The acid-base effect of changing citrate solution for regional anticoagulation during continuous veno-venous hemofiltration.
OBJECTIVE
To compare the acid-base balance effects of two different citrate doses for regional citrate anticoagulant (RCA) for continuous veno-venous hemofiltration (CVVH).


METHODS
We used a commercial citrate fluid (citrate concentration: 11 mmol/L) from July 2003 to July 2004 (period A) in 22 patients; then changed to a new citrate fluid (citrate concentration: 14 mmol/L) from July 2004 to Feb 2005 (Period B) in 21 patients. Replacement fluid rate was fixed at 2,000 ml/h. We measured all relevant variables for acid-base analysis according to the Stewart-Figge methodology.


RESULTS
After commencement of RCA-CVVH, there was a change in bicarbonate and base excess (BE) toward acidosis for both fluids. This change was significantly different between period A and B at 6 and 12 hours (pH: p<0.01, BE: p<0.05) with greater decreases with the 11 mmol/L citrate fluid. These changes were mostly secondary to an increase in the strong ion difference (SID) and occurred despite an increased strong ion gap (SIG) (+0.5 mEq/L vs. +1.5 mEq/L; p<0.01) in the higher citrate concentration fluid. Cessation of RCA-CVVH was associated with short-lived differences in bicarbonate and SIG which were similar to those seen on initiation of RCA-CVVH but in the opposite direction.


CONCLUSIONS
A small increase This was partly offset by an increase in SIG, consistent with increased citratemia. Cessation of treatment showed a differential improvement in SIG also consistent with disposal of therapy-associated citrate. These observations might assist clinicians in interpreting acidbase changes during RCA-CVVH.in citrate infusion rate caused an alkalinizing increase in SID.
Egi
M
M
Department of Intensive Care, University of Melbourne, Austin Hospital, Austin Health, Melbourne, Australia.
Naka
T
T
Bellomo
R
R
Langenberg
C C
CC
Li
W
W
Fealy
N
N
Baldwin
I
I
D000136:Acid-Base Equilibrium / Q000502:physiology*; D058186:Acute Kidney Injury / Q000628:therapy; D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D019343:Citric Acid / Q000008:administration & dosage*; D016638:Critical Illness; D005260:Female; D015312:Hemodialysis Solutions / Q000008:administration & dosage*; D006440:Hemofiltration / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged
D000925:Anticoagulants; D015312:Hemodialysis Solutions; D019343:Citric Acid