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A 2-month-old patient with a nonrestrictive ventricular septum defect (VSD), pulmonary edema, and congestive heart failure (CHF) presents for VSD closure.
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PREOPERATIVE CONSIDERATIONS
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There are several kinds of VSDs:
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Perimembranous = paramembranous = membranous = infracristal VSD, most common.
Subarterial VSD.
Inlet defects = atrioventricular canal-type VSD.
Muscular VSDs, often multiple, are in the trabecular portion of the ventricular septum.
Ventral septal defects can be isolated lesions or part of complex malformations.
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Smaller VSDs are restrictive with a pressure gradient across the defect; the shunt is determined by the pressure difference. Larger VSDs are nonrestrictive; the shunt is determined by the relative resistance of the systemic and pulmonary vasculature. Since the pulmonary vascular resistance (PVR) is usually lower than the systemic vascular resistance, pulmonary flow is greater than systemic blood flow and the shunt is left to right.
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Infants with nonrestrictive VSDs will increase their shunt as the PVR drops in the first two weeks of life, resulting in pulmonary overcirculation and CHF. Patients frequently have respiratory tract infections and are on diuretics, digitalis, and antibiotics. The overcirculation will then lead to a fixed PVR and end decades later in suprasystemic pulmonary pressures and a shunt reversal (Eisenmenger syndrome) unless the VSD is closed.
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Infants with a restrictive VSD may be asymptomatic. Spontaneous closure of VSDs, particularly perimembranous VSDs, can occur.
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ANESTHETIC MANAGEMENT
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If the patient has CHF, a primary narcotic technique may be chosen.
Decrease pulmonary blood flow by avoiding hyperventilation and decreasing fraction of inspired oxygen (FiO2) for patients with nonrestrictive VSDs.
In patients with pulmonary hypertension, avoid hypercarbia and acidosis.
Cardiopulmonary bypass with bicaval and aortic cannulation.
Two IVs, aline, with or without a central line.
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POSTOPERATIVE CONSIDERATIONS
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Pulmonary hypertension can be seen after the repair of large, isolated ventricular septum defects.
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DOs and DON’Ts
✓ Do treat junctional ectopic and supraventricular tachycardia aggressively.
✓ Do treat postoperative pulmonary hypertension with intravenous vasodilators or inhaled nitric oxide.
⊗ Do not needlessly increase the FiO2 in patients with nonrestrictive VSDs; you may increase the shunt by lowering the PVR.
⊗ Do not overventilate patients with nonrestrictive VSDs; hypocarbia will lower the PVR and increase the shunt.
✓ Do diurese infants prior to extubation and for 1-3 days after the procedure.
✓ Do consider extubation of older and uncomplicated patients.
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Percutaneous closure of a VSD is not as straightforward as ASD closure; it is most commonly done for muscular VSDs.
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Large defects or defects that caused CHF are repaired in infancy; moderate-size VSDs are usually followed up until 5 years of age. Small VSDs are medically managed, but ...