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.