Arteriovenous difference of blood ammonia in uremic patients under hemodialysis.
In this study the ammonia concentration was determined in arterial and venous blood samples pre- and posthemodialysis (HD) in 18 uremic patients and in 18 health subjects (controls). The mean values (+/- SD) of ammonia in the arterial blood of uremic patients pre-HD were 98.32 +/- 26.55; post-HD, 63.18 +/- 17.09; and in control group patients, 72.37 +/- 10.09 micrograms/dl. In venous blood they were pre-HD, 71.70 +/- 20.68; post-HD, 58.05 +/- 16.73; and in control patients, 74.46 +/- 12.0 micrograms/dl. According to our findings, the ammonia concentration in the arterial blood of uremic patients pre-HD exceeds the normal limits and is significantly higher (p < 0.001) than that post-HD and that of control patients. The ammonia contents of venous blood pre- and post-HD ranges were within normal values, but the post-HD range was significantly lower than the pre-HD range (p < 0.05) and the control range (p < 0.01). Comparison between ammonia levels from arterial and venous blood showed significant and positive arteriovenous differences pre-HD (p < 0.001), which disappeared post-HD and were not observed in the control patients. In conclusion, uremic patients under HD present pre-HD high levels of ammonia in arterial blood with a significantly positive arteriovenous difference. In contrast, the post-HD ammonia levels in arterial and venous blood are decreased, and the arteriovenous difference is not significant.
Department of Nephrology, Aretaieon University Hospital, Athens, Greece.
B
B
Agroyannis
H
H
Tzanatos
C
C
Fourtounas
I
I
Kopelias
S
S
Katsoudas
K
K
Chondros
D000641:Ammonia / Q000097:blood*; D001158:Arteries; D006801:Humans; D006435:Renal Dialysis; D014511:Uremia / Q000097:blood* / Q000628:therapy; D014680:Veins
D000641:Ammonia