Lecture 8. Fluid and Electrolyte Therapy.pptx

Veterinary pharmacology

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2. 40-50% of body wt 11-15% 5% Physiology of Body Water Balance Body water is divided to 3 compartments waktole 1/20/2023

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4. Body Water Disturbances Evaluated as total volume and individual compartments Dehydration: Fluid volume is low in all three compartments Hypovolemia: Low vascular fluid Total body water overload TBW > 60% Not specify abnormalities in individual compartments Distribution of water must be known before appropriate action can be taken Edema Collection of fluid in interstitial space due to low oncotic pressure in the vascular compartment. E.g low albumin levels 1/20/2023 waktole

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6. Estimating the percentage dehydration based upon physical examination findings Estimated % Dehydration Physical Examination Findings <5 History of fluid loss but no findings on physical examination 5 Dry oral mucous membranes but no panting or pathological tachycardia 7 Mild to moderate decreased skin turgor, dry oral mucous membranes, slight tachycardia, and normal pulse pressure. 10 Moderate to marked degree of decreased skin turgor , dry oral mucous membranes, tachycardia, and decreased pulse pressure. 12 Marked loss of skin turgor , dry oral mucous membranes, and significant signs of shock . waktole 1/20/2023

7. Phases of fluid therapy Three phases Emergency phase – Returning the patient's status to normal ( deficit volume ) Replacement phase- Replacing normal ongoing losses ( maintenance volume ) Maintenance phase- Replacing continuing abnormal losses ( continuing losses volume ) waktole 1/20/2023

8. Phases of fluid therapy …. Total Deficit Replacement Volume = Deficit Volume PLUS Maintenance Volume Deficit replacement volume (ml) = % dehydration x body weight (kg) x1000 b x 0.80 where, b = 1000 ml = 1 kilogram E.g. A 22-lb (10 kg) dog is assessed to be 7% dehydrated. What volume of fluid deficit should be given during the first 24 hours? Ans. DRFV= (ml) = 0.07 x 10 x 1000 x 0.80 = 560ml waktole 1/20/2023

9. Maintenance fluid volume Maintenance fluid volume MFV= (30 X BW Kg ) + 70 A 22-lb (10 kg) dog is assessed to be 7% dehydrated and has been vomiting. How much fluid should be given during the next 24 hours? Volume (ml of fluid required) = deficit volume + maintenance volume = [0.07 x 10 kg x 1000 x 0.80] + [(10 x 30) + 70] = [560] + [370] = 930 ml waktole 1/20/2023

10. Fluid and Electrolyte Replacement Oral administration Parenteral administration The main objectives of fluid therapy the correction of extracellular fluid (ECF) volume, plasma pH, and plasma concentrations of K+ and Na+; and the restoration of cellular K+. Any severely dehydrated, shocked, or collapsed animal almost certainly requires parenteral, preferably intravenous, fluid therapy before oral rehydration therapy. waktole 1/20/2023

11. Oral administration Diarrhea occurs when net enteric uptake of Na and H 2 O is impeded to a degree that overwhelms the substantial compensatory capacity of the colon. The most damaging effects are: to contract ECF volume, particularly plasma volume, and metabolic acidosis . waktole 1/20/2023

12. Parenteral administration Subcutaneous In mild dehydration Isotonic fluids of no more than 5 to 10 ml/lb should be given at each injection site. The rate of subcutaneous fluid flow usually is governed by patient comfort Intraperitoneal route quick, easy, and the fluids will generally be reabsorbed thus increasing the circulating volume. there is the potential of bacterial peritonitis IV fluid administration indicated in dogs and cats with 7% or greater dehydration. Sites : Peripheral veins Jugular veins Intraosseous waktole 1/20/2023

13. Parenteral Fluids Infusion: Administration of > 100 ml fluid by parenteral route Tonicity Osmotic pressure of fluid in relation to plasma Parenteral fluids can be Isotonic : osmotic pressure of the fluid = OP of the plasma Hypertonic : OP > OP of plasma by > 50. Hypotonic: OP < OP of plasma at least by 50 waktole 1/20/2023

14. Types of Replacement Fluids 1-Crytalloid contain electrolyte NS and lactate ringer most commonly Isotonic with ECF 2-Colloid contain plasma protein or other colloidal molecule Three types a - plasma protein fraction PPF 85% albumin & 15% globulin available as 5% solution b- albumin available as 5% and 25% c- hetastarch available as 6% solution has same homodynamic effect as albumin not extracted from pooled human plasma Less expensive than PPF or albumin contain 130-160 mmol of Na & Cl/L 1/20/2023 waktole

15. Conditions Disturbances Fluids Suggestive Additives Anorexia 1. Short term 2. Long term(calorie & protein depleted 1. 0.18NaCl+5% glucose 2. Parenteral Nutrition KCl (20-30mmol/L) Vomiting (Bile stained) Loss of H 2 O, H+, K+, Na+, Cl- [metabolic alkalosis] Loss of H 2 O, H+, HCO 3- ,K+, Na+, Cl-[metabolic acidosis] 0.9%NaCl or Ringer lactate Hartman's solution KCl (20-30mmol/L) if therapy > 3 days Diarrhea Loss of H 2 O, H+, HCO 3- , Na+, Cl-, K+(if long term), [metabolic acidosis] Hartman's solution (lactated Ringer’s) - KCl (20-30mmol/L)for prolonged therapy -HCO3(1-3mmol/kg) for severe & prolonged therapy Hemorrhage Blood loss, hypovolemic shock Plasma expander or H artman’s solution, whole blood for low PCV Burns Loss of plasma & ECF: hypovolemic shock Plasma expander + H artman’s solution HCO3(1-3mmol/kg) Parenteral fluid therapy for various disorders waktole 1/20/2023