Cardiovascular System I. Objectives. Congenital Heart Disease: Recognition and Stabilization

Transcription

1 Cardiovascular System I Objectives Present the clinical features and emergency management of cardiovascular disorders, including: Recognize congenital and acquired heart disease. Outline management of ductal-dependent lesions. Identify patients with myocarditis. Congenital Heart Disease: Recognition and Stabilization Rapid cardiopulmonary assessment to recognize and manage life-threatening illness caused by heart disease Understand the physiology of different conditions to optimize treatment plans. 1

2 Critical Concepts Structural congenital heart disease can present in many different ways at different ages. Acquired heart disease can be subtle yet life-threatening. Case Study 1: Rapid Breathing 10-day-old infant brought to ED by mother, rapid breathing, not eating well Product of normal spontaneous vaginal delivery Spent 2 days with mother in hospital Uneventful course, including circumcision Birth weight of 3.2 kg Fussy, weak cry, grunting, nasal flaring, pale, sweaty, central cyanosis Case Study 1 (continued) Slow to breastfeed since birth Would gasp and cry after sucking for a short time. Difficulty feeding. 3 to 4 wet diapers per day No congestion, no fever No vomiting with feedings 2 yellow, seedy stools since passing meconium after birth 2

3 Initial Assessment (1 of 2) PAT: Abnormal appearance, abnormal breathing, abnormal circulation Vital signs: Heart rate 170/min, respiratory rate 70/min, blood pressure 82/40 mm Hg, temperature 37 C (rectal), oxygen saturation 90% on room air, weight 3.4 kg Initial Assessment (2 of 2) A: No evidence of obstruction B: Elevated respiratory rate and labored C: Pale, diaphoretic, tachycardic, weak pulse, cyanotic D: GCS score grossly normal but in distress and inconsolable E: No signs of head injury, fractures, or bruising Detailed Physical Examination Lung sounds equal bilaterally with rales in both bases Hyperactive precordium with a gallop rhythm Pulses weak in distal and lower extremities Distended abdomen with liver palpable 4 cm below right costal margin 3

4 Key Question What is your general impression of this patient? General Impression Impending cardiopulmonary failure (compensated shock) Cyanosis, diaphoresis Pale, tachycardia What are your initial management priorities? Management Priorities (1 of 3) ABCs Give 15 L of oxygen by nonrebreather mask or 100% oxygen by bag-mask ventilation, prepare for endotracheal intubation. Obtain intravenous access and measure blood glucose concentration. ECG and monitor rhythm on cardiac monitor Chest radiograph Administer fluid challenge: 10 ml/kg of normal saline 4

5 Management Priorities (2 of 3) Administer PGE 1 : 0.05 to 0.1 mcg/kg/min Intubate to protect against apnea and relieve stress from work of breathing. Consider furosemide (0.5 to 1 mg/kg). Sepsis work-up and then antibiotics Defer lumbar puncture. Management Priorities (3 of 3) Cardiology consultation or transfer to pediatric cardiology center emergently: Echocardiogram If blood pressure and perfusion do not improve, add inotropic agent: Dobutamine: 2 to 20 mcg/kg/min Case Discussion (1 of 2) This infant is in CHF. Poor feeding and easy fatigability Gallop rhythm and enlarged liver Diminished pulses Shock: Altered mental status, compensated shock (tachycardia, diaphoresis, respiratory distress, normal blood pressure in upper extremities) 5

6 Case Discussion (2 of 2) Possible ductal-dependent lesion: Right age for presentation of shock triggered by closure of the ductus arteriosus Measure blood pressure in 4 extremities Assess oxygenation response to supplemental oxygen Case Progression: Version 1 Blood pressure differential noted in lower extremities. Oxygenation improves to 99% with supplemental oxygen. Chest radiograph shows cardiomegaly and pulmonary edema. Echocardiogram demonstrates coarctation of the aorta. Infant improves with PGE 1 infusion, diuretics, and inotropes. Case Progression: Version 2 Oxygenation fails to improve with supplemental oxygen (remains 90%). Oxygenation declines further to <80%. Chest radiograph is nonspecific. Echocardiogram demonstrates transposition of the great vessels. Infant improves with PGE 1 infusion. Surgical intervention is scheduled. 6

7 Background: Structural Congenital Heart Disease Congenital heart disease: 5 to 8 cases per 1,000 live births Child with congenital anomaly usually does not show cardiovascular problems in utero. Changes at birth place great stress on infant s CVS Some cyanotic heart conditions are highly dependent on shunting through ductus arteriosus. Closure can be a terminal event. Clinical Features: Your First Clue Age Progressive deterioration (mild) followed by suddenly progressing to critical condition Cyanosis CHF Consider concurrent sepsis Diagnostic Studies (1 of 3) Radiology: Pulmonary hypoperfusion: pulmonic stenosis, TOF, TA CHF (if large VSD present to allow high-output failure, eg, increased right-sided flow) Some classic chest radiograph appearances (more classic if condition is permitted to worsen): TGA: Egg on side TAPVR: Snowman TOF: Boot shaped 7

8 Diagnostic Studies (2 of 3) ECG: Right axis: Normal for newborns Left axis: Hypoplastic right heart, TA, endocardial cushion defect (atrioventricular canal) ST-T changes, strain, ischemia Dysrhythmia Prolonged QT Low voltage Diagnostic Studies (3 of 3) Laboratory: Glucose: Any child in distress needs to have hypoglycemia excluded. CBC: Look for anemia, signs of sepsis. Electrolytes: Congenital adrenal hyperplasia, salt-wasting form Arterial blood gas: Hyperoxia test Fetal Circulation (1 of 2) Placenta oxygenates blood and returns to RA via inferior vena cava Preferentially shunts across foramen ovale to LA. LV ejects most oxygenated blood to carotids and coronaries. 8

9 Fetal Circulation (2 of 2) Superior vena cava returns deoxygenated blood to RA, where it mixes with oxygenated blood from the placenta. Preferentially enters RV. RV ejects into PA. No pulmonary capillary flow, so PA blood is shunted into the descending aorta via the ductus arteriosus. Coarctation of the Aorta: Version 1 (1 of 2) Coarctation of the Aorta: Version 1 (2 of 2) 9

10 TGA: Version 2 Differential Diagnosis: What Else? (1 of 2) Other cyanotic and acyanotic congenital structural heart disease Ductal-dependent coarctation Hypothermia Sepsis TORCH Differential Diagnosis: What Else? (2 of 2) Congenital adrenal hyperplasia Hypoglycemia Shaken infant syndrome/intracranial lesion Catastrophic gastrointestinal process (eg, volvulus) 10

11 Normal CVS Function Represented by vital signs (oxygen saturation included) Factors affecting cardiac output (perfusion): Heart rate Stroke volume Contractility Vascular resistance Children younger than 8 years predominantly increase their heart rate to increase cardiac output (unable to increase stroke volume until older than 10 years). Normal Vital Signs For Age Heart Rate, Resp Rate, BP (systolic), /min /min mm Hg Newborn month months months year years years years years years years years Transition from Fetal Circulation Placental circulation is interrupted at birth: Increase in systemic arterial blood pressure Spontaneous respirations Decreased pulmonary vascular resistance, increasing pulmonary blood flow Foramen ovale closes. Ductus arteriosus reverses and begins to close. This initial rapid change slows during first 24 hours of life. 11

12 CHD Cyanotic: Refractory to oxygen Right to left shunting Some lesions (eg, TGA) are highly dependent on a shunt (VSD, PDA) Cyanosis usually presents shortly after birth as ductus begins to close. Cyanotic CHD 5 T s: Truncus arteriosus TOF TGA TA TAPVR Severe aortic stenosis Hypoplastic left heart Severe coarctation of the aorta TOF 1. Pulmonic stenosis 2. Overriding aorta 3. VSD 4. Right ventricular hypertrophy Right-to-left shunting through VSD dependent on severity of pulmonic stenosis 12

13 TA RV is hypoplastic. Right-to-left shunt through ASD and VSD or atrioventricular canal TAPVR Cyanosis Respiratory disorder Hemoglobin disorder Acrocyanosis (normal newborns): Cold stress and peripheral vasoconstriction Generalized or central cyanosis often due to cyanotic congenital heart disease. Often worsened by crying. 13

14 Central Cyanosis vs Acrocyanosis Hyperoxia Test Administer 100% oxygen. Significant increase in Pao 2 seen with pulmonary and hemoglobin disorders. In CHD, Pao 2 will not increase or it will increase slightly. Deoxygenated blood bypasses lungs and goes directly to left side of heart, diluting the fully oxygenated blood coming from lungs with deoxygenated blood. CHD Increased pulmonary vascularity: TAPVR Truncus arteriosus TGA Other complex lesions without pulmonic stenosis Decreased pulmonary vascularity: TOF Ebstein anomaly Hypoplastic right heart, TA Complex lesions with pulmonic stenosis 14

15 Prostaglandin E 1 Keeps the ductus open 0.05 to 0.1 mcg/kg/min with an increase to 0.2 mcg/kg/min in several minutes Adverse effects: Apnea, pulmonary congestion, fever, hypotension, seizures, and diarrhea Consider elective intubation Noncyanotic CHD May present with CHF or heart murmurs heard during physical examination Left-to-right shunts Excess pulmonary vascularity ASD, VSD, PDA Obstructive lesions Aortic stenosis, coarctation of the aorta, mitral stenosis, pulmonic stenosis Clinical Features CHF: Tachypnea, tachycardia, diaphoresis, decreased feeding, hepatomegaly, murmurs, gallop rhythms Decreased activity or poor sleeping with respiratory distress 15

16 Diagnostic Studies Chest radiograph: Cardiomegaly, pulmonary vascular congestion ECG: Abnormal axis, ST-segment changes, chamber enlargement Echocardiogram: Definitive anatomical diagnosis, degree of congestive heart failure (chamber sizes, contractility) Management of CHF Give oxygen, assisted ventilation if needed. Elevate head and shoulders 45 Monitors, pulse oximetry Obtain intravenous access. Send samples to laboratory. Chest radiograph and ECG Furosemide, nitroglycerin, digoxin Inotropes (dobutamine) for signs of shock Case Study 2: Chest Pain, SOB 12-year-old boy presents with symptoms of chest pain and SOB. 5 days of cold and cough symptoms Lying around a lot and has missed 1 week of school. Usually a very active child but states that he is just too tired to play Listless, pale, breathing hard 16

17 Initial Assessment PAT: Abnormal appearance, abnormal breathing, abnormal circulation Vital signs: Heart rate 120/min, respiratory rate 44/min, blood pressure 94/65 mm Hg, temperature 37.8 C, oxygen saturation 90% on room air, increases to 100% on oxygen Initial Assessment A: Patent B: Intermittently shallow and deep; rapid respiratory rate C: Pale; pulse rapid, thready, and weak D: No focal deficits, GCS score of 15 E: No signs of injury Focused History O: Chest hurts for several days. P: Provoked by cough and exertion; short of breath whenever he gets up and walks Q: Burning, pressure R: Substernal, some radiation to shoulders S: 3 to 8 of 10 T: Pressure and SOB last almost all day, exacerbations with exertion last 15 to 30 minutes 17

18 Detailed Physical Exam Neck: Jugular venous distention supine Lungs: Diminished breath sounds with occasional end expiratory wheeze with deep breaths Cardiac: Distant heart sounds, no murmurs, S 3 gallop rhythm Abdomen: Distended with palpable spleen and liver Neurologic: No focal deficits Key Questions What is your general impression of this patient? What are your initial management priorities? General Impression Child is in respiratory distress and in cardiogenic shock. Demonstrates abnormal appearance with increased work of breathing and signs of shock. 18

19 Management Priorities ABCs Give oxygen by nonrebreather mask. Check rhythm on cardiac monitor. Obtain intravenous access. Perform blood glucose, laboratory studies. Consider reducing preload and afterload. Consider diuretic therapy. May need inotropic support. Case Discussion: Differential Diagnosis Acquired cardiac problem: Respiratory illness during winter months causing secondary myocarditis Congenital heart lesion that had been asymptomatic until this illness: Anomalous coronary artery or valvular disease Pericarditis Clinical Features: Your First Clue Consider myocarditis in any child with: Weakness SOB Chest pain Especially if associated with preceding prodromal viral illness Distant heart sounds: Silent chest Enlarged heart on chest radiograph 19

20 Diagnostic Studies: Myocarditis Radiology: Chest radiograph will reveal cardiomegaly and prominent vasculature, perhaps even pulmonary edema Laboratory: May not add much Not specific Differential Diagnosis: What Else? Pericarditis Hypertensive crisis Anomalous coronary artery and myocardial ischemia/infarction Valvular disease Structural cardiac disease (eg, VSD, ASD) Renal failure (eg, glomerulonephritis) Rheumatic fever Management: Myocarditis Gentle diuretic therapy Afterload reduction Possibly inotropic support Echocardiogram Intrinsic cardiac lesion? Muscle hypertrophy? Pericardial effusion? Decreased contractility? 20

21 Case Progression: Version 1 Chest radiograph: Cardiomegaly Echocardiogram: Poor cardiac contractility Diagnosis: Myocarditis Maintained with inotropes and pressor agents Recovered to a point that he could be discharged 2 weeks later Will be followed up closely to assess the degree to which he regains cardiac function Case Progression: Version 2 Chest radiograph: Cardiomegaly Echocardiogram: Poor cardiac contractility Diagnosis: Myocarditis Deteriorates in ED: Progressive shock Requires inotropic support Develops ventricular fibrillation, successfully shocked into a sinus rhythm Extracorporeal membrane oxygenation Myocarditis Inflammatory disease of the myocardium: Direct infection of the myocardium (eg, viral myocarditis) Toxin production (eg, diphtheria) Immune response as a delayed sequela of an infection (postviral or postinfectious myocarditis) ARF, a common type of myocarditis 21

22 ARF: Jones Criteria Major criteria: Carditis: Most commonly valvulitis Migratory polyarthritis Chorea, erythema marginatum, subcutaneous nodules Minor criteria: Fever, elevated C-reactive protein level or erythrocyte sedimentation rate, prolonged PR interval, arthralgia Need 2 major or 1 major plus 2 minor plus documented antecedent group A streptococcal infection Pericarditis Pericardial inflammation Viral vs bacterial Bacterial causes include pneumococcus, S aureus, H influenzae type B Viral most commonly coxsackievirus Cardiac tamponade possibly requiring pericardiocentesis Pericarditis: Clinical Features Chest pain Respiratory distress, CHF, or tamponade Precordial "knock" or rub (like the sound of shoes walking on snow) The classic signs include exercise intolerance, fatigue, jugular distension, lower extremity edema, hepatomegaly, poor distal pulses, diminished heart tones, and pulsus paradoxus. 22

23 Endocarditis An infection of the endothelial surface of the heart, with a propensity for the valves Increased risk in children with artificial valves and patches and patients with central catheters 90% of cases are caused by gram-positive cocci. S viridans, S aureus pneumococcus, and group A ß- hemolytic streptococci Endocarditis Clinical Features Fever Tachycardia, CHF, dysrhythmia, cardiogenic shock History of recent cardiac surgery or indwelling vascular catheter Heart murmur Petechiae, septic emboli, or splenomegaly Kawasaki Disease Vasculitis: Propensity for coronary aneurysms Aneurysms may subsequently scar, resulting in coronary stenosis (earlyonset coronary artery disease). Coronary artery thrombosis and myocardial infarction Dysrhythmia 23

24 Kawasaki Disease: Clinical Features History of fever for 5 days or more Conjunctivitis Cervical lymphadenopathy Erythematous mouth and pharynx and/or red, cracked lips and strawberry tongue Polymorphous rash Swelling of the hands with erythema of the palms The Bottom Line Assessment of congenital heart disease can be challenging. Applying assessment skills with an understanding of normal physiology and pathophysiology of cardiovascular disorders in children will assist the clinician in management. Credits Unless otherwise indicated, all photographs and illustrations are under copyright of Jones & Bartlett Learning, courtesy of Maryland Institute for Emergency Medical Services Systems, or the American Academy of Pediatrics. Slide 1: Patrick Olear / PhotoEdit, Inc. Slide 26: S Man Harun, Y Faridah, Spiral CT angiography in an infant with a hypoplastic aortic arch, Biomed Imaging Interv J 2006;2(2):e11. Slide 27: Courtesy of Loren Yamamoto, MD. From: Radiology Cases. Pediatric Emerg Med, Vol 3, Case 11, August Available online at: Accessed August 29, Slide 40A&B: Kattwinkel J, ed. Textbook of Neonatal Resuscitation. 5 th ed. Elk Grove Village, IL: American Academy of Pediatrics and American Heart Association; 2006:A. Slide 58: Courtesy of Loren Yamamoto, MD, MPH, MBA, FAAP, FACEP Slide 73: herjua/shutterstock, Inc. 24

25 25