A balancing act: drifting away from the reflexive use of "ab"normal saline

Maintenance intravenous fluids are the most frequently ordered medications for hospitalized children. Since the American Association of Pediatrics published national guidelines, there has been an increased reflexive use of isotonic solutions, especially 0.9% saline, as a prophylaxis against hyponatremia. In this educational review, we discuss the potential deleterious effects of using 0.9% saline, including the development of hyperchloremia, metabolic acidosis, acute kidney injury, hyperkalemia, and a proinflammatory state. Balanced solutions with anion buffers cause relatively minimal harm when used in most children. While the literature supporting one fluid choice over the other is variable, we highlight the benefits of balanced solutions over saline and the importance of prescribing fluid therapy that is individualized for each patient.

Choosing fluids to reduce the risks of acute electrolyte disturbances in children after a kidney transplant

Intravenous (i.v.) fluid therapy is critically important in pediatric kidney transplantation. Because of the high volumes given perioperatively, transplant recipients can develop significant electrolyte abnormalities depending on the types of fluids used. Current practices in pediatric transplantation aim to balance risks of hyponatremia from traditionally used hypotonic fluids, such as 0.45% sodium chloride, against hyperchloremia and acidosis associated with isotonic 0.9% sodium chloride. Using the balanced solution Plasma-Lyte 148 as an alternative might mitigate these risks.

Efficacy and safety of isotonic versus hypotonic intravenous maintenance fluids in hospitalized children: an updated systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Iatrogenic hyponatremia is a common complication following intravenous maintenance fluid therapy (IV-MFT) in hospitalized children. Despite the American Academy of Pediatrics' 2018 recommendations, IV-MFT prescribing practices still vary considerably.

OBJECTIVES

This meta-analysis aimed to compare the safety and efficacy of isotonic versus hypotonic IV-MFT in hospitalized children.

DATA SOURCES

We searched PubMed, Scopus, Web of Science, and Cochrane Central from inception to October 1, 2022.

STUDY ELIGIBILITY CRITERIA

We included randomized controlled trials (RCTs) comparing isotonic versus hypotonic IV-MFT in hospitalized children, either with medical or surgical conditions. Our primary outcome was hyponatremia following IV-MFT. Secondary outcomes included hypernatremia, serum sodium, serum potassium, serum osmolarity, blood pH, blood sugar, serum creatinine, serum chloride, urinary sodium, length of hospital stay, and adverse outcomes.

STUDY APPRAISAL AND SYNTHESIS METHODS

Random-effects models were used to pool the extracted data. We performed our analysis based on the duration of fluid administration (i.e., ≤ 24 and > 24 h). The Grades of Recommendations Assessment Development and Evaluation (GRADE) scale was used to evaluate the strength and level of evidence for recommendations.

RESULTS

A total of 33 RCTs, comprising 5049 patients were included. Isotonic IV-MFT significantly reduced the risk of mild hyponatremia at both ≤ 24 h (RR = 0.38, 95% CI [0.30, 0.48], P < 0.00001; high quality of evidence) and > 24 h (RR = 0.47, 95% CI [0.37, 0.62], P < 0.00001; high quality of evidence). This protective effect of isotonic fluid was maintained in most examined subgroups. Isotonic IV-MFT significantly increased the risk of hypernatremia in neonates (RR = 3.74, 95% CI [1.42, 9.85], P = 0.008). In addition, it significantly increased serum creatinine at ≤ 24 h (MD = 0.89, 95% CI [0.84, 0.94], P < 0.00001) and decreased blood pH (MD = -0.05, 95% CI [-0.08 to -0.02], P = 0.0006). Mean serum sodium, serum osmolarity, and serum chloride were lower in the hypotonic group at ≤ 24 h. The two fluids were comparable in terms of serum potassium, length of hospital stay, blood sugar, and the risk of adverse outcomes.

LIMITATIONS

The main limitation of our study was the heterogeneity of the included studies.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Isotonic IV-MFT was superior to the hypotonic one in reducing the risk of iatrogenic hyponatremia in hospitalized children. However, it increases the risk of hypernatremia in neonates and may lead to renal dysfunction. Given that the risk of hypernatremia is not important even in the neonates, we propose to use balanced isotonic IV-MFT in hospitalized children as it is better tolerated by the kidneys than 0.9% saline.

SYSTEMATIC REVIEW REGISTRATION NUMBER

CRD42022372359. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information.

Pediatric perioperative fluid management

The purpose of perioperative fluid management in children is to maintain adequate volume status, electrolyte level, and endocrine system homeostasis during the perioperative period. Although hypotonic solutions containing glucose have traditionally been used as pediatric maintenance fluids, recent studies have shown that isotonic balanced crystalloid solutions lower the risk of hyponatremia and metabolic acidosis perioperatively. Isotonic balanced solutions have been found to exhibit safer and more physiologically appropriate characteristics for perioperative fluid maintenance and replacement. Additionally, adding 1-2.5% glucose to the maintenance fluid can help prevent children from developing hypoglycemia as well as lipid mobilization, ketosis, and hyperglycemia. The fasting time should be as short as possible without compromising safety; recent guidelines have recommended that the duration of clear fluid fasting be reduced to 1 h. The ongoing loss of fluid and blood as well as the free water retention induced by antidiuretic hormone secretion are unique characteristics of postoperative fluid management that must be considered. Reducing the infusion rate of the isotonic balanced solution may be necessary to avoid dilutional hyponatremia during the postoperative period. In summary, perioperative fluid management in pediatric patients requires careful attention because of the limited reserve capacity in this population. Isotonic balanced solutions appear to be the safest and most beneficial choice for most pediatric patients, considering their physiology and safety concerns.

Effect of an Albumin Infusion Treatment Protocol on Delayed Cerebral Ischemia and Relevant Outcomes in Patients with Subarachnoid Hemorrhage

BACKGROUND

An institutional management protocol for patients with subarachnoid hemorrhage (SAH) based on initial cardiac assessment, permissiveness of negative fluid balances, and use of a continuous albumin infusion as the main fluid therapy for the first 5 days of the intensive care unit (ICU) stay was implemented at our hospital in 2014. It aimed at achieving and maintaining euvolemia and hemodynamic stability to prevent ischemic events and complications in the ICU by reducing periods of hypovolemia or hemodynamic instability. This study aimed at assessing the effect of the implemented management protocol on the incidence of delayed cerebral ischemia (DCI), mortality, and other relevant outcomes in patients with SAH during ICU stay.

METHODS

We conducted a quasi-experimental study with historical controls based on electronic medical records of adults with SAH admitted to the ICU at a tertiary care university hospital in Cali, Colombia. The patients treated between 2011 and 2014 were the control group, and those treated between 2014 and 2018 were the intervention group. We collected baseline clinical characteristics, cointerventions, occurrence of DCI, vital status after 6 months, neurological status after 6 months, hydroelectrolytic imbalances, and other SAH complication. Multivariable and sensitivity analyses that controlled for confounding and considered the presence of competing risks were used to adequately estimate the effects of the management protocol. The study was approved by our institutional ethics review board before study start.

RESULTS

One hundred eighty-nine patients were included for analysis. The management protocol was associated with a reduced incidence of DCI (hazard ratio 0.52 [95% confidence interval 0.33-0.83] from multivariable subdistribution hazards model) and hyponatremia (relative risk 0.55 [95% confidence interval 0.37-0.80]). The management protocol was not associated with higher hospital or long-term mortality, nor with a higher occurrence of other unfavorable outcomes (pulmonary edema, rebleeding, hydrocephalus, hypernatremia, pneumonia). The intervention group also had lower daily and cumulative administered fluids compared with historic controls (p < 0.0001).

CONCLUSIONS

A management protocol based on hemodynamically oriented fluid therapy in combination with a continuous albumin infusion as the main fluid during the first 5 days of the ICU stay appears beneficial for patients with SAH because it was associated with reduced incidence of DCI and hyponatremia. Proposed mechanisms include improved hemodynamic stability that allows euvolemia and reduces the risk of ischemia, among others.

Prevention and Correction of Dysnatremia After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Dysnatremia occurs commonly in patients with aneurysmal subarachnoid hemorrhage (aSAH). The mechanisms for development of sodium dyshomeostasis are complex, including the cerebral salt-wasting syndrome, the syndrome of inappropriate secretion of antidiuretic hormone, diabetes insipidus. Iatrogenic occurrence of altered sodium levels plays a role, as sodium homeostasis is tightly linked to fluid and volume management.

METHODS

Narrative review of the literature.

RESULTS

Many studies have aimed to identify factors predictive of the development of dysnatremia, but data on associations between dysnatremia and demographic and clinical variables are variable. Furthermore, although a clear relationship between serum sodium serum concentrations and outcomes has not been established-poor outcomes have been associated with both hyponatremia and hypernatremia in the immediate period following aSAH and set the basis for seeking interventions to correct dysnatremia. While sodium supplementation and mineralocorticoids are frequently administered to prevent or counter natriuresis and hyponatremia, evidence to date is insufficient to gauge the effect of such treatment on outcomes.

CONCLUSIONS

In this article, we reviewed available data and provide a practical interpretation of these data as a complement to the newly issued guidelines for management of aSAH. Gaps in knowledge and future directions are discussed.

Fluid Restriction Reduces Delayed Hyponatremia and Hospital Readmissions After Transsphenoidal Surgery

CONTEXT

Postoperative hyponatremia leads to prolonged hospital length of stay and readmission within 30 days.

OBJECTIVE

To assess 3 strategies for reducing rates of postoperative hyponatremia and analyze risk factors for hyponatremia.

DESIGN

Two retrospective analyses and 1 prospective study.

SETTING

Tertiary referral hospital.

PATIENTS

Patients undergoing transsphenoidal surgery for pituitary adenomas and other sellar and parasellar pathologies.

INTERVENTION(S)

Phase 1: no intervention. Phase 2: postoperative day (POD) 7 sodium testing and patient education. Phase 3: fluid restriction to 1 L/day on discharge in addition to phase 2 interventions.

MAIN OUTCOME MEASURES

Rates of early and delayed hyponatremia and readmissions. Secondary outcomes were risk factors for hyponatremia and readmission costs.

RESULTS

In phase 1, 296 patients underwent transsphenoidal surgery. Twenty percent developed early and 28% delayed hyponatremia. Thirty-eight percent underwent POD 7 sodium testing. Readmission rates were 15% overall and 4.3% for hyponatremia. In phase 2 (n = 316), 22% developed early and 25% delayed hyponatremia. Eighty-nine percent complied with POD 7 sodium testing. Readmissions were unchanged although severity of hyponatremia was reduced by 60%. In phase 3 (n = 110), delayed hyponatremia was reduced 2-fold [12.7%, relative risk (RR) = 0.52] and readmissions 3-fold [4.6%, RR = 0.30 (0.12-0.73)]; readmissions for hyponatremia were markedly reduced. Hyponatremia readmission increased costs by 30%.

CONCLUSIONS

Restricting fluid to 1 L/day on discharge decreases rates of delayed hyponatremia and readmissions by 50%. Standardized patient education and POD 7 sodium testing decreases severity of hyponatremia but does not impact readmission rates. These protocols should be considered standard practice for patients undergoing transsphenoidal surgery.

Postoperative free water administration is associated with dysnatremia after congenital heart disease surgery in infants

Dysnatremia after congenital heart disease (CHD) surgery is common. European guidelines on intraoperative fluid therapy in children recommend isotonic solutions to avoid hyponatremia, but prolonged cardiopulmonary bypass and administration of high sodium-containing solutions (i.e., blood products and sodium bicarbonate) are associated with postoperative hypernatremia. The aim of the study was to describe fluid composition prior to and during the development of postoperative dysnatremia. A retrospective observational, single-center study including infants undergoing CHD surgery. Demographics and clinical characteristics were registered. Highest and lowest plasma sodium values were recorded and associations with perioperative fluid administration, blood products, crystalloids, and colloids were explored in relation to three perioperative periods. Postoperative dysnatremia occurred in nearly 50% of infants within 48 h after surgery. Hypernatremia was mainly associated with administration of blood products (median [IQR]: 50.5 [28.4-95.5] vs. 34.5 [18.5-61.1] mL/kg; p = 0.001), and lower free water load (1.6 [1.1-2.2] mL/kg/h; p = 0.01). Hyponatremia was associated with a higher free water load (2.3 [1.7-3.3] vs. 1.8 [1.4-2.5] mL/kg/h; p = 0.001) and positive fluid balance. On postoperative day 1, hyponatremia was associated with higher volumes of free water (2.0 [1.5-2.8] vs. 1.3 [1.1-1.8] mL/kg/h; p < 0.001) and human albumin, despite a larger diuresis and more negative daily fluid balance. Postoperative hyponatremia occurred in 30% of infants despite restrictive volumes of hypotonic maintenance fluid, whereas hypernatremia was mainly associated with blood product transfusion. Individualized fluid therapy, with continuous reassessment to reduce the occurrence of postoperative dysnatremia is mandatory in pediatric cardiac surgery. Prospective studies to evaluate fluid therapy in pediatric cardiac surgery patients are warranted.

Marathon Runners' Knowledge and Strategies for Hydration

OBJECTIVE

To study hydration plans and understanding of exercise-associated hyponatremia (EAH) among current marathon runners.

DESIGN

Cross-sectional study.

SETTING

Southern California 2018 summer marathon.

PARTICIPANTS

Two hundred ten marathon runners.

INTERVENTIONS

Survey administered 1 to 2 days before the race. Race times were obtained from public race website.

MAIN OUTCOME MEASURES

Planned frequency of hydration; awareness of, understanding of, and preventative strategies for dehydration and EAH; resources used to create hydration plans; drink preferences.

RESULTS

When the participants were split into 3 equal groups by racing speed, the slower tertile intended to drink at every mile/station (60%), whereas the faster tertile preferred to drink every other mile or less often (60%), although not statistically significant. Most runners (84%) claimed awareness of EAH, but only 32% could list a symptom of the condition. Both experienced marathoners and the faster tertile significantly had greater understanding of hyponatremia compared with first-time marathoners and the slower tertile, respectively. Less than 5% of marathoners offered "drink to thirst" as a prevention strategy for dehydration or EAH.

CONCLUSION

Slower runners plan to drink larger volumes compared with their faster counterparts. Both slower and first-time marathoners significantly lacked understanding of EAH. These groups have plans and knowledge that may put them at higher risk for developing EAH. Most marathon runners did not know of the guidelines to "drink to thirst," suggesting the 2015 EAH Consensus statement may not have had the desired impact.

0.45% Versus 0.9% Saline in 5% Dextrose as Maintenance Fluids in Children Admitted With Acute Illness: A Randomized Control Trial

BACKGROUND

The safety of giving intravenous (IV) maintenance fluids according to Holliday and Segar's recommendations of 1957 has recently been questioned after reports of complications caused by iatrogenic hyponatremia in children receiving hypotonic fluids. However, the current practice of choice of maintenance IV fluids for hospitalized children varies worldwide. This study was planned to compare 0.45% and 0.9% saline in 5% dextrose at standard maintenance rates in hospitalized children aged 3 months to 12 years.

OBJECTIVE

Primary objective was to study change in serum sodium level at 24 hours in children receiving total IV fluid maintenance therapy as 0.45% or 0.9% normal saline in 5% dextrose. Secondary objectives of this study were to estimate change in serum sodium levels from the baseline to 48 or 72 hours, if IV fluids were continued, and to find incidence of hyponatremia and hypernatremia after administering these 2 types of maintenance fluids.

METHODS

This study was an open-label, randomized control trial conducted at the Department of Pediatrics of a tertiary care hospital from July 22, 2019, to October 28, 2019. Two hundred children aged 3 months to 12 years admitted in pediatric emergency and requiring IV maintenance fluid were randomized into 2 groups (group A received 0.45% saline in 5% dextrose, group B received 0.9% normal saline in 5% dextrose) with 100 in each group.

RESULTS

Both groups were comparable for baseline characteristics. Fall in mean serum sodium from baseline was more with increasing duration of IV fluids until 24 hours in 0.45% saline group as compared with 0.9% saline group, which was statistically significant (P < 0.001). The incidence of mild and moderate hyponatremia was significantly more in hypotonic group at 12 hours (P < 0.001) and 24 hours (P < 0.001). However, there was no significant difference at 48 hours.

CONCLUSIONS

The fall in serum sodium values was significant, and there was significant risk of hyponatremia with the use of hypotonic fluids at 12 and 24 hours. Hence, the use of isotonic fluids seems to be more appropriate among the hospitalized children.Trial Registration: CTRI/2019/10/021791.

Oleuropein Protects Against Cerebral Ischemia Injury in Rats: Molecular Docking, Biochemical and Histological Findings

This study was designed to evaluate the underlying protective mechanisms of oleuropein involved in alleviating brain damage in a rat model of ischemic stroke. Male Wistar rats were divided into four groups; Control, stroke (MCAO), MCAO + clopidogrel (Clop) and MCAO + oleuropein (Ole). Results showed that the MCAO group evidenced significant brain edema (+ 9%) as well as increases of plasma cardiac markers such as lactate deshydrogenase (LDH), creatine kinase (CK-MB), fibrinogen and Trop-T by 11 %, 43%, 168 and 590%, respectively, as compared to the control group. Moreover, infarcted rats exhibited remarkable elevated levels of angiotensin converting enzyme (ACE), both in plasma and brain tissue, with astrocyte swelling and necrotic neurons in the infarct zone, hyponatremia, and increased rate of thiobarbituric acid-reactive substances (TBARS) by 89% associated with decreases in the activity of superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (Cat) by 51%, 44 and 42%, respectively, compared to normal control rats. However, MCAO rats treated with oleuropein underwent mitigation of cerebral edema, correction of hyponatremia, remarkable decrease of plasma fibrinogen and cardiac dysfunctional enzymes, inhibition of ACE activity and improvement of oxidative stress status in brain tissue. Furthermore, in silico analysis showed considerable inhibitions of ACE, protein disulfide isomerase (PDI) and TGF-β1, an indicative of potent anti-embolic properties. Overall, oleuropein offers a neuroprotective effect against ischemic stroke through its antioxidative and antithrombotic activities.

Rehydration during Endurance Exercise: Challenges, Research, Options, Methods

During endurance exercise, two problems arise from disturbed fluid-electrolyte balance: dehydration and overhydration. The former involves water and sodium losses in sweat and urine that are incompletely replaced, whereas the latter involves excessive consumption and retention of dilute fluids. When experienced at low levels, both dehydration and overhydration have minor or no performance effects and symptoms of illness, but when experienced at moderate-to-severe levels they degrade exercise performance and/or may lead to hydration-related illnesses including hyponatremia (low serum sodium concentration). Therefore, the present review article presents (a) relevant research observations and consensus statements of professional organizations, (b) 5 rehydration methods in which pre-race planning ranges from no advanced action to determination of sweat rate during a field simulation, and (c) 9 rehydration recommendations that are relevant to endurance activities. With this information, each athlete can select the rehydration method that best allows her/him to achieve a hydration middle ground between dehydration and overhydration, to optimize physical performance, and reduce the risk of illness.

ENDOCRINOLOGY IN THE TIME OF COVID-19: Management of diabetes insipidus and hyponatraemia

COVID-19 has changed the nature of medical consultations, emphasizing virtual patient counseling, with relevance for patients with diabetes insipidus (DI) or hyponatraemia. The main complication of desmopressin treatment in DI is dilutional hyponatraemia. Since plasma sodium monitoring is not always possible in times of COVID-19, we recommend to delay the desmopressin dose once a week until aquaresis occurs allowing excess retained water to be excreted. Patients should measure their body weight daily. Patients with DI admitted to the hospital with COVID-19 have a high risk for mortality due to volume depletion. Specialists must supervise fluid replacement and dosing of desmopressin. Patients after pituitary surgery should drink to thirst and measure their body weight daily to early recognize the development of the postoperative syndrome of inappropriate antidiuresis (SIAD). They should know hyponatraemia symptoms. The prevalence of hyponatraemia in patients with pneumonia due to COVID-19 is not yet known, but seems to be low. In contrast, hypernatraemia may develop in COVID-19 patients in ICU, from different multifactorial reasons, for example, due to insensible water losses from pyrexia, increased respiration rate and use of diuretics. Hypernatraemic dehydration may contribute to the high risk of acute kidney injury in COVID-19. IV fluid replacement should be administered with caution in severe cases of COVID-19 because of the risk of pulmonary oedema.

Sodium Perturbations After Pituitary Surgery

Sodium perturbations are a common complication after pituitary surgery, with hyponatremia being the most frequent. Postoperative assessments should be tailored to the early and late periods, and monitoring sodium perturbations is recommended. Cerebral salt wasting is rare after pituitary surgery, and diagnosis and management can be challenging. Providing patient counseling and close postoperative follow-up is important to effectively manage diabetes insipidus and reduce hospital readmissions due to sodium perturbations.

Surgery within 48 hours in hip fractures in elderly patients exerts a positive effect on post-operative hyponatremia

This study investigated the prevalence of hyponatremia during the hospital stay, in a cohort of elderly patients with hip fractures who underwent surgery within 48 h from admission. Records data were retrieved from the database of the San Giovanni di Dio e Ruggi d'Aragona Hospital of Salerno, Italy. All elderly patients (≥65 years old) with a documented hip fracture that underwent surgery within 48 h from admission, between 2016 and 2018, were included and divided in 4 subgroups according to their sex and type of fracture. Serum sodium concentration were monitored during the hospital stay and collected at admission, before surgery, after surgery and at discharge. The overall prevalence of hyponatremia was 23.99% (n=71/295), (24.3%, n=57/234 for female patients and 22.9%, n=14/61 for male patients). The percentage of hyponatremic patients with an intracapsular hip fracture was 27.17% (n=25/92), and 22.66% (n=46/203) in patients with an extracapsular hip fracture. The highest value of mean serum sodium concentration (139.2 mmol/L±4.4 SD) was found at the hospital discharge phase, and the lowest value (138.4 mmol/L±4.3 SD) was found during the pre-surgery phase. The lowest mean value of serum sodium was found before surgery, while the highest was after surgery. This could suggest that the early operative treatment and the accurate in-hospital monitoring are effective to treat or prevent this condition.

Midodrine and albumin for prevention of complications in patients with cirrhosis awaiting liver transplantation. A randomized placebo-controlled trial

BACKGROUND & AIMS

Patients with decompensated cirrhosis on the waiting list for liver transplantation (LT) commonly develop complications that may preclude them from reaching LT. Circulatory dysfunction leading to effective arterial hypovolemia and activation of vasoconstrictor systems is a key factor in the pathophysiology of complications of cirrhosis. The aim of this study was to investigate whether treatment with midodrine, an alpha-adrenergic vasoconstrictor, together with intravenous albumin improves circulatory dysfunction and prevents complications of cirrhosis in patients awaiting LT.

METHODS

A multicenter, randomized, double-blind, placebo-controlled trial (NCT00839358) was conducted, including 196 consecutive patients with cirrhosis and ascites awaiting LT. Patients were randomly assigned to receive midodrine (15-30 mg/day) and albumin (40 g/15 days) or matching placebos for one year, until LT or drop-off from inclusion on the waiting list. The primary endpoint was incidence of any complication (renal failure, hyponatremia, infections, hepatic encephalopathy or gastrointestinal bleeding). Secondary endpoints were mortality, activity of endogenous vasoconstrictor systems and plasma cytokine levels.

RESULTS

There were no significant differences between both groups in the probability of developing complications of cirrhosis during follow-up (p = 0.402) or one-year mortality (p = 0.527). Treatment with midodrine and albumin was associated with a slight but significant decrease in plasma renin activity and aldosterone compared to placebo (renin -4.3 vs. 0.1 ng/ml.h, p < 0.001; aldosterone -38 vs. 6 ng/dl, p = 0.02, at week 48 vs. baseline). Plasma norepinephrine only decreased slightly at week 4. Neither arterial pressure nor plasma cytokine levels changed significantly.

CONCLUSIONS

In patients with cirrhosis awaiting LT, treatment with midodrine and albumin, at the doses used in this study, slightly suppressed the activity of vasoconstrictor systems, but did not prevent complications of cirrhosis or improve survival.

LAY SUMMARY

Patients with cirrhosis who are on the liver transplant waiting list often develop complications which prevent them from receiving a transplant. Circulatory dysfunction is a key factor behind a number of complications. This study was aimed at investigating whether treating patients with midodrine (a vasoconstrictor) and albumin would improve circulatory dysfunction and prevent complications. This combined treatment, at least at the doses administered in this study, did not prevent the complications of cirrhosis or improve the survival of these patients.

Strategies to reduce readmissions for hyponatremia after transsphenoidal surgery for pituitary adenomas

PURPOSE

Disorders of water balance, particularly hyponatremia from altered antidiuretic hormone (ADH) secretion, are a common post-operative complication of transsphenoidal surgery (TSS). We present our results from implementation of a 2-week 1.5 liter/daily fluid restriction on readmission rates for hyponatremia.

METHODS

A retrospective chart review was performed on 295 patients that underwent TSS for pituitary adenomas at the University of Colorado, between March 2014 and March 2017. Groups were divided into those before and after the implementation of a two-week, 1.5 liter daily fluid restriction and measurement of a serum sodium level 7 days (+/- 2 days) after discharge. A standard-of-care approach for variable degrees of hyponatremia was also utilized to guide hyponatremia management. Patient demographics, hospital course, post-operative complication rates, and rates of hospital admissions for hyponatremia were then evaluated.

RESULTS

Readmissions for symptomatic hyponatremia within 30 days of TSS occurred in 9 of 118 (7.6%) of patients prior to fluid restriction implementation and in four of 169 (2.4%) of patients in the post-implementation, fluid-restricted group (p-value = 0.04): a 70% reduction in hospitalizations. The two groups were similarly matched for pituitary tumor sub-type, age and gender. None of these factors were predictive for hyponatremia. Importantly, the mild fluid restriction did not result in any hospital readmissions for hypernatremia.

CONCLUSIONS

Mild fluid restriction (to 1.5 liters daily), in addition to a single post-operative serum sodium level, is an effective approach to preventing readmission for hyponatremia after TSS for pituitary adenomas.

A practical method for prevention of readmission for symptomatic hyponatremia following transsphenoidal surgery

INTRODUCTION

Patients undergoing transsphenoidal pituitary surgery (TSS) are at risk for several serious complications, including the syndrome of inappropriate antidiuretic hormone and subsequent hyponatremia.

OBJECTIVE

In this study, we examined the effect of 1 week of post-discharge fluid restriction to 1.0 L daily on rates of post-operative readmission for hyponatremia.

METHODS

We retrospectively analyzed all patients undergoing TSS from 2008 to 2014 and prospectively recorded patient data from 2015 to 2017. Patients were divided into a control cohort (2008-2014), who were discharged with instructions to drink to thirst; and an intervention cohort (2015-2017) who were instructed to drink less than 1.0 L daily for 1 week post-operatively.

RESULTS

This study included 788 patients; 585 (74.2%) in the control cohort and 203 (25.8%) in the intervention cohort. Overall, 436 (55.3%) were women, the median age was 47 (range 15-89), and average BMI was 29.4 kg/m² (range 17.7-101.7). Patients were relatively well matched. Of patients in the intervention group, none was readmitted for hyponatremia (0/203), compared to 3.41% (20/585) in the control group (p = 0.003). Patients in the intervention group also had significantly higher post-operative week one sodium levels (140.1 vs 137.5 mEq/L; p = 0.002). No fluid balance complications occurred in patients who followed this protocol.

CONCLUSION

Hyponatremia can be a life-threatening complication of TSS, and prevention of readmission for hyponatremia can help improve patient safety and decrease costs. Mandatory post-discharge fluid restriction is a simple and inexpensive intervention associated with decreased rates of readmission for hyponatremia and normal post-operative sodium levels.

Factors Associated with Pre-Event Hydration Status and Drinking Behavior of Middle-Aged Cyclists

OBJECTIVES

Water is an essential nutrient for thermoregulation, metabolism, cognition, and overall physiological homeostatic function. However, aging adults display a blunted thirst mechanism and subsequently have an increased risk for dehydration or hyponatremia. Fluid consumption behaviors are modifiable and the importance of practicing adequate drinking behaviors for aging adults is amplified during exercise. Identification of aging adult's hydration beliefs and how they attain hydration advice could provide valuable information into ways to promote better drinking habits to reduce fluid imbalances. Thus, this investigation evaluated the knowledge, beliefs and behaviors of middle-aged cyclists (MA) that were associated with hydration status and drinking behavior, before and during a 164-km mass-participation event (ambient temperature, 33.3±2.8ºC(mean±SD)).

DESIGN

This cross-sectional field study retrospectively grouped participants by their second urine specific gravity (Usg) measurement of the event morning prior to a mass participation cycling event. Usg was assessed via handheld refractometer.

SETTING

The Hotter N' Hell Hundred 164-km cycling event in Wichita Falls, Texas during the month of August.

PARTICIPANTS

36 male recreational cyclists (age, 53±9 y(mean±SD)).

MEASUREMENTS

Participants were grouped according their urine specific gravity as either slightly hyperhydrated (SH; n=12, Usg≤1.014), euhydrated (EUH; n=12, Usg, 1.015-1.020), or slightly dehydrated (SD; n=12, Usg≥1.021). Exercise histories and questionnaires were recorded 24-48 h prior to the cycling event.

RESULTS

Regardless of pre-event hydration status, all groups experienced a similar body mass loss during the 164-km event and finished with statistically similar exercise times; also, drinking behavior within all groups was influenced by multiple factors. The primary factors associated with MA cyclist drinking behavior were trial and error/personal history and thirst; further, the majority of cyclists (≥65%) in SH, EUH, and SD believed that dehydration affects performance negatively. The least important factors included rehydration recommendations from scientific and sports medicine organizations, plus information from sports drink manufacturers.

CONCLUSION

Considering the complexity of the present findings and the physiological changes that accompany aging such as delayed thirst perception, we recommend that MA cyclists formulate an individualized drinking plan that is based on observations during exercise.

Single-tubule RNA-Seq uncovers signaling mechanisms that defend against hyponatremia in SIADH

In the syndrome of inappropriate antidiuretic hormone secretion (SIADH), hyponatremia is limited by onset of vasopressin-escape caused by loss of the water channel aquaporin-2 in the renal collecting duct despite high circulating vasopressin. Here, we use the methods of systems biology in a well-established rat model of SIADH to identify signaling pathways activated at the onset of vasopressin-escape. Using single-tubule RNA-Seq, full transcriptomes were determined in microdissected cortical collecting ducts of vasopressin-treated rats at 1, 2, and 4 days after initiation of oral water loading in comparison to time-control rats without water loading. The time-dependent mRNA abundance changes were mapped to gene sets associated with curated canonical signaling pathways and revealed evidence of perturbation of transforming growth factor β signaling and epithelial-to-mesenchymal transition on Day 1 of water loading simultaneous with the initial fall in Aqp2 gene expression. On Day 2 of water loading, transcriptomic changes mapped to Notch signaling and the transition from G0 into the cell cycle but arrest at the G2/M stage. There was no evidence of cell proliferation or altered principal or intercalated cell numbers. Exposure of vasopressin-treated cultured mpkCCD cells to transforming growth factor β resulted in a virtually complete loss of aquaporin-2. Thus, there is a partial epithelial-to-mesenchymal transition during vasopressin escape with a subsequent shift from quiescence into the cell cycle with eventual arrest and loss of aquaporin-2.

Effects of Tolvaptan Addition to Furosemide in Normo- and Hyponatremia Patients with Heart Failure and Chronic Kidney Disease Stages G3b-5: A Subanalysis of the K-STAR Study

BACKGROUND

Tolvaptan increases free water clearance (aquaresis) and thereby improves hyponatremia. Although hyponatremia on admission is common in patients with congestive heart failure (CHF), little is known regarding the response to tolvaptan in those who also have chronic kidney disease (CKD) with or without hyponatremia. The aim of this subanalysis was to investigate the differences in treatment response between normo- and hyponatremia patients with CHF and CKD stages G3b-5.

METHODS

The Kanagawa Aquaresis Investigators Trial of Tolvaptan on HF Patients with Renal Impairment (K-STAR) was a multicenter, open-label, randomized, controlled prospective clinical trial that included 81 Japanese patients with CHF and residual signs of congestion despite oral furosemide treatment (≥40 mg/day). All patients were randomly assigned to 7-day treatment with either ≤15 mg/day of new add-on tolvaptan or ≤40 mg/day of increased furosemide. A subanalysis was conducted for 73 patients, who were classified into 2 groups according to their assigned treatment, then further stratified into 2 subgroups according to their serum sodium concentration [Na+]. The differences between the urine and serum parameters from day 1 to 3 were compared between the groups and between the subgroups in each group.

RESULTS

The change (Δ) in urine volume (ΔUV) and Δurine osmolality were greater in the tolvaptan group than in the furosemide group; however, ΔUV and Δurine osmolality did not show significant differences between the normonatremia subgroup and the hyponatremia subgroup in each group. In addition, Δserum [Na+] was greater in the tolvaptan group, although the change was not clinically significant. In contrast, Δserum [Na+] did not show significant differences between the normo- and hyponatremia subgroups in each group.

CONCLUSION

Tolvaptan added to furosemide resulted in a greater diuretic effect than increased furosemide, even in normonatremia patients with CHF complicated by CKD stages G3b-5 in the very early treatment phase.

Top 10 Research Questions Related to Preventing Sudden Death in Sport and Physical Activity

Participation in organized sport and recreational activities presents an innate risk for serious morbidity and mortality. Although death during sport or physical activity has many causes, advancements in sports medicine and evidence-based standards of care have allowed clinicians to prevent, recognize, and treat potentially fatal injuries more effectively. With the continual progress of research and technology, current standards of care are evolving to enhance patient outcomes. In this article, we provided 10 key questions related to the leading causes and treatment of sudden death in sport and physical activity, where future research will support safer participation for athletes and recreational enthusiasts. The current evidence indicates that most deaths can be avoided when proper strategies are in place to prevent occurrence or provide optimal care.

[Nephrogenic syndrome of inappropriate antidiuresis: Early diagnosis avoids severe hyponatremia complications]

AIM

Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is a rare disease characterized by a kidney disability to dilute urine and, as a result, severe recurrent hyponatremia. Due to wide variability in clinical expression, the diagnosis still remains a challenge for clinicians. We report our experience of a case in which NSIAD was diagnosed early. We also stress the importance of early diagnosis and treatment, which protects an infant with NSAID from severe hyponatremia.

BACKGROUND

A 1-month-old boy was referred to our hospital for persistent hyponatremia and intense vomiting. He was born full term after a normal pregnancy with a normal birth weight. The parents were healthy, nonconsanguineous, of Moroccan origin. They already had healthy twin girls. The physical examination was normal upon admission with no signs of dehydration and normal weight gain since birth. Plasma sodium was very low (125mmol/L) associated with low plasma urea (5mg/dL), osmolality (258 mOsm/kg) and low natriuresis (59mmol/L). These laboratory results suggested inappropriate antidiuretic hormone secretion (SIAD) and the infant was consequently treated with oral urea (he was already receiving sodium supplements that were later stopped). Due to exclusive breastfeeding, water restriction was impossible. Further biological investigation revealed undetectable plasma arginine vasopressin (AVP), suggesting the diagnosis of NSIAD. This was confirmed by genetic sequencing of the AVP receptor (AVPR2), demonstrating the presence of an R137C mutation.

CONCLUSIONS

We herein report a case of a genetic fluid balance disorder due to an activating mutation of AVPR2. NSIAD is an X-linked disease, first described in 2005 by Feldman et al., which involved severe recurrent hyponatremia. The very early diagnosis (at 7 weeks of life) and appropriate treatment with urea prevented seizures and cerebral damage due to severe recurrent hyponatremia. Clinicians should consider the diagnosis of NSIAD in infants with recurrent hyponatremia with hemodilution and low AVP serum level. Genetic analysis of the AVPR2 sequence on the X chromosome will confirm the diagnosis and, given the wide variability of clinical expression, sequencing of the family members should be done.

Management of delayed cerebral ischemia after subarachnoid hemorrhage

For patients who survive the initial bleeding event of a ruptured brain aneurysm, delayed cerebral ischemia (DCI) is one of the most important causes of mortality and poor neurological outcome. New insights in the last decade have led to an important paradigm shift in the understanding of DCI pathogenesis. Large-vessel cerebral vasospasm has been challenged as the sole causal mechanism; new hypotheses now focus on the early brain injury, microcirculatory dysfunction, impaired autoregulation, and spreading depolarization. Prevention of DCI primarily relies on nimodipine administration and optimization of blood volume and cardiac performance. Neurological monitoring is essential for early DCI detection and intervention. Serial clinical examination combined with intermittent transcranial Doppler ultrasonography and CT angiography (with or without perfusion) is the most commonly used monitoring paradigm, and usually suffices in good grade patients. By contrast, poor grade patients (WFNS grades 4 and 5) require more advanced monitoring because stupor and coma reduce sensitivity to the effects of ischemia. Greater reliance on CT perfusion imaging, continuous electroencephalography, and invasive brain multimodality monitoring are potential strategies to improve situational awareness as it relates to detecting DCI. Pharmacologically-induced hypertension combined with volume is the established first-line therapy for DCI; a good clinical response with reversal of the presenting deficit occurs in 70 % of patients. Medically refractory DCI, defined as failure to respond adequately to these measures, should trigger step-wise escalation of rescue therapy. Level 1 rescue therapy consists of cardiac output optimization, hemoglobin optimization, and endovascular intervention, including angioplasty and intra-arterial vasodilator infusion. In highly refractory cases, level 2 rescue therapies are also considered, none of which have been validated. This review provides an overview of current state-of-the-art care for DCI management.

Sodium measurement: effects of differing sampling and analytical methods

Background: It is recommended that children receiving intravenous fluids should have frequent biochemical monitoring, in some situations 4-6 hourly. Small changes in sodium must be detected, requiring very high precision from sodium analyses. Some children are monitored using venous blood analysed by indirect ion-selective electrode (ISE) interchangeably with capillary blood analysed by direct ISE. Our aim was to determine whether variability in sample collection together with variability in sodium measurement would lead to results which were unacceptable in the clinical setting.

Methods: Fifty-seven adults had capillary and venous blood analysed for sodium using direct ISE and venous plasma analysed for sodium using indirect ISE.

Results: Comparison of capillary blood analysed by direct ISE with venous plasma analysed by indirect ISE demonstrated wide scatter and poor correlation of results: r = 0.36, standard deviation (SD) of the differences 2.7 mmol/L and range of limits of agreement 10.6 mmol/L. Significant biases were observed comparing capillary blood sodium with venous plasma sodium ( P < 0.001), and comparing direct ISE with indirect ISE ( P < 0.001).

Conclusions: Venous plasma using indirect ISE and capillary blood with direct ISE cannot be used interchangeably to detect small changes in plasma sodium concentrations. To avoid misinterpretation of results when monitoring sodium over short time periods, the use of single methods of sampling and analysis must be strongly encouraged.