Aetiology and control of cardiovascular reactions during trans-sphenoidal resection of pituitary microadenomas

Two groups of 12 patients were studied to determine the causes of hypertension during trans-sphenoidal resection of pituitary microadenomas. Two concentrations of lidocaine, 0.5 and 1.0 per cent with epinephrine 1/200,000, were used to infiltrate the nose and upper gingiva. Heart rate, electrocardiogram lead II and systolic and diastolic arterial blood pressures were monitored. Three stages were observed for changes in above parameters: nasal infiltration, nasal dissection and sellar exploration. Highly significant reductions in arterial blood pressure and pulse rate responses to infiltration and nasal dissection were achieved by increasing the lidocaine concentration used for infiltration from 0.5 to 1.0 per cent (p < 0.05). Our findings implicate reflex from nasal stimulation as the main cause of the adverse cardiovascular effects. Only minimal changes accompanied the progress of the intrasellar dissection in both groups.