Postoperative pain continues to be untreated despite the application of multimodal analgesia, medication and new analgesic techniques. Traditional opioid pain treatment has many side effects, while invasive methods, such as epidural catheter, have high costs and difficulties during application.

Lidocaine is a local anesthetic and its administration with intravenous routes has analgesic, antihyperalgic and antiinflammatory action. It increases the motility of the intestine and has antiemetic properties. The advantage of this method is the low cost of the preparation and its easy application. The intravenous administration of lidocaine for postoperative analgesia is recently used and not sufficiently researched technique .

The purpose of this research is to investigate the analgesic effects of intravenous lidocaine in the perioperative and postoperative period, on various surgical interventions. In the perioperative period, its effect on the reduction of opiodic use will be evaluated, while during the postoperative period will be evaluate the degree of analgesia, the rate of reduction of additional analgesics, the impact on the clinical parameters and the patient's rehabilitation.

The research will be conducted at the Clinic of Gynecology and Obstetrics, the Surgery Clinic, the Urology Clinic, the Orthopedic Clinic, of Universitary Clinical Centre of Kosovo and the American Hospital in Pristina, Republic of Kosovo.

The study will be conducted during the period April 2018 - January 2020.

After obtaining a permit from the ethics committee, all patients to be investigated will be informed first through the information form for all the risks and advantages of this analgesic technique and from them will be consented to their participation in the research.

In the intervention group of the study will be included 520 patients of both genders and ages 18-65 years. Patients will undergo these surgical interventions: gynecological, abdominal, laparoscopical, urological and orthopedic interventions.

The intervention group includes two groups for each type of surgery:

Group I (n = 50); at induction of anesthesia will be given lidocaine 2mg / kg / i.v., bolus, and in perioperative and postoperative period will be given lidocaine 1.5mg / kg / h-1, continuously during surgery and 48 hours after surgery.

Group II (n = 50); at induction of anesthesia will be given lidocaine 2mg / kg / i.v., bolus, and ketamine 0.15mg / kg / , bolus, i.v .; lidocaine will continue during the operation and in the postoperative period with a dose of 1.5mg / kg / h-1, continuously, during the operation and 48 hours after the operation.

The control group (n = 30) will be given opioids during surgery, and opioids and nonsteroid antiinflammatory agents will be given 48 hours after surgery.

Inclusion Criteria:

• Age of both genders from 18 to 75 years
• ASA physiological status I-III
• Participation in abdominal, orthopedic, laparoscopical, gynecological and urological interventions.

Exclusion Criteria:

• Patient rejection
• History of chronic opioid intake
• History of renal, hepatic or psychiatric disorders
• Heart failure,
• Organ transplant history,
• Lidocaine allergy
• Family history of malignant hyperthermia

Individual participant data for primary and secondary outcome measures will be made available

Data will be available within 6 months of study completion

Requestors will be required to sign a Data Access Agreement and then these requests will be reviewed by an Independent Review Panel.