Oxidative stress-associated hypertension in surgically induced brain injury patients: effects of β-blocker and angiotensin-converting enzyme inhibitor.
BACKGROUND
Postoperative hypertension is a common problem in patients undergoing surgical procedures, and the modification of this response could result in improved surgical outcome. Although it is recognized that the incidence of postoperative hypertension is higher in neurosurgical procedures, mechanisms behind this are not well understood. Oxidative stress is an important component of brain injury, and free radicals can influence blood pressure by a number of mechanisms. This study examined the effect of pretreatment with antihypertensive agents on postoperative hypertension in patients undergoing neurosurgery for supratentorial brain tumors and the role of oxidative stress in the process.


METHODS
Forty-nine consecutive patients who underwent surgery for supratentorial brain tumors were divided in to three groups (control, Tab. Glucose; atenolol; and lisinopril groups). Blood was drawn at three time points (1 d before the surgery, at the time of dura opening, and at the time of extubation). Hemodynamic parameters in all three groups and levels of malondialdehyde, protein carbonyl content, nitrate, and α-tocopherol in serum at various time points were analyzed.


RESULTS
The results showed that perioperative hemodynamic changes were highly associated with oxidative stress parameters in all the three groups. It was seen that atenolol and lisinopril significantly decreased levels of malondialdehyde, protein carbonyl content, and nitrate in the intraoperative period (P < 0.05), an effect which continued postoperatively.


CONCLUSIONS
The results demonstrate that pretreatment with β-receptor blocker (atenolol) or angiotensin-converting enzyme inhibitor (lisinopril) reduces postoperative hypertension in patients undergoing neurosurgery, and inhibition of oxidative stress may be a potential mechanism for this effect.