Hemodynamic changes after interscalene brachial plexus block depending on its side

Abstract

Background and Goal of Study: Interscalene brachial plexus block (ISB) is a first choice method performing shoulder surgery or diagnostic procedures around the world. Despite this common procedure there are still many undesirable events concerning hemodynamic changes. Exact causes are not yet fully determined. The goal of our study is to find how hemodynamics of patient is af fected by ISB depending on its side. Materials and methods: We investigated 78 patients, who needed shoulder surgery. All subjects were in sinus rhythm, and no abnormalities were detected with medical history and physical examination. Patient exclusion criteria: refused consent of enrollment in the investigation; coexisting diseases that were likely to impact changes in hemodynamics during the surgery. Af ter obtaining the approval from the Ethics Committee the patients were included randomly into 2 groups depending on operating side. Two equal groups of 39 patients underwent one side ISB. All patients received 0.5% 20 ml bupivacaine and 2% 20 ml lidocaine Ultrasound-Guided ISB. Hemodynamic changes were registered with impedance cardiography test and standard patient monitoring in various periods of operation for the first hour. Results and discussion: The patient population included both sexes, median age was 42,3 years with the ASA physical status I and II, weight from 50 to 98 kg and height between 155 and 192 cm. We found statistically significant difference between lef t and right side block. Lef t side ISB caused lower cardiac index af ter 10, 20 and 40 min. Systemic vascular resistance index was lower in every stage af ter 10 min. Mean blood pressure was lower af ter positioning the patients, 20, 30 and 60 min. Drop in heart rate was observed af ter 20 and 40 min. in lef t side block group. Acceleration index was higher in lef t side group af ter 10, 20 and 30 min. There was no statistically significant differences concerning systolic index and cardiac output. ISB has a dif feren