Measures for improved patient safety in cardiac surgery

Press release about heater cooler devices Bern, 14.07.2014

Hospitals in Switzerland that perform open heart surgery have taken measures to increase patient safety. In rare cases, infections have been observed that did not result in illness until some years after surgery. These infections are believed to be due to the use of a device that is used during cardiac surgery. In conjunction with Swissmedic, the Federal Office of Public Health has informed all hospitals and cardiac surgeons about this problem. Immediate measures are being taken to prevent such infections from occurring in future.

The Federal Office of Public Health (FOPH) was informed that rare cases of infection with the bacterium Mycobacterium chimaera were detected after cardiac surgery involving implants. This bacterium occurs naturally in the environment (for example in drinking water) and is usually harmless. However, in certain cases, co-occurrence of particular circumstances in the operating theatre may result in infections that can lead to serious disease one or two years later.

The cause of the infection is suspected to be the contamination of a technical device (heater cooler unit) that is used in hospitals during open heart surgery to control the temperature of the blood. These devices are operated with filtered tap water. The bacterium was detected in the water and in the discharged air of the devices in several Swiss hospitals. It is possible that during very few of these operations, a transmission of the bacterium occurred. However, the exact route of transmission has not yet been established.

An enquiry commissioned by the FOPH found that such heat exchange devices are used in all 16 Swiss hospitals that perform cardiac surgery. The FOPH has informed all hospitals and, via the Swiss Society for Cardiac and Thoracic Vascular Surgery, all cardiac surgeons who operate in those hospitals. All these devices are now being examined, and immediate measures are being taken to prevent any further infections. So far Mycobacterium chimaera has been identified in three hospitals; the results in the other hospitals are still pending, since confirmation of these bacteria can take up to seven weeks.

It is a credit to the hospital hygienists and infectious disease physicians at the University Hospital Zurich (USZ), as well as to the microbiologists of the University of Zürich (IMM, UZH), that they were the first in Switzerland (and worldwide, to the best of our knowledge) to identify the possible cause of this problem thanks to their comprehensive investigations, and to inform the FOPH accordingly. The USZ and the UZH have thus drawn attention to a fundamental problem, the extent of which is currently being clarified in Switzerland in the interest of patient safety. The USZ has been able to identify all six patients known to be affected; all underwent surgery between 2008 and 2012.

The USZ has made its expertise and experience in dealing with the affected devices available. The devices have received specific servicing and have remained sterile since then. Current investigations suggest that devices from various manufacturers are affected. As the authority responsible for monitoring medical products, Swissmedic reviews the corrective measures taken by the manufacturers and hospitals that are responsible for the operation of these devices. Swissmedic has also informed the regulatory authorities of the other European countries about these findings.

Investigations in the hospitals were coordinated by the FOPH and carried out in close cooperation with Swissmedic, Swissnoso, the responsible cantonal health directorates and the hospitals. Their common goal is to prevent future occurrence of such infections.

Since 2008, in 16 cardiac surgery departments in Switzerland about 20,000 open heart interventions have been performed, during which implants were inserted using the support of cardiac heater cooler units. Based on the experience in Zurich, it can be assumed that no more than 40 patients could have been infected with the bacteria in Switzerland. Such infections of cardiac implants result in changes that can be detected by cardiologists as part of the routine annual checkup. The FOPH recommends that patients contact their cardiologist if they have been given an artificial heart valve or similar implants of foreign material and have any concerns. The FOPH has set up a special phone number to answer any questions that patients may have (031 322 21 00, available from 8h to 18h).


Federal Office of Public Health, Communication

+41 58 462 95 05

Swissmedic, Swiss Agency for Therapeutic Products
Lukas Jaggi, Acting spokesman

+41 58 462 00 59

Hotline FOPH

Special phone number for patients (from 8h to 18h)
+41 31 322 21 00

Print contact