Primary aim of this study is to evaluate affect of SPI guided antinociception on total intraoperative consumption of local aneshesics during analgesia. Secondary aims are defining time interval between LA administration and SPI value dropping under 50 and hemodynamy. Tertiary results are total mean local anesthesic consumption per hour, mean LA bolus number, total norepinephrine, ephedrine and atrophine consumption, mean intraoperative heart rate, mean arterial pressure, BIS and minimal alveolar concentration, percentage of intraoperative surgery time during which SPI>50, time passed until first post operative analgesia need, time needed to be discharged from PACU after operation (evaluated via Aldrte score) and post operative side effects (nausea, vomiting, sedatition and piruritis)

Inclusion Criteria:

• aged 18-60
• ASA I-III
• grade I unilateral PNL

Exclusion Criteria:

• BMI > 40 kg/m2
• drug or alcohol abuse history in the last 6 mounts
• chronic opoid usage or had chronic pain longer than 6 weeks
• peripheral and central neurological disorders
• preoperative hemodynamic disorders
• irregular sinus rhythm and pace makers
• diabetes, severe lung and major liver diseases with increasing biluribin
• use of anti-muscarinics, α2-adrenergic agonists, β1-adrenergic agonists, anti arrhythmic; who used chronic psychoactive drugs in last 90 days
• who are pregnant and breast feeding
• not willing to participate
• allergic or intolerant to any of the drugs in the study
• procedures that take less than 2 hours