Yeah the patient was in a coma. When someone is on a bed laying in one position for too long, their body can develop sores. So nurses or caretakers usually shift the person from one side to the other every day to make sure they aren't sleeping in the same position for more than a few hours. Bed sores are very nasty and painful for bed ridden patients.

Since Jessica Chastain's character has myocardial issues (heart problems) - lifting and shifting another person from one side to the other is tough and dangerous. The person's weight can pull on the nurse's heart muscles and cause stress.