The answer I will give is far more complex than you might have thought, but I will try to keep it as simple as I can.
You say you have ‘reached your dry weight’ and though I note your reasoning for that is ‘a hoarse voice from dehydration’, and that your ‘blood pressure is still high.’ Although these are both clearly troubling for you, I am not sure that they necessarily mean what you think they do - or at least, are not the whole story. Can I suggest you also consider some of the following points - all of which have been proffered without any knowledge of other key variables like: age, gender, body weight and habitus, medication, co-existing disease (diabetes, cardiac disease etc.), and other past history - as all or any of these may temper/change the responses I give below. That said, here goes:
Firstly, and importantly, you do not say whether you are on any anti-hypertensive medication … for if you are, then by definition – dry mouth or otherwise – you re not at dry weight. There are other reasons why your mouth may be dry … specifically, the rate of volume removal during dialysis.
We have all learned much from Bernard Charra and Charles Chazot in Tassin (near Lyon in France) whose experience in volume management in HD since the 1970’s has shown that one can only be at dry weight if all anti-HT medications have been ceased and the blood pressure has normalised (pre and post dialysis) with pre-BPs in the 135-140/- range and post BPs in the 120/- range. To achieve this also requires long, slow volume removal – in their program: 8 hours x 3-4 x week.
If you are on (or require) BP medication(s), then you are not at dry weight – even if you might think you are. Further, if you are on BP meds (hopefully not), then are you withholding them prior to dialysis? If you are not, then this is something to discuss with you team … though also if you are, I would argue this is also something to discuss with your team.
You do not give your body weight, nor your inter-dialytic weight gains … but these measurements matter, as a 4 hour treatment – even if you think this should be long enough – may still be removing fluid at a (xxx) ml/kg/hr rate sufficient to dry out your mucous membranes (your dry mouth and your sensation of an altered voice) yet fail to control your BP – or even cause your BP to rise (yes, rise) through dialysis such that your exit BP is greater than your entry BP. This latter phenomenon is often called ‘paradoxical’ intra-dialytic hypertension. This phenomenon is symptomatic of chronic fluid overload (yes, overload) … and is present in +/- 15% or so of all dialysis patients, despite that they (and their professionals) believe them to be at ‘dry’ weight. Can I suggest that you copy and enter the following URL into your browser: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4854275/ … then read the first 18 words of the ‘Summary’ paragraph. The rest gets a bit hairy, but that will give you a sense of where the rest leads to.
Can you also read my ‘primer’ on dialysis weight at the KidneyViews site … see: http://www.homedialysis.org/news-and-research/blog/201-A-Primer-on-Haemodialysis-"Weight"
= one of my 75 or so blogs about better dialysis at KidneyViews … it will help you (I hope) to better understand weight on dialysis.
Importantly, it seems that you have switched from a system (the Fresenius 2008K) that permits the dialysate sodium to be easily varied, to one that does not. You do not say what the Fresenius sodium setting was set at, back in your better (if I might say so) period of 8 years of (I presume BP-stable) nocturnal home HD on the Fresenius 2008K, but I wonder if it was in the 137-138 range = a common setting range and a range we often use. A key difference is that the dialysate sodium in the Pure Flow created dialysate is set (and unalterably so) at 140, as best as I know … see https://www.nxstage.com/wp-content/uploads/2017/08/NxStage-Therapy-Handbook-APM907.pdf (scroll to page 39 for dialysate fluid compositions). The Pure flow sodium concentration is fixed and cannot be individualised or adjusted - again to the best of my understanding.
The dialysate sodium is (or can be) a critical component in BP, volume and dry weight management … and I would venture to say that the 140 delivered by the Pure Flow might be a tad high for you. Another uncertainty is whether the Pure Flow sodium is actually 140 … as dialysate sodium concentrations can sometimes be more then we bargain for! We often run sodium concentrations of 137 or 138 – we vary them from patient to patient as it seems fit – in order to encourage sodium efflux and fine-tune volume management. Unfortunately, the NxStage system does not permit individually variable dialysate constructs – at least for sodium – one of its several Achilles heels. It might be interesting for your team to sample the dialysate your Pure Flow is creating for you and determine if the actual sodium concentration is the 140 that it is said to be.
As one who has spent a long professional lifetime arguing for the benefits of longer, slower, gentler, more physiological haemodialysis, it is something of a mystery to me why you would chose (or have had ‘chosen’ for you) to switch from a single pass system in the ‘longer, slower, gentler, more physiological’ setting (with, perhaps, a lower sodium setting on the machine), to a short hour, un-adjustable sodium system. But … I won’t go there.
It would be of passing interest to see what your ml/kg/hr calculations were (doing several serials) using the UFR calculator I devised with the help of our team, here, in Geelong for the Home Dialysis Central site and that has been available (and widely used) since early 2017. You can find this at https://www.homedialysis.org/ufr-calculator … You may find this useful and, if your clinic is not using it, I hope I might be forgiven for asking why not?
If (1) you do plug your numbers in and (2) if you do find you are in excess of 8ml/kg/hr = our current recommended maximum, then there are several steps you can take to ‘get there’.
… wean from all anti-HT drugs, preferably following the Tassin Guidelines
… to achieve a target UFR <8ml/kg/hr, these are the three key imperatives:
Drink less fluid in the inter-dialytic period (easier said than done)
Control and strictly diminish your inter-dialytic sodium intake
Lengthen your dialysis sessions such that the UFR is reduced to <8ml/kg/hr (max.)
There are many more nuances that I could pack this answer with, but these key points do give you a starting point.
But … discuss all these points with your team.
Remember: any advice over the Internet is given (despite with all good intention) without ‘knowing’ you, as an individual … and your team does
Internet advice is given without knowledge of your individual history’
… what is your age, weight, height, gender (none have been given)
… are you diabetic – that changes stuff
… do you have cardiac disease – that changes stuff, too
Hopefully, though, this will give you some threads to follow up with your team.