FRCA Notes

Tracheo-Oesophageal Fistula and Oesophageal Atresia

This topic is explicitly mentioned in the old intermediate curriculum ("...implications for anaesthesia of major congenital abnormalities (e.g. tracheosophageal fistula)...") but is yet to form the basis of a CRQ.

Resources

  • Oesophageal atresia (OA) and tracheo-oesophageal fistula (TOF) are inter-related congenital conditions with an incidence of 1 in 3,000 - 5,000 births
    • 30% are premature
    • 50% have another associated anomaly

  • OA can occur in isolation, but is more commonly associated with a communication between the oesophagus and the trachea i.e. TOF
  • The trachea and oesophagus develop from a common foregut tube during the 4th - 5th week of gestation and failure of normal separation results in these defects
  • Care requires a multidisciplinary approach, with close communication between surgeon and anaesthetist owing to the shared airway

Gross (anatomical) classification

  • Describes the anatomical variations of TOF ± OA; the most common lesion is OA with a distal TOF
  • More comprehensive classifications describe up to 10 subtypes, including rarer defects such as laryngo-tracheo-oesophageal clefts and tracheal agenesis

Gross type Anatomy Incidence
A Isolated OA; no fistula 7 - 8%
B OA with proximal TOF 1 - 4%
C OA with distal TOF 85%
D OA with proximal and distal TOF 3 - 4%
E 'H-type' TOF without OA 3 - 4%

Spitz classification

  • Prognostic classification based on birth weight and presence of cardiac disease

Group Features Survival rate
I Birth wt. >1.5kg and no major cardiac anomaly 98.5%
II Birth wt. <1.5kg or major cardiac anomaly 82%
III Birth wt. <1.5kg and major cardiac anomaly 50%


  • No proven aetiology; several theories exist:
    • Genetic e.g. defective sonic hedgehog gene; twin concordance of 2.5%
    • Molecular e.g. abnormal interaction between retinoic acid and growth factors
    • Environmental i.e. maternal risk factors including diabetes, smoking, alcohol and advanced maternal age

Associations

  • ∽50% of infants with OA/TOF have associated congenital anomalies, including:
    • Congenital cardiac disease (35%) e.g. VSD, PDA, ASD, tetralogy of Fallot, right-sided aortic arch
    • VACTERL association (25%): Vertebral, Anorectal, Cardiac, TOF, Renal and Limb anomalies
    • Renal anomalies e.g. renal agenesis, polycystic kidney
    • Duodenal atresia
    • CHARGE syndrome
    • Trisomy 13, 18 and 21
    • DiGeorge syndrome
    • Treacher-Collins syndrome

Antenatal

  • Antenatal diagnosis is uncommon; ultrasound markers reflect impaired fetal swallowing of amniotic fluid:
    • Polyhydramnios
    • Small or absent stomach bubble
    • Large oesophageal pouch
  • Detection of other anomalies e.g. VACTERL increases the likelihood of OA/TOF
  • If detected antenatally, delivery should take place in a specialist centre with neonatal surgical facilities; early diagnosis prevents inadvertent feeding and aspiration

Postnatal

  • More commonly presents postnatally, with clinical features of:
    • Excessive salivation and difficulty clearing secretions
    • Repeated episodes of coughing/choking
    • Choking, cyanosis and respiratory distress with feeding
    • Aspiration pneumonia ± sepsis

  • Diagnosis is confirmed by:
    • Inability to pass an NG tube more than ∽10cm into the oesophagus
    • Chest and abdominal radiograph demonstrating a coiled tube in the blind upper pouch
      • Gas in the stomach indicates a distal TOF; a gasless abdomen suggests isolated OA
      • The whole abdomen should be imaged to look for duodenal atresia, which should be corrected at the same operation

  • OA ± TOF is rarely a surgical emergency; surgery is usually performed in daytime hours within the first few days of life, with senior staff available
  • Referral and transfer to a specialist neonatal surgical centre, with care in a level 2 (high-dependency) setting in the meantime
  • Tracheal intubation for stabilisation or transfer should be avoided where possible owing to the risk of gastric inflation via the fistula

Initial stabilisation

  • The aim is to prevent aspiration of saliva and gastric contents:
    • Stop all oral feeding
    • Head-up positioning
    • Supplemental oxygen if saturations are low
    • Replogle tube on continuous low-pressure suction
    • IV maintenance fluids containing glucose
    • ± H2RA

  • Replogle tube:
    • Double-lumen tube placed in the upper oesophageal pouch
    • One lumen allows continuous suction; the other is an air vent to prevent blockage, which can also be used for flushing
    • If unavailable, deep pharyngeal suction with a soft catheter to 10cm every 5 mins

  • Emergency fistula ligation is only indicated where gastric insufflation leads to desaturation and decompensation

Surgical repair

  • The fistula is identified and ligated, the trachea repaired, then the upper and lower oesophageal pouches are mobilised and a primary anastomosis performed
  • The surgeon passes a transanastomotic tube (TAT) to allow early post-operative feeding

  • Surgical retraction or compression of the mediastinum and lung can cause:
    • Desaturation, which may require manual ventilation and/or recruitment manoeuvres
    • Reduced cardiac output
    • Kinking or compression of the tracheal tube

  • Open thoracotomy repair:
    • Right posterolateral thoracotomy using an extrapleural approach
    • Lung is retracted rather than deflated; any anastomotic leak drains without contaminating the pleural cavity, reducing the risk of empyema
  • Thoracoscopic repair:
    • Transpleural approach; requires the neonate to tolerate lung collapse/one-lung ventilation

Advantages of thoracoscopic repair Disadvantages of thoracoscopic repair
Shorter duration of post-operative ventilation Requires tolerance of one-lung ventilation
Reduced opioid requirement Not suitable for extreme prematurity or low birth weight (<2kg)
Earlier establishment of oral feeds Not suitable if haemodynamically unstable
Reduced blood loss and possibly shorter length of stay Transpleural approach means leaks drain into the pleural cavity
Avoids musculoskeletal sequelae of thoracotomy e.g. scoliosis

  • There is no significant difference in overall complication, leak or stricture rates between open and thoracoscopic approaches

Gap assessment

  • The 'gap' is the distance between the upper and lower oesophageal pouches
  • Short gap (<3 vertebral bodies): amenable to primary anastomosis
  • Long gap (>3 vertebral bodies): staged repair
    • The native oesophagus is the preferred conduit, so traction sutures are used to elongate the pouches over time e.g. Foker technique
    • Initial gastrostomy for feeding ± oesophagostomy to drain secretions without the need for a Replogle tube

Perioperative management of the neonate undergoing tracheo-oesophageal fistula repair


History and examination

  • General principles of neonatal anaesthesia apply
  • Gestational age, birth weight and associated anomalies, particularly cardiac
  • Evidence of aspiration e.g. oxygen requirement, respiratory distress

Investigations

  • Chest and abdominal radiograph to confirm Replogle tube position and assess for aspiration
  • Echocardiogram to identify cardiac anomalies
    • A right-sided aortic arch may alter the side of the surgical approach
  • Renal ultrasound e.g. VACTERL association
  • FBC, U&E
  • Point-of-care glucose and electrolytes
  • Cross-match: one adult unit of packed red cells available before surgery
  • If lumbar/sacral dimple, image the spine to ensure normal anatomy prior to neuraxial analgesia

Optimisation

  • Correction of fluid deficit
  • Correction of hypoglycaemia and electrolyte imbalance
  • Vitamin K prophylaxis
  • Antibiotics if evidence of aspiration
  • Ongoing Replogle suction and head-up positioning to minimise aspiration

  • Requires close communication with surgeons owing to the shared airway
  • Induce in the operating theatre with all equipment ready; forced-air warming applied early to maintain normothermia

Monitoring and access

  • AAGBI monitoring; pulse oximetry preferably on the right hand i.e. pre-ductal
  • ± NIRS: cerebral (forehead) and splanchnic (subcostal) probes, with baseline readings obtained early
  • Additional large-bore IV access for fluids and blood products
  • Arterial line in the non-dependent radial artery to avoid compression during positioning; allows regular blood gas sampling
  • ± Central venous access e.g. femoral, IJ or PICC
    • Site guided by the surgical approach; avoid the right IJ if a supraclavicular approach is planned

Induction

  • The aim is to maintain spontaneous ventilation and avoid positive pressure ventilation until the fistula is controlled, to prevent gastric inflation via the fistula
  • Inhalational induction with sevoflurane in oxygen, avoiding nitrous oxide
  • Topical lidocaine to the larynx and trachea (max. 5mg/kg) to reduce coughing and airway reflexes during bronchoscopy
  • Depth maintained with volatile via a nasopharyngeal tube, or propofol ± remifentanil
  • High-flow nasal oxygen is a useful adjunct to reduce desaturation during bronchoscopy

Bronchoscopy and fistula localisation

  • Rigid or flexible bronchoscopy confirms the diagnosis, the position and size of the fistula, and identifies any additional fistulae
  • Spontaneous ventilation is possible via the ventilating side port of a rigid bronchoscope
  • Once identified, the fistula may be:
    • Cannulated with a guidewire to aid surgical identification
    • Occluded with a 3 - 4F Fogarty catheter, which must be secured as dislodgement into the trachea can completely obstruct ventilation

Tracheal intubation

  • Performed after localisation of the fistula; blind intubation risks intubating the fistula and should be avoided
  • A 3.0 - 3.5mm tracheal tube is placed with the tip distal to the fistula:
    • Traditional technique: intentional endobronchial intubation, then withdraw until bilateral breath sounds are heard
    • Bevel facing anteriorly so that the posterior wall of the tube occludes the fistula
  • Carinal or bronchial fistulae may require endobronchial intubation and one-lung ventilation, or Fogarty occlusion, until ligation

Positioning

  • Open repair: left lateral position i.e. right side up, with a roll under the chest
  • Thoracoscopic repair: almost prone over a chest roll, arms above the head, table tilted 30° to the left
  • Careful padding; recheck tube position after positioning

Maintenance and ventilation

  • Volatile with short-acting opioid infusion e.g. remifentanil or fentanyl; longer-acting opioid at the end
  • Spontaneous ventilation minimises leak through the fistula but may be hard to sustain; IPPV ± neuromuscular blockade risks gastric inflation if the fistula is not occluded
  • Hand ventilation may be needed during surgical retraction; high FiO2 and permissive hypercapnia may be required
  • Rescue manual ventilation and suction must be immediately available
  • Regular 'sit-reps' between anaesthetist and surgeon to review gas exchange, ventilator pressures and vital signs
  • Fistula ligation is a key point to pause; if the neonate is unstable, acidotic or hypoxic, the procedure may need to be abandoned

Analgesia

  • Multimodal; options include:
    • Opioid-only technique
    • Caudal epidural catheter threaded to thoracic level under ultrasound guidance
    • Paravertebral block ± catheter

Gastric inflation

  • A significant risk until the fistula is ligated; caused by positive pressure ventilation or intubation of the fistula
  • Leads to splinting of the diaphragm, inability to ventilate and cardiovascular compromise
  • Pre-operative gastrostomy can decompress the stomach, but creates a low-resistance leak that may make ventilation ineffective
  • In an emergency, life-threatening distension can be treated by needle decompression of the stomach via the left upper quadrant

Transanastomotic tube

  • Soft feeding tube placed across the anastomosis to allow early feeding
  • Can be passed nasally into the upper pouch through a split 3.0mm uncuffed tracheal tube, which acts as an introducer and a marker for the surgeon; the surgeon then guides the TAT into the stomach
  • Must be well secured and clearly labelled; it should not be replaced blindly if dislodged

  • Care in NICU (level 3) or a high-dependency (level 2) setting
  • Ongoing ventilation may be required, although early extubation is possible if the repair is satisfactory and there is no other indication for ventilation
  • Multimodal analgesia e.g. opioid infusion with regional technique
  • IV fluids, with early re-establishment of feeds via the TAT
  • Regular suctioning of the upper pouch/pharynx
  • Antibiotics for 48hrs
  • Monitor for complications (see below)

  • Overall 30-day mortality is ∽1 - 2%; risk is higher with prematurity (<32 weeks) and congenital heart disease

Early

  • Anastomotic leak (8 - 20%)
    • Presents as pneumothorax or saliva in the chest drain
    • Usually managed conservatively
    • Increases the risk of later stricture
  • Electrolyte imbalance
  • Lung collapse
  • Oedema from fluid shifts
  • Stridor from airway oedema after prolonged intubation

Late

  • Gastro-oesophageal reflux (30 - 70%)
    • The most common long-term problem; reflects abnormal oesophageal motility and impaired lower oesophageal sphincter tone
    • Managed with H2RA, PPI, prokinetics; a significant proportion will require fundoplication
  • Anastomotic stricture; may require repeated dilatation
  • Oesophageal dysmotility and feeding difficulties
  • Tracheomalacia
  • Recurrent aspiration and pneumonia
  • Recurrent TOF (∽8 - 10%)
  • After thoracotomy: rib deformity, hemithoracic hypoplasia, winging of the scapula and scoliosis