Topic-management of Anaesthesia in Patients With Ischemic Heart

8/8/2019 Topic-management of Anaesthesia in Patients With Ischemic Heart

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MODERATOR:

PRESENTER :

DR.YASHOBANTA SINGHPOST GRADUATE TRAINEE

DEPT.OFANAESTHESIOLOG

Y

AMCH



` Ischemic heart disease is present in an estimated 30%

of patients who undergo surgery in the United States.

` It is estimated that 500,000 to 9oo,000 perioperative

MIs occur annually worldwide.` Angina pectoris, acute myocardial infarction and sudden

death are the first manifestations of this disease.

` Cardiac dysrhythmias are the major cause of death.

` The most important risk factors for development of atherosclerosis are male gender and increasing age.



` Male gender

` Increasing age

` Obesity

` Sedentary life style` Genetic factors/family history

` Diabetes mellitus

` Hypertension

` Hypercholesterolemia





Terminology of acute coronary syndrome

AcuteCoronarySyndrome

12 ± leadECG

No ST

segmentelevation

Troponin/CK-MB negative

Unstableangina

Troponin/CK± MB positive

Non ST ±Elevated M.

I.

ST segmentelevation

Troponin/ CK± MB positive

ST elevated

M.I.



` Chronic stable angina refers to chest pain or discomfort

that does not change appreciably in frequency or

severity over 2 months or longer.

` An imbalance between myocardial oxygen supply andmyocardial oxygen demand can precipitate ischemia

which manifests as angina pectoris.

` Atherosclerosis is the most common cause of impaired

coronary blood flow resulting in angina pectoris.



` Investigations;

` Electrocardiography- standard ECG and exercise ECG

` Non invasive imaging tests-

` Echocardiography` Nuclear stress imaging

` Electron beam CT

` Coronary angiography



` Treatment-

` Lifestyle modification.

` Medical treatment:

` Antiplatelet drugs, Blockers,CCBs,Nitrates, ACEinhibitors.

` Revascularization by CABG or PCI with or without stents

when medical therapy fails to control angina pectoris.



` It represents a hypercoagulable state.

` Patients with ST elevation at presentation are

considered to have STEMI.

` Patients who present with ST segment depression or non specific changes on the ECG are categorised as

UA/NSTEMI on the levels of cardiac specific troponins

or CK- MB.

` Many more patients present with UA/NSTEMI than withSTEMI.



` Nearly all MIs are caused by thrombotic occlusion of a

coronary artery.

` Long term prognosis is determined by severity of LV

dysfuntion,presence and degree of residual ischemiaand potential for malignant ventricular arrthymias.

` STEMI occurs when coronary blood flow decreases

abruptly due to acute thrombus formation at a site when

a atheromatous plaque ruptures,fissures or ulcerates.



` DIAGNOSIS:

` Diagnosis requires at least 2 of these 3 criteria:

` Chest pain

` Serial ECG changes indicative of MI` Increase /decrease of serum cardiac enzymes.

` LABORATORY STUDIES- serum cardiac enzymes

` IMAGING STUDIES- Echocardiography , myocardial

perfusion imaging studies.





` UA/NSTEMI results from a reduction in myocardial oxygen

supply.

`

Rupture/erosion of atheromatousplaque,embolisation,thyrotoxicosis,fever,sepsis,tachycardia,a

naemia,drugs may lead to UA/NSTEMI.

` DIAGNOSIS:

` It has 3 principal presentations: angina at rest, recent onset

angina or an increase in frequency or severity of previously

stable angina.

` Can also present with hemodynamic instability or CHF.

` ECG changes and elevation of cardiac specific enzymes.



TREATMENT:

Management is directed at decreasing myocardial oxygen

demand.

Bed rest, supplemental oxygen,analgesia and Blocker therapy are indicated.

Aspirin or clopidogrel and 48 hours of LMW heparin are

recommended.

Patients at high risk ± early invasive therapy whichincludes coronary angiography and revascularisation by

CABG or PCI.



` Cardiac dysrhythmias: ventricular fibrillation,VT, Atrial

fibrillation,bradydysrhythmias and heart block.

` Pericarditis

` MR` Ventricular septal rupture

` CHF and cardiogenic shock

` Myocardial rupture

` Right ventricular infarction

` Cerebrovascular accident



` Its incidence is a cumulative result of preoperativemedical condition,specific surgicalprocedure,expertise of surgeon,diagnostic criteriato define MI and overall medical care.

` Most perioperative MIs occur in the first 24 to 48hours after surgery.

` It may be related to acute coronary thrombosis or due to increased myocardial oxygen demand in

setting of decreased myocardial oxygen supply.









` HISTORY: it is meant to elicit severity, progression

and functional limitations imposed by IHD.

` Silent myocardial ischaemia

` Previous MI` Co-existing noncardiac diseases

` Current medications:

` Blockers,nitrates,CCBs,statins,anti platelet

drugs and ACE inhibitors



` The physical examination of patients with IHD is

often normal.

` Signs of right and left ventricular dysfunction must

be sought.` A carotid bruit may indicate cerebrovascular

disease.

` Orthostatic hypotention may reflect attenuated

ANS activity due to treatment withantihypertensive drugs.

`



` ECG- preoperative stress testing or exercise

tolerance,preoperative ambulatory ECG

` Echocardiography-preoperative transthoracic or

transoesophagialechocardiography,pharmocologic stress testing or

stress echocardiography

` Radionuclide ventriculography

` thallium scintigraphy` CT and MRI

` PET



` Goals ± 1)determining the extent of IHD and any

previous interventions; CABG,PCI.

` 2)determining severity and stability of disease.

` 3)reviewing medical therapy and noting any anydrugs that can increase risk of surgical bleeding or

contraindicate a particular anaesthetic technique.



` Lee revised cardiac risk index: in stablepatients undergoing elective major non cardiacsurgery 6 independent predictors of major cardiac

complications` These risk factors have been incorporated into the

ACC/AHA guidelines for perioperativecardiovascular evaluation for non cardiac surgery

` The ACC/AHA guidelines provide a multistepalgorithm for determining need for preoperativecardiac evaluation.



CLINICAL VARIABLES POINTS

1. HIGH RISK SURGERY 1

2. CORONARY ARTERY DISEASE 1

3. CONGESTIVE HEART FAILURE 1

4. H/O CEREBROVASCULAR DISEASE 1

5. INSULIN TREATMENT FOR DIABETES

MELLITUS

1

6. PREOPERATIVE SERUM CREATININE

> 2 mg/dl

1



RISK CLASS POINTS RISK OFCOMPLICATIONS

1. VERY LOW 0 .4%

2. LOW 1 .9%

3. MODERATE 2 6.6%

4. HIGH 3+ 11%



` The ACC/AHA guidelines integrate risk stratificationaccording to clinical risk factors(major,intermediateand minor), functional capacity and surgery specificrisk factors.

` Functional capacity or exercise tolerance can beexpressed in MET units. O2 consumption of 70 kg , 40year old man in resting state is 3.5 ml/kg/min or 1MET.Perioperative cardiac risk is increased in patients withpoor functional capacity that is who are unable meet a4 MET demand during normal activities.

` The surgery specific risk is graded as high,intermediate or low.



An algorithm for preoperative assessment of patients with ischemic heart

disease

Patient

Elective

Stable

Stratify risks

UnstableCAD

Cardiologyconsultation

Emergentsurgery

Proceed tosurgery









` Three therapeutic options are available before

elective non cardiac surgery-1) revascularisation

by surgery2)revascularisation by PCI 3)Optimal

medical management.` CABG

` PCI- angioplasty before elective surgery could

improve outcome.It is done with stent placement

which requires antiplatelet therapy



` High risk individuals will be identified and treated toreduce their risk of perioperative cardiaccomplications.

` NTG is helpful in management of active ischaemia.

` Perioperative use of Blockers is effective in reducingperioperative mortality and morbidity.

` Alpha 2 agonists have analgesic, sedative andsympatholytic effects. Can be used in patients inwhom Blockers are contraindicated.

` ACE inhibitors,statins, aspirin,glucose-insulin-potassium infusion may be benefecial.



` Objectives are ;

` 1)to prevent myocardial ischaemia by optimisingmyocardial o2 supply and reducing myocardial o2demand.

` 2)to monitor for ischaemia and to treat ischaemiaif it develops.

` Intraoperative events associated with persistenttachycardia,systolic hypertension,sympathetic

nervous system stimulation,arterial hypoxemia or hypotension can adversly affect the patient.



` Decreased o2 delivery:

` Decreased coronary blood flow

` Tachycardia

` Diastolic hypotension

` Hypocapnia

` Coronary artery spasm

` Increased o2 demand:

` Sympathetic nervous system stimulation

` Tachycardia` Hypertension

` Increased myocardial contractility

` Increased preload

`

Increased afterload



` INDUCTION OF ANAESTHESIA;

` Can be done with an IV induction drug.

` Ketamine is not recommended.

` Intubation by administration of Sch or a non depolarisingmuscle relaxant.

` Short duration direct laryngoscopy.

` Laryngotracheal lidocaine, IV lidocaine, esmolol,and

fentanyl may be useful for blunting tachycardia evokedby tracheal intubation.



` MAINTENANCE OF ANAESTHESIA:

` Volatile anaesthetic alone or in combination with N2O

may be administered.

` Equally acceptable is N2O ± opioid technique withaddition of volatile anaesthetic agent.

` For patients with severely impaired LV function rather

then volatile anaesthetics , opioids may be used.

` Regional anaesthesia is an acceptable technique .However decrease in BP associated with spinal or

epidural anaesthesia must be controlled.



` CHOICE OF MUSCLE RELAXANTS:

` Muscle relaxants with minimal or no effect on HR andBP ±VECURONIUM,ROCURONIUM,CISATRACURIUM may

be used.` Histamine release and resulting decrease in BP caused

by atracurium are less desirable.

` Pancuronium produces tachycardia and hypertension so

not preferred.` Reversal with an anticholinesterase/anticholinergic

combination can be safely used.GLYCOPYROLATEwhich has much less chronotropic effect than atropine is

preferred.



` MONITORING

` Perioperative monitoring is influenced by complexity of operative procedure and severity of IHD.

` ECG : it is simplest,most cost effective method for detecting perioperative myocardial ischaemia.diagnosischarecterised by depression or elevation of ST segmentof at least 1 mm. T wave inversion and R wave changesmay also be associated.Leads V4 and V5 or V3,V4,V5

are the sets of three leads recommded.` Pulmonary artery catheter

` Transesophageal echocardiography.



` Tr eatment should e instituted hen ther e ar e mm T

segment changes on the ECG.

` A per sistent incr ease in R can e tr eated y I Blocker

such as esmolol .

` NTG is a mor e appr opriate choice hen myocar dial ischemia

is associated ith a nor mal to modestly elevated BP .

` ypotension is tr eated ith sympathomimetic dr ugs to

r estor e cor onar y perf usion pr essur e.In addition fluid

inf usion may e usef ul to help r estor e BP.

` In an unstable hemodynamic situation cir culator y support

ith inotr opes or an IAP or postoper ative car diac

catheterisation may be necessar y.



` The goals of postoperative management are to preventischaemia, monitor for myocardial injury and treat MI.

` Most adverse cardiac events occur within the first 48 hourspostoperatively,delayed cardiac events within 30 days canoccur due to secondary stresses.

` Patients on Blockers continue to receive these drugsperioperatively.

` Prevention of hypotension and hypovolemia is necessarypostoperatively,also intravascular volume and adequate Hb

concentration must be maintained.` The timing of weaning and extubation is also important.

` Continuous ECG monitoring is useful for detectingpostoperative MI which is often silent.



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Topic-management of Anaesthesia in Patients With Ischemic Heart