Auditory Alarms in Critical Care Settings:
Major Projects
Auditory Alarms in Critical Care Settings
Major Projects
Silencing Alarms
Problems with alarms was demonstrated in the results of a study reviewing 47 videotaped cases of airway management. In 46 cases, auditory alarms occurred from one or more of the three studied devices (blood pressure/heart-rate monitor, end-tidal CO2/pulse oximetry monitor, and ventilators). The three monitoring devices often sounded alarms multiple times during airway management, particularly the ventilator (2.7 times each case). The majority of all alarms from the three monitoring devices were superfluous: 85 percent of the ventilator alarms, 56 percent of the BP/HR monitor alarms, and 72 percent of the ETCO2/SPO2 alarms were of no value to the care providers. At the same time, care providers silenced a large portion of the alarms. Ninety percent of the ventilator alarms, 66 percent of the BP/HR monitor alarms and 18 percent of the ETCO2/SPO2 alarms were silenced. People silenced loud alarms (ventilator) more often and more quickly than softer alarms. In one case, the ventilator alarms were silenced within 0.9 seconds of sounding. Under these conditions, it is questionable whether any useful information was transmitted by alarms to the operators, or whether responses to alarms venture far beyond knee-jerk reactions to loud sounds.
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Operating Room observation study
This paper describes an observational study of anesthetists' response to alarms in the operating room across four different types of procedure (laparoscopic, arthroscopic, cardiac, and intracranial) and three phases of a procedure (induction, maintenance, and emergence). Alarms were classified as requiring a corrective response, being intended, being ignored, or functioning as a reminder. Results revealed quite strong effects of the type of procedure and phase of procedure on the number and rate of alarms. Responses to alarms such as apnea varied strongly across phase, whereas other alarms were confined to specific situations. These results were interpreted in light of their significance for the development of smart alarm systems.
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Operating Room Observation with Eye-tracking
Information provision is an important function of most technology interventions. Understanding human operators' patterns in consulting various information sources could provide insights into how displays should be designed. We tested the utility of an ambulatory eye-tracker in an operational setting for collecting data of monitoring behavior. Temporal patterns of eye-tracking data, coupled with the data on observed activities and events led to a model of monitoring that treats knowledge about the monitored process as a resource. In a semi-self-paced work environment, the operator could deploy the strategy of building up knowledge about the monitored process before anticipated high workload periods and reestablishing such knowledge immediately after high workload periods to replenish lost resources. Through measures of monitoring frequency and time series analysis, supportive evidence for the resource model was obtained from the eye-tracking data of the pilot study. The study successfully demonstrated the utility of an ambulatory eye-tracking device in a real, dynamic environment.
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Operating Room Experiment with Eye-tracking
We report here the results of observations made during experiments conducted using eye-tracking techniques to determine patterns of information during real and simulated anesthesia cases. We classify monitoring behaviors into four categories of information seeking, and discuss the implications of these behaviors for design of informative auditory displays.
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Simulation Experiment with Eye-tracking
Using the realistic patient simulator of USUHS, simulated anesthesia cases were run with anesthetists managing (a) normal cases, as well as (b) cases involving difficult airway management, and (c) diagnosis and treatment of a pneumothorax. Eye tracking methods were used to record what the anesthetist looked at; video was used to record anesthetist activity and actions; and physiological measures were recorded to measure stress.
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Alarms and Informative Auditory displays
Auditory signals can take the form of “auditory displays” that communicate information redundant to visual displays. These redundant displays may allow offloading some visual workload to the auditory channel. This study examines the effect of visual, auditory and redundant displays on the performance of a dual-task simulation of patient monitoring. Subjects performed manual compensatory tracking task while monitoring six vital signs of a simulated patient, detecting deviations from normal levels. Monitoring was presented in three display conditions: auditory only, visual only, and redundant. Results indicate that the detection of deviations in visual and redundant conditions were not significantly different, but faster than the auditory display. However, performance in the tracking task was degraded least in the auditory condition, and the redundant display resulted in poorest performance—an example of a negative redundancy-gain. Reasons for this finding are examined through data from eye-movement recordings. This negative redundancy gain is also discussed
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