[Hypervolemic hemodilution in surgical blood loss]

Two quantitative variants of the procedure recommended for use in accordance with the volume of blood loss were developed on the basis of results of the employment of hypervolemic hemodilution in surgical blood loss in 433 patients. Clinico-physiological analysis showed hypervolemic hemodilution to be responsible for optimization of hemodynamic regimen under conditions of surgical blood loss at the expense of stimulation of heterometrical mechanism of control of the minute volume of blood circulation.

Moderate and extreme haemodilution in open-heart surgery: electrolytes, urea, creatinine and osmolality

Two different programs of treatment, called moderate and extreme haemodilution, respectively, have been compared in patients undergoing aortic valve replacement. Serum electrolytes, urea, creatinine and osmolatity were satisfactory in both groups during and after surgery. A substantial retention of sodium took place in the moderately diluted patients. The extreme group lost more potassium in the urine than the moderate one. A small post-operative rise in creatinine indicates a slight kidney damage in the moderate group. Increased serum urea following moderate dilution might partly be due to increased protein catabolism.

Moderate and extreme haemodilution in open-heart surgery: evaluation of haemolysis, cell damage and protein changes

Clinical chemical data from patients operated upon in moderate and extreme haemodilution have been compared. Haemolysis was more pronounced during and after moderate dilution that in extreme dilution. A slight liver damage was found post-operatively after moderate dilution. Several changes were of about the same magnitude in both groups: Serum CK increased, reaching maximal activity 3-18 h after operation. An acute phase reaction of plasma proteins took place post-operatively, except that the concentration of complement C-3 dropped during the first days after operation. The serum levels of phosphate were positively correlated to several of the acute phase proteins.

[Hemodilution--methodological problems]

To achieve normovolemic hemodilution two methods have established themselves: the acute preoperative hemodilution and the therapy with different blood constituents. The ever increasing consumption of blood and blood products shows the absolute necessity of using all the available constituents, especially the erythrocytes. A proved and standardized transfusion program is shown, which --allows blood substitution with specific hemodilution without additional expenses of time and organization or technical difficulties, --shows means of substituting 80% of the blood consumption with packed red cells (Erythrozytenkonzentrate), --helps save blood and blood products, --unites the plasma production with that of the erythrocytes.

Hemodilution causes decreased compliance in puppies

Cardiopulmonary bypass and hemodilution in the newborn have been associated with increased myocardial edema, which may be due to immature connective tissue formation. Five adult and four puppy dogs were placed on bypass while compliance and ventricular function (intraventricular balloon) were measured during normohemoconcentration (NH) (hematocrit 45.1, osmolality 307) and hemodilution with normal saline (hematocrit 24.7, osmolality 307). Compared with NH, the adult group showed no change in compliance or function after 90 min of hemodilution. The puppy group showed a marked decrease in compliance with hemodilution compared to NH (P < 0.001) without change in ventricular function when peak systolic pressure was plotted against end-diastolic volume. Electron micrographs confirmed greater edema formation in the puppy group than the adult group with hemodilution. These changes demonstrate that the newborn heart is more sensitive to edema formation than the adult during hemodilution and that filling pressures do not necessarily reflect ventricular performance during the early post-perfusion period when compliance is decreased.

Effect of haemodilution on experimental cerebral oedema in cats

The effect of haemodilution with Dextran 60 on experimental cerebral oedema produced by the modified method of Ishii, Hayner, Kelly & Evans (1959) is described. The intracranial pressure was measured from the cisterna magna or epidurally in the parieto-occipital region. In the group of cats subjected to haemodilution, with a haematocrit of 27.20 +/- 1.48%, the intracranial pressure first increased by 500% and, after 1.5 h, began to fall gradually so that at the end of the experiment it was only 160% of initial value. In the other experimental group in which haemodilution with a haematocrit of 27.40 +/- 1.14% was started after 6 h of the experiment, the intracranial pressure gradually fell for the next 6 h from 350% of initial value of 200% of initial value after 12 h. It was concluded that haemodilution slows down the development of cerebral oedema, and can be employed in the treatment of fully developed oedema.