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 • SV ~ preload, afterload, contractility

Frank – Starling Curves

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 • 3 rd 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 – 3

rd

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

Total body water 70% of total body weight Intracellular Fluid 40% of total body weight Extracellular Fluid 20% of total body weight Interstital Fluid 15% of total body weight Plasma Volume 5% of total body weight 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 Resection

Low 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 Survival Complications Hospital stay (d)

Immediate

193 (62%) 69/227 (30%) 14

Delayed

203 (70%) 55/238 (24%) 11

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

• Regional

Effects of Anesthesia ……

transient

– Vasodilation - v enous 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. 3 rd 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 Therapy Does it make a difference?

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.m

2 /min • (eg CI=3L/min/m 2 ; 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% worsened mortality

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

3 rd 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

Clinical Studies of Hypertonic Saline • 1919 Weed and McGibben – effective in reducing ICP • 1992 Fisher – decreases ICP following head trauma in kids • 1997 Wade et al – 2 fold improved survival in adult trauma pts

Summary

• {1} Healthy pts; minimal trauma -> be generous • {2} Sicker patients; significant trauma -> be stingy In this 2 nd case –

goal directed therapy maybe helpful.

(Resp variation in sys BP, SaO2 pleth.)

My Recipe

• If you need fluid • 2 L of Ringers, then 500 ml of 3% saline • Then, consider blood products or colloid