Technology: What Was

Preamble

A ‘new technologies’ chapter is quite difficult to write.

It mixes hope with expectation (yours) as it tries to temper (your) urgency with measured progress (ours) and, sometimes, a seeming lack of progress (also ours) … creating a sense of frustration for all.

There is no doubt that developments in the dialysis equipment world have been agonizingly slow. Indeed, no significant change occurred for over ¼ of a century – then, even after that, there has been precious little to show for an awful lot of ‘promising’ …

But … stuff is now happening.

The following chapter will try to introduce some of the closer, more likely, more imminent changes.

But … while rumour and hype are rife about implantable artificial kidneys, wearable artificial kidneys, and genetically engineered, stem cell grown kidneys, to be honest with you, these developments are far too far in the future – if attainable at all – to be covered here.

I am going to confine myself to those we know are here … or ‘about to be’ here … and ‘about’ means within the next 1-2 years.

While not all can be covered, the major developments are.

Some are clouded by ‘commercial in confidence’ agreements and, as such, only sketchy outlines can be given.

First, though, as understanding history permits a better grasp of the present, and the potential future, a brief look back into technology history.

In the beginning …

	The 50s saw Drake Willock pioneer the first proportioning dialysis system – a system which took a small sample of a concentrated solution of chemicals ‘the concentrate’, and mixed it with a larger sample of water to produce the dilution required to form the dialysis fluid – later (erroneously) to be called ‘the dialysate’. The first single pass dialysis system was the result.
	The 1960s saw the gradual introduction of chronic maintenance dialysis as an effective sustainable therapy for ESKD
	By the late 1960s, home haemodialysis had become the dominant option
	And … single pass proportioning dialysis systems were in use, as the dominant system, just as they are today

But …

One almost forgotten but key historical footnote …

In the 1960s-70s, NASA was seeking to reduce the water burden of manned space travel. Their goal was to develop a ‘sorbent’ system* that would …

o Recycle and purify rocket waste water

and …

o Make the urine of the astronauts fit to re-use for drinking

* NB: a sorbent is a substance which absorbs (or, more correctly, ‘adsorbs’) a range of substances that are contained within a solution. The sorbent, in a way, attracts then hangs onto the passing wastes and salts, removing them from solution. An analogy (though it doesn't really work like this) would be how a magnet attracts and holds ... a perfect sorbent would 'attract and hold' (or adsorb) all or any passing substance(s), be they salts, particulate matter, wastes … you name it … that are contained in the dialysis fluid as it leaves the artificial kidney. This would then result in their removal from the solution, leaving the solution substance-free.

The result of this work was a sorbent-based system that reconstituted ultra-pure water from waste water!

o For example, urine could be passed through the sorbent system and emerge at the other end as pure water!

Reynolds first applied this concept to dialysis technology and used a staged sorbent column to regenerate dialysis fluid

– The sorbent column was built of layered ‘sorbents’ – each capable of adsorbing different substances from the dialysate … in series: activated charcoal, zirconium phosphate, urease, and lastly zirconium oxide and zirconium sulphate.

– The end result ? … the ‘dirty’ dialysis fluid was cleaned of all its contained impurities, salts and other substances. Pure water resulted, suitable for re-forming with a chemical concentrate back into fresh dialysate for re-presentation to the dialyzer.

The ‘Redy™’ dialysis system (Redy = Regeneration of dialysate) was the result.

Many of the older dialysis nurses and docs (like myself) will remember this system with some fondness … it was highly portable and used only 6 litres of water per treatment – a true ‘have machine, will travel’ system!

The sorbent column would just kept on adsorbing and adsorbing … cleaning the used dialysate to water … reforming it … passing it back to the dialyser to remove more waste from the patients blood … then … back through the column … leaving all waste in the column … and so on … round and round and round … for the duration of the treatment.

Neat!

The Redy was actually a ‘ripper’ machine

– As they say on late night TV, it pretty much … ‘diced, as it sliced, as it cleaned’

– It was ‘ultimately portable’

– It used only 6 litres of water

– It continuously regenerated fresh dialysis fluid from used dialysate

– It was largely responsible for the popularity (and sustained use) of home HD in Australia and New Zealand

The fate of the Redy …

	As dialysis became more available
	As facility care – especially local, suburban, point-of-delivery dialysis care (in ANZ = ‘satellite dialysis’) developed and expanded
	As parallel plate dialysers (1970s) translated to hollow fibre artificial kidneys (HFAK) in the 1980s
	As the HFAK costs then rapidly fell via economies of scale
	As interest in home (and portable) HD gave way to facility care with centralised water treatment systems

… the (relatively) costly Redy sorbent cartridges couldn’t compete

… eventually, the Redy ‘died’ a sad, lonely, nearly forgotten death

And … we entered the unchallenged period (1990 onwards) of the single pass dialysis system - as we currently know it

The sequential history …

· A few brave ventures – some doomed to failure, some ultimately successful – then followed. A number of small, focused research companies in the US soon began to shift the paradigm …

1. Aksys was founded … 1991

2. NxStage was founded … 1998

3. Renal Solutions was founded … 2000

4. Aksys was approved for home HD … 2002

5. NxStage approved for HD … 2003

6. Fresenius introduced the ‘K@Home’ … 2004

7. Renal Solutions Allient approved for HD … 2005

8. NxStage approved for home HD … 2005

· Then … in 2007 … Aksys went to the wall – the company failed, the machine disappeared, and its patents were ‘shelved’.

· Then …

9. Aksys patents were purchased by Deka … 2007

10. Baxter acquired Aksys patents … 2007

11. Fresenius bought Renal Solutions … 2007

12. Fresenius bought Xcorporeal intellectual rights … 2009

13. NxStage ‘off-shored’ beyond the US. … 2009/10

So …

... the Aksys

... the NxStage

... the Allient

... the Xcorporeal

... the Fresenius PAK

... the Quanta

... the AWAK

What are (or were) these systems ?

… oh, and there are other emerging machines and systems, too!

The Aksys PHP system …

Though no longer available, new thought, the dawn of progress, the daring to think differently, really began with this machine!

The Aksys appeared in the mid 1990s – a bold new system that took some of the long-held principles of single pass dialysis and turned them on their ear.

At the heart of the Aksys system was the concept of reuse of the entire dialysate and blood line system – along with reuse of the dialyser – the whole disposable circuit of ‘consumables’ being changed but once a month instead of at each dialysis.

At the end of dialysis, the arterial and venous lines were simply disconnected from the access, plugged into the machine, then a button pushed that said ‘sterilize’.

The whole system would then undergo hot water sterilization such that some 16 hours later, the system was ready to ‘go again’!

At the start of the next dialysis, the arterial and venous lines were simply unplugged from the machine and reconnected to the access and a button pushed that said ‘go’.

Connection and disconnection were down to a 5 minute process. The machine self cleaned its’ lines and dialyser. Once a month, the lines and dialyser were replaced. The system self-manufactured its’ own ultra-pure dialysate in a 60 litre tank.

While the Aksys ‘died’ a sad financial death in 2006, its patents lived on – on a shelf at Deka in New Hampshire – till Baxter partnered Deka in late 2007 and gained access to the Aksys patents.

The importance of this story is to understand where Baxter will be taking us with their new Home Dialysis System – currently negotiating the labyrinthine processes of the FDA.

But more of this later …