To the Editor:—
The Harmonic Scalpel® (Ethicon, Somerville, NJ) and laser are precise cutting and coagulating surgical devices. These devices are widely used worldwide for endoscopic and open surgical procedures. We describe our experience with the Harmonic Scalpel® during the anesthetic management of head and neck oncosurgery.
A 58-yr-old male with postradiation recurrence of tongue and soft palate carcinoma was scheduled for wide excision and functional neck dissection with the Harmonic Scalpel® under general anesthesia. After induction of general anesthetic, direct laryngoscopy was performed and an 8 mm cuffed endotracheal tube (ETT) was introduced nasotracheally under vision. Maintenance of anesthetic was achieved with opioids, muscle relaxants, and positive pressure ventilation with 66% nitrous oxide, 34% oxygen, and 0.8% halothane delivered by anesthesia ventilator. The patient remained stable and was closely monitored while the surgeons proceeded with dissection using the Harmonic Scalpel®. While the soft palate lesion was being dissected, the ventilator suddenly emitted the low airway pressure alarm and stopped functioning. The surgical team also noticed bubbling of blood inside the oral cavity. Damage to the ETT was suspected and the head end of the operating table was immediately lowered to prevent aspiration of blood that had pooled in the oropharynx. The fraction of inspired oxygen was increased to 60% and manual ventilation was attempted after thorough suctioning of the oral cavity. However, this was unsuccessful due to the leak (fig. 1), and a fresh ETT of the same size was introduced with the aid of a tube exchanger. The patient was reversed at the end of surgery and the ETT was retained overnight. The postoperative period was uneventful.
The blade of the Harmonic Scalpel® vibrates at 55,000 Hz. It cuts and coagulates tissue at temperatures much lower than either lasers or traditional electrocautery. As a result, the risk of airway fires should be reduced. However, as shown here, it is clear that the Harmonic Scalpel®—like a laser—can cause accidental damage to the ETT when used in the pharynx.
The existing literature abounds with techniques to protect the airway and the ETT from lasers and to manage fires when they occur.1–6Substitution of the Harmonic Scalpel® can eliminate the risk of fire (and does not dictate the use of lower concentrations of oxygen), but ETT damage may still occur.
* Regional Cancer Centre, Trivandrum, Kerala, India. firstname.lastname@example.org