Effect of Monitoring System Design on Response Time to Cardiac Arrhythmias

Most patients in the hospital who are at lower risk for developing abnormal heart rhythms have their vitals signs (e.g., heart rate, blood pressure) measured intermittently, such as every 8 hours. In contrast, hospitalized patients who are at risk for cardiac arrest and other arrhythmias are put on telemetry to continuously monitor their heart rhythm. A telemetry monitor is a portable box that is attached to the patient's ECG leads and displays his or her heart rate and rhythm at a central station. The monitor sends an alarm when it detects an abnormal rhythm, notifying the person monitoring the patient to check on the patient. Monitor watchers are dedicated nurses or technicians who monitor a bank of displays . The watcher-to-patient ratio varies among hospitals, with a single watcher monitoring between 16 and 72 patients at one time. There are also variations in the additional tasks assigned to watchers, communication modalities between watchers and nurses (e.g., pagers, overhead speakers, landline and cell phones, or bi-directional voice communication badges), and alarm presentation to nurses (e.g., via bedside monitors, centrally located monitors, automated phone notifications, or none at all, relying on telemetry watchers for notifications).

A quick and efficient response to cardiac arrest is critical in order to increase the patient's chance of survival. There is a need for a better understanding of the impact on monitoring efficiency of factors such as the workload of monitor watchers, communication methods, and supportive technologies including alarms and automated notification systems. The objective of the proposed research is to identify and test determinants of efficient cardiac monitoring methods. There are 3 phases to the study:

1. Characterize candidate monitoring methods (Phase 1). The investigators will study usual care for monitored patients in 6 hospital units. As part of their usual care these units have different monitoring methods. These methods vary in terms of 1) the location of the monitor watchers, 2) the means of communicating routine and life-threatening events (e.g., via pagers), and 3) monitor watchers' patient load and workload. For each of these 6 units, the investigators will collect data through interviews, observations, and 20 cardiac arrest simulations.
2. Determine which monitoring method leads to consistently rapid response times to lethal arrhythmias (Phase 2). Using interview, observation, and simulation data collected in Phase 1, the investigators will develop a computer simulation model of each of the 6 monitoring methods that will allow them to identify the most efficient method.
3. Test a new monitoring method (Phase 3). In one of the units we had previously conducted arrhythmia simulations, we will conduct 20 additional simulations after a change from remote telemetry monitoring to local nurse-based monitoring. We will evaluate whether response times decrease with the new monitoring method.