Ultrastructural changes in rat peripheral nerve following pneumatic tourniquet compression

The sciatic nerves of 12 male rats were examined in the electron microscope 14 days after pneumatic tourniquet compression. Tourniquet pressure was maintained at 300 mmHg for varied lengths of time (30 minutes to 3 hours). Nerves compressed for 30 minutes showed very mild fissuring of the myelin without axonal degeneration. Examination of nerves compressed for 1 to 3 hours showed progressively more varied and extensive damage. Changes included splaying of myelin lamellae, axonal shrinkage with periaxonal edema. Schwann cell hypertrophy, and an increase in the number of microtubules and mitochondria per unit area. The myelin sheaths of some fibers, compressed for more than 2 hours, were completely ruptured. These changes resemble nerve lesions which could be induced by a variety of experimental procedures. Ultrastructural changes produced by tourniquet compression are apparently time-related and affect large-diameter nerves more profoundly than smaller-diameter nerves. The data reported provide an explanation for delayed muscle rehabilitation experienced by patients who have undergone extremity surgery with pneumatic tourniquet application. The evidence presented suggests that the incidence of tourniquet palsy may be far greater than previously recognized.     

Fibrinolysis after application of a pneumatic tourniquet

The fibrinolytic system was studied after application of a pneumatic tourniquet in 22 patients undergoing elective orthopaedic surgery and during 20-min venous occlusion in 17 healthy subjects. Blood was sampled before anaesthesia (A), before operation (B) and after operation from the ipsilateral (C) and the contralateral (D) limb. Tissue plasminogen activator (t-PA) activity, t-PA antigen and t-PA activity/t-PA antigen ratio increased by, respectively, 557, 109 and 168% in the C samples as compared with A blood (all differences statistically significant). The t-PA activity and t-PA antigen increased slightly in the systemic circulation (B and D) but were significantly less in C than after venous occlusion. Fast-acting inhibitor of t-PA increased significantly in C (15%). During compression with a pneumatic tourniquet, mainly local fibrinolytic activation occurs, and this activation partly explains the low incidence of postoperative deep venous thrombosis after use of a tourniquet.     

A new technique for hemodialysis access surgery: Use of the pneumatic tourniquet

The purpose of this study was to determine whether tourniquet occlusion could be safely used on the upper extremity for vascular control during hemodialysis access surgery. The hospital and outpatient records of 44 patients undergoing 105 hemodialysis access procedures were retrospectively reviewed. In 48 procedures tourniquet occlusion was used for vascular control, whereas in 57 procedures vascular clamps were used. In those procedures in which the tourniquet was used; the mean tourniquet time was 30 minutes and the mean tourniquet pressure was 242 mm Hg. The operative time was significantly less in the tourniquet group as compared to the clamp group (72.5 minutes vs. 84 minutes, respectively;p=0.029). There was no statistically significant difference in the incidence of nerve injury, bleeding, hematoma, vascular steal, infection, or swelling between the two groups. There were no complications related specifically to the use of the tourniquet. There was no difference in primary patency in comparing the tourniquet control group with the clamp control group (p>0.5). The use of a pneumatic tourniquet for vascular control during hemodialysis access surgery allows for a faster, technically easier operation with no increase in the complication rate and no effect on primary patency.Presented at the Fifth Annual Winter Meeting of the Peripheral Vascular Surgical Society, Breckenridge, Colo., January 27–29, 1995.     

Silicone ring tourniquet versus pneumatic cuff tourniquet in carpal tunnel release: a randomized comparative study

Background

The aim of the present study was to compare the pain levels resulting from the use of a silicone ring tourniquet (SRT) to those resulting from the use of a classic pneumatic cuff tourniquet (PT) in patients undergoing carpal tunnel release under local anesthesia.

Materials and methods

Fifty patients that underwent carpal tunnel release under local anesthesia were randomized using the technique of stratified randomization by minimization. A forearm tourniquet was applied: a standard PT was used in 25 patients, and an SRT was used in the other 25 patients (the model of SRT used was selected according to the standard systolic blood pressure). Patient demographics and complications were recorded. Pain levels were assessed with the visual analogue scale and were recorded (a) just after tourniquet application, (b) 5 min after tourniquet application, and (c) just before tourniquet removal.

Results

There was no statistical significant difference in patient demographics between the two groups. The mean tourniquet time was similar for both groups (p = 1.000). The difference between the mean final pain level and the mean initial pain level was statistically significant for the SRT group (p = 0.010) and highly statistically significant for the PT group (p < 0.001). The mean final pain level for the PT group was higher than that for the SRT group (p = 0.043).

Conclusions

According to the findings of this study, in patients who underwent carpal tunnel release under local anesthesia, the pain levels at the end of the operation and those just before the removal of the tourniquet were higher in the PT group than in the SRT group of patients.     

The pneumatic tourniquet in arthroscopic surgery of the knee

In a randomized study 56 patients undergoing arthroscopic surgery of the knee were randomly allocated to one of 2 groups: surgery with a tourniquet and surgery without a tourniquet. No significant difference was found between the 2 groups with regard to operating times, technical intraoperative difficulties, identification of intraarticular structures, postoperative pain or postoperative complications. In neither group was the procedure abandoned due to technical difficulties. The pain scores in the non-tourniquet group were lower than those in the group of patients operated on with the use of a pneumatic tourniquet. The study suggests that the use of a tourniquet in arthroscopic surgery of the knee is unnecessary.     

The use of pneumatic tourniquet in total knee arthroplasty: a meta-analysis

Background

Pneumatic tourniquet use in total knee arthroplasty (TKA) is always a controversial issue. The aim of the present study is to assess the effectiveness and safety of its use in patients receiving primary unilateral TKA, and to explore the most safe and effective protocols.

Materials and methods

This review was based on cochrane methodology for conducting meta-analysis. Only randomized controlled trials (RCTs) were eligible for this study. The participants were adults who had undergone primary unilateral TKA. The Review Manager Database (RevMan version 5.0, The Cochrane Collaboration 2008) was used to analyze the dates of the selected studies.

Results

Thirteen RCTs involving 859 patients were included in this analysis. The use of tourniquet could significantly reduce operation time (mean difference ?5.01 min, P = 0.003), intraoperative blood loss (mean difference ?201.85 ml, P < 0.00001) and total blood loss volumes (mean difference ?125.03 ml, P = 0.61). But postoperative (mean difference 45.99 ml, P = 0.68) were slightly increased in that situation. With respect to surgical complications, a tendency of increasing risk ratio was observed for tourniquet group.

Conclusions

Our results indicate that tourniquet application could reduce surgical time, intraoperative blood loss and total blood loss, but increases postoperative total blood loss. With respect to postoperative complications, DVT and surgical site infection rates are relatively augmented in the tourniquet group.     

气压止血带在膝关节置换术中应用的研究进展

气压止血带通过充气加压袖带压迫肢体近端动脉以达到手术区域止血的效果.膝关节置换术中使用气压止血带可以获得优质的手术视野、无血的操作区域以及良好的假体置入环境.但随着现代医学的不断发展,气压止血带使用所带来的各种并发症不断被挖掘与重视.如何更加精确地使用气压止血带,发挥其优势并规避风险,已成为气压止血带研究的主要方向.该...     

充气式止血带在全膝关节置换术中的应用研究

全膝关节置换术中使用充气式止血带能提供良好术野及骨水泥-骨结合界面.然而,使用止血带会增加术中、术后发生致命性血栓栓塞的风险,引起肌肉缺血-再灌注损伤而加重术后早期疼痛,并增加皮肤水疱形成及血管神经损伤的风险,不利于术后早期功能康复锻炼,还会影响术中对髌骨轨迹的判断,对降低术中、术后总失血量的作用也不明显.如何正确使用止血带仍值得探讨,止血带对全膝关节置换术的影响仍需深入研究.     

安装大腿近侧气囊止血带对髌股关节运动的影响

目的探讨膝关节屈曲和伸直状态下安装大腿近侧气囊止血带对髌股关节运动的影响。方法收集住院的非髌股关节疾病患者,选择膝关节20侧,在腰麻或连续硬膜外状态下屈膝30°时测量膝关节髌骨高度和股骨滑车角,然后分伸膝位安装止血带和屈膝位安装止血带两组自身先后对比,测量膝关节不同屈曲角度下Laurin髌股关节外侧角和Merchant吻合角。比较气囊止血带在膝关节不同屈伸状态下对髌股关节运动学的影响。结果在膝关节屈曲30°时,髌骨高度的Caton指数为(1.02±0.19),股骨滑车角(138.9±7.4)°。在膝关节屈曲过程中,髌股关节呈现Merchant吻合角增大的趋势,尤其在膝关节屈曲30~45°的时候变化明显,当屈曲角度继续增大时吻合角基本稳定;Lauren髌股关节外侧角保持相对稳定。伸直位和屈曲位安装止血带引起髌股关节Merchant吻合角和Lauren髌股关节外侧角间的差异没有统计学意义。结论在正常膝关节,大腿近侧气囊止血带对髌股轨迹的影响主要表现为最初屈曲的45°内Merchant髌股吻合角的的增大,而Laurin髌股关节外侧较保持相对稳定。伸直位和屈曲位安装大腿近侧气囊止血带对正常膝关节髌股关节运动的改变没有统计学意义。     

充气止血带在膝关节置换术中的应用观察

目的探讨膝关节置换术中充气止血带的使用方法。方法回顾性研究我院自2005年1月至2008年12月,326例在我院行初次单侧膝关节置换手术患者的临床资料,根据术中止血带不同的使用方法,分为三组,A组126例,在假体安装完毕、骨水泥固化后放松止血带,术野充分止血后关闭切口;B组142例,在关闭切口,加压包扎后放松止血带;C组58例,未使用止血带。观察三组患者术中和术后失血、总失血量以及术后深静脉栓塞(DVT)并发症发生率。结果A组患者术中失血(242±120)ml和术后失血(214±156)ml,总失血量(467±232)ml,DVT发生率12.7%;B组患者术中失血(224±116)ml和术后失血(387±160)ml,总失血量(610±252)ml,DVT发生率26.8%;C组患者术中失血(463±246)ml和术后失血(184±112)ml,总失血量(654±303)ml,DVT发生率12.1%。结论膝关节置换术中使用充气止血带,在假体安装完毕、骨水泥固化后再放松止血带止血的方法能够减少围手术期失血,而且不增加DVT的发生率,是一种较好的止血带使用方法,对提高临床护理质量有重要意义。     

气压止血带在四肢骨科手术中应用研究进展

随着新型骨科手术辅助工具气压止血带在四肢骨科手术中的广泛应用,其并发症越来越引起临床重视.目前对气压止血带在四肢骨科手术中的操作细节,尤其是充气压的选择存在许多争议.为充分发挥气压止血带的作用,需要在使用范围、使用时间及设定充气压方面有一规范认识,及时防止可能引发的副损伤,避免并发症发生.该文就气压止血带在四肢骨科手术...     

骨科四肢手术气压止血带安全使用的最佳证据应用

目的将气压止血带安全使用的最佳证据应用于骨科四肢手术患者,降低气压止血带使用并发症的发生率。方法遵循JBI的最佳证据临床应用程序,使用证据的持续质量改进模式图,获取气压止血带压力安全使用的相关证据,制定10条审查标准。采用现场观察、问卷调查、专家访谈等方法收集证据应用的障碍,分析可获得的资源,制定解决办法。结果证据应用后10条审查指标的执行情况显著高于基线审查(均P0.01);手术后即刻皮肤损伤发生率由基线审查的65.0%降至20.0%(P0.01)。结论手术室气压止血带安全使用最佳证据的临床应用,可规范手术室护士气压止血带临床操作,减少使用后并发症的发生,保证骨科手术患者的安全。     

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.     

The effects of a pneumatic tourniquet on blood loss in total knee arthroplasty.

OBJECTIVE: In lower-extremity surgery there are significant risks associated with the use of tourniquets. This prospective study was done to assess to what extent these risks may be offset by the potential advantages of tourniquets, namely reductions in blood loss, length of hospital stay and complication rates. DESIGN: A prospective case study. SETTING: A major urban hospital. PATIENTS: Sixty-three consecutive patients scheduled for primary cemented total knee arthroplasty (TKA) were blindly randomized into tourniqet (n = 33) and non-tourniquet (n = 30) groups. INTERVENTION: TKA during which a pneumatic tourniquet was applied or not applied to control blood loss. MAIN OUTCOME MEASURES: Perioperative blood loss, operating time, complication rates, hospital stay and transfusion needs. RESULTS: Differences in the total measured blood loss, intraoperative blood loss and the Hemovac drainage blood loss between the 2 groups were not significantly different (p > 0.25). The calculated total blood loss was actually lower in the non-tourniquet group (p = 0.02). Between the groups there were no statistical differences in surgical time, length of hospital stay, transfusion requirements or rate of complications (although there was a trend to more complications in the tourniquet group (p = 0.06)). CONCLUSION: The effectiveness of a pneumatic tourniquet to control blood loss in TKA is questionable.     

Use of a tourniquet in patients with sickle-cell disease

Fifteen patients, 13 male and two female, known to be carrying the sickle-cell gene (12 HbSS and 3 HbAS), who were undergoing operations requiring a bloodless field, were included in the study. Of the 12 with HbSS, seven had haemoglobin A, component of between 11 and 27%, three had fetal haemoglobin ranging from 5.7 to 29% and the remaining two had increased haemoglobin A₂ concentrations suggesting a beta non-thalassaemia combination. All had a tourniquet applied to the appropriate limb and were given general anaesthesia with moderate hyperventilation throughout the procedure. The tourniquet inflation time was 61.7 ± 27.5 min. The mean PaO₂ remained above 200 mmHg, mean PaCO₂ was less than 37 mmHg, and pH ranged between 7.40 and 7.45. There were no clinically important changes in BP or ECG. All patients made uneventful recoveries and none developed sickle-cell crises. It is suggested that it is safe to use tourniquet in patients with sickle-cell disease provided optimum acid-base status and oxygenation are maintained throughout the procedure.     

Rational application of the pneumatic tourniquet in the knee joint endoprosthesis

Two different methods of the pneumatic tourniquet application were used while the knee joint prosthesis in two groups of patients: during the all operation and during the stage of implantation of artificial joint components. It is preferent to reduce the pneumatic tourniquet application duration to realize its positive qualities, to secure optimal adhesion of cement and costal bed and also to make less severe the consequences of intra- and postoperative period. The data obtained trust that the procedure, used by us, constitutes an optimal method of the pneumatic tourniquet application while the knee joint cement prosthesis.