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

Introduction

Chronic kidney disease (CKD) is the loss of kidney function. Symptoms may include tiredness, swollen hands and feet, shortness of breath, nausea and blood in urine. These symptoms usually do not present until CKD has reached an advanced stage, referred to as stage 5. The most common risk factors for developing CKD are hypertension (high blood pressure), diabetes and a family history of CKD (NHS Choices, 2012).

Kidney function is measured by estimating the glomerular filtration rate (GFR). This is a test to estimate how much waste fluid the kidneys can remove from blood in a minute. When a person's GFR is less than 15 mL/min/1.73 m², stage 5 CKD is diagnosed.

People diagnosed with stage 5 CKD often need renal replacement therapy (RRT) in order to sustain life. In 2012, 54,824 adults and 861 children and young people in the UK had RRT, with an incidence of 108 new people per 1 million population (Fogarty and Cullen, 2013).

A kidney transplant is considered the gold standard therapeutic option for people with stage 5 CKD who need RRT. In 2012/13, 3000 kidney transplants were done in the UK. Transplanted kidney survival rates are reported to be 85–95% after 1 year, 70–80% after 5 years and 50–60% after 15 years (NHS Choices, 2013b). People with CKD who are waiting for a transplant or who do not meet the inclusion criteria for transplantation have dialysis, unless they elect for palliative care. Dialysis is the process of filtering the blood to remove any harmful waste products, extra salt and water. There are two forms of dialysis: haemodialysis and peritoneal dialysis (NHS Choices, 2013a).

Haemodialysis is the removal of metabolic waste products from the blood through a semi‑permeable membrane. Blood is taken from the body through an arteriovenous fistula, intravenous catheter or synthetic graft (Fogarty and Cullen, 2013). The blood is passed into a dialysis machine which contains a semi‑permeable membrane (NHS Choices, 2013a).The blood flows past a counter‑flow of dialysate solution, and the waste products in the blood diffuse across the membrane into the solution. The dialysate solution contains ions such as sodium, calcium, potassium and magnesium, chloride and bicarbonate. The concentration of these ions is set specifically to meet each user's needs. People whose CKD is being treated with conventional haemodialysis may have to limit their fluid intake to 1.5 litres per day (less for children) and are subject to strict dietary controls to limit their intake of sodium, potassium and phosphorus (NHS Choices, 2013a).

Conventional haemodialysis can take place in a hospital, a satellite unit or at home. Each haemodialysis session lasts approximately 4 hours, and is repeated 3 times per week. NICE's technology appraisal guidance on home compared with hospital haemodialysis for patients with end-stage renal failure recommends that everyone who is suitable for home haemodialysis should be offered the choice. In 2012, 1080 people in the UK were using home haemodialysis (Fogarty and Cullen, 2013). People choosing home haemodialysis, and their caregivers, must take active responsibility for their treatment, but it has the potential to be clinically effective and provide an increase in quality of life for patients, family and caregivers (Hothi et al. 2013 and Young et al. 2012).

Peritoneal dialysis can also take place in either a health care setting or at home. In this treatment, metabolic waste products from the blood diffuse through the peritoneum (the semi‑permeable membrane that surrounds the abdominal organs) rather than through a synthetic membrane outside of the body. The waste products diffuse into dialysis fluid, which is added into the abdominal cavity. The dialysis fluid is added and removed from the body through a catheter, which is surgically inserted into the person's abdomen and remains in place permanently (NHS Choices, 2013a).