Bypassing trachea-oesophageal fistula during endotracheal intubation for surgical correction: Time to rethink!

Sir, Tracheo-oesophageal fistula (TOF) results from a congenital fistulous communication between the oesophagus and trachea or one of its main branches. An important goal of ventilation in a TOF patient is to avoid gastric distension prior to surgical ligation of the fistula. Conventionally, following deliberate endobronchial intubation, the tip of the endotracheal tube (ETT) is withdrawn into the trachea till breath sounds are heard on the left side. This strategy is believed to be efficacious as the posterior wall of the ETT is thought to occlude the fistula. However, such an approach can result in the ETT lying just at carina and may lead to carinal stimulation and increased airway resistance intraoperatively. Also, when a patient is turned from supine to lateral position, ETT movement may result in mainstem bronchial intubation or it may slip into a large fistula resulting in ventilatory inadequacy.[1] Another concern in using the uncuffed ETTs for this purpose is that the external diameter of these ETTs is much smaller than that of the neonatal trachea and, therefore, these uncuffed tubes are unlikely to bypass the fistula in cases with high pulmonary inflation pressures. We faced such difficulty during the anaesthetic management of a 2-day-old neonate with a TOF and bilateral pneumonitis. Following intubation, using the technique of deliberate endobronchial intubation followed by its withdrawal till the breath sounds appear into the left lung on auscultation, the child was positioned in lateral decubitus position for surgery. Pressure controlled mode of ventilation was initiated. Soon after positioning, the peak airway pressures rose very high (>40 mmHg) despite adequate muscle relaxation and delivered tidal volumes fell to 5–7 ml from 25 ml. The ETCO2waveform showed an obvious slant in the up-stroke and loss of the expiratory plateau. On auscultation, breath sounds were diminished and conducted sounds were heard bilaterally. The patient was removed from mechanical ventilation and manually ventilated using 100% oxygen. The bag felt tight and ventilation required high pressures. Anaesthesia was deepened and salbutamol puffs were administered without any improvement. However, oxygen saturation remained >95% and we decided to do fiberoptic bronchoscopy to look for the cause. On bronchoscopy, the ETT was seen to be abutting the carina. Slight withdrawal of the ETT led to immediate improvement in the clinical parameters. Since then, we have started to intubate the TOF cases using fibreoptic bronchoscopy (FOB)-guided bypassing of the fistula (wherever feasible) by first estimating the distance of the fistula from the carina. Our preliminary experience of bronchoscopy in 11 TOF cases, it was revealed that 1 fistula was left endobronchial in origin, 3 were carinal in location and 2 were within 1 cm of carina and only 5 were more than 1 cm distance from carina. Microcuff ETT with a more distal location of cuff (5 mm from the tip in 3.0-mm ID ETT) may be advantageous in cases with distal fistula.[2] However, microcuff ETTs are expensive and not readily available. Moreover, the smallest available microcuff tube is 3-mm ID which fits neonates >3 kg as per manufacturer's specifications. This will be an important limitation in our patient population where babies are often less than 3 kg. Use of Fogarty catheter has been described to occlude fistula in such cases but is technically difficult to place and has its own disadvantages. Alabbad et al. had reported demise of a full-term neonate due to intubation of large carinal fistula when the child was positioned lateral for surgery.[1] They had also advocated bronchoscopy to assess size and location of TOF. Rigid/fibreoptic bronchoscopy provides multifold advantages in TOF cases: ruling out more than one fistula, concomitant airway anomalies and establishing the fistula position in relation to carina in order to decide on the airway management strategy. In a study on 113 neonates with TOF, Holzki et al. found that in 22% of cases, the fistula was within 1 cm of carina and 11% of cases, it was bronchial in origin.[3] Use of routine preoperative bronchoscopy in TOF cases has been found to alter airway and surgical management in many patients.[45] In view of above concerns, we question the practise of blind attempts at bypassing the TOF. Rather, FOB-guided ETT placement would be safer and more effective, especially in cases with clinical suspicion of a large fistula. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

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