A newborn baby had normal APGAR score at birth and developed excessive frothing and choking on attempted feeds. The investigation of choice is –

This is a case of tracheo esophageal fistula. C/F of tracheo esophageal fistula — The newborn regurgitates all of its first and subsequent feeds. Saliva pours almost continuously from the mouth of the infant (This is 'the sign' of tracheoesophageal atresia. It does not occur in any other condition) Attacks of coughing and cyanosis occur on feeding. Clinical confirmation of diagnoses If a nasogastric tube is tried to pass into the infant it will come against an obstruction within 10 cm. If this occurs the diagnosis is virtually certain. Radiological confirmation of diagnosis — A lateral chest X-ray → It shows a lucent proximal pouch that may displace trachea anteriorly. X-ray abdomen → Gas in the stomach is seen if there is communication between the lower part of the oesophagus and trachea which occurs in the commonest variety of tracheo-oesophagal fistula.