Anesthesia In Children With Congenital Heart Disease For Non-cardiac Surgery

Dr. Fady Adib Lecturer Of Anesthesia Ain-Shams University Oct. 2012

The question facing anesthetists are:

1 . Should the patient be referred to specialist cardiologist before surgery?

2 . Should surgery be performed in a center specializing in congenital cardiology?

3 . How should anesthesia be conducted safely in the presence of congenital heart disease?

INTRODUCTION

The

Incidence

of CHD is about 1% of the newborn infants

- Surgery:

- Noncardiac conditions (

inguinal hernia, circumcision, or tonsillectomy).

- Associated noncardiac congenital anomalies

(orthopedic or genitourinary).

- Due to advances in diagnosis, medical, critical and surgical care for CHD - Therefore, it is common for patients with CHD to present for non-cardiac surgery, and even in patient with corrected CHD significant residual problems (arrhythmias, ventricular dysfunction, shunts, valvular stenosis, and PH) may be exist.

Anatomical & Physiological Differences

CVS: Anatomical Differences

- Myocardium is less compliant: Cardiac Output is H.R. dependent.

- It can ’ t withstand a volume load.

- Decreased sympathetic innervation:

 catecholamine stores

Autonomic Development

- Beta receptors develop with age - alpha receptors less developed So V.C response to volume loss is decreased - Parasympathetic response supervens - Net result: - Volume load heart failure - Volume loss decrease vasoconstriction Hypotension

CLASSIFICATION OF CHD

I- Acyanotic congenital heart disease: 1- ASD 2- VSD 3- PDA II- Cyanotic congenital heart disease: 1- Tetralogy of Fallot, with severe right ventricular outflow obstruction 2- TGA 3- Pulmonary atresia or severe stenosis 4- Tricuspid atresia with pulmonary stenosis 5- Truncus Arteriosus

Pathophysiological classification of congenital heart disease

- Shunt lesions - Mixing lesions - Obstructive lesions - Regurgitation lesions

Shunt lesions

Intracadriac

e.g. ASD, VSD

Extracardiac:

e.g. PDA

- Direction & magnitude:

depends on size of shunt orifice pressure on both sides of the shunt - Lt.-to-Rt. Shunt ( e.g. VSD,PDA) VOLUME OVERLOAD - Rt.-to-Lt. Shunt (e.g. Fallot 4) PRESSURE OVERLOAD

..Shunt lesions.. (continued)

Lt-to-Rt shunt

e.g. ASD, VSD

Rt-to-Lt shunt

e.g. F4 - Volume overload on pulmonary circulation

- Increased cardiac

work of Rt. Ventricle

- Excessive pulmonary

blood flow=++ PVR

-

↓

Pulmonary blood

flow= hypoxemia - Pressure overload of the Rt. ventricle

Mixing lesions (large orifice)

- e.g. TGA, Univentricular heart - Direction & Magnitude: Depend on lesion PRESSURE on both sides of the - Usually CYANOTIC - With VOLUME & PRESSURE overload

Obstructive lesions

- e.g. Aortic stenosis, Coarctation of Aorta

- Pressure overload

ventricular hypertrophy impaired coronary perfusion systemic hypotension

Regurgitation lesions (uncommon)

- Volume overload ventricular dilatation

Once full details of the anatomy, surgical history and current pathophysiology are obtained patient can be divided into the following categories: 1 . Congenital heart disease, yet to be surgically treated.

2 . Surgically corrected, symptom free with no new development.

3 . Surgically corrected, symptomatic heart diseases 4 . Surgically palliated. Symptoms stable with no new development 5 . Surgically palliated with severe symptoms or no new development

Types of Cardiac Surgery

Univentricular Usually Palliative

e.g. Shunts, Banding

Biventricular Usually complete repair ( Corrective )

•Problems encountered: Debubbling & Antibiotic coverage, As the lesion is still persistent e.g. VSD

- Corrective surgery: Correct

anatomy

- Palliative surgery: The aim is to

increase or decrease pulmonary blood flow

Corrective Surgery

Corrected ASD VSD PDA: Near normal patient. Only needs antibiotic prophylaxis.

, Repaired TOF: Residual defects: VSD, outflow tract obstruction, pulmonary regurge, Heart block

.

Corrected coarcitation usually require long term treatment of hypertension

Palliative surgery

Decrease PBF: Pulmonary artery banding (VSD) Increase PBF: In Pulmonary atresia .

BT shunt: Subclavian artery to Pulmonary artery Gllen: SVC to Pulmonary artery Fontan after Gllen IVC to Pulmonary artery

Physiology of different types of circulation

- Normal or ‘series’ circulation.

-

- Parallel or ‘balanced’ circulation.

-

- Single-ventricle circulation

-

Risk classification

increased risk of mortality and morbidity.

- factors associated with a high risk of perioperative complications, - {disease complexity, } - {physiological status,} Most Important - type of surgery, young age, and Hospital Stay .

Complexity of heart disease

- single-ventricle physiology - balanced circulation physiology - cardiomyopathy - aortic stenosis

Physiological status

Physiological status can be divided into four major risk factors: - Cardiac failure - Pulmonary hypertension - Arrhythmias - Cyanosis

ANESTHETIC MANAGEMENT

- Perioperative management requires a team approach - CHD is polymorphic and may clinically manifest across a broad clinical spectrum - The plane of Anesthetic Management includes the following: A - Preoperative Management B - Intraoperative Management C - Postoperative Management

Preoperative Anesthetic Considerations

1- Complete history and physical examin.

2- Review all investigations 3- Hydration should be maintained 4- All cardiac medication except possibly digitalis ,ACE and diuretics should be continued until surgery 5- Premedication should be give particularly to patients at risk for right to left shunt 6- Antibiotic prophylaxis against endocarditis must be given

Preoperative Anesthetic Management: A- History B- physical examination C- Investigations D- Premedications E- Fasting Guidelines

HISTORY & PHYSICAL EXAMINATION

- Assess functional status

- daily activities - exercise tolerance

- ↓ cardiac reserve

- cyanosis - respiratory distress during feeding

- Cyanosis - Dyspnea - Fainting attack - Fatigue - Palpitations - chest pain - Syncope - Abdominal fullness - Leg swelling - Medications - Vital signs - Airway abnormality - Associated extracardiac congenital anomalies - Tachypnea, dyspnea, cyanosis - Squatting - Clubbing of digits - Heart murmur (s) - CHF: - Jugular venous distention.

- Hepatomegally - Ascitis - Peripheral edema

MRI 12 Lead ECG INVESTIGATIONS Echocardiography Cardiac Catheterization Laboratory Evaluation chest X – Ray

Regarding investigations of CHD patients for non-cardiac surgery: A- Chest X – Ray has no rule B- Cardiac Catheterization is the first choice for diagnosis of CHD C- Echocardiography non invasive method for diagnosis of CHD D- MRI cannot give us idea about pulmonary veins IM Premedication for CHD patients presenting for non-cardiac suergery: A- Cooperative or unable to take orally B- Ketamine 1mg/kg C- Midazolam 5 mg/kg D -Glycopyrrolate or Atropine 0.02 mg/kg Procedural antibiotic prophylaxis is required in patients with A- Aortic valve replacement B- Mitral valve prolapse with regurge C- Previous history of infective endocarditis D- Ostium secundum ASD

AHA guidelines for bacterial endocarditis Prophylaxis in patients with cardiac conditions Endocarditis prophylaxis recommended Endocarditis prophylaxis not recommended High-risk category

- Complex cyanotic congenital heart disease :

Negligible-risk category

- Physiologic, or functional heart murmurs Transposition of the great vessels - Surgical repair without residua beyond Tetralogy of Fallot 6 months : ASD, PDA,VSD - Surgically created systemic-to-pulmonary shuntsor conduits - Cardiac pacemaker or - implanted defibrillator - Prosthetic, Bioprosthetic, Homograft valves - Previous bacterial endocarditis - Isolated secundum atrial septal defect - Mitral valve prolapse without reg.

Moderate-risk category

- Other congenital cardiac anomalies - Acquired valvular dysfunction - Hypertrophic cardiomyopathies - Mitral valve prolapse with valvar Regurg - Previous coronary artery bypass surgery - Previous rheumatic heart disease without valvular dysfunction

AHA guidelines for antibiotic prophylaxis: dental, oral, Respiratory tract and esophageal procedures Standard prophylaxis Amoxicillin 1 h before procedure -Children: 50 mg/kg p.o. .

Adults: 2.0 g p.o

Unable to take oral medications Allergic to penicillin Unable to take oral medications AND allergic to penicillin Ampicillin within 30 min before procedure - Children: 50 mg/ kg i.m. or i.v.

.

Adults: 2.0 g i.m. or i.v

Clindamycin 1 h before procedure Children: 20 mg/kg p.o.

Adults: 600 mg p.o.

OR Azithromycin or clarithromycin 1 h before procedure -Children: 15 mg/kg p.o.

.

Adults: 500 mg p.o

Clindamycin within 30 min before procedur -Children: 20 mg/ kg i.v

.

-Adult: 600 mg i.v.

AHA guidelines for antibiotic prophylaxis: genitourinary and gastrointestinal procedures High risk patients High risk patients Allergic to penicillin Moderate risk patients Moderate risk patients AND allergic to penicillin

- within 30 min before procedure - Children: Ampicillin 50 mg/ kg .and gentaicin 1.5 mg/kg i.m or i.v

- Adults: Ampicillin 2.0 g and gentamicin 1.5 mg/kg i.m or i.v

- Complete infusion 30 min before procedure - Children: Vancomycin 20 mg/kg i.v over 1-2 hr gentamicin 1.5 mg/kg i.m or i.v

-Adults: Vancomycin 1g/kg i.v over 1-2 hr gentamicin 1.5 mg/kg i.m or i.v

Ampicillin within 30 min before procedure - Children: 50 mg/ kg i.m. or .iv

- Adults: 2.0 g i.m or i.v

Complete infusion 30 min before procedure - Children: Vancomycin 20 mg/kg i.v over 1-2 hr -Adults: Vancomycin 1g/kg i.v over 1-2 hr

Anesthetic Management

A - Preoperative Management B - Intraoperative Management : 1- Monitoring 2- Choice of anesthetic agent 3- Maintenance of anesthesia 4- Emergence from anesthesia

Anesthetic Management

Preoperative Assessment

- Associated congenital anomalies (difficult airway) - Chest: signs of H.F.& chest infection … postpone

- Liver:

● enlarged in Rt. Sided failure ● shrunken in Lt. sided failure, diuretics, ↓feeding

- Cyanotic spells - Acute hypertensive pulmonary crisis

Anesthetic Management

Investigations

- Hematocrit: … .thromboembolism

- Electrolytes: … ..arrhythmias..(should be corrected) - Blood gases: … cyanotic may be acidotic - Echocardiography: satisfactory in simple cases - Catheterization: - Coagulation profile: cyanotic patients usually suffer from coagulopathies.

-

Premedication

Oral Premedication: - Midazolam 0.25 -1.0 mg/kg - Ketamine 2 - 4 mg/kg - Atropine 0.02 mg/kg IV Premedication: - Midazolam 0.02 - 0.05 mg/kg titrated in small increments - Ketamine 1-2 mg/kg IM Premedication: - Uncooperative or unable to take orally - Ketamine 5 – 10 mg/kg - Midazolam 0.2 mg/kg - Glycopyrrolate or Atropine 0.02 mg/kg

Fasting Guidelines

Anesthetic Management

Premedication

- Fasting: clear sugar fluid allowed till 4 hours

↓

6 months: No premedication - 6-9 months: optional e.g. to avoid spell or crisis ↑9

months:

-atraumatic (oral midazolam) -IM: ketamine 2mg/kg add Atropine 0.02mg/kg

Anesthetic Management

O.R. preparation

- Temperature control: mattress & O.R. temp.

- Anesthetic machine: with O 2 , Air, N 2 O

- Infusion set

…… free of air bubbles - Drugs: Atropine, Bicarb., Epinephrine, Phenylephrine - Inotropic infusion should be premixed before induction in high risk patient (e.g.Dobutamine)

Anesthetic Management

Monitoring & Lines

- ECG - Pulse Oximetry: inaccurate in deep hypothermia - Invasive B.P.: Lt. Radial, Rt. Radial, Femoral art.

- CV. Cannulation: Rt. & Lt. IJV, Femoral vein - Temperature: central & peripheral - Urine output: - Capnography: - Blood gases & electrolytes.

Monitoring

Non-invasive - Clinical observation - ECG - NIBP - Pulse oximetry - Precordial stethoscope - Continuous airway manometry - Multiple site temperature measurement Invasive - Volumetric urine collection - Art. catheterization - CVP - PAC - TEE

Inraoperative management

The goals of Intraoperative management

- Prophylaxis against Subacute bacterial endocarditis .

- Prophylaxis against Air bubble embolism .

- Hemodynamic management. PVR SVR Contractility

Air bubble precautions

- Check and remove all air bubbles from IV tubing, injection ports, and stopcocks - Connect the IV tubing to the venous cannula while there is a free flowing IV fluid and blood.

- Before IV injection into the cannula, small amount if fluid is injected into the hub of the cannula.

Air bubble precautions

Aspiration before injection to clear any air.

Hold the syringe upright to keep the bubbles away.

Do not inject the last milliliters from the syringe.

Do not leave the central line open to air.

N2O is better avoided.

Hemodynamic management

Left to right shunts: ( pulmonary blood flow)

- The aim is to prevent

:

in SVR in PVR

Avoid vasodilators high FiO 2 hypocapnea and alkalosis

contractility

-

Right to left shunts: ( pulmonary blood flow) The aim is to prevent

:

in SVR in PVR contractility

Avoid Sympathetic stimulation .

low FiO acidosis 2 hypercapnea Avoid N2O

Anesthetic Management

Induction

- Aim: to preserve

- Method:

● ●

SVR

&

PVR

Inhalational: Sevoflurane I.V.: ketamine 2 mg/kg + fentanyl 2-3 μg/kg+ Pancuronium 0.1 mg/kg

- Antibiotic Prophylaxis:

- Intubation: Oral/ Nasal (postoperative) - Corticosteroids: decrease systemic inflammatory response

The effect of shunt on the speed of induction of anesthesia :

- In patients with a

right-to-left shunt :

Inhalation induction is prolonged .

Intravenous induction is more rapid .

- In patients with

left-to-right shunting

, the speed of inhalation or intravenous induction is not changed .

Factors Affecting PVR

Factors Increasing: - PEEP - High airway pressure Atelectasis,hypoxia ,hypercarbia - Acidosis - Catecholamine -High hematocrite Factors Decreasing: - No PEEP - Low airway pressure - High FiO2, hypocarbia - Alkalosis - Vasodilators - Low hematocrite - Nitric oxide

Anesthetic Management

Maintenance

- Patient with Poor Myocardium:

- Narcotic based....Extubation not advisable

- Patient with Good Myocardium:

- Inhalational (isoflurane, sevoflurane)

- Most Stressful Situations:

- Skin incision - Sternotomy - Major vessels cannulation (Aorta, SVC,IVC)

Choice of anesthetic Regimen

● Development of anesthetic regimen is based on various factors such as presence and direction of shunts , arrhythmia , pulmonary HF, circulation, and lowering or maintenance of PVR

Choice of Anesthetic Agent

Intravenous anesthetics Volatile anesthetics Muscle relaxants -

• Ketamine : No change in PVR in children when airway maintained & ventilation supported

Sympathomimetic effects help maintain HR, SVR, MAP and contractility Greater hemodynamic stability in hypovolemic patients Copious secretions (laryngospasm)

• Etomidate : Induction dose of 0.3mg/kg

PVR, pulmonary blood flow, PHT or

 

no change in mean pulmonary artery pressure and myocardial function

• Propofol : decrease in SBP and SVR, and increase in SBF in all patients, whereas HR ,PAP, PBF

remained unchanged

• OPIOD: Excellent induction agents in very sick children No cardiodepressant effects if

bradycardia avoided Fentanyl 15-25 µ g/kg IV , Sufentanil 5-20 µ g/kg IV

• Barbiturates : Not recommended in patients with severe cardiac reserve

Choice of Anesthetic Agent (Cont.)

- Desflurane



Pungent ,



PAP and



PVR, Less myocardial depression than Halothane



HR ,



SVR - Halothane

 

PBF not affecting PVR, Depresses myocardial function, alters sinus node function, sensitizes myocardium to catecholamines - Isoflurane leads to

 

Pungent

, 

SVR →



MAP ,



PAP not affecting PVR, Less myocardial depression than Vasodilatation HR which can lead to



CI - Sevoflurane with



Less myocardial depression than Halothane, more



isoflurane, No



HR, Mild



in PAP compared SVR, Can produce diastolic dysfunction - Nitrous oxide



At 50% concentration does not affect PVR and PAP in children Avoid in children with limited pulmonary blood flow, PHT or



myocardial function

Neuromuscular Blocking Drugs

Depolarizing

- Succinylcholine in pediatric

controversial is - If used should be with atropine, to avoid associated brady cardia or sinus arrest - also if used with potent narcotic atropine should be used avoid severe to bradycardia in children with



CR Nondepolarizing - Atracuruim and vecronium: have few cardiovascular side effects in children when given in recommended doses.

- Pancuronuim if given slowly doesn't produce HR or BP changes. if given as bolus doses it can produce tachycardia , ↑BP (through sympathomimetic effect ) -Cisatracuruim and Rocuroinuim: safe

Anestheia of Fallot patient:

- The aim is to prevent intraoperative cyanotic spells. - Avoid prolonged fasting - Heavy sedative premedication.

- Intravenous induction.

- Ketamine, Fentanyl, Pancronium, Halothane.

- Adequate intravascular volume.

- Avoid systemic vasodilatation.

- Adequate anesthetic depth to avoid sympathetic stimulation.

Management of intra operative cyanotic spells in Fallot patient

- Direct abdominal or aortic compression - IV vasoconstricror as ephedrine, phenylephrine, or dopamine - IV fluid.

- Deep level of anesthesia.

- Beta adrenergic blockers as osmolol or propranolol

REGIONAL ANESTHESIA &ANALGESIA

• Considerations :

- Coarctation of aorta considerations - Childern with chronic cyanosis



coagulation abnormality risk of - VD : which can: 1- be hazardous in patients with significant AS or left-sided obstructive lesions 2- Cause



oxyhemoglobin saturation in R-L shunts

Postoperative Anesthetic Management

- Supplemental O 2 and maintain patent airway.

- In patients with single ventricle titrate SaO 2 Higher oxygen sat. can  PVR  PBF   to 85%. SBF   Pain  catech. which can affect VR and shunt direction Pain  infundibular spasm in TOF obstruction  acidosis and death  RVOT cyanosis, hypoxia, syncope, seizures,  Anticipate conduction disturbances in septal defects

Remember

Management of

- Acute hypertensive pulmonary crisis: -

Ventilatory manipulation: reduce PVR (PaO 2 , PaCO 2 , PH, Lung volumes) Drugs: Milrinone, Isopril, PgE 2

Remember

Management of

- Intraoperative Cyanotic Spells

-Increase S.V.R.: by direct aortic compression ± (phenylephrine, ephedrine

…

..) -Reduce infundibular obstruction by

ß -Blockers

vasopressor (esmolol, propranolol

…

), OR

Halothane

-Deepen the level of anesthesia.

-Adequate hydration (ample fluid and decrease viscosity)

SUMMARY

- Familiarity with the CHD pathophysiology, adequate preoperative preparation, choice of monitors, induction, maintenance , emergence from anesthesia, and plans for the postoperative period to avoid major problems in anesthetic management - A wide variety of anesthetic regimens is used for patients with congenital heart disease (CHD) undergoing cardiac or non-cardiac surgery, or other diagnostic or therapeutic procedures. The goal of all of these regimens is to produce anesthesia or adequate sedation, while preserving systemic cardiac output and oxygen delivery