Tracheo-Esophageal Fistula
Classification
Several, but Gross and Vogt classification systems most recognized. Classification systems describe anomalies of esophagus (blind pouch, stricture) and its aberrant relationship to trachea (proximal and or distal communication with trachea, multiple tracheal fistulas, etc.)
Incidence
1:3000-4500 live births. Esophageal atresia found in 85% of TEF presentations. Approximately 20% of neonates with TEF are premature with birth weights less than 2000g. More than 50% of neonates with TEF will have other anomalies. Cardiac findings such as VSD, TOF, ASD, and AV canal, are present in 20-30% and cardiac anomalies are associated with critical intra-operative events. Infants less than 2kg with cardiac disease presenting with TEF have survival rates less than 27%. A diagnosis of TEF should prompt evaluation for VACTERL (renal, anal, limb, cardiac, vertebral anomalies). TEF may present in association with Trisomy 18
Embryology
Primitive foregut diverticulum forms respiratory and digestive tracts, and divergence failure results in communication fistulas and aberrancy.
Anatomic findings
The predominant presentation of TEF is esophageal atresia with a blind pouch and fistula communication between the trachea and distal esophagus. Esophageal interruption with communication of the proximal esophagus to the trachea, tracheal communication through an esophageal pouch, and tracheal esophageal fistula without esophageal atresia are rarer. Isolated esophageal atresia without tracheal involvement can occur and, in this subgroup, other congenital anomalies show high prevalence. Tracheal fistulas are typically above carina, but approximately 10% are at or below carina. Multiple fistulas can also occur.
Clinical Presentation and Diagnosis
Prenatal polyhydramnios and absent stomach bubble may raise suspicion for TEF/EA. An infant unable to tolerate feeds due to choking suggests TEF/EA. Failure to pass NGT beyond 10cm or film showing placement in superior mediastinum at T2-T4 level is diagnostic of esophageal atresia. Presence of gas in stomach despite suspected OA indicates TEF.
Neonates with TEF often struggle to adequately clear secretions and may be temporized in a head up position with soft suction or placement of decompressive catheter in pouch
Recurrent pneumonia in the infant may lead to late recognition of TEF. This subset may have developed pulmonary insufficiency and poor lung compliance. Isolated TEF without esophageal atresia commonly presents late as silent aspiration is occult and discerned only after workup for recurrent respiratory insufficiency and/or pneumonia.
Preoperative evaluation and therapy
Repair of TEF proceeds urgently within the first few days of neonatal life to avoid respiratory compromise. A diagnosis of TEF/EA mandates strict NPO and decompression of the esophageal pouch. Evaluation for cardiac anomalies by echo and renal ultrasound should be obtained at a minimum; a full VACTERL assessment is helpful. Intravenous access should be established, and lab work obtained to determine hematocrit and the presence of metabolic acidosis.
Anesthetic management
Surgical plan may vary, impacting anesthesia management. In the setting of associated congenital anomalies, the order of procession is determined by acuity; congenital heart disease may require intervention first. TEF/EA can be addressed through an open right thoracotomy extrapleural approach or thoracoscopic intervention. Thoracoscopic techniques improve visualization and lessen surgical damage, but introduce higher intrathoracic pressures compromising ventilation and worsening acidosis in a setting already prone to challenges with carbon dioxide insufflation. A high right aortic arch requires a left sided approach.
The primary challenge for anesthetizing the neonate for TEF/EA is achieving adequate ventilation and avoiding gastric insufflation until the fistula is ligated. Historically, mask induction or cautious intravenous induction was recommended to maintain spontaneous ventilation, avoiding positive pressure engorging the stomach. Spontaneous ventilation is described as a sufficient anesthetic technique for both bronchoscopy, if used to first identify the fistula, and the primary open repair once intubated. Significant desaturations may occur requiring high pressure ventilation, that either recover the neonate or evolve into emergent gastrostomy and/or fistula ligation.
Intubation with the distal tube placed beyond the fistula, generally at the carina, or with the ETT bevel positioned anteriorly, can minimize fistula insufflation. In the event of sudden ventilatory failure following intubation, suspect intubation of the TOF. Small adjustment in ETT depth may rescue.
The use of muscle relaxants, either to optimize intubation or to improve thoracic compliance during one lung ventilation, is readily described in case series. Small fistulas (3mm) are unlikely to facilitate large volume gastric insufflation. Some centers routinely occlude large fistulas with Fogarty catheters during bronchoscopy, facilitating the use of muscle relaxants to optimize ventilation during surgical repair. The trend toward thorascopic repair presumes wider use of positive pressure ventilation and/or muscle relaxation as thoracic insufflation can acutely decompensate the chest wall work capacity of a neonate.
A TEF with a long gap esophageal atresia may necessitate a two staged repair (Foker), where the proximal pouch is externalized with traction to promote lengthening, and a gastrostomy is placed for feeding. The interim period of growth requires prolonged sedation and ventilation. Paravertebral nerve catheters and epidural catheters are analgesic strategies that may be employed to reduce opioid and benzodiazepine requirements.
Monitoring, vascular access
Standard ASA monitoring is recommended. Arterial monitoring can be of particular use to assess significant acidosis during repair. Early extubation is often advantageous to minimize air pressure transgression on the surgical repair, but accumulated acidosis from a lengthy repair may pause this transition allowing for postoperative ventilation support to correct the respiratory component of acidosis, and improved hemodynamics.
Postoperative Management
Neonates may remain intubated postoperatively to be gently weaned in the neonatal ICU. Prematurity, LBW, and other congenital anomalies may prolong ventilatory needs. Infants >2.5 kg with no other known anomalies may be candidates for extubation at surgery conclusion.
Morbidity and mortality
Survivability is robust, with overall mortality less than 10%. Prematurity, LBW, and cardiac anomalies are associated with poorer outcomes.
Morbidity rates however are high. Repairs are complicated by a high risk of esophageal stricture, with risks of anastomotic leak, recurrent fistula, and vocal cord paralysis less frequent but still significant.
References
Perioperative management and outcomes of esophageal atresia and tracheoesophageal fistula
Tracheo-oesophageal fistula (TOF) and oesophageal atresia (OA)
https://videolibrary.globalcastmd.com/thoracoscopic-esophageal-atresia