Epinephrine; Errors; Concentration; Endonasal surgery

This paper presents two cases of using erroneous concentrations of epinephrine during endonasal surgery. The two patients discussed were part of a larger study aimed at monitoring the absorption of epinephrine upon injection into the nasal mucosa. During this study, we observed major cardiovascular reactions in two consecutive patients--ventricular tachycardia with ventricular extrasystole and a significant rise in systolic and diastolic blood pressure and pulse rate. The authors have analysed the steps leading to the erroneous applications and recommend safety precautions for the prevention of errors in the concentration levels of epinephrine. Epinephrine injections in concentrations of 1:10,000, followed by analyses of epinephrine levels in venous blood, have not yet been described in available literature.