Anaesthesia management of 'tubeless' tracheal resection.

Sir,

Ventilation of the lungs when the airway is shared with the surgeons is the challenge for anaesthesiologists during tracheal surgeries. We report our experience with a ‘tubeless’ approach during tracheal resection.

A 19-year-old, 50 kg male, presenting with a non-obstructive adenoid cystic carcinoma of the posterior tracheal wall, was planned tracheal resection with end-to-end anastomosis. In the operation theatre, invasive arterial monitoring was instituted in addition to standard anaesthesia monitors. Anaesthesia was induced with propofol, fentanyl and controlled ventilation using oxygen-air-isoflurane through a small-sized endotracheal tube (ET). LASER guided delineation of posterior mucosal cuts was performed using a micro-laryngoscope. Following the frozen section report, surgeons proceeded to resect the trachea. The ET was replaced with a size 4 ProSeal laryngeal mask airway (PLMA). Bronchoscopy through PLMA confirmed an unobstructed view of vocal cords. Controlled ventilation was continued through PLMA till 30 min before the expected time of tracheal cut. Then, an infusion of propofol (at 100 mg/kg/min) replaced the inhalational anaesthetics. Boluses of neuromuscular blockers were avoided. When the trachea was incised, the patient had resumed spontaneous breathing. Two millilitres of 4% lignocaine were instilled on the tracheal mucosa. Oxygen was delivered through the PLMA at 5 litres/minute till the time the two cut ends of the trachea were in approximation. Later, the patient breathed room air through the cut lumen of the distal trachea at 16-20 breaths per minute. Oxygen saturation was maintained between 98 and 100%, and the partial pressure of carbon dioxide in the blood remained between 50 and 55 mmHg. The surgeons applied intermittent suction to prevent aspiration of blood clots into the distal airways. Three tracheal rings along with the right lobe of the thyroid were resected. Avoiding muscle relaxants enabled the surgeons to perform nerve monitoring, for which electrodes were inserted into the thyroid cartilage. End to end anastomosis of tracheal ends was performed without any interruption [Figure 1]. The total duration of the procedure was 4 hours. At the end of the surgery, no neuromuscular reversal was required, PLMA was removed and the further recovery was uneventful.

Figure 1

Various steps during tubeless surgery. (a) two cut ends of the trachea; also note the sensor inserted in the thyroid cartilage for nerve monitoring. (b) closure of posterior tracheal wall. (c) closure of the anterior tracheal wall. (d) at the end of the surgery, prior to removal of ProSeal laryngeal mask airway

The traditional ‘cross-field ventilation’ involves repeated removal and insertion of ET through the surgical field in synchrony with surgical steps and oxygen saturation. It has a few disadvantages like the repeated interruption of surgery, hypercarbia and hypoxia (during apnoea phase), barotrauma and volutrauma (during ventilation phase) and contamination of the surgical field. Other methods like automated jet ventilation require a specialised ventilator and a narrow calibre, sturdy tube. It also causes exposure to dry gases, a rise in airway pressure, and hypercarbia when operated at a very high frequency. The apnoeic oxygenation technique works by delivering high flows (40-70 litres per minute) of humidified oxygen using a narrow tube across the surgical field. Although it maintains oxygenation, it carries the risk of hypercarbia on prolonged apnoea.[12]

The approach of spontaneous breathing during tracheal surgeries has been reported in recent times.[345] The ‘tubeless’ approach avoids muscle relaxants, laryngoscopy and lower airway instrumentation, facilitates nerve monitoring during the surgery and maintains spontaneous breathing which is lung protective. The cough reflex is suppressed by topical anaesthesia of the tracheal mucosa and intra-operative vagal block. Non-interruption of surgical steps shortens the duration of surgery.

The ‘tubeless’ approach mandates some precautions. Patients with restrictive lung disease, obesity and infected lungs may become hypoxaemic while breathing room air. Oxygen delivery into the surgical field interferes with the use of cautery. Aspiration of blood clots may obstruct the lower airway. Light plane of anaesthesia may result in laryngospasm during the surgery. Too deep plane of anaesthesia induces respiratory depression and hypercarbia. In the case of obstructive tracheal lesions, high peak airway pressures may preclude the use of LMA. Cross-field ventilation should be reserved as a backup plan in case of hypoxaemia.

Thus, the ‘tubeless’ approach is a safe and feasible option for anaesthesiologists during tracheal resection in carefully selected patients.

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Conflicts of interest

There are no conflicts of interest.