Interaction of renal prostaglandins with the renin-angiotensin and renal adrenergic nervous systems in healthy subjects during dietary changes in sodium intake.

In six healthy subjects the role of renal prostaglandins (PG) in modulating the actions of the renin-angiotensin and renal adrenergic nervous systems on renal function was investigated. During high dietary sodium intake (350 mmol/day) for 4 days no changes in urinary excretion of PGE2, PGF2 alpha, noradrenaline or adrenaline were noted, whereas plasma renin activity (PRA) and urinary aldosterone excretion were suppressed. After 4 days of low sodium intake (35 mmol/day) urinary excretion of PGE2, aldosterone and noradrenaline, as well as PRA, had significantly increased. Inhibition of PG synthesis with indomethacin (2 mg/kg body weight) had no effects on renal function on day 5 of high sodium intake. Despite suppression of PRA and urinary aldosterone, indomethacin significantly reduced p-aminohippurate (PAH) clearance, glomerular filtration rate (GFR) and urinary sodium excretion on day 5 of low sodium intake, when urinary noradrenaline excretion remained high. The results point to the crucial role of the renal adrenergic nervous system in controlling renal vascular resistance and sodium conservation in healthy subjects during low sodium intake, which is unmasked when renal PG synthesis is blocked by indomethacin. Enhanced renal PG synthesis during sodium restriction therefore not only attenuates the vascular and tubular effects of the renin-angiotensin system but, more importantly, also those of the highly stimulated renal adrenergic nervous system.

[Intraoperative autotransfusion in extensive orthopedic interventions]. / Intraoperative Autotransfusion bei grossen orthopädischen Eingriffen.

In large orthopaedic operations massive blood losses sometimes can hardly be avoided. Apart from other autotransfusion methods (repeated preoperative withdrawal of blood or isovolaemic haemodilution) the intraoperative autotransfusion (IAT) has proved particularly useful. By means of the autotransfusion system Haemonetics Cell Saver, whose functional performance is described in the following, there was a decrease in homologous erythrocytes of 60.5 l, that is more than 300 erythrocyte concentrates. With regard to the intraoperative period the average reduction in donor blood for each patient was between 68.0 and 94.8%. Considering the compensation of postoperative blood losses there was a decrease in donor blood of between 55.6 and 66.2%. The importance of this reduction in donor blood (decreased hepatitis risk and better quality of the autologous erythrocytes) is discussed. On close and critical examination of advantages and disadvantages concerning the intraoperative autotransfusion, we have to give the preference to the Haemonetics Cell Saver, especially in the orthopaedic range.

[Heparin elimination in intraoperative autotransfusion with the haemonetics cell saver]. / Heparin-Elimination bei intraoperativer Autotransfusion mit dem Haemonetics Cell Saver.

Intraoperative autotransfusion has proved useful in decreasing decisively the need of donor blood in major operations. Due to an important technical development of the equipment used including the possibility to separate red blood cells and to wash them in physiological saline, typical problems occurring during intraoperative autotransfusion seem to be overcome for the most part. One of these problems is the retransfusion of the citrate or heparin added for anticoagulation of blood. Heparin itself may be responsible for a disturbance of coagulation. The efficiency of eliminating heparin by washing it in the Haemonetics Cell Saver was tested by means of a high sensitive heparin test. Partly the samples were totally free of heparin, partly small remains of heparin could be found. Even the maximum value of 60 I.E. measured in one autologous red blood cell concentrate is of no importance for the daily clinical practice. Intraoperative autotransfusion with the Haemonetics Cell Saver is also superior to a homologous transfusion of blood with its unavoidable share of citrate.