Nurse Wally knows that the most important aspect of the preoperative care for a child with Wilms’ tumor would be:

Checking the size of the child’s liver Monitoring the child’s blood pressureMaintaining the child in a prone positionCollecting the child’s urine for culture and sensitivity

Explanation.

Because the tumor is of renal origin, the rennin angiotensin mechanism can be involved, and blood pressure monitoring is important.