Heating-Cooling Units (HCUs) are the unsung heroes of cardiac surgery and oncology treatments, ensuring precise temperature control during life-critical procedures. Whether it’s cooling the heart during open-heart surgery or maintaining hyperthermia for cancer treatment, HCUs play a pivotal role in modern medicine. But here’s the shocking reality: These essential machines have also been linked to deadly bacterial outbreaks, including Mycobacterium chimaera and Legionella, putting thousands of patients at risk. Contaminated water sources, improper maintenance, and aerosolized bacteria have made HCUs a double-edged sword—saving lives while potentially endangering them.
- What You’ll Discover in This Guide:
- ✅ How HCUs precisely regulate body temperature in surgery & oncology
- ✅ Why bacterial contamination is a silent threat in operating rooms
- ✅ Step-by-step safety protocols to prevent infection risks
- ✅ Top HCU manufacturers & cutting-edge innovations for safer use
Mechanism & Working Principle of HCUs
- How Heating-Cooling Units (HCUs) Work: The Science Behind Temperature Regulation in Surgery
The Role of HCUs in Cardiac Surgery & Oncology
Heating-Cooling Units (HCUs) are specialized devices that regulate body temperature during critical medical procedures, ensuring patient safety during prolonged surgeries. They function by circulating temperature-controlled water through external heat exchangers, which then transfer heat or cold to the patient’s blood, organs, or body surface.
In cardiac surgery, HCUs help induce therapeutic hypothermia to protect the heart and brain during cardiopulmonary bypass (CPB). In oncology, they are used in Hyperthermic Intraperitoneal Chemotherapy (HIPEC) to increase the effectiveness of certain cancer treatments.
Key Components of a Heating-Cooling Unit (HCU)
1️⃣ Water Reservoir & Pump System
Stores and circulates temperature-controlled water.
Pumps regulate flow to different circuits (patient blanket, CPB machine, cardioplegia).
2️⃣ Heat Exchanger Coils
Transfers heat between water and blood in an external circuit.
Used to warm or cool blood before it re-enters the body.
3️⃣ Temperature Control System
Advanced digital controls maintain precise target temperatures.
Allows independent control of multiple circuits.
4️⃣ Water Pathways & Connections
Primary water circuit: Cools or warms blood via the heart-lung machine.
Secondary circuit: Used for patient warming blankets or organ cooling.
Cardioplegia circuit: Maintains myocardial protection during surgery.
Step-by-Step: How an HCU Regulates Temperature
1️⃣ Cold or warm water is circulated from the HCU to heat exchangers.
2️⃣ Blood or cardioplegia solution passes through the heat exchanger, where temperature is adjusted.
3️⃣ The temperature-controlled fluid returns to the patient via the CPB circuit, cardioplegia system, or warming blanket.
4️⃣ Continuous monitoring ensures precise temperature regulation, preventing hypothermia or overheating.
🚑 In short, HCUs act as external temperature regulators, preventing life-threatening temperature fluctuations during surgery!
Why Are Heating-Cooling Units (HCUs) Used? Indications & Clinical Applications
Heating-Cooling Units (HCUs) are indispensable in cardiac surgery and certain oncology treatments, allowing precise temperature control to protect organs, optimize circulation, and enhance treatment efficacy. Below, we break down the key indications and specific use cases of HCUs in modern medicine.
Cardiac Surgery: Temperature Control During Cardiopulmonary Bypass (CPB)
During open-heart surgery, controlling patient temperature is crucial to prevent ischemic injury and optimize metabolic demands. HCUs work with the heart-lung machine (CPB circuit) to regulate blood temperature throughout the procedure.
🔹 Key Applications in Cardiac Surgery
✅ Inducing hypothermia (28–32°C) to protect the brain & heart during CPB
✅ Gradual rewarming after bypass to avoid reperfusion injury
✅ Cooling myocardial tissue with cardioplegia solution for heart protection
✅ Maintaining normothermia (36–37°C) in certain procedures to optimize metabolism
Surgeries That Require HCUs:
- Coronary Artery Bypass Grafting (CABG)
- Valve Replacement & Repair
- Congenital Heart Surgery (e.g., Tetralogy of Fallot, HLHS)
- Aortic Aneurysm & Dissection Repairs
- Heart Transplantation
Hyperthermic Intraperitoneal Chemotherapy (HIPEC) in Cancer Treatment
HCUs are also used in oncology, particularly for Hyperthermic Intraperitoneal Chemotherapy (HIPEC)—a specialized treatment for abdominal cancers where heated chemotherapy is circulated directly in the peritoneal cavity.
🔹 How HCUs Enhance HIPEC Therapy:
✅ Maintains the chemotherapy fluid at 40–42°C to improve drug penetration
✅ Increases cancer cell sensitivity to chemotherapy
✅ Minimizes systemic toxicity by limiting drug exposure to the bloodstream
Cancers Treated with HIPEC & HCUs:
- Peritoneal Carcinomatosis
- Appendiceal & Colorectal Cancers
- Ovarian Cancer
- Mesothelioma
Other Medical Applications of HCUs
🔹 ECMO (Extracorporeal Membrane Oxygenation)
HCUs are used in extracorporeal life support (ECLS) to regulate blood temperature during prolonged heart-lung support.
🔹 Therapeutic Hypothermia in Neurocritical Care
After cardiac arrest or traumatic brain injury, HCUs are used to induce targeted temperature management (TTM) to reduce neurological damage.
🔹 Limb Perfusion for Isolated Chemotherapy Treatments
Used in Isolated Limb Perfusion (ILP) for treating sarcomas or melanoma by delivering heated chemotherapy to a specific limb while protecting systemic circulation.
Why Temperature Control Matters in These Cases
🔹 Hypothermia (28–32°C): Protects organs from ischemic damage during CPB & ECMO
🔹 Normothermia (36–37°C): Maintains normal metabolism in general surgeries
🔹 Hyperthermia (40–42°C): Enhances chemotherapy effectiveness in HIPEC & limb perfusion
🔥 Key Takeaway:
HCUs are not just another piece of OR equipment—they are critical life-saving devices used to fine-tune body temperature, optimize surgery outcomes, and improve survival in complex medical procedures.
4. Common Use Cases of Heating-Cooling Units (HCUs)
- Cardiac Surgery Applications:
- Hypothermia & rewarming during cardiopulmonary bypass (CPB)
- Cardioplegia cooling & myocardial protection
- Oncology Applications:
- Hyperthermia treatment in certain cancers (HIPEC – Hyperthermic Intraperitoneal Chemotherapy)
- Therapeutic temperature control for tumor sensitivity to treatment
- Other Uses: ECMO, neonatal hypothermia therapy
Hidden Dangers of Heating-Cooling Units (HCUs): Infection Risks & Potential Hazards
While Heating-Cooling Units (HCUs) are essential for life-saving procedures, they also pose serious risks if not properly maintained. Contaminated water reservoirs, aerosolized bacteria, and improper disinfection have been linked to severe infections and even fatal complications in patients.
🚨 Key Risks Associated with HCUs:
✅ Bacterial contamination (Mycobacterium chimaera, Legionella, Pseudomonas, etc.)
✅ Biofilm formation in water circuits, leading to persistent infection sources
✅ Aerosolization of pathogens, spreading bacteria into the OR environment
✅ Thermal injury (overheating or hypothermia) if temperature regulation fails
✅ Cross-contamination due to improper handling of water circuits
Let’s break these down in detail.
Deadly Bacteria Found in Heating-Cooling Units (HCUs)
Several bacterial species have been linked to infections originating from contaminated HCUs, with Mycobacterium chimaera being the most notorious.
🔬 Most Common Bacterial Contaminants in HCUs:
| Bacteria | Infection Risk | Source of Contamination |
|---|---|---|
| Mycobacterium chimaera | Endocarditis, sepsis, multi-organ failure | Contaminated water in HCU reservoirs |
| Legionella pneumophila | Severe pneumonia (Legionnaires’ disease) | Aerosolized bacteria from warm water |
| Pseudomonas aeruginosa | Bloodstream infections, ventilator-associated pneumonia | Biofilm in water pathways |
| Non-tuberculous mycobacteria (NTM) | Chronic infections, lung complications | Poorly disinfected internal circuits |
| Staphylococcus aureus | Surgical site infections, bacteremia | Cross-contamination from handling |
📌 Case Reports: Mycobacterium chimaera outbreaks have been linked to HCUs used in cardiac surgeries, with multiple cases reported worldwide, leading to severe post-op infections.
How Do HCUs Spread Infections?
Even though HCUs do not come into direct contact with the patient’s blood, they can still cause life-threatening infections through indirect contamination mechanisms:
🔹 Aerosolization of Bacteria:
- Warm water in the HCU can generate infected aerosols, spreading bacteria into the operating room air.
- These particles may settle on surgical instruments, enter the CPB circuit, or be inhaled by the patient.
🔹 Biofilm Formation in Water Pathways:
- Bacteria attach to internal surfaces of the water reservoirs, forming biofilms resistant to disinfection.
- Over time, these biofilms continuously release bacteria into the circulating water.
🔹 Cross-Contamination via Water Handling:
- Improper filling, draining, or refilling of HCUs with tap water or non-sterile solutions introduces pathogens into the system.
📌 Key Fact: Studies have shown that Mycobacterium chimaera can survive in HCUs for months to years, even after routine cleaning!
Other Hazards of Heating-Cooling Units (HCUs)
💀 Thermal Injury to Patients:
- Overheating (>42°C) can cause burns or hemolysis in blood products.
- Excessive cooling (<28°C) can lead to cardiac arrhythmias and impaired coagulation.
⚠️ Device Malfunction & Temperature Fluctuations:
- A failing thermostat or sensor can lead to sudden temperature drops or spikes, causing organ damage or metabolic derangements.
🚨 Risk of Water Leaks in the OR:
- Water leakage from HCUs can contaminate sterile surgical fields, leading to post-op infections.
How to Prevent Infections & Maintain Safe HCUs
Best Practices for HCU Infection Prevention
✅ Use only sterile, deionized, or manufacturer-recommended water
✅ Perform daily and weekly disinfection per manufacturer guidelines
✅ Regularly replace water filters and tubing
✅ Avoid placing HCUs inside the sterile field to minimize aerosol spread
✅ Monitor for biofilm formation and flush the system regularly
Standard Operating Procedures (SOPs) for Safe Use & Maintenance of Heating-Cooling Units (HCUs)
To ensure patient safety and infection control, strict protocols must be followed for the handling, maintenance, and disinfection of Heating-Cooling Units (HCUs). Below is a step-by-step SOP guide designed for perfusionists, biomedical engineers, and OR staff to minimize risks and maintain optimal performance of HCUs.
1️⃣ Setup & Daily Operation Protocol
🔹 Pre-Use Inspection Checklist:
✔️ Check the water levels in the HCU reservoir.
✔️ Ensure the correct type of water (sterile or manufacturer-recommended) is used.
✔️ Inspect for visible biofilm, sediment, or discoloration in tubing and reservoirs.
✔️ Verify temperature settings and calibration before starting circulation.
✔️ Confirm that the HCU is placed away from the sterile surgical field to prevent aerosol contamination.
🔹 Daily Start-Up Procedure:
1️⃣ Turn on the HCU and allow self-diagnostic checks to complete.
2️⃣ Set target temperatures for patient circuits, cardioplegia, and blood flow regulation.
3️⃣ Confirm all connections are secure and there are no leaks in the system.
4️⃣ Monitor water flow and temperature consistency during surgery.
2️⃣ Infection Prevention & Water Quality Maintenance
🚨 Critical Water Management Protocols
🔹 Water Source Guidelines:
✅ ONLY use sterile, deionized, or manufacturer-approved water to prevent bacterial growth.
✅ Do NOT use tap water—it contains minerals and potential contaminants that promote biofilm formation.
✅ Change water at least once per case or per hospital infection control policies.
🔹 Filtration & Water Treatment:
✔️ Use 0.2-micron bacterial filters to prevent microbial contamination.
✔️ Replace filters as per manufacturer guidelines or sooner if clogged.
✔️ Consider UV light sterilization systems in HCUs for added protection.
3️⃣ Disinfection & Preventive Maintenance Protocol
Daily Disinfection Routine
✔️ Drain and refill reservoirs with fresh sterile water after each procedure.
✔️ Wipe external surfaces with hospital-grade disinfectant.
✔️ Inspect tubing for discoloration or residue buildup.
Weekly Deep Cleaning Protocol
🔹 Flush the system with approved chemical disinfectants (e.g., hydrogen peroxide, peracetic acid, or chlorine-based solutions).
🔹 Allow the disinfectant to circulate for manufacturer-recommended contact time.
🔹 Rinse thoroughly with sterile, deionized water to remove chemical residues.
🔹 Perform a bacterial culture test periodically to check for contamination.
📌 Common Disinfectants for HCUs:
| Disinfectant Type | Effectiveness | Recommended Use |
|---|---|---|
| Hydrogen Peroxide (H₂O₂) | Kills Mycobacterium & biofilms | Weekly deep cleaning |
| Peracetic Acid | Strong against Legionella & NTM | Monthly sterilization |
| Sodium Hypochlorite (Bleach) | General bacterial disinfection | Routine cleaning |
| UV Light Sterilization | Prevents biofilm formation | Continuous treatment |
4️⃣ Regular Maintenance & Troubleshooting
🔹 Routine HCU Performance Checks:
✔️ Test temperature accuracy using an external thermometer.
✔️ Inspect all tubing and connectors for cracks or leaks.
✔️ Monitor pump function and water flow rate to detect obstructions.
✔️ Check for unusual noise or vibrations, which may indicate pump issues.
🔹 Troubleshooting Common HCU Issues:
| Issue | Possible Cause | Solution |
|---|---|---|
| Water discoloration or biofilm | Contaminated water or poor disinfection | Perform deep cleaning & flush system |
| Fluctuating temperature control | Sensor malfunction or air bubbles | Check calibration, remove air bubbles |
| Slow or obstructed water flow | Clogged filter or tubing blockage | Replace filters, inspect tubing |
| Alarming bacterial culture results | Inadequate disinfection | Increase frequency of sterilization |
5️⃣ Safety Best Practices for Perfusionists & OR Staff
✅ Keep HCUs positioned OUTSIDE the sterile field to prevent bacterial spread.
✅ Never leave stagnant water in the system—drain and refill after each case.
✅ Label and track maintenance records to ensure compliance with hospital protocols.
✅ Regularly test water for bacterial contamination to prevent outbreaks.
✅ Educate surgical teams on the risks of aerosolized bacteria .
Infections & Bacteria Associated with Heating-Cooling Units (HCUs)
Heating-Cooling Units (HCUs) have been directly linked to life-threatening infections due to bacterial contamination, biofilm formation, and aerosolization of pathogens into the operating room (OR). Despite not coming into direct contact with the patient’s blood, contaminated water inside HCUs can release harmful bacteria into the air, posing severe risks in cardiac surgeries and oncological procedures.
🔬 Deadly Bacteria Found in Heating-Cooling Units (HCUs)
Several bacterial species have been identified in contaminated HCUs, with Mycobacterium chimaera being the most notorious. These bacteria thrive in warm, stagnant water inside the unit’s reservoir and tubing, forming biofilms that resist standard cleaning protocols.
🦠 Most Common Bacterial Contaminants in HCUs
| Bacteria | Infection Type & Risks | Source of Contamination |
|---|---|---|
| Mycobacterium chimaera | Endocarditis, sepsis, multi-organ failure | Contaminated water, aerosolization |
| Legionella pneumophila | Severe pneumonia (Legionnaires’ disease) | Warm water mist, airborne exposure |
| Pseudomonas aeruginosa | Bloodstream infections, ventilator pneumonia | Biofilm in tubing, contaminated surfaces |
| Staphylococcus aureus | Surgical site infections, bacteremia | Cross-contamination in OR environment |
| Non-tuberculous mycobacteria (NTM) | Chronic lung infections, granulomas | Poorly disinfected water circuits |
📌 Key Fact: Mycobacterium chimaera infections linked to HCUs have been reported in multiple hospitals globally, leading to FDA warnings, lawsuits, and strict disinfection protocols.
🔴 How HCUs Spread Bacteria & Cause Infections
Even though HCUs do not come into direct contact with blood, they pose a serious infection risk through indirect contamination mechanisms:
1️⃣ Aerosolization of Bacteria
- Warm water inside the HCU generates a mist that can carry bacteria into the OR air.
- These airborne bacteria settle on surgical instruments, open wounds, or enter the cardiopulmonary bypass (CPB) circuit, leading to severe bloodstream infections.
2️⃣ Biofilm Formation in Water Reservoirs
- Bacteria inside HCUs attach to tubing walls and form biofilms, making them resistant to standard cleaning.
- These biofilms continuously release bacteria into circulating water, increasing contamination risks.
3️⃣ Cross-Contamination from Poor Handling
- Using tap water instead of sterile or deionized water introduces harmful pathogens into the system.
- Improper water changes and failure to disinfect filters allow bacterial colonies to multiply.
📌 Case Study: Infections linked to LivaNova 3T HCUs led to multiple patient deaths, prompting FDA warnings and recalls due to Mycobacterium chimaera contamination.
🚨 Risks & Complications of HCU-Related Infections
🔴 Endocarditis & Bloodstream Infections – Mycobacterium chimaera and Pseudomonas can cause fatal endocarditis in post-op cardiac surgery patients.
🫁 Severe Pneumonia & Lung Infections – Legionella and NTM infections may lead to chronic lung disease and multi-organ failure.
⚠️ Surgical Site Infections (SSIs) – Staphylococcus and Pseudomonas can cause deep wound infections, increasing post-op mortality.
🛑 Preventing HCU-Associated Infections: Best Practices
✅ Use only sterile, deionized, or manufacturer-approved water.
✅ Perform daily, weekly, and monthly deep cleaning with effective disinfectants.
✅ Avoid placing HCUs near the sterile surgical field to minimize aerosol spread.
✅ Use 0.2-micron bacterial filters to prevent contamination of water circuits.
✅ Monitor for biofilm formation and replace tubing at recommended intervals.
Leading Manufacturers of Heating-Cooling Units (HCUs) & Industry Innovations
Several medical device manufacturers produce Heating-Cooling Units (HCUs) for use in cardiac surgery and oncology. These companies focus on precision temperature control, infection prevention, and compliance with regulatory standards (FDA, CE, ISO).
🔹 Top Global Manufacturers of HCUs
| Manufacturer | Model/Series | Key Features | Region |
|---|---|---|---|
| LivaNova (Sorin Group) | 3T Heater-Cooler System | Dual-circuit cooling, FDA warnings for infection risks | Europe, USA |
| Terumo Corporation | HX2 Heater-Cooler | Integrated with CPB circuits, precise temperature control | Japan, Global |
| Maquet (Getinge Group) | HCU 40 / HCU 30 | High-flow water circuits, advanced disinfection modes | Europe, Global |
| Stockert (Sorin Group) | S3 Heater-Cooler | Silent operation, microprocessor-based regulation | Germany |
| Wandfluh (ECM Group) | W-MHCU | Customizable settings, durable stainless steel design | Switzerland |
📌 Regulatory Considerations:
- LivaNova 3T Heater-Cooler has been linked to Mycobacterium chimaera outbreaks, prompting FDA safety alerts and strict disinfection protocols.
- Newer models from Terumo and Maquet focus on reducing aerosolization risk by modifying water circulation designs.
🔹 Industry Innovations in HCU Technology
✅ Next-Gen UV Sterilization:
- Some manufacturers are integrating UV light chambers inside HCUs to kill bacteria before aerosolization occurs.
- Reduces the need for frequent deep chemical cleaning.
✅ Closed-Loop Water Circuits:
- Newer HCUs are moving towards closed-loop designs to prevent airborne bacterial spread.
- This innovation is expected to reduce the risk of Mycobacterium chimaera infections.
✅ Smart Sensor-Based Disinfection Alerts:
- AI-based self-monitoring HCUs can detect biofilm formation and automatically trigger disinfection cycles.
- Future models may include real-time bacterial load monitoring.
Standard Operating Procedures (SOPs) for Disinfection & Preventive Maintenance of Heating-Cooling Units (HCUs)
To minimize infection risks and ensure optimal performance, Heating-Cooling Units (HCUs) require strict disinfection protocols and preventive maintenance schedules. Contaminated HCUs have been linked to life-threatening bacterial outbreaks, making regular cleaning, water quality management, and proper handling mandatory in cardiac surgery and oncology settings.
🔹 1️⃣ Daily Disinfection & Water Change Protocol
✔️ Step-by-Step Daily Cleaning Routine
1️⃣ Drain the HCU water reservoir completely after each case.
2️⃣ Refill with fresh sterile, deionized, or manufacturer-approved water. Never use tap water!
3️⃣ Run the system for 5–10 minutes to flush any residual contaminants.
4️⃣ Check for discoloration, residue, or visible biofilm in tubing and connectors.
5️⃣ Disinfect external surfaces using a hospital-grade antiseptic wipe.
6️⃣ Ensure proper ventilation to minimize airborne bacterial spread.
📌 Why? Stagnant water promotes biofilm growth, which harbors Mycobacterium chimaera, Pseudomonas aeruginosa, and Legionella pneumophila.
🔹 2️⃣ Weekly Deep Disinfection Protocol
🔬 Effective Disinfectants for HCUs
| Disinfectant | Action | Recommended Use |
|---|---|---|
| Hydrogen Peroxide (H₂O₂) | Destroys biofilm & Mycobacterium | Weekly deep cleaning |
| Peracetic Acid | Effective against Legionella & NTM | Monthly sterilization |
| Sodium Hypochlorite (Bleach) | Kills bacteria but requires thorough rinsing | Routine disinfection |
| UV Light Sterilization | Prevents biofilm formation | Continuous treatment |
📌 Weekly Cleaning Procedure:
1️⃣ Drain existing water & rinse reservoir with sterile water.
2️⃣ Fill with an approved disinfectant solution (H₂O₂ or peracetic acid) & circulate for 30-60 minutes.
3️⃣ Drain & rinse multiple times with sterile, deionized water to remove chemical residues.
4️⃣ Inspect & replace water filters if necessary.
5️⃣ Run a bacterial culture test periodically to confirm sterilization.
📌 Key Fact: HCUs have been recall-listed by the FDA due to Mycobacterium chimaera infections caused by improper disinfection!
🔹 3️⃣ Monthly Preventive Maintenance Protocol
🔧 Critical HCU Maintenance Checks:
✔️ Test temperature accuracy using an external thermometer.
✔️ Inspect water flow & pump efficiency to detect blockages.
✔️ Check tubing for cracks, leaks, or discoloration indicating biofilm presence.
✔️ Replace bacterial filters & worn-out components as per manufacturer guidelines.
✔️ Log disinfection & maintenance records for compliance.
📌 Why? Ignoring preventive maintenance can lead to bacterial outbreaks, unexpected failures, and life-threatening patient infections.
🔹 4️⃣ Advanced Infection Control Measures
✅ Closed-loop HCU models – Newer HCUs feature sealed water circuits to eliminate aerosolization risk.
✅ HEPA Filtration & UV Light Systems – Hospitals are adopting high-efficiency particulate air (HEPA) filters & UV sterilization chambers to reduce bacterial spread.
✅ Automated Self-Cleaning HCUs – AI-driven self-disinfecting systems may soon replace traditional manual cleaning.
Safety Checklist of Heating-Cooling Units (HCUs)
- Pre-Operative Safety Checklist
- Connection of Water Lines (Pressure & flow settings)
- Outlet management for:
- Patient blanket/warming device
- CPB circuit cooling
- Cardioplegia cooling & rewarming
- Real-time monitoring of HCU performance
10. Recent FDA & CDC Guidelines for HCU Safety
- Regulations for minimizing bacterial contamination
- Recall history of certain HCU models
- Hospital infection control strategies
11. Future of Heating-Cooling Units: Innovations & Safety Enhancements
- Advanced filtration & self-cleaning systems
- AI-based temperature control for improved efficiency
- Alternatives to water-based HCUs: Air-based & thermoelectric devices.
10 FAQs about Heating-Cooling Units (HCUs) in Cardiac Surgery & Oncology,
1️⃣ What is a Heating-Cooling Unit (HCU), and why is it used in cardiac surgery?
🔹 Answer: A Heating-Cooling Unit (HCU) is a medical device used to regulate patient body temperature during cardiac surgery. It circulates temperature-controlled water to a heat exchanger, which then warms or cools the patient’s blood via the heart-lung machine. This helps maintain optimal organ function during procedures like cardiopulmonary bypass (CPB), deep hypothermic circulatory arrest (DHCA), and myocardial protection.
2️⃣ How are Heating-Cooling Units (HCUs) used in oncology treatments?
🔹 Answer: In oncology, HCUs assist in hyperthermic intraperitoneal chemotherapy (HIPEC) and hyperthermia therapy.
- HIPEC: After surgical removal of tumors, heated chemotherapy drugs are circulated using an HCU to target abdominal cancers like mesothelioma and peritoneal carcinomatosis.
- Hyperthermia Therapy: HCUs help deliver controlled heat to tumors, making radiation and chemotherapy more effective while reducing damage to healthy tissue.
3️⃣ What are the risks of infection associated with HCUs?
🔹 Answer: HCUs can become contaminated with bacteria and biofilm if not properly disinfected.
- The biggest threat is Mycobacterium chimaera, a slow-growing bacteria that can cause life-threatening infections in post-surgical patients.
- Other pathogens include Legionella pneumophila, Pseudomonas aeruginosa, and non-tuberculous mycobacteria (NTM).
- Infection risks increase when contaminated aerosols from HCUs enter the operating room air supply.
4️⃣ How do hospitals prevent bacterial contamination in HCUs?
🔹 Answer: Hospitals follow strict disinfection and maintenance protocols, including:
✅ Using sterile or deionized water instead of tap water.
✅ Daily, weekly, and monthly cleaning cycles with hospital-grade disinfectants.
✅ HEPA filtration and UV sterilization to reduce airborne bacteria.
✅ Closed-loop HCU systems to prevent water exposure to air.
5️⃣ Can HCUs affect patient outcomes in cardiac surgery?
🔹 Answer: Yes. Precise temperature control is crucial for:
✅ Reducing metabolic demand during open-heart surgery.
✅ Preventing hypothermia or hyperthermia, which can cause complications.
✅ Enhancing myocardial protection with controlled cardioplegia delivery.
HCUs directly impact patient recovery, and malfunctioning units can lead to infection, temperature instability, and surgical complications.
6️⃣ What regulatory actions have been taken against HCUs due to infection risks?
🔹 Answer:
- The FDA and CDC issued warnings about the Stockert 3T HCU due to outbreaks of Mycobacterium chimaera.
- Some HCUs have been recalled or updated with improved filtration and ventilation systems.
- Hospitals are now required to follow strict cleaning, water quality testing, and maintenance schedules to reduce infection risks.
7️⃣ What are the signs and symptoms of an HCU-related infection?
🔹 Answer: Patients exposed to contaminated HCUs may develop delayed infections (months or years after surgery). Symptoms include:
⚠️ Unexplained fever lasting weeks or months.
⚠️ Fatigue, night sweats, and weight loss.
⚠️ Persistent cough, difficulty breathing, or wound infections.
⚠️ Endocarditis or bloodstream infections.
Patients undergoing immunosuppressive oncology treatments are also high-risk for HCU-related infections.
8️⃣ What disinfectants are used to clean HCUs?
🔹 Answer: Hospitals use medical-grade disinfectants such as:
✅ Hydrogen Peroxide (H₂O₂): Kills biofilm and Mycobacterium chimaera.
✅ Peracetic Acid: Strong antimicrobial, used for deep sterilization.
✅ Sodium Hypochlorite (Bleach): Effective but must be thoroughly rinsed.
✅ UV Light Sterilization: Prevents bacterial growth inside water circuits.
9️⃣ What are the key differences between open-loop and closed-loop HCUs?
🔹 Answer:
- Open-loop HCUs: Circulate water that is exposed to air, increasing infection risks.
- Closed-loop HCUs: Use sealed water systems to prevent bacterial aerosolization, making them safer and reducing contamination risks.
Most modern hospitals are switching to closed-loop HCUs to minimize bacterial exposure in cardiac and oncology patients.
🔟 Who are the leading manufacturers of HCUs worldwide?
🔹 Answer: Several medical device companies manufacture HCUs, including:
🏥 LivaNova (Stockert 3T) – Previously linked to Mycobacterium chimaera outbreaks.
🏥 Terumo – Produces advanced temperature management systems.
🏥 Maquet/Getinge – Specializes in closed-loop, low-infection-risk HCUs.
🏥 Sorin Group – Provides HIPEC and cardiac HCUs.
🏥 Cincinnati Sub-Zero (CSZ) – Offers hypothermia and hyperthermia therapy systems.
Hospitals should choose HCUs with advanced filtration, UV sterilization, and low contamination risks to improve patient safety.
