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Perioperative Fluid Management. Fred Rotenberg, MD January 10, 2007. Goals of Fluid Administration. O2 delivery / blood flow - perfusion Maintain electrolyte composition, Glycemia, Body temperature. O2 Delivery. DO2~ Q x CaO2 CaO2 ~ SaO2, CO, Hgb CO ~ SV x HR
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Perioperative FluidManagement Fred Rotenberg, MD January 10, 2007
Goals of Fluid Administration • O2 delivery / blood flow - perfusion • Maintain electrolyte composition, • Glycemia, • Body temperature
O2 Delivery • DO2~ Q x CaO2 • CaO2 ~ SaO2, CO, Hgb • CO ~ SV x HR • SV ~ preload, afterload, contractility
Maximizing CO Frank – Starling Curves • Slope of curve is EF • “Good” ventricles are preload dependent • “Poor” ventricles are afterload dependent – (not preload dependent)
For Low SV / CO • Good LV function -> give fluid • Poor LV function -> Inotropes • Vasodilators • Diuretics
How much to give and when to give it IT DEPENDS- Type of patient Type of surgery Amount of trauma Acute injury vs. elective Anesthetic, positioning Who you listen to
“Classic” fluid management • Deficits • Maintenance • 3rd Space • Blood loss
Deficits • Estimate • Preop NPO (hourly maintenance x duration) • Preop bowel preparation (1-1.5L) • Preop blood loss (trauma) or fluid loss (burns) Typically replaced over first 2-4 hours
Maintenance • (4-2-1 rule) • 4 ml/kg/hr for first 10 kg of body weight • 2 ml/kg/hr for 2nd 10 kg of body weight • 1 ml/kg/hr for each kg of body weight above 20 kg • Based on water loss from burning calories • from Holliday and Segar
Replace fluid losses • “Third space” 2-10 ml/kg/hr • Blood losses: • 3 to 1 ratio of crystalloid to EBL • 1 to 1 for colloid or blood • (or hypertonic saline)
Surgical Trauma: Third Spacing • Capillary and Endothelial injury; leak • Sequestration of fluid into tissues • i.e. TRAUMA causes FLUID Retention Creation of nonfunctional component of ISF • Return of fluid from this ‘third space’ 1-4 days after surgery
Surgical Trauma – 3rd space • Shires: Annals of Surgery 1961 • Minor (< 200cc EBL) vs Major (>200cc EBL) • No fluids administered for at least 2 hours • Measured Functional Extracellular Fluid • Minor Surgery had minimal changes in ECF; 1.4% • Major Surgery had 0-28% changes in ECF • Conclusions • Change in ECF secondary to redistribution • Change not related to blood loss • Change correlate with amount of trauma to tissues • Retractors and manipulation
Distribution of Fluid 3RD SPACE
Healthy outpatients – minor procedure • 1 vs 2 liters of fluid • Decrease thirst, dizziness, drowsiness pain and nausea • Reduce time til discharge • May improve respiratory function post operatively
Outpatient ASA I-II for Lap CCY • More generous fluids (15 vs 40 ml/kg for the case) • Improved post op pulmonary fxn • Improved exercise tolerance • Improve nausea, “well being”, dizziness, drowsiness, fatigue, balance • Holte et al. Ann Surg 2004
Risks of Excess Fluids • Interstitial edema • Impaired cellular metabolism • Poor wound healing • Decreased pulmonary compliance • Heart failure – overload • Delayed return of bowel function • Hemodilution
Specific Scenarios • Postoperative weight gain • Pulmonary surgery • Hepatic surgery • Vascular surgery • Hip surgery • Trauma • Neurotrauma
Postoperative Weight Gain • Lowell et al CCM 1990 • 48 patients admitted to SICU • 40% of patients had > 10% weight gain • Weight gain related to: • Mortality • RBC transfusion • FFP transfusion • Mechanical Ventilation When matched to controls, fluid administration was significant variable
Restricted fluids in Intra-abdominal Surgery • Restricted = 4 ml/kg/hr (e.g. 850ml) vs. • Liberal = 10 ml/kg bolus + 12 ml/kg/hr (e.g. 3200) • Earlier bowel function and hospital discharge, less weight gain with restriction • Nisanevich et al. Anesth 2005
Pulmonary Surgery • Miller et al: Annals Thoracic Surg 2002 • 115 completion pneumonectomies • PPE occurred in 15% with Mortality of 43% • Mortality related to Fluid administration 12 hours 1800 vs 2500 24 hours 2300 vs 2800
Hemodilution: Cardiac Effects • Mangano NEJM 1991, JACC 1991: • 83/474 cardiac events (17%) noncardiac surgery • 30/84 CHF (35%) • 1-3 days postop; vascular patients more frequent • Speculation: related to greater fluid administration to patients at risk • Nelson CCM 1993: vascular surgical patients • Worse outcome with Hct < 28% • Speculation: Due to hemodilution • Spahn JTCVS 1993: 19 dogs with acute LAD occlusion • Ischemia with hemodilution to Hgb 7.5 gm/dl • Baron Anesth 1987 • Epidural dosing and fluid loading (500 cc) in patients with WMA • Mangano Circ 1980 and Dehert Anesth 1999 • Impaired contractile response to fluid bolus (500-1500) or leg elevation when compared to Phenylephrine
Hepatic ResectionLow CVP Technique • Melendez et al J Am Coll Surg 1998 • Low CVP technique: 496 resections • IVF 1 cc/kg/hr and boluses as needed • NTG, dopamine, mannitol as needed • Urine output > 25 cc/hr • SBP > 90 mmHg • CVP < 5 mmHg • Results • Reduction in EBL and transfusion • One patient with renal failure due to aminoglycoside • Improved visualization of surgical field • Reduces pressure in hepatic tissues
Hip Replacement • Sharrock: Br J Anaesth; Reg Anesth • 987 surgeries • Spinal/Epidural hypotension (mBP 50-55mmHg) • Fluid restriction to minimize perioperative CHF • Epinephrine as needed to maintain BP and CO • Improved Outcome • 2 myocardial infarction • Reduction in EBL and transfusions compared to controls • 0 renal failures • 3 deaths (0.4%)
Trauma – “Scoop and Run” • Bickell: NEJM 1994 • 598 penetrating torso injuries: pre SBP < 90 mmHg • Immediate (309) vs Delayed (298) fluid resuscitation • Outcome • Preop Fluid: 2500cc vs 350cc • Less periop blood transfused: 2070cc vs 1720cc • Improved pulmonary function • Decreased mortality
WHAT’S DIFFERENT BETWEEN OUTPT AND INPT? • I.E. THE PREOP CONDITION OF THE PT • THE EXTENT OF TRAUMA (AND 3RD SPACE LOSS) • THE ABILITY TO HANDLE FLUIDS • THE ANESTHETIC EFFECTS
Effects of Anesthesia……transient • Regional • Vasodilation - venous pooling • General • Myocardial depressants • Vasodilation • Reductions in natriuretic hormone • Increase in Anti-diuretic hormone • Mechanical Ventilation • Decrease in venous return • FLUID ELIMINATION IS GREATER POST-OP • BUT THE RATE OF ELIMINATION IS NOT RELATED TO AMT OF FLUID ADMINISTERED
Isoflurane • Promotes extravascular fluid accumulation during crystalloid loading (i.e. 3rd space loss) • Not related to mechanical ventilation • Is this due to increased ADH, ANP? • Reduces GFR by 30-50% • Renal blood flow by 40-60% • Urine output by 65%
Fluids? Drugs? Both? • Volume status? HX; PE; LABS • I.E. What is hypovolemia? - Check neck veins, urine volume and color • Labile blood pressure suggests hypovolemia • The “Rotenberg Rule” – when the HR is higher than the systolic BP -> give fluid • Respiratory variation in BP or pulse ox pleth
Monitors • Skin color, reperfusion, mucous membranes, weight change • HR, BP (systolic pressure variation) • I’s/O’s; Fluid Administration, Urine output, Blood loss • ETCO2; PaCO2-ETCO2 • CVP, PAP, PCWP, CO, MvO2 • TEE – Doppler CO measurements
Arterial vs Plethysmographic Dynamic Indices for Testing Fluid Administration in Hypotensive Patients • Only ½ of hypotensive pts increase CO s/p fluid challenge • BP and plethysmographic variation w/ PPV predicts responsiveness to fluids • Anes Anal 103:1478 (Dec’06)
ART BP SaO2 PLETH
Predicting response to fluids • ?Baseline BP - X • ? Baseline HR - X • ? Baseline Filling pressures - X • Baseline CI ! • ?Respiratory variation of BP or SaO2 pleth • Response to fluid loading of the above !
Goal directed fluid therapy • Hemodynamics / systolic pressure variation • CVP / PCWP • Cardiac output / SV • O2 delivery (CO plus SaO2) • Fluids plus inotropes -
Fluids plus Inotropes • Pushing O2 delivery > 600ml O2.m2/min • (eg CI=3L/min/m2; HgB=14; SaO2=98) • May decrease mortality and morbidity • Dopexamine better than Epi • Aggressive management should be instituted early
Guided Fluid administration • Relatively small increase in fluids given (i.e. 200- 500 ml using CVP; 1 L using PA) • May reduce post op renal insufficiency • No major benefit as long as central hemodynamics are maintained * • Using DOPPLER - May provide quicker return of bowel function and hospital discharge; less complications • No improvement in mortality
Timing of fluids • Preop fluids retained shorter than intra-op fluids • I.e. Surgical fluids are retained • Scoop and run vs. early fluid administration
Choice of fluids • Crystalloids • Colloids • Blood products • Whole blood • PRBC • FFP • Platelets
Colloids do not improve outcome • Meta-analysis showed a 12.3% worsenedmortality with colloids in multiple trauma • Saline solutions may produce hyperchloremic acidosis
Colloids and Renal Dysfunction • The dehydrated patient who receives considerable amounts of (hyperoncotic) colloids is especially at risk for developing ARF. It may be advisable to administer colloid in addition to, rather than in lieu of, crystalloids. Boldt & Priebe, A and A 2003
3rd space Interstitial fluid
Hypertonic (hyperosmolar) solutions • Temporarily shifts water from intracellular and interstitial space to intravascular space • Reduces CSF secretion rate
Limit volume of Hypertonic Saline • 1 liter of 3% max • Too much 3% may • Cause rebound intracranial hypertension • Cause hyperchloremic acidosis, hypokalemia • Cause intracellular dehydration • Hyperchloremia may cause renal vasoconstriction
Clinical Studies of Hypertonic Saline • Efficacious for hypotensive brain injured pts in transfer to hospital • Lesser amount of cerebral edema • May reduce ICP where mannitol has failed • Improves CO /reduces SVR better than LR • Promotes diuresis, reduces edema • Increased serum sodium (to ~150’s) is well tolerated