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Procedures under tourniquet
ORTHOPAEDIC ANAESTHESIA
Procedures under tourniquet
Learning objectives
Silky Wong After reading this article, you should be able to: C know how to correctly apply the tourniquet C list out the physiological effects associated with the use of tourniquet C name the complications associated with the use of tourniquet
Michael G Irwin
Abstract Limb tourniquets are commonly used to help facilitate surgery by producing less blood in the surgical field. This may also shorten operative time and reduce intraoperative blood loss. These advantages need to be weighed against potential complications such as post-tourniquet syndrome, skin damage, deep vein thrombosis, rhabdomyolysis and ischaemic pain. Physiological changes in the cardiovascular, respiratory, metabolic, haematological and neurological systems also occur.
Passive method: this is done by raising the upper limb by 90 or the lower limb by 45 Active method: winding an elasticated Esmarch bandage from distal to proximal or by hand-over-hand manual exsanguination. Active exsanguination is more effective than elevation alone, but it is contraindicated in patients with infection, painful fractures being managed with intravenous regional anaesthesia (IVRA) or malignancy.
Keywords Deep vein thrombosis; pathophysiology; post-tourniquet syndrome; tourniquet; tourniquet pain
Tourniquet pressure In the past, the recommended pressures were 75e100 mmHg above systolic blood pressure for the upper limb and 100e150 mmHg above systolic pressure for lower limb surgeries. Others used a standard pressure of 200e250 mmHg for the upper and 250e300 mmHg for the lower limb. The Association of Perioperative Registered Nurses (AORN) has recently recommended using the limb occlusion pressure (measured by gradually increasing tourniquet pressure until distal blood flow is interrupted) with a safety margin of 40 mmHg for limb occlusion pressures of less than 130 mmHg, 60 mmHg for those of 131e190 mmHg and 80 mmHg for those of more than 190 mmHg.2 Tourniquet pressures should be lower in children, although at the moment there are no guidelines as to what pressures should be used. AORN has suggested adding 50 mmHg to limb occlusion pressure for children. With IVRA (e.g. Bier’s block), it is necessary to use double tourniquet cuffs to improve safety and patient comfort. As the
Introduction Tourniquets have been applied to the upper and lower extremities for over 100 years to improve visualization of the operative field and to reduce intraoperative blood loss. Although simple and easy to apply, their use is associated with a number of potential problems.
Applying the tourniquet The diameter of the cuff should be wider than half the diameter of the limb. It is usually applied to the proximal areas of the limb to be operated on, where there is most fat and muscle and where it is reasonably distant from the surgical field (Figure 1). The edges of the cuff must overlap in order to create an even pressure all around the cuff. While padding beneath the tourniquet is recommended, it should not exceed two layers in order to avoid a reduction in the transmitted pressure beneath it.1 Excessive padding decreases the efficacy of the tourniquet and increases the arm circumference. The padding should also be smooth and without crease, because this can cause bullous skin lesions. Ensure that the padding is not soaked in the iodine or alcohol used to prepare the skin prior to surgery to avoid chemical burns. Tourniquet systems should undergo regular checks (Box 1).
Tourniquet inflation Limb exsanguination Before tourniquet inflation, the limb should be exsanguinated. Limbs can be exsanguinated by: Silky Wong MBBS is a Medical Officer in Anaesthesiology at Queen Mary Hospital, Hong Kong, China. Conflicts of interest: none. Michael G Irwin MB ChB MD DA FRCA FANZCA FHKAM is Head of the Department of Anaesthesiology of the University of Hong Kong, China. Conflict of interests: none.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 13:3
Figure 1 Correct application of a tourniquet on the upper thigh with padding.
85
Ó 2011 Elsevier Ltd. All rights reserved.
ORTHOPAEDIC ANAESTHESIA
Routine checking and maintenance of the tourniquet system C C
C
C C
Contraindications to using a tourniquet Absolute contraindications C A limb with an arteriovenous fistula or previous vascular surgery C Malignancy in the operating limb C Peripheral vascular disease
Set up a schedule for regular checks, e.g. every month Visual inspection for damage to the cuff, tubing and machine Turn on the unit. Most tourniquet systems now have selfchecks and automatic calibration After inflating the cuff, check for leaks Do not ignore alarms! Newer systems have audiovisual alarms for air leaks and kinked tubing resulting in deviation from desired pressure
Relative contraindications C History of deep vein thrombosis or pulmonary embolism C Obesity C Rheumatoid arthritis C Severe hypertension C Skin grafts
Box 1 Box 2
diameter of the cuff is narrower, it may be necessary to use higher pressures.
After around 30 minutes of tourniquet inflation, blood pressure and heart rate will start to rise again due to tourniquet pain.
Tourniquet inflation duration There are many different recommendations as to how long a tourniquet can be inflated, but the most widely accepted figure is 2 hours, with 3 hours being the upper safety limit.
After deflation: immediately there will be a transient drop in blood pressure due to the decrease in systemic vascular resistance, release of vasoactive mediators (e.g. adenosine) and myocardial depressant factors from the ischaemic limb. This may be accompanied by an increase in cardiac index. This may then be followed by vasospasm. It is contraindicated to inflate more than one tourniquet at a time as this will cause a significant increase in central venous pressure and may lead to acute cardiac failure and even cardiac arrest. Remote ischaemic preconditioning e remote ischaemic preconditioning (RIPC) is a novel method where ischaemia followed by reperfusion of one organ is believed to protect remote organs either due to release of biochemical messengers in the circulation or activation of nerve pathways, resulting in release of messengers that have a protective effect. In human skeletal muscle, preconditioning has been used for myocardial protection with the beneficial effect being attributed to regulation of endothelial protection, although it’s possible benefit during surgery is not clear.4
Tourniquet deflation Some advocate early release of the tourniquet to achieve haemostasis before wound closure. Studies mainly looking at knee arthroplasty have shown that this practice increases perioperative blood loss.2,3 With delayed tourniquet release, a closed wound with a firmly applied dressing can produce a haemostatic effect during the initial reactive hyperaemia that occurs just after the deflation. However, with delayed tourniquet release, there is an increased risk of other complications. These include delayed detection of major arterial injury such as direct trauma or thrombosis and inadequate control of subcutaneous bleeding leading to haematoma formation. This may increase the risks of wound dehiscence, infection and patellar tracking in the case of knee arthroplasty.3 Contraindications to use of a tourniquet are shown in Box 2.
Temperature Inflation: the limb with the inflated tourniquet will gradually decrease in temperature and may reach room temperature.
Physiological effects of tourniquet inflation Metabolic Within 8 minutes of inflating the tourniquet, anaerobic metabolism begins, resulting in cellular acidosis. Cellular hypoxia and hypercapnia leads to release of myoglobin, intracellular enzymes, adenosine and potassium. On release of the tourniquet, there will be rise in serum potassium and lactate levels and an increase in PaCO2 with subsequent acidosis, with the rise in serum potassium levels peaking at 3 minutes after deflation.
After deflation: during reperfusion of the ischaemic tissues, the core body temperature may drop by up to 0.6 C for each hour that the tourniquet was inflated. Haematological Tourniquet inflation and pain results in systemic hypercoagulation. Significantly higher levels of prothrombin fragment F1.2, plasmin antiplasmin complex and D-dimer have been shown after tourniquet deflation compared to the control leg.5
Cardiovascular On inflation: there is approximately a 15% increase in blood volume and up to 20% increase in systemic vascular resistance after tourniquet inflation. This leads to a rise in blood and central venous pressures which usually dissipate within 5 minutes.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 13:3
Respiratory Lactate release and metabolic acidosis after deflation of the tourniquet raises end tidal carbon dioxide tension by 0.1e2.4
86
Ó 2011 Elsevier Ltd. All rights reserved.
ORTHOPAEDIC ANAESTHESIA
kPa. The rise in end tidal carbon dioxide returns to baseline levels within 10e13 minutes.
function returns to normal within 6 hours. If longer than 3 hours, recovery may take 1e2 weeks.2,6
Complications associated with the use of tourniquets (Box 3)
Systemic effects Pulmonary embolism and deep vein thrombosis: deep vein thrombosis with consequent pulmonary embolism is a major cause of mortality post orthopaedic surgery, especially knee or hip replacements. Virchow’s triad states that there is increased risk of thrombosis with: hypercoagulability haemodynamic changes such as stasis or turbulence endothelial injury. All occur in patients who have had a tourniquet used during their operations.7 In knee replacement surgery, a study on rheumatoid arthritis patients reported a deep vein thrombosis incidence of 15.7% in patients with tourniquet, versus 5.6% of patients in the no tourniquet group.15 For incidence of pulmonary embolism, another study has reported 7.1% in unilateral total knee arthroplasty with tourniquet, and 0% without tourniquet. The same study has reported pulmonary embolism of 40% in bilateral total knee arthroplasty with tourniquet and 7.1% without tourniquet.16
Local effects Local effects of using the tourniquet are mainly related to either the pressure generated by the cuff or to the duration of ischaemia. Skin damage: skin damage, either bruising from prolonged tourniquet pressure, from creasing of the padding layer or from padding getting soaked with disinfectant. Prolonged oedema: if this oedema is severe from prolonged inflation of the tourniquet, this might make closing of wounds difficult. Tourniquet induced neuropathy: post-tourniquet syndrome: this is a common cause of morbidity caused by injury to both the motor and sensory fibres of the mixed peripheral nerve. Patients present with motor loss and diminished touch, vibration and position sense. The larger motor fibres are more susceptible to ischaemic injury than the smaller, more central sensory fibres. Tourniquets cause nerve damage either by ischaemia or mechanical deformation. Prolonged nerve dysfunction is caused by compression of the nerve under the edges of the cuff, where the mechanical distortion of the nerve is maximal and the node of Ranvier is displaced from its usual position under the Schwann-cell junction. At the cellular level, irreversible damage is caused by distortion of the myelin lamellae and axonal shrinkage. This mainly affects neurons of larger diameter. Ischaemia causes metabolic stress to the neurons. This results in depolarization and generation of spontaneous activity, then later, blockade of slow conducting fibres, and later all neurons. If the subject was not anaesthetized, this would be perceived as paraesthesia. If ischaemic time is less than 2 hours, nerve
Tourniquet pain and tourniquet hypertension: tourniquet pain and hypertension is a poorly understood phenomenon. It is more a more common occurrence in patients under general anaesthesia than regional anaesthesia. After 1 hour of tourniquet inflation, patients under spinal or epidural anaesthesia may start to perceive a dull aching pain and become hypertensive. Patients under general anaesthesia will have a gradual rise in blood pressure starting 30 minutes after tourniquet inflation. This is due to tourniquet pain. Giving intravenous opioids will not be able to relieve the tourniquet pain, nor will deepening of anaesthesia. To control the rise in blood pressure, it may be necessary to give intravenous anti-hypertensive agents such as labetalol. Tourniquet pain may be relieved by deflating the cuff for 10e15 minutes. Some studies have shown that this is correlated to correction of cellular acidosis. In spinal anaesthesia, there is a higher incidence of tourniquet pain with hyperbaric than isobaric bupivacaine, suggesting that a more intense block will lessen tourniquet pain because hyperbaric bupivacaine tends to give an incomplete subarachnoid distribution. A study in awake patients found that tourniquet pain becomes unbearable after around 31 minutes. Sedation and analgesia prolonged this to around 45 minutes. Applying Emla cream increased tolerance of pain to 46.4 minutes.8
Complications associated with use of tourniquets Local effects C Skin damage C Paraesthesia, neuralgia, muscle weakness C Post-tourniquet syndrome C Compartment syndrome C Delayed wound healing, wound infection C Oedema
Rhabdomyolysis: tourniquet induced rhabdomyolysis is caused by vascular occlusion and skeletal muscle ischaemia. This is a rare complication and the few case reports have all noted a tourniquet application time of more than 4 hours. In one of the cases, the tourniquet pressure was too high (520 mmHg). Clinicians should adhere to recommendations on tourniquet inflation duration and pressure, as the critical ischaemia period in skeletal muscle is around 2.5 hours.9,10 Some have suggested intermittent cuff deflation, but there is currently no evidence that this will decrease complication rates.
Systemic effects C Pulmonary embolism C Deep vein thrombosis C Tourniquet pain and hypertension C Rhabdomyolysis C Pulmonary oedema C Cardiac arrest
Box 3
ANAESTHESIA AND INTENSIVE CARE MEDICINE 13:3
87
Ó 2011 Elsevier Ltd. All rights reserved.
ORTHOPAEDIC ANAESTHESIA
Tourniquet use in different surgical sites
3 Rama KRBS, Apsingi S, Poovali S, Jetti A. Timing of tourniquet release in knee arthroplasty. J Bone Joint Surg Am 2007; 89: 699e705. 4 Kharbanda RK, Mortensen UM, White PA, et al. Transient limb ischemia induces remote ischemic preconditioning in vivo. Circulation 2002; 106: 2881. 5 Reikeras O, Clementsen T. Time course of thrombosis and fibrinolysis in total knee arthroplasty with tourniquet application. Local versus systemic activations. J Thromb Thrombolysis 2009; 28: 425e8. 6 Hogan QH. Pathophysiology of peripheral nerve injury during regional anesthesia. Reg Anesth Pain Med 2008; 33: 435e41. 7 Smith TO, Hing CB. Is a tourniquet beneficial in total knee replacement surgery? A meta-analysis and systemic review. Knee 2010; 10: 141e7. 8 Gielen MJM, Stienstra R. Tourniquet hypertension and its prevention: a review. Reg Anesth 1991; 16: 191e4. 9 Lee YG, Park W, Kim SH, et al. A case of rhabdomyolysis associated with use of a pneumatic tourniquet during arthroscopic knee surgery. Korean J Intern Med 2010; 25: 105e9. 10 Eckert P, Schnackerz K. Ischemic tolerance of human skeletal muscle. Ann Plast Surg 1991; 26: 77. 11 Saied A, Zyaei A. Tourniquet use during plating of acute extraarticular tibial fractures: effects on final results of the operation. J Trauma 2010; 69: E94e7. 12 Smith TO, Hing CB. A meta-analysis of tourniquet assisted arthroscopic knee surgery. Knee 2009; 16: 317e21. 13 Smith TO, Hing CB. The efficacy of tourniquet in foot and ankle surgery? A systematic review and meta-analysis. Foot Ankle Surg 2010; 16: 3e8. 14 Karalezli N, Ogun CO, Ogun TC, Yildirim S, Tuncay I. Wrist tourniquet: the most patient-friendly way of bloodless hand surgery. J Trauma 2007; 62: 750e4. 15 Wauke K, Nagashima M, Kato N, Ogawa R, Yoshino S. Comparative study between thromboembolism and total knee arthroplasty with or without tourniquet in rheumatoid arthritis patients. Arch Orthop Trauma Surg 2002; 122: 442e6. 16 Nishiguchi M, takamura N, Abe Y, Kono M, Shindo H, Aoyagi K. Pilot study on the use of tourniquet: a risk factor for pulmonary thromboembolism after total knee arthroplasty? Thromb Res 2005; 115: 271e6.
Although tourniquet use reduces blood loss intraoperatively, it may not reduce total perioperative blood loss. Tourniquet use also seems to increase postoperative pain and there is also a suggestion that it may increase postoperative infection rates.10 In knee surgery, there is evidence that there might not be any substantial advantage in using tourniquet when increased risks of such complications are considered.7,11 In foot and ankle surgeries there has been a study suggesting that, without the use of intraoperative tourniquet, patients had a shorter length of stay, less postoperative pain and reduced swelling. With the tourniquet inflated, there was a greater incidence of wound infections and deep vein thrombosis.12 In hand surgery, there is little evidence available. One study compared the tourniquet placement in different parts of the upper limb for hand surgeries, and found that compared to tourniquet on the arm and forearm, the wrist tourniquet was the best in terms of lower lactate levels, the least pain and longest tolerance to the cuff.13
Conclusion The incidence of tourniquet-related complications is quite low (reported to be 1 in 2442 in Norway),14 but extremely serious. The risk needs to be carefully considered against surgical advantages and guidelines diligently followed. Recent evidence suggests that the use of tourniquets may not be so useful in foot and ankle surgery. A
REFERENCES 1 Raipura A, Somanchi VB, Muir LTSW. The effect of tourniquet padding on the efficiency of tourniquets of the upper limb. J Bone Joint Surg Br 2007; 89-B: 532e4. 2 Noordin S, McEwen JA, Kragh Jr CJF, Eisen A, Masri BA. Surgical tourniquets in orthopedics. J Bone Joint Surg Am 2009; 91: 2958e67.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 13:3
88
Ó 2011 Elsevier Ltd. All rights reserved.
Procedures under tourniquet
Learning objectives
Silky Wong After reading this article, you should be able to: C know how to correctly apply the tourniquet C list out the physiological effects associated with the use of tourniquet C name the complications associated with the use of tourniquet
Michael G Irwin
Abstract Limb tourniquets are commonly used to help facilitate surgery by producing less blood in the surgical field. This may also shorten operative time and reduce intraoperative blood loss. These advantages need to be weighed against potential complications such as post-tourniquet syndrome, skin damage, deep vein thrombosis, rhabdomyolysis and ischaemic pain. Physiological changes in the cardiovascular, respiratory, metabolic, haematological and neurological systems also occur.
Passive method: this is done by raising the upper limb by 90 or the lower limb by 45 Active method: winding an elasticated Esmarch bandage from distal to proximal or by hand-over-hand manual exsanguination. Active exsanguination is more effective than elevation alone, but it is contraindicated in patients with infection, painful fractures being managed with intravenous regional anaesthesia (IVRA) or malignancy.
Keywords Deep vein thrombosis; pathophysiology; post-tourniquet syndrome; tourniquet; tourniquet pain
Tourniquet pressure In the past, the recommended pressures were 75e100 mmHg above systolic blood pressure for the upper limb and 100e150 mmHg above systolic pressure for lower limb surgeries. Others used a standard pressure of 200e250 mmHg for the upper and 250e300 mmHg for the lower limb. The Association of Perioperative Registered Nurses (AORN) has recently recommended using the limb occlusion pressure (measured by gradually increasing tourniquet pressure until distal blood flow is interrupted) with a safety margin of 40 mmHg for limb occlusion pressures of less than 130 mmHg, 60 mmHg for those of 131e190 mmHg and 80 mmHg for those of more than 190 mmHg.2 Tourniquet pressures should be lower in children, although at the moment there are no guidelines as to what pressures should be used. AORN has suggested adding 50 mmHg to limb occlusion pressure for children. With IVRA (e.g. Bier’s block), it is necessary to use double tourniquet cuffs to improve safety and patient comfort. As the
Introduction Tourniquets have been applied to the upper and lower extremities for over 100 years to improve visualization of the operative field and to reduce intraoperative blood loss. Although simple and easy to apply, their use is associated with a number of potential problems.
Applying the tourniquet The diameter of the cuff should be wider than half the diameter of the limb. It is usually applied to the proximal areas of the limb to be operated on, where there is most fat and muscle and where it is reasonably distant from the surgical field (Figure 1). The edges of the cuff must overlap in order to create an even pressure all around the cuff. While padding beneath the tourniquet is recommended, it should not exceed two layers in order to avoid a reduction in the transmitted pressure beneath it.1 Excessive padding decreases the efficacy of the tourniquet and increases the arm circumference. The padding should also be smooth and without crease, because this can cause bullous skin lesions. Ensure that the padding is not soaked in the iodine or alcohol used to prepare the skin prior to surgery to avoid chemical burns. Tourniquet systems should undergo regular checks (Box 1).
Tourniquet inflation Limb exsanguination Before tourniquet inflation, the limb should be exsanguinated. Limbs can be exsanguinated by: Silky Wong MBBS is a Medical Officer in Anaesthesiology at Queen Mary Hospital, Hong Kong, China. Conflicts of interest: none. Michael G Irwin MB ChB MD DA FRCA FANZCA FHKAM is Head of the Department of Anaesthesiology of the University of Hong Kong, China. Conflict of interests: none.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 13:3
Figure 1 Correct application of a tourniquet on the upper thigh with padding.
85
Ó 2011 Elsevier Ltd. All rights reserved.
ORTHOPAEDIC ANAESTHESIA
Routine checking and maintenance of the tourniquet system C C
C
C C
Contraindications to using a tourniquet Absolute contraindications C A limb with an arteriovenous fistula or previous vascular surgery C Malignancy in the operating limb C Peripheral vascular disease
Set up a schedule for regular checks, e.g. every month Visual inspection for damage to the cuff, tubing and machine Turn on the unit. Most tourniquet systems now have selfchecks and automatic calibration After inflating the cuff, check for leaks Do not ignore alarms! Newer systems have audiovisual alarms for air leaks and kinked tubing resulting in deviation from desired pressure
Relative contraindications C History of deep vein thrombosis or pulmonary embolism C Obesity C Rheumatoid arthritis C Severe hypertension C Skin grafts
Box 1 Box 2
diameter of the cuff is narrower, it may be necessary to use higher pressures.
After around 30 minutes of tourniquet inflation, blood pressure and heart rate will start to rise again due to tourniquet pain.
Tourniquet inflation duration There are many different recommendations as to how long a tourniquet can be inflated, but the most widely accepted figure is 2 hours, with 3 hours being the upper safety limit.
After deflation: immediately there will be a transient drop in blood pressure due to the decrease in systemic vascular resistance, release of vasoactive mediators (e.g. adenosine) and myocardial depressant factors from the ischaemic limb. This may be accompanied by an increase in cardiac index. This may then be followed by vasospasm. It is contraindicated to inflate more than one tourniquet at a time as this will cause a significant increase in central venous pressure and may lead to acute cardiac failure and even cardiac arrest. Remote ischaemic preconditioning e remote ischaemic preconditioning (RIPC) is a novel method where ischaemia followed by reperfusion of one organ is believed to protect remote organs either due to release of biochemical messengers in the circulation or activation of nerve pathways, resulting in release of messengers that have a protective effect. In human skeletal muscle, preconditioning has been used for myocardial protection with the beneficial effect being attributed to regulation of endothelial protection, although it’s possible benefit during surgery is not clear.4
Tourniquet deflation Some advocate early release of the tourniquet to achieve haemostasis before wound closure. Studies mainly looking at knee arthroplasty have shown that this practice increases perioperative blood loss.2,3 With delayed tourniquet release, a closed wound with a firmly applied dressing can produce a haemostatic effect during the initial reactive hyperaemia that occurs just after the deflation. However, with delayed tourniquet release, there is an increased risk of other complications. These include delayed detection of major arterial injury such as direct trauma or thrombosis and inadequate control of subcutaneous bleeding leading to haematoma formation. This may increase the risks of wound dehiscence, infection and patellar tracking in the case of knee arthroplasty.3 Contraindications to use of a tourniquet are shown in Box 2.
Temperature Inflation: the limb with the inflated tourniquet will gradually decrease in temperature and may reach room temperature.
Physiological effects of tourniquet inflation Metabolic Within 8 minutes of inflating the tourniquet, anaerobic metabolism begins, resulting in cellular acidosis. Cellular hypoxia and hypercapnia leads to release of myoglobin, intracellular enzymes, adenosine and potassium. On release of the tourniquet, there will be rise in serum potassium and lactate levels and an increase in PaCO2 with subsequent acidosis, with the rise in serum potassium levels peaking at 3 minutes after deflation.
After deflation: during reperfusion of the ischaemic tissues, the core body temperature may drop by up to 0.6 C for each hour that the tourniquet was inflated. Haematological Tourniquet inflation and pain results in systemic hypercoagulation. Significantly higher levels of prothrombin fragment F1.2, plasmin antiplasmin complex and D-dimer have been shown after tourniquet deflation compared to the control leg.5
Cardiovascular On inflation: there is approximately a 15% increase in blood volume and up to 20% increase in systemic vascular resistance after tourniquet inflation. This leads to a rise in blood and central venous pressures which usually dissipate within 5 minutes.
ANAESTHESIA AND INTENSIVE CARE MEDICINE 13:3
Respiratory Lactate release and metabolic acidosis after deflation of the tourniquet raises end tidal carbon dioxide tension by 0.1e2.4
86
Ó 2011 Elsevier Ltd. All rights reserved.
ORTHOPAEDIC ANAESTHESIA
kPa. The rise in end tidal carbon dioxide returns to baseline levels within 10e13 minutes.
function returns to normal within 6 hours. If longer than 3 hours, recovery may take 1e2 weeks.2,6
Complications associated with the use of tourniquets (Box 3)
Systemic effects Pulmonary embolism and deep vein thrombosis: deep vein thrombosis with consequent pulmonary embolism is a major cause of mortality post orthopaedic surgery, especially knee or hip replacements. Virchow’s triad states that there is increased risk of thrombosis with: hypercoagulability haemodynamic changes such as stasis or turbulence endothelial injury. All occur in patients who have had a tourniquet used during their operations.7 In knee replacement surgery, a study on rheumatoid arthritis patients reported a deep vein thrombosis incidence of 15.7% in patients with tourniquet, versus 5.6% of patients in the no tourniquet group.15 For incidence of pulmonary embolism, another study has reported 7.1% in unilateral total knee arthroplasty with tourniquet, and 0% without tourniquet. The same study has reported pulmonary embolism of 40% in bilateral total knee arthroplasty with tourniquet and 7.1% without tourniquet.16
Local effects Local effects of using the tourniquet are mainly related to either the pressure generated by the cuff or to the duration of ischaemia. Skin damage: skin damage, either bruising from prolonged tourniquet pressure, from creasing of the padding layer or from padding getting soaked with disinfectant. Prolonged oedema: if this oedema is severe from prolonged inflation of the tourniquet, this might make closing of wounds difficult. Tourniquet induced neuropathy: post-tourniquet syndrome: this is a common cause of morbidity caused by injury to both the motor and sensory fibres of the mixed peripheral nerve. Patients present with motor loss and diminished touch, vibration and position sense. The larger motor fibres are more susceptible to ischaemic injury than the smaller, more central sensory fibres. Tourniquets cause nerve damage either by ischaemia or mechanical deformation. Prolonged nerve dysfunction is caused by compression of the nerve under the edges of the cuff, where the mechanical distortion of the nerve is maximal and the node of Ranvier is displaced from its usual position under the Schwann-cell junction. At the cellular level, irreversible damage is caused by distortion of the myelin lamellae and axonal shrinkage. This mainly affects neurons of larger diameter. Ischaemia causes metabolic stress to the neurons. This results in depolarization and generation of spontaneous activity, then later, blockade of slow conducting fibres, and later all neurons. If the subject was not anaesthetized, this would be perceived as paraesthesia. If ischaemic time is less than 2 hours, nerve
Tourniquet pain and tourniquet hypertension: tourniquet pain and hypertension is a poorly understood phenomenon. It is more a more common occurrence in patients under general anaesthesia than regional anaesthesia. After 1 hour of tourniquet inflation, patients under spinal or epidural anaesthesia may start to perceive a dull aching pain and become hypertensive. Patients under general anaesthesia will have a gradual rise in blood pressure starting 30 minutes after tourniquet inflation. This is due to tourniquet pain. Giving intravenous opioids will not be able to relieve the tourniquet pain, nor will deepening of anaesthesia. To control the rise in blood pressure, it may be necessary to give intravenous anti-hypertensive agents such as labetalol. Tourniquet pain may be relieved by deflating the cuff for 10e15 minutes. Some studies have shown that this is correlated to correction of cellular acidosis. In spinal anaesthesia, there is a higher incidence of tourniquet pain with hyperbaric than isobaric bupivacaine, suggesting that a more intense block will lessen tourniquet pain because hyperbaric bupivacaine tends to give an incomplete subarachnoid distribution. A study in awake patients found that tourniquet pain becomes unbearable after around 31 minutes. Sedation and analgesia prolonged this to around 45 minutes. Applying Emla cream increased tolerance of pain to 46.4 minutes.8
Complications associated with use of tourniquets Local effects C Skin damage C Paraesthesia, neuralgia, muscle weakness C Post-tourniquet syndrome C Compartment syndrome C Delayed wound healing, wound infection C Oedema
Rhabdomyolysis: tourniquet induced rhabdomyolysis is caused by vascular occlusion and skeletal muscle ischaemia. This is a rare complication and the few case reports have all noted a tourniquet application time of more than 4 hours. In one of the cases, the tourniquet pressure was too high (520 mmHg). Clinicians should adhere to recommendations on tourniquet inflation duration and pressure, as the critical ischaemia period in skeletal muscle is around 2.5 hours.9,10 Some have suggested intermittent cuff deflation, but there is currently no evidence that this will decrease complication rates.
Systemic effects C Pulmonary embolism C Deep vein thrombosis C Tourniquet pain and hypertension C Rhabdomyolysis C Pulmonary oedema C Cardiac arrest
Box 3
ANAESTHESIA AND INTENSIVE CARE MEDICINE 13:3
87
Ó 2011 Elsevier Ltd. All rights reserved.
ORTHOPAEDIC ANAESTHESIA
Tourniquet use in different surgical sites
3 Rama KRBS, Apsingi S, Poovali S, Jetti A. Timing of tourniquet release in knee arthroplasty. J Bone Joint Surg Am 2007; 89: 699e705. 4 Kharbanda RK, Mortensen UM, White PA, et al. Transient limb ischemia induces remote ischemic preconditioning in vivo. Circulation 2002; 106: 2881. 5 Reikeras O, Clementsen T. Time course of thrombosis and fibrinolysis in total knee arthroplasty with tourniquet application. Local versus systemic activations. J Thromb Thrombolysis 2009; 28: 425e8. 6 Hogan QH. Pathophysiology of peripheral nerve injury during regional anesthesia. Reg Anesth Pain Med 2008; 33: 435e41. 7 Smith TO, Hing CB. Is a tourniquet beneficial in total knee replacement surgery? A meta-analysis and systemic review. Knee 2010; 10: 141e7. 8 Gielen MJM, Stienstra R. Tourniquet hypertension and its prevention: a review. Reg Anesth 1991; 16: 191e4. 9 Lee YG, Park W, Kim SH, et al. A case of rhabdomyolysis associated with use of a pneumatic tourniquet during arthroscopic knee surgery. Korean J Intern Med 2010; 25: 105e9. 10 Eckert P, Schnackerz K. Ischemic tolerance of human skeletal muscle. Ann Plast Surg 1991; 26: 77. 11 Saied A, Zyaei A. Tourniquet use during plating of acute extraarticular tibial fractures: effects on final results of the operation. J Trauma 2010; 69: E94e7. 12 Smith TO, Hing CB. A meta-analysis of tourniquet assisted arthroscopic knee surgery. Knee 2009; 16: 317e21. 13 Smith TO, Hing CB. The efficacy of tourniquet in foot and ankle surgery? A systematic review and meta-analysis. Foot Ankle Surg 2010; 16: 3e8. 14 Karalezli N, Ogun CO, Ogun TC, Yildirim S, Tuncay I. Wrist tourniquet: the most patient-friendly way of bloodless hand surgery. J Trauma 2007; 62: 750e4. 15 Wauke K, Nagashima M, Kato N, Ogawa R, Yoshino S. Comparative study between thromboembolism and total knee arthroplasty with or without tourniquet in rheumatoid arthritis patients. Arch Orthop Trauma Surg 2002; 122: 442e6. 16 Nishiguchi M, takamura N, Abe Y, Kono M, Shindo H, Aoyagi K. Pilot study on the use of tourniquet: a risk factor for pulmonary thromboembolism after total knee arthroplasty? Thromb Res 2005; 115: 271e6.
Although tourniquet use reduces blood loss intraoperatively, it may not reduce total perioperative blood loss. Tourniquet use also seems to increase postoperative pain and there is also a suggestion that it may increase postoperative infection rates.10 In knee surgery, there is evidence that there might not be any substantial advantage in using tourniquet when increased risks of such complications are considered.7,11 In foot and ankle surgeries there has been a study suggesting that, without the use of intraoperative tourniquet, patients had a shorter length of stay, less postoperative pain and reduced swelling. With the tourniquet inflated, there was a greater incidence of wound infections and deep vein thrombosis.12 In hand surgery, there is little evidence available. One study compared the tourniquet placement in different parts of the upper limb for hand surgeries, and found that compared to tourniquet on the arm and forearm, the wrist tourniquet was the best in terms of lower lactate levels, the least pain and longest tolerance to the cuff.13
Conclusion The incidence of tourniquet-related complications is quite low (reported to be 1 in 2442 in Norway),14 but extremely serious. The risk needs to be carefully considered against surgical advantages and guidelines diligently followed. Recent evidence suggests that the use of tourniquets may not be so useful in foot and ankle surgery. A
REFERENCES 1 Raipura A, Somanchi VB, Muir LTSW. The effect of tourniquet padding on the efficiency of tourniquets of the upper limb. J Bone Joint Surg Br 2007; 89-B: 532e4. 2 Noordin S, McEwen JA, Kragh Jr CJF, Eisen A, Masri BA. Surgical tourniquets in orthopedics. J Bone Joint Surg Am 2009; 91: 2958e67.
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