Anesthesia means the loss of sensation which can include a loss of consciousness or a loss of pain sensation or the simultaneous loss of pain sensation and consciousness. Anesthetics are drugs that with its effects on the nervous system cause anesthesia. Regional anesthesia is a technique in which the injection of a local anesthetic near a nerve or spinal cord inhibits pain, sensation and motor stimuli, which is a cause of the insensitivity to pain of a larger region of the body. The block I used in this study is an ultrasound and neurostimulator guided paravertebral block in breast surgery. Previous studies have shown high performance of external paravertebral blocks in breast surgery for anesthesia and analgesia. Since paravertebral space medially communicates with the epidural space, down over the intervertebral ligaments and up over the head and neck of ribs with the adjacent paravertebral space, I want to, by applying smaller volume of local anesthetic (7 ml per level) on three levels, avoid significant communication with the epidural space. Although many papers proved that the technique of giving the total volume of local anesthetic in paravertebral block divided on several levels is better than the technique of administering on one level only, it is still not clear what kind of solution of local anesthetics has better hemodynamic characteristics. The aim of this study was to determine which of the two solutions of local anesthetics in the paravertebral block has the most favorable effect in regards to the haemodynamic and analgesic impact. The study included patients with breast cancer, ages 18 to 80, ASA 1 and 2 status with respect to the including and excluding criteria. I conducted a randomized, prospective, double-blind study in 80 patients divided into two groups. In LLS- group I applied a solution of 0.5% levobupivacaine and 2% lidocaine, 7.0 ml per level (total of 7 ml 2% lidocaine + 14 ml 0.5% levobupivacaine), and in the second LS - group the solution of 0. 5% levobupivacaine also 7.0 ml per level (total 21 ml). The study was done with the application of ultrasound with in plane technique, neurostimulators and Vigileo / FloTrac system All patients were PVB monitored before and during the biopsy using ECG, non¬invasive measurement of blood pressure and saturation. After the successful performance, PVB patients were transferred to the operating room where the induction with propofol 1 % and vecuronium bromide was performed with the positioning of a laryngeal mask. All the patients were then ventilated by means of controlled mechanical ventilation with the maintenance of anesthesia and sedation by continuous infusion of Propofol 1% and Vecuronium bromide according to the target values of the BIS. After the induction, the mean arterial pressure and other hemodynamic parameters were measured through the arterial cannula using Vigileo / FloTrac system Regarding hemodynamic parameters, I measured primarily variations in stroke volume than mean arterial pressure, frequency, output, index cardiac output, systemic vascular resistance and the index of system vascular resistance. The measurements of the above parameters were done every 5 min during the first hour after the onset of paravertebral block and than every 15 minutes during the second hour, and if the surgery lasted more than two hours, measurements were carried out every 30 minutes. Postoperatively, I removed the arterial cannula in the recovery praćenje room and with all vital parameters satisfying, without present complications, the patients were referred to the ward accompanied with non-invasive hemodynamic praćenje til the cessation of the block. I monitored the patients' recovery on the ward during the first 24 hours, as well as the VAS scale every 3 hours by using the appropriate analgesic measures. I proved throught the study significantly higher values of variation in the stroke volume in the LLS group from the beginning of the measurement, and in all measuring times during the first hour. I found statistically significant differences in LLS - group in SW values - within and between the groups, particularly during the first 10 minutes of minimally invasive hemodynamic measurements. I proved the uniformity in SW values within the LS - group with no statistically significant differences during the measurements of hemodynamic parameters. I noted significantly higher compensation in the volume of intraoperative used crystalloids with the LLS group. With the conducted intraoperative crystalloid application, I reduced the application of vasoactive drugs. By applying the paravertebral block I achieved satisfactory postoperative analgesia and the mobilization in both groups of patients without the use of opioid analgesics in that period. According to the results and the proofs of this study, it can be concluded that the application of the solution of a local anesthetic with a longer time required for the participation in paravertebral block causes smaller hemodynamic changes with prolonged analgetic effect. This gives the solution advantages in the future implementation of the paravertebral block, especially in patients with ASA 3 and 4 status.