The sieving coefficient and clearance of vasopressin during continuous renal replacement therapy in critically ill children.
OBJECTIVE
As vasopressin is a small peptide, its sieving coefficient (SC) and clearance (CL) during continuous renal replacement therapy may be intermediate to those for urea and β2 microglobulin (commonly used markers for small- and middle-molecular weight solutes, respectively).


METHODS
A prospective, minimal-risk study was undertaken of the SC and CL of vasopressin in critically ill children on the first day of continuous renal replacement therapy using AN69 membrane filters and prefilter replacement fluid. All prefilter plasma (vasopressin) samples were drawn from the arterial port after predilution.


RESULTS
Nine patients with fluid overload, renal failure, or both were recruited (median age, 14 years) during the first day of either continuous venovenous hemofiltration (n = 3) or hemodiafiltration (n = 6). Multiorgan dysfunction syndrome was present in 8 patients, and 3 were in shock (2 were receiving a vasopressin infusion). Median prefilter plasma (vasopressin) was 1.7 pg/mL, although data points were skewed: 5 patients had a low prefilter plasma (vasopressin) (<2 pg/mL), and 4 patients (including 2 receiving a continuous vasopressin infusion) had a prefilter plasma (vasopressin) between 4.2 and 56.4 pg/mL. All those with low prefilter plasma (vasopressin) had an effluent (vasopressin) less than the detection limit (0.6 pg/mL). The median SC was 1 in the 4 patients with a measurable effluent (vasopressin), and their median filter CL was 48 mL/min or 39 mL/(min 1.73 m(2)).


CONCLUSIONS
The SC and CL of vasopressin by continuous venovenous hemofiltration or hemodiafiltration in these critically ill children were similar to values for urea.
Baird
J Scott
JS
Columbia University, College of Physicians and Surgeons, Children's Hospital of New York-Presbyterian, New York, NY 10032, USA. jsb106@columbia.edu
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003422:Critical Care; D016638:Critical Illness; D017583:Hemodiafiltration; D006440:Hemofiltration; D006801:Humans; D007223:Infant; D008657:Metabolic Clearance Rate; D009102:Multiple Organ Failure / Q000097:blood / Q000628:therapy*; D011446:Prospective Studies; D017582:Renal Replacement Therapy; D012769:Shock / Q000097:blood / Q000628:therapy*; D014508:Urea / Q000097:blood; D014667:Vasopressins / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D055815:Young Adult; D001613:beta 2-Microglobulin / Q000097:blood
D001613:beta 2-Microglobulin; D014667:Vasopressins; D014508:Urea