Tourniquets

Complications

Systemic

Exsanguination

Embolisation risk (DVT, septic or tumour material)

Increased central volume and increased SVR (increased BP and CVP)

During its application

Tourniquet failure intra op

Bleeding if anterograde flow is not reduced and VR is obstructed

Tourniquet pain from one hour after inflation (increased HR and BP) - mediated by C fibres

Deflation

Blood volume shifts and release of anaerobic metabolites (lactate, K+) and CO2 causes metabolic and haemodynamic changes - myocard depression, reduced SVR and MAP, reduced CVP.

Bleeding

Embolisation risk (air, fat, cement)

Localised

Nerve and muscle injury

Poor application technique

Mechanical pressure (nerve), ischaemia (muscle)

Skin injury

Poor application technique

Moisture under padding

Microvascular injury

Post tourniquet syndrome (oedematous, pale, stiff limb with weakness but no paralysis)

Minimisation of complications

CI to tourniquet use

AV fistulas

PVD - risk damage to atheromatous vessels, causing fracture of plaque

DVT

Sickle cell disease

Poor skin integrity

Peripheral neuropathy

Cuff

Widest possible

20% greater than diameter of arm (enables lower inflation pressure for arterial occlusion (Force = inflation pressure x area beneath cuff)

Curved cuffs designed to fit conical parts of limbs (allow lower inflation pressures)

Where nerves are protected by overlying muscle

Regular maintenance

Skin protection

Ensure not pinched by tourniquet

Soft padding under tourniquet before inflation

Limb exsanguination

Prior to application of tourniquet

Time and pressure

Time

Short duration (max 2hrs)

Breaks for reperfusion if req after this time (10mins)

Pressure

Should have a relationship to the SBP (e.g. 50-100mmHg greater) to reduce anterograde flow

Maximal pressures are controversial

Normally 200mmHg is adequate for the UL and 250mmHg for LL (increase if atherosclerosis or morbid obesity)

Audiovisual time and pressure alarms

High and low pressure alarms

Tourniquet deflation

Anticipation with fluid bolus

Use of vasopressors

Hyperventilation

Vigilance for arrhythmia and MI

Tourniquet pain

Difficult to manage

Resistant to anaesthesia and analgesia

Only effective method is temp tourniquet release