Surgery Flashcards
1
Q
What is the temperature of liquid nitrogen?
A
–196°C
2
Q
What is the temperature required for cell death for each of the following:
- Melanocytes,
- Benign lesions, and
- Malignant lesions?
A
- Melanocytes: –5°C
- Benign: –25°C
- Malignant: –50°C
3
Q
What is the definition of electrosurgery?
- What kind of current is used?
- What does it rely upon to convert electrical energy into thermal energy?
- Which has a lower resistance - a thinner or wider electrode tip?
A
- High-frequency alternating current (AC) to conduct energy via a cold-tipped electrode
- High-frequency AC current prevents depolarization of muscles and nerves
- Relies on the high resistance of human tissue, a poor electrical conductor, to halt the flow of current and convert electrical energy into thermal energy, resulting in heat-induced tissue destruction
- A wider electrode tip has lower resistance than a thinner electrode tip
4
Q
Define electrocautery.
- Is it direct or alternating current?
A
- Direct current supplies energy to generate heat
- Direct application of heat to tissue via hot-tipped electrode
- There is no current flowing through the patient
- Hemostasis is through direct application of heat
- Safe for patients with implantable devices
5
Q
True or False:
Monopolar and bipolar CAN be used to describe electrosurgery.
A
False
- These two (frequently misused) terms should NOT be used when describing electrosurgery!
6
Q
What does monoterminal mean?
- How does this affect the voltage needed?
- What (2) modalities does are monoterminal?
A
- No grounding pad
- Because there is no electrode to dissipate the accumulated current, higher voltages are needed to reach desired level of tissue distruction
- Includes electrodesiccation and electrofulguration
7
Q
What is the difference between electrodessication and electrofulguration in terms of tissue contact?
A
- Electrodessication requires tissue contact
- Electrofulguration does NOT require tissue contact
8
Q
What does biterminal mean?
- How does this affect the voltage needed?
- What (2) modalities does are biterminal?
A
- Always has a dispersive electrode to recycle current
- Current travels through body and exits via grounding pad
- Provides outlet of return of current to the device, which permits increased amperage and reduced voltage
- Includes electrocoagulation and electrosection
9
Q
What is the difference between monoterminal and biterminal circuits used in electrical hemostasis?
A
10
Q
Are electrodessication and electrofulguration monoterminal or biterminal?
- Which requires direct contact?
A
Electrodessication and electrofulguration are BOTH monoterminal
- The difference between the two is that electodessication REQUIRES direct contact with the tissue, whereas in electrofulguration there is NO direct contact (i.e., the probe is held at a distance and there is a “spark gap”).
- Electrofulguration results in more limited, superficial tissue destruction
11
Q
Are electrocoagulation and electrosection monoterminal or biterminal?
A
Biterminal
12
Q
What is the difference between electrocoagulation and electrosection?
- Are they monoterminal or biterminal?
- Which is undamped? Damped?
A
- Both biterminal and high amperage (can penetrate tissue deeper)
- Electrocoagulation is a damped waveform causing some cell destruction but mainly hemostasis
- Electrosection is an undamped waveform which results in pure cutting with minimal collateral tissue destruction, and NO hemostasis
13
Q
What should be used for electrical hemostasis in patients with pacemakers and defibrillators? (2)
A
- Biterminal electrocoagulation
- Electrocautery
14
Q
What are indications for incision and drainage of hematomas?
- Expanding hematomas in what areas are considered medical emergencies?
A
- Large expanding hematomas (often with acute throbbing pain) can present 1-2 days after surgery
- Expanding hematomas of the periorbital region (can lead to blindness) and neck (can lead to airway compromise) are medical emergencies
- Early hematomas can also be aspirated with a 16 or 18 gauge needle
15
Q
What is the mechanism of action of local anesthetics?
A
- Reversible inhibition of sodium ion influx –> blocks nerve conduction
16
Q
What is the pulse rate (low/high) and blood pressure (low/high) of the following:
- Vasovagal reaction,
- Epinephrine reaction, and
- Anaphylactic reaction?
A
17
Q
What is the treatment for the following:
- Vasovagal reaction,
- Epinephrine reaction, and
- Anaphylactic reaction?
A
18
Q
What are classically the first signs of lidocaine overdose?
A
- Circumoral and digital parethesias
- Metallic taste
- Talkativeness
- Euphoria
- Lightheadedness
19
Q
What are indications for antibiotic prophylaxis for dermatologic surgery?
- What things or surgical sites would increase the risk of infection?
A
- High risk for prosthetic joint infection
- High risk for infective endocarditis
- High risk surgical sites, including below the knee, groin, skin graft at any site and wedges or flaps of the ear, lip or nose
20
Q
What prophylactic antibiotics can be used for a high risk surgical site infection of a site that breaches the oral mucosa?
A
21
Q
What prophylactic antibiotics can be used for a high risk surgical site infection of any skin graft at any site, wedge excision or flap on the ear, lip or nose?
A
22
Q
What prophylactic antibiotics can be used for a high risk surgical site infection of the lower legs and groin?
A
23
Q
What is the difference between amide and ester anesthetics?
- Where are they metabolized?
- What are allergic reactions commonly due to?
- What are contraindications?
A
Amides have 2 Is in their name; Esters have only 1 I
- Amides: metabolized via CYP 3A4 in liver; allergic reactions are rare and usually to methylparaben preservative; contraindication: end-stage liver disease
- Esters: metabolized via pseudocholinesterases in plasma; renally excreted, frequent allergic reactions to PABA metabolite; contraindications: allergy to PABA, pseudocholinesterase deficiency, renal insufficiency
24
Q
What is the anesthetic of choice in pregnancy?
- Can epinephrine be used?
A
Lidocaine
- Note: epinephrine is pregnancy category C and will decrease uterine blood flow
- Epinephrine can be used if it is diluted to 1 : 300,000
25
What is the maximum _pediatric_ dose of lidocaine _with and without_ epinephrine?
* **1.2 - 2 mg/kg _WITHOUT_ epinephrine**
* **3 - 4.5 mg/kg _WITH_ epinephrine**
26
What is the maximum _adult_ dose of lidocaine _with and without_ epinephrine? What about in pregnant women?
* **4.5 - 5 mg/kg WITHOUT epinephrine**
* **7 mg/kg WITH epinephrine**
* Epinephrine can be used in pregnant women if diluted to 1 : 300,000
27
Which **amide anesthetic** has the longest duration of action when combined _with_ epinephrine? _Without_ epinephrine?
* **Bupivicaine + epinephrine lasts 8 hours and is used in big Mohs cases** (and has highest risk of cardiac toxicity)
* **Ropivicaine has longest duration by itself at 6 hours**
28
What are ways to decrease pain with injection? (3)
* Pinch/rub surrounding skin ("Gate theory" of pain)
* Add bicarbonate
* Warm anesthetic
29
What are the notable differences between **EMLA** and **LMX**?
* Which requires occlusion?
* Which increases the risk of methemoglobinemia in infants?
* Which cannot be used near the eye?
* **EMLA:** mixture of 2.5% lidocaine + 2.5% prilocaine
* **Requires occlusion**
* **Risk of methemoglobinemia in infants** from prilocaine component
* Cannot use near eye (corneal injury)
* **LMX4:** 4% lidocaine
* Does not require occlusion
30
What is the maximum daily dose of acetaminophen in adults \< 60 years old, \> 60 years old and those with liver failure?
* Adults \< 60 years old: 4 g
* Adults \> 60 years old: 3 g
* Liver failure: 2 g
31
How long should you stop aspirin in the perioperative period?
Withhold for **10 days prior** and **5-7 days after** surgery as long as no increased risk of stroke or MI for patient
32
True or False?
Thienopyridines (e.g., clopidogrel and ticlopidine) SHOULD be stopped prior to surgery.
**False**
* Do NOT stop taking clopidogrel or ticlopidine if it is for a cardiac or neurologic indication
33
Should a patient stop warfarin prior to a procedure?
No, but **ensure INR is \< 3**
34
Which herbs and supplements enhance warfarin and inhibit platelet adhesion and therefore should be stopped prior to dermatologic surgery?
35
Which antiseptic should NOT be used around the eyes or ears?
**Chlorhexidine**
* Can cause severe corneal damage and ototoxicity
36
Name the instrument in this photograph and what it is classically used for.
**Allis clamps**
37
Name the types of scissors in this photograph.
38
Name the needle holders in this photograph.
39
Name the instruments in this eyelid surgical tray.
40
Name the instruments in this facial surgical tray.
41
Name these instruments (from left to right) contained in this trunk or extremity surgical tray.
42
Name the needle anatomy (i.e., the parts of the needle).
* Where should the needle be grasped with the needle driver?
* The **shank, body and point** are shown, as well as specific needle points for different types of cutting
* Needles should be grasped at approximately **one-third of the distance from the shank to the point**. Avoid placement on or near the swaged area or near the tip.
43
Where is the desired undermining plane for trunk/extremities?
* For small or superficial defects?
* For larger excisions or melanomas?
* Mid-deep fat (for small or superficial defects)
* Just above deep fat (larger excisions or melanomas)
44
Where is the ideal undermining plane for the face?
* **Superficial to SMAS** to preserve motor nerves
45
What is the recommended surgical margin for a **BCC**?
* What about for high risk subtypes (e.g., recurrent or with aggressive histology)?
* **4 mm** for most tumors
* **0.6 cm - 1.0 cm margins or Mohs** for high risk subtypes (e.g., recurrent or with aggressive histology, etc.)
46
What is the recommended surgical margin for an **SCC**?
* What about for high risk subtypes?
* **4 mm** for most
* **0.6 mm or Mohs** for high risk subtypes
47
What are the recommended surgical margins for **DFSP**?
* Excision must extend to what?
* **2-3 cm** margins extending at least to fascia, or Mohs
48
What are the recommended surgical margins for:
* Melanoma in situ
* Breslow depth \< 1 mm
* Breslow depth 1 - 2 mm
* Breslow \> 2 mm
* **Melanoma in situ:** 0.5 cm - 1 cm
* **Breslow depth \< 1 mm:** 1 cm to deep fat or fascia
* **Breslow depth 1 - 2 mm:** 1 - 2 cm to fascia
* **Breslow \> 2 mm:** 2 cm to fascia
49
Which type of electrical hemostasis has the **highest risk of interference** with pacemakers and defibrillators?
Electrosection
