dehydration - 2023-2024 2.pdf

Assessment of dehydration and principles of fluid replacement therapy Dr. Fuad A. M. Ali Unit I - year 2 Problem: Homeostasis A Academic year 2024/2025 Total body water (TBW) = 50–75% of the total body mass TBW is divided into:...

Assessment of dehydration and principles of fluid replacement therapy Dr. Fuad A. M. Ali Unit I - year 2 Problem: Homeostasis A Academic year 2024/2025 Total body water (TBW) = 50–75% of the total body mass TBW is divided into: Intracellular Fluid (ICF) : 2/3 of TBW think deed cells water Extracellular spaces(ECF): 1/3 of TBW plasma (intravascular) fluid in body Interstitial fluid (ISF) ECF ICf interstitial Plasma intravascular  : Sodium ; mostly extracellular green intracellular ; mostly white : Potassium The principal constituents of plasma are: Sodium, chloride, bicarbonate, and protein (primarily albumin). no protein The ISF is similar to plasma but lacks significant amounts of protein yes protein The ICF is rich in potassium, magnesium, Loading… phosphates, sulfates, and protein  FLUID & ELECTROLYTE MANAGEMENT Therapy of fluid and electrolyte disorders is directed toward providing 1. Fluid (water) 2. Electrolytes (Sodium chloride, Potassium) 3. Glucose (we will not discuss this in this unit) Calculate: 1) Maintenance: Daily requirement for next 24 hours daily requirement to maintain homeostasis 2) Deficit: Replacement of prior loss (e.g., vomiting, diarrhea, poor intake etc.) Loading… what has been lost compensating Maintenance: for water + Electrolytes (mainly sodium chloride and potassium) Deficit: for water + Electrolytes (mainly sodium chloride and potassium)  Maintenance Body Weight (kg) mL of Water/kg 1) Water: 1–10 100 mL / kg first ten 11–20 50 mL/ kg second ten Example 1 : > 20 20 mL/ kg third ten 28 kg patient. The maintenance is: Up to a maximum of 2400 mL daily. First 10 kg = 10 X 100 = 1000 ml X 100 = 1000 mi Second 10 kg = 10 X 50 = 500 ml ↓ 50 = 500 mi Third 8 kg = 8 X 20 = 160 ml X 20 = 160 mi Maintenance = 1000 + 500 + 160 = 1660 ml / 24 hours Example: 2 15 kg patient. The maintenance is: First 10 kg X = 10 X 100 = 1000 ml 100 = 1000 Second 5 kg = 5 X 50 = 250 ml X50 = 250 Maintenance = 1000 + 250 = 1250 ml / 24 hours Example: 3 7 kg patient. The maintenance is: First 7 kg = 7 X 100 = 700 ml X 100 = 700 Maintenance = 700 ml / 24 hours 2) Sodium Maintenance = weight x 3 = 3 meq / kg / 24 hours mill i equivalent 7 kilo child : 7x3 = 21 15 Kilo teenager : 15 X3 = 45  Deficit 1) Water deficit: Water deficit is what the patient already lost because of or due to: decrease Input (elderly) 1. Decrease intake orally increase output (child) 2. Increase loss: due to GIT: diarrhea and vomiting diabetes Kidneys: increase urine output Skin: insensible water loss, burn Lung: hyperventilation This will lead to dehydration Clinical symptoms and signs of Dehydration: Vital signs: by examining less fluid in your body, which means there’s less blood flowing fast heart heart through your veins. To keep everything working properly, your heart Increase pulse rate: Tachycardia & has to pump faster to move the reduced blood volume around your body. This makes your heart rate go up. volume of blood vessel is small Low BP : hypotension Loading… Clinical Signs of dehydration Depressed anterior fontanel (children below 1 ½ years) Sunken eye Absent tears Dry mucus membrane Decrease skin turgor decreased Skin turgor , if you Pinch the skin it will go down Slowly Press hall , become white to Delay capillary refill pink Decrease urine output Weight loss Sunken anterior fontanelle Sunken eyes Sunken eyes Dry mucous membrane Decrease skin turgor (inelastic skin) Decrease skin turgor (inelastic skin) Delay capillary refill (more than 3 seconds)  Laboratory indicators of dehydration: moderate lost one kI10. from 10 to a = 10 % Answer: He lost 1 kg which is 10 % of his weight (10 kg). So, he is moderately dehydrated. Mild dehydration: The patient will have only thirst, dry mucous membrane and slight decrease urine output. Moderate dehydration: The patient will have dry mucous membrane, decrease urine output (oliguria), slight increase in time of capillary refill, decrease skin turgor and slight increase pulse rate. Sever dehydration: The patient will be in hypovolemic shock. He will have hypotension, tachycardia, delay capillary refill and anuria (no urine output) in addition to all above findings Calculating the replacement of water deficit: Mild (3 - 5 %) = weight X 3 - 50 ml Moderate (6 - 10 %) = weight X 60 - 100 ml Sever (9 - 15 %) = weight X 90 - 150 ml 1) Sodium deficit: The normal sodium level is 137 – 148 mEq/L Types of Dehydration: normal 1- Isonatremic dehydration: If serum sodium level 137 – 148 mEq/L less than 137 2- Hyponatremic dehydration: If serum sodium level < 137 mEq/L more than 148 3- Hypernatremic dehydration: If serum sodium level > 148 mEq/L Hyponatremic dehydration (serum sodium less than 137 mEq/L) Sodium deficit = (desired sodium – observed sodium) X bodyweight (kg) X 0.6 Example: Sodium level 127 mmol/L (Normal is 137 – 148) in patient weight 20 kg Sodium deficit = (137 – 127) X 20 X 0.6 = 120 mmol / 24 hours · total body fluid 60% Treatment of Dehydration If the dehydration is Mild or moderate with no vomiting: if mild moderate we can give it orally , start oral rehydration solution (ORS) Composition of Oral Rehydration no need to remember numbers Solution Reduced Osmolarity ORS Standard ORS mmol/L 75 111 Glucose 75 90 Sodium 65 80 Chloride 10 Loading… 20 Potassium 10 10 Citrate 245 311 Osmolarity Studies showed that the new reduced ORS is better than the standard ORS. It reduces the need for I.V. therapy by about 30% It reduces the diarrhea by about 20% It reduces the vomiting by about 30% If the dehydration is moderate with vomiting or sever dehydration: start Intravenous fluid (IVF) Summary  know these Body Weight (kg) mL of Water/kg 1) Water Maintenance 1–10 100 / kg 2) Sodium Maintenance 11–20 50 mL/kg > 20 20 mL/kg = 3 meq / kg / 24 hours 3) Water deficit: Mild (3-5 %) = weight X 30 - 50 ml Moderate (6-10 %) = weight X 60 - 100 ml Sever (9-15 %) = weight X 90 - 150 ml 4) Sodium deficit = (desired sodium – observed sodium) X bodyweight (kg) X 0.6