Abstract
Effective analgesia after midline laparotomy surgery is essential for enhanced recovery programs. We compared three types of continuous abdominal wall block for analgesia after midline laparotomy for gynaecological oncology surgery. We conducted a single-centre, double-blind randomised controlled trial. Ninety-four patients were randomised into three groups to receive two days of programmed intermittent boluses of ropivacaine (18 ml 0.5% ropivacaine every four hours) via either a transversus abdominis plane (TAP) catheter, posterior rectus sheath (PRS) catheter, or a subcutaneous (SC) catheter. All groups received patient-controlled analgesia with morphine, and regular paracetamol and non-steroidal anti-inflammatory medication. Measured outcomes included analgesic and antiemetic usage and visual analog scores for pain, nausea, vomiting, and satisfaction. Eighty-eight patients were analysed (29 SC, 29 PRS and 30 TAP). No differences in the primary outcome were found (median milligrams morphine usage on day two SC 28, PRS 25, TAP 21, P=0.371). There were differences in secondary outcomes. Compared with the SC group, the TAP group required less morphine in recovery (0 mg versus 6 mg, P=0.01) and reported less severe pain on day one (visual analog scores 36.3 mm versus 55 mm, P=0.04). The TAP group used fewer doses of tropisetron on day one compared with the PRS group (8 versus 21, P=0.016). Programmed intermittent boluses of ropivacaine delivered via PRS, TAP and SC catheters can be provided safely to patients undergoing midline laparotomy surgery. Initially TAP catheters appear superior, reducing early opioid and antiemetic requirements and severe pain, but these advantages are lost by day two.