CRNFA Hemostasis and Tissue Management 1 — Questions and Answers
Question 1: Which electrosurgical mode cuts tissue by delivering continuous current that rapidly heats intracellular water to cause cell vaporization?
- Coagulation mode
- Blend mode
- Pure cut mode (Correct answer)
- Bipolar mode
Correct answer: Pure cut mode
Pure cut mode delivers continuous unmodulated current that heats cells so rapidly they explode (vaporize), producing a clean incision with minimal lateral thermal damage.
Question 2: A ligating clip should be placed at what minimum distance from the planned transection point to ensure secure hemostasis?
- 0.5 mm
- 1 mm
- 2–3 mm (Correct answer)
- 5 mm or more
Correct answer: 2–3 mm
Clips should be placed at least 2–3 mm from the transection site to allow a secure bite of tissue and prevent slippage off the vessel end.
Question 3: When using a harmonic scalpel (ultrasonic energy device), what is the primary mechanism of tissue sealing?
- Electrical coagulation of proteins
- Mechanical vibration denaturing protein to form a coagulum (Correct answer)
- Thermal conduction from the active blade only
- Radiofrequency energy at 300 kHz
Correct answer: Mechanical vibration denaturing protein to form a coagulum
The harmonic scalpel uses high-frequency mechanical vibration (55,500 Hz) to denature protein and form a coagulative seal without electrical current passing through the patient.
Question 4: Topical thrombin agents such as Thrombin-JMI work by activating which step in the coagulation cascade?
- Converting prothrombin to thrombin
- Converting fibrinogen directly to fibrin (Correct answer)
- Activating platelets via ADP pathway
- Inhibiting fibrinolysis
Correct answer: Converting fibrinogen directly to fibrin
Topical thrombin directly converts fibrinogen to fibrin, bypassing the intrinsic and extrinsic coagulation pathways to rapidly form a fibrin clot at the application site.
Question 5: Bone wax is most appropriately used to control bleeding from which type of source?
- Major arterial bleeding
- Venous oozing from soft tissue
- Bleeding from cancellous bone surfaces (e.g., sternum or cranium) (Correct answer)
- Capillary bleeding from skin edges
Correct answer: Bleeding from cancellous bone surfaces (e.g., sternum or cranium)
Bone wax is a mechanical hemostatic agent used specifically to tamponade bleeding from cut bone surfaces such as the sternum during cardiac surgery or the cranium during neurosurgery.
Question 6: Electrosurgical unit (ESU) current density is highest at which point in the circuit?
- Dispersive (grounding) pad
- The generator unit
- The active electrode tip (Correct answer)
- Along the connecting cable
Correct answer: The active electrode tip
Current density is highest at the small active electrode tip where tissue effect (cutting or coagulation) occurs, and lowest at the large dispersive pad where current spreads safely.
CRNFA Hemostasis and Tissue Management 1
Which electrosurgical mode cuts tissue by delivering continuous current that rapidly heats intracellular water to cause cell vaporization?