovolemia and resistance to loop diuretics).
8. Continued mechanical ventilation.
9. Delirium.
10. Presence of tracheostomy.
11. Patient's participation in another clinical trial at the time of screening or within the previous 3 months.
12. Concomitant pulmonary disease with the need for respiratory support before surgery.
13. History of malignancy or other irreversible diseases/conditions with a 6- month mortality rate >50%.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Control group; Oxygen-air mixture without NO after extubation within 5 days after surgery 2 times a day for 30 min	Drug: Sham treatment; Oxygen-air mixture without NO after extubation after surgery for 5 days 2 times a day for 30 min; Other Names: Oxygen-Air Mixture
Experimental: 200 ppm; NO will be supplemented at 200-ppm concentration after extubation within 5 days after surgery 2 times a day for 30 min	Drug: 200-ppm NO; NO will be supplemented at 200-ppm concentration after surgery for 5 days 2 times a day for 30 min; Other Names: Nitric Oxide

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of nosocomial pneumonia (percent)	The difference in the incidence of nosocomial pneumonia development (percent).	From the date of randomization until the date of discharge from hospital (from 2 to 4 weeks)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total leukocyte counts (10*9/L)	The difference in the levels of leukocytes (counts)	7 days from the date of randomization
Immature cell counts (percentage)	The difference between the levels of immature cells (counts) in the leukocyte formula	7 days from the date of randomization
C-reactive protein (CRP) level (mg/L)	The difference in the levels of C-reactive protein	7 days from the date of randomization
PCT (procalcitonin) test (ng/mL)	The difference in the levels of procalcitonin	7 days from the date of randomization
Presepsin levels (pg/mL)	The difference in the levels of presepsin	7 days from the date of randomization
Ferritin levels (ng/mL)	The difference in the levels of ferritin	7 days from the date of randomization
LDH (lactate dehydrogenase) levels (IU/L)	The difference in the levels of LDH	7 days from the date of randomization
Interleukin-6 (IL-6) levels (pg/mL)	The difference in the levels of IL-6	7 days from the date of randomization
Interleukin-8 (IL-8) levels (pg/mL)	The difference in the levels of IL-8	7 days from the date of randomization
Surfactant protein SP-D plasma levels (ng/mL)	The difference in the levels of SP-D	7 days from the date of randomization
sRAGE levels (pg/mL)	The difference in the levels of sRAGE	7 days from the date of randomization
endothelin-1 levels (pg/mL)	The difference in the levels of endothelin-1	7 days from the date of randomization
Asymmetric dimethylarginine (ADMA) levels (ng/mL)	The difference in the levels of ADMA	7 days from the date of randomization
Vascular endothelial growth factor A (VEGF-A) levels (pg/mL)	The difference in the levels of VEGF-A	7 days from the date of randomization
Angiopoietin-1 levels (ng/mL)	The difference in the levels of angiopoietin-1	7 days from the date of randomization
Angiopoietin-2 levels (ng/mL)	The difference in the levels of angiopoietin-2	7 days from the date of randomization
S/F index (ratio)	The difference in S/F index	7 days from the date of randomization
Incidence of adverse lung ultrasound findings (percentage)	Adverse lung ultrasound findings are: increase in the volume of pleural effusion, appearance of consolidation, increase in the severity of interstitial involvement (increase in the number of B-lines)	7 days from the date of randomization
Six-minute walk test (6MWT) distance (meters)	Six-minute walk test (6MWT) distance (meters) is assessed.	10 days from the date of randomization
Lung vital capacity (L)	Lung vital capacity is assessed in liters (L)	7 days from the date of randomization
Forced vital capacity (L)	Forced vital capacity is assessed in liters (L)	7 days from the date of randomization
Forced expiratory volume (L/s)	Forced expiratory volume is assessed in liters per second (L/s)	7 days from the date of randomization
Peak expiratory flow (L/s)	Peak expiratory flow is assessed in liters per second (L/s)	7 days from the date of randomization
VE-minute ventilation (L/min)	VE-minute ventilation is assessed in liters per minute	10 days from the date of randomization
VT-tidal volume (L)	VT-tidal volume is assessed in liters	10 days from the date of randomization
VE/VO2 - ventilatory equivalents for oxygen (ratio)	VE/VO2 is assessed as ratio of VE to VO2	10 days from the date of randomization
VE/VСO2 - ventilatory equivalent for carbon dioxide	VE/VСO2 is assessed as ratio of VE to VCO2	10 days from the date of randomization
PetO2 - partial pressure of oxygen in exhaled air (mm Hg)	PetO2 is assessed in mm Hg	10 days from the date of randomization
PetCO2 - partial pressure of carbon dioxide in exhaled air (mmHg)	PetCO2 is assessed in mm Hg	10 days from the date of randomization
Exhaled NO levels (ppm)	The difference in the levels of exhaled NO before the start of the inhaled NO inhalations, upon its completion, 10 and 20 minutes after its completion.	Every day from the date of randomization until day 7
Systolic blood pressure (SBP) levels (mmHg)	The difference in the levels of SBP	Every day from the date of randomization until day 7
Diastolic blood pressure (DBP) levels (mmHg)	The difference in the levels of DBP	Every day from the date of randomization until day 7
Heart rate (HR) (bpm)	The difference in HR is assessed in beats per minute	Every day from the date of randomization until day 7
Respiratory rate (RR) (brpm)	The difference in RR is assessed in breaths per minute	Every day from the date of randomization until day 7
Saturation of peripheral oxygen (SpO2) levels (percentage)	The difference in SpO2 levels	Every day from the date of randomization until day 7

Collaborators and Investigators

• Sponsor: Tomsk National Research Medical Center of the Russian Academy of Sciences
• Investigators: Principal Investigator: Nikolay O. Kamenshchikov, Cardiology Research Institute, Tomsk National Research Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): February 20, 2024
• Primary Completion (Actual): May 20, 2025
• Study Completion (Actual): October 1, 2025

Study Registration Dates

• First Submitted: February 7, 2024
• First Submitted That Met QC Criteria: February 7, 2024
• First Posted (Actual): February 15, 2024

Study Record Updates

• Last Update Posted (Estimated): December 9, 2025
• Last Update Submitted That Met QC Criteria: December 8, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Disease Attributes; Respiratory Tract Infections; Infections; Respiratory Tract Diseases; Lung Diseases; Pneumonia; Cross Infection; Iatrogenic Disease; Pathological Conditions, Signs and Symptoms; Healthcare-Associated Pneumonia; Organic Chemicals; Inorganic Chemicals; Nitrogen Compounds; Oxides; Oxygen Compounds; Free Radicals; Nitrogen Oxides; Reactive Nitrogen Species; Nitric Oxide
• Other Study ID Numbers: RECORD

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Deidentified individual participant data (text, tables, figures, and appendices), underlying the results of the trial, will be shared with researchers to achieve the aims in the approved proposal.
• IPD Sharing Time Frame: Proposals may be submitted up to 36 months following publication of the results of the trial. After 36 months, the data will be available in the Center's data ware house but without investigator support other than deposited metadata.
• IPD Sharing Access Criteria: Information regarding submitting proposals and accessing data may be requested from the principal investigator by e-mail.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No