43: Electrical Safety and Iatrogenic Complications of Edx studies

Question 1

When does the risk of electrical injury increase from leakage current?

Answer 1

1. Malfunctioning of the electrical equipment
2. Multiple electrical devices attached to the patient
3. Loss of the body’s normal protective mechanisms

Question 2

What is preferable, wooden or metal table?

Answer 2

Wooden (doesn’t conduct electricity)

Question 3

Machines should be turned on/off before/after attaching electrodes to the patient, and turned on/off before/after disconnecting the patient, to minimize the risk of power surges

Answer 3

on before;
off after

Question 4

What item should be avoided to reduce the risk of voltages developing on the reference electrodes? What should always be used to avoid current flows from reaching the patient?

Answer 4

Extension cords;
ground electrode

Question 5

What items/devices increase risk of electrical injury?

Answer 5

IV lines, central IV catheter, temporary external pacemaker

Question 6

When can Edx studies be performed on those with central lines?

Answer 6

With maintained equipment, use of ground electrodes, study contralateral UE, avoid proximal stim sites

Question 7

What muscles when sampled could lead to pneumothorax?

Answer 7

Diaphragm, serratus anterior, supraspinatus, rhomboids, cervical and thoracic paraspinals

Question 8

What medical conditions can increase risk of bleeding?

Answer 8

Thrombocytopenia (plts less than 20 k markedly increases risk); chronic renal failure, coagulopathies (liver failure, DIC), hemophilia

Question 9

Some ways to help with doing EMG on patients who are anticoagulated?

Answer 9

1. Use smallest gauge needle
2. Limit study to superficial muscles to promote prolonged compression
3. Avoid deep muscles that can’t be manually compressed and could lead to compartment syndrome (PT, FCR, tib post, FDL)
4. Avoid muscles where you could have hematomas (gluteal muscles near sciatic nerve, paraspinals near exiting spinal nerves)
5. Avoid muscles with large arteries or veins nearby; FPL near radial artery, iliacus near femoral artery/vein, AC fossa muscles near brachial artery)