GELATIN USE IMPAIRS PLATELET-ADHESION DURING CARDIAC-SURGERY

Artificial colloids based on gelatin are used as plasma expander to re place donor blood products. In laboratory experiments, gelatin reduced both the velocity and extend of platelet agglutination by ristocetin, and only the agglutination velocity by polybrene (p <0.05). Furthermo re, gelatin delayed the in-vitro platelet plug formation under shear-s tress in the absence of ADP (p <0.05), whereas gelatin induced no dela y in the presence of ADP, Thus, after induction of vWF release from pl atelets by polybrene or ADP, platelet function was normal. These resul ts indicate that gelatin affects in particular the functionality of pl asma-vWF and partly inhibits platelet adhesion. These negative effects of gelatin on hemostasis were demonstrated in two clinical studies du ring cardiac surgery. In a randomized study of sixty patients undergoi ng cardiac surgery, gelatin as prime in the heart-lung machine appeare d to result in diminished efficacy of aprotinin on hemostasis, whereas it did not affect hemostasis in non-aprotinin patients. An additional retrospective clinical study showed that only high dose of gelatin af fected hemostasis. This suggests a limited role of plasma-vWF and a st rong back-up mechanism of platelet-vWF in achieving hemostasis.