Study Looks to Predict Sudden Cardiac Arrest Risk

A promising new way to predict sudden cardiac arrest risk has been identified by medical researchers at the University of Buffalo.

For patients who are at the highest risk of sudden cardiac arrest, this is exciting news, as this research may give cardiologists an advanced screening tool to help those in the high-risk category and those most likely to benefit from receiving an implantable cardiac defibrillator (ICD).

ICDs are mainly used to prevent sudden cardiac arrest in patients with advanced heart disease, but many patients’ devices are never triggered.

New research suggests that imaging the degradation of nerve function in the heart may identify those patients at greatest risk of developing a life-threatening heart rhythm.

Using Positron Emission Tomography (PET), in the largest PET imaging study ever done on sudden cardiac arrest, researchers were able to measure the amount of nerve damage within the muscular tissue of the heart.

PET imaging is also able to show where nerves have died or become damaged due to inadequate blood flow.

“The principal question we posed with this study was whether the amount of nerve damage in the heart could predict sudden cardiac arrest,” says James A. Fallavollita, author on the study. “We found that when at least 38 percent of the heart was showed signs of nerve damage, there was a significant increase in the risk of sudden cardiac arrest.”

At this time, to determine whether an ICD is needed, doctors take a measurement of heart function called the ejection fraction; the percentage of blood pumped by the heart with each beat. An ejection fraction of 35 percent or less is a strong indicator of sudden cardiac arrest risk; these patients usually require an ICD.

This research is a prime example of translational medicine (the emerging field which focuses on using what is learned in pre-clinical studies to do smarter things in the clinic). In this case, the pre-clinical studies demonstrated that the risk of developing ventricular fibrillation (a deadly heart rhythm) was related to regional nerve damage.

“Ultimately, we wanted to develop an approach that could tackle the problem of identifying a larger portion of the patients with coronary artery disease who are at risk of developing sudden cardiac arrest,” explains John M. Canty, a principal investigator of the research. “Since many patients who suffer a cardiac arrest do not have severely depressed heart function, PET imaging may be able to identify high risk individuals who, in the future, could be considered candidates for an ICD.”

Update – BC Influenza Control Policy

Earlier in the year, health authorities throughout BC (on the advice of Dr. Perry Kendall, BC’s Provincial Health Officer) agreed to ramp up efforts to protect patients and seniors from influenza exposure this flu season (read the full story). Now, after a much heated debate, the government has temporarily backed away from the controversial plan to force thousands of provincial health workers to get a flu shot before they can work with patients. 

Original Influenza Policy:

Effective December 1, 2012, all staff, physicians, students, volunteers, contractors and vendors must either be immunized against the flu or wear a procedure mask while in patient care areas.

Updated Influenza Policy (Dec 5th):

The Ministry of Health decided that during the first year of flu policy implementation the focus will not be on enforcement. Health authorities will not be disciplining employees, but will focus on education and awareness to promote compliance with the new policy.

Unimmunized staff must still wear masks in patient care areas, and immunized staff must display the flu shot sticker on ID badges during flu season.

From our Medical Director Dr. Allan Holmes:

“The following Influenza Control Policy for the Health Authorities remains in effect. The only change is that the enforcement within the Health Authorities will not be a focus in the first year. I remain support of the policy as it is designed to maximize protection for our patients.”

Learn more about influenza:
http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/diseases-maladies/flu-grippe-eng.php

WHO Novel Coronavirus Infection – Update

As a leader in risk management and emergency preparedness services, we would like provide an update from the BC Centre for Disease Control and the World Health Organization regarding further detections of the novel coronavirus originally posted by the WHO  in September, 2012. 

What’s New

Four additional confirmed cases of the novel coronavirus identified.

• Three in Saudi Arabia (including one death)
• One in Qatar

The Qatar case had onset of severe respiratory symptoms in October, recovered and was released from care in November. Onset dates for the recent Saudi Arabia cases are not yet available.

To date, this brings the total number of laboratory confirmed cases to six.

• Two cases fatal
• All linked either to Saudi Arabia or Qatar

Of the four most recently confirmed cases, two are from the same family in Saudi Arabia and represent the first epidemiologically-linked cases.

One of these died and the other has recovered. In addition, two other members of the same family presented with similar symptoms of which one also died and one is recovering.

It has yet to be determined whether this family cluster signifies human-to-human transmission or rather shared exposure to a common animal (i.e. bat) source. Investigations are underway.

What’s Advised

The WHO advises that until more information is available; consider the novel coronavirus virus likely to be more broadly distributed than Saudi Arabia and Qatar.

Information on the full clinical presentation is only available for the first two cases reported in September 2012.

In the absence of other details or guidance, clinicians may reasonably consider novel coronavirus testing for patients presenting with signs or symptoms of severe acute respiratory infection (SARI), particularly in the absence of other explanation.

Worldwide Acute Respiratory Infections

Any clusters of SARI or SARI in health care workers should be thoroughly investigated regardless of where they occur.

Where this novel coronavirus is considered, the local health unit and/or Medical Health Officer should be immediately notified and guidance sought.

Patients should be managed in strict respiratory isolation including contact and droplet precautions.

The message from the WHO is not to panic but rather to  ask countries to be more vigilant.

WHO Update – November 23

The most recent WHO update is available at the following link:
http://www.who.int/csr/don/2012_11_23/en/index.html

How ETCO2 may inform vasopressor use!

Consider the following scenario. While in the emergency department a man suffers a witnessed cardiac arrest, for which he receives prompt high quality CPR, 200 joules defibrillation for an initial rhythm of V-Tach. The defibrillation is followed by a further 2 minute round of high quality CPR during which time an advanced airway with minimal interruptions in chest compressions. ETCO2 monitoring is initiated and shows 12mm/Hg. From this resuscitators can see that patient remains without pulmonary circulation and that the quality of CPR is satisfactory. After the 2 minutes, a quick pause in CPR reveals persistent V-Tach on the monitor. Chest compressions are resumed while the defibrillator is charged, the patient is cleared, 200 joules are delivered chest compressions are immediately resumed.

Let’s now consider two different paths that the scenario can take from here:

• The defibrillation is unsuccessful, and during the 2 minutes of high quality CPR that follow the ETCO2 hovers around 7 mm/Hg. Seeing this low number, the team changes chest compression providers, and a new clinician is able to get the waveform up to 12mm/Hg. In this case, there is no ETCO2 indication of return of spontaneous circulation, and since there remain no signs of life, CPR is continued and as the code progresses the clinicians consider giving IV epinephrine.

• Alternatively, the defibrillation is successful, and during the 2 minutes of high quality CPR that follow the ETCO2 jumps to 40mm/Hg. In this case there is ETCO2 indication of return of spontaneous circulation, and the team searches for other signs of life, which may include a pulse. Finding none: high quality CPR is continued however this time the decision is made to withhold the IV epinephrine.

The above scenario illustrates how continuous ETCO2 can not only serve to confirm ongoing placement of advanced airways, but can also be used to inform the quality of CPR, illuminate ROSC and help guide vasopressor use during resuscitation attempts. This being said there still remains no evidence that using epinephrine in this way contributes to neurological intact survival to hospital discharge.

Lastly, this practice of ETCO2 monitoring during resuscitation attempts relies on placement of advanced airways, which have been deemphasized in the ACLS Guidelines since 2005. As such we can see how with increased emphasis on ETCO2, the latest Guidelines may result in an increased use of advanced airways. This unto itself is not necessarily a bad thing, as long as we do not do so to the detriment of our patients. When using advanced airways there is an increase in responsibility to not interrupting chest compressions for too long, and to avoid the hyperventilation of our patients with tidal volumes that are too large and ventilation rates that are too excessive.

Darin Abbey RN
Clinical Nurse Educator
Emergency Department
Nanaimo Regional General Hospital

First Aid Training Dangerously Low

A new poll conducted for the Red Cross reveals that Canadians are unprepared to perform first aid in a medical emergency.

The Good News

The majority of Canadians feel will recognize the signs of a life-threatening health emergency such as Choking, Heart Attack or Cardiac Emergency, Heat Emergency, Anaphylactic Shock and Concussion.

The Bad News

While nearly 98 percent of Canadians say knowing how to perform first aid is important, 82 percent did not take a first aid course within the last three years.

It is not enough to recognize the signs of a medical emergency; we need to be able to act.

Currently, only a small portion (18 percent) of Canadians has their first aid certification and many believe they do not possess the skills needed to save lives when an emergency happens.

 “Although 68 percent of Canadians say they can recognize the signs of a life-threatening health emergency, like choking or cardiac arrest, less than half believe they have the skills to provide life-saving basic first aid,” summarizes Don Marentette, national manager of first aid programs with the Canadian Red Cross.

“The Red Cross believes lapsed training and Canadians’ low confidence in their ability to save a life are directly related, and pose a risk in emergencies.”

Nearly 40 percent of Canadians reported they have had to perform first aid in an emergency situation. In 22 percent of these cases, first aid was performed on a family member.

Even though Canadians are more likely to use first aid skills to save the life of a loved one than anyone else, there is a significant gap between Canadians’ perception of the importance of taking a first aid course, and actually taking one.

For more information, please see the Red Cross Polling Information

With the high likelihood that we will all have to perform CPR on a loved one at some point during our lives, we should all be taking the necessary steps to be prepared.

As a leader in the development of medical education workshops, Global Medical Services is committed to the training of Canadians in CPR and AED use.

If you would like to become trained in first aid, please see our current offerings:

2012 Course Offerings

The Darker Side of the Sun

What is heat stroke?

Heat stroke is a form of hyperthermia (abnormally raised body temperature) accompanied by changes in nervous system functions.

Heat stroke should not be confused with heat cramps or heat exhaustion, less severe forms of hyperthermia. Heat stroke is defined by a body temperature of at least 104F (40C). It should be treated as a medical emergency and is often fatal if not treated promptly.

In normal circumstances the body is able to dissipate heat through the skin or by the evaporation of sweat. However, in extreme heat, high humidity, or during vigorous physical exertion under the sun, the body may not be able to dissipate the heat quickly enough, leading to a rise in body temperature.

Heat stroke can also be caused by dehydration. When an individual becomes dehydrated they may not be able to produce enough sweat to dissipate the heat.

Although a heat stroke can affect anyone, some are at a higher risk than others, including: infants, the elderly, athletes and individuals who work outside and exert themselves under the sun.

Symptoms

Heat stroke can vary from case to case, but often an individual will experience the symptoms of heat exhaustion such as nausea and vomiting before progressing to heat stroke. However, in some cases heat stroke can develop rapidly without warning and mimic the symptoms of a heart attack. Common symptoms of heat stroke include:

• Rapid pulse
• High body temperature
• Absence of sweating
• Difficulty breathing 
• Strange behavior
• Hallucinations
• Confusion
• Agitation
• Disorientation
• Seizure
• Coma

Treatment

Victims of heat stroke must receive immediate cooling treatment to avoid permanent organ damage. It is important to get the victim to a shady area, remove clothing, apply cool or tepid water to the skin and if available, place ice packs under armpits and groin. If the person is able to drink liquids, have them drink cool water or other cool beverages that do not contain alcohol or caffeine. Lastly, monitor body temperature with a thermometer and continue cooling efforts until the body temperature drops to 101F (38C).

The best prevention measures for heat stroke are to avoid becoming dehydrated and to avoid strenuous physical activity in the hot and humid weather. Wearing hats and light-coloured, lightweight, loose clothes will help keep the body’s temperature balanced. If physical activity cannot be avoided, drinking plenty of fluids such as water and sports drinks will help. After the prolonged activity in the sun, the body will need a replenishment of electrolytes; sodium is a great source. An electrolyte imbalance can directly lead to one or more of the symptoms above.

Warfarin or Warfar-out?

Warfarin or Warfar-out?: new stroke recommendations from American Heart Association and American Stroke Association.

The AHA/ASA has released recommendations on the use of the new oral antithrombotic agents to prevent stroke in patients with nonvalvular atrial fibrillation.

Head on over to the theheart.org for an article which summarizes the advisory published in Stroke on August 2, 2012.

The Structure of Warfarin (Anticoagulant)

The relevance of this article is health care professionals will have more choices in oral anticoagulants and more patients will receive treatment.

The novel drugs are reportedly safer and do not require point-of-care blood tests to monitor INR values. All of this should hopefully add up to better stroke prevention in patients with nonvalvular afib.

I welcome your thoughts and comments.

Another Look at Chest Compressions

In 2010, international guidelines for cardiopulmonary resuscitation (CPR) recommended a change in compression depth. The minimum depth was raised from 38 to 50mm, although there was limited data to support the change from the 2005 guidelines.

Recently, the Resuscitation Outcomes Consortium (ROC) conducted a large scale study to examine patterns of CPR compression depth and associated survival rates.

The trial included 1,029 cases from 7 different sites across Canada and United States. The cases were typical of most cardiac events that take place out of a hospital; meaning 13 percent were in a public location and 40 percent were witnessed by a bystander.

The study was able to determine an average chest compression depth of 37.3mm, slightly less than recommended 2005 guidelines of 38mm and quite short of the new 50mm standard.

According to the study, half the patients received less than the 2005 guidelines and 90 percent received less than the 2010 guidelines; revealing a current trend of sub-optimal compression when delivering First Aid.

To lend credence to the “ sub-optimal trend,” the study has found a strong connection between survival and the increase in chest compression depth from 38 to 50mm.

Although compression depth continues to play an important role in CPR, the most effective depth is still unknown. The ROC found no evidence to prove or disprove the new recommendations at depths greater than 50mm.

During the study, the ROC also found an increased rate of chest compressions negated the positive effects of an increased depth. The recommend rate is 100 compressions per minute. Researchers suggest rescuers be cautious not to exceed a compression rate of 120.

The bottom line is that we don’t push hard enough on the chest. In order to increase survival rates, we need to deliver high-quality CPR. High-quality CPR must consist of proper compressions in both depth and rate; constraints rescuers need to be aware of.

 

 

Shins and Needles

I came across this discussion point while perusing the medical blog world. The discussion revolves around the difficulties with pediatric Intra-Osseous needle placement and more so, keeping the needle in the bone.

Most of my experience with IO insertion and care has been on adults and rarely, actually never, have I witnessed an IO cannula dislodge or come out of an adult limb without the application of brute force. I understand this is not the case for children.

Intraosseous pediatric trainer

See this link for discussion about how best to secure an IO in pediatric patients. 

http://emcrit.org/misc/how-to-secure-an-io-in-a-peds-patient/

Take home message; if you need to insert an IO, you need to make sure it stays in.

FYI: “cannula” is Latin for little reed

Intra-Osseous in action:

All About Airway… pt. 2

This week I am highlighting two airway discussion points which have recently come to my attention: cuffed vs. non-cuffed endotracheal tubes (ETTs) in pediatric patients and the possible, negative side effects of supraglottic airways.

See my first post on cuffed vs. non-cuffed endotracheal tubes: Part 1

Supraglottic Airways: Help or Harm?

Health Care Providers (HCPs), working in multi-disciplinary, team oriented environments, are able to achieve rapid and early airway management without interrupting resuscitation efforts. However, the role of ETTs has been de-emphasized during cardiac arrest management and HCPs are encouraged to use alternate airway devices, such as supraglottic airways.

Supraglottic airways minimize interruptions in compressions and as a result, maximal blood flow to the brain. Or, so we thought…

A recent swine study shows evidence supraglottic devices may decrease cerebral blood flow in low output states. See the article below.

http://emcrit.org/wee/extraglottic-airways-harmful-cardiac-arrest/

In the ACLS courses I instruct at Global Medical Services, I have been strongly encouraging the use of supraglottic airway devices.  Mainly because King Tubes or laryngeal mask airways can be inserted without stopping chest compressions and this allows for more blood to the brain. But, if these airway devices impede blood flow to the brain, should we be using them at all?

What is the future of airway management during cardiac arrests? Will newer, high-tech devices make it to market or will airway management go back to a head-tilt, chin-lift with oxygen from a simple mask?

I’d love to hear your thoughts and opinions. Let me know what you think about these discussion points.