Cardiovascular responses to scalp infiltration with different concentrations of epinephrine with or without lidocaine during craniotomy

Intraoperative blood pressure changes alter cerebral blood flow in neurosurgical patients with impaired autoregulation. Infiltration of the scalp before craniotomy may cause hemodynamic changes that depend on the composition of the solution used. We investigated cardiovascular responses to infiltration of the scalp with five different combinations of epinephrine and lidocaine in 112 patients: Group A,lidocaine 0.5%; Group B, lidocaine 0.5% with epinephrine 1:200,000; Group C, lidocaine 0.5% with epinephrine 1:100,000; Group D, normal saline with epinephrine 1:200,000; and Group E, normal saline with epinephrine 1:100,000. Episodes of tachycardia occurred more frequently in group E (P = 0.03). Plain lidocaine did not cause any significant change in blood pressure. The incidence of systolic, diastolic, and mean arterial hypertension was significantly increased in group E (P < 0.01). Episodes of diastolic hypertension occurred more frequently in Group D (P < 0.01). A biphasic diastolic and mean arterial hypotension(around Minute 2 and Minutes 9-15) occurred in Groups C and B (P <less than> 0.001). In conclusion, epinephrine 1:100,000 causes significant tachycardia. Epinephrine in concentrations of 1:100,000 and 1:200,000 causes significant hypertension. The combination of lidocaine and epinephrine attenuates the hypertension but results in a biphasic hypotensive response.