Fluid therapy in animals

Basics of fluid therapy

1. Fluid therapy in animals Dr Vinodh Kumar O.R Senior Scientist ICAR- Indian Veterinary Research Institute Bareilly, Uttar Pradesh

2. Distribution of water in body

3. Composition of IC & EC fluids

4. Three types of fluid disturbances : 1. Changes in volume (e.g., dehydration, blood loss ) 2. Changes in content (e.g., hyperkalemia ) 3. Changes in distribution (e.g., pleural effusion)

5. Fluid therapy Types Replacement therapy: Therapy in which we infuse same type of fluid which is lost from body . Adjunctive Therapy: One type of fluid is given to remove other type of fluid e.g. mannitol 25% is given in case of ascites and edema. Supportive Therapy: Fluid is given to animal just to support him to cure quickly i.e. amino acids, minerals, multivitamins and carbohydrates etc.

6. Different routes of fluid administration

7. Different routes of fluid administration

8. Indications for intravenous fluids Replace extracellular fluid volume losses Maintain fluid and electrolyte balance Correct existing electrolyte or acid-base disorders Provide a source of glucose

9. Reasons for Fluid Therapy Vasoconstriction Pale mucous membranes Prolonged capillary refill time Peripheral temperature < core temperature Reduced urine output Decreased mentation Tachycardia (cats may present with bradycardia) Hypotension (poor pulse quality) Reduced oxygen saturation (low SpO 2 ) Lactate >2 mmol /L Metabolic acidosis/Alkalosis

10. Evaluation and Monitoring Parameters for fluid therapy

11. Dehydration Dehydration or the loss of fluid from the interstitial space in the form of increased fluid loss from vomiting , diarrhea, or polyuria is one of the main cause of water reduction in body . Signs include decreased skin tenting , sunken eyes, depressed mentation , and tacky/dry mucous membranes, CRT 2-3 sec in mild cases and >3 sec in severe cases , Slight depression of eyes into sockets.

12. Determining a patient's degree of dehydration 5 %-6% dehydrated:  Subtle loss of skin elasticity 6%-8% dehydrated:  Definite delay in return of skin to normal position (skin turgor), slight increase in capillary refill time, and eyes may be slightly sunken into orbits 10%-12% dehydrated:  Extremely dry mucous membranes, complete loss of skin turgor, eyes sunken into orbits, dull eyes, possible signs of shock (tachycardia, cool extremities, and rapid and weak pulses), and possible alteration in consciousness 12%-15% dehydrated:  Definite signs of shock; death is imminent if not corrected

13. Assessing for Fluid Therapy The first step in determining whether a patient needs fluid therapy is a full physical examination, including collection of a complete history . Check perfusion of tissues Check for dehydration, and evaluate losses from any of the fluid compartments. Patients that cannot adequately perfuse their tissues require immediate intervention with fluid therapy to restore perfusion and correct shock.

14. IV fluid therapy indicates that the assessment of patients should include Physical examination Observation of vital signs over time Clinical presentation.

15. Diagnosing Dehydration Physical exam Weight loss PCV (HCT) increased Albumin or total protein increased BUN, creatinine Prerenal azotemia

16. Clinical examination of Degree of Dehydration

17. Shock

18. Five ‘ Rs ’ of intravenous fluid administration Resuscitation Routine maintenance Replacement Redistribution Reassessment

19. Resuscitation To ascertain the fluid requirements of patients who are acutely ill, an accurate assessment is needed and should include the ABCDE. Routine maintenance fluids are needed in patients who are at ongoing risk of fluid loss.

20. Replacement Assessment should focus on: Ensuring adequate hydration; Ensuring electrolyte balance; Checking for any potential fluid overload. Alterations in potassium – either hypokalaemia or hyperkalaemia – can affect patients’ cardiac performance causing arrhythmias, heart failure and/or cardiac arrest . If continued fluid loss is suspected, this should be checked and losses monitored.

21. Redistribution Redistribution of fluid can occur in critical illness. Fluid is lost from the circulatory volume and moves into the tissues; this is called ‘third space loss ’. M onitoring of central venous pressure, kidney function tests or high dependency care, may be required.

22. Reassessment Regular reassessment of patients’ fluid therapy needs is essential. Enteral routes reduce the need for IV access and, in doing so, reduce the risks of ongoing IV therapy, such as catheter-related infections

23. Different types of IV fluids

24. Crystalloids Crystalloid solutions are isotonic plasma volume expanders that contain electrolytes. Isotonic fluids can increase the circulatory volume without altering the chemical balance in the vascular spaces. Crystalloid solutions are mainly used to increase the intravascular volume when it is reduced ( haemorrhage , dehydration or loss of fluid during surgery)

25. Colloids Colloids are gelatinous solutions that maintain a high osmotic pressure in the blood . C olloids are too large to pass semi-permeable membranes such as capillary membranes, so colloids stay in the intravascular spaces longer than crystalloids. Examples : albumin , dextran, hetastarch , Haemaccel and Gelofusin

26. Which fluid to administer? Crystalloids and colloids are plasma volume expanders used to increase a depleted circulating volume. Both are suitable in fluid resuscitation, hypovolaemia , trauma, sepsis and burns, and in the pre-, post- and peri -operative period . Colloids carry an increased risk of anaphylaxis, are more expensive.

27. Comparison of crystalloid and colloid solution

28. Rules of IV fluid therapy

29. Rules of IV fluid therapy

30. Clinical characteristic of IV fluids Ringer lactate is the most physiological iv fluid Isotonic saline and DNS have maximum sodium Isotonic saline DNS and ISO-G have maximum chloride Isolyte – E,P,M directly correct acidosis Isolyte -G only iv fluid which directly correct metabolic alkalosis. Isolyte - M,P,G,E and Ringer lactate are usually avoided in renal failure. Isolyte - G and Ringer lactate are avoided in patients with liver failure.

31. Clinical characteristic of IV fluids Isotonic saline and Ringer Lactate do not contain glucose so preferred fluid for diabetic patients . D5,D10 and D20 are only fluids which do not contain Na and Cl. Isolyte -M and P have low Na and Cl . NS , DNS and dextrose containing fluids do not contain potassium and they do not correct metabolic acidosis and alkalosis directly.

32. Characteristics of intravenous fluids

33. IV fluid advantages and disadvantages ication

34. Crystalloid classification Maintenance fluid Replacement fluid Special fluid 5% Dextrose Normal Saline 25% Dextose Dextrose with 0.45% Normal Saline DNS Sodium bi carbonate Ringers lactate Potasium Chloride Isolyte - M, P, G

35. Complications of intravenous fluids

36. Fluid therapy in small animals

37. Principles of Rehydration Correct dehydration, electrolyte, and acid-base abnormalities prior to surgery. Do not attempt to replace chronic fluid losses all at once. Severe dilution of plasma proteins, blood cells and electrolytes may result Aim for 80% rehydration within 24 hours Monitor pulmonary, renal and cardiac function closely

38. Example An adult 18kg cat with 6% dehydration comes into the clinic. It is estimated that the cat vomited 150 ml of fluid overnight • Maintenance fluids can be dosed at 50 ml/kg/day in adults and 110 ml/kg/day in young animals • Calculate maintenance volume 18kg x 50 ml/kg/day = 900ml per day • Rehydration fluid is based on the estimated percent of dehydration % dehydration x weight in kg = deficit in liters

39. Example Calculate replacement for dehydration 6 % = 0.06 0.06 x 18 kg = 1.08 l 1.08 l x 1,000 ml/l = 1080 ml 1080ml x 0.8 (80% of dehydration value replaced in 24 hours) =840 ml to replace on first day • Take estimated volume lost in fluid and add to the other volumes • Final step: Take all values and add together 900ml + 840 ml + 150 ml = 1890ml

40. Indications of fluid overload Serous nasal discharge Increased respiratory rate (Dyspnea ) Crackles or muffled lung sounds on pulmonary auscultation Late stage consequence = pulmonary edema (or pleural effusion in cats) Decreased PCV Increased BP

41. SC fluids injection site in dogs

42. Cats SC fluid site

43. IV in cats

44. IV in dogs

45. Intraosseous catheter placed in the femur