Part 3: Pediatric anesthesia: Overview

Question 1

Describe patent ductus arteriosis?

Answer 1

• Abnormal connection from the high pressure aorta to the low pressure pulmonary artery allows an increased volume load to the lungs and left heart.
• Arrow shows blood flow

Question 2

Describe atrial septal defect?

Answer 2

• Large volume load to right atrium from blood flow from left atrium
• Left to right shunt
• Right to left shunt occurs at atrial level
• Cases require CPB and anesthesia complexity is proportional to surgical complexity
• Air must be carefully avoided in all patients but especially in ostium primum patients

Question 3

Describe Ventricular Septal Defect?

Answer 3

• The most common congenital heart defect
• Left to right shunt
• Eisenmenger’s Complex – situation where pulmonary vascular disease results in pulmonary hypertension sufficient to reverse the shunt to right to left and cyanosis develops
• Air is of concern in all patients but especially as the flow equalizes or reverses

Question 4

Describe coarctation of the Aorta?

Answer 4

• This can occur before the ductus (preductal) at the ductus or after the ductus (post ductal). Each has different implications and hemodynamics
• Left ventricle supplies the upper body
• Right ventricle, through the ductus primarily supplies the lower body
• Significant difference in upper and lower body blood pressure
• 50% have bicuspid aortic valve
• May present early with CHF
• Preductal are often associated with other congenital problems and are more difficult to repair
• Postductal are commonly seen in older children

Question 5

Describe tetrology of fallot?

Answer 5

• Right to left shunt
• Decreased flow to lungs
• Increased flow to body
• Clubbing of extremities, iron deficiency anemia, polycythemia, transient cerebral ischemia
• Inhalation induction slow; less PA flow
• IV induction faster; R->L shunt to brain
• Hypoxia, hypotension, decreased CO, vasodilation (increased R->L shunt all put patient at risk)
• Squatting common, probably increases systemic resistance and lessens R->L shunt and increases pulmonary flow and oxygenation

Question 6

Describe endocardial cushion defect?

Answer 6

• Failure to develop results in mitral/tricuspid problems
• Flow can be in any direction between the four chambers
• Most common problem with Down’s syndrome
• Repair is long involving patches to form four chambers and reconstruct at least the mitral valve
• Often have problems with conduction system postop
• Almost always have pulmonary hypertension

Question 7

Describe Truncus arteriosis.

Answer 7

• Truncus divides into pulmonary artery and aorta
• Failure to form properly leaves a common trunk with venous and arterial blood
• Pulmonary blood flow varies with type – from increased to diminished
• In the fourth type, with no pulmonary artery, flow to lungs is via bronchial circulation
• Always cyanotic
• Often are in CHF at time of surgery

Question 8

Describe transposition of the great vessels?

Answer 8

• Ao attaches to the RV and PA attaches to the LV
• To be compatable with life other lesions must exist; PDA, VSD, or VSD
• Intact ventricular septum – Foramen ovale and ductus arteriosus allow mixing
• Degree of mixing determines “pink or blue” baby. Minimal murmur
• VSD – with decrease in pulmonary resistence R>L shunt occurs mixing via FO allows oxygenation. Holosystolic murmur and increased pul volume
• VSD with subpulmonic stenosis – here less pulmonary flow from the stenosis causes L>R shunt at VSD and R>L shunt at FO. As pulmonary flow decreases shunts increase and cyanosis worsens

Question 9

Describe Ebstein’s anomaly?

Answer 9

• Part of the ventricle is above the tricuspid valve

* R>L shunt

Question 10

Describe aortic stenosis & Left outflow obstructions?

Answer 10

• Three leaflet valve usually no regurg

* Two leaflet valve usually has regurg

Question 11

Describe pulmonary stenosis & right outflow obstruction?

Answer 11

Often associated with rubella syndrome

Question 12

Describe tricuspid atresia?

Answer 12

Blood flow is across atrial septum (FO/ASD)