Nick Hoenich describes the evolution and clinical application of haemodialysis technology up to 2005. The review is based on the technology used at Newcastle upon Tyne, but does not provide  a definitive timeline as  the adoption of technology within dialysis units differed and recollections vary.

Before the 1960s

Prior to 1960 the treatment of renal failure focused on the treatment of acute renal failure, almost entirely at teaching or major city hospitals where physicians had an interest in electrolyte management associated with renal failure. This included the Royal Air Force Renal Unit at Halton,  the Postgraduate Medical School at Hammersmith Hospital in London, Leeds General Infirmary, Glasgow, Edinburgh, Newcastle and Belfast.

At Leeds, the  treatments were performed using the Kolff Brigham kidney in which a tubular membrane was wrapped around a drum which rotated in a bath of dialysis fluid. Blood flowed through the tubular membrane by the “Archimedes screw principle” assisted by a pneumatic pulsatile pump which was sited in the return segment of the circuit to prevent excessive expansion of the tube containing the blood during use.   A split coupling connected the membrane to the extracorporeal circuit at the inlet and outlet. The coupling allowed a link to the circuit to be maintained as the drum rotated. The rotating drum assembly had a transparent Lucite hood to minimize heat losses during use.  There was no blood leak detection system, and the dialysis fluid was changed every two hours. Hammersmith used a French-manufactured Kolff Brigham type, made by Société Usifroid, (Paris.) (Figure 1).

Other units used a delivery system developed by Baxter Laboratories (Deerfield, Ill, USA) and which became available commercially  in October 1956. (Figure 2).

The delivery system was intended for use with the  disposable coil dialyser developed by Kolff in collaboration with Bruno Watschinger from Vienna at the Cleveland Clinic,  and manufactured by Baxter.

The dialyser consisted of a central core around which a woven fibreglass mesh was wound. Two tubular membranes (hence the term Twin coil) were sandwiched between adjacent layers of the support material.

The dialyser was seated in a a metal container, at the centre of a circular stainless steel tank containing 100 liters of dialysis fluid (Figure 3.)

 

Fig.3: Closeup of the coil in the stainless steel pot; Fig. 4: A Baxter Kolff system fitted with a Sarns Pump; Fig 5: Baxter Kolff system. Top view of the tank and coil pot assembly

A pump recirculated the dialysis fluid through the coil assembly during treatment. It was also used to empty the tank.  The dialysis fluid was changed every two hours and patients were dialysed using a weigh bed to provide an indication of changes in weight during treatment. In such systems initially a Sigmamotor finger pump (Sigmamotor Inc, Middleport, NY, USA) was used to facilitate the blood flow. By 1964 it was  replaced with the quieter  Sarns roller pump designed for paediatric cardiac surgery and adapted for haemodialysis use by Baxter Laboratories(Figures 4 & 5).

The preparation of the dialysis fluid was rudimentary,  and as the heater incorporated in the tank was intended to maintain the temperature rather than to heat it from room temperature, the water component of the dialysis fluid was added to the tank using a mixer tap.

Weighed amounts of electrolytes (sodium chloride, calcium acetate, potassium acetate, sodium bicarbonate, glucose and lactic acid) were then added. To ensure that the composition of the fluid was correct, a sample was sent to the laboratory, and treatment would begin once the results were reported.

In Sweden, Nils Alwall had been working on various designs for an artificial kidney, and in collaboration with Avesta Jernverk AB, a Swedish company specializing in the production of stainless steel, produced the Avesta dialyser in the early 1950s, The design which went through a number of iterations consisted  of two perforated stainless steel cylinders  . A cellophane tube, 20-21 m in length (dialysis surface of 1.6 m²) was wound on the smaller one and placed inside the larger cylinder. The assembly was placed into an outer solid cylinder which contained the dialysis fluid, with a heater. The dialysis fluid (120-140L) was hand mixed and needed to be changed during treatment.  The system  proved relatively efficient for dialysis and ultrafiltration but it was heavy and  required intensive preparation. (Figure  6).

Fig. 6: Assembly of the Alwall kidney

Moreover in preparation the cellophane membrane was often perforated during the winding up and the process had to be repeated. The device required pre-priming with about 1.5L of blood and  post-transfusion reactions were not uncommon. In practice, it could be used only once in a day, as the preparation for the treatment (washing, winding up, and sterilization) required about 4 hours, followed by a treatment which lasted 6-10 hours. Despite these drawbacks. there was significant interest in the design worldwide, a single example was imported into the UK and used at Newcastle upon Tyne for about a year before being replaced by the Baxter Kolff system.

The safety features of these early systems were limited: there were no alarms, temperature or pressure monitors, blood leak detectors, or air embolism detectors and use necessitated medical and nursing supervision throughout.

 1960-1985: Vascular access

The period 1960-1985 was characterised by rapid technical developments driven by the availability of the Scribner shunt which permitted repeated access to the patients circulation. The shunt  was a quick connect/disconnect device surgically placed into to either the patient’s forearm or leg. (Figures 7 & 8) .

 

 

 

 

 

It consisted of two cannulae that were externalized via subcutaneous tunnels  so that they emerged distally from the cannulation site. The external parts of the shunt were connected with a small piece of Teflon when not in use,  and when required for vascular access, were clamped, separated and  connected to the extracorporeal circuit to provide access to the patient’s circulation. Whilst permitting repeated access to the circulation, they were prone to thrombosis, infection, and dislodgement. Shunts  disappeared from use by late 1960s when superveded by the  surgically created arteriovenous fistula, in which  an artery and a vein in the patient’s arm were surgically connected, resulting in a series of dilated vessels into which needles could be  inserted to withdraw and return blood, an  approach  that remains in use today.

1960-85: Haemodialysers

During the early 1960s the Travenol Twin coil  was the most commonly used artificial kidney. By the 1970’s a number of other manufactures were also producing coil dialysers.  In the UK the coil dialyser was manufactured by Avon Medicals/Capon Heaton Co.Ltd  (Birmingham). In 1960 Frederik Kiil in Norway developed a flat plate dialyser. The dialyser was intended to be used without a blood pump due to its low internal resistance and consisted of a stack of three heavy polypropylene boards, enclosing two pairs of membrane sheets  The sheets were soaked in a sterilizing solution and, while still wet, were placed onto the boards whose membrane contacting surface was grooved  Preformed blood ports were placed between the membranes at each end of the assembly during building and small holes to match those in the polypropylene boards were cut to permit the dialysis fluid to flow through the assembly when in use (Figure 9).

Fig. 9: Assembly of a Kiil dialyser

Following assembly the dialyser was tested for patency by pumping air into the membrane pairs and noting any drop in pressure. Failure to meet the pressure test meant either partial or total rebuilding of the stack. Following a satisfactory pressure test the dialyser was sterilized using formalin and stored until required. Prior to use the dialyser was connected to the cold water supply and the formalin rinsed out. Residual formalin was assessed by using Schiff’s reagent. The dialyser was then connected to the dialysis fluid supply and the blood side primed with saline prior to connecting the patient. The design was not patented resulting in the device being manufactured in Europe and the United States. In the UK it was manufactured by Heppell Engineering[1] and Watson Marlow, The membranes used were centrally supplied by the Ministry of Health and were produced by Enka Ag ( Wuppertal, Germany) although British Cellophane Ltd ( Bridgewater) experimentally produced undried cellulose gel sheet membranes  for a short period in the mid-1970s. By contrast with the commonly used Cuprophan sheets the membrane produced by British Cellophane was in the form of a roll stored in 1% formalin.

By 1973 the more efficient multipoint dialyser, (Meltec, Bourne End, Bucks) was available (Figure 11).

This was a licence built version of the dialyser manufactured in the US by Western Gear Corporation (Everett, Wa). It retained the external characteristics of the Kiil dialyser, but differed internally in that the membranes were supported by a series of small pyramids obtained by crosscutting the longitudinal grooves used in the Kiil design. This  offered a reduced blood membrane contacting area and a better mixing of the dialysis fluid though its passage along the support matrix compared to the Kiil dialyser. It was assembled in a manner identical to that described earlier.

The burden of building the dialyser was recognised and  many dialysis units reused rather than built the dialyser for each treatment; an approach extended into home haemodialysis.  For a short period  premanufactured membrane inserts manufactured by Bier Laboratories (Bishop Auckland, Co. Durham) were available as an alternative to rebuilding. The Dylade DS dialysis machine (1976) offered automated reuse of parallel flow dialysers and their extracorporeal circuit.

With availability of a reliable method of access and the coil and flat plate dialysers,  a number of hospitals in the UK began to treat patients with chronic renal failure. By 1964 at Newcastle upon Tyne, patients were treated at the Royal Victoria Infirmary (RVI) on a medical ward annexe. A central tank dialysis fluid supply, the contents of which were manually mixed before each treatment, was used. The tank supplied a number of locally manufactured variants of the Michelsen coil pots fitted with a recirculating pump and the Travenol Twin Coil. (Figure 12) .

The volume of the pot was 3-4L and the dialyser was held in place by a stainless steel bar.  A pump at the base of the pot recirculated the dialysis fluid through the dialyser and the level or volume of fluid in pot was maintained by an outflow at the top of the pot with fresh fluid being added at the bottom. An inflatable cuff around the coil ensured that the dialysis fluid flowed through rather than around the coil when in use.

In 1965, as part of the national expansion of renal services, a regional outpatient dialysis centre was established at the Ear Nose and Throat Hospital at Rye Hill in the west end of Newcastle. Patients at Rye Hill Hospital used the Kiil dialysers also linked to a central supply (Figure 13).

The flow through the dialysers was maintained by a flow meter and needle valve against which a small pump drew the dialysis fluid through the dialyser to waste.

Monitoring of the treatments at both locations was minimal  and confined to pressure measurement in the extracorporeal circuit. A common problem with the central supply was that it was prone to bacterial contamination, which could minimised by the inclusion of the refrigeration unit.  Water treatment at this time was non-existent with dialysis fluid made up using untreated tap water.

Central evaluation and commissioning

In 1965  the Ministry of Health set up a committee under the chairmanship of Professor Hugh de Wardener which made recommendations to coordinate the growing availability of haemodialysis in the UK, and to address more practical matters such as the choice and standardisation of equipment ( via a central purchasing and supply list)  and the career structure of staff.  Additionally there was concern from clinicians that the equipment would not perform correctly, and the working party requested that the Ministry of Health carry out independent trials of all equipment before being placed on a central supply list.  This led to the establishment of evaluation programmes at Newcastle ( for dialysers) and at the Atomic Weapons Research Establishment ( AWRA) Aldermaston ( for machines)

1960-85:  Haemodialysis machines

The coil dialysers were initially used with the Baxter delivery system described above. By 1967-8 the original concept had been re-engineered as a Recirculating Single Pass (RSP) system which also added monitoring of the dialysis fluid temperature, pressure monitoring and a flow meter (Figure 14).

At Newcastle upon Tyne, rather than switching to the re-engineered RSP concept, a locally manufactured variant of the original tank approach was used, but with a 240  litre tank system (Figure 15).

The increase of the tank size meant that a four hour dialysis could be completed without the need to change the dialysis fluid.

In the United States, Babb in collaboration with Scribner in 1964, developed the forerunner of the widely used  single patient haemodialysis machine. The design  was commercialised by Milton Roy (St. Petersburg, Florida USA) and became the Milton Roy Model A. The system incorporated a solid state logic circuit, permitted sterilization using hot water,  provided alarms for the arterial and venous pressures in the circuit and incorporated pretreatment alarm testing. It also incorporated a duplex proportionating pump allowing the dialysis fluid concentrate to be mixed with water in the appropriate ratio for clinical use.  In 1965, Dylade Ltd (Runcorn)  began the manufacture in the UK of  Milton Roy haemodialysis machines under licence (Figures 16 &17).

Fig. 16: Front and side views of the Dylade B3 dialysis machine

Dylade Ltd was founded by the family of Stanley Shaldon with the idea of providing support for patients receiving home haemodialysis, following Stanley’s demonstration of the feasibility of overnight unattended hospital and home haemodialysis in 1963-4 at the Royal Free Hospital. The first British single patient dialysis system was developed at the QE Hospital Birmingham in conjunction with the Joseph Lucas Research Centre ( Birmingham) and built commercially by G&E Bradley (Neasden, London) (Figure 17).

The  Lucas Mk I machine was offered by the Ministry of Health on central contract by 1968, together with the  Dylade B1 and the Cambridge Instruments Mk V  (Figure 18).

These early  machines were either chemically sterilized by the introduction of  formalin into the hydraulic circuit after use which was flushed out before the next use( Lucas I) or used hot water pasteurization ( Cambridge Mk V and Dylade B1). This first generation dialysis machines were similar in design concept to the original Milton Roy A dialysis machine  but incorporated some technical differences.. The monitoring parameters were identical  and all lacked the ability to measure blood flow rate, ultrafiltration or fluid removal during treatment, or to provide protection from air entering the patients circulation. The bubble trap in the venous segment of the extracorporeal circuit provided some protection, but required continuous visual monitoring during treatment. By the early 1970s stand alone level detectors were fitted to machines used either in hospital or in the home.

Many of the machines produced in the UK used peristaltic blood pumps manufactured by Watson Marlow, in which the pumping speed could be manually adjusted. The pumps were identical to the flow inducers manufactured by the company for industrial purposes.  Peristaltic pumps were also used for the infusion of heparin during treatment although by the mid-1970s they had been replaced by syringe drivers manufactured either by Sage or Vickers Instruments as they  offered greater accuracy in anticoagulant delivery compared to the peristaltic pump.

In 1968, the Ministry of Heath was dissolved and its functions together with those from the Ministry of Social Security were transferred into the newly created Department of Health and Social Security, which retained the responsibility of equipment used in haemodialysis.

Home haemodialysis

With the availability of single patient dialysis systems, and demonstration of the feasibility of treating patients in their  home in the early 1960s, home dialysis was widely utilised.  By 1971, 59 % of the patients treated in the UK were undergoing treatment in their own home. (Figure 19).

Some insight into dialysis in 1972 can be found in Hansard ( Volume 842  Column 1691) in which the then Undersecretary of State for Health and Social Security (Mr Michael Alison) stated: the cost of a machine alone is about £2,000, to which must be added the cost of building and engineering works required. The annual maintenance per patient is up to £2,500. There is the problem of finding enough qualified and trained staff to do the job.

Nevertheless, despite these difficulties there are today no less than 39 units in operation in hospitals in England and Wales, and the latest available figures show that 526 patients are being maintained on dialysis in these units. Between 1966 and 1971 £1·3 million has been allocated for the capital cost of providing for dialysis in hospital and at home. Running costs total between £2 million and £2·5 million a year, roughly half of which is for hospital and half for home dialysis patients. I mention these figures because I think it is important to put on record the not inconsiderable sums devoted to this service direct from the Exchequer—and I hope my Hon. Friend will not be too hard on the Exchequer—to provide facilities for what is in effect a very small number of patients, and patients who, had they been similarly stricken a decade ago would certainly not be alive today.

Apart from this expenditure, other costs are met by local health authorities which, exercising their powers contained in Section 12 of the Health Services Act, 1968, are expected to provide for the patient a room large enough to contain the equipment, the necessary stores, dressings and fluids, etc., and the patient’s bed. A sink with a good supply of water, adequate electrical fittings, a waterproof floor and washable walls and ceiling must also be provided. This provision is normally provided by adapting a room, or adding a room to the patient’s existing home. Where this is not possible, a prefabricated unit to house the equipment, may be provided. In some cases, it is necessary to re-house the patient. The cost of a home adaptation can range from £200 to over £1,000. The cost of a prefabricated unit is over £1,350

In Newcastle , home haemodialysis training began  in 1968-9 in a side room attached to the Professorial Medical Unit at the RVI, and a purpose built home haemodialysis training unit with six beds was opened shortly thereafter. Patients were trained to use the Lucas Mk I dialysis machine with the Kiil ( and later the Multipoint) dialyser.  By 1975, 66%. of  UK patients were being treated at home. Treatment was generally three times weekly with each session lasting 8 hours or longer. To support patients at home, Newcastle in common with  other dialysis units had a dedicated home dialysis nurse who visited the patients as well as a home haemodialysis administrator to manage the   logistical aspects relating to home treatment and to deal with the complexities of housing conversions or Portacabin placement.  Home water treatment initially was a water softener which was later replaced by a deionizer.

One of the problems experienced by home patients in Newcastle was the inadequate deaeration offered by the Lucas Mk I system which led to air bubbles in the dialysis fluid pathway reducing treatment efficiency and the formation of froth in the bubble trap. This was because cold water contains more dissolved air than warm water and when cold water is heated in the dialysis machine it becomes supersaturated with dissolved air. and the excess air comes out of solution.  The DHSS was made aware of this problem, resulting in the redesign of the deaeration system in the second generation of the Lucas machines ( Lucas Mk II)  which became available for clinical use by 1973-4. (Figures  20 & 21).

Fig. 20: Lucas Mk II dialysis machine

Fig. 21: The hydraulic circuit of the Lucas Mk II. The large white unit in the centre provided the enhanced de-aeration capability 

Other manufacturers also introduced design improvements around this time. The Lucas Mk  II offered an enhanced deaeration system, hot water rather than chemical sterilisation, and a fibre optic linked level detector. There was also a move away from pressure gauges to the use of pressure transducers The Kiil and the Multipoint dialysers continued to be used  both in the hospital and in the home.

To permit haemodialysis patients to have holidays away from their home, machines became available using small volumes of dialysis fluid which was regenerated. They were used by a number of dialysis units including Newcastle. The REDY (REgeneration of DialYsate) machine produced by Organon Teknika (Oss, Netherlands) was one such system which  used sorbents to remove solutes and toxins from used dialysate, purify and reconstitute it, and recirculate it through the dialyser. Water use per treatment was about 6 litres. (Figure  22).

A small portable dialysis system was also developed and manufactured in the UK by TecMed  (Portadialysis 101) but  it was not widely used.

Outbreaks of hepatitis in renal units in the early 1970s meant that patients in the home were switched to using disposable dialysers. All home patients at Newcastle were issued with a disposable flat plate dialyser which was used in the event of a blood leak. The dialyser issued was the Gambro Ad Modum Alwall dialyser (Figure 23).

 

With the advent of the Lundia plate dialyser this became the standard device in routine use (Figure 24).

 

Dialysis for acute renal failure

The home built recirculating tank systems used with the coil dialyser for the treatment of acute renal failure were also replaced. Disposable dialysers were now used in conjunction with the Nycotron ADPAC. ( Nycotron, Drammen, Norway) The ADPAC was  a small and compact dialysis system weighing under 30 kg and which could be autoclaved at 120^oC and also  incorporated a servo controlled proportionating system.(Figure 25).

The dialysis system  was temperamental necessitating frequent technician intervention. This frequent call for technicians led to the introduction of their  “twenty minute guarantee” meaning that the repair was not expected to last longer than 20 minutes.  By 1976 the Nycotron ADPAC system had been replaced with Bellco Unimat dialysis machine manufactured by Bellco SpA  (Mirandola, Italy). The Unimat used aviation grade electronic components and  offered a fully disposable dialysis fluid circuit, single needle dialysis  and bicarbonate buffered dialysis fluid. (Figure  26).

 

Disposable dialysers

In the mid to late 1960s several  European, US and Japanese manufacturers began  producing disposable dialysers. Initially only  flat plate or coil designs were produced. Variants of the coil dialyser were produced which could be used at a low dialysis fluid flow rate in conjunction with a dialysis machine without the need for a stand alone recirculation unit. Other refinements in the coil’s design were the change in membrane support and the encasement of the assembly in a perspex casing.

Some flat plate designs like the Dasco SP 400  (vDasco SpA, Mirandola, Italy) were hybrid devices in which a reusable frame was combined with a totally disposable pre-sterilised dialyser. Many of the dialysers produced at this time were used at Newcastle in connection with the dialyser evaluation programme but the one type which was used routinely in the treatment of patients was the flat plate dialyser manufactured by Ab Gambro.   Gambro was established in Sweden (Lund)  in 1964 and had UK representation by the late 1960s. It was  founded by a Swedish industrialist Holger Crafoord and its name was  derived from the abbreviation of the Gamla Brogatan (Old Bridge) Street in Stockholm, where Crafoord’s “Old Bridge Street Medical Supplies Company” was located.

The first l disposable flat plate dialyser  was produced in 1967. The Ad Modum Alwall dialyser  was a multilayer flat plate design made partly from metal. ( Figure 23) , used at Newcastle as a backup for home patients using the rebuildable Kiil dialyser.  In 1972 it was replaced by Gambro Lundia Subsequently the Gambro plate design underwent a number of iterations: Lundia Nova ( 1973), Lundia Optima ( 1975), Lundia Plate ( 1978),  and Lundia N (1982) which incorporated a transparent casing. The 7^th generation system variant produced in 1986 (Lundia IC) retained the clear casing but had integral dialysis fluid connectors and incorporated a  new blood distribution manifold. These were all used at some point in Newcastle.  One of the features of the disposable parallel plate dialyser was the ability to manufacture a device with differing surface areas merely by changing the number of layers within the device.(Figure 27).

The first hollow fibre dialyser was produced in 1968 by the Cordis Dow Corp.(Miami, Fl, USA), a 50-50 venture between Dow Chemical Company and Cordis Corp,  makers of specialist surgical equipment.  Early versions of the dialyser were shipped containing formalin to maintain sterility and were subject to performance variability, and clotting risk.  The monopoly of hollow fibre devices being produced by a single manufacturer was broken in 1969 when Enka Ag began the production of cuprophan hollow fibres.  This led to  several dialyser manufacturers to expand their product range to include hollow fibre devices.

The membranes in clinical use in the late 1960s to mid 1970s  had a low hydraulic permeability and were subject to considerable variability. The absence of technology to monitor or control the rate of fluid removal during treatment meant that many dialysis patients underwent dialysis using a weigh bed, or had to periodically step onto the scales to establish the fluid loss. Various researchers working independently during that time period attempted to solve these problems by developing ultrafiltration monitoring systems. One such system was developed in the UK by Repgreen Ltd based in Manchester (Repgreen UFM 1000) which was produced for a short period ( 1977-1979) (Figure 28).

The system monitored ultrafiltration by two electromagnetic flow sensors to measure the difference between dialysis fluid flowing into and coming from the dialyser.   The system lacked accuracy and required recalibration during use . The company ceased production of the device in 1979 and the patents relating to the device were  purchased by Gambro, who redesigned and improved its accuracy. It was marketed as a module of the Gambro AK-10 dialysis system  and was known as the Gambro UFM 10-1. The module was upgraded by the mid 1980s to the FCM 10-1 to provide ultrafiltration control and was also incorporated into the later  Gambro AK-100 dialysis system.

As well as a low hydraulic permeability, the membranes in use at this time removed only low molecular weight solutes from the blood. Interest in the removal of other compounds followed from experimental work using more  permeable membranes which culminated in the introduction of the AN69 membrane  a high permeability synthetic membrane in 1971. Initially it was produced in sheet form, and was used in the Rhone Poulenc RP 6 dialyser. The membrane needed to be used with a specially designed dialysis fluid supply system ( Rhone Poulenc Rhodial 75[2]) which permitted the control of fluid removal. The dialysis fluid was batch made and held in a 75L tank. A pump was used to remove fluid from the tank which was set to the required ultrafiltration rate. As both the blood and dialysis circuits were closed any fluid removed from the dialysis circuit was replaced by the equivalent amount of fluid from the patient’s blood circuit (Figure 29).

Following on from the ability to control ultrafiltration, interest in removing solutes by filtration (convective solute removal) and combining diffusive and convective solute removal followed.  Haemofiltration was initially performed using bagged infusion fluid for the replacement of fluid,  but by the mid 1980’s it was possible to produce the infusion fluid on line reducing cost. Further adaptation of the dialysis fluid circuit enabled haemodiafiltration to be performed  (Figure 30).

In the late 1960s with the availability of synthetic membranes interest focused on the bio(in) compatibility of membranes based on cellulose leading to the development of modified cellulose membranes in which the bioreactive OH groups were replaced. These membranes offered a bridge to the later synthetic membranes in use today.

Haemodialysis machines in the 1970s

Although the UK used mainly domestically produced haemodialysis machines, by the mid 1970s overseas manufacturers were also producing such machines, whiches began replacing the older British manufactured machines in the late 1970s. Early foreign manufactured machines used widely in the UK were the Gambro AK 10 (1977) (Figure 31), the Cobe Laboratories Centry2 (Cobe Laboratories Inc, Lakewood Co, USA) (1976) (Figure 32), and the Fresenius 2008 (1979) (Figure 33). Fresenius, based in Germany, began to sell the dialysis machines and dialysers of other manufacturers in the late 1960s but only began producing its own design of dialysis machine in 1979.

Fig. 31:  Gambro AK-10 dialysis machine; Fig. 32: Cobe Centry system 2 dialysis machine; Fig. 33: The Fresenius 2008 dialysis machine

These later variants were technologically more complex. The Gambro AK 10  was the first dialysis machine that used a microprocessor ( Intel 8080), remaining  in production until 1995,when it was replaced by the Gambro AK100.  These Gambro machines unlike others being produced at this time had a modular design.

Until 1976-77 all dialysis machines used acetate buffered dialysis fluid, due to problems with calcium carbonate formation if bicarbonate was used. Once this problem was overcome  by the use of  dual-concentrate, (acid and bicarbonate or base concentrate), the use of bicarbonate-based fluid became standard and this was reflected in the dialysis machine technology.  Further refinements of machine technology over this period included the introduction of ultrasonic level/bubble detectors ultrafiltration control systems  and the use of transducers for pressure measurements.  International Standards relating to safety in respect of machines and performance in respect of dialysers were also developed over this period and remain in use today.

The introduction of more sophisticated equipment into clinical practice meant that more specialist technical support was needed, leading to the appointment of the first generation of renal technicians with electromechanical experience. Most of these early technicians came into the health service from other industries. For example in Newcastle the technicians employed had previously worked for locally based engineering, shipbuilding companies or the National Coal Board.   DHSS interest in dialysis continued and in 1975 they organised an inaugural meeting for  renal technicians at Fallowfield, Manchester  which led to the formation of the Association of Renal Technicians ( now the Association of Renal technologists) (Figure 34).

Fig. 34: Attendees at the inaugural meeting of the Association of Renal Technicians. Back row, first left is Alan Strong, the RVI chief technician 

The DHSS was also instrumental in  establishing forerunners of the common standards relating to haemodialysis machines in use today.

Single needle dialysis

Conventional dialysis requires   two needles to provide vascular access during treatment. As  some patients found  it difficult to insert a second needle,   dialysis systems  were developed which cold use only a single needle (Figure 36),  linked to a mechanical system that switches between withdrawing and returning blood to the patient.

Fig. 35: An example of the single needle used for unipuncture

The  original solution to this problem was to occlude the venous and arterial line alternately by means of a lever which flicked rapidly across from one to the other. The blood pump pushed blood into an expanding dialyser for a few seconds then sucked on an empty line for the next few seconds while the dialyser drained into the patient. The rate of switching was determined by pressure or time both of which could be adjusted (Figure 36).

Fig. 36: The Gambro Single needle system occluded the venous and arterial blood lines intermittently ( dependant on operator set time or pressure)

While such an approach worked with compliant dialysers,  the introduction of the hollow fibre dialyser meant an alternative approach was needed, which was developed at the University of Gent, and commercialised by Bellco SpA ( Mirandola Italy). It was simply  the insertion of a second blood pump into the circuit. which accelerated the drainage phase and gave the operator complete control over the pressure in the blood compartment; indeed this system permitted the use of high flux dialysers in open circuit for the first time. Despite the intermittent flow through the dialyser, its efficiency at a given flow rate per minute was the same as that with a conventional two needle, continuous flow arrangement (Figure 37).

Fig. 37: Bellco double pump single needle system

The double pump arrangement was adopted by other manufacturers including Cobe Laboratories (Figure 38).

Fig. 38: Cobe Centry system fitted with a second blood pump to permit single needle dialysis

Unipuncture proved popular with patients in Newcastle and for many it was adopted as the standard practice, however its use  around the UK remained  limited. It tended to be reserved   for patients in whom there were problems with vascular access despite the fact that under such circumstances it was difficult to obtain a clinically desirable blood flow rate. This was because the average flow rate in a double pump system is dependent upon the maximum flow rate attainable.

 1985-2005: Industry consolidation

During this period there was consolidation in the industry. In 1984 Baxter acquired the dialysis machine division of Extracorporeal Medical Specialties, Dylade was acquired by Fresenius in 1986. In 1987, Gambro acquired Hospal and in 1990 it acquired Cobe Laboratories. Also in 1990, Althin Medical (Ronnerby, Sweden) , acquired CD Medical, and in 2000 Althin Medical was acquired by Baxter.  Probably the largest and most impactful of the industrial consolidation was in 1996, when Fresenius announced that it was going to spin off its own dialysis division and merge it with its U.S. subsidiary, Fresenius USA, and also with National Medical Care, to create a new company called Fresenius Medical Care, the world’s largest vertically-integrated company in the dialysis market.

1985-2005: Changing patient demographics

Over this period,  both the clinical mix of patients receiving treatment  and where they received treatment changed. The dialysis undertaken previously at Rye Hill in Newcastle moved to a purpose built dialysis unit at the newly built Freeman Hospital, whilst the decline of home haemodialysis demand (by 2001 <3% of UK patients were being treated at home) meant that the home dialysis training unit at the RVI was repurposed as an outpatient dialysis unit.  Many of the patients receiving treatment were elderly with  co-existing diseases such as diabetes, so their vasculature often did not permit the formation of arteriovenous fistulae which meant that the use of subclavian catheters became widespread.

 1985-2005: Haemodialysis machines  and haemodialysers

During this period, technology developments slowed, and there was increased emphasis on treating complications associated with regular dialysis treatment.  Manufacturers focused on introducing  machine refinements  for a more “physiological” dialysis.  Ultrafiltration monitoring and control became a integral element of machines using either a fluid balancing mechanism based on a refined version of the earlier Rhodial 75 approach or by the accurate differential flow measurements such as those based on the Coriolis effect. The use of rebuildable flat plate and coil devices diminished in favour of the smaller and more compact disposable hollow fibre and flat plate designs. By 1990, with the consolidation of manufacturers, Gambro remained the only major manufacturer producing disposable flat plate dialysers (Lundia Alpha)  and these were discontinued in 2001. Ttoday the use of hollow fibre dialysers is universal.

By 1985, all UK production of dialysis machines had ceased. The last machine produced in the UK was the Lucas 2100 (Figure 39) however it failed to gain market share and the company ceased production.

Fig. 39:  Lucas 2100 dialysis machine

In  the absence of domestically produced dialysis machines, there was an inevitable shift towards using dialysis machines manufactured in Europe or the United States. In   Newcastle the Lucas II machines were replaced with the Hospal Monitral S and the BSM 22 Blood module which if needed could be adapted for single needle dialysis  The system offered acid and/or bicarbonate dialysis fluid production, control of ultrafiltration and an  ultrasonic blood level detector. By 1994 the Monitral systems were being replaced by the Hospal Integra machines whose design was based on low volume hydraulics, computer based electronics, and a graphical user interface which offered a flexible architecture allowing continuously upgrades of the machine and included the ability to add various monitoring systems (Figure 40).

Fig. 40: Hospal Integra system in use in Newcastle  in 2006

Also used at this time were the Althin Tina (Figure 41)  and the Braun Dialog (Figure 42) dialysis machines.

Fig. 41: Althin TINA dialysis machine

Fig. 42:  Braun Dialog dialysis machine

 Conclusion

By 2005 haemodialysis had become a widely utilized and established method of treatment for renal failure in which nurses played a major role in the delivery of treatments. Haemodialysis had matured and moved from a miracle treatment to a mainstream treatment which could be applied at multiple locations and in which the earlier technical issues had been eliminated. Improvements in technology particularly in the dialysis machine hydraulic pathway considered novel in the 1980s became standard.   Although the generation of dialysis machines in use were more complex than those used in the 1960s, personal experience and informal information exchanged with colleagues in the dialysis industry suggests that the introduction of standards in the early 1980’s minimised poor equipment design or equipment malfunction.

By 1986, there were no UK producers of haemodialysis machines, and all dialysers used were manufactured abroad. UK manufactured products were confined to haemodialysis concentrates, fistula needles and blood tubing sets. The reasons for the shift away from domestically produced products to those manufactured overseas has not received academic study. One contributing factor was undoubtedly the central approach adopted by the Ministry of Health and later by the DHSS which meant that UK manufacturers had a ready and growing domestic market and there was little need for UK manufacturers to invest or innovate.

Notes

[1] Olga Heppell was first treated at Newcastle upon Tyne by Dr David Kerr. Her husband was an engineer, and following transfer to the Royal Free Hospital constructed the dialyser for her and later produced it commercially. Unlike the Watson Marlow built devices, which had a white frame, those manufactured by Heppell Engineering were unpainted aluminium.

[2] Rhone Poulenc withdrew from the field of dialysis in the late 1970s  with Hospal taking over the technology

Authorship

Nicholas Hoenich. First posted Nov 2024.

Last Updated on November 18, 2024 by neilturn