[Urea and ammonia metabolism as partial aspects of nitrogen metabolism after surgery using the heart-lung machine].
22 patients undergoing open heart surgery for mitral valve dysfunction using extracorporeal circulation were studied pre- and postoperatively. Our study revealed a hypercatabolic situation with increased excretion of total nitrogen, urea and less significant excretion of ammonia on the day of surgery and during the 1-4th postoperative days. The portion of urea in percent of the total nitrogen excretion rose up to 95%. Ammonia excretion, however, did not exceed 4% during the whole period of investigation (7 days preoperatively, the day of surgery and 13 days postoperatively). Obviously the combined enteral and parenteral nutrition containing an average of 59.5 g protein, 207.0 g carbohydrate and 47.8 g fat per day which gave a total caloric intake of 1,536 kcal/day was not sufficient to compensate for the postoperative catabolism, but excessive situations could be avoided. The values of urea and nitrogen excretion in relation to the nitrogen intake indicate that a sudden shift of enteral and parenteral nutrition is associated with a considerable loss of body nitrogen. Therefore we suggest simultaneous enteral and parenteral nutrition which should be shifted only gradually over a period of 10-12 days to complete enteral nutrition for the postoperative treatment of patients undergoing open heart surgery with the use of extracorporeal circulation.
D000328:Adult; D000641:Ammonia / Q000378:metabolism; D005112:Extracorporeal Circulation; D005260:Female; D006801:Humans; D008099:Liver / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009584:Nitrogen / Q000378:metabolism*; D010288:Parenteral Nutrition; D014508:Urea / Q000096:biosynthesis / Q000378:metabolism*
D000641:Ammonia; D014508:Urea; D009584:Nitrogen
Harnstoff- und Ammoniakstoffwechsel als Teilaspekte des Stickstoffmetabolismus nach Operationen mit der Herz-Lungen-Maschine.