Quan Ding

Insights into the problem of alarm fatigue with physiologic monitor devices: a comprehensive observational study of consecutive intensive care unit patients.

Purpose Physiologic monitors are plagued with alarms that create a cacophony of sounds and visual alerts causing “alarm fatigue” which creates an unsafe patient environment because a life-threatening event may be missed in this milieu of sensory overload. Using a state-of-the-art technology acquisition infrastructure, all monitor data including 7 ECG leads, all pressure, SpO2, and respiration waveforms as well as user settings and alarms were stored on 461 adults treated in intensive care units. Using a well-defined alarm annotation protocol, nurse scientists with 95% inter-rater reliability annotated 12,671 arrhythmia alarms. Results A total of 2,558,760 unique alarms occurred in the 31-day study period: arrhythmia, 1,154,201; parameter, 612,927; technical, 791,632. There were 381,560 audible alarms for an audible alarm burden of 187/bed/day. 88.8% of the 12,671 annotated arrhythmia alarms were false positives. Conditions causing excessive alarms included inappropriate alarm settings, persistent atrial fibrillation, and non-actionable events such as PVCs and brief spikes in ST segments. Low amplitude QRS complexes in some, but not all available ECG leads caused undercounting and false arrhythmia alarms. Wide QRS complexes due to bundle branch block or ventricular pacemaker rhythm caused false alarms. 93% of the 168 true ventricular tachycardia alarms were not sustained long enough to warrant treatment. Discussion The excessive number of physiologic monitor alarms is a complex interplay of inappropriate user settings, patient conditions, and algorithm deficiencies. Device solutions should focus on use of all available ECG leads to identify non-artifact leads and leads with adequate QRS amplitude. Devices should provide prompts to aide in more appropriate tailoring of alarm settings to individual patients. Atrial fibrillation alarms should be limited to new onset and termination of the arrhythmia and delays for ST-segment and other parameter alarms should be configurable. Because computer devices are more reliable than humans, an opportunity exists to improve physiologic monitoring and reduce alarm fatigue.

Robust QRS peak detection by multimodal information fusion of ECG and blood pressure signals

QRS peak detection is a challenging problem when ECG signal is corrupted. However, additional physiological signals may also provide information about the QRS position. In this study, we focus on a unique benchmark provided by PhysioNet/Computing in Cardiology Challenge 2014 and Physiological Measurement focus issue: robust detection of heart beats in multimodal data, which aimed to explore robust methods for QRS detection in multimodal physiological signals. A dataset of 200 training and 210 testing records are used, where the testing records are hidden for evaluating the performance only. An information fusion framework for robust QRS detection is proposed by leveraging existing ECG and ABP analysis tools and combining heart beats derived from different sources. Results show that our approach achieves an overall accuracy of 90.94% and 88.66% on the training and testing datasets, respectively. Furthermore, we observe expected performance at each step of the proposed approach, as an evidence of the effectiveness of our approach. Discussion on the limitations of our approach is also provided.

AUTOMATED DETECTION OF CHANGES IN ELECTROCARDIOGRAPHIC METRICS ON CONTINUOUS TELEMETRY PRECEDING IN-HOSPITAL CARDIAC ARRESTS

Despite advances, survival to discharge following in-hospital cardiac arrests (IHCA) remains less than 30%. We have previously shown that PR interval and QRS duration can prolong preceding IHCA, especially in bradyasystole cases. Our goal is to determine if electrocardiogram (ECG) changes prior to

On the Design and Implementation of a Highly Accurate Pulse Predictor for Exercise Equipment

Goal: This study aims to develop highly accurate heart rate monitoring from the hand-held contact signal within a noisy environment during exercise. Methods: The periodic pattern and uncertainties of a physiological signal are modeled by a Laplacian random process. Based on this statistical model, a highly accurate pulse predictor (HAPPEE) is derived and implemented in real-time on a Cypress PSoC 5LP development board. A real-time experiment is designed to compare HAPPEE with a commercial heart rate monitor from POLAR. The percentage of credible estimates and the mean square error (MSE) of credible estimates are reported for experiments with seven healthy subjects. Results: The overall percentage of credible estimates is 99.2% for HAPPEE and 93.6% for POLAR. The overall MSE of credible estimates is 3.1 for HAPPEE and 7.7 for POLAR. These results show that HAPPEE is more accurate than POLAR. Conclusion: HAPPEE is able to accurately monitor heart rate within a noisy environment during exercise. Significance: Unlike existing heart rate estimation methods, HAPPEE does not require pulse detection or tuning parameters. It can be easily implemented in real-time on a low power and low cost development board for exercise equipment and outperforms a commercial heart rate monitor.