My Dad has been eating dinner late - last night it was after ten pm. Could that be why his UF has been low?
Is his UF low on his initial drain or on his total UF overnight? The most common reasons I’ve heard as a social worker for low UF in PD is constipation, patient positioning, the height of the machine in relation to the patient, location of the catheter tip. I’ve not heard of mealtime as a reason for low UF, but that would be a question to ask the home training nurse or nephrologist.
Has your father’s clinic recently performed a peritoneal equilibration test to determine how your father’s peritoneal membrane transports wastes and fluids. Some patients do well on the cycler (APD or CCPD) overnight while other patients do better with manual (CAPD) exchanges during the day. Here’s a description of the PET which helps to determine what type of dialysis a patient should do. Clinics are supposed to do these tests every 4 months.