EDT Patient Preparation & Safety 3 — Questions and Answers
Question 1: Which patient position is recommended when performing lower-extremity nerve conduction studies to minimize limb volume effects and ensure reproducibility?
- Patient seated upright with legs dangling
- Patient supine with the limb fully supported and relaxed (Correct answer)
- Patient prone with knees flexed to 90 degrees
- Patient standing to allow natural muscle tone
Correct answer: Patient supine with the limb fully supported and relaxed
A supine position with the limb supported and relaxed standardizes limb geometry, reduces muscle tension artifacts, and improves inter-study reproducibility.
Question 2: Why is limb temperature monitoring critical before performing nerve conduction studies?
- Cold temperatures increase nerve conduction velocity, leading to false-positive results
- Low limb temperature slows conduction velocity and prolongs distal latencies, mimicking neuropathy (Correct answer)
- Temperature affects only sensory amplitudes, not motor latencies
- Temperature monitoring is only required for pediatric patients
Correct answer: Low limb temperature slows conduction velocity and prolongs distal latencies, mimicking neuropathy
Conduction velocity decreases approximately 1.5–2.4 m/s per degree Celsius of cooling, so cold limbs can produce falsely prolonged latencies consistent with neuropathy.
Question 3: A patient with hepatitis C is scheduled for needle EMG. What is the correct needle handling protocol?
- Use disposable single-use needles and discard in an approved sharps container immediately after use (Correct answer)
- Sterilize the needle in alcohol between muscles to save costs
- Reusable needles are acceptable if autoclave-sterilized between patients
- Wear double gloves but standard disposal in regular waste is acceptable
Correct answer: Use disposable single-use needles and discard in an approved sharps container immediately after use
Single-use disposable needles eliminate cross-contamination risk and must be discarded immediately into a puncture-resistant sharps container per OSHA bloodborne pathogen standards.
Question 4: During needle EMG, the technician notices visible muscle fasciculations at a needle insertion site in a patient with suspected ALS. What is the appropriate response?
- Immediately withdraw the needle and terminate the study
- Document the finding, note the muscle, and continue with the planned examination (Correct answer)
- Apply ice to reduce spontaneous activity before proceeding
- Increase needle insertion depth to reach a deeper muscle layer
Correct answer: Document the finding, note the muscle, and continue with the planned examination
Fasciculations are a clinically significant finding that should be documented in the specific muscle and reported; the examination should continue to gather complete diagnostic data.
Question 5: Which of the following represents the correct procedure if a needle electrode accidentally contacts bone during EMG?
- Withdraw the needle slightly, reposition, and continue recording
- Discard the needle immediately and use a new one, as the tip may be bent or burred (Correct answer)
- Continue recording, as bone contact does not affect the needle tip
- Apply more insertion force to pass through the periosteum
Correct answer: Discard the needle immediately and use a new one, as the tip may be bent or burred
Contact with bone can blunt or deform the needle tip, increasing insertion pain and tissue trauma; a new needle should be used to maintain patient safety and signal quality.
Question 6: When obtaining informed consent for an electrodiagnostic study, which element is legally and ethically required?
- Patient must sign consent only for needle EMG, not for nerve conduction studies
- Patient must be informed of the procedure, its purpose, risks, benefits, and alternatives (Correct answer)
- Verbal consent is never acceptable; only written consent is valid
- Consent is only required for patients under 18 years of age
Correct answer: Patient must be informed of the procedure, its purpose, risks, benefits, and alternatives
Valid informed consent requires disclosure of the procedure, its purpose, material risks (e.g., discomfort, bleeding, infection), benefits, and alternatives, allowing the patient to make an autonomous decision.
Question 7: To minimize the risk of infection transmission in the EDX laboratory, which practice is correct regarding surface electrode reuse?
- Wipe surface electrodes with a dry cloth between patients
- Disinfect reusable surface electrodes with an EPA-approved disinfectant between patients (Correct answer)
- Surface electrodes never require disinfection as they contact only intact skin
- Soak surface electrodes in saline for 10 minutes between uses
Correct answer: Disinfect reusable surface electrodes with an EPA-approved disinfectant between patients
Reusable surface electrodes must be cleaned with an EPA-registered disinfectant between patients to reduce transmission of microorganisms, including MRSA.
EDT Patient Preparation & Safety 3
Which patient position is recommended when performing lower-extremity nerve conduction studies to minimize limb volume effects and ensure reproducibility?