Vascular: Acute Limb Ischaemia

Question 1

what is acute ischaemia?

Answer 1

sudden loss of perfusion to a limb which develops over a short time

Question 2

what are the 6Ps?

Answer 2

• parasthesia
• pulselessness
• pallor
• paralysis
• pain
• perishingly cold

Question 3

characteristics of the pain

Answer 3

• constant
• severe
• sudden-onset

Question 4

other characteristics of acute limb ischaemia (non-salvageable)

Answer 4

• fixed mottling (non-salvgeable limb)

- blistering

Question 5

cause of acute limb ischaemia

Answer 5

• embolism
• post-MI
• valve disease
• aortic aneurysm
• arthrosclerosis (acute-on-chronic)
• popliteal aneurysm
• compartment syndrome
• blunt trauma
• iatrogenic trauma
• sharp trauma
• occlusion of the bypass graft
• haematological

Question 6

mention the 3 main areas where a thrombus can lodge

Answer 6

• saddle embolus (at a bifurcation)
• common femoral artery
• sudden changes of calibre

Question 7

what type of symptoms do patients with acute-on-chronic disease have?

Answer 7

same type; but much milder due to the development of collaterals

Question 8

what should you ask in the history?

Answer 8

• location/time of pain
• pale
• cold
• numb
• weak
• cardiovascular events
• smoking, HTN, hyperlipidaemia
• previous cardio/vascular surgeries
• history of AF
• drug history: warfarin, DOAC, pacemaker, valve replacement

Question 9

what should you examine?

Answer 9

• Inspection: colour of the limb (compare the sides), fixed mottling, blistering (indicates the severity)
• Check for surgical scars for valve surgery and bypasses
• Palpation: temperature, pulses (affected limb - none, normal limb - present, acute on chronic - might have both sides affected), sensation, power (of the muscle, if the toes on one side are affected, you would notice)
  ○ Water hammer pulse (more strong pulse proximal to the thrombus - likely that the thrombus is below that)
  ○ May still feel the pulse above the level of the embolus/thrombus - gives an idea where the embolus is
• Doppler: no arterial signal in acute limb ischaemia, venous signal are still present
  ○ Acute on chronic: sometimes, still have arterial signal

Question 10

management of acute limb ischaemia

Answer 10

• large bore cannula (take bloods)
• IV heparin
• crossmatch
• give oxygen and IV fluids as required
• IV morphine
• refer to vascular surgeon
• surgery time!

Question 11

surgery options in acute limb ischaemia

Answer 11

• thromboembolectomy
• thrombolysis
• fasciotomy

Question 12

what do you do in a thromboembelectomy?

Answer 12

• transverse/longitudinal incision
• open the artery and insert a catheter
• this goes beyond the thrombus to yank the thrombus out

Question 13

complications of thrombolectomy

Answer 13

• death
• surgical site infection
• further anticoagulation
• further ischaemic episodes
• psuedoaneurysm
• distal embolisation
• compartment syndrome

Question 14

what happens in compartment syndrome?

Answer 14

• muscle groups are damaged from the ischaemia
• when the blood is restored, the muscle groups swell up
• this presses on more compressible structures like veins, causing more blood to accumulate
• blood flow would slow down which can cause gross ischaemia due to arterial thrombosis