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DIALYSIS Dr. Frank Edwin
CAUSES OF RENAL FAILURE • Diabetes • Untreated high blood pressure • Inflammation • Heredity • Chronic infection • Obstruction • Accidents
1.Renal Failure Diagnosis • Symptoms: Anorexia, Nausea, Vomiting, Oliguria • ? Precipitating factors • Signs: Anaemia, Hypertension, Fluid Overload etc • Biochemistry: • Blood • Urea >7mmol/l • Creatinine >120umol/l • Electrolytes: Rising K+ • Creatinine Clearance (GFR <<120ml/l) • Urine: Proteinuria • May be Acute or Chronic • Acute – Reversible or Irreversible
2. Treatment Options • No Treatment • Monitoring & Predialysis • Control symptoms • Preserve Residual Renal Function • Control rising BP (Antihypertensives) • Control Renal Bone Disease (Ca2+, Vit D) • Prevent/Treat Anaemias (Erythropoietin, Blood) • Dialysis • Renal Transplantation
Dialysis Definition • Artificial process that partially replaces renal function • Removes waste products from blood by diffusion (toxin clearance) • Removes excess water by ultrafiltration (maintenance of fluid balance) • Wastes and water pass into a special liquid – dialysis fluid or dialysate
Types • Haemodialysis (HD) • Peritoneal Dialysis (PD) • They work on similar principles: Movement of solute or water across a semipermeable membrane (dialysis membrane)
Diffusion • Movement of solute • Across semipermeable membrane • From region of high concentration to one of low concentration
Ultrafiltration • Made possible by osmosis • Movement of water • Across semipermeable membrane • From low osmolality to high osmolality • Osmolality – number of osmotically active particles in a unit (litre) of solvent
Selection for HD/PD • Clinical condition • Lifestyle • Patient competence/hygiene (PD - high risk of infection) • Affordability / Availability
The process of diffusion 1.2. Blood cells are too big to pass through the dialysis membrane, but body wastes begin to diffuse (pass) into the dialysis solution. 3. Diffusion is complete. Body wastes have diffused through the membrane, and now there are equal amounts of waste in both the blood and the dialysis solution.
The process of ultrafiltration in PD 11. 22.Blood cells are too big to pass through the semi-permeable membrane, but water in the blood is drawn into the dialysis fluid by the glucose. 3.Ultrafiltration is complete. Water has been drawn through the peritoneumby the glucose in the dialysis fluid by the glucose in the dialysis fluid. There is now extra water in the dialysis fluid which need to be changed.
Dialysis process occurs outside the body in a machine The dialysis membrane is an artificial one: Dialyser The dialyser removes the excess fluid and wastes from the blood and returns the filtered blood to the body Haemodialysis needs to be performed three times a week Each session lasts 3-6 hrs Haemodialysis
Requirements for HD • Good access to patients circulation • Good cardiovascular status (dramatic changes in BP may occur)
Performing HD HD may be carried out: • In a HD Unit • At a Minimal Care / Self-Care Centre • At Home
HD Unit • Specially designed Renal Unit within a hospital • Patients must travel to the Unit 3x a week • Patients are unable to move around while on dialysis; may chat, read, watch TV or eat • Nursing staff prepare equipment, insert the needles and supervise the sessions
Minimal / Self-Care Dialysis • Patients take a more active role • Patients prepare the dialysis machine, insert the needles, adjust pump speeds and machine settings and chart their progress under the supervision of dialysis staff • Patients must travel to the unit 3x / week • Patients need to be on a fixed schedule
Home Haemodialysis • Use of machines set up at home • Machines have many safety devices inbuilt • Thorough patient training • Requires the help of a partner at home every time • Suitability is assessed by the haemodialysis team • Ideal for patients who value their independence and need to fit in their treatment around a busy schedule
HD Access • 2 types of access for HD: • Must provide good flow • Reliable access • A fistula: arterio-venous (AV) • Vascular Access Catheter
AV Fistula Access • Matures in about 6 weeks • Ensure good working order • Avoid tight clothing or wrist watch on fistula arm • Assess fistula daily; notify immediately if not working • Avoid BP cuff on fistula arm • Avoid blood sampling on fistula arm (except daily HD Rx) • Avoid sleeping on fistula arm • Grafts (synthetic) may be used to create an AV fistula
Vascular Access Catheter • Double lumen plastic tube • May be placed in Jugular, Subclavian or Femoral vein • May be temporary or permanent • Temporary – awaiting fistula or maturation • Permanent – poor vessels for fistula creation e.g. children and diabetics • Catheters must be kept clean, dry and dressed to prevent infection
Effects of HD on Lifestyle • Flexibility: • Difficult to fit in with school, work esp if unit is far from home. Home HD offers more flexibility • Travel: • Necessity to book in advance with HD unit of places of travel • Responsibility & Independence: • Home HD allows the greatest degree of independence • Sexual Activity: • Anxiety of living with renal failure affects relationship with partner • Sport & Exercise: • Can exercise and participate in most sports • Body Image: • Esp with fistula; patient can be very self conscious about it
Problems with HD • Rapid changes in BP • fainting, vomiting, cramps, chest pain, irritability, fatigue, temporary loss of vision • Fluid overload • esp in between sessions • Fluid restrictions • more stringent with HD than PD • Hyperkalaemia • esp in between sessions • Loss of independence • Problems with access • poor quality, blockage etc. Infection (vascular access catheters) • Pain with needles • Bleeding • from the fistula during or after dialysis • Infections • during sessions; exit site infections; blood-borne viruses e.g. Hepatitis, HIV
Peritoneal Dialysis (PD) • Uses natural membrane (peritoneum) for dialysis • Access is by PD catheter, a soft plastic tube • Catheter and dialysis fluid may be hidden under clothing • Suitability • Excludes patients with prior peritoneal scarring e.g. peritonitis, laparotomy • Excludes patients unable to care for self
Addendum to Principles (PD) • Fluid across the membrane faster than solutes; therefore longer dwell times are needed for solute transfer • Protein loss in PD fluid is significant ~ 8-9g/day • Protein loss ↑s during peritonitis • PD patients require adequate daily protein averaging 1.2 – 1.5g/kg/day • Other substances lost in the dialysate • Amino acids, water soluble vitamins, some medications and hormones • Calcium and dextrose are absorbed from the dialysate fluid into the circulation
Addendum to Principles (PD) • Standard dialysis solution contains: • Na+ – 132 mEq/l • Cl- – 96 -102 mEq/l • Ca2+ – 2.5 – 3.5 mEq/l • Mg2+ – 0.5 -1.5 mEq/l • Dialysis solution buffer: • Sodium lactate • Pure HCo3- • HCo3- /Lactate combinations • Lactate is absorbed and converted to HCo3- by the liver • Dextrose solution strengths: 1.5%, 2.5%, 4.25%
Types • Continuous Ambulatory Peritoneal Dialysis (CAPD) • Automated peritoneal Dialysis (APD)
CAPD • Dialysis takes place 24hrs a day, 7 days a week • Patient is not attached to a machine for treatment • Exchanges are usually carried out by patient after training by a CAPD nurse • Most patients need 3-5 exchanges a day i.e. • 4-6 hour intervals (Dwell time) 30 mins per exchange • May use 2-3 litres of fluid in abdomen • No needles are used • Less dietary and fluid restriction
APD • Uses a home based machine to perform exchanges • Overnight treatment whilst patient sleeps • The APD machine controls the timing of exchanges, drains the used solution and fills the peritoneal cavity with new solution • Simple procedure for the patient to perform • Requires about 8-10 hrs • Machines are portable, with in-built safety features and requires electricity to operate
PD Access • Done under • LA or GA
DIET • Why is diet important? • Managing the diet can slow renal disease • The need for dialysis can be delayed • The diet affects how patients feel
CONTROLLING YOUR DIET Foods to control are those containing: • Protein • Potassium • Sodium • Phosphorous • Fluid
PROTEINS Animal protein Dairy (milk, cheese) Meat (steak, pork) Poultry (chicken, turkey) Eggs Plant protein Vegetables Breads Cereals
Milk Potatoes Bananas Oranges Dried Fruit Legumes Nuts Salt substitute Chocolate MAJOR SOURCES OF POTASSIUM
SODIUM • Regulates blood volume and pressure • Avoid salt Use Alternate food seasonings: lemon and limes, spices, seafood seasoning, Italian seasoning, vinegars, peppers
FLUIDS • Healthy kidneys remove fluids as urine • Check for fluid and sodium retention • Need to restrict fluid intake
PHOSPHOROUS • Phosphorus is a mineral which combines with calcium to keep bones and teeth strong • Too little calcium and too much phosphorus • Need to control the phosphorus in the diet • Need to take a phosphate binder or a calcium supplement
VITAMINS • Folic acid • Iron supplements • Do not take OTC’s without consulting the doctor.
MANAGING YOUR DIET INDICATORS OF GOOD CONTROL: • Weight loss or gain • Blood pressure • Swelling of hands and feet • Blood samples
Haemoglobin Albumin Calcium Phosphorus GFR (24 hour urine) Sodium Potassium Urea Creatinine LAB MONITORING
Lifestyle Changes with PD • Flexibility • Can be performed almost anywhere • Least impact on work / school life (esp APD) • Travel • Dialysis supplies can be delivered to most parts of the world; travel more flexible. APD machines are portable; will fit into a car boot, can be carried by train/air • Responsibility • Requires more responsibility from patient but more independence
Lifestyle Changes with PD • Sports/Exercise • Most are possible • Advice on swimming, lifting, contact sports • Sexual Activity • May affect relations based on patient anxiety • Delivery & Storage of Supplies • Home delivery and storage • A month’s supplies – 40 boxes; space to store • Specially recruited and trained delivery staff
Problems with Treatment • Monotomy of treatment • The treatment never goes away against days off with HD • Body Image Problems • Esp with a permanent catheter • Abdominal stretching • Fluid Overload • Much less a problem than with HD • Dehydration • Less common than fluid overload • Abdominal Discomfort • Bloated feeling
Problems with Treatment • Poor drainage • Common problem esp with new patients • Fibrin plug • Catheter displacement • Leakage • Fluid may leak around catheter exit site. (May leak into scrotum) • Stop PD temporarily • Resite catheter (use new one) • Infections • Exit site infections • Tunnel infection • peritonitis
Problems with Treatment • Hernia • Aggravation of pre-existing herniae (repair) • Evolution of new herniae • Declining effectiveness of the peritoneum • e.g. repeated infection • Effect of glucose in the dialysis fluid