Approach to cyanotic chd

Brief overview of cyanotic congenital heart disease. Largely adapted from openpediatrics.org

1. Approach to Cyanotic Heart Disease Rob Parker Pediatric Critical Care Fellow

2. Outline Definition Physiology Diagnostic Considerations Types of Cyanotic heart disease ICU-based therapy

3. Cyanotic Newborn Cyanosis is blueish discoloration of the skin due to 5g/ml or more of deoxygenated hemoglobin in the capillary bed Arterial Hypoxemia = arterial saturation <95% Potential Causes Low arterial oxygen saturation Low cardiac output Venostasis

4. Physiologic Causes of Cyanosis

5. Physiologic Causes of Cyanosis Pulmonary Venous oxygen saturation Pulmonary venous blood is not fully saturated Seen in lung disease (“pulmonary cyanosis”) Pulmonary Edema Atelectasis

6. Physiologic Causes of Cyanosis Pulmonary Venous oxygen saturation Ratio of pulmonary to systemic blood flow ( Qp:Qs ) Qp:Qs = (SaO2-SmvO2)/(SpvO2-SaO2)

7. Physiologic Causes of Cyanosis Pulmonary Venous oxygen saturation Ratio of pulmonary to systemic blood flow ( Qp:Qs ) Shunting If the resistance in the body is higher, blood will shunt from L  R If the pulmonary resistance is high, blood will shunt from R  L

8. Qp:Qs : (SaO2-SmvO2)/(SpvO2-SaO2) (50-25)/(100-50)=0.5 (75-50)/(100-75)=1.0 (86-61)/(100-86)=2.0 (94-77)/(100-94)=3.0

9. Physiologic Causes of Cyanosis R  L shunt Ex. ToF Think, non-compliant RV Narrow RVOT Leads to RL shunting at VSD

10. Physiologic Causes of Cyanosis R  L shunt Ex. ToF R  L shunt Ex. Severe pulmonic stenosis Think, non-compliant RV Narrow RVOT Leads to RL shunting at PFO

11. Physiologic Causes of Cyanosis R  L shunt Ex. ToF Ex. Severe pulmonic stenosis Complete Mixing Ex. Single ventricle lesions (tricuspid atresia) Unrelated to vascular resistance

12. Physiologic Causes of Cyanosis R  L shunt Ex. ToF Ex. Severe pulmonic stenosis Complete Mixing Ex. Single ventricle lesions (tricuspid atresia) Unrelated to vascular resistance Ex. Truncus Arteriosis

13. Physiologic Causes of Cyanosis R  L shunt Ex. ToF L  R shunt Ex. Severe pulmonic stenosis Complete Mixing Ex. Single ventricle lesions (tricuspid atresia) Transposition physiology Ex. D-TGA

14. Determinants of Arterial O2 Saturation with CHD Pulmonary Venous oxygen saturation Pulmonary venous blood is not fully saturated Ratio of pulmonary to systemic blood flow ( Qp:Qs ) R  L shunting Complete mixing lesions Transposition physiology

15. Determinants of Arterial O2 Saturation with CHD Pulmonary Venous oxygen saturation Pulmonary venous blood is not fully saturated Ratio of pulmonary to systemic blood flow ( Qp:Qs ) R  L shunting Complete mixing lesions Transposition physiology Systemic blood flow Hgb Content of the blood Oxygen content: 1.34* Hb *SaO2 + 0.003*PaO2 Total body oxygen consumption (VO2) Systemic blood dilutes O2 level of pulmonary blood

16. Oxygen Delivery Oxygen Content of the Lungs Arterial oxygen saturation Hemoglobin Blood flow into the capillary bed Analogous to cardiac output or systemic blood flow The greater the amount of systemic blood flow and the higher O2 content, the higher the MVO2 saturation

17. Determinants of MVO2 Saturation with CHD Drop in mixed venous O2 saturation due to: ↓ systemic blood flow ↓ Arterial Saturation or ↓ Hgb  ↓ oxygen delivery to body (DO2) ↑ VO2 = ↑ oxygen extraction/consumption

18. Determinants of Arterial O2 Saturation with CHD Exception to the Rule D-TGA Key is how much mixing of “red” and “blue” blood streams

19. Diagnostics

20. Diagnostic Considerations Clinical Characteristics/Differences from: Lung disease of newborn Persistent Pulmonary Hypertension of Newborn Definitive diagnosis is made by ECHO

21. Red Flags for CHD Cyanosis with “happy” tachypnea Tachypnea without dyspnea Breathing fast but easily Lung Disease Patients ↓ Non-compliant lungs ↓ Tachypnea and Dyspnea CHD Patients ↓ Very compliant lungs ↓ Tachypnea without Dyspnea (Tachypnea from hypoxic respiratory drive)

22. Red Flags for CHD Cyanosis with “happy” tachypnea Exception is Tachypnea and Dyspnea Total Anomalous Pulmonary Venous Connection (TAPVC)

23. Red Flag for CHD Cyanosis with happy baby Differential Cyanosis R  L Shunting of venous blood into descending aorta Ex. PPHN Shunting at PFO and PDA due to PVR being very high Oxygen sat in R arm much higher than legs

24. Red Flag for CHD Cyanosis with happy baby Differential Cyanosis R  L Shunting of venous blood into descending aorta Ex. PPHN Shunting at PFO and PDA due to PVR being very high Oxygen sat in R arm much higher than legs Ex. Interrupted aortic arch

25. Red Flag for CHD Cyanosis with happy baby Differential Cyanosis R  L Shunting of venous blood into descending aorta Reverse differential cyanosis Ex. D-TGA Can occur with high PVR or CoA

26. Red Flag for CHD Cyanosis with happy baby Differential cyanosis Murmurs Grade III/VI or louder Continuous mumurs in back ToF or PA “To and fro ” LUSB murmur Absent pulmonary valve

27. Red Flags for CHD Cyanosis with happy baby Differential cyanosis Murmurs Hyperoxia Test Administer 100% O2 Typical response: PaO2 increases  lung disease No/Minimal response: PaO2 does not increase as expected  CHD Infradiaphragmatic TAPVR can have high PaO2  cant get back to the heart PaO2 <200mmHg on 100% FiO2 is consistent with CHD

28. Red Flags for CHD Cyanosis with happy baby Differential cyanosis Murmurs Hyperoxia Test PaO2 out of Proportion to CXR Low PaO2 with normal appearing CXR Remember: TAPVC looks like Pulmonary Edema on CXR (Snowman in a snowstorm)

29. Red Flags for CHD Cyanosis with happy baby Differential cyanosis Murmurs Hyperoxia Test PaO2 out of Proportion to CXR Electrocardiogram Unusually normal at birth Left axis deviation  Tricuspid atresia

30. Red Flags for CHD Cyanosis with happy baby Differential cyanosis Murmurs Hyperoxia Test PaO2 out of Proportion to CXR Electrocardiogram CXR Dextrocardia Right Aortic Arch ToF , TA, d-TGA, VSD, PS, ToF or ToF with PA  upturned cardiac apex and flat pulmonary segment

31. Diagnosis of CHD Diagnosis D-TGA IVS TAPVC Ebsteins TA PA IVS PS ToF + PS ToF + PA Atrial Level Ventricular Level

32. Diagnosis CXR D-TGA IVS TAPVC Ebsteins TA PA IVS PS ToF + PS ToF + PA Diagnosis of CHD Diagnosis CXR/PBF D-TGA IVS TAPVC ↑ Ebsteins TA PA IVS PS ToF + PS ToF + PA Diagnosis CXR/PBF D-TGA IVS TAPVC ↑ Ebsteins ↓ TA ↓ PA IVS ↓ PS ↓ ToF + PS ↓ ToF + PA ↓ Diagnosis CXR/PBF D-TGA IVS ↑ /Normal TAPVC ↑ Ebsteins ↓ TA ↓ PA IVS ↓ PS ↓ ToF + PS ↓ ToF + PA ↓

33. Diagnosis of CHD Diagnosis Key Findings CXR D-TGA IVS ↑/ Normal TAPVC ↑ Ebsteins Large heart ↓ TA ↓ PA IVS ↓ PS ↓ ToF + PS ↓ ToF + PA ↓ Diagnosis Key Findings CXR D-TGA IVS ↑/ Normal TAPVC Pulmonary Edema ↑ Ebsteins Large heart ↓ TA ↓ PA IVS ↓ PS ↓ ToF + PS ↓ ToF + PA ↓

34. Diagnosis of CHD Diagnosis Hypertrophy Key Findings CXR D-TGA IVS ↑/ Normal TAPVC Pulmonary Edema ↑ Ebsteins Large heart ↓ TA LVH ↓ PA IVS LVH ↓ PS LVH ↓ ToF + PS RVH ↓ ToF + PA RVH ↓

35. Diagnosis of CHD Diagnosis QRS Axis Hypertrophy Key Findings CXR D-TGA IVS ↑/ Normal TAPVC Pulmonary Edema ↑ Ebsteins Large heart ↓ TA -30 ° to +90° LVH ↓ PA IVS +30 ° to +90° LVH ↓ PS +30 ° to +90° LVH ↓ ToF + PS RVH ↓ ToF + PA RVH ↓

36. Diagnosis of CHD Diagnosis Physical Exam QRS Axis Hypertrophy Key Findings CXR D-TGA IVS ↑/ Normal TAPVC Pulmonary Edema ↑ Ebsteins Large heart ↓ TA -30 ° to +90° LVH ↓ PA IVS No Murmur +30 ° to +90° LVH ↓ PS Systolic Ejection Murmur +30 ° to +90° LVH ↓ ToF + PS Systolic Ejection Murmur RVH ↓ ToF + PA No Murmur RVH ↓

37. Just Get an ECHO

38. Ductus Classification Examples of CHD

39. Ductus Centric Classification of CHD Severe Obstruction to Pulmonary Blood Flow Ductus Dependent PGE-1 Helpful! Little Obstruction to Pulmonary Blood Flow Ductus Independent PGE-1 NOT helpful! Case-Specific Ductus Dependence Ex. D-TGA Ductus Deleterious Ex. TAPVC w/ obstruction

40. Ductus Centric Classification of CHD Severe Obstruction to Pulmonary Blood Flow Ductus Dependent PGE-1 Helpful! Critical Pulmonic Stenosis/Pulmonary Atresia

41. Ductus Centric Classification of CHD Severe Obstruction to Pulmonary Blood Flow Ductus Dependent PGE-1 Helpful! Critical Pulmonic Stenosis/Pulmonary Atresia ToF with severe RVOT Obstruction Life threatening hypoxemia due to reduction in pulmonary blood flow

42. Ductus Centric Classification of CHD Severe Obstruction to Pulmonary Blood Flow Ductus Dependent PGE-1 Helpful! Critical Pulmonic Stenosis/Pulmonary Atresia ToF with severe RVOT Obstruction Single Ventricle with severe PS or PA If there is no VSD or the area under the MPA is very narrow, pulmonary blood flow is ductal dependent

43. Ductus Centric Classification of CHD Severe Obstruction to Pulmonary Blood Flow Ductus Dependent PGE-1 Helpful! Critical Pulmonic Stenosis/Pulmonary Atresia ToF with severe RVOT Obstruction Single Ventricle with severe PS or PA HLHS

44. Ductus Centric Classification of CHD Severe Obstruction to Pulmonary Blood Flow Ductus Dependent PGE-1 Helpful! Critical Pulmonic Stenosis/Pulmonary Atresia ToF with severe RVOT Obstruction Single Ventricle with severe PS or PA HLHS Ebstein’s Malformation Can be mild to severe with massively dilated RV that cannot sufficiently pump blood to the lungs Severe Ebsteins requires an open ductus

45. Ductus Centric Classification of CHD Little Obstruction to Pulmonary Blood Flow Ductus Independent PGE-1 NOT helpful! ToF (most) ToF w/ MAPCAs No connection to pulmonary arteries Blood enters lungs through aortopulmonary collaterals or through PDA

46. Ductus Centric Classification of CHD Little Obstruction to Pulmonary Blood Flow Ductus Independent PGE-1 NOT helpful! ToF (most) Truncus Arteriosus

47. Ductus Centric Classification of CHD Little Obstruction to Pulmonary Blood Flow Ductus Independent PGE-1 NOT helpful! ToF (most) Truncus Arteriosus Single Ventricle with no outflow tract obstruction Double Outlet LV

48. Ductus Centric Classification of CHD Little Obstruction to Pulmonary Blood Flow Case Specific D-TGA Mixing at atrial level is primary determinant of saturation Open PDA can lead to improved pulmonary blood flow if needed Can make some acutely ill due to shunting from body

49. Ductus Centric Classification of CHD Little Obstruction to Pulmonary Blood Flow Ductus Deleterious TAPVC Obstruction to blood returning to heart leads to high resistance to blood flow to lungs With an open ductus, blood tends to go away from lungs to aorta Therefore we avoid use of PGE1

50. ICU Therapy

51. ICU Therapy Goals Assess and provide adequate DO2 Need to start before a definitive diagnosis Measure arterial O2 saturation (SpO2 is not adequate) Make an accurate Diagnosis More definitive with ECHO but still can be a guess at times Definitive management often with surgery

52. Tissue Oxygenation How to determine Inadequate Oxygenation: Serum lactate, UOP, NIRS, MVO2 Newborns with adequate systemic blood flow, Hb and VO 2 PaO2 > 20mmHg transiently can often be tolerated but ideal goal is a PaO2 >30 and no acidosis  

53. ICU Therapy: Hypoxia Management Optimize hematocrit Often want Hct >40% or 45% for single ventricle kids Older patients that are chronically hypoxic tend to be polycythemic Ensure adequate systemic perfusion May need volume or vasopressors Optimize ventilation Ensure adequate pH and PVR control Minimize VO2 May need pharmaceutical paralysis, mechanical ventilation, sedation, temperature control Reduce or eliminate acidosis, ensure euglycemic and adequate calcium levels

54. Prostaglandins – PGE1 Uses Risks and Side Effects Clinical Pearls Obstructed Pulm Blood Flow d-TGA? Dose: To open a closed ductus: 0.05-0.1 ug /kg/min To keep open a ductus: 0.01-0.02 ug /kg/min Harmful in obstructed TAPVC Can cause or worsen systemic hypotension Can cause Apnea Additive effect in sedated babies or prematurity Systemic vasodilator May need volume or inotropes Consider intubation for transportation if on PGE1 Use sedatives sparingly Consider caffeine

55. Balloon Atrial Septostomy Uses Risks and Side Effects Clinical Pearls d-TGA Low risk of complications Air embolism Systemic/pulmonary vein injury AV valve injury May still require an open ductus

56. Balloon Atrial Septostomy

57. Unusual Situations ↑ PVR d-TGA May need iNO , vasodilators or even ECMO Alveolar capillary dysplasia with misalignment of pulmonary veins Can be seen in left sided obstructed lesions

58. Unusual Situations ↑ PVR d-TGA Alveolar capillary dysplasia with misalignment of pulmonary veins Absent ductus with RV outflow obstruction Can be seen in ToF PGE1 will not help May need to increase SVR (phenylephrine) ECMO can be useful May need to sent open RV outflow tract

59. Unusual Situations ↑ PVR d-TGA Alveolar capillary dysplasia with misalignment of pulmonary veins Absent ductus with RV outflow obstruction Obstructed TAPVC Require emergency surgery

60. Single Ventricle Physiology with Unobstructed PBF ↑ PBF Decrease in PVR tends to send more blood to the lungs Mild hypoxemia ( sats >80%) Ex. Truncus Arteriosus HLHS

61. ICU Therapy for Single Ventricle Avoid therapy that ↓ PVR Avoid hyperoxia and alkalosis Avoid systemic hypertension Inotropic support and diuretics Sub-ambient O2 if signs of ↓ systemic perfusion Mounting acidosis, worsening creatinine and poor UOP

62. Summary Prompt diagnosis of cyanotic heart disease Treatment based on diagnosis PGE1 may be very helpful Do not wait for definitive diagnosis to start PGE1 In absence of diagnosis: Optimize hematocrit Minimize O2 consumption (VO2) Promote systemic blood flow