INTRODUCTION

Cesarean section is one of the life saving major surgeries. The abdominal wall incision and soft tissue dissection associated with this procedure may result in moderate to severe post-operative pain, which adversely affects early ambulation and breastfeeding[1].These patients are routinely managed with oral or intravenous analgesics yet there relative efficacy is still unclear with notable side-effects.[2] Precaution should also be taken with use of nonsteroidal anti-inflammatory drugs (NSAIDs) due to possible adverse effects in elderly patients, patients with renal, cardiac, hematopoietic and liver failure, and in patients with previous history of gastrointestinal bleeding[3].Opioids administration is associated with several systemic complications. Thus, inclination to perform peripheral analgesic procedures such as transverse abdominis plane block is recently increased[4].Transversus abdominis plane(TAP) block or Ilioinguinal/iliohypogastric nerve blocks are few of many analgesic modalities used now a days to achieve optimum Postoperative analgesia following surgery. TAP block is easy to perform and an effective peripheral  abdominal field block that blocks the ilioinguinal, iliohypogastric and lower intercostal nerves[5].With the help of an ultrasound or anatomical landmark, the neurovascular plane of the anterior abdominal wall (where the nerves from T6 to L1 are located) is identified and LA is injected[6].Ropivacaine, a newer LA, has been increasingly used nowadays in different concentration for peripheral nerve blocks[7] Various drugs are used either alone or in combination with local anesthetics in TAPB to provide effective and prolonged analgesia[8]Bupivacaine an amide local anesthetic that has a prolonged duration of action and lower incidence of transient radicular symptoms[9]Magnesium sulfate has been shown to have antinociceptive effects in animal and human models by blocking the N-methyl-D-aspartate (NMDA) receptor and associated calcium channels[10].

STUDY OBJECTIVE

AIM:

To compare the efficacy of Ropivacaine(0.2%) with Magnesium Sulfate versus  Bupivacaine(0.2%)

with Magnesium sulfate in Ultrasound guided bilateral Transverse Abdominis Plane (TAP) block in patients scheduled for Lower Segment Cesarean Section under Subarachnoid Block.

OBJECTIVES:

Primary objective:

To compare the duration of analgesia.

Secondary objective:

To compare additional analgesic requirement in first 24 hours.

To compare the intensity of pain using VAS score

STUDY DESIGN

Prospective randomized double blind study

SAMPLE SIZE

With non response rate 10% = 22+3 =25

Minimum sample size for each group 25 Study type : Interventional

Study design :Prospective , Randomised, Double blind study

Study population :After obtaining Ethical Committee approval and CTRI registration, 50 female patients who will undergo elective or emergency caesarean section at Chettinad Hospital and Research Institute, Kelambakkam, Chennai, will be taken up for study.

Inclusion criteria:

1. American Society of Anaesthesiologists (ASA) grade II,III.

2. Age group between 18-40 years.

3. Scheduled for both elective and emergencyLower Segment Caeserean Section surgeries under Spinal Anaesthesia

Exclusion criteria:

1.Patient refusal

2.Pregnancy induced hypertension Patients  on treatment with Magnesium sulfate

3. History of allergy to study drugs

4. Local site infection

5. Post spinal surgeries, Spinal Deformities

6. Coagulopathy

7. Dysrhythmia  

8. Height < 155cm

9. BMI > 35

10. Altered mental status

Probability sampling:

50 lots by computer generated randomised code (25 in each group) from the people who were willing to take part in the study. All the patients stand an equal chance of getting into any group. All the patients will be aware of the study and informed consent will be obtained.

Sample size:

Group RM (n=25) : patients will receive bilateral USG Guided TAP Block with Ropivacaine 0.2% with Magnesium sulphate (250 mg) 20 ml on each side.

Group BM (n=25) : patients will receive bilateral USG Guided TAP Block with Bupivacaine 0.2% with Magnesium sulfate (250mg) 20ml on each side.

Data collection:

-Age, weight, Duration of surgery, VISUAL ANALOGUE SCALE in 24 hrs, HR, Systolic BP, Diastolic BP, time for first demand of analgesic, total dose of rescue analgesia.

Methodology :

-In the preoperative waiting room, detailed history and physical examination will be done. Baseline data like pulse rate, blood pressure, respiratory rate, and basic investigations will be collected. An  IV access with 18G size IV cannula will be secured for all patients. Proper standard monitoring of pulse oximetry, Non invasive blood pressure, continuous electrocardiogram will be established and baseline variable values will be noted before the procedure.

-Patients will be allocated by computer generated randomized allocation to undergo TAP block Group (RM) will receive 20 ml of 0.2% Ropivacaine with MgSO4 250mg on each side and Group (BM) will receive 20 ml of 0.2% Bupivacaine with MgSO4 250mg on each side The patients, their investigator will be blinded to group assignment.

 -Under asepsis, all patients will undergo spinal anesthesia with 0.5% hyperbaric Bupivacaine 2 ml with fentanyl 0.5ml at L3-L4 or L4-L5 interspace with 26G or 27G Quincke’s spinal needle .Patient’s hemodynamic stability and the level of motor and sensory blockade will be assessed and documented.

 -The bilateral TAP block will be performed after skin closure under monitoring with Ultrasound  guidance ( a high frequency linear probe of 6-19MHz) placed transverse to the abdominal wall, with needle in-plane technique , wherein the  23G  Quincke’s spinal needle will be inserted between the mid and anterior axillary line extending below the rib line to the highest point of the iliac crest under aseptic conditions.

The structures seen from surface to the depth will be external oblique muscle, internal Oblique muscle, transversus abdominis muscle and peritoneal cavity .The needle is placed in between the plane of Internal Oblique muscle and transverse Abdominis muscle, after negative aspiration and as per allocation,study drug will be injected by anaesthetist,the distribution of local anaesthetics was observed as a hypoechoic enlargement upon USG.

-  After completion of TAP block, hemodynamic stability of the patient assessed and each patient will be moved to the postoperative room for monitoring the vitals and adverse events such as-1.Hypotension: Decrease in systolic blood pressure less than 90 mmHg or more than 30 mmHg decrease from the baseline will be considered as Hypotension. It will be managed with IV fluids followed by incremental doses of 6mg of intravenous ephedrine 2.Bradycardia: Heart rate less than 50/min will be considered as Bradycardia and will be managed by incremental doses of 0.3mg intravenous Atropine.  Every patient will be inquired to state the postoperative pain by  means of VAS scale. Time to preliminary reporting of postoperative pain was noted.

END POINTS

This study will be used to compare the efficacy of Ropivacaine (0.2%) with Magnesium sulfate 250mg and

Bupivacaine (0.2%) with Magnesium sulfate 250mg in Transverse abdominis plane block in patients undergoing lower segment cesarean section using subarachnoid block

End point of total duration of analgesia after TAP block will be the preliminary reporting  post operative pain

Additional analgesic requirement if any in the 1st 24 hrs will be noted

VAS score compared postoperatively between 2 groups

ETHICAL CONSIDERATION

After obtaining approval by the Institutional Human Ethics Committee and CTRI registration, and written informed patient consent, 50 patients under ASA physical status II,III patients scheduled for caesarean section both emergency and elective, will be included in a prospective randomized double-blinded clinical trial at Chettinad Hospital and Research Institute, Kelambakkam, chennai.

REFERENCES

Puchakala D, joshi VS, Bhardwaj A. An evaluation of 0.25% bupivacaine vs. 0.375% ropivacaine for postoperative analgesia using ultrasound guided transversus abdominis plane block for cesarean section: A comparative study. J Obstet Anaesth Crit Care 2022;12:17-21

Umalkar M, Londhe N.Evaluation of  magnesium sulfate as an adjuvant to bupivacaine for post operative analgesia in ultrasound –guided TAP block in patients scheduled for lower caesarean segment under subarachnoid block-A Prospective ,randomized, double-blind study. Indian J pain 2020;34:189-92

 wang Y, Wu T, Terry MJ, Eldrige JS, Tong Q, Erwin PJ, et al. Improved perioperative analgesia with ultrasound-guided ilioinguinal/iliohypogastric nerve or transversus abdominis plane block for open inguinal surgery: a systematic review and meta-analysis of randomized controlled trials. J Phys Ther Sci. 2016 Mar; 28(3):1055– 60

Sharma  N, Mehta  N, Sharma  S. An evaluation of 0.25% bupivacaine vs. 0.5% ropivacaine for postoperative analgesia using ultrasound guided transversus abdominis plane block for abdominal surgeries: A comparative study. Indian J Clin Anaesth 2016;3:635-9.