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Query: UMLS:C0149871 (deep vein thrombosis)
 12,364 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The natural history diagnosis and immediate treatment of patients suffering from pulmonary embolism has been discussed. Anaesthetists should use their influence to bring about a high standard of prophylactic care against deep venous thrombosis and consequently of pulmonary embolism. They are likely to be involved in the resuscitation and treatment in intensive care units of those cases who suffer from major symptoms and massive emboli and some of them will rarely be involved in anaesthetising for pulmonary embolectomy aided by cardiopulmonary by-pass and, less rarely, for IVC ligation or plication and venous disobliteration. Anticoagulant drugs appear to limit the mortality of pulmonary embolism to 5%. The mortality of IVC ligation or plication varies in different reports from 2 to 50%; it should therefore be reserved for the special indications which have been discussed. There is also an incidence of recurrent pulmonary embolism after IVC ligation and plication and leg troubles from stasis in about 30% of cases. Streptokinase is usually indicated in the immediate treatment of major pulmonary emboli which cause shock and severe distress with an immediate threat to life. In hospitals having access to cardiopulmonary by-pass, pulmonary embolectomy has a small role to play in major emboli with cardiovascular collapse, if surgery can start within 2 hours and pulmonary angiography is available. Cardiopulmonary by-pass on its own may be life-saving in supporting the circulation while the clot fragments. If cardiac arrest occurs, external cardiac massage should be undertaken as it is sometimes successful and disseminates and fragments the clot in the pulmonary artery.
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PMID:Pulmonary embolism. Prophylaxis diagnosis and treatment. 97 May 90

We studied the accuracy of compression sonography in 238 patients suspected of deep venous thrombosis comparable to phlebography. The veins in the thigh were considered to be occluded when their lumen did not collapse under slight pressure with the scanner. In the lower leg, incompressible echosparse strings were regarded to be equivalent to thrombosed veins. Since in some patients both legs were submitted to phlebography, 301 x-ray-examinations of one leg were compared to ultrasound. 153 thromboses were detected by venography. Ultrasound diagnosis of venous occlusion was made with a sensitivity of 96% and a specificity of 99%. In 91% it was possible to predict the extent of the clot. Thigh vein thromboses were correctly seen with a sensitivity of 97% and a specificity of 99%. Isolated calf vein thromboses were detected with a sensitivity of 90% and a specificity of 99%. In 10% of the examinations ultrasound brought new essential information compared to phlebography. We conclude that compression sonography is an accurate method in the diagnosis of deep venous thrombosis and that it should be applied liberally in patients with suspected venous occlusions.
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PMID:[Diagnosis of acute deep leg vein thrombosis with compression ultrasonography]. 208 51

All the important abdominal veins and limbs vein can be examined. The veins, in cross-section are rounded in repletion, (maximum normal vein caliber has reached when erect) almost flat in a state of vacuous-ness. The lumen normally echofree is limited by a wall thinner and less echogenic than the wall of adjacent artery. The parietal motions are rythmed by breathing. Venous blood flow can become echogenic, with weak echoes, as snow storm within the lumen. These phenomena are often visible in venous confluent and within the lumen below occlusion where there is sludge. In supine position deep abdominal veins, limbs veins until popliteal veins are easily seen. Below the popliteal fossa in prone position the veins are nearly empty and not visible beyond pathological circumstances. Objective studies demonstrated the inaccuracy of clinical diagnosis of deep venous thrombosis, echotomography (coupled with doppler) is among the non-invasive methods the most interesting, permitting to recognize venous occlusion complete or incomplete by clot but also compression by tumour or ganglion. The compression under the probe collapse the normal vein, but if there is clot inside, the compression become incomplete or impossible. The caliber of the vein is dilated also in supine position. The richest of venous clot in red cells in comparison with arterial thrombus make it more and earlier echogenic and more especially as the investigation is performed with high frequency probe. In the same way if the clot is floating its motions are put in evidence. Echotomography make usually difference between clot and neoplastic thrombus which is again more echogenic and also have special location. Echotomography permit to follow evolution ot venous thrombosis under treatment. The wall vein lesions after thrombosis are analysed showing thickening, destruction of the cups, dilatation of some veins while others are still obstructed.
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PMID:[Ultrasonics and deep vein thrombosis. Ilio-caval level and the lower extremities]. 304 76

Between 1 July and 31 December, 1985, 53 patients, clinically suspected of having deep venous thrombosis (DVT), were prospectively studied by B-scan ultrasound prior to lower-limb venography. Criteria for a positive ultrasound examination included visualization of frank clot, failure of the vein to collapse with compression, and absence of normal phasic flow with pulse Doppler sampling. All (100%) of the contrast venograms were considered of diagnostic quality. Fifty of the 53 ultrasound examinations (94%) were considered diagnostic. Of the 50 patients having venous ultrasound of diagnostic quality, contrast venography was positive in 25 and negative in 25 for DVT. Venous ultrasound was correct in 46 patients, for an accuracy of 92% (46/50). Sensitivity was 88% (22/25), specificity was 96% (24/25), the positive predictive value was 96% (22/23), and the negative predictive value was 89% (24/27). The single most useful sign of thrombosis in ultrasound examinations was the failure of the involved vein to collapse with compression. Venous ultrasound appears to be highly accurate in the detection of deep venous thrombosis of the lower extremity.
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PMID:A prospective study of the efficacy of B-scan sonography in the detection of deep venous thrombosis in the lower extremities. 315 Mar 83

In this companion paper to "Part I: Numerical Simulations, " we report in vitro experimental studies performed on a simple model leg consisting of a "vein" of thin-walled latex tubing surrounded by "tissue" of open-pore foam rubber. Three modes of periodic external compression, were investigated: i) uniform compression; (ii) graded compression, decreasing from ankle to knee; and (iii) sequential compression, progressing from ankle to knee. The modes are compared on the basis of three hemodynamic criteria: degree of vessel collapse, level of fluid velocity, and level of shear stress. In uniform compression these measures of merit are distributed very nonuniformly along the length of the leg: they are high near the proximal end of the cuff but low elsewhere, a result due to the formation proximally of a partially occlusive throat. The latter does not form in either graded or sequential compression, with the consequence that favorable values of the three measures of merit occur more uniformly along the length of the pressurized region. It is concluded that either the graded or sequential mode of compression, or perhaps a combination of the two, would be more effective than uniform compression as a prophylaxis against deep vein thrombosis.
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PMID:Bioengineering studies of periodic external compression as prophylaxis against deep vein thrombosis-part II: experimental studies on a stimulated leg. 707 35

A nationwide surveillance of mortality associated with sterilization led to the identification of the death of a woman who was using oral contraceptives (OCs) prior to operation and died as a result of mesenteric venous thrombosis after tubal sterilization. This case is reported as a reminder of the increased risk of postoperative thromboembolism associated with OC use and to suggest how this risk can be decreased. The patient was a healthy, 24-year-old, white woman with 2 living children. She did not smoke and had no history of thromboembolic disorders. She had been using OCs for several years and continued their use until the time of hospitalization for operation. The specific OC preparation she was using is unknown. The first 48 hours following the operation the patient did well except for some mild to moderate lower abdominal pain. On the 4th day, she developed severe, acute abdominal pain and suffered a cardiovascular collapse for which she required resuscitation. She was considered to be septic and dehydrated; thus, treatment with intravenous fluids and antibiotics was initiated. An echogram obtained on the 5th day after sterilization suggested the possibility of an abdominal mass on the right sight, and an exploratory laparotomy was performed. There was 2000 ml of clear fluid in the peritoneal cavity. The cecum and ascending colon were necrotic with thrombosis of the colic and ileocolic veins. The pelvis and the appendectomy stump appeared normal. A right hemicolectomy and resection of the distal ileum were performed followed by a primary side-to-side ilecolostomy. The patient's condition deteriorated after laparotomy despite vigorous management, and she died the next morning, 7 days after the sterilization operation. Significant findings at postmortem examinations were thrombosis of both the ileocolic vein and the superior mesenteric vein and inflammation in the area of colon adjacent to the anastomosis. The cause of death was determined to be endotoxic shock secondary to large bowel necrosis which resulted from thrombosis of the mesenteric veins. This patient was at increased risk for postoperative venous thrombosis because she continued to use OCs during the month before the operation. 2 carefully conducted case-control studies have shown that OCs increase by more than 3-fold the risk of postoperative thromboembolism. It is unclear how much the knowledge of this risk has altered preoperative management of women having elective operation in the U.S. At least 1 prospective study has found no difference in incidence of idiopathic deep venous thrombosis with increasing estrogen doses, but the risk of postoperative thromboembolism associated with OCs containing a lower estrogen content has not been studied.
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PMID:Oral contraceptives and postoperative venous thrombosis. 708 37

The history and physical examination were assessed in 215 patients with acute pulmonary embolism uncomplicated by preexisting cardiac or pulmonary disease. The patients had been included in the Urokinase Pulmonary Embolism Trial or the Urokinase-Streptokinase Embolism Trial. Presenting syndromes were (1) circulatory collapse with shock (10 percent) or syncope (9 percent); (2) pulmonary infarction with hemoptysis (25 percent) or pleuritic pain and no hemoptysis (41 percent); (3) uncomplicated embolism characterized by dyspnea (12 percent) or nonpleuritic pain usually with tachypnea (3 percent) or deep venous thrombosis with tachypnea (0.5 percent). The most frequent symptoms were dyspnea (84 percent), pleuritic pain (74 percent), apprehension (63 percent) and cough (50 percent). Hemoptysis occurred in only 28 percent. Dyspnea, hemoptysis or pleuritic pain occurred separately or in combination in 94 percent. All three occurred in only 22 percent. The most frequent signs were tachypnea (respiration ate 20/min or more) (85 percent), tachycardia (heart rate 100 beats/min or more) (58 percent), accentuated pulmonary component of the second heart sound (57 percent) and rales (56 percent). Signs of deep venous thrombosis were present in only 41 percent and a pleural friction rub was present in only 18 percent. Either dyspnea or tachypnea occurred in 96 percent. Dyspnea, tachypnea or deep venous thrombosis occurred in 99 percent. As a group, the identified clinical manifestations, although nonspecific, are strongly suggestive of acute pulmonary embolism. Conversely, acute pulmonary embolism was rarely identified in the absence of dyspnea, tachypnea or deep venous thrombosis.
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PMID:History and physical examination in acute pulmonary embolism in patients without preexisting cardiac or pulmonary disease. 746 69

Prevention of deep venous thrombosis is fundamental in the prevention of pulmonary embolism. Deep venous thrombosis is common after all surgical procedures, but the frequency differs, as does the effectiveness of various methods of prevention. Low-dose heparin, low molecular weight heparin, graduated compression elastic stockings, intermittent pneumatic compression, and oral anticoagulants have a role in the prevention of deep venous thrombosis, depending on the risks of deep venous thrombosis and their demonstrated effectiveness (or lack of effectiveness) in the particular circumstance. The optimal method of prophylaxis is specific to the predisposing condition. Heparin continues to be a mainstay of anticoagulant therapy. Major bleeding is rare in patients treated with low doses of heparin to prevent deep venous thrombosis. With therapeutic doses, however, major bleeding occurs in about 5% of patients. The optimal dose of warfarin and the method of evaluating the anticoagulant effect of warfarin have undergone modifications in recent years. It is now recognized that the prothrombin time ratio depends on the activity of the thromboplastin used for measuring the prothrombin time. An International Normalized Ratio, which relates to a standardized thromboplastin, has been developed, thus avoiding differences of the prothrombin time ratio that occur from batch to batch of thromboplastin reagent from the same manufacturer and that occur with different thromboplastin reagents from different animal sources and different manufacturers. The bedside diagnosis of pulmonary embolism is useful in helping a physician determine the extent to which diagnostic tests should be pursued. A sound bedside impression also contributes strongly to the formulation of a noninvasive diagnosis of pulmonary embolism. The clinical manifestations of pulmonary embolism form a recognizable constellation of findings that often lead to a correct diagnosis or exclusion of pulmonary embolism. Important clues to the diagnosis of pulmonary embolism relate to the initial syndrome. The presentation of pulmonary embolism is most often in the form of the pulmonary hemorrhage-pulmonary infarction syndrome. The next most common presentation is unexplained dyspnea, unaccompanied by pulmonary hemorrhage or infarction. Least common, but most severe, is the syndrome of circulatory collapse. Immobilization, usually caused by surgery, is the most frequent predisposing factor. Most patients with clinically recognizable pulmonary embolism have dyspnea or tachypnea. Dyspnea or tachypnea or pleuritic pain occurs in nearly all patients who have clinically apparent pulmonary embolism (97%). Ordinary tests such as the electrocardiogram and chest radiograph are helpful if the physician is attentive to nonspecific abnormalities.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Acute pulmonary embolism. 807

This work is to establish theoretical and experimental relationships for the scale-up of Immobilized Metal Affinity Chromatography (IMAC) and Immuno Affinity Chromatography for the low cost production of large quantities of Protein C. The external customer requirements for this project have been established for Protein C deficient people with the goal of providing prophylactic patient treatment. Deep vein thrombosis is the major symptom for protein C deficiency creating the potential problem of embolism transport to important organs, such as, lung and brain. Gel matrices for protein C separation are being analyzed to determine the relationship between the material properties of the gel and the column collapse characteristics. The fluid flow rate and pressure drop is being examined to see how they influence column stability. Gel packing analysis includes two considerations; one is bulk compression due to flow rate, and the second is gel particle deformation due to fluid flow and pressure drop. Based on the assumption of creeping flow, Darcy's law is being applied to characterize the flow through the gel particles. Biot's mathematical description of three-dimensional consolidation in porous media is being used to develop a set of system equations. Finite difference methods are being utilized to obtain the equation solutions. In addition, special programs such as finite element approaches, ABAQUS, will be studied to determine their application to this particular problem. Experimental studies are being performed to determine flow rate and pressure drop correlation for the chromatographic columns with appropriate gels. Void fraction is being measured using pulse testing to allow Reynolds number calculations. Experimental yield stress is being measured to compare with the theoretical calculations. Total Quality Management (TQM) tools have been utilized to optimize this work. For instance, the "Scatter Diagram" has been used to evaluate and select the appropriate gels and operating conditions via Taguchi techniques. Targeting customer requirements under the structure of TQM represents a novel approach to graduate student research in an academic institution which is designed to simulate an industrial environment.
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PMID:Gel compression considerations for chromatography scale-up for protein C purification. 988 51

External pneumatic compression of the lower legs is effective as prophylaxis against deep vein thrombosis. In a typical application, inflatable cuffs are wrapped around the patient's legs and periodically inflated to prevent stasis, accelerate venous blood flow, and enhance fibrinolysis. The purpose of this study was to examine the stress distribution within the tissues, and the corresponding venous blood flow and intravascular shear stress with different external compression modalities. A two-dimensional finite element analysis (FEA) was used to determine venous collapse as a function of internal (venous) pressure and the magnitude and spatial distribution of external (surface) pressure. Using the one-dimensional equations governing flow in a collapsible tube and the relations for venous collapse from the FEA, blood flow resulting from external compression was simulated. Tests were conducted to compare circumferentially symmetric (C) and asymmetric (A) compression and to examine distributions of pressure along the limb. Results show that A compression produces greater vessel collapse and generates larger blood flow velocities and shear stresses than C compression. The differences between axially uniform and graded-sequential compression are less marked than previously found, with uniform compression providing slightly greater peak flow velocities and shear stresses. The major advantage of graded-sequential compression is found at midcalf. Strains at the lumenal border are approximately 20 percent at an external pressure of 50 mmHg (6650 Pa) with all compression modalities.
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PMID:The effects of external compression on venous blood flow and tissue deformation in the lower leg. 1063 54


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