AN-69 membrane reactions are pH-dependent and preventable

We report two pediatric patients who required blood priming for continuous venovenous hemodiafiltration. Both of these patients developed a significan t hypotensive episode with initiation of continuous venovenous hemodiafiltr ation with immediate resolution on discontinuation. The most notable common characteristics of these patients were the use of the Multi-flo 60 (AN-69) dialyzer membrane and blood priming. No similar episodes were encountered when patients were primed with saline or albumin. The AN-69 membrane is exq uisitely pH sensitive, The lower the pH concentration of the blood passing by the membrane, the greater the activation of bradykinin, a known hypotens ive-inducing agent, by the dialyzer, On review of blood available from our blood bank, the following parameters became apparent. The pH of standard bl ood available from our blood bank ranged from 6.1 to 6,4, The blood obtaine d from our blood bank had significant hyperkalemia, hyponatremia, and hypoc alcemia. No reactions were noted when patients were primed with normal sali ne, which has a pH of around 5,9, We speculate that the presence of endogen ous blood substances, such as bradykinin, may have induced the hypotensive episodes. We describe two techniques we developed that should allow for the increased safe and effective use of the AN-69 membranes in continuous veno venous hemodiafiltration circuits. These observations indicate the requirem ent for careful and close attention to detail when delivering renal replace ment therapy to anyone, but especially patients weighing less than 10 kg. ( C) 2001 by the National Kidney Foundation, Inc.