MgSO4 as Adjuvants to Bupivacaine vs Neostigmine in TAP Block in Cesarean Section

Comparative Evaluation of Magnesium Sulphate Versus Neostigmine as an Adjuvant to Bupivacaine in Ultrasound Guided Transversus Abdominis Plane (TAP) Block as Postoperative Analgesia in Cesarean Section

The aim of this study is to compare the duration of analgesia obtained by addition of Neostigmine versus MgSO4 as adjuvants to bupivacaine in TAP block in patients undergoing Cesarean Section and to evaluate postoperative analgesic requirements, side effects and level of patient satisfaction.

Caesarean section (CS) is one of the most operations in the world. Effective postoperative analgesia after it is very important because it encourages breast feeding and facilitates early ambulation and recovery. Postoperative analgesia is too important to prevent unwanted side effects such as venous thromboembolism, respiratory complications and increased hospital stay.Post Caesarean discomfort and pain is expected; so, the analgesic regimen should assure safe and efficient sedation. Commonly, opioids and NSAIDs are used for post caesarean pain relief. While dose dependent respiratory depression is the most discomforting side effect, other insignificant side effects such as gastrointestinal upset, pruritus and urinary retention can be annoying during the first hours of puerperium. The transversus abdominus plane (TAP) block has been used for postoperative pain relief in different abdominal surgeries as part of the multimodal anesthetic approach.It creates satisfactory somatic anesthesia with no visceral blockade. Its widespread use in abdominal surgeries is due to its technical simplicity and trustworthy analgesia .This block implies administering local anesthetic between the internal oblique muscle and transversus abdominis muscle, which is marked by the lumbar Petit triangle. The primary drawback of single-shot regional blocks is their short duration of action when administered with local anesthetic alone. Several adjuvants, including opioids, alpha 2 agonists,Neostigmine, N-methylD-aspartate (NMDA) receptor antagonists, and other drugs, have been utilized to extend the duration of blocks . Opioids are by far the most often used adjuvants, but they accompany a host of unpleasant side effects, such as respiratory depression, drowsiness, nausea, and vomiting. In some studies, using alpha 2 agonists such as Dexmedetomidine and Clonidine has been related to drowsiness and bradycardia .

MgSO4 is an N-methyl-D-aspartate (NMDA) receptor antagonist. It acts by non-competitive antagonism blocking the voltage-dependent ion channels.

The potential of neostigmine as an adjuvant in peripheral nerve block is through its action to increase acetylcholine at muscarinic junctions of peripheral nerves. 500 mcg neostigmine was used as adjuvant to local anesthetic in an axillary brachial plexus block leads to decreased pain and less use of analgesics in the first 24 hours postoperatively with no incidence of adverse effects

Inclusion Criteria:

• Age from 19 to 40 years old
• Singleton pregnencies with a gestational age of at least 37 weeks
• American society of anesthesiologists (ASA) physical state I , II
• patients undergoing spinal anesthesia for cesarean delivery via Pfannenstiel incision with exteriorization of the uterus.

Exclusion Criteria:

• Patient's refusal
• Age < 19 or > 40 years
• Height<150 cm, weight < 60 kg, body mass index (BMI) ≥40 kg/m2.
• Contraindications to spinal anesthesia (Coagulopathy, increased intracranial pressure, or local skin infection).
• Cardio-respiratory conditions
• Convulsions
• Inability to comprehend or participate in the pain scoring system.
• Bleeding diathesis
• Known allergy to any drugs used in this study