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Biomedical subjects

B F Prowant

Publications and source records attributed to B F Prowant.

71 records · Page 4Linked to original sources
PubMed1980

Peritonitis during continuous ambulatory peritoneal dialysis.

We initiated a therapeutic program of continuous ambulatory peritoneal dialysis for patients with chronic renal failure. Our program resulted in many episodes of peritonitis arising from contamination due to the technical aspects of the procedure. Microbiologic evaluation showed that 73% of 97 episodes were culture positive, with gram-positive organisms causing most of the cases, especially early in dialysis. Gram-negative rods tended to occur later. Gram stains of dialysate effluent resulted in a disappointingly low yield of only 9% positivity. Cell counts were a dependable indicator of the presence of peritoneal inflammation and also of therapeutic success. Most patients responded well to intraperitoneal cephalothin, 125 mg/L for 10 to 14 d. The occurrence of peritonitis resulted in 0.93 years of hospitalization during the total of 15.45 patient-years on dialysis, which essentially negated the financial advantages of this method of treatment of chronic renal failure. For this to be a successful mode of therapy, advances in the prevention of peritonitis must be made.

Adult↗
PubMedDate not supplied

Reproducibility of the peritoneal equilibration test in CAPD patients.

A study was undertaken to evaluate the short-term reproducibility of peritoneal equilibration test (PET) results. Nine patients with end-stage renal disease undergoing continuous ambulatory peritoneal dialysis underwent PETs under similar conditions on 2 consecutive days. Dialysate samples were obtained at 0 hours, midcycle, and at the end of exchange. There were no significant differences between the mean ratios at 4 hours for creatine, urea nitrogen, potassium and protein, and glucose between PET 1 and PET 2. A standard PET is highly reproducible when repeated under similar conditions. Reproducibility is better for ratios of creatinine, glucose, urea nitrogen, and potassium than for protein.

Aged↗
PubMedDate not supplied

A prospective study of the effect of noncompliance on small solute removal in continuous ambulatory peritoneal dialysis. Preliminary report.

In nine patients on continuous ambulatory peritoneal dialysis (CAPD) who were in stable condition, the authors measured the effects of an extra daily exchange on small solute removals and clearances and the measured/predicted creatinine production (M/P). The goal was to evaluate the sensitivity of M/P to single exchange noncompliance. Daily collections of urine and dialysate were performed on the usual prescribed program and on the next day with an extra exchange of usual exchange volume. The average increase in drain volume of 26% was associated with an average increase in M/P of 6%. The maximum M/P increase was 15%; the percentage increase in M/P correlated inversely with renal creatinine clearance. Daily total urea clearance normalized to total body water by dialysis and renal function increased 12%. Extrapolating these findings suggests that an average patient with a baseline M/P near 1.0 and renal creatinine clearance of 5 ml/min would require more than 50% drain volume noncompliance to yield a M/P of 1.24 on the complaint day. A 50% noncompliance may not yield a M/P greater than 1.0 on the first compliant day if baseline M/P is less than 0.94. The authors suggest monitoring daily urine and dialysis creatinine output because M/P creatinine is relatively insensitive to noncompliance (particularly in patients with residual renal function) and because there are questions about the accuracy of predictions in patients with renal failure using formulae established in different populations. The authors recommend simply monitoring total daily creatinine output and establishing patients as their own controls. The authors provide a table for the interpretation of changes in creatinine output in conjunction with changes in other routinely monitored parameters.

Blood Urea Nitrogen↗
PubMedDate not supplied

Repair of chronic peritoneal dialysis catheter.

BACKGROUND: Damage to the peritoneal dialysis catheter may be due to wear from long-term use, exposure to antibacterial agents (strong oxidants), and accidental injury from sharp objects. Repair of such catheter, if not associated with subsequent complications, would extend catheter life and reduce costs and patient inconvenience related to catheter replacement. OBJECTIVE AND DESIGN: Retrospective analysis of seven peritoneal catheters repaired 11 times over a 15-year period by splicing the old catheter with an extension tube using the Peri-Patch Repair Kit (Quinton Instrument Co., Bothwell, WA, U.S.A.). RESULTS: The life of these seven catheters was extended by a mean of 26 months (range 1-87 months), without increasing infection rates after splicing. The peritonitis rate after catheter splicing was 0.40 per year, not higher than the overall rate (0.76 per year) in our center during the same time period. Exit-site infections occurred in 6 patients after catheter splicing. Only one infection was related to trauma during the procedure and resulted in chronic exit infection; the catheter was eventually removed. In this patient, damage to the catheter was less than 1.5 cm from the exit site. CONCLUSIONS AND RECOMMENDATIONS: Splicing of the damaged peritoneal catheter, if properly done, is a safe procedure and can significantly prolong catheter life. We recommend that measures to prevent catheter damage, such as avoiding the use of scissors and other sharp objects, should be emphasized during the initial patient education and training. Alcohol and iodine should not be used on silicone rubber catheters. We suggest that the patient should report catheter damage immediately and come to the clinic within a few hours for catheter splicing (if possible) and prophylactic antibiotic to prevent peritonitis. Finally, we recommend that repair of the catheter should not be attempted if the breakage is less than 2 cm from the exit site, unless done as an emergency procedure if immediate catheter replacement cannot be performed.

Adult↗
PubMedDate not supplied

Nutritional markers during peritoneal dialysis: data from the 1998 Peritoneal Dialysis Core Indicators Study.

OBJECTIVE: This analysis explores the nutritional status of adult U.S. peritoneal dialysis (PD) patients. DESIGN: The Peritoneal Dialysis Core Indicators Study is a prospective cross-sectional prevalence survey describing the care provided to a random sample of adult U.S. PD patients. METHODS AND POPULATION: Prevalence data were collected from a national random sample of 1381 adult PD patients participating in the United States End Stage Renal Disease (ESRD) program. RESULTS: The median age of these patients was 55 years, 61% were Caucasian; the leading cause of ESRD was diabetes mellitus. Age, sex, size, peritoneal permeability, dialysis adequacy, and nutritional indices did not differ between patients on continuous ambulatory PD and patients on automated PD. The dialysis prescriptions employed achieved mean weekly Kt/V urea (wKt/V) and creatinine clearance (wCCr) values of 2.22 +/- 0.57 and 67.8 +/- 22.5 L/1.73 m2/week, respectively. The PD patients were large, with a mean body weight of 77 +/- 21 kg and body mass index (BMI) of 27 +/- 8.6 kg/m2. The mean serum albumin of these patients was 3.5 +/- 0.51 g/dL, and 43% of values fell below the National Kidney Foundation Dialysis Outcomes Quality Initiative's desired range. The PD patients had a normalized protein equivalent of nitrogen appearance (nPNA) of 1.0 +/- 0.57 g/kg/day, a normalized creatinine appearance rate (nCAR) of 17 +/- 7.3 mg/kg/day, and an estimated lean body mass (%LBM) of 62% +/- 18% of body weight. Serum albumin correlated positively with patient size, nCAR, and nPNA, but negatively with age, the presence of diabetes mellitus, female gender, erythropoietin dose, the creatinine dialysate-to-plasma ratio results of peritoneal equilibration testing, and the dialysis portion of the wCCr. The duration of ESRD experience correlated negatively with both serum albumin and patient size, although these relationships were complex. CONCLUSION: Peritoneal dialysis patients generally have marginal serum albumin levels, a finding incongruent with alternative measures of nutritional status, such as weight, BMI, and creatinine generation. Serum albumin is reduced in patients with high peritoneal permeability (i.e., rapid transporters) and, because these patients generally have higher than average wCCr values, serum albumin is inversely correlated with the dialysis component of the wCCr. The presumptive nutritional indicators (BMI, %LBM, nPNA, and serum albumin) provide disparate estimates, varying from 10% to 50% for the prevalence of nutritionally stressed PD patients.

Adult↗
PubMedDate not supplied

Long-term experience with Swan Neck Missouri catheters.

The Swan Neck Missouri catheters are designed to reduce major complications including 1) exit/tunnel infections, by a downward directed exit hole; 2) pericatheter leaks, by placement of the deep cuff in the rectus muscle; 3) catheter tip migration, by caudal direction of the intraperitoneal segment; and 4) outer cuff extrusion, by a permanent bend between the 5 cm or 3 cm spaced cuffs in SN-M2 and SN-M3 catheters, respectively. Between April 1986 and April 1990, 103 swan neck catheters were implanted. Comparison of prospective data from 103 swan neck catheters and retrospective data from 148 standard (Tenckhoff and Toronto Western Hospital) catheters implanted between January 1982 and June 1985 showed reduced complication rates with swan neck catheters. An overall survival of 64% at 36 months for swan neck catheters is significantly better than that of 29% for standard catheters.

Catheters, Indwelling↗
PubMedDate not supplied

Chronic nightly tidal peritoneal dialysis.

Nightly tidal peritoneal dialysis (NTPD) is a technique in which, after an initial fill of the peritoneal cavity, only a portion of dialysate is rapidly cycled. Five anuric, stable, PD patients entered a 4 month study to determine the NTPD session length necessary for clinically adequate dialysis and creatinine clearance similar to those on four daily 2 L CAPD exchanges. NTPD was performed using a modified PAC-X-2 cycler, with the drain phase regulated by a target volume. One patient completed 3.5 months of study, one 4 months, three 6 months, and one patient each continued on NTPD for 13, 14, and 32 months. The mean NTPD session time was 9 hr 24 min (range 8 hr 35 min to 9 hr 55 min) at the end of 4 months. All patients had clinically adequate dialysis. Three patients preferred NTPD over CAPD, particularly because of an empty abdomen during the daytime. One patient required an increase in NTPD time, and an addition of one daytime exchange, because of low creatinine clearance. In conclusion, NTPD provides weekly creatinine clearances comparable to CAPD, with an acceptable duration of nightly dialysis sessions in most anuric patients. A new PD machine providing inexpensive dialysis solution in large quantities, as well as safe and false alarm free dialysis sessions, is needed for practical NTPD implementation.

Blood Urea Nitrogen↗
PubMedDate not supplied

Leukocyte kinetics in patients with peritonitis on long-term peritoneal dialysis.

Dialysate and blood leukocyte counts were measured during 130 episodes of peritonitis in 91 hospitalized patients on long-term peritoneal dialysis (CPD). The authors found that the blood/dialysate leukocyte count can be less than 1.0, and this is usually the case when dialysate leukocyte count exceeds 20,000/mm3. Dialysate leukocyte removal in a single 2 L drain bag can approach the leukocyte number in the entire circulating blood volume. Daily drainage can remove leukocytes in amounts exceeding the blood leukocyte pool 2 to 3 fold. The observed blood leukocyte counts throughout a range of 2,700 to 10,000 at dialysate leukocyte counts greater than 20,000 per mm3 may reflect: 1) leukocyte removal approaching maximum bone marrow output of leukocytes, and/or 2) increasing microcirculatory margination of leukocytes in those episodes of peritonitis associated with very high dialysate leukocyte counts.

Cells, Cultured↗
PubMedDate not supplied

Calculation of 6-hour D/P creatinine ratio from the 4-hour peritoneal equilibration test. The effect of dwell duration on the results.

OBJECTIVES: Since the introduction of the peritoneal equilibration test (PET), the 4-hour dialysate/plasma creatinine (D/P Cr) has been used by several authors for determining continuous ambulatory peritoneal dialysis (CAPD) prescriptions. However, the results have been unsatisfactory because the 4-hr D/P Cr does not accurately reflect the D/P Cr in 24-hr collections. The PET and the 24-hr dialysate collections differ in the duration of dwell and the tonicity and volume of dialysate, all of which influence the equilibrated D/P Cr. It can be assumed that the D/P Cr in 24-hr collections in these patients is closer to a 6-hr D/P Cr. Because a 6-hr PET is inconvenient, we developed a mathematical model to calculate the 5- and 6-hr D/P using the results of a standard PET. DESIGN: In a retrospective analysis, D/P Cr ratios in 24-hr collections and D/P Cr ratios calculated from a mathematical formula were correlated. Using a mathematical model, the data collected fit an exponential relation of the type D/P = a(1-e-t/tau). The values of a and tau are unique for a given patient and were determined using a nonlinear regression technique. The formula performed well on our published data-the true and predicted 6-hr D/P Cr being 0.696 and 0.71, respectively. SETTING: The University Hospital and Clinics, Dalton Cardiovascular Research Center and Dialysis Clinic, Inc., Columbia, Missouri. PATIENTS: All CAPD patients on four 2-L exchanges/day at the time of the 24-hr collections were included. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Closeness of 4-hr and 6-hr D/P Cr values to those of 24-hr ratios. RESULTS: The study group comprised 74 patients (age, mean +/- SEM: 56.4 +/- 1.8 yr) with 80 PETs and 145 (24-hr) collections. The interval between the two tests was 8.3 +/- 0.9 months (0-48.7 months). The median 24-hr D/P Cr of 0.760 did not differ significantly from the predicted median 6-hr D/P Cr of 0.755. A subgroup analysis, based on transport type, showed that this relationship was most precise in the high-average transporters. The predicted 6-hr D/P Cr was within 10% of the 24-hr D/P Cr in 48% of patients and within 20% in 77% of patients. The margin of error was greatest in the low transporters. CONCLUSIONS: To conclude, the 4-hr D/P Cr from a PET cannot be used interchangeably with the D/P Cr in the 24-hr dialysate collections, hence, the clearances calculated thereof will be inaccurate. Using the proposed model, it is feasible to use the 4-hr PET results to obtain 5- and 6-hr D/P Cr values. In our study, using this model, the extrapolated 6-hr D/P Cr is similar to the D/P Cr in 24-hr dialysate collections only in the high-average transporters. Hence, the best way to determine clearances in peritoneal dialysis patients is still by collecting 24-hr dialysates.

Adult↗
PubMedDate not supplied

Toward targets for initiation of chronic dialysis.

OBJECTIVES: To better define the targets for initiation of chronic dialysis, we compared the relationship between the normalized protein equivalent of nitrogen appearance (nPNA, g/kg standard weight/day) and weekly urea clearance (Kt) normalized to total body water (V) in predialysis chronic renal failure (CRF) patients and in patients on continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD). We also studied the relationships of other nutritional parameters to weekly Kt/Vurea in CRF patients. DESIGN: This cross-sectional study was a prospective observational design meant to study each patient once. SETTING: The University Hospital and Clinics and Harry S. Truman VA Medical Center, Columbia, Missouri. PATIENTS: Forty-five consecutive predialysis CRF patients were enrolled and the results compared with patients on CAPD and HD. RESULTS: In CRF, the nPNA calculated from urea appearance correlated with the weekly Kt/Vurea (r = 0.57, p < 0.0001) and, using exponential best-fit, nPNA = 1.217 x (1-e-0.769Kt/V). This exponential relationship was similar to that for CAPD and both were different from that in patients on HD. Likewise, nPNAs, calculated from Kjeldahl nitrogen output, and weekly Kt/Vurea were correlated (r = 0.37, p = 0.014) and, using exponential best-fit, nPNA = 1.102(1-e-0.867Kt/V), similar to the relationship in patients on CAPD. Evidence is presented that these relationships are not explained only by mathematical coupling. There was a significant correlation between the weekly Kt/Vurea and 24-hour urinary creatinine excretion. CONCLUSIONS: The findings suggest that in CRF, as in CAPD, a weekly Kt/Vurea less than 2.0 is likely to be associated with a nPNA less than 0.9 g/kg standard weight. In CRF patients, initiation of chronic dialysis should be considered if weekly renal Kt/Vurea falls below 2.0 and a nPNA greater than 0.8 is desired.

Adult↗
PubMedDate not supplied

1996 Peritoneal Dialysis Core Indicators Study: report on nutritional indicators.

OBJECTIVE: The 1996 Peritoneal Dialysis Core Indicators Study illustrates the conduct of peritoneal dialysis in the United States during 1996. DESIGN AND PATIENT POPULATION: The survey is a medical records audit of 1317 randomly selected adult U.S.A. Medicare patients using peritoneal dialysis during 1996. OUTCOME MEASURES: Abstracted data included basic demographic characteristics, dialysis prescription, delivered dialysis dose, residual renal function, serum albumin, hematocrit, anemia management, and patient status. RESULTS: The survey included 785 patients using continuous ambulatory peritoneal dialysis (CAPD) and 423 using automated peritoneal dialysis (APD) primarily in the form of continuous cycling peritoneal dialysis (CCPD). Except for the prescription mechanics and a greater likelihood that African-Americans would use CAPD, the groups did not differ substantially from one another. Evaluation of patient weight (W), body mass index (BMI), residual renal function, average serum albumin, protein equivalent of nitrogen appearance (nPNA), and dialysis efficiency as weekly fractional urea nitrogen removal (wKt/Vurea) and weekly creatinine clearance (wCrCl) revealed a picture of reasonable dialysis delivery and marginal protein nutrition. Additionally, there was little evidence that "dialysis efficiency," over the range assessed, had a major influence on nutritional status. Despite a tendency toward obesity (body weight = 76.6+/-20.0 kg and BMI = 27+/-7), 47% of patients had an average serum albumin below"normal" (3.5 g/dL by bromcresol green) and 70% had a nPNA below 1.0 g/kg/day. CONCLUSIONS: Peritoneal dialysis patients appear to have marginal protein reserves despite surfeit energy stores.

Adult↗
PubMedDate not supplied

Six-year experience with Swan neck presternal peritoneal dialysis catheter.

BACKGROUND: The presternal peritoneal catheter is composed of two silicone rubber tubes joined by a titanium connector at the time of implantation, and has an exit on the chest. OBJECTIVE: Comparison of survival and complication rates of Swan neck abdominal catheters with those of the presternal catheter. DESIGN: Nonrandomized study with prospective collection of data between August 1991 and October 1997. SETTING: Tertiary referral center. PATIENTS: In 57 patients, 58 presternal catheters and, in 81 patients, 86 abdominal catheters were implanted. Patients chose the type of catheter; however, obese individuals and those with ostomies and previous catheter problems were encouraged to opt for the presternal catheter. Others chose the presternal catheter in order to take tub baths or use a whirlpool. MAIN OUTCOME MEASURES: Life-table analyses of catheter survival censored for transplant, transfer, and death; reasons for catheter removal due to complications; and patient satisfaction. RESULTS: Two-year survival probabilities were 0.95 and 0.75 for presternal and abdominal catheters, respectively. Nine abdominal catheters were removed due to exit/tunnel infections (including five with peritonitis), and four due to peritonitis. External cuff shaving in four presternal catheters has extended survival for more than 1 year. Four presternal catheters were removed due to peritonitis. No catheters in either group were lost due to leakage or obstruction. The peritonitis rate was 1 episode per 37.4 patient-months and 1/20.5 patient-months for presternal and abdominal catheters, respectively. These differences are not significant. Patient acceptance of the presternal catheters was excellent; in the latest period, from January to October 1997, presternal catheters were chosen by 15/24 patients. CONCLUSIONS: The trend to improved outcomes in presternal catheters continues to validate the rationale for presternal catheter design. Decreased frequency of exit/tunnel infection may be due to more effective immobilization on the chest, less trauma, and avoidance of submersion in stagnant water. No specific contraindications to use of the presternal catheter have been identified.

Bacterial Infections↗