Midazolam has been used in regional anesthesia of brachial plexus block; it has offered accepted postoperative pain relief. This study will use it in as an adjuvant to bupivacaine 0.25% in quadratus lumborum block in caesarean section

It is vital to apply adequate postoperative analgesia following Caesarean section (C-section), since it will affect the distinct surgical recovery requirements of the parturient. The ultrasound-guided quadratus lumborum block (QLB), first introduced by Blanco R. in 2007, has been recognized as an effective abdominal wall block approach, in which local anesthetic injected from the posterior abdomen will spread around the quadratus lumborum muscle and block the intermuscular nerves. In addition, such block is also closely related to multiple sympathetic fibres and is connected to the thoracic paravertebral space. Typically, QLB is found to be effective, which can provide satisfactory analgesic effect.

Midazolam is one of the clinically water-soluble benzodiazepines and effective to produce the analgesic effect through the neuraxial pathways. The organs and joints of humans have the benzodiazepine receptor, and midazolam is revealed to produce the analgesic effect through the gamma-aminobutyric acid receptors (GABA) in the spinal cord. Previous studies have reported that the midazolam (75 μg/kg) through the intraarticular route can decrease the pain intensity for arthroscopic knee surgery. In addition, the intrathecal midazolam (2 mg) is reported to prolong the duration of analgesia without any adverse effects following knee arthroscopies. Perineural midazolam has been also evaluated in brachial plexus block.

Inclusion Criteria:

• American Society of Anesthesiologists (ASA) physical status I or II
• age from 24 to 40 years old
• weight from 50 to 80 kg,
• normal singleton pregnancy with a gestation of at least 37 weeks

Exclusion Criteria:

• Coagulopathy
• maternal anatomic abnormalities in the block region
• localized infection
• incapable of comprehending or using the verbal rating pain scoring system
• Included medications allergy
• history of chronic pain or regular opioid use.

pregnancy with a gestation of at least 37 weeks