The arteriovenous fistula (AVF) has been a mainstay of hemodialysis treatments and the preferred access route since its inception in the 1960s, due to its longevity and resistance to infection. However, the AVF is not benign. There is significant primary failure, as well as cardiac, vascular, and other, less well recognized, complications. Together, they represent toxicity, to which considerable morbidity and mortality can be attached. Official policy, based on guidelines where AVF toxicity is given short shrift, drives an increase in use of these devices, and may have undesired consequences.

Laparoscopic revision is a successful technique for salvage of occluded peritoneal catheters.

Dual X-ray absorptiometry is the standard diagnostic modality for identification of low bone mineral density, a finding which is in the general population usually indicative of osteopenia or osteoporosis. However, chronic kidney disease (CKD) patients diagnosed with osteopenia or osteoporosis may in actual fact have renal osteodystrophy with high or low bone turnover. While bisphosphonates are currently prescribed for the prevention of fractures in osteoporosis and high-risk osteopenic patients, the clinical utility of bisphosphonate therapy in CKD has not been established. Furthermore, bisphosphonates accumulate in bone, inhibit osteoclasts, and may cause or exacerbate low-turnover (adynamic) bone disease – particularly in patients presenting with low parathyroid hormone (PTH) levels or receiving treatment for secondary hyperparathyroidism. Bone biopsy with non-decalcified histopathology remains the gold standard for the identification and evaluation of bone disorders, including osteoporosis and renal osteodystrophy. Thirteen CKD patients (stage II–IV), referred to our clinic over a 12-month period, were identified as having taken bisphosphonates from 4 to >60 months after a diagnosis of osteopenia or osteoporosis. All patients underwent biopsies of trabecular bone from the iliac crest following oral administration of time-separated doses of doxycycline and tetracycline. Bone pathology was assessed after processing for mineralized histology. For all patients, clinical data collection included assessment of likely causes of kidney disease, MDRD glomerular filtration rate, calcium-phosphate product, intact PTH level, alkaline phosphatase, and bisphosphonate exposure. All 13 patients were diagnosed with adynamic bone on biopsy evaluation. Eleven biopsies revealed decreased cancellous bone mass; 8 showed decreased osteoid surface; 8 disclosed decreased osteoid thickness, and all 13 demonstrated low or low-normal osteoclast/osteoblast interface. Assessment of dynamic bone formation demonstrated decreased or absent single- or double-labeled osteoid in all 13 bone specimens. Based on these observations, the use of bisphosphonates in CKD cannot be recommended.

Continuous flow peritoneal dialysis (CFPD) is a technique of renal replacement therapy (RRT) dating back to the 1960s. Its essential features are a fixed intraperitoneal volume and rapid, continuous movement of dialysis solution into and out of the peritoneal cavity. Inlet and outlet catheters and a means of generating a large volume of sterile dialysate are required. External regeneration of dialysate via conventional hemodialysis (HD) equipment or sorbent technology mitigates the need for large volumes of sterile fluid and makes the technique feasible. Clearance depends on the peritoneal mass transfer coefficient, rate of dialysate flow, and efficiency of external regeneration. Studies to date all demonstrate small solute clearances three to eight times greater than conventional automated peritoneal dialysis (PD). Catheter design is crucial to the clinical success of the technique and will be discussed. Potential applications include daily home dialysis, treatment of acute renal failure in the intensive care unit (ICU), and ultrafiltration of ascites. Clinical experience with the latter will be presented in detail.

Peritoneal dialysis (PD) is still underutilized as home based renal replacement therapy and in-patient treatment of acute renal failure. Hindering the expansion of PD is poor solute clearance, which is a result of the intermittent dwell technique. Continuous flow PD is an old concept that has demonstrated urea clearances from 2-5 times higher than standard PD. It relies on a 2-3 l dwell volume and continuous dialysate flow at 100-300 ml/min. This high flow rate dictates the need for an efficient dual lumen catheter, or two separate catheters with ports separated maximally, as well as a means to generate or regenerate large volumes of fluid. A modified hemodialysis system can easily be adapted to regenerate sterile peritoneal dialysate, and a dual lumen catheter with excellent flow characteristics has been designed. Ultrafiltration control and a means to accurately balance transperitoneal with external ultrafiltration persist as technical challenges. Continuous flow PD remains an attractive modality for daily home dialysis and treatment of acute renal failure.

Concern over the inherent inefficiency of solute removal by conventional peritoneal dialysis (PD) has led to renewed interest in continuous flow PD (CFPD). We present clinical data from two experiences with CFPD. In the first, two catheters were used to recirculate a fixed intraperitoneal volume through an external circuit comprised of a standard hemodialysis system. The second patient had a dual-lumen PD catheter and was studied during two sessions of flow-through PD (FTPD) using sterile PD solution. Urea clearances with both techniques were around 30 ml/min, which is consistent with data reported in the literature. Significant streaming of dialysate from port to port within the peritoneal cavity limited clearances. CFPD offers a potentially safe and effective alternative to daily or nightly home hemodialysis.

Patients with kidney failure and acute respiratory distress syndrome (ARDS) requiring prone position have not been candidates for peritoneal dialysis (PD) due to concern with increased intra-abdominal pressure, reduction in respiratory system compliance and risks of peritoneal fluid leaks. We describe our experience in delivering acute PD during the surge in Covid-19 acute kidney injury (AKI) in the subset of patients requiring prone positioning. All seven patients included in this report were admitted to the intensive care unit with SARS-CoV-2 infection leading to ARDS, AKI and multisystem organ failure. All required renal replacement therapy, and prone positioning to improve ventilation/perfusion mismatch. All seven were able to continue PD despite prone positioning without any detrimental effects on respiratory mechanics or the need to switch to a different modality. Fluid leakage was noted in 71% of patients, but mild and readily resolved. We were able to successfully implement acute PD in ventilator-dependent prone patients suffering from Covid-19-related AKI. This required a team effort and some modifications in the conventional PD prescription and delivery.

Continuous flow peritoneal dialysis (CFPD) is a technique of renal replacement therapy (RRT) dating back to the 1950s. Its essential features are a fixed intraperitoneal volume and rapid, continuous movement of dialysis solution into and out of the peritoneal cavity. Inlet and outlet catheters and a means of generating a large volume of sterile dialysate are required. External regeneration of dialysate via conventional hemodialysis equipment or sorbent technology mitigates the need for large volumes of sterile fluid and makes the technique feasible. Clearance depends on peritoneal mass transfer coefficient, rate of dialysate flow and efficiency of external regeneration. Studies to date all demonstrate small solute clearances 3-8 times greater than conventional automated peritoneal dialysis (APD). Catheter design is crucial to the clinical success of the technique and will be discussed. Potential applications include daily home dialysis, treatment of acute renal failure in the ICU, ultrafiltration of ascites, and the wearable artificial kidney.