The pneumatic tourniquet in arthroscopic surgery of the knee.
(25/227)
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. (+info)
Timing of the administration of tranexamic acid for maximum reduction in blood loss in arthroplasty of the knee.
(26/227)
We studied 99 patients who were undergoing total knee arthroplasty (TKA) to determine the optimum protocol for the administration of tranexamic acid (TNA) in order to reduce blood loss. It decreased by more than 40% after the administration of TNA. The haemostatic effect was greatest when TNA was given preoperatively and on deflation of the tourniquet. There was no increase in the incidence of adverse affects in the patients receiving TNA, compared with a control group. We conclude that two injections of TNA, one given preoperatively and one on deflation of the tourniquet, significantly reduce blood loss without increasing the risk of thromboembolic complications. (+info)
Human skeletal muscle energy metabolism during and after complete tourniquet ischemia.
(27/227)
The extent of cellular metabolic deterioration and its reversibility was studied on human skeletal muscle needle biopsies during operations in bloodless field. The tissue levels of high energy phosphates and glycolytic metabolites were analyzed after various times of tourniquet ischemia and compared to contralateral control extremity levels. In the ischemic extremity the phosphocreatine (CrP) levels decreased by 40% within 30-60 min and after 60-90 min a 60% reduction was found. No significant ATP changes occurred. Lactate levels increased by 225% after 30-60 min and by 300% after 60-90 min. The glucose and G-6-P levels increased slightly and indicated glycogenolysis. The rate of the metabolic changes decreased with ischemia time. In the control leg no significant metabolic changes could be seen. After the release of the tourniquet there was a rapid restoration of the phosphagen content and clearance of lactate in the ischemic leg. Near control levels of these substances were seen already after 5 min. The present results show that clinical tourniquet ischemia of up to 90 min duration produces less pronounced metabolic alterations than those seen in working muscle. (+info)
Controlled ischemia for complex venous surgery: the technique of choice.
(28/227)
Surgery under controlled ischemia has been extensively practiced by cardiac, plastic, orthopedic, vascular, and general surgeons. During the past 20 years, we have routinely used this technique to operate on a clean, bloodless field in complex cases of congenital vascular malformations. Based on our favorable experience, we have extended the use of the pneumatic tourniquet to complex cases of primary varicose veins. The use of the tourniquet has dramatically decreased the blood loss and operating time in complex venous surgery without complications secondary to its use. This technique represents a welcome alternative to the bloody, tedious, and time-consuming traditional varicose vein surgery of the past. Complex venous surgery for extensive varicose veins of the extremities can be safely and expeditiously performed under controlled ischemia. It should be the technique of choice. (+info)
Evaluation of the World Health Organization standard tourniquet test and a modified tourniquet test in the diagnosis of dengue infection in Viet Nam.
(29/227)
OBJECTIVES: A positive tourniquet test is one of several clinical parameters considered by the World Health Organization to be important in the diagnosis of dengue haemorrhagic fever, but no formal evaluation of the test has been undertaken. As many doctors remain unconvinced of its usefulness, this study was designed to assess the diagnostic utility of both the standard test and a commonly employed modified test. METHODS: A prospective evaluation of the standard sphygmomanometer cuff tourniquet test, compared with a simple elastic cuff tourniquet test, was carried out in 1136 children with suspected dengue infection admitted to a provincial paediatric hospital in southern Viet Nam. RESULTS: There was good agreement between independent observers for both techniques, but the sphygmomanometer method resulted in consistently greater numbers of petechiae. This standard method had a sensitivity of 41.6% for dengue infection, with a specificity of 94.4%, positive predictive value of 98.3% and negative predictive value of 17.3%. The test differentiated poorly between dengue haemorrhagic fever (45% positive) and dengue fever (38% positive). The simple elastic tourniquet was less sensitive than the sphygmomanometer cuff, but at a threshold of 10 petechiae (compared with the WHO recommendation of 20) per 2.5 cm2 the sensitivity for the elastic tourniquet rose to 45% (specificity 85%). Other evidence of bleeding was frequently present and the tourniquet test provided additional information to aid diagnosis in only 5% of cases. CONCLUSION: The conventional tourniquet test adds little to the diagnosis of dengue in hospitalized children. The simple, cheap elastic tourniquet may be useful in diagnosing dengue infection in busy rural health stations in dengue endemic areas of the tropics. A positive test should prompt close observation or early hospital referral, but a negative test does not exclude dengue infection. (+info)
The position of the tourniquet on the upper limb.
(30/227)
Our aim was to determine if a tourniquet placed on the forearm has any advantage in clinical practice over the usual position on the upper arm. We randomised 50 patients who were undergoing an open operation for carpal tunnel syndrome under local anaesthesia into two groups. One had a tourniquet on the upper arm and the other on the forearm. The blood pressure, pulse, and level of pain were recorded at intervals of five minutes during the operation. The surgeons were also asked to evaluate the quality of the anaesthesia, the bloodless field, and the site of the tourniquet. The patients tolerated the tourniquet on the upper arm and forearm equally well. The surgeons had some difficulties when it was placed on the forearm. We therefore recommend placement of a tourniquet on the upper arm for operations on the hand and wrist which are carried out under local anaesthesia. (+info)
Comparison of mepivacaine and lidocaine for intravenous regional anaesthesia: pharmacokinetic study and clinical correlation.
(31/227)
BACKGROUND: Limitations to the use of lidocaine for intravenous regional anaesthesia (IVRA) include lack of optimal intraoperative analgesia and systemic toxic reactions. This randomized double-blind study was conducted to compare intraoperative and postoperative analgesia, adverse effects, and plasma concentrations of mepivacaine or lidocaine, on release of the tourniquet in patients undergoing IVRA for distal upper limb surgery. METHODS: Forty-two adult patients were randomly allocated to receive either a 0.5% lidocaine solution 3 mg kg(-1) (n=20) or mepivacaine 5 mg kg(-1) (n=22). Plasma concentrations of both anaesthetic agents were measured at 5, 10, 20, 30, 45, and 60 min after deflation of the tourniquet by gas chromatography. RESULTS: Although plasma concentrations of mepivacaine and lidocaine were comparable 5 min after deflation, concentrations of lidocaine decreased significantly thereafter, whereas plasma concentrations of mepivacaine were similar over the 60-min study period. Supplementary analgesia during the intraoperative period was required by 45% of patients in the lidocaine group as compared with 9% in the mepivacaine group (P=0.02). No adverse effects were observed in patients given mepivacaine. In the lidocaine group, adverse effects were observed in 10% of the patients. The total ischaemia time, volume of the local anaesthetic, and duration of the surgical procedure were not significantly different between the two groups. CONCLUSIONS: Mepivacaine 5 mg kg(-1) ensured better intraoperative analgesia than lidocaine 3 mg kg(-1) when used for IVRA. Plasma concentrations of lidocaine decreased significantly between 5 and 60 min following tourniquet deflation, whereas blood concentrations of mepivacaine remained below the toxic concentration. (+info)
Tourniquet-induced restriction of the quadriceps muscle mechanism. Fact or fiction?
(32/227)
Many knee surgeons flex the knee and sometimes also extend the hip before inflating a tourniquet on the thigh. This practice stems from the belief that these manoeuvres prevent excessive strain on the quadriceps during surgery, the assumption being that movement of the muscle is restricted by an inflated tourniquet. We therefore examined, using ultrasound, the movement of the quadriceps muscle above and below the tourniquet before and after inflation. We applied a tourniquet of standard size to the thigh of five volunteers for approximately five minutes. A bubble of air was injected into the quadriceps muscle above the tourniquet and was the proximal point of reference. The musculotendinous junction was the distal point. The movement of the reference point was measured by ultrasound before and after inflation of the tourniquet. Each measurement was repeated with either the knee flexed and the hip extended, or the hip flexed and the knee extended. The mean and standard deviation were recorded. Before inflation the mean amount of passive movement was 1.1 +/- 0.13 cm proximal and 4.0 +/- 0.08 cm distal to the tourniquet, with a range of movement of the knee of 0 degrees to 137 degrees (6.7 degrees). After inflation the mean passive movement was 1.0 +/- 0.07 cm proximal and 4.0 +/- 0.08 cm distal to the tourniquet with a range of 0 degrees to 132 degrees (+/- 7.6 degrees). The ultrasound findings therefore have shown no evidence of restriction of the quadriceps muscle by an inflated tourniquet. (+info)