Sodium correction formula

Hyponatremia is a common electrolyte disturbance frequently requiring fluid administration for correction to physiologic levels. Rapid correction can be dangerous for patients, leading to cerebral edema and osmotic demyelination among other complications. 1 Determining a safe rate of fluid administration to prevent these issues relies on patient and fluid variables. The majority of cases of osmotic demyelination were originally thought to have taken place with daily sodium correction of greater than 12 mmol/L/day (0.5 mmol/L/hr); however, many experts advocate for a more conservative approach to correction, targeting 4-6 mmol/L/day with a maximum of 8 mmol/L/day. 2 Formula for Sodium Correction • Fluid rate (mL / hour) = [(1000) * (rate of sodium correction in mmol / L / hr)] / (change in serum sodium) • Change in serum sodium = (preferred fluid selected sodium concentration - serum sodium concentration) / (total body water + 1) • Total body water = (weight in kg) * (% body water), whereby % of body water is 0.6 in children and adult males, 0.5 in adult females and elderly males, and 0.45 in elderly females).

AMA Citation Hyponatremia. In: Gomella T, Cunningham M, Eyal FG, Tuttle DJ. Gomella T, & Cunningham M, & Eyal F.G., & Tuttle D.J.(Eds.), Eds. Tricia Lacy Gomella, et al.eds. Neonatology: Management, Procedures, On-Call Problems, Diseases, and Drugs, 7e. McGraw Hill; 2013. Accessed June 15, 2023. https://accesspediatrics.mhmedical.com/content.aspx?bookid=1303§ionid=79662284 APA Citation Hyponatremia. Gomella T, Cunningham M, Eyal FG, Tuttle DJ. Gomella T, & Cunningham M, & Eyal F.G., & Tuttle D.J.(Eds.), Eds. Tricia Lacy Gomella, et al. (2013). Neonatology: Management, Procedures, On-Call Problems, Diseases, and Drugs, 7e. McGraw Hill. https://accesspediatrics.mhmedical.com/content.aspx?bookid=1303§ionid=79662284 MLA Citation "Hyponatremia." Neonatology: Management, Procedures, On-Call Problems, Diseases, and Drugs, 7e Gomella T, Cunningham M, Eyal FG, Tuttle DJ. Gomella T, & Cunningham M, & Eyal F.G., & Tuttle D.J.(Eds.), Eds. Tricia Lacy Gomella, et al. McGraw Hill, 2013, https://accesspediatrics.mhmedical.com/content.aspx?bookid=1303§ionid=79662284. An infant has a serum sodium of 127 mEq/L, below the normal accepted value of 135 mEq/L. The incidence of hyponatremia is greater than hypernatremia in premature infants. Evidence now shows it is a serious condition in very preterm infants (<33 weeks' gestation), who have large variations of the serum sodium concentration, as they are at risk for poor neuromotor outcome at 2 years. Preterm infants with an increase...

Definition Hyponatremia is defined as a serum [Na+] 48 hours since development of hyponatremia. • Note: hyponatremia should be considered chronic whenever the duration is unknown. • Mild: serum [Na+] 130-134 mmol/L. • Moderate: serum [Na+] 120-129 mmol/L. • Severe: serum [Na+] urine osm, then ADH is low (kidneys are appropriately responding by maximizing water excretion, i.e. maximally dilute urine). The problem is excess water intake or inadequate solute intake. A urine osm 100. • Urine sodium can help you determine RAAS activation, which can narrow your differential in cases where volume status is not clear. A low urine sodium suggests RAAS activation, as seen in hyper- or hypovolemia; a high urine sodium may suggest SIADH. • Hypervolemic: ADH is released in response to low effective arterial blood volume (EABV) due to third spacing or poor forward flow. • Ddx: CHF, nephrotic syndrome, liver failure. • Urine Na will be low, since the RAAS system is also activated in response to low EABV. • Hypovolemic: ADH is being released in response to low EABV due to fluid loss. • Extrarenal losses, like GI loss: urine Na will be low, since aldosterone will also be on. • Renal salt wasting: urine Na will be high. Causes include salt-wasting nephropathy, adrenal insufficiency, cisplatin, and thiazide diuretic use. • Euvolemic: • Hypothyroidism: check TSH. • Glucocorticoid deficiency: check AM cortisol. • SIADH: inappropriate release of ADH independent of EABV/osmolality or release of...

diagnosis & symptoms • Hyponatremia is a lab diagnosis. • Consider repeating the lab before initiating therapy, especially if it doesn't match the clinical scenario or if other electrolytes are deranged. An aberrantly low sodium may result from drawing electrolytes upstream from a hypotonic infusion. symptoms • Severe: • Seizure. • Delirium, coma, herniation. • Neurogenic pulmonary edema (figure below). • Non-severe: • Nausea, vomiting. • Headache. • Mild confusion. • Dizziness, gait instability. • Tremor, multifocal myoclonus. • Hyperreflexia, muscle cramps. causes pseudohyponatremia (serum osmolality is not actually low) • Severe hyperglycemia. • Triglyceride level >1,500 mg/dL. • High protein level (multiple myeloma, IVIG). • Exogenous osmoles: • Contrast dye. • Mannitol administration. • Maltose (from IVIG). • Sorbitol/glycine (used for surgical irrigation). severe renal failure • Typically occurs only when GFR solute intake • Psychogenic polydipsia (especially in schizophrenia). • Very rapid water intake (e.g., fraternity hazing, or water loading prior to a drug screen). • Beer potomania (excessive beer intake with reduced solute intake). • Elderly patients who eat a “tea-and-toast” diet, or anorexia (low solute intake). hypovolemic hyponatremia • Non-renal losses • GI loss (vomiting, diarrhea, gastric tube drainage). • Hemorrhage. • Sweating, burns. • Renal losses • Diuretics (esp ecially thiazides). • Post-obstructive diuresis. • Hypoaldosteronism or a drenal insuf...

Hyponatremia and hypernatremia are common findings in the inpatient and outpatient settings. Sodium disorders are associated with an increased risk of morbidity and mortality. Plasma osmolality plays a critical role in the pathophysiology and treatment of sodium disorders. Hyponatremia and hypernatremia are classified based on volume status (hypovolemia, euvolemia, and hypervolemia). Sodium disorders are diagnosed by findings from the history, physical examination, laboratory studies, and evaluation of volume status. Treatment is based on symptoms and underlying causes. In general, hyponatremia is treated with fluid restriction (in the setting of euvolemia), isotonic saline (in hypovolemia), and diuresis (in hypervolemia). A combination of these therapies may be needed based on the presentation. Hypertonic saline is used to treat severe symptomatic hyponatremia. Medications such as vaptans may have a role in the treatment of euvolemic and hypervolemic hyponatremia. The treatment of hypernatremia involves correcting the underlying cause and correcting the free water deficit. Clinical recommendation Evidence rating References Comments In patients with severe symptomatic hyponatremia, the rate of sodium correction should be 6 to 12 mEq per L in the first 24 hours and 18 mEq per L or less in 48 hours. C Consensus guidelines based on systematic reviews A bolus of 100 to 150 mL of hypertonic 3% saline can be given to correct severe hyponatremia. C Consensus guidelines based on s...