Management of ECG Cables and Leadwires

Abstract

Electrocardiography (ECG) is the non-invasive capture and display (either on a screen or as a hard copy, such as a strip recording or page printout) of cardiac electrical activity. ECG provides a quick and highly reliable estimate of a patient’s cardiovascular health, making it one of the most common non-invasive medical applications. ECG is used for monitoring cardiac activity, for the purpose of diagnosis and therapy in clinics, and all areas of the hospital, including operating rooms and intensive care units (ICU). Physicians can use ECG to quickly measure heart rate and cardiac rhythm of a patient. The physician can also identify abnormalities in how electrical impulses propagate through the heart and detect evidence of coronary artery disease, prior heart attacks, and thickening of the cardiac muscle.1–4 For more detailed information about a patient’s cardiac electrical activity, a physician may request longer-term ECG recordings through the use of a Holter monitor (an ambulatory ECG) or during intentionally “loading” of the heart with a stress test, such as having the patient exercise on a treadmill. Continuous ECG monitoring during anesthesia provides vital information regarding a patient’s condition throughout a surgical procedure. Continuous ECG data acquisition using a bedside monitor provides real-time health information for a patient in an ICU. In some instances, pacemakers or defibrillators (external and internal) significantly alter the appearance of the body-surface ECG. Many medical activities, including life supporting or life saving ones, depend on efficient acquisition of ECG data. ECG has been used since Willem Einthoven invented the first practical ECG in 1903, receiving the Nobel Prize in Medicine in 1924 for his invention.5 ECG systems have evolved over many years. Now, ECG systems are built with similar building blocks, and all have similar external components. Electrical or mechanical failures occur infrequently for ECG devices themselves; however, malfunctions due to problems with ECG electrodes, leadwires, and ECG (patient) cables are common.6 This article reviews these problems and presents the results from a 2010 AAMI survey of biomedical equipment technicians (BMET)s and clinical engineers (CE)s. The article covers issues related to clinical management of the cables and leadwires, as well as potential improvements in the design of new medical devices to increase efficiency and reliability. ECG cables, leadwires, and electrodes are used to connect the human body to many different types of ECG devices. Hospitals usually have many medical devices that record and display ECG signals including Holter monitors, stress-testing equipment such as treadmills, patient monitors, telemetry units, defibrillators, and diagnostic electrocardiographs (often referred to as ECG or EKG carts). Large multi-specialty clinics may have treadmills and Holters, but these are generally run through a cardiology subspecialty group. (Smaller clinics and physicians’ offices also use some of these devices, but patient monitors and telemetry units are typically not on site.) These facilities stock large numbers of ECG cables, leadwires, and electrodes needed to use these devices. Poor electrodes and worn-out leadwires or ECG cables routinely cause failures that clinical users may not be able to readily identify. ECG cables and leadwires should be tested by a BMET regularly—or whenever an ECG device seems to be malfunctioning—and replaced when necessary. Leadwires should only be used if they remain in good condition (i.e., intact insulation, unbroken, no visible signs of wear). If a BMET is not available, cliniAhmet Turkmen, PhD, MS, BS, is an assistant professor with the Engineering and Technology Department at the University of Wisconsin–Stout. He is a co-chair of the AAMI ECG Committee. E-mail: turkmena@ uwstout.edu