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Journal of the Irish Medical Association, April 1964., Vol. LIV. No. 332, pp. 110

W. G. FEGAN,  M.Ch., F.R.C.S.I.,         W. H. BEESLEY,  M.B., B.Ch.

D. E. FITZGERALD,  M.Sc., L.R.C.P.I., S.I.

Venous thrombosis in the lower limbs can be a crippling disease, and it may be fatal should pulmonary embolism result. The object of this paper is to formulate a comprehensive regime of prophylaxis.

It is apparent from many post mortem studies of the veins of the lower limbs that venous thrombosis in them is a much more common occurrence than the ante mortem clinical state of patients indicates. Roberts (1963), in cases of 108 consecutive deaths, performed dissections of the lower limbs after death. He found venous thrombosis in 58 cases (53%), the highest incidence being in the intramuscular veins of the soleus muscle, followed by the posterior tibial veins and then the veins of the gastrocnemius. Sulma (1949) reports 170 cases of venous thrombosis in whom 20 died; but in 14 of these 20, thrombosis was not diagnosed during life. McLachlin and Paterson (1962) describe 100 people complete post mortem dissections of pelvic and leg veins in a random series of patients - 34% of the cases had venous thrombosis. Sevitt and Gallagher (1961) state that only about one third of cases with thrombi at necropsy have relevant symptoms during life.

Much has been written about the causes of venous thrombosis - the classification from the Nomenclature of Diseases of the Blood and Lymph Vessels is probably the most comprehensive:

1. Primary -

Thromboangeitis obliterans

Recurrent or migrating

Essential

2. Secondary to -

1. Tuberculosis, syphilis, actinomycosis
2. Other bacteria

1. Varicose veins: A patient with varicose veins should always have them adequately treated, but especially before -

1. an operation
2. childbirth
3. a prolonged stay in bed, especially if associated with fever

1. Cardiac Output: Cardiac failure is one major cause of venous stasis. The patient should be treated with cardiac glycosides and diuretics.
2. Blood Volume: A low blood volume can lead to poor venous circulation with attending stasis, and maybe thrombosis. Wherever possible, this low blood volume should be anticipated and prevented.
3. Compression: The patients most susceptible to venous thrombosis fall, as a rule, into one or more of the following groups -

1. over 30 years of age
2. have varicose veins
3. have a family history of varicose veins
4. those who undergo some pelvic operation
5. women in childbirth

1. Breathing Exercises: The incidence of pulmonary embolism is relatively low in patients who have undergone thoracic surgery. These patients are encouraged most vigorously, by physiotherapists, to perform breathing exercises both before and after operation. These exercises, by means of the thoracic and abdominal venous pumps, greatly facilitate the return of blood from the lower limbs. All patients, not only those for thoracic surgery, should perform vigorous breathing exercises.
2. Leg Exercises: Most of the venous return from the lower limbs depends upon the plantar, soleal, femoral and abdominal muscle pumps. All patients should, from their first hour in hospital, receive instructions to perform exercises that will maintain these pump actions. Everyone concerned with the patients should take an active part in encouraging these exercises.
3. Ambulation: Physiological exercise is superior to all forms of "artificial" exercise. To confine pre-operative patients to bed, and to sit them in chairs both pre- and post-operatively are established customs harmful to the leg veins and should be discouraged. These measures simply increase venous stasis and endothelial injury, as has been shown in an exaggerated fashion in wartime in people who had been sitting for hours in deck-chairs in air-raid shelters. These people were prone to develop bilateral deep vein thrombosis ("bombed feet"). A patient who has efficient muscle pumps is able when walking to reduce the venous pressure in the leg veins to near zero. Whenever possible all patients, whether they be pre- or post-operative, pre- or post-partum, or medical, should be out of bed and using their leg muscles to walk or mark time.
4. Avoidance of standing: A patient standing still is marking virtually no use of his powerful muscle pumps, thus the pressure of blood in the veins of the lower limb increases and stasis ensues. The ideal is for a patient not to stand still at all. He should walk or mark time. A thrombus can form within one minute of an offence to a vein and early ambulation must be within minutes if it is to be of paramount importance.
5. Operative Procedures: In most operations the patient's calves are in contact with the operating table, encouraging local stasis and endothelial injury. All operative cases, if they fall within the groups mentioned above - who need bandages, and elastic stockings and, may it be stressed again, all delivery cases - should continue to wear the bandages and stockings during the operative procedures and for three weeks after until the period accepted as most critical for venous thrombosis has passed.

Venous thrombosis is of frequent occurrence following pelvic procedures, and some obstetricians, although performing similar manoeuvres, are more plagued with venous thrombosis than others. All pelvic procedures should be performed with the utmost care in order to minimize damage to the veins.

6. Local Anaesthetics: Wherever possible local anaesthetic should be used for minor operations in order that the patient may leave the operating table and walk immediately.
7. Recumbent Patients: An effective and inexpensive measure of promoting leg vein drainage is to raise the foot of the bed. This could be applied to almost every patient and, theoretically, should reduce the frequency of leg vein thrombosis (Morrell et al.). McLachlin et al. (1962) showed that this position was more effective in emptying the veins than was vigorous contraction of the calf and thigh muscles in an horizontal patient.

Adult patients confined to bed are comparatively inactive and prone to venous thrombosis. Conversely, children confined to bed are usually active and very seldom develop venous thrombosis. It would be ideal if every bed were equipped with a cheap form of pedalling machine with a light aluminium cradle over it. In this way a patient can exercise his legs while in bed, and thus diminish the likelihood of venous thrombosis. There should also be an overhead handle available so that the patient can regularly rotate the position from side to side. Even if unable to actually rotate themselves, the effort of attempted rotation is almost as efficient in increasing venous return from the limbs by its pumping action on the abdominal veins. We have only recently become aware of the full significance of this abdominal pump. In this department we have taken a large series of deep intravenous pressure recordings in the active patient and find that the abdominal pump is of great importance in boosting venous return from the lower limbs.

8. Increased Abdominal Pressure: A raised intra-abdominal pressure can impede venous return from the lower limbs (Ludbrook, 1962). Hughes and Goble (1962) state that intra-abdominal packs and retractors cause an increase in pressure in the leg veins, leading to increased stasis. Wherever possible tumours, cysts or ascitic fluid should be removed in order to decrease the intra-abdominal pressure, and abdominal packs and retractors should be used with the greatest of gentleness.

 

9. Painful Incisions: Painful operative or traumatic lesions are responsible for much immobility on the part of the patient. Analgesics should be used freely and in adequate dosage, to relieve the patient sufficiently to enable exercise and thus diminish the venous stasis.
10. Anti-coagulants: Much has been written on this subject. Without doubt the ideal is to put all susceptible patients on prophylactic anticoagulants, but this is impracticable when one considers the number of patients who fall into the five susceptible groups, and some cases will have contra-indications to anti-coagulant therapy.