$7.65 Million Verdict in KU Medical Heater-Cooler Infection Case Highlights Ongoing Risks of Mycobacterium chimaera in Cardiac Surgery

A Wyandotte County jury has awarded $7.65 million in damages to the family of a Missouri man who died after contracting a rare but devastating infection following open-heart surgery at The University of Kansas Hospital Authority. The case is drawing renewed attention to the persistent infection risks associated with heater-cooler devices used during cardiothoracic surgery.

The lawsuit centered on the death of Stephen Nolte, a 71-year-old US Navy veteran and retired electrician who underwent an aortic valve replacement at The University of Kansas Medical Center (KU Med) in March 2019. Nolte later developed Mycobacterium chimaera infection and died in July 2020.

After nearly 2 weeks of testimony, jurors attributed 88% of the fault to The University of Kansas Hospital Authority and 12% to LivaNova, the manufacturer of the heater-cooler devices involved in the surgeries.

The jury awarded $3 million for noneconomic damages related to the personal injury claim. For the wrongful-death claim, they awarded $650,000 for economic loss, $550,000 for future economic loss, $2.7 million for noneconomic loss incurred thus far, and $750,000 for future noneconomic losses.

The case is one of more than 2 dozen lawsuits filed against KU Med and LivaNova involving allegations that contaminated heater-cooler devices exposed cardiac surgery patients to M chimaera, a slow-growing nontuberculous mycobacterium linked to severe and often fatal infections. According to court filings, at least 25 patients allegedly contracted infections tied to the devices, and 11 patients died.

Heater-cooler devices are commonly used during bypass procedures to regulate patient temperature while the patient is connected to heart-lung machines. Studies have shown that contaminated water tanks inside the devices can aerosolize bacteria into the operating room environment, potentially exposing patients during open-chest surgery.

The trial focused heavily on cleaning and disinfection practices.

According to testimony, KU Med had initially followed LivaNova’s instructions for use, from July 1, 2017, through Oct. 16, 2018, including routine bleach disinfection and hydrogen peroxide treatment. During that period, no confirmed M chimaera infections were identified.

However, in October 2018, the hospital’s chief perfusionist, Jamie Newberry, reportedly discontinued those disinfection procedures and instead instructed staff to drain the water tanks daily. At the time of Nolte’s surgery in March 2019, the device involved had reportedly not been disinfected for approximately 5 months.

During closing arguments, attorney Lynn Johnson told jurors the failures created catastrophic consequences.

“He went through hell,” Johnson said of Nolte. “He was doing well until the disseminated M chimaera started eating away at his organs.”

Johnson argued that the outbreak resulted from multiple failures, including inadequate disinfection, device design flaws, and alleged contamination during manufacturing. He told jurors that all affected patients shared “1 and only 1 thing in common”: a LivaNova heater-cooler device present during surgery.

LivaNova denied responsibility and argued that the infections stemmed solely from the hospital’s decision to stop disinfecting the units according to the manufacturer’s instructions.

“The risk was rare,” attorney David Gross told jurors, emphasizing that both the US Food and Drug Administration (FDA) and CDC continued supporting use of the devices provided that cleaning protocols were strictly followed. Nolte “died with M chimaera,” he said, “not from M chimaera.”

Gross described the hospital’s decision to abandon routine disinfection as “a bacterial experiment.”

The FDA has previously warned that M chimaera infections associated with heater-cooler devices may take months or even years to appear, making detection especially difficult. Symptoms can include fever, fatigue, weight loss, night sweats, and organ dysfunction, often delaying diagnosis until the infection becomes advanced.

Although rare, these outbreaks have prompted global concern within infection prevention and cardiac surgery communities over the past decade. Hospitals nationwide have strengthened maintenance, monitoring, and water management procedures in response.

The verdict underscores the continued importance of strict adherence to device disinfection protocols, environmental monitoring, and multidisciplinary oversight of surgical equipment.

KU Med reached a confidential settlement with the Nolte family shortly before trial, but the jury’s decision marks one of the most notable public legal outcomes related to heater-cooler-associated M chimaera infections in recent years. The University of Kansas Hospital Authority s settled with the Noltes prior to the trial, and District Court Judge Courtney Mikesic approved this settlement on Monday, dismissing the University of Kansas Hospital Authority as a defendant. The dismissal was entered “with prejudice,” meaning the case is permanently closed and cannot be refiled. Each party is responsible for its own costs, as set out in the order.