Evaluation of the diagnostic value of the tourniquet test in predicting severe dengue cases in a population from Belo Horizonte, State of Minas Gerais, Brazil

Introduction Dengue is prevalent in many tropical and sub-tropical regions. The clinical diagnosis of dengue is still complex, and not much data are available. This work aimed at assessing the diagnostic accuracy of the tourniquet test in patients with suspected dengue infection and its positivity in different classifications of this disease as reported to the Information System for Notifiable Disease in Belo Horizonte, State of Minas Gerais, Brazil between 2001 and 2006. Methods Cross-section analysis of the diagnostic accuracy of the tourniquet test for dengue, using IgM-anti-DENV ELISA as a gold standard. Results We selected 9,836 suspected cases, of which 41.1% were confirmed to be dengue. Classic dengue was present in 95.8%, dengue with complications in 2.5% and dengue hemorrhagic fever in 1.7%. The tourniquet test was positive in 16.9% of classic dengue cases, 61.7% of dengue cases with complications and 82.9% of cases of dengue hemorrhagic fever. The sensitivity and specificity of the tourniquet test were 19.1% and 86.4%, respectively. Conclusions A positive tourniquet test can be a valuable tool to support diagnosis of dengue where laboratory tests are not available. However, the absence of a positive test should not be read as the absence of infection. In addition, the tourniquet test was demonstrated to be an indicator of dengue severity.

Isolated limb perfusion: distinct tourniquet and tumor necrosis factor effects on the early hemodynamic response.

HYPOTHESIS: Recent evidence indicates that tumor response rates after isolated limb perfusion (ILP) are improved when tumor necrosis factor (TNF) is added to the locoregional perfusion of high doses of chemotherapy. Other factors, related to the patient or the ILP procedure, may interfere with the specific role of TNF in the early hemodynamic response after ILP with TNF and high-dose chemotherapy. DESIGN: Case-control study. SETTING: Tertiary care university hospital. PATIENTS: Thirty-eight patients with a locoregionally advanced tumor of a limb treated by ILP with TNF and high-dose chemotherapy (TNF group) were compared with 31 similar patients treated by ILP with high-dose chemotherapy alone (non-TNF group). INTERVENTIONS: Swan-Ganz catheter hemodynamic recordings, patients' treatment data collection, and TNF and interleukin 6 plasma level measurements at regular intervals during the first 36 hours following ILP. MAIN OUTCOME MEASURES: Hemodynamic profile and total fluid and catecholamine administration. RESULTS: In the TNF group, significant changes were observed (P<.006): the mean arterial pressure and the systemic vascular resistance index decreased, and the temperature, heart rate, and cardiac index increased. These hemodynamic alterations started when the ILP tourniquet was released (ie, when or shortly after the systemic TNF levels were the highest). The minimal mean arterial pressure, the minimal systemic vascular resistance index, the maximal cardiac index, the intensive care unit stay, and the interleukin 6 maximal systemic levels were significantly (P<.001 for all) correlated to the log(10) of the systemic TNF level. In the non-TNF group, only a brief decrease in the blood pressure following tourniquet release and an increase in the temperature and in the heart rate were statistically significant (P<.006). Despite significantly more fluid and catecholamine administration in the TNF group, the mean arterial pressure and the systemic vascular resistance index were significantly (P<.001) lower than in the non-TNF group. CONCLUSIONS: Release of the tourniquet induces a blood pressure decrease that lasts less than 1 hour in the absence of TNF and that is distinct from the septic shock-like hemodynamic profile following TNF administration. The systemic TNF levels are correlated to this hemodynamic response, which can be observed even at low TNF levels.

The influence of tourniquet use and operative time on the incidence of deep vein thrombosis in total knee arthroplasty

OBJECTIVE: To evaluate the association between tourniquet and total operative time during total knee arthroplasty and the occurrence of deep vein thrombosis. METHODS: Seventy-eight consecutive patients from our institution underwent cemented total knee arthroplasty for degenerative knee disorders. The pneumatic tourniquet time and total operative time were recorded in minutes. Four categories were established for total tourniquet time: <60, 61 to 90, 91 to 120, and >120 minutes. Three categories were defined for operative time: <120, 121 to 150, and >150 minutes. Between 7 and 12 days after surgery, the patients underwent ascending venography to evaluate the presence of distal or proximal deep vein thrombosis. We evaluated the association between the tourniquet time and total operative time and the occurrence of deep vein thrombosis after total knee arthroplasty. RESULTS: In total, 33 cases (42.3%) were positive for deep vein thrombosis; 13 (16.7%) cases involved the proximal type. We found no statistically significant difference in tourniquet time or operative time between patients with or without deep vein thrombosis. We did observe a higher frequency of proximal deep vein thrombosis in patients who underwent surgery lasting longer than 120 minutes. The mean total operative time was also higher in patients with proximal deep vein thrombosis. The tourniquet time did not significantly differ in these patients. CONCLUSION: We concluded that surgery lasting longer than 120 minutes increases the risk of proximal deep vein thrombosis.

Use of dextran sulfate in tourniquet-induced skeletal muscle reperfusion injury.

BACKGROUND Lower extremity ischemia-reperfusion injury (IRI)-prolonged ischemia and the subsequent restoration of circulation-may result from thrombotic occlusion, embolism, trauma, or tourniquet application in surgery. The aim of this study was to assess the effect of low-molecular-weight dextran sulfate (DXS) on skeletal muscle IRI. METHODS Rats were subjected to 3 h of ischemia and 2 or 24 h of reperfusion. To induce ischemia the femoral artery was clamped and a tourniquet placed under the maintenance of the venous return. DXS was injected systemically 10 min before reperfusion. Muscle and lung tissue samples were analyzed for deposition of immunoglobulin M (IgM), IgG, C1q, C3b/c, fibrin, and expression of vascular endothelial-cadherin and bradykinin receptors b1 and b2. RESULTS Antibody deposition in reperfused legs was reduced by DXS after 2 h (P < 0.001, IgM and IgG) and 24 h (P < 0.001, IgM), C3b/c deposition was reduced in muscle and lung tissue (P < 0.001), whereas C1q deposition was reduced only in muscle (P < 0.05). DXS reduced fibrin deposits in contralateral legs after 24 h of reperfusion but did not reduce edema in muscle and lung tissue or improve muscle viability. Bradykinin receptor b1 and vascular endothelial-cadherin expression were increased in lung tissue after 24 h of reperfusion in DXS-treated and non-treated rats but bradykinin receptor b2 was not affected by IRI. CONCLUSIONS In contrast to studies in myocardial infarction, DXS did not reduce IRI in this model. Neither edema formation nor viability was improved, whereas deposition of complement and coagulation components was significantly reduced. Our data suggest that skeletal muscle IRI may not be caused by the complement or coagulation alone, but the kinin system may play an important role.

Refinement of tourniquet-induced peripheral ischemia/reperfusion injury in rats: comparison of 2 h vs 24 h reperfusion.

Prolonged ischemia of skeletal muscle tissue, followed by reperfusion, leads to ischemia/reperfusion injury (IRI), which is a feared local and systemic inflammatory reaction. With respect to the 3Rs, we wanted to determine which parameters for assessment of IRI require a reperfusion time of 24 h and for which 2 h of reperfusion are sufficient. Rats were subjected to 3 h of hind limb ischemia and 2 h or 24 h of reperfusion. Human plasma derived C1 inhibitor was used as a drug to prevent reperfusion injury. For 2 h of reperfusion the rats stayed under anesthesia throughout (severity grade 1), whereas for 24 h they were awake under analgesia during reperfusion (grade 2). The femoral artery was clamped and a tourniquet was placed, under maintenance of venous return. C1 esterase inhibitor was systemically administered 5 min before the induction of ischemia. No differences in local muscle edema formation and depositions of immunoglobulin G and immunoglobulin M were observed between 2 h and 24 h (P > 0.05), whereas lung edema was only observed after 24 h. Muscle viability was significantly lower after 24 h vs 2 h reperfusion (P < 0.05). Increased plasma creatine kinase (CK)-MM and platelet-derived growth factor (PDGF)-bb could be detected after 2 h, but not after 24 h of reperfusion. By contrast, depositions of C3b/c and fibrin in muscle were only detected after 24 h (P < 0.001). In conclusion, for a first screening of drug candidates to reduce IRI, 2 h reperfusions are sufficient, and these reduce the severity of the animal experiment. Twenty-four-hour reperfusions are only needed for in-depth analysis of the mechanisms of IRI, including lung damage.

Outflow occlusion for circulatory arrest in dogs

The purpose of this study was to evaluate the possibility of producing circulatory arrest by occlusion of the pulmonary trunk as an alternative to the venous inflow occlusion through the left hemithorax. Eight healthy mongrel dogs were divided in two groups. Group I underwent 4 minutes of outflow occlusion and Group II was submitted to 8 minutes of circulatory arrest. Outflow occlusion was performed through left thoracotomy and pericardiotomy by passing a Rumel tourniquet around the pulmonary trunk. Physical examination, electrocardiography, echocardiography, blood gas analyses, hemodynamic, and oxygen transport variables were obtained before and after the procedure. The dogs from Group I did not have any clinical, electrocardiographic, echocardiographic, or hemo-dynamic abnormalities after anesthetic recover. In the Group II, only one dog survived, which had no clinical, electrocardiographic, or echocardiographic abnormalities. In this last dog, just after releasing the occlusion, it was detected increases in the following parameters: heart rate (HR), systolic, diastolic and mean arterial blood pressure (SAP; DAP; MAP), pulmonary artery pressure (PAP), pulmonary wedge pressure (PWP), central venous pressure (CVP), cardiac output (CO), systolic index (SI), cardiac index (CI), left and right ventricular stroke work (LVSW; RVSW), oxygen delivery index (DO2), oxygen consumption index (VO2), and oxygen extraction (O2 ext). Moreover, the oxygen content of arterial and mixed venous blood (CaO2; CvO2), and the arterial and mixed venous partial pressure of oxygen (PaO2; PvO2) were decreased 5 minutes after circulatory arrest. Outflow occlusion is a feasible surgical procedure for period of 4 minutes of circulatory arrest.

Accidents caused by Bothrops and Bothropoides in the State of Paraiba: epidemiological and clinical aspects

INTRODUCTION: Bothrops and Bothropoides snakes cause 70% of the ophidic accidents in Brazil. The species that cause ophidic accidents in State of Paraíba are Bothropoides erythromelas, Bothrops leucurus and Bothropoides neuwiedi. METHODS: This is a prospective and transverse study, following a quantitative approach of accidents involving Bothrops and Bothropoides admitted to the Toxicological Assistance and Information Centers of Campina Grande and João Pessoa (Ceatox-CG and Ceatox-JP), aimed at identifying the epidemiological and clinical profile of such accidents. All of the patients admitted had medical diagnoses and were monitored at Ceatox-CG or Ceatox-JP. RESULTS: The genera Bothrops and Bothropoides caused 91.7% of the ophidic accidents reported. Snake bites were frequent in men (75.1%), rural workers (65.1%), literate individuals (69%) between 11 and 20 years-old (21.7%), and toes the most common area attacked (52.7%). Most (86.6%) patients were admitted within 6 hours after the accident/bite, with a predominance of mild cases (64.6%). The annual occurrence in Paraíba was 5.5 accidents/100,000 inhabitants and lethality was 0.2%. CONCLUSIONS: Positive changes in the profiles of these accidents were verified, such as the non-application of inadequate solutions, including the use of tourniquet, coffee grounds, garlic, suction and/or cutting the bitten area. Moreover, the Itinerant Laboratory project, linked to Paraíba State University in partnership with Ceatox-CG, has contributed positively, providing several cities of the state with information regarding the prevention of accidents involving venomous animals. The local press has also contributed, reporting the educational work developed by the centers.

Subclinical femoral neuropathy after anterior cruciate ligament reconstruction

Background and aim of the study: Patients with anterior cruciate ligament (ACL) reconstruction and femoral catheter analgesia may develop quadriceps amyotrophy. We aimed to determine whether this amyotrophy might be related to a femoral neuropathy. Material and method: After Ethical Committee approval and patients' written informed consent, 17 patients ASA I and II scheduled to undergo ACL reconstruction were recruited. An electromyography (EMG) was performed before the operation in order to exclude a femoral neuropathy. A femoral nerve catheter was inserted before the surgery with the aid of a nerve stimulator, and 20 ml of 0.5% ropivacaine was injected. The operation was done under spinal or general anaesthesia. Postoperative analgesia was provided with 0.2% ropivacaine for 72 hours, in association with oxycodone, paracetamol and ibuprofen. A second EMG was performed 4 weeks after the ACL repair. A femoral neuropathy was defined as a reduction of the surface of the motor response of more than 20%, compared to the first EMG. A third EMG was performed at 6 months if a neuropathy was present. Results: Mean age of this group of patients was 27 years old (range 18-38 y.). Among the 17 patients, 4 developed a transient femoral neuropathy (incidence of 24%) without clinical complain. Conclusion: In this study, the incidence of subclinical femoral neuropathy after ACL reconstruction is high. This lesion may be caused by the femoral catheter (mechanical damage, toxicity of local anaesthesia) or by the Tourniquet. Further studies are needed to investigate the incidence of subclinical neuropathy, according to the type of analgesia (epidural analgesia, PCA) and surgery.

Anaesthesia for electroconvulsive therapy: time for a change?

Introduction: Electroconvulsive therapy (ECT) may be used to treat severe depression and needs a specific general anaesthesia. Important cardiovascular changes occur during the ECT with a parasympathetic induced bradycardia followed by a sympathetic response. A dedicated protocol was designed 6 years ago. The goal of this study was to analyse the management of anaesthesia for ECT in our institution, the adherence to the protocol and the occurrence of adverse events during anaesthesia. Methods: After Institutional Ethics Committee approval, we conducted a retrospective analysis of our anaesthesia protocol for patients scheduled for electroshock therapy during a five years period (2004- 2008). The protocol includes administration of atropine subcutaneously 30 minutes before the procedure, followed by general anaesthesia induced with etomidate (0.2 mg/kg). Suxamethonium (1 mg/kg) is administered after the inflation of a pneumatic tourniquet on the opposite arm, in order to observe the electroshocks convulsive effects. The psychiatrist initiates the convulsive crisis once curarisation is achieved. Face mask ventilation is then applied during the post-ictal phase with closed blood pressure monitoring. : 228 ECT were performed in 25 patients. The median dosage of etomidate was 0.37 mg/kg and suxamethonium 1.20 mg/kg. Hypertension during the ECT procedure was present in 62.7% of cases, tachycardia 23.2% and bradycardia 10.5%. Esmolol was administered in 73.4% of hypertensive patients in a range of 0 to 30 mg. The protocol was followed in half of the cases in regards to atropine administration (50.4%). We observed a significant increase of hypertension (73.9%, p = 0.001) after atropine administration, without effect on heart rate. Conclusions: The management of anaesthesia for ECT is specific and follows a predefined protocol in our institution. Adherence to our protocol was poor. Adverse events are frequent and significant association between the administration of atropine and the incidence of hypertension as well as poor protocol adherence implies reconsideration of our anaesthesia protocol for electroconvulsive therapy and better quality control of the clinical practice.

Controversias en artroplastia total de rodilla

Total knee replacement (TKR) is an operation that has radically improved the quality of life of millions of people during the last decades. However, some technical details, concerning the surgical procedure, are still a matter of a strong debate. In this review of the literature, we have included the best evidence available of the last decade, related to TKR surgery like the use of tourniquet during operation, patellar resufacing, all-polyethilene tibial component, cemented or cementless fixation, mobile bearings, or posterior-stabilized versus cruciate-retaining prosthesis.