What the Anesthesiologist Should Know before the Operative Procedure
Tracheo-esophageal fistula (TEF) with or without esophageal atresia (EA) and isolated esophageal atresia occur in about 1 in 2,500 to 1/4,000 live births. They represent a group of anomalies that illustrate the common origin of the upper respiratory tract and the foregut. There are five anatomic variants and they are described by two different classification systems. Proximal esophageal atresia with a distal fistula (Gross C) is the most common, representing over 85% of all cases. See Figure 1.
The genetics of the disease are incompletely understood. Trisomy 18, along with other chromosomal anomalies (Trisomies 13 and 21), may account for 6% to 10% of cases. Maternal use of methimazole for hyperthyroidism has been reported in two cases.
TEF/EA can be suspected prenatally. Polyhydramnios and absent in-utero visualization of a stomach bubble on ultrasound (isolated EA) are suggestive of TEF/EA. Frequently, the condition is suspected only after a newborn presents with feeding intolerance. Failure to pass a naso/orogastric tube into the stomach is highly suggestive. An X-ray will demonstrate coiling of the tube in the proximal pouch in type C TEF/EA. A small amount of contrast injected via the tube will demonstrate pooling in the pouch. This is generally avoided because of the risk of aspiration. Inability to pass a naso/orogastic tube along with an X-ray, demonstrating coiling of the tube in the upper thorax along with air in the stomach, confirms the diagnosis of a type C defect with EA and a distal TEF.
Isolated TEF may present later with recurrent pneumonias or silent episodes of aspiration.
1. What is the urgency of the surgery?
What is the risk of delay in order to obtain additional preoperative information?
The diagnosis and proper management of infants with EA/TEF is always urgent. Surgical correction of EA/TOF (Tetralogy of Fallot) is performed soon after the diagnosis is made. It can be emergent or urgent but can usually wait for complete preoperative evaluation, stabilization and transfer to a tertiary pediatric center.
Emergent surgeryis required when the infant has significant respiratory compromise. Prematurity, gastric secretions entering the lungs via fistula and gastric distention from positive pressure ventilation can all lead to worsening respiratory distress. Poorly compliant lungs as a result of immaturity or pneumonitis coupled with a large fistula set the stage for the sickest infants. If the stomach is grossly distended, an emergency bedside gastrostomy may be performed. This will decompress the stomach but may make ventilation even more difficult as positive pressure ventilation may be directed through the fistula and out the gastrostomy rather than to the lungs. Partial occlusion of the gastrostomy (by the application of an adjustable pop-off device to the end of the gastrostomy tube) has been used successfully for short-term management. Today, most of these infants should be taken emergently to the operating room for fistula ligation. The esophageal atresia repair can be deferred until the infant has stabilized.
Infants that do not require positive pressure respiratory support or that tolerate gentle positive pressure ventilation can have their surgery delayed until a thorough preoperative evaluation has been completed. Most infants will have their surgery in the first couple of days of life. Preoperatively infants are frequently nursed in a prone, 30-degree head up position to minimize the risk of aspiration. With EA, frequent or continuous oral suctioning is necessary to minimize aspiration of oral secretions.
2. Preoperative evaluation
About 50% of cases of EA/TOF are associated with other congenital defects. About 30% of newborns with EA/TOF will have three or more defects described in the VACTERL association of defects (see Table I). About 30% will have congenital heart disease with ventricular septal defects and TOF being most common. About a quarter of infants will be born prematurely.
|V||Vertebral anomalies (hemivertebra or absent vertebra)|
|A||Anorectal anomalies, imperforate anus|
|C||Cardiac lesions, TOF, VSD (ventricular septal defect) and ASD (atrial septal defect), single umbilical artery|
|TE||Tracheoesophageal fistulas and esophageal atresia|
|R||Hypoplasia, hypdronephosis, reflux|
|L||Radial limb defects such as absent or abnormal thumbs, absent radius, unilateral or bilateral|
Most infants also have poor growth and are small
3. What are the implications of co-existing disease on perioperative care?
b. Cardiovascular system
Because of the high prevalence of congenital heart disease, a bedside preoperative echocardiogram is essential. Perioperative care will need to take into account the implications of cardiac lesions that can result in under-perfusion (right to left shunts – TOF) or over-perfusion (left to right shunts – VSD) of the lungs. It is important to determine which side the aortic arch is on as 25% of patients with TOF will have a right sided arch. This will often determine whether the repair will be done through a right (usual) or left thoracotomy.
The infant will require a careful assessment of their respiratory status as it relates to prematurity and possible aspiration pneumonitis. If intubated, the size and depth of the endotracheal tube (ETT) should be noted. Ventilator settings and a recent blood gas analysis should be reviewed as should the lung fields on chest X-ray.
Infants with Vacterl association may have renal abnormalities such as absent kidney, hydronephrosis, and reflux. An abdominal ultrasound and baseline serum creatinine and electrolytes are recommended to assess renal status. Neonates, especially if born prematurely, have both reduced GFR (glomerular filtration rate) and urine concentrating ability. These factors need to be considered when deciding on fluid replacement therapy.
All infants with TEF/EA should be NPO (nothing by mouth) preoperatively and are nursed in a 30-degree head-up position with continuous or intermittent pharyngeal suction.
g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)
4. What are the patient's medications and how should they be managed in the perioperative period?
Neonates coming for TEF/EA repair may be on a number of medications. Frequently, they are on a high dextrose infusion or total parenteral nutrition (TPN). This is usually continued intraoperatively. Discontinuing all glucose containing parenteral fluids will predispose the infant to hypoglycemia. They may also be on antibiotic therapy which may or may not need to be redosed intraoperatively. If the infant has a ductal-dependent cardiac lesion, a prostaglandin infusion may be present. This also should be continued intraoperatively.
h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
i. What should be recommended with regard to continuation of medications taken chronically?
j. How To modify care for patients with known allergies –
k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.
If the infant has significant urologic issues such that prolonged or frequent bladder catheterization may be required, then some centers will place these children on “latex precautions” to minimize the chances that they will become latex allergic. This is becoming less of a problem now that more latex-free medical products are in use. Many facilities are working on becoming latex-free.
l. Does the patient have any antibiotic allergies- [Tier 2- Common antibiotic allergies and alternative antibiotics]
m. Does the patient have a history of allergy to anesthesia?
5. What laboratory tests should be obtained and has everything been reviewed?
In general, laboratory tests needed preoperatively are similar to those for any neonate coming for surgery. CBC (complete blood count) with platelet count, electrolytes and arterial blood gas (if respiratory compromise suspected) should be obtained. Banked blood should be set up for possible transfusion. A CXR (chest x-ray), cardiac echo and abdominal ultrasound should be obtained when feasible for reasons outlined above. Premature infants may need a head ultrasound to rule an intraventricular hemorrhage (IVH).
Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
All of these repairs are done under general anesthesia, except for the relatively rare instance of a bed side gastrostomy. Inhalation or intravenous anesthesia can be used. Frequently, a combination is preferred. For hemodynamically unstable patients, a narcotic relaxant technique is usually preferable. The majority of repairs are performed through a right thoracotomy unless the patient has a right-sided aortic arch, in which case a left thoracotomy may be used.
Infants are usually ventilated for a day or more postoperatively. Occasionally, term infants, especially if they only had an isolated fistula ligation, will be extubated in the immediate postoperative period. For these patients, a regional technique such as an epidural catheter may be used.
The challenge for managing these patient centers primarily on airway management and balancing adequate ventilation and oxygenation with pulmonary compliance and fistula size. For infants that arrive to the operating room unintubated, anesthesia is frequently induced with the maintenance of spontaneous ventilation to avoid gastric distention. Some practitioners will maintain spontaneous ventilation until the chest is opened. Others, as is my preference, will provide gentle positive pressure. If this does not result in significant gastric distention, then intubation with or without muscle relaxation can be performed.
There are multiple recommendations for endotracheal tube (ETT) placement. Because the fistula is most commonly above the carina along the posterior tracheal wall, some clinicians with intentionally intubate a mainstem bronchus (usually right), then slowly pull back the ETT until bilateral breath sounds are heard. Rotating the ETT 90 degrees can place the bevel of the ETT anteriorly with the longer end of the ETT facing posteriorly. Unless a “murphy eye” is present, this will help to ensure ventilation of the lungs with at least partial occlusion of the fistula.
Theoretically, this technique should work well but maintaining the correct position of the ETT can be difficult. It can migrate into a mainstem bronchus or worse, into the fistula itself. In about a third of cases, the fistula will be too close to the carina or actually come off a mainstem bronchus, making safe placement of the ETT in this manner unsafe or difficult. If gastric distention is a problem, intentional mainstem intubation (usually left) can be tried. If the infant will tolerate this, the anesthesiologist can ventilate with little fear of further gastric distention. For a thoracoscopic approach. this can provide one-lung ventilation although adequate exposure can often be achieved with simple CO2 insufflation of the operative hemithorax.
Other techniques that have been used to manage infants with large fistulas and or noncompliant lungs include bronchoscopically (rigid or flexible) assisted placement of a small (2 or 3 French) Fogarty embolectomy catheter through the fistula. The balloon is inflated in the stomach and occlusion of the fistula is maintained by gentle backward traction on the catheter.
Another technique is retrograde placement (through a gastrostomy) of a similar balloon occlusion catheter in the fistula itself. Correct positioning is difficult and displacement is a problem, especially with the retrograde technique. Migration of the balloon from the fistula into the trachea can result in complete airway occlusion. These methods are best reserved for instances when less invasive methods fail to provide adequate ventilation and/or oxygenation.
A flexible fiberoptic bronchoscope (FFB) can be used to perform tracheoscopy through the ETT. It can be used initially to locate the fistula and confirm its position and size. In the case of a high fistula, the ETT may need to be pulled back in order to visualize it. Also, gentle sustained positive end expiratory pressure (PEEP) may open a collapsed fistula and make it easier to see. Once the fistula is identified, the FFB can help confirm placement of the ETT distal to the fistula if that is necessary. The fiberoptic scope can also be used intraoperatively to assist the surgeon. Deliberate placement of the FFB tip in the fistula will help the surgeon identify a fistula that is hard to find in the surgical field. Dimming the overhead OR lighting will allow the surgeon to see the “glow” of the FFB light in the fistula.
6. What is the author's preferred method of anesthesia technique and why?
My preference for anesthesia is a gentle intravenous (propofol/narcotic) or inhalation induction (sevoflurane). If gentle positive pressure ventilation is tolerated, then I will go ahead and administer a muscle relaxant and proceed with intubation.
I will initially place the ETT high (above the fistula) as long as ventilation is adequate. As outline above, this will allow fiberoptic examination of the trachea and identification of the location and size of the fistula. Manipulation of the position of the ETT will depend on the location of the fistula and the adequacy of ventilation.
Before the surgery begins, I usually require that 2 peripheral intravenous catheters (IVs) and an arterial catheter are in place. A left precordial stethoscope is useful in assessing intraoperative ventilation. Continuous ECG, pulse oximetry and capnography are essential. These monitors, along with intermittent arterial blood gas analysis, will guide your ventilation management. If the infant is deemed at risk for cardiac shunting or transitional circulation, then both preductal (e.g., right hand) and postductal (e.g., a foot) pulse oximetry should be monitored.
For a typical type C TEF/EA, the surgeon will approach the repair from a right thoracotomy. The lung will be retracted and this can result in impaired oxygenation and ventilation. Communication with the surgical team is essential. Sudden changes in the patient’s oxygenation, capnogram, pulmonary compliance or blood pressure should prompt an investigation. Surgical manipulations can result in airway obstruction, cardiac or great vessel compression. Occlusion of the azygos vein can result in significant compromise of venous return from the lower half of the body in the setting of an interrupted inferior vena cava. ETT migration into the fistula will be life threatening if not recognized. Unstable patients may require frequent breaks from surgical manipulation in order to re-establish adequate oxygenation, ventilation or perfusion.
The anesthesiologist and surgeon must communicate continuously. Intermittent “breaks” may be required with removal of all lung retraction and the atelectactic lung is re-expanded and ventilated. After a short period of improved oxygenation, the surgery is allowed to resume. Higher peak airway pressures are less of a problem after the fistula is ligated and gastric distention is no longer an issue. The surgeon will frequently instill saline in the chest after the fistula is ligated and ask the anesthesiologist to provide sustained positive pressure. A lack of bubbles assures that the fistula is closed to the mediastinum.
As the surgeon locates the ends of the esophagus, the anesthesiologist will frequently be asked to advance an orogastric tube or esophageal stethoscope into the end of proximal pouch. This will help the surgeon identify this portion of the esophagus. A primary repair may not be possible if the ends cannot be approximated. A cervical esophagostomy may be performed to drain oral sections and minimize aspiration risk.
The child may return to the OR after attempts to stretch the proximal esophagus or if the ends remain far apart, they may return at a later date for an interposition graft or gastroesophageal anastomosis. If the ends can be approximated, then the repair is usually completed after a nasogastric tube has been placed across the nearly finished esophageal anastomosis. This tube will allow early enteral feeding. Should the tube accidentally become dislodged, replacement should not be attempted since blind attempts may cause disruption of the anastomosis.
b. If the patient is intubated, are there any special criteria for extubation?
For term infants having undergone a straightforward repair, early extubation is a consideration. Most infants are left intubated for a day or more, and narcotic administration can be liberalized during this time. Issues of prematurity, residual lung disease, tension on the esophageal anastomosis, and other comorbidities all have to be taken into consideration prior to extubation.
c. Postoperative management
Adequate analgesia can be provided with a continuous epidural infusion. Dilute local anesthetics and narcotics have been used. Alternatives to epidural analgesia include local infiltration, rib blocks and paravertebral blocks. Intravenous narcotics are very effective but need to be carefully titrated to avoid respiratory depression.
As noted elsewhere, care should be taken when instrumenting the airway and the esophagus. An endotracheal tube can end up with the tip wedging into a residual blind pouch. This will impede ventilation and can result in tracheal rupture. The ETT should be positioned with the tip well away from the fistula site. Blindly passing a feeding tube in the first week or so after repair may disrupt an esophageal anastomosis.
These babies frequently have a degree of laryngomalacia and tracheomalacia that can contribute to stridor and chronic aspiration. Gastroesophageal reflux is also common. Finally, some of these infants develop esophageal strictures resulting in feeding intolerance. They may require multiple trips to the operating room for balloon dilations.
What's the Evidence?
Broemling, N, Campbell, F. “Anesthetic management of congenital tracheoesophageal fistula”. Paediatr Anaesth. vol. 21. 2011 Nov. pp. 1092-9. (Good general review article.)
Knottenbelt, G, Skinner, A, Seefelder, C. ” Tracheo-oesophageal fistula (TOF) and oesophageal atresia (OA)”. Best Pract Res Clin Anesthesiol. vol. 24. 2010 Sept. pp. 387-401. (Excellent review of intraoperative management.)
De Gabriele, LC, Cooper, MG, Singh, S, Pitkin, J. “Intraoperative fiberoptic bronchoscopy during neonatal tracheo-oesophageal fistula ligation and oesophageal atresia repair”. Anaesthesia and Intensive Care. vol. 29. 2001. pp. 284-7. (TOF/EA and intraoperative bronchoscopy/tracheoscopy.)
Deanovic, D, Gerber, A, Dodge-Khatami, A. “Tracheoscopy assisted repair of tracheo-esophageal fistula (TARTEF): a 10-year experience”. Paediatr Anaesth. vol. 17. 2007. pp. 557-62.
Diaz, LK, Akpek, EA, Dinavahi, R, Andropoulos, DB. “Tracheoesophageal fistula and associated congenital heart disease: implications for anesthetic management and survival”. Paediatr Anaesth. vol. 15. 2005. pp. 862-9. (TOF/EA and congenital heart disease.)
Tercan, E, Sungun, MB, Boyaci, A, Kucukaydin, M. “One-lung ventilation of a preterm newborn during esophageal atresia and tracheoesophageal fistula repair”. Acta Anaesthesiologica Scandinavica. vol. 46. 2002. pp. 332-3. (One-lung ventilation (case report).)
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- What the Anesthesiologist Should Know before the Operative Procedure
- 1. What is the urgency of the surgery?
- What is the risk of delay in order to obtain additional preoperative information?
- 2. Preoperative evaluation
- 3. What are the implications of co-existing disease on perioperative care?
- b. Cardiovascular system
- c. Pulmonary
- d. Renal-GI:
- e. Neurologic:
- f. Endocrine:
- g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)
- 4. What are the patient's medications and how should they be managed in the perioperative period?
- h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?
- i. What should be recommended with regard to continuation of medications taken chronically?
- j. How To modify care for patients with known allergies -
- k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.
- l. Does the patient have any antibiotic allergies- [Tier 2- Common antibiotic allergies and alternative antibiotics]
- m. Does the patient have a history of allergy to anesthesia?
- 5. What laboratory tests should be obtained and has everything been reviewed?
- Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?
- 6. What is the author's preferred method of anesthesia technique and why?
- a. Neurologic:
- b. If the patient is intubated, are there any special criteria for extubation?
- c. Postoperative management