Unnecessary Alarms Research Articles

Mining redundant industrial alarm occurrences with association rules extraction and complex networks modeling

Alarm management is a research area that is growing rapidly on industrial automation. One of the major difficulties in alarm rationalization, in which the volume of generated alarms is reduced to an appropriate number so that a human being can handle them, is to identify patterns that might indicate unnecessary alarms in the middle of files and databases containing tens of thousands of daily records. This work presents a new approach to analyze alarm occurrences, combining several techniques, such as: sequence mining, association rules extraction with MNR (Minimum Non Redundant Association Rules), cross-correlation analysis, and complex network modeling for visualization. The combination of different techniques creates a more comprehensive alternative to the detection process. The solution's performance, in terms of accuracy, shows improvements over the current approaches, resulting in a more reliable and predictable alternative for identification of meaningful patterns.

Event correlation analysis for alarm system rationalization

AbstractEvent correlation analysis is a data‐mining method that detects statistical similarities among discrete occurrences of alarms or operations. By grouping correlated events based on degree of similarity, a policy for reducing alarms and operations can be designed more easily than by analyzing individual alarms and operations. In this study, event correlation analysis was applied to event log data at an Idemitsu Kosan ethylene plant in Japan to reduce the number of alarms and operations, where events are defined by both tag names and types of tag. The obtained results were helpful for identifying unnecessary alarms and operations, such as sequential alarms and routine operations, buried in a lot of noisy plant data. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.

Physiologic Monitoring Alarm Load on Medical/Surgical Floors of a Community Hospital

It has been known to the public that high frequency of false and/or unnecessary alarms from patient monitoring devices causes "alarm fatigue" in critical care. But little is known about the impact to care on the less acute patients located outside the critical care areas, such as the traditional medical/surgical (med/surg) floor. As part of a larger population management study, we initiated continuous physiological monitoring to 79 beds of floor patients in a community hospital. In order to qualify the patient monitoring alarm load for subacute medical and surgical floor patients, we assessed alarm data from April 2009 to January 2010. A standard critical care monitoring system (Philips IntelliVue MP-5 and Telemetry) was installed and set to the default alarm limits. All waveform data available for the patient (typically ECG, RESP, PPG at 125hz 8 bit), all alarm conditions declared by the monitoring system, and 1 minute parameter trend data were saved to disk every 8 hours for all patients. A monitoring care protocol was created to determine whether the patient was monitored via the hardwired bedside or wirelessly via telemetry. Alarms were not announced on the care unit but instead notifications were the responsibility of remote telehealth center personnel. We retrospectively evaluated the frequency of alarms over specific physiologic thresholds (n= 4104 patients) and conducted adjudication of all alarms based on a smaller sampling (n=30 patients). For all patients, the average hours of monitoring per patient were 16.5 hours with a standard deviation (s) of 8.3 hours and a median of 22 hours. The average number of alarms (all severities) per patient was 69.7 (s =90.3, median =28) alarms. When this is adjusted to the duration of monitoring, the average per patient, per day rate was 95.6 (s =124.2, median =34.2) alarms. The adjudicated sample (n=30 patients) resulted in 34% of critical alarms (lethal arrhythmias, extreme high or low heart rate [HR], extreme desaturation, apnea) being true and 63% of the high priority alarms (high or low HR, high or low RR, Low SpO(2), pause, Missed Beat, Pair PVCs, Pacer Not Pace, Non Sustain VT, Irregular HR, Multiform) being true. Analysis of alarm history resulted in the ability to reduce the HR alarm load by more than 50% with a simple limit adjustment of high HR from 120 to 130 bpm and a 36% or 65% reduction in SpO(2) alarm load by reducing the SpO(2) limit from 90% to 85% or 80% respectively. 1) Standard critical care alarm limits appear be too sensitive for subacute care areas of the hospital. 2) For most patients these alarm limits do not create a significant alarm load; however, for a small number of patients they cause a significant alarm load. 3) Alarm loads can be controlled with alarm limit settings appropriate to the population. 4) Current technology for HR and SpO(2) appear suitable for continuous monitoring of this population.

Letters to the Editor

Letters to the Editor

Insulin glargine and malignancy: an unwarranted alarm

Insulin glargine is a recombinant insulin analogue that has become widely used, largely because of a lower risk of hypoglycaemia and prolonged stable action. Synthetic insulins differ from human insulins in both metabolic and cell-growth activities, which raises legitimate concerns about risk of malignancy. 1 Smith U Gale EAM Does diabetes therapy influence the risk of cancer?. Diabetologia. 2009; (published online.)https://doi.org/10.1007/s00125-009-1441-5 Crossref Scopus (284) Google Scholar A recent observational study claimed an increased cancer incidence in people using glargine insulin compared with other human insulins, but this effect was only apparent after adjusting for dose. 2 Hemkens LG Grouven U Bender R et al. Risk of malignancies in patients with diabetes treated with human insulin or insulin analogues: a cohort study. Diabetologia. 2009; (published online June 30.)https://doi.org/10.1007/s00125-009-1418-4 Crossref Scopus (528) Google Scholar Subsequently, three further observational studies 3 Currie CJ Poole CD Gale EA The influence of glucose-lowering therapies on cancer risk in type 2 diabetes. Diabetologia. 2009; (published online July 2.)https://doi.org/10.1007/s00125-009-1440-6 Crossref Scopus (956) Google Scholar , 4 Jonasson JM Ljung R Talbäck M Haglund B Gudbjörnsdòttir S Steineck G Insulin glargine use and short-term incidence of malignancies—a population-based follow-up study in Sweden. Diabetologia. 2009; (published online.)https://doi.org/10.1007/s00125-009-1444-2 Crossref PubMed Scopus (371) Google Scholar , 5 SDRN Epidemiology GroupUse of insulin glargine and cancer incidence in Scotland: a study from the Scottish Diabetes Research Network Epidemiology Group. http://webcast.easd.org/press/glargine/download/090818Colhounacceptedpaperadjusted.pdf Google Scholar and one randomised trial 6 Rosenstock J Fonseca V McGill JB et al. Similar risk of malignancy with insulin glargine and neutral protamine Hagedorn (NPH) insulin in patients with type 2 diabetes: findings from a 5 year randomised, open-label study. Diabetologia. 2009; (published online.)https://doi.org/10.1007/s00125-009-1452-2 Crossref Scopus (129) Google Scholar have investigated whether insulin glargine is associated with cancer incidence. Insulin glargine and cancer: another side to the story?In their Comment (Aug 15, p 511),1 Stuart Pocock and Liam Smeeth review four papers2–5 and an editorial6 in Diabetologia, which raise concern about the possibility that insulin glargine might increase the risk of cancer, and declare that there is no conclusive evidence of this. They go on to remark that “claims of harm not backed by adequate evidence can provoke unnecessary alarms and anxieties”. Coming as it does from one of the iconic figures in medical statistics, this statement implies that the journal I edit has acted in an irresponsible and alarmist manner. Full-Text PDF

Detection of Hypoglycemia with Continuous Interstitial and Traditional Blood Glucose Monitoring Using the FreeStyle Navigator Continuous Glucose Monitoring System

The objective of the analysis was to compare detection of hypoglycemic episodes (glucose <70 mg/dL lasting >15 min) with the FreeStyle Navigator Continuous Glucose Monitoring System (FSN-CGM) (Abbott Diabetes Care, Alameda, CA) alarms to detection with traditional finger stick testing at an average frequency of eight tests per day. The performance of FSN-CGM alarms was evaluated in a clinic setting using 58 subjects with type 1 diabetes mellitus (T1DM) monitoring interstitial glucose concentration over a 5-day period compared to reference YSI measurements (instrument manufactured by YSI, Yellow Springs, OH) at 15-min intervals. Finger stick glucose testing was evaluated in the home environment with 91 subjects with TIDM monitoring with the blood glucose meter integrated into the FreeStyle Navigator (FSN-BG) over a 20-day period. The reference was FSN-CGM with results masked from the subjects. Blood glucose values <=85 mg/dL were considered the optimal treatment level to avoid or reverse hypoglycemia. With a threshold alarm setting of 85 mg/dL, 90.6% of hypoglycemic episodes were detected within +/- 30 min by FSN-CGM in the clinic study. When the alarm was activated, YSI glucose was <= 85 mg/dL 77.2% of the time. In the home environment, the average FSN-BG testing frequency was 7.9 tests per day. Hypoglycemia was verified within +/- 30 min by FSN-BG measurements <= 85 mg/dL at a rate of 27.5%. Even with a high rate of FSN-BG testing, hypoglycemia detected by FSN-CGM was verified by patients with T1DM very infrequently. A high rate of hypoglycemia detection with a moderate rate of unnecessary alarms can be attained using FSN-CGM.

Should we be alarmed by our alarms?

The number of alarms in the anaesthesia environment has gone from none to many dozens during the past 50 years. Until recently, each equipment manufacturer designed their own alarm set, resulting overall in a chaotic acoustic environment. Anaesthesiologists tend to have an uneasy relationship with monitoring alarms. On one hand they warn of mishaps, but on the other the many unnecessary alarms can be irritating and actually impede clinical care. There is evidence that these factors prevent alarms from realizing their full potential to enhance patient safety. This review explores current developments in clinical alarm design and technology. A considerable body of research currently exists on the design of nonverbal auditory alarms, their relationship with human behaviour, and implications for medical alarms. Technology to reduce the unacceptably high rate of false-positive alarms is being introduced. Much work has been done to standardize alarm conditions and alarm sounds. Although this is a work in progress, the introduction of these standards should make clinical alarms more useful and less grating. The disadvantages of current clinical alarms have been identified and are in the process of being addressed.

The influence of distraction and driving context on driver response to imperfect collision warning systems

Automotive collision warning systems (CWS) can enhance hazard identification and management. However, false alarms (FAs), which occur as a random activation of the system not corresponding to a threat and not interpretable by the driver, and unnecessary alarms (UAs), which occur in situations judged hazardous by the algorithm but not by the driver, may limit CWS effectiveness. A driving simulator was used to investigate the influence of CWS (accurate, UA, FA, none) and distraction on driver performance during non-critical and critical events. FAs and UAs differentially influenced trust and compliance. FAs diminished trust and compliance, whereas the context associated with UAs fostered trust and compliance during subsequent events. This study suggests current warning descriptions based on signal detection theory need to be expanded to represent how different types of alarms affect drivers.

Patients’ perception of sound levels in the surgical suite

Study Objectives: To measure sound levels that our patients are exposed to in the surgical suite and their perception of these sound levels. Design: Sound levels experienced by 100 patients undergoing general anesthesia for elective surgery during three phases: induction and maintenance of anesthesia in the operating room (OR), and recovery from anesthesia in the recovery room, were measured using a Type 4436 Noise Dose Meter. The equivalent continuous sound levels (Leq), maximum sound levels (Lmax), and the sources of sounds were noted. Patients were interviewed 24 hours after anesthesia about their perception of the sound levels they had experienced in the OR and recovery rooms. Measurements and Main Results: The Leq during the induction, maintenance, and recovery phases were 70.3 ± 16.8 dB(A), 66.2 ± 4.1 dB(A) and 71.8 ± 6.1 dB(A), respectively. These sound levels are much higher than international recommendations for hospital acute care areas and exceed the thresholds to produce noise-induced cardiovascular and endocrine effects. Sound levels were significantly higher during the induction and recovery phases compared to the maintenance phase. Thirty-two patients found the induction phase noisy and 33 patients found the recovery phase noisy. The sound levels distressed 16 patients and 52 patients would have preferred a quieter environment. There was no difference in the sound levels experienced by those who expressed dissatisfaction with the sound levels and those who did not. Much of the noise, particularly staff conversations, unnecessary alarms, and preparation of equipment, could have been prevented by simple measures. Conclusion: Noise prevention in the OR and recovery room needs more attention and should be a routine part of patient care.

A medication database--a tool for detecting drug interactions in hospital.

Drug interactions may lead to life-threatening injuries. More often, however, they lead to slow recovery, induce slight symptoms or result only in potential injury. Therefore, clinicians are not always aware of using potentially interacting drug combinations. An on-line alarming system of potential drug interactions was developed in Turku University Central Hospital. In the present study, we utilised the system to find out the incidence and nature of potential drug interactions occurring in a representative hospital patient population. Computerised anatomical therapeutic chemical (ATC)-coded patient medication data of 2547 patients, treated in two internal medicine wards, were combined with an ATC-coded rule base of drug interactions. All potential drug interactions in the study population were searched for. A total of 326 potentially serious drug interactions were detected in the study population. The number of patients in this group was 173, i.e. 6.8% of all patients had one or several drug combinations which might have led to serious clinical consequences. Concomitant use of calcium and fluoroquinolones (decreased absorption) was the most common mistake (66 prescriptions). Potentially inappropriate drug combinations seem to occur frequently. Structured and coded medication data can be utilised efficiently to detect potential drug interactions in hospital. Computerised online monitoring and automatic alarming of potentially hazardous drug combinations might help clinicians to prescribe more safely, but further development of the system is needed to avoid unnecessary alarms.

The interference suppression antenna for the near-field monitor of category III ILS

It is well known that the ILS Localizer (LLZ) course may be deviated by aircraft passing above the LLZ antenna. The course deviation is observed not only by other aircraft approaching to a runway but also by the ILS monitor. This phenomenon may cause an alarm in the ILS monitor and halt category III LLZ operation, because the tolerance for unexplained course deviation and its duration is tighter in category III LLZ than in other categories. In this paper, a new antenna (the interference suppression antenna) for the near field monitor (NFM) is proposed that can suppress unnecessary alarms generated by this phenomenon. First, the LLZ course deviation and its duration as observed by the NFM due to passing aircraft above the LLZ are analyzed. Next, the course deviation is calculated when the interference suppression antenna, which consists of an end-fire array antenna and a broadside array, is used. The relationship between the aircraft location, the course deviation, and its duration period as received by the NFM is determined. When this new antenna is used, the course deviation at the NFM and its duration can be reduced substantially from those obtained by the conventional antenna. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 1, 80(7): 51–60, 1997

New Concepts in Collision Avoidance Logic

Airborne collision avoidance logic is being developed to take advantage of the accurate bearing measurements provided by the Enhanced TCAS II system. This system issues horizontal and vertical resolution advisories, and should give fewer unnecessary alarms than earlier systems. Design tradeoffs and new techniques are described for threat detection, modeling of potential escape maneuvers, and the selection of resolution advisories. Plans for further development and evaluation are described.