Ergonomics in Design The Quarterly of Human Factors Applications http erg sagepub com This is your heart speaking Call 911 Mary Carol Day and Christopher Young Ergonomics in Design The Quarterly of Human Factors Applications 2012 20 4 DOI 10 1177 1064804611435652 The online version of this article can be found at http erg sagepub com content 20 2 4 Published by http www sagepublications com On behalf of Human Factors and Ergonomics Society Additional services and information for Ergonomics in Design The Quarterly of Human Factors Applications can be found at Email Alerts http erg sagepub com cgi alerts Subscriptions http erg sagepub com subscriptions Reprints http www sagepub com journalsReprints nav Permissions http www sagepub com journalsPermissions nav Citations http erg sagepub com content 20 2 4 refs html Version of Record Apr 20 2012 What is This Downloaded from erg sagepub com at HFES Human Factors and Ergonomics Society on April 24 2012 f e a t u re This is your heart speaking Call 911 Implantable vibrotactile alarms show great potential as early warning devices to prevent damage and death from heart attacks By Mary Carol Day Christopher Young FEATURE AT A GLANCE Early warning for heart attacks could save many lives We conducted three studies to design and evaluate multimodal alarms and patient training for an implanted heart attack detector An implanted device provided vibrotactile alarms subcutaneously and a pager like device provided auditory and visual alarms Temporal alarm patterns connoted an urgent emergency alarm Call 911 and a less urgent alarm See your doctor In the third clinical study most patients 94 correctly responded to the alarms at 1 3 and 6 months after device implantation Subcutaneous vibrotactile alarms show great potential for use in critical medical applications KEYWORDS medical devices cardiac monitoring vibration perceived urgency medical alarms temporal alarm patterns 4 A cute myocardial infarction is a leading cause of mortality in the United States Annually more than a million people experience a heart attack and more than a third of those die before arriving at a hospital The average symptom to hospital time of almost 3 hours has remained the same for more than a decade despite multiple educational campaigns e g Diercks et al 2010 Gibson 2001 Early warnings and elimination of uncertainty so that people seek immediate medical attention could save many lives and prevent heart damage Medical progress has been unprecedented in the first decade of the current century However communication between medical technology which tracks real time physiological functions and people caregivers and patients remains inadequate Alarms and warnings have long been an important area of investigation for human factors ergonomics specialists Stanton 1994 Research has increased greatly on the use of medical alarms including vibrotactile alarms for medical personnel in operating rooms and intensive care units Edworthy Hellier 2006 Vibrotactile alarms either alone or in combination with visual or auditory alarms are not missed or ignored by medical staff as frequently as are visual or auditory alarms e g Ng Man Fels Dumant Ansermino 2005 Far less research has focused on the use of alarms to warn patients of significant medical events Advancing technology now enables 24 hour monitoring outside the hospital so patients themselves as well as doctors can be warned of significant events Because the alarm might occur at any time an alert provided by an implanted medical device unlike a portable device could be especially beneficial Auditory alarms are currently provided with some implantable cardioverterdefibrillators but research has indicated that many patients do not hear the alarms perhaps because of age related hearing loss or ambient noise Simons Feigenblum Nemirovsky Simons 2009 Subcutaneous vibrotactile alarms could be a viable alternative when used alone or in combination with auditory alarms Alarm design is critical because successful alerting accurate patient identification of alarm type and appropriate patient response can mean the difference between life and death In this article we describe human factors ergonomics work on alarms for a medical device that is designed to alert highrisk cardiac patients about an impending or immediate heart attack Fischell et al 2010 The alarms are multimodal and provide redundant subcutaneous vibrotactile auditory and visual information Here we briefly summarize three studies on the design and validation of subcutaneous vibrotactile patient alarms a a study of alarm temporal patterns and vibrotactile magnitudes b a study of learning and memory for the alarms and c the initial clinical study with patients at high risk of a heart attack DESIGN GOALS FOR THE ANGELMED GUARDIAN The medical device described in this article AngelMed Guardian offers two levels of alarm urgency A high priority alarm Emergency indicates that the patient may be having a heart attack and should call 911 A low priority alarm See Doctor indicates that a condition has been ergonomics in design April 2012 Downloaded from erg sagepub com at HFES Human Factors and Ergonomics Society on April 24 2012 feature This is your heart speaking Call 911 patient is hearing impaired Neither previous research nor standards have provided guidance on the design of temporal vibrotactile alarms PREVIOUS RESEARCH AND GUIDELINES RELEVANT TO ALARM DESIGN In 2004 during the early planning of these studies we could find no information either published or through conversations with experts on the use of subcutaneous temporal vibrotactile patterns for alarms Furthermore although cutaneous vibration was being used as an alarm in cell phones there was little research exploring the use of two or more temporal vibrotactile patterns to signal different alarms We found it encouraging that van Veen and van Erp 2003 noted that people can perceive and describe temporal patterns of vibration although training may be necessary Figure 1 The AngelMed Guardian implanted medical device IMD and external device The basic literature documents that vibra EXD The IMD provides vibrotactile alarms and the EXD provides auditory and visual tion perception varies with age individual alarms The alarms can be silenced after 30 seconds when the patient places the EXD differences and body location Goble over the left chest and presses the EXD s alarm silence button Collins Cholewiak 1996 Stuart Turman Shaw Walsh
View Full Document
Unlocking...