Pacemakers: some of the risks and complications you are not warned about.
Abstract: Pacemaker technology has advanced rapidly over the last decade. A lot of everyday interference can be regarded as transient. The media tend to cover stories of relatively insignificant transient interference incurred by pacemaker wearers while many manuals gloss over the high risks, some potentially life-threatening. These include the reliability of pacemakers and the use of monopolar diathermy which can generate electromagnetic interference, potentially causing a pacemaker to malfunction.

KEYWORDS Electronic interference / Harmonic scalpel / Monopolar diathermy / Pacemaker / Transient interference
Author: Marsh, Ann
Pub Date: 10/01/2008
Publication: Name: Journal of Perioperative Practice Publisher: Association for Perioperative Practice Audience: Academic Format: Magazine/Journal Subject: Health; Health care industry Copyright: COPYRIGHT 2008 Association for Perioperative Practice ISSN: 1750-4589
Issue: Date: Oct, 2008 Source Volume: 18 Source Issue: 10
Accession Number: 200343270
Full Text: Introduction

There are approximately 18,000 new pacemakers implanted each year in the UK (Senthuran et al 2002). Most pacemakers are implanted to correct bradycardia (slow heart beat) due to sinus node disease or atrioventricular block. The recipients of the pacemakers are generally elderly people with an average age of 75 years for a first implant (Allen 2006). Booklets from the British Heart Foundation (2005) give the new pacemaker recipient very positive advice about pacemakers in general, but they appear to gloss over, or ignore, some of the risks and complications associated with having a pacemaker.

The media would have us believe that some electrical equipment encountered on a daily basis may cause serious problems, but this can be regarded as transient interference and as soon as the pacemaker wearer walks away from the source of the interference the pacemaker will work correctly. Some of the more serious risks to the pacemaker wearer that will be discussed are the reliability of pacemakers and the effect monopolar diathermy may have on a pacemaker during surgery.

Background

Since the 1960s pacemaker technology has advanced greatly. Pacemakers have become smaller, lighter, more comfortable for the wearer and more resistant to electromagnetic interference (EMI). They consist of a battery and electronic circuitry which is contained in a titanium casing. In response to small electrical signals sensed in the patient's heart the pacemaker can deliver a short, low voltage electrical current to the heart muscle. Over 50% of implanted pacemakers are rate-adaptive--where the pacemaker matches the pacing to the activity level of the patient (Allen 2006).

The majority of pacemakers are implanted using a local anaesthetic and situated below the collarbone, between the skin and the chest muscle with one, two or three leads which sit inside the heart. Occasionally they are implanted in the abdomen with a lead attached to the outer surface of the heart (British Heart Foundation 2005). Modern pacemakers work from a lithium iodine battery with a lifespan of six to 10 years. Filters within the software provide a high degree of tolerance to EMI and the pacemaker's titanium casing provides even further protection against its effects (Allen 2006).

Tonks (2006) is very sceptical about the number of pacemakers that are recalled and quotes statistics showing that there are high numbers of pacemakers which are faulty. Tonks is concerned that unreliable reporting does not show pacemakers that break down because of faulty leads, or patients who die because their pacemaker was faulty. The Medicines and Healthcare products Regulatory Agency (MHRA 2008) describe a significant number of Medical Device Alerts issued between 1997 and 2007 appertaining to faulty pacemakers, including many of the leading manufacturers of pacemakers. These vary from microprocessor failure, risk of pacemaker failure, rapid pacing occurring when the device is being switched off and sudden cessation of output. In 2002, the MHRA acknowledged the problem of under-reporting of adverse incidents involving pacemakers and emphasised the need for pacing technicians and clinicians to report adverse incidents to them (MHRA 2002). Fogoros (2003) considers that any faults occurring in a pacemaker usually happen soon after it is implanted and can be detected and rectified before they become serious. Symptoms that might indicate a malfunctioning pacemaker include the patient feeling weak, tired, light-headed, and dizzy or losing consciousness. The patient is advised to contact their doctor.

Pacemaker interference

Shavers, hairdryers and other household tools such as drills have been considered as possible causes of interference to a pacemaker. The American Heart Organisation (2007) says that there is a remote potential for this type of equipment to cause interference and it would only inhibit a single beat. There have been further issues surrounding airport screening systems and anti-theft devices in shops, but the current advice is to move through them quickly and then move away from them. If by chance the pacemaker triggers an alarm the wearer should show his/her registration card received at the time of implantation. Yeo and Berg (2004) recommend that patients with pacemakers walk through metal detector gates at airports rather than be scanned using a held-hand device as they contain a strong magnet that is powerful enough to switch the pacemaker programme to asynchronous mode where the pacemaker paces the heart at a fixed pace.

Interference from mobile phones

The use of mobile phones causing problems with pacemakers has been widely reported. A Medical Device Alert from the MHRA (1996), following a review of European and international studies concluded that interference to a pacemaker could be caused by the transmitted radio frequency signal when the mobile telephone was held close to the pacemaker, or when its antenna was placed in direct contact with the skin. The interference only occurred when the mobile phone was in use or in a standby mode and could take effect by increasing the pacing rate, temporary asynchronous mode or temporary inhibition. The MHRA's advice to pacemaker wearers with mobile phones is to keep the phone more than 15 cm away from the implant. This advice is reiterated by The British Heart Foundation (2005) which also suggests the mobile phone is not kept in a pocket close to the pacemaker site, and to use the ear furthest away when making or receiving calls.

According to the MHRA (2007) the use of personal music players is also considered to be safe if used in a similar manner to a mobile phone.

The British Heart Foundation (2005) advises that arc welding equipment should be avoided as it creates an electromagnetic field which may cause damage to pacemaker circuitry. But any power generating equipment and equipment containing powerful magnets may also affect the pacemaker. This is not very helpful for pacemaker wearers who need to have more specific guidelines.

Diathermy

As many pacemaker wearers are elderly, it is possible that they may require a operation where diathermy may be used for cutting and coagulating tissue. Monopolar diathermy works by the passage of a high frequency current through a patient from an active electrode, for example forceps, to a return electrode, for example, the diathermy pad on the patient. Cutting works when the voltage between the active electrode and the target tissue is so high that the electric arcs ignite creating temperatures above 100[degrees]C and the tissue is either burned or vaporised (ERBE Elektromedizin 2007). However, monopolar diathermy emits radio frequency waves and the leads from the pacemaker act as good receiving antennae (Yeo & Berg 2004). The resulting interference may cause potential permanent damage to the pacemaker that could threaten the patient's life (Smith & Smith 2001). The American Radio Relay League (2002) claims that most problems arise when the energy level of a nearby field is either very high, or its frequency mimics the pacemaker's cardiac range. The majority of patients will be unaware of the potentially serious damage monopolar diathermy can do to their pacemaker, and rely on hospital staff to be knowledgeable about it and protect them.

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Information given to new recipients of pacemakers in the British Heart Foundation's (2005) booklet is vague, saying that some equipment used in surgery can cause problems. It is therefore imperative that the whole team (the nurses conducting the preoperative assessment, ward nurses and the theatre team) involved with the patient's care are aware of the implications at the earliest possible moment, and provide a high standard of practice and care at all times using the best available evidence (NMC 2008). Failure to act in the patient's best interest could result in a negligence claim by the patient if they experience harm. Early identification of a patient with a pacemaker can ensure that appropriate advice can be sought from the patient's cardiologist, or their team, and the appropriate equipment is available for the operation. It may be too late to change equipment or contact the cardiac clinic when the patient has arrived in the anaesthetic room and may result in an operation being cancelled at a very late stage.

EMI and monopolar diathermy

The effects of EMI from diathermy are unpredictable and may manifest as inhibition of pacing (missing a beat for a whole cycle), triggering of asynchronous pacing, reprogramming of software, resetting the device and damage to the pacemaker's circuitry (MHRA 2006). Armstrong and Williams (2007) claim that monopolar diathermy can inject large radio frequency currents directly into the heart of patients with implanted pacemakers. This may prevent the pacemaker from working properly as the currents may damage sensitive tissues and reduce their sensitivity to pacemaker signals. As the patient is on an operating table and unconscious they are unable to move away from the source of the interference or report the effects. Decisions have to be made by the anaesthetist and surgeon with advice from the patient's cardiac follow-up clinic as to whether it is wise to use monopolar diathermy with certain precautions in place, or to use an alternative method of haemostasis.

While most pacemaker manufacturers contra-indicate the use of monopolar diathermy or strongly warn against its use, there may be times when its use cannot be avoided (for example, elective surgery where the surgeon, anaesthetist and cardiac follow-up clinic may consider the advantages of its use outweigh the disadvantages, or in an emergency situation where the benefits outweigh the risks). The clinic can check the patient's cardiac condition and the condition of the pacemaker and its battery. It can also give extra support to the team before, during and after the procedure. Bearing in mind that both Tonks (2006) and MHRA (2008) have expressed concern over the number of faulty pacemakers, this would appear to be good advice. The MHRA (2006) has issued guidelines which include having resuscitation equipment and defibrillators available. Allen (2006) says that external defibrillators generate high amounts of EMI which are likely to damage or re-programme the pacemaker, and the leads will have high energy currents which may burn the patient's myocardium. Allen (2006) also suggests that if defibrillator pads are used they should be placed at least 10 cm away from the pulse generator, possibly placing them in an apex-posterior position.

Further advice from the MHRA (2006) on the use of monopolar diathermy includes the monitoring of the patient carefully and accurately by an anaesthetist who is able to interpret the information given on an ECG, and using an arterial line or pulse oximeter as an alternative method of detecting the patient's pulse. They recommend that any cables attached to the diathermy equipment are away from the site of the implant, the return electrode is anatomically placed so the electrical current passing between the diathermy electrode and the return electrode is as far away from the leads and the pacemaker as is possible. The anaesthetist must inform the surgeon of any signs of pacemaker inhibition so that the diathermy can be used intermittently or discontinued.

The MHRA (2006) does not recommend the placing of a clinical magnet over the implant if there are signs of interference with the pacemaker as the response of clinical magnets placed on modern pacemakers would depend upon the model of the pacemaker and how the device has been programmed and should only be used if the pacemaker follow-up clinic advises this.

Alternatives to monopolar diathermy

There are alternatives to monopolar diathermy. Bipolar diathermy is considered safer than monopolar diathermy as the current pathway is of lower power and shorter. The effect is localised within tissue contained within the two ends of the forceps which act as the active and return electrodes. Bipolar diathermy is limited to coagulation only but is safer because it is not subject to arcing or stray currents. It has less of an impact on pacemakers because the current does not pass through the patient's body, but still may cause damage (ERBE Elektromedizin 2007).

To use diathermy to its full capacity and use it safely, Smith and Smith (2001) consider that any staff using diathermy must understand the history, physics, potential tissue effects and safety concerns of using diathermy. Lack of understanding of the safety concerns is demonstrated by Veitch and Fairclough (1998). A questionnaire sent to 634 gastroenterologists in Britain showed that 77.3% were aware of possible adverse interaction between diathermy and pacemakers, but only 74.2% checked if their patient had an implanted pacemaker and then only 36.2% used ECG monitoring during the procedure. This also demonstrates that almost one quarter of them were unaware of possible problems, albeit a small chance of an adverse interaction, and that many of the respondents ignored the seriousness of using diathermy with an implanted pacemaker.

Another alternative to diathermy is to use a harmonic scalpel which uses ultrasound waves to cut and coagulate tissue. These do not interfere with pacemakers but have several disadvantages. Firstly the high cost of the disposable working element is a major factor. This should not influence a surgeon's decision but as most hospitals are working to tight budgets, the theatre stores may not have many in stock and those available earmarked for other elective surgery. However, the cost of the element could be far less than the cost of replacing a damaged pacemaker with the associated factors of risk to the patient. Secondly, the surgeon may have had inadequate training. Perko et al (2006) outlines that thermal damage is greater if a sustained period of application is applied continuously to tissue and damage is reduced if there is a brief midpoint interruption during application. Without adequate training a surgeon may leave himself open to claims of negligence if a problem occurs.

Safer management of patients with a pacemaker in the operating theatre

* Consider using safer alternatives, for example, bipolar diathermy or a harmonic scalpel.

If alternatives are not available or suitable:

* Ensure the diathermy plate is placed as far away as possible from the pacemaker.

* Keep diathermy cables as far away as possible from the pacemaker.

* Have resuscitation equipment available.

* Do not rely on a clinical magnet to guarantee asynchronous pacing.

Summary

Pacemaker technology is constantly improving. The new generation of pacemakers are becoming even smaller, lighter and have increased protection against EMI. More patients, often elderly people, are receiving the benefits of this technology which improves their quality of life and extends their life span. However, there is a question about the reliability of pacemakers as faults may be seriously under-reported and there is also a problem of using monopolar diathermy during surgery on patients with implanted pacemakers. Information for patients on this issue is often vague and patients rely on healthcare professionals to protect their interests. If the healthcare professionals involved in the patient's surgical care are unaware of the potentially serious consequences of using monopolar diathermy on these patients, then an adverse event which could threaten the patient's life could occur. It is imperative that the appropriate precautions are taken as outlined by the MHRA (2006) along with the advice of the patient's follow-up cardiac clinic to ensure a safe surgical procedure.

Task 1

Review the physiology of the heart and how an implantable permanent pacemaker works.

Reflect on how your new knowledge will impact on the perioperative care you provide to patients.

Notional Learning Hours

1 hour for each task

Knowledge and Skills Dimension

Core 2: Personal and people development

Core 3: Health, safety and security

Core 4: Service improvement

Core 5: Quality

G1: Learning and development

Task 2

Identify the main clinical conditions that require a patient to be paced perioperatively.

Notional Learning Hours

30 minutes

Knowledge and Skills Dimension

Core 2: Personal and people development

Core 3: Health, safety and security

Core 4: Service improvement

Core 5: Quality

HWB6: Assesment and treatment planning

HWB7: Interventions and treatments

Task 3

Explore your department and identify all potential sources of electromechanical interference for a patient who is dependent upon their pacemaker (including the holding bays, anaesthetic room, theatre and recovery rooms).

Notional Learning Hours

30 minutes

Knowledge and Skills Dimension

Core 2: Personal and people development

Core 3: Health, safety and security

Core 4: Service improvement

Core 5: Quality

HWB9: Equipment and devices to meet health and wellbeing needs

HWB10: Products to meet health and wellbeing needs

Task 4

A patient with a pacemaker presents for cardioversion. Describe where you would place the defibrillator pads and why.

Notional Learning Hours

30 minutes

Knowledge and Skills Dimension

Core 2: Personal and people development

Core 3: Health, safety and security

Core 4: Service improvement

Core 5: Quality

HWB6: Assesment and treatment planning

HWB7: Interventions and treatments

Task 5

A patient with a pacemaker is scheduled to undergo shoulder surgery. What precautions should be taken to limit electromechanical interference during the immediate preoperative period (including patient positioning and diathermy return electrode placement).

Notional Learning Hours

1 hour

Knowledge and Skills Dimension

Core 2: Personal and people development

Core 3: Health, safety and security

Core 4: Service improvement

Core 5: Quality

HWB6: Assesment and treatment planning

HWB7: Interventions and treatments

Acknowledgements

Open Learning Tasks for this article were provided by Sherran Milton and Mr Ken Ali, MSc(Card), BSc(MPPM), Testamur NAPSE, MSCST.

Additional Learning Resources

Associated AfPP online modules:

* Patient Care: Knowing and Doing

* The Multi-disciplinary Team in the Operating Theatre

* Communication Skills

* Patient Care in the Operating Department

* Organisational Skills and Tools

* Electrosurgery in Perioperative Practice

* Liability and Accountability

* Care and Responsibility

* Consent

* The Human Rights Act

Web links and key documents

Medtronic: www.medtronic.co.uk/UK/

St Jude: www.sjm.com/resources/learnmore about.aspx?section=CardiacPacemakerSystem

Boston Scientific: www.bostonscientific.com/ templatedata/imports/HTML/lifebeatonline/ resources.shtml

Reflective model

You will find this reflective model template and many others under the career development tab on the AfPP website.

References

Allen M 2006 Pacemakers and implantable cardioverter defibrillators Anaesthesia 61 (9) 883-890

American Heart Association 2008 Living with your pacemaker (online) Available from: www.americanheart.org/presenter.jhtml?identifier=467 6 [Accessed 20 August 2008]

American Radio Relay League 2002 Interference: Its Potential Effect on Pacemaker Systems (online) Available from: www.arrl.org/tis/info/ pcmkr.html [Accessed 20 August 2008]

Armstrong K, Williams T 2007 Awareness--Interference in the Medical Environment (online) Available from: www.emcuk.co.uk/awareness/ Pages/InterferenceExamples/Medical.htm [Accessed 20 August 2008]

British Heart Foundation 2005 Pacemaker Heart Information Series 15 (online) Available from: www.bhf.org.uk/faqs.aspx?qid=7783 [Accessed 20 August 2008]

ERBE Elektromedizin 2007 Principles of Electrosurgery Tubingen, ERBE Elektromedizin

Fogoros RN 2003 Pacemakers--what you should know (online) Available from: http://heartdisease.about.com/cs/arrhythmias/a/pa cemakers_3.htm [Accessed 20 August 2008]

Medicines and Healthcare products Regulatory Agency 1996 PTN No 61 Possible Interference or Interaction between Cellular Mobile Telephones (especially Digital GSM) and Implantable Pacemakers and Defibrillators (online) [no longer available]

Medicines and Healthcare products Regulatory Agency 2002 PTN No 90 Under-reporting of adverse incidents involving implantable pacemakers (IPGs) and implantable cardioverter defibrillators (ICDs) to the Medical Devises Agency (MDA) (online) Available from: www.mhra. gov.uk/Publications/Safetywarnings/MedicalDeviceAle rts/CON008923 [Accessed 20 August 2008]

Medicines and Healthcare products Regulatory Agency 2006 Guidelines for the perioperative management of patients with implantable pacemakers or implantable cardioverter defibrillators, where the use of surgical diathermy/electrocautery is anticipated (online) [no longer available]

Medicines and Healthcare products Regulatory Agency 2007 Briefing on interference between personal MP3 players and implantable pacemakers and implantable defibrillators (online) Available from: www.mhra.gov.uk/ NewsCentre/Pressreleases/CON2031181 [Accessed 20 August 2008]

Medicines and Healthcare products Regulatory Agency 2008 Medical Device Alerts (online) Available from: http://www.mhra.gov.uk/ Publications/Safetywarnings/MedicalDeviceAlerts/CO N202 [no longer available]

Nursing and Midwifery Council 2008 Standards of Conduct, Performance and Ethics for Nurses and Midwives London, NMC

Perko Z, Pogorelli Z, Bilan K 2006 Lateral thermal damage to rat abdominal wall after harmonic scalpel application Surgical Endoscopy 20 (2) 322-324

Senthuran S, Toff WD, Vuysteke A, Solesbury PM, Menon DK 2002 Implanted cardiac pacemakers and defibrillators in anaesthetic practice British Journal of Anaesthesia 88 (5) 627-631

Smith T, Smith J 2001 Electrosurgery in Otolaryngology--Head and Neck Surgery: Principles, Advances and Complications The Laryngoscope 111 (5) 769-780

Tonks A 2006 Implantable cardiac devices have substantial failure rate British Medical Journal 332 (7549) 1084-1085

Veitch A, Fairclough P 1998 Endoscopic diathermy in patients with cardiac pacemakers Endoscopy 30 (6) 544-547

Yeo T, Berg N 2004 Counselling patients with implanted cardiac devices The Nurse Practitioner 29 (12) 58-65

Ann Mash

RGN

Staff Nurse, Main Theatres, Lincoln County Hospital, Retford

Correspondence address: Main Theatres, Lincoln County Hospital, Retford, DN22 0PD.
Gale Copyright: Copyright 2008 Gale, Cengage Learning. All rights reserved.