Influence of Early Dysnatremia Correction on Survival of Critically Ill Patients

Assessment of drug-induced electrolyte disorders in intensive care units: a multicenter observational study

Objective

Electrolyte disorder (ED) is frequently encountered critically ill patients during admission or admission to the intensive care unit (ICU). This study aimed to determine the frequency of ED encountered in ICU patients to evaluate the relationship of ED with drugs.

Methods

This prospective, multicenter study was conducted in the medical and anesthesiology ICUs of two training and research hospitals and included patients with at least one ED during admission or hospitalization in the ICUs. The relationship between ED and the drug was evaluated by calculating the logistic probabilistic method scale (LPMS) and the expert panel's evaluation. The correlation between EDs and LPMS was determined using Kendal tau. A binary logistic regression model was preferred in the analysis of factors related to ED. Statistical significance was set as p < 0.05.

Results

A total of 117 patients were included in the study. A total of 165 EDs were detected, including at least one in 88 (75.2%) patients. According to the expert panel, 61 (21.7%) of EDs were drug-related, whereas according to the LPMS, 111 (39.6%) (p < 0.001). Mortality (50% vs. 13.7%) and mechanical ventilation rates (52.2% vs. 17.2%) were significantly higher in patients with ED (p < 0.001). Patients with ED had 8.352 times higher odds of exhibiting mortality (OR: 8.352, %95 CI: 1.598-43.648, p: 0.012) and need mechanical ventilation with higher odds of 3.229 (OR: 3.229 95% CI: 0.815-12.787 p: 0.045). Patient who required enteral or parenteral feeding were associated with an increased likelihood of exhibiting ED (respectively OR: 30.057, %95 CI: 2.265-398.892, p: 0.01, OR: 5.537, %95 CI: 1.406-21.800, p: 0.014).

Conclusion

EDs are very common in the ICU. Dysnatremia was detected more commonly in other EDs. It has also been found that patients with ED are more often under mechanical ventilation, have more prolonged hospitalizations, and have higher mortality rates than patients without ED. The suitability of LPMS for assessing ED-drug relationships in the ICU context is questioned.

Dysnatremia at ICU admission and functional outcome of cardiac arrest: insights from four randomised controlled trials

PURPOSE

To evaluate the potential association between early dysnatremia and 6-month functional outcome after cardiac arrest.

METHODS

We pooled data from four randomised clinical trials in post-cardiac-arrest patients admitted to the ICU with coma after stable return of spontaneous circulation (ROSC). Admission natremia was categorised as normal (135-145 mmol/L), low, or high. We analysed associations between natremia category and Cerebral Performance Category (CPC) 1 or 2 at 6 months, with and without adjustment on the modified Cardiac Arrest Hospital Prognosis Score (mCAHP).

RESULTS

We included 1163 patients (581 from HYPERION, 352 from TTH48, 120 from COMACARE, and 110 from Xe-HYPOTHECA) with a mean age of 63 ± 13 years and a predominance of males (72.5%). A cardiac cause was identified in 63.6% of cases. Median time from collapse to ROSC was 20 [15-29] minutes. Overall, mean natremia on ICU admission was 137.5 ± 4.7 mmol/L; 211 (18.6%) and 31 (2.7%) patients had hyponatremia and hypernatremia, respectively. By univariate analysis, CPC 1 or 2 at 6 months was significantly less common in the group with hyponatremia (50/211 [24%] vs. 363/893 [41%]; P = 0.001); the mCAHP-adjusted odds ratio was 0.45 (95%CI 0.26-0.79, p = 0.005). The number of patients with hypernatremia was too small for a meaningful multivariable analysis.

CONCLUSIONS

Early hyponatremia was common in patients with ROSC after cardiac arrest and was associated with a poorer 6-month functional outcome. The mechanisms underlying this association remain to be elucidated in order to determine whether interventions targeting hyponatremia are worth investigating. Registration ClinicalTrial.gov, NCT01994772, November 2013, 21.

A retrospective cohort study on the clinical outcomes of patients admitted to intensive care units with dysnatremia

With evolving patient characteristics and patterns of ICU utilization, the impact of dysnatremias on patient outcomes and healthcare costs in the present era have not been well studied. Patients ≥ 18 years admitted to the ICUs in public hospitals in Hong Kong between January 2010 and June 2022 and had at least one serum sodium measurement obtained within 24 h prior to or following ICU admission were stratified into normonatremic (135-145 mmol/L), hyponatremic (< 135 mmol/L) and hypernatremic (> 145 mmol/L) groups. A total of 162,026 patients were included-9098 (5.6%), 40,533 (25.0%) and 112,395 (69.4%) patients were hypernatremic, hyponatremic and normonatremic at the time of ICU admission, respectively. The odds of patients with hypernatremia and hyponatremia dying in the ICU were 27% and 14% higher (aOR 1.27, 95% CI 1.19-1.36 and aOR 1.14, 95% CI 1.08-1.19, respectively; P < 0.001 for both), and 52% and 21% higher for dying in the hospital (aOR 1.52, 95% CI 1.43-1.62 and aOR 1.21, 95% CI 1.17-1.26, respectively; P < 0.001 for both] compared with those with normonatremia. Patients with dysnatremia also had longer ICU length of stay (LOS), hospital LOS, and higher healthcare costs than the normonatremic group. Dysnatremias at ICU admission were associated with increased ICU and in-hospital mortality and overall healthcare burden.

Effects of correction rate for severe hyponatremia in the intensive care unit on patient outcomes

PURPOSE

Limited evidence exists regarding outcomes associated with different correction rates of severe hyponatremia.

MATERIALS AND METHODS

This retrospective cohort analysis employed a multi-center ICU database to identify patients with sodium ≤120 mEq/L during ICU admission. We determined correction rates over the first 24 h and categorized them as rapid (> 8 mEq/L/day) or slow (≤ 8 mEq/L/day). The primary outcome was in-hospital mortality. Secondary outcomes included hospital-free days, ICU-free days, and neurological complications. We used inverse probability weighting for confounder adjustment.

RESULTS

Our cohort included 1024 patients; 451 rapid and 573 slow correctors. Rapid correction was associated with lower in-hospital mortality (absolute difference: -4.37%; 95% CI, -8.47 to -0.26%), longer hospital-free days (1.80 days; 95% CI, 0.82 to 2.79 days), and longer ICU-free days (1.16 days; 95% CI, 0.15 to 2.17 days). There was no significant difference in neurological complications (2.31%; 95% CI, -0.77 to 5.40%).

CONCLUSION

Rapid correction (>8 mEq/L/day) of severe hyponatremia within the first 24 h was associated with lower in-hospital mortality and longer ICU and hospital-free days without an increase in neurological complication. Despite major limitations, including the inability to identify the chronicity of hyponatremia, the results have important implications and warrant prospective studies.

Severe Hyponatremia Correction, Mortality, and Central Pontine Myelinolysis

BACKGROUND: In clinical practice, sodium correction rates are frequently limited in patients with severe hyponatremia to prevent neurologic complications. The implications of correction rates on overall mortality and length of hospital stay are unclear. METHODS: In this multicenter observational study, we evaluated the association of sodium correction rates with mortality, length of stay, and central pontine myelinolysis (CPM) in patients hospitalized with severe hyponatremia (admission serum sodium level less than 120 mEq/l). RESULTS: The cohort included 3274 patients. A correction rate of less than 6 mEq/l/24 hours was observed in 38%, 6 to 10 mEq/l/24 hours was observed in 29%, and greater than 10 mEq/l/24 hours was observed in 33%. Compared with 6 to 10 mEq/l/24 hours, a correction rate of less than 6 mEq/l/24 hours exhibited higher in-hospital mortality in multivariable-adjusted and propensity score–weighted analyses. Compared with 6 to 10 mEq/l/24 hours, a correction rate of greater than 10 mEq/l/24 hours was associated with lower in-hospital mortality and shorter length of stay in multivariable analyses. Seven patients with CPM were identified, with five of seven developing CPM despite a sodium correction rate of less than or equal to 8 mEq/l/24 hours. Six of seven patients who developed CPM had alcohol use disorder, malnutrition, hypokalemia, or hypophosphatemia. CONCLUSIONS: Limiting the sodium correction rate was associated with higher mortality and longer length of stay. Whether the sodium correction rate influences neurologic complications needs further evaluation.

Fluid balance control in critically ill patients: results from POINCARE-2 stepped wedge cluster-randomized trial

BACKGROUND

In critically ill patients, positive fluid balance is associated with excessive mortality. The POINCARE-2 trial aimed to assess the effectiveness of a fluid balance control strategy on mortality in critically ill patients.

METHODS

POINCARE-2 was a stepped wedge cluster open-label randomized controlled trial. We recruited critically ill patients in twelve volunteering intensive care units from nine French hospitals. Eligible patients were ≥ 18 years old, under mechanical ventilation, admitted to one of the 12 recruiting units for > 48 and ≤ 72 h, and had an expected length of stay after inclusion > 24 h. Recruitment started on May 2016 and ended on May 2019. Of 10,272 patients screened, 1361 met the inclusion criteria and 1353 completed follow-up. The POINCARE-2 strategy consisted of a daily weight-driven restriction of fluid intake, diuretics administration, and ultrafiltration in case of renal replacement therapy between Day 2 and Day 14 after admission. The primary outcome was 60-day all-cause mortality. We considered intention-to-treat analyses in cluster-randomized analyses (CRA) and in randomized before-and-after analyses (RBAA).

RESULTS

A total of 433 (643) patients in the strategy group and 472 (718) in the control group were included in the CRA (RBAA). In the CRA, mean (SD) age was 63.7 (14.1) versus 65.7 (14.3) years, and mean (SD) weight at admission was 78.5 (20.0) versus 79.4 (23.5) kg. A total of 129 (160) patients died in the strategy (control) group. Sixty-day mortality did not differ between groups [30.5%, 95% confidence interval (CI) 26.2-34.8 vs. 33.9%, 95% CI 29.6-38.2, p = 0.26]. Among safety outcomes, only hypernatremia was more frequent in the strategy group (5.3% vs. 2.3%, p = 0.01). The RBAA led to similar results.

CONCLUSION

The POINCARE-2 conservative strategy did not reduce mortality in critically ill patients. However, due to open-label and stepped wedge design, intention-to-treat analyses might not reflect actual exposure to this strategy, and further analyses might be required before completely discarding it. Trial registration POINCARE-2 trial was registered at ClinicalTrials.gov (NCT02765009). Registered 29 April 2016.

Trauma-related electrolyte disturbances: From resuscitation to rhabdomyolysis

Traumatic injury results in drastic changes to a patient's normal physiology. The hormonal stress response, as well as some treatment strategies, lead to significant disruptions in electrolyte homeostasis that are important for clinicians to understand. In addition, advances in fluid resuscitation and modern transfusion practices have led to their own unique set of consequences, which we are just beginning to appreciate. Special attention is placed on rhabdomyolysis, as this distinct entity represents an extreme example of injury induced electrolyte derangements. This review describes the physiologic response to trauma and highlights some of the important electrolyte abnormalities that can be encountered while caring for the injured patient.

Treatment of hyponatremia in children with acute bacterial meningitis

Purpose

Few studies have evaluated hyponatremia management in children with bacterial meningitis (BM). Thus, we aimed to describe variations in clinical practice, the effectiveness of sodium management, and adverse outcomes in children with BM and hyponatremia.

Methods

This retrospective cross-sectional study conducted at a tertiary institution analyzed participants' demographic, clinical, and sodium-altering treatment data. The sodium trigger for treatment was defined as pretreatment sodium level, with response and overcorrection defined as increments of ≥5 and &gt;10 mmol/L after 24 h, respectively.

Results

This study enrolled 364 children with BM (age: &lt;16 years; 215 boys). Hyponatremia occurred in 62.1% of patients, among whom 25.7% received sodium-altering therapies; 91.4% of those individuals had moderate/severe hyponatremia. Monotherapy was the most common initial hyponatremia treatment. After 24 h of treatment initiation, 82.4% of the patients responded. Logistic regression analyses revealed that ΔNa24 &lt;5 mmol/L [odds ratio (OR) 15.52, 95% CI 1.71–141.06, p = 0.015] and minimum Glasgow Coma Scale (GCS) score ≤ 8 (OR 11.09, 95% CI 1.16–105.73, p = 0.036) predicted dysnatremia at 48 h after treatment initiation. Although rare, persistent moderate/severe hyponatremia or hypernatremia at 48 h after treatment initiation was associated with a high mortality rate (57.1%).

Conclusion

This study found that most cases of hyponatremia responded well to various treatments. It is important to identify and institute appropriate treatment early for moderate or severe hyponatremia or hypernatremia in children with BM. This study was limited by its non-randomized nature.

Hypernatremia in Hospitalized Patients: A Large Population-Based Study

Background

Hypernatremia is a frequently encountered electrolyte disorder in hospitalized patients. Controversies still exist over the relationship between hypernatremia and its outcomes in hospitalized patients. This study examines the relationship of hypernatremia to outcomes among hospitalized patients and the extent to which this relationship varies by kidney function and age.

Methods

We conducted an observational study to investigate the association between hypernatremia, eGFR, and age at hospital admission and in-hospital mortality, and discharge dispositions. We analyzed the data of 1.9 million patients extracted from the Cerner Health Facts databases (2000-2018). Adjusted multinomial regression models were used to estimate the relationship of hypernatremia to outcomes of hospitalized patients.

Results

Of all hospitalized patients, 3% had serum sodium (Na) >145 mEq/L at hospital admission. Incidence of in-hospital mortality was 12% and 2% in hyper- and normonatremic patients, respectively. The risk of all outcomes increased significantly for Na >155 mEq/L compared with the reference interval of Na=135-145 mEq/L. Odds ratios (95% confidence intervals) for in-hospital mortality and discharge to a hospice or nursing facility were 34.41 (30.59-38.71), 21.14 (17.53-25.5), and 12.21 (10.95-13.61), respectively (all P<0.001). In adjusted models, we found that the association between Na and disposition was modified by eGFR (P<0.001) and by age (P<0.001). Sensitivity analyses were performed using the eGFR equation without race as a covariate, and the inferences did not substantially change. In all hypernatremic groups, patients aged 76-89 and ≥90 had higher odds of in-hospital mortality compared with younger patients (all P<0.001).

Conclusions

Hypernatremia was significantly associated with in-hospital mortality and discharge to a hospice or nursing facility. The risk of in-hospital mortality and other outcomes was highest among those with Na >155 mEq/L. This work demonstrates that hypernatremia is an important factor related to discharge disposition and supports the need to study whether protocolized treatment of hypernatremia improves outcomes.

The Prognostic Importance of Serum Sodium for Mortality among Critically Ill Patients Requiring Continuous Renal Replacement Therapy

BACKGROUND

Serum sodium derangement is common in critically ill patients requiring continuous renal replacement therapy (CRRT). We aimed to assess the association between serum sodium before and during CRRT with mortality.

METHODS

This is a historical cohort study of 1,520 critically ill patients receiving CRRT from December 2006 through November 2015 in a tertiary hospital in the United States. Using logistic regression analysis, we used serum sodium before CRRT, mean serum sodium, and serum sodium changes during CRRT to predict 90-day mortality after CRRT initiation.

RESULTS

Compared with the normal serum sodium levels, the odds ratio (OR) of 90-day mortality in patients with serum sodium before CRRT of 143-147 and ≥148 mmol/L were 1.45 (95% CI 1.03-2.05) and 2.24 (95% CI 1.33-3.87), respectively. There was no significant increase in 90-day mortality in serum sodium of ≤137 mmol/L. During CRRT, the mean serum sodium levels of ≤137 (OR 1.41; 95% CI 1.01-1.98) and ≥143 mmol/L (OR 1.52; 95% CI 1.14-2.03) were associated with higher 90-day mortality. The greater serum sodium changes during CRRT were associated with higher 90-mortality (OR 1.35; 95% CI 1.21-1.51 per 5-mmol/L increase).

CONCLUSION

Before CRRT initiation, hypernatremia and during CRRT, hypo- and hypernatremia were associated with increased mortality.

The prevalence and prognosis of hyponatraemia in non-Hodgkin lymphoma-associated hemophagocytic lymphohistiocytosis

Non-Hodgkin lymphoma associated hemophagocytic lymphohistiocytosis (NHL-HLH) in adult secondary HLH is a common and universally highly lethal critical disorder. Hyponatraemia is the most common electrolyte disorder in the critical illness setting and acts as a negative prognostic factor. The aim of our study was to evaluate the prognostic role of hyponatraemia among patients with NHL-HLH. The results showed that 81 (52.9%) patients had hyponatraemia. After a median follow up 47 (range 14-180) days, there were 72 (88.9%) cumulative deaths in hyponatraemia group while 50 (69.4%) in normonatremia group. After adjustment for confounders, multivariate analysis revealed that hyponatraemia was an independent prognostic factor for OS (HR:1.51, 95% CI: 1.03-2.20; p = 0.033). Restricted cubic spline confirmed a linear and positive association between serum sodium and the risk of mortality. Hyponatraemia is relatively frequent in NHL-HLH. As a readily available biomarker in clinical routine, it was a promising prognostic predictor for NHL-HLH.

Restoration of dysnatremia and acute kidney injury benefits outcomes of acute geriatric inpatients

Dysnatremia and dyskalemia are common problems in acutely hospitalized elderly patients. These disorders are associated with an increased risk of mortality and functional complications that often occur concomitantly with acute kidney injury in addition to multiple comorbidities. In a single-center prospective observational study, we recruited 401 acute geriatric inpatients. In-hospital outcomes included all-cause mortality, length of stay, and changes in functional status as determined by the Activities of Daily Living (ADL) scale, Eastern Cooperative Oncology Group (ECOG) performance, and Clinical Frailty Scale (CFS). The prevalence of dysnatremia alone, dyskalemia alone, and dysnatremia plus dyskalemia during initial hospitalization were 28.4%, 14.7% and 32.4%, respectively. Patients with electrolyte imbalance exhibited higher mortality rates and longer hospital stays than those without electrolyte imbalance. Those with initial dysnatremia, or dysnatremia plus dyskalemia were associated with worse ADL scores, ECOG performance and CFS scores at discharge. Subgroup analyses showed that resolution of dysnatremia was related to reduced mortality risk and improved CFS score, whereas recovery of renal function was associated with decreased mortality and better ECOG and CFS ratings. Our data suggest that restoration of initial dysnatremia and acute kidney injury during acute geriatric care may benefit in-hospital survival and functional status at discharge.

Increased short-term and long-term mortality in community- and hospital-acquired hypernatraemia and in patients with delayed serum sodium correction

BACKGROUND

This study examined the short-term and long-term mortality of community- and hospital-acquired hypernatraemia in a large cohort of general hospitalised patients, and the impact of delayed serum sodium correction in hypernatraemic patients.

METHODS

Adult patients admitted to Mayo Clinic Rochester from 2011 to 2013 were examined. The patients with admission serum sodium ≥138 mEq/L and at least 2 serum sodium measurements during hospitalisation were included. Hypernatraemia was defined as serum sodium ≥143 mEq/L. The patients were categorised into three groups based on serum sodium at admission and during hospitalisation: (a) normal serum sodium, (b) community-acquired hypernatraemia and (c) hospital-acquired hypernatraemia. Outcomes included hospital mortality and 1-year mortality after hospital discharge amongst hospital survivors.

RESULTS

Of 25 781 eligible patients, 45% had normal serum sodium, 20% had community-acquired hypernatraemia and 35% had hospital-acquired hypernatraemia. In adjusted analysis, odds ratios (ORs) of community- and hospital-acquired hypernatraemia for hospital mortality were 4.91 (95% CI 3.47-6.94) and 4.11 (95% CI 2.94-5.73), whereas hazard ratio (HR) for 1-year mortality was 1.76 (95% CI 1.56-1.98) and 1.61 (95% CI 1.45-1.79), respectively. Hospital-acquired hypernatraemia had a higher hospital mortality but not 1-year mortality than community-acquired hypernatraemia. In patients with community-acquired hypernatraemia, 36% remained hypernatraemic by hospital day 3. Hospital mortality (OR 3.01; 95% CI 2.71-5.83) and 1-year mortality (HR 1.51; 95% CI 1.26-1.81) were significantly increased in patients with persistent hypernatraemia, compared with those with serum sodium correction into optimal range of 138-142 mEq/L.

CONCLUSION

Hypernatraemia, regardless of acquisition origin, is associated with elevated short-term and long-term mortality. Hospital-acquired hypernatraemia was more common and had a higher short-term mortality than community-acquired hypernatraemia. Failure to correct hypernatraemia by hospital day 3 is associated with increased mortality.

Differential Inductive Sensing System for Truly Contactless Measuring of Liquids' Electromagnetic Properties in Tubing

Certain applications require a contactless measurement to eliminate the risk of sensor-induced sample contamination. Examples can be found in chemical process control, biotechnology or medical technology. For instance, in critically ill patients requiring renal replacement therapy, continuous in-line monitoring of blood conductivity as a measure for sodium should be considered. A differential inductive sensing system based on a differential transformer using a specific flow chamber has already proven suitable for this application. However, since the blood in renal replacement therapy is carried in plastic tubing, a direct measurement through the tubing offers a contactless method. Therefore, in this work we present a differential transformer for measuring directly through electrically non-conductive tubing by winding the tube around the ferrite core of the transformer. Here, the dependence of the winding type and the number of turns of the tubing on the sensitivity has been analyzed by using a mathematical model, simulations and experimental validation. A maximum sensitivity of 364.9 mV/mol/L is measured for radial winding around the core. A longitudinal winding turns out to be less effective with 92.8 mV/mol/L. However, the findings prove the ability to use the differential transformer as a truly contactless sensing system.

Association Between an Increase in Serum Sodium and In-Hospital Mortality in Critically Ill Patients

Supplemental Digital Content is available in the text.

OBJECTIVES:

In critically ill patients, dysnatremia is common, and in these patients, in-hospital mortality is higher. It remains unknown whether changes of serum sodium after ICU admission affect mortality, especially whether normalization of mild hyponatremia improves survival.

DESIGN:

Retrospective cohort study.

SETTING:

Ten Dutch ICUs between January 2011 and April 2017.

Patients:

Adult patients were included if at least one serum sodium measurement within 24 hours of ICU admission and at least one serum sodium measurement 24–48 hours after ICU admission were available.

INTERVENTIONS:

None.

MEASUREMENTS AND MAIN RESULTS:

A logistic regression model adjusted for age, sex, and Acute Physiology and Chronic Health Evaluation-IV–predicted mortality was used to assess the difference between mean of sodium measurements 24–48 hours after ICU admission and first serum sodium measurement at ICU admission (Δ48 hr-[Na]) and in-hospital mortality. In total, 36,660 patients were included for analysis. An increase in serum sodium was independently associated with a higher risk of in-hospital mortality in patients admitted with normonatremia (Δ48 hr-[Na] 5–10 mmol/L odds ratio: 1.61 [1.44–1.79], Δ48 hr-[Na] > 10 mmol/L odds ratio: 4.10 [3.20–5.24]) and hypernatremia (Δ48 hr-[Na] 5–10 mmol/L odds ratio: 1.47 [1.02–2.14], Δ48 hr-[Na] > 10 mmol/L odds ratio: 8.46 [3.31–21.64]). In patients admitted with mild hyponatremia and Δ48 hr-[Na] greater than 5 mmol/L, no significant difference in hospital mortality was found (odds ratio, 1.11 [0.99–1.25]).

CONCLUSIONS:

An increase in serum sodium in the first 48 hours of ICU admission was associated with higher in-hospital mortality in patients admitted with normonatremia and in patients admitted with hypernatremia.

Crystalloid and Colloid Compositions and Their Impact

This manuscript will review crystalloid (hypo-, iso-, and hyper-tonic) and colloid (synthetic and natural) fluids that are available for intravenous administration with a focus on their electrolyte, acid-base, colligative, and rheological effects as they relate to each solution's efficacy and safety. The goal is for the reader to better understand the differences between each fluid and the influence on plasma composition, key organ systems, and their implications when used therapeutically in animals with critical illness.

How Geometry Affects Sensitivity of a Differential Transformer for Contactless Characterization of Liquids

The electrical and dielectric properties of liquids can be used for sensing. Specific applications, e.g., the continuous in-line monitoring of blood conductivity as a measure of the sodium concentration during dialysis treatment, require contactless measuring methods to avoid any contamination of the medium. The differential transformer is one promising approach for such applications, since its principle is based on a contactless, magnetically induced conductivity measurement. The objective of this work is to investigate the impact of the geometric parameters of the sample or medium under test on the sensitivity and the noise of the differential transformer to derive design rules for an optimized setup. By fundamental investigations, an equation for the field penetration depth of a differential transformer is derived. Furthermore, it is found that increasing height and radius of the medium is accompanied by an enhancement in sensitivity and precision.

Electrolyte disorders during the initiation of nutrition therapy in the ICU

PURPOSE OF REVIEW

To summarize recent evidence on prevalence, risk factors, significance, treatment, and prevention of electrolyte disorders in critically ill with a specific focus on disorders during the initiation of nutrition.

RECENT FINDINGS

Electrolyte disturbances appear to occur often during critical illness, and most of them seem to be associated with impaired outcome. However, a recent systematic review indicated insufficient evidence to answer clinically relevant questions regarding hypophosphatemia. Similar questions (which thresholds of serum levels are clinically relevant; how serum levels should be corrected and how do different correction regimens/approaches influence outcome) are not clearly answered also for other electrolytes. The most crucial feature of electrolyte disturbances related to feeding is refeeding syndrome. Recent evidence supports that additionally to the correction of electrolyte levels, a temporary restriction of calories (reducing the magnitude of this metabolic feature, including electrolyte shifts) may help to improve outcome.

SUMMARY

Diverse electrolyte disorders often occur in critically ill patients. Hypophosphatemia, hypokalemia, and hypomagnesemia that are encountered after initiation of feeding identify refeeding syndrome. Along with correction of electrolytes, reduction of caloric intake may improve the outcome of the refeeding syndrome.

Significance of Hypernatremia Due to SARS-CoV-2 Associated ARDS in Critically Ill Patients

Background and Objectives

SARS-CoV-2-induced ARDS is a new entity that should be characterized as it appears to be different from standard ARDS. Hypernatremia is a biological alteration that seems to occur very often in this population without any clear cause. The present study aims to clarify the possible causes of hypernatremia and evaluate its impact on patient outcome.

Patients and Methods

We conducted a retrospective one-day prevalence study in 2 intensive care units, which only treated COVID-19 patients with moderate to severe ARDS. We measured blood and urine electrolytes in all the patients. Patients with chronic renal failure or renal replacement therapy were excluded from the study. Hypernatremia was defined as plasma sodium levels above 145 mmol/L.

Results

Inclusion criteria were met in 17 out of 24 patients. Hypernatremia was present in 52% patients. All had a natriuresis higher than 20 mmol/L and a urine osmolality above 600 mOsm/L. Hypernatremia was acquired in ICU as all the patients had a normal serum sodium level at admission.

Conclusion

The incidence of hypernatremia was elevated and appears to be linked to significant insensible water losses. This should trigger us to optimize the maintenance fluid therapy in critically ill patients with SARS-CoV-2-induced ARDS.

Determinants of serum magnesium abnormalities and outcome among admissions to the intensive care unit

Serum magnesium is a frequently measured and treated electrolyte. However, few studies have examined magnesium level abnormalities and outcome in critically ill patients. Our objective was to determine the epidemiology and outcome of magnesium abnormalities among patients admitted to intensive care units (ICU). A retrospective cohort including adult patients admitted to three ICUs in southeast Queensland was assembled. Magnesium levels < 0.7, 0.7-1.0, and > 1.0 mmol/L were classified as low, normal, and high, respectively. Among 14,101 patients, the median age was 59.3 (interquartile range; IQR, 45.1-70.5), 7493 (56.4%) were male, and the median APACHE III score was 48 (IQR, 34-66). At admission, 3357 (23.8%) patients were classified as having hypomagnesemia, 1682 (11.9%) hypermagnesemia, 165 (1.2%) mixed, and 8897 (63.1%) as normal. Patients with magnesium abnormalities were more likely to be underweight and to have higher APACHE III scores. The overall 30-day case fatality was 8.2% (1155/14,101). Compared to those with normal levels, patients with hypermagnesemia at admission were at two-fold increased crude risk for death (relative risk; RR, 2.09; 95% confidence interval; CI, 1.83-2.39; p < 0.0001). After controlling for confounding variables in logistic regression analysis, neither admission hypo- nor hypermagnesemia was associated with death. However, development of ICU acquired hypermagnesemia among those with normal (odds ratio; OR, 1.34; 95% CI, 1.02-1.77; p = 0.034) and low (OR, 1.67; 95% CI, 1.15-2.41; p = 0.006) admission magnesium levels increased the risk for death. Magnesium abnormalities are common among patients managed in ICUs. The determinants of ICU-acquired hypermagnesemia and its adverse effect on outcome warrants further investigation.

Sodium Abnormalities in Cardiac Surgery With Cardiopulmonary Bypass in Adults: A Narrative Review

Perioperative sodium abnormalities or dysnatremia is not uncommon in patients presenting for cardiac surgery and is associated with increased morbidity and mortality. Both the disease process of heart failure and its treatment may contribute to abnormalities in serum sodium concentration. Serum sodium is the main determinant of serum osmolality, which in turn affects cell volume. Brain cells are particularly vulnerable to changes in serum osmolality because of the nondistensible cranium. The potentially catastrophic neurologic sequelae of rapidly correcting chronic dysnatremia and the time-sensitive nature of cardiac surgery can make the management of these patients challenging. The use of cardiopulmonary bypass to facilitate surgery adds another layer of complexity in the intraoperative management of sodium and water balance. This narrative review examines the definition and classification of dysnatremia. It also covers the etiology and pathophysiology of dysnatremia, implications during cardiac surgery requiring cardiopulmonary bypass, and the perioperative management of dysnatremia.

Abnormal Serum Sodium is Associated With Increased Mortality Among Unselected Cardiac Intensive Care Unit Patients

Background

Abnormal serum sodium levels have been associated with higher mortality among patients with acute coronary syndromes and heart failure. We sought to describe the association between sodium levels and mortality among unselected cardiac intensive care unit (CICU) patients.

Methods and Results

We retrospectively reviewed consecutive adult patients admitted to our cardiac intensive care unit from 2007 to 2015. Hyponatremia and hypernatremia were defined as admission serum sodium <135 and >145 mEq/L, respectively. In‐hospital mortality was assessed by multivariable regression, and postdischarge mortality was evaluated by Cox proportional‐hazards analysis. We included 9676 patients with a mean age of 68±15 years (37.5% females). Hyponatremia occurred in 1706 (17.6%) patients, and hypernatremia occurred in 322 (3.3%) patients; these groups had higher illness severity and a greater number of comorbidities. Risk of hospital mortality was higher with hyponatremia (15.5% versus 7.5%; unadjusted odds ratio, 2.41; 95% CI, 2.06–2.82; P<0.001) or hypernatremia (17.7% versus 8.6%; unadjusted odds ratio, 2.82; 95% CI, 2.09–3.80; P<0.001), with a J‐shaped relationship between admission sodium and mortality. After multivariate adjustment, only hyponatremia was significantly associated with in‐hospital mortality (adjusted odds ratio, 1.42; 95% CI, 1.14–1.76; P=0.002). Among hospital survivors, risk of postdischarge mortality was higher in patients with hyponatremia (adjusted hazard ratio, 1.28; 95% CI, 1.17–1.41; P<0.001) or hypernatremia (adjusted hazard ratio, 1.36; 95% CI, 1.12–1.64; P=0.002).

Conclusions

Hyponatremia and hypernatremia on admission to the cardiac intensive care unit are associated with increased unadjusted short‐ and long‐term mortality. Further studies are needed to determine whether correcting abnormal sodium levels can improve outcomes in cardiac intensive care unit patients.

Influence of dyskalemia at admission and early dyskalemia correction on survival and cardiac events of critically ill patients

Objectives

Our objectives were (1) to characterize the distribution of serum potassium levels at ICU admission, (2) to examine the relationship between dyskalemia at ICU admission and occurrence of cardiac events, and (3) to study both the association between dyskalemia at ICU admission and dyskalemia correction by day 2 on 28-day mortality.

Design

Inception cohort study from the longitudinal prospective French multicenter OUTCOMEREA database (1999–2014)

Setting

22 French OUTCOMEREA network ICUs

Patients

Patients were classified into six groups according to their serum potassium level at admission: three groups of hypokalemia and three groups of hyperkalemia defined as serious hypokalemia [K+] < 2.5 and serious hyperkalemia [K+] > 7 mmol/L, moderate hypokalemia 2.5 ≤ [K+] < 3 mmol/L and moderate hyperkalemia 6 < [K+] ≤ 7 mmol/L, and mild hypokalemia 3 ≤ [K+] < 3.5 mmol/L and mild hyperkalemia 5 < [K+] ≤ 6 mmol/L. We sorted evolution at day 2 of dyskalemia into three categories: balanced, not-balanced, and overbalanced.

Intervention

None

Measurements and main results

Of 12,090 patients, 2108 (17.4%) had hypokalemia and 1445 (12%) had hyperkalemia.

Prognostic impact of dyskalemia and its correction was assessed using multivariate Cox models. After adjustment, hypokalemia and hyperkalemia were independently associated with a greater risk of 28-day mortality. Mild hyperkalemic patients had the highest mortality (hazard ratio (HR) 1.29, 95% confidence interval (CI) [1.13–1.47], p < 0.001). Adjusted 28-day mortality was higher if serum potassium level was not-balanced at day 2 (aHR = 1.51, 95% CI [1.30–1.76], p < 0.0001) and numerically higher but not significantly different if serum potassium level was overbalanced at day 2 (aHR = 1.157, 95% CI [0.84–1.60], p = 0.38). Occurrence of cardiac events was evaluated by logistic regression. Except for patients with serious hypokalemia at admission, the depth of dyskalemia was associated with increased risk of cardiac events.

Conclusions

Dyskalemia is common at ICU admission and associated with increased mortality. Occurrence of cardiac events increased with dyskalemia depth. A correction of serum potassium level by day 2 was associated with improved prognosis.

Acute Dysnatremias - a dangerous and overlooked clinical problem

Background

Dysnatremias are common electrolyte disturbances with significant morbidity and mortality. In chronic dysnatremias a slow correction rate (<10 mmol/L/24 h) is indicated to avoid neurological complications. In acute dysnatremias (occurring <48 h) a rapid correction rate may be indicated. Most guidelines do not differ between acute and chronic dysnatremias. In this review, we focus on the evidence-based treatment of acute dysnatremias.

Methods

A literary search in PubMed and Embase. A total of 72 articles containing 79 cases were included, of which 12 cases were excluded due to lack of information.

Results

Of 67 patients (70% women) with acute dysnatremia, 60 had hypo- and 7 had hypernatremia. All patients with hyper- and 88% with hyponatremia had a rapid correction rate (> 10 mmol/L/24 h). The median time of correction was 1 day in patients with hypo- and 2.5 days in patients with hypernatremia. The mortality was 7% in patients with hypo- and 29% in patients with hypernatremia.

Interpretation

Severe acute dysnatremias have significant mortality and require immediate treatment. A rapid correction rate may be lifesaving and is not associated with neurological complications. Chronic dysnatremias, on the other hand, are often compensated and thus less severe. In these cases a rapid correction rate may lead to severe cerebral complications.

Electronic supplementary material

The online version of this article (10.1186/s13049-019-0633-3) contains supplementary material, which is available to authorized users.

A novel scoring system for assessing the severity of electrolyte and acid-base disorders and predicting outcomes in hospitalized patients

Electrolyte and acid-base disorders are commonly seen in critically ill and other hospitalized patients. A scoring system is needed to assess the severity of electrolyte and acid-base disorders and to predict outcome in hospital patients. Herein, we prospectively enrolled a total of 322,046 patients, including 84,700 patients in the derivation cohort and 237,346 in the validation cohort, in a large, tertiary hospital in East China from 2014 to 2017. A points-scoring system of general electrolyte and acid-base disorders with a sum of 20.8 points was generated by multiple logistic regression analysis of the derivation cohort. Receiver operating characteristic curve analysis showed that the optimal cut-off value of 2.0 was associated with 65.4% sensitivity and 88.4% specificity (area under the curve: 0.818 (95% CI 0.809 to 0.827)) to predict hospital mortality in the validation cohort. On Kaplan-Meier survival analysis, the five intervals of risk score (Q1: 0 to 2.0; Q2: 2.1 to 2.5; Q3: 2.6 to 3.3; Q4: 3.4 to 4.5; and Q5: >4.5 points) showed differences in hospital survival (p<0.001). Elevated (delta) risk score >2 during hospitalization increased the risk of hospital death, while those with a delta risk score <0 and <−2 points had higher survival rates. This novel scoring system could be used to evaluate and to dynamically monitor the severity of electrolyte and acid-base disorders in hospitalized patients.

Does Fluid Type and Amount Affect Kidney Function in Critical Illness?

Acute kidney injury (AKI) is common, although commonly used clinical diagnostic markers are imperfect. Intravenous fluid administration remains a cornerstone of therapy worldwide, but there is minimal evidence of efficacy for the use of fluid bolus therapy outside of specific circumstances, and emerging evidence associates fluid accumulation with worse renal outcomes and even increased mortality among critically ill patients. Artificial colloid solutions have been associated with harm, and chloride-rich solutions may adversely affect renal function. Large trials to provide guidance regarding the optimal fluid choices to prevent or ameliorate AKI, and promote renal recovery, are urgently required.

Hospital-Associated Hypernatremia Spectrum and Clinical Outcomes in an Unselected Cohort

BACKGROUND

Although hypernatremia is associated with adverse outcomes, most studies examined selected populations.

METHODS

Discharge data of 19,072 unselected hospitalized adults were analyzed. The crude relationship between serum sodium [Na⁺] and mortality defined hypernatremia as serum [Na⁺] >142 mEq/L. Patients with community-acquired hypernatremia or hospital-acquired hypernatremia were compared with normonatremic patients (admission [Na⁺] 138-142 mEq/L) regarding in-hospital mortality, length of stay, and discharge disposition. Patients with community-acquired hypernatremia whose hypernatremia worsened during hospitalization were compared with those without aggravation.

RESULTS

Community-acquired hypernatremia occurred in 21% of hospitalized patients and was associated with an adjusted odds ratio (OR) of 1.67 (95% confidence interval [CI], 1.38-2.01) for in-hospital mortality and 1.44 (95% CI, 1.32-1.56) for discharge to a short-/long-term care facility and an adjusted 10% (95% CI, 7-13) increase in length of stay. Hospital-acquired hypernatremia developed in 25.9% of hospitalized patients and was associated with an adjusted OR of 3.17 (95% CI, 2.45-4.09) for in-hospital mortality and 1.45 (95% CI, 1.32-1.59) for discharge to a facility, and an adjusted 49% (95% CI, 44-53) increase in length of stay. Hospital-aggravated hypernatremia developed in 11.7% of patients with community-acquired hypernatremia and was associated with greater risk of in-hospital mortality (adjusted OR, 1.84; 95% CI, 1.32-2.56) and discharge to a facility (adjusted OR, 2.14; 95% CI, 1.71-2.69), and an adjusted 16% (95% CI, 7-27) increase in length of stay.

CONCLUSIONS

The hypernatremia spectrum in unselected hospitalized patients is independently associated with increased in-hospital mortality and heightened resource consumption.

Association between continuous hyperosmolar therapy and survival in patients with traumatic brain injury - a multicentre prospective cohort study and systematic review

BACKGROUND

Intracranial hypertension (ICH) is a major cause of death after traumatic brain injury (TBI). Continuous hyperosmolar therapy (CHT) has been proposed for the treatment of ICH, but its effectiveness is controversial. We compared the mortality and outcomes in patients with TBI with ICH treated or not with CHT.

METHODS

We included patients with TBI (Glasgow Coma Scale ≤ 12 and trauma-associated lesion on brain computed tomography (CT) scan) from the databases of the prospective multicentre trials Corti-TC, BI-VILI and ATLANREA. CHT consisted of an intravenous infusion of NaCl 20% for 24 hours or more. The primary outcome was the risk of survival at day 90, adjusted for predefined covariates and baseline differences, allowing us to reduce the bias resulting from confounding factors in observational studies. A systematic review was conducted including studies published from 1966 to December 2016.

RESULTS

Among the 1086 included patients, 545 (51.7%) developed ICH (143 treated and 402 not treated with CHT). In patients with ICH, the relative risk of survival at day 90 with CHT was 1.43 (95% CI, 0.99-2.06, p = 0.05). The adjusted hazard ratio for survival was 1.74 (95% CI, 1.36-2.23, p < 0.001) in propensity-score-adjusted analysis. At day 90, favourable outcomes (Glasgow Outcome Scale 4-5) occurred in 45.2% of treated patients with ICH and in 35.8% of patients with ICH not treated with CHT (p = 0.06). A review of the literature including 1304 patients from eight studies suggests that CHT is associated with a reduction of in-ICU mortality (intervention, 112/474 deaths (23.6%) vs. control, 244/781 deaths (31.2%); OR 1.42 (95% CI, 1.04-1.95), p = 0.03, I 2 = 15%).

CONCLUSIONS

CHT for the treatment of posttraumatic ICH was associated with improved adjusted 90-day survival. This result was strengthened by a review of the literature.

Sodium variability is associated with increased mortality in severe burn injury

BACKGROUND

Dysnatremias are associated with increased mortality in critically ill patients. Hypernatremia in burn patients is also associated with poor survival. Based on these findings, we hypothesized that high plasma sodium variability is a marker for increased mortality in severely burn-injured patients.

METHODS

We performed a retrospective review of adult burn patients with a burn injury of 15% total body surface area (TBSA) or greater from 2010 to 2014. All patients included in the study had at least three serum sodium levels checked during admission. We used multivariate logistic regression analysis to determine if hypernatremia, hyponatremia, or sodium variability independently increased the odds ratio (OR) for death.

RESULTS

Two hundred twelve patients met entry criteria. Mean age and %TBSA for the study was 45 ± 18 years and 32 ± 19%. Twenty-nine patients died for a mortality rate of 14%. Serum sodium was measured 10,310 times overall. The median number of serum sodium measurements per patient was 22. Non-survivors were older (59 ± 19 vs. 42 ± 16 years) and suffered from a more severe burn injury (50 ± 25% vs. 29 ± 16%TBSA). While mean sodium was significantly higher for non-survivors (138 ± 3 milliequivalents/liter (meq/l)) than for survivors (135 ± 2 meq/l), mean sodium levels remained within the laboratory reference range (135 to 145 meq/l) for both groups. Non-survivors had a significantly higher median number of hypernatremic (> 145 meq/l) measurements (2 vs. 0). Coefficient of variation (CV) was significantly higher in non-survivors (2.85 ± 1.1) than survivors (2.0 ± 0.7). Adjusting for TBSA, age, ventilator days, and intensive care unit (ICU) stay, a higher CV of sodium measurements was associated with mortality (OR 5.8 (95% confidence interval (CI) 1.5 to 22)). Additionally, large variation in sodium ranges in the first 10 days of admission may be associated with increased mortality (OR 1.35 (95% CI 1.06 to1.7)).

CONCLUSIONS

Increased variability in plasma sodium may be associated with death in severely burned patients.

Serum sodium correction rate and the outcome in severe hyponatremia

STUDY OBJECTIVE

We investigated the serum sodium correction rate on length of hospitalization and survival rate, in severe chronic hyponatremic patients at the Emergency Department (ED).

DESIGN

An observational study using clinical chart review.

SETTING

The ED of the University Hospital of Marcianise, Caserta, Italy with approximately 30,000 patients visits a year.

TYPE OF PARTICIPANTS

We reviewed sixty-seven patients with severe hyponatremia subdivided in 2 subgroups: group A consisting of 35 patients with serum sodium correction rate<0.3mmol/h and group B consisting of 32 patients with serum sodium correction rate between <0.5 and ≥0.3mmol/h.

INTERVENTION

Emergency patients were evaluated for serum sodium correction rate for hyponatremia by clinical chart review.

MEASUREMENTS AND MAIN RESULTS

Severe hyponatremia was defined as a serum sodium level<120mmol/l. Mean serum sodium correction rate of hyponatremia was of 0.17±0.09% in group A and 0.41±0.05% in group B (p<0.001 vs group A). The length of hospital stay was 10.7±3.7days for group A, and it was significantly decreased to 3.8±0.4days for group B (p<0.005 vs group A). In addition we observed that correction rate of hyponatremia in group A was associated with a significantly lower survival rate (25%) in comparison to group B (60%) (p<0.001 vs group A).

CONCLUSION

We observed that serum sodium correction rate ≥0.3 and <0.5mmol/h was associated with a shorter length of hospital stay and a major survival rate.

The Reduction Rate of Serum Sodium and Mortality in Patients Undergoing Continuous Venovenous Hemofiltration for Acute Severe Hypernatremia

BACKGROUND

The excessive correction of acute hypernatremia is not known to be harmful. This study aimed to evaluate whether a reduction rate of serum sodium (RRSeNa) > 1mEq/L/hour in acute severe hypernatremia is an independent risk factor for mortality in critically ill patients undergoing continuous venovenous hemofiltration (CVVH) treatment.

MATERIALS AND METHODS

For this retrospective study, we reviewed records of 75 critically ill patients undergoing CVVH treatment for acute severe hypernatremia between March 2011 and March 2015.

RESULTS

The 28-day mortality rate of all patients was 61.3%. In multivariate Cox regression analyses, a reduction rate of serum sodium (RRSeNa) > 1mEq/L/hour (hazard ratio = 1.89; 95% CI: 1.03-3.47; P = 0.04), Acute Physiology and Chronic Health Evaluation II score and vasopressor dependency (yes or no) had a statistically significantly effect on mortality. Once we excluded patients with an RRSeNa ≤ 0.5mEq/L/hour, only RRSeNa > 1mEq/L/hour (hazard ratio = 2.611; 95% CI: 1.228-5.550; P = 0.013) and vasopressor dependency had a statistically significant influence on mortality in multivariate regression.

CONCLUSIONS

In addition to the Acute Physiology and Chronic Health Evaluation II score and vasopressor dependency, the excessive correction of acute severe hypernatremia was possibly associated with mortality in critically ill patients undergoing CVVH treatment. The optimal reduction rate of acute hypernatremia should be extensively studied in critically ill patients.

The Sodium Paradox: Dysnatremia and Mortality in Patients Implanted With Extracorporeal Mechanical Circulatory Support Devices

INTRODUCTION

Dysnatremia, abnormal serum sodium levels, has long been used as a marker for disease progression in heart failure patients. Classically, hyponatremia is associated with increased fluid volume in heart failure and is often a result of neuroendocrine dysfunction and poor cardiac output. Recent studies have noted that dysnatremia and hypernatremia are predictive of worsened outcomes in critical care and renal disease populations. We investigated the relationship between dysnatremia and postoperative outcomes in patients implanted with extracorporeal mechanical circulatory devices.

METHODS

A total of 97 patients who underwent implantation with the CentriMag mechanical circulatory assist system were included in this retrospective study. Patients were divided into 2 groups based on preoperative serum sodium level cutoff of 135 mEq/L. Outcomes and mortality were compared between groups.

RESULTS

The mean age for the study population was 56.21 ± 15.13 years, and 57 patients (58.8%) were male. The mean time on CentriMag support was 22.7 days. Patients with serum sodium levels ≤135 mEq/L were noted to have significantly worsened indicators of preoperative cardiac function. However, patients with serum sodium levels >135 mEq/L had significantly shorter postoperative survival ( P = .006). When entered into a multivariate Cox proportional hazards model, sodium was an independent predictor for increased risk of mortality (hazard ratio: 1.224; 95% confidence interval: 1.009-1.485; P = .040).

CONCLUSION

Our results indicate that elevated preoperative sodium in patients undergoing implantation of a temporary mechanical circulatory support system is predictive of worsened postoperative survival.

Incidence, severity and prognosis associated with hypernatremia in dogs and cats

Background

Hypernatremia has been associated with substantial morbidity and death in human patients. The incidence and importance of hypernatremia in dogs and cats has not been determined.

Hypothesis/Objectives

To describe the incidence of and prognosis associated with hypernatremia in dogs and cats at a university teaching hospital.

Animals

A total of 16,691 dogs and 4,211 cats with measured blood or serum sodium concentration.

Methods

Retrospective study. Medical records of animals with a blood or serum sodium concentration measured during a 60‐month period were reviewed to determine the severity of hypernatremia and its associated case fatality rate. Cases with moderate (11–15 mmol/L above the reference range) or severe hypernatremia (≥16 mmol/L above the reference range) were further reviewed.

Results

A total of 957 dogs (5.7%) and 338 cats (8.0%) were diagnosed with hypernatremia. Case fatality rates of dogs and cats with hypernatremia was 20.6 and 28.1%, respectively compared to 4.4 and 4.5% with a normal blood or serum sodium concentration (P < .0001). The magnitude of hypernatremia was linearly associated with a higher case fatality rate (P < .0001). Hypernatremia was associated with a higher case fatality rate than hyponatremia. Among the animals with moderate or severe hypernatremia, 50% of dogs and 38.5% of cats presented with community‐acquired hypernatremia, and 50% of dogs and 61.5% of cats developed hospital‐acquired hypernatremia.

Conclusions and clinical importance

Hypernatremia was found infrequently in this population but was associated with increased case fatality rates in dogs and cats. Presence and severity of hypernatremia might be useful as a prognostic indicator.

Long-term changes in dysnatremia incidence in the ICU: a shift from hyponatremia to hypernatremia

Background

Dysnatremia is associated with adverse outcome in critically ill patients. Changes in patients or treatment strategies may have affected the incidence of dysnatremia over time. We investigated long-term changes in the incidence of dysnatremia and analyzed its association with mortality.

Methods

Over a 21-year period (1992–2012), all serum sodium measurements were analyzed retrospectively in two university hospital ICUs, up to day 28 of ICU admission for the presence of dysnatremia. The study period was divided into five periods. All serum sodium measurements were collected from the electronic databases of both ICUs. Serum sodium was measured at the clinical chemistry departments using standard methods. All sodium measurements were categorized in the following categories: <120, 120–124, 125–129, 130–134, 135–139, 140–145, 146–150, 151–155, 156–160, >160 mmol/L. Mortality was determined at 90 days after ICU admission.

Results

In 80,571 ICU patients, 913,272 serum sodium measurements were analyzed. A striking shift in the pattern of ICU-acquired dysnatremias was observed: The incidence of hyponatremia almost halved (47–25 %, p < 0.001), whereas the incidence of hypernatremia nearly doubled (13–24 %, p < 0.001). Most hypernatremias developed after ICU admission, and the incidence of severe hypernatremia (sodium > 155 mmol/L) increased dramatically over the years. On ICU day 10 this incidence was 0.7 % in the 1992–1996 period, compared to 6.3 % in the 2009–2012 period (p < 0.001). More severe dysnatremia was associated with significantly higher mortality throughout the 21-year study period (p < 0.001).

Conclusions

In two large Dutch cohorts, we observed a marked shift in the incidence of dysnatremia from hyponatremia to hypernatremia over two decades. As hypernatremia was mostly ICU acquired, this strongly suggests changes in treatment as underlying causes. This shift may be related to the increased use of sodium-containing infusions, diuretics, and hydrocortisone. As ICU-acquired hypernatremia is largely iatrogenic, it should be—to an important extent—preventable, and its incidence may be considered as an indicator of quality of care. Strategies to prevent hypernatremia deserve more emphasis; therefore, we recommend that further study should be focused on interventions to prevent the occurrence of dysnatremias during ICU stay.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-016-0124-x) contains supplementary material, which is available to authorized users.

Are all fluids bad for the kidney?

PURPOSE OF REVIEW

To describe the harmful effects of intravenous fluids on kidney structure and function and summarize recent comparisons between different fluids and their effect on kidney outcome.

RECENT FINDINGS

Administration of intravenous fluids may contribute to the development and sustention of acute kidney injury. In excess, fluids cause kidney interstitial edema and venous congestion, which prevents renal blood flow and glomerular filtration rate. In contrast to balanced crystalloids, chloride-rich solutions impair renal blood flow via autoregulatory mechanisms. Synthetic colloids, such as hydroxyethyl starches, gelatins, and dextrans are potentially nephrotoxic because they can cause osmotic nephrosis, which, in susceptible patients, might precede permanent kidney damage. Albumin solutions appear well tolerated to use in septic patients, although their renal efficacy over balanced crystalloids is not established. In contrast, administration of albumin solutions to patients with decompensated liver failure effectively prevents and ameliorates hepatorenal syndrome.

SUMMARY

Being nephrotoxic, synthetic colloids should be avoided in patients with reduced renal reserve, such as in critically ill patients and in patients with preexisting renal dysfunction. Suggested adverse effects with chloride-rich solutions need confirmation from ongoing trials. Albumin solutions are well tolerated in patients with sepsis and/or liver failure and improve outcomes in the latter.

Hyponatremia and hypernatremia are associated with increased 30-day mortality in hip fracture patients

Using data from the Danish national registries on 7317 patients, this study shows that abnormal plasma sodium levels, in the form of hyponatremia and hypernatremia, are prevalent and associated with increased 30-day mortality in hip fracture patients.

INTRODUCTION

The aim of this study was to examine the prevalence of hyponatremia and hypernatremia in patients admitted with a fractured hip as well as the association with 30-day in mortality in these patients.

METHODS

A total of 7317 hip fracture patients (aged 60 years or above) with admission plasma sodium measurements were included. Data on comorbidity, medication, and death was retrieved from Danish national registries. The association between plasma sodium and mortality was examined using Cox proportional hazard models.

RESULTS

The prevalence of hyponatremia and hypernatremia on admission was 19.0 and 1.7 %, respectively. Thirty-day mortality was increased for patients with hyponatremia (12.2 %, p = 0.005) and hypernatremia (15.5 %, p = 0.03) compared to normonatremic patients (9.6 %). After adjustment for possible confounding factors, hyponatremia (1.38 [1.16-1.64], p = 0.0003) and hypernatremia (1.71 [1.08-2.70], p = 0.02) were still associated with increased risk of death by 30 days. Looking at the association between changes in plasma sodium during admission and mortality, there was no difference between patients with normalized and persistent hyponatremia (10.4 vs 11.3 %, p = 0.6) while a lower mortality was found for normalized hypernatremia compared to persistent hypernatremia (12.4 vs 33.3 %, p = 0.03).

CONCLUSIONS

This study shows that abnormal plasma sodium levels are prevalent in patients admitted with a fractured hip and that both hyponatremia and hypernatremia are associated with increased risk of death within 30 days of admission.

The severity of initial acute kidney injury at admission of geriatric patients significantly correlates with subsequent in-hospital complications

Acute kidney injury (AKI) is associated with higher hospital mortality. However, the relationship between geriatric AKI and in-hospital complications is unclear. We prospectively enrolled elderly patients (≥65 years) from general medical wards of National Taiwan University Hospital, part of whom presented AKI at admission. We recorded subsequent in-hospital complications, including catastrophic events, incident gastrointestinal bleeding, hospital-associated infections, and new-onset electrolyte imbalances. Regression analyses were utilized to assess the associations between in-hospital complications and the initial AKI severity. A total of 163 elderly were recruited, with 39% presenting AKI (stage 1: 52%, stage 2: 23%, stage 3: 25%). The incidence of any in-hospital complication was significantly higher in the AKI group than in the non-AKI group (91% vs. 68%, p < 0.01). Multiple regression analyses indicated that elderly patients presenting with AKI had significantly higher risk of developing any complication (Odds ratio [OR] = 3.51, p = 0.01) and new-onset electrolyte imbalance (OR = 7.1, p < 0.01), and a trend toward more hospital-associated infections (OR = 1.99, p = 0.08). The risk of developing complications increased with higher AKI stage. In summary, our results indicate that initial AKI at admission in geriatric patients significantly increased the risk of in-hospital complications.

Incidence, Severity and Prognosis Associated with Hyponatremia in Dogs and Cats

Background

Hyponatremia is a common electrolyte abnormality in human patients and is associated with substantial morbidity and death. The incidence and importance of hyponatremia in dogs and cats has not been determined.

Hypothesis/Objectives

To describe the incidence of and prognosis associated with hyponatremia in dogs and cats at a university teaching hospital.

Animals

Of 16,691 dogs and 4,211 cats with measured blood or serum sodium concentration.

Methods

Retrospective study. Medical records of animals with a blood or serum sodium concentration measured during a 60‐month period were reviewed to determine the severity of hyponatremia and its associated fatality rate. Cases with moderate (11–15 mmol/L below the reference range) or severe hyponatremia (≥16 mmol/L below the reference range) were further reviewed.

Results

Of 4,254 dogs (25.5%) and 2,081 cats (49.4%) were diagnosed with hyponatremia. Case fatality rates of dogs and cats with hyponatremia were 13.7% and 11.9%, respectively, compared to 4.4% and 4.5% with a normal blood or serum sodium concentration (P < 0.0001). The magnitude of hyponatremia was linearly associated with a higher case fatality rate (P < 0.0001). Hyponatremia was associated with a lower case fatality rate than hypernatremia in the same population. Among the animals with moderate or severe hyponatremia, 92.1% of dogs and 90.6% of cats presented with community‐acquired hyponatremia, and 7.9% of dogs and 9.4% of cats developed hospital‐acquired hyponatremia.

Conclusions and clinical importance

Hyponatremia was found commonly in this population and was associated with increased case fatality rate. Presence and severity of hyponatremia might be useful as a prognostic indicator.

Fluid and electrolyte overload in critically ill patients: An overview

Fluids are considered the cornerstone of therapy for many shock states, particularly states that are associated with relative or absolute hypovolemia. Fluids are also commonly used for many other purposes, such as renal protection from endogenous and exogenous substances, for the safe dilution of medications and as “maintenance” fluids. However, a large amount of evidence from the last decade has shown that fluids can have deleterious effects on several organ functions, both from excessive amounts of fluids and from their non-physiological electrolyte composition. Additionally, fluid prescription is more common in patients with systemic inflammatory response syndrome whose kidneys may have impaired mechanisms of electrolyte and free water excretion. These processes have been studied as separate entities (hypernatremia, hyperchloremic acidosis and progressive fluid accumulation) leading to worse outcomes in many clinical scenarios, including but not limited to acute kidney injury, worsening respiratory function, higher mortality and higher hospital and intensive care unit length-of-stays. In this review, we synthesize this evidence and describe this phenomenon as fluid and electrolyte overload with potentially deleterious effects. Finally, we propose a strategy to safely use fluids and thereafter wean patients from fluids, along with other caveats to be considered when dealing with fluids in the intensive care unit.

Hyponatremia improvement is associated with a reduced risk of mortality: evidence from a meta-analysis

BACKGROUND

Hyponatremia is the most common electrolyte disorder and it is associated with increased morbidity and mortality. However, there is no clear demonstration that the improvement of serum sodium concentration ([Na(+)]) counteracts the increased risk of mortality associated with hyponatremia. Thus, we performed a meta-analysis that included the published studies that addressed the effect of hyponatremia improvement on mortality.

METHODS AND FINDINGS

A Medline, Embase and Cochrane search was performed to retrieve all English-language studies of human subjects published up to June 30th 2014, using the following words: "hyponatremia", "hyponatraemia", "mortality", "morbidity" and "sodium". Fifteen studies satisfied inclusion criteria encompassing a total of 13,816 patients. The identification of relevant abstracts, the selection of studies and the subsequent data extraction were performed independently by two of the authors, and conflicts resolved by a third investigator. Across all fifteen studies, any improvement of hyponatremia was associated with a reduced risk of overall mortality (OR=0.57[0.40-0.81]). The association was even stronger when only those studies (n=8) reporting a threshold for serum [Na(+)] improvement to >130 mmol/L were considered (OR=0.51[0.31-0.86]). The reduced mortality rate persisted at follow-up (OR=0.55[0.36-0.84] at 12 months). Meta-regression analyses showed that the reduced mortality associated with hyponatremia improvement was more evident in older subjects and in those with lower serum [Na(+)] at enrollment.

CONCLUSIONS

This meta-analysis documents for the first time that improvement in serum [Na(+)] in hyponatremic patients is associated with a reduction of overall mortality.