based extensively off the notes of lecture by Shaine Morris, MD 6/2013
Categories of an infant with CHD
-PGE likely will help:
-Shock - not enough Qs
-Happy Cyanosis - not enough Qp
-PGE likely won't help:
-Sick Cyanosis - = pulmonary congestion, pulmonary blood flow cannot get out
-Happy Tachypnea - pulmonary overcirculation
Shock - Not enough systemic flow
-bc of obstruction to Qs; the PDA no longer compensates for the problem (bc it is closing)
-Critical Aortic Stenosis
-Ao Arch hypoplasia/Coarctation
-Interrupted Aortic Arch
-Hypoplastic Left Heart Syndrome
-Sx
-tachycardic
-lethargic
-grey/pale/mottled
-no murmur usually (sometimes + w AS)
-cool limbs
-Low BP
-All are ductal dependent for Qs = need the PDA to supply Q to lower body. In some, need PDA to supply the coronaries & head/neck vessels via retrograde Q thru the arch (e.g. AS, HLHS)
--> lower extrem SaO2 will be low (bc get's Q fr the PA via the PDA), and if AS & HLHS, the upper extrem will have low SaO2 too (bc the blockage is prior to the head/arm vessels so they get retrograde Q via the PDA)
-Often have Differential Cyanosis = upper extremities have higher SaO2 than lower
-CXR - varied, usually Nl w AS & CoAo; IAA often assoc w VSD so --> overcirc; HLHS--> overcirc
Happy Cyanosis - not enough pulmonary flow
-bc of obstruction to Qp
-Ductal dependent
-if PDA open--> mild/mod cyanosis, much worse as it closes
-Severe PS (Critical PS)
-Pulm Atresia w Intact Ventricular Septum
-Pulm Atresia/VSD (aka severe TOF)
-Tetralogy of Fallot
-Tricuspid Atresia (if w restrictive VSDor signif PS)
-Sx
-cyanosis
-mild tachypnea, d/o degree of hypoxia
-+/- murmur (PS yes, pulm atresia no)
-CXR- Nl to dark lung fields
Sick Cyanosis - pulmonary venous congestion
-bc of pulm vn return obstruction--> can't exit--> signif resp distress, cyanosis, low CO
-*** Likely one of these with really sick newborn at <24 hrs of life
-Obstructed TAPVR
-TGA with intact/restrictive atrial septum
-HLHS with intact/restrictive atrial septum
-Sx
-Hypoxia
-resp distress- tachypnea/retractions
-+/- poor output w cool extrem/pallor
-Get sick quickly
-CXR- pulm edema
Happy Tachypnea - too much pulmonary flow
-bc of pulmonary overcirculation (Qp:Qs usually >2:1), but cardiac output is maintained
-includes L to R shunts...
-Moderate/Large VSD
-Large PDA
-AV Canal Defect
-Truncus Arteriosus
-Aortopulmonary Window
-Unobstructed TAPVR
-Sx
-tachypnea
-retractions- but usually comfortable
-cardiomegaly, hepatomegaly
-poor PO, poor wt gain
-if cyanotic- the pt must also have a mixing lesion:
-Truncus Arteriosus
-DORV with no PS
-TGA with VSD without a restrictive atrial septum
-Single ventricle with no outflow tract obstruction
-CXR: increased pulmonary vascularity
What to check before the echo?
-CXR
-4 extrem BP - r/o CoAo
-Pre & Post SaO2 (both upper and at least 1 lower)
-ECG (?sensitivity for a specific lesion)
-CXR:
-Shock- Nl/increased pulm vasc, cardiomegaly
-if Left sided obstructive lesion- may cause incr Qp if single ventricle or if VSD
-Happy cyanotic- Nl/decr pulm vasc; Nl cardiac size
-often Nl when PDA open, then decr when it closes (looks like a TOF CXR)
-Sick Cyanotic- pulm edema, cardiomegaly
-Happy Tachypnea- incr pulm vasc, +cardiomegaly
-4 Extremity BP
-DDx CoAo from other L sided obstructive lesions
-SBP in R arm should be at least 10mmHg higher than SBP in legs if +CoAo
-Check both upper extrem bc pt might have an aberrant R subclavian that comes fr descending Ao, after the PDA insertion (site of coarctation), so will be low/Nl and similar to that of leg, giving a false negative for coarctation
-in HLHS & AS they are NOT abnormal
-if IAA, can be misleading if the PDA is open bc it still gets good Q...
-Pre & Post Ductal O2 Sats
-No diff:
-R sided lesions (PS/Pulm Atresia)
-TAPVR
-Truncus
-Isolated intracardiac shunts (VSD) and AP Windows
-HLHS w Aortic Atresia (no oxygenated blood going forward to create a difference)
-Pre>Post = PDA is open w a mainly R to L shunt to the lower body, w arch supplied by the Ao
-Pulm htn (>/= systemic P)
-L heart obstructive lesions - critical AS, Interrupted Ao Arch, Coarctation of the Aorta
-Post>Pre = Reverse Differential Cyanosis = TGA + PDA + one of the following:
-TGA + Coarctation of the Aorta or IAA
-TGA + Pulmonary Hypertension
-Hyperoxia Test
= apply 100% FiO2 and check PaO2: Fail = PaO2 is <100-250mmHg on 100%FiO2 for 10 minutes; can only be done by oxyhood or ET tube.
-helps DDx bn an O2 responsive (noncardiac) etiology of hypoxia, vs a cyanotic CHD
-Not as useful if the echo machine is available
-Everyone discussed above will fail the test, except for happy cyanotics with no mixing lesions, critical left sided lesions if the duct is closed (but then they'd be dead)
Mgt
-Shock - L sided obstruction lesions
-PGE - bc all are ductal dependent
-Improve the acidosis - sedate, ETT, pressors...
-When stable--> correct/palliate
-AS: Balloon valvuloplasty
-CoAo/IAA: repair the arch
-HLHS: Norwood/BTS
-Happy Cyanotic - too little Qp
-PGE - bc often ductal dependent
-O2
-Supply a Qp source:
-BT shunt, PDA stent, Pulmonary Balloon valvuloplasty, complete repair (TOF)
-Sick Cyanotics - pulmonary congestion
-STAT cath lab for intact/restrictive atrial septum (HLHS, TGA, AS, etc)
-STAT operation - obstructive TAPVR
-PGE if HLHS or TGA
-check the atrial septum early:
-intact/restrictive?
-R to L shunting? (TAPVR)
-Happy Tachypnics - pulmonary overcirculation
-less emergent
-usually don't need PGE (already have much Qp, no problem w Qs)
-diuretics, possible afterload reduction to promote Qs rather than Qp
-Will need surgical repair (often at 3-6mo or late, varies by Sx/lesion)
-if CHF Sx despite Rx, c/s a PA band
-except for truncus & AP windows- overcirculation in these pts can be severe, and result in NEC, so repair as a a newborn