Does therapy with beta-blockers affect changes in blood pressure during the performance of spinal anesthesia?: Beta-blockers and regional anesthesia

Abstract

Introduction: Spinal anesthesia is one of the oldest, most useful and most commonly used techniques of regional anesthesia. The injection of local anesthetics into the subarachnoidal space creates a transient interruption of nerve impulses in the spinal nerve roots and paralysis of autonomic, sensitive and motor nerve endings. Sympathic blockade caused by spinal anesthesia leads to haemodynamic changes. Hypotension and bradycardia are the most common cardiovascular effects seen in sympathetic denervation. The goal of the work: Determine the effects of chronic therapy with beta-blockers on changes in arterial blood pressure during spinal anesthesia, since their effects are similar, and see the importance of hemodynamic monitoring (measurement of arterial pressure) in performing spinal anesthesia in this group of patients. Material and methods: After the approval by the Ethics Board of the University Clinical Center Banja Luka, a prospective, case-control study was conducted, which lasted from 01.06.2013. until 31.05.2016. at the surgical clinics of this institution. The study included 70 patients divided into two groups, aged 35-65 years. Group N1, a working group, consisted of 35 patients who, due to essential hypertension, used a beta-blocker, metoprolol, in chronic therapy. The second group was the control group, N2, and it consisted of 35 patients of the same age, ASA I status. Patients were subjected to spinal anesthesia for 'bloodless' inguinal hernia repair, bladder tumor operation, prostatic surgery, the urethra and lower extremities operations. Pregnant women, as well as patients with diabetes, renal, hepatic and heart diseases were not included in the work. Results: The results show that a decrease in arterial blood pressure (systolic, diastolic and mean) in the group of patients under beta-blocker therapy is significantly higher after performing spinal anesthesia. In the control group, systolic pressure decreased by about 11% after performing spinal anesthesia, while in the working group it decreased by 20%. Diastolic pressure after performing spinal anesthesia in the control group fell by 11.33%, which was a statistically significant decline. In the workgroup, this drop (from DP1 to DP2) was 20.4%.The mean arterial pressure after spinal anesthesia fell in the control group by 4%, while in the working group we recorded a decrease of MAP1-MAP2 of 20%. Conclusion: Patients on perioperative therapy with beta-blockers that underwent spinal anesthesia are hemodynamically unstable and require more efficient hemodynamic perioperative monitoring and intensive supervision.

Keywords

• spinal anesthesia
• beta-blockers
• arterial blood pressure