Tracheoesophageal Fistula 　　　　　　R2趙怡芳/VS范守仁

Epidemiology Incidence: 1/4000 30-50%: congenital anomalies (35% cardiac; 30% musculoskeletal) 20-30%: premature, BW<2000g VACTERAL and VATER syndrome: Vertebral anomalies: Anal: imperforate anus Cardiac: VSD, PDA, TOF, coarction of aorta, ASD Trachea: TEF Esophageal: EA Renal: renal agenesis,ureteral abnormalities, hypospadias Limb: polydactyly, wrist/knee anomalies

Embryology Esophagus and tracheal originate from the median ventral diverticulum of the forgut, separated by esophagotracheal septum TEF: esophageal and tracheal failure to separate during divison of the endoderm Esophageal atresia: tracheal structure assume most of the endoderm

Types of TEF

Diagnosis During pregnancy: maternal polyhydramnios and premature labor Newborn: s/s: cough, chocking, cynosis, excessive salivation, drooling, OG tube: inability to pass down the esophagus into the stomach X-ray: catheter curled up in the upper pouch of the esophagus air/gas bubbles in the stomach and intestine ultrasonography: diagnosis of any associated cardiac, musculoskeletal, GI or GU abnormalities

General management Primary repair of TEF is urgent Associated anomalies: CV, GU, musculoskeletal Protect the lungs from aspiration pneumonia Avoidance of feeding Positioning of the infant slightly head up to minimize regurgitation of gastric contents through fistula Intermittent suction Antibiotic therapy and physiotherapy in babies with contaminated lung

Surgical management One stage repair: optimal surgical management Fistula is ligated, proximal and distal ends of the esophagus are anastomosed Right posterolateral extrapleural thoracotomy Left thoracotomy if the p’t has right aortic arch Gastrostomy: High risk infants unable to withstand a thoracotomy Decompress the stomach and prevent regurgitation via fistula into the lungs Local anesthesia: general anesthesia: protect the lungs from aspiration during surgical manipulation

Surgical Managment Definitive repair 24-72 hours later, when infant can withstand both surgery and anesthesia Method: right thoracotomy using a posterolateral extrapleural approach Fistula is ligated, esophageal segments are anastomosed If distal esophagus is too short Fistula is ligated exteriorization of the upper pouch through an esophagostomy is performed wait till weight of 9kg or 1 y/o to perform anastomosis

Anesthetic Management Operating room set up: “keep warm”: warm room, blanket, overhead warmer Release NE: vasoconstriction, increases metabolism, change degree of shunting Affect anesthetic agents: likely overdosage, postop hypoventilation, apnea Coagulopathy, metabolic acidosis Standard monitoring: EKG, pulse oximetry, end tidal CO2, BP monitoring (A line in high risk infants), U/O

Anesthetic Management Induction: “establish airway without pulmonary aspiration or gastric distension” Suction, pre-oxygenation Maintain spontaneous ventilation: Avoid positive pressure ventilation: Insufflation of the stomach via the fistula or loss of ventilation through the gastrostomy Gastric distention: compromise ventilation, aspiration

Anesthetic Management Intubation/Airway Awake intubation Safe Appropriate positiong of ETT w/o positive pressure ventilation Difficult and traumatic in vigorous infants Inhalation/IV anesthetic +/- muscle relaxant: Aware of positive pressure ventilation Avoid excessive insufflation of the stomach via fistula Maintain spontaneous ventilation: With assistance ventilation until fistula is ligated Keep airway pressure low (10-15 cmH20)

Anesthetic Management: Intubation/Airway ETT position Below the fistula and above the carina Right mainstem intubation, then withdraw Proximal to carina, bevel facing anteriorly so that posterior wall can occlude the fistula Confirmation Fiberoptic bronchoscopy Gastrostomy to water seal

Anesthetic Management Occlusion of fistula: Fogarty catheter via bronchoscope or gastrostomy Intraop problems: One lung ventilation: hypoxia, CO2 retension ETT obstruction: blood clot, secretion, kinking of trachea Vagal response: tracheal manipulation, lead to bradycardia

Anesthetic Management: Postoperative problems Post op extubation is desired, better suture line healing 1) degree of pulmonary dysfunction 2) presence of associated anomalies Post op ventilation Conditions: Defective tracheal wall at the site of fistula Contaminated lung Problems associated with prematurity or associated anomalies ETT positioned >1cm away from site of fistula repair Distance btw lip and site of esophageal repair measured, avoid suction too deep

References Smith’s Anesthesia for Infants and Children, 6th edition, 1996 Mosby Clinical Cases in Anesthesia, 3rd edition, 2005 Elsevier Pediatric Anesthsia:The Requisites in Anesthesiology, 2004 Mosby Elsevier Yao & Artusio’s Anesthesiology; Problem Oriented Patient Management, 5th edition, 2003 Lippincott

Questions What are preoperative concerns in a patient with TEF? How will you induce and maintain general anesthesia? During ligation of the fistula, the infant’s oxygen saturation decreases to 86%, what will you do? Will you extubate at the end of the surgery? Why or why not?