title: Failure of CAVH to remove digoxin-Fab complex in piglets.
abstract: Digoxin toxicity may be associated with renal failure and an inability to excrete the digoxin-Fab (antibody fragment) complex used in detoxification. We are unaware of any previous reports regarding the removal of digoxin-Fab fragment complex by continuous arteriovenous hemofiltration. Continuous arteriovenous hemofiltration allows ultrafiltration of molecules less than 50,000 daltons. Because the digoxin-Fab fragment complex has a molecular weight of 45 - 50,000 daltons, we evaluated the efficiency of continuous arteriovenous hemofiltration in removing the digoxin-Fab fragment complex. Three piglets were given 100 mcg/kg digoxin IM, in divided doses. Animals were anesthetized and continuous arteriovenous hemofiltration was begun using a Diafilter 10 cartridge. A mean ultrafiltration rate of 3.6 +/- 0.4 ml/min was obtained. The system equilibrated for 30 minutes and initial serum and ultrafiltrate digoxin levels were obtained. Mean serum values were total 6.20 +/- 1.74 ng/ml and free 3.72 +/- 0.88 ng/ml. Digibind 40 mg IV was given and then samples of serum and ultrafiltrate were obtained at 30, 60 and 90 minutes for digoxin levels. Mean values were as follows: 30 min serum total 54.23 +/- 26.13 ng/ml and free 0.08 +/- 0.08 ng/ml; 60 min serum total 61.24 +/- 27.31 ng/ml and free 0.07 +/- 0.04 ng/ml; and 90 min serum total 67.63 +/- 26.78 ng/ml and free 0.10 +/- 0.10 ng/ml. Ultrafiltrate levels throughout the experiment were negligible (less than or equal to 0.04 ng/ml). Continuous arteriovenous hemofiltration appears to be ineffective in removing the digoxin-Fab fragment complex.
authors.affiliation: Department of Pediatrics, University of Utah/Primary Children's Medical Center, Salt Lake City.
authors.forename: E J
authors.initials: EJ
authors.lastname: Quaife
authors.forename: W
authors.initials: W
authors.lastname: Banner
authors.forename: D D
authors.initials: DD
authors.lastname: Vernon
authors.forename: D W
authors.initials: DW
authors.lastname: Christensen
mesh_terms: D000818:Animals; D005069:Evaluation Studies as Topic; D005454:Fluorescence Polarization; D006440:Hemofiltration; D007140:Immunoglobulin Fab Fragments / Q000378:metabolism* / Q000633:toxicity; D007273:Injections, Intramuscular; D013552:Swine
chemical_list: D007140:Immunoglobulin Fab Fragments; C050199:digoxin antibodies Fab fragments