Technology overview | The NxStage System One NX1000‑1 home haemodialysis device for renal replacement therapy in chronic kidney disease | Advice

About the technology

CE marking

The NxStage System One first received a CE mark in April 2004. The current CE mark is held by NxStage Medical Inc. and has been valid since April 2014.

The individual components of the NxStage System One are listed below; all are CE marked as Class IIb medical devices other than the Express Fluid Warmer and the Fluid Warming System which are Class IIa:

The cycler.
Fluid warming devices:
- Express Fluid Warmer.
- The Fluid Warming System.
The dialyser sets, made up of:
- One of the following cartridges must be fitted to operate the system:
  - NxStage Cartridge CAR‑170 with pre‑attached dialyser
  - NxStage Cartridge CAR‑171 with pre‑attached dialyser and heparin line
  - NxStage Cartridge CAR‑172C with pre‑attached dialyser and LockSite medication ports (the manufacturer states that this cartridge is used in 95% of cases in the UK)
  - NxStage Cartridge CAR‑124 without pre‑attached dialyser
  - NxStage Cartridge CAR‑125B (available on a case‑by‑case basis for the paediatric population) without pre‑attached dialyser
- One of the following dialysers must be used. Dialysers are pre‑attached to all types of cartridges except for CAR‑124 and CAR‑125B. For these cartridges, the physician must decide which dialyser to use for each patient. These stand‑alone dialysers are manufactured by Asahi Kasei Medical.
  - Leoceed‑N16
  - Leoceed‑N21
  - Leoceed‑H16
  - Leoceed‑H21
The PureFlow SL integrated system for purification of tap water.
Dosing calculator software.

Description

The NxStage System One is a transportable haemodialysis device intended for use in the home or while travelling by adults and children suffering from stage 5 CKD. The device is operated using controls on the cycler user interface. The dialysis fluid for use with the NxStage System One can come from 2 sources. One option, mainly intended for use while travelling, is to use pre‑packaged, pre‑mixed sterile bags of PureFlow dialysis fluid that are heated to body temperature. There are 2 fluid warming systems that are compatible with the NxStage System One. The Express Fluid Warmer is compatible with all NxStage Cartridges except CAR‑124 and CAR‑125. If CAR‑124 or CAR‑125 are used, the dialysis fluid must be heated with The Fluid Warming System. The second option is for preparing dialysis fluid, is to make it in the home using tap water that has been purified using the PureFlow SL system. This purified water is then mixed with PureFlow sterile dialysis concentrate to give 40–60 litres of dialysate, and this is warmed in the PureFlow SL before use. This option is intended for use in the home. For each dialysis session a pre‑sterilised, single‑use NxStage cartridge (listed above) is required. Cartridges CAR‑170, ‑171 and ‑172C are pre‑attached to a dialyser. Cartridges CAR‑124 and ‑125B are not pre‑attached to a dialyser and, therefore, a dialyser will need to be selected and then attached to the cartridge before each dialysis session. NxStage offers cartridges without pre‑attached dialysers to increase clinician choice and flexibility of treatment.

The express fluid warmer sits on top of the cycler. All of the blood‑ and fluid‑containing circuits are contained within the treatment cartridges, so there is no direct contact between the cycler and the blood or the fresh dialysate.

The NxStage System One measures 38 cm x 38 cm x 46 cm and weighs 33 kg. The manufacturer states that the NxStage System One is smaller than conventional haemodialysis machines, and unlike current conventional haemodialysis systems the device can function with standard mains electrical and water supplies without the need for conversion of domestic supplies. The waste fluid is disposed of down a standard drain.

NxStage Medical lists 5 models of the NxStage System One device, which can perform a range of treatment functions for both acute and chronic forms of kidney disease. According to the manufacturer, only the NX1000‑1 model is available for use in the UK; in line with the scope of this briefing, the NX1000‑1 model is intended for home haemodialysis for people diagnosed with CKD. The other models listed by the manufacturer are CE‑marked but have not yet been officially launched in the UK.

Intended use

The NxStage System One is intended to provide haemodialysis in the home or while travelling, for people who have been diagnosed with stage 5 CKD. It is also indicated for the treatment of acute and chronic renal failure, or fluid overload using haemofiltration, haemodialysis, and/or ultrafiltration, in an acute or chronic care facility, but these uses are beyond the scope of this briefing.

Setting and intended user

NxStage Medical specifies in the NxStage System One User Guide and Instructions for Use that treatment with the NxStage System One must be prescribed by a clinician. In the UK, this may be either a doctor or a nurse independent prescriber. This treatment prescription will include:

the frequency and duration of haemodialysis
the cartridge model
the concentration of dialysate electrolytes
blood flow rates.

The manufacturer does not recommend use of the device unless users meet the following criteria:

have a dedicated caregiver or partner who is receptive to continual training
have stable vascular access
have a high standard of hygiene within the home to prevent infection and ensure safety

Both the person having haemodialysis and an accompanying caregiver need in‑depth training to use the device. NxStage Medical provides training for NHS staff, who in turn provide training to people who intend to have home haemodialysis with the NxStage System One. Training programmes are managed by the individual hospital departments. These can be tailored to match the needs of the person who will be having the treatment. For example, 2‑week intensive courses have been used for people already established with haemodialysis, whereas 3‑ to 5‑week programmes have been used for people who are new to haemodialysis.

The NxStage System One is intended for use in the home (or while travelling) to give greater flexibility to people needing RRT. The home environment also offers a more practical setting for changing treatment frequency compared with conventional in‑centre haemodialysis regimes. Home haemodialysis regimes often use shorter and more frequent sessions of haemodialysis or alternate nocturnal regimes. Regimes are often personalised to suit the need of the individual.

Several features of the NxStage System One, such as the integrated water purification system, its compact size and pre‑mixed dialysate fluids, are designed to allow home dialysis without needing significant changes to the home (Clark and Turk, 2004). The following facilities are needed for home dialysis with the NxStage System One:

A reliable mains water and electrical source.
Close access to a standard drain for waste disposal.
Adequate storage for a 2‑week supply of premixed dialysate or dialysis concentrate and consumables.
Caution should be taken with babies, young children and pets, to reduce the chance of interference with the system and the subsequent risk of infection.

Current NHS options

NICE's technology appraisal guidance on home compared with hospital haemodialysis for patients with end-stage renal failure recommends that people with stage 5 CKD should have a detailed assessment to determine the appropriate treatment option. If haemodialysis is considered to be a suitable treatment, the person's clinical and psychological suitability and social circumstances should be assessed before home haemodialysis is considered. Specifically, NICE recommends that people considering home haemodialysis must have '1 or more carers who have also made an informed decision to assist with the haemodialysis' and who are given the opportunity to voice their opinions independently of the person wishing to start home haemodialysis. Alternatively, NICE recommends that if the person having treatment for CKD is able to take responsibility for their therapy in a proactive manner, they may be able to manage their care independently ('on his or her own'). However, NxStage Medical states that therapy should not, in any circumstance, be done without a caregiver.

People intending to have home haemodialysis with the NxStage System One should consider the impact on their home. A suitable amount of space is needed to house the machine and the additional consumables. All home users must maintain a high level of cleanliness to prevent infection, particularly if small children or pets are present. An additional cost in utility bills should also be considered.

NICE is not aware of other transportable haemodialysis devices which are designed to be used at home or while travelling, without modifications to the home water or electrical supply.

Costs and use of the technology

The manufacturer did not provide a purchase price for the NxStage System One because it is negotiated on a cost‑per‑treatment basis. This cost varies depending on several factors, including the following:

The level of service for which NHS Trusts contract. This can vary, depending on the arrangements for delivery of the NxStage products, or whether any drugs or ancillary items are purchased from NxStage Medical.
The number of patients in the trust whose CKD is being treated using the NxStage System One. Tiered price discounts apply depending on the size of the patient group.
The number of treatments needed per patient, per week.
The volume of dialysate solution delivered per patient.

The manufacturer claims that across the range of programmes it offers, the price per treatment using the NxStage System One is approximately 60% of the current weekly NHS tariff cost for home haemodialysis. The 2014/15 weekly NHS tariff cost for home haemodialysis is £449 for adults aged 19 years and over. Alternative treatment options for dialysis and their associated costs are outlined in the table below (unit costs for each treatment from NHS Reference Costs 2012‑13, represented as a weighted average based on the activity and unit cost per DRG code).

Dialysis treatment option	Cost per session
Hospital haemodialysis	£157.92
Satellite haemodialysis	£148.18
Home haemodialysis	£138.67
Peritoneal dialysis	£65.26

Likely place in therapy

The NxStage System One is likely to be used as a home‑based treatment option for people with stage 5 CKD who need RRT.

Specialist commentator comments

All specialist commentators who reviewed this briefing felt that the NxStage System One could be used by people who do not have the support of a caregiver in their home. This is in disagreement with the manufacturer's criteria, which specifically exclude people who do not have a dedicated caregiver from using the NxStage System One.

The specialist commentators noted that additional training and specific safety measures could be put in place so that a person using this device without carer support could have access to immediate help should they need it. Two specialist commentators stated that people without caregivers who wished to have haemodialysis independently in the home had to sign a contract from the prescribing centre, confirming that they understood the risks of dialysing independently.

One of the specialist commentators noted that in addition to clinical end points, patient‑centred outcome measures were particularly important in considering the NxStage System One. Three of the specialist commentators highlighted the observed quality of life improvements using NxStage System One, and reiterated that patient choice should be prioritised. In general, specialist commentators noted that people who were given the opportunity to take control of their RRT using the NxStage System One described a positive effect on their quality of life.

The specialist commentators noted that the device's ease of use and flexibility meant that more people would be eligible for home haemodialysis. Furthermore, the simple user interface has made the NxStage System One a successful option for children and, as a result, children have been able to return to full‑time education and go on holiday, which are factors not necessarily considered in outcome measures in clinical studies. These factors are limited in the case of conventional haemodialysis, in‑centre or at home.

Two specialist commentators described their experiences of successfully using the NxStage System One in combination with adapted dialysis cartridges for treatment of CKD in children from 3 years of age and weighing less than 15 kg. They used the CAR‑124 cartridge and the CAR‑125B cartridge. Both these cartridges need to be attached to a separate dialyser, as selected by the physician, in order to function.

Equality considerations

NICE is committed to promoting equality and eliminating unlawful discrimination. We aim to comply fully with all legal obligations to:

promote race and disability equality and equality of opportunity between men and women, and
eliminate unlawful discrimination on grounds of race, disability, age, sex, gender reassignment, pregnancy and maternity (including women post‑delivery), sexual orientation, and religion or belief, in the way we produce our guidance (these are protected characteristics under the Equality Act 2010).

The NxStage System One is intended for people with stage 5 CKD. As a chronic condition, this is considered a protected characteristic as defined by the Equality Act (2010).

Home haemodialysis using the NxStage System One may improve quality of life outcomes. The treatment flexibility offered by the system may allow people using it to adjust their haemodialysis schedule around their work, school and social activities.

Jehovah's Witnesses may be opposed to haemodialysis (using any of the available technologies) because of their belief that blood should not be removed from the body.

The manufacturer states that users must have a dedicated caregiver who is willing and capable to have training on the use of the NxStage System One. Reliable access to mains electricity and water, adequate storage for a 2‑week supply of dialysis consumables, and access to a standard drain are also necessary. If these criteria cannot be met then physicians may choose to exclude these patients from using the NxStage System One.

Patient and carer perspective

The British Kidney Patient Association (BKPA) made the following comments on the device.

Flexible dialysis treatments such as the NxStage System One increase the likelihood of people using dialysis being able to return to work and to travel, which would improve their quality of life. However, nocturnal home dialysis can have a negative impact on quality of life: the machines can be noisy and this can stop the person having dialysis (and potentially their partner) from sleeping. Home dialysis can also make the user feel isolated because they are not in such regular contact with medical professionals, and so it is important that people having dialysis at home are not ignored. NxStage Medical suggests that respite programmes and continual consultation with health care professionals may help to mitigate this risk.

The BKPA highlighted that the needs of the carer should not be overlooked, and so they should be offered support. It noted that some people who do not have a caregiver at home may still choose to use home haemodialysis, although NxStage Medical states that users must have a caregiver in the home in order to use this system. Caregivers may become ill, making it difficult for them to assist the person using dialysis; this eventuality should be taken into consideration.

Finally, the BKPA highlighted the gap in the research literature concerning home haemodialysis and emphasised that both patient‑reported outcome measures and patient‑reported experience measures should be presented, in addition to clinical outcome measures.

The NICE Public Involvement Programme team highlighted additional equality considerations for people with visual impairment or learning difficulties who may be not be able to use home haemodialysis with the NxStage System One without additional support. People without a fluent grasp of English may also be excluded because of an inability to train continually without the help of an interpreter. However, the manufacturer states that its user guides are available in different languages.