Hello, thanks for posting on HCM. First of all if he is taking any medications for high BP, they need to be stopped or lower the dosage after consulting your nephrologist. If he is not taking any medications, then it sometimes happen that patient on dialysis is overdone with the procedure. There is a minimum weight for the person undergoing dialysis which is called as ‘dry weight’. It is that weight which is free of any extra fluid or very minimal fluid in body after which weight reduction is not advised or done. Dialysis procedure removes the excess water along with waste products from body. So, if the patient has not gained much weight in period between dialysis but loses more weight during dialysis then he loses out the volume of fluid in body which causes hypotension which is low BP. I will advise you to talk with your nephrologist to consider weight reduction during next dialysis and see whether BP picks up and also to find out the appropriate dry weight for the patient and to maintain at that weight and not to lose weight below it. Thank you