Robert P. Popovich

The Moncrief-Popovich catheter : a new peritoneal access technique for patients on peritoneal dialysis

Existing catheter implantation techniques violate a fundamental premise of wound healing. The immediate presence of the catheter in the post operative surgical wound forms a passage for permanent colonization of the catheter tunnel and cuff(s). This is manifested by the almost universal presence of the biologic products of bacterial growth (biofilm) on the external and internal surfaces of these catheters. The Moncrief-Popovich catheter and implantation technique are designed to address this problem. The Moncrief-Popovich catheter is implanted in the standard fashion, except that the external segment of the catheter is buried subcutaneously at the time of implantation. After allowing 3-5 weeks for tissue in-growth in a sterile environment, a small incision is made in the skin through which the external segment of the catheter is exteriorized and attached to an adapter. A 2 year trial was conducted in 59 patients, comprising 530 patient-months of experience; the incidence of peritonitis was one episode for every 29.4 patient months. All but three of the patients used the standard spike exchange technique. In a recently initiated study using disconnect procedures in 63 of the 74 patients studied, the peritonitis rate was one episode for every 28.7 patient-months; patient- months have totalled 201.2 to date. There was a rate of one exit site infection every 12.57 patient-months. It was concluded that the Moncrief-Popovich catheter and implantation technique result in a substantial decrease in the incidence of peritonitis for patients using the standard spike exchange system

A Comparison of Peritoneal Transport in Patients with Psoriasis and Uremia

Peritoneal solute equilibration studies during prolonged intraperitoneal dwell were performed in patients with psoriasis and normal renal function, and compared to patients with renal failure undergoing peritoneal dialysis. Calcium, phosphorous, uric acid and protein equilibration were faster in uremics. No differences were observed for sodium and chloride. Mass transfer area coefficients (a measure of the mass transfer at infinite dialysate flow rates) were calculated for glucose, protein and uric acid and found to be complimentary to the results obtained by studies of solute equilibration. Possible reasons for the differences obtained are discussed.

Kinetics of Peritoneal Transport

A comprehensive mathematical model of the patient-peritoneal dialysis system is fundamental to the analysis and understanding of metabolite and fluid transfer which occurs during peritoneal dialysis. Mathematical models serve to: (1) illustrate the system parameters which are most significant, (2) define how these significant parameters relate to each other, (3) predict the behavior of the system, allowing manipulation of the variables to produce an optimized clinical result, (4) aid in the design of clinical protocols to measure the parameters, and (5) suggest areas requiring additional investigation. In short, a great deal of information can be acquired from modeling of the peritoneal dialysis system in general with multiple applications to specific patients.

Continuous Ambulatory Peritoneal Dialysis (CAPD)

Continuous Ambulatory Peritoneal Dialysis is the most common form of home dialysis and has become an increasingly utilized alternative method of treatment for patients with end-stage renal disease both in the United States and throughout the world (Figure 1). The increased patient population and renewed scientific interest in peritoneal dialysis is reflected in a major upsurge in scientific publications related to this procedure. A simultaneous decline in the use of home hemodialysis has occurred, and is probably attributable to the tremendous growth in CAPD.

Peritoneal membrane plasmapheresis

A novel process has been devised that uses the peritoneal membrane to remove plasma proteins from the body at a rate comparable to conventional extracorporeal plasma-pheresis. A vasodilator (4 mg histamine phosphate) is added to 1 liter of hypertonic solution (485 mOsmol/L), and infused intraperitoneally with a residence time of 4 hr. Plasma containing proteins is convected across the peritoneum through open pores into the cavity and removed. The next alternating infusion is with a hypotonic solution (214 mOsml/L) containing a vasoconstrictor (1.0 mg norepinephrine). This infusion restores the fluid removed from the subject in the previous exchange, and prevents the rapid fall-off in protein removal rates obtained with repeated infusions with vasodilators only. Peritoneal membrane plasmapheresis was successfully tested on canines, with protein removal rates of between 30% and 50% of total serum protein per day for 13 days over a 22 day period. Peritoneal membrane plasmapheresis represents a potentially inexpensive, continuous/nightly home treatment for protein mediated diseases treatable by extracorporeal plasmapheresis.

Continuous Ambulatory Peritoneal Dialysis (CAPD) — Worldwide Experience

CAPD has become an accepted alternative form of therapy for patients with end-stage renal disease. Rapid expansion in the number of dialysis units with experience in this form of therapy is occurring. As of Fall 1980, 261 dialysis facilities in the United States and an approximate equal number throughout the world have made CAPD available to most patients (Figure 1). An increase in this patient population is continuing and more than 2000 patients (near 2 to 3% of the dialysis patients in the USA) are presently undergoing CAPD (Figure 2).