Procedure Choose the largest size tube feasible to perform the indicated task, without causing undue discomfort to the child In general, an 8Fr tube can be used in the newborn and a 12Fr tube by the age of year A teenager will usually tolerate an 18Fr tube For ages in between, choose the size accordingly A good rule of thumb is that the NG tube size is generally twice the size of the endotracheal tube Endotracheal tube size can be estimated as (age in years/4) + In an adolescent overdose, the use of a 28 to 40Fr tube will assist in the efficient removal of pill fragments from the stomach, but the practice of gastric emptying has become uncommon in the management of medication overdoses Estimate the length of tubing to be inserted by adding to 10 cm to the distance from the nares to the xiphoid process ( Fig 130.27 ) Prepare the child by explaining the procedure; sedation is rarely required Older children who are alert can remain sitting Infants and obtunded children require the supine position with their head turned to the side Topical anesthetic spray can be applied to the posterior oropharynx to decrease gagging Straighten the curved tube and check its patency with a syringe Apply sterile, water-based lubricant or lidocaine gel to facilitate nasal passage Grasp the tube to cm from the distal end and advance it posteriorly along the floor of the nose If it is incorrectly directed up the nose, the tube may lacerate the inferior turbinate Insert it with the natural curve of the tube pointing downward to pass the bend of the posterior pharynx A cooperative child can be asked to flex his/her head slightly and to swallow some water to assist in glottic closure and easy passage into the esophagus An assistant should flex the infant’s neck If the child coughs and gags persistently or if the tube emerges from the mouth, temporarily discontinue the procedure and support the child until they recover from the episode When the tube is successfully inserted to the measured length, check its position Attach a syringe filled with air to the proximal end and, while depressing the plunger rapidly, listen with a stethoscope for gurgling over the stomach Additional confirmatory tests in high-risk patients that should be considered prior to use include pH testing of gastric contents (pH should be less than 4) or a single frontal view of the chest including the upper abdomen to confirm tube tip position within the stomach Tape the tube securely to the nose, using tincture of benzoin on the skin in the uncooperative or diaphoretic child