This study is a prospective, randomized, non-blinded study. 1 group will be assigned the standard arm with use of heparinised saline (10U/ml) lock in between each catheter use. This is consistent with the standard procedure of PICC care in the investigators' centre. The second group will be assigned the intervention with use of 4% citrate lock (Dirinco Citra-Lock 4%) in between each catheter use.