Comparison between adenosine and magnesium sulfate as an adjuvant for ultrasound-guided rectus sheath block. A prospective randomized controlled study.

Background: Rectus sheath block (RSB) is an effective nerve block. This study aimed to compare adenosine and magnesium sulfate as an adjuvant for ultrasound-guided RSB (UGRSB). Methods: This prospective controlled randomized trial was performed on 96 adult patients (ASA I and II) undergoing umbilical or epigastric hernia repair. The patients were assigned randomly to three equal groups and got bilateral UG-RSB. Adenosine group: using 20 ml bupivacaine hydrochloride 0.25% + 12 mg of adenosine (4 ml) +1 ml saline 0.9%. Magnesium group: using 20 ml bupivacaine hydrochloride 0.25% + 500 mg of magnesium sulfate (5 ml). Control group: using 20 ml bupivacaine hydrochloride 0.25% + 5 ml of saline 0.9%. Registration No.: 6/2018ANET17. Results: A significant postoperative reduction of VAS up to 18 h was detected in the magnesium sulfate group and up to 12 h was detected in the adenosine group. A statistically significant prolongation of time to the first analgesia in magnesium and adenosine groups than control groups (483.44 ± 48.03 & 415.28 ± 29.81 than 325.31 ± 50.29, respectively), as well as the mean postoperative morphine consumption was 5.94 ± 1.61, 8.03 ± 1.0 and 16.69 ± 2.49 among magnesium, adenosine, and control groups, respectively. The postoperative complications were statistically significantly higher in the control group. Conclusion: This study validates the effectiveness of adenosine versus magnesium sulfate as good adjuvants for improving the quality and duration of UG-RSB and reduction of postoperative narcotic requirements. However, the duration was relatively longer with magnesium sulfate. [ABSTRACT FROM AUTHOR]