Soru

Parents arrive at an urgent care clinic holding their 8-month-old infant, who appears profoundly blue and is crying inconsolably. The family recently immigrated and the child's medical records are unavailable, but the parents mention a doctor once heard a 'hole in the heart'. Vital signs show severe hypoxia with an oxygen saturation of 65% on room air. Physical examination reveals deep central cyanosis and a remarkably quiet precordium with only a faint systolic murmur at the left upper sternal border. The physician identifies a hypercyanotic spell secondary to a right ventricular outflow tract obstruction. Arrange the appropriate acute management steps for this condition in the correct sequential order, from initial first-line intervention to therapy for refractory symptoms.