1.39 Tourniquet

Question 1

Systemic effects of tourniquet use

Answer 1

Post inflation

1 ↑ SVR = ↑ Circulating volume = ↑ CVP + initial ↑ BP

2 Slow gradual ↑ in BP ?d/t pain

3 Induced hypercoagulable state
- catecholamine induced platelet aggregation

4 Slow ↑ core body temp
- lack heat transfer in limb

Question 2

Systemic effects of tourniquet use

Answer 2

Post deflation

1 ↓ CVP + BP d/t blood volume and cold ischaemic metabolite distribution

2 ↑ EtCO2

• mixed venous PvCO2
• ↑ CO (2nd to bp drop)

3 ↑ EtCO2 -> ↑ CBF + ↑ ICP
(caution TBI)

4 Enhanced fibrinolysis
↑ Plasminogen activator release in hypoxic acidotic limb

5 ↓ Core body temp
<- redistributed cold acidotic blood

6 Metabolic changes
↑ plasma K
lactate
O2 consumption
CO2 production
↓ pH

Question 3

Contraindications to arterial tourniquet during surgery

absolute

Answer 3

Absolute

1 AV fistula

2 Severe PVD

3 Previous vascular surgery

4 evidence of long bone # or thrombosis at proposed tourniquet site

Question 4

C/I Tourniquet

Relative

Answer 4

1 Sickle Cell disease
- require pre optimisation analgesia o2 hydration and temp

2 Hx of Thromboembolic diz

3 Skin grafts

4 Localised infection

5 Lymphoedema
secondary to axillary clearance after breast surgery /radtx

Question 5

Local complications

Answer 5

1 Damage to skin
- Friction if tourniquet applied incorrect

• chemical burn
  leak alcohol skin prep beneath tourniquet

2 Damage to muscle

• swelling oedema hyperaemia
• rarely rhabdo / compartment syndrome
• 2nd to high cuff pressure or extended ischaemic time

Question 6

Local complications

Answer 6

3 Damage Vessels
- arterial vascular disease more susceptible - atheromatous plaque rupture

• May be severe enough require amputation

4 Damage to Nerves

• ↑ risk w/ extended limb ischaemic time
• poorly applied tourniquet
• direct neurological pressure effect

Motor function > sensory
large diameter fibres more susceptible

Lower limb > upper limb