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A Pilot Study of Continuous QTc Interval Alarms in the Adult Intensive Care Unit


Background: QT-interval monitoring is an important tool in the prevention of ventricular arrhythmias, particularly for ICU patients, who often have multiple risk factors for QT prolongation. Manual QT measurement (current method) is inconsistent and time consuming. Algorithm-based QT-interval monitoring added to continuous bedside electrocardiographic monitoring is more efficient and reliable, but this technology is a relatively new feature; its value in the clinical setting, particularly with regard to alarms and alarm fatigue, is not known. Purpose/Aim: This pilot study, that included six intensive care unit (ICU) patients during a twenty day period who had QT-interval alarms enabled, was designed to determine: 1) the number of QT-interval alarms and escalation alarms (i.e., further increases in the QT-interval after an alarm); and 2) the clinical circumstances of the six patients. Methods: Secondary analysis of data from the University of California San Francisco (UCSF) Alarm Study. Results: During 56 days and 4.5 hours of monitoring time, the six patients had a total of 32 QT-interval alarms and 33 escalation alarms, for a total of 65 QT-interval alarms. New QT-interval alarm counts were as follows: three patients had one alarm; the other three had 8, 9, and 12 alarms each. The total duration of QT-interval alarms ranged from 27 seconds (patient with one alarm), to 53 minutes, 53 seconds (patient with 9 alarms and 19 escalations). No patients experienced ventricular arrhythmias. Conclusion: In this pilot study, we found a small number of QT-interval alarms during a 20-day monitoring period. False alarms often coincided with admission times, or patient transport. In the three patients with most alarms, the alarms were concentrated around medication administration times, or following a known QT prolonging drug; this finding suggests QT-interval alarms occur after certain medications are administered. However, a much larger study is needed to further validate/describe this finding.

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