Chemical in Plastic Medical Devices May Be Responsible for Decreased Heart Function

A chemical that is often used to create plastic medical devices, such as ITV tubing and catheters, has been shown to impair heart function in rats, and may be part of the reason why side affects like loss of taste and short-term memory problems occur after medical procedures that require blood to be circulated outside of the body in plastic tubing.

Artin Shoukas, PhD, professor of biomedical engineering, physiology and anesthesiology and critical care medicine at Johns Hopkins, where the study was performed, and colleague Caitlin Thompson-Torgerson, PhD, a postdoctoral fellow in anesthesiology and critical care medicine, hypothesized that the side affects may be set off by some sort of chemical compound.

Samples were taken from liquid IV bags and bypass machines before they were used on patients. The researchers used a machine capable of identifying chemicals to analyze the chemicals in both the IV bags and the bypass machines and found cyclohexanone, in varying amounts, in the fluid, which they thought may have leaked through the plastic and gotten into the solution.

Rats were then injected with either a salt solution or a salt solution containing cyclohexanone. Those given the chemical “pumped only about 150 microliters of blood per heartbeat with an average heart rate of 287 beats per minute.” Rats injected only with salt solution “pumped approximately 200 microliters of blood per heartbeat and had an average heart rate of 358 beats per minute.”

The cyclohexanone produced a 50 percent reduction in heart contractions in the injected rats. Blood pressure control was weaker in these rats, and fluid retention and swelling increased.

The researchers said that their next step is to uncover how, exactly, the side affects occur and how much of a role cyclohexanone plays in them.

Despite the study findings, Shoukas and Thompson-Torgerson caution that patients should still regard the advice of their physicians with importance and never “decline this type of treatment if they need it.”

“On the contrary, such technologies are life-saving medical advances, and their benefits still far outweigh the risks of the associated side effects,” Shoukas said. “As scientists, we are simply trying to understand how the side effects are triggered and what the best method will be to mitigate, and ultimately remedy, these morbidities.”