2.3 Patient grouping and randomization
Patients undergoing modified radical mastectomy were randomly divided
into three groups. The patients were randomly allocated into three
groups based on a computerized randomization table created by a
researcher who was not involved in the study. The researchers randomly
assigned an ID card to each registered patient, each of which was sealed
in an opaque envelope3. The nerve block technique was
performed by another anesthesiologist who was completely unaware of the
patient’s ID. None of the patients knew the specific grouping. a blind
anesthesiologist(AIU), used the patient’s ID, to collect data In the
breast surgery ward. Surgeons, attending anesthesiologists, outcome
evaluators and data analysts do not know the specific grouping.