Serum osmolality and hyperosmolar states

Evaluation of measurement uncertainty in direct and estimated serum osmolality according to ISO/TS 20914: implications for clinical diagnostics

This study examines the measurement uncertainties (MU) associated with osmolality (OSM), a crucial parameter in clinical diagnostics and treatment. The research compares the uncertainties of directly measured osmolality (dOSM) with those of estimated osmolality (eOSM), which is calculated based on sodium, glucose, and urea levels. Using ISO/TS 20914 guidelines, the study evaluates the MUs of eOSM across different analyzer models and internal quality control (IQC) lots and compares these values with dOSM. In the materials and methods section, sodium, glucose, and urea analyses were performed using two different analyzers (Atellica CH and Advia Chemistry XPT, Siemens Healthineers). OSM was measured using the freezing point depression method (Osmomat Auto, Gonotec) and data were collected to calculate eOSM. MU (k = 2, 95% confidence) calculations were conducted according to the ISO/TS 20914 standard for each system. The results show that the expanded standard MU (k = 2, 95% confidence) for dOSM is low at 5.56 mOSM/L, while the MU for eOSM is 8.54 mOSM/L for the Atellica CH system and 11.13 mOSM/L for the Advia Chemistry XPT system. These findings indicate that eOSM has higher uncertainty, suggesting it should be used with caution in clinical practice.

The U-shaped relationship between serum osmolality and in-hospital mortality in patients with traumatic brain injury: a retrospective study based on the MIMIC-IV database

BACKGROUND

Disturbances in serum osmolality are associated with poor prognosis in many diseases and are more likely to occur in patients with traumatic brain injury (TBI). However, studies correlating serum osmolality and patient prognosis are lacking. Therefore, this study investigated the correlation between serum osmolality and in-hospital all-cause mortality in patients with TBI based on a large sample of TBI patients from the Medical Information Mart for Intensive Care-IV (MIMIV-IV) database.

METHODS

Patients were categorized into 4 groups based on serum osmolality levels and the association between serum osmolality and in-hospital all-cause mortality was assessed by constructing univariate and multivariate logistic regression analyses. Restricted cubic spline (RCS) curves were plotted to further assess nonlinear associations between study variables and outcomes. Kaplan-Meier analysis was used to assess the survival of patients in each group, and differences between groups were assessed by the log-rank test. Sensitivity analysis was used to assess whether this association was established in different populations.

RESULTS

This study covered 1587 patients. The Q3 group had the lowest in-hospital mortality (7.6%). After fully adjusting for confounders, either lower or higher serum osmolality levels were associated with in-hospital all-cause mortality (Q1 vs. Q3: OR, 2.244 [1.333-3.857] p = 0.003; Q4 vs. Q3: OR, 2.160 [1.295-3.681] p = 0.004). The RCS curves showed a U-shaped correlation, with the inflection point located at a serum osmolality of 295.4 mmol/L level.

CONCLUSIONS

There was a U-shaped relationship between serum osmolality and in-hospital all-cause mortality in TBI patients. Patients had the lowest in-hospital mortality when serum osmolarity was maintained at 295.4 mmol/L.

Analysis of the correlation between the group-based trajectory modeling of serum osmolality and prognosis in patients with sepsis-associated encephalopathy at 72 h after admission

BACKGROUND

This study aimed to identify distinct trajectories of serum osmolality within the first 72 h for patients with sepsis-associated encephalopathy (SAE) in the MIMIC-IV and eICU-CRD databases and assess their impact on mortality and adverse clinical outcomes.

METHODS

In this retrospective cohort study, patients with SAE from the MIMIC-IV database were included. Group-based trajectory modeling (GBTM) was used to categorize distinct patterns of serum osmolality changes over 72 h in ICU patients. Differences in survival across the trajectory groups were compared using Kaplan-Meier (K-M) survival curves.

RESULTS

A total of 11,376 patients with SAE were included in the analysis, with a median age of 65.6 ± 16.5 years. The in-hospital mortality rate at 30 days was 12.8%. Based on model-defined criteria, three distinct osmolality trajectory groups were identified: Group 1 (59.6%), Group 2 (36.4%), and Group 3 (4.0%). Kaplan-Meier survival analysis indicated that patients with relatively lower serum osmolality within the normal range (Group 1) had a lower 30-day mortality rate compared to those in the other groups (Group 2 and 3). Subgroup analysis demonstrated significant interactions (P < 0.05) between osmolality trajectories and covariates such as the Sequential Organ Failure Assessment (SOFA), vasopressor use and renal replacement therapy (RRT).

CONCLUSION

Identifying distinct serum osmolality trajectories may help recognize SAE patient subgroups with varying risks of adverse outcomes, providing clinically meaningful stratification.

Impact of adolescents' binge drinking on blood chemistry

Adolescent binge drinking is increasingly common. This study investigates the anomalies in glucose, sodium, calcium, potassium, and acid-base homeostasis induced by binge drinking in adolescents. The records of teenagers who sought medical attention for binge drinking (ethanol level ≥ 0.80 g/L) at the Pediatric Emergency Department, Ca' Granda Ospedale Maggiore Policlinico, Milan (Italy), spanning the years 2013 to 2023 were retrospectively analyzed. For this analysis, cases were selected if documented blood chemistry encompassed sodium, potassium, total calcium, glucose, acid-base balance, and lactic acid (only for those with metabolic acidosis). Included were 173 adolescents (female-to-male ratio 0.94), 13.2 to 18.4, median 16.4 years of age. Hypoglycemia (≤ 3.3 mmol/L; N = 1, 0.6%), hyponatremia (≤ 134 mmol/L; N = 7, 4.0%), hypernatremia (≥ 146 mmol/L; N = 3, 1.7%), hypocalcemia (≤ 2.19 mmol/L; N = 0) hypercalcemia (≥ 2.61 mmol/L; N = 0), and hyperkalemia (≥ 5.1 mmol/L; N = 0) were infrequent. Acute respiratory acidosis (pCO2 ≥ 46 mm Hg; pH < 7.40; N = 101, 58%) was the most common acid-base imbalance, followed by respiratory alkalosis (pCO2 ≤ 34 mm Hg; pH > 7.40; N = 10, 5.6%), and metabolic acidosis (HCO3- ≤ 19 mmol/L, pH < 7.40; N = 9, 5.2%). The lactic acid level was increased (≥ 2.1 mmol/L) in all cases with metabolic acidosis. Metabolic alkalosis (HCO3- ≥ 28 mmol/L, pH > 7.40) never occurred. Hypokalemia (≤ 3.4 mmol/L; N = 56, 32%) was prevalent, particularly in adolescents with normal acid-base equilibrium or metabolic acidosis, rather than respiratory acidosis or alkalosis.Conclusion: Adolescents who engage in binge drinking often experience a disrupted acid-base balance and hypokalemia, while glucose, sodium and calcium levels are rarely affected. What is known? • Binge drinking is becoming increasingly common among adolescents. • Conflicting data regarding the type and prevalence of biochemical disorders induced by binge drinking are available in this age group. What is new? • Acute respiratory acidosis is prevalent in adolescents with binge drinking, whereas respiratory alkalosis, metabolic acidosis, and hypoglycemia are uncommon. • Hypokalemia develops frequently.

Beneficial Effect of Pretreatment Hyperosmolality on Outcome in Severe Traumatic Brain Injury: Evidence from a South Korean Multicenter Registry and Propensity Score Matching Analysis

BACKGROUND

Hyperosmolar therapy has long been a cornerstone in managing increased intracranial pressure and improving outcomes in severe traumatic brain injury (TBI). This therapy hinges on elevating serum osmolality, creating an osmotic gradient that draws excess water from the brain's cellular and interstitial compartments and effectively reducing cerebral edema. Given this information, we hypothesized that the serum hyperosmolality prior to any treatment could significantly impact the clinical outcomes of patients with severe TBI, potentially mitigating secondary cerebral edema after trauma.

METHODS

Data were extracted from the Korean Multi-center Traumatic Brain Injury data bank, encompassing 4628 patients with TBI admitted between January 2016 and December 2018. Of these, 507 patients diagnosed with severe TBI (Glasgow Coma Scale score < 9) were selected for comprehensive analysis across four data domains: clinical, laboratory, initial computed tomography scan, and treatment. Serum osmolality was assessed prior to treatment, and the hyperosmolar group was defined by a pretreatment serum osmolality exceeding 320 mOsm/L, whereas favorable outcomes were characterized by a modified Rankin Scale score of ≤ 3 at 6 months after trauma. Multivariate regression with receiver operating characteristic curve analysis and propensity score matching were used to dissect the data set.

RESULTS

Multivariate analysis showed serum osmolality is significantly associated with clinical outcome in patients with severe TBI (p < 0.001). The optimal cutoff value for predicting favorable outcome was 331 mOsm/L, with a sensitivity of 38.9% and a specificity of 87.7%. Notably, the propensity score matching analysis comparing patients with pretreatment serum hyperosmolality with those without indicated a markedly improved functional outcome in the former group (32.5% vs 18.8%, p = 0.025).

CONCLUSIONS

The present study has uncovered a significant correlation between the pretreatment serum osmolality and the clinical outcomes of patients with severe TBI. These findings offer a novel perspective, indicating that a serum hyperosmolality prior to any treatment might potentially have a neuroprotective effect in patients with severe TBI.

Hydration Considerations to Improve the Physical Performance and Health of Firefighters

Background/Objectives: Firefighters are exposed to a high level of stress as they often perform physically challenging work in hazardous environments while responsible for rescuing and keeping those around them safe. To add to this stress, they are also required to work in heavy, unbreathable personal protective equipment which promotes dehydration. These occupational demands paired with dehydration may lead to increased core temperatures, cardiac strain, and overall risk for sudden cardiac events. Thus, it is important to include hydration assessments and determine fluid needs when firefighters are on shift to ensure their personal safety as well as the safety of those around them by optimizing physical performance by maintaining adequate hydration. Therefore, the purpose of this review is to identify markers of hydration, classifications of hydration status, current hydration recommendations, and hydration interventions that may contribute to the overall clarity of hydration protocols that may optimize performance and health of firefighters. In addition, the impact of common medications, exercise training, and health conditions on hydration status related to firefighters will be discussed. Methods: A comprehensive literature search was conducted to discuss the purpose statements. Results: Hydration recommendations for firefighters include (1) assessing hydration status with multiple measurements including body mass, urine specific gravity and thirst sensation, and (2) following general hydration recommendations on rest days and exercise hydration protocols during firefighting activities which may be altered according to hydration status measurements. Conclusion: Randomized controlled trials in firefighters are needed to determine the impact of maintaining adequate hydration on health markers.

The U-shaped association between serum osmolality and 28-day mortality in patients with sepsis: a retrospective cohort study

BACKGROUND

Sepsis is a recognized global health challenge that places a considerable disease burden on countries. Although there has been some progress in the study of sepsis, the mortality rate of sepsis remains high. The relationship between serum osmolality and the prognosis of patients with sepsis is unclear.

METHOD

Patients with sepsis who met the criteria in the Medical Information Mart for Intensive Care IV database were included in the study. Hazard ratios (HRs) and 95% confidence intervals (CIs) were determined using multivariable Cox regression. The relationship between serum osmolality and the 28-day mortality risk in patients with sepsis was investigated using curve fitting, and inflection points were calculated.

RESULTS

A total of 13,219 patients with sepsis were enrolled in the study; the mean age was 65.1 years, 56.9 % were male, and the 28-day mortality rate was 18.8 %. After adjusting for covariates, the risk of 28-day mortality was elevated by 99% (HR 1.99, 95%CI 1.74-2.28) in the highest quintile of serum osmolality (Q5 >303.21) and by 59% (HR 1.59, 95%CI 1.39-1.83) in the lowest quintile (Q1 ≤285.80), as compared to the reference quintile (Q3 291.38-296.29). The results of the curve fitting showed a U-shaped relationship between serum osmolality and the risk of 28-day mortality, with an inflection point of 286.9 mmol/L.

CONCLUSION

There is a U-shaped relationship between serum osmolality and the 28-day mortality risk in patients with sepsis. Higher or lower serum osmolality is associated with an increased risk of mortality in patients with sepsis. Patients with sepsis have a lower risk of mortality when their osmolality is 285.80-296.29 mmol/L.

Association between serum osmolality and deteriorating renal function in patients with acute myocardial infarction: analysis of the MIMIC- IV database

BACKGROUND

To investigate the association between serum osmolality and deteriorating renal function in patients with acute myocardial infarction (AMI).

METHODS

Three thousand eight hundred eighty-five AMI patients from the Medical Information Mart for Intensive Care IV were enrolled for this study. The primary outcome was deteriorating renal function. Secondary outcomes included the new-onset of acute kidney injury (AKI) and progress of AKI. < 293.2725 mmol/L was defined as low serum osmolality, and ≥ 293.2725 mmol/L as high serum osmolality based on upper quartile. Univariate and multivariate logistic regression models were used to explore the associations between serum osmolality and the development of deteriorating renal function, the new-onset of AKI and progress of AKI among AMI patients. Subgroup analysis was also conducted.

RESULTS

One thousand three hundred ninety-three AMI patients developed deteriorating renal function. After adjusting all confounding factors, high serum osmolality was associated with increased risk of deteriorating renal function [odds ratio (OR) = 1.47, 95% confidence interval (CI): 1.22-1.78], new-onset of AKI (OR = 1.31, 95% CI: 1.01-1.69), and progress of AKI risk (OR = 1.26, 95% CI: 1.01-1.59) among AMI patients. In addition, when the stratified analysis was performed for age, AMI type, cardiogenic shock, and estimated glomerular filtration rate (eGFR), high serum osmolality was risk factor for the risk of deteriorating renal function among patients aged 65 years or older, without cardiogenic shock, and with an eGFR ≥ 60 mL/min/1.73m2.

CONCLUSION

Higher serum osmolality increased the risk of deteriorating renal function among AMI patients.

Naoxueshu Oral Liquid Accelerates Post-Craniotomy Hematoma Absorption in Patients: An Open-Label, Multicenter, and Randomized Controlled Trial

OBJECTIVE

To investigate whether Naoxueshu Oral Liquid (NXS) could promote hematoma absorption in post-craniotomy hematoma (PCH) patients.

METHODS

This is an open-label, multicenter, and randomized controlled trial conducted at 9 hospitals in China. Patients aged 18-80 years with post-craniotomy supratentorial hematoma volume ranging from 10 to 30 mL or post-craniotomy infratentorial hematoma volume less than 10 mL, or intraventricular hemorrhage following cranial surgery were enrolled. They were randomly assigned at a 1:1 ratio to the NXS (10 mL thrice daily for 15 days) or control groups using a randomization code table. Standard medical care was administered in both groups. The primary outcome was the percentage reduction in hematoma volume from day 1 to day 15. The secondary outcomes included the percentage reduction in hematoma volume from day 1 to day 7, the absolute reduction in hematoma volume from day 1 to day 7 and 15, and the change in neurological function from day 1 to day 7 and 15. The safety was closely monitored throughout the study. Moreover, subgroup analysis was performed based on age, gender, history of diabetes, and etiology of intracerebral hemorrhage (ICH).

RESULTS

A total of 120 patients were enrolled and randomly assigned between March 30, 2018 and April 15, 2020. One patient was lost to follow-up in the control group. Finally, there were 119 patients (60 in the NXS group and 59 in the control group) included in the analysis. In the full analysis set (FAS) analysis, the NXS group had a greater percentage reduction in hematoma volume from day 1 to day 15 than the control group [median (Q1, Q3): 85% (71%, 97%) vs. 76% (53%, 93%), P<0.05]. The secondary outcomes showed no statistical significance between two groups, either in FAS or per-protocol set (P>0.05). Furthermore, no adverse events were reported during the study. In the FAS analysis, the NXS group exhibited a higher percentage reduction in hematoma volume on day 15 in the following subgroups: male patients, patients younger than 65 years, patients without diabetes, or those with initial cranial surgery due to ICH (all P<0.05).

CONCLUSIONS

The administration of NXS demonstrated the potential to promote the percentage reduction in hematoma volume from day 1 to day 15. This intervention was found to be safe and feasible. The response to NXS may be influenced by patient characteristics. (Registration No. ChiCTR1800017981).

Association between serum osmolality and 28-day all-cause mortality in patients with heart failure and reduced ejection fraction: a retrospective cohort study from the MIMIC-IV database

Background

Previous studies have not thoroughly explored the impact of serum osmolality levels on early mortality in heart failure and reduced ejection fraction (HFrEF) patients. The purpose of this study was to investigate the relationship between serum osmolality levels and early all-cause mortality in patients with HFrEF.

Methods

The open access MIMIC-IV database was the source of data for our study. We collected demographic data, vital signs, laboratory parameters, and comorbidities of the included patients and divided them into 3 groups based on their initial serum osmolality on admission, with the primary outcome being all-cause mortality within 28 days of admission. Smoothing Spline Fitting Curve, the Kaplan-Meier survival curve, and Threshold effect analysis were used to assess the relationship between serum osmolality and early mortality in HFrEF patients.

Results

A total of 6228 patients (55.31% male) were included. All-cause mortality within 28 days on admission was 18.88% in all patients. After adjusting for confounders, higher serum osmolality levels were independently associated with an increased risk of 28-days all-cause mortality compared with the reference group (Reference group Q2: 290-309 mmol/L, Q4: HR, 1.82 [95% CI 1.19-2.78] P<0.05, Q5: HR, 1.99 [95% CI 1.02-3.91] P<0.05). Smooth spline fitting revealed a U-shaped association between serum osmolality and 28-days all-cause mortality. Further threshold effect analysis results suggested that each unit increase in serum osmolality level was associated with a 2% increase in 28-days all-cause mortality when serum osmolality levels were ≥ 298.8 mmol/L (HR, 1.019 [95% CI 1.012-1.025] P<0.05).

Conclusion

A U-shaped correlation between initial serum osmolality and 28-days all-cause mortality in HFrEF patients was identified, revealing higher osmolality levels significantly increase mortality risk. These results underscore serum osmolality's critical role in early mortality among HFrEF patients, highlighting the need for further, larger-scale studies for validation.

High-viscosity driven modulation of biomechanical properties of human mesenchymal stem cells promotes osteogenic lineage

Biomechanical cues could effectively govern cell gene expression to direct the differentiation of specific stem cell lineage. Recently, the medium viscosity has emerged as a significant mechanical stimulator that regulates the cellular mechanical properties and various physiological functions. However, whether the medium viscosity can regulate the mechanical properties of human mesenchymal stem cells (hMSCs) to effectively trigger osteogenic differentiation remains uncertain. The mechanism by which cells sense and respond to changes in medium viscosity, and regulate cell mechanical properties to promote osteogenic lineage, remains elusive. In this study, we demonstrated that hMSCs, cultured in a high-viscosity medium, exhibited larger cell spreading area and higher intracellular tension, correlated with elevated formation of actin stress fibers and focal adhesion maturation. Furthermore, these changes observed in hMSCs were associated with activation of TRPV4 (transient receptor potential vanilloid sub-type 4) channels on the cell membrane. This feedback loop among TRPV4 activation, cell spreading and intracellular tension results in calcium influx, which subsequently promotes the nuclear localization of NFATc1 (nuclear factor of activated T cells 1). Concomitantly, the elevated intracellular tension induced nuclear deformation and promoted the nuclear localization of YAP (YES-associated protein). The concurrent activation of NFATc1 and YAP significantly enhanced alkaline phosphatase (ALP) for pre-osteogenic activity. Taken together, these findings provide a more comprehensive view of how viscosity-induced alterations in biomechanical properties of MSCs impact the expression of osteogenesis-related genes, and ultimately promote osteogenic lineage.

Eu- or hypoglycemic ketosis and ketoacidosis in children: a review

The last decade has been characterized by exciting findings on eu- or hypoglycemic ketosis and ketoacidosis. This review emphasizes the following five key points: 1. Since the traditional nitroprusside-glycine dipstick test for urinary ketones is often falsely negative, the blood determination of β-hydroxybutyrate, the predominant ketone body, is currently advised for a comprehensive assessment of ketone body status; 2. Fasting and infections predispose to relevant ketosis and ketoacidosis especially in newborns, infants, children 7 years or less of age, and pregnant, parturient, or lactating women; 3. Several forms of carbohydrate restriction (typically less than 20% of the daily caloric intake) are employed to induce ketosis. These ketogenic diets have achieved great interest as antiepileptic treatment, in the management of excessive body weight, diabetes mellitus, and in sport training; 4. Intermittent fasting is more and more popular because it might benefit against cardiovascular diseases, cancers, neurologic disorders, and aging; 5. Gliflozins, a new group of oral antidiabetics inhibiting the renal sodium-glucose transporter 2, are an emerging cause of eu- or hypoglycemic ketosis and ketoacidosis. In conclusion, the role of ketone bodies is increasingly recognized in several clinical conditions. In the context of acid-base balance evaluation, it is advisable to routinely integrate both the assessment of lactic acid and β-hydroxybutyrate.

The association between malnutrition and dehydration in older adults admitted to a geriatric unit: An observational study

BACKGROUND AND AIM

There is an overlap between the risk factors causing low intake of water and low intake of nutrients, respectively. This study aims to explore the agreement between the assessment of malnutrition and the outcome of low-intake dehydration in a population of older hospitalized patients.

METHODS

Patients ≥65 years old and hospitalized at the geriatric hospital ward were screened for eligibility within 96 h of admission. Dehydration was assessed with the calculated serum osmolarity ≥295 mmol/L (1.86 × (Na+ + K+) + 1.15 × glucose + urea + 14), and (risk of) malnutrition was assessed with NRS-2002 ≥ 3 points, MNA-SF ≤ 7 points, MNA-LF < 17, MUST ≥ 2 points, and GLIM after screening with NRS-2002 and MNA-LF. Follow-up data regarding exercise rehabilitation, readmissions, and mortality was collected 30 days after discharge. Statistics used were the Chi-squared test, Fishers-exact test, and Wilcoxon signed rank test.

RESULTS

A total of 114 patients (57% females) were included. Median age 85.5 (IQR 80; 89.25) years. A total of 49 (43%) were dehydrated. Fewer females were dehydrated (F: 42.9% vs. M: 67.7%, p = 0.013). The patients with osmolarity ≥295 mmol/L had a higher median weight (68.3 (IQR 58.5; 78.4) vs. 62 (IQR 51.8; 72.1), p = 0.021) and mid-up-arm circumference (27 (IQR 26; 30) vs. 25.5 (IQR 22.9; 28.3), p = 0.004). No significant difference was found in the prevalence of malnutrition between those with or without dehydration (NRS-2002; 70% vs. 81%, p = 0.174; MNA-SF: 23.1 vs. 23.2%, p = 1.0; MNA-LF: 37.1 vs. 30.2%, p = 0.644; MUST: 24.5 vs. 33.8%, p = 0.308; GLIM after screening with NRS-2002: 84.4 vs. 74.5%, p = 0.405, GLIM after screening with MNA-LF: 74.1 vs. 75.6%, p = 0.438). Kappa values varied around 0 and reflected low agreement. There were no differences in the follow-up data, between those who were normohydrated and those who were dehydrated.

CONCLUSION

We found low agreement between the assessment of malnutrition and low-intake dehydration in a population of older hospitalized patients. All geriatric patients should therefore be assessed for both conditions.