Influence of the preceding exchange on peritoneal equilibration test results: a prospective study

Peritoneal equilibration testing: Your questions answered

The peritoneal equilibration test (PET), first described in 1987, is a semiquantitative assessment of peritoneal transfer characteristics in patients undergoing peritoneal dialysis. It is typically performed as a 4-h exchange using 2.27/2.5% dextrose dialysate with serial measurements of blood and dialysate creatinine, urea, and glucose concentrations. The percentage absorption of glucose and D/P creatinine ratio are used to determine peritoneal solute transfer rates. It is used to both help guide peritoneal dialysis prescriptions and to prognosticate. There are several derivative tests which have been described in the literature. In this review, we describe the original PET, the various iterations of the PET, the information gleaned, and the use in the setting of poor solute clearance and in the diagnosis of membrane dysfunction, and limitations of the PET.

Monitoring of the peritoneal membrane

Background. Indirect methods can be used to provide valuable information about peritoneal structure and function for the indirect analysis of peritoneal membrane. Methods. The focus of this paper will be on the commonly available tools for this purpose. First, the value and clinical relevance of CA125 as a marker of mesothelial cell mass in peritoneal effluent will be evaluated. Thereafter, monitoring the peritoneal membrane by using its properties to transport solutes and water will be discussed. Results. The data obtained can be useful for tailoring dialysis adequacy, analysis of clinical problems such as ultrafiltration failure or to predict the development of peritoneal sclerosis.

The role of tidal peritoneal dialysis in modern practice: A European perspective

Tidal peritoneal dialysis (TPD) has been introduced to optimize adequacy of peritoneal dialysis (PD). Early studies reported similar or even better small solute clearances with TPD than those achieved with continuous ambulatory peritoneal dialysis or continuous cyclic peritoneal dialysis. However, in many studies treatment volumes were much higher during TPD compared with other PD modalities. Based on current evidence, TPD provides no advantage of increased small solute clearances, middle molecule clearances, or peritoneal ultrafiltration as compared to non-tidal automated peritoneal dialysis (APD) when dialysate flow is kept constant. However, TPD reduces drainage pain and nightly alarms during cycler treatment. Tidal volume should be kept as high as possible in these patients, especially in those with low average peritoneal transport rates. Based on theoretical considerations and little evidence, TPD could provide better clearances than conventional APD when a very high dialysate flow (>or=5 l/h) is used. Such dialysate flow rates are not routinely prescribed in home APD patients. However, they may be interesting for in-center PD patients. One randomized crossover trial reported higher small solute clearances with TPD compared to non-tidal APD in patients with acute renal failure. TPD is also the preferred treatment modality in patients with ascites as it allows a controlled outflow of fluid from the peritoneal cavity. Newer treatment modalities, for example, continuous flow PD, may be interesting alternatives in an effort to increase efficacy of PD in the future. However, because such treatment regimens are expensive and elaborate they have not been established for routine use until now.

A preceding exchange with polyglucose versus glucose solution modifies peritoneal equilibration test results

The peritoneal equilibration test (PET) is an important tool for evaluating peritoneal membrane characteristics. The polyglucose icodextrin induces ultrafiltration caused by colloid osmosis through the small pores of the peritoneal membrane and therefore is especially effective during long dwell times. The main indications for polyglucose solutions are daytime dwells in patients on automated peritoneal dialysis and nighttime exchanges in continuous ambulatory peritoneal dialysis (CAPD) patients. In CAPD patients, PET is started immediately after the icodextrin exchange. Therefore, we performed two PETs in each of 15 CAPD patients. PET post-1.36% glucose was performed immediately after a preceding exchange with 2 L of 1.36% glucose dialysate solution (dwell time, 10 hours). PET postpolyglucose was started immediately after a preceding exchange with 2 L of 7.5% icodextrin solution (dwell time, 10 hours). The dialysate to plasma (D/P) ratio of creatinine, phosphate, and sodium during PET postpolyglucose was significantly greater than during PET post-1.36% glucose at 1, 2, 3, and 4 hours of dwell time. The quotient of dialysate glucose at 1, 2, and 4 hours of dwell time to dialysate glucose at 0 dwell time was significantly lower in PET postpolyglucose compared with PET post-1.36% glucose. In the case of creatinine, phosphate, and glucose, PET postpolyglucose curves tended to be steeper than those of PET post-1.36% glucose during the first hour of dwell time, whereas both curves were parallel between 1 and 4 hours of dwell time. The course of D/P ratio curves of urea nitrogen, protein, and albumin was nearly identical between PET postpolyglucose and PET post-1.36% glucose. In a subgroup of 5 patients, D/P ratios of creatinine and phosphate were also greater in PET postpolyglucose compared with PET performed after a long dwell with 2.27% glucose solution. Before a scheduled PET, CAPD patients using icodextrin solution during the nighttime should perform their nighttime exchange with conventional glucose solution.