Tourniquet mgmc1

20. Dec 2016

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Tourniquet mgmc1

  1. Tourniquet Dr S Parthasarathy MD DA DNB PhD Dip. software statistics FICA
  2. Definition • A tourniquet is a constricting or compressing device used to control venous and arterial circulation to an extremity for a period of time. • Venous • Arterial !!
  3. History • The word tourniquet itself derives from the French verb tourner (to turn) and was first used by the eighteenth-century French surgeon Louis Petit describing the screw-like device he strapped to the thighs of patients undergoing leg amputations, to reduce blood loss.
  4. Taken from the internet for closed academic purpose only
  5. Esmarch Pneumatic – microprocessor controlled Pneumatic manual Petit original
  6. Indications • Surgery • Trauma • "Hand surgery without tourniquet is like • repairing a clock in an ink container" • For blood loss • IVRA anesthesia and sympathectomy
  7. Contra indications • Open fractures • Sickle cell disease • Plastic reconstructive surgery done • Sever hypertension • Compartment syndrome and compressions
  8. Types • Emergency • Esmarch • Pneumatic • Microprocessor controlled • Straight cuffs • Contour cuffs occlude the flow of blood at lower pressures than straight cuffs that are of the same width
  9. Parts of tourniquet • Inflatable cuff • Gas source ( nitrogen or air ) • Pressure display • Pressure regulator ( within 2-6 mmHg) • Connection tubing
  10. Size • 3 inches to 6 inches overlap • Width more than half the diameter • Tourniquets should be positioned on the limb at the point of the maximum circumference. • Soft padding – but no loose cotton • The choice of size of tourniquet should allow placement of two fingers between the cast padding and the cuff
  11. Exsanguination • Exsanguination before inflation of the tourniquet improves the quality of the bloodless field and minimizes pain associated with tourniquet use. • It is normally done by limb elevation or using an elastic wrap of the extremity. • Malignancy, infection thrombi,fracture – simple elevation or nothing – no wrapping • Rapid inflation – veins and arteries simultaneous
  12. Exsanguination and inflation pressures • Maximal exsanguination can be achieved by elevation of the arm or leg for 5 min at 90◦and 45◦ respectively, without mechanical compression. • 250 mmHg for upper limb and 300 for lower limb • 100 and 150 above systolic for limbs – arbitrary
  13. Tourniquet Cuff Pressure • LOP can be defined as the minimum pressure required to stop the flow of arterial blood into the limb distal to the cuff.( limb occlusion pressure) Not well defined Preop LOP Safety in kids - ??
  14. Inflation or occlusion time • One hour • Not yet defined but may be up to three hours • 10 minute deflation interval every one hour • Double tourniquet and cold extremities – prolong • Pediatric patients – better less than 75 minutes
  15. Tourniquet related complications Local Systemic
  16. Local • Normal physiological conduction block in fifteen minutes • Nerve injuries – 0.37% • 1 in 6200 • upper limb • 1 in 3700 Lower limb • Edges of the cuff • Esmarch more – may be 1000 mm Hg • Radial N in Upper limb • Common peroneal N in lower limb more affected
  17. Muscle injury • Muscle injury tends to be greatest beneath the tourniquet because of the combination of ischaemia and mechanical deformation, and may persist after tourniquet deflation as a result of micro- vascular congestion • Post tourniquet syndrome – weakness palsy without anesthesia • Three weeks – usually normalize.
  18. Skin changes • cutaneous abrasions, blisters and even pressure necrosis. • The highest risk of skin injury occurs in: Children, obese, elderly, and patients with peripheral vascular disease • Direct vascular injury is an uncommon complication of tourniquet use.
  19. Systemic effects- CVS • Limb exsanguination and tourniquet inflation increase blood volume and systemic vascular resistance that ultimately cause a transient increase in central venous pressure • Systolic BP and diastolic BP with heart rate rise • 800 ml – exsanguinated sometimes • How to decrease the rise in BP ? • 0.25 mg/ kg of intravenous ketamine
  20. • After deflation , this may come back to cause hypotension • Arrests after both lower limb deflation reported • Reasons • Post ischemic reactive hyperemia • Anerobic metabolites
  21. Respiratory system • ETCO2 increase after deflation • 1. 6 to 2.4 kpa • This increase is due to the efflux of hypercapnic venous blood from an ischaemic area into the systemic circulation, and an increase in cardiac output following deflation of the tourniquet • Spontaneous – 6n minutes – normal ,, controlled ventilation – a little extra
  22. Cerebral • Increased ETCO2 – increased cerebral blood flow in 2 minutes but comes back to normal in ten minutes • Middle cerebra artery blood flow – 50 % rise • Patients where it matters – beware • Hyperventilate before deflation
  23. Hematological • Tourniquet inflation during surgery is associated with a global hypercoagulable state. • This is attributable to increased platelet aggregation caused by catecholamines released in response to pain from surgery and the tourniquet itself. • Fibrinolysis after deflation - between - 15 – 30 minutes – may be increased bleeding – increased tissue tpa release • DVT no change if no tourniquet in TKR • Release before wound closure- more blood loss.
  24. Excess bleeds intra op • Common causes of intraoperative bleeding include incomplete exsanguination of the limb and a poorly fitting or under- pressurized cuff. • Intraoperative bleeding may also be caused by blood entering through the intramedullary vessels of long bones.
  25. Temperature changes • An increase in core body temperature occurs during the inflation of arterial tourniquets because of reduced metabolic heat transfer from the central compartment to the peripheral compartment and also from decreased heat loss from distal skin. • Deflation can cause decrease -- – 0.5 – 1 degrees
  26. Metabolic changes • On deflation --- Increased lactic acid, PaCO2,and potassium levels, and decreased levels of PaO2, and pH. • Toxic metabolites produce pathophysiological changes when released into the general circulation. • 30 minutes – becomes normal
  27. Pharmacology • We have isolated the limb • Does administration of some other drug influence • E.g we have applied tourniquet to both lower limbs – will the dose of propofol change ? • So far not studied , but relevance seems less. • Intravenous antibiotics – possible 10 minutes prior to inflation
  28. Tourniquet pain • Tissue compression – release of prostaglandins • A fbres are blocked by mechanical compression • Mostly “c” fibres • NMDA agonism and central sensitization • Dull aching poorly localized tight pain or discomfort • Increased HR and BP ( touniquet hypertension) • Difficult to prevent and treat this – even in spinal and dense blocks
  29. Tourniquet pain • 45 minutes usual – • That’s pressure pain – touch sensation should go • Adjuncts – clonidine opioids , adrenaline bicarb • Local anesthetics at the cuff edge , EMLA • Intravenous ketamine, dexmed , remifentanyl, • Magsulf • Preemptive gabapentin • Conversion to GA • Deflate and reinflate
  30. Other effects • Post op pain, edemas and infection increased if we do with tourniquet tibia plates and nails • Ream with touniquet - ? Bone necrosis • femur fracture was treated by intramedullary nail, tourniquet use for other lower limb fractures might increase pulmonary morbidity
  31. Summary • History • Types • Pressure , time • Systemic changes • Local changes • Tourniquet pain