New Study Finds that Dirty Stethoscopes May Spread Germs

By Kim Smiley

It’s been well documented that washing hands can prevent infections and in the same vein some researchers are now asking questions about potential contamination risks posed by stethoscopes and other small medical equipment used to examine multiple patients. In a recent study, stethoscopes were tested after they were used to examine patients and most were found to have bacteria on them.  Unlike the guidance provided for hand washing, there are currently no guidelines that require physicians to disinfect their stethoscopes between patients.

This issue can be analyzed by building a Cause Map, a visual format for performing a root cause analysis.  In a Cause Map, the causes that contribute to an issue are laid out to show the cause-and-effect relationships to aid in understanding the role the causes played.  The first step in the Cause Mapping process is to fill in an Outline with the basic background information for a problem such as the location and time it occurred.  Additionally, how the issue impacted the organizational goals is documented on the Outline.  The possibility of patient exposure to bacteria is an impact to the safety goal in this example.  Once the impact to the organizational goals is defined, the Cause Map is built by asking “why” questions.

Why is there a risk of patient exposure to bacteria?  This is happening because a contaminated stethoscope may be placed on a patient’s skin.  Stethoscopes are commonly used to listen to a patient’s heart and lungs and they work best when placed directly onto the skin.  Stethoscopes may get contaminated from being used on a person with bacteria on their skin and stethoscopes are not necessarily cleaned between uses.  Stethoscopes aren’t always cleaned between uses because there are currently no guidelines requiring it.  There aren’t any guidelines because it hasn’t been clear if they are needed.  There has been limited research done to understand the issue and determine how much of a risk of illness a contaminated stethoscope may pose, especially if used on healthy skin.

The new study is a good early step in understanding the issue, but it was a relatively small study and a larger scale study may be needed in the future.  The study “Contamination of Stethoscopes and Physicians’ Hands after a Physical Examination” looked at the stethoscopes used by three physicians as they examined a total of 83 patients in a Swiss hospital.  The researchers found bacteria on the stethoscope after 71 of the patient examinations.  It’s also difficult to determine whether bacteria on stethoscopes is responsible for spreading bacteria and whether it has actually caused illness.

The final step in the Cause Mapping process is to come up with solutions that can reduce the risk of the problem recurring in the future.  One good thing about this particular issue is that the solutions are relatively easy and cheap.  Physicians who are concerned about the cleanliness of their stethoscopes can either give them a give clean with disinfectant between patients or use disposable covers that are already commercially available.  Guidelines about cleaning stethoscopes are likely years in the future, but you can always ask your physician about the issue or to clean the stethoscope if you are concerned.