Tourniquet pain in a volunteer study: effect of changes in cuff width and pressure

This study examines the relationship between pneumatic tourniquet cuff size, occlusion pressure and the resulting pain. Two tourniquet cuff widths were used, a wide (14 cm) and a narrow cuff (7 cm). Twenty volunteers were divided into two groups for tourniquet application: a pressure group in which the tourniquet was inflated to a pressure equal to the systolic pressure + 100 mmHg, and a saturation group in which the tourniquet was inflated to 10 mmHg above the loss of arterial pulse, as indicated by cessation of pulse waveform on an oximeter. According to a randomised cross-over protocol, subjects were studied using wide and narrow cuffs simultaneously and/or successively on both arms. Pain was assessed by subjects by means of a visual analogue score (0-10 cm). Occlusion pressures were similar for all volunteers in the pressure group and significantly higher than those in the saturation group with both the wide and narrow tourniquets. The wide cuff data turned out to be significantly lower than the narrow cuff results. Subjects in the pressure group could tolerate pain with the narrow cuff for significantly longer than with the wide cuff. However, in the saturation group, volunteers tolerated the wide cuff for longer. Pain intensity increased more rapidly in those in the pressure group with the wide cuff than with the narrow cuff. In contrast, volunteers in the saturation group found the narrow cuff to be more painful than the wide cuff. In conclusion, this study has shown that a wide tourniquet cuff is less painful than a narrow cuff if inflated at lower pressures and at these lower pressures it is still effective at occluding blood flow.     

牛磺酸在大鼠止血带休克后肺损伤中的保护作用

目的 :观察牛磺酸对大鼠止血带休克 (ToS)后肺损伤的保护作用 .方法 :采用大鼠止血带休克模型 ,将Wistar大鼠随机分为 3组 :对照组 (control)、止血带休克组 (ToS)、牛磺酸 +止血带休克组 (Tau +ToS) ,分别测定动脉血氧分压 (PaO2 )和二氧化碳分压 (PaCO2 ) ,肺系数 (LI)和肺通透指数 (LPI)以及肺组织黄嘌呤氧化酶 (XOD)、超氧化物歧化酶 (SOD)、谷胱甘肽过氧化物酶 (GSH PX)、过氧化氢酶 (CAT)及活性氧 (ROS)、组织Ca2 + 含量、丙二醛 (MDA)和髓过氧化物酶 (MPO)的含量 .结果 :po牛磺酸可有效地改善肺呼吸功能 [PaO2 (1 1 .7± 1 .6 )kPavs (8.5± 0 .7)kPa ,P <0 .0 1 ],降低自由基生成酶的活性[XOD (6 7± 7) μkat/gvs (79± 1 3) μkat/g;(76± 1 1 ) μkat/gvs(1 0 9± 2 6 ) μkat/g ,P <0 .0 5或 P <0 .0 1 ],增加自由基清除酶的活性 [SOD (4 8± 8) μkat/gvs (2 0± 3) μkat/g;CAT (38± 8)vs (1 9± 6 ) μkat/g ;GSH PX (86± 2 ) μkat/gvs (2 3± 4 ) μkat/g,P <0 .0 1 ],抑制组织脂质过氧化的发生 [MDA (1 0 8± 1 7)μmol/gvs (1 4 7± 2 3) μmol/g ,P <0 .0 5 ;(1 32± 1 3) μmol/gvs(1 5 1± 1 9) μmol/g ,P <0 .0 5 ],减轻组织水肿及中性粒细胞的聚集 [MPO (0 .0 1 7± 0 .0 0     

Current concepts in tourniquet uses

Tourniquets have been around for many years, providing surgeons with a bloodless operative field and saving lives in the pre-hospital care of major limb trauma. However, their use does come with risk. It is therefore extremely important that we, as surgeons, fully understand the physiological influence they impose on patients, the complications associated with their use and, moreover, how to minimize the incidence of these complications. Most tourniquets are now electronically controlled pneumatic devices with built-in pressure sensors and timers. Classically, inflation to 250 mmHg in the upper limb and 300 mmHg in the lower limb is used, but a move towards patient-specific limb occlusion pressures is suggested, although it is more difficult due to the requirement of more time-consuming set-up. Complications from tourniquets can occur, such as nerve injury, pain, venous thromboembolism or even cardiac overload and reperfusion injury. Limiting use to key parts of an operation or using alternatives such as adrenaline infiltration and tranexamic acid can be of benefit. As such, any use of a tourniquet during an operation must be treated with caution and be deployed taking into account the specific characteristics of that particular patient.     

Sequestration of vecuronium bromide during extremity surgery involving use of a pneumatic tourniquet

Background: We hypothesized that sequestration of a neuromuscular blocking agent could occur during surgery involving use of an extremity tourniquet and cause changes in neuromuscular function after tourniquet release. Methods: Sixteen patients scheduled for total knee replacement were randomized to one of two groups. In Group 1,10 patients were administered O.lmg/kg of vecuronium 5 minutes prior to inflation of a pneumatic tourniquet; in Group II, 6 patients were administered O.lmg/kg of vecuronium after inflation of the tourniquet. The twitch (T₁) and train-of-four (TOF) were analyzed before and after release of the tourniquet, as was the rate of recovery of T₁ and TOF. Serial vecuronium plasma levels were drawn during the study. Results: The T₁ and TOF responses and the T₁ and TOF recovery rates were not significantly different between groups at tourniquet deflation. In Group I, after release of the tourniquet, Tj and TOF recovery rate decreased significantly over a 10-min period (10%±3 to 4%±4 and 0.12±0.06 to 0.06±0.04, mean±SD, respectively); in Group II, T₁ and TOF recovery rate increased significantly over a 10-min period following deflation of the tourniquet (10%±6 to 14%±7 and 0.10±0.03 to 0.18±0.02, respectively). Changes in pharmacodynamics were temporally associated with transient but statistically significant changes in vecuronium plasma levels. Overall pharmacokinetics during the study period were comparable between groups. After administration of neostigmine 30–40 μg/ kg i.v. all subjects in both groups showed complete TOF recovery within 15 min. Conclusions: Sequestration of a bolus dose of vecuronium, by a pneumatic tourniquet, causes transient changes in pharmacokinetics and pharmacodynamics. These changes are of limited clinical importance and do not affect reversibility of neuromuscular block.     

Performance of Junctional Tourniquets in Normal Human Volunteers

Abstract

Background. Inguinal bleeding is a common and preventable cause of death on the battlefield. Four FDA-cleared junctional tourniquets (Combat Ready Clamp [CRoC], Abdominal Aortic and Junctional Tourniquet [AAJT], Junctional Emergency Treatment Tool [JETT], and SAM Junctional Tourniquet [SJT]) were assessed in a laboratory on volunteers in order to describe differential performance of models. Objective. To examine safety and effectiveness of junctional tourniquets in order to inform the discussions of device selection for possible fielding to military units. Methods. The experiment measured safety and effectiveness parameters over timed, repeated applications. Lower extremity pulses were measured in 10 volunteers before and after junctional tourniquet application aimed at stopping the distal pulse assessed by Doppler auscultation. Safety was determined as the absence of adverse events during the time of application. Results. The CRoC, SJT, and JETT were most effective; their effectiveness did not differ (p > 0.05). All tourniquets were applied safely and successfully in at least one instance each, but pain varied by model. Subjects assessed the CRoC as most tolerable. The CRoC and SJT were the fastest to apply. Users ranked CRoC and SJT equally as performing best. Conclusion. The CRoC and SJT were the best-performing junctional tourniquets using this model.     

右美托咪定在老年2型糖尿病患者止血带下肢手术中的应用#br#

目的　探讨右美托咪定（DEX）对下肢手术2型糖尿病老年患者使用止血带后血清神经元特异性烯醇化酶（NSE）、氧化应激反应、炎症反应及术后认知功能的影响。方法　选择全麻止血带下行骨科下肢手术的老年2型糖尿病患者96例,采用随机数字表法分为DEX组和对照组,各48例。DEX组于全麻诱导后15 min内静脉泵注DEX 0.5 μg/kg,继之以0.5 μg/（kg·h）泵注直至手术结束前30 min,对照组给予相同容量生理盐水。分别于止血带充气前,放气后30 min、24 h和72 h采用硫代巴比妥酸法、双抗体夹心酶联免疫吸附试验（ELISA）法检测2组患者血清丙二醛（MDA）、NSE、肿瘤坏死因子（TNF）-α、白细胞介素（IL）-1β水平;采用简易精神状态评价量表（MMSE）法评定2组患者术前1 d,术后1 d、3 d认知功能;记录2组苏醒时间、拔管时间、不良反应情况。结果　与充气前比较,2组血清NSE水平从放气后24 h开始增加,而MDA、TNF-α、IL-1β水平从放气后30 min即开始增加（P＜0.05）;与对照组比较,DEX组血清NSE水平从放气后24 h开始降低,而MDA、TNF-α、IL-1β水平从30 min即开始降低（P＜0.05）;与术前 1 d比较,2组术后1 d、3 d的MMSE评分均降低（P＜0.05）;与对照组比较,DEX组MMSE评分在术后1 d、3 d升高（P＜0.05）。2组苏醒时间、拔管时间、不良反应发生率比较差异均无统计学意义。结论　DEX用于2型糖尿病老年患者止血带下肢手术可降低血清NSE,减轻氧化应激及炎症反应,改善术后认知功能。     

Tourniquet uses and precautions

Tourniquets have been around for many years providing surgeons with a bloodless operative field and saving many lives on the battlefield; however, their use does come with risk. It is therefore extremely important that we, as surgeons, fully understand the physiological influence they impose on patients, the complications associated with their use and moreover how to minimize the incidence of these complications.     

The 2009 Sydney shark attacks: case series and literature review

Background: There were 59 unprovoked shark attacks worldwide in 2008. Twelve of these occurred in Australia, ranking it as second only to the USA. In February 2009, two attacks occurred within 72 h in Sydney, Australia. Methods: The two patients involved survived severe limb trauma. Case 1 suffered bite trauma to the lower limb and hand and underwent staged debridement and early amputation. Case 2 presented with a hand severed at the level of the wrist that was initially replanted. However, it would succumb to progressive necrosis after 12 days. We discuss the aspects of these cases that contributed to the patients' survival and ultimately good functional outcomes. Discussion: New paradigms for the management of major trauma patients have emerged over the last decade. We consider recent advances in the understanding of pre‐hospital tourniquet use, rapid transit to the operating suite and damage control surgery, and examine how they impacted on the management of our patients. Very little is known about the microbiology of shark bites. Organisms from sea water, the patient's skin and the shark's mouth must all be considered when selecting appropriate antimicrobial prophylaxis. The planning of definitive surgery in severe limb trauma is dependent on the interactions of a number of factors including physical, psychological and social issues. The decision to ultimately replant or amputate the effected limb is best made in union with the patient and their family.     

The arterial tourniquet: pathophysiological consequences and anaesthetic implications

The arterial tourniquet is widely used in upper and lower extremity surgery and in intravenous regional anaesthesia. The local and systemic physiological effects and the anaesthetic implications are reviewed. Localised complications result from either tissue compression beneath the cuff or tissue ischaemia distal to the tourniquet. Systemic effects are related to the inflation or deflation of the tourniquet. Safe working guidelines for the application of an arterial tourniquet have not been clearly defined.