Mosm

Learning Outcomes • Explain osmolarity and the way in which it is measured Transport of Electrolytes Electrolytes, such as sodium chloride, ionize in water, meaning that they dissociate into their component ions. In water, sodium chloride (NaCl), dissociates into the sodium ion (Na +) and the chloride ion (Cl −). The most important ions, whose concentrations are very closely regulated in body fluids, are the cations sodium (Na +), potassium (K +), calcium (Ca +2), magnesium (Mg +2), and the anions chloride (Cl −), carbonate (CO 3 –2), bicarbonate (HCO 3 –), and phosphate(PO 3 –). Electrolytes are lost from the body during urination and perspiration. For this reason, athletes are encouraged to replace electrolytes and fluids during periods of increased activity and perspiration. Osmotic pressure is influenced by the concentration of solutes in a solution. It is directly proportional to the number of solute atoms or molecules and not dependent on the size of the solute molecules. Because electrolytes dissociate into their component ions, they, in essence, add more solute particles into the solution and have a greater effect on osmotic pressure, per mass than compounds that do not dissociate in water, such as glucose. Water can pass through membranes by passive diffusion. If electrolyte ions could passively diffuse across membranes, it would be impossible to maintain specific concentrations of ions in each fluid compartment therefore they require special mechanisms to cross t...

How many calories is my patient getting? This calculator is intended to provide clinicians with a 'snapshot' of a patient's existing enteral and parenteral nutrition status. Rather than providing a recommended nutritional regimen, this evaluation and analysis tool will summarize a patient's nutritional intake as it relates to total calories, macronutrients, fluid, and weight-based nutritional metrics (eg, protein per kg, kcal per kg, etc.). In its simplist form, it answers the question of "How many calories is my patient getting"? If you are interested in calculating a new regimen for a patient, please see the Nutritional weight calculation In obese patients, this calculator uses a correction adjustment of 25% (see equation below); however, it is important to note that a higher correction coefficient (ie, 50%) may be appropriate for patients on chronic enteral or parenteral therapy when the goal is to provide full calories. 2 $$\\ Nutritional\;weight = IdealBW + 0.25*(ActualBW - IdealBW)$$ Macronutrient Caloric Density The following macronutrient caloric density are used for calculations: Lipid Dextrose Protein 9 kcal/g 3.4 kcal/g 4 kcal/g Osmolarity calculation An osmolarity calculation may be useful for determining whether a patient's TPN requires a central line (>900 mOsm/L) or if it may be infused via a peripheral line (eg, "peripheral parenteral nutrition", or PPN). 3 Note that the osmolarity calculation included in this calculator does not account for electrolytes, w...

G uidelines for how to diagnose and characterize ocular surface disease have been available for years. Yet a 2019 survey by the American Society of Cataract and Refractive Surgery found that many surgeons don’t know the guidelines, even though they realize the disease can affect surgical outcomes. 1 “I think most of us want to diagnose OSD accurately but, frankly, the disease is more complex than a lot of us realize,” says Kenneth Beckman, MD, a clinical assistant professor of ophthalmology at Ohio State University. Performing cataract surgery on patients with unrecognized OSD can lead to refractive errors, OSD exacerbations and dissatisfaction with surgical outcomes. 1,2 Significant lid destruction 3 can occur in nonsurgical patients, and the disease can destroy more than half of the meibomian glands of otherwise healthy patients in their 20s. Figure 1. Expressing meibum in patients with meibomian gland dysfunction can help remove bacteria and debris, as well as stimulate the glands. For a video showing Dr. Yeu performing meibomian gland expression, visit OSD patients of all ages can develop photophobia, corneal scarring, intermittent blurred vision, pain, limited ability to perform daily activities, reduced vitality, poor general health and, in many cases, depression. 4,5 Do you screen thoroughly enough to spare patients these problems? Find out how experts do so by balancing diagnostic protocols against the need to respond to unique patient problems. Overview of Disease...

1 Copy link Introduction Midline catheters represent a unique vascular access device (VAD) for patients requiring intravenous (IV) administration of drugs or other infusates. 1,2 After their introduction in the 1950s, hypersensitivity and phlebitis reactions to the manufacturing materials led to a temporary decline in the use of midline catheters through the 1990s; however, a redesign of these products in recent years has led to their renewed adoption. Midline catheters have properties that differ from both those of traditional peripheral IV catheters and central venous catheters (CVCs). Therefore, questions often arise regarding the appropriateness of administering specific drugs via midline catheter. This review provides an overview of midline catheters and a summary of properties that influence the determination of whether a drug is appropriate for administration via midline catheter. Properties of midline catheters Midline catheters differ from other VADs with regard to their insertion and termination sites. 1,3 Midline catheters are inserted peripherally into the antecubital fossa or upper arm via the basilic, cephalic, or brachial vein, and extend from 8 to 20 cm centrally, where the catheter tip terminates at or below the axillary vein. Because this termination site is distal to those of CVCs and peripherally inserted central catheters (PICCs), midline catheters are not considered to dwell in the central circulation. 1 Whereas the central termination site of CVCs an...

Osmolality (Blood) Does this test have other names? Serum osmolality, osmolality serum, plasma osmolality What is this test? This test measures the concentration of dissolved particles (osmolality) in your blood. This test can help diagnose a fluid or electrolyte imbalance, including dehydration. Electrolytes are mineral salts that help move nutrients into your cells and waste products out of your cells. Electrolytes also control your acidity and pH levels. The more diluted your blood and urine are, the lower the concentration of particles. When there is less water in your blood, the concentration of particles is greater. Osmolality increases when you are dehydrated and decreases when you have too much fluid in your blood. Your body has a unique way to control osmolality. When osmolality increases, it triggers your body to make antidiuretic hormone (ADH). It's also called arginine vasopressin (AVP). This hormone tells your kidneys to keep more water inside your blood vessels and your urine becomes more concentrated. When osmolality decreases, your body doesn't make as much ADH. Your blood and urine become more diluted. Why do I need this test? You may need this test if you have seizures or problems with ADH. You may also have this test if you are dehydrated or if your healthcare provider thinks you might have diabetes insipidus (DI). Diabetes insipidus happens when your body makes less ADH. DI can also happen if your kidneys are not responding to ADH, even though you are m...

Osmolarity Osmolarity is defined as the number of ionic species in molarity that has a characteristic range depending on the species examined. From: Biochemical Ecotoxicology, 2014 Related terms: • Biofilm • Blood Plasma • Tissues • Solution and Solubility • Cell Membrane • Osmotic Stress • Cell Wall François Gagné, in Biochemical Ecotoxicology, 2014 2.1.6Osmolarity Osmolarity is defined as the number of ionic species in molarity that has a characteristic range depending on the species examined. It is calculated as the sum of molar ionic species in a media, for example, 150mM NaCl has an osmolarity of 150mM Na ++150mM Cl −=300mOsmol; 50mM CaCl 2 and 5mM NaHCO 3 have an osmolarity of 50mM Ca 2++2×50mM Cl −+5mM Na ++5mM HCO 3 −=160 mOsmol. In vertebrates, the plasma osmolarity values are range from 275 to 325mOsmol. The maintenance of cells, membrane vesicles, or intracellular organelles (microsomes, mitochondria, and nuclei) is dependent on the transmembrane equilibrium of osmotic pressure to prevent hypo-osmotic or hyper-osmotic stress. For example, cell culture media are usually adjusted to 290–320mOsmol to prevent any osmotic stress to cells. If the osmolarity is not known then a value could be determined by measuring the conductivity of cells or tissues homogenized in water if the plasma (or hemolymph) is not available. In freshwater mussels, the hemolymph has an osmolarity of 70–100mOsmol (35–50mM NaCl). The osmolarity of homogenization buffers or cell culture media mu...

Calculating Osmolarity of an IV Admixture Calculating Osmolarity of an IV Admixture Introduction There are any number of ways to calculate the osmolarity of an I.V. admixture, here is one method: • For each component of the admixture, multiply the volume in milliliters of that component times the value of mOsm per ml of the component. • Add the mOsm obtained in step [1] for each of the components in order to determine the total number of milliosmoles in the admixture. • Add together the volumes of each component in order to obtain the total volume of the admixture. • Divide the total number of milliosmoles from step [2] by the total volume from step [3], then multiply by 1,000 to obtain an estimate of the osmolarity of the admixture in units of milliosmoles per liter. Example Calculation DESCRIPTION VOLUME x mOsm/mL = mOsm Sterile Water for Injection 500mL x 0.00 = 0.00 Sodium Bicarbonate 8.4% 50mL x 2.00 = 100.00 Potassium Chloride 2 mEq/ml 10mL x 4.00 = 40.00 Heparin 5,000 units/ml 0.5mL x 0.46 = 0.23 Pyridoxine 100 mg/ml 1mL x 1.11 = 1.11 Thiamine 100mg/ml 1mL x 0.62 = 0.62 Totals [3] 562.50mL [2] 141.96 [Step 4] Osmolarity of Admixture (141.96 / 562.5) x 1,000 = 252 mOsm / L Small Volume Parenterals The following table lists the values of mOsm per ml for common IV admixture components. These values were obtained from the package inserts for each product at the time this table was compiled. Because formulations vary between manufacturers and may change over time, please...