perioperative fluid therapy anesthesia.pptx

peiroperative fluid theray

1. Perioperative fluid therapy Department of Anesthesiology 1

2. Objectives Introduction Physiology Surgical fluid requirement Fluid Replacement Assessment and Monitoring Crystalloid & Colloid Department of Anesthesiology 2

3. Why do we need Fluid? Avoid dehydration Maintain adequate effective circulating volume Prevent inadequate tissue perfusion Maintain distribution of electrolytes Department of Anesthesiology 3

4. Introduction Venous access Assess & Correction Errors leads to morbidity or mortality. Department of Anesthesiology 4

5. Department of Anesthesiology 5

6. Physiology 6 Department of Anesthesiology British Journal of Anaesthesia , Volume 3 Number 1 2003

7. Osmolality : 285-290 mOsm /kg (both ECF and ICF) ECF: Sodium, Bicarbonate and Chloride ICF: Potassium and Magnesium ECF: volume controlled mainly by- Sodium ( Sensors:- Baroreceptors, Atrial stretch receptors, Juxtaglomerular apparatus) Osmolarity controlled mainly by:- varying water intake and excretion ( Sensors:- Hypothalamus) 7 Department of Anesthesiology

8. Evaluation of Intravascular volume Intravascular volume can be estimated using patient history physical examination laboratory evaluation often with the aid of sophisticated hemodynamic monitoring techniques. Department of Anesthesiology 8

9. Patient History Oral intake Persistent vomiting or diarrhea Gastric suction Significant blood loss or wound drainage Intravenous fluid and blood administration Recent hemodialysis Department of Anesthesiology 9

10. Physical Examination Indications of hypovolemia include abnormal skin turgor dehydration of mucous membranes thready peripheral pulses increased resting heart rate decreased blood pressure orthostatic heart rate and blood pressure changes from the supine to sitting or standing positions decreased urinary flow rate Department of Anesthesiology 10

11. Signs of excess extracellular water and likely hypervolemia in patients with normal cardiac, hepatic, and renal function Pitting edema Increased urinary flow Late signs of hypervolemia in settings such as congestive heart failure may include Tachycardia Tachypnea Elevated jugular pulse pressure Pulmonary crackles, Wheezing Cyanosis Pink, frothy pulmonary secretions Department of Anesthesiology 11

12. 12 Department of Anesthesiology

13. Laboratory Evaluation Laboratory signs of dehydration may include: Rising hematocrit and hemoglobin Progressive metabolic acidosis (including lactic acidosis) Urinary specific gravity greater than 1.010 Urinary sodium less than 10 mEq /L Urinary osmolality greater than 450 mOsm /L Hypernatremia and BUN-to creatinine ratio greater than 10:1 Radiographic indicators of volume overload include: Increased pulmonary vascular and interstitial markings (Kerley “B” lines), diffuse alveolar infiltrates or both. Department of Anesthesiology 13

14. Hemodynamic Measurements Static measures Dynamic measures Central venous pressure Pulmonary artery occlusion pressure Lt ventricular end diastolic area IVC diameter Pulse pressure variation Stroke volume variation (< 10 – 15 % for pts on controlled ventilation) Dynamic changes in aortic flow velocity/ sv assessed by echo Positive pressure ventilation changes in venacaval diameter Department of Anesthesiology 14

15. Cause of Perioperative fluid derragement Perioperative factors Anesthesia related factors Surgery related factors Peroperative fasting Mechanical bowel preparation Disorder like bowel obstruction or pancreatitis On going bleeding typically requires surgical hemostasis Most anesthetics and adjuvant drugs cause dose dependent vasodilation and myocardial depression that may lead to hypotension Sympathetic blockade during neuraxial anesthesia in relative hypovolemia Positive pressure ventilation Haemorrage Coagulopathy Prolonged operative time Decrease venous return d/t abdominal insufflation during laparoscopy Compression of inferior venacava or others major veins Department of Anesthesiology 15

16. Type of fluid 16 Department of Anesthesiology

17. Crystalloids Clear fluids made up of water and electrolyte solutions Will cross a semi-permeable membrane Grouped as isotonic, hypertonic, and hypotonic Eg : Normal saline 0.9%,3 % Dextrose solutions 5 %,10%,20%,25% DNS Ringer’s lactate Isolyte P Department of Anesthesiology 17

18. Advantages Disadvantages Balanced electrolyte solution -Easy to administer -No risk of adverse reactions -No disturbance of hemostasis -Promote diuresis -Inexpensive Poor plasma volume support -Large quantities needed -Risk of Hypothermia -Reduced plasma oncotic pressure -Risk of edema Department of Anesthesiology 18

19. 0.9% Normal Saline Contains: Na+ 154 mmol /l, Cl - - 154 mmol /l Osm : 308mosm/l, pH 6.0 IsoOsmolar compared to normal plasma. Indication : Intravascular resuscitation and replacement of salt loss e.g. diarrhoea and vomiting. Also for diluting packed RBCs prior to transfusion Used for diluting Drugs Department of Anesthesiology 19

20. Distribution: Stays almost entirely in the extracellular space. Of 1 litre - 750ml extra vascular fluid; 250ml intravascular fluid 100ml blood loss – need to give 400ml N. saline [only 25%remains intravascular Complications: When given in large volume can produces Hyperchloremic metabolic acidosis because of highNa + and Cl - content. Department of Anesthesiology 20

21. 0.45% Normal saline = ‘Half’ Normal Saline = HYPOtonic saline Cointais - Na+ 77mmol/l, Cl - 77mmol/l, Osmo 154mOsm/l Indications : Fluid therapy for paediatric pt Maintenance fluid therapy Complications : Leads to HYPOnatraemia if plasma sodium is normal May cause rapid reduction in serum sodium if used in excess or infused too rapidly. This may lead to cerebral oedema and rarely, centralpontine demyelinosis ; Use with caution! Department of Anesthesiology 21

22. 3.0 % Saline = Hypertonic saline 3% contain 513 mmol /l of Na+ and Cl - each, osmol of 1026 mOsm /l pH 5.0 Indications : Treatment of severe symptomatic hyponatremia (coma, seizure) To resuscitate hypovolemic shock Department of Anesthesiology 22

23. Leads to an osmotic gradient between the ECF and ICF, causing passage of fluid into the Extracellular space. Must be administered slowly and preferably with CV line because it carries risk of causing phlebitis Necrosis hemolysis . Complications : Precaution in pt. with CHF severe renal insufficiency, edema with sod. retention. Department of Anesthesiology 23

24. Dextrose 5% Dextrose (often written D5W): 50g/l of glucose, 252mOsm/l, pH 4.5 Regarded as ‘electrolyte free’ – contains NO Sodium, Potassium,Chloride or Calcium Indication : Primarily used to maintain water balance in patients who are not able to take anything by mouth; Commonly used post-operatively in conjunction with salt retaining fluids ie saline Hypernatremia treatment Department of Anesthesiology 24

25. When infused is rapidly redistributed into the intracellular space Side effects: Iatrogenic hyponatraemia in surgical patient Hyperglycemia Not compatible with blood ,cause hemolysis less than 10% stays in the intravascular space therefore it is of limited use in fluid resuscitation Cocn 5% 10% 20% 25% plasma osmolarity 225 505 1010 1262 290 Department of Anesthesiology 25

26. Ringer Lactate Most physiological solution Electrolyte composition similar to ECF One litre of lactated Ringer's solution contains: Sodium ion= 130 mmol /L Chloride ion = 109 mmol /L Lactate = 28 mmol /L Potassium ion = 4 mmol /L Calcium ion = 1.5 mmol /L Osmolarity of 273 , pH of 6.5 Department of Anesthesiology 26

27. Lactate is converted to bicarbonate in liver Indications : Deficit , Intraoperative fluid loss Severe hypovolemia Precautions: Severe metabolic acidosis ( impaired lactate conversion) Don’t give with blood product ( Ca bind with citrate - reduced anticoagulant activity ) Department of Anesthesiology 27

28. DNS 0.9% saline & 5% dextrose Contains - Na+ 154, Cl- 154, 5 gm, Glucose Osm : 432 mosm /L Indication : Maintenance solution Correction of fluid deficit with supply of energy Compatible with blood Department of Anesthesiology 28

29. IsoLyte -P Multiple electrolyte & dextrose solution Na+ : 26 K+ : 20 Mg++ : 3 Cl - : 21 Acetate : 23 Ph+ : 3 Isotonic Indication : Pediatric maintenance fluid Department of Anesthesiology 29

30. Colloids The colloid solutions contain particles which do not readily cross semi-permeable membranes such as the capillary membrane. Thus the volume infused stays (initially) almost entirely within the intravascular space . Stay intravascular for a prolonged period compared to crystalloids. However they leak out of the intravascular space when the capillary permeability significantly changes e.g. Severe trauma or sepsis. Department of Anesthesiology 30

31. Because of their gelatinous properties they cause platelet dysfunction and interfere with fibrinolysis and coagulation factors (factor VIII) – thus they can cause significant coagulopathy in large volumes. Natural : Albumin Artificial : Gelatin and Dextran , Hydroxyethyl starches(HES) Department of Anesthesiology 31

32. colloids Avantages Disadvantages -Prolonged plasma volume support -Moderate volume needed -minimal risk of tissue edema -enhances microvascular flow -Risk of volume overload Adverse effect on haemostasis Anaphylactic reaction - Expensive Department of Anesthesiology 32

33. ALBUMIN Principal natural colloid comprising of 50-60% of all plasma proteins. Synthesized only in liver and has a half life of app. 20 days. 5% soln is iso oncotic and leads to 80% initial vol expansion ,25% soln leads to 200-400% increase in vol. Used For emergency treatment of shock especially due to loss of plasma acute management of burns fluid resuscitation in ICU Hypoalbumineamia Department of Anesthesiology 33

34. Side effects : Pruritis anaphylactoid reactions and coagulation abnormalities as compared to synthetic colloids. Disadvantages cost effectiveness volume overload (in septic shock pt albumin add to interstitial edema) Department of Anesthesiology 34

35. Colloid or Crystalloid Resuscitation Recommendations: Colloid should NOT be used as the sole fluid replacement in resuscitation ,volumes infused should be limited because of side effects and lack of evidence for their continued use in the acutely ill. In severely ill patients – principally use crystalloid and blood products Colloid may be used in limited volume to reduce volume of fluids required or until blood products are available. Department of Anesthesiology 35

36. In elective surgical patients Replace fluid loss with ‘physiological Ringer’s solutions. Blood products and colloid may be needed to replace intravascular volume acutely. Department of Anesthesiology 36

37. Crystalloids vs colloids Crystalloids colloids Low mol wt Iso /hypo/hypertonic Inc hydrostatic pressure Expands interstitial vol T 1/2 -30 minutes Replacement ratio-3:1 Allergic reaction-rare cheap High mol wt Hypertonic Inc oncotic pressure Expands plasma vol T 1/2 -2hrs 1:1 Common Expensive Department of Anesthesiology 37

38. Figure 51-2 morgan Department of Anesthesiology 38

39. Perioperative Fluid Management Goal s Replace pre-operative deficits Provide normal maintenance requirements Replace any intraoperative loss 39 Department of Anesthesiology

40. Perioperative Fluid Management Composition and goals of maintenance fluid Water  to prevent dehydration from insensible loss Glucose  to prevent ketoacidosis and protein degradation Sodium and potassium  prevent electrolyte imbalances Department of Anesthesiology 40

41. Perioperative Fluid Management Maintenance Amount Holliday and Segar formula 41 Department of Anesthesiology

42. Glucose requirement: Up to the age of 8 years  6 mg/kg/min Premature neonates  6–8 mg/kg/min. Older children and adults  2 mg/kg/min Routine use of glucose discouraged Because of its Hypotonicity , increased risk of dehydration and hypoxic brain damage. 42 Department of Anesthesiology

43. SOURCE CAUSES OF INCREASED WATER NEEDS CAUSES OF DECREASED WATER NEEDS Skin Radiant warmer Incubator (premature infant)   Phototherapy     Fever     Sweat     Burns   Lungs Tachypnea Humidified ventilator   Tracheostomy   Gastrointestinal tract       Diarrhea     Emesis     Nasogastric suction   Renal Polyuria Oliguria/anuria Miscellaneous Surgical drain Hypothyroidism   Third spacing   Adjustments in Maintenance Water Department of Anesthesiology 43

44. Deficit Deficit = number of hours NPO x maintenance fluid requirement. 50% replaced in first hour and 50% in next 2 hours Deficit due to fever, vomiting, blood loss, diarrhea Degree of dehydration should be assessed and fluid replaced Eg :- 70 kg pt fasting for 8 hrs Deficit : 8 X 110 = 880 ml Department of Anesthesiology 44

45. Intra Operative Fluid Management Intraoperative losses Third space loss and blood loss Third space loss isotonic transfer of fluid from the ECF to a non-functional interstitial compartment surgical trauma, burn, infection The volume lost is impossible to measure Estimated by the extent of surgery and the clinical response to appropriate fluid replacement 45 Department of Anesthesiology

46. Intra Operative Fluid Management Type of fluid  NS or RL Maintain adequate blood pressure, heart rate, and urine output of 1-2ml/kg/min 46 Department of Anesthesiology British Journal of Anaesthesia | CEPD Reviews | Volume 3 Number 1 2006

47. Blood loss 47 Department of Anesthesiology British Journal of Anaesthesia | CEPD Reviews | Volume 3 Number 1 2003

48. Intra Operative Fluid Management Allowable blood loss ( MABL -Maximum allowable blood loss) ( EBV - Estimated blood volume) Initial replacement should be with crystalloid in a ratio of 3:1 or with colloid in a ratio of 1:1 Platelets and fresh frozen plasma, 10–15 mL/kg, should be given when blood loss exceeds 1–2 blood volumes 48 Department of Anesthesiology

49. The transfusion point can be determined preoperatively from the hematocrit and by estimating blood loss. Patient with normal hematocrit should only be transfused after loss greater than 10 – 20 % of their blood loss. The exact point is based on patient condition and the surgical procedure. Department of Anesthesiology 49

50. The amount of blood loss necessary for the hematocrit to fall to 30% can be calculated as follows:- Estimate blood volume Estimate the RBC volume at the preoperative hematocrit Estimate the RBC volume at the hematocrit of 30%, assuming normal blood volume maintained. Calculate the RBCV lost when the hematocrit is 30%: RBCV lost = RBCV preop – RBCV 30% Alloiwable blood loss = RBCV lost X 3 Department of Anesthesiology 50

51. Example: An 85 kg women has a preoperative hematocrit of 35%. How much blood loss will decrease her hematocrit to 30% ? Here, estimated blood volume = 65ml/kg X 85 kg = 5525 ml RBCV35% = 5525 X 35% = 1934 ml RBCV30% = 5525 X 30% = 11658 ml RBCVlost at 30% = 1934 – 1658 = 276 ml allowable blood loss = 3 X 276 ml = 828 ml There fore, transfusion should be considered only when this patient’s blood loss exceeds 800 ml. Increasingly, transfusion is not recommended until the hematocrit decreases to 24% of lower ( Hb < 8 g/dl), but it is necessary to note the rate of blood loss and comorbid conditions. Department of Anesthesiology 51

52. Clinical guideline commonly used include: One unit of RBC raises hemoglobin by 1g/ dL (or raises HCT 3%) 10 mL /kg transfusion of RBC will Increases the hemoglobin by about 3 g/ dL and hematocrit by 10% Department of Anesthesiology 52

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55. Reference Millers 7th edition Clinical Anesthesiology- Morgan 5th edition Clinical Anesthesia Barash 7th edition Department of Anesthesiology 55

56. THANK YOU Department of Anesthesiology 56