The Peritoneal Membrane and Its Role in Peritoneal Dialysis

Comparison of Bupivacaine Trocar Site Infiltration and Peritoneal Instillation for Postoperative Pain in Pediatric Laparoscopic Surgery

Background Laparoscopic surgery has become the treatment of choice for pediatric patients due to its numerous advantages over open surgery. However, postoperative pain remains a significant barrier to rapid recovery. The intraperitoneal use of local anesthetics for pain management is underutilized in the pediatric population. This study aimed to compare the effectiveness of bupivacaine administered at the trocar site versus in the peritoneal cavity for managing postoperative pain in pediatric laparoscopic surgery. Methodology This quasi-experimental study was conducted in the Department of Pediatric Surgery at the Combined Military Hospital, Lahore. A total of 80 patients who underwent laparoscopic surgery were divided into two groups of 40 each. The W Group received bupivacaine trocar site infiltration, while the P Group received intraperitoneal bupivacaine instillation at the end of surgery. Pain scores were recorded in both groups at one, two, four, six, and eight hours postoperatively. The need for rescue analgesia and the incidence of shoulder pain were also evaluated as secondary outcomes in both groups. Results The mean pain score was 19.15 ± 3.8 in the W group, compared to 17.30 ± 4.0 in the P group, with a calculated p-value of 0.03, indicating a significant difference between the two groups. Similarly, interval pain scores, the need for rescue analgesia, and the incidence of shoulder pain were significantly lower in the P group compared to the W group. Conclusion We concluded that intraperitoneal instillation of bupivacaine is more effective than trocar site infiltration with the same agent in reducing postoperative pain across various pediatric laparoscopic procedures. This approach should be adopted to maximize the benefits of minimally invasive surgery in the pediatric population.

The relationship between changes in peritoneal membrane solute transfer characteristics and cardiac remodeling in patients with peritoneal dialysis

INTRODUCTION

We aimed to determine the relationship between the dilatation of the heart chambers and the change in peritoneal membrane solute transfer characteristics (PMTC) in long-term peritoneal dialysis (PD) patients.

METHODS

This is a retrospective, single-center study including the follow-up of maintenance PD patients. According to the changes in PMTC from baseline to the last visit, patients were divided into three groups; stable (n = 11), increased (n = 41), and decreased transporters (n = 35).

RESULTS

Left atrium (LA) and Right ventricle (RV) dilatation were more prominent in the PMTC-decreased group compared to PMTC-increased and stable groups (p < 0.001 and p = 0.07, respectively). The Cox regression analysis showed that only decreased PMTC was associated with LA dilatation (HR 2.89 [CI 95%1.54, 5.45] p < 0.01) and RV dilatation (HR 3.01 [CI 95%1.40, 6.21] p < 0.01).

CONCLUSION

PD can be associated with unfavorable dynamic changes in cardiac structure and functions even at the subclinical level.

Intraperitoneal MASP-1 Levels are Associated with Peritoneal Solute Transport Rate in Peritoneal Dialysis Patients: A Retrospective Cohort Study

Purpose

A major limitation of long-term peritoneal dialysis (PD) is peritoneal membrane dysfunction characterized by faster peritoneal solute-transport rate (PSTR). This study aimed to identify efficient complement factors in peritoneal effluents of continuous ambulatory peritoneal dialysis (CAPD) patients that can predict the PSTR.

Methods

A multiplex suspension protein array was used to screened related complement pathways in overnight peritoneal effluents among 58 CAPD patients. Then the related complement factors in lectin and classical pathways in effluents were analyzed using ELISA kits among another cohort of 129 CAPD patients. Logistic regression modeling was fitted to predict the PSTR of PD patients.

Results

The multiplex suspension protein array showed complement factors including C2, C4b, C5, C5a, Factor D, Factor I, and MBL were detected in effluents of CAPD patients, and the effluent C2 Appearance rate (Ar) and C4b Ar levels were significantly correlated with D/P Cr and D/D0 glucose. The levels of effluents MASP-1 Ar, M-Ficolin Ar, C2 Ar and C4b Ar, which belong to the lectin pathway were also positively correlated with D/P Cr according the ELISA results and these parameters were expressed higher in the high and high-average (H/HA) groups according to the PET results. Moreover, effluent Masp-1 was independently associated with increased PSTR and adverse events related peritoneal transport function failure.

Conclusion

This study suggested that the lectin pathway may be involved in local complement activation and peritoneal injury of PD patients, intraperitoneal level of Masp-1 was an independent predictor of increased PSTR in PD patients.

Aryl Hydrocarbon Receptor Pathway Augments Peritoneal Fibrosis in a Murine CKD Model Exposed to Peritoneal Dialysate

Key Points

CKD and high glucose–containing peritoneal dialysate alter peritoneal membrane contributing to peritoneal dialysis failure, with a poorly understood mechanism. CKD milieu activates the aryl hydrocarbon receptor pathway in the subperitoneal vasculature, increasing the peritoneal fibrosis and collagen deposition in humans and mice. An aryl hydrocarbon receptor inhibitor mitigates CKD and peritoneal dialysis–mediated peritoneal fibrosis, collagen deposition, and vasculogenesis in a mouse model.

Background

CKD is a proinflammatory and profibrotic condition and can independently alter the peritoneal membrane structure. Peritoneal dialysis (PD) results in profound alterations in the peritoneal membrane. The mechanisms contributing to the alterations of the peritoneal membrane structure in CKD milieu, along with PD, are poorly understood.

Methods

Here, we show that human CKD induces peritoneal membrane thickening, fibrosis, and collagen deposition and activates the aryl hydrocarbon receptor (AHR) pathway in the subperitoneal vasculature. Leveraging a novel model of PD in CKD mice, we confirm these CKD-induced changes in the peritoneal membrane, which are exacerbated on exposure to the peritoneal dialysate. Peritoneal dialysate further augmented the AHR activity in endothelial cells of peritoneal microvasculature in CKD mice.

Results

Treatment of CKD mice with an AHR inhibitor in peritoneal dialysate for 2 weeks resulted in a seven-fold reduction in AHR expression in the endothelial cells of subperitoneal capillaries, a five-fold decrease in subperitoneal space, and a nine-fold decrease in fibrosis and collagen deposition compared with vehicle-treated CKD mice. AHR inhibition reduced inflammation, subperitoneal neovascular areas, and its downstream target, tissue factor. The AHR inhibitor treatment normalized the peritoneal dialysate-induced proinflammatory and profibrotic cytokines, such as IL-6, monocyte chemoattractant protein-1, and macrophage inflammatory protein 1 levels, in CKD mice.

Conclusions

This study uncovers the activation of the AHR-cytokine axis in the endothelial cells of subperitoneal vessels in humans and mice with CKD, which is likely to prime the peritoneal membrane to peritoneal dialysate–mediated alterations. This study supports further exploration of AHR as a potential therapeutic target to preserve the structural and functional integrity of the peritoneal membrane in PD.

Can one long peritoneal dwell with icodextrin replace two short dwells with glucose?

Background

Due to the slower dissipation of the osmotic gradient, icodextrin-based solutions, compared to glucose-based solutions, can improve water removal. We investigated scenarios where one icodextrin-based long dwell (Extraneal) replaced two glucose-based exchanges.

Methods

The three-pore model with icodextrin hydrolysis was used for numerical simulations of a single exchange to investigate the impact of different peritoneal dialysis schedules on fluid and solute removal in patients with different peritoneal solute transfer rates (PSTRs). We evaluated water removal (ultrafiltration, UF), absorbed mass of glucose (AbsGluc) and carbohydrates (AbsCHO, for glucose and glucose polymers), ultrafiltration efficiency (UFE = UF/AbsCHO) per exchange, and specified dwell time, and removed solute mass for sodium (ReNa), urea (ReU), and creatinine (ReCr) for a single peritoneal exchange with 7.5% icodextrin (Extraneal®) and glucose-based solutions (1.36% and 2.27%) and various dwell durations in patients with fast and average PSTRs.

Results

Introducing 7.5% icodextrin for the long dwell to replace one of three or four glucose-based exchanges per day leads to increased fluid and solute removal and higher UF efficiency for studied transport groups. Replacing two glucose-based exchanges with one icodextrin exchange provides higher or similar water removal and higher daily sodium removal but slightly lower daily removal of urea and creatinine, irrespective of the transport type present in the case of reference prescription with three and four daily exchanges.

Conclusion

One 7.5% icodextrin can replace two glucose solutions. Unlike glucose-based solutions, it resulted only in minor differences between PSTR groups in terms of water and solute removal with UFE remaining stable up to 16 h.