Effect of adding lidocaine to Patient Controlled Analgesia (PCA) with morphine on pain intensity after cesarean section with spinal anesthesia

Evaluate the effect of adding lidocaine to Patient Controlled Analgesia (PCA) with morphine on pain intensity after Cesarean section with spinal anesthesia

Two arm parallel group, double blind, randomised clinical trial of 80 patients between October 2018 to December 2018.

Before anesthesia, venous access in the forearm of the nondominant hand of patients are established. Thirty minutes before the procedure, 7ml /kg of crystalloid serum will given to these patients and then spinal anesthesia will be performed. Patients will be placed in the sitting position, and the spinal puncture will perform in the L3-L4 and L4-L5 level with mid-line approach. Then 10-15 mg of Bupivacaine 0.5% will be administered for the patient and the T4 sensory level will provided. After completion of anesthesia and patients' recovery, all patients will connected to a Patient-controlled analgesia (PCA) pump.

Preliminary selection of patients will be done according to inclusion and exclusion criteria.The inclusion criteria included candidates for non-emergency cesarean section with the spinal anesthesia. Patients with known sensitivity to lidocaine or bupivacaine will be excluded.

For patients in the intervention group, the PCA solution contain 50 ml of 2% lidocaine with 30 mg (3 ml) of morphine in 47 mL of normal saline (total volume 100 ml). In the control group, the PCA solution contain 30 mg of morphine (3 ml) in 97 ml of normal saline. The PCA will be set to administer a bolus dose of 0.5 mL with a lockout interval of 15 minutes and a background infusion rate of 2 mL/h.

The pain intensity of the patients in the two groups after surgery will be evaluated using the visual analogue scale (VAS) at 2, 4, 6, 12, 18 and 24 hours after surgery.

Before the start of the study, the list of subjects for 2 groups of the study will be determined randomly, using a computer-generated random list for 80 patients. Based on this list, envelopes in which the name of one of the treatment groups is written are prepared. These envelopes are placed in the operating room, and if patients meet the inclusion criteria, an envelope will be opened for each patient and their treatment group will be identified accordingly. This work will be done by an anesthetist technician.

This study will be double-blind, and the data analyser, collaborative nurses who will asses the outcomes of the study and patients are unaware of the patients' treatment groups.