CHAPTER 36: Airway Management of a Patient with a History of Oral and Cervical Radiation Therapy

CASE PRESENTATION

A 68-year-old male was found on CT to have a right lung nodule and paratracheal lymphadenopathy. He was then scheduled for diagnostic bronchoscopy and mediastinoscopy.

Twenty years ago, he was diagnosed with carcinoma of the right submandibular gland, and underwent excision of the gland, right radical neck dissection, and a course of radiotherapy. He quit smoking several years ago and has had hypertension for about 5 years. He has had a nonproductive cough for several months. His only medication is metoprolol.

On examination, he is in no distress at rest. His vital signs are: blood pressure 140/90, heart rate 70, and respiratory rate 18. Oxygen saturation on room air is 96%. His weight is 94 kg and he is 170 cm tall. Auscultation of the chest reveals decreased breath sounds bilaterally but no rales or rhonchi, and normal heart sounds. No carotid bruits are evident.

Airway examination reveals a Mallampati IV classification. Mouth opening is 2.5 cm and mandibular protrusion is less than 1 cm. Full upper dentition is present but the mandible is edentulous. The thyromental distance is normal. Cervical spine extension is decreased. Palpation of the submandibular tissues reveals a woody, indurated consistency. On inspection, telangiectasia and pallor of the submandibular skin are noted. The right neck has the typical appearance of a previous neck dissection. The mucosa of the tongue appears dry.

Laboratory data reveal normal electrolytes and a hemoglobin of 140 g·L⁻¹. EKG reveals nonspecific ST and T changes.

ANESTHETIC CONSIDERATIONS

Is This Patient Fit for Anesthesia?

The patient has hypertension which is adequately controlled for his surgical procedure. Carcinoma of the lung is suspected on diagnostic imaging. He does not require further medical optimization.

What Anesthetic Technique Is Required?

General anesthesia with endotracheal intubation is required for a brief but stimulating surgical procedure.

What Anatomic and Pathophysiologic Changes Occur Following Radiotherapy to the Structures of the Oral Cavity and Neck?

Radiotherapy inflicts a radiochemical injury to both normal and malignant cells.¹ The damage is related to the total radiation dose and the method of radiotherapy delivery. In order to achieve adequate tumor control, damage to normal tissues is inevitable.^1-3 Radiation also activates various cellular signaling pathways that lead to activation of proinflammatory and profibrotic cytokines, vascular injury, and activation of the coagulation cascade.⁴ Early (acute) tissue toxicities from radiotherapy are arbitrarily considered to occur within 90 days of the commencement of treatment, and late effects beyond 90 days of treatment.^2,5 Early side effects are observed shortly after a course of radiotherapy, whereas late effects are manifest after a latent period and may not be evident until years following the radiotherapy.^2,...