[Intentional normovolemic hemodilution in the medical treatment of lower limb arteritis]

Improvement in Blood Supply After "Heparin-Dextran" Therapy in Patients of Buerger's Disease with Critical Limb Ischemia

Alleviating the agonizing pain of critical limb ischemia (CLI) in patients of Buerger's disease (BD) has been challenging, due to lack of definitive treatment; "Heparin-Dextran" infusion has been tried in this study. Assessment of clinical improvement and vascular changes following therapy. Patients with CLI admitted to emergency surgical ward were studied prospectively. BD was diagnosed by Shionoya's criteria, and confirmed by digital subtraction angiography (DSA). Heparin and Dextran intravenous infusion was administered for 10 days. Severity of rest pain, ischemic changes in the feet, claudication distance and ankle brachial index (ABI) were estimated prior to therapy, at completion and 3 weeks after therapy. Vascular changes were assessed by CT angiography (CTA) performed prior to and 3 weeks after therapy. Twenty consecutive patients were studied. Successful hemodilution reflected by decreased hematocrit (37.4 % to 32.6 %, p < 0.05) and increased mean ABI (0.46 to 0.83, p < 0.01), improved rest pain in 75 % patients (p < 0.001), increased claudication distance in 94 % (p < 0.05) and ulcers healing in 70 % patients. CTA revealed recanalised vessels (decreased length of occluded segments) in 10 (50 %, p = 0.005), increased collaterals in 12 (60 %, p < 0.01) and improved distal run-off in 13 (65 %, p < 0.01) patients. "Heparin-Dextran" therapy in patients of CLI from BD improves tissue perfusion by increasing collaterals and recanalisation of vessels, resulting in significant relief from rest pain and clinical improvements. CTA is as efficacious as DSA for evaluation of BD.

Effects of haemodilution and rewarming with regard to digital amputation in frostbite injury: an experimental study in the rabbit

Peripheral vascular failure with haematological and haemodynamic changes occurs after frostbite injuries. In order to study the effects of normovolemic haemodilution on the extent of digital necrosis, the paws of rabbits were haemodiluted and frozen to -15 degrees C. Dextran or gelatin was used as the plasma substitute in two groups and the rewarming after the cold injury was performed either at room temperature (22 degrees C) or with hot water baths (38 degrees C). The extent of necrosis was significantly less in the rabbits haemodiluted with dextran or gelatin and rewarmed in hot water baths.

[In vivo rheologic studies of plasma substitutes]

The aim of this study was to compare in 60 ASA1 patients, the rheological effects of a 500 ml plasma substitute infusion at induction of general anaesthesia. The 60 patients were allocated into 6 groups of 10. Each group received either albumin 4%, or dextran 40 3.5%, or dextran 60 6%, or hydroxyethylstarch (HES) 200 6%, or modified fluid gelatin or Ringer lactate. The infusion extended over 30 minutes. In blood samples obtained before infusion, immediately after the end, three and 24 hours after the end of infusion, osmotic pressure, oncotic pressure, proteins and fibrinogen concentration were measured. Following rheological parameters were also assessed: plasma viscosity, blood viscosity at two shear rates (0.5 and 128 s-1), erythrocyte aggregation by primary and final aggregation times as well as total and partial dissociation thresholds. The determinations were carried out at haematocrit corrected to 40%. At intergroup analysis of the different substitutes compared to albumin 4%, with the exception of Ringer lactate, there was no significant modification of osmotic and oncotic pressures or fibrinogen concentrations. Only gelatin and dextran 60 modified the rheological parameters. The intragroup comparison did not demonstrate significant variations of osmotic and oncotic pressures. Fibrinogen concentrations remained unchanged up to the 24th hours, where they increased as a reaction to surgery. Similar changes of rheological parameters occurred for Ringer lactate, albumin 4% and dextran 40: decrease of plasma viscosity (< 10%) and blood viscosity (< 20% at shear rate of 0.5 s-1), increase of primary aggregation time (30-50%) with decrease of total dissociation threshold (10-20%). These changes ended 24 hours after infusion. Dextran 60 and gelatin elicited a modification of blood rheology until the 24th hour after the end of infusion. Such modifications did not occur with HES. It is concluded that when a rheological effect is required albumin 4% or dextran 40 3.5% should be used.

[Original technic for preoperative hemodilution permitting deferred autologous transfusion (apropos of 106 cases)]

To carry out normovolemic haemodilution in the best security conditions we elaborate a new method of preoperative haemodilution. Collection of red cell concentrates and adequate compensation are made either in the blood bank or at the patient's bed side. There are two ways of proceeding: *manual plasmapheresis technic is used for the collection of less than 450 ml packed red cells; *collection of more than 450 ml packed red cells is carried out on a PCS Haemonetics cell separator. CPD autologous red cells concentrates prepared in that way can be stored to meet the patient's need during and after the operation. The patient is identified as donor and receiver as regards laboratory analysis and computer treatment as well. Information's transmission between blood bank hospital and clinics is secured with the same document. This method enables homologues transfusion save and completes autologous transfusion in 68% cases among 106 patients. It is to be noticed that none of the 98 haemodiluted patients suffered from thrombosis.

Thallium 201 muscle scintigraphy: application to the management of patients with arterial occlusive disease

Skull (S), thigh (T), and calf (C) scintigraphies were performed by using 2 mCi thallium 201 IV in 30 patients suffering from stages II, III, and IV arterial occlusive disease (Fontaine's classification). Two indexes were calculated: P = T/C-C/S (T/C and C/S were the absolute values of radioactivity ratios measured before medical treatment) and R = delta(C/S)-delta(T/C) (where delta expressed the relative variation of the ratios measured after treatment and compared with initial values). Angiography was performed on all patients prior to treatment, and the results were quantified as 1 in the case of obliteration and 0.5 in case of stenosis of major arterial axes. Clinical improvement was demonstrated by a 100% increase in walking distance for stage II disease, abolition of pain at rest for stage III disease, and reepithelialization of trophic lesions for stage IV disease. Paraclinical effectiveness was evaluated by measuring ankle systolic pressure (SP) and index (SI) before and after treatment. The correlation observed between the values of P and angiography results was p less than 0.025 (Student t-test). The mean of P (measured before treatment) was 1.75 for the improved patients and 0.56 for the others (p less than 0.005). After treatment, R was +58% for improved patients versus -13% in those in whom the treatment was inefficient (p less than 0.025). P expresses the microcirculatory effects of arterial lesions detected by angiography. It is a prognostic index: satisfactory proximal perfusion (high T/C), associated with lesions that are essentially peripheral (low C/S), predicting a positive effect of medical treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effects of hemodilution on the ventricular function of the coronary patient]

Ten patients (9 males and 1 female: mean age: 64.8 +/- 7 yr) were studied. They were all stabilized coronary heart disease patients free of cardiac failure who where to undergo normovolaemic haemodilution as medical treatment of lower limb arteritis. Ventricular function was assessed by a radioisotope method: myocardial perfusion (thallium-201 and dipyridamole scintillation scan) and left ventricular contraction by technetium-99m angiography. Blood volume was measured by iodine-131 marked albumin. The following parameters were also measured: plasma viscosity, blood viscosity at seven different speeds, red blood cell aggregation index and filtration index. These were all measured before and 24 h after normovolaemic haemodilution which was carried out with à 5% albumin solution. This haemodilution was well tolerated: 1,062 +/- 335 ml of blood were sampled, the same volume of albumin being transfused, thus reducing the mean haematocrit from 0.42 +/- 0.05 to 0.32 +/- 0.02 (p less than 0.01). Normovolaemia was respected. Blood viscosity was reduced, especially at low speeds and the red blood cell aggregation index was also reduced. Ventricular contraction did not vary. Moreover, the basal myocardial state as assessed by the thallium scintillation count was not modified by the haemodilution, even being improved in three cases. The dipyridamole perfusion (the equivalent of an effort test) gave no changes in seven patients, resolved the ischaemic signs in two patients and slightly increased ischaemia in one case.