“…In the case of heparin there is no demonstrated relationship between degree of heparinisation, as measured by the activated partial thromboplastin time (APTT) and duration of circuits [1]. We have shown that, in a small group of CIPs receiving CRRT, there was no significant relation between the starting, mean, highest and lowest APTT and circuit life [10]. Furthermore, there appears to be no reliable way to predict which CIP needs heparin at all.…”