The effects of peroperative electrical calf muscle stimulation with groups of impulses giving a short lasting tetanus of the calf muscles on postoperative deep venous thrombosis (DVT) and pulmonary embolism (PE) were compared with that of dextran 40 given per and postoperatively. The incidence of DVT and PE during the first 4-6 postoperative days was recorded. The diagnosis of DVT was based on the 125I-fibrinogen uptake test and phlebography and of PE on pre- and postoperative perfusion pulmonary scintigram and chest X-ray examination. Both methods reduced the incidence of PE. Calf muscle stimulation reduced the DVT incidence in patients with malignant disease while the reduction in DVT incidence for the whole group only was significant in the stimulation as well as the dextran 40 group. Mean values for preoperatively determined levels of antithrombin III, beta-thromboglobulin, fibrinopeptide A, plasminogen and ability to release fibrinolytic activity during venous stasis did not differ between those patients who developed or those who did not develop postoperative DVT or PE. However, antithrombin III levels below 80 per cent appeared to predispose to postoperative thromboembolism. The two prophylactic methods have similar effects on the incidence of postoperative thromboembolism. The stimulation method has certain advantages due to its safety and simplicity.
In order to compare two types of long, soft central venous catheters with the same stiffness, 39 silicone elastomer (SE) and 36 polyurethane (PU) catheters were inserted in 75 patients via basilic or cephalic veins punctured at the cubital fossa. Mean duration of catheterization was 10.5 days. Scanning electron microscopy revealed that the SE catheters to have a more uniform, but somewhat rougher surface topography than the PU catheters. The platelet adhesion in vitro to the SE catheters was four times higher than to the PU catheters. The incidence of clinical thrombophlebitis in the arm veins was 36% with the SE catheters, and 5.5% with the PU catheters (p less than 0.01). No significant differences were found between the SE and PU catheters regarding the number and size of radiologic thrombi in the peripheral and central veins, catheter occlusion rate, and platelet adhesion to the inner side of the catheter tip at withdrawal. Platelet adhesion in vivo correlated with the duration of catheterization in both groups of catheters. Mechanical trauma to the vein endothelium seems to be of vital importance in thrombus formation, but not in the induction of clinical thrombophlebitis.
Central venous catheters of two types were inserted through basilic or cephalic veins punctured at the fossa cubiti in 61 patients: 39 soft silicone elastomer (S.E.) and 22 stiffer polyethylene (P.E.) catheters were compared regarding their thrombogenicity. Mean duration of catheterization was 6.5 days. Radiological thrombi in the peripheral and central veins visualized by phlebography were significantly smaller, and the incidence of the mural thrombi in the central veins significantly lower with the S.E. than with the P.E.-catheters, but the use of S.E.-catheters did not reduce the incidence of clinical thrombophlebitis in arm veins: 14 cases in the group with S.E. and four in that with P.E.-catheters. In both groups, the maximum incidence of clinical thrombophlebitis occurred 4-8 days after catheterization. Later, there seems to be a low risk for the appearance of clinical thrombophlebitis with both catheters. Neither the surface topography of the catheter materials, nor the platelet adhesion on their surfaces in contact with human blood in vitro offered conclusive arguments for interpretation of their thrombogenicity in vivo. Catheter stiffness seems to play an important role in inducing mural thrombus formation in central venous cannulation in man.
The efficiency of double contrast barium enema and flexible rectosigmoidoscopy (to 60 cm) in the assessment of patients with a positive Hemoccult II test in a randomized screening study for colorectal neoplasms was evaluated. A positive test was present in 625 patients, of whom 530 had a complete enema and rectosigmoidoscopic assessment. A carcinoma was diagnosed in 26 and an adenoma greater than or equal to 1 cm in diameter in 71. As a control, 323 patients with a negative assessment repeated the Hemoccult II test and of these 67 had a positive second test, of whom 55 underwent colonoscopy. One carcinoma (Dukes' A) and two adenomas greater than or equal to 1 cm in diameter were diagnosed. The efficiency of the assessment was also checked by rescreening the whole group 1-2 years after the first study and by continuing follow-up. It was found that two more carcinomas and one adenoma greater than or equal to 1 cm in diameter had been overlooked at the primary assessment. The sensitivity for neoplasms greater than or equal to 1 cm in diameter at the primary assessment was 72 per cent for double contrast barium enema and 86 per cent for rectosigmoidoscopy. The sensitivity for the combined methods was 94 per cent and the specificity was 99 per cent. The combination of double contrast barium enema and rectosigmoidoscopy in the primary assessment of patients with a positive Hemoccult II test gives an acceptable result and immediate retesting of those with a negative assessment is not necessary.
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