Final answer:
A rise in Transmembrane Pressure (TMP) during hemodialysis likely indicates excessive sodium reabsorption by renal tubes due to a reduction in water reabsorption in the kidneys.
Step-by-step explanation:
A rise in Transmembrane Pressure (TMP) during hemodialysis likely indicates excessive sodium reabsorption by renal tubes due to a reduction in water reabsorption in the kidneys. During hemodialysis, the patient's blood is passed through a semipermeable membrane in the dialysis machine, which has a higher solute concentration compared to the blood. This creates a higher pressure on the blood side, causing excess sodium to be reabsorbed by the renal tubes and reducing water reabsorption. This rise in TMP can lead to imbalances in solute and water levels in the body.