Principle of Dialysis:
Dialysis works on the principle of diffusion of solutes across a semipermeable membrane. Blood flows by one side of a semipermeable membrane, and a dialysis solution or fluid flows by the opposite side. Smaller solutes pass through the membrane. The concentrations of undesired solutes (for example potassium, urea, and phosphorus) are high in the blood, but low or absent in the dialysis solution and constant replacement of the dialysate ensures that the concentration of undesired solutes is kept low on this side of the membrane. The dialysis solution has levels of minerals like sodium and chloride that are similar to their natural concentration in healthy blood. For another solute, bicarbonate, the dialysis solution level is set at a slightly higher level than in normal blood, to encourage diffusion of bicarbonate into the blood, to neutralize acidosis that is often present in these patients.
There are two main types of dialysis - hemodialysis and peritoneal dialysis. Hemofiltration is not strictly speaking a dialysis treatment, but is extremely similar.The principle of hemodialysis is the same as other methods of dialysis; it involves diffusion of solutes across a semipermeable membrane. Hemodialysis utilizes counter current flow, where the dialysate is flowing in the opposite direction to blood flow in the extracorporeal circuit. Counter-current flow maintains the concentration gradient across the membrane at a maximum and increases the efficiency of the dialysis.
Fluid removal (ultrafiltration) is achieved by altering the hydrostatic pressure of the dialysate compartment, causing free water and some dissolved solutes to move across the membrane along a created pressure gradient.
We observed 2 clients with chronic renal failure who required hemodialysis.
Length of the procedures was 3 hours according to dialysis prescription.
Indications for Dialysis
Acute Indications:
1) Hyperkalemia
2) Metabolic Acidosis
3) Fluid overload (which usually manifests as pulmonary edema)
4) Uremic pericarditis, a potentially life threatening complication of renal failure.
5) And in patients without renal failure, acute poisoning with a dialyzable drug, such as lithium, or toxin.
Chronic Indications:
1) Symptomatic renal failure.
2) Low glomerular filtration rate (GFR) (RRT often recommended to commence at a GFR of less than 10-15 mls/min/1.73m2)
3) Difficulty in medically controlling serum phosphorus or anemia when the GFR is very low
Nursing actions before, during and after procedure: Nurse checks dialysis prescription to identify parameters for setting up dialysis machines, time and duration of dialysis session; prepares dialysis machine and line with dialyzer; measures patient’s weight before procedure; perform patient’s assessment: history, reactions to previous procedures, measures vital signs initially and then every 15 minutes, if stable, and records to the chart; setup the access (an intravenous catheter, an arteriovenous (AV) fistula, or synthetic graft) and connects to preconfigured plumbing - creating a complete loop through the pump and filter; observes patient during dialysis to detect complaints and abnormalities, reports significant changes to the MD; controls the dialysis machine and responds to alarms; at the end of the prescribed time, the patient is disconnected from the plumbing, which is removed and discarded; needle wounds (in case of fistula) are bandaged with gauze, held for 5-10 minutes with direct pressure to stop bleeding, then the taped in place; measures temperature, blood pressure, and weight to confirm the removal of the desired amount of fluid; verifies that the patient is in condition suitable for leaving the unit.
Equipment: The hemodialysis machine performs the function of pumping the patient's blood and the dialysate through the dialyzer. The dialysis machines are highly computerized and continuously monitor an array of safety-critical
parameters, including blood and dialysate flow rates, dialysis solution conductivity, temperature, and pH; as well as dialysate for evidence of blood leakage or presence of air. If any reading is out of normal range, an audible alarm will sound to alert the nurse who is monitoring the patient.
Location of dialyzing membrane: dialyzing membrane is located inside of the dialyzer. The dialyzer is a piece of equipment that actually filters the blood. Almost all dialyzers in use today are of the hollow-fiber variety. A cylindrical bundle of hollow fibers, the walls of which are composed of semi-permeable membrane, is anchored at each end into potting compound (a sort of glue), and then this assembly is put into a clear plastic cylindrical shell with 4 openings.
Assessment procedure for access to the client blood stream:
Nurse identifies patients’ mode of access (central venous catheter, AV fistula or AV graft). Sometimes its difficult to distinguish between a fistula and a graft, but it is necessary for using a correct technique (tourniquet is not used with AV graft, can cause damage). Nurse assesses the site for signs and symptoms of infection: redness, swelling, elevated temperature.
4. Important aspects of a client assessment: Before each treatment starts, it’s important to assess blood pressure, pulse and temperature. The amount of weight the patient has gained since last treatment is an important factor in dialysis. The nurse examines the patient for swelling and listens to the heart and lungs. After the patient has been on dialysis for several weeks, the dry weight will be defined. Dry weight is the amount client weighs when his blood pressure is normal and body fluids are balanced. A certain amount of weight gain occurs between treatments. This will vary from patient to patient, but the average daily weight gain between treatments should not exceed 1 to 2 pounds. Gaining too much fluid may make the treatment more difficult. If the patient ignores his diet plan and drinks too much fluid or eats too many salty foods, he'll put himself at risk of developing serious complications, like edema, high blood pressure, shortness of breath and even congestive heart failure. Removing the excess weight gain due to fluid can lead to cramps and discomfort during dialysis. Also, if the client gained too much weight, the dialyzer may not be able to remove all of the extra fluid. It is crucial, then, to keep track of the weight as part of the hemodialysis routine
5. Role of the nurse in the care of the client on dialysis and stress factors: Nurse operates a dialysis machine. That includes turning it on, putting the lines in place,
priming the air out of the lines with saline, sets the goals, bloodflow rates, and other parameters for individual patients treatments, troubleshoots the many alarms that go off. Nurses carefully assess each patient before and after the treatment. She’s responsible to enter the doctor’s orders and change the medicine book accordingly, each month does progress notes on each patient, and monthly report on the access.
Dialysis nursing is fast paced and can be hectic; there is pressure to get the patients on and off the machines in a timely manner, while maintaining every safety precaution.
Complications and nursing interventions:
The sudden removal of fluid on dialysis may cause side effects, which are usually proportionate to the amount of fluid which is removed. These potential side effects include low blood pressure, fatigue, chest pains, leg-cramps and headaches.
Since hemodialysis requires access to the circulatory system, patients undergoing hemodialysis have a portal of entry for microbes, which could lead to septicemia or an infection affecting the heart valves (endocarditis) or bone (osteomyelitis). The risk of infection depends on the type of access used. Bleeding may also occur.
Mannitol or Saline is given when someone's blood pressure has dropped down too low. There is almost an instant improvement in BP when a patient is put into the trendelenburg position. Each person’s sodium profile is formulated by setting the sodium variance on the machine. The sodium variance setting and the UF options have the effect of drawing the fluid off in increments rather than constantly. This gives the vascular system a chance to catch up to the fluid loss more naturally thereby decreasing incidents of low blood pressure and cramping.
Client’s activity during procedure: our clients demonstrated effective coping with the dialysis procedure. During the procedure they were both sleeping comfortably.
Psychological effect of dialysis: Depression is the most common psychological problem in the dialysis population. The diagnosis of depression in dialysis patients is confounded by the fact that several symptoms of uremia mimic the somatic components of depression. It affects the physical, psychological and social well being of the dialysis population. Other psychological problems associated with dialysis are anxiety, and hostility. Every dialysis patient should be seen by the dialysis social worker at initiation of dialysis, and at least biannually thereafter, to assess the patient's psychological state, with specific focus on the presence of depression, anxiety, and hostility.
Psychosocial nursing diagnoses: powerlessness related to need for treatment to live despite effects on lifestyle; interrupted family process related to interruptions in the role responsibilities caused by treatment schedule; disturbed body image related to presence of dialysis access site.
Teaching aspect: includes diet for the patient on dialysis, teaching about right access care.
Dietary regimen: The goals of nutritional care in the management of ESRD are: to prevent deficiency and maintain good nutritional status (growth, in the case of children) through adequate protein, energy, vitamin, and mineral intake; to control edema and electrolyte imbalance by controlling sodium, potassium, and fluid intake; To prevent or retard the development of renal osteodystrophy by controlling calcium, phosphorus, and vitamin D intake; To enable patients to eat a palatable attractive diet that fits his or her lifestyle as much as possible.
Diet and fluid intake are modified through assessing the blood chemistry of the patient and assessing the patient for the presence of swelling. Generally fluid is restricted to 1500 ml per day. Potassium may be restricted. Potassium is found mostly in high-protein foods, fruits and vegetables. www.PassNurseExams.com