Management of airway in intratracheal tumour surgery.

Abstract

Sir, Tracheal tumours occur infrequently accounting for <1% of all neoplasms.[1] They usually become symptomatic when they start obstructing more than 75% of the tracheal lumen.[2] Management of airway in tracheal tumours is challenging to the anaesthesiologist because a patent airway has to be established and maintained throughout the surgery while ensuring adequate surgical exposure free of anaesthetic equipment, blood and debris. A 57-year-old male patient was admitted with complaints of shortness of breath on mild exertion and on lying supine. On examination he was dyspnoeic using his accessory muscles of respiration. On auscultation his lungs were clear. He was maintaining an oxygen saturation of 100% on room air in the sitting position that dropped to 95% on lying down. His arterial blood gas (ABG) analysis and chest X-ray were normal. A multiple detector computed tomography scan of the chest showed a lobulated mass (2.6 cm × 1.6 cm × 2.5 cm), 4.5 cm from the vocal cords. Fibreoptic bronchoscopy (FOB) was performed under local anaesthesia which showed a mass distal to the cords, bleeding on touch. A bronchoalveolar lavage was done, and the washings were sent for cytology that suggested a dysplastic squamous cell carcinoma. Surgical resection of the trachea was planned, with induction and maintenance of general anaesthesia via a normothermic femoro-femoral cardiopulmonary bypass (CPB). Monitoring included electrocardiogram, pulse oximetry, capnography, thermometry, ABG, activated clotting time and continuous invasive blood pressure monitoring. Lumbar puncture was performed at L3-L4 interspace with a 25 gauge spinal needle and 2 ml of 0.5% hyperbaric bupivacaine was administered. Dexmedetomidine infusion was started at 30 μg/h. After 1 h of spinal anaesthesia, the patient was fully heparinised and a femoro-femoral CPB was established. Thiopentone 200 mg, fentanyl 100 μg and rocuronium 60 mg was added to the circuit. After a median sternotomy, through a flexible FOB the tumour location was determined, two tracheal rings were removed along with the tumour and an end-to-end anastomosis of the trachea was performed. A size 8 endotracheal tube was then passed using the FOB. The anastomosis was checked for any leak, sealed with N-butyl cyanoacrylate and after confirmation of absence of leak, ventilation was continued through it. The patient was then weaned off CPB. A guardian stitch was placed between the chin and anterior chest. The patient was haemodynamically stable during the entire procedure. Trachea was extubated after completion of surgery and patient was shifted to the Intensive Care Unit. The anaesthetic technique employed for tumour resection depends on size, location, extent of luminal occlusion and whether it's a bronchoscopic procedure or a surgical resection. Widely used methods are high-frequency jet ventilation, rigid bronchoscopy, distal tracheal intubation, tracheostomy under local anaesthesia, one lung ventilation, CPB and extracorporeal membranous oxygenation.[3] Rigid or flexible bronchoscopy guided tumour resection using Neodymium-doped Yttrium Aluminium Garnet, cryotherapy, and KTP laser are quite popular but are used for pedunculated, benign tracheobronchial lesions which have a low recurrence rate.[4,5,6] Laser resection does not guarantee complete tumour removal and is used as a palliative procedure, and for emergency airway dilatation. High-frequency jet ventilation via a narrow bore catheter used for oxygenation increases the movement of the mass, dislodges small tumour fragments distally and can cause pneumothorax. Most importantly, under spontaneous ventilation, if rigid bronchoscopy does not maintain airway patency requiring a tracheostomy, then it can only be done after a sternotomy before which the patient may develop severe hypoxia and hypercarbia leading to adverse cardiac outcomes. There are several risk factors associated with CPB mainly due to anticoagulation associated bleeding, air embolism, pulmonary haemorrhage, etc. However, in our patient, the distal location of a malignant, wide based tumour which required resection of two tracheal rings and not just bronchoscopic tumour resection made CPB the technique of choice for ensuring adequate oxygenation and ventilation. Through this report, we highlight the paramount importance of CPB as an effective alternative anaesthetic technique during tracheal resection of malignant tracheal tumours.