Effective Osmolality Research Articles

P-219 Does a dry or humid incubation environment affect continuous and undisturbed culture media protocols?

Abstract Study question Can continuous embryo culture medium maintain a safe and effective osmolality in dry and humidified incubators under both light viscosity and heavy viscosity oil overlay? Summary answer Undisturbed embryo culture is possible in 25uL and 100uL media volumes with both light and heavy oil and in both dry and humidified environments. What is known already Ideal osmolality for pre-implantation embryos is 255-295 mOsm/kg. Much debate surrounds continuous embryo culture, without refreshing of the medium, providing a suitable concentration of osmoles during embryo culture in both humidified and dry incubators. Meanwhile, ideal pH or measure of free hydrogen ions available in the embryo culture medium is 7.20-7.50. Contemporary knowledge that undisturbed embryos are able to regulate their own needs during culture has replaced belief that embryos require specific and varying environmental pH induced at different developmental stages. Thus, environmental pH needs to be maintained and stable in order to optimize health and outcomes of resulting blastocysts. Study design, size, duration Osmolality, pH, and mass were measured in humidified and dry incubators over 8 days of continuous embryo culture conditions. Four dishes each of 25uL and 100uL drops of embryo culture medium (CSCM-NXC) were analyzed per incubator type (Non-humidified – Miri, Humidified – Astec). Additionally, each micro-volume was analyzed under both Light Oil for Embryo Culture and Heavy Oil for Embryo Culture (Irvine Scientific). In total, 2352 data points for osmolality, pH, and mass were examined. Participants/materials, setting, methods A private IVF laboratory conducted the testing with no patient samples introduced to the embryo culture media. To mitigate early evaporative loss, dish preparation was strictly time and temperature controlled. Osmolality was measured in triplicate on days 0-7 using Advanced Micro-Osmometer Model 330 (Advanced Instruments). Mass measures were taken in triplicate on days 0-7 using the Torbal AGZN120 Analytical Balance. pH was measured in triplicate using the i-STAT 300 (Abbott) on days 0,3,5,7. Main results and the role of chance The pH in 25uL and 100uL drops under light oil and heavy oil remained well within suitable ranges and stable when compared day to day, from day 0 (M = 7.276, σ = 0.011) through day 7 (M = 7.303, σ = 0.011). The average aggregate pH overall was 7.290 (σ = 0.012). Aggregate osmolality, measured as milliosmoles per kilogram (mOSM/kg), over the course of incubation in all conditions also remained well within acceptable safety range (M = 277mOsm/kg, σ = 5). Dry incubator incubation exhibits a 7% increase from day 0 to day 6 (M = 270mOsm/kg, σ = 4 and M = 289mOsm/kg, σ = 5) compared to a 2% increase in humidified incubation (M = 269mOsm/kg, σ = 5 and M = 274mOsm/kg, σ = 5) regardless of oil type or microdrop size, both remaining within accepted limits. Additionally, when monitoring mass in grams (g) in 25uL as a function of evaporative loss, humidified incubation reduces from 12.6346g to 12.5566g (day 0 to day 7). In dry incubation, there is negligible change day 0 to day 7 (12.6543g and 12.6538g). Similarly, in 100uL, the change in humidified incubators is 13.37222g to 13.25025g (day 0 to day 7) and dry incubation reduces from 13.3236g to 13.2963g. The changes in mass of prepared culture dishes maintains consistency with the study findings for osmolality. Limitations, reasons for caution As CSCM-NXC is for use through day 6 of embryo culture, the extended simulated embryo culture length is for data collection purposes only. There is no developmental data to include in this study. Additional studies must be conducted in order to explore any differences when embryos are present in culture. Wider implications of the findings The ability to culture embryos continuously in dry incubator environments with micro-volumes of culture medium is widely debated. These many data point study has shown that safe and efficacious embryo culture can be undertaken undisturbed, therefore relaxing some of the burdensome and labor-intensive processes in laboratories employing this equipment. Trial registration number not applicable

Spontaneous hydropneumothorax with unknown origin and new onset hyperosmolar hyperglycemic state: case report in limited health facility

Introduction: Hydropneumothorax and Hyperosmolar Hyperglycaemic State (HHS) are uncommon disorders with serious mortality. Both conditions need appropriate intervention and monitoring in comprehensive health facilities. Reports on the occurrence of spontaneous hydropneumothorax accompanied by HHS are still limited, due to the rarity of these two disorders.Case Presentation: A 42-year-old woman with abrupt shortness of breath started 1 day ago. No coughing or chest pain. Losing weight in last six months. There was no history of any disease and medication. Physical findings were drowsy consciousness with tachycardia and weak pulse, asymmetrical chest expansion with retraction, vesicular breath sounds diminished in the left lung following hyper resonant in percussion. The extremities were cold and dry. Skin turgor was reduced. Plain CXR revealed air and fluid in left pleural cavity. Laboratory test revealed very high blood glucose with hyperosmolarity.Discussion: Hydropneumothorax is the presence of air in the pleural space accompanied by ipsilateral effusion. The manifestations include shortness of breath, increased work of breathing, and sharp chest pain, or asymptomatic. It is unclear whether this patient's hyperglycaemia is related to the occurrence of spontaneous hydropneumothorax. HHS can be diagnosed by effective serum osmolality with glucose levels plus appropriate medical presentation. The management is based on the correction of dehydration, hyperglycaemia, hyperosmolarity, and precipitating conditions.Conclusion: Both hydropneumothorax and HHS have high mortality rates, particularly when the two conditions coexist. This case met some challenging issues that might increase the mortality.

Predicting readmission due to severe hyperglycemia after a hyperglycemic crisis episode

AimThis study aimed to investigate the readmission pattern and risk factors for patients who experienced a hyperglycemic crisis. MethodsPatients admitted to MacKay Memorial Hospital for diabetic ketoacidosis (DKA) or hyperglycemic hyperosmolar state (HHS) between January 2016 and April 2019 were studied. The timing of the first readmission for hyperglycemia and other causes was recorded. Kaplan–Meier analysis was used to compare patients with hyperglycemia and all-cause readmissions. Cox regression was used to identify independent predictors for hyperglycemia and all-cause readmission post-discharge. ResultsThe study cohort included 410 patients, and 15.3 % and 46.3 % of them had hyperglycemia and all-cause readmissions, respectively. The DKA and HHS group showed a similar incidence for hyperglycemia, with the latter group showing a higher incidence of all-cause readmissions. The significant predictors of hyperglycemia readmissions included young age, smoking, hypoglycemia, higher effective osmolality, and hyperthyroidism in the DKA group and higher glycated hemoglobin level in the HHS group. ConclusionsPatients who experienced DKA and HHS had similar hyperglycemia readmission rates; however, predictors in the DKA group were not applicable to the HHS group. Designing different strategies for different types of hyperglycemic crisis is necessary for preventing readmission.

Copeptin Concentrations in Plasma of Healthy Neonates in Relation to Water-Electrolyte Homeostasis in the Early Adaptation Period.

Copeptin (CTproAVP) is a stable by-product of arginine–vasopressin synthesis and reflects its secretion by the pituitary gland, considered as a potential new marker of dehydration. The objective of the study was to investigate CTproAVP measured after the first 48 h of postnatal life in relation to serum effective osmolality, urine osmolality, and vessels filling according to the following variables: delivery mode, postnatal weight loss, fluids administered intravenously to the mother, and fluids given orally to the neonate. A prospective observational study was conducted with 200 healthy term infants (53% male) enrolled. Serum CTproAVP concentrations were measured using the ELISA kit; haematocrit, urine osmolality, serum effective osmolality were assessed after 48 h of life. Sonographic measurements of inferior vena cava (IVC) and aorta (Ao) were performed and IVC/Ao ratios were calculated. No correlations were found between CTproAVP concentrations and both serum effective osmolality and urine osmolality. There was also no association between CTproAVP concentrations and vessel filling represented by IVC/Ao index at 48 h of life.

Hyperosmolar Hyperglycemic State (HHS)

Hyperosmolar hyperglycemic syndrome (HHS) is a clinical condition arising from complications of diabetes mellitus. This clinical condition was previously called a non-ketotic hyperglycemic coma; non-ketotic hyperosmolar hyperglycemic syndrome, and non-ketotic hyperosmolar coma (KHONK). Current HHS diagnostic criteria include plasma glucose levels >600 mg/dL and an increase in effective plasma osmolality >320 mOsm/kg in the absence of ketoacidosis. Hyperosmolar hyperglycemic syndrome (HHS) usually occurs with lower insulinopenia levels compared to diabetic ketoacidosis (DKA), but its pathophysiology is considered the same. The mortality rate in Hyperosmolar hyperglycemic syndrome (HHS) can be up to 20% which is about 10 times higher than the death seen in diabetic ketoacidosis. Clinical outcomes and prognosis in HHS are determined by several factors: age, degree of dehydration, and the absence or absence of other accompanying diseases.

Perturbed body fluid distribution and osmoregulation in response to high salt intake in patients with hereditary multiple exostoses

SummaryBackgroundHereditary Multiple Exostoses (HME) is a rare autosomal disorder characterized by the presence of multiple exostoses (osteochondromas) caused by a heterozygous loss of function mutation in EXT1 or EXT2; genes involved in heparan sulfate (HS) chain elongation. Considering that HS and other glycosaminoglycans play an important role in sodium and water homeostasis, we hypothesized that HME patients have perturbed whole body volume regulation and osmolality in response to high sodium conditions.MethodsWe performed a randomized cross-over study in 7 male HME patients and 12 healthy controls, matched for age, BMI, blood pressure and renal function. All subjects followed both an 8-day low sodium diet (LSD, <50 mmol/d) and high sodium diet (HSD, >200 mmol/d) in randomized order. After each diet, blood and urine samples were collected. Body fluid compartment measurements were performed by using the distribution curve of iohexol and 125I-albumin.ResultsIn HME patients, HSD resulted in significant increase of intracellular fluid volume (ICFV) (1.2 L, p = 0.01). In this group, solute-mediated water clearance was significantly lower after HSD, and no changes in interstitial fluid volume (IFV), plasma sodium, and effective osmolality were observed. In healthy controls, HSD did not influence ICFV, but expanded IFV (1.8 L, p = 0.058) and increased plasma sodium and effective osmolality.ConclusionHME patients show altered body fluid distribution and osmoregulation after HSD compared to controls. Our results might indicate reduced interstitial sodium accumulation capacity in HME, leading to ICFV increase. Therefore, this study provides additional support that HS is crucial for maintaining constancy of the internal environment.

Comparative Impact of Isolated Ultrafiltration and Hemodialysis on Fluid Distribution: A Bioimpedance Study

Introduction: Isolated ultrafiltration (IUF) is an alternative treatment for diuretic-resistant patients with fluid retention. Although hemodialysis (HD) predominantly decreases extracellular water (ECW), the impact of IUF on fluid distribution compared with HD remains unclear. Methods: We compared the effect of HD (n = 22) and IUF (n = 10) sessions on the body fluid status using a bioimpedance analysis device (InBody S10). Results: The total ultrafiltration volume was similar between HD and IUF (HD 2.5 ± 0.3 vs. ICF 2.1 ± 0.3 L/session, p = 0.196). The reduction rate of ECW was significantly higher than that of intracellular water (ICW) after HD (ECW −7.9% ± 0.8% vs. ICW −3.0% ± 0.9%, p < 0.001) and IUF (ECW −5.8% ± 0.9% vs. ICW -3.6% ± 0.8%, p = 0.048). However, the change in the ratio of ECW to total body water in HD was significantly larger than that in IUF (HD −3.2% ± 0.3% vs. ICF −1.1% ± 0.4%, p < 0.001). The reduction rates in serum tonicity (effective osmolality) were higher after HD than after IUF (HD −1.8% ± 0.5% vs. IUF −0.6% ± 0.2%, p = 0.052). Among the components of effective osmolality, the reduction rates of serum K⁺ and glucose levels after HD were significantly higher than those after IUF (serum K⁺: HD −30.5% ± 1.6% vs. IUF −0.5% ± 3.8%, p < 0.001; serum glucose: HD −15.4% ± 5.0% vs. IUF 0.7% ± 4.8%, p = 0.026), while the serum Na⁺ level was slightly and similarly reduced (HD −0.8% ± 0.4% vs. IUF −0.8% ± 0.4%, p = 0.500). The reduction in the osmolal gap value (measured osmolality–calculated osmolarity) was significantly greater after HD sessions than after IUF sessions (HD −12.4 ± 1.4 vs. IUF 2.0 ± 1.0 mOsm/kg, p = 0.001). Conclusion: The extracellular fluid reduction effect of HD is stronger than that of IUF. The different changes in effective osmolality and osmolal gap after HD and IUF sessions may be related to the different effects of HD and IUF on fluid distribution.

Fluid Rate Is Important As Much As Fluid Tonicity: An Experimental Study.

There is no study evaluating the effect on plasma osmolality of both fluid tonicity and high fluid rate at the same time. The aim of this experimental study was to determine the change in the plasma osmolality by different fluid tonicity and rate, and to suggest the safest and the most appropriate fluids based on the plasma osmolality for medical situations requiring fluid therapy with high or maintenance rates. The rats were randomly divided into seven groups (six rats in each group): [D5] D5 administered at 100 ml/kg/24h; [D5150] D5 administered at 150 ml/kg/24h; [D5(½)100] D5 0.45% NaCl administered at 100 ml/kg/24h; [D5(½)150] D5 0.45% NaCl administered at 150 ml/kg/24h; [D5(1)100] D5 0.9% NaCl administered at 100 ml/kg/24h; [D5(1)150] D5 0.9% NaCl administered at 150 ml/kg/24h; [Control group] non-treated control rats. Intracardiac blood samples were collected from all the groups at the end of 24 h. [D5(1)150] and [D5(½)100] were the group closest to the control group in terms of both sodium (P = .937; P = .699, respectively) and effective osmolality (P = 1, P = .818, respectively). Our results showed that 0.9% NaCl and 0.45% NaCl solutions might be the safest and the most appropriate fluids to maintain normal plasma osmolality in medical situations requiring fluid therapy with high or maintenance rates, respectively.

Hyperglycemic Emergencies in Minority Children and Adolescents With Diabetes Mellitus

Abstract Introduction: Hyperglycemic emergencies in children with diabetes traditionally include diabetic ketoacidosis (DKA) predominantly associated with T1DM, whereas hyperosmolar hyperglycemic state (HHS) that is associated with relative insulin deficiency in T2DM, rarely occurs (2%). There have been increasing reports of mixed DKA-HHS affecting up to 27%. The purpose of this study is to identify clinical features, risk factors, complications and outcomes among minority children presenting with hyperglycemic emergencies at our center. Methods: This is a retrospective chart review of children and adolescents (ages 1-21 years) admitted for hyperglycemic emergencies including DKA [defined as glucose &amp;gt;200 mg/dL, metabolic acidosis (pH &amp;lt;7.3 or serum bicarbonate &amp;lt;15 mmol/L) and ketonemia (ß-hydroxybuyrate ≥3 mmol/L) or moderate to large ketonuria], or HHS [defined as glucose &amp;gt;600 mg/dL, effective serum osmolality &amp;gt;320 mOsm/kg, venous pH &amp;gt;7.25 or arterial pH &amp;gt;7.30 or serum bicarbonate &amp;gt;15 mmol/L, absent to mild ketonemia] or mixed DKA-HHS between 2004 and 2019. Descriptive statistics, chi-squared analysis and t-tests were used. Results: Of 322 patients, 92% were African American with mean age 13.6 ± 3.5 years, 39% males, consisting of 266 (83%) with DKA, 52 (16%) mixed DKA-HHS, and 4 (1%) HHS. Ninety-eight of the DKA and DKA-HHS groups had T1DM. All 4 patients with HHS had T2DM. Compared to the DKA group, the mixed DKA-HHS group required higher IV fluids rates (p&amp;lt;0.0001), 4.3-fold greater odds of acute kidney injury (AKI, mean serum creatinine of 1.6 mg/dl vs 1.1 mg/dl; ref 0.5-1.0 mg/dL) and 3.3-fold greater odds of developing altered mental status (AMS). Risk factors such as insulin adherence, and precipitating factors like infection or stress were not different between both groups (p=0.06). There was no significant difference in insulin rates or time to resolution (p=0.4) in both groups. Among the HHS group, 50% presented with AMS and AKI (mean Cr 1.1 mg/dl ± 0.31) due to severe dehydration and required higher IV fluids rates (≥2 x maintenance). Creatinine kinase in 2 patients were slightly elevated (mean 1643 units/L, ± 77; ref 39-309). Insulin drip at 0.05 u/kg/hour was started in all 4 patients. None had venous thrombosis, rhabdomyolysis, cerebral edema, or death. Average time of resolution was 10 ±1.63 hours. Conclusion: In this study, 16% of patients with hyperglycemic emergencies presented with mixed DKA-HHS which was associated with more complications compared to the DKA group. Serum osmolality should be calculated and checked at diagnosis. Identification of hyperosmolality whether with or without DKA in the emergency setting is important because treatment should be focused on the degree of dehydration (usually moderate to severe) and other complications such as AKI and mental status changes.

Normal versus half-normal saline in the treatment of children with diabetic ketoacidosis

ObjectiveThis study aims to determine the effect of 0.9% saline (NS) versus 0.45% saline (half NS) on blood pressure and serum electrolytes in children with diabetic ketoacidosis.Patients and methodsThis is a cross-sectional prospective comparative study carried out on 105 patients (1–18 years) from those admitted to the pediatric ICU of Al-Zahraa University Hospital from March 2017 to August 2019. Cases were divided into three groups (35 in each group). Group I patients received a shock, deficit, and maintenance therapy with NS. Group II patients received a shock therapy NS along with deficit and maintenance therapy with half NS. Group III patients received a shock, deficit, and maintenance therapy with half NS.ResultsThere were no hypotensive cases among all patients. There was a significant decrease in mean arterial blood pressure in the three groups after treatment. There was a significant increase in serum corrected sodium level in group I after treatment, whereas there was a significant decrease in its level in groups II and III. Serum potassium level showed an insignificant decrease after treatment in all groups. Blood glucose level significantly decreased after treatment in the same group, but in comparison with other groups, the differences were insignificant. Serum osmolality significantly decreased after treatment in all groups. pH significantly increased after treatment in each group, but in a comparison between groups, there were insignificant differences. Group I had the longest pediatric ICU stay.ConclusionsOur patients continue to maintain normal or even have higher blood pressure levels with no hypotensive cases. The mean arterial blood pressure significantly decreased after treatment with intravenous fluids, especially in the group that received half NS. Rehydration with half NS results in decreased corrected sodium and more decrease in effective serum osmolality.

Clinical profiles, outcomes and risk factors among type 2 diabetic inpatients with diabetic ketoacidosis and hyperglycemic hyperosmolar state: a hospital-based analysis over a 6-year period

ObjectiveDiabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS) are the two most common hyperglycemic emergencies (HEs) associated with diabetes mellitus. Individuals with HEs can present with combined features of DKA and HHS. The objective of this study is to assess the clinical characteristics, therapeutic outcomes, and associated predisposing factors of type 2 diabetic patients with isolated or combined HEs in China.MethodsWe performed a retrospective analysis of 158 patients with type 2 diabetes (T2DM), complicated with DKA, HHS, or DKA combined with HHS (DKA-HHS) in Shanghai Tongji Hospital, China from 2010 to 2015. Admission clinical features, therapeutic approaches and treatment outcomes of those patients were extracted and analyzed.ResultsOf the 158 patients with T2DM, 65 (41.1%) patients were DKA, 74 (46.8%) were HHS, and 19 (12.0%) were DKA-HHS. The most common precipitants were infections (111, 70.3%), newly diagnosed diabetes (28,17.7%) and non-compliance to medications (9, 5.7%). DKA patients were divided into mild, moderate and severe group, based on arterial blood gas. Spearman correlation analysis revealed that C-reaction protein (CRP) was positively correlated with severity of DKA, whereas age and fasting C peptide were inversely correlated with severity of DKA (P < 0.05). The mortality was 10.8% (17/158) in total and 21.6% (16/74) in the HHS group, 5.9% (1/17) in DKA-HHS. Spearman correlation analysis indicated that death in patients with HHS was positively correlated to effective plasma osmolality (EPO), renal function indicators and hepatic enzymes, while inversely associated with the continuous subcutaneous insulin infusion (CSII) therapy. Logistic regression analysis suggested that elevated blood urea nitrogen (BUN) on admission was an independent predisposing factor of mortality in HHS, while CSII might be a protective factor for patients with HHS. Furthermore, the receiver-operating characteristic (ROC) curve analysis indicated that BUN had the largest area under the ROC curves for predicting death in patients with HHS.ConclusionsOur findings showed elevated CRP and decreased fasting C-peptide might serve as indicator for severe DKA. Elevated BUN might be an independent predictor of mortality in patients with HHS, whereas CSII might be a protective factor against death in HHS.

A method for measuring intra-tissue swelling pressure using a needle micro-osmometer.

The intervertebral disc’s ability to resist load and facilitate motion arises largely from osmotic swelling pressures that develop within the tissue. Changes in the disc’s osmotic environment, diurnally and with disease, have been suggested to regulate cellular activity, yet knowledge of in vivo osmotic environments is limited. Therefore, the first objective of this study was to demonstrate proof-of-concept for a method to measure intra-tissue swelling pressure and osmolality, modeling micro-osmometer fluid flux using Darcy’s law. The second objective was to compare flux-based measurements of the swelling pressure within nucleus pulposus (NP) tissue against ionic swelling pressures predicted by Gibbs-Donnan theory. Pressures (0.03–0.57 MPa) were applied to NP tissue (n = 25) using equilibrium dialysis, and intra-tissue swelling pressures were measured using flux. Ionic swelling pressures were determined from inductively coupled plasma optical emission spectrometry measurements of intra-tissue sodium using Gibbs-Donnan calculations of fixed charge density and intra-tissue chloride. Concordance of 0.93 was observed between applied pressures and flux-based measurements of swelling pressure. Equilibrium bounds for effective tissue osmolalities engendered by a simulated diurnal loading cycle (0.2–0.6 MPa) were 376 and 522 mOsm/kg H2O. Significant differences between flux and Gibbs-Donnan measures of swelling pressure indicated that total tissue water normalization and non-ionic contributions to swelling pressure were significant, which suggested that standard constitutive models may underestimate intra-tissue swelling pressure. Overall, this micro-osmometer technique may facilitate future validations for constitutive models and measurements of variation in the diurnal osmotic cycle, which may inform studies to identify diurnal- and disease-associated changes in mechanotransduction.

Clinical Outcomes in Patients With Isolated or Combined Diabetic Ketoacidosis and Hyperosmolar Hyperglycemic State: A Retrospective, Hospital-Based Cohort Study.

Many patients with hyperglycemic crises present with combined features of diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS). The implications of concomitant acidosis and hyperosmolality are not well known. We investigated hospital outcomes in patients with isolated or combined hyperglycemic crises. We analyzed admissions data listing DKA or HHS at two academic hospitals. We determined 1) the frequency distributions of HHS, DKA, and combined DKA-HHS (DKA criteria plus elevated effective osmolality); 2) the relationship of markers of severity of illness and clinical comorbidities with 30-day all-cause mortality; and 3) the relationship of hospital complications associated with insulin therapy (hypoglycemia and hypokalemia) with mortality. There were 1,211 patients who had a first admission with confirmed hyperglycemic crises criteria, 465 (38%) who had isolated DKA, 421 (35%) who had isolated HHS, and 325 (27%) who had combined features of DKA-HHS. After adjustment for age, sex, BMI, race, and Charlson Comorbidity Index score, subjects with combined DKA-HHS had higher in-hospital mortality compared with subjects with isolated hyperglycemic crises (adjusted odds ratio [aOR] 2.7; 95% CI 1.4, 4.9; P = 0.0019). In all groups, hypoglycemia (<40 mg/dL) during treatment was associated with a 4.8-fold increase in mortality (aOR 4.8; 95% CI 1.4, 16.8). Hypokalemia ≤3.5 mEq/L was frequent (55%). Severe hypokalemia (≤2.5 mEq/L) was associated with increased inpatient mortality (aOR 4.9; 95% CI 1.3, 18.8; P = 0.02). Combined DKA-HHS is associated with higher mortality compared with isolated DKA or HHS. Severe hypokalemia and severe hypoglycemia are associated with higher hospital mortality in patients with hyperglycemic crises.

P: 43 A Sensitive and Convenient Protocol for Determining Brain Water Content in Rats using a Moisture Analyzer

BACKGROUND: Brain water content represents a major endpoint in studies of hepatic encephalopathy and liver failure.1 However, none of the current methods for evaluating brain water content fulfills the ideal requirements of a measuring technique, being complex, expensive, lengthy, qualitative or insensitive.2 Our AIM was to evaluate a novel protocol for measuring brain water content using a moisture analyzer in a rodent model of hyponatremia-induced brain edema. METHODS: Female Sprague-Dawley rats (248 ± 41 g bw) undergoing a 3-hour protocol for inducing hyponatremia-related brain edema (HypoNa group) were compared with a group of normonatremic rats (Control group). All rats were anesthetized with sevoflurane and mechanically ventilated. Body temperature was maintained at 37 ºC and major physiological parameters (heart rate, oxygen saturation, mean arterial pressure) were monitored. Acute hyponatremia was induced by administering desmopressin (DDAVP 1 ug/rat s.c.) and two i.p. injections of 140 mmol/L glucose solution (an injection of 12% of b.w. at the beginning and of 6% of b.w. 30 minutes later). At the end of the experiments, blood was collected from aorta, the rats were decapitated, and the brain was quickly dissected. Frontal cortex was immediately frozen and stored in liquid nitrogen. The frontal cortex was pulverized frozen with a metal mortar, and the frozen powder was placed in a moisture analyzer (MB120, Ohaus Corporation) between two glass-fiber filters for measuring water content by the wet-to-dry weight method. Dry weight (g) was determined when there was no change in 1 mg for 3 minutes. RESULTS: Compared with the Control group, rats in the HypoNa group presented lower sodium (134.0 ± 1.0 vs. 104.8 ± 1.0 mmol/L, P &lt; 0.0001), calcium (1.27 ± 0.04 vs. 1.15 ± 0.03 mmol/L, P &lt; 0.05), and effective osmolality (281.2 ± 2.10 vs. 229.8 ± 3.8 mOsm/L, P &lt; 0.0001), and a trend to increased concentrations of potassium (4.10 ± 0.15 vs. 4.75 ± 0.40 mmol/L, P = 0.25) and lactate (2.23 ± 0.38 vs. 6.23 ± 2.18 mmol/L, P = 0.22) in plasma. Frontal cortex water content was higher in the HypoNa group (Control: 82.20 ± 0.74 vs. HypoNa: 85.01 ± 0.97 %, P &lt; 0.01). Measuring time of water content using the moisture analyzer was &lt;15 minutes per sample. CONCLUSIONS: These results suggest that the present protocol using a moisture analyzer is a convenient and sensitive method for measuring brain water content in rats.

Background characteristics and clinical features of elderly patients with hyperglycemic hyperosmolar syndrome.

Few reports have described the characteristics of hyperglycemic hyperosmolar syndrome (HHS) in the elderly. We investigated the background characteristics and clinical features of 14 elderly patients with HHS. HHS was diagnosed based on a blood glucose level of >600 mg/dL and an effective plasma osmolality [2 (Na) + glu/18] of >320 mOsm/kg. For 14 cases of HHS, we investigated the medical and social backgrounds of the patients, their clinical findings, and the outcomes. The mean patient age was 83 years, and the mean body mass index was 17.8 kg/m2. Half had a history of either cerebral infarction or hip fracture. The mean duration of diabetes was 14 years, but 4 diabetes cases were newly diagnosed. There was a high prevalence of acute infection (79%) in HHS patients, especially urinary tract infection and pneumonia, with a seasonal peak in winter. Patients who had been treated with steroids, tube feeding, or both numbered 1, 2, and 1, respectively. Most HHS patients had a history of dementia. More than half of such patients were living alone or only with their spouse, and their activities of daily living showed marked deterioration. The mean blood glucose level, HbA1c, effective serum osmolality, and pH were 881 mg/dL, 10.3%, 353 mOsm/kg, and 7.39, respectively. One patient died during hospitalization, and 9 were discharged to nursing homes or other hospitals. The mean length of hospitalization was 55 days. In most cases, the insulin secretion capacity was preserved, and 9 patients were treatable with oral hypoglycemic agents alone. Many cases of HHS in the elderly are associated with infection, a shortage of social support, cognitive impairment, or ADL decline. Although the survival rate in our series was high, the functional prognosis was impaired.

Approach to the Treatment of Diabetic Ketoacidosis

Diabetic ketoacidosis (DKA), a common cause of severe metabolic acidosis, remains a life-threatening condition due to complications of both the disease and its treatment. This Acid-Base and Electrolyte Teaching Case discusses DKA management, emphasizing complications of treatment. Because cerebral edema is the most common cause of mortality and morbidity, especially in children with DKA, we emphasize its pathophysiology and implications for therapy. The risk for cerebral edema may be minimized by avoiding a bolus of insulin, excessive saline resuscitation, and a decrease in effective plasma osmolality early in treatment. A goal of fluid therapy is to lower muscle venous Pco2 to ensure effective removal of hydrogen ions by bicarbonate buffer in muscle and diminish the binding of hydrogen ions to intracellular proteins in vital organs (such as the brain). In patients with DKA and a relatively low plasma potassium level, insulin administration may cause hypokalemia and cardiac arrhythmias. It is suggested in these cases to temporarily delay insulin administration and first administer potassium chloride intravenously to bring the plasma potassium level close to 4mmol/L. Sodium bicarbonate administration in adult patients should be individualized. We suggest it be considered in a subset of patients with moderately severe acidemia (pH<7.20 and plasma bicarbonate level< 12mmol/L) who are at risk for worsening acidemia, particularly if hemodynamically unstable. Sodium bicarbonate should not be administered to children with DKA, except if acidemia is very severe and hemodynamic instability is refractory to saline administration.

Determination of tonicity effects of ketoacids and lactate by use of two canine red blood cell assays.

To determine the tonicity effects of β-hydroxybutyrate, acetoacetate, and lactate in canine RBCs. RBCs from approximately 40 dogs. 2 in vitro methods were used to conduct 4 experiments. The modified osmotic fragility assay was used to measure the ability of ketoacid salts added to serial sucrose dilutions to protect RBCs from osmotic hemolysis. In a second assay, a handheld cell counting device was used to measure changes in RBC diameter to assess the tonicity effect of solutions of ketoacid and lactate salts. For the modified osmotic fragility assay, all ketoacid salts had an osmoprotective effect, but the effect was determined to be completely attributable to the tonicity effect of added cations (sodium and lithium) and not the ketoacid moieties. However, both the sodium and lithium lactate salts provided osmoprotection attributable to both the cation and lactate anion. For the second assay, RBC diameter was significantly increased with the addition of urea (an ineffective osmole) but did not change with the addition of glucose (an effective osmole), which established the behaviors of ineffective and effective osmoles in this assay. The RBC diameter was significantly increased over that of control samples by the addition of sodium β-hydroxybutyrate, lithium acetoacetate, and lithium lactate but was decreased by the addition of sodium lactate. For both assays, β-hydroxybutyrate and acetoacetate acted as ineffective osmoles, whereas lactate acted as an effective osmole in 3 of 4 experiments.

Hyperosmolar hyperglycemic state: a historic review of the clinical presentation, diagnosis, and treatment.

The hyperosmolar hyperglycemic state (HHS) is the most serious acute hyperglycemic emergency in patients with type 2 diabetes. von Frerichs and Dreschfeld described the first cases of HHS in the 1880s in patients with an "unusual diabetic coma" characterized by severe hyperglycemia and glycosuria in the absence of Kussmaul breathing, with a fruity breath odor or positive acetone test in the urine. Current diagnostic HHS criteria include a plasma glucose level >600 mg/dL and increased effective plasma osmolality >320 mOsm/kg in the absence of ketoacidosis. The incidence of HHS is estimated to be <1% of hospital admissions of patients with diabetes. The reported mortality is between 10 and 20%, which is about 10 times higher than the mortality rate in patients with diabetic ketoacidosis (DKA). Despite the severity of this condition, no prospective, randomized studies have determined best treatment strategies in patients with HHS, and its management has largely been extrapolated from studies of patients with DKA. There are many unresolved questions that need to be addressed in prospective clinical trials regarding the pathogenesis and treatment of pediatric and adult patients with HHS.

In vitro increase of mean corpuscular volume difference (dMCV) as a marker for serum hypertonicity in dogs

Spurious increase in erythrocyte mean corpuscular volume (MCV) on automated cell analyzers is a well-characterized lab error in hypertonic patients. A difference between automated and manual MCV (dMCV) greater than 2 fl has been shown to predict hypertonicity in humans. The purpose of this study was to investigate dMCV as a marker for serum hypertonicity in dogs and to examine the relationship between dMCV and three methods of estimating serum tonicity: measured (OsMM), calculated (OsMC), and calculated effective (OsMCE) osmolalities. OsMC, OsMCE, and dMCV were calculated from routine blood values and OsMM was directly measured in 121 dogs. The dMCV of hypertonic dogs was significantly larger than that of normotonic dogs for all three osmolality methods. dMCV predicted hypertonicity as estimated by OsMM better than it predicted hypertonicity as estimated by OsMC and OsMCE. A cutoff of 2.96 fl yielded the best sensitivity (76%) and specificity (71%) for hypertonicity estimated by OsMM.

Type 1 Diabetes in Children and Adolescents

Type 1 Diabetes in Children and Adolescents