Intravenous Dexmedetomidine Combined with Ultrasound-Guided Rectus Sheath Block for Open Gastrectomy: a Prospective Randomized Trial

Abstract

Purpose: To compare the incidences of positive hemodynamic response (HR > 100 beats min^-1 or SBP > 160 mmHg) during abdominal exploration and moderate pain after surgery, when using dexmedetomidine infusion and rectus sheath block.

Methods: One hundred patients undergoing open gastrectomy were randomized to receive rectus sheath block with ropivacaine (Group B, n = 25), initial loading dose of 0.6 μg kg^-1 dexmedetomidine, followed by a continuous infusion of 0.2 μg kg^-1 h^-1 throughout surgery (Group D, n = 25), both rectus sheath block and dexmedetomidine (Group BD, n = 25), or neither rectus sheath block nor dexmedetomidine (Group C, n = 25). General anesthesia techniques were standardized. HR, SBP, and positive hemodynamic response at peritoneum incision (T_PI), 5 min (T_AE-5), 10 min (T_AE-10), and 15 min (T_AE-15) after the start of abdominal exploration, and incidences of moderate postoperative pain were recorded.

Results: Positive hemodynamic responses during abdominal exploration were more common in Groups B (82%) and C (74%) than in Groups D (14%) and BD (9%) (all P = 0.000). HR and SBP were lower in Groups D and BD, compared with those in Groups C and B (all P < 0.05). Compared with T_PI, HR and SBP increased significantly in Groups B and C during abdominal exploration (all P < 0.05)_, but not in Group BD (except HR at T_AE-15). The incidences of moderate pain in Groups B and BD were noticeably lower than in Groups C and D at 1 h, 2 h, and 6 h after surgery (all P < 0.0083).

Conclusion: Dexmedetomidine infusion combined with rectus sheath block provided more hemodynamic stability during abdominal exploration and better analgesia after surgery.

Keywords: Abdominal exploration; Dexmedetomidine; Gastrectomy; Rectus sheath block.