Case Report
An eight month old infant was brought to our emergency services with features of failure. A systolic murmur was heard over left sternal border. Chest X-ray revealed cardiomegaly and pulmonary plethora. In view of respiratory distress, she was provided invasive ventilator support. Electrocardiogram (ECG) revealed sinus rhythm, right axis of QRS vector and mild ST depression of inferior leads (figure 1). On trans-thoracic echocardiography (TTE), single ventricle (SV) physiology in the form of double inlet left ventricle (DILV), large bulboventricular foramen and levo transposition of great vessels (l-TGA) was found. Aorta was arising from rudimentary chamber. Recurrent episodes of left lung collapse while on mechanical ventilation, delayed weaning of the child. Decongestive measures were maximized and patient was weaned off from the ventilator after 12 days. However, the infant remained in respiratory distress even with supplemental oxygen. In view of intractable failure, PA banding was planned. Preoperatively, patient had saturation (SpO2) of 100% with FiO2of 0.5.
Intra-operatively, main pulmonary artery (MPA) was dilated with l-TGA relationship of great vessels. MPA was banded starting with the perimeter of 26 mm Hg while monitoring PA pressure distal to the band (Figure 2). With subsequent clipping, mean PA pressure of 10 mm Hg with SpO2 of 85 % was achieved. The gradient across the band was 55 mm Hg and visual contractility was good. Patient was shifted to ICU with minimal dose of milrinone.
After 3 hours post-operatively, patient developed sudden tachycardia, with ST segment elevation in the inferior leads (Figure 3). Apart from tachycardia, patient was hemodynamically stable. Subtle decompensation in the form of cold extremities, borderline urine output, lowering of saturation and increased lactate were observed. Chest X-ray revealed collapse of the left lung. TTE revealed mild ventricular dysfunction without any atrio-ventricular (AV) valve regurgitation. We never resorted to vasopressors. On the contrary, milrinone was maximized and aggressive diuresis was induced. Positive en expiratory pressure (PEEP) and total volume were regulated. Repeated suctioning and recruitment were done in view of left lung collapse. ST segment reverted back to baseline rhythm after few hours of these therapeutic adjustments (Figure 4). This correlated with gradual improvement in the cardiac output and patient was weaned off successfully.