Latency of ECG Displays of Hospital Telemetry Systems

Abstract

Recent observations indicate that some hospital telemetry systems used for monitoring of patient heart rhythm have clinically significant latency, or delay between the real-time status of the patient and the ECG information displayed on the patient monitor. If these systems are used for clinical care that requires instantaneous monitoring, then patient safety may be compromised. The purpose of this advisory is to inform healthcare providers about this potential problem, clarify the intended use of the systems, detail measures to reduce risk, and recommend steps to manufacturers and stakeholders to minimize this problem in current and future telemetry systems. Wireless telemetry electrocardiographic monitoring is a cornerstone of hospital management for patients with cardiovascular conditions or at risk for cardiovascular conditions. Since the first transmission of an ECG by telephone wire by Willem Einthoven was reported in 1906,1,2 advances in signal processing and communications have led to rapid innovation in wireless communication for telemetry systems in acute care settings.3 The first wireless systems introduced in the 1970s were fairly simple in design. They transmitted analog telemetry signals using 1 dedicated frequency channel for each patient.4 In the 1980s, networked telemetry systems led to the creation of centralized telemetry viewing stations in intensive and acute care units. Starting in the 1990s, digital telemetry systems allowed for computerized signal recording, storage, and retrieval.5,6 As computing power increased, the networking capability of these systems increased, allowing for monitoring of electrocardiographic, hemodynamic, and other clinical data from multiple patients on a single networked system. By 2000, wireless communication in the hospital extended beyond telemetry systems, and the US Federal Communications Commission established a protected range of frequencies for wireless medical devices to minimize electromagnetic interference from other in-band radiofrequency sources.7,8 Today, networked wireless telemetry systems …