Dr.Kanchan Chauhan

Associate Professor in Anaesthesiology

INTRODUCTION

Stress due to surgery leads to an increase in cardiac output which can be achieved easily by normal patients, but which results in substantial morbidity and mortality in those with cardiac disease.

Most suitable anaesthetic can be given by understanding different cardiac disease.

The skill with which the anaesthetic is selected and delivered is more important

than the drugs used.

No. of patients with cardiac disease are increasing. due to the fact that the surgery is being performed on older patients in whom the incidence of coronary artery disease (CAD) is higher, and secondly, recent advances in diagnostic technology have allowed us to detect CAD in asymptomatic or mildly symptomatic patients.

With increased awareness and improved cardiac surgical results, patients who have undergone corrective cardiac surgery are also presenting for

noncardiac surgery.

What Should be our Approach ? Preoperative – Pre anaesthetic evaluation, Risk stratification and preparation

Intraoperative – Smooth induction , Smooth recovery , Smooth monitoring

Postoperatively – Cont. monitoring and vigilance

Pre anaesthetic evaluation ASSESSMENT OF PERIOPERATIVE RISK

Goldman Cardiac Risk Index.  Lee’s risk stratification criterion Detsky’smodified approach to Goldman index NYHA Classification Canadian Cardiovascular Society Classification

Follow AHA ( American Heart Association) guidelines for perioperative cardiovascular evaluation

Medications : Keep in Mind Continue all antianginals, anti hypertensives Continue anti arrythmics Continue Beta blockers and Statins Continue Aspirin (not in some institue)

Discontinue Diuretics, Digitalis, Oral hypoglycemics, ACE inhibitors

O T Preparation Ready Emergency cardiovascular drugs (iv beta blockers, NTG, SNP, Inotropes,

Ephedrine, Phenylephrine, CCB, anti arrythmics etc.

Cardiac equipments :Defibrillator, Pacemakers, Syringe pump

Monitoring

ECG

Blood Pressure

Temperature

Pulse oximetry

End tidal CO2

Arterial Catheter

Beat to beat blood pressure monitoring

ABGs

Early detection of hypotension

Laboratory studies

HGB & HCT

Electrolytes

Liver function studies

Creatine clearance

Osmolality

PA catheterAssessment of LV Function

Early detection of ischemia“v” waves

Increased PCWP

More accuracy than CVPIntravascular volume problems

Especially in patients with severe lung disease

Transesophageal Echocardiography

Demonstrates regional wall motion abnormalities

Suggestive of ischemia

Most accurate measure of left ventricular volume

Non-invasive Continuous Cardiac Output Monitors

Transesophageal Doppler

Thoracic impedance

Limited

Accuracy is controversial

No information about systemic vascular resistance

Measure CVP

Invasive Monitoring

Temperature

Keep warm

Decreasing temperatureShift Oxygen dissociation curve to left

Hemoglobin retains oxygen at tissue level

Prevent alkalosis

04/11/23 WE Ellis 13

Preoperative Preparation

AnginaMedications to control it

Blood pressure controlledDiastolic < 95 mm hg

Congestive heart failure treatedDiuretics

Afterload reduction

Bedrest if indicated

Control diabetes

Our Approach 2012 for beta blockers

Continue beta blockers for those already receiving Initiate beta blockers prior to surgery (cautiously) for

patients who would otherwise need them -

Begin low dose as early as possible- >1 week - not day of surgery Titrate to heart rate (60-70) and BP

Carefully follow those on beta blockers in the postoperative period Hypotension Bradycardia Postoperative tachycardia: look first for a treatable cause

(hypovolemia, anemia) rather than just increasing beta blocker dose.

Anesthesia Goal Does technique make a

difference? Laryngoscopy Maintenance Regional anesthesia

04/11/23 WE Ellis 16

Anesthetic Technique

Goals of Anesthesialoss of conciousness

amnesia

analgesia

suppression of reflexes (endocrine and autonomic)

muscle relaxation

Anesthetic Management

Anaesthetic techniques –

Local anaesthesia

Regional anaesthesia

Combined Regional – General anaesthesia

General anaesthesia

Anesthetic management skills more important than technique.

Safest technique is the one the practitioner does best.

Anaesthetic technique must be based on the type of surgery and the desired haemodynamic goals during anaesthesia.

Role of Local Anaesthesia LA should be with appropriate IV sedation

Large doses of anaesthetic should be avoided - cardiac toxicity - dysrrhythmias and myocardial depression.

Epinephrine with LA - tachycardia, which is undesirable and should be avoided.

Monitored with an ECG, BP and a pulse oxymeter. Supplemental oxygen therapy

Regular verbal contact with patient are important.

Regional Anaesthesia

Intraoperative adverse cardiac events do not differ when general or regional anaesthesia is used.(study shows)

Certain procedures have shown better outcome under RA. E.g.- McLaren et al found no mortality under spinal anaesthesia

for fracture neck femur, versus 25%mortality after GA. Patients with prior MI undergoing transurethral resection of

prostate had <1% reinfarction rate after spinal versus 2-8% after GA.

Regional Anaesthesia RA - loss of sympathetic efferent tone - rapid

haemodynamic deterioration contraindicated in severe aortic stenosis or

hypertrophic obstructive cardiomyopathy.

In a patient with a failing heart who is dependent on sympathetic tone –

central neural blockade can

precipitate cardiac arrest.

Monitor patient more accurately

Control sympathetic responses

Combined Regional-General Anaesthesia Requires a lot of experience on the part of anaesthesiologist.

E.g. - For lower abdominal surgery, a combination of lumbar epidural analgesia and GA can be considered when long surgical procedure, large blood loss or marked hypothermia is anticipated.

The combination of thoracic epidural and GA can be used for upper abdominal, thoracic and major vascular surgery.

The main advantages of epidural blockade are superior postoperative analgesia and less diminution of vital capacity.

Epidural analgesia by suppressing pain improves transmural distribution of regional myocardial blood flow and thus minimizing myocardial ischaemia.

General anesthesia Most common anaesthetic technique used for cardiac

patients undergoing noncardiac surgery. Avoids sympathectomy

Risks with intubation

Sympathetic stimulation

Hypoxia

Increased catecholamines

Loss of subjective monitor

Chest pain

Ischemia

General Anesthesia required

I. Pre-anaesthetic medication Integral part of anaesthetic practice ( particularly in patients with CAD

and hypertension.)

Benzodiazepines –

Quell anxiety

Hemodynamic stability

Extended duration of action

Potential for hypoxia Intravenous narcotics (e.g. Fentanyl)

Effective control of catecholamines

Respiratory depression

Prolonged ventilation

OpioidsAdvantages

Excellent analgesia

Hemodynamic stability

Blunt reflexes

Disadvantages

May not block hemodynamic and hormonal responses in patients with good LV function

Do not ensure amnesia

Chest wall rigidity

Respiratory depression

Inductions AgentsAvoid Ketamine

HypertensionTachycardiaUse in trauma

EtomidatePainful to injectMore Cardiovascular stability

BarbiturateDirect depressantExtended duration of activitySmaller doses

1-2 mg/kgAdd benzodiazepines and narcotic

Propofol Outpatient anaesthesia (quick recovery) Benzodiazepines

Laryngoscopy and intubation Adequate depth of anaesthesia should be ensured prior to

intubation.

Fentanyl 5-8 mgm/kg can be given to blunt the sympathetic responses to

laryngoscopy and intubation.

Lidocaine

Blunt effects of intubation

1.5 - 2 mg/kg 4-6 minutes prior to intubation

Esmolol i.v. – 0.5 to 1mg/kg 90 sec before intubation

Muscle Relaxants Succinylcholine is notorious - producing arrhythmias. Avoid pancuronium

Tachycardia

ST segment changes consistent with ischemia (Pancuronium may be used in patients with CAD who have a slow heart rate) Vecuronium provides minimal haemodynamic alterations. Doxacurium -cardiovascular stable. Rocuronium should be considered during rapid sequence induction

technique.

Avoid Histamine releasing drugs

Curare

Atracurium

Mivacurium <15 mcg/kg

- Hypotension ,Tachycardia

Nitrous Oxideincreased PVR

depression of myocardial contractility

mild increase in SVR

air expansion Constricts coronary arteries

Aggravates myocardial ischemia

High FiO2 recommended Maintain saturation at 95-100%

N2O - Detrimental effects in patients with CHF, pulmonary hypertension and regional myocardial ischaemia

Inhalation Agents

Advantages

Myocardial oxygen balance altered favorably by reductions in contractility and afterload

Easily titratable

Can be administered via CPB machine

Rapidly eliminated

Disadvantages

Significant hemodynamic variability

May cause tachycardia or alter sinus node function

Possibility of “coronary steal syndrome”

Inhalation Agents Depress myocardium, Cause arterial and venous dilation and decrease sympathetic nervous activity.

decrease in BP and CO, and thus decrease in myocardial oxygen consumption.

(advantageous in patients with CAD, may produce cardiovascular collapse in patients with poor myocardial reserve.)

Potential for coronary steal - isoflurane

Alters coronary autoregulation

Alters regional blood flow

Little influence on outcome

Coronary Steal

Arteriolar dilation of normal vessels diverts blood away from stenotic areas

Commonly associated with adenosine, dipyridamole, and SNP

Isoflurane causes steal and new ST-T segment depression

May not be important since Isoflurane reduces SVR, depresses the myocardium yet maintains CO

Intraoperative predictors

Choice of AnestheticNo significant hypotension

No significant tachycardia

Site of SurgeryThoracic and upper abdominal

2-3 X’s risk of extremity procedures

Duration of Anesthetic> 3 hours > risk of morbidity & mortality

Emergency Surgery2 - 5 X’s greater risk than nonemergent surgery

Cardioactive drugsNitroglycerin

Lower LVEDP , Vasodilator

Esmolol

Control heart rate and blood pressure

Labetalol

Control hypertension , Heart rate management

Clonidine

Less hypertension , Decreased anesthesia requirements

Nifedipine Controlling hypertension Manage coronary artery spasm

Coronary Artery DiseaseMajor Goal

Balance Supply and Demand

Primary Determinants of Myocardial Oxygen Demand

Wall tension and Contractility

Factors modifying coronary blood flow

diastolic time

perfusion pressure

coronary vascular tone

intraluminal obstruction

Hemodynamic Goals for the Patient with CADPreload - keep the heart small, decrease wall

tension, increase perfusion pressure

Afterload - maintain, hypertension better than hypotension

Contractility - depression is beneficial when LV function is adequate

H R - slow

Rhythm - usually sinus

MVO2 - control of demand frequently not enough, monitor for and treat ischemia

Monitored Anaesthesia Care Employed in CAD patients

Patients carrying the highest risk are selected Minimum anaesthetic interference Adequate analgesia is mandatory

Failure to suppress the stress response Highest incidence of 30 day mortality

(isacon 2008)

HEART FAILURE Inability of the heart to pump enough blood to match tissue requirements. Commonest cause ischaemic heart disease. Other causes include hypertension, valvular heart disease and

cardiomyopathies.

Note that with an increase in contractility there is a greater cardiac output for the same ventricular end- diastolic volume.

.  Drug treatments may include ACE (angiotensin converting enzyme)

inhibitors, diuretics and nitrates.

Echocardiogram to assess ejection fraction - values of less than 30% equate to severe heart failure.

Anaesthesia consideration Preload can be reduced with diuretics and nitrates, and both

central venous and pulmonary artery pressures can be monitored.

Trans-oesophageal echocardiography, if available, is a useful tool to visualize overall cardiac performance.

Maintenance of myocardial contractility - in particular inotropes may be needed to oppose the cardiodepressant action of anaesthetic agents. 

Reduction of afterload by vasodilation, for example as a secondary effect of spinal or epidural anaesthesia. This not only reduces myocardial work, but helps maintain cardiac output. However, the benefit of such actions may be limited by falls in blood pressure which can compromise blood flow to vital organs such as the brain and kidneys. So balance should be there

Valvular Heart Disease

Aortic Stenosis

Aortic Insufficiency

Mitral Stenosis

Mitral regurgitation

Mitral Stenosis

Characterized by:

Normal ventricular function

Obstruction to left atrial emptying decreases cardiac output

Pulmonary congestion from elevations in LA and pulmonary venous pressure

Pulmonary hypertension and RVH over time

Hemodynamic Goals for the Patient with MSPreload - Enough to maintain flow across stenotic valve so

to maintain ventricular feeling, excess fluid may cause pulmonary edema

Afterload – SVR should be maintained,avoid decrease in SVR

Avoid increased RV afterload (PVR)

Contractility - LV usually ok until after CPB, with longstanding PHTN, RV may be impaired

HR -keep slow to allow time for ventricular filling, AVOID SINUS TACHYCARDIA

Hemodynamic Goals for the Patient with MS Rhythm - Often atrial fibrillation, control ventricular

response

MVO2 - Not a problem

CPB - Vasodilators may help post-CPB RV failure, control of ventricular response may be difficult

epidural preffered over spinal

phenylephrine preffered over ephedrine

Mitral Regurgitation

Characterized by:

Chronic volume overload similar to AI

Increased ventricular compliance without change in LVEDP

May mask signs of impaired ventricular function

Hemodynamic Goals for the Patient with MIPreload – maintain or slightly increase ;an elevated preload

may cause increase in regurgitant flow and low preload may cause inadequate cardiac output Usually pretty full, may need to keep that way

Afterload - Decreases are beneficial, increases augment regurgitant flow, avoid sudden increase in SVR

Contractility - Unrecognized myocardial depression possible, titrate myocardial depressants carefully, maintain or increase to decrease left ventricular volume

HR – maintain or increase , avoid bradycardia which worsens regurgitant flow

Hemodynamic Goals for the Patient with MIRhythm - Atrial fibrillation is occasionally a problem

MVO2 - only if associated with CAD, then caution!

CPB - New valve will increase afterload, unmasking impaired ventricle

Spinal and epidural well tolerated but avoid bradychardia

Mitral valve prolapse- anaesthesia consideration Aboid decrease in preload

Continue antiarrhythmic drugs

Same consideration as for MI

Aortic Stenosis

Characterized by:

Obstruction to LV outflow

Intraventricular systolic pressure and wall tension increase

Concentric hypertrophy

Decreased LV compliance

Reliance on atrial contribution

Hemodynamic Goals for the Patient with ASPreload - full, adequate intravascular volume to fill

noncompliant ventricle and to maintain BP

Afterload - already elevated but relatively fixed, coronary perfusion pressure must be maintained,

Contractility - usually not a problem, inotropes may be helpful preinduction in end-stage AS with hypotension

Watch out for vasodilation

Treat hypotension with phenylephrine

Hemodynamic Goals for the Patient with ASRate - not too slow (decrease CO), not too fast

(ischemia)

Rhythm - Sinus!! Cardioversion if hemodynamic instability from SV dysrhythmias

MVO2 - Ischemia is an ever present risk, Avoid tachycardia and hypotension

Mild to moderate may tolerate spinal and epidural (epidual preferred)

spinal and epidural contraindicated in severe AS

High risk of myocardial ischaemia

Aortic InsufficiencyCharacterized by:

Chronic volume overload

Ventricular dilatation

Eccentric hypertrophy

Forward stroke volume higher than normal causing increased systolic pressure

Regurgitation across the valve causes diastolic pressure to be lower than normal

Hemodynamic Goals for the Patient with AIPreload - normal to slightly increased to maximize

forward cardiac output and maintain BP

Afterload - Reduction beneficial with anesthetics or vasodilators,increases augment regurgitant flow, avoid sudden increase in afterload

Contractility - usually adequate

Rate - Modest tachycardia shortens diastolic phase decreases regurgitant fraction and increases cardiac output

Most patient tolerate spinal or epidural provided intravascular volume is maintained

Aortic Insufficiency Once asymptomatic death can occur with in 5 yrs

unless lesion is surgically repaired

Digitalis , Diuretics and afterload reduction (ACE inhibitors) for chronic cond. (eventual surgical repair)

Inotropes (dopamine,dobutamine) and vasodilators for severe,chronic aortic regurgitation

(requires surgery)

Hemodynamic Goals for the Patient with AI Rhythm - usually sinus, not a problem

MVO2 - Not usually a problem

CPB - observe for ventricular distention (decreased HR, increased ventricular filling pressure) when going onto bypass

Hypertension – Anaesthesia consideration

HTN (defined as a diastolic BP>90mmHg or a systolic BP>140mmHg in adults) is the most common of all the cardiovascular diseases.

Most patients are under adequate control preoperatively and their medication should be continued till the day of surgery.

Poorly controlled or uncontrolled hypertensives are at increased risk of perioperative complications such as ischaemia, MI, arrhythmias and cerebrovascular accidents (CVA).

In mild hypertensive patients a single dose of long acting beta-blocker may reduce the risk of myocardial ischaemia during stressful periods.

However, in patients with moderate to severe HTN, cardiology consultation should be obtained and BP brought under control prior to elective surgery.

Coronary Artery Revascularization Prophylaxis Trial (CARP)

Coronary revascularization prior to vascular surgery is not of benefit in the patient with stable CAD if treated with beta blockers, aspirin, statins in the absence of: unstable coronary diseaseleft main coronary diseaseaortic stenosissevere left ventricular dysfunction

Elective vascular surgery in high risk patients.101 patients3 or more cardiac risk factorsAll with extensive inducible ischemia by stress test43% with LVEF < 35%75% with Left main or 3-vdAll received beta blocker titrated to HR 60-65Antiplatelet agents continued in perioperative period

No benefit of prophylactic coronary revascularization

How about the patient who has already received a stent and requires noncardiac surgery ?

Drug eluting stent related issues

Stent thrombosisASA + clopidogrel

HemorrhageASA + clopidogrel

Joint Advisory Recommendations and Noncardiac Surgery Consider bare metal stent if patient requires PCI and is

likely to require invasive or surgical procedure within next 12 months.

Educate patient prior to discharge re: risk of premature antiplatelet discontinuation

Instruct patient to contact treating cardiologist before antiplatelet discontinuation

Healthcare providers who perform surgical or invasive procedures must be made aware of catastrophic risks of premature antiplatelet discontinuation and should contact the treating cardiologist to discuss optimal management strategy

Joint Advisory Recommendations and Noncardiac Surgery

Defer elective procedures for which there is bleeding risk until completion of antiplatelet course 1 month bare metal stent 12 months drug eluting stent

For patient with drug eluting stent who are to undergo procedures that mandate discontinuation of thienopyridine (eg, clopidogrel), continue aspirin if at all possible and restart thienopyridine as soon as possible

No evidence for “bridging therapy” with antithrombins, warfarin, or glycoprotein IIb/IIIa agents

Postoperative predictors

Ischemia does occur most commonly in the postoperative 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

Postoperative Management

Maintain analgesia

Balance supply and demand

Supplemental oxygen

Continue monitoring into postoperative period

Early transfusion

Key Points Clearance. Perform evaluation and make recommendations that

will relate to perioperative and long – term issues.

Tests only if likely to influence treatment.

Preoperative coronary revascularization if independently indicated.

Selective use of beta blockers. (beware bradycardia)

Statins Beware of premature antiplatelet discontinuation in the patient

post PTCA stent.

Continue beta blocker, aspirin, statins,

Summary Patients with cardiac disease present for

anaesthesia every day.

Since their perioperative courses are associated with greater morbidity and mortality, it is important to provide a haemodynamically stable anaesthetic

This requires knowledge of the pathophysiology of the disease, and of the drugs and procedures and their effects on the patient.

THANKS