Operability in a 5-Month-Old With a Large VSD and Borderline Pulmonary Vascular Resistance
5-month-old boy, 4.8 kg, with a large perimembranous VSD. Catheterization: pulmonary artery pressure 68/32 (mean 45) mmHg, aortic pressure 78/42 (mean 55) mmHg, Qp/Qs 1.9, PVR 5.2 Wood units·m2. With 100% oxygen and inhaled nitric oxide, PVR falls to 3.4 Wood units·m2 and there is no fixed component. He has had two pneumonias, weight is at the 3rd percentile, and he is tachypneic with feeds. The family wants repair.
1. Interpret the hemodynamics. Is he operable, and what is the main postoperative risk?
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The pressures show pulmonary hypertension that is still reactive: PVR 5.2 falls to 3.4 with oxygen and iNO, and Qp/Qs is 1.9. At 5 months, a PVR of 5.2 is elevated but not fixed; the fall is meaningful. He is operable, but he is a high-risk repair because of malnutrition, recurrent pneumonia, and reactive pulmonary vasculature. The main postoperative risk is pulmonary hypertensive crisis, especially in the first 24–72 hours, with right ventricular failure, low cardiac output, and hypoxia. I would repair after optimizing nutrition and treating infection, with iNO and pulmonary vasodilators available. If PVR had been above 8–10 Wood units/m2 and nonreactive, repair would be contraindicated or require a fenestrated strategy.
2. Outline a perioperative strategy to prevent and treat pulmonary hypertensive crises.
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Perioperative strategy:
- Preop: treat pneumonia, optimize nutrition, avoid dehydration; have iNO and inhaled or IV pulmonary vasodilators ready.
- Intraop: avoid hypoxia, hypercarbia, acidosis, hypothermia, and light anesthesia; use a ventilator strategy that maintains functional residual capacity without high airway pressures.
- Postop: deep sedation and analgesia early, muscle relaxation if needed, maintain normal pH and PaCO2, avoid suctioning storms, and use iNO for crisis. Milrinone can help RV function but may worsen vasodilation; norepinephrine supports SVR.
- Monitor with central venous saturation, lactate, echo, and frequent blood gases. Have ECMO available if RV failure is refractory.
- After VSD closure, pulmonary blood flow falls, so the crisis risk should improve, but the reactive bed can still constrict.
3. If the family asked to wait until he is older and bigger, how would you counsel them?
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Waiting is not benign. A large VSD with PVR 5.2 and recurrent pneumonia places him at risk for irreversible pulmonary vascular disease, failure to thrive, and sudden pulmonary hypertensive crisis. The window for a low-risk repair is now, not after another year. I would explain that bigger is not necessarily safer if the pulmonary vascular bed remodels. Offer a concrete plan: treat infection, nutrition optimization for 1–2 weeks, then repair. If the family still declines, document informed refusal and arrange close follow-up with echo and saturation checks; return precautions for worsening tachypnea, feeding failure, or cyanosis.