1. Intro to Acute Limb Ishchemia

Question 1

What is ischemia?

Answer 1

lack of arterial blood to an organ

Question 2

What are factors affecting ischemia?

Answer 2

1. Rate of occlusion
2. Degree of obstruction
3. State of collaterals
4. Type of artery

Question 3

What is Acute Ischemia?

Answer 3

lack of blood flow due to:
Sudden & Complete obstruction w/o collaterals

Question 4

What are the intrinsic etiologies of acute ischemia?

Answer 4

-Embolism
-Acute thrombosis
-Instrument or drug injection

Question 5

What are the extrinsic etiologies of acute ischemia?

Answer 5

• Trauma
• Venous outflow blockage (PAD & PCD)
• Compartment syndrome

Question 6

What are the local effects of acute ischemia?

Answer 6

arterial occlusion → distal stasis → propagating thrombus → cellular hypoxia

Question 7

What are the hypoxic effects of acute ischemia?

Answer 7

1. ↑LA + Na-K pump failure → Na+ influx → edema
2. Endothelial injury → blebs → capillary narrowing
3. Elastin replaced by Fibrin → capillary narrowing
   Impaired Reflow Phenomenon

Question 8

What are the metabolic effects of acute ischemia?
(Reperfusion Syndrome/Myonephropathic Metabolic Syndrome)

Answer 8

1. Lactic acidemia
2. Hyperkalemia
3. Myoglobinuria → Renal Failure
   metabolites flood circulation w/revascularisation

Question 9

What are the clinical pictures of acute ischemia?

Answer 9

1. Pain (sudden)
2. Pallor (→ Cyanosis)
3. Pulselessness
4. Paresthesia
5. Paralysis
6. Poikilothermia

Note:
-light touch for early/late
-swelling w/acute tenderness = irreversible muscle infarction

Question 10

What are the investigations for acute ischemia?

Answer 10

• Duplex
• Arteriography
• For cause
• For complications
  Not done in threatened limb

Question 11

What are the preoperative treatments for acute ischemia?

Answer 11

• Hospitalization
• Analgesia
• IV fluids
• Prophylactic antibiotics
• Heparinization (for propagation):
  a. Unfractionated (w/adjuvant)
  b. LMW (w/o adjuvant)

Question 12

What are the operative treatments for acute ischemia?

Answer 12

• Embolic > Embolectomy
• Arterial injury > Deal w/bleeding
• Thrombotic > Endotracheal + Arterial Graft

Question 13

What are the post-operative treatments for acute ischemia?

Answer 13

1. Pre-op cause (AFib, Atherosclerosis, hypercoagulability)
2. Post-op complications:
   a. Gangrene > Amputation
   b. Acidosis > NaHCO3: ½ body wt x base deficit
   c. Crush syndrome:
   -Hyperkalemia (25 glucose + 10 insulin)
   -Myogloinuria (mannitol)