Single (Including Common) Ventricle

HLHS is the most common SV congenital cardiac malformation.

HLHS accounts for 7.5% of newborns with CHD.

Male predominance for HLHS.

Paradoxical emboli.

Complications of chronic hypoxemia: Hyperviscosity, decreased coagulation factors and platelets

Surgical shunts (narrowing of vessels anastomosed, obstructed shunts)

Hypovolemia-induced poor pulm blood flow or shunt occlusion.

Additional risks specific to anatomy and planned procedure.

Effect of changes in PVR, SVR, and cardiac function on blood flow, cardiac output, and O ₂ saturation.

Diastolic pressure and coronary perfusion.

AV valve regurgitation.

Systolic and diastolic dysfunction.

Associated anomalies.

Increasingly common to care for CHD and SV pts having noncardiac surgery who may be at various stages in the palliation repair process and may have comorbidities including protein losing enteropathies, plastic bronchitis, ventricular dysfunction, and arrhythmias.

A wide variety of lesions are usually associated with atresia of the ipsilateral AV or semilunar valve resulting in SV physiology:

• TA is the prototypic single left ventricle (see Tricuspid Atresia).

• HLHS with mitral and aortic stenosis/atresia is the prototypic single right ventricle.

Other anatomies include unbalanced AV canal, some double inlet or double outlet ventricles, and some heterotaxies.

Initial lesion requires mixing of systemic and pulm venous return at ASD or VSD level. The SV output is divided between pulm and systemic circulations.

SV anatomy may be associated with hypoplasia of a great vessel (pulm artery or aorta) and prior to initial palliation; systemic or pulm blood flow may be dependent on ductus arteriosus patency.

Balance of blood flow in each Qp:Qs is governed by the relative resistance to flow as determined by both anatomic and vascular resistance considerations.

Goal throughout all stages is to balance the Qp:Qs at 1:1.

• With complete mixing, Qp:Qs at 1:1 results in sat of 75–80% at FiO ₂ 0.21.

FiO ₂ , CO ₂ , and pH management can be used to manipulate the Qp:Qs.

Qp:Qs > > 1 results in pulm overcirculation/pulm vascular congestion and potentially hypoperfusion to end organs.

Qp:Qs < < 1 results in hypoxemia.