Cardiac Considerations Post MI

Preview:

Citation preview

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 1/102

Noncardiovascular Surgery for the

Cardiac Patient

Wayne E. Ellis, Ph.D., CRNA

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 2/102

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 3/102

9/19/2013 WE Ellis 4

Preoperative Assessment

• History

• Physical exam

• Laboratory findings and other

tests

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 4/102

9/19/2013 WE Ellis 5

History - Do a good one!!!

• Stability of angina

 – NYHA

• Class I: Mild angina without impairment

• Class IV: Angina at rest

 – Exercise tolerance!

 – Ventricular function

 – Associated cardiovascular diseases

 – Medication

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 5/102

9/19/2013 WE Ellis 6

Recent Myocardial Infarction

Less than three months

Patient < 70 years of age

Location of surgery

Duration of surgery

Poor LV function

CHF

Enlarged heartArrhythmias

Increased risk of morbidity and MORTALITY

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 6/102

9/19/2013 WE Ellis 7

Perioperative Predictors

Recent MI

< 6 months

Current CHFOnly consistent predictors of 

perioperative outcome

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 7/102

9/19/2013 WE Ellis 14

Challenge of anesthesia

Adequately evaluate the patient

Provide adequate anesthesia

Prevent myocardial injury

Maximize postoperative pain management

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 8/102

9/19/2013

RISK FACTORS

• genetic predisposition

• age

•gender

• obesity

• hyperlipedemia

diabetes mellitus• hypertension

• stress, tobacco, and smoking

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 9/102

9/19/2013

Smoking

• Increases the risk of an initial cardiac event

and doubles the rate of subsequent infarction

and death.

• Risk rapidly declines after stopping and by 3

years reaches that of survivors who have

never smoked.

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 10/102

9/19/2013 WE Ellis 17

Assessment of risk factors

Cigarette smoking

HypertensionDiabetes

Family history

May have a normal physical

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 11/102

9/19/2013 WE Ellis 18

Perioperative estimation of cardiac risk

Recent preoperative MI

average 8% reinfarction if within 3 months

Optimal preparation

Invasive Monitoring

Without monitoring

> 30%

Age

> 7010 fold increased risk

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 12/102

9/19/2013

Coronary Artery Disease

• Most common cause of premature death for males

between 35-45years of age.

• Each year 1.5 million MI’s occur in the U.S. 

• 280,000 OHS every year in the U.S.• $60 billion spent annually to treat CAD

• OHS represents 80% of the total adult operations

performed at most medical centers in the U.S.

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 13/102

9/19/2013

Atheroscelerosis

• begins as crystals of cholesterol adheres to

the intima.

• These crystals then form a larger matrix that

stimulates surrounding fibrous and smooth

muscle tissue growth to create additional

layers i.e.) larger plaques can grow

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 14/102

9/19/2013

Atheroscelerosis

• Larger plaques then develop into total obstructive

lesions, resulting in sclerosis(fibrosis)

• Atherosclerosis lesions become symptomatic with 75%

stenosis of one or more coronary vessels = ischemia,which depresses the myocardial function, causes chest

pain (angina pectoris).

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 15/102

9/19/2013

CAD

• Modulated by 3 factors

 – 1) Myocardial oxygen demand

 – 2) Myocardial oxygen supply

 – 3) Coronary blood flow

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 16/102

9/19/2013

Myocardial Oxygen Demand (MvO2)

• Heart extracts more 02 than any other organ, 50-70% at

rest

• BP and HR provides a basic guideline for Mv02• contractility and myocardial wall tension are primary

determinants of Mv02

• wall tension can be lowered by decreasing preload

• contractility can be lowered by beta blockers or pain

management relief 

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 17/102

9/19/2013 WE Ellis 24

Determinants of Oxygen Supply

Degree of muscular contractility

Frank Startling PrincipleThe more stretch placed on a muscle fiber

before contraction, the more forceful the

contraction.

Ventricular preload

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 18/102

9/19/2013 WE Ellis 25

Wall tension of the left ventricle

Afterload

With increased resistanceHypertrophy

Increased muscle mass

Maintain normal wall tension

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 19/102

9/19/2013 WE Ellis 26

Heart rate

The faster the rate the more oxygen required

The faster the rate there is less time for tissueoxygenation

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 20/102

9/19/2013

Myocardial Oxygen Supply

• Any increase in myocardial oxygen

requirements can be met only by raising

coronary blood flow

• Maintaing the bloods oxygen carrying

capacity is the secondary objective for

cardiovascular perfusion

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 21/102

9/19/2013

Myocardial Oxygen Supply

• Oxygen content = Ca02

• CaO2 = (hgb x 1.34) x Sa02 + (Pa02 x 0.0003)

1.34 = milliliters of 02 per gm of hgb• Sa02 = % of oxyhemoglobin of total

hemoglobin(fractional saturation)

0.003 = oxygen solubility in plasma

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 22/102

9/19/2013 WE Ellis 29

Influences affecting oxygen supply

Coronary blood flow

Left ventricle during diastole

With increased heart rate diastole is shortened

Coronary perfusion pressure

Diastolic pressure minus left ventricular end

diastolic pressure

CPP = DP-LVEDP

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 23/102

9/19/2013 WE Ellis 30

Oxygen Supply

With coronary stenosis

Improve CPP

Increase systemic pressure

Lower elevated LVEDP

Nitroglycerin

Hgb Level

Oxygen saturation

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 24/102

9/19/2013

Myocardial Oxygen Supply

• Any increase in myocardial oxygen

requirements can be met only by raising

coronary blood flow

• Maintaing the bloods oxygen carrying

capacity is the secondary objective for

cardiovascular perfusion

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 25/102

9/19/2013

Coronary blood flow

• Perfusion of the left ventricle takes place

almost entirely during diastole, whereas the

right ventricle occurs mostly with systole.

• Not only is diastole important, but the length

of diastole is critical in determining the

volume of left ventricular subendocardial

flow

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 26/102

9/19/2013

Coronary blood flow

• Coronary perfusion psi = aortic diastolic

pressure(AoDp) - LVEDP

• Note hypotension is more likely to produce

ischemia than hypertension

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 27/102

9/19/2013 WE Ellis 34

Temperature

Keep warm

Decreasing temperatureShift Oxygen dissociation curve to left

Hgb retains oxygen at tissue level

Prevent alkalosis

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 28/102

9/19/2013 WE Ellis 35

Evaluation

Select patients at highest risk of difficulty

Reinfarction in 1st 6 months post MI high

High fatality rateCABG or Angioplasty first

Choice of monitoring

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 29/102

9/19/2013 WE Ellis 36

Physical exam: Not a lot here

• Vital signs

• Cardiac exam

 – PMI

 – Gallops

• S4: HTN, S3: increased LVEDP

 – Apical systolic murmur

• Papillary muscle dysfunction

 – Precordial bulge

 – Other signs of LV function

• JVD, pulmonary signs

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 30/102

9/19/2013 WE Ellis 37

Physical Examination

Cardiovascular

JVD

Carotid Bruits

Murmurs

S3, S4, Click, Rub

Pitting Edema

Pulses

Vascular Access

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 31/102

9/19/2013 WE Ellis 38

Physical Examination

Pulmonary

Wheezes

Rales

Rhonchi

A-P Diameter

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 32/102

9/19/2013

ECG

• How many msec after the J point??

• How many mm??

• A resting 12 lead is not a whole lot of good for detecting ischemia

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 33/102

9/19/2013

Chest X-Ray

• Cardiomegaly

• Signs of ventricular dysfunction

 – Edema, effusions

• Complicating diseases

 – Calcification of vessels, valves

 – Pulmonary disease

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 34/102

9/19/2013

Blood tests

• CK, other cardiac enzymes

 – R/O after surgery: Usually an MB of about 5-

7% of total CK

• Triponin >7 positive

• Associated diseases

 – Diabetes, thyroid disease

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 35/102

9/19/2013

Primary Treatment

• Antiplatelet agents(abciximab,eptifibatide, tirofiban,

integullin)

GPIIb-IIIa antagonists• inhibit platelet function by blocking the GPIIb-IIIa

receptor, the final pathway of platelet aggregation

• thereby decreasing thrombi development and prevents

arterial vessel occlusion

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 36/102

9/19/2013

Percutaneous Coronary Intervention

• Advantages include: higher recanulazation

rates

• improved blood flow through the infarct-

related vessel

• improved LV function

• lower in-hospital mortality rates

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 37/102

9/19/2013 WE Ellis 46

Normal Hemodynamic Measurements

RA (mean)

RV (mean)

PA (sys/dys)LA or wedge (mean)

LV (sys/dys)

Systemic arterial (sys/dys)

2 - 8

15 - 30/2 - 8

15 - 30/4 - 122 - 10

100 - 140/3 - 12

100 - 140/60 - 90

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 38/102

9/19/2013 WE Ellis 47

Monitoring

Routine

Pulse Oximetry

PNS

Capnography

Temperature

Core and peripheral

ECGLeads V5 and II

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 39/102

9/19/2013 WE Ellis 48

Monitors of Cardiac Performance

Arterial Line

Standard of Care

Site selection

Pulmonary Artery Catheter

Provides means for assessing filling pressures

Reliable site for drug administration

Transesophageal Echocardiography

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 40/102

9/19/2013 WE Ellis 51

Physical signs

Jugular distentionChest sounds

Rales

Extra heart sounds

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 41/102

9/19/2013 WE Ellis 58

Preoperative Evaluation

History

Physical assessment

EKG evaluation

Exercise tolerance

Chest X-ray

Lab studies

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 42/102

9/19/2013 WE Ellis 59

Preoperative Evaluation

Current Medication

Beta-blockers

Calcium Channel Blockers

Antidysrhythmia agents

Nitrates

Diuretics

Antihypertensive agents

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 43/102

9/19/2013 WE Ellis 60

Dyspnea

Activity

Rest

What starts it

How long lasts

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 44/102

9/19/2013 WE Ellis 73

Dynamic Predictors

Acute imbalances in myocardial oxygen supply and

demand may produce ischemia that may result in

irreversible cardiac morbidity

HypertensionHypotension

Tachycardia

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 45/102

9/19/2013 WE Ellis 74

Dynamic Predictors

Hypertension

No conclusive correlation

Intraoperative Hypertension

MI

Acute Hypertension

Precedes intraoperative ischemic events

50% of time

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 46/102

9/19/2013 WE Ellis 75

Dynamic Predictors

Hypotension

25 % of ischemic events associated with > 20 % decrease in

systolic blood pressure

6 % decrease in MAP

Important predictor of PCM

Higher reinfarction rate

15.2 % vs. 3.2 %

Intraoperative hypotension

> 30% decrease in systolic BP

> 10 minutes duration

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 47/102

9/19/2013 WE Ellis 76

Dynamic Predictors

TachycardiaCombination with hypotension

Ominous

Significant indicator of PCM

Myocardial Ischemia

ST changesNot a clear indicator of PCM

TEE

Most sensitive, earlier indices of ischemia

Before ST segment changes

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 48/102

9/19/2013

Treatment of ischemia

• Is it real?

• Optimize oxygenation and hemodynamics

• IV NTG

• SL Nifedipine• Diltiazem

• Intra-aortic Ballon Pump

 – Improves systolic run off 

 – Provides diastolic augmentation

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 49/102

9/19/2013 WE Ellis 78

Anesthesia Goals

Balance supply and demandControl heart rate

Normal to slow range

Maintain CPP

Prevent hypotension

Prevent increased LVEDP

Optimize arterial oxygen and carbon dioxide

statusKeep patient normothermic

Higher threshold for transfusion

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 50/102

9/19/2013

Anesthesia

• Goal

• Does technique make a difference?

Laryngoscopy• Maintenance

• Regional anesthesia

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 51/102

Preoperative Preparation

AnginaMedications to control it

Blood pressure controlled

Diastolic < 95 torr

Congestive heart failure treated

Diuretics

Afterload reduction

Bedrest if indicated

Control diabetes

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 52/102

Preoperative Medications

SedationPrevent tachycardia

Hypertension

Prepared for hypoxiaSupplemental oxygen

Calcium channel blockers not protective of 

perioperative ischemia

Antihypertensives continue on day of surgery

Stop Diuretics

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 53/102

9/19/2013 WE Ellis 82

Antianginal medications

Beta-blockers

Calcium Channel BlockersNitrates

Nitropaste morning of surgery

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 54/102

Beta Blockers

Negative inotropic effects

Withdrawal following stoppage of betablocker

Unstable angina

Myocardial infarction

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 55/102

Monitoring

EKG

Blood Pressure

Temperature

Pulse oximetry

End tidal CO2

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 56/102

Arterial Catheter

Beat to beat blood pressure monitoring

ABGsEarly detection of hypotension

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 57/102

Laboratory studies

HGB & HCT

Electrolytes

Liver function studiesCreatine clearance

Osmolality

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 58/102

Noninvasive beat to beat

analysis

Finapress

Ohmeda

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 59/102

PA catheter

Assessment of LV Function

Early detection of ischemia

“v” waves 

Increased PCWP

More accuracy than CVP

Intravascular volume problems

Especially in patients with severe lung disease

Transesophageal

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 60/102

Transesophageal

Echocardiography

Demonstrates regional wall motion

abnormalitiesSuggestive of ischemia

Most accurate measure of left ventricular

volume

Non-invasive Continuous Cardiac

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 61/102

Non invasive Continuous Cardiac

Output Monitors

Transesophageal Doppler

Thoracic impedance

Limited

Accuracy is controversial

No information about systemic

vascular resistance

Measure CVP

Improved outcomes

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 62/102

Improved outcomes

Aggressive monitoring & treatmentVasoactive drugs

Reduced intraoperative ischemia

MI < 6 months has better survival rateOccurrence reduced from 30-5%

Multi-institution study over last 10 years

5000 patients

Continued for 3 days post-operatively

Decision to use Invasive

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 63/102

Decision to use Invasive

Monitoring

Patients with severe inoperable CAD

Chronic stable angina undergoing significant

abdominal or thoracic surgery

Large blood loss

History of remote MI with stable angina

Not necessary to use invasive monitors

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 64/102

Anesthetic Management

Regional vs general

Anesthetic management skills more

important than technique

Safest technique is the one the practitioner

does best

General anesthesia

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 65/102

General anesthesia

Avoids sympathectomy

Risks with intubation

Sympathetic stimulation

Hypoxia

Increased catecholamines

Loss of subjective monitor

Chest pain

Ischemia

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 66/102

General Anesthesia required

Narcotics

Effective control of catecholaminesRespiratory depression

Prolonged ventilation

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 67/102

Avoid Ketamine

Hypertension

TachycardiaUse in trauma

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 68/102

Etomidate

Painful to inject

More CV stability

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 69/102

Barbiturate

Direct depressant

Extended duration of activity

Smaller doses1-2 mg/kg

Add benzodiazepines and narcotic

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 70/102

Benzodiazepines

Quell anxiety

Hemodynamic stability

Extended duration of actionPotential for hypoxia

Lidocaine

Esmolol

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 71/102

Muscle Relaxants

Avoid pancuronium

Tachycardia

ST segment changes consistent with ischemia

Doxacurium

Duration similar to pancuronium

No cardiovascular effects

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 72/102

Avoid Histamine releasing drugsCurare

Atracurium

Mivacurium <15 mcg/kg

Hypotension

Tachycardia

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 73/102

Inhalation Agents

Potential for coronary steal

Alters coronary autoregulation

Alters regional blood flow

Little influence on outcome

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 74/102

Nitrous Oxide

Constricts coronary arteries

Aggravates myocardial ischemia

High FiO2 recommended

Maintain saturation at 95-100%

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 75/102

Regional Anesthesia

Monitor patient more accurately

Control sympathetic responsesFluids

Esmolol

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 76/102

Intraoperative predictors

Choice of anesthetic

Site of surgery

Duration of AnesthesiaEmergency Surgery

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 77/102

Intraoperative predictors

Choice of AnestheticNo difference in infarction rate GETA vs. Regional

No significant hypotension

No significant tachycardia

TURP

Regional decreased risk post MI

Reinfarction rate

SAB < 1%

GETA 2-8%

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 78/102

Intraoperative predictors

Choice of AnestheticPatient with CHF will benefit from regional technique

Sympathectomy

Decreased preload

Coronary Steal

Potent inhalation agents vs. narcotics

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 79/102

Intraoperative predictors

Site of SurgeryThoracic and upper abdominal

2-3 X’s risk of extremity procedures 

Duration of Anesthetic

> 3 hours > risk of morbidity & mortality

Emergency Surgery

2 - 5 X’s greater risk than nonemergent surgery 

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 80/102

Cardioactive drugs

Nitroglycerin

Lower LVEDPVasodilator

Poor ventricular function

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 81/102

Esmolol

Control heart rate and blood pressure

InductionEmergence

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 82/102

Labetalol

Mixed alpha and beta

Control hypertensionHeart rate management

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 83/102

Lidocaine

Blunt effects of intubation

1.5 mg/kg 4-6 minutes prior to

intubation

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 84/102

Clonidine

Less hypertension

Decreased anesthesia requirements

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 85/102

Nifedipine

Controlling hypertension

Manage coronary artery spasm

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 86/102

Postoperative Management

Maintain analgesia

Balance supply and demand

Supplemental oxygenContinue monitoring into postoperative

period

Early transfusion

Coronary Artery Disease

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 87/102

Coronary Artery Disease

Major GoalBalance Supply and Demand

Primary Determinants of Myocardial Oxygen

DemandWall tension and Contractility

Coronary Artery Disease

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 88/102

Coronary Artery Disease

Factors modifying coronary blood flowdiastolic time

perfusion pressure

coronary vascular tone

intraluminal obstruction

Coronary Artery Disease

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 89/102

Coronary Artery Disease

Myocardial O2 Extractioninfrequently the cause of ischemia intraoperatively

Arterial O2 Content

Correction of anemia

High FiO2

Hemodynamic Goals for the

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 90/102

Hemodynamic Goals for the

Patient with CADP - keep the heart small, decrease wall

tension, increase perfusion pressure

A - maintain, hypertension better than

hypotension

C - depression is beneficial when LV function is

adequate

R - slow, slow, slow

Hemodynamic Goals for the

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 91/102

Hemodynamic Goals for the

patient with CADRhythm - usually sinus

MVO2 - control of demand frequently not

enough, monitor for and treat “supply

ischemia

CPB - elevated ventricular filling pressure

usually not needed after CABG

Anesthetic Technique

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 92/102

Anesthetic Technique

Goals of Anesthesialoss of conciousness

amnesia

analgesia

suppression of reflexes (endocrine and autonomic)

muscle relaxation

Inhalation Agents

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 93/102

Inhalation Agents

AdvantagesMyocardial oxygen balance altered favorably by

reductions in contractility and afterload

Easily titratableCan be administered via CPB machine

Rapidly eliminated

Inhalation Agents

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 94/102

Inhalation Agents

DisadvantagesSignificant hemodynamic variability

May cause tachycardia or alter sinus node function

Possibility of “coronary steal syndrome” 

Coronary Steal

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 95/102

Coronary Steal

Arteriolar dilation of normal vessels diverts bloodaway from stenotic areas

Commonly associated with adenosine, dipyridamole,

and SNPForane causes steal and new ST-T segment depression

May not be important since Forane reduces SVR,

depresses the myocardium yet maintains CO

Opioids

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 96/102

Opioids

AdvantagesExcellent analgesia

Hemodynamic stability

Blunt reflexes

Can use 100% oxygen

Opioids

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 97/102

Opioids

DisadvantagesMay not block hemodynamic and hormonal

responses in patients with good LV function

Do not ensure amnesiaChest wall rigidity

Respiratory depression

Induction Drugs

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 98/102

Induction Drugs

Barbiturates

Benzodiazepines

Ketamine

Etomidate

Nitrous Oxide

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 99/102

Nitrous Oxide

Rarely used due to:increased PVR

depression of myocardial contractility

mild increase in SVR

air expansion

Muscle Relaxants

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 100/102

Muscle Relaxants

Used to:facilitate intubation

prevent shivering

attenuate skeletal muscle contraction duringdefibrillation

Postoperative predictors

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 101/102

Postoperative predictors

Ischemia does occur most commonly in thepostoperative period

Persists for 48 hours or longer following non-cardiac

surgery

Predictor value is unknown

Goldman, L., (1983) Cardiac Risk and Complications of 

noncardiac surgery, Annals of Internal Medicine.

98:504-513

7/29/2019 Cardiac Considerations Post MI

http://slidepdf.com/reader/full/cardiac-considerations-post-mi 102/102

Recommended