Optimizing use of Tourniquet in Orthopedics
Tourniquet is invaluable instrument to plastic, hand and orthopedic surgeon. It helps create a bloodless field for easy operation and reduces operative time. The advantages of tourniquet is no without its share of complication including nerve and skin injuries and devastating vascular lesions leading to amputation or death. A thorough understanding of the local and systemic effect of tourniquet is essential to minimize the complication. Various physical and pharmacological modifications reduce the reperfusion injury and also help increase tourniquet time.
Though all know the advantages and risk of tourniquet use. There is evidence to show that Tourniquet use results in more post operative pain, delayed recovery and increased infections.
All of these complications can be minimized by applying the latest scientific data available on tourniquet use.
Contraindications for the use of the pneumatic tourniquet
A. Open fractures : In the instance of closed fractures, exsanguinations may not be able to be accomplished with the use of an elastic wrap, eg Esmarch bandage. Use of the bandage could further injure the patient. Elevation of the extremity may be the only route of accomplishing some degree of exsanguination. However, elevation also may not be able to be accomplished due to the possibility of causing further neurovascular damage.
B. Post-traumatic lengthy hand reconstruction
C. Severe crushing injuries
D. Severe hypertension
E. Peripheral artery disease
F. Diabetes mellitus
G. Sickle cell anemia
H. Compartment syndrome
I. Malignant tumors
Effect of tourniquet and its clinical implication.
Tourniquet has varied local and systemic effects. Understanding the systemic effects and ways to modulate it can help in increasing tourniquet time safely.
|Muscle|| Both compression and ischemic changes.
Lactic acid buildup with mitochondrial changes.
Reduced contractile property of underlying muscles.
Phagocytic infiltration and increased vascular permeability.
Post tourniquet syndrome
Reduce duration of tourniquet
Displacement of nodes of Ranvier between compressed and uncompressed regions.
Increase in width of cuff
Use of limb contoured cuffs
|Skin||Pressure necrosis friction burns.
|Chemical burns||Use of skin protective stockinet
Avoid alcohol based disinfectants
|Cardiovascular system|| Increase in Central venous pressure and arterial pressure on inflation and fall in pressure on deflation.
Micro emboli on deflation.
| Intraoperative hypertension
Inadequate exsanguination of the limb undergoing surgery coupled with stasis and cooling may contribute to fresh thrombus formation.
| Use of ketamine at induction
Through exsanguination of limb
|Respiratory system||Increase in end-tidal carbon dioxide concentration on deflation and returns to normal by 3-6min.
|Metabolic system|| Increased plasma K+
Increased lactic acid and carbondioxide
Metabolic acidosis takes 20-40min to return normal.
|Buffering capacity is reduced by anaemia, hypovolaemia, metabolic acidosis or pre-existing vascular disease.
Prior cardiac diseases myocardium may be sensitised to catecholamines by anaesthetic agents causing arrhythmias in response to hyperkalemia.
|Central nervous system||Increase in cerebral blood flow and raise in intracranial pressure on deflation.
|Hematological||Hypercoagulable state on inflation due to Increased platelet aggregation caused by catecholamines released in response to pain.
Increased ﬁbrinolytic activity lasting 15-30min following deflation due to release of tissue plasminogen activator from vasa vasarosum in response to ischemia.
|Increased bleeding on deflation.||Usage of Aprotinin, Tranexemic acid nad fibrin sealant.|
|Temperature||Increase in core temperature due to decreased peripheral circualation.
Decreased limb temperature by 3-4 degree.
| A marked rise in temperature may cause the anaesthetist concern about the possibility of malignant hyperthermia.
Drying of tissues
In Ischaemic injury the cell is deprived of the energy needed to maintain ionic gradients and homeostasis, and failure of enzyme systems leads to cell death. A tissue which has been exposed to a period of ischemia when reperfused undergoes a series of changes which may be detrimental to the cells. Reperfusion injury is mediated by the interaction of various free radicals, endothelial factors and neutrophils. The return of toxic metabolites to the systemic circulation may also have serious metabolic effects reperfusion may also induce further local tissue injury. Local and systemic damage are associated with neutrophil accumulation in the microvasculature. Activated neutrophils adhere migrate across the endothelium and cause celllar destruction by releasing various free radicals, proteolytic enzymes and peroxidases. Of the various free-radical are generated, hydroxyl radical is the most reactive species, which is capable of damaging proteins, DNA and lipids. Lipid peroxidation disintegrates cell membranes causing swelling of cells. Swelling following tourniquet application contributes to post-operative pain. The increase in vascular permeability is caused by inflammatory response to free-radical action on endothelial cells. Fluid leak is associated with increased interstitial pressure within the fascial compartments of the upper and lower limbs which causes compression of the microvasculature and impairment of the blood supply. Heparin administration before application of the tourniquet has been associated with reduction of swelling, suggesting that some intravascular thrombosis is probably involved in the production of swelling.
Pharmacological modification of ischemia-reperfusion injury mainly involves reducing the production and effects of superoxide and secondary radicals. Generation of superoxide has been reduced using allopurinol, a xanthine oxidase inhibitor, whereas secondary production of the more cytotoxic hydroxyl radical is reduced by iron chelator desferrioxamine. Intracellular accumulation of calcium from external source or from damaged sarcoplasmic reticulum has been implicated in Post ischemic injury. Calcium-release modulators such as dantrolene have been shown to provide partial protection against reperfusion injury.Treatment with dantrolene sodium (4 mg/h) throughout the periods tourniquet and after removal was found to preserve the ultrastructural appearance of the quadriceps, soleus and anterior tibial muscles. In the same study in animals depot methylprednisolone by a single 8-mg intra-muscular injection led to preservation of the structure of tibialis anterior muscle fibres on both light and electron microscopy. High-dose continuous intravenous infusion with ascorbic acid (80 mg/h) throughout the period of tourniquet application preserved the structure of the muscle.
” Pharmacological modification must be used to limit Re perfusion injuries the drugs used are allopurinol, danthrolene, methyl prednisolone and ascorbic acid”
The concept using breathing periods represents an attempt to reduce ischaemic injury. This involves releasing the tourniquet after fixed period of ischemia to allow reperfusion, with the aim of returning tissue to its pre-ischaemic state before limb is subjected to a further period of ischemia. With knowledge of the ischemia–reperfusion syndrome, the use of breathing periods is illogical, as reperfusion is now recognized as a major cause of damage to limbs after ischemia. Continued damage by free-radical-mediated mechanisms is likely even after the biochemistry of the venous blood returns to normal equilibrium. Animal studies have suggested that allowing reperfusion may actually increase the amount of damage to the ischaemic limb in certain structures.
Choosing the right Cuff
To reduce intraoperative and postoperative complications, the appropriate size of tourniquet should be chosen according to the characteristics of the patient, eg size of limb, shape of limb, preexisting conditions, type of surgical procedure. The following is recommended:
A. The widest cuff possible should be chosen. Wide bladders can occlude the blood flow with the use of a lower cuff pressure, thus reducing the risk of injury to the patient.
B. A minimum of two layers of padding should be placed around the extremity as proximal to the surgical skin incision as possible. Cotton-cast padding, sheet padding should not be used due to their shedding of loose fibers/lint that can become embedded in the contact closures with the skin and reduce their effectiveness.
Additionally, studies have shown the best results for the protection of the skin is with the use of an elastic stockinette; the stockinette produces significantly fewer pinches and wrinkles of the skin, as compared to other types of padding, including cast padding.
C. The tourniquet size should be half of the limb diameter.
D. The cuff should overlap between three to six inches. If the overlap is more than six inches, rolling and wrinkling of the underlying skin and increased pressure in the area of the overlap may occur.
E. The choice of size of tourniquet should allow placement of two fingers between the cast padding and the cuff.
F. The choice of using a contour cuff may be optimal in particular patient situations. Contour cuffs occlude the flow of blood at lower pressures than straight cuffs that are of the same width. Contour cuffs are recommended when the extremity is particularly muscular and for use on obese patients to avoid the risk of shearing.
” Always use contoured cuffs of appropriate size especially in conical limbs”
In a study by Distefano et al using impedance plethysmography it was found that the maximal decrease in limb volume by elevation at 45 degrees occurred after 15–20 seconds, with no noticeable change thereafter. For the maximal effect it was suggested that the upper limb should be elevated at 90 degrees; for the lower limb 45 degrees of elevation, since further elevation was likely to kink the femoral vein due to the flexion of the hip.
External compression in addition to elevation has been shown to improve the degree of exsanguinations. It is however contraindicated in patients who have a suspected infected or malignant lesion. The use of an Esmarch bandage or manual exsanguination are more effective than elevation alone. Usage of Esmarch bandage is time-consuming and can damage the skin over a fracture or the atrophic skin of a patient with rheumatoid arthritis . It can also detach pre-existing venous thromboses and produce pulmonary emboli. The need for control of the pressure that is applied has led to the development of appliances such as the Rhys-Davies Exsanguinator. This is an inflated elastic cylinder that is rolled on to the limb. As the exsanguinator is applied, the pressure within the sleeve increases. External methods of exsanguination reduce limb volume by forcing blood from it.
” Use Rhys Davis Exsanguinator and avoid use of Eschmarc bandage “
“Limb occlusion pressure (LOP)” can be defined as the minimum pressure required, at a specific time in a specific tourniquet cuff applied to a specific patient’s limb at a specific location, to stop the flow of arterial blood into the limb distal to the cuff.
Basing tourniquet pressure settings on LOP is better than older methods of fixed pressure levels, or based on a patient’s systolic blood pressure. Setting tourniquet pressure to standard levels will generally be too high or too low it is known that high pressure is associated with a higher probability of nerve injury and other soft tissue injuries, and under-pressurization is associated with the leakage of arterial blood distally and anesthetic agent proximally in Bier block procedures. Setting tourniquet pressure at fixed value above pre-operative systolic blood pressure is inadequate, as it does not take into account adjustments that must be made due to differing cuff widths, cuff shape and limb shape, and amount of tissue below the cuff. Setting tourniquet pressure as a function of LOP inherently takes into account all of these variables.
LOP can be measured in two ways for a specific cuff applied to a specific limb at a specific limb location. Cuff pressure can be increased slowly from zero while monitoring the pulse in an artery distal to the cuff until the distal pulse disappears the lowest cuff pressure at which the pulse disappears can be defined as the ascending LOP. Second, cuff pressure can be decreased slowly (1mmHg/s) from a high occlusive level while monitoring an artery distal to the cuff until a distal pulse resumes the highest pressure at which pulsatile flow first resumes can be defined as the descending LOP. The mean of the ascending and descending LOP can be used as an estimate of the true LOP.
Monitoring of the distal pulse can be done conveniently by palpation, Doppler ultrasound or photoplethysmography (such as a pulse oximeter sensor). Automatic monitoring of the distal pulse and automatic estimation of the LOP by tourniquet instrumentation may save time and improve the consistency of LOP estimates.
The currently established guideline for setting tourniquet pressure based on LOP is as follows:
1) For single-bladder tourniquet cuffs of any width applied to upper limb of an adult, tourniquet pressure should be set at LOP + 40 mmHg for LOP levels less than 130 mmHg, LOP + 60 mmHg for LOP levels between 131 – 190 mmHg, and LOP + 80 mmHg for LOP levels greater than 190 mmHg.
2) For single-bladder tourniquet cuffs of any width applied to the lower limb of an adult, tourniquet pressure should be set at LOP plus 75 mmHg.
” Practice of standard tourniquet pressure of 250mm for upper limb and 300mm for lower limb must be abandoned and pressure should be based on Limb occlusion pressure. For Upper limb LOP+ 50mm and lower limb LOP+75mm Hg are recomended”
Ischaemic Preconditioning of Skeletal Muscle
Ischaemic preconditioning is a process by which exposure of a tissue to a short period of (non-damaging) ischaemic stress leads to resistance to the deleterious effects of a subsequent prolonged ischaemic stress. Exposure of the hind limb to a five-minute period of ischemia and a five-minute period of reperfusion significantly protected the tibialis anterior muscle against the structural damage induced by a subsequent period of four hours of limb ischemia and one hour of reperfusion.
The use of breathing periods can now be abandoned and replaced by perioperative pharmacological protection such as intravenous adenosine but further studies are required.
” There is enough proof to abandon the rebreathing period after every 60min tourniquet application as it further causes reperfusion injury. Instead the ischemic Preconditioning by applying tourniquet for 5min deflate it for 5 min then reapply for prolonged period upto 3 hrs is recomended”
” The Tourniquet may be deflated after the closure of wound. Also there is evidence to show that instead of abruptly deflating the tourniquet, The tourniquet must be deflated and reinflated after 3 min and kept in place for 5min before finally deflating and removing it. This helps in systemic adjustment and avoids pulmonary complications.”
Damage to Nerves
The incidence of peripheral nerve lesions reported are one in 5000 for the arm and one in 13 000 for the leg. The arm palsies are of two main groups: the largest group involved median, ulnar and radial nerves below the tourniquet, while the slightly smaller group comprised isolated radial nerve lesions. The injuries occurred with both Esmarch bandages and pneumatic cuffs. Majority patients have full recovery. The approximate time for recovery was four to five months, although most palsies were transient and others required up to 12 months to disappear. Larger fibres are most susceptible to pressure. There is relative sparing of sensory nerves compared with motor nerves. Small diameter fibres are spared preserving pain and temperature sensation and autonomic function. Because of the localised pathology most palcies heal spontaneously in less than six months and permanent deficits are rare.
Tourniquet paralysis may result from both excessive or insufficient pressure, but the insufficient pressure is considered more dangerous, resulting in passive congestion with possible irreversible functional loss. Persons with lax, loose skin (e.g., the elderly), or persons with large amounts of subcutaneoustissue in cone – shaped limbs are subject to nerve and tissue injury from a shearing force created by an improperly fitting cuff. Most often, shearing occurs at the proximal edge of the cuff. Risk of shearing – related injury may be reduced by selecting a contoured cuff (which fits the limb taper) and a matching limb protection sleeve.
Damage to Skin
Burns occur when the padding under the tourniquet becomes soaked by the antiseptic solution used to paint the skin. Aqueous solutions are not known to cause burns. Antibacterial agents are not responsible for complications except in specific allergic reactions which are rare. Alcohol-based solutions appear to be the most likely cause. The burns are due to prolonged contact of alcohol-based solutions since evaporation is prevented under the tourniquet. Care must be taken to prevent burns. The skin preparation should be applied well distally to the tourniquet in operations below the knee or elbow. Solutions should not be applied too liberally as this promotes spillage and trickling towards the tourniquet.
Should You Use Elastic tourniquets ?
Related hazards and limitations associated with recent efforts to re-introduce a non-pneumatic elastic ring as a tourniquet include the following.
1. The Hemaclear elastic ring does not measure the actual tourniquet pressure applied to the limb, nor does it measure the pressure gradient applied to the patient’s limb.
2. Thus a Hemaclear ring cannot provide the user with an accurate indication of the actual tourniquet pressure and pressure gradient applied to the patient’s limb.
3. There is no documented evidence of the actual pressure levels and pressure gradients applied to limbs by each size of Hemaclear elastic rings.
4. It is not possible to control the pressure applied by the Hemaclear elastic ring to the patient’s limb during a surgical procedure.
5. The surgical user is left with no practical contingency plan in the event of arterial bleeding in the limb distal to the Hemaclear ring during surgery, other than finding and cutting off the ring, and then using a pneumatic tourniquet.
6. Use of a Hemaclear elastic ring is impractical if there is a need for reperfusion of the limb during a long procedure that is typical of revision surgery.
7. Although the Hemaclear elastic ring has had very limited usage in to date, problems and hazards associated with this limited usage have already been reported to the FDA. For example: Report of Severe Pain and Report of Skin Tearing.
” Though Hemaclear is easy to apply the current evidence and cost involved we recommend caution against the use of Hemaclear”