Perioperative Fluid Management

Transcription

1 Perioperative Fluid Management A. Scott Keller October 22, MFMER slide-1

2 Or 2016 MFMER slide-2

3 Mr. Anesthesiologist, please don t drown my patient! 2016 MFMER slide-3

4 Disclosures No relevant financial disclosures MFMER slide-4

5 Learning Objectives Describe perioperative fluid physiology. Estimate perioperative fluid requirements. Explain when diuretics are needed postoperatively. Discuss the limitations of using urine output to determine intravascular volume in the perioperative period MFMER slide-5

6 Perioperative fluid management is not a new concern 2016 MFMER slide-6

7 WG Maddock: Water Balance in Surgery It is difficult to lay down hard and fast rules to cover the proper administration of saline solutions to all patients MFMER slide-7

8 Paging On-Call (That s You!) 8:00 PM--You ve just taken sign out for the night shift at Outside Hospital. 8:05 PM--You re reviewing patient notes, including Mr. Hip, a 67-yo male s/p left revision THA this morning. 8:10 PM--Mr. Hip s nurse pages you about his low urine output: Can you come see this patient? 2016 MFMER slide-8

9 First Case: Low Urine Output Urine output of 100 cc in last 6 hours. BP 80/40, HR 100, T 37.4, RR 16, weight 106 kg (pre-op weight 100 kg). NAD, no pain, but mild nausea and no oral intake, urine is amber colored, lungs are clear. He took his usual atenolol 25 mg before surgery, no other chronic meds. Labs: Hgb 9 (13), creat 1.0 (1.0) MFMER slide-9

10 First Case: Low Urine Output Review of his chart shows EBL of 1000 cc. His total intra-op fluids were 7300 cc in and 1300 cc out. 6 liters positive fluid balance!!! He is still receiving NS at 140 cc/hr MFMER slide-10

11 What is the most appropriate initial treatment? A. Call the anesthesiologist and yell at him/her for drowning your patient. B. Give furosemide 40 mg IV STAT. C. Monitor for another 12 hours because decreased urine output is expected in the immediate post-op period. D. Give fluid bolus of 500 cc over 1 hour, repeat if necessary. E. Check a UA and consult Nephrology MFMER slide-11

12 Second Case: Low Urine Output Urine output of 100 cc in last 6 hours. BP 130/70, HR 100, T 37.4, RR 16, weight 106 kg (pre-op weight 100 kg). NAD, no pain, but mild nausea and no oral intake, urine is amber colored, lungs are clear. He took his usual atenolol 25 mg before surgery, no other chronic meds. Labs: Hgb 9 (13), creat 1.0 (1.0) MFMER slide-12

13 Second Case: Low Urine Output Review of his chart shows EBL of 1000 cc. His total intra-op fluids were 7300 cc in and 1300 cc out. 6 liters positive fluid balance!!! He is still receiving NS at 140 cc/hr MFMER slide-13

14 What is the most appropriate initial treatment? A. Call the anesthesiologist and yell at him/her for drowning your patient. B. Give furosemide 40 mg IV STAT. C. Monitor for another 12 hours because decreased urine output is expected in the immediate post-op period. D. Give fluid bolus of 500 cc over 1 hour, repeat if necessary. E. Check a UA and consult Nephrology MFMER slide-14

15 Pre-Test Questions Test Your Knowledge! 2016 MFMER slide-15

16 Question #1: Which one of the following is true? A. Most IV crystalloid leaks out of the intravascular space into the interstitium. B. Induction of anesthesia causes relative intravascular hypervolemia. C. It is best to avoid IV fluids post-op since patients get sufficient fluid during surgery MFMER slide-16

17 Question #2: All of the following are true except A. Urine output (UOP) is expected to decrease during surgery. B. UOP generally increases around POD 2. C. Low UOP post-op means acute kidney injury. D. Perioperative urine output does not correlate with intravascular volume status MFMER slide-17

18 Question #3: Which is the best scenario to give furosemide? A. Post-op low urine output. B. Post-op lower extremity edema. C. Post-op pulmonary edema. D. Always continue furosemide perioperatively if patient takes it chronically MFMER slide-18

19 The Job of the Anesthesiologist 2016 MFMER slide-19

20 The Job of the Anesthesiologist Induce unconsciousness/amnesia. Provide analgesia. Maintain a quiescent surgical field. Optimize hemodynamic function and organ/tissue perfusion. Avoid volume excess, including lung fluid accumulation MFMER slide-20

21 Things That Worry the Anesthesiologist Underlying medical conditions CAD and CHF. Aortic stenosis. Asthma. Pulmonary hypertension. Renal insufficiency. Response to the surgical procedure Effects of anesthesia. Sympathetic stimulation. Blood loss and fluid shifts MFMER slide-21

22 Fundamental Difficulty Usual physiologic response to hypovolemia in a conscious person is vasoconstriction and tachycardia. These responses can compensate and mask underlying intravascular depletion until 10-20% blood loss. These mechanisms are blunted or abated by anesthesia, making estimates of volume loss more complex static measures aren t accurate MFMER slide-22

23 Fundamental Difficulty So how can we monitor and maintain intravascular volume? The short answer it s complicated. We ll talk about the longer answer. For Mr. Hip, we need to determine if he has too much or too little fluid and what to do about it MFMER slide-23

24 First, let s look at some physiology 2016 MFMER slide-24

25 Review of Physiology Cardiac output = SV x HR. SV is a function of preload, afterload, and contractility. Blood pressure is a function of CO and SVR. Reduced tissue perfusion can be due to low cardiac output or vasoconstriction of organs MFMER slide-25

26 Review of Physiology Reduced tissue perfusion can be seen with hypovolemia, euvolemia, or hypervolemia! 2016 MFMER slide-26

27 Frank-Starling s Law Too Much Volume = Decreased SV Stroke Volume Maximum EDV, Maximum SV More Blood in Heart Means More Gets Pumped Out! Normal Range, SV Increases with EDV End-Diastolic Volume 2016 MFMER slide-27

28 So what does this mean? The foundation for cardiovascular function: Maintenance of proper intravascular volume Maintenance of ventricular preload (end diastolic volume) and SV. The anesthesiologist must carefully control the volume and preload/sv during the surgical procedure, and avoid extravascular excess MFMER slide-28

29 More Physiology (!) 2016 MFMER slide-29

30 Blood Flow Starling Forces Inside Capillary Capillary Hydrostatic Pressure Oncotic Pressure Excess Fluid Enters Lymphatics Lymphatic Vessel To Venous Circulation 2016 MFMER slide-30

31 Body Fluid Compartments Total Body Water ICFV (66%) ECFV (34%) ISFV (75%) PV (25%) V (85%) A (15%) 2016 MFMER slide-31

32 Distribution of Body Fluid: Normal 66% 34% ISFV 75% Intracellular Fluid Volume PV 25% Extracellular Fluid Volume Negligible Third-Spaced Fluid 2016 MFMER slide-32

33 What if the patient has an injury or surgery? 2016 MFMER slide-33

34 Third Spacing Analogous to hitting your thumb with a hammer local tissue swelling MFMER slide-34

35 Distribution of Body Fluid: Acute Injury Intracellular Fluid Volume ISFV PV Extracellular Fluid Volume Third-Spaced Fluid (Site of Injury) Site of Injury 2016 MFMER slide-35

36 More About Third Spacing Likely mechanism is tissue trauma and increased vascular permeability ( leakiness ) due to surgical inflammation (release of IL6, IL8, TNF-α). Mostly a temporary phenomenon that persists for 1-3 days with subsequent fluid mobilization (may take longer in elderly patients). Lymphatics are initially overwhelmed, then can catch up and remove fluid MFMER slide-36

37 More About Third Spacing Where exactly is the third space? No one really knows! (Is it real?) Tracer methods to look for blood or fluid extravasation and shifts have been inconsistent. The third space may simply be the interstitium or sequestered fluid. D Chappell et al, A Rational Approach to Perioperative Fluid Management. Anesthesiology 2008; 109: MFMER slide-37

38 What if we give IV fluids? 2016 MFMER slide-38

39 IV Fluids and Third Spacing Most IV crystalloid leaks out of the intravascular space into the interstitium. Thus, the more IV fluid given to replete the vascular space, the more third-spacing (or at least shifting from the intravascular space to the interstitium) will occur! 2016 MFMER slide-39

40 More About IV Fluid Therapy Crystalloid (NS, LR) replacement 3:1 if small blood loss But geometric increase in transcapillary leakage with higher blood loss (less alb) - 5:1 if 35% blood loss! - 16:1 if 75% blood loss!! Blood, colloid Replace 1:1 PJ Neligan et al. Monitoring and Managing Perioperative Electrolyte Abnormalities, Acid- Base Disorders, and Fluid Replacement. Longnecker s Anesthesiology. Access Medicine, McGraw-Hill MFMER slide-40

41 Distribution of Body Fluid: IV Fluid Infusion Blood pressure improves as PV increases ISFV PV Intracellular Fluid Volume Extracellular Fluid Volume Third-Spaced Fluid (Site of Injury) 2016 MFMER slide-41

42 Blood vs IV Fluids Fluid Na meq/l Cl meq/l K meq/l Ca meq/l Bicarb meq/l Glu g/l Alb g/l mosm/kg Blood NS /2NS LR D % Alb Note: Calcium 5 meq/l x 1L/10dL x 40 mg/mmol x 1mmol/2mEq = 10 mg/dl 2016 MFMER slide-42

43 IV fluids are IV drugs! The selection, timing, and doses of intravenous fluids should be evaluated as carefully as they are in the case of any other intravenous drug, with the aim of maximizing efficacy and minimizing iatrogenic toxicity. JA Myburgh and MG Mythen. Resuscitation Fluids, N Engl J Med 2013;369: MFMER slide-43

44 Controversy: Crystalloid vs Colloid Crystalloids are solutions of crystalline substance such as NaCl, KCl, or glucose in water. Colloids are expensive suspensions of macromolecules (not solutions) in a water- or saline-based medium (albumin, hetastarch, dextran). Colloids theoretically stay in vascular space, but no consistent benefit MFMER slide-44

45 Controversy: Crystalloid vs Colloid Only about 20-25% of LR and NS stay in circulation (about 1-4 h) vs % of albumin 5% (12-24 h) and % of hetastarch (8-36 h).* High volumes of NS can cause hyperchloremic NAGMA.* Cl - vasoconstricts, may splanchnic and renal blood flow, LR may be best crystalloid in many situations, but may cause hyponatremia. *Am J Respir Crit Care Med 2004;170: MFMER slide-45

46 Perioperative Fluid Theory 2016 MFMER slide-46

47 A Tough Act The anesthesiologist has to ensure enough fluid to maintain intravascular volume and SV while avoiding volume excess. This is especially critical for underlying medical conditions like heart failure and CKD. Remember that static measures aren t helpful to assess volume MFMER slide-47

48 Five Phases of the Perioperative Period Pre-op dehydration phase. Shock phase causing absolute hypovolemia in extracellular space Vasoconstriction. Shunting of blood to vital organs. Decreased capillary hydrostatic pressure. PJ Neligan et al. Monitoring and Managing Perioperative Electrolyte Abnormalities, Acid-Base Disorders, and Fluid Replacement. Longnecker s Anesthesiology, Access Medicine, McGraw-Hill MFMER slide-48

49 Five Phases of the Perioperative Period Relative and absolute hypovolemic phase (as a consequence of vasodilatation, fluid sequestration from increased capillary permeability, and blood loss). Diuresis phase ( mobilize fluid ). Equilibrium phase (POD 2). PJ Neligan et al. Monitoring and Managing Perioperative Electrolyte Abnormalities, Acid-Base Disorders, and Fluid Replacement. Longnecker s Anesthesiology, Access Medicine, McGraw-Hill MFMER slide-49

50 Dehydration vs Hypovolemia vs Relative Volume Depletion Dehydration: loss of free water, leads to [Na+]. Hypovolemia: loss of both water and electrolytes/proteins, or blood. Relative volume depletion: dilation of blood vessels without necessarily losing fluid. Full Vessel Same amount of blood! 2016 MFMER slide-50

51 Controversy Different Strategies to Replace Intravascular Volume Losses Liberal/traditional fluid Typically formula-based. Idea is to maintain hemodynamics and perfusion above all else. Restrictive/zero balance fluid New thinking over last decade. Idea is to minimize tissue edema while optimizing perfusion. Goal-directed therapy/hybrid Use intraoperative TEE to monitor SV MFMER slide-51

52 What about fluids for hip surgery patients? Five studies including a total of 403 participants provided no evidence that fluid optimization strategies improve outcomes for participants undergoing surgery for proximal femur fracture. Further research powered to test some of these outcomes is ongoing. SR Lewis SR et al. Perioperative fluid volume optimization following proximal femoral fracture (Review). Cochrane Database of Systematic Reviews 2016, Issue MFMER slide-52

53 Perioperative Fluid Losses Pre-operative losses. Intraoperative losses. Postoperative losses. Fluids need to be given to compensate for these losses MFMER slide-53

54 Intraoperative Fluid Losses Induction of anesthesia (relative loss) Causes decreased venous return Decreased SVR (vasodilation). Reduced myocardial contractility. Effects are from inhalation, IV anesthetic agents, and spinal anesthesia. Also can be due to positive pressure ventilation and many muscle relaxants MFMER slide-54

55 Intraoperative Fluid Losses Other factors that alter venous return and vascular tone (relative loss) Patient positioning. Surgical packing and retraction. Patient temperature. Orthopedic bone cement (causes significant vasodilation) MFMER slide-55

56 Intraoperative Fluid Losses Direct fluid requirements Maintenance fluids. Insensible losses (evaporation from the surgical exposure and respiratory losses). Bleeding. Fluid shifts ( third spacing ) MFMER slide-56

57 Maintenance Fluids Estimate as 1 cc per kg per hour plus 40 cc per hour (one approach). For a 100 kg patient, this is 140 cc per hour. The patient s NPO time should be compensated with additional real-time maintenance fluid MFMER slide-57

58 Compensation for Third Spaced Fluid and Insensible Losses Different surgeries have different estimated compensation requirements (cc/kg/h): Minimal trauma, 2 4 cc/kg/h Moderate trauma, 4 6 cc/kg/h Extensive trauma, 6 12 cc/kg/h This Formula-Based Approach May Not Always Be Best PJ Neligan et al. Monitoring and Managing Perioperative Electrolyte Abnormalities, Acid-Base Disorders, and Fluid Replacement. Longnecker s Anesthesiology. Access Medicine, McGraw-Hill MFMER slide-58

59 Other Concerns Transient intra-op hypotension may require fluid boluses and/or vasopressors Excessive bleeding. Bone cement. Change in patient position. Release of tourniquet (inrush of blood plus lactic acidosis). Marrow fat emboli during reaming MFMER slide-59

60 Other Indications for Fluid Administration Medications. Need for coagulation factor transfusion. Endotoxin and sepsis. Allergic or anaphylactic reactions. Electrolyte imbalance. Acid-base balance. Nutrition and glucose requirements MFMER slide-60

61 What about the need for fluids after surgery? The Role of the Hospital Provider 2016 MFMER slide-61

62 Postoperative Fluid Losses Continued capillary leakage for hours (postoperative inflammation). Ongoing bleeding. Surgical drains. Poor po with nausea and vomiting. PJ Neligan et al. Monitoring and Managing Perioperative Electrolyte Abnormalities, Acid-Base Disorders, and Fluid Replacement. Longnecker s Anesthesiology, Access Medicine, McGraw- Hill MFMER slide-62

63 Postoperative Fluid Losses Evaporative losses. NG tube. Urine output. Diarrhea. PJ Neligan et al. Monitoring and Managing Perioperative Electrolyte Abnormalities, Acid-Base Disorders, and Fluid Replacement. Longnecker s Anesthesiology, Access Medicine, McGraw- Hill MFMER slide-63

64 How to determine post-op intravascular volume? 2016 MFMER slide-64

65 Usual Assessment of Intravascular Volume: Exam Too little: Blood pressure and heart rate. Orthostatics. Dry mucous membranes. Loss of skin turgor. Dark urine color, decreased output. Too much: Lung crackles. Jugular venous pressure/ajr. S3. Peripheral edema MFMER slide-65

66 Usual Assessment of Intravascular Volume: Tests Laboratory studies Serum sodium. BNP. BUN:creatinine ratio. Urine indices (electrolytes, osm, SG). Imaging studies CXR. Chest CT MFMER slide-66

67 Are these helpful post-op? Exam findings may not be helpful BP and HR increased due to surgical stress, pain, anxiety. Orthostatics not reliable if bedbound. Mucous membranes not helpful if NPO. Urine output not always helpful, as we ll see MFMER slide-67

68 What about weight? Many authorities suggest this is best way to assess volume changes. 10% gain above preoperative weight, has been associated with increased morbidity, length of ICU stay, and postoperative mortality.* Personal experience--many sources of error, but can be helpful. *JA Lowell et al, Postoperative Fluid Overload: Not a Benign Problem. Crit Care Med 1990; MFMER slide-68

69 Use of Echocardiography to Estimate Intravascular Volume cardio/cgi-bin/mediawiki/index.php/ivc 2016 MFMER slide-69

70 Use of Echocardiography to Estimate Intravascular Volume cardio/cgi-bin/mediawiki/index.php/ivc 2016 MFMER slide-70

71 What about post-op urine output? 2016 MFMER slide-71

72 Profound Quotes from Smart People Intraoperative oliguria, defined as urine output less than 0.5 ml/kg/h, was not associated with renal failure. S Kheterpal et al. Predictors of Postoperative Acute Renal Failure after Noncardiac Surgery in Patients with Previously Normal Renal Function. Anesthesiology 2007;107(6): MFMER slide-72

73 Profound Quotes from Smart People Intraoperative urine formation depends on a number of factors and is an insensitive and unreliable method for assessing postoperative risk of renal dysfunction. RD Miller. Miller's Anesthesia, 7 th Edition, Chapter 45, pp Churchill Livingstone MFMER slide-73

74 Profound Quotes from Smart People Low hourly urine flow (<0.5 ml/kg/hr) is a marker in some widely used criteria to diagnose AKI but is not a meaningful assessment to make this diagnosis in the immediate perioperative period. RD Miller. Miller's Anesthesia, 7 th Edition, Chapter 45, pp Churchill Livingstone MFMER slide-74

75 Profound Quotes from Smart People Postoperative oliguria should be expected and accepted, as urine output does not indicate overall fluid status. R Gupta and TJ Gan. Peri-Operative Fluid Management to Enhance Recovery. Anaesthesia 2016, 71 (Suppl. 1), MFMER slide-75

76 Profound Quotes from Smart People Our findings support the hypothesis that ARF is not prevented by striving toward a predefined urine output target. M Egal et al. Targeting Oliguria Reversal in Goal-Directed Hemodynamic Management Does Not Reduce Renal Dysfunction in Perioperative and Critically Ill Patients: A Systematic Review and Meta-Analysis. Anesth Analg 2016;122: MFMER slide-76

77 Profound Quotes from Smart People fluid administration solely for the purpose of increasing urine output is not indicated and may lead to fluid overload. GP Joshi. Intraoperative fluid management. UpToDate MFMER slide-77

78 Say what?!? 2016 MFMER slide-78

79 Urine Output Multiple factors may affect urine output Intravascular depletion ( ) Natural Na and water conservation ( ) AKF ( ) Diuretics ( ) Hyperglycemia ( ) Volume overload ( ) 2016 MFMER slide-79

80 Response to Blood Loss and Hypovolemia Anti-Diuretic Hormone--natural protective measure to conserve Na and water. Helps the body to maintain cardiac output and organ perfusion MFMER slide-80

81 Anti-Diuretic Hormone Stimulated by volume contraction, hypotension, pain, N/V, opioids, and SURGICAL STRESS AND POSITIVE- PRESSURE VENTILATION Also, two very common drugs potentiate the renal action of ADH NSAIDs AND ACETAMINOPHEN 2016 MFMER slide-81

82 Anti-Diuretic Hormone The result of ADH is DECREASED URINE OUTPUT. So how useful is measurement of urine output to determine intravascular volume status? May be a reasonable surrogate marker if you understand the timing of expected fluid shifts MFMER slide-82

83 Expected Urine Output Decreases during surgery and immediately following surgery ( ADH). Should increase over the next hours post-op as surgical stress resolves and hormonal mechanisms normalize. Should increase significantly with fluid mobilization around day 2-3 as inflammation/capillary permeability subsides (longer in elderly patients) MFMER slide-83

84 Expected Urine Output Multiple factors can change this: Large intra-op blood loss. Patient took diuretic pre-op. Prolonged hypotension. Acute kidney injury/failure (ATN most common). Massive tissue trauma with on-going hemorrhage and third spacing. Low albumin (?acute phase reactant vs poor nutrition) MFMER slide-84

85 For postoperative patients with decreased urine output Best treatment is to give fluids only if clinical volume depletion or true oliguria, or else risk for pulmonary edema (more later). Otherwise, may need to limit free water to minimize hyponatremia related to ADH. Periodically check creatinine. No need for concern unless creat is increasing-- no kidney failure if creat is normal unless remains oliguric/anuric MFMER slide-85

86 In immediate postop setting, low urine output does not equal acute kidney failure! 2016 MFMER slide-86

87 For postoperative patients with decreased urine output Remember, post-op patients are trying to conserve Na and water with increased ADH. No need to check urine output every hour, just monitor over 6-12 hour period MFMER slide-87

88 However Caution if true oliguria (<400 cc in 24 hours). Change in creat can lag behind insult, so be aware of possible AKI/AKF. Preop risk factors (CKD, DM)? Periop insults (hypotension, volume loss)? May consider checking NGAL if concern and risk factors for AKI/AKF (see Appendix) MFMER slide-88

89 What about furosemide? For patients who chronically take furosemide, I usually hold it the day of and the day after surgery (unless acute HF). Do not routinely give furosemide just because of low urine output. Even if intravascular volume depletion, furosemide can increase urine output! Monitor creat, BUN, and bicarb when giving furosemide to help determine if intravascular depletion MFMER slide-89

90 What if low urine output makes you nervous? If low UOP despite normal vitals and creat, can give tiny doses of furosemide 5 mg IV to counter effects of ADH. No evidence that furosemide improves outcomes in AKF*, but does not appear to increase mortality.** May be useful in patients at risk for fluid overload as they begin to mobilize third-spaced edema. *KM Ho and DJ Sheridan, Meta-Analysis of Frusemide to Prevent or Treat Acute Renal Failure. BMJ **S Uchino et al, Diuretics and Mortality in Acute Renal Failure. Crit Care Med 2004; 32: MFMER slide-90

91 When to give furosemide? Pulmonary edema is major indication Arieff and colleagues suggest that fluid retention >67 ml/kg/day can lead to pulmonary edema within the initial 36 hours post-op.* Also in post-op hypertension despite usual meds and adequate pain control (if evidence of intravascular volume overload). *AI Arieff. Fatal postoperative pulmonary edema: pathogenesis and literature review. Chest 1999; 115: MFMER slide-91

92 When to give furosemide? Patients with conditions like heart failure, chronic kidney disease, and mitral stenosis are at higher risk to develop pulmonary edema. Patients with cardiac ischemia/ami post-op may also develop pulmonary edema MFMER slide-92

93 When to give furosemide? These high-risk patients may need cautious diuresis beginning hours post-op, especially as they begin to mobilize the third-spaced fluid 1-3 days post-op (use caution in patients with severe aortic stenosis). Fortunately, most healthy patients will autodiurese the extra fluid with no problems MFMER slide-93

94 Back to our patient, Mr. Hip 2016 MFMER slide-94

95 Intra-op Fluid Therapy (Crystalloid) NPO compensation is 140 cc for 8 hours = 1120 cc. Replace ½ the deficit in the first hour, then ¼ over each of the next two hours. Intra-op maintenance for a 3 hour surgery is 140 cc x 3 = 420 cc. Blood loss (3:1) = 3 liters NS or LR (could consider 1:1 colloid instead). Medications = 260 cc MFMER slide-95

96 Intra-op Fluid Therapy (Crystalloid) Compensation for hypotension at induction, with bone cement, and transient episodes = 1000 cc (could consider phenylephrine also). Fluid for third spacing and insensible losses = 500 cc/h for three hours = 1500 cc. Total intra-op fluid administration = = 7300 cc! Net = (EBL + UOP) = 6000 cc! 2016 MFMER slide-96

97 Intra-op Fluid Therapy Almost all of the fluid given in this case was appropriate to compensate for pre-op and intra-op losses. The fluid was necessary to maintain adequate tissue perfusion with the goal of being euvolemic MFMER slide-97

98 Answer to the First Case Mr. Hip is hypotensive in the setting of surgery with low urine output. He took his usual atenolol, plus he may have effects of anesthesia and opioids. Despite being 6 L fluid positive, concern for intravascular volume depletion, possibly bleeding MFMER slide-98

99 What is the most appropriate initial treatment? A. Call the anesthesiologist and yell at him/her for drowning your patient. B. Give furosemide 40 mg IV STAT. C. Monitor for another 12 hours because decreased urine output is expected in the immediate post-op period. D. Give fluid bolus of 500 cc over 1 hour, repeat if necessary. E. Check a UA and consult Nephrology MFMER slide-99

100 Answer to the Second Case Mr. Hip is normotensive in the setting of surgery and low urine output. This most likely represents the effect of increased ADH. He does not need any specific treatment at this time. He should be closely monitored to make sure his UOP improves as expected MFMER slide-100

101 What is the most appropriate initial treatment? A. Call the anesthesiologist and yell at him/her for drowning your patient. B. Give furosemide 40 mg IV STAT. C. Monitor for another 12 hours because decreased urine output is expected in the immediate post-op period. D. Give fluid bolus of 500 cc over 1 hour, repeat if necessary. E. Check a UA and consult Nephrology MFMER slide-101

102 Post-Test Questions What Have You Learned? 2016 MFMER slide-102

103 Question #1: Which one of the following is true? A. Most IV crystalloid leaks out of the intravascular space into the interstitium. B. Induction of anesthesia causes relative intravascular hypervolemia. C. It is best to avoid IV fluids post-op since patients get sufficient fluid during surgery MFMER slide-103

104 Question #2: All of the following are true except A. Urine output (UOP) is expected to decrease during surgery. B. UOP generally increases around POD 2. C. Low UOP post-op means acute kidney injury. D. Perioperative urine output does not correlate with intravascular volume status MFMER slide-104

105 Question #3: Which is the best scenario to give furosemide? A. Post-op low urine output. B. Post-op lower extremity edema. C. Post-op pulmonary edema. D. Always continue furosemide perioperatively if patient takes it chronically MFMER slide-105

106 Take-Home Point #1 The goal of perioperative fluid management is to maintain tissue perfusion without excess extravascular fluid MFMER slide-106

107 Take-Home Point #2 Basic physiologic principles, including the Frank-Starling curve, govern intravascular volume status CO = SV x HR. Frank-Starling curve. Starling forces inside capillaries. Distribution of body fluids and third-spacing MFMER slide-107

108 Take-Home Point #3 Urine output is not an accurate gauge of intravascular volume, but may be a reasonable surrogate based on timing of expected fluid shifts MFMER slide-108

109 Finally The need for post-op fluid restriction and diuresis is NOT evidence of excess fluid administration, but rather of altered time- and disease-related pathophysiology. You have to give what the patient is asking for in the moment and then deal with the consequences. Most kidneys are smarter than most humans. --David Morris, MD MFMER slide-109

110 Remember Anesthesiologists do NOT intentionally drown our patients! In your preop evaluation, do not say avoid fluid overload the anesthesiologists know this! 2016 MFMER slide-110

111 Summary of What I Do Monitor hemodynamics and pulmonary status, may need IVF. Calculate ins and outs, check weights. Watch urine output to make sure trend is as expected. Monitor creatinine. If chronically on a diuretic, resume around POD 1-2 as allowed by hemodynamics. May need diuretic if pulmonary edema or HTN MFMER slide-111

112 As hospital-based providers, we should understand and acknowledge the work of our anesthesia colleagues, and we should provide appropriate post-op monitoring MFMER slide-112

113 Minnesota Fluid Theory 2016 MFMER slide-113

114 2016 MFMER slide-114

115 With your excellent medical care, we can get our patients back in the game 2016 MFMER slide-115

116 Thank you for your attention! 2016 MFMER slide-116

117 Questions? 2016 MFMER slide-117

118 Appendix 2016 MFMER slide-118

119 NGAL Urine NGAL: Neutrophil Gelatinase-Associated Lipocalcin. Produced and secreted by kidney tubule cells at low levels. Amount produced and secreted into the urine increases dramatically after ischemic, septic, or nephrotoxic injury of the kidneys MFMER slide-119

120 NGAL Analogous to troponin can detect kidney injury within 2 hours after ischemic injury associated with cardiac surgery or after contrast-induced nephropathy. Elevation precedes increase in creat by 12 to 24 hours. Highly predictive of the subsequent development of acute kidney injury MFMER slide-120

121 NGAL So, if decreased urine output and concerning history (CKD, prolonged hypotension during surgery, severe sepsis, contrast dye or other nephrotoxic meds like NSAIDs, etc): Consider checking NGAL. Make sure volume replete. Treat as if AKI/AKF while closely monitoring (kidney diet, adequate blood pressure, avoid nephrotoxic meds, adjust med dosages) MFMER slide-121

122 Excellent Reviews of Perioperative Fluid Management MA Hamilton. Perioperative fluid management: progress despite lingering controversies. CCJM 2009;76(4):S28-S31. GP Joshi. Intraoperative fluid management. UpToDate MFMER slide-122

123 Controversy: Crystalloid vs Colloid D Annane et al. Effects of Fluid Resuscitation with Colloids vs Crystalloids on Mortality in Critically Ill Patients Presenting with Hypovolemic Shock. JAMA 2013;310(17): Among ICU patients with hypovolemia colloids vs crystalloids did not result in a significant difference in 28-day mortality MFMER slide-123

124 Controversy: Crystalloid vs Colloid P Caironi et al. Albumin Replacement in Patients with Severe Sepsis or Septic Shock. N Engl J Med 2014; 370: In patients with severe sepsis, albumin replacement in addition to crystalloids, as compared with crystalloids alone, did not improve the rate of survival at 28 and 90 days MFMER slide-124

125 Hydroxyethyl Starch Solutions: FDA Safety Communication - Boxed Warning on Increased Mortality and Severe Renal Injury and Risk of Bleeding June 11, 2013 Do not use HES solutions in critically ill adults. Avoid if pre-existing renal dysfunction. Discontinue at first sign of AKI or coagulopathy. Need for renal replacement therapy has been reported up to 90 days after HES administration. Monitor renal function for at least 90 days in all patients. Avoid use in open heart surgery with CPB due to excess bleeding MFMER slide-125

126 Additional References and Further Reading B Brandstrup et al. Which goal for fluid therapy during colorectal surgery is followed by the best outcome: near-maximal stroke volume or zero fluid balance? Brit J Anaesth 2012; 109 (2): T Corcoran et al. Perioperative Fluid Management Strategies in Major Surgery: A Stratified Meta-Analysis. Anesth Analg 2012;114: C Challand et al. Randomized Controlled Trial of Intraoperative Goal-Directed Fluid Therapy in Aerobically Fit and Unfit Patients Having Major Colorectal Surgery. British Journal of Anaesthesia 2012;108(1): MFMER slide-126

127 Additional References and Further Reading SR Walsh et al. Perioperative fluid restriction reduces complications after major gastrointestinal surgery. Surgery 2008;143(4): B Brandstrup et al. Effects of Intravenous Fluid Restriction on Postoperative Complications: Comparison of Two Perioperative Fluid Regimens, A Randomized Assessor-Blinded Multicenter Trial. Annals of Surgery 2003; 238(5). N Cregg et al. Oliguria During Corrective Spinal Surgery for Idiopathic Scoliosis: the Role of Antidiuretic Hormone. Pediatric Anesthesia 1999;9(6): MFMER slide-127

128 RIFLE Criteria for AKI/AKF R Bellomo et al, Crit Care MFMER slide-128