الفهرس | Only 14 pages are availabe for public view |
Abstract - II) - .SUMMARY The deep venous thrombosis develop most commonly in the lower limb, mostly, in the left one, mostly, in the .soleal venous sinuses. The upper Ijmb is almost immune from post operative vein thrombosis, mostly due to .the speed at which the blood flows in the upper limb; which is double what is in the lower limb veins, therefore measures to combat venous stasis in the lower.limbs ought to reduce the risk of deep vein thrombosis. The availabie methods of avoiding a thrombus in the deep veins of the lower limbs and SUbsequent pulmonary embolus after surgical operation are not successful. The prevention of deep vein thrombosis by routinely abolishing the power of the blood to clot throughout the entire venous system at the body by giving anticoagulant drugs is clumsy because the risk is Virtually confined to the veins of the lower limbs. Morever, this method carries a complication of its own as sponta~eous haemorrhage. - II4 - The risk of deep vein thro.bosis which occurs while the patient is undergoing the operation can be reduced by routinely elevating thepatient’8 legs I5° above the horizontal; or by routinely 8timulatin,~ the calf muscles by galvanic current at an electrical :pressure of I20 volts and a rate of 30 shock per minute. Ven’Jus stasis is avoided by these measures. from the most commonproph;rlactic measures against occurrence of deep venous thrombos:ls, five methods are in cOJlllJluosne: ’Aspirin” Low molecular weight dextran, Minidose of,heparin, Bilateral intermittent pneumatic compression, and Elastic compression stockings. Minidose heparin and elastic stockings, gives good prophylaxis than heparin alone. Also, intermittent pneumatic compretssion, gives a good degree of prophylaxis as it was fOtlnd that beside, reducing venous stasis, it also stimulates l’ibrinolysis. Patients who are at very h:l,ghrisk of developing venous thrombosis and embolisation in the post operative period (Old ag~, Severe trauma ,orN:a;jorsU’rgery, Previous - II5 - history ’of thromboembolism, and Ob,esity) should be given prophylaxis by full .perioperative lanticoagulation. Patients at very low risk (Child having lIin’Jr, o.peration), do not need .pro.phylaxis.For the majority of s11rgioal .patients who fall between these two extremes, the b,’nefits of .pro.phylaxis remains in question. ” , A oarefull history and eX8I1linationshould be made in all .patients with sym.ptoms and /ligns of acute venous thrombosis to exclude other condi t:Lons. Less than 50 .per cent with these signs and sym.ptoms have venous thrombosis. It venogra.phy is the only objeotivE! test available; it should be performed on all .patients with leg sym.ptoms and signs oom.patible with venous thrombosis. Clinical suspicion of VenO\;lSthrombosis can be exoluded or confirmed by perform~: impedanoeplythesmogra. phy alone or with fibrinogen leg scanning. If impedance plythesmography is positive (in absenoe of conditions known to .produce a false’positiveresults), a confident diagnosis - II6 - of venous thrombosis~an be made w1d the patient treated appropriately. If it is negative, -;he clinician has two alternatives; Either to repeat it Or to do Iodine -I25- fibrinogen soanning of the leg to deteot active venous thrombosis. The use of impedance plythesmography alone is ,based on the supposition that calf vein thrombosis which is not detected by impedanoe plythElsmography does not require treatment ,unless it extends., • Primary prophylaxis ,using drugs or physical therapy whioh are effective against deep venous thrombosis especially of lower limb, which are the main source of emboli. • Early detection of subclinioal venous thrombosis by screening patients (e.g. postoperative leg scanning with iodine -I25- fibrinogen) which provide the opportunity for treating silent thrombosis early before they embolize. Primary prophylaxis ,is likely to be the more effective and - II7 - le.s expensive approaches. Treatment ot venous thromb.)elDbolism, essentially by antiooagulation; initially by h.,parin either by intermittent intravenous heparin in a de).e ot 5000 I.U./ tour hours r so.ooc I.U./ day), or cont:lJluousintravenous heparin ad3usted to JDaintain partial throal)oplastin time between 1.5 and 2 time. the preheparin con1;rol value, and this is pretered because. the interJDittent JLntravenoU8heparin therapy is associated with higher risk otllleeding. Heparin therapy should con1;inuedtor 7 - 10 days, tor a.thrombus to adhere to the vej~ wall. The initial heparin therapJ’ is tollo.ed by a long terJDanticoagulant (oral) therapy, wartarin sodiUlllin a dose ot 10 mgper day, atter 7 d~.lot heparin therapy, and both drUgs are administered tOI?;etherfor at least 4 to 5 days. After initial dose ot wartarj~ the dose is adjusted by monitoring prothrombin time at 1.25 times the control value, and this regimen continued for at least 2 to J months. - !IB - Fibrinolytio drugs as strep”tokinase and urokinase are used to ensure lysis of thrombi and emboli, and restore oirculation, but it has its ownoomJplioations and oontraindications. Su~gioal interferenoe is l~nited to the special oomplioated c•• es and includel’rranisposition of valves , Thrombectomy,and Inferior vena cay,al interruption. |