no protective material was used in the third group (n = 30). A140-mm-wide contoured cuff or a 100-mm-wide cylindricalcuff was applied at the discretion of the surgical nurse. Cuffpressure, which was determined by the surgeon, was recom-mended to be 70 to 100 mm Hg above the patient’s systolicblood pressure for the contoured cuffs and 100 to 150 mm Hgabove the systolic blood pressure for the cylindrical cuffs. Thetwo groups with skin protection had fewer skin injuries (p =0.007), and no patient who received the elastic stockinette hadblisters. Skin blisters developed beneath the pneumatic tour-niquet in ten patients—seven in the no-tourniquet-paddinggroup and three in the cast-padding group. The duration of thebloodless field was longer for the patients with blisters than itwas for those without blisters (mean and standard deviation,112 ± 29 and 94 ± 21 minutes, respectively; p = 0.04). Therewere no significant differences in cuff pressure, thigh cir-cumference, or age between the patients in whom blistersdeveloped and those in whom they did not.

Tredwell et al.41 quantitatively analyzed wrinkling andpinching of the skin at the cuff-limb interface in a study ofchildren. In a series of forty-four trials on the upper arms andthighs of two healthy child volunteers, tourniquet cuffs withdual-layer stockinette limb-protection sleeves in sizes matchedto the specific cuffs significantly reduced (p < 0.01) the

quantity and maximum height of skin wrinkling when com-pared with values associated with other forms of limb pro-tection. In a study involving a total of fifty-five trials of fivedifferent types of limb protection beneath tourniquet cuffs onthe upper limbs and thighs of five adults, it was found thatstretched sleeves made of two-layer tubular elastic material andmatched to the specific tourniquet cuffs produced significantlyfewer, less severe pinches and wrinkles in the skin surface ascompared with all other types of limb protection tested(maximum p < 0.01)42.

Duration of Tourniquet UseTourniquet-related complications increase as tourniquet timeincreases43-45. Because there is no completely safe tourniquettime, the concept of accurately monitoring and minimizingtourniquet time to minimize the risk of injury is commonlyaccepted in surgical, military, and pre-hospital settings. Exper-imental data have demonstrated that the severity of tourniquetischemia is dependent not only on tourniquet time but also ontissue type. Serum creatine phosphokinase concentration is el-evated in response to muscle damage at and distal to the tour-niquet cuff. Furthermore, interruption of blood supply resultsin cellular hypoxia, tissue acidosis, and potassium release39,which, on reperfusion, are eventually corrected in the systemic

Fig. 5

A comparison of applied pressures and pressure gradients typically produced by a modern pneumatic surgical tourniquet cuff (A); a non-

pneumatic, non-elastic, belt-type military tourniquet designed for self-application on the battlefield (B); and a non-pneumatic ring made of

elastic material, designed to be rolled from a distal location to a proximal location on a limb and to remain there for surgery, thereby

combining exsanguination and tourniquet functions (C). Each tourniquet was selected and applied as recommended by the respective

manufacturer to stop arterial blood flow in an upper limb. Higher levels of pressure and higher pressure gradients are associated with higher

probabilities of patient injuries6.

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circulation. Although we are not aware of any prospectiverandomized clinical trial that has defined the optimal durationof tourniquet use in lower-limb surgery, two hours is consid-ered to be relatively safe for upper-limb surgery 9. This isconsistent with the findings of a study of lower-extremitysurgery by Ostman et al.46, who used microdialysis to charac-terize the time course and metabolite levels in skeletal muscleexposed to ischemia and reperfusion in eight patients un-dergoing arthroscopic-assisted anterior cruciate ligament re-construction. The ischemia-induced energy metabolic change inthe rectus femoris muscle in these patients had almost com-pletely disappeared within two hours after tourniquet deflation.

One way of avoiding ischemic injury to muscle cells maybe to employ a so-called tourniquet downtime technique, inwhich the tourniquet is released for a short period and then isreinflated. However, there is no evidence to support use of thistechnique, the suggested reperfusion time between successiveischemic periods has ranged from three to twenty minutes47,and time limits for subsequent ischemia are unknown. Fur-thermore, some authors have questioned the benefit of anytourniquet release and reinflation if the total tourniquet timedoes not exceed three hours48. In view of this controversy andin the absence of convincing evidence otherwise, we do notrecommend a routine tourniquet inflation time of more thantwo hours. Accurate monitoring and minimization of tourni-quet time are recommended.

Tourniquet DeflationDeflation and reperfusion permit replenishment of energysupplies and elimination of toxic metabolites. However, carefulmonitoring of the patient is essential at this stage of the oper-ation, as pulmonary embolization may occur49. Despite thesubstantial risk of postoperative deep venous thrombosis inorthopaedic extremity surgery, use of a pneumatic tourniquetdoes not appear to be an independent risk factor50. In the settingof intramedullary instrumentation, cementation, or insertion ofa prosthesis in the lower limb, deflation of a pneumatic tour-niquet adds the risk of a sudden release of large venous emboli,emphasizing the need for careful patient monitoring at thattime49. The return of toxic metabolites to the circulation resultsin systemic metabolic dysfunction, referred to as ‘‘myoneph-ropathic metabolic syndrome’’ and characterized by metabolicacidosis, hyperkalemia, myoglobulinemia, myoglobinuria, andrenal failure9. Paradoxically, tourniquet deflation is associatedwith thrombolytic activity, anoxia promoting activation of theantithrombin-III and protein-C pathways, which may be im-plicated in post-tourniquet bleeding.

Tourniquet deflation prior to wound closure in kneearthroplasty is associated with greater blood loss and a higherdemand for blood transfusion, suggesting that release follow-ing wound closure would offer better control51. Rama et al.52

examined the time of tourniquet release in a meta-analysis ofeleven randomized controlled trials involving a total of 872patients and 893 primary knee arthroplasties. They found thatearly release of the tourniquet to achieve hemostasis increasedperioperative blood loss in association with primary knee ar-

throplasty. However, the risk of a complication requiringadditional operative treatment was increased when the tour-niquet was left inflated until wound closure was complete.Overall, the surgeon has to balance the potential downside ofdelayed deflation (namely, increased bleeding) with the risks ofprolonging tourniquet inflation times. The final decision re-garding when to deflate the tourniquet should be made by thesurgeon, after weighing the risks and benefits of delayingtourniquet deflation until closure is complete.

Future DirectionsThe concept of measuring limb occlusion pressure immedi-ately prior to inflation of a surgical tourniquet establishesa basis for setting the optimal tourniquet pressure for eachpatient. However, a single measurement represents a staticlimb occlusion pressure to which a margin of safety must beadded to account for relevant intraoperative variations in thepatient’s physiology during an operation. In the future, safertourniquet systems using lower tourniquet pressures couldperhaps be developed by monitoring those physiologic varia-tions intraoperatively and estimating a dynamic limb occlusionpressure on the basis of those variations and the static limbocclusion pressure, thus eliminating the need to increase thestatic limb occlusion pressure by an arbitrary predeterminedmargin of safety8,28,53,54.

The risk of tourniquet-related nerve injuries and par-ticularly the increased risk of such injuries as tourniquetpressure levels rise, as pressure gradients under cuffs increase,and as tourniquet time increases are well established. To a largeextent, this is addressed in surgical practice by minimizingtourniquet time, by new technology that helps to minimize thetourniquet pressures that are required, and by new types ofpneumatic tourniquet cuffs that help to minimize cuff pressurelevels and gradients. Given the increasing rate of obesity, newdesigns of tourniquet cuffs that allow arterial blood flow to bestopped effectively at the lowest possible tourniquet pressuresand gradients may be helpful for the increasing numbers ofobese patients. Additionally, recent studies suggest that in thefuture it may be feasible to further reduce the risk of neuro-logical injuries by directly monitoring axonal excitability innerves beneath tourniquet cuffs55,56. This may allow surgicalstaff to be alerted promptly to potential nerve-related hazardsbefore injury occurs.

A futuristic concept for further increasing tourniquetsafety and effectiveness in orthopaedic surgery may arise froma current military project. The (U.S.) Defense Advanced Re-search Projects Agency (DARPA) is sponsoring the DeepBleeder Acoustic Coagulation (DBAC) program with the goalof developing a noninvasive, automated ultrasonic system forthe detection, localization, and coagulation of deep bleedingvessels that is operable by minimally trained personnel in thecombat environment57. A spin-off benefit of the DARPA DBACprogram might be the development of low-cost ultrasonicsensor arrays that could be useful for accurately detecting,monitoring, and controlling the occlusion of arterial bloodflow beneath surgical tourniquet cuffs.

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In the future, to further improve tourniquet safety, ef-ficacy, and reliability, the development and evaluation of sur-gical tourniquets, military tourniquets, and new pre-hospitaltourniquets for both civilian and military applications will beintertwined, and an improved exchange of information abouttechniques, technology, and outcomes will be possible. nNOTE: The authors acknowledge Daphne Savoy for her assistance in the preparation of thismanuscript.

Shahryar Noordin, MBBS, FCPSSection of Orthopaedics,Department of Surgery,Aga Khan University, Stadium Road,P.O. Box 3500, Karachi 74800, Pakistan.E-mail address: shahryar.noordin@aku.edu

James A. McEwen, PhD, PEngBassam A. Masri, MD, FRCSCDivision of Lower Limb Reconstruction and Oncology,Department of Orthopaedics (J.A.McE., and B.A.M.), andDepartment of Electrical and Computer Engineering (J.A.McE.),University of British Columbia,3114, 910 West 10th Avenue, Vancouver, V5Z 4E3 BC, Canada

Colonel John F. Kragh Jr., MDUnited States Army Institute of Surgical Research,Regenerative Medicine,3400 Rawley East Chambers Avenue, Building 3611,Room L82-16, Fort Sam Houston, TX 78234-6315

Andrew Eisen, MD, FRCPCDepartment of Neurology,University of British Columbia, 2862 Highbury Street,Vancouver, V6R 3T6 BC, Canada

References

1. Klenerman L. The tourniquet in surgery. J Bone Joint Surg Br. 1962;44:937-43.

2. Lister JB. Collected papers. Vol 1. Oxford: Clarendon Press; 1909. p 176.

3. von Esmarch F. First aid to the injured: six ambulance lectures. HRH PrincessChristian, translator. 6th ed. London: Smith, Elder and Co; 1898.

4. Cushing H. Pneumatic tourniquets: with special reference to their use in cra-niotomies. Med. News. 1904;84:557.

5. Murphy CG, Winter DC, Bouchier-Hayes DJ. Tourniquet injuries: pathogenesisand modalities for attenuation. Acta Orthop Belg. 2005;71:635-45.

6. McEwen J, Casey V. Measurement of hazardous pressure levels and gradientsproduced on human limbs by non-pneumatic tourniquets. In: Proceedings of the32nd Conference of the Canadian Medical and Biological Engineering Society2009. Calgary, Canada; 2009 May 20-22. p 1-4.

7. McEwen JA. Complications of and improvements in pneumatic tourniquets usedin surgery. Med Instrum. 1981;15:253-7.

8. Elements of a modern tourniquet system. http://www.tourniquets.org/tourniquet_technology.php

9. Wakai A, Winter DC, Street JT, Redmond PH. Pneumatic tourniquets in extremitysurgery. J Am Acad Orthop Surg. 2001;9:345-51.

10. McGraw RW, McEwen JA. The tourniquet. In: McFarlane RM, editor. Un-satisfactory results in hand surgery. New York: Churchill Livingstone; 1987. p 5-13.

11. Weingarden SI, Louis DL, Waylonis GW. Electromyographic changes in post-meniscectomy patients. Role of the pneumatic tourniquet. JAMA. 1979;241:1248-50.

12. Dobner JJ, Nitz AJ. Postmeniscectomy tourniquet palsy and functional se-quelae. Am J Sports Med. 1982;10:211-4.

13. Nitz AJ, Dobner JJ. Upper extremity tourniquet effects in carpal tunnel release.J Hand Surg Am. 1989;14:499-504.

14. Mohler LR, Pedowitz RA, Myers RR, Ohara WM, Lopez MA, Gershuni DH. In-termittent reperfusion fails to prevent posttourniquet neurapraxia. J Hand Surg Am.1999;24:687-93.

15. Odinsson A, Finsen V. Tourniquet use and its complications in Norway. J BoneJoint Surg Br. 2006;88:1090-2.

16. Middleton RW, Varian JP. Tourniquet paralysis. Aust N Z J Surg. 1974;44:124-8.

17. Ochoa J, Danta G, Fowler TJ, Gilliatt RW. Nature of the nerve lesion caused bya pneumatic tourniquet. Nature. 1971;233:265-6.

18. Ochoa J, Fowler TJ, Gilliatt RW. Anatomical changes in peripheral nervescompressed by a pneumatic tourniquet. J Anat. 1972;113 (pt 3):433-55.

19. Gilliatt RW, Ochoa J, Rudge P, Neary D. The cause of nerve damage in acutecompression. Trans Am Neurol Assoc. 1974;99:71-4.

20. McLaren AC, Rorabeck CH. The pressure distribution under tourniquets.J Bone Joint Surg Am. 1985;67:433-8.

21. Shaw JA, Murray DG. The relationship between tourniquet pressure andunderlying soft-tissue pressure in the thigh. J Bone Joint Surg Am.1982;64:1148-52.

22. Graham B, Breault MJ, McEwen JA, McGraw RW. Perineural pressures underthe pneumatic tourniquet in the upper extremity. J Hand Surg Br. 1992;17:262-6.

23. Graham B, Breault MJ, McEwen JA, McGraw RW. Occlusion of arterial flow inthe extremities at subsystolic pressures through the use of wide tourniquet cuffs.Clin Orthop Relat Res. 1993;286:257-61.

24. Pedowitz RA, Gershuni DH, Botte MJ, Kuiper S, Rydevik BL, Hargens AR. Theuse of lower tourniquet inflation pressures in extremity surgery facilitated by curvedand wide tourniquets and an integrated cuff inflation system. Clin Orthop Relat Res.1993;287:237-44.

25. McEwen JA, Inkpen K, Younger A. Thigh tourniquet safety. Surg Technol.2002;24:8-18.

26. Younger AS, McEwen JA, Inkpen K. Wide contoured thigh cuffs and automatedlimb occlusion measurement allow lower tourniquet pressures. Clin Orthop RelatRes. 2004;428:286-93.

27. McEwen JA, Kelly DL, Jardanowski T, Inkpen K. Tourniquet safety in lower legapplications. Orthop Nurs. 2002;21:55-62.

28. Tuncali B, Karci A, Tuncali BE, Mavioglu O, Ozkan M, Bacakoglu AK, Baydur H,Ekin A, Elar Z. A new method for estimating arterial occlusion pressure in optimizingpneumatic tourniquet inflation pressure. Anesth Analg. 2006;102:1752-7.

29. Reilly CW, McEwen JA, Leveille L, Perdios A, Mulpuri K. Minimizing tourni-quet pressure in pediatric anterior cruciate ligament reconstructive surgery:a blinded, prospective randomized controlled trial. J Pediatr Orthop. 2009;29:275-80.

30. AORN, recommended practices for use of the pneumatic tourniquet. In: Peri-operative standards and recommended practices. 2009 ed. Denver, CO: AORN Inc;2009. p 373-85.

31. Majno G. The healing hand: man and wound in the ancient world. Cambridge,MA: Harvard University Press; 1975. p 278-9, 403-5.

32. Kragh JF Jr, Walters TJ, Baer DG, Fox CJ, Wade CE, Salinas J, Holcomb JB.Survival with emergency tourniquet use to stop bleeding in major limb trauma. AnnSurg. 2009;249:1-7.

33. Kragh JF Jr, Walters TJ, Baer DG, Fox CJ, Wade CE, Salinas J, Holcomb JB.Practical use of emergency tourniquets to stop bleeding in major limb trauma.J Trauma. 2008;64(2 Suppl):S38-50.

34. NAEMT. PHTLS prehospital trauma life support: military version. 6th ed. St.Louis: Mosby; 2006. p 501-19.

35. Hodgetts TJ, Mahoney PF. The military tourniquet: a response. J R Army MedCorps. 2007;153:12-5.

36. Boiko M, Roffman M. Evaluation of a novel tourniquet device for bloodlesssurgery of the hand. J Hand Surg Br. 2004;29:185-7.

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37. Orbay H, Unlu RE, Kerem M, Sensoz O. Clinical experiences with a new tour-niquet device. Ann Plast Surg. 2006;56:618-21.

38. Colville J, Small JO. Exsanguination of the upper limb in hand surgery com-parison of four methods. J Hand Surg Br. 1986;11:469-70.

39. Klenerman L. The tourniquet manual: principles and practice. London:Springer; 2003.

40. Olivecrona C, Tidermark J, Hamberg P, Ponzer S, Cederfjall C. Skin protectionunderneath the pneumatic tourniquet during total knee arthroplasty: a randomizedcontrolled trial of 92 patients. Acta Orthop. 2006;77:519-23.

41. Tredwell SJ, Wilmink M, Inkpen K, McEwen JA. Pediatric tourniquets: analysisof cuff and limb interface, current practice, and guidelines for use. J Pediatr Orthop.2001;21:671-6.

42. McEwen JA, Inkpen K. Tourniquet safety: preventing skin injuries. Surg Tech-nol. 2002;24:6-15.

43. Flatt AE. Tourniquet time in hand surgery. Arch Surg. 1972;104:190-2.

44. Klenerman L. Tourniquet time—how long? Hand. 1980;12:231-4.

45. Bruner JM. Time, pressure, and temperature factors in the safe use of thetourniquet. Hand. 1970;2:39-42.

46. Ostman B, Michaelsson K, Rahme H, Hillered L. Tourniquet-induced ischemiaand reperfusion in human skeletal muscle. Clin Orthop Relat Res. 2004;418:260-5.

47. Wilgis EF. Observations on the effects of tourniquet ischemia. J Bone JointSurg Am. 1971;53:1343-6.

48. Klenerman L, Biswas M, Hulands GH, Rhodes AM. Systemic and local effectsof the application of a tourniquet. J Bone Joint Surg Br. 1980;62:385-8.

49. Parmet JL, Berman AT, Horrow JC, Harding S, Rosenberg H. Thromboembolismcoincident with tourniquet deflation during total knee arthroplasty. Lancet.1993;341:1057-8.

50. Jarrett PM, Ritchie IK, Albadran L, Glen SK, Bridges AB, Ely M. Do thigh tour-niquets contribute to the formation of intra-operative venous emboli? Acta OrthopBelg. 2004;70:253-9.

51. Christodoulou AG, Ploumis AL, Terzidis IP, Chantzidis P, Metsovitis SR,Nikiforos DG. The role of timing of tourniquet release and cementing on perioper-ative blood loss in total knee replacement. Knee. 2004;11:313-7.

52. Rama KR, Apsingi S, Poovali S, Jetti A. Timing of tourniquet release in kneearthroplasty. Meta-analysis of randomized, controlled trials. J Bone Joint Surg Am.2007;89:699-705.

53. McEwen JA, McGraw RW. An adaptive tourniquet for improved safety in sur-gery. IEEE Trans Biomed Eng. 1982;29:122-8.

54. Ishii Y, Noguchi H, Matsuda Y, Takeda M, Higashihara T. A new tourniquetsystem that determines pressures in synchrony with systolic blood pressure. ArchOrthop Trauma Surg. 2008;128:297-300.

55. Kuwabara S. Carpal tunnel syndrome: demyelinative or ischemic conductionblock? Clin Neurophysiol. 2009;120:223-4.

56. Ikemoto T, Tani T, Taniguchi S, Ikeuchi M, Kimura J. Effects of experimentalfocal compression on excitability of human median motor axons. Clin Neurophysiol.2009;120:342-7.

57. UnitedStatesDefenseAdvancedResearchProjectsAgency (DARPA).DeepBleederAcoustic Coagulation (DBAC). http://www.darpa.mil/STO/smallunitops/dbac.html.

58. Science and Society Picture Library. http://www.sciencemuseum.org.uk/hommedia.ashx?id=9066&size=Large

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2/19/2014 Tourniquet Use And Care

http://www.tourniquets.org/use_care.php 7/13

past the tourniquet cuff, the surgeon may request

that tourniquet pressure be increased. One

commonly used method is to increase pressure in

25 mmHg increments until blood f low stops.

Figure 12.Cuff with limbprotection sleeve folded backover distal edge

Intraoperative Monitoring

Intraoperative monitoring of tourniquet safety parameters reduces the risk ofcomplications. During the procedure, it is important to monitor the patient's bloodpressure, tourniquet pressure, and tourniquet time.

Blood Pressure

Monitor the patient's blood pressure for fluctuations and relate this information to thesurgeon.

Tourniquet Pressure

Adjust the tourniquet pressure at the physician's request. Monitor the cuff pressuredisplay during surgery and immediately report any changes to the surgeon. Anysudden loss of cuff pressure intraoperatively is a cause for serious concern. If thetourniquet cuff fails for any reason, deflate it fully, and re - exsanguinate the limb beforere - inflation. Re - inflation over blood - filled vasculature may lead to intravascularthrombosis.

Tourniquet Time

It is the physician's responsibility to determine when the tourniquet is to be inflated, atwhat pressure, for how long, and at what point in the procedure the tourniquet shouldbe released. It is customary to prominently note the time of cuff inflation and to notifythe physician after a certain time has elapsed and at pre - established intervalsthereafter. Modern electronic tourniquet systems have an elapsed time display and analarm which can be set to sound after a predetermined amount of tourniquet inflationtime.

There is no clearcut rule as to how long a tourniquet may be inflated safely, althoughvarious investigators have addressed effects of ischemia on muscle and nerve to definea relatively "safe" period of tourniquet hemostasis. In practice, safe tourniquet inflationtime depends greatly on the patient's anatomy, age, physical status, and the vascularsupply to the extremity. Unless instructed otherwise, report to the surgeon when 60minutes of tourniquet time has elapsed. There is general agreement that for reasonablyhealthy adults, 90 minutes should not be exceeded without releasing the tourniquet fora short time.

Releasing the tourniquet allows for removal of metabolic waste products from the limband nourishment of the tissue with oxygenated blood. During this time, elevate thelimb 60 degrees to encourage venous return and apply steady pressure to the incisionwith a sterile dressing. Tissue aeration periods should last at least 10 and preferably15 minutes the first time and 15 - 20 minutes subsequently. To proceed with thesurgery, re - exsanguinate the limb before reinflating the cuff. Take care during thisprocedure to maintain the sterility of the operative field. No known safe limit to thenumber of aeration intervals during prolonged tourniquet time has been established.

Deflating the Tourniquet

At the surgeon’s request, deflate the tourniquet cuff by taking the following steps:

1. Apply pressure dressings over the incision to protect the w ound from blood resurgence.

Ideally, the f inal bandage is applied and pressure is exerted over the incision prior to tourniquet

cuff deflation, to prevent blood resurgence. Sometimes, how ever, the tourniquet is deflated

before incisional closure in order to better identify and control bleeding.

2. If necessary to prevent blood resurgence, elevate the limb 45 - 60 degrees. Transient pain

upon tourniquet release can also be lessened by elevating the limb.

3. Deflate the tourniquet cuff rapidly to establish immediate venous return and prevent

engorgement.

4. Record the time of deflation.

5. Immediately remove the deflated cuff and any underlying limb protection follow ing cuff

RP: Pneumatic Tourniquet though the application time was relatively short (ie, 45 minutes), alarms are necessary to "varn about conditions that moy cause pa ti en t harm. l!H..J..f!J

Recommendation V

Tourniquet inflation time and patient condition should be monI­tored while the tourniquet cuff is inflated.

Tourniquet inflat ion time has a d irect correlation to tourn iquet-related complications (ie, increased infla­tion time increases the risk for injury), Tho puticnl's systemic response to ischemia is dependen t on both tissue type and tourniquet t ime, ;:.u While cardiac mus­cle has a higher demand for oxygen, skeleta l muscle is considered highly susceptible to ischemia . .llJ.li...l..IJ This is because of th e higher volumes of skeletal muscle mass releasing toxic substances in to Lb o circulatory system ,·"hen reperfusion occurs, which can then lead to a severe inflammatory response .li!Z·lllll Excessive tOlll'lli ­quet inflation time (ie , two to three hOUTS) may res ult in metabo lic changes: muscle damage; impaired pul­monary. hepatic, or renal function; neurological com­plications; or pain.llliI:.U.J

To determine tbe efficacy a n d safe ty of d is ta ll y placed pneumatic tourniquets, researchers inilialed a retrospective study to review 3,027 procedures during which the surgeons used ankle tourniquets. Following a chart rcvie",." the research ers determined th;:11 the duration of ankle ischemia V,laS as short as rour min­utes to as long as 139 minutes. Tourniquet failure was reported in 50 cases. Clinically, five compli cat ions were determined (ie, three post- tourniquet syndrome, one sickle cell-related problem. ono DVT) and all even­lually resolved. Based on the stu dy, tbe authors con­cluded that an upper limit of two hours resulted in fewer complications.a

[n a prospective study of awake patients, researc h­ers inves tigD tod tolerance of intraopera tive tourni quet pain. The study \'\'as designed to include 1,000 patients undergoing elective foot surgery with a local block, but 12 patients were excluded becau se the surgeon chose not to use a tourniquel. This left a sample size of 988 patients . The researchers foun d that 31 patien ts (3. 1%) expressed pain during the procedure and eighl or those experie nced symptoms (eg, breakthroug h b lee d ing from reduced tourniquet pressure, oversedation, exces­sive restlessness) that requ ired the surgeon to interru pt the procedure. Of those eight pat ients, the anes th esia professional converted four patients to general anes­thesia. The maximum tourniquet inflation time was 90 minutes (ie, range two to 90 minules, median 18 min­utes) . The researchers con clud ed tha t for foo t p roce­dures with local blocks and ankle tourniquets, a tour­niquet time of up to 30 minutes is tolerated by piltients younger than 70 years of age, but 1 % of the patients will report pain for each 11 m inu tes beyond 30 min­utes . They recommen ded cauti on when ad ministering local anesthesia to patients o lder than 70 years, espe­cially if the tourniquet inflation time is expecteci to be longer than 30 minutes.M

e36

In a retro spec tive review of more than 1,000 patients w ho had total knee arthroplas ties (ie, primary and revision knee replacements). researchers set out to identify risk factors that contribute to neurological complications. All patients had tourniquet times grea ter than 120 minutes. The researchers reported that 90 pa tients (7.7 0/0 ) experienced 129 peron ea l andlor tibial nerve palsies. They concluded that extended tourniquet times. the patient's age (ie, postoperative neurological dysfunction was associated with younger ago ), and the presence of preoperative flexion conLrac­tures were contributing factors to neurological compli­cations. The authors also reported U1at total tourniquet time and a reperfusion interval only modestly decreased the risk of nerve inju ries. ill

Twen ty-six patients undergoing arthroscopic ante­rior c ruciate ligament repairs participated in a prospec­ti ve open randomized study that compared metabolic effects of usi ng wide, curved tourniquet cuffs at a pres­sure of 250 mm Hg in one group and narrow, straight culTs at a pressure of 350 mm Hg in tbe oth er. The researchers reported a significant correlation between femoral vein lactate levels and tourniquet time. They founel the test parameters for measuring muscle inju­ries an d anacrobic metabolism wore the same bcl\·veen the two groups ro[' the first hour of tourniquet inflation. but the metaboli c changes increased as the tourniqu et time increased. ill

V.a. Pneumali c tourniquet inflat ion lime shou ld be kep t to a minimum. {Likely to be Effective]

Even with relatively short tourniquet infla­tion times (ie, 26 minutes ± eight minutes), researc hers have fou nd s ignificant markers of systemic inflam matory r es p onse w hen they were measured 15 minutes after tourniqu e t deflati on.w Inflation times of 60 minutes for an upper extremity and 90 minutes for a lower extremity have been iden tified as a general guideline for in flation dura ti on.li. However, some sources indica te that two hours is a safe time limit for tourniquet inflation.~ In pediat­ric patie nts, inflation times of less than 75 min­ut es for lower extremit i es h as been recommended.ill

Irr eversi ble ske letal muscle damage is thought to begin after tb ree hours of isch emia and is extensive at six hours. ill Allowing inter­mittent repcrfusion restores oxygenation and releases toxins.J1 Deflating the tourniquet every two hours with at leas t a 10-minute reperfus ion time has been identified as a strategy to con­sider to decrease the r isk for tissue damage. 1./! Another approach is to release the tourniquet after 90 minutes for at least 10 to 15 minutes for the first reperfusion period . then 15 to 20 min­utes for each subsequent repe rfusion period. l1

However, it has al so been reported that imple­menting reperfusion periods after 60 to 90 min­ut es of ischemia can con tribute to muscle injury. z.J

LcerSE'd 1(1 t.'.lc'Jae: jaTieson ANSI order X.32402;). DO'lmlc'du(>d 6/1 712C 136·I:i:.lM Single U~E li·::('nse ':Jrlv Cor"'Jrg 2nd 1o?!\·.'ork ng prO'1il;ite'J

rabbits with damage to skeletal muscle after reperfusion for one hour, followingfour hours of ischaemia with pneumatic tourniquets on a hind limb.10 There was aconsiderable amount of ultrastructural damage to the anterior tibial muscles accom-panied by a rise in circulating creatine kinase activity.

Pretreatment of animals with depot methylprednisolone by a single 8-mg intra-muscular injection led to preservation of the structure of tibialis anterior on bothlight and electron microscopy. High-dose, continuous intravenous infusion withascorbic acid (80 mg/h) throughout the period of ischaemia and reperfusion alsopreserved the structure of the muscle. Allopurinol in various doses had no effect.

These findings are fully compatible with a mechanism of ischaemia–reperfusion-induced injury, involving generation of oxygen radicals and neutrophil sequestrationand activation. The findings indicate that damage to human skeletal muscle caused by prolonged use of a tourniquet is likely to be reduced by simple pharmacologicalintervention.

3.3.2 Physical Modification

The practice of using breathing periods represents an attempt to reduce ischaemicinjury. This involves releasing the tourniquet after a set period of ischaemia to allowreperfusion, with the aim of returning tissue to its pre-ischaemic state, before subject-ing the limb to a further period of ischaemia. Several studies have defined the appro-priate breathing periods for the time ischaemia is required.

Newman, on the basis of studies in rats with nuclear magnetic resonance (NMR) spec-troscopy, suggested that the biochemical determinant of the speed of recovery afterthe release of the tourniquet was the level of ATP.10 Rapid recovery always occurredin the presence of ATP but not in its absence. He found that hourly ten-minutebreather periods prevented the depletion of ATP, and hence during three hours ofischaemia the metabolic demands for chemical energy were met. If the interval wasonly five minutes, this did not prevent ATP depletion and in addition to causing adeterioration of tissue pH did not shorten the recovery time. Pedowitz, using tech-netium uptake, found in a rabbit model that with a tourniquet time of four hours,skeletal muscle injury beneath the cuff was reduced significantly by hourly ten-minute reperfusion intervals.11 He noted that a ten-minute reperfusion period after atwo-hour tourniquet tended to exacerbate muscle injury. Reperfusion intervals couldprolong the duration of anaesthesia, increase blood loss, or produce haemorrhagicstaining and oedema.12 Nevertheless, Sapega and colleagues recommended on thebasis of studies on dogs that ischaemic injury to muscle can be minimised by limit-ing the initial period of tourniquet time to 1.5 hours.13 Release of the tourniquet forfive minutes permitted a further period of 1.5 hours. With knowledge of theischaemia–reperfusion syndrome, the use of breathing periods is not logical, as reper-fusion is now recognised as a major cause of damage to limbs after ischaemia. Furtherdamage by free-radical-mediated mechanisms is likely even after the biochemistry of the venous blood returns to normal equilibrium. Work in animals has suggested thatallowing reperfusion may actually increase the amount of damage to the ischaemiclimb in certain structures.14

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The Tourniquet Manual ➀➁➌➃➄➅➆