Free Water Intake Research Articles

7422 Adipsic Diabetes Insipidus Following Pituitary Macroadenoma Resection

Abstract Disclosure: J. Chippior: None. L. Ghalib: None. A 44 year-old female with a PMH of primary hypothyroidism, and a pituitary macroadenoma that was lost to follow up, presented to the ED with a chief complaint of an acute headache and decreased visual acuity involving the right eye over the past year. Patient was found to have a large, homogenous suprasellar mass with the largest dimension measuring 6.3 cm in size, and causing displacement of the optic chiasm. Initial hormonal workup was most notable for elevated prolactin at 128 ng/ml (3.3-26.7 ng/ml), which was slightly lower than when it was previously measured 10 years ago. The patient was taken to the OR for transsphenoidal endoscopic partial resection, but within 24 hours of post-op, she developed hypernatremia at 153 mmol/dL (135-145 mmol/dL) that was suspected to be secondary to diabetes insipidus (DI). In addition, she also suffered several small strokes involving her right midbrain and basal ganglia. She required multiple doses of DDAVP throughout her stay and this was ultimately continued upon discharge. Unfortunately, as follow up MRI had shown residual tumor within the third ventricle, she returned for a 2nd resection but once again suffered additional post-operative complications. The patient experienced additional strokes involving the right frontal and parietal lobes, and her DI became more labile than before, with her serum sodium peaking at 172 mmol/dL. Despite such a high degree of hypernatremia, she did not demonstrate any signs of thirst or any desire to access free water, even after her post-stroke encephalopathy had largely resolved. With less than 100 severe cases documented over the past four decades, it was suspected that the patient had a rare form of DI known as “adipsic DI”. Osmoreceptors within the hypothalamus can trigger the release of ADH or stimulate thirst, with the former requiring a smaller change in serum osmolality to generate such a response. Pituitary surgery involves manipulation of the infundibulum and any inadvertent severing can prevent ADH’s ability to travel from the hypothalamus to the posterior pituitary, subsequently leading to DI. The majority of patients with post-op DI increase their free water intake and subsequently do not develop hypernatremia. Those with adipsic DI lack this compensatory mechanism which leads to the electrolyte disturbance, and carries a higher risk of morbidity and mortality than those with typical DI. Following her second surgery, our patient was discharged with DDAVP once again but this time with a higher dose and frequency. She’s had numerous hospital readmissions since then for altered mental status in the setting of hypernatremia as she still struggles to meet her free water intake and continuously relies on her family for reminders. Though her case is certainly not typical, it highlights the added complexity of managing adipsic DI as it relies not only on DDAVP replacement, but replicating what is supposed to be an innate behavior. Presentation: 6/3/2024

8431 Triphasic response of pituitary stalk post anoxic injury in a mechanically ventilated patient

Abstract Disclosure: P. Henriquez Feliz: None. H. Neizer: None. E. Alshdifat: None. F. Abdulkarim: None. T. Mazhude: None. T. Zahra: None. Introduction: A phenomenon may manifest wherein the pituitary undergoes a triphasic response following an inciting event. Phases include diabetes insipidus (DI) followed by Syndrome of inappropriate Antidiuretic Hormone (ADH), and finally a recurrence of DI. Research has established that this is a common complication to neurosurgical interventions but there are limited reports following anoxic brain injury. This case demonstrates a potential pituitary stalk injury after an anoxic brain injury. Case: Unknown 30 year old male found by EMS with pulseless electrical activity cardiac arrest likely from polysubstance use. Returned of spontaneous circulation after 30 minutes in the emergency department. Total downtime unknown. Managed by Intensive Care Unit. Scans were negative. Initial blood work showed eunatremia with a specific gravity (sg) 1.068 and serum osmolarity (Sosm) 311. Eventually, developed hypernatremia, 163 mmol/L, and a urine osmolarity (Uosm) of 428 mosm, raising concern for central DI (CDI). Responded to hypotonic fluids not requiring desmopressin at that time. On day 10, developed severe hyponatremia 113 mmol/L with a Uosm of 774, suggesting ADH mediated response or excessive free water intake. Sodium normalized after managed with fluid restriction. On day 16, patient developed hypernatremia, 178 mmol/L, and Uosm of 869 mosm. Suggestive of CDI recurrence. Treated with desmopressin and hydrocortisone. Discussion: Changes in water-electrolyte balances may occur after anoxic brain injury. The mechanism is believed to arise from axonal shock due to disruptions in vascular supply leading to unregulated release of ADH from degenerating posterior pituitary, causing oliguria and hyponatremia, and subsequent permanent DI from loss of neurons. These stages may last 5-7 days on initial phase, and the second phase can extend anywhere from 2-14 days. In this case, phases one and two lasted four and three days, respectively. It is important to acknowledge that timelines may vary based on management initiation and recognition of transition between stages. CDI treatment involves hypotonic fluids with desmopressin. Our patient was initially managed with free water due to low suspicion for CDI. During shift towards suspected second phase, Uosm increased, urine output and sodium dropped significantly. However, it is uncertain whether this was due to axonal injury causing SIADH or a consequence of hypotonic fluids causing increased response of ADH. As predicted during triphasic response, patient became oliguric with a net negative fluid balance of >10L and Uosm of 869. Therefore, desmopressin was started with good response. Further follow up was unattainable as neurological status deteriorated preceding to brain death. Most cases reported showed hypoattenuation lesion of posterior pituitary on MRI; MRI would have been required to determine if there was injury to the pituitary in this case. Presentation: 6/2/2024

A protocolized five strategies in open repair for ruptured abdominal aortic aneurysm.

Although the medical field has made significant progress, there has been little improvement in the survival rate of patients with ruptured abdominal aortic aneurysms (rAAAs). We implemented a protocol consisting of five strategies in the management of rAAA patients who underwent open repair surgery. The protocol comprised the following strategies: intentional hypotension <70mmHg, lung first and kidney last policy (restricted fluid resuscitation and permissive oligoanuria), immediate postoperative extubation, free-water intake with active ambulation, and open abdomen with the routine second-look operation. The study included 13 patients (11 male) with a mean age of 75.5 ± 7.4 (range: 58-87) years who underwent the procedure from 2016 to 2018, with a mean follow-up of 40.1 ± 9.04 months. Five deteriorating to hemodynamic shock and decreased consciousness requiring intubation and ventilation prior to surgery were observed. Two of these patients required preoperative cardiopulmonary resuscitation (CPR). All patients regained consciousness after surgery, including the two patients who required cardiopulmonary resuscitation. Immediate postoperative extubation was performed in nine patients, but two (22.2%) of them needed re-intubation due to ventilation/perfusion mismatch. Four patients underwent continuous renal replacement therapy, with three of them having anuria for up to 48h after surgery. Two of these patients made a full recovery. Daily ambulation was carried out for a mean of 4.77 ± 3.5 (range 1-13) days with an open abdomen, during which no significant events were reported. Four cases of colon ischemia/necrosis were identified in the second-look operation, with two patients requiring Hartman's procedure and the other two undergoing left colon partial resection. There were two in-hospital mortalities (15.4%). A protocol-based approach, through multidisciplinary team consensus and the development of optimal surgical strategies, could improve clinical outcomes for patients undergoing emergency surgery for rAAA. Further studies with larger sample sizes are needed to refine the protocols.

Modeling the effect of ambient temperature on reticulorumen temperature, and drinking and eating behaviors of late-lactation dairy cows during colder seasons

Dairy cows may suffer thermal stress during the colder seasons especially due to their open-air housing systems. Free water temperature (FWT) and feed temperature (FT) are dependent on ambient temperature (AT) and can be critical for maintaining body and reticulorumen temperature (RT) in cold conditions. The objective of this study was to determine the effects of FWT and FT on RT fluctuations, and of AT on RT and drinking and eating behaviors in late-lactation cows during cold exposure. Data were collected from 16 multiparous lactating cows for four 6-d periods during the autumn and winter seasons. The cows (224 ± 36 days in milk; mean ± SD) had an average milk yield (MY) of 24.8 ± 4.97 kg/d and RT of 38.84 ± 0.163 °C. Daily average AT ranged from 4.38 to 17.25 °C. The effects of the temperature and amount of the ingested water or feed on RT change and recovery time, and the effect of the daily AT on RT, feed and water intake, and drinking, eating, and rumination behaviors were analyzed using the generalized additive mixed model framework. Reticulorumen temperature change and recovery time were affected by FWT (+0.0596 °C/°C and −1.27 min/°C, respectively), but not by FT. The amount of the ingested free water and feed affected RT change (−0.108 °C/kg drink size and −0.150 °C/kg meal size, respectively), and RT recovery time (+2.13 min/kg drink size and + 3.71 min/kg meal size, respectively). Colder AT decreased RT by 0.0151 °C/°C between 9.91 and 17.25 °C AT. Cows increased DM intake (DMI) by 0.365 kg/d per 1 °C drop in AT below 10.63 °C, but with no increase in MY. In fact, MY:DMI decreased by 0.0106/°C as AT dropped from 17.25 to 4.38 °C. Free water intake (FWI) was reduced by 0.0856 FWI:DMI/°C as AT decreased from 17.25 to 8.27 °C. Cold exposure influenced animal behavior with fewer drink and meal bouts (−0.432 and −0.290 bouts/d, respectively), larger drink sizes (+0.100 kg/bout), and shorter rumination time (−5.31 min/d) per 1 °C decrease in AT from 17.25 °C to 8.77, 12.53, 4.38, and 10.32 °C, respectively. In conclusion, exposure to low AT increased feed intake, reduced water intake, and changes in eating, drinking and rumination behaviors of dairy cows in late lactation. Additionally, the consequences of cold exposure on cows may be aggravated by ingestion of feed and free water at temperatures lower than the body, potentially impacting feed efficiency due to the extra energetic cost of thermoregulation.

Hypernatremia and Its Rate of Correction: The Evidence So Far.

Hypernatremia or high serum sodium levels can have many different causes, includinginsufficient free water intake, or excess free water losses. The management of hypernatremia focuses on resolving the underlying cause, replenishing free water deficit, and preventing further losses while closely monitoring serum sodium concentration. This systematic review was carried outusing medical databases such as PubMed, PubMed Central, and Google Scholar for relevant medical literature. The identified articles were reviewed, eligibility criteria were applied, and seven research articles were identified. The effect of the rate of hypernatremia correction on both short- and long-term outcomes in volume-resuscitated patients was the focus of our search for randomized or observational studies. Based on our analysis of the clinical evidence, we concluded that the present recommendations for treating acute and chronic hypernatremia in resuscitated patients do not stem from high-quality research.

Ruggedness test made with mortars by free water intake test

Capillary movement in porous building materials is modelled by unsaturated flow. Material property needed for the calculations is liquid water diffusivity which is usually estimated by water absorption coefficient and capillary saturation moisture content. While determining of water absorption coefficient can be done according to EN-ISO 15148:2002 there is still lack of knowledge about sources of uncertainty in the experiment. In this paper author presents results of ruggedness tests done with mortar. The sources of errors investigated here was the shape and water inflow area of the specimen. Some specimens were also deprived of side sealing and sealing of upper surface as it was known to have impact on results. Results shows there is no considerable impact on measured capillary properties if the specimen sides are sealed or not. Nor does affect the immersed surface area of the specimen. The shape of the immersed surface instead has significant impact on values of both water absorption coefficient and capillary saturation of the specimen.

Levels of leucaena hay associated with cactus pear in diets for crossbred steers.

Our hypothesis is that the total replacement of ground corn grain (GCG) by cactus pear (CP) in association with 70% of leucaena hay (LH) increases dry matter (DM) intake and digestibility and nitrogen metabolism and maintains the feeding behavior of cattle. The objective was to evaluate the effects of inclusion of these feeds on the nutritional parameters and nitrogen metabolism of cattle. Eight steers, average age of 12 months, weight of 267.5 ± 15 kg, were distributed into two simultaneous 4 × 4 Latin squares according to a 2 × 2 factorial scheme, in which the first factor evaluated was different proportions of inclusion of LH (50 or 70% DM basis), and the second factor was the total replacement of GCG with CP. There was lower DM intake in animals fed with 70% LH. There was an interaction between the factors for DM digestibility, in which the animals fed CP did not differ regardless of the inclusion of LH, but for animals without CP, the greater inclusion of LH decreases DM digestibility. The inclusion of CP decreased free water intake. There was an interaction for total water intake (WI), in which the animals fed without CP presented similarity for this, while in the inclusion of CP, the animals fed 70% of LH presented higher WI. Also, lower values of chewing were observed for animals fed with CP. The replacement of GCG with CP improves the efficiency of nitrogen utilization in the rumen. The inclusion of 70% LH depresses intake.

Classifying Hypotonic Hyponatremia by Projected Treatment Effects - A Quantitative 3-Dimensional Framework

The diagnostic algorithms currently used for hypotonic hyponatremia focus primarily on impaired urinary dilution and often neglect the influence of free water intake and solute excretion. We hypothesized that, in each case of hypotonic hyponatremia different pathophysiological mechanisms play a role simultaneously. Using clinical data of the previous observational Co-Med study, we defined each case of hypotonic hyponatremia concurrently in 3 dimensions as follows: (i) high net free water intake (HNFWI), (ii) impaired dilution of the urine (IDU), and (iii) low nonelectrolyte solute excretion (LNESE). For each dimension, a "standard delta sodium" (sdna) was calculated reflecting the expected difference to the serum sodium concentration, that would result from changing a dimension to a specific and equivalent target level. Results from 279 patients were used for this analysis. With target levels of free water intake and urine osmolality at the fifth percentile, and nonelectrolyte solute excretion at the 95th percentile, median (interquartile range) sdna values were 7.1 (4.8-10.2) for HNFWI, 11.8 (7.0-18.6) for IDU and 2.6 (1.6-4.2) mmol/l per 24 hours for LNESE. Sdna results in individual patients were highest with IDU in 68.5%, HNFWI in 30.8% and 0.7% with LNESE. At an sdna-level of at least 4mmol/l per 24 hours, the prevalence of HNFWI was 78.9%, IDU 87.1%, and LNESE 26.5%. 77.5% of patients had 2 or all 3 mechanisms present. Hyponatremia was mostly multifactorial in subgroups according to classic categories of hyponatremia and typical comorbidities as well. Hypotonic hyponatremia can be quantitatively defined by 3 dimensions. Most cases should be considered multifactorial.

Reductions in the water supply to crossbred Santa Inês ewes in the Brazilian semi-arid: Apparent nutrient digestibility, water and nitrogen balance, and performance

SummaryThis study aimed to evaluate the intake and nutrient digestibility, water, and nitrogen balance of Santa Inês crossbred ewes under confinement receiving reductions in the water supply. Thirty-two Santa Inês crossbred ewes, at an average body weight of 32.2 ± 7.4 kg and age of 2.3 ± 0.99 years, were distributed in a completely randomized design, with four treatments, and eight animals per treatment, the treatments were 100%, 80%, 60%, and 40% of ad libitum water. Nutrient intake and digestibility, water and nitrogen balance, and performance were evaluated. The reductions in the water supply did not promote significant alterations, in the nutrient intake, or apparent digestibility of the animals (P > 0.05). A linear decreasing effect was observed for free water intake (P < 0.001), total water intake (P < 0.001), total urine output (P = 0.008), water excreted via urine (P = 0.006), water excreted via feces (P = 0.006), total water losses (P < 0.001), water absorbed (P < 0.001), and nitrogen excreted via feces (P = 0.002). The water and nitrogen balance and performance were not influenced by water offers (P > 0.05). It was concluded that water offers of up to 40% of ad libitum intake, do not promote negative effects on intake and apparent nutrient digestibility, mineral intake, nitrogen balance, and water balance in Santa Inês ewes.

Protocolo diagnóstico y terapéutico de los trastornos del sodio

The term dysnatremia is applied to alterations in the concentration of sodium in the plasma. Changes in the concentration of sodium in the plasma may cause fluid displacements between intracellular and extracellular compartments, In a healthy individual the osmoregulatory system of the organism maintains the concentration of sodium from 135 to 145 mEq/l. An alteration in this system leads to an imbalance between the intake and excretion of free water. When the intake of free water surpasses excretion, the concentration of sodium in the plasma falls to below 135 mEq/l, a condition known as hyponatremia. On the contrary, hypernatremia, which is defined as a concentration of sodium in serum higher than 145 mEq/l, arises when the excretion of electrolyte-free water surpasses intake.

Modeling the effects of heat stress in animal performance and enteric methane emissions in lactating dairy cows

Heat stress (HS) negatively affects dry matter intake (DMI), milk yield (MY), feed efficiency (FE), and free water intake (FWI) in dairy cows, with detrimental consequences to animal welfare, health, and profitability of dairy farms. Absolute enteric methane (CH4) emission, yield (CH4/DMI), and intensity (CH4/MY) may also be affected. Therefore, the goal of this study was to model the changes in dairy cow productivity, water intake, and absolute CH4 emissions, yield, and intensity with the progression (days of exposure) of a cyclical HS period in lactating dairy cows. Heat stress was induced by increasing the average temperature by 15°C (from 19°C in the thermoneutral period to 34°C) while keeping relative humidity constant at 20% (temperature-humidity index peaks of approximately 83) in climate-controlled chambers for up to 20 d. A database composed of individual records (n = 1,675) of DMI and MY from 82 heat-stressed lactating dairy cows housed in environmental chambers from 6 studies was used. Free water intake was also estimated based on DMI, dry matter, crude protein, sodium, and potassium content of the diets, and ambient temperature. Absolute CH4 emissions was estimated based on DMI, fatty acids, and dietary digestible neutral detergent fiber content of the diets. Generalized additive mixed-effects models were used to describe the relationships of DMI, MY, FE, and absolute CH4 emissions, yield, and intensity with HS. Dry matter intake and absolute CH4 emissions and yield reduced with the progression of HS up to 9 d, when it started to increase again up to 20 d. Milk yield and FE reduced with the progression of HS up to 20 d. Free water intake (kg/d) decreased during the exposure to HS mainly because of a reduction in DMI; however, when expressed in kg/kg of DMI it increased modestly. Methane intensity also reduced initially up to d 5 during HS exposure but then started to increase again following the DMI and MY pattern up to d 20. However, the reductions in CH4 emissions (absolute, yield, and intensity) occurred at the expense of decreases in DMI, MY, and FE, which are not desirable. This study provides quantitative predictions of the changes in animal performance (DMI, MY, FE, FWI) and CH4 emissions (absolute, yield, and intensity) with the progression of HS in lactating dairy cows. The models developed in this study could be used as a tool to help dairy nutritionists to decide when and how to adopt strategies to mitigate the negative effects of HS on animal health and performance and related environmental costs. Thus, more precise and accurate on-farm management decisions could be taken with the use of these models. However, application of the developed models outside of the ranges of temperature-humidity index and period of HS exposure included in this study is not recommended. Also, validation of predictive capacity of the models to predict CH4 emissions and FWI using data from in vivo studies where these variables are measured in heat-stressed lactating dairy cows is required before these models can be used.

Multifactorial Hyponatremia: Don’t Miss Ruling Out Malignancy

A 62-year-old male with a history of chronic obstructive pulmonary disease(COPD), schizoaffective disorder treated with Zoloft, type 2 diabetes mellitus, and tobacco use presented with an acute on chronic hyponatremia of 120 mEq/L. He presented with only a mild headache and endorsed recently increasing his free water intake due to a cough. Labs and physical exam findings suggested a true, euvolemic hyponatremia. Polydipsia and Zoloft-induced syndrome of inappropriate antidiuretic hormone (SIADH) were determined to be likely contributors to his hyponatremia. However, given his tobacco use, further workup was done to rule out malignancy causing hyponatremia. Chest CT did ultimately suggest malignancy and further workup was recommended. With the hyponatremia treated, the patient was discharged with recommended outpatient workup. This case serves as a reminder to consider that hyponatremia may be multifactorial and even if there is a likely cause identified, malignancy should be ruled out in patients with risk factors.

Circadian rhythm shifts and alcohol access in adolescence synergistically increase alcohol preference and intake in adulthood in male C57BL/6 mice

BackgroundAdolescents have a natural tendency to be night owls, maintaining delayed circadian rhythms, and this rhythm is in direct conflict with the early wake times required during the school year. This leads to ‘social jetlag’, chronic circadian stress or desynchrony (CD) in which the rhythm of the intrinsic body clock is out of sync with behavior. CD increases alcohol intake in adolescents and adults, yet it is unknown whether adolescent CD also increases long-term addiction risk. The goal of this study was to determine whether adolescent alcohol intake in CD would increase adult alcohol preference and intake in male C57BL/6 J mice. Methods: We measured free access alcohol intake, water intake, and wheel-running activity during a normal 12 h (h) baseline photoperiod and then during shifting lighting schedules (Experiment 1) or a shortened circadian day (Experiment 2). Results: In Experiment 1, altered lighting produced a persistent increase in adolescent alcohol intake and in binge-like drinking (drinking at least 5 licks per minute, with no more than a 1 min break in drinking) in adulthood, but only a transient increase in total alcohol intake for the first week after alcohol was reintroduced in adulthood. In Experiment 2, the circadian shift produced a significant increase in alcohol intake in both adolescence and adulthood. Molecular analysis demonstrated changes in plasma corticosterone and neuronal markers of stress and addiction at the conclusion of these experiments in the CD and alcohol-exposed groups. Conclusions: Thus, we conclude that circadian stress during adolescence is sufficient to produce a long-lasting susceptibility to alcohol use.

The mysterious death of the beer drinking champ: potential role for hyperacute water loading and acute hyponatremia.

ABSTRACTHyponatremia is acute when present for <48 h. Most cases of acute hyponatremia involve both excess free water intake and an at least partial urinary free water excretion defect. By contrast, hyperacute water intoxication may result from a large excess electrolyte-free water intake in such a short time that properly working urinary free water excretion mechanisms cannot cope. A hyperacute decrease in serum sodium may lead to death before medical intervention takes place. Well-documented cases have been published in the military medicine literature. In addition, news reports suggest the existence of cases of voluntary ingestion of excess free water by non-psychiatric individuals usually during ‘dare’ activities. Education of the public is required to prevent harm from these high-risk activities. Adequate training of emergency medical units may prevent lethal outcomes. Spanish media reported the case of a male who died following his triumph in a 20-min beer drinking contest. ‘From a heart attack. Man dies after drinking six litres of beer in a contest’ ran the news. We now review the physiology underlying hyperacute water intoxication and discuss the potential contribution of hyperacute water loading and acute hyponatremia to the demise of this patient.

The Quality of Drinking Water for Cattle; It’s A Pity Cows aren’t Capable to Complain Verbally

The necessity of water for support of life is largely unquestioned. Of all the nutrients indispensable for life, water is second only to oxygen in importance. However, this commonplace fact is often not well appreciated. From a nutritional point of view, water is the most critical nutrient for dairy cattle, and is required for numerous important physiological functions. As a whole, the water content of the animal body ranges from 55 to 67 % of body weight. Water is the main component of milk, saliva, and waste products, such as urine and faeces [1]. Water is further lost from the lungs during breathing or panting, by evaporation from the skin, and sweating. Hence, dairy cattle have a large daily requirement for water, most of it being obtained from free water intake. Because dairy cattle suffer more quickly from an inadequate water intake than from a deficiency of any other nutrient, clean, fresh drinking water should be available at all times.

MO172HYPONATREMIA IN PATIENTS WITH COVID19

BackgroundAmong laboratory abnormalities described in the context of SARS-COV-2 infection, hyponatremia seem to be the most common. The mechanism of this sodium disbalance is not well known.AimsCharacterize the incidence, etiology and prognostic value of sodium disbalance in patients with COVID19.MethodObservational pilot study with 37 patients admitted to Hospital Ramon y Cajal in Madrid, Spain, between March and April 2020, with a confirmed diagnosis of COVID19. Patients were followed until discharge or death. Clinical and laboratory data were collected at admission and before the clinical outcome. Variables were analyzed comparing hyponatremic vs eunatremic patients.ResultsDistribution of patients according to their serum sodium was as follows: 16 patients with hyponatremia (44%), 19 with normal serum sodium (51%) and 2 with hypernatremia (5%). The average sodium level in hyponatremic patients was 130 ±3.2 mmol/l, median urine sodium was 36 ±3.2 mmol/l (only 6 urine sample available). Hyponatremia was associated with dyspnea at admission and with higher levels of LDH, neutrophil cells account and C reactive protein. However, no worse prognostic was associated with lower serum sodium. All patients recover sodium levels at discharge treated with salt supplementation and free water intake.Conclusionmild hyponatremia is a common electrolyte disorder associated with COVID19. Sing as low urine sodium and recover with water and salt ingestion, point toward hydrosaline dehydration instead of SIADH as most common origin of hyponatremia.

Urea Use for SIADH: A Case Report and Review of the Literature

Introduction: Hyponatremia is the most frequent electrolyte abnormality among hospitalized patients associated with increased morbidity and mortality. There is a demanding need for affordable and well-tolerated therapies, and urea is a compelling alternative for the syndrome of inappropriate diuretic hormone (SIADH). Urea increases renal water excretion due to osmotic diuresis and reduce urinary sodium leading to an increase in serum sodium. This case illustrates the effect and safe use of urea in a hospitalized patient with SIADH. Clinical Case: An 80-year-old male with history of recurrent anterior chest wall chondrosarcoma despite 3 chest wall resections presented to the hospital for a 4th anterior chest wall resection with reconstruction. Physical examination was notable for euvolemia with no neurologic deficits. Pre-operative labs were significant for a plasma sodium (PNa) 118 mmol/L, potassium 4 mmol/L, BUN 9 mg/dL, Cr 0.72 mg/dL, TSH 2.9 mIU/L, cortisol 21.3 mcg/dL, serum osmolality 267 mOsm/kg, urine osmolality 423 mOsm/kg, and urine sodium 115 mmol/L. Underlying SIADH was initially treated with water restriction of 800 mL/24 h. Previously, he was given a trial of salt tabs, which he did not tolerate due to nausea and emesis. Due to profound hyponatremia, he was started on 2% hypertonic saline. Once PNa levels reached 130 mmol/L, 2% saline was discontinued. Repeated PNa showed a decrease to 128mmol/L. Tolvaptan was not initiated due to lack of insurance coverage and hepatotoxicity, and demeclocycline was not considered due to his known allergy. He was ultimately started on urea powder at 15 g/day and tittered to 30 g/day. In one week PNa improved to 135 mmol/L and remained stable until discharge. Clinical Lessons: The cornerstone of therapy for SIADH relies on reducing free water intake but this is not always feasible or sufficient. Winzer et al. [1] showed that fluid restriction is effective in only 59% of the patient with SIADH. As a result, pharmacology therapy is often needed. European guidelines, as compared to American guidelines, recommend the use of urea instead of vaptans therapy as second-line treatment. The above is based on different studies [2] that have shown that urea has similar efficacy, is more cost-effective, and safer since it does not cause liver toxicity like vaptans. Given this response, it appears that urea should be considered as a second-line therapy to fluid restriction given its tolerability and cost-effectiveness when compared to its alternatives.

Effects of short-term exposure to drinking water contaminated with manure on water and feed intake, production and lying behaviour in dairy cattle

This study aimed to assess the effects of water quality (contamination with manure) on water and feed intake and subsuquent milk production, and lying behaviour in dairy cattle. Fifteen lactating Holstein-Friesian cows were provided one of three water treatments in a cross-over design; clean (tap) water, or water contaminated with either 0.5 mg or 1 mg fresh manure/g water. Cows were managed individually in indoor pens and milk production, feed and water intake (free and via feed) and lying behaviour were recorded daily. Live weight was recorded before and after each treatment exposure. Cows were in their pens for 5 days with clean water (baseline) before given one of the three water treatments for 4 consecutive days. Between each baseline/treatment period the cows were managed as one group on pasture for 5 days with clean water to minimize any carry-over effects. This was repeated until all cows had undergone all treatments. Data were analysed using analysis of variance of the 4-day treatment averages and repeated measures analysis of variance to examine day trends within treatment phases. There was an overall treatment effect on free water intake (P < 0.001, SED: 2.34); cows drank more of the clean water (78.0 L/day, range: 49.2–118.0 L) compared to when it was contaminated with 0.5 mg (68.4 L/day, range: 53.5–82.8 L) or 1 mg manure/g water (67.0 L/day, range: 50.6–86.8 L). The water intake of the two contaminated water treatments increased over the 4 days to be the same as the clean water treatment by day 4 (treatment * day interaction, P = 0.002). The cows obtained considerable amount of water from their feed (on average 48 L/day), however, there was no treatment effect on this water intake (P = 0.511). There was no treatment effect on feed intake, live weight or lying behaviour (P ≥ 0.064). Our results show that cows are sensitive to manure contamination of their drinking water. Cows consumed less contaminated water for the first three days of exposure, however, this was not evident on day four, and the reasons for this are unclear. Water quality did not influence feed intake, production or lying behaviour, however, this could be due to the relatively low levels of contamination used, and/or the high water intake from the feed (cut pasture) may have contributed to meeting metabolic requirements to maintain milk production.

Evaluation of Desmopressin in Critically Ill Patients with Hyponatremia Requiring 3% Hypertonic Saline

BackgroundDesmopressin (DDAVP) is often used for hyponatremia management but has been associated with increases in hospital length of stay and duration of hypertonic saline use. The purpose of this study was to evaluate hyponatremia management strategies and their effect on sodium correction in critically ill patients requiring 3% hypertonic saline (3HS). MethodsThis retrospective, single-center study included critically ill patients with hyponatremia (serum sodium ≤ 125 mEq/L) receiving 3HS from May 31 2015, to May 31 2019. Patients were divided into those who received 3HS for hyponatremia management (HTS) and those who received proactive or reactive DDAVP in addition to 3HS (D-HTS). Patients in either group could receive rescue DDAVP. The primary outcome was the percentage of patients achieving goal sodium correction of 5–10 mEq/L 24 h after 3HS initiation. ResultsGoal sodium correction was achieved in 52.5% of patients in HTS compared to 65.6% of patients in D-HTS (p = 0.21). Patients in HTS had a shorter duration of 3HS infusion (p = 0.0022) with no difference in ICU length of stay, free water intake, urine output, or serum sodium increases 12 and 24 h after receiving 3HS. Overcorrection during any 24- or 48 h period was not statistically different between groups. ConclusionPatients in HTS and D-HTS had similar rates of achieving goal sodium correction at 24 h. A proactive or reactive DDAVP strategy led to an increase in 3HS duration and total amount with no significant difference in rates of overcorrection. Prospective, randomized studies assessing standardized strategies for hyponatremia management and DDAVP administration are warranted.

A Global Review of Monitoring, Modeling, and Analyses of Water Demand in Dairy Farming

The production of milk must be balanced with the sustainable consumption of water resources to ensure the future sustainability of the global dairy industry. Thus, this review article aimed to collate and summarize the literature in the dairy water-usage domain. While green water use (e.g., rainfall) was found to be largest category of water use on both stall and pasture-based dairy farms, on-farm blue water (i.e., freshwater) may be much more susceptible to local water shortages due to the nature of its localized supply through rivers, lakes, or groundwater aquifers. Research related to freshwater use on dairy farms has focused on monitoring, modeling, and analyzing the parlor water use and free water intake of dairy cows. Parlor water use depends upon factors related to milk precooling, farm size, milking systems, farming systems, and washing practices. Dry matter intake is a prominent variable in explaining free water intake variability; however, due to the unavailability of accurate data, some studies have reported moving away from dry matter intake at the expense of prediction accuracy. Machine-learning algorithms have been shown to improve dairy water-prediction accuracy by 23%, which may allow for coarse model inputs without reducing accuracy. Accurate models of on-farm water use allow for an increased number of dairy farms to be used in water footprinting studies, as the need for physical metering equipment is mitigated.