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                                          Dialysis

Dialysis is the movement of fluid and molecules across a semi-permeable membrane
from one compartment to another. Dialysis is a technique in which substances move
from the blood through a semi-permeable membrane and into dialysis solution
(dialysate). It is used to correct fluid and electrolyte imbalances and to remove waste
products in renal failure. It can also be used to treat drug overdose.

Clinical indications for dialysis
-GFR < 15ml/min
-certain uremic complications: encephalopathy, neuropathies, uncontrolled hyperkalemia,
pericarditis, accelerated hypertension

Types of Dialysis
-Peritoneal Dialysis (PD)
-Hemodialysis (HD)

Peritoneal Dialysis (PD) – done by staff
-PD catheter is inserted through an anterior abdominal wall. Prototype of catheter is
Tenckhoff. 60cm long; silicone rubber tubing; Dacron cuffs anchor catheter and prevent
migration of bacteria down the shaft from skin. Within weeks, fibrous tissue grows into
the Dacron cuff, holding catheter in place and physical catheter to bacteria. Distal end of
catheter is located in the peritoneal cavity.

Preparation for pt. before insertin of PD catheter includes:
-consent
-voiding
-bowel movement
-prevention of perforation
-weight

Discharge Instructions:
-care of catheter
-management of catheter

Before starting Peritoneal Dialysis, waiting period 7-14 days is usual before using newly
inserted catheter. This allows for proper sealing of the PD catheter and for tissue to grow
around the cuff. Two to four (2-4) weeks after insertion of PD catheter, insertion site
should be clean, dry and free of redness and tenderness. Once catheter site is healed, pt.
may shower.

Dialysis Solution Volume **the higher the % the more fluid is exchanged
-dialysis solution is packaged in clear, flexible plastic bags
-dialysis solutions are available in volumes of 1.2, 2.0, 2.5, 3.0 L
-standard volume prescribed is 2.0 or 2.5 L
-exchange volume is dictated primarily by the size of the peritoneal cavity



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-average size adult can usually tolerate 2L Exchanges
-smaller pts., those with pre-existing pulmonary disease, abdominal wall or inguinal
hernias may need to have reduced exchange volumes

Dialysis Solution Concentration
-Dextrose is the osmotic agent commonly used in dialysis solution
-Concentration of 1.5%, 2.5% & 4.5% Dextrose are standard
-Dextrose as an osmotic agent in PD has advantages of being familiar, relatively safe, and
inexpensive and source of calories.
-Limitation is that it predisposes pt. to hyperglycemia, dyslipidemia, obesity and long
term peritoneal membrane damage
REMEMBER: risk for infection b/c glucose environment causes bacterial attraction
-Standard 1.5% Dextrose dialysis solution will exert an osmotic pressure to remove 50-
150cc/per hour when using a 2L volume and 60 minute exchanges
-higher dextrose dialysis solutions 4.5% will exert an osmotic pressure to remove 300-
400cc/hr.
-Continuous use of 4.5% dextrose exchanges can theoretically remove up to 7-9L of fluid
a day and cause marked hypernatremia.
-Once pt. is euvolemic, resume 1.5% for all exchanges

Dialysis Solution pH
-pH of dialysis solution is lowered during manufacturing process to prevent carmelization
of glucose during heat sterilization
-low pH of dialysis solution has an adverse effect on leukocytes (predisposition to
infection). Even brief exposure to such low pH solutions causes “stunning” of
leukocytes, impairing for phagocytosis, bacteria killing
-bicarbonate based solutions are being explored

Dialysis Solution Temperature
-dialysis solutions are warmed to body temperature prior to inflow
-dialysis solution can be administered at room temperature, but uncomfortable lowering
of body temp. and shivering can result
-best warmer is heating pad or specialized warmer devices
**do not use microwave

Dialysis Solution Additives
-potassium
-heparin
-insulin
-antibiotics

When injecting any medication into dialysis solution ABSOLUTE STERILE
TECHNIQUE MUST BE USED. PREVENT BACTERIAL CONTAMINATION OF
DIALYSIS SOLUTION & PERITONTIS.




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Potassium dosage: 4mEq/Liter. Failure to add potassium to dialysis exchange may
result cause hypokalemia b/c glucose absorption and correction of acidosis with
peritoneal dialysis promotes the shift of potassium back into the cell, lowering the
extracellular potassium level.

Heparin dosage: 1000Units/2L
Sluggish dialysate flow from catheter obstruction by fibrin clots may occasionally be
seen in acute peritoneal dialysis

**Don’t forget to check lab values

Insulin-Regular
1.5% Dialysis- Regular insulin 8-10 Units
2.5% Dialysis- Regular insulin 10-14 Units
4.25% Dialysis- Regular insulin 14-20 Units

Because glucose may be absorbed from the dialysis solution, supplemental insulin may
be required for the diabetic pt.

**Don’t forget to check lab values

Antibiotics
Intra-peritoneal administration of antibiotics is efficient and provides an alternative rout
for pts. with poor vascular access

**Don’t forget to check lab values

Exchange Time
This is the combined time required for inflow, dwell and drain

Inflow
Dwell- ordered by MD
Drain – open flow

These three phases are equal to one Exchange time

Inflow
-inflow is by gravity usually requires about 10 minutes (200cc/minute)
-inflow time is dictated by the volume to be infused and the height of the dialysis solution
above the pts. abdomen
-inflow time may be prolonged due to kinking of tubing or increased inflow resistance by
intra-abdominal tissues close proximities to the catheter tip.
-during inflow of dialysis solution, some pts. may experience pain or cramping. This
may result from hypertonic solution and acidic nature of the peritoneal solution
-these complaints usually decrease with time, but may be relieved with slowing the
dialysis solution for a few exchanges



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-otherwise, inflow should be kept to a minimum to maximize the dialysis effectiveness.

Dwell Time
-dwell times is the amount of time that the dialysis solution remains in the peritoneal
cavity
-it is the time the end of flow to the beginning of outflow (drain)
-4-hour exchanges (this means the “dwell time is 3.5 hrs; allotting 10 minutes inflow
time; 20 minute drain time)

Outflow Time
-Outflow time is the amount of time allotted to drain the dialysis solution from the
peritoneal cavity.
-outflow is usually 20 minutes
-outflow depends on the total volume to be drained, the resistance to outflow and the
difference in height between the pt.’s abdomen and drainage bag.
-in pt.s with large abdomens, first EXCHANGE may not drain completely (often 1-1.5L)
-as long as marked abdominal distention is not present, a second exchange of 2L can be
cautiously instilled.
-subsequent drainage usually proceeds normally.
*REMEMBER: what you put in, you should get out.

Fluid Balance
-monitor fluid balance with each exchange
-monitor running total
-keep pt. in negative balance
-weigh every day at same exchange cycle
-clinical assessment
-s/s of ECFV-Excess (fluid overload) or ECFV-Deficit (dehydration)

**have pt. rotate abdomen between exchanges

Complications of Peritoneal Dialysis
-Abdominal Distention: may result from incomplete drainage of dialyses solution.
Discomfort, distention, respiratory compromise may result.
-Peritonitis: major complication of PD. Is though to occur most often b/c of improper
technique in making or breaking a transfer set-to-bag or catheter-to-catheter set
connection. This allows bacteria to gain access to the peritoneal cavity via the catheter
lumen. Bacteria present on the skin surface can also enter the peritoneal cavity via the
catheter tract. Within months of catheter placement, PD catheters become covered with
bacteria laden-slime plaque. It is unknown whether such plaque has a role in
pathogenesis of peritonitis. Peritonitis may also be due to bacteria of intestinal origin that
enter the peritoneal cavity by migration through the bowel wall.
-PD leukocytes are critical in combating infection that enter the peritoneal space. A
number of factors are now known that alter the WBC efficacy in killing invading bacteria




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Dialysis solution pH and Osmolarity
PD solution has a pH close to 5.0 and an osmolarity ranging from 1.3-1.8x that of normal
plasma, depending on the glucose concentration. These unphysiological conditions
greatly inhibit the ability of the peritoneal leukocytes to phagocytize and kill bacteria.
High osmolarity, low pH and presence of lactate combine to cause inhibition of
generation of neutrophils.

Signs/Symptoms of Peritonitis
-abdominal pain & tenderness
-rebound tenderness
-N/V
-fever
-feverish symptoms
-chills
-diarrhea or constipation
-cloudly peritoneal fluid
-blood leukocytosis

-Cloudiness in most pts. the sudden onset of cloudly fluid with appropriate abdominal
symptoms is sufficient evidence of peritonitis to warrant initiation of antimicrobial
therapy. However, cloudiness may be due to the presence of fibrin rather than increase in
WBC count.
-Peritoneal fluid-culture: normally the PD contains predominantly mononuclear cells
(macrophages, monocytes and to a lesser extent lymphocytes) Eosinophils and basophils
are usually absent. The % of neutrophils does not exceed 15% of total non-erythrocyte
cell count and a value greater than 50% strongly suggests peritonitis; > 35% should raise
suspicion.
-Hernia Formation
-Abdominal Wall & Pericatheter Leak
-Genital Edema
-Respiratory Complications
        Hydrothorax: under the influence of raised, dialysate can travel form the
        peritoneal to the pleural cavity, leading to a pleural effusion composed of dialysis
        effluent.
-Back Pain: the presence of dialysis solution in abdominal cavity both raises IAP and
swings center of gravity forward, producing lordotic stress on lumbar vertebrae
-Metabolic Complications
        Glucose Absorption: glucose is standard agent used in PD solution as an osmotic
        agent. Glucose has the advantage of being cheap, stable and relatively nontoxic
        To peritoneum. However, it is easily absorbed across peritoneal membrane.
-Lipid Absorption
        -Total Cholesterol-High
        -LDH Cholesterol-High
        -HDL Cholesterol-Low
        -Triglycerides- Very High
**Extreme elevation of triglycerides predispose the pt. to pancreatitis.



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Protein Loss
PD is associated with significant protein loss across the peritoneum. Around 5-10g of
protein is lost into dialysate fluid each day. The loss is increased with peritonitis. The
major component of the protein loss is ALBUMIN, but IgG accounts for up to 15%.
These losses are the major reason why peritoneal dialysis pts. tend to have a lower serum
albumin levels than pt. on hemodialysis. Acute inflammation, as seen peritonitis, is
associated with substantially greater protein losses, and a rapid reduction in serum
albumin is common during acute episodes of peritonitis. Unresolved peritonitits is
associated with protracted and exaggerated protein losses causing protein malnutrition.
Protein loss has become an indicator to terminate (permanently or temporarily) PD.

Complications
-hypo/hypernatremia
-hypo/hyperkalemia
-hypo/hypercalcemia
-hypo/hyperphosphatemia

Temporary Percutaneous Catheters
Emergency dialysis access is best achieved using a temporary percutaneous route, with
central venous annulation through the femoral, subclavian, external jugular, or
internal jugular veins. This technique will preserve the peripheral vessels as sites for
long-term access. Subclavian or jugular vein catheterization is generally used if the pt. is
likely to require hemodialysis, as the catheter may be left in place for weeks. In the
critically ill pt. requiring immediate dialysis, the femoral route may also be used for
short-term access. In the past, two venous catheters were required for hemodialyses, one
for venous inflow and the other for venous outflow. However, the double-lumen single
catheter technique is now the most popular, with blood withdrawn and reinfused through
the different ports of the same catheter.

Advantages of Temporary Percutaneous Catheters
-relative ease of insertion
-immediate availability for use
-catheter placement patent for weeks

Acute Complications associated with percutaneous catheters
-pneumothorax (related to the experience of the physician)
-inadvertent arterial puncture
-arteriovenous fistula
-thoracic duct injury
-brachial plexus injury
-laceration of the subclavian vein
-air embolism




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Chronic complications
-catheter sepsis
-thrombosis (catheter)
-Thrombosis of subclavian vein or internal jugular vein: this will cause arm or neck
swelling; removal of the catheter often will reduce it. However, this complication may
create a problem with long-term access due to venous hypertension in the extremity.

General Access Devices Guidelines
-use an arm rather than a leg. Preferably, this should be nondominant extremity. **No
B/P in arm where catheter is inserted.
-place access sites are distally as possible to the limb. This allows proximal sites to be
available for subsequent procedures.
-avoid atherosclerotic vessels.
-do not let implanted material penetrate the skin
-allow for ease of access to the site
-use prophylactic antibiotics when a synthetic graft is required

-Thrombosis remains the most common complication. The risk of occlusion depends on
the graft material, location of the arteriovenous shunt, and diameter of the pts. vessels.
-Infection
-swelling of the arm secondary to subclavian vein stenosis or thrombosis with venous
hypertension may produce massive edema of the arm. This occurs with increasing
frequency as the use of temporary subclavian or internal jugular vein catheters for
dialysis increases. Ligation of the arteriovenous fistula may be necessary to reduce
massive swelling of the arm.
-aneurysm of the graft is the consequence of weakening from repeated punctures.
-hematoma

Complications of Hemodialysis
-hypotension
-muscle cramps
-loss of blood
-coagulation problems (too much Heparin)
-hepatitis
-sepsis
-disequilibrium syndrome


**TAKE TEMPERATURES 4X DAILY B/C HIGH RISK FOR INFECTION WHEN
YOU HAVE SOMETHING INSTILLED (CATHETER)




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