The Use of Dynamic Parameters in Perioperative Fluid Management

Transcription

1 The Use of Dynamic Parameters in Perioperative Fluid Management Gerard R. Manecke Jr., M.D. Chief, Cardiac Anesthesia UCSD Medical Center San Diego, CA, USA Thanks to Tom Higgins, M.D. 1

2 Goals of today s lecture: History overview of perioperative fluid management Make the case for more aggressive perioperative management (GDT) Discuss Dynamic Parameters Case presentation The Four Approaches to Perioperative Fluid Management 1. Don t worry about it. 2. Make assumptions and give a lot Rule for maintenance Rule for 3rd Space and insensible 3:1 crystalloid replacement for blood loss 3. Make assumptions and restrict 4 ml/kg/hr 4. Goal Directed Therapy Hemodynamic Oxygen Delivery 2

3 Don t Worry About it A single nephron is smarter than the smartest anesthesiologist Annals of Surgery, Vol 119, No. 4. P , s: Salt is bad for surgical patients. Do not give any salt. If you must give fluid, give Dextrose in water 3

4 1950s: Surgical patients seem to require salt and fluid, probably because of 3rd space and other losses Annals of Surgery, Volume 154, , 1961 Make assumptions and Give a lot (4-6-8 ml/kg/hr crystalloid) Mass General Handbook Barash, 5th edition Miller, 5th edition Miller and Stoelting, 5th edition 4

5 Stoelting and Miller, 5th edition, s: Maybe giving a lot of fluid (particularly crystalloid) is bad 5

6 Fluid overload problems Heart Lung Bowel Airway Skin Vision Relationship with surgeon Maybe we should restrict fluids (make assumptions and give little) Annals of Surgery Volume 238, Number 5, November

7 Inescapable Conclusions: Too much fluid (water) is bad Edema Not enough fluid is bad Inadequate tissue perfusion Assumptions often invalid Fluid management should be individualized Goal Directed Therapy: using more patient data and fewer assumptions 7

8 Goal Directed Therapy: what data? SV, CO Dynamic parameters (SVV, PPV) Central venous oxygenation Tissue blood Flow Tissue oxygenation Hypothesis:Immediate aggressive Tx of Septic Patients during the GOLDEN HOURS IMPROVED OUTCOME 263 Patients with sepsis, treated in ER Randomized, blinded in later(icu) course Two groups: Goal Directed (venous O2 as CO surrogate) Standard Therapy 8

9 ScvO2>70% Hct >30 MAP >65 CVP 8-12 Urine Output>0.5ml/kg/hr Treatment group Lower Mortality In Hospital: 50% vs 38% (P=0.009) 28 day: 61% vs 40% (P=0.01) 60 day: 70% vs 50% (P=0.03) 9

10 Conclusions: Early, aggressive intervention in septic patients improves outcome and decreases utilization of resources 100 Surgical Patients (anticipated blood loss>500ml Randomized 50 standard therapy 50 GDT Plasma Volume Expansion Esophageal Doppler: Stroke Volume Measurements: Morbidity, Mortality Length of stay, bowel function, renal function Nausea, Vomiting 10

11 Methods Goal Directed Therapy Group Corrected Flow Time (FTc) and SV maximized using hetastarch, LR. Control Group Fluid administration guided by Urine Output Heart Rate Blood Pressure Results Severe PONV less in Goal Directed Group: 14% vs 36% (P<0.05) LOS less in Goal Directed Group:5 days vs 7 days (P=0.04) 11

12 Conclusions LOS related to return of GI function Hypovolemia associated with poor postop GI Function Gut hypoperfusion Early volume goal directed therapy improves outcome Length of stay Nausea and Vomiting Critical Care 2005, 9:R687-R693 BMJ 1997, 315:

13 Optimizing Tissue O2 IntraOp Timing Critical! Better Postoperative Recovery Shorter LOS Cost benefit Patient Benefit Dynamic Parameters: Ventilation results in Systolic Pressure Variation (Perel) Pulse Pressure Variation (Pinsky, Michard) Stroke Volume Variation 13

14 Muscle Physiology Acme Stimulator off fry contraction kg Weight (Preload) c T Higgins LV Output (SV, CO, BP) Frank-Starling Curve Effect of increasing Preload Normal Contractility LV Filling (LVEDV, LVEDP, PAOP, CVP) 14

15 Frank-Starling Curve LV Output (SV, CO, BP) Not all curves are equal Normal Contractility Failing Heart LV Filling (LVEDV, LVEDP, PAOP, CVP) LV Output (SV, CO, BP) Low Output (SV) can be interpreted two ways: 1)Patient is empty (Low Preload) Normal Contractility filling the tank will improve output start volume Failing Heart LV Filling (LVEDV, LVEDP, PAOP, CVP) 15

16 Low Output (SV) can be interpreted two ways: LV Output (SV, CO, BP) 1)Patient is empty (Low Preload) 2)Patient has a failing heart Normal Contractility little or no response to additional volume start Failing Heart LV Filling (LVEDV, LVEDP, PAOP, CVP) LV Output (SV, CO, PP, BP) Magnitude of PPV/SVV related to LV filling (volume) EMPTY FULL Effects of changing Airway pressure LV Filling (LVEDV, LVEDP, PAOP, CVP) c T. Higgins 16

17 PPV with Mechanical Ventilation PAW PArt a time b PPV = (b a) / mean Stroke Volume Variation 17

18 Pulsus Paradoxus In normal individuals, the systolic blood pressure drops 5-10 mmhg upon inspiration. Filling impediments to either ventricle may exaggerate this, with drop in BP>10 mmhg upon inspiration (PULSUS PARADOXUS) Pulsus Paradoxus caused by filling impediment to either ventricle Hypovolemia Constrictive Pericarditis Cardiac Tamponade Asthma Attack 18

19 SVV (Stroke Volume Variation) is the inverse of Pulsus Paradoxus, when patient receives Positive Pressure Ventilation Stroke Volume Variation Pulse Pressure Variation 19

20 MECHANISM OF SVV Positive Pressure Breath Intrathoracic Pressure RV Afterload RV Preload LV Preload Acute SV Empty Pulmonary Venous System Delayed SV Stroke Volume Variation predicts fluid responsiveness more effectively than: PCWP CVP Cardiac Output Intrathoracic Blood Volume Urine output Serum lactate, ph Cardiac End Diastolic Volume 20

21 Stroke Volume Variation (SVV = SV max-sv min/sv mean) SV full SVV <10% empty SVV >13% Equal change In filling w/ breaths Filling Pressure (LVEDV, PCWP, CVP, etc.) c T. Higgins Effect of Volume Expansion on D Pulse Pressure (SVV) 500 cc hetastarch max min Baseline VE DPP: 27% DPP: 9% Jardin & Vieillard-Baron. Intensive Care Med 29: ,

22 Does Pulse Pressure Variation Predict Preload Responsiveness? HD Measurements performed in duplicate in 40 septic hypotensive patients: PPV, SPV, PAOP, RAP, CO Prior to volume expansion 30 minutes after volume expansion (500 ml 6% Hetastarch) Paralyzed mechanically ventilated Michard et al. Am J Respir Crit Care Med 162: Baseline D PP Predicts Volume Responsiveness in Hypotensive Septic Patients Michard et al. Am J Respir Crit Care Med 162:

23 Receiver-Operating Characteristic (ROC) Curve Adapted from Swets: Measuring the Accuracy of Diagnostic Systems Science 1988: 240: True-positive proportion 1 minus sensitivity 0% False-positive proportion 100% Receiver-Operating Characteristic (ROC) Curve 100% COIN FLIP: True-positive proportion specificity 100% (True +) = (False -) ROC = % False-positive proportion 100% 23

24 Receiver-Operating Characteristic (ROC) Curve 100% True-positive proportion SLIGHTLY BETTER TEST (True +) > (False -) ROC = % False-positive proportion 100% Receiver-Operating Characteristic (ROC) Curve True-positive proportion 100% GOOD TEST (True +) >> (False -) ROC = % False-positive proportion 100% 24

25 Receiver-Operator Characteristic (ROC) Curve for Predicting >15% Increase in Cardiac Output Excellent: good AUC=0.98 PPV(13%) Sens 94% Spec 96% True + worthless True + False + Michard et al. Am J Respir Crit Care Med 162: Why? Pressure is not volume Only dynamic parameters such as SVV, PPV can tell you where the heart is on its Starling Curve!! 25

26 SVV/PPV seems interesting, but is it merely academic? What is the future of SVV? SVV is not going away 26

27 A 78 year old man for endovascular abdominal aortic aneurysm repair Hypertension, atherosclerotic heart disease General Anesthesia, positive pressure ventilation Arterial line (APCO), peripheral IV (2) Femoral artery cannulated, procedure for stent placement Femoral region draped with towels A 78 year old man for endovascular abdominal aortic aneurysm repair One liter of crystalloid over first hour BP 136/78, HR 64 Cardiac Output 4.5 L/min Stroke Volume Variation 7% Hct=38 Pulse oximeter O2 sat=99% 27

28 One hour into surgery Cardiac output drops to 3.1 L/min SVV to 35% BP 110/60 HR to 76 BPM diagnosis? Hypovolemia Aortic or other great vessel trauma? Other source of volume loss? 28

29 Three units of packed red blood cells, 500 ml 5% albumin, 500 ml crystalloid administered Cardiac Output returned to baseline (4.5 L/min) SVV returned to <10% HR came back down to the 60s Surgeons were nice to us for the rest of the day Lessons learned APCO facilitated the rapid diagnosis of hypovolemia with cardiovascular compromise TITRATION OF TREATMENT: Cardiac output and SVV information allowed rapid fluid resuscitation without overshoot in an elderly, frail patient 29

30 Thank You! 30