Cardiovascular System I

1. Cardiovascular System I

2. 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.

3. 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.

4. Critical Concepts • Dysrhythmias can cause serious cardiovascular compromise. • Structural congenital heart disease can present in many different ways at many different ages. • Acquired heart disease can be subtle yet life-threatening.

5. Case Study 1:“Rapid Breathing” • 10-day-old infant is brought to ED by mother for rapid breathing and not eating well. • Product of normal spontaneous vaginal delivery • Spent 2 days with mother in hospital • Uneventful course, including circumcision • Birth weight 3.2 kg

6. 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

7. Initial Assessment (1 of 2) PAT: • Abnormal appearance, abnormal breathing, abnormal circulation Vital signs: • HR 170, RR 70, BP 82/40, T 37°C (rectal), Wt 3.4 kg, O2 sat 90% on room air

8. Initial Assessment (2 of 2) A: No evidence of obstruction B: Elevated RR and labored C: Pale, diaphoretic, tachycardia, weak pulse, cyanosis D: GCS grossly normal but in distress and inconsolable E: No signs of head injury, fractures, or bruising

9. Detailed Physical Exam • 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

10. Question What is your general impression of this patient?

11. General Impression • Impending cardiopulmonary failure (compensated shock) • Cyanosis, diaphoresis • Pale, tachycardia What are your initial management priorities?

12. Management Priorities (1 of 3) • ABCs • Give 15L O2 by nonrebreather mask or 100% O2 by BMV, or perform endotracheal intubation. • Start IV, obtain blood glucose. • ECG and monitor rhythm on cardiac monitor • CXR • Administer fluid challenge: 10 cc/kg NS

13. Management Priorities (2 of 3) • Administer prostaglandin E1 (PGE1): • 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.

14. 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 • Epinephrine: 0.1 to 1.5 mcg/kg/min

15. 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 BP in upper extremities)

16. 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 four extremities • Assess oxygenation response to supplemental oxygen

17. Case Progression: Version 1 • BP differential noted in lower extremities. • Oxygenation improves to 99% with supplemental oxygen. • CXR shows cardiomegaly and pulmonary edema. • Echocardiogram demonstrates coarctation of the aorta. • Infant improves with PGE1 infusion, diuretics, and inotropes.

18. Case Progression: Version 2 • Oxygenation fails to improve with supplemental oxygen (remains 90%). • Oxygenation declines further to <80%. • CXR is nonspecific. • Echocardiogram demonstrates transposition of the great vessels. • Infant improves with PGE1 infusion. • Surgical intervention is scheduled.

19. 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 cardiovascular system. • Some cyanotic heart conditions are highly dependent on shunting through ductus arteriosus. Closure can be terminal event.

20. Clinical Features: Your First Clue • Age • Progressive deterioration (mild) followed by suddenly progressing to critical condition • Cyanosis • Congestive Heart Failure (CHF) • Consider concurrent sepsis

21. Diagnostic Studies (1 of 3) • Radiology: • Pulmonary hypoperfusion: pulmonic stenosis, TOF, TA • CHF (if large VSD present to allow high-output failure, e.g., increased right-sided flow) • Some classic CXR appearances (more classic if condition is permitted to worsen): • TGA: Egg on side • TAPVR: Snowman • TOF: Boot shaped

22. Diagnostic Studies (2 of 3) • ECG: • Right axis (RVH): Normal for newborns • Left axis: Hypoplastic right heart, tricuspid atresia, endocardial cushion defect (AV canal) • ST-T changes, strain, ischemia • Dysrhythmia • Prolonged QT • Low voltage

23. 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 text

24. Fetal Circulation (1 of 2) • Placenta oxygenates blood and returns to right atrium (RA) via IVC. • Preferentially shunts across FO to LA. • LV ejects most oxygenated blood to carotids and coronaries.

25. Fetal Circulation (2 of 2) • Superior vena cava (SVC) 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 is shunted into the descending aorta via the ductus arteriosus.

26. Coarctation of the Aorta (1 of 2)

27. Coarctation of the Aorta (2 of 2)

28. Transposition of the Great Arteries

29. Differential Diagnosis: What Else? (1 of 2) • Other cyanotic and acyanotic congenital structural heart disease • Ductal dependent coarctation • Hypothermia • Sepsis • TORCH

30. Differential Diagnosis: What Else? (2 of 2) • Congenital adrenal hyperplasia (CAH) • Hypoglycemia • Shaken baby syndrome/intracranial lesion • Catastrophic gastrointestinal process, e.g., volvulus

31. Normal CV System Function • Represented by vital signs (O2 sat included) • Factors affecting cardiac output (perfusion): • Heart rate • Stroke volume • Contractility • Vascular resistance • Children <8 years predominantly increase their HR to increase cardiac output (unable to increase stroke volume until >10 years).

32. Normal Vital Signs For Age HR RR BP (systolic) Newborn 90-180 40-60 60-90 1 month 110-180 30-50 70-104 3 months 110-180 30-45 70-104 6 months 110-180 25-35 72-110 1 year 80-160 20-30 72-110 2 years 80-140 20-28 74-110 4 years 80-120 20-26 78-112 6 years 75-115 18-24 82-115 8 years 70-110 18-22 86-118 10 years 70-110 16-20 90-121 12 years 60-110 16-20 90-126 14 years 60-110 16-20 92-130

33. 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 closes. • This initial rapid change slows down over first 24 hours of life.

34. Cyanotic Heart Disease (CHD) • Cyanotic: Refractory to oxygen • Right to left shunting • Some lesions (e.g., TGA) are highly dependent on a shunt (VSD, PDA) • Cyanosis usually presents shortly after birth.

35. Cyanotic CHD • 5 Ts: • Truncus arteriosus • Tetralogy of Fallot (TOF) • Transposition of the great arteries (TGA) • Tricuspid atresia • Total anomalous pulmonary venous return (TAPVR) • Severe aortic stenosis • Hypoplastic left heart • Severe coarctation of the aorta

36. Tetralogy of Fallot (TOF) • Pulmonic stenosis • Aortic override • VSD • RVH • Right-to-left shunting through VSD dependent on severity of pulmonic stenosis

37. Tricuspid Atresia • RV is hypoplastic. • Right-to-left shunt through VSD

38. Total Anomalous Pulmonary Venous Return (TAPVR)

39. 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.

40. Central Cyanosis vs. Acrocyanosis

41. Hyperoxia Test • Administer 100% oxygen. • Significant increase in PaO2 seen with pulmonary and hemoglobin disorders. • In CHD, PaO2 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.

42. CHD • Increased pulmonary vascularity: • Total anomalous pulmonary venous return • Truncus arteriosus • Transposition of the great arteries • Other complex lesions without pulmonic stenosis • Decreased pulmonary vascularity: • Tetralogy of Fallot • Ebstein’s anomaly • Hypoplastic right heart, tricuspid atresia • Complex lesions with pulmonic stenosis

43. Prostaglandin E1 • Keeps the ductus open • 0.05 to 0.1 mcg/kg/min with an increase to 0.2 mcg/kg/min over several minutes • Side effects: Apnea, pulmonary congestion, fever, hypotension, seizures, and diarrhea • Consider elective intubation.

44. Noncyanotic CHD • May present with CHF or heart murmurs heard during physical exam • Left-to-right shunts • Excess pulmonary vascularity • ASD, VSD, PDA • Obstructive lesions • Aortic stenosis, coarctation of the aorta, mitral stenosis, pulmonic stenosis

45. Clinical Features • CHF: Tachypnea, tachycardia, diaphoresis, decreased feeding, hepatomegaly, murmurs, gallop rhythms, pulmonary edema • Decreased activity or poor sleeping with respiratory distress

46. Diagnostic Studies • CXR: Cardiomegaly, pulmonary vascular congestion • ECG: Abnormal axis, ST segment changes • Echocardiogram: Definitive anatomic diagnosis, degree of congestive heart failure (chamber sizes, contractility)

47. Management of CHF • Give oxygen, assisted ventilation if needed. • Elevate head and shoulders 45 degrees. • Monitors, pulse oximetry • Obtain IV access. • Send laboratories. • CXR and ECG • Furosemide, nitroglycerin, digoxin • Inotropes (dobutamine) for signs of shock

48. Case Study 2:“Chest Pain, SOB” • 10-year-old boy presents with chief complaint of chest pain and shortness of breath. • 5 days of cold and cough symptoms • He has been lying around a lot and has missed 1 week of school. • Usually a very active child but complains that he is “just too tired” to play

49. Initial Assessment PAT: • Abnormal appearance, abnormal breathing, abnormal circulation Vital signs: • HR 130, RR 44, BP 90/65, T 37.8°C, O2 sat 90% on room air, increases to 100% on O2

50. Initial Assessment A: Patent B: Intermittently shallow and deep; rapid respiratory rate C: Pale; pulse rapid, thready, and weak D: No focal deficits, GCS 15 E: No signs of injury