cardiac anesthesia update charles e. smith, md professor, cwru school of medicine director, ct...

Cardiac Anesthesia Update

Charles E. Smith, MD

Professor, CWRU School of Medicine

Director, CT Anesthesia

MetroHealth Medical Center

Objectives

1. ASE guidelines- IOTEE

2. ACC/AHA guidelines- Valves

3. Diabetes + hyperglycemia

4. Neurocognitive dysfunction

5. 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 archMathews JP et al: ASE / SCA Recommendations and Guidelines for CQI in Perioperative Echo. JASE + Anesth Analg 2006.

Transgastric view: L+R ventricles

ME views: L+R atria, L+R ventricles, MV+TV

UE views: Asc aorta, MPA, L+R atria, AV+PV, pulm veins

Thoracic Aorta: prox asc aorta, distal arch, descending

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)


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


Aortic Stenosis

• Check annulus size

• Verify size of aortic root (mismatch? aneurysmal?)

• After bypass: problems w prosthesis: immobility, leaks


Severe Aortic Stenosis

5.7 m/s

2.0 cm

1.3 m/s 2.0 2 1.3AVA = 3.14 ( ------) X ------ = 0.72 cm2

2 5.7

Severe Aortic RegurgitationT 1/2 = 84 msT 1/2 = 84 ms

Vena Contracta = 11 mmVena Contracta = 11 mm

Mitral Regurgitation


Functional vs structural

After bypass:

Residual MR, MS, SAM

Leaks

Immobility of prosthesis

Severe Mitral Regurgitation

PISA ROAPISA ROA

rrnn=1.1cm=1.1cm

vvnn=59 cm=59 cm

vvpp=450 cm=450 cm

= 2= 2ΠΠ(1.1)(1.1)22(59/450)(59/450)= 0.99 cm= 0.99 cm22

MR QuantitationMild Severe

Jet Area (cm2) <4; <20% LA ≥40% LA

VC (cm) <0.3 >0.6

RV (cc/beat) <30 ≥60

RF (%) <30 ≥50

ERO (cm2) <0.2 ≥0.4

Pulm vein flow

Blunted systolic Systolic reversal

LA size N or dilated 1+ Dilated +++

Outflow Tract Obstruction

Cardiac Tamponade

RA Diastolic CollapseRA Diastolic Collapse

Type A Dissection: TEE

MHMC #0777095

Type A dissection with flap extending to just superior to RCA ostium

Aortic Dissection:

MHMC #0777095

Demonstration of extension of dissection distally

TEE Distal Thoracic Aorta

Diabetes + Hyperglycemia

neuro injury after focal + global ischemia myocardial infarct size WBC function

• Impaired wound healing risk infection, especially gluc > 250

Reasons for Hyperglycemia

1. insulin requirements w obesity, steroids, stress response to surgery + CPB

2. Excess glucose in pump prime, cardioplegia

3. gluconeogenesis + glycogen breakdown (CPB + stress response)

4. glucose utilization: hypothermia

5. insulin production: pancreatic hypoperfusion

Smith et al: J Cardiothorac Vasc Anesth 2005;19:201

Portland Protocol: Starr Center for Cardiac Surgery. www.starwood.com/research/insulin.html

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

N Engl J Med 2001;345:1359-67

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

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

Smith et al: 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 function1. Verbal memory + language comprehension2. Abstraction, visuo-spatial orientation3. Attention, psychomotor processing speed,

concentration4. Visual memory

Newman MF: SCA Annual Meeting, 2007

Newman MF: N Engl J Med 2001;344:395. Duke, n=261

Cognitive Decline, CABG

0

25

50

75

Discharge 6 weeks 6 months 5 years

%

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 AgingBerlin Aging Study

Potential Mechanisms1. High-risk patients2. High-risk surgical procedures3. 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


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


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;A62Newman MF: SCA Annual Meeting, 2007

Hyperthermia + POCD

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


Transfusion Avoidance Techniques

• High yield: – ↑ preop Hct

– ↓ CPB priming volume

– RAP: retrograde autologous priming

– Effective intraop cell saver

– Ultrafiltration

• Lower yield: – Antifibrinolytics

– Protamine dosing


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

Retrograde Autologous Priming- 2

• How to do this?– Heparinize, place arterial cannula, allow pts

blood to flow backwards + displace crystalloid [perfusionist: “rapping”]

– Maintain SBP > 100 using small doses of PHE (80-400 ug). Turn off vasodilators

– Primary risk- hypotension

Murphy GS. SCA Annual Meeting, 2007

Retrograde Autologous Priming-3

• What is the data?1. Rosengart, 98: ↑ Hct, ↓ RBC trx

2. Shapira, 98: ↑ Hct, ↓ RBC trx

3. Balachandran, 02: ↑ Hct, ↓ RBC trx

4. Eising, 03: ↑ COP, ↓ extravascular lung water+ earlier time to mobilization

5. Murphy, 04 + 06: ↑ Hct, trend to ↓ mortality, delirium, afib, + vent > 24 hr

Cell Salvage- 1• After bypass: transfer blood from prime to cell

saver bowl for washing• Can also collect shed blood for washing• Hct of processed blood: 60%, 2-3 DPG but

processing eliminates platelets +factors• Savings: ~ 1-2 units allogeneic blood

Cell Salvage- 2

• Requirements: CPB– Anticoagulated blood

– Centrifuge bowl + tubing

• Shed Blood– Aspiration assembly

– Reservoir

– Tubing

Cell Salvage- 3 – Few disadvantages in heart room because have:– Dedicated perfusionist + heparinized pump

prime and– Wound is clean– Risks:– Air embolism w infusion under pressure– DIC if use “cell saver suction” for

thrombogenic material

Ultrafiltration

• Remove water + low MW substances under a hydrostatic pressure gradient

• Induces hemoconcentration: ↓ total body water accumulation + inflammatory mediators

• ↓ bleeding, blood trx, morbidity + mortality

• Initially validated in peds, but also adults

Tassani 99; Kiziltepe 01; Leyh 01; Luciani 01;

Reasons Why Trx Avoidance Techniques Fail

• Had PVCs, PACS

• Had to start vasopressors/ inotropes

• Looked a little oozy

• BP a little low

• CI was a little low

• Pt was old

• Pt was high risk


Summary

1. IOTEE: routinely use for valves, often helpful for CABG

2. Hyperglycemia: treated w insulin infusion, target glucose < 150, especially if diabetic

3. Cognitive dysfunction: high risk pts + surgery; genetics + anesthetic factors play a role

4. Multimodal blood conservation techniques work well: RAP, cell saver, ultrafiltration, amicar, protamine dosing

cardiac anesthesia update charles e. smith, md professor, cwru school of medicine director, ct...

Documents