peritoneal

[per″ĭ-to-ne´al] pertaining to the peritoneum.peritoneal dialysis a type of hemodialysis in which the peritoneum surrounding the abdominal cavity is used as a dialyzing membrane for removal of waste products or toxins accumulated as a result of renal failure. Substances that can be removed in this way include crystalloids such as urea, creatinine, electrolytes, and drugs such as the salicylates, bromides, and barbiturates.
The exchange of substances across this type of semipermeable membrane involves three physical processes: diffusion, osmosis, and solvent drag. In diffusion the random motion of the molecules of solids, liquids, or gases in solution causes a flow of each solute from regions of high concentration to regions of low concentration. Diffusible solutes, those with molecules small enough to pass through the pores of the membrane, flow from the side on which the concentration is high to the side on which it is low. Osmosis is a flow of water molecules (or some other solvent) through the membrane. The flow moves from the side on which the concentration of nondiffusible solutes, those with molecules too large to pass through the membrane pores, is low (and thus there is more water) to the side on which the concentration is high (and there is less water). Solutes with molecules of intermediate size are not retarded in their flow through the membrane, but their flow is subject to solvent drag, that is, the rate at which a solute flows through the membrane is increased by a solvent flow in the same direction and decreased by a solvent flow in the opposite direction.Indications and Contraindications. Peritoneal dialysis has the advantage of being more quickly initiated than hemodialysis because a dialyzing machine is not needed, anticoagulants are not necessary, and there is no need for vascular cannulization. Also, since chemical and fluid exchanges occur more slowly, there is less stress on internal organs.
Acute and chronic renal failure are among the most common indications for peritoneal dialysis. Other indications are heart failure" >congestive heart failure and difficult or absent access" >vascular access. Since certain drugs can be removed by this method of dialysis, some types of drug poisoning can be treated in this way. Peritoneal dialysis cannot be used when there is severe abdominal trauma, multiple abdominal surgical procedures, adhesions, severe coagulation defects, paralytic ileus, or previous diffuse peritonitis.The Procedure. Fluid equal in osmolarity and similar in chemical composition to normal body fluid is introduced into the peritoneal cavity via a catheter. The fluid infuses by gravity; its rate of flow can be controlled by lowering or raising the container of dialysate or by manipulating the occlusive clamp on the tubing.
The length of time the dialyzing solution is left in the peritoneal cavity depends on the molecular weight of the substance to be removed and the amount of dialyzing solution used. Substances with low molecular weights equilibrate in two to three hours, while those with high molecular weights can take more than 12 hours to move across the membrane and equalize the concentrations of the two solutions. This period of equalization is sometimes called the “dwell time.” It is followed by a period of drainage to complete the dialysis or to prepare for instillation of fresh dialysate.
Peritoneal dialysis is done in one of three ways: Intermittent peritoneal dialysis (IPD) can be done manually or with an automated cycling machine. The dialysate is introduced, allowed to dwell for a specified number of minutes, and then drained. Automated IPD is usually done while the patient sleeps. Continuous ambulatory peritoneal dialysis (CAPD) is performed continuously by the patient on an outpatient basis. The dialysate fluid dwells for four to eight hours: the drainage bag is clamped, folded and held in the person's clothing during this time. When the dwell period is over, the catheter to the drainage bag is unclamped and the dialysate fluid is drained by gravity. A new bag of dialysate is then started and the process goes on over a 24-hour period. Continuous cycling peritoneal dialysis (CCPD) involves the use of a cycler for exchanges while the client sleeps. The last exchange before the patient arises for the day is allowed to dwell for the day, avoiding the interruption of daily activities for maintenance of the system.
Because hemodialysis is more efficient in removing toxins from the blood and body fluids, it has always been the treatment of choice for end-stage renal disease. There are certain patients, however, who fare better on less drastic and gentler dialytic therapy and who can benefit from continuous ambulatory peritoneal dialysis. The procedure is becoming an accepted alternative for persons with either chronic or acute renal failure.Complications. The most obvious complication of peritoneal dialysis is peritonitis, which is a real danger to any patient receiving this treatment. Contamination of some part of the system, a malfunctioning piece of equipment, contamination of the fluid, and infection of the catheter site are all possible sources of peritonitis. The catheter itself can cause complications through leakage at the site of insertion, infection, and occlusion of the perforations on the catheter. Respiratory difficulty can occur as a result of fluid retention that increases pressure against the diaphragm, and fluid overload that requires the more frequent use of hypertonic solutions. Fluid depletion and hypotension are also possible complications.Patient Care. To avoid complications strict adherence to aseptic technique is essential. If there is any break in the tubing connections during the procedure the peritoneal cavity must be considered contaminated. If the tubing becomes blocked the physician should be notified immediately.
An exchange record is kept of the fluid that is introduced into and withdrawn from the peritoneal cavity. The amount withdrawn is expected to closely approximate or be slightly more than the amount introduced. The exchange record contains information about the starting time of infusion, amount infused, concentration of fluid and drugs added, finishing time of infusion, starting time of drainage, volume of drainage, and total patient fluid loss (−) or retention (+) up to the time of recording. Since this last item is frequently a source of error, it is essential that all personnel involved in the dialysis procedure know how the recording is done. Daily weight on a stretcher scale facilitates calculation of fluid loss or gain.
The peritoneal drainage fluid is observed for cloudiness and the presence of blood or other abnormal constituents. The vital signs are recorded at frequent intervals so that early signs of shock or the development of an infection can be discovered. Respiratory difficulty may develop as a result of pressure of the fluid against the diaphragm. Mild dyspnea may be relieved by elevating the head of the bed. Severe dyspnea may necessitate immediate drainage of the fluid from the peritoneal cavity and collaboration among health care professionals to ensure the patient's safety.

Manual peritoneal dialysis via an implanted abdominal catheter (Tenckhoff's catheter). From Ignatavicius and Workman, 2002.

per·i·to·ne·al

(per'i-tō-nē'ăl), Relating to the peritoneum.

peritoneal

adjective Relating to the peritoneum.

per·i·to·ne·al

(per'i-tō-nē'ăl) Relating to the peritoneum.

peritoneal

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peritoneal

peritoneal

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