Pre-anaesthetic check-up:

Study will be conducted after approval by the Institutional Ethics Committee and will be registered with clinical trials registry India (CTRI). Patients fulfilling the inclusion criteria will be recruited for the study. A careful pre-anaesthetic check-up including detailed history, physical examination, baseline investigations as per clinical requirements will be performed. A written informed consent will be obtained for anaesthesia, surgery and participation in the study.

Quality assurance mechanism:

Recruitment of the subjects, sampling strategy, methods of data collection and subsequent data handling will be predefined. All the procedures to be performed will be standardized and training will be provided to reduce variability in outcome measurement.

Trial monitoring mechanism:

The rights and well-being of subjects will be protected. The reported trial data will be accurate, complete and verifiable from source document. The conduct of the trial will be in compliance with the protocol, good clinical practice and with the applicable regulatory requirements. Trial recruitment and outcome measurement process will be kept uniform throughout the study.

Safety issues:

Every Serious Adverse Event (SAE) that maybe related to the studied treatment or not, expected or unexpected will be reported within 24 hours by the investigator to the ethical committee.

Treatment fidelity:

 The treatment in this study is conducted consistently and reliably. The outcome of treatment research will not affect patient care or the quality of care that patient receives.

Randomization:

An investigator with no further involvement in the study will generate a list of random numbers between 1-70 by using computer randomization into two equal groups. The unique randomization code will be allocated to each patient and used to randomize consenting patients equally with no restrictions or bias to either of the two study groups:  Group S and Group N. A specific code will be allotted to the patient.

Group S: Patients who will receive USG guided SAP Block which will be followed by general anaesthesia

Group N: Patients who will receive only general anaesthesia

Allocation concealment and implementation of allocation:

The results of the allocation will be concealed in sequentially numbered sealed opaque envelopes mentioning the code and the group number. These envelopes with results of allocation will not be seen by the research coordinator prior to sealing and will only be kept by the coordinator after sealing. On the day of surgery, the coordinator will hand over an envelope to the senior anaesthesiologist supervising the OT.

Observation and data collection will be done by the investigator, who will be blinded to allotment and intraoperative management given. Person analysing the data will also be blinded.

Premedication:

Patients will be premedicated with alprazolam 0.25 mg PO on night before surgery. On the morning of surgery after confirming adequate fasting patients will be shifted to operating room. Routine monitors i.e., electrocardiography, pulse oximetry and non-invasive blood pressure will be attached and base line readings noted. An intravenous line will be secured and IV fluid will be started.

Performing the block:

In group S, serratus Anterior plane block will be performed in supine position with arm abducted to 90 degrees with ultrasound guidance using 6-13 MHz linear probe and a 22G 80-mm regional block needle, by a trained anaesthesiologist. The patient will be in the supine position. The USG probe will be placed in the transverse plane, over either eighth or ninth rib. Latissimus Dorsi (LD) and Serratus Anterior could be identified here. The thoracodorsal artery will identified at the onset of scanning and care will be taken to avoid it, while USG needle will be inserted in plane from posteromedial to anterolateral direction, toward posterior axillary line till it has reached the plane between LD and SA. Placement of the needle tip will be confirmed by hydrodissection. After confirming negative aspiration, 20 mL of 0.25% bupivacaine will be injected. The same will be given on the other side. After administration of block, patients in group S will be given general anaesthesia. In group N, patients will receive only general anaesthesia.

Intraoperative management:

In both groups intravenous fentanyl 2μg/kg will be given. Induction of Anaesthesia will be done using propofol 2 mg/kg along with O2, N2O and sevoflurane. Inj. Rocuronium 0.8 mg/kg will be used to facilitate endotracheal intubation and anaesthesia will be maintained with O2, N2O, sevoflurane and rocuronium. Every hourly, additional fentanyl 0.5 mcg kg IV was given if there was a 15% increase in hemodynamic parameters (heart rate and mean BP) from baseline. Inj Ondansetron 0.1mg/kg will be given after induction. A BIS of 40-60 and EtCO2 of 35-45 will be maintained intraoperatively. Before the start of pneumoperitoneum, inj. Paracetamol 1 gm will be given as infusion. While creating pneumoperitoneum an intra abdominal pressure of <15 mm Hg will be maintained. Neuromuscular block will be reversed with inj. Neostigmine at 0.05 mg/kg and inj. Glycopyrrolate at 0.01 mg/kg. After recovery and extubation, patient will be shifted to post operative care unit.

Postoperative management:

Post operatively, all the patients will be receiving Inj. Paracetamol 1gm 6 hourly as routine analgesic. Inj. Tramadol 1mg/kg in 100ml normal saline will be used as the rescue analgesic and will be given when the pain score, NRS is ≥4 or on patient demand. If pain persists after half an hour, Inj, diclofenac 1mg/kg will be given. Duration of postoperative analgesia (in minutes) will be defined as “time duration from the time of block to the time of demand for first rescue analgesia postoperatively”. Total analgesic consumption in 24 hours will be noted. Occurrence of complications like nausea, vomiting, redness and hematoma at the site of injection within 24 hrs postoperatively will be noted and will be treated accordingly. Patient satisfaction at 24hrs postoperatively will be noted.

Observations:

The following parameters will be assessed in both groups-

1)     Duration of postoperative analgesia (in minutes) (from the time of block to the time of demand for first rescue analgesia postoperatively).

2)     Total requirement of analgesics (in mg) in 24 hours postoperatively.

3)     Numerical Rating Scale of 0-10 at 1,3,6,24 hours after the completion of surgery.

4)     Complications viz. nausea, vomiting, redness and hematoma at the site of injection  within 24 hrs postoperatively.

5)     Patient satisfaction using five-point Likert scale at 24 hrs postoperatively.

Data from patients in whom laparoscopic cholecystectomy was converted to open cholecystectomy will not be included for data analysis. However, the patients will still continue to receive standard postoperative analgesic care and will be monitored for any complications, and will be treated accordingly in the postoperative period.

Operationalizing Serious Adverse Events (SAE)

Local anaesthetic systemic toxicity

Patients will be monitored for local anaesthetic systemic toxicity (LAST) and any such event will be managed as per American Society of Regional Anesthesia (ASRA) checklist.