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Emergencies in pediatric Emergencies in pediatric cardiologycardiology

OutlinesOutlines

Cardiogenic shockCardiogenic shock

Approach to a cyanotic neonateApproach to a cyanotic neonate

ArrhythmiasArrhythmias

• Brady arrhythmiasBrady arrhythmias

• TachyarrhythmiasTachyarrhythmias

Cardiogenic ShockCardiogenic Shock

severe cardiac dysfunction before or after severe cardiac dysfunction before or after cardiac surgerycardiac surgery

septicemiasepticemia

severe burns severe burns

anaphylaxisanaphylaxis

cardiomyopathycardiomyopathy

myocarditismyocarditis

myocardial infarction or stunningmyocardial infarction or stunning

CCentral nervous system disordersentral nervous system disorders

Cardiogenic ShockCardiogenic Shock

CardiomyopathyCardiomyopathy

ArrhythmiasArrhythmias

Mechanical abnormalityMechanical abnormality

Obstructive disorderObstructive disorder

TreatmentTreatment

Treatment is aimed at reinstitution of Treatment is aimed at reinstitution of adequate cardiac output and peripheral adequate cardiac output and peripheral perfusion to prevent the -untoward effects perfusion to prevent the -untoward effects of prolonged ischemia on vital organs, as of prolonged ischemia on vital organs, as well as management of the underlying well as management of the underlying cause.cause.

Cardiac output in turn is dependent Cardiac output in turn is dependent on two cardiac factorson two cardiac factors

1) heart rate (HR) and 1) heart rate (HR) and

2) stroke volume (SV).2) stroke volume (SV).

As children are "heart rate dependent", As children are "heart rate dependent", the heart rate is the single most important the heart rate is the single most important vital sign when determining shock.vital sign when determining shock.

Stroke volume is the second determinant of Stroke volume is the second determinant of cardiac output, and is dependent on three cardiac output, and is dependent on three

factors:factors:1) preload (intravascular volume/blood often called 1) preload (intravascular volume/blood often called "venous return"), (the fuel), "venous return"), (the fuel), 2) myocardial contractility (heart muscle function), (the 2) myocardial contractility (heart muscle function), (the pump), and pump), and 3) afterload (systemic vascular resistance) (the pipes). 3) afterload (systemic vascular resistance) (the pipes). Children are particularly dependent upon adequate Children are particularly dependent upon adequate intravascular volume, and when volume depleted, they intravascular volume, and when volume depleted, they peripherally vasoconstrict to maintain stroke volume. The peripherally vasoconstrict to maintain stroke volume. The myocardium in infants is "stiff" and plays little role in myocardium in infants is "stiff" and plays little role in increasing cardiac output. Therefore, the heart rate must increasing cardiac output. Therefore, the heart rate must increase in order to maintain adequate circulatory increase in order to maintain adequate circulatory function. Rememberfunction. Remember C.O.=H.R. x S.VC.O.=H.R. x S.V

PreloadPreload

Optimal filling pressure is variable and Optimal filling pressure is variable and depends on a number of extracardiac depends on a number of extracardiac factors including ventilatory support with factors including ventilatory support with high positive end-expiratory pressure and high positive end-expiratory pressure and intra-abdominal pressure. intra-abdominal pressure.

The increased pressure necessary to fill a The increased pressure necessary to fill a relatively noncompliant ventricle should relatively noncompliant ventricle should also be consideredalso be considered

PreloadPreload

The mean difference between CVPs The mean difference between CVPs measured from the central and peripheral measured from the central and peripheral catheters was 8 ± 4 cm H2O. catheters was 8 ± 4 cm H2O.

The linear regression equation showed :The linear regression equation showed :

CVP = 0.32 PVP + 3.8 (r = 0.67; p<0.005). CVP = 0.32 PVP + 3.8 (r = 0.67; p<0.005).

H. Amoozgar, N. Behniafard, M. Borzoee ,G. H. Ajami. Correlation Between Peripheral and Central Venous Pressures in Children with Congenital Heart Disease. Pediatr Cardiol (2008) 29:281–284

ContractilityContractility

Dopamine, epinephrine, and dobutamine Dopamine, epinephrine, and dobutamine improve cardiac contractilityimprove cardiac contractility

The use of cardiac glycosides to treat The use of cardiac glycosides to treat acute low cardiac output states should be acute low cardiac output states should be avoidedavoided

AfterloadAfterload

Patients in cardiogenic shock may have a Patients in cardiogenic shock may have a marked increase in systemic vascular marked increase in systemic vascular resistance resulting in high afterload and resistance resulting in high afterload and poor peripheral perfusionpoor peripheral perfusion

Milrinone & nitroprusaidMilrinone & nitroprusaid

Blood pressure Blood pressure measurement in measurement in

neonatesneonates

Blood pressure measurement in neonates

Blood pressure measurement in neonates

Blood pressure measurement in neonatesBlood pressure measurement in neonates

the measured BP is 9 mm Hg higher than the measured BP is 9 mm Hg higher than pulse method.pulse method.

In 86-92% of neonate the measured BP by In 86-92% of neonate the measured BP by pulse had only 10 mm Hg difference with pulse had only 10 mm Hg difference with BP by pulse oximetry.BP by pulse oximetry.

H. Amoozegar, M.Rastegar . Comparison of neonatal blood pressure measurement by pulse-oximetry and conventional method (Pulse) Iran J Pediatr, Vol 16, No 3, Sep 2006

StagesStages

Disturbance of perfusionDisturbance of perfusion

End organ damageEnd organ damage

Irreversible shockIrreversible shock

DeathDeath

Evaluation and initial Evaluation and initial management of cyanotic management of cyanotic

heart disease in the heart disease in the newbornnewborn

Cyanosis Cyanosis

HISTORYHISTORY

Family historyFamily history

Prenatal testingPrenatal testing

Perinatal historyPerinatal history

PHYSICAL EXAMINATIONPHYSICAL EXAMINATION

Vital signsVital signs

Second heart soundSecond heart sound

MurmurMurmur

HepatomegalyHepatomegaly

LABORATORY STUDIESLABORATORY STUDIES

Complete blood countComplete blood count Sepsis evaluationSepsis evaluation Chest radiographChest radiograph ElectrocardiogramElectrocardiogram Oxygen saturationOxygen saturation Arterial blood gasArterial blood gas Hyperoxia testHyperoxia test EchocardiographyEchocardiography

INITIAL MANAGEMENTINITIAL MANAGEMENT

General approachGeneral approach

AntibioticsAntibiotics

Prostaglandin E1Prostaglandin E1

Cardiac catheterizationCardiac catheterization

Hypercyanotic Episodes and Hypercyanotic Episodes and SquattingSquatting

severe and often prolonged decrease in arterial severe and often prolonged decrease in arterial saturationsaturation

The cyanosis is a result of an acute, substantial The cyanosis is a result of an acute, substantial increase in right-to-left shunting owing to a change increase in right-to-left shunting owing to a change in the ratio between pulmonary and systemic in the ratio between pulmonary and systemic vascular impedance.vascular impedance.

They tended to occur more commonly in patients They tended to occur more commonly in patients with iron deficiency anemiawith iron deficiency anemia

changes in the degree of subpulmonic obstructionchanges in the degree of subpulmonic obstruction

TreatmentTreatment

Knee chest positionKnee chest position

O2 2L/MinO2 2L/Min

Hydration 20 cc/KgHydration 20 cc/Kg

Morphine 0.2 mg/KgMorphine 0.2 mg/Kg

Bicarbonate 1 meg /KGBicarbonate 1 meg /KG

Propranolol 0.01-0.1 mg/KGPropranolol 0.01-0.1 mg/KG

PhenylephrinePhenylephrine

ArrhythmiasArrhythmias

Brady arrhythmiaBrady arrhythmia

Abnormalities of impulse propagation Abnormalities of impulse propagation and/or inhibitory neural influence in the AV and/or inhibitory neural influence in the AV conduction system may result in conduction system may result in abnormalities including intra-atrial block, abnormalities including intra-atrial block, block within the AV node, block within the block within the AV node, block within the His, or aberrant ventricular conduction His, or aberrant ventricular conduction owing to block within one of the owing to block within one of the specialized intraventricular fascicles.specialized intraventricular fascicles.

ManagementManagement

Treatment for sinus node dysfunction Treatment for sinus node dysfunction depends on symptoms, which may include depends on symptoms, which may include syncope, exercise intolerance, and/or syncope, exercise intolerance, and/or cardiac dysfunction aggravated by loss of cardiac dysfunction aggravated by loss of AV synchrony, all of which are treated with AV synchrony, all of which are treated with pacing. pacing.

Isoperoteranol (B1,B2 agonist)Isoperoteranol (B1,B2 agonist)

0.05-2 mac/Kg/Min0.05-2 mac/Kg/Min

PacingPacing

Supraventricular tachycardias Supraventricular tachycardias (SVTs)(SVTs)

categories: categories:

• re-entrant tachycardias usingre-entrant tachycardias using

an accessory pathwayan accessory pathway

• Re-entrant tachycardias without an Re-entrant tachycardias without an accessoryaccessory

• pathway, and ectopic or automatic pathway, and ectopic or automatic tachycardiastachycardias

CLINICAL MANIFESTATI0NCLINICAL MANIFESTATI0N

The heart rate usually exceeds 180 beats/min The heart rate usually exceeds 180 beats/min and may occasionally be as rapid as 300 and may occasionally be as rapid as 300 beats/minbeats/min

The only complaint may be awareness of the The only complaint may be awareness of the rapid heart rare. rapid heart rare.

ECGECG

SVT may occur in the presence of SVT may occur in the presence of unoperated congenital heart disease (Ebstein unoperated congenital heart disease (Ebstein anomaly). anomaly).

In children, SVT may be precipitated by In children, SVT may be precipitated by exposure to the sympathomimetic amines exposure to the sympathomimetic amines contained in over-the-counrer decongestantscontained in over-the-counrer decongestants

associated with abnormal hearts associated with abnormal hearts (cardiomyopathy) or with posroperative (cardiomyopathy) or with posroperative congenital heart diseasecongenital heart disease

Differentiation from sinus Differentiation from sinus tachycardiatachycardia

Differentiation from sinus tachycardia may Differentiation from sinus tachycardia may be difficult; if the rate is >230 beats/min be difficult; if the rate is >230 beats/min with an abnormal P-wave axis (a normal P with an abnormal P-wave axis (a normal P wave is positive in leads I and aVF)wave is positive in leads I and aVF)

TREATMENTTREATMENT

Vagal stimulation by submersion of the Vagal stimulation by submersion of the face in iced saline (in older children) or by face in iced saline (in older children) or by placing an ice bag over the face (in placing an ice bag over the face (in infants) may abort the attackinfants) may abort the attackTo abolish the paroxysm, older children To abolish the paroxysm, older children may be taught vagotonic maneuvers such may be taught vagotonic maneuvers such as the Valsalva maneuver, straining, as the Valsalva maneuver, straining, breath holding, drinking ice water, or breath holding, drinking ice water, or adopting a particular posture.adopting a particular posture.

PharmacologicPharmacologic

In stable patients, adenosine by rapid In stable patients, adenosine by rapid intravenous push is the treatment of intravenous push is the treatment of choice because of its rapid onset of action choice because of its rapid onset of action and minimal effects on cardiac and minimal effects on cardiac contractility.contractility.

Adenosine 0.1-0.2 mg/Kg over 1-2 Adenosine 0.1-0.2 mg/Kg over 1-2 sec(Max 0.25 Mg/Kg up to 12 Mg)sec(Max 0.25 Mg/Kg up to 12 Mg)

DC cardio versionDC cardio version

when symptoms of severe heart failure when symptoms of severe heart failure have already occurred, synchronized DC have already occurred, synchronized DC cardio version (0.5-2 W-sec/kg) is cardio version (0.5-2 W-sec/kg) is recommended as the initial managementrecommended as the initial management

maintenance therapymaintenance therapy

In patients without an antegrade In patients without an antegrade accessory accessory pathway, digoxin or propranolol is the pathway, digoxin or propranolol is the mainstay of therapy.mainstay of therapy.

In children with evidence of preexcitation In children with evidence of preexcitation (WPW syndrome) digoxin or calcium channel (WPW syndrome) digoxin or calcium channel blockers may increase the rate of blockers may increase the rate of anterograde conduction of impulses through anterograde conduction of impulses through the bypass tract and should be avoided.the bypass tract and should be avoided.

Radiofrequency ablationRadiofrequency ablation

Ventricular tachycardiaVentricular tachycardia

Ventricular tachycardia (VT) is less Ventricular tachycardia (VT) is less common than SVT in pediatric patients. common than SVT in pediatric patients.

VT is defined as at least three PVCs at VT is defined as at least three PVCs at >120 beats/min>120 beats/min

TreatmentTreatment

For patients who are hemodynamically For patients who are hemodynamically stable, intravenous amiodarone, lidocaine, stable, intravenous amiodarone, lidocaine, or procainamide are the initial drugs of or procainamide are the initial drugs of choice.choice.

Lidocaine 1 mg/Kg slowly IV *2 times 15 Lidocaine 1 mg/Kg slowly IV *2 times 15 min and then 20-50 mcg /Kg/Minmin and then 20-50 mcg /Kg/Min

ETT Dose 2-2.5* IVETT Dose 2-2.5* IV

Amiodarone 5-10 mg/Kg over 30 minAmiodarone 5-10 mg/Kg over 30 min

DC shockDC shock

when symptoms of severe heart failure when symptoms of severe heart failure have already occurred, synchronized DC have already occurred, synchronized DC cardioversion (4 J/kg) is recommended as cardioversion (4 J/kg) is recommended as the initial managementthe initial management

Unless a clearly reversible cause is Unless a clearly reversible cause is identified, electrophysiologic study is identified, electrophysiologic study is usually indicated for patients in whom VT usually indicated for patients in whom VT has developedhas developed