Case presentation

Patient profile

A 22-year-old male, weighing 68 kg, was diagnosed with skeletal Class III malocclusion and planned for elective orthognathic surgery consisting of Le Fort I osteotomy with maxillary advancement, bilateral sagittal split osteotomy for mandibular setback, and advancement genioplasty. The patient had no significant medical comorbidities and was classified as American Society of Anesthesiologists physical status I. Preanesthetic evaluation revealed normal airway parameters with Mallampati class I, adequate mouth opening, and normal neck mobility. Routine investigations were within normal limits. Written informed consent for surgery and publication of this case report was obtained from the patient. Notably, this reassuring airway assessment did not preclude the subsequent complication, which arose from within the surgical field rather than from any anatomical airway difficulty.

Anesthetic management

The patient was premedicated and induced under standard monitoring, including electrocardiography, non-invasive blood pressure, pulse oximetry, and capnography. Following intravenous induction and neuromuscular blockade, oral intubation was performed with a cuffed 7.0 mm internal-diameter flexometallic (reinforced) ETT, which was subsequently converted to submental intubation to facilitate surgical access (Figure 1). Submental conversion was carried out using the standard Hernández Altemir technique: a short paramedian submental incision was made, blunt dissection was carried through the floor of the mouth into the oral cavity, and the temporarily disconnected tube, together with its pilot balloon, was delivered through the submental tunnel and reconnected [3,5]. Submental rather than nasotracheal intubation was selected on surgical grounds rather than for any airway difficulty: the planned Le Fort I osteotomy and the need for repeated, unobstructed intraoperative assessment of the dental occlusion make a nasotracheal tube liable to obscure the field and to be displaced or damaged during maxillary manipulation, whereas the patient's Mallampati class I airway posed no barrier to conventional intubation.

Figure 1: Clinical photograph demonstrating submental intubation with the endotracheal tube

Correct placement was confirmed by bilateral chest auscultation and continuous capnography. The tube was secured with the submental segment retracted clear of, and positioned away from, the mandibular symphysis, and the oral cavity was packed. Anesthesia was maintained with inhalational agents in an oxygen-air mixture and intermittent doses of muscle relaxant.

Intraoperative event

The Le Fort I advancement and bilateral sagittal split osteotomy setback were completed uneventfully. During the genioplasty phase, while performing the horizontal osteotomy in the mandibular symphysis region using a powered oscillating saw (Figure 2), the anesthesiologist noted a sudden decrease in delivered tidal volume, an audible air leak, and a reduction in peak airway pressure. The capnography waveform became irregular, and the ventilator alarm indicated a circuit leak. Bubbling of air mixed with blood was observed at the genioplasty osteotomy site (Figure 3), raising suspicion of ETT damage.

Figure 2: Illustration of the relationship between the endotracheal tube and the surgical fieldCreated by the authors using Adobe Illustrator

Figure 3: Genioplasty osteotomy site

Manual ventilation revealed increasing difficulty in maintaining adequate ventilation, with reduced chest rise and falling oxygen saturation.

Management

Surgery was immediately halted, and the surgical field was packed. The anesthesiology team switched to 100 percent oxygen and attempted to maintain ventilation manually. Direct inspection revealed partial transection of the ETT in the submental portion, likely caused by the osteotomy instrument.

An emergency ETT exchange was performed under direct laryngoscopy with surgical assistance for tissue retraction. The damaged tube was carefully removed and replaced with a new cuffed ETT using a bougie as an airway guide (Figure 4).

Figure 4: Partially transected endotracheal tube (marked within a red circle)

Tube placement was reconfirmed by capnography and auscultation. Oxygen saturation returned to normal, ventilation parameters stabilized, and surgery was resumed after ensuring hemostasis and airway security. The genioplasty was completed cautiously without further complications (Figure 5).

Figure 5: Fixation of the genioplasty segment