Pediatric Anesthesiology
Congenital Heart Disease - 5
VII. Preanesthetic evaluation of CHD
A. History
- cyanosis
- exercise tolerance
- feeding behavior in infants
- medications
- digoxin: may hold AM dose
- diuretics: may hold AM dose
- propranolol: continue in TOF
- calcium channel blockers
- previous cardiac/other surgery
B. Physical exam
- breathing
- pulses (Blalock-Taussig shunt, coarct, aortic insufficiency, hypovolemia, tamponade)
- cyanosis (tongue)
- height and weight, percentile
- hepatosplenomegaly (children develop biventricular failure)
- surgical scars
- neurologic status
- newborn:
- most severe lesions have little or no murmur
- benign lesions often have definite murmur
- TOF
- loud, long murmur suggests good pulmonary blood flow
- diminishing murmur suggests less pulmonary blood flow
C. Lab
- Hematocrit (Hct) is best indicator of magnitude of average, chronic R->L shunt.
- ECHO: excellent screening tool: may obviate cardiac catheterization
- Cardiac catheterization
- Box diagram helpful
- RVOT, pulmonary obstruction
- PVR/SVR and response to O2
- Ao obstruction
- Restrictive vs nonrestrictive shunt lesions
- Systemic O2 saturation
- CxR
- Cardiomegaly or great vessel enlargement may impair ventilation.
- Large LA or LV may lead to left lower lobe atalectasis.
- ECG
- Electrocardiographic hypertrophy is not usually a good indicator of severity.
- SVT: ASD, mitral valve prolapse
- PVC's: postop TOF
- RBBB: postop usually of no consequence, unless with left anterior hemiblock
- Left anterior hemiblock (abnormal superior vector) congenitally present with endocardial cushion defect (ECD).
- Ischemia: usually not seen unless anomalous left coronary or aortic runoff (AI, PDA, truncus).
D. Premedication
- In general, continue all preop needed medicatons, especially PGE1, propranolol.
- Young infants, class III+ patients: no premeds except possibly an anticholinergic.
- Prone to TOF spells: morphine 0.1-0.2 mg/kg IM, IV.
- Class II: moderately heavy premed OK.
- Consider ketamine 1-2 mg/kg IM under supervision of anesthesiologist in preop area.
