![]() ![]() In anesthetic practice, this formula has been further simplified, with the hourly requirement referred to as the “4-2-1 rule” (4 mL/kg/hr for the first 10 kg of weight, 2 mL/kg/hr for the next 10 kg, and 1 mL/kg/hr for each kilogram thereafter. Viewed in this manner, the authors concluded that 100 mL/kg/day for weights to 10 kg, an additional 50 mL/kg/day for each kilogram from 11 to 20 kg, and 20 mL/kg/day more for each kilogram beyond 20 kg. This curve could be seen comprising of three linear sections which coincided approximately with the following weight sections: 0 to 10 kg, 10 to 20 kg, and 20 to 70 kg. Based on their data and assumptions, Holliday and Segar constructed a curve plotting Energy Caloric Requirements versus Weight. ![]() The relationship between Weight and Energy Expenditure was found to be NON-LINEAR. In other words “the average needs for water, expressed in milliliters, equals energy expenditure in calories (under normal resting conditions, 1 ml of water is required to metabolize 1 kcal)". ![]() In a study published in 1957, in the Journal Pediatrics, Malcolm Holliday and William Segar developed a simple scheme which could be easily remembered to calculate the maintenance water needs in hospitalized patients.Īssimilating the known physiology at the time, they observed that “there was a DIRECT LINEAR relationship between Physiologic Water Needs (insensible losses + urinary losses) and Energy Metabolism". Note: K concentration in IV fluids of up to 40 mEq/L is used for correction of hypokalemia.One of the primary objectives of maintenance parenteral fluid therapy is to provide water to meet physiologic losses (insensible loss + urine loss). In children who have a condition that might predispose to renal failure, such as dehydration, K is not added to intravenous fluids until the presence of renal function has been established. This was estimated by Holliday and Segar to again reflect the composition of human and cow milk and has remained the same since then. Potassium either comes pre-added or can be manually added to any intravenous solution at a concentration of 2 mEq/100 ml or 20 mEq/L to provide the appropriate amount of K for maintenance. The maintenance K requirement is estimated at 2 mEq/100 ml of fluid or 20 mEq/L. Combine this with hypotonic IV fluids, and you have a perfect formula for hyponatremia. The more ADH, the more water is reabsorbed from the collecting duct of the kidneys. All of these things cause an increase in ADH release. They are vomiting, or have respiratory illness, or require surgery, or have fever. We know that kids in the hospital are stressed. The maintenance fluids calculator (MIVF calculator) uses the Holliday-Segar method and the 4-2-1 rule to determine the daily and hourly need for fluids in. Reference: AAP Guidelines on Maintenance IV Fluids in Hospitalized Children Based on current research, it is determined that giving hypotonic solutions as maintenance IV fluids is associated with severe morbidity and even mortality due to hyponatremia. Note that all of these are considered hypotonic to plasma. (154 mEq/L divided by 5 is roughly 30 mEq/L).įor decades, our maintenance IV fluids have ranged anywhere from 1/5NS to 1/3NS to Ѕ NS. When to Use Weight lbs Volume to be calculated mL Period of time hours Result: Please fill out required fields. ![]() So if we wanted to add 30mEq/L of Na, we would need 1/5NS. Calculates fluid status in volume per weight & volume per weight per time, for pediatrics. When we speak about adding sodium to IV fluids, we talk about it in terms of normal saline. For an adult, this will provide about 75 mEq of Na/day, equivalent to approximately 4.5 G of salt. So, Na is added to maintenance fluids at a concentration of 3 mEq/100ml or 30 mEq/L. Holliday and Segar decided on this number by looking at the sodium content of human and cows' milk. Salt intake => increase in plasma Na and osmolality => increased thirst and increased ADH secretion => chug-a-lug => water intake and water retention, plasma dilution => plasma Na and osmolality decline almost to baseline at the expense of expanded plasma volume (I cannot take off my rings socks leave deep marks on shin!) => the kidney stops making renin => no renin, so no angiotensin and no aldosterone => Na re absorption declines in the collecting duct => urinary Na excretion increases until all the salt from the pizza has been excreted => plasma osmolality falls as Na is excreted => ADH shuts off => water is excreted until plasma volume has declined to baseline.īased on recommendations made by Holliday and Segar, the daily sodium requirement was estimated at 3 mEq/100 ml of water water requirement. ![]()
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