IV Fluid Management DFM Fellows Summer 2010

Objectives Understand the basics of fluid administration Review basics of various fluid options Be able to calculate maintenance fluid rates based on patient weight Be able to estimate fluid losses Be able to calculate fluid replacement

The Learning Curve The information provided is general information regarding fluid administration. Keep in mind that different clinical situations require you to integrate your clinical knowledge of the body and its physiology to make an educated decision. Always consider the patients age, condition, medications and co morbidities before administering fluids. And as you screw up you will learn!

IV Fluids The role of IV fluid administration is to Provide volume replacement Administer medications, electrolytes, blood products, or diagnostic reagents Maintenance/correction of nutritional status Components of fluid and electrolyte therapy Maintenance Replacement Maintenance: meeting the requirements for fluid and electrolyte intake that balance daily obligatory losses Replacement: providing for ongoing and additional losses that occur during the course of therapy (surgery phases: pre/intra/post operative)

Normal Plasma Electrolyte Composition CATION Concentration mEq/L ANION Sodium 135-145 Chloride 95-105 Potassium 3.5-5.0 Phosphate 2.5-30 Calcium 4.0-5.5 Sulfate 1.0 Magnesium 1.5-2.5 Organic acids 2.0 Osmolarity 285-295 Protein 1.6 What are we maintaining: maintaining electrolyte homeostasis

Commonly Used IV Solutions Osmolarity (mOsm/L) Glucose (gm/L) Na+ (mEq/L) K+ (mEq/L) Cl- (mEq/L) Lactate (mEq/L) Ca++ (mEq/L) 0.9% NS 308 154 ½ NS (.45%NS) 77 LR 274 130 4.0 109 28 3 D5W 278 50 D5 ½ NS 406 D5 has 170kcal/L

Components of Fluid and Electrolyte Therapy Maintenance meeting the requirements for fluid and electrolyte intake that balance daily obligatory losses 2. Replacements (Ongoing Losses) providing for ongoing and additional losses that occur during the course of therapy (surgery phases: pre/intra/post operative)

The Balancing Act OUT (~1-1.6L/day for ave. adult) Urine 12-15mL/kg/day Feces 3mL/kg Insensible losses 10-13mL/kg/day IN Drinking Eating Metabolism 3mL/kg IV Fluids? The Metabolism: oxidation of carbs and fat Water losses from skin and respiratory tract With no unusual stresses or losses and normal renal function intake can be balanced to outputs

Maintenance: Water and Electrolyte Needs Replace Urine and insensible losses (1-2 L/day) Replace sodium and potassium loss Na: need 47-147 mEq/day (1-3mEq/kg/day) K: leak about 20mEq/day Osmolarity (mOsm/L) Glucose (gm/L) Na+ (mEq/L) K+ (mEq/L) Cl- (mEq/L) Lactate (mEq/L) Ca++ (mEq/L) 0.9% NS 308 154 ½ NS (.45%NS) 77

Calculating Maintenance Dosing 4-2-1 rule to calculate hourly rate In one hour, a person needs: 4mL/kg for the first 10kg (0-10) 2mL/kg for the next 10kg (10-20) 1mL/kg for the remaining kg (>20) 100-50-20 rule for daily requirements In one day a person needs: 100 mL/kg for the first 10kg 50 mL/kg for the second 10kg 20 mL/kg for the remaining *Remember to divide by 24 for hourly rate* Peds vs. adults

Maintenance Considerations Maintenance Considerations Fever or high ambient temperatures Water loss increases by 100-150ml/day for every degree above 37C Sweating Consider using a hypotonic solution for fluid replacement (0.45% saline) Humidity Breathing humid air decreases loss while dry air may increase relative losses Sweating: the athelete that weighs in before each practice to assess hydration status

Calculate maintenance fluids for a 75 kg patient who is NPO Example Calculate maintenance fluids for a 75 kg patient who is NPO 4-2-1 Rule 10 x 4 = 40 mL 10 x 2 = 20 mL 55 x 1 = 55 mL Total 115 mL/hr 100-50-20 Rule 10 x 100 = 1000mL 10 x 20 = 200 mL 55 x 20 = 1100 Sub total 2300mL/day Total 96 mL/hr

So you know how to calculate fluid maintenance requirements but what happens if the patient has an initial deficit requiring rehydration other than maintenance?

She has had vomiting and has diarrhea x 3days Think About It A 50 kg patient comes into the ED with gastroenteritis She has had vomiting and has diarrhea x 3days What are you concerned about? Dehydration Electrolyte imbalance Decrease in blood pressure What do you want to do? Administer medication for nausea Normalize Electrolytes Expand her intravascular volume Maintain normal fluid homeostasis (maintenance) Replace lost fluid (resuscitation) Account for ongoing losses if present (replacement)

Clinical Signs of Dehydration Feature Mild dehydration (<5%) Moderate dehydration (5%-10%) Severe dehydration (>10%) Heart Rate Normal Slight increase Rapid, weak Systolic BP Normal/ orthostatic Hypotension Mucous Mb Slightly dry Very dry Parched Urine Output Decreased Olguria < 500ml/day Anuria < 50ml/day Oliguria: < 30ml/hr Anuria: 0.5ml/kg/hr

Clinical Signs of Dehydration Clinical Signs of Dehydration This is an objective finding This is a rough estimate of fluid loss Clinical signs may not be evident in adults Adults are able to compensate better than children Calculation Fluid Deficits(L) = weight (kg) x % dehydration Example: Our 50 kg patient with 5% dehydration: 50kg x 5%= 2.5L deficit

Estimate Deficit by Weight Estimate Deficit by Weight Example: Suppose our gastroenteritis patient reports a 5lb weight loss with illness Fluid and Weight 1 L of fluid = 1 kg of weight 1kg= 2.2 lbs Use weight change to determine fluid loss/gain Calculate his fluid deficit 5lb = 2.3kg = = 2.3L fluid deficit

Fluid Deficits After deficit is determined Replace half in 8 hours Our pt has a 2.3L deficit by weight Replace half in 8 hours 1,150mL/8hrs =143mL/hr for the first 8 hrs Replace other half in the next 16 hours 1150mL/16hrs =72mL/hr for the next 16hrs

Total Flow Rate for Maintenance Total Flow Rate for Maintenance Add maintenance to deficit and you’ll have a flow rate Our 50kg patient with gastroenteritis has had a 5lb (2.3kg) weight loss Deficit 1,150mL/8hrs=143mL/hr for the first 8 hrs 1150mL/16hrs=72mL/hr for the next 16hrs Maintenance 4mL/kg x 10kg = 40mL (0-10) plus 2mL/kg x 10kg = 20mL (10-20) 1cc/kg x 30kg = 30mL (20-50) TOTAL maintenance= 90mL/hr

Total Flow Rate For the first 8 hrs For the next 16 hours 90mL/hr + 143mL/hr = 233mL/hr For the next 16 hours 90mL/hr + 72mL/hr = 162mL/hr

Try it! A 176lb athlete presents to the ER after collapsing during football practice. He weighed 184lbs at the beginning of practice. Write an order for IV fluids to correct for deficit and maintenance for the next 24 hours Note: Use patients current weight to determine maintenance

Answer Deficit Maintenance 184 - 176= 8lb = 3.6kg =3.6L = 3,600mL loss Answer Deficit 184 - 176= 8lb = 3.6kg =3.6L = 3,600mL loss 1,800mL/ 8 = 225ml/hr 225 + 120= 345 mL/ hr for the 1st 8 hrs 1,800/16 = 112.5mL/hr 112.5 + 120 = 232.5 mL/ hr for the next 16 hrs Maintenance 176lb = 80kg 40mL (0-10) plus 20mL (10-20) 60mL (20-80) Total= 120mL/hr