OSCE Procedural Skills 3 — Questions and Answers
Question 1: During an arterial blood gas (ABG) collection from the radial artery, which test should be performed first to confirm adequacy of collateral circulation?
- Brachial pulse check
- Allen's test (Correct answer)
- Capillary refill test
- Doppler ultrasound
Correct answer: Allen's test
Allen's test assesses collateral ulnar circulation to the hand before radial artery puncture to reduce ischemia risk.
Question 2: A patient needs a wound suture. Which suture technique produces the least scarring in a cosmetically sensitive area?
- Horizontal mattress
- Subcuticular (intradermal) continuous suture (Correct answer)
- Simple interrupted suture
- Figure-of-eight suture
Correct answer: Subcuticular (intradermal) continuous suture
Subcuticular sutures lie beneath the epidermis, avoiding percutaneous needle marks and resulting in finer scars.
Question 3: When performing cardiopulmonary resuscitation (CPR) on an adult, what is the correct compression-to-ventilation ratio for a single rescuer?
- 15:2
- 30:2 (Correct answer)
- 5:1
- 30:1
Correct answer: 30:2
Current AHA/ERC guidelines specify 30 chest compressions followed by 2 rescue breaths for single-rescuer adult CPR.
Question 4: During chest drain insertion for a pneumothorax, at what triangle of safety should the drain be inserted?
- 2nd intercostal space, midclavicular line
- Lateral border of pectoralis major, 5th ICS, anterior axillary line forming the triangle of safety (Correct answer)
- 4th ICS, posterior axillary line
- 7th ICS, midaxillary line
Correct answer: Lateral border of pectoralis major, 5th ICS, anterior axillary line forming the triangle of safety
The triangle of safety is bounded by the lateral border of pectoralis major, lateral border of latissimus dorsi, and a line at the 5th ICS, minimizing neurovascular injury.
Question 5: A patient requires a knee joint aspiration. With the patient supine and knee extended, what is the preferred approach?
- Directly over the tibial tuberosity
- Medial or lateral to the superior pole of the patella (Correct answer)
- Through the patellar tendon
- Posteriorly through the popliteal fossa
Correct answer: Medial or lateral to the superior pole of the patella
The superolateral or superomedial approach, at the superior pole of the patella, accesses the suprapatellar pouch where fluid accumulates.
Question 6: When performing an ophthalmoscopy in an OSCE, which setting should be used to view the optic disc initially?
- Large beam, red-free filter
- Large beam, zero diopter setting (Correct answer)
- Small beam, blue filter
- Slit beam, +10 diopter setting
Correct answer: Large beam, zero diopter setting
Starting with the large beam at zero diopters allows initial visualization of the optic disc with the patient's refractive error compensated by the examiner.
Question 7: During a surgical scrub, what is the minimum recommended duration for the initial hand and forearm scrub before a sterile procedure?
- 1 minute
- 2–3 minutes
- 3–5 minutes (Correct answer)
- 10 minutes
Correct answer: 3–5 minutes
Guidelines recommend a 3–5 minute scrub for the first case of the day to achieve adequate reduction of transient and resident flora.
OSCE Procedural Skills 3
During an arterial blood gas (ABG) collection from the radial artery, which test should be performed first to confirm adequacy of collateral circulation?