The rupture of the extracranial carotid arteries or their major branches. It is an uncommon but devastating complication of head and neck cancer. Predisposing factors include: prior radiation therapy, extensive surgery, wound breakdown, local infection, tumor recurrence, and pharyngocutaneous fistulae.
Carotid blowout syndrome (CBS) ranges from asymptomatic exposure of a carotid artery to acute hemorrhage. CBS is described as either threatened, impending (transoral hemorrhage or “sentinel" bleeding), or acute.
The gold standard for diagnosing CBS is angiography. It is the preferred diagnostic modality because of its potential therapeutic capabilities (endovascular stenting, for instance, can occur during the same procedure). Computed tomographic and magnetic resonance angiography can also be helpful in identifying and characterizing threatened lesions.

Treatment
Prior to the era of endovascular intervention, treatment for CBS was surgical ligation of the bleeding artery causing high morbidity (stroke) and mortality. A newer technique, endovascular stenting, is associated with far fewer immediate complications.
- Threatened CBS. Early endovascular stenting is indicated, before frank hemorrhage occurs.
- Impending/acute CBS. Stabilization allows for accurate diagnostic angiography and subsequent endovascular treatment. If interventional radiology therapies are unavailable or unsuccessful, emergent surgical intervention is indicated.

Approach to the patient at the end of life.
Patients near the end of life may want medical care solely focused on symptom alleviation without life prolongation.
Preparation of patients, professionals, and family caregivers is important to minimize panic and distress from copious amounts of blood, and to ensure patient comfort during bleeding.

An emergency care plan should include the following elements:
- Ready availability of dark-colored linens/towels to cover and absorb blood (less distressing than seeing bright red blood on white linens); gloves, face/eye protection (in case of brisk arterial spraying), and other universal precautions.
- Suctioning equipment for clearing the mouth or tracheostomy of blood is desirable, if available.
- Symptom drugs and explicit instructions on how to use them.
For brisk bleeding, rapid patient sedation is indicated to palliate fear, dyspnea, and suffocation. Drug and route choice will depend on patient location (home vs. hospital vs. inpatient hospice) and intravenous access, but when available the approach is similar to providing continuous, deep sedation — expert opinion recommends doses in the range of 5-10 mg of midazolam subcutaneously initially.
Opioids for pain and dyspnea are also indicated.

For massive hemorrhages, there may not even be time to administer comfort meds prior to patients losing consciousness.
A plan should include instructions on whom to call, and whether and where to transport the patient, if at home.

See reference for more information.

Adapted from Kozin E et al. Carotid blowout Management. Palliative Care Network of Wisconsin. Fast facts and concepts #257. Internet. Accessed on January 15, 2018.