Perioperative Fluid Management by ANIRBAN.pptx

a short description about perioperative fluid management

1. Perioperative Fluid Management Dr Nilima Afrin Anirban Anesthesiologist Shaheed Ziaur Rahman Medical College and Hospital, Bogura

2. The perioperative period is associated with significant alteration in fluid balance. Adequate fluid therapy in these periods is essential to meet adequate ECFV ,circulating volume, cardiac output and tissue oxygen delivery. The ultimate goal is to reduce perioperative morbidity and mortality

3. Distribution of total body water

4. Daily fluid requrement Daily fluid requirement is = urine output + 700 ml

5. Approximate electrolyte contents of body fluid

6. Body water balance maintenance

7. Continued….

8. Type of intravenous fluid

9. Crystalloids Aqueous solutions of ions (salt) with or without glucose.

10. Colloids Contains high molecular weight substances e.g. proteins, large glucose polymers which maintains plasma colloid oncotic pressure.

11. Evaluation of intravascular volume

12. Continued… Physical examination : Vital signs : BP, HR, RR, GCS, urine output. Signs of dehydration

13. Continued… Intraoperatively: volume status assessment by heart rate, BP, fullness of peripheral pulse, urine flow rate, indirect signs e.g. blood pressure response to positive pressure ventilation and anaesthetics Signs of hypervolemia : increased urinary flow, then in ambulatory patient: pitting edema, in bed-ridden patient: presacral edema . In pt of congestive cardiac failure: tachycardia, tachypnoea, cyanosis, pink frothy sputum, creps in lung base, raised JVP.

14. Continued.. Laboratory signs of dehydration : increasing haematocrit and Hb, progressive metabolic acidosis, hypernatremia, BUN to creatinine ratio >10:1 urinary specific gravity greater than 1.010, urinary sodium < 10 mmol/l, urinary osmolality >450 mOsm /l , Haemodynamic monitoring: CVP, PAOP etc

15. Perioperative fluid management

16. Aims of perioperative fluid therapy

17. Maintenance fluid Selection of fluid for maintenance: Balanced salt solution without dextrose as surgery & anaesthesia themselves provoke hyperglycaemia due to stress. E.g. ringer’s lactate

18. Preexisting deficit It proportionate to duration of fast. It is estimated by multiplying the normal maintenance rate and duration of fast. E.g. for average 70 kg person fasting for 8 hour: Maintenance fluid is on 4:2:1 rule : (40+20+50)ml/hr=110 ml/hr Deficit fluid will be: (110*8)=880ml/hr Abnormal fluid losses ( preoperative bleeding, vomiting, NG suction, diuresis, diarrhoea, fluid sequestration by infected tissue, hematoma, ascites) often contributory to deficit.

19. Surgical losses

20. Other fluid losses a. Evaporative loss: significant to large wound, proportional to exposed surface area & duration of surgery. b. Internal redistribution of fluid/ third space loss: traumatized tissue sequester large amount of fluid in peritonitis, burn, asciets

21. Hourly Calculation of intraoperative fluid 1. Maintenance fluid ( 4/2/1 rule) 2.Fasting deficit ( maintenance fluid* duration of fasting) 50% of deficit given in 1 st hour, 25% in 2 nd hour & 25% in 3 rd hr 3.Replacement fluid : evaporative loss+ 3 rd space loss+ blood loss

22. Replacing blood loss Present day approach is towards minimum use of blood products. Known as restrictive approach . Patient with normal haematocrit usually transfused after 10-20% losses of their blood volume. Transfusion trigger : in normal pt: Hb level 8 gm/dl ,in pt with comorbidity e.g. older, sicker, cardiac disease, pulmonary disease this trigger would be 9-10 gm/dl. For transfusion decision should be taken on further blood loss, rate of blood loss, comorbidity etc

23. Continued….. For transfusion decision should be taken on further blood loss, rate of blood loss, comorbidity etc Except massive trauma, most clinicians administer lactated Ringer’s solution or plasmalyte in approximately 3-4 times the volume of blood loss. If colloid is used, then colloid should be replaced as equal volume of blood loss until transfusion trigger is reached

24. Calculation of allowable blood loss

25. Goal directed fluid therapy In critically ill patient, tissue oxygen delivery is optimized through “physiological goal’’ related to cardiac output & fluid administration. Based on hemodynamic variables e.g. stroke volume, cardiac output, cardiac index, mean arterial pressure

26. Fluid for certain clinical situations Paediatric patient: In acutely unwell & dehydrated child ,at first correction of dehydration as: Mild dehydration ( 5% body weight loss= 50ml/kg deficit) Moderate dehydration ( 10% body weight loss= 100ml/kg deficit) Severe dehydration ( 15% body weight loss= 150ml/kg deficit) Then maintenance and replacement fluid correction If no dehydration, then deficit correction based on duration of fasting & thereafter maintenance & replacement correction

27. Continued….

28. Postoperative fluid therapy Based on patient’s current estimated volume status & ongoing losses. Any pre/intraop. deficit should be corrected + maintenance fluid+ ongoing loss should be replaced. In case of paediatric pt. maintenance fluid should be reduced to 50-60% to reduce tissue oedema. Monitoring: vital signs, urine output, electrolyte . i/v fluid should be discontinued when pt is able to take oral fluid

29. Drawbacks of inappropriate perioperative fluid therapy

30. Liberal vs Restrictive fluids The largest multicentred randomized control trial found that, in major noncardiac surgery, “moderately liberal ” strategy (10-12ml/kg/hr intraop &1.5ml/kg/hr in following 24hr post-surgery) is helpful at end of surgery, Here positive fluid balance of 1-2l by isotonic balanced crystalloid solution is helpful. Other major surgeries which don’t result in major fluid shifts are unlikely to require as much fluid.

31. Maintaining euvolemia is the goal. Both hypovolemia & hypervolemia are associated with postoperative morbidity. To ensure enhanced recovery, appropriate fluid management is essential. In critically ill patient Goal directed fluid therapy is helpful NPO duration should be minimized. Special precaution must be taken in high-risk cases ( elderly, children, kidney disease etc)