The pattern of plasma sodium abnormalities in an acute elderly care ward: A cross-sectional study

Approach to the Management of Hypernatraemia in Older Hospitalised Patients

Hypernatraemia is associated with high morbidity and mortality and is more common in patients of older age, nursing home residents and those with cognitive impairment and restricted mobility. The most common cause in hospital settings is water dehydration due to reduced intake although other causes should be identified. Once identified, prompt management is necessary to avoid delayed correction as prolonged hypernatremia is associated with increased hospital stay and mortality. Comprehensive history-taking and physical examination, basic investigations and medication review are essential to identify causative and remediable factors in those admitted with hypernatraemia. Accurate calculation of fluid deficit and ongoing losses is essential in order to ensure adequate fluid replacement, The administration of appropriate, usually hypotonic, fluids is also essential to the timely restoration of eunatraemia. Although evidence of definite harm resulting from rapid correction is lacking, a serum sodium reduction rate of <12 mmol/l day is advised with the caveat that close monitoring of electrolytes is required to ensure the desired correction rate is being achieved. Medical and nursing professionals should have access to a local hospital protocol to guide management of patients with hypernatraemia to improve patient outcomes and mitigate the risk of harm, particularly from under-recognition and slow correction.

Effect of the pretransplant serum sodium concentration on outcomes following liver transplantation

Hyponatremia is associated with an increased risk of mortality on the liver transplantation (LT) waiting list. Although the incorporation of the serum sodium (Na) level into the Model for End-Stage Liver Disease score may reduce wait-list mortality, concerns remain about a potential association between pre-LT hyponatremia and decreased post-LT survival. Furthermore, the relationship between pre-LT hypernatremia and post-LT survival remains unexplored. The purpose of this study was to investigate the impact of the entire spectrum of pre-LT serum Na levels on post-LT outcomes. We identified 19,537 patients from 2003 to 2010 for whom serum Na levels immediately before LT were available. The patients were divided into 3 groups [hyponatremic (Na ≤ 130 mEq/L), normonatremic (Na = 131-145 mEq/L), and hypernatremic (Na > 145 mEq/L)], and their post-LT outcomes were compared. There was no difference in in-hospital mortality or 90-day survival between patients with hyponatremia and patients with normonatremia. A fraction of the patients (2.4%) had hypernatremia, which was associated with increased in-hospital mortality (11.2% versus 4.2%, P < 0.001) and diminished 90-day survival (86.4% versus 94.0.%, P < 0.001). After adjustments for important clinical variables, the association of pre-LT hypernatremia with posttransplant mortality remained significant with a hazard ratio of 1.13 for each unit increase in the Na level > 145 mEq/L (P < 0.001). The duration of the hospitalization after LT was significantly longer for hypernatremic patients (P < 0.001). In conclusion, hyponatremia per se does not affect post-LT survival. Pre-LT hypernatremia is a highly significant risk factor for post-LT mortality.

Endothelial sodium channels trigger endothelial salt sensitivity with aging

The epithelial sodium channel is also expressed in vascular endothelium (endothelial sodium channel [EnNaC]). Depending on ambient sodium concentration, EnNaC is associated with mechanical stiffening of the endothelial cell cortex, leading to endothelial dysfunction. Because the incidence of both salt sensitivity and endothelial dysfunction increases with age, we investigated the abundance of EnNaC in aging mice. To assess EnNaC functionality and endothelial salt sensitivity, stiffness was measured while ambient sodium was varied. Aortae of young (3 months) and old (15 months) C57BL/6J wild-type mice were kept ex vivo on a physiological concentration of aldosterone (0.45 nmol/L). Spironolactone (10 nmol/L) and amiloride (1 μmol/L) were applied for aldosterone antagonism and EnNaC blockage, respectively. EnNaC at the endothelial cell surface was quantified by immunofluorescence staining. Cortical stiffness was monitored by atomic force microscopy when ambient sodium was raised from 135 to 150 mmol/L. In ex vivo aortae of older mice, endothelial cells had significantly higher EnNaC numbers than those of younger mice (+23%). In parallel, cortical stiffness was found increased (+8.5%). Acute application of high sodium led to an immediate rise in stiffness in both groups but was pronounced in endothelium of older mice (+18% versus +26%). Spironolactone and amiloride lowered EnNaC abundance and prevented endothelial stiffening under all conditions. We conclude that EnNaC mediates endothelial salt sensitivity in the aging process. This mechanism might contribute to the development of age-related cardiovascular disease and suggests the usage of spironolactone and amiloride specifically in the elderly.

Prevalence of hyponatremia on geriatric wards compared to other settings over four decades: a systematic review

Aim of the study was to analyze temporal trends in prevalence of hyponatremia over four decades in different settings. A systematic review of the literature from 1966 to 2009 yielded prevalences of hyponatremia, with standard errors (SE) and pooled estimated means (PEM), calculated by year and setting (geriatric, ICU, other hospital wards, psychiatric hospitals, nursing homes, outpatients). 53 studies were included. Prevalence of hyponatremia was stable from 1976 to 2006, and higher on geriatric wards accept for ICU: e.g. PEM prevalence of mild hyponatremia (serum sodium <135 mM) was 22.2% (95%CI 20.2-24.3) on geriatric wards, 6.0% (95%CI 5.9-6.1) on other hospital wards and 17.2% (SE 7.0) in one ICU-study; for severe hyponatremia (serum sodium<125 mM) these figures were 4.5% (95%CI 3.0-6.1), 0.8% (95%CI 0.7-0.8) and 10.3% (SE 5.6). In nursing homes PEM prevalence of mild hyponatremia was 18.8% (95%CI 15.6-22.2). The higher prevalence on geriatric wards could partly be explained by age-related changes in the regulation of serum sodium. Other underlying factors can be the presence of multiple diagnoses and the use of polypharmacy.

Does hypernatremia impact mortality in Toxic Epidermal Necrolysis?

Introduction: In-hospital hypernatremia is associated with increased mortality rates. We want to elucidate the impact of in-hospital acquired hypernatremia in mortality of Toxic Epidermal Necrolysis (TEN).

Purpose: Is there an association between hypernatremia and mortality in patients with TEN?

Method: Retrospective study of 25 patients with TEN. Laboratory electrolyte results, diuresis and survival were analyzed. Patients were separated in two groups without (Group A) or with (Group B) hypernatremia.

Results: In Group A 10 patients with a TBSA of 74±25% (mean ± standard deviation), and a SCORTEN-Score of 2.7±0.9 were summarized. Diuresis within the first 10 days after admission was 1±0.3 ml/kg/hour. In Group B 15 patients with a TBSA of 76±19%, and a SCORTEN-Score of 3.5±1 were included. Diuresis within the first 10 days after admission was 1.4±0.4 ml/kg/hour. Hypernatremia occurred on day 3.3±2.4 after admission and persisted for 5.3±2.9 days. Statistical analysis showed a significantly higher diuresis (p=0.007) and SCORTEN-Score (p=0.04) in the hypernatremic patients. One normonatremic and 8 hypernatremic patients died during ICU-stay (overall mortality rate 36%). A significantly higher mortality rate was found in Group B (odds ratio: 13,5; 95% confidence interval: 1.34–135.98; p=0.01) during ICU-stay.

Conclusion: TEN patients with an in-hospital acquired hypernatremia have an increased mortality risk. Close electrolyte monitoring is advisable in these patients.

Increased mortality in hypernatremic burned patients

Introduction: In-hospital hypernatremia develops usually iatrogenically from inadequate or inappropriate fluid prescription. In severely burned patient an extensive initial fluid resuscitation is necessary for burn shock survival. After recovering of cellular integrity the circulating volume has to be normalized. Hereby extensive water and electrolyte shifts can provoke hypernatremia.

Purpose: Is a hypernatremic state associated with increased mortality?

Method: Retrospective study for the incidence of hypernatremia and survival in 40 patients with a totally burned surface area (TBSA) >10%. Age, sex, TBSA, ABSI-Score and fluid resuscitation within the first 24 hours were analyzed. Patients were separated in two groups without (Group A) or with (Group B) hypernatremia.

Results: Hypernatremia occurred on day 5±1.4. No significant difference for age, sex, TBSA, ABSI-Score and fluid resuscitation within the first 24 hours were calculated. In Group A all patients survived, while 3 of the hypernatremic patient in Group B died during ICU-stay (Odds-ratio = 1.25; 95% CI 0.971–1.61; p=0.046).

Conclusion: Burned patients with an in-hospital acquired hypernatremia have an increased mortality risk. In case of a hypernatremic state early intervention is obligatory. There is a need of a fluid removal strategy in severely burned patient to avoid water imbalance.

Monitoring of drug-associated electrolyte disturbances in a hospital

PURPOSE

The aim of our study was to find drug-associated changes in serum levels of major electrolytes using clinical-event monitoring method.

METHODS

During 1-year period, electrolyte disturbances in serum samples from patients of Clinical Center Kragujevac, Serbia, were monitored in central biochemical facility. A sample of 982 patients was randomly selected from total population of 43,120 patients whose electrolyte serum levels were measured in the facility during the study period.

RESULTS

Clinically important drug-associated electrolyte disturbances were detected in 181 patient. There were 25 significant associations between the drugs and electrolyte values outside the reference range. However, only four causal connections were established: use of normal saline infusion with hypernatremia (OR 6.97, 95%CI 2.24-21.67), theophylline with acid-base disturbances (7.75, 1.46-41.02), polygeline infusion with decrease in bicarbonate levels (4.08, 1.42-11.73), and association of risperidone and hypocalcemia (4.10, 1.42-11.81).

CONCLUSION

Although clinical-event monitoring method is far from optimal, it could quantify the known risks and provide evidence for credible hypothesis of drug adverse reactions, based on both relevant biological pathways and reasonable clinical thinking, as it was the case in our study.

Serum sodium as a risk factor for in-hospital mortality in acute unselected general medical patients

BACKGROUND

Serum sodium has been shown to predict mortality in heart and liver failure.

AIM

To determine whether serum sodium independently predicts in-hospital mortality during any emergency medical admission.

DESIGN

An analysis was performed of all emergency medical patients admitted to St James's Hospital (SJH), Dublin between 1 January 2002 and 31 December 2006, using the hospital inpatient enquiry (HIPE) system, linked to the patient administration system and laboratory datasets. Hospital mortality was obtained from a database of 20 deaths occurring during the same period under physicians participating in the 'on call' roster.

METHODS

The serum sodium was determined at admission in all cases where it was deemed clinically necessary. Logistic regression was used to calculate crude and 25 adjusted odds ratios (ORs). Factors adjusted for included age, illness severity score (Modified Apache II score), major disease category, ICU stay, year effect, blood transfusion, gender and sepsis.

RESULTS

A total of 14 239 patients (47.5% male) were included in the analysis. Mortality had a U-shaped distribution and was highest in patients whose sodium level was <125 or >140 mmol/l. The unadjusted OR of death within 30 days of admission was 3.36 (95% CI 2.59-4.36) and 4.07 (95% CI 2.95-5.63) with sodium level <125 and >140 mmol/l, respectively. Adjustment for all of the factors above reduced the mortality odds in all hyponatraemia groups but all remained significant predictors of mortality. After adjustment for illness severity score the OR ratio for death in the >140 mmol/l group fell to 1.41 (95% CI 0.97-2.07).

DISCUSSION

The serum sodium is a powerful initial marker of likely mortality in unselected general medical patients. The increased death rate in hyponatraemic patients is independent of other clinical variables, whereas mortality in the hypernatraemic group is primarily a factor of illness severity.