The incidence of vasovagal reflex activity during radical neck dissection.

Pressure receptors exist within the walls of the carotid bulb which are responsible for maintaining the balance between blood volume, vascular tone, and cardiac output. When these receptors are manipulated during neck surgery the result may be bradycardia, hypotension or cardiac arrythmia. Such events occur sporatically during head and neck surgery and occasionally may prove fatal. While many surgeons advocate anesthetizing the carotid bulb prophylactically, this practice is not universally accepted. A retrospective appraisal of 76 radical neck dissections demonstrated an incidence of clear cut vasovagal reflex activity of 10%. Thirty-one radical neck procedures were then randomized into treatment and control groups in a prospective fashion. The treatment group (12 patients) had 5 cc. of 2% lidocaine applied topically to the carotid bifurcation. Nineteen controls had normal saline applied to the same site. The incidence of vasovagal reflexes in the control group was 10% and 16% in the treatment group. The similarity of these treatment groups is highly significant. It is concluded that topical 2% lidocaine is not an adequate prophylaxis for vasovagal reflexes during radical neck dissection.