Impact of diuretic therapy-associated electrolyte disorders present on admission to the emergency department: a cross-sectional analysis

BACKGROUND

Diuretics are among the most commonly prescribed medications and, due to their mechanisms of action, electrolyte disorders are common side effects of their use. In the present work we investigated the associations between diuretics being taken and the prevalence of electrolyte disorders on admission as well as the impact of electrolyte disorders on patient outcome.

METHODS

In this cross sectional analysis, all patients presenting between 1 January 2010 and 31 December 2011 to the emergency room (ER) of the Inselspital, University Hospital Bern, Switzerland were included. Data on diuretic medication, baseline characteristics and laboratory data including electrolytes and renal function parameters were obtained from all patients. A multivariable logistic regression model was performed to assess the impact of factors on electrolyte disorders and patient outcome.

RESULTS

A total of 8.5% of patients presenting to the ER used one diuretic, 2.5% two, and 0.4% three or four. In all, 4% had hyponatremia on admission and 12% hypernatremia. Hypokalemia was present in 11% and hyperkalemia in 4%. All forms of dysnatremia and dyskalemia were more common in patients taking diuretics. Loop diuretics were an independent risk factor for hypernatremia and hypokalemia, while thiazide diuretics were associated with the presence of hyponatremia and hypokalemia. In the Cox regression model, all forms of dysnatremia and dyskalemia were independent risk factors for in hospital mortality.

CONCLUSIONS

Existing diuretic treatment on admission to the ER was associated with an increased prevalence of electrolyte disorders. Diuretic therapy itself and disorders of serum sodium and potassium were risk factors for an adverse outcome.

Anti-LFA-1 or rapamycin overcome costimulation blockade-resistant rejection in sensitized bone marrow recipients

While costimulation blockade-based mixed chimerism protocols work well for inducing tolerance in rodents, translation to preclinical large animal/nonhuman primate models has been less successful. One recognized cause for these difficulties is the high frequency of alloreactive memory T cells (Tmem) found in the (pre)clinical setting as opposed to laboratory mice. In the present study, we therefore developed a murine bone marrow transplantation (BMT) model employing recipients harboring polyclonal donor-reactive Tmem without concomitant humoral sensitization. This model was then used to identify strategies to overcome this additional immune barrier. We found that B6 recipients that were enriched with 3 × 10(7) T cells isolated from B6 mice that had been previously grafted with Balb/c skin, rejected Balb/c BM despite costimulation blockade with anti-CD40L and CTLA4Ig (while recipients not enriched developed chimerism). Adjunctive short-term treatment of sensitized BMT recipients with rapamycin or anti-LFA-1 mAb was demonstrated to be effective in controlling Tmem in this model, leading to long-term mixed chimerism and donor-specific tolerance. Thus, rapamycin and anti-LFA-1 mAb are effective in overcoming the potent barrier that donor-reactive Tmem pose to the induction of mixed chimerism and tolerance despite costimulation blockade.

Hypercalcemia in the ED: prevalence, etiology, and outcome

PURPOSES

The aim of the study was to describe the prevalence, demographic, and clinical characteristics and etiologies of hypercalcemia in emergency department patients.

BASIC PROCEDURES

In this retrospective cross-sectional descriptive study, all patients admitted between April 1, 2008, and March 31, 2011, to the emergency department of Inselspital, University Hospital Bern, were screened for the presence of hypercalcemia, defined as a serum calcium exceeding 2.55 mmol/L after correction for serum albumin. Demographic, laboratory, and outcome data were gathered. A detailed medical record review was performed to identify causes of hypercalcemia.

MAIN FINDINGS

During the study period, 14 984 patients (19% of all admitted patients) received a measurement of serum calcium. Of these, 116 patients (0.7%) presented with hypercalcemia. Median serum calcium was 2.72 mmol/L (first quartile, 2.64; third quartile, 2.88), with 4.3 mmol/L being the maximum serum calcium value observed. Underlying malignancy in 44% of patients and hyperparathyroidism in 20% (12% secondary and 8% primary) were the leading causes of hypercalcemia. Twenty-six percent of patients presented with symptomatic hypercalcemia. Weakness was the most common symptom of hypercalcemia, followed by nausea and disorientation.

PRINCIPAL CONCLUSIONS

Hypercalcemia is a rare but harmful electrolyte disorder in emergency department patients. Unspecific symptoms such as a change in mental state, weakness, or gastrointestinal symptoms should prompt physicians to order serum calcium measurements, at least in patients with known malignancy or renal insufficiency.

Rising serum sodium levels are associated with a concurrent development of metabolic alkalosis in critically ill patients

PURPOSE

Changes in electrolyte homeostasis are important causes of acid-base disorders. While the effects of chloride are well studied, only little is known of the potential contributions of sodium to metabolic acid-base state. Thus, we investigated the effects of intensive care unit (ICU)-acquired hypernatremia on acid-base state.

METHODS

We included critically ill patients who developed hypernatremia, defined as a serum sodium concentration exceeding 149 mmol/L, after ICU admission in this retrospective study. Data on electrolyte and acid-base state in all included patients were gathered in order to analyze the effects of hypernatremia on metabolic acid-base state by use of the physical-chemical approach.

RESULTS

A total of 51 patients were included in the study. The time of rising serum sodium and hypernatremia was accompanied by metabolic alkalosis. A transient increase in total base excess (standard base excess from 0.1 to 5.5 mmol/L) paralleled by a transient increase in the base excess due to sodium (base excess sodium from 0.7 to 4.1 mmol/L) could be observed. The other determinants of metabolic acid-base state remained stable. The increase in base excess was accompanied by a slight increase in overall pH (from 7.392 to 7.429, standard base excess from 0.1 to 5.5 mmol/L).

CONCLUSIONS

Hypernatremia is accompanied by metabolic alkalosis and an increase in pH. Given the high prevalence of hypernatremia, especially in critically ill patients, hypernatremic alkalosis should be part of the differential diagnosis of metabolic acid-base disorders.

Modulation of the cellular redox status by the Alternaria toxins alternariol and alternariol monomethyl ether

The mycotoxin alternariol (AOH) has been reported to possess genotoxic properties, inducing enhanced levels of DNA damage after only 1 h of incubation. In the present study we addressed the question whether the induction of oxidative stress might contribute to the genotoxic effects of AOH or its naturally occurring monomethylether (AME). In the dichlorofluorescein (DCF) assay, treatment of HT29 cells for 1 h enhanced the formation of dichlorofluorescein, indicative for ROS formation. The total glutathione (tGSH) was transiently decreased. In accordance with the results of the DCF assay, AOH and AME enhanced the proportion of the transcription factor Nrf2 in the nucleus. Concomitantly, the Nrf2/ARE-dependent genes γ-glutamylcysteine ligase (γ-GCL) and glutathione-S-transferase (GSTA1/2) showed enhanced transcript levels. After 24 h of incubation this effect was also reflected on the protein level by an increase of GST activity. However, in spite of the positive DCF assay and the activation of the redox-sensitive Nrf2/ARE-pathway, the level of oxidative DNA damage, measured in the comet assay by the addition of formamidopyrimidine-DNA-glycosylase (fpg) remained unaffected. Of note, after 3 h of incubation no significant DNA damaging potential of AOH and AME was detectable, indicating either inactivation of the compounds or enhanced DNA repair. In summary, the mycotoxins AOH and AME were found to modulate the redox balance of HT29 cells but without apparent negative effect on DNA integrity.

Characteristics, symptoms, and outcome of severe dysnatremias present on hospital admission

OBJECTIVE

Dysnatremias are common in critically ill patients and associated with adverse outcomes, but their incidence, nature, and treatment rarely have been studied systematically in the population presenting to the emergency department. We conducted a study in patients presenting to the emergency department of the University of Bern.

METHODS

In this retrospective case series at a university hospital in Switzerland, 77,847 patients admitted to the emergency department between April 1, 2008, and March 31, 2011, were included. Serum sodium was measured in 43,911 of these patients. Severe hyponatremia was defined as less than 121 mmol/L, and severe hypernatremia was defined as less than 149 mmol/L.

RESULTS

Hypernatremia (sodium>145 mmol/L) was present in 2% of patients, and hyponatremia (sodium<135 mmol/L) was present in 10% of patients. A total of 74 patients had severe hypernatremia, and 168 patients had severe hyponatremia. Some 38% of patients with severe hypernatremia and 64% of patients with hyponatremia had neurologic symptoms. The occurrence of symptoms was related to the absolute elevation of serum sodium. Somnolence and disorientation were the leading symptoms in hypernatremic patients, and nausea, falls, and weakness were the leading symptoms in hyponatremic patients. The rate of correction did not differ between symptomatic and asymptomatic patients. Patients with symptomatic hypernatremia showed a further increase in serum sodium concentration during the first 24 hours after admission. Corrective measures were not taken in 18% of hypernatremic patients and 4% of hyponatremic patients.

CONCLUSIONS

Dysnatremias are common in the emergency department. Hyponatremia and hypernatremia have different symptoms. Contrary to recommendations, serum sodium is not corrected more rapidly in symptomatic patients.

Effect of coffee combining green coffee bean constituents with typical roasting products on the Nrf2/ARE pathway in vitro and in vivo

This study investigated Nrf2-activating properties of a coffee blend combining raw coffee bean constituents with 5-O-caffeoylquinic acid (CGA) as a lead component with typical roasting products such as N-methylpyridinium (NMP). In cell culture (HT29) the respective coffee extract (CN-CE) increased nuclear Nrf2 translocation and enhanced the transcription of ARE-dependent genes as exemplified for NAD(P)H:quinone oxidoreductase and glutathione-S-transferase (GST)A1, reflected in the protein level by an increase in GST enzyme activity. In a pilot human intervention study (29 healthy volunteers), daily consumption of 750 mL of CN-coffee for 4 weeks increased Nrf2 transcription in peripheral blood lymphocytes on average. However, the transcriptional response pattern of Nrf2/ARE-dependent genes showed substantial interindividual variations. The presence of SNPs in the Nrf2-promoter, reported recently, as well as the detection of GSTT1*0 (null) genotypes in the study collective strengthens the hypothesis that coffee acts as a modulator of Nrf2-dependent gene response in humans, but genetic polymorphisms play an important role in the individual response pattern.

Thyroid function and serum electrolytes: does an association really exist?

BACKGROUND

Thyroid hormone is a central regulator of body functions. Disorders of thyroid function are considered to be a cause of electrolyte disorders. Only few data on the association between thyroid function and electrolyte disorders exists.

METHODS

In the present retrospective analysis data from all patients admitted to the Department of Emergency Medicine of a university hospital who had measurements of thyroid function (TSH, fT(3), fT(4)) and electrolytes were included.

RESULTS

9,012 patients with measurement of TSH and electrolytes were available. 86% of patients had normal, 4% suppressed and 10% elevated TSH. Serum sodium was significantly lower in patients with high TSH levels (p <0.01). There was a significant correlation between serum TSH and phosphate level (p <0.05). Phosphate levels were higher in patients with elevated TSH than in patients with normal TSH (p <0.01). Serum calcium and magnesium correlated significantly with TSH (p <0.05). fT(3) levels correlated significantly with calcium (p <0.05). Hyponatraemia was present in 14% of patients with high TSH and was significantly more common than in the group with normal TSH levels of which 9% had hyponatraemia (p <0.01). Hypokalaemia was more common in the group with elevated TSH than in those with normal TSH (14 versus 11%, p = 0.016). Hyperkalaemia was more common in the group with high TSH levels (7%) than in those with normal TSH (7 vs. 4%, p <0.01).

CONCLUSION

An association between thyroid function and electrolyte disorders seems to exist, although it is probably only relevant in marked hypo-/hyperthyroidism.

An update on the current management of hyponatremia

Hyponatremia is the most common electrolyte disorder in hospitalized patients. According to the Edelman equation, hyponatremia usually develops due to a gain of free water, a loss of serum sodium or a combination of both. Investigating the causes of hyponatremia and consequent correction of the electrolyte disorder can be challenging. In this review we give an overview on the mechanisms leading to hyponatremia and in a further step, the correction of hyponatremia is discussed in detail with sections on: rate of correction, treatment with respect to volume state, risks of correction and a discussion of vasopressin receptor antagonists.

Acute hyponatremia after cardioplegia by histidine-tryptophane-ketoglutarate--a retrospective study

Background

Hyponatremia is the most common electrolyte disorder in hospitalized patients and is known to be associated with increased mortality. The administration of antegrade single-shot, up to two liters, histidine-tryptophane-ketoglutarate (HTK) solution for adequate electromechanical cardiac arrest and myocardial preservation during minimally invasive aortic valve replacement (MIAVR) is a standard procedure. We aimed to determine the impact of HTK infusion on electrolyte and acid–base balance.

Methods

In this retrospective analysis we reviewed data on patient characteristics, type of surgery, arterial blood gas analysis during surgery and intra-/postoperative laboratory results of patients receiving surgery for MIAVR at a large tertiary care university hospital.

Results

A total of 25 patients were included in the study. All patients were normonatremic at start of surgery. All patients developed hyponatremia after administration of HTK solution with a significant drop of serum sodium of 15 mmol/L (p < 0.01). Measured osmolality did not change during all times of surgery compared to start of surgery (p = 0.28 – p = 0.79), indicating isotonic hyponatremia. After administration of HTK solution pH fell significantly due to development of metabolic acidosis.

Conclusions

Acute hyponatremia during cardioplegia with HTK solution is isotonic and should probably not be corrected without presence of hypotonicity as confirmed by measurement of serum osmolality.

Electrolyte-free water clearance versus modified electrolyte-free water clearance: do the results justify the effort?

BACKGROUND

Calculation of electrolyte-free water clearance (EFWC) allows for quantification of renal losses of free water and was shown to be helpful in the differential diagnosis of dysnatremias and might help in the correction of the electrolyte disorders. A modified EFWC formula (MEFWC) was described to be more accurate than the conventional one; however, it has never been evaluated clinically.

METHODS

In order to evaluate the performance of MEFWC compared to EFWC under clinical circumstances, we gathered data from a total of 912 patient days of 138 critically ill patients. EFWC and MEFWC were calculated on the basis of these data. Additionally, from data of critically ill patients, we calculated a prediction of serum sodium based on the Edelman equation using either EFWC or MEFWC and compared results.

RESULTS

Altogether, 343 normonatremic, 124 hyponatremic and 445 hypernatremic days were analyzed. Results for EFWC and MEFWC correlated significantly (R = 0.98). In patients with hyponatremia, the absolute difference between EFWC and MEFWC was significantly larger than in patients with normonatremia (437 vs. 256 ml, p < 0.01). The absolute difference between EFWC and MEFWC correlated significantly with the level of serum sodium (R = -0.41). The mean difference in the prediction of serum sodium change as calculated based on the Edelman equation between the formula using EFWC and the formula using MEFWC was 0.7 mmol/l (SD 0.68) and was highest in hyponatremia and lowest in hypernatremia.

CONCLUSION

Results of EFWC and MEFWC were comparable in critically ill patients. Under normal circumstances, the use of the more complicated MEFWC is not justified. In hyponatremia, the difference between EFWC and MEFWC is larger and thus might justify the use of the more complicated formula.

["Truth at the bedside"]

BACKGROUND AND RESEARCH QUESTION

Discussions with seriously ill patients are part of physicians' tasks. These discussions are very demanding with respect to communication skills. In this paper we present the concept of an obligatory postgraduate course for physicians on breaking bad news and the results of the course evaluation.

RESEARCH PARTICIPANTS AND METHODS

Physicians of 4 German hospitals in which the module was offered as an obligatory inhouse course. An interventional study without control group was carried out in which a questionnaire (closed-ended questions and Likert scales as well as open-ended questions) was distributed before and immediately after the course.

RESULTS

186 physicians (response rate: 88.6 %) participated in the study. 102 respondents (54.8 %) had broken bad news more than five times per month. 75 physicians (40.3 %) indicated that they had never participated in a teaching module on this topic prior to the course. Discussions about the end of life and disclosure about recurrence of the disease were rated most frequently as very difficult communication situations. Compared with the beginning of the course the respondents rated their communication skills significantly better at the end of the course. The course's relevance for clinical practice, teaching methods and the organisation of the course were rated positively.

CONCLUSION

The feedback of the participants indicates the practical relevance of professional training on difficult communication situations such as breaking bad news. The improved rating of communication skills may be interpreted as a positive effect of the course. In our view, observational studies as well as interprofessional teaching modules contribute to improved professional communication with patients about diagnosis, prognosis and treatment options.

Observation and Characterization of the Pseudomorphic to Stable Phase Transitions of Fe1-xSi on Si(111)

Pseudomorphic Fe1-x Si films have been grown on Si(111) by molecular beam epitaxy (MBE) at room temperature (RT). Structural investigations revealed that the phase crystallizes in the cubic CsCl structure with a lattice constant close to half that of Si. Upon annealing, films thicker than 15Å undergo a phase transition to the stable bulk ε-FeSi, either in epitaxial or in polycrystalline form at temperatures around 300°C. Thinner films do not transform to the ε-FeSi phase. Instead they exhibit a continuous increase of the Si content up to the stoichiometry of FeSi2 The CsCl symmetry persists, exept for prolonged annealing close to the transition to βFeSi2, where γ-FeSi2 (CaF2 ) forms as an intermediate phase.