(Press-News.org) TORONTO: Prompt use of an automated external defibrillator, or AED, can greatly increase the survival rates of people who suffer a cardiac arrest. And MIE Professor Tim Chan, working with Dr. Laurie Morrison at St. Michael's Hospital, has developed a formula to determine where best to place these costly but life-saving devices.
In a paper published in Circulation, Chan and Morrison note that publicly registered AEDs in Toronto are not in the best locations to help victims of cardiac arrest. In fact, less than one in four of all cardiac arrests had an AED close by (within 100 metres is the required distance). The average distance to the nearest AED was closer to 300 meters.
Current guidelines suggest areas associated with the highest risk of cardiac arrest should be targeted for AED deployment, after they have been placed in obvious high-traffic areas such as transportation hubs or major sports venues. But it's not clear how to identify these "cardiac hot spots."
Timothy Chan and Morrison looked at the locations of all 1,310 public cardiac arrests in Toronto between December 2005 and July 2010 and the locations of all 1,699 AEDS registered with Toronto Emergency Medical Services.
They found that 304 cardiac arrests occurred within 100 metres of at least one AED (23 per cent).One hundred metres was chosen as the yardstick because it's the approximate distance a bystander could transport an AED in a 1.5-minute walk—the maximum recommended by the American Heart Association.
There were almost three times as many public cardiac arrests in downtown Toronto as the rest of the city – 3.5 per square kilometer per year vs. 0.4 – said Chan. Almost half of all downtown cardiac arrests were near an existing AED compared to only 17 per cent those outside of downtown.
Chan then looked at the 1,006 cardiac arrests that did not take place near an AED. He said that be placing AEDs in the top 30 cardiac arrest "hot spots," they could have covered an additional 112 historical arrests, or 32 per cent. The average distance between a cardiac arrest and an AED would fall to 262 metres from 281 meters.
"Reducing the distance a bystander needs to travel by 20 metres or up to 40 meters in a roundtrip has the potential to save close to half a minute in response time," said Morrison, an emergency medicine specialist who heads Rescu, the largest research team of its kind in Canada dedicated to improving out-of-hospital resuscitation.
"If you have a cardiac arrest, every second counts. Out-of-hospital cardiac arrest kills an estimated 300,000 people in North America annually," she said. "Only five per cent of people who suffer out-of-hospital cardiac arrest survive to be discharged from hospital. The probability of survival decreases up to 10 per cent with each minute of delay between collapse and treatment."
Chan said his mathematical model is more accurate than a population-based model, in which AEDs are placed in areas of densest daytime population.
"Our optimization model should be viewed as a decision-support tool to help prioritize placement of AEDs, make efficient use of public, donor or private funds directed toward public access defibrillator programs, and potentially maximize survival on the basis of geographic patterns of cardiac arrest," said Chan. "Because AEDs are expensive and cannot be placed everywhere, our model allows a decision-maker to quantify the trade-off between the number of AEDS deployed and coverage."
###
About St. Michael's Hospital
St. Michael's Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future health care professionals in more than 23 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, and care of the homeless are among the Hospital's recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Center, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael's Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.
About University of Toronto Engineering
Founded in 1873, U of T Engineering has approximately 5,200 undergraduate students, 1,950 graduate students and 240 faculty members. U of T Engineering is at the fore of innovation in engineering education and research and ranks first in Canada and among the top Engineering schools worldwide.
For more information or to interview, please contact:
Leslie Shepherd
Manager, Media Strategy
Phone: 416-864-6094
shepherdl@smh.ca
St. Michael's Hospital
Inspired Care. Inspiring Science.
http://www.stmichaelshospital.com
Follow us on Twitter: http://www.twitter.com/stmikeshospital
Terry Lavender
Communications & Media Relations Strategist
Faculty of Applied Science & Engineering, University of Toronto
http://www.engineering.utoronto.ca
@UofTEng_Media END
Researchers determine where best to place defibrillators
2013-05-02
ELSE PRESS RELEASES FROM THIS DATE:
NIST demonstrates transfer of ultraprecise time signals over a wireless optical channel
2013-05-02
By bouncing eye-safe laser pulses off a mirror on a hillside, researchers at the National Institute of Standards and Technology (NIST) have transferred ultraprecise time signals through open air with unprecedented precision equivalent to the "ticking" of the world's best next-generation atomic clocks.
Described in Nature Photonics,* the demonstration shows how next-generation atomic clocks at different locations could be linked wirelessly to improve geodesy (altitude mapping), distribution of time and frequency information, satellite navigation, radar arrays and other ...
Health defects found in fish exposed to Deepwater Horizon oil spill
2013-05-02
Three years after the Deepwater Horizon oil spill in the Gulf of Mexico, crude oil toxicity continues to sicken a sentinel Gulf Coast fish species, according to new findings from a research team that includes a University of California, Davis, scientist.
With researchers from Louisiana and South Carolina, the scientists found that Gulf killifish embryos exposed to sediments from oiled locations show developmental abnormalities, including heart defects, delayed hatching and reduced hatching success. The killifish is an environmental indicator species, or a "canary in the ...
Wide-eyed fear expressions may help us -- and others -- to locate threats
2013-05-02
Wide-eyed expressions that typically signal fear may enlarge our visual field and mutually enhance others' ability to locate threats, according to new research published in Psychological Science, a journal of the Association for Psychological Science.
The research, conducted by psychology graduate student Daniel Lee of the University of Toronto with advisor Adam Anderson, suggests that wide-eyed expressions of fear are functional in ways that directly benefit both the person who makes the expression and the person who observes it.
The findings show that widened eyes ...
Use of laser light yields versatile manipulation of a quantum bit
2013-05-02
(Santa Barbara, Calif.) –– By using light, researchers at UC Santa Barbara have manipulated the quantum state of a single atomic-sized defect in diamond –– the nitrogen-vacancy center –– in a method that not only allows for more unified control than conventional processes, but is more versatile, and opens up the possibility of exploring new solid-state quantum systems. Their results are published in the latest edition of the Proceedings of the National Academy of the Sciences.
"In contrast to conventional electronics, we developed an all-optical scheme for controlling ...
Fire in Cape Cod
2013-05-02
According to the Cape Cod Times of April 30, 2013: "The Massachusetts Army National Guard's Natural Resource Program is conducting a prescribed burn at the Upper Cape base. The burn will be held in partnership with federal, state and non-profit agencies. The objective of the burn is to reduce the risk of wildfire by eliminating the heavy buildup of dead wood and debris that can act as fuel. Prescribed burns also manage the habitat for endangered and rare species on the 22,000 acre base. Local fire departments receive training during the prescribed burns. The fire, on a ...
Shaking things up: NIST researchers propose new old way to purify carbon nanotubes
2013-05-02
An old, somewhat passé, trick used to purify protein samples based on their affinity for water has found new fans at the National Institute of Standards and Technology (NIST), where materials scientists are using it to divvy up solutions of carbon nanotubes, separating the metallic nanotubes from semiconductors. They say it's a fast, easy and cheap way to produce high-purity samples of carbon nanotubes for use in nanoscale electronics and many other applications.*
Carbon nanotubes are formed from rolled-up sheets of carbon atoms arranged in a hexagonal pattern resembling ...
New molecule heralds hope for muscular dystrophy treatment
2013-05-02
CHAMPAIGN, lll. — There's hope for patients with myotonic dystrophy. A new small molecule developed by researchers at the University of Illinois has been shown to break up the protein-RNA clusters that cause the disease in living human cells, an important first step toward developing a pharmaceutical treatment for the as-yet untreatable disease.
Steven C. Zimmerman, the Roger Adams Professor of Chemistry at the U. of I., led the group in developing and demonstrating the compound. The National Institutes of Health supported the work published in the journal ACS Chemical ...
NASA sees Cyclone Zane bearing down on Queensland, Australia
2013-05-02
NASA's Aqua satellite captured an image of Cyclone Zane headed toward the northern Cape York Peninsula of Queensland where it is expected to make landfall by May 2 and cross into the Gulf of Carpentaria.
A cyclone Warning is in effect for coastal areas from Mapoon to Cape York to Cape Flattery.
NASA's Aqua satellite passed over Zane on May 1 at 04:05 UTC (12:05 a.m. EDT) and the Moderate Resolution Imaging Spectroradiometer instrument captured a visible image of the cyclone. Zane's most powerful thunderstorms continue to be around the low-level circulation center, ...
New NIST measurement tool is on target for the fast-growing MEMS industry
2013-05-02
As markets for miniature, hybrid machines known as MEMS grow and diversify, the National Institute of Standards and Technology (NIST) has introduced a long-awaited measurement tool that will help growing numbers of device designers, manufacturers and customers to see eye to eye on eight dimensional and material property measurements that are key to device performance.
The NIST-developed test chips (Reference Materials 8096 and 8097) are quality assurance tools that enable accurate, reliable comparisons of measurements on MEMS (MicroElectroMechanical Systems) devices made ...
Self-collection of samples for HPV testing shows promise in detection of cervical cancer in Kenya
2013-05-02
CHAPEL HILL, N.C. – In Kenya, women face a cervical cancer mortality rate that is approximately 10 times as high as in the United States. A study by researchers at the University of North Carolina at Chapel Hill suggests that training women to self-collect genital samples to test for human papillomavirus (HPV), the causative agent of cervical cancer, can increase the coverage rates of cervical cancer screening. Higher screening coverage helps increase rates of detection of cervical lesions and ultimately treatment of the disease.
"The high mortality rate in Kenya is ...