Tourniquet 1st half

ARTERIAL

TOURNIQUET

By Adithya Vishnu

Moderators : Dr W S Thatte

Dr Anitha Kulkarni

History

• Early Romans reduced blood loss by use of materials

like narrow bands during amputations.

• Jean Louis Pettie coined the term which in French

means to “turn”.

• Ambrose Perri - Tourniquet in Surgery

• John Von Esmarch - Esmarchs Tourniquet made of

rubber bandage.

• Harvey Cushing - Pneumatic Tourniquets

TYPES OF

TOURNIQUETS

• Battle Field Tourniquets

• Tourniquets - Esmarchs Tourniquets

• - Pneumatic Tourniquet

CLINICAL USE OF

TOURNIQUET

• Facilitate Surgery

• Prevention of Blood Loss

ROLE OF TOURNIQUET IN

SURGERY

• Promotes blood less surgical field.

• Reduces Blood Loss.

• Facilitates identification of structures.

• Reduces the operating time.

• Reduces Complication.

PRINCIPLES OF

APPLICATION OF

TOURNIQUET

• Pressure and time must be recorded.

• Care to be taken that disinfectant does not pass

under the Tourniquet. Can be prevented by

applying plastic drapes under the Tourniquet.

• Constant reminder of time.

APPLICATION OF

TOURNIQUET

• Exsanguination of the limb- Tissue Compression.

• Elevation of Limb for 2 Min.

• Padding - Closely and Snugly applied padding

prevents skin trauma.

• Inflation has to be done rapidly.

AIM OF TOURNIQUET

APPLICATION • To produce bloodless field at lowest pressure

1. The minimum pressure depends on - Limb size

2. Cuff size- 20 % the circumference of UL. 40 % the

circumference of LL.

• Amount of pressure to be applied

A. Arm : SBP + 50 - 75 mm of Hg

B. Lower Limb : SBP + 75- 100 mm of Hg or 2 x SBP

PATHOPHYSIOLOGY

Both systemic and local effects occur during

tourniquet usage.

Systemic effects are usually related to the inflation

and deflation of tourniquets.

Local effects are usually due to ischemia or direct

mechanical pressure.

SYSTEMIC EFFECTS -

CARDIOVASCULAR

EFFECTS • Clinically insignificant in healthy patient.

• Cardiac arrest and circulatory overload has been reported where

b/l thigh tourniquet were used.

A. During Inflation:

• Shift of blood to central circulation and increase in peripheral

vascular resistance.

• This is seen as a transient increase in SBP and CVP.

• After 30 - 60 min there is a second gradual increase in Blood

Pressure and Heart Rate - Tourniquet Pain

A. During Deflation :

• Redistribution of circulating volume back into the

limb and post ischaemic reactive hyperaemia.

• Metabolites accumulated in the limb are released

into the systemic circulation- Fall in BP and CVP.

• Studies have shown that Propofol can attenuate

this response because it can limit super oxide

generation.

RESPIRATORY

SYSTEM • Tourniquet inflation minimal effect.

• Tourniquet deflation can lead to immediate increase in

end tidal concentration of CO2 which peaks at 1 minute.

• Returns to baseline after 10 minutes.

• Greater when a lower limb tourniquet is released.

• Deflation leads to an increase in cardiac output and the

hypercapnic venous blood from the ischaemic limb

causes the rise in ETCO2.

• Seen as increase in minute ventilation in

spontaneously breathing patient.

• In controlled ventilation increasing the minute

ventilation 5 minutes prior to deflation keeps the

increase in CO2 levels to a minimum.

CENTRAL NERVOUS

SYSTEM • The rapid increase in ETCO2 after tourniquet

deflation increases the cerebral blood flow.

• Peaks at 2 minutes.

• Baseline within 10minutes.

• 50% increase in middle cerebral artery velocity

during this period.**

• Detrimental by worsening the secondary brain injury

in patients with increased intracranial pressure.

• Maintaining normocapnia can prevent this increase

in cerebral blood flow during deflation.

HAEMATOLOGICAL

CHANGES • The effects on the haematological system are complex.

A. During Inflation :

• Initially overall state of hypercoagulability

• Pain due to surgery and the tourniquet itself release

catecholamines which may cause platelet

aggregation.

• Tissue compression from the application of Esmarch

bandages - Platelet aggregation

• Despite this hypercoagulable state - ****NO DVT****.

A. During Deflation :

• A brief period of reduced coagulation

• Tissue plasminogen activator is released cause of

ischaemic effects.

• Systemic fibrinolysis after the tourniquet is deflated.

• This transient fibrinolysis is one of the contributors in post

tourniquet bleeding.

TEMPERATURE

REGULATION

A. During Inflation :

• Core body temperature is gradually - decreased

heat loss from the affected limb.

B. During Deflation:

• Transient fall in core temperature due to the

redistribution of body heat.

• Hypothermic blood from the ischaemic limb

increases the fall in core temperature.

CHANGE IN

METABOLISM

• During Inflation : Minimal / No changes

• During Deflation :

• Reversed in 30 min

• After 1-2 hours of limb ischaemia, plasma

potassium and lactate concentrations increases.

• Arterial pH of the systemic circulation falls due to

the increased lactate and carbon dioxide from

the ischaemic limb.

LOCAL EFFECTS -

NERVE • Supra-systolic pressure leads to a reversible

physiological conduction block in both motor and

sensory nerves approximately 15 – 45 minutes after

cuff inflation.

• Published evidence suggests ischaemia to be the

cause of such a conduction block .

• Mechanical compression seems to be more

responsible for the long lasting block than ischaemia.

• Morphological changes are seen in the large

myelinated nerves especially underneath the

proximal and distal edges of the tourniquet after

2 hours of inflation.

• This can last as long as 6 months, but

permanent changes are rare.

MUSCLE

• During Inflation :

• Progressive tissue hypoxia and hypercapnia.

• Energy stores are progressively consumed and finally

exhausted.

• Hypercapnia along with anaerobic metabolism -

development of intracellular acidosis.

• Inflation - short as 60 minutes can produce morphological

changes in mitochondria and local fibre necrosis.

• Ischaemia lasting longer than 2 hours can cause

microvascular injury in the muscle.