Electrostatic Charging of a Human Body Caused by Activities and Material Combinations in Hospitals

Electrostatic charging of hospital personnel and patients during various activities increases the risk of electrostatic discharge (ESD) malfunctions of medical devices and the likelihood of patients' adverse events. Therefore, the test level for ESD immunity of medical devices, specified in the IEC 60601-1-2 standard needs to reflect the reasonably maximum electrostatic voltages during usage. This study investigated the effects of material combinations and relative humidity on the body voltage while performing two routine clinical activities of lying down on a hospital bed and transferring to a bed using a sliding board. The peak body voltages in nearly 50% of the lying down experiments and 40% of sliding tests exceeded the test voltage level in the IEC 60601-1-2 standard (i.e., 15 kV). Using cotton blankets in lying down experiments and nylon sheets during sliding experiments resulted in 50% and 40% larger median than the median including all combinations, respectively. Sliding boards with antistatic coating reduced the peak body voltage by 24% on average, however, 33% of the tests still exceeded 15 kV. Based on the findings, recommendations are provided for healthcare facilities and medical device manufacturers to mitigate the risks of ESD malfunctions.

I. Introduction

An Ever-Increasing reliance on electronics in medical equipment requires close supervision of their reliability and factors that may lead to wrong data, disturbances, damage, and safety issues. However, the discharge of static electricity can cause failure of electronics, render the medical devices unreliable, and jeopardize patients’ safety [1]–[3]. In fact, our analysis of the adverse event reports of the U.S. Food and Drug Administration (FDA) revealed that electrostatic discharge (ESD) failures are a significant problem in medical devices [3], [4]. During the 10-year period between 2006 and 2016, our analysis found 1342 reports related to ESD malfunctions in the FDA's adverse event databases [4]. These reports noted 5 patient deaths and 46 injuries where ESD may have occurred and caused device malfunction [4].