Electromagnetic Interference
OVERVIEW
- electromagnetic interference can affect the function of implanted electronic devices such as pacemakers and ICDs
CAUSES
- diathermy (monopolar & bipolar)
- mobile phones (don’t place over pacemaker)
- MRI
- shivering
- fasciculations
- alterations in heart size
- positive pressure ventilation
- peripheral nerve stimulators
- TENS machine
- defibrillation
EFFECTS ON PACEMAKERS AND ICDs
- inappropriate triggering or inhibition of output
- asynchronous pacing
- reprogramming
- damage to device circuitry
- pacing wires may acts as aerials and cause heating of endocardium
PREVENTION
- use bipolar diathermy
- if conventional diathermy required → position plate so that most of current passes away from the pacemaker, use short, sharp bursts and watch SpO2 or art line.
- ensure all devices are not in the same vector as the pacemaker current (between pacemaker and heart)
- if reason for pacemaker severe heart failure where loss of AV synchrony may precipitate haemodynamic compromise -> have a telemetric programmer and cardiac technician close @ hand
- keep lithotripter at least 6 inches away from pacemaker (should be timed with ECG and rate modulation deactivated)
- if have to defibrillate keep pads as far from pace maker as possible
- avoid sux c/o fasciculations (if used in a patient with a sensing mode activated -> use defasciculating dose of NDNMBD)
- avoid using defibrillation if at all possible (high level of EMI) -> if required use AP pad configuration and keep pad’s 10cm away from pacemaker
MAGNETS
- no longer recommended to place magnet over pacemakers, only applicable to older non reprogrammable pacemakers
- placement of a magnet would default mode to an asynchronous mode or a fixed rate
- all modern pacemakers are reprogrammable
MANAGEMENT OF PACEMAKER MALFUNCTION
- get help
- remove electromagnetic interference
- precordial thumps (percussive pacing)
- isoprenaline
- adrenaline
- transthoracic external pacing (capture around 80mA)
- trans-venous pacing
- transoesophageal pacing
References and Links
- CCC — Pacemakers
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC