Advanced Dialysis Techniques
Expert-defined terms from the Postgraduate Certificate in Renal Care (Part II) course at LearnUNI. Free to read, free to share, paired with a professional course.
Acute Peritoneal Dialysis (APD) #
Acute Peritoneal Dialysis (APD)
A rapid‑start modality that uses the peritoneum as a filter for patients with su… #
APD typically employs automated cyclers to deliver multiple exchanges over 24 hours. Example: A critically ill postoperative patient receives 8‑hour nocturnal cycles to manage fluid overload. Practical application includes use in intensive care units where vascular access is limited. Challenges involve maintaining sterile technique, controlling ultrafiltration volume, and monitoring for peritonitis, especially when exchanges are frequent.
Automated Peritoneal Dialysis (Automated PD) #
Automated Peritoneal Dialysis (Automated PD)
A technology‑driven form of peritoneal dialysis where a machine (cycler) perform… #
Example: A home‑based patient sets the cycler for 5 L of dialysate over 8 hours, reducing daytime treatment burden. It improves patient autonomy and quality of life. Challenges include machine malfunction, power outages, and the need for patient education on troubleshooting and data interpretation.
Bioimpedance Spectroscopy (BIS) #
Bioimpedance Spectroscopy (BIS)
A non‑invasive technique that measures body composition by applying alternating… #
In dialysis, BIS guides ultrafiltration targets by quantifying fluid overload. Example: A patient with refractory hypertension uses BIS readings to adjust weekly ultrafiltration volume. Practical application extends to tailoring individualized dry weight. Limitations include variability due to electrode placement, patient movement, and the need for calibrated devices.
Continuous Renal Replacement Therapy (CRRT) #
Continuous Renal Replacement Therapy (CRRT)
A set of extracorporeal therapies delivering slow, continuous solute and fluid r… #
Modalities include continuous venovenous hemofiltration (CVVH) and continuous venovenous hemodiafiltration (CVVHDF). Example: A septic shock patient receives CVVHDF at 30 mL/kg/h to maintain fluid balance and clear inflammatory mediators. Challenges involve anticoagulation management, circuit clotting, and high resource utilization.
Diffusive Clearance #
Diffusive Clearance
The process by which solutes move across a semi‑permeable membrane from higher t… #
In high‑flux hemodialysis, diffusive clearance efficiently removes small‑molecule uremic toxins (<500 Da). Example: Urea removal during a 4‑hour high‑flux session relies primarily on diffusion. Practical implication includes selecting appropriate dialyzer membrane to maximize diffusive efficiency. Challenges arise when targeting middle‑molecule clearance, which requires additional convective mechanisms.
Hemodiafiltration (HDF) #
Hemodiafiltration (HDF)
A hybrid modality combining diffusive and convective solute removal #
Replacement fluid is infused either pre‑ or post‑filter, augmenting ultrafiltration and enhancing middle‑molecule clearance. Example: Online HDF delivers 20 L replacement fluid per session, improving β2‑microglobulin elimination. Practical applications include treatment of patients with amyloidosis or persistent pruritus. Challenges involve ensuring ultrapure replacement fluid, managing higher blood flow rates, and monitoring for albumin loss.
High‑Flux Hemodialysis #
High‑Flux Hemodialysis
Uses dialyzers with larger pore sizes (≥20 kDa) to increase removal of middle‑si… #
Example: A patient on high‑flux treatment experiences reduced β2‑microglobulin levels, decreasing dialysis‑related amyloidosis risk. Practical benefits include better cardiovascular outcomes. Challenges comprise higher cost, need for careful ultrafiltration control to avoid excessive fluid removal, and potential loss of essential proteins if membrane integrity is compromised.
High‑Volume Hemofiltration (HVHF) #
High‑Volume Hemofiltration (HVHF)
An intensive convective technique delivering ultrafiltration rates >35 mL/kg/h,… #
Example: A patient with septic shock undergoes HVHF for 6 hours, aiming to clear cytokines and stabilize hemodynamics. Practical application extends to research on modulating immune response. Challenges include rapid electrolyte shifts, albumin depletion, and the requirement for high‑capacity replacement fluid supplies.
Integrated Dialysis Therapy (IDT) #
Integrated Dialysis Therapy (IDT)
A coordinated approach that blends multiple dialysis techniques (e #
G., Intermittent hemodialysis plus nightly peritoneal dialysis) to optimize solute control and fluid management. Example: A patient with residual renal function uses nocturnal home hemodialysis three times weekly and daytime CAPD exchanges, preserving kidney function longer. Practical applications focus on individualized treatment plans. Challenges involve scheduling, training for multiple modalities, and ensuring consistent vascular and peritoneal access care.
Kt/V #
Kt/V
A dimensionless index representing the ratio of dialyzer clearance (K) multiplie… #
Target values differ by modality (e.G., Kt/V ≥ 1.2 Per session for thrice‑weekly HD). Example: A patient’s monthly Kt/V is calculated using online clearance monitoring, confirming adequacy. Practical use includes dose adjustment and quality benchmarking. Challenges arise in accurately estimating V in obese patients and accounting for residual renal function.
Low‑Flux Hemodialysis #
Low‑Flux Hemodialysis
Employs membranes with smaller pore sizes (<10 kDa), primarily removing small so… #
Example: A standard maintenance dialysis unit uses low‑flux dialyzers for patients with minimal middle‑molecule burden. Practical benefits include lower cost and reduced albumin loss. Challenges involve limited efficacy for β2‑microglobulin and other middle‑size toxins, potentially contributing to long‑term complications.
Middle‑Molecule Clearance #
Middle‑Molecule Clearance
The removal of solutes ranging from 500 Da to 60 kDa, which are implicated in di… #
Example: An HDF regimen achieving convective volume >20 L per session significantly lowers β2‑microglobulin concentrations. Practical relevance includes improving patient symptomatology (e.G., Pruritus). Challenges include balancing convective volume with hemodynamic stability and preventing nutrient loss.
Nocturnal Hemodialysis (NHD) #
Nocturnal Hemodialysis (NHD)
A schedule where dialysis is performed overnight, typically 6‑8 hours, allowing… #
Example: A patient conducts three nocturnal sessions at home, achieving superior phosphate control and reduced antihypertensive medication. Practical advantages include better quality of life and flexibility. Challenges comprise ensuring patient safety during sleep, reliable home water treatment, and managing vascular access integrity.
Online Hemofiltration (OHF) #
Online Hemofiltration (OHF)
A technique where sterile, ultrapure replacement fluid is produced on‑demand by… #
Example: An OHF system delivers 25 L of replacement fluid during a single session, enhancing convective clearance. Practical use reduces logistical burden and storage requirements. Challenges involve strict water quality monitoring, maintenance of filtration membranes, and compliance with infection control standards.
Peritoneal Equilibration Test (PET) #
Peritoneal Equilibration Test (PET)
A diagnostic assessment measuring the rate of solute equilibration between dialy… #
Example: A PET result showing D/P creatinine = 0.78 Classifies the patient as a high transporter, prompting shorter dwells. Practical application guides prescription of exchange volumes and dwell times. Challenges include variability due to inflammation, glucose concentration, and patient adherence to test protocol.
Peritoneal Dialysis Fluid (PDF) #
Peritoneal Dialysis Fluid (PDF)
A sterile solution containing electrolytes, buffer, and an osmotic agent (common… #
Example: A 2.5 % Glucose PDF is selected for a patient requiring higher ultrafiltration. Practical considerations involve selecting appropriate osmotic agents to minimize peritoneal membrane damage. Challenges include glucose‑induced angiogenesis, metabolic derangements, and long‑term membrane fibrosis.
Peritoneal Membrane Transport Characteristics #
Peritoneal Membrane Transport Characteristics
The intrinsic ability of the peritoneal capillary network to allow solute and wa… #
Example: A low‑transport patient benefits from longer dwell times to achieve adequate solute clearance. Practical application includes tailoring exchange regimens. Challenges consist of transport status shifting over time, requiring periodic reassessment.
Renal Replacement Therapy (RRT) Modality Selection #
Renal Replacement Therapy (RRT) Modality Selection
The process of choosing the optimal dialysis technique (hemodialysis, peritoneal… #
Example: A young, employed patient with residual renal function may be steered toward home nocturnal hemodialysis. Practical impact includes improving adherence and outcomes. Challenges involve equitable access to technology, insurance coverage, and patient education.
Sorbent Dialysis (Hemodialysis with Sorbent Cartridge) #
Sorbent Dialysis (Hemodialysis with Sorbent Cartridge)
A modality that incorporates sorbent materials (e #
G., Activated charcoal, resin) within the circuit to bind protein‑bound and middle‑size toxins beyond membrane filtration. Example: A portable sorbent‑based system used in remote settings reduces uremic symptoms during travel. Practical benefits include reduced need for large dialyzers and water supply. Challenges encompass cartridge saturation, limited clearance of electrolytes, and cost of consumables.
Therapeutic Plasma Exchange (TPE) #
Therapeutic Plasma Exchange (TPE)
A procedure where plasma is removed and replaced with albumin or fresh frozen pl… #
Example: A patient with anti‑GBM disease undergoes daily TPE alongside dialysis to control antibody levels. Practical application includes treating severe autoimmune renal conditions. Challenges involve coagulation disturbances, volume overload, and need for vascular access capable of high flow rates.
Ultrafiltration Rate (UFR) #
Ultrafiltration Rate (UFR)
The volume of fluid removed per hour per kilogram of patient weight during hemod… #
Example: A UFR of 10 mL/kg/h is targeted to avoid intradialytic hypotension in a frail elderly patient. Practical monitoring helps prevent cardiovascular stress. Challenges include balancing adequate fluid removal with hemodynamic tolerance, especially in patients with limited residual urine output.
Ultra‑High‑Flux Dialyzers #
Ultra‑High‑Flux Dialyzers
Dialyzers engineered with pore sizes approaching 50‑kDa, allowing removal of lar… #
Example: A patient with refractory pruritus benefits from an ultra‑high‑flux dialyzer achieving greater clearance of cytokines. Practical use is expanding in research on dialysis‑related inflammation. Challenges involve strict monitoring for albumin loss, higher cost, and limited availability.
Vascular Access Surveillance #
Vascular Access Surveillance
A systematic program to monitor and maintain patency of hemodialysis access poin… #
Example: Quarterly access flow studies detect a 30 % decline, prompting pre‑emptive angioplasty. Practical impact includes reducing access-related hospitalizations. Challenges encompass resource allocation, patient compliance, and interpreting borderline flow values.
Water Treatment in Dialysis #
Water Treatment in Dialysis
The multi‑stage process (pretreatment, reverse osmosis, ultrafiltration) that en… #
Example: A clinic installs a double‑stage RO system to achieve <0.1 CFU/mL bacterial count. Practical importance lies in preventing endotoxin exposure and inflammatory reactions. Challenges include membrane fouling, regular maintenance schedules, and compliance with evolving standards.
Extended‑Hours Hemodialysis (EHD) #
Extended‑Hours Hemodialysis (EHD)
Dialysis sessions exceeding conventional 4‑hour durations, often 6‑8 hours, to i… #
Example: A thrice‑weekly 6‑hour regimen reduces phosphorus levels without phosphate binders. Practical benefits include better blood pressure control and reduced left‑ventricular hypertrophy. Challenges involve patient fatigue, scheduling constraints, and increased resource utilization.
Hybrid Dialysis Programs #
Hybrid Dialysis Programs
Structured treatment plans that integrate two or more dialysis techniques to exp… #
Example: A patient starts with conventional HD but transitions to supplemental peritoneal exchanges to preserve residual renal function. Practical application aims at extending time to full‑scale dialysis. Challenges include coordinating multiple access sites, ensuring consistent prescription, and managing differing complication profiles.
Incremental Hemodialysis #
Incremental Hemodialysis
A strategy that starts patients on fewer weekly sessions (e #
G., Twice weekly) when residual kidney function contributes significantly to solute clearance. Example: A newly diagnosed ESRD patient with urine output > 1 L/day begins twice‑weekly HD, adding sessions as function declines. Practical advantage is improved quality of life and slower loss of native kidney function. Challenges involve precise monitoring of residual clearance, patient education, and rapid escalation when needed.
Medium Cut‑Off (MCO) Membranes #
Medium Cut‑Off (MCO) Membranes
Dialyzer membranes designed with a narrow pore size distribution that allows rem… #
Example: An MCO dialyzer reduces inflammatory cytokines in a patient with chronic inflammation, improving fatigue scores. Practical impact includes bridging the gap between conventional high‑flux and sorbent therapies. Challenges encompass ensuring consistent manufacturing quality and monitoring for subtle albumin loss over long‑term use.
Peritoneal Dialysis Prescription Software #
Peritoneal Dialysis Prescription Software
Computer‑based tools that calculate optimal exchange volumes, dwell times, and g… #
Example: A clinician inputs a patient's PET results, and the software generates a CAPD regimen with 4 exchanges of 2 L each. Practical benefits include standardized prescribing and reduced calculation errors. Challenges include software licensing costs, need for regular updates, and ensuring data security.
Dialysate Sodium Modeling #
Dialysate Sodium Modeling
A technique that varies dialysate sodium concentration during a session to minim… #
Example: A program starts with 140 mmol/L sodium and gradually reduces to 135 mmol/L over 4 hours. Practical application supports better blood pressure control. Challenges involve accurate serum sodium monitoring, patient variability, and potential for sodium loading if not individualized.
Remote Monitoring of Dialysis Machines #
Remote Monitoring of Dialysis Machines
The use of internet‑connected dialysis units that transmit treatment parameters… #
G., Kt/V, UF volume) to clinicians for real‑time review. Example: A home hemodialysis patient’s session data is automatically uploaded, allowing the nurse to adjust prescription before the next treatment. Practical benefits include early detection of inadequate dialysis and equipment faults. Challenges encompass data privacy, reliable connectivity, and the need for staff trained in interpreting remote metrics.
Biocompatible Dialysis Membranes #
Biocompatible Dialysis Membranes
Membranes engineered to minimize activation of blood components, reducing cytoki… #
Example: A patient switched from cellulose acetate to a synthetic polysulfone membrane experiences fewer post‑dialysis fatigue episodes. Practical relevance includes improved tolerability and potentially better long‑term outcomes. Challenges involve higher cost and varying degrees of biocompatibility among manufacturers.
Anticoagulation Strategies in CRRT #
Anticoagulation Strategies in CRRT
Protocols to prevent clotting of extracorporeal circuits while minimizing bleedi… #
Example: Regional citrate anticoagulation maintains circuit patency for up to 72 hours without systemic anticoagulation, suited for patients with coagulopathy. Practical application reduces filter changes and blood loss. Challenges include monitoring calcium levels, citrate toxicity, and need for specialized infusion pumps.
Patient‑Reported Outcome Measures (PROMs) in Dialysis #
Patient‑Reported Outcome Measures (PROMs) in Dialysis
Standardized questionnaires that capture patients’ perspectives on health status… #
Example: The KDQOL‑36 is administered quarterly to assess the impact of switching from conventional HD to HDF. Practical use informs shared decision‑making and individualized care plans. Challenges involve ensuring cultural relevance, literacy considerations, and integrating results into routine clinical workflow.
Thermal Balance in Hemodialysis #
Thermal Balance in Hemodialysis
Adjustment of dialysate temperature (typically 35‑36 °C) to reduce intradialytic… #
Example: A patient prone to cramps tolerates cooler dialysate (34 °C) without compromising solute clearance. Practical implication includes personalized temperature settings. Challenges consist of potential for increased peripheral vasoconstriction, patient preference variability, and equipment limitations.
Dialysis‑Induced Amyloidosis Management #
Dialysis‑Induced Amyloidosis Management
Approaches to prevent or treat accumulation of amyloidogenic proteins in long‑te… #
Example: Transitioning a patient from low‑flux to high‑flux HDF reduces β2‑microglobulin levels and alleviates joint pain. Practical strategies also include use of MCO membranes and periodic monitoring. Challenges involve cost, patient adherence, and the irreversible nature of established amyloid deposits.
Glucose‑Sparing Peritoneal Dialysis Regimens #
Glucose‑Sparing Peritoneal Dialysis Regimens
Prescribing dialysate solutions with alternative osmotic agents to limit systemi… #
Example: Using 7.5 % Icodextrin for long‑dwelling exchanges reduces hyperglycemia in diabetic patients. Practical benefit includes better glycemic control and fewer lipid abnormalities. Challenges comprise higher cost, potential for allergic reactions, and limited availability in some regions.
Clinical Decision Support Systems (CDSS) for Dialysis #
Clinical Decision Support Systems (CDSS) for Dialysis
Software that integrates patient data to provide evidence‑based recommendations… #
Example: A CDSS alerts a clinician when a patient’s Kt/V falls below target, suggesting an increase in treatment time. Practical advantage includes standardization and reduced cognitive load. Challenges involve integration with legacy systems, false‑positive alerts, and ensuring clinician acceptance.
Phosphate Management in Advanced Dialysis #
Phosphate Management in Advanced Dialysis
Strategies to control serum phosphate through dialysate composition, frequency,… #
Example: Lowering dialysate phosphate to 0.8 Mmol/L combined with sevelamer reduces hyperphosphatemia without increasing calcium load. Practical relevance includes reducing vascular calcification risk. Challenges include balancing phosphate removal with risk of hypophosphatemia and patient adherence to dietary restrictions.
Biomarker‑Guided Dialysis Prescription #
Biomarker‑Guided Dialysis Prescription
Utilizing laboratory biomarkers to tailor dialysis intensity and modality #
Example: Elevated IL‑6 levels prompt transition to high‑volume HDF to enhance cytokine clearance. Practical application aims at personalized medicine. Challenges consist of assay availability, cost, and establishing clinically relevant thresholds.
Renal Replacement Therapy in Pregnancy #
Renal Replacement Therapy in Pregnancy
Adapting dialysis modalities to meet the increased metabolic demands and volume… #
Example: Increasing HD frequency to five sessions per week maintains urea < 15 mg/dL, supporting fetal growth. Practical aspects include careful anticoagulation and close monitoring of blood pressure. Challenges involve vascular access complications, medication safety, and coordinating multidisciplinary care.