Significant reduction of peritonitis rate by the use of Twin-bag system in a Canadian regional CAPD program.

In a regional CAPD program in Northern Alberta, Canada, the peritonitis rates among patients undergoing CAPD treatment were quite high: 1/8.3 and 1/7.4 per patient month from a population of 75 and 76 patients in 1989 and 1990 respectively. Our patient population is comprised of different ethnic groups, separated widely from the dialysis centre; over half of them are above the age of 60 years. As it is not possible to change the patient characteristics in our centre, we switched to the Twin-bag disconnect system in 83 out of a total of 103 patients in 1991. With this change our overall peritonitis rate has significantly improved to 1/14 per patient months and 1/17 per patient months in patients using the Twin-bag system. This improvement in the peritonitis rate has occurred without any change in our patient characteristics. We find the improvement in our peritonitis rate is due to the use of the new Twin-bag system, which provides total disconnection with no spikes and thereby reduces peritonitis due to touch contamination.

An extracorporeal model of biofilm-adherent bacterial microcolony colonization for the study of peritonitis in continuous ambulatory peritoneal dialysis.

We have developed an extracorporeal system for investigating in vitro the biofilm-adherent bacterial microcolonies (BABM) that grow on Tenckhoff catheters (TC), to study peritonitis in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). A modified Robbins' device, attached to sampling plugs with TC discs and connected to the dialysate via a peristaltic pump, is run for 24 h; scrapings from pairs of TC discs are processed for assessment of viable BABM, one of each pair for culture by routine microbiology techniques and the other for examination by scanning and transmission electron microscopy (EM). No colonization was noted with fresh dialysis solutions and spent dialysates from patients without clinical peritonits; but, when bacterial suspensions were added to aliquots of the same dialysates, BABM were noted on both culture and EM. In a study of 4 patients on CAPD treatment, who had clinically evident peritonitis, routine cultures of spent dialysate were positive in only 2, but BABM were found in cultures and EM preparations of disc scrapings in all 4 cases. We conclude from these preliminary findings that this extracorporeal system is reliable, and well suited for studying the role of BABM in CAPD-associated peritonitis in vitro.

Comparison of hemodialysis and hypertonic hemodiafiltration on cardiac function [corrected].

This study compared the acute and chronic effects on cardiac function of treatment with hypertonic hemodiafiltration (H HDF) and hemodialysis (HD). Cardiac function was assessed before, during and after a run of H HDF and HD using echocardiography and impedance cardiography in 10 patients in a randomized cross-over sequence, two months after stabilization on each treatment. Blood biochemistry was performed before and after each run. Ejection fraction and fractional shortening were significantly higher before the H HDF run, compared to the HD run, and this difference persisted during and after the treatment runs (both P less than 0.05). There was a corresponding significant difference in the increase of the velocity of circumferential fiber shortening and in the reduction of end systolic diameter during and after H HDF (P less than 0.05). Heart rate, stroke volume, cardiac output, systemic vascular resistance and mean arterial pressure did not differ significantly between the two treatments. Plasma calcium and bicarbonate were significantly higher (P less than 0.03) at the start of H HDF and this difference was enhanced at the end of the run. In conclusion, H HDF compared with HD, is associated with a better myocardial function in both the short and long term treatments. The evidence suggests that this may be due to improved levels of plasma calcium, bicarbonate, and/or the removal of an as yet unidentified myocardial toxin.

The effects of dialysis on brain water and EEG in stable chronic uremia.

Cerebral edema in uremic animals and humans, as well as an EEG deterioration in humans, has been reported after dialysis. Both are manifestations of the dialysis disequilibrium syndrome (DDS). This study was designed to analyze the changes induced by dialysis in the EEG pattern (spectral analysis), in the cerebral hydration, and ventricular size (computed tomography [CT] of the brain) in a group of 11 stable uremic patients. They volunteered for a randomized crossover study of 4 months each of standard hemodialysis (HD) and hypertonic hemodiafiltration (H HDF). H HDF is a dialysis technique that is shorter and more efficient than HD. An EEG recording, a CT scan of the brain, and blood biochemistry were performed before and after a HD (four hours, blood flow rate 250 mL/min) and a H HDF run (three hours, blood flow rate 400 mL/min). Approximately 6 weeks of stabilization on each treatment were allowed before these studies. No difference was found in the density of seven specific brain structures (base and apical cuts), when comparing pre- v post-HD, pre- v post-H HDF, pre- HD v pre-H HDF, and post-HD v post-H HDF. Furthermore, no difference was evident either in the bicaudate diameter of the lateral ventricles or in the transverse diameter of the third ventricle. In addition, no significant in-between- and within-treatment difference was observed when analyzing the EEG% power (3-7/7-13 Hz) data. In conclusion, this study shows neither a postdialysis change in brain density and ventricular size nor a postdialysis EEG deterioration in a group of stable uremic patients undergoing both a rapid and a standard dialysis treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma volume changes induced by hypertonic hemodiafiltration and standard hemodialysis.

We have previously reported that treatment of uremia by hypertonic hemodiafiltration (H-HDF) results in a more stable hemodynamic response as compared to standard hemodialysis (HD). The purpose of this study was to determine if plasma volume (PV) preservation was a significant factor in this response. Nine patients were studied during single treatment sessions of H-HDF and HD. Both sessions were 3 h in duration and the ultrafiltration rate and volume were matched. 10 microCi of 125I human serum albumin were injected 40 min before each session for measurement of PV. Changes in PV during the session were determined from the change in plasma albumin concentration and the hematocrit. The decrease in PV was significantly less during H-HDF. This was associated with a significantly higher plasma sodium and osmolality. The calculated effective osmolality during H-HDF was not only higher than in HD, but showed a significant increase at 2 and 3 h when compared to the baseline level (p less than 0.05). The calculated volume of extravascular mobilization was higher during H-HDF and is probably the mechanism of the PV preservation. In conclusion, this study demonstrates that PV is preserved during H-HDF better than during HD as a result of a more adequate plasma refilling; this appears to be mediated by an increased plasma effective osmolality.

Predentin changes in patients with chronic renal failure.

Morphometric studies were carried out on teeth extracted from normal human patients and compared with those extracted from patients suffering from chronic renal failure and patients being treated by chronic hemodialysis. The findings revealed that the predentin layer in patients suffering from chronic renal failure and patients undergoing chronic hemodialysis was significantly thicker than normal. These findings suggest that predentin is the metabolic equivalent of osteoid in bone and that increases in the predentin thickness may therefore be a reliable indicator of osteomalacia. It is suggested that the term odontomalacia be used to describe the changes occurring in the dentin of these patients.

CT findings in postpartum renal cortical necrosis.

A 34-year-old woman presented with postpartum renal cortical necrosis. Contrast-enhanced computerized tomography (CT) of her kidneys showed a narrow subcapsular band of increased density that was separated from the medulla by a distinct band of decreased density. This is analogous to the decreased cortical nephrogram seen on arteriography. The CT scan may be a useful, non-invasive diagnostic procedure in renal cortical necrosis.

Cyclosporin A: a powerful immunosuppressant.

Cyclosporin A (CyA) is a powerful immunosuppressive agent whose lack of myelotoxicity makes it unique among nonsteroidal drugs currently given for immunosuppression. It has been used with initial success in recipients of kidney, liver, bone marrow and pancreas transplants, and it may also have clinical application in the treatment of autoimmune disorders. In regard to its use in transplant recipients, there are many remaining questions about its mechanism of action, the optimum dose, whether it should be used alone or with other immunosuppressants, whether it can suppress chronic rejection and what its long-term side effects may be. These questions can only be answered by further careful laboratory investigation and controlled clinical trials. Until then, CyA should only be administered in centres experienced in its use.

Chronic plasma exchange therapy in SLE nephritis.

Eight patients who met the clinical, immunological and renal morphologic criteria for systemic lupus erythematosus with diffuse proliferative nephritis were plasma exchanged on a monthly basis for a total of 119 months. Renal function, episodes of disease activity, hospitalizations, frequency of immunological abnormalities, and monthly quantity of steroid and azathioprine therapy were compared with their course up to one year prior to the onset of the plasma exchange program. The changes noted in these parameters indicate that chronic plasma exchange therapy is safe, may be beneficial and requires controlled prospective study to determine the role in the treatment of patients with systemic lupus erythematosus and diffuse proliferative glomerulonephritis.

Percutaneous transluminal dilatation of transplant renal artery stenosis.

Percutaneous transluminal angioplasty has been applied to the treatment of transplant renal artery stenosis in 3 patients, 2 with severe hypertension resistant to medical therapy, and one with graft dysfunction related to the presence of the stenosis in the early post-transplant period. The clinical courses of the patients before and after angioplasty are illustrated and the usefulness of the technique in this difficult situation stressed.

Immunological and pharmacological monitoring in the clinical use of cyclosporin A.

Immunological reactivity to donor antigens and serum concentrations of cyclosporin A were monitored in six patients after renal transplantation. At concentrations of 0.1--1.0 microgram/ml cyclosporin A prevented both donor-specific immune reactivity and clinical rejection during the early post-transplant course. Measurement of cyclosporin A levels and immunological indices allowed individual adjustment of the dosage so as to give excellent early graft function with few adverse effects.