AbstractIn the light of evidence which linked heparin induced thrombocytopenia (HIT) to the prolonged flushing of intermittent IV cannula with heparinised saline, a randomised control trial was mounted to determine whether this solution was a superior flushing agent to normal saline. 152 inpatients between the ages of 2 months and 18 years were allocated to a control group which had heparinised saline prescribed as a flushing agent, or an experimental group which was prescribed normal saline. Each day IV sites were examined for signs of phlebitis and on removal each cannula was flushed to check for fibrin. In total 200 cannulae representing 510 IV days were assessed. No significant differences were detected in either the duration of IV therapy, the patency of the IV line or the incidence of phlebitis when normal saline was used to flush the IV cannulae. On chi square testing however, highly significant associations emerged between the incidence of phlebitis and the use of the IV antibiotics tobramycin (p=0.05) and/or Timentin (p=0.008). In addition, young children were found to have a significantly higher incidence of blocked cannulae—regardless of the flushing solution used.