Sleep apnea in ESRD patients on HD and CAPD.
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Adult↗
Biomedical subjects
M D Hallett
Publications and source records attributed to M D Hallett.
Vaccination for prevention of CAPD associated staphylococcal infection: results of a prospective multicentre clinical trial.
124 stable CAPD patients from 8 Australian and 3 New Zealand centers were randomly assigned in a blinded fashion to one of two groups to study the effect of vaccination using commercial preparations consisting of a combined staphylococcus toxoid and whole killed staphylococci (SB) or normal saline solution (SS) on the incidence of peritonitis and exit site infection and S. aureus nasal carriage over a 12-month prospective period. In addition, levels of IgG, IgA, IgM, C3 and C4 were monitored during the trial period in serum and dialysate; serum levels of anti-alpha hemolysin and dialysate levels of fibronectin and specific antistaphylococcal antibodies were also measured. Over the period, treatment with SB or SS did not affect the incidence of peritonitis, catheter-related infection or S. aureus nasal carriage. However, vaccination with SB elicited a significant increase in the level of serum anti-alpha hemolysin throughout the 12 month duration of the study, although the level of increase was unrelated to the subsequent rate of peritonitis. Vaccination with SB but not SS elicited a significant increase in the dialysate level of specific antibodies against S. aureus. Serum levels of IgG, IgA, IgM, complement C3 and C4 were within the normal range in the CAPD patients studied and remained unaffected by vaccination with SB. In addition, dialysate levels of IgG, IgA, IgM, complement C3 and C4 were 50-100 times lower than corresponding serum levels and remained unaffected by vaccination. In summary, immunisation with an anti-staphylococcal agent was not successful in reducing peritonitis or exit site infection in CAPD patients.
Catheters, Indwelling↗
Long-term continuous ambulatory peritoneal dialysis. Mass transfer and nutritional and metabolic stability.
Long-term mass transfer and nutritional and metabolic stability of end-stage renal disease patients maintained on continuous ambulatory peritoneal dialysis (CAPD) continue to be of concern. This study longitudinally monitored 43 Japanese CAPD patients (29 males, 14 females) from three centres within the Tokyo Metropolitan Area for an average period of 15 +/- (SD) 8 months. The mean time for patients on CAPD at study initiation was 18 +/- 15 months. Monitored parameters included urea and creatinine mass transfer coefficients, clearances and blood levels, ultrafiltration, lipid levels, dietary protein intake, and weight. Lipid data were also gathered retrospectively from patient records from the time of CAPD initiation. The results were analyzed using regression growth curve analysis and analysis of variance. Statistically significant linear rises with time were apparent only for the creatinine mass transfer coefficients, although this was not considered clinically significant in terms of changes either in peritoneal creatinine clearances or ultrafiltration. Serum cholesterol levels were found to rise significantly above pre-dialysis levels 11 months after CAPD onset, thereafter returning to levels not significantly above baseline levels. In summary, CAPD provided stable, acceptable treatment over the study period.
Adult↗
Is the peritoneal membrane durable indefinitely?
In general, the permeability characteristics of the peritoneal membrane are well maintained with time in the context of current technique survival rates. Some data would suggest that there is a tendency toward hyperpermeability in long-term PD patients; in a much smaller group of patients this may manifest itself as a loss in ultrafiltration capacity in the short term, that is within 2-4 years after CAPD initiation. A reduction in factors, which continue to have a significant negative effect upon technique survival, such as peritonitis and catheter-related infection will see patients remaining on the therapy for longer. This may place a sharper focus on ultrafiltration loss in the PD population, particularly that associated with increases in the permeability of the peritoneum. However, until such time as significant improvements occur it is likely the peritoneal membrane will continue to be more durable than the therapy in the vast majority of patients. It is now becoming clearer that the rate of decline of residual renal function (RRF) may be an important factor in the development of sequelae associated with inadequate dialysis. The role of RRF has often been overlooked when the clinical manifestations of inadequate UF and solute removal have become apparent and further study is required to determine the contribution of residual diuresis to the table of prognostic factors associated with long-term stability of the PD patient. Nevertheless, it is clearly an important parameter worthy of considerable future focus. Although membrane performance appears well maintained in general, routine monitoring of the mass transfer performance of the peritoneum should be performed. Assessment will facilitate focussed dialytic management and allow the clinician to recognise and pre-empt potential problems resulting from inadequate dialysis associated with decreasing or increasing membrane permeability in the small number of patients so affected: such monitoring should include measurement of the mass transfer coefficient at onset and every 6-12 months thereafter. However, the monitoring of RRF and overall solute clearance is perhaps of more significance in view of the contribution of RRF to overall dialytic prescription. The routine assessment of these parameters is also encouraged.
Biological Transport↗
The role of lymphatic drainage in peritoneal mass transfer.
Peritoneal lymphatic drainage has recently been shown to be a contributing factor to both clearance and fluid removal patterns during continuous ambulatory peritoneal dialysis. In this report peritoneal transport equations are derived and compared and contrasted with existing models that ignore this term. It was found that for solutes for which the sieving coefficient may be assumed to equal unity, such as urea and creatinine, the values of the mass transfer area coefficient (KoA) are overestimated by the value of the lymphatic drainage rate. In this instance, corrected KoA may be obtained simply by subtracting lymphatic flow rate from the KoA calculated by traditional methods. For larger solutes, such as beta 2-microglobulin, for which the sieving coefficient may be assumed to equal zero, the value of mass transfer coefficient was underestimated to varying degrees; however, for values of lymphatic drainage rate less than 60 ml/h the effect will not be clinically measurable. A theoretical model is used to plot the dependence of net fluid removal on peritoneal lymphatic flow, glucose KoA, and hydraulic permeability. Reduction in net ultrafiltered volume, and hence estimation of transperitoneal ultrafiltration, is directly proportional to accumulated lymphatic drainage.
Creatinine↗
Loss of ultrafiltration in continuous ambulatory peritoneal dialysis (CAPD).
Fifteen patients on long-term continuous ambulatory peritoneal dialysis (CAPD) were assessed with respect to net ultrafiltration capacity. Eight patients were defined as having good and seven as having poor ultrafiltration on the basis of net ultrafiltrate obtained/mmol glucose infused. Subsequently, dialysate was sampled at times 0, 1, 15, 30, 60, 90, 120, 180, and 240 min. No difference in residual volume was observed between the groups. A significantly greater decrease in dialysate sodium during the initial dialysis period in those patients with good as compared to those with poor ultrafiltration occurred, reflecting a greater transcapillary movement of electrolyte poor ultrafiltrate. In those with good ultrafiltration, glucose transfer was normal in five and rapid in three, suggesting the latter had low rates of lymphatic reabsorption. Five of seven patients with poor ultrafiltration had no fall in dialysate sodium in association with a high rate of glucose transfer, suggesting a low rate of transcapillary water movement and normal to high lymphatic absorption. Two patients with low ultrafiltration had an initial fall in dialysate sodium with a normal glucose transfer and thus net ultrafiltration is low due to elevated lymphatic reabsorption. We thus propose that the relative contribution of transcapillary water movement and lymphatic reabsorption can be determined by assessing net ultrafiltration and dialysate sodium concentration in conjunction with solute transfer.
Biological Transport↗
Evolution of transport theory in CAPD.
Current mathematical approaches describing solute and mass transfer during CAPD are based on a compartmental model, assuming the body and the peritoneal cavity to be different compartments and the peritoneal membrane to be a more or less complicated interface. Whereas simplified mathematical approaches may prove useful for routine clinical determination of mass transfer characteristics, more complex models may better serve developmental and theoretical purposes.
Biological Transport↗