A Multidisciplinary Approach for the Management of Severe Hyponatremia in Patients Requiring Continuous Renal Replacement Therapy

Treatment of severe hyponatremia with continuous renal replacement therapy: A case and review of corrective strategies

Treatment of severely hyponatremic patients with continuous renal replacement therapy (CRRT) presents a unique challenge given the lack of commercial options for hypotonic replacement solutions or dialysate. We report the case of a 55-year-old male who presented with profound, symptomatic hyponatremia in the setting of acute kidney injury (AKI). The patient was found to have a serum sodium concentration of 97 mEq/L because of free water retention that occurred during severe AKI from viral gastroenteritis and rhabdomyolysis. Continuous veno-venous hemofiltration (CVVH) was required for AKI complicated by hyperkalemia, metabolic acidosis, and uremia. To prevent overcorrection of serum sodium, replacement fluids customized to natremic status had to be prepared. Conventional replacement fluid was modified on a daily basis to create hypotonic solutions with successively higher sodium concentrations. Over the course of a week, serum sodium successfully improved in a controlled and safe fashion. This case incorporates and reviews the variety of methods that have been used to safely manage severe hyponatremia with CRRT.

Acute Kidney Injury: Gaps and Opportunities for Knowledge and Growth

Acute kidney injury (AKI) occurs frequently in hospitalized patients, regardless of age or prior medical history. Increasing awareness of the epidemiologic problem of AKI has directly led to increased study of global recognition, diagnostic tools, both reactive and proactive management, and analysis of long-term sequelae. Many gaps remain, however, and in this article we highlight opportunities to add significantly to the increasing bodies of evidence surrounding AKI. Practical considerations related to initiation, prescription, anticoagulation, and monitoring are discussed. In addition, the importance of AKI follow-up evaluation, particularly for those surviving the receipt of renal replacement therapy, is highlighted as a push for global equity in the realm of critical care nephrology is broached. Addressing these gaps presents an opportunity to impact patient care directly and improve patient outcomes.

Initiating Continuous Renal Replacement Therapy in Patients With Transurethral Resection of Prostate Syndrome: A Case Report

With advances and developments in hysteroscopy, cystoscopy, transurethral resection of bladder tumor, and arthroscopy, transurethral resection of prostate (TURP) syndrome has been increasingly reported. TURP syndrome is often accompanied by severe hyponatremia, fluid overload, and a plasma hypotonic state, resulting in heart failure and pulmonary and cerebral edema. Conventional treatment methods, such as intravenous infusion of hyperosmotic saline, can rapidly reverse the downward trend of serum sodium levels in efforts to prevent and treat cerebral edema. However, this may not be suitable for patients with cardiac and renal insufficiency and may induce central pontine myelinolysis due to the possibility of worsening volume load and difficulty in controlling the correction rate of serum sodium. The patient described in this report presented with severe hyponatremia (sodium<100 mmol/L) combined with intraoperative pulmonary edema; his cardiac function and oxygenation status deteriorated after an intravenous infusion of 3% hypertonic saline. He underwent continuous renal replacement therapy (CRRT) to prevent the progression of multiple-organ edema and cardiac insufficiency. CRRT has demonstrated efficacy in the treatment of chronic hyponatremia in patients with renal failure, and can slowly and continuously correct water-electrolyte imbalance, acid-base imbalance, and volume overload. TURP syndrome with severe hyponatremia and pulmonary edema was diagnosed; accordingly, the patient was treated with 3% hypertonic saline, furosemide, and CRRT, without the development of overt neurological sequelae.

Management for Electrolytes Disturbances during Continuous Renal Replacement Therapy

Despite the lack of proven superiority in mortality compared to intermittent hemodialysis, continuous renal replacement therapy (CRRT) is the preferred renal replacement therapy modality for critically ill patients with acute kidney injury (AKI) due to better hemodynamic stability and steady correction of electrolytes disturbances and volume overload. Multiple and complex electrolyte disorders in patients with AKI can be managed effectively with CRRT because controlled and predictable correction is feasible. Thus, CRRT has an advantage with safety over conventional hemodialysis, especially in patients with both renal dysfunction and electrolyte disorder that require a sophisticated treatment with avoidance of rapid correction. On the contrary, CRRT can potentially lead to paradoxical disturbance of electrolytes such as hypokalemia or hypophosphatemia, especially in patients under high dose or prolonged duration of CRRT treatment. These electrolytes related complications can be prevented with close monitoring followed by the appropriate use of CRRT fluids. Although there is a lack of solid evidence and standardized guideline for CRRT prescriptions, optimal management of various electrolyte disturbances can be achieved with individualized and tailored dialysate and replacement fluid prescriptions. Several commercially available CRRT solutions with varying compositions provide flexibility to manage electrolyte disorders and maintain the stability of electrolyte. In this review, we discuss various prescription methods to manage common electrolyte imbalances as well as preventative strategies to maintain electrolyte homeostasis during CRRT providing detailed protocols used in our center. This review may contribute to future research that can lead to the development of clinical practice guidelines.

Delivering optimal renal replacement therapy to critically ill patients with acute kidney injury

Critical illness is often complicated by acute kidney injury (AKI). In patients with severe AKI, renal replacement therapy (RRT) is deployed to address metabolic dysfunction and volume excess until kidney function recovers. This review is intended to provide a comprehensive update on key aspects of RRT prescription and delivery to critically ill patients. Recently completed trials have enhanced the evidence base regarding several RRT practices, most notably the timing of RRT initiation and anticoagulation for continuous therapies. Better evidence is still needed to clarify several aspects of care including optimal targets for ultrafiltration and effective strategies for RRT weaning and discontinuation.

Complications Associated with Continuous RRT

Continuous renal replacement therapy (CRRT) is a form of renal replacement therapy that is used in modern intensive care units (ICUs) to help manage acute kidney injury (AKI), end stage kidney disease (ESKD), poisonings, and some electrolyte disorders. CRRT has transformed the care of patients in the ICU over the past several decades. In this setting, it is important to recognize CRRT-associated complications but also up-to-date management of these complications. Some of these complications are minor, but others may be more significant and even life-threatening. Some CRRT complications may be related to dialysis factors and others to specific patient factors. Our overarching goal in this article is to review and discuss the most significant CRRT-related complications at the different stage of management of CRRT. With the advent of newer solutions, there have been newer complications as well.

Can Artificial Intelligence Assist in Delivering Continuous Renal Replacement Therapy?

Continuous renal replacement therapy (CRRT) is widely utilized to support critically ill patients with acute kidney injury. Artificial intelligence (AI) has the potential to enhance CRRT delivery, but evidence is limited. We reviewed existing literature on the utilization of AI in CRRT with the objective of identifying current gaps in evidence and research considerations. We conducted a scoping review focusing on the development or use of AI-based tools in patients receiving CRRT. Ten papers were identified; 6 of 10 (60%) published in 2021, and 6 of 10 (60%) focused on machine learning models to augment CRRT delivery. All innovations were in the design/early validation phase of development. Primary research interests focused on early indicators of CRRT need, prognostication of mortality and kidney recovery, and identification of risk factors for mortality. Secondary research priorities included dynamic CRRT monitoring, predicting CRRT-related complications, and automated data pooling for point-of-care analysis. Literature gaps included prospective validation and implementation, biases ascertainment, and evaluation of AI-generated health care disparities. Research on AI applications to enhance CRRT delivery has grown exponentially in the last years, but the field remains premature. There is a need to evaluate how these applications could enhance bedside decision-making capacity and assist structure and processes of CRRT delivery.

Electrolyte, acid-base, and medication management with renal replacement therapy

Fluid and electrolyte homeostasis exhibited by the kidneys is a complex process that is challenging to regulate with artificial renal replacement therapy (RRT). RRT has been used as a treatment modality for electrolyte and acid-base disturbances in patients with acute kidney injury and chronic kidney disease. This review highlights the management of electrolyte shifts, acid-base disturbances, and medication considerations in RRT, with a focus on intermittent hemodialysis and continuous RTT in the inpatient setting.

Hyponatremia and Liver Transplantation: A Narrative Review

Hyponatremia is a common electrolyte disorder in patients with end-stage liver disease (ESLD) and is associated with increased mortality on the liver transplantation (LT) waiting list. The impact of hyponatremia on outcomes after LT is unclear. Ninety-day and one-year mortality may be increased, but the data are conflicting. Hyponatremic patients have an increased rate of complications and longer hospital stays after transplant. Although rare, osmotic demyelination syndrome (ODS) is a feared complication after LT in the hyponatremic patient. The condition may occur when the serum sodium (sNa) concentration increases excessively during or after LT. This increase in sNa concentration correlates with the degree of preoperative hyponatremia, the amount of intraoperative blood loss, and the volume of intravenous fluid administration. The risk of developing ODS after LT can be mitigated by avoiding large perioperative increases in sNa concentration . This can be achieved through measures such as carefully increasing the sNa pretransplant, and by limiting the intravenous intra- and postoperative amounts of sodium infused. SNa concentrations should be monitored regularly throughout the entire perioperative period.

Correction of severe hyponatremia by continuous veno-venous hemodialysis with regional citrate anticoagulation: A case series

INTRODUCTION

Hyponatremia is a common electrolyte disturbance in critically ill patients. Management of Intensive Care Unit (ICU) patients with concurrent hyponatremia and renal failure requiring dialysis is challenging especially with regional citrate anticoagulation which may cause excessive rise of serum [Na⁺ ]. We described the first and successful modified continuous veno-venous hemodialysis (CVVHD) regimen using regional citrate anticoagulation.

METHOD

A mathematical model was developed to predict serum [Na⁺ ] change during CVVHD. Our in-house CVVHD regimen using regional citrate anticoagulation was modified to slow down the rise of serum [Na⁺ ] by both modifying the dialysate solution and modifying the circuit.

RESULT

Five out of six patients had gradual serum [Na⁺ ] correction not exceeding the daily limit. None of them developed osmotic demyelination syndrome.

CONCLUSION

We concluded that regional citrate anticoagulation, with proper modification, is safe and effective for patients with severe hyponatremia requiring hemodialysis.

Correcting hyponatremia by fluid sodium modulation in continuous renal replacement therapy with regional citrate anticoagulation

A 40-year-old man presented with severe hyponatremia with a serum sodium of 102 mmol/L and concomitant acute kidney injury complicated by severe acidosis. He was started on continuous renal replacement therapy (CRRT) with regional citrate anticoagulation. We present the equations and strategy used to calculate and adjust the sodium concentration of the dialysate and replacement fluids to increase serum sodium levels by ≤8 mmol/L/day. The equations were based on fundamental chemistry principles and applicable to common CRRT solutions with 140 mmol/L of sodium. This simple strategy for CRRT fluid sodium titration required only one adjustment per day, and the serum sodium levels increased safely within the daily targets set. Although the citrated-replacement fluid was diluted for sodium adjustment, the citrate anticoagulation protocol was still able to achieve the targeted circuit ionized-calcium levels and provided adequate anticoagulation without issues related to frequent clotting and other electrolyte abnormalities.

Dysnatremias in Chronic Kidney Disease: Pathophysiology, Manifestations, and Treatment

The decreased ability of the kidney to regulate water and monovalent cation excretion predisposes patients with chronic kidney disease (CKD) to dysnatremias. In this report, we describe the clinical associations and methods of management of dysnatremias in this patient population by reviewing publications on hyponatremia and hypernatremia in patients with CKD not on dialysis, and those on maintenance hemodialysis or peritoneal dialysis. The prevalence of both hyponatremia and hypernatremia has been reported to be higher in patients with CKD than in the general population. Certain features of the studies analyzed, such as variation in the cut-off values of serum sodium concentration ([Na]) that define hyponatremia or hypernatremia, create comparison difficulties. Dysnatremias in patients with CKD are associated with adverse clinical conditions and mortality. Currently, investigation and treatment of dysnatremias in patients with CKD should follow clinical judgment and the guidelines for the general population. Whether azotemia allows different rates of correction of [Na] in patients with hyponatremic CKD and the methodology and outcomes of treatment of dysnatremias by renal replacement methods require further investigation. In conclusion, dysnatremias occur frequently and are associated with various comorbidities and mortality in patients with CKD. Knowledge gaps in their treatment and prevention call for further studies.

Association of Phosphate Containing Solutions with Incident Hypophosphatemia in Critically Ill Patients Requiring Continuous Renal Replacement Therapy

BACKGROUND

Hypophosphatemia in critically ill patients is a common electrolyte disturbance associated with a myriad of adverse effects. Critically ill patients requiring continuous renal replacement therapy (CRRT) are at high risk of hypophosphatemia and often require phosphate supplementation during therapy. The aim of this study was to evaluate the association of phosphate versus non-phosphate containing CRRT solutions with incident hypophosphatemia in critically ill patients requiring CRRT.

MATERIALS AND METHODS

This is a single-center, retrospective, cohort study at a tertiary academic medical center of 1,396 adult patients requiring CRRT during their intensive care unit stay comprising 7,529 (phosphate containing) and 4,821 (non-phosphate containing) cumulative days of CRRT. Multivariable logistic regression was used to model the primary outcome of hypophosphatemia during CRRT according to exposure to phosphate versus non-phosphate containing CRRT solutions.

RESULTS

Incident hypophosphatemia during CRRT, serum phosphate <2.5 mg/dL or 0.81 mmol/L, was significantly higher in the non-phosphate versus phosphate containing solution group: 304/489 (62%) versus 175/853 (21%) (p < 0.001). Cumulative phosphate supplementation was also significantly higher in the non-phosphate versus phosphate containing solution group: 79 (IQR: 0-320) versus 0 (0-16) mmol (p < 0.001). Non-phosphate solutions were associated with an 8-fold increase in the incidence of hypophosphatemia (adjusted OR 8.05; 95% CI 5.77, 11.26; p < 0.001).

DISCUSSION/CONCLUSIONS

The use of phosphate containing CRRT solutions was independently associated with reduced risk of incident hypophosphatemia and decreased phosphate supplementation during CRRT. Interventional studies to confirm these findings are needed.

How To Prescribe And Troubleshoot Continuous Renal Replacement Therapy: A Case-Based Review

Continuous RRT (CRRT) is the preferred dialysis modality for solute management, acid-base stability, and volume control in patients who are critically ill with AKI in the intensive care unit (ICU). CRRT offers multiple advantages over conventional hemodialysis in the critically ill population, such as greater hemodynamic stability, better fluid management, greater solute control, lower bleeding risk, and a more continuous (physiologic) approach of kidney support. Despite its frequent use, several aspects of CRRT delivery are still not fully standardized, or do not have solid evidence-based foundations. In this study, we provide a case-based review and recommendations of common scenarios and interventions encountered during the provision of CRRT to patients who are critically ill. Specific focus is on initial prescription, CRRT dosing, and adjustments related to severe hyponatremia management, concomitant extracorporeal membrane oxygenation support, dialysis catheter placement, use of regional citrate anticoagulation, and antibiotic dosing. This case-driven simulation is made as the clinical status of the patient evolves, and is on the basis of step-wise decisions made during the care of this patient, according to the specific patient's needs and the logistics available at the corresponding institution.

Development, implementation and outcomes of a quality assurance system for the provision of continuous renal replacement therapy in the intensive care unit

Critically ill patients with requirement of continuous renal replacement therapy (CRRT) represent a growing intensive care unit (ICU) population. Optimal CRRT delivery demands continuous communication between stakeholders, iterative adjustment of therapy, and quality assurance systems. This Quality Improvement (QI) study reports the development, implementation and outcomes of a quality assurance system to support the provision of CRRT in the ICU. This study was carried out at the University of Kentucky Medical Center between September 2016 and June 2019. We implemented a quality assurance system using a step-wise approach based on the (a) assembly of a multidisciplinary team, (b) standardization of the CRRT protocol, (c) creation of electronic CRRT flowsheets, (d) selection, monitoring and reporting of quality metrics of CRRT deliverables, and (e) enhancement of education. We examined 34-month data comprising 1185 adult patients on CRRT (~ 7420 patient-days of CRRT) and tracked selected QI outcomes/metrics of CRRT delivery. As a result of the QI interventions, we increased the number of multidisciplinary experts in the CRRT team and ensured a continuum of education to health care professionals. We maximized to 100% the use of continuous veno-venous hemodiafiltration and doubled the percentage of patients using regional citrate anticoagulation. The delivered CRRT effluent dose (~ 30 ml/kg/h) and the delivered/prescribed effluent dose ratio (~ 0.89) remained stable within the study period. The average filter life increased from 26 to 31 h (p = 0.020), reducing the mean utilization of filters per patient from 3.56 to 2.67 (p = 0.054) despite similar CRRT duration and mortality rates. The number of CRRT access alarms per treatment day was reduced by 43%. The improvement in filter utilization translated into ~ 20,000 USD gross savings in filter cost per 100-patient receiving CRRT. We satisfactorily developed and implemented a quality assurance system for the provision of CRRT in the ICU that enabled sustainable tracking of CRRT deliverables and reduced filter resource utilization at our institution.

Hyponatremia in Cirrhosis: An Update

Hyponatremia is frequently seen in patients with ascites secondary to advanced cirrhosis and portal hypertension. Although not apparent in the early stages of cirrhosis, the progression of cirrhosis and portal hypertension leads to splanchnic vasodilation, and this leads to the activation of compensatory mechanisms such as renin-angiotensin-aldosterone system (RAAS), sympathetic nervous system, and antidiuretic hormone (ADH) to ameliorate low circulatory volume. The net effect is the avid retention of sodium and water to compensate for the low effective circulatory volume, resulting in the development of ascites. These compensatory mechanisms lead to impairment of the kidneys to eliminate solute-free water in decompensated cirrhosis. Nonosmotic secretion of antidiuretic hormone (ADH), also known as arginine vasopressin, further worsens excess water retention and thereby hyponatremia. The management of hyponatremia in this setting is a challenge as conventional therapies for hyponatremia including fluid restriction and correction of hypokalemia are frequently inefficacious. In this review, we discuss the pathophysiology, complications, and various treatment modalities, including albumin infusion, selective vasopressin receptor antagonists, or hypertonic saline for patients with severe hyponatremia and those awaiting liver transplantation.

Severe Hyponatremia and Continuous Renal Replacement Therapy: Safety and Effectiveness of Low-Sodium Dialysate

RATIONALE & OBJECTIVE

In patients with severe hyponatremia in the setting of acute kidney injury or end-stage kidney disease, continuous renal replacement therapy (CRRT) using standard-sodium (140 mEq/L) fluids may lead to excessively rapid correction of plasma sodium concentration. Use of dialysate and replacement fluids with reduced sodium concentrations can provide a controlled rate of correction of plasma sodium concentration.

STUDY DESIGN

We performed a single-center retrospective analysis of the safety and effectiveness of this approach in patients with plasma sodium concentrations ≤ 126 mEq/L who underwent CRRT for 24 or more hours using low-sodium (119 or 126 mEq/L) dialysate and replacement fluids. Change in plasma sodium level was assessed at 24 and 48 hours after initiation of low-sodium CRRT and at the end of treatment.

SETTING & PARTICIPANTS

Between January 2016 and June 2018, a total of 23 hyponatremic patients underwent continuous venovenous hemodiafiltration using low-sodium dialysate and replacement fluids; 4 patients were excluded from analysis because of CRRT duration less than <24 hours.

RESULTS

The 19 patients included in the study had a mean age of 56 years, 11 (58%) were men, and 15 (79%) were white. The initial mean plasma sodium level was 121 mEq/L and the initial CRRT effluent dose was 27 mL/kg/h. Only 2 (11%) patients had an increase in plasma sodium concentration > 6 mEq/L at 24 hours. Mean changes in plasma sodium levels at 24 and 48 hours and at the time of CRRT discontinuation were 3, 3, and 6 mEq/L, respectively. None of the patients developed osmotic demyelination syndrome.

LIMITATIONS

Key limitations were small sample size and lack of a control group.

CONCLUSIONS

Use of low-sodium dialysate and replacement fluids is a safe strategy for the prevention of overly rapid correction of plasma sodium levels in hyponatremic patients undergoing CRRT.