The effect of addition of magnesium sulfate or dexamethasone to bupivacaine on the post-operative analgesic duration of ultrasound-guided quadratus lumborum block in open abdominal surgeries: a comparative study

Abstract Background The aim of this study was to assess the effect addition 500-mg magnesium sulfate (MgSo 4 ) or 8-mg dexamethasone bupivacaine in bilateral ultrasound-guided quadratus lumborum block (QLB), on duration post-operative analgesia, patient’s hemodynamic parameters, severity pain, number patients who required rescue total dose pethidine given, maintained analgesia for 36 h, and time first ambulation. Sixty-six patients, 18 65 years old, with body weight 60–90 kg, scheduled undergo elective open abdominal surgeries under general anesthesia, were randomly divided into three equal groups: Bupivacaine-Magnesium QLB group (BM) Bupivacaine-Dexamethasone (BD) Bupivacaine-Saline (BS) patients. Results visual analogue scale (VAS) at rest movement comparable between upon arrival care unit (PACU), PACU, 2, 4, 6, 8, 12, 24, h. At 30 hours, VAS statistically significantly lower BD 2 (0–4) 2.75 (2–4.5) than BM 2.25 3 (0–4.5), BS 3.25 (3–4) (3.5–5), respectively, P -value ˂ 0.001. Although 100% received pethidine, versus 68.2% 63.6% BD, 0.007, cumulative doses h groups 0.170, 0.239, 0.231, respectively. Conclusions In surgeries, MgSo reduced scores experiencing moderate pain fewer receiving less showing better results.