Randomization using 4 blocks, randomization criterion is performed using block random allocation with 4 blocks, in which all four possibilities A, A, B, B and A, B, B, B and A, B, A, B and B, A, B, A are written on four cards and four patients randomly get picked up in each groups . The ward manager takes the patients card out of the bag and the patients are divided into groups . For example, if the card is A, A, B, B the first and second patients are in the first group, and the third and fourth patients are in the second group, and also for the next four patients, a card is picked again.