Anesthesia+CHD+Non+Cardiac+Surgery

7/30/2019 Anesthesia+CHD+Non+Cardiac+Surgery

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Anesthesia for noncardiac surgery in

children with congenital heart disease

Sheila Espina-Bertoso MD, DPBA

University of the Philippines-PGH


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Introduction

Decades of advancement in diagnostic and interventional

cardiology, surgical techniques, cardiopulmonary bypass,

anesthetic management, and critical care have dramatically

altered the natural history of congenital heart disease(CHD).

This resulted to a decrease in morbidity and mortality inaffected children and improved quality of life.


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Introduction

Anesthesiologists will encounter children with CHD for

elective non-cardiac surgery at one of three stages:

Unpalliated

Partially palliated

Completely palliated

ASD and PDA only congenital lesions

that can be truly corrected


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Increase in life expectancy leads to increased survival

rates

In some cases, children may require noncardiac surgery

before undergoing procedures to repair their cardiovascular

pathology.

Introduction


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Objective

Review general principles of anesthetic practice with afocus on preoperative assessment, intraoperative

management, and postoperative care for children with CHD

having noncardiac surgery.


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Pre-operative Assessment

50% Dx by 1st week of life; rest by 5 years

Childs diagnosis & current medical condition will determinepreoperative evaluation

Understand the anatomic and hemodynamic function ofchilds heart

Discuss case with pediatrician and cardiologist

Review diagnostic & therapeutic interventions

Above will estimate disease severity and help formulateanesthetic plan


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Preoperative Assessment

Gather information regarding the nature of the

cardiovascular disease and prior therapeutic interventions.

Determine functional status.

The history and physical examination, in addition to the

laboratory data and ancillary tests provide complementaryinformation.


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Preoperative Assessment

Based on this clinical assessment and consideration of the

major pathophysiologic consequences, a systematic,

detailed, organized plan should be formulated for

anesthetic and perioperative management.


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History and Physical Examination

History should focus on the status of the cardiovascular

system.

Relevant information includes

the type of CVD and comorbid conditions

medications

allergies

prior hospitalizations, surgeries, anesthetic

experiences, and complications elective cases.


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Symptomatology

tachypnea, dyspnea, tachycardia, dysrhythmias, and

fatigue should be sought.

feeding difficulties and diaphoresis may represent

significant symptoms in infants

decreased activity level orexercise intolerance may be

of concern in older children palpitations, chest pain, and syncope should be

characterized.


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Should include an assessment of growth and development

History ofrecent illnesses such as respiratory infections orpulmonary disease


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Physical Examination


weight and height

vital signs: HR, RR, O2 sat, BP.ex1: In general, children who have undergone definitive procedures

should be expected to have normal to near-normal SpO2(95%).After

palliative interventions, SpO2 values typically range between 75% and

85%.

ex2: For those aortic arch obstruction or has had any systemic-to-

pulmonary shunt, upper and lower extremity as well as right and left

upper extremity blood pressure and palpation of the quality of pulses

should be documented.


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Airway

General appearance

- child's level of activity- breathing pattern

- level of distress and presence of cyanosis

Respiratory evaluation

- quality of the breath sounds

- the presence or absence of labored breathing,

- intercostal retractions, wheezing, rales, or rhonchi..


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Cardiac Examination

assessment of heart sounds, pathologic murmurs, and

gallop rhythms

presence of a thrill, representing a palpable murmur,

should be noted

GI Examination- Hepatosplenomegaly


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Extremities should include examination of pulses, overall

perfusion, capillary refill, cyanosis, clubbing, and edema.

Noncardiac anomalies or pathology that may affect

anesthetic care (e.g., a specific syndrome complex, a

potentially difficult airway, gastroesophageal reflux) should

be noted.


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Ancillary Studies and Laboratory Data

In cyanotic children, CBC provides the determination of

polycythemia, microcytic anemia, and thrombocytopenia.

Prothrombin time, partial thromboplastin times, and

international normalized ratio (INR) provide an indication of

clotting ability

In those receiving diuretic therapy, digoxin, or angiotensin-

converting enzyme inhibitors, the determination of serum

electrolytes may be useful.


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Blood typing and crossmatching

A recent ECG should be reviewed for changes from priorstudies.

Exercise tolerance test or treadmill study


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Review of a recent chest Xray, including a lateral view,

provides information regarding cardiac size, chamber

enlargement, and pulmonary vascularity.

Recent echocardiogram, cardiac catheterizations,

electrophysiologic procedures, and magnetic resonance

imaging should be reviewed.


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Goal of Pre-operative Evaluation

The goals of the preoperative evaluation is to obtain the

most diagnostic information with the fewest tests and theleast risk, discomfort, and expense to the child.


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Intraoperative Management

Premedication

Should be routine.

This facilitates parental separation, entry into the operating

room, placement of monitors, and induction of anesthesia.

Commonly used premedications include oral or intravenous

benzodiazepines, opioids, and small amounts of hypnotic

agents.


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Premedication

a) Omit for infants < six months of age

b) Administer under direct supervision of Anesthesiologist inpreoperative facility

c) Oxygen, ventilation bag, mask and pulse oximetryimmediately available

d) Oral Premedication

Midazolam 0.25 -1.0 mg/kg

Ketamine 2 - 4 mg/kg

Atropine 0.02 mg/kg


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Premedication

e) IV Premedication

Midazolam 0.02 - 0.05 mg/kg titrated in small

increments

f) IM Premedication

Uncooperative or unable to take orally

Ketamine 1-2 mg/kg

Midazolam 0.2 mg/kg

Glycopyrrolate or Atropine 0.02 mg/kg


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Intravenous Access

To secure a good intravenous access is mandatory for administration

of fluids and medications during anesthetic care.


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Intravenous Access

Regarding:

Size of the intravenous catheter

Central venous access

Air in the intravenous infusion tubing.


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Emergency Drugs

In view of the potential for hemodynamic instability in some

children with CHD that may occur at any time, drugs for

emergency situations should be prepared or immediately

available to the anesthesiologist.


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Monitoring

Basic monitoring involves observation of the child, including

skin color, capillary refill, respiration, pulse palpation,

events on the surgical field, and color of shed blood.

Standard noninvasive monitors

blood pressure

electrocardiography (5-lead) pulse oximetry

capnography

temperature monitoring


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Monitoring

Electrocardiography

An ECG is used to monitor heart rate, cardiac rhythm, and

ST-segment analysis. Usually one or multiple leads are

displayed.

Most systems use two leads: standard lead II and lead V5.


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Monitoring

Pulse Oximetry

Placement is often well tolerated

One of the earliest monitors applied during anestheticinduction.

Indicate the adequacy of peripheral perfusion and cardiac

output.[
http://www.expertconsultbook.com/expertconsult/b/linkTo?type=bookPage&isbn=978-1-4160-3134-5&eid=4-u1.0-B978-1-4160-3134-5..50025-1--bib61&appID=NGEhttp://www.expertconsultbook.com/expertconsult/b/linkTo?type=bookPage&isbn=978-1-4160-3134-5&eid=4-u1.0-B978-1-4160-3134-5..50025-1--bib61&appID=NGE


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Monitoring

Capnography

To confirm proper placement of the ETT

To assess adequacy of ventilation

To recognize certain pathologic conditions such as

bronchospasm, airway obstruction, and malignant

hyperthermia.


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Monitoring

Temperature Monitoring

Watch out for hypothermia

This may influence oxygen delivery (increased oxygen

consumption) and emergence from anesthesia, cause

detrimental changes in hemodynamics, and affect

hemostasis.


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Monitoring

Urinary Output Measurements

Useful index of the adequacy of renal perfusion and cardiac

output esp during cases involving major fluid shifts or bloodloss, or long surgical procedures.


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Monitoring

Precordial stethoscope can be extremely helpful to

monitor for changes in heart tones that may suggest

early hemodynamic compromise.

Invasive monitoring (A-line) may be needed depending

on the level of monitoring required is influenced by the

child's cardiovascular pathology, clinical condition andfunctional status, and the complexity and duration of the

surgery or procedure being performed.


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Monitoring

PDA

Pulse oximetry right hand to measure pre-ductal

oxygenation

2nd probe on toe to measure post-ductal oxygenation

COARCTATION OF AORTA

Pulse oximeter on right upper limb

Pre and post - coarctation blood pressure cuffs should

be placed


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Anesthetic Technique

No specific formula or recipe.

The anesthetic techniques and agents used for a particular

situation should be selected in consideration of the

procedure to be performed

the child's disease process and functional status

factors such as age, physical characteristics, and

preferences of the anesthesiologist must be taken intoconsideration.


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Anesthetic Technique

The primary goals of anesthetic management with respect

to the cardiovascular system are

to optimize systemic oxygen delivery

maintain ventricular function within expected parameters

for the individual patient

ensure the adequacy of cardiac output.

always keep in mind a potential decreasedcardiovascular reserve and reduced tolerance for

perioperative stress.

to do a carefully titrated anesthetic, regardless of the

specific agents.


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Anesthetic technique

General Anesthesia

Advantage

widely accepted

ease of application

certainty of effect

the appropriate choice for most children undergoing

noncardiac surgery


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General Anesthesia

DISADVANTAGES

- a greater potential for wide fluctuations in the

hemodynamics

- prolonged recovery period.


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Regional Anesthesia

Demonstrated to be safe and effective in children with CHD

ADVANTAGES

effect is limited to the surgical site

decreased number of systemic medications

potentially shorter overall recovery period

a more pleasant experience for the child.

may be used for post-op pain mangement


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Regional Anesthesia

DISADVANTAGE

Its use is limited in small children and may not always be

effective.

There is also the potential for hemodynamic compromise,

particularly in hypovolemic children or those with a fixed cardiac

output, and is contraindicated in those with coagulation defects.


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Inhalational Agents

Halothane was considered for many decades the primary

agent for inhalation induction in children in combination with

oxygen and nitrous oxide.

However, with the introduction of sevoflurane in the mid

1990s, it has replaced halothane for induction of anesthesia

in many centers.


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Inhalational Agents

The safety and efficacy of halothane vs sevoflurane in

infants and children with CHD during cardiac surgery.

Sevoflurane provides better hemodynamic stability

minimal impact on myocardial performance

advocated as the preferred anesthetic for children withheart disease.


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Inhalational Agents

NITROUS OXIDE

Enlarge intravascular air emboli

May cause microbubbles and macrobubbles to expand

obstruction to blood flow in arteries and capillaries

In shunts, potential for bubbles to be shunted into systemic

circulation


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IM & IV ANESTHETICS

KETAMINE No change in PVR in children when airway maintained &

ventilation supported

Sympathomimetic effects help maintain HR, SVR, MAPand contractility

Greater hemodynamic stability in hypovolemic patients

Increases SVR, not recommended for L-R shunt CHD

Copious secretions laryngospasm atropine orglycopyrrolate


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IM & IV ANESTHETICS

KETAMINE

Relative contraindications may be coronary insufficiencycaused by:

anomalous coronary artery severe critical AS

hypoplastic left heart syndrome with aortic atresia

hypoplasia of the ascending aorta Above patients prone to VF d/t coronary insufficiency d/tcatecholamine release from ketamine


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IM & IV ANESTHETICS

IM Induction with Ketamine:

Ketamine 5 mg/kg

Succinylcholine 5 mg/kg or Rocuronium 1.5 2.0 mg/kg

Atropine or Glycopyrrolate 0.02 mg/kgIV Induction with Ketamine:

Ketamine 1-2 mg/kg

Succinylcholine 1-2 mg/kg or Rocuronium 0.6-1.2 mg/kg

Atropine or Glycopyrrolate 0.01 mg/kg


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IM & IV ANESTHETICS

OPIOIDS & BENZODIAZEPINE

Excellent induction agents in very sick children

Blunt the stress response in the pulmonary circulation

elicited by airway manipulations and at the same timeprovide sedation and amnesia.

No cardiodepressant effects if bradycardia avoided

Fentanyl 25-100 g/kg IV

Midazolam 0.05-0.1 mg/kg


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IM & IV ANESTHETICS

ETOMIDATE

CV stability

0.3 mg/kg IV

Pain on injection & myoclonic movements

THIOPENTAL & PROPOFOL

Not recommended in patients with severe cardiac

defects In moderate cardiac defects:

Thiopental 1-2 mg/kg IV or Propofol 1-1.5 mg/kg IV

Patient euvolemic


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Induction of Anesthesia

Techniques:

1. Intravenous: preferred technique because of greater

margin of safety

2. Inhalational: should be carefully titrated, but generally safe

even with patients with moderate hemodynamic issues

3. IM: Ketamine: uncooperative, devt delayed px

4. Intranasal, Rectal and Subcutaneous: less common


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Anesthetic Management

ANESTHESIA INDUCTION

Myocardial function preserved IV or inhalational

techniques suitable

Severe cardiac defects IV induction

Modify dosages in patients with severe failure


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Maintenance of Anesthesia

Inhalation or intravenous technique.

A combination of inhalational and intravenous anesthetics

(opioid and muscle relaxant) is frequently used.

The same inhalational agent administered for induction

may be continued or a different anesthetic or technique

may be selected for maintenance.


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Emergence

Most children undergoing noncardiac surgical interventions

are expected to awaken immediately at the completion of

the procedure .

This usually involves reducing and then discontinuing

intravenous or inhalational anesthetics, antagonizing

neuromuscular blockade, and removing the endotrachealtube, if present.

l f f


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Classification of CHD

A. L-R shunt

B. R-L Shunt

C. Complex Shunts

D. Obstructive Lesions


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A. L-R Shunts

L - R SHUNTS INCLUDE :

ASD 7.5% of CHD

VSD COMMONEST CHD 25%

PDA 7.5% of CHD

Common in premature infants

ENDOCARDIAL CUSHION DEFECT - 3%

Often seen with trisomy 21

AORTOPULMONARY WINDOW


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L-R Shunts

L R SHUNTS

Defects connecting arterial & venous circulation

SVR > PVR PBF

pulmonary blood flow pulmonary congestion

CHF

Long standing L-R shunts PHT

PVR > SVR R-L shunt Eisenmengers syndrome

V


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SVR?

Systemic Vascular Resistance

Systemic vascular resistance (SVR) refers to the resistance

to blood flow offered by allof the systemic vasculature,

excluding the pulmonary vasculature.

SVR = (MAP - CVP) CO
http://www.cvphysiology.com/Blood%20Pressure/BP019.htmhttp://www.cvphysiology.com/Blood%20Pressure/BP019.htm


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VENTRICULAR SEPTAL DEFECT

h d


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Anesthetic Considerations:

L - R SHUNTS :

Continuous dilution in pulmonary circulation

may onset time of IV agents

Speed of induction with inhalation agents

not affected unless CO is significantly

reduced

Degree of RV overload and/or failureunderappreciated careful induction

h d


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Anesthetic Considerations

L-R SHUNTS :

GOAL = SVR and PVR L-R shunt

PPV & PEEP increases PVR Ketamine increases SVR

Inhalation agents decrease SVR

h


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B. R-L Shunts

Defect between R and L heart

PVR> SVR

Resistance to pulmonary blood flow PBF

hypoxemia and cyanosis

Goal: Increase SVR

A h i id i


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R-L SHUNTS :

GOAL : PBF by SVR and PVR

PVR & SVR PBF

Hypoxemia/atelectasis/PEEP

Acidosis/hypercapnia

HCT

Sympathetic stimulation & surgical stimulation

Vasodilators & inhalation agents SVR

B R L Sh


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B. R-L Shunt

TOF 10% of CHD, commonest R-L shunt

PULMONARY ATRESIA

TRICUSPID ATRESIA

EBSTEINS ANOMALY

T l f F ll


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Tetralogy of Fallot

10% of all CHD

Most common R L shunt

4 anomalies:

RVOT obstruction ( infundibular, pulmonic or

supravalvular stenosis )

Subaortic VSD

Overriding aorta

RVH

T t l f F ll t


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Tetralogy of Fallot


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T t S ll (h ti i d )


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Tet Spells (hypercyanotic episodes)

Result from decreased pulmonary blood flow in children

with significant dynamic right ventricular outflow tract

obstruction.

Relatively rare during noncardiac surgery, probablybecause GA attenuates the triggers.

Factors that decrease systemic blood pressure and

systemic vascular resistance such as hypovolemia andextreme vasodilation should be avoided.

T t S ll


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Tet Spells

MANAGEMENT

1. Increasing blood volume

2. Increase inspired oxygen concentrations

3. Increase systemic vascular resistance, often with

phenylephrine

4. Lower inspiratory ventilatory pressures may also lead to

clinical improvement.5. Increase the level of sedation or anesthetic depth and -

adrenergic blockade.

T t l f F ll t


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Tetralogy of Fallot

Treatment of Hypercyanotic Spells

High FiO2 pulmonary vasodilator PVR

Hydration (fluid bolus) opens RVOT

Morphine (0.1mg/kg/dose) sedation, PVR

Ketamine SVR, sedation, analgesia PBF

Phenylephrine (1mcg/kg/dose) SVR

-blockers (Esmolol 100-200mcg/kg/min)

HR,-ve inotropy improves flow across obstructed

valve & infundibular spasm

A th ti C id ti


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PVR & SVR PBF

Hyperoxia/Normal FRC

Alkalosis/hypocapnia

Low HCT

Low mean airway pressure

Blunted stress response

Nitric oxide/ pulmonary vasodilators

A th ti C id ti


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RL SHUNTS :

Adequate hydration esp. if HCT > 50%

Inhalation induction prolonged by limited pulmonary

blood flow

IV induction times are more rapid d/t bypassing

pulmonary circulation dilution

Avoid PEEP and PPV increase PVR


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Complex Shunts


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Complex Shunts

COMPLEX SHUNTS INCLUDE :

TRUNCUS ARTERIOSUS

TRANSPOSITION OF GREAT VESSELS 5%

Arterial switch procedure > 95% survival TOTAL ANOMALOUS PV RETURN

DOUBLE OUTLET RIGHT VENTRICLE

HYPOPLASTIC LEFT HEART SYNDROME

Most common CHD presenting 1st week of life

Most common cause of death in 1st month of life

T tal A al P l ar V R t r


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Total Anomalous Pulmonary Venous Return


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Hupoplastic Left Heart Syndrome


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Hupoplastic Left Heart Syndrome

Transposition of Great Vessels


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Transposition of Great Vessels


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Double Outlet Right Ventricle


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Double Outlet Right Ventricle

Fontan Procedure


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Fontan Procedure


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Jantene Procedure


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Jantene Procedure



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COMPLEX SHUNTS : Manipulating PVR or SVR to PBF will:

Not improve oxygenation

Worsen biventricular failure

Steal circulation from aorta and cause

coronary ischemia

Maintain status quo with high dose opioidsthat do not significantly affect heart rate,

contractibility, or resistance is recommended



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COMPLEX SHUNTS :

Short procedures :slow gradual induction with low dose

Sevoflurane has least effect on +ve chronotropy & SVR

Nitrous Oxide limits FiO2 & helps prevent coronary steal& sevoflurane requirements

D Obstuctive Lesions


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D. Obstuctive Lesions

OBSTRUCTIVE LESIONS

Either valvular stenosis or vascular bands

perfusion & pressure overload of corresponding

ventricle CHF common

Right sided obstructions PBF hypoxemia andcyanosis

Left sided obstructions systemic blood flow tissue hypoperfusion, metabolic acidosis and shock



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OBSTRUCTIVE LESIONS INCLUDE : AORTIC STENOSIS

MITRAL STENOSIS

PULMONIC STENOSIS COARCTATION OF AORTA 8% of CHD

80% have bicuspid aortic valve

COR TRIATRIATUM INTERRUPTED AORTIC ARCH

Coarctation of Aorta


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Coarctation of Aorta

Interuption of Aortic Arch


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Interuption of Aortic Arch

Cor Triatiatium


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Cor Triatiatium



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OBSTRUCTIVE LESIONS

Lesions with > 50 mmHg pressure gradient + CHF

opioid technique

Optimize preload improves flow beyond lesion

Avoid tachycardia myocardial demand & flow

beyond obstruction

Inhalation agents -ve inotropy & decrease SVRworsens gradient & flow past obstruction



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Postoperative Management


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Children with CHD are very susceptible to:

i. Deleterious effects of hypoventilation

ii. Mild decreases in oxyhemoglobin saturation

Therefore, give supplemental O2 and maintain patent

airway

In patients with single ventricle titrate SaO2 to 85%.

Higher oxygen saturations can PVR PBFsystemic blood flow



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Avoid significant hypoventilation during this time because

this may negatively affect pulmonary vascular tone and

overall hemodynamics in vulnerable children.

Analgesia is very important postoperatively Pain catecholamines which can affect vascular

resistance and shunt direction

Pain

infundibular spasm in TOF

RVOT obstruction cyanosis, hypoxia, syncope, seizures, acidosis and

death

Anticipate conduction disturbances in septal defects



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Thank You!


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Documents

Anesthesia+CHD+Non+Cardiac+Surgery