Safety

Question 1

List 5 considerations that reduce risk to the device patient undergoing a surgical procedure.

Answer 1

1. Avoid electrocautery where possible
2. Electrocautery is contraindicated within a few inches of device
3. Electrocautery return electrode to be placed on leg, away from device
4. Program DOO or VOO or place a magnet over device
5. Test device pre and post surgery to identify any anomaly

Question 2

What is a likely outcome in the device patient undergoing surgery when none of the 5 considerations from card 1 are applied?

Answer 2

Electrocautery causes inhibition of pacemaker output (asystole in CHB patients).

Prevent by either contraindicating electrocautery or programming a non-sensing mode (DOO, VOO).

Question 3

True / False

When using an external defibrillator, the pads should be placed more than 10cm away from the device.

Answer 3

True.

Question 4

True / False

When using an external defibrillator, the pads should be placed parallel to axis of the pacemaker leads.

Answer 4

False.

Pads should be placed perpendicular to the axis of the pacemaker leads. This minimises the current induced by the leads.

Question 5

For planned cardioversion it is important to test the generator pre and post defibrillation.

Answer 5

True.

Although devices have a protection circuit (zener diode), its not impossible for this circuit to be overwhelmed and damage sustained.

Question 6

List 3 types of electromagnetic interference (EMI) respondent to treatment therapies.

Answer 6

1. MRI
2. Radiotherapy
3. Shock Wave Lithotripsy

Question 7

List a common source of EMI experienced by tradesmen/mechanics/engineers.

Answer 7

ARC welding.

This is contraindicated as it may cause oversensing, which can potentially lead to pacing inhibition.

Question 8

List common benign sources of EMI interference that occur outside the hospital.

Answer 8

1. Cell Phones
2. Metal detector security gates
3. Electronic article security gates
4. Microwave oven
5. Induction cooker top

Generally these items are not contraindicated but it’s advisable to maintain distance where possible.

Question 9

Define the safety feature ‘pacemaker reset’.

Answer 9

A reversion to VVI programming respondent to significant EMI interference.

High level interference can erase programming stored on RAM (such as event recordings and diagnostics) but not safety functions stored on ROM (such as pacing mode).

Question 10

True / False

Fever within 24 h before implantation is not associated with the development of device infection.

Answer 10

False.

Fever is linked to device infection and should be screened accordingly. If patient presents with a fever the device implant should be delayed.

Question 11

Should all remote infections be treated prior to implant.

Answer 11

Yes.

However if urgent, the risk of infection should be balanced against intervention timing. An alternative would be a tempoaray pacing wire to maintain haemodynamics until infection is treated.

Question 12

True / False

There is an increased risk of site infection in patients undergoing preoperative hair removal.

Answer 12

True.

Perioperative hair removal isn’t recommended except when hair is at or around the incision site.

Question 13

True / False

Perioperative antiseptic skin preparation should be performed with an approved antiseptic agent.

Answer 13

True - Normally chlorhexidine or iodine solution.

Antiseptic should be applied over the incision site in concentric circles starting from the incision site and moving toward the periphery.

Question 14

Why are systemic prophylactic antibiotics at the time of implantation recommended despite the low incidence rate of infection?

Answer 14

Extremely severe outcome if it does happen with entire system removal necessary.

Device infection is arguably the worst complication to treat.

Question 15

The following are types of _____ devices and are used to protect against _____.

‘Masks, caps, gowns, drapes, and shoe covers’.

Answer 15

Barrier devices are designed to maintain sterility and protect against infectious blood / bodily fluids.

Question 16

True / False

Physicians should perform a surgical scrub for ~5 min with an appropriate antiseptic agent.

Answer 16

True.

Question 17

True / False

Good surgical technique reduces the risk of infection.

Answer 17

True.

Question 18

What can be done for lean or small subjects who are thought to be at risk of pocket erosion.

Answer 18

Implant device subpectorally.

Question 19

What type of dressing is applied post-procedure to reduce infection and haematoma formation risk.

Answer 19

Pressure dressing.

Typically applied for 12-24hrs post implant.

Question 20

True / False

Should a hematoma form, is it recommended to drain it.

Answer 20

False - unless skin tension is severely increased.

Needle aspiration should be avoided due to risk of skin flora introduction into the pocket and ensuing infection.

Question 21

True / False

Evidence suggests that a short course (2days) of postoperative antibiotics is just as effective as a longer course (7days) in preventing device infections.

Answer 21

True.

Question 22

True / False

As one moves away from the ionising radiation source, dose is decreased by square of the distance as described by the inverse square law.

Answer 22

True.

Question 23

How do you calculate exposure time.

Answer 23

Exposure rate x Time.

Question 24

With regards to radiation safety monitoring, what is one piece of equipment all staff should wear.

Answer 24

Radiation tag.

Question 25

Describe a radiation tag and how does it work?

Answer 25

A tag with a piece of photographic film inserted. When the film is irradiated, an image of the protective case is projected on the film, the intensity of which is used to measure dose.

Question 26

In terms of radiation safety, what does ALARA stand for?

Answer 26

As Low As Reasonably Achievable.

Question 27

List 4 ways in which the radiation dose recieved can be reduced.

Answer 27

1. Wear radiation protection clothing (Leads, Glasses, Hat)
2. Stand behind radiation screens
3. Stand within the control room behind shielded glass when possible
4. Put as much distance between yourself and the radiation source

Question 28

A DR PPM patient is due for cardioversion - which is appropriate preparation?

1. Defib pads placed laterally to lead system
2. Defib pads placed perpendicular to lead system
3. Defib pads placed paralell to lead system
4. Place magnet over device
5. Reprogram device to DOO

Answer 28

2.

Keeping current away from system is vital to ensure energy isnt shunted down the leads to lead/myocardium interface which could cause localised ablation (resulting in increased sensing/pacing thresholds). Reprograming/Magnet application will do nothing to prevent this.

Question 29

A patient with LVAD is recieving multiple shocks. Upon interrogation you see chaotic R-R intervals that dont look physiologic. Whats the most likely explanation?

Answer 29

EMI from the LVAD system.

Question 30

Yes / No

An MRI safe device was implanted in a patient two weeks ago who presents to ED with fractured hip from witnessed fall. The consultant wants an MRI to assess - is this possible?

Answer 30

No.

Although MRI safe, the device and leads aren’t matured enough at 2 weeks. 6 weeks is the recommended post-op interval for lead maturation to occur.

Question 31

‘DDD 50/130bpm, AVD 160ms, PVAB 250ms’.

Post shoulder reconstruction patient with settings above is in the ward pacing at 65bpm with no atrial pacing/tracking. You weren’t given prior notification of this procedure. What is the appropriate course of action?

1. Reprogram generator
2. Replace generator
3. Obtain X-ray
4. Place a magnet over device

Answer 31

1 - Reprogram device.

With no prior warning given it is unlikley the device was reprogramed DOO for surgery. Thus the device has likely entered noise reversion backup mode respondent to EMI from electrocautery.

Question 32

ICD patient is flying abroad. When they walk through the airport scanner, what will happen?

1. Device will sense tachycardia and begin therapy
2. Device will reset
3. Inhibition of pacemaker output
4. Airport scanner will go off

Answer 32

4 - Airport scanner will go off.

Its perfectly safe to pass through airport scanners with a device. Remind the patient to carry their ID card as they will be asked to show it.