The hemodynamic effect of calcium ion concentration in the infusate during predilution hemofiltration in chronic renal failure.
BACKGROUND
It is the prevailing view that convective dialysis techniques stabilize blood pressure. Calcium concentration in the substitution fluid may be important in this respect. The aim of this study is to investigate the influence of calcium ion concentration in the substitution fluid on hemodynamic stability during predilution hemofiltration (HF).


METHODS
We conducted a randomized, crossover, blinded, controlled trial with 12 stable long-term hemodialysis patients without diabetes. Each patient was randomly assigned to substitution fluid with a calcium ion (iCa) concentration of 2.5 mEq/L (1.25 mmol/L; low-calcium session [L-HF]) or 3.5 mEq/L (1.75 mmol/L; high-calcium session [H-HF]) during 4.5 hours of predilution HF with a volume of 1.24 +/- 0.09 L/kg dry body weight and a temperature of 37 degrees C. Ultrafiltration was kept constant in each patient. Blood pressure (mean, systolic [SBP], and diastolic blood pressure [DBP]), pulse rate, arterial and venous temperature, energy transfer, and relative blood volume were measured at 15-minute intervals. Cardiac output, total peripheral resistance, stroke volume, and iCa were measured hourly. The 2 treatments were matched with the exception of iCa concentration.


RESULTS
A significant intratreatment reduction in cardiac output and stroke volume was shown to the same extent for both groups. Intertreatment comparisons showed a significantly lower mean arterial pressure, SBP, DBP, and total peripheral resistance in the L-HF compared with the H-HF group.


CONCLUSIONS
iCa concentration of 3.5 versus 2.5. mEq/L (1.75 versus 1.25 mmol/L) in the infusate during predilution HF stabilized blood pressure, possibly because of greater peripheral resistance rather than through changes in cardiac performance.
Karamperis
Nikolaos
N
Department of Renal Medicine C, Skejby, Aarhus University Hospital, Aarhus, Denmark. karamperis@stofanet.dk
Sloth
Erik
E
Jensen
Jens Dam
JD
D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D001810:Blood Volume; D001831:Body Temperature / Q000187:drug effects; D002118:Calcium / Q000008:administration & dosage / Q000494:pharmacology*; D002302:Cardiac Output / Q000187:drug effects; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006440:Hemofiltration; D006801:Humans; D007676:Kidney Failure, Chronic / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D016037:Single-Blind Method; D012996:Solutions / Q000008:administration & dosage / Q000494:pharmacology; D013318:Stroke Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
D012996:Solutions; D002118:Calcium