A novel wall water system for cardiopulmonary bypass may reduce the risk of aerosolized infection.

OBJECTIVE: Oxygenators for cardiopulmonary bypass require water flow for their integral heat exchanger. Heater-cooler units are nearly universally used for this requirement. Heater-cooler units pose the risk of aerosolized infection. The Centers for Disease Control and Prevention recommended discontinuing use of Stöckert 3T heater-cooler units (LivaNova PLC, London, United Kingdom) in October 2016 because of this risk. We aimed to reduce the risk of aerosolized infection posed by heater-cooler units by eliminating those devices from our operating rooms. METHODS: The cardiac surgery division collaborated with in-house specialties to engineer a novel wall water system. The design called for service to 4 operating rooms with the actual water mixing valve in an operating room closet. Remote temperature control was mounted next to the heart-lung machine. Primary safety systems built into the water system include 5 µm filtration, pressure regulating and relief valves, flow quantifiers, limits to the hot and chilled input temperatures, and a novel bridge near the heart-lung machine that allows the perfusionist to test the system before patient use and to quickly disconnect the patient in case of system malfunction. In addition, all water line connections can be made with the tubing drained and never under pressure. RESULTS: This novel wall water system has successfully provided heat exchanger water flow on 625 patients undergoing congenital heart surgery requiring cardiopulmonary bypass during its first 9 months of use. CONCLUSIONS: Wall water systems are an option for oxygenator heat exchangers that allow for improved heat exchange performance while reducing the risk of heater-cooler unit-associated infection during cardiac surgery.

Nontuberculous Mycobacterium Infections Associated With Heater-Cooler Devices.

BACKGROUND: Disseminated nontuberculous mycobacterium infections have occurred following surgical procedures involving extracorporeal circulation; contaminated water from heater-cooler devices (HCDs) has been implicated as the source. The purpose of this review was to evaluate the public health concern and to educate physicians who care for this patient population. METHODS: The Food and Drug Administration Medical Device Reporting (MDR) database was queried for reports received between January 2010 and August 2016 for patient infections and device contaminations associated with the use of HCDs. Reports were reviewed for type of infection, patient demographics or outcome, reporting country, HCD manufacturer, and the time to event occurrence. RESULTS: A total of 339 MDR reports involving 99 facilities and 5 HCD manufacturers were found. MDR reports originated within (n = 154) and outside the United States (n = 185), and included 107 MDR reports describing patient infections involving at least 86 patients and 232 MDR reports describing HCD contamination without known patient infections. The MDR reports identified the surgical procedure in 94 reports and infection location in 83 reports. The time from surgical procedure using an HCD to infection diagnosis was calculable in 67 reports and was reported up to 60 months following the initial surgery. Nontuberculous mycobacterium was the most frequent organism identified, with M. chimaera being the predominate isolate. CONCLUSIONS: Nontuberculous mycobacterium infections associated with HCDs used during cardiothoracic surgery may have a long latency period and may be lethal. Cardiothoracic surgeon awareness or involvement in this issue is critical in helping to mitigate this emerging public health concern.

Safety of heart-lung machines during prolonged standby.

BACKGROUND: Coronary artery bypass surgery is increasingly performed without an extra-corporeal circuit. A heart-lung machine (HLM) is kept on standby for safety reasons, but rarely used. The tubes of the machines are currently discarded after every operation. Costs and waste would be avoided if HLMs could stay on standby for longer periods of time. We therefore investigated the sterility of intra-tube fluid over time. MATERIALS AND METHODS: Four machines were tested. The tube system was fixed and filled with priming solution. Samples of intra-tube fluid and fluid from the fluid bags were taken after 0, 12, 24, 36, 48 and 72 h. Microbiological cultures were performed by direct inoculation and membrane filtration and incubated up to 14 days. Endotoxin levels were also determined. RESULTS: Bacteria were grown from two samples only and were considered as contaminants. Endotoxin concentrations never exceeded acceptable levels. CONCLUSION: To keep HLMs on standby for 72 h is probably safe. The prolonged use of HLMs will contribute to cost and waste reduction in open heart surgery.