Category Archives: Defibrillation

Every wondered how an ICD (or implantable cardioverter defibrillator) works?

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Implantable cardioverter defibrillator (ICD)

An ICD (or implantable cardioverter defibrillator) is a small device which can be used to treat people with dangerously abnormal heart rhythms.

Abnormal heart rhythms (or arrhythmias) can cause your heart to beat too quickly, too slowly or in an irregular pattern. These heart rhythms can happen suddenly and unexpectedly and sometimes people die as a result.

The ICD is inserted just under your collar bone. It looks similar to a pacemaker and is a little bigger than a matchbox. It is made up of:

a pulse generator – a battery powered electronic circuitone or more electrode leads which are placed into your heart through a vein

An ICD can give your heart electric pulses or shocks to get your heart rhythm back to normal.

How does an ICD work?

Your ICD constantly monitors your heart rhythm through the electrodes and if it notices a dangerous heart rhythm it can deliver three treatments:

Pacing – a series of low-voltage electrical impulses at a fast rate to correct the heart rhythmCardioversion – one or more small electric shocks to try and restore the heart to a normal rhythmDefibrillation – one or more larger electric shocks to try and restore the heart to a normal rhythm

Who needs an ICD?

ICDs are used for some of the people who:

have already had a life threatening abnormal heart rhythm and are at risk of having it again
haven’t had a life threatening heart rhythm, but who have had tests that show they are at risk of one in the future. This is usually because they have inherited certain faulty genes and may have a condition such as Cardiomyopathy, Long QT syndrome or Brugada Syndromehave another type of heart condition, such as heart failure, and who have had, or at risk of having a life-threatening abnormal heart rhythm have had other treatments to correct their heart rhythm which have been unsuccessful.

How is an ICD fitted?

ICDs are inserted under local anaesthetic, but with sedation, so you will feel very sleepy. It can take as little as one hour to insert the ICD, although the time it takes will depend on the type of device you’re having. You will usually stay overnight in hospital and your ICD will be checked thoroughly before you leave.

Who can I talk to?

It’s natural to feel worried about having an ICD fitted, but it often helps to talk about your feelings with someone close to you or with a healthcare professional.
See on www.bhf.org.uk

Understanding Sudden Cardiac Arrest

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Sudden cardiac arrest is often confused with a heart attack. Although a prior heart attack increases one’s risk for sudden cardiac arrest, the two are quite different, with distinct risk factors, treatment options and outcomes.

Anatomy of a Heart Attack

A circulation problem of the heart causes a heart attack when one or more of the arteries delivering blood to the heart are blocked. Oxygen in the blood cannot reach the heart muscle, and the heart muscle becomes damaged. You can think of a heart attack as a “plumbing problem” in the heart.

This damage to the heart muscle can lead to disturbances of the heart’s electrical system. And a malfunction of the heart’s electrical system may cause dangerously fast heart rhythms that can lead to sudden cardiac arrest.

Anatomy of Sudden Cardiac Arrest

In contrast to a heart attack, sudden cardiac arrest is caused by an “electrical problem” in the heart. It occurs when the heart’s lower chambers (ventricles) suddenly develop a rapid, irregular rhythm (ventricular fibrillation) causing the ventricles to quiver rather than contract. The chaotic quivering motion of the ventricles renders the heart an ineffective pump that can no longer supply the body and brain with oxygen.

Within seconds, the person loses consciousness and has no pulse. Only immediate emergency treatment, such as cardiopulmonary resuscitation (CPR) and external defibrillation, can prevent death from sudden cardiac arrest. Time is key to surviving sudden cardiac arrest, with chances of survival decreasing about 10 percent every minute without defibrillation. The American Heart Association recommends defibrillation within five minutes of collapse or sooner.
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Is Hands On Defibrillation Safe (giving CPR during defibrillation)?

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One of the important aspects of advanced life support is minimisation of the interruptions to CPR.
Hands on defibrillation has been suggested as being a safe means of achieving this, however Sullivan (2012) suggests that this may not be as safe as expected.
4 different types of gloves were tested (chloroprene, latex, nitrile and vinyl) with 2 current levels being passed through them (0.1 mA and 10 mA). 45% of single gloves and 77% of double gloves allowed current flow of 0.1 mA within the normal defibrillation voltage range. 7.5% of single gloves and 6.2% of double gloves allowed current flow over 10 mA.
A significant proportion of all gloves tested showed current flow across them, and even if no sensation was felt, it does not guarentee a safety margin.
Take home message – Hands on defibrillation is not entirely safe, so it’s back to minimisation rather than elimination of the pause for defibrillation.

See on emergencyeducation.net

London Ambulance Service – Parliament receives lifesaving equipment

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Visitors and employees at the Houses of Parliament can now be assured of receiving the very best in service from the first aid team, following the installation of 16 new defibrillators.

Part funded by the British Heart Foundation, defibrillators are machines that can deliver a shock to restart a patient’s heart should they suffer a cardiac arrest – when the heart stops pumping blood around the body.

The newly qualified six-strong HeartStart training team and the current first aid team at the Houses of Parliament will now be on hand to deliver this lifesaving care 24 hours a day.

London Ambulance Service is responsible for over 800 public-access defibrillators around the capital, placed in tourist attractions, transport hubs, shopping centres and sports facilities.

Last year the scheme helped to save 11 patients who had suffered a cardiac arrest to be discharged from hospital. Overall in London, almost a third of patients suffering cardiac arrest survived in 2011/12 – the highest in the country.

 
See on www.londonambulance.nhs.uk

Stafford Borough Council – Man speaks of night NOT to remember

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A Stone man has now spoken of the night he nearly died at his local gym.

Russell Follows said if it hadn’t been for a quick thinking fitness instructor he wouldn’t be alive today.

Mr Follows suffered a cardiac arrest in the changing rooms of the borough council run Westbridge Park Fitness Centre. But local instructor, Lee Nicklin used CPR and an on-site defibrillator to keep the man alive until an ambulance took him to University of North Staffs hospital.

Speaking about the incident Mr Follows, 55, said: “Thanks to Lee I’m still here and in the world.”

Stafford Borough Council provides defibrillators at a number of its premises including all leisure centres, the Civic Centre, Gatehouse Theatre and the crematorium on Tixall Road with around 70 members of staff trained to use them.

Mr Follows continued: “I’m coming to terms with what’s happened. I can’t remember anything from that night, not even driving to the gym, or using the gym.”

“He acted immediately and did enough that evening to save my life and I can only say a million thank yous. And even that’s not enough. He is a genuinely nice guy, and got very emotional when I went in and thanked him last week.”

Mr Follows said how defibrillators are a much needed piece of equipment: “I’m just grateful that as well as Lee there was a defibrillator on hand which is there for everyone to use in emergencies – and as you can see they save lives.”

But the incident has not put him off using the gym: “I enjoy the gym so it’s hard not to go, but I’ve been told to take it easy. So I’m not going to over do it just yet.”

Mr Follows left hospital on Saturday 2 March after under going surgery where he was fitted with a mini defibrillator, following the cardiac arrest last month: “Having the defibrillator fitted was a big decision to make, but really it’s a no brainer it’s like a comfort blanket in case anything happens again. Plus it’s also peace of mind for my family.”

Lee, 39 said: “It was all part of the job. We are trained to use the defibrillators and knowing that it saved Russell’s life demonstrates how important the machine and our regular training is.”

He continued: “It was just so emotional and great to see Russell when he came back into the gym with a thank you card.”

Councillor Mike Smith, cabinet member for leisure, said: “We had a similar incident happen in Stafford several years ago, and it just highlights how important defibrillators are.”
See on www.staffordbc.gov.uk

Understanding Defibrillators (AEDs)

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A defibrillator is a life saving device that issues a electrical shock to the heart in some cases of cardiac arrest. This process is called defibrillation and can help save lives. Cardiac arrest happens when the heart stops pumping bloody around the body. At this time it is critical that defibrillation happens as soon as possible.

This electrical shock depolarizes a critical mass of the heart muscle, terminates the arrhythmia, and allows the natural rhythm  of the heart to be re-established by the body’s organic pacemaker, in the sinoatrial node of the heart.

According to the British heart foundation for every minute that a patient is not giving defibrillation their chances of survival decrease by 14 per cent. In fact research also show that’s providing a shock within five minutes of the patient collapsing provide the best chance of survival.

Defibrillators can come in many forms and sizes. These can be external, transvenous, or implanted. This will all depend on the device used. The most common devices are called automated external defibrillators (AEDs) and because they automate the defibrillation process, by automation of the treatable rhythms, meaning that bystanders or people with very little or no training at all can use them.

Because of the importance of the defibrillators and the low numbers available, it is vital that these devices are strategically placed within an area. These are often placed where an ambulance would find it difficult to get to –  i.e.,  placed with traffic congestion, poor infrastructure, or where large crowds gather.

Defibrillation was first successfully performed in 1899 by two physiologists in Switzerland. It was found that small electrical shocks could induce ventricular fibrillation in dogs. However, it wasn’t until 1933 that a serious alternative to injecting powerful drugs straight to the heart. Dr Albert Hyman came up with the invention of a hollow needle, an insulated wire to the heart to deliver the electrical shocks.

These days Defibrillators have come a long way from the Hyman days. In order to use the AED, the machine is turned on and then a voice prompt will instruct the rescuer on what to do. The voice prompts the rescuer to place the pads into position on the chest and these then detect if a shock is needed by reading activity in the heart.

Defibrillation should never be seen as an alternative to to CPR, which can help buy time before defibrillation is needed. The British Heart Foundation state that if more GP surgeries were equipped with defibrillators that survival could be increased by up to 60 per cent if the patient is treated immediately after entering cardiac arrest.

AED’s are often placed in highly visible areas and it is not recommended that these should be placed in locked or code restricted cabinets as this makes them inaccessible in time of emergency where the time taken is of essence. AED’s are often brightly coloured, and are often encased in protective cases. When these protective cases are opened nearby staff are alerted by a buzzer.

 
See on www.blog4safety.com

Automated External Defibrillators and the Urban myths

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Sudden Cardiac Arrest (SCA) is a life-threatening condition that must be treated within minutes if the victim is to survive. The only therapy which can treat the life-threatening arrhythmia that occur during SCA is defibrillation; the earlier the better. Various studies have determined that for every minute defibrillation is delayed survival falls rapidly. In one study it was determined that this fall in survival was around 7 to 10% while the British Heart Foundation (BHF) have concluded that the fall in survival percentage is 14%.

Defibrillation for the SCA victim needs to be part of the ‘pattern of care’; a well-establish process – the Chain of Survival – assists the rescuer in giving the victim the best chance of survival; call for help, early CPR, early defibrillation and advanced life support.

Automated External Defibrillators (AEDS) are designed specifically to enable non-medical rescuers to treat SCA victims as they are safe, easy to use and effective.

There are, however,  a number of myths and mis-information around the whole issue of SCA and the use of an AED.

Lay persons are often confused between a heart attack and a sudden cardiac arrest. These are two separate medical conditions and although the first can lead to the second, an AED is designed to treat the unresponsive, not breathing victim the indications for SCA and the use of an AED.

Clinically, defibrillation does not ‘jump’ start the heart. Delivery of a biphasic electrical current depolarises the heart cells allowing the organ’s natural ‘pacemaker cells’ to re-start and the heart to return to normal electrical activity or sinus rhythm. During SCA the heart is exhibiting ventricular fibrillation (VF) ; a chaotic discharge of electrical current that prevents oxygenated blood from circulating or pulseless ventricular tachycardia (VT) which while more regular is still too fast to again allow the effective circulation of blood thus denying the brain of oxygen.

People often ask about the ‘danger’ of rescuers or bystanders receiving a shock if they are touching the victim of SCA during defibrillation. While we have adopted the historical warning ‘stand clear’ from the use of manual defibrillators, studies show that current leakage from a defibrillation device using adhesive pads is actually minimal. The majority of current delivered being discharged into the chest and heart. The actual amount of current leakage recorded in one study measured this as well below 2,500 microamps, the international standard relating to this threshold. To put this into layman’s terms this equates to the current from a standard nine volt battery. The European Resuscitation Council (ERC) Guidelines (2010) describes 29 instances of death or harm from a manual defibrillator, however this is a different type of device, produced for professional rescuers, utilising metal paddles (although some are available with adhesive defibrillation pads.

All in all, AEDs are safe, effective and easy to use so why would you not want to place these in your workplace or public area?
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