Serum sodium shift in hyponatremic patients undergoing liver transplantation: a retrospective cohort study

Impact of octreotide on sodium level in cirrhotic inpatients with hyponatremia: a retrospective study

OBJECTIVE

Octreotide could increase serum sodium in cirrhotics with hyponatremia by counteracting splanchnic vasodilation. Current supporting data is limited to case reports and series. The aim of the study is to assess the effect of octreotide on serum sodium in cirrhotic inpatients with hyponatremia compared with controls.

METHODS

This is a retrospective study including adult inpatients with cirrhosis, admitted for ≥5 days with Na <133 at baseline. We excluded those receiving other vasoconstrictor infusions, hypertonic saline, tolvaptan or dialysis. Controls represented an equal number of inpatients with cirrhosis not receiving octreotide. Sodium changes on days 5, 7 and 10 were evaluated with multivariable adjustment.

RESULTS

Each group consisted of 156 patients. The octreotide subjects had more cirrhosis complications. Baseline sodium was lower in the octreotide group, and their change in sodium at day 5 was higher (6.6 ± 5.6 vs. 3.5 ± 5.3; P  < 0.001). Significant differences were also noted on days 7 and 10 (7.84 ± 6.76 vs. 4.33 ± 6.2 and 7.99 ± 6.72 vs. 5.2 ± 6.56, respectively). The impact of octreotide was lessened but remained significant ( P  = 0.019) in a mixed model adjusting for baseline sodium, creatinine, requirement of paracentesis, midodrine, albumin and fresh frozen plasma. More octreotide patients achieved hyponatremia resolution (55.1% vs. 42.3%; P  = 0.031), but significance was not preserved in multivariate logistic regression.

CONCLUSION

Octreotide administration is associated with an increase in serum sodium among inpatient cirrhotics with hyponatremia, even after accounting for confounders. Prospective randomized controlled trials are warranted.

Evidence-based hyponatremia management in liver disease

Hyponatremia is primarily a water balance disorder associated with high morbidity and mortality. The pathophysiological mechanisms behind hyponatremia are multifactorial, and diagnosing and treating this disorder remains challenging. In this review, the classification, pathogenesis, and step-by-step management approaches for hyponatremia in patients with liver disease are described based on recent evidence. We summarize the five sequential steps of the traditional diagnostic approach: 1) confirm true hypotonic hyponatremia, 2) assess the severity of hyponatremia symptoms, 3) measure urine osmolality, 4) classify hyponatremia based on the urine sodium concentration and extracellular fluid status, and 5) rule out any coexisting endocrine disorder and renal failure. Distinct treatment strategies for hyponatremia in liver disease should be applied according to the symptoms, duration, and etiology of disease. Symptomatic hyponatremia requires immediate correction with 3% saline. Asymptomatic chronic hyponatremia in liver disease is prevalent and treatment plans should be individualized based on diagnosis. Treatment options for correcting hyponatremia in advanced liver disease may include water restriction; hypokalemia correction; and administration of vasopressin antagonists, albumin, and 3% saline. Safety concerns for patients with liver disease include a higher risk of osmotic demyelination syndrome.

Intraoperative Renal Replacement Therapy in Orthotopic Liver Transplantation

Acute kidney injury in patients admitted to the hospital for liver transplantation is common, with up to 80% of pretransplant patients having some form of acute kidney injury. Many of these patients start on dialysis prior to their transplant and have it continued intraoperatively during their surgery. This review discusses the limited existing literature and expert opinion around the indications and outcomes around intraoperative dialysis (intraoperative renal replacement therapy) during liver transplantation. More specifically, we discuss which patients may benefit from intraoperative renal replacement therapy and the impact of hyponatremia and hyperammonemia on the dialysis prescription. Additionally, we discuss the complex interplay between anesthesia and intraoperative renal replacement therapy and how the need for clearance and ultrafiltration changes throughout the different phases of the transplant (preanhepatic, anhepatic, and postanhepatic). Lastly, this review will cover the limited data around patient outcomes following intraoperative renal replacement therapy during liver transplantation as well as the best evidence for when to stop dialysis.

Hyponatremia in Cirrhosis

Hyponatremia is the most common electrolyte disorder encountered in clinical practice, and it is a common complication of cirrhosis reflecting an increase in nonosmotic secretion of arginine vasopressin as a result of of the circulatory dysfunction that is characteristic of advanced liver disease. Hyponatremia in cirrhosis has been associated with poor clinical outcomes including increased risk of morbidity and mortality, poor quality of life, and heightened health care utilization. Despite this, the treatment of hyponatremia in cirrhosis remains challenging as conventional therapies such as fluid restriction are frequently ineffective. In this review, we discuss the epidemiology, clinical outcomes, pathogenesis, etiology, evaluation, and management of hyponatremia in cirrhosis.

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.

Clinical Implications, Evaluation, and Management of Hyponatremia in Cirrhosis

Hyponatremia is the most common electrolyte abnormality in patients with decompensated cirrhosis on Liver Transplantation (LT) waiting list. Most of these patients have dilutional or hypervolemic hyponatremia secondary to splanchnic vasodilatation. Excessive secretion of the antidiuretic hormone also plays an important role. Hypervolemic hyponatremia is commonly associated with refractory ascites, spontaneous bacterial peritonitis, and hepatic encephalopathy. Although uncommon, the use of diuretics and laxatives can cause hypovolemic hyponatremia that is characterized by the striking absence of ascites or pedal edema. Clinical features are often nonspecific and depend on the acuity of onset rather than the absolute value of serum sodium. Symptoms may be subtle, including nausea, lethargy, weakness, or anorexia. However, rarely patients may present with confusion, seizures, psychosis, or coma. Treatment includes discontinuation of diuretics, beta-blockers, and albumin infusion. Hypertonic saline (3%) infusion may be used in patients with very low serum sodium (<110 mmol/L) or when patients present with seizures or coma. Short-term use of Vasopressin (V₂) receptor antagonists may also be used to normalize sodium levels prior to LT. However, all these measures may be futile, and LT remains the definite treatment in these patients to improve survival. In this review, we describe the classification, pathogenesis of hyponatremia, and its clinical implications in patients with cirrhosis. Approach to these patients along with management will also be discussed briefly.

Perioperative Evolution of Sodium Levels in Cirrhotic Patients Undergoing Liver Transplantation: An Observational Cohort and Literature Review

Background & Aims

Hyponatremia is an important predictor of early death among cirrhotic patients in the orthotopic liver transplantation (OLT) waiting list. Evidence exists that prioritizing OLT waiting list according to the MELD score combined with plasma sodium concentration might prevent pre transplantation death. However, the evolution of plasma sodium concentrations during the perioperative period of OLT is not well known. We aimed to describe the evolution of perioperative sodium concentration during OLT and its relation to perioperative neurohormonal responses.

Methods

Twenty-seven consecutive cirrhotic patients who underwent OLT were prospectively included in the study over a period of 27 months. We studied the evolution of plasma sodium levels, the hemodynamics, the neurohormonal response and other biological markers during the perioperative period of OLT.

Results

Among study's population, four patients had hyponatremia before OLT, all with Child cirrhosis. In patients with hyponatremia, plasmatic sodium reached normal levels during surgery, and sodium levels remained within normal ranges 1 day, 7 days, as well as 6 months after surgery for all patients. Creatinine clearance was decreased significantly during the perioperative period, while creatinine and cystatin C levels increased significantly. Neutrophil gelatinase-associated lipocalin (NGAL) and vasopressin levels did not change significantly in this period. Plasma renin activity, concentrations of norepinephrine and brain natriuretic peptide varied significantly during the perioperative period.

Conclusion

In our study, plasmatic sodium concentrations among hyponatremic cirrhotic patients undergoing OLT seem to reach normal levels after OLT and remain stable six months after surgery providing more evidence for the importance of sodium levels in prioritization of liver transplant candidates. Further investigation of rapid correction and stabilization of sodium levels after OLT, as observed in our study, would be of interest in order to fully understand the mechanisms involved in cirrhosis-related hyponatremia, its prognostic value and clinical implications.

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.

Criteria for Hyponatremic Overcorrection: Systematic Review and Cohort Study of Emergently Ill Patients

BACKGROUND

Hyponatremia is the most common electrolyte disturbance amongst hospitalized patients. An overly rapid rate of correction of chronic hyponatremia is believed to increase the risk of poor clinical outcomes including osmotic demyelination syndrome (ODS). There is disagreement in the literature regarding the definition of hyponatremic overcorrection.

METHODS

We performed a systematic review of all English language studies to identify those that calculated sodium correction rate and classified patients' overcorrection status. We then identified all patients who presented to our hospital's emergency department between 2003 and 2015 with a corrected serum sodium ≤ 116 mmol/L. All methods from the systematic review for sodium correction rate calculation and overcorrection status were applied to this cohort.

RESULTS

We identified 24 studies citing 9 distinct sodium correction rate methods and 14 criteria for overcorrection. Six hundred twenty-four patients presenting with severe hyponatremia (median initial value 113 mMol) were identified. Depending on the method used, the median sodium correction rates in our cohort ranged from 0.271 to 1.13 mmol/L per hour. The proportion of patients classified with overcorrection with the different criteria varied almost 11-fold, ranging from 8.5 to 89.9%.

CONCLUSION

Published methods disagree regarding the calculation of sodium correction rates and the definition of hyponatremic overcorrection. This leads to wide variations in sodium correction rates and the prevalence of overcorrection in patient cohorts. Definitions based on ODS risk are needed.

Derivation and Validation of a Novel Risk Score to Predict Overcorrection of Severe Hyponatremia: The Severe Hyponatremia Overcorrection Risk (SHOR) Score

BACKGROUND AND OBJECTIVES

Osmotic demyelination syndrome is the most concerning complication of severe hyponatremia, occurring with an overly rapid rate of serum sodium correction. There are limited clinical tools to aid in identifying individuals at high risk of overcorrection with severe hyponatremia.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We identified all patients who presented to a tertiary-care hospital emergency department in Ottawa, Canada (catchment area 1.2 million) between January 1, 2003 and December 31, 2015, with serum sodium (corrected for glucose levels) <116 mmol/L. Overcorrection was determined using 14 published criteria. Latent class analysis measured the independent association of baseline factors with a consensus overcorrection status on the basis of the 14 criteria, and was summarized as a risk score, which was validated in two cohorts.

RESULTS

A total of 623 patients presented with severe hyponatremia (mean initial value 112 mmol/L; SD 3.2). The prevalence of no, unlikely, possible, and definite overcorrection was 72%, 4%, 10%, and 14%, respectively. Overcorrection was independently associated with decreased level of consciousness (2 points), vomiting (2 points), severe hypokalemia (1 point), hypotonic urine (4 points), volume overload (-5 points), chest tumor (-5 points), patient age (-1 point per decade, over 50 years), and initial sodium level (<110 mmol/L: 4 points; 110-111 mmol/L: 2 points; 112-113 mmol/L: 1 point). These points were summed to create the Severe Hyponatremic Overcorrection Risk (SHOR) score, which was significantly associated with overcorrection status (Spearman correlation 0.45; 95% confidence interval, 0.36 to 0.49) and was discriminating (average dichotomized c-statistic 0.77; 95% confidence interval, 0.73 to 0.81). The internal (n=119) and external (n=95) validation cohorts had significantly greater use of desmopressin, which was significantly associated with the SHOR score. The SHOR score was significantly associated with overcorrection status in the internal (P<0.001) but not external (P=0.39) validation cohort.

CONCLUSIONS

In patients presenting with severe hyponatremia, overcorrection was common and predictable using baseline information. Further external validation of the SHOR is required before generalized use.

Hyponatremia in Cirrhosis: Implications for Liver Transplantation

Hyponatremia in cirrhosis is defined as a serum sodium level ≤130 mEq/L and occurs in approximately 22% of patients with cirrhosis. The appearance of hyponatremia in patients with cirrhosis portends a poor prognosis before liver transplantation (LT), independent of the Model for End-Stage Liver Disease (MELD) score. With the development of the MELD-sodium score, the management of hyponatremia has become more relevant than ever before. Overcorrection of hyponatremia before LT or perioperatively can lead to the devastating neurologic condition known as osmotic demyelination syndrome, which is often irreversible and fatal. Therefore, the most important tenet of hyponatremia is to avoid correcting the serum sodium by ≥8 mEq/L in a 24-hour period. Treatment of hyponatremia is highly challenging. The vast majority of patients with cirrhosis have chronic hypervolemic hyponatremia. Fluid restriction increases serum sodium levels, but tolerance and compliance are significant barriers. Diuretic withdrawal is helpful but contributes to worsening fluid overload. There are limited data to support use of intravenous concentrated albumin solutions. The use of the arginine vasopressin antagonists ("vaptans") is contentious; however, they may have a limited role. Risk factors for intraoperative overcorrection of serum sodium include increased utilization of packed red blood cell and fresh frozen plasma transfusions, which are often unavoidable. Intraoperative management is evolving, and more data are needed in regard to the use of sodium-reduced continuous venovenous hemofiltration and the use of trishydroxymethylaminomethane (Tris) to avoid excess sodium rebound. A thorough discussion of the current treatment options before and during LT is given in this review.

Prevention of the Osmotic Demyelination Syndrome After Liver Transplantation: A Multidisciplinary Perspective

The osmotic demyelination syndrome (ODS) is a serious neurologic condition that occurs in the setting of rapid correction of hyponatremia. It presents with protean manifestations, from encephalopathy to the "locked-in" syndrome. ODS can complicate liver transplantation (LT), and its incidence may increase with the inclusion of serum sodium as a factor in the Mayo End-Stage Liver Disease score. A comprehensive understanding of risk factors for the development of ODS in the setting of LT, along with recommendations to mitigate the risk of ODS, are necessary. The literature to date on ODS in the setting of LT was reviewed. Major risk factors for the development of ODS include severe pretransplant hyponatremia (serum sodium [SNa] < 125 mEq/L), the magnitude of change in SNa pre- versus posttransplant, higher positive intraoperative fluid balance, and the presence of postoperative hemorrhagic complications. Strategies to reduce the risk of ODS include correcting hyponatremia pretransplant via fluid restriction and/or ensuring an appropriate rate of increase from the preoperative SNa via close attention to fluid and electrolyte management both during and after surgery. Multidisciplinary management involving transplant hepatology, nephrology, neurology, surgery, and anesthesiology/critical care is key to performing LT safely in patients with hyponatremia.