The purpose and the goal of this paper is to show whether the application of a combination of two local anesthetics, as opposed to the application of one local anesthetic at paravertebral block changes the hemodynamic variable. It is therefore a prospective randomized double- blind study, where we do a clinical trial in patients ASA(American Society of Anesthesiologists) 1 and 2 statuses between 18 and 80 years of age, using the ultrasound in plane technology.Upon arrival of patients in the unit for preparation procedures for anesthesia we set the ECG(electrocardiograph), noninvasive blood pressure, oxygen saturation, and arterial cannula in the radial artery After sterile washing of the dorsal surface, paravertebral space was identified with ultrasound using 8 Hz(hertz) linear transducer probe then needle position was confirmed with neurostimulation at the level of 2.0 - 5.0 mA(milliampere). When muscle contraction persisted at 0.4mA(milliampere), the anesthetic was applied in levels of Th 2, Th3, and Th 4 (7,0 milliliters per level). We applied the 0.5 % levobupivacaine and 2 % lidocaine, 7,0 milliliters of mixture per level in one group, while only 0.5 % levobupivacaine also 7,0 milliliters. by level in the second one. After that, the invasive hemodynamic monitoring was placed on patients and the induction with 1 % propofol 2-2.5 mg/kg.and Vecuronium 0,08 mg/kg. was performed with the application of supraglottic airway gel of appropriate size. The maintenance of anesthesia and sedation will be conducted with Propofol 1 % continuously ( 25-150 mcg / kg / min.)The measurements will be taken every 5 minutes during the first hour of the application of paravertebral block, then every 15 minutes during the second hour and if the operation takes more than two hours, the measurements are performed every 30 minutes. Postoperatively, invasive hemodynamic monitoring will be removed in post-anesthesia recovery room together with the arterial cannula and the patient will be sent to the hospital ward with non-invasive hemodynamic monitoring (blood pressure, pulse, saturation) until the termination of the blocks.Statistical methods, By comparing two target groups, we analysed the strength of the test with following assumptions: X2 difference test, the expected difference in variances in stroke volume between groups of 60%, α significance level of 0.05, and the minimum statistical test strength of 85%. The required total sample should include at least 80 patients, that is, 40 per group.Data will be presented in tables and graphs. Descriptive statistics of examined variables with appropriate measures of central tendency will be made. Smirnov -Kolmogorov test will assess the normality of data distribution. According to the received results, the appropriate parametric and / or nonparametric tests will be used. Comparisons of quantitative values between the two groups will be analyzed using the independent t-test or Mann-Whitney U test. Dependent values within each group will be analyzed using analysis of variance for repeated measures or Friedman test. Differences in categorical values will be analyzed by X2 test. The appropriate regression model will be made in order to predict the variability of stroke volume in which the dependent variable will be a variation of the stroke volume, while relevant clinical values will be taken as predictor variables. All P values smaller than 0.05 will be considered significant.

This research is to present the main results - the existence of the significant change in Stroke Volume Variation (SVV) between groups using invasive hemodynamic monitoring, the changes of Stroke Volume Variation(SVV) depending on the time from the application within groups, differences in volume compensation of crystalloids and colloids and the need for the application of vasoactive drugs. Furthermore, as a secondary results we will present the time to maximal block development, the duration of post operative analgesia, patient satisfaction and time needed for the full recovery from the block.

Inclusion Criteria:

• ASA one and two status
• regular heart rhythm
• weight between 50 and 95 pounds

Exclusion Criteria:

• patient refusal
• coagulation disorder
• allergy to local anesthetics
• arrhythmias with or without valvular disease
• hypertension
• weight less than 50 pounds or more than 95 pounds