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Cardiac Anesthesia Update. Charles E. Smith, MD Professor, CWRU School of Medicine Director, CT Anesthesia MetroHealth Medical Center. Objectives. ASE guidelines- IOTEE ACC/AHA guidelines- Valves Diabetes + hyperglycemia Neurocognitive dysfunction Transfusion. ASE/SCA Guidelines- TEE.
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Cardiac Anesthesia Update Charles E. Smith, MD Professor, CWRU School of Medicine Director, CT Anesthesia MetroHealth Medical Center
Objectives • ASE guidelines- IOTEE • ACC/AHA guidelines- Valves • Diabetes + hyperglycemia • Neurocognitive dysfunction • Transfusion
ASE/SCA Guidelines- TEE • Accelerated growth of IOTEE by anesthesia • Complexity of US technology • Conduct of exam • Interpretation of results Mathews JP et al: ASE / SCA Recommendations and Guidelines for CQI in Perioperative Echo. JASE + Anesth Analg 2006.
Training + Credentialing • 2 levels of training: basic + advanced • Basic: within usual practice of anesthesia • ventricular fct, gross valve lesions • Advanced: full diagnostic potential of echo • ASE /SCA/NBE: • Testamur status: exam • Board certified: 1 yr TEE/ CT fellowship [vs alternate training, 2-4 yr, 300 exams] • Credentialing: hospital-specific process Mathews JP et al: JASE + Anesth Analg 2006.
Standard TEE Exam: Guidelines • Comprehensive: 20 cross-sectional views • UE level: Asc aorta, MPA, L+R atria, AV+PV • ME level: L+R atria, L+R ventricles, MV+TV • TG: L+R ventricles • Thoracic Aorta: Desc + distal arch Mathews JP et al: ASE / SCA Recommendations and Guidelines for CQI in Perioperative Echo. JASE + Anesth Analg 2006.
ACC/AHA Guidelines • Review of literature by experts • Grade evidence: Level A →C [RCT→opinion] • Recommendations: • Class I: beneficial • Class IIa: generally in favor • Class IIb: less well established • Class III: not useful, potentially harmful? AAC/AHA Task Force on Practice Guidelines. Circulation 2006;114(5)e84-231. Endorsed by SCA, STS
Valvular Heart Disease • Decision to repair/replace valve should be made before surgery • IOTEE should be used to confirm dx, evaluate repair + evaluate new findings (e.g., moderate AS in setting of CABG, moderate AI if ↓ EF or ↑ LVEDD, aortic root reconstruction if dilated > 5 cm) AAC/AHA Task Force on Practice Guidelines. Circulation 2006;114(5)e84-231. Endorsed by SCA, STS
IOTEE Indications • Class I: valve repair, valve replacement- stentless / autograft (Ross), valve surgery in setting of endocarditis • Level of evidence= B • Class IIa: all valve surgeries • Level of evidence =C AAC/AHA Task Force on Practice Guidelines. Circulation 2006;114(5)e84-231. Endorsed by SCA, STS
Aortic Stenosis • Check annulus size • Verify size of aortic root (mismatch? aneurysmal?) • After bypass: problems w prosthesis: immobility, leaks AAC/AHA Task Force on Practice Guidelines. Circulation 2006;114(5)e84-231. Endorsed by SCA, STS
Severe Aortic Stenosis 2.0 cm 5.7 m/s 1.3 m/s 2.0 2 1.3 AVA = 3.14 ( ------) X ------ = 0.72 cm2 2 5.7
Severe Aortic Regurgitation T 1/2 = 84 ms Vena Contracta = 11 mm
Mitral Regurgitation Functional vs structural After bypass: Residual MR, MS, SAM Leaks Immobility of prosthesis AAC/AHA Task Force on Practice Guidelines. Circulation 2006;114(5)e84-231. Endorsed by SCA, STS
Severe Mitral Regurgitation PISA ROA rn=1.1cm vn=59 cm vp=450 cm = 2Π(1.1)2(59/450) = 0.99 cm2
Cardiac Tamponade RA Diastolic Collapse
Type A Dissection: TEE MHMC #0777095 Type A dissection with flap extending to just superior to RCA ostium
Aortic Dissection: TEE Distal Thoracic Aorta MHMC #0777095 Demonstration of extension of dissection distally
Diabetes + Hyperglycemia • neuro injury after focal + global ischemia • myocardial infarct size • WBC function • Impaired wound healing • risk infection, especially gluc > 250
Reasons for Hyperglycemia • insulin requirements w obesity, steroids, stress response to surgery + CPB • Excess glucose in pump prime, cardioplegia • gluconeogenesis + glycogen breakdown (CPB + stress response) • glucose utilization: hypothermia • insulin production: pancreatic hypoperfusion Smith et al: J Cardiothorac Vasc Anesth 2005;19:201
Diabetes + Deep Sternal Wound Infection • Hyperglycemia - major role in impaired wound healing + deep sternal wound infection • Insulin infusion + moderate control • Titrate infusion to gluc 125-175 mg/dl • Start in OR, continue to POD 3 • incidence to 0.3%, similar to non-diabetics Portland Protocol: Starr Center for Cardiac Surgery. www.starwood.com/research/insulin.html
Van Den Berge Study • RCT, 1548 diabetic + non-diabetic SICU patients • 60% had cardiac surgery • Compared tight vs. conventional glucose control • Tight: 80-110 mg/dl • Conventional: insulin only if glucose > 210; endpoint 180-200 • mortality in tight group 4.6 v. 8% • infections, dialysis dependent RF, # transfusions required, need for prolonged mechanical ventilation N Engl J Med 2001;345:1359-67
How Tight Should Intraop Control Be? • Furnary- 99: < 200 w insulin infusion ↓ mortality • Van den Berghe- 01: 80-110 w insulin infusion ↓ mortality (vs 180-220) • Furnary- 03: < 150 w insulin infusion ↓ mortality (vs > 250) • Finney- 03: < 145 • Lazar- 04: < 200 w insulin infusion (vs > 250) • Ouattata- 05: < 200 w insulin infusion
MHMC Study • Prospective, non-randomized, n=40 • Diabetics received continuous infusion regular insulin, 10 u/m2/h + variable D10W, starting rate 100 ml/h or 9.4 gm gluc/h • Target glucose 101- 140 • Standardized anesthetic, bypass, cardioplegia • POC glucose testing + multiple biochemical measurements J Cardiothorac Vasc Anesth 2005;19:201
MHMC Study- Results • 53% achieved adequate intraop control + 35% had control by end of surgery [total =88%] • 12% never had control (starting glucose 307-550) • 25% had hypoglycemia requiring D50 (mean gluc 57, range 33-74, mostly CRF pts) J Cardiothorac Vasc Anesth 2005;19:201
Current Approach- Diabetics • Insulin infusion- mix 250 units regular insulin in 250 ml 0.9% saline • Flush line w 25 ml [insulin binds to tubing] • Starting dose: gluc/100 per hr, continue in ICU • Target glucose 100 - 150 • Measure gluc q 1h • Bolus doses can be given IV • Be careful with renal failure +after CPB- accumulation of insulin + risk hypoglycemia
Cognitive Dysfunction • Inability to perform normal activities after surgery • 4 major domains of function • Verbal memory + language comprehension • Abstraction, visuo-spatial orientation • Attention, psychomotor processing speed, concentration • Visual memory Newman MF: SCA Annual Meeting, 2007
Cognitive Decline, CABG Newman MF: N Engl J Med 2001;344:395. Duke, n=261
Social + Economic Costs • Cognitive dysfunction • ↓ quality of life • ↓ return to work • Altered personality, relationships • ↓ sexual function
Implications • Abrupt decline in cognitive function heralds: • Loss of independence • Withdrawal from society • Death Seattle Longitudinal Study of Aging Berlin Aging Study
Potential Mechanisms • High-risk patients • High-risk surgical procedures • High-risk anesthetic techniques
Patient Risk Factors • Predictors:↓ baseline cognition, deficit at discharge, ↑ age, ↓ yrs of education • Not predictive: EF, HTN, DM, surgical factors: XC time, CPB time • Etiology: ASVD of proximal aorta, genetics, anesthetics, pre-existing brain disease Newman MF: SCA Annual Meeting, 2007
Genetic Factors • ApolipoproteinE ε-4 hyp: APOE allele- ↓ cognitive outcome • Single nucleotide polymorphisms: SNPs- modulate inflammation, cell matrix adhesion/interaction, lipid metabolism, vascular reactivity, PEGASUS study: • minor alleles of CRP 1059G/C + SELP 1087G/A associated w POCD Newman MF: SCA Annual Meeting, 2007
Surgical Factors: Aortic Manipulation Emboli detected by TEE after unclamping; Barbut D: 1996
Microemboli or SCADs • Small capillary + arteriolar dilations: 10-70 microns • “Footprint” of embolic material during CPB • density correlates with CPB duration • after CPB, most gone by 1 wk Moody DM: AnnThorac Surg 1995;59:1304
Anesthetic Factors • May interact w peptides- ↑ oligomerization, amyloid deposition + protein folding • Low BIS levels were associated w ↑ risk in elderly [cumulative hr BIS < 45] • Longitudinal studies in progress to assess POCD, delirium + effect of anesthetics Monk TG: Anesthesiology 2004;A62 Newman MF: SCA Annual Meeting, 2007
Anesthetic Risk Factors • Anesthetic agents affect release of CNS neurotransmitters • acetylcholine, dopamine, norepinephrine • Effects of anesthetics on cholinergic neurons in the basal forebrain [memory regulation]? • Effects of aging on choline reserves • Difficult to evaluate effects of anesthesia on long term memory + cognition
Blood Trx + Blood Conservation • Cardiac surgery consumes >80% blood products transfused at operation • Blood products may be assoc w major morbidity + mortality: TRIM, TRALI, infection, death • Trx practices vary greatly • High risk pts: Elderly, Preop anemia / coagulation defect, Preop antiplatelet drugs, Redo or complex procedure, Emergency, co-morbidities
Optimal hematocrit-1 • Therapeutic dilemma: Anemia is bad, but so is transfusion • Anemia • ↑ mortality • ↓ quality of life • Jeopardizes organ viability, especially in presence of limited vasodilator reserve Gravlee GP. SCA Annual Meeting, 2007
Optimal hematocrit- 2 • Therapeutic dilemma, cont’d • Transfusion is bad • ↑ mortality + morbidity • immediate ↑ O2 transport is limited • TRIM, ↑ inflammation [role of leukoreduction], TRALI • Viral/bacteria/parasites Gravlee GP. SCA Annual Meeting, 2007
Transfusion Avoidance Techniques • High yield: • ↑ preop Hct • ↓ CPB priming volume • RAP: retrograde autologous priming • Effective intraop cell saver • Ultrafiltration • Lower yield: • Antifibrinolytics • Protamine dosing Gravlee GP. SCA Annual Meeting, 2007
Retrograde Autologous Priming • Replace crystalloid prime w pts own blood • Limits degree of HD • Fewer pts reach critical trx trigger Murphy GS. SCA Annual Meeting, 2007