Continuous veno-venous hemofiltration with regional citrate anticoagulation: a four-year single-center experience.
BACKGROUND
Hemofiltration protocols using a citrate-buffered replacement solution offer the advantage of regional anticoagulation and a buffer effect. The role played by such fluids in clinical practice is not yet well established. The risk of electrolytic disorders, acid-base imbalance, or citrate accumulation should be clarified. We report on a renal therapy protocol based on a citrate isonatremic replacement solution.


METHODS
We considered all patients needing renal replacement therapy admitted to our cardiovascular intensive care unit between January 2003 and June 2007. A citrate-buffered fluid was delivered in predilution mode to a post-filter ionized calcium target < or = 0.25 mmol/L. Extracorporeal blood flow was set at a constant of 140+/-10 ml/min. Blood calcemia was maintained by a 5% calcium-chloride solution infused into the patient. We recorded the patients' acid-base variables, ionized calcium, daily electrolytes, albumin, urea and filter life-span.


RESULTS
We observed 101 consecutive patients out of 2,523; incidence 4%, overall mortality was 57% at ICU discharge. Mean replacement rate was 2,554+/-475 ml/h corresponding to 34+/-5 ml/kg/h. Mean patient ionized calcium level was 1.07+/-0.04 mmo/L, maintained by 13+/-2 ml/h of infused calcium-chloride. All other electrolytes remained in the normal range. The Stewart biophysical approach confirmed a strong anion gap of 3.1+/- 3 meq/L. Acid-base balance showed a buffer effect. Mean filter life-span was 52+/-11 h.


CONCLUSIONS
Renal replacement therapy based on citrate-buffered fluid may be useful in clinical practice. This methodology presented an adequate metabolic control and allowed regional anticoagulation. A sufficient calcium supply was mandatory to avoid hypocalcemia. The small strong ion gap suggested a modest citrate accumulation.
Cassina
T
T
Anesthesia/Intensive Care Unit, Department of Cardiac Anesthesia, Cardiocentro Ticino, Lugano - Switzerland. tiziano.cassina@cardiocentro.org
Mauri
R
R
Engeler
A
A
Giannini
O
O
D000136:Acid-Base Equilibrium / Q000187:drug effects*; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D015415:Biomarkers / Q000097:blood; D001777:Blood Coagulation / Q000187:drug effects*; D002021:Buffers; D002118:Calcium / Q000097:blood; D002122:Calcium Chloride / Q000008:administration & dosage; D019343:Citric Acid / Q000008:administration & dosage* / Q000009:adverse effects; D015314:Dialysis Solutions / Q000008:administration & dosage* / Q000009:adverse effects; D006440:Hemofiltration / Q000295:instrumentation; D006801:Humans; D007552:Isotonic Solutions; D008567:Membranes, Artificial; D008875:Middle Aged; D012709:Serum Albumin / Q000378:metabolism; D013997:Time Factors; D016896:Treatment Outcome; D014508:Urea / Q000097:blood
D000925:Anticoagulants; D015415:Biomarkers; D002021:Buffers; D015314:Dialysis Solutions; D007552:Isotonic Solutions; D008567:Membranes, Artificial; D012709:Serum Albumin; D019343:Citric Acid; D014508:Urea; D002122:Calcium Chloride; D002118:Calcium