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NCT Number: NCT05996120

Study on Optimal Temperature During Cardiopulmonary Bypass (THERMIC-4)

In order to perform heart surgery, a machine called cardiopulmonary bypass (CPB), or more commonly known as a heart-lung machine, is used to maintain the circulation of oxygenated blood needed by the rest of the body and its organs.

Historically, when a patient is connected to CPB, their body is cooled below the normal body temperature. This is known as hypothermia. This is because scientific studies have previously shown that reduced body temperature lowers metabolism and therefore offers more protection to the brain and other organs due to the reduced oxygen requirement. The evidence supporting this practice, however, has been challenged throughout the history of cardiac surgery, with studies supporting that normothermia, or normal body temperature, is a safe alternative. Despite this, the practice of hypothermia has persisted. Published data from a survey of 139 cardiac surgeons in the United Kingdom showed that 84% still routinely employ hypothermic CPB during surgery.

To assess whether normothermic or hypothermic CPB is safer, a clinical trial requiring a large sample size and high recruitment rates will be required. Therefore, the investigators aim to assess firstly the feasibility of trial recruitment and allocation adherence in this study. 100 adults across 10 different cardiac surgery centres in the United Kingdom will be recruited to a multicentre feasibility randomised controlled trial comparing normothermia (active comparator) against hypothermia (control comparator) during cardiopulmonary bypass in cardiac surgery. This study will also test the ability of the Cardiothoracic Interdisciplinary Research Network (CIRN), a trainee-led research collaborative, to collect pilot data on Major Adverse Cardiac and Cerebrovascular Events (MACCE) using a regulation-approved electronic application HealthBitⓇ. Participants will also be asked to complete quality of life surveys. The results of this study will subsequently inform a large, adequately powered randomised controlled trial for optimal temperature management during CPB.

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Key information

Conditions

Ischemic Heart Disease Body Temperature Changes Cardiovascular Diseases Heart Diseases Heart Valve Diseases Hypothermia Myocardial Ischemia Pathological Conditions, Signs and Symptoms Signs and Symptoms Surgery-Complications Valvular Heart Disease Vascular Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Glenfield Hospital, University Hospitals of Leicester NHS Trust, Leicester, Leicestershire, United Kingdom

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About this study

Primary Objective

To assess the feasibility of trial recruitment and delivery to target in the United Kingdom of a multicentre randomised controlled trial on normothermia versus hypothermia during cardiopulmonary bypass in adult cardiac surgery.

Secondary Objective

To assess the feasibility of conducting a multicentre randomized controlled trial (RCT) using a novel Good Clinical Practice (GCP) approved remote data capture as the primary trial database alongside analysis of routinely collected healthcare data.

To obtain pilot data, undertaken by the Cardiothoracic Interdisciplinary Research Network (CIRN), to inform a subsequent large, adequately powered RCT for optimal temperature management during CPB.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Participants may enter the trial if all of the following apply

  • Adult patients (≥ 18 years) scheduled for coronary artery bypass surgery and/or valve replacement/ repair, either in the elective or urgent setting.
  • European System for Cardiac Operative Risk Evaluation (EuroSCORE) II of 2 or higher.
  • Able to understand and communicate to provide informed consent.
  • Able to read and understand the English language.

Exclusion criteria

Participants may not enter the trial if any of the following apply:

  • Patients undergoing coronary artery bypass surgery in combination with other procedures including cardiac or vascular procedures that require deep hypothermic arrest.
  • Patients undergoing emergency or salvage surgery.
  • Patients undergoing off-pump cardiac surgery.
  • Patients who are participating in another interventional trial.
  • Unable to provide informed consent.

Treatment and study plan

Hypothermic cardiopulmonary bypass

Procedure

Mild hypothermia (between 32 - 35 °C) during cardiopulmonary bypass

Normothermic cardiopulmonary bypass

Procedure

Normothermia (active maintenance of temperature between 36.5 °C to 37.5°C; no active cooling below 36.5 °C) during cardiopulmonary bypass

Primary outcomes

  1. Total number of participants recruited over a 6 month period

    Time frame: 6 months

    The target recruitment rate is 1 participant per week per centre. The feasibility trial will be considered positive if 80% of target met, together with outcome 2.

  2. Adherence rate to allocation

    Time frame: 6 months

    The feasibility trial will be considered positive if 74%* of target adherence to trial allocation is met, together with outcome 1.

    *74% is derived from 80% of target adherence of 92% as per Warm Heart Study

Secondary outcomes

  1. Incidence of 6-week composite endpoint of Major Adverse Cardiac and Cerebrovascular Events (MACCE)

    Time frame: 6 weeks

    MACCE is defined as any post-operative death, stroke, new intra-aortic balloon pump insertion, new renal replacement therapy, re-operation and major bleeding in this feasibility trial.

  2. Incidence of deep sternal wound infection, with or without treatment

    Time frame: 6 weeks

    Deep sternal wound infection is defined with at least one of the following criteria:

    (I) an organism is isolated from culture of mediastinal tissue or fluid (II) evidence of mediastinitis seen intraoperatively (III) presence of chest pain, sternal instability, or fever (> 38 °C), and purulent drainage from the mediastinum or isolation of organism present in a blood culture or from the mediastinal area.

  3. Incidence of all adverse events

    Time frame: 6 weeks

    Composite of all reported adverse events. Examples of adverse events include: low cardiac output, suspected myocardial infarction, arrhythmias, infections, haemorrhage, and pulmonary embolus.

  4. Critical care length of stay

    Time frame: 6 weeks

    Number of days a participant is admitted in cardiac critical care unit

  5. Post-operative length of stay

    Time frame: 6 weeks

    Number of days a participant is an in-patient after index operation

  6. Frequency of post-discharge healthcare resource utilisation

    Time frame: 6 weeks

    Number of visits to general practitioner (GP) and/or hospital, either district general hospital or tertiary hospital, will be recorded via HealthBitⓇ.

  7. Quality of life post-operation: Medical Outcomes Study Short-Form 36 (SF-36)

    Time frame: 6 weeks

    Quality of life questionnaire (SF-36) will administered before surgery and at 6-week follow up

  8. Quality of life post-operation: European Quality of Life-5 Dimensions (EQ-5D)

    Time frame: 6 weeks

    Quality of life questionnaire (EQ-5D) will administered before surgery and at 6-week follow up

  9. Quality of life post-operation: World Health Organisation Disability Assessment Schedule (WHODAS)

    Time frame: 6 weeks

    Quality of life questionnaire (WHODAS) will administered before surgery and at 6-week follow up

  10. Clinical Frailty Scale (CFS) post-operation

    Time frame: 6 weeks

    Clinical Frailty Scale will be recorded before surgery and at 6-week follow up

Other outcomes

  1. Data completeness

    Time frame: 6 months

    Data recorded on HealthBitⓇ will be assessed for percentage of completion

  2. Attrition rate

    Time frame: 6 months

    For ascertainment of the primary outcome and for planning of future large-scale study

  3. User satisfaction of ResearchApp

    Time frame: 6 months

    Participants will be invited to complete optional survey on user satisfaction of ResearchApp

Study contacts

Contact information is provided by the study sponsor or research team.

Ann Cheng, MBChB, MSc

CONTACT

[email protected]

Gavin J Murphy, FRCS, MD, MBChB, BSc

CONTACT

[email protected]

0116 258 3054

Sponsors and collaborators

Lead sponsor

University of Leicester

Other

Collaborators

  • Hull University Teaching Hospitals NHS Trust
  • King's College Hospital NHS Trust
  • NHS National Waiting Times Centre Board
  • Oxford University Hospitals NHS Trust
  • Royal Brompton & Harefield NHS Foundation Trust
  • Sheffield Teaching Hospitals NHS Foundation Trust
  • University Hospital Plymouth NHS Trust
  • University Hospitals Bristol and Weston NHS Foundation Trust
  • University Hospitals, Leicester

Registry information

Official study title

Normothermic Versus Hypothermic Cardiopulmonary Bypass in Adult Cardiac Surgery: a Multicentre Feasibility Randomised Controlled Trial

Acronym: THERMIC-4

Important dates

Study start
2024
Primary completion
2025
Study completion
2026
First posted
Aug 16, 2023
Registry last updated
Apr 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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