Treatment
To evaluate the effect of continuous ropivacaine subfascial wound infusion after caesarean delivery patients were randomly allocated in two groups receiving either ropivacaine 0.2 % (Ropivacaine, 2 mg/ml, Fresensius Kabi) (ropivacaine group) or NaCl 0.9 % (placebo group) into the wound catheter. Group allocation was done using a computer-generated randomization and was concealed in sealed envelopes until start of surgery. Based on this information, a fix member of the midwife team who will otherwise not be involved in the study, prepared the injections for the elastomeric pump with either ropivacaine 0.2 % or NaCl 0.9 % so that only they were aware of the product that was administered through the catheter.
At the time of surgery, all of the patients received a standardized spinal anaesthesia with 8 - 10 mg of hyperbaric bupivacaine 0.5 % (Marcaine, AstraZeneca) combined with 2 - 2.5 μg of sufentanil (Sufenta, Janssens-Cilag) based on clinicians’ discretion. If inadequate spinal anaesthesia occurred, general anaesthesia was performed, and the patient had been excluded from the study.
All caesarean sections were done by Pfannenstiel incision followed by transverse lower uterine segment incision. Near the end of the procedure the parietal peritoneum was closed with a running absorbable suture. After this, a multi-holded catheter (PAINfusor catheter 15 cm; Baxter, Amaro, Italy) was placed along the full length of the wound between the closed parietal peritoneum and the fascia transversalis. In the end, the gynaecologist closed the fascial layer and skin followed by securing the catheter to the skin. A 5 ml solution, ropivacaine 0.2 % or NaCl 0.9 %, depending on group allocation, was administered through the catheter during the surgical intervention to evaluate his permeability. In the ropivacaine group, ropivacaine 0.2 % was injected through the catheter, by an elastomeric pump infusor (Infusor LV 7 mL/h; Baxter) at a rate of 7 ml/h for 48 hours. In the placebo group, NaCl 0.9 % was injected through the catheter, by an elastomeric pump infusor at a rate of 7 ml/h for 48 hours.
Post caesarean, all patients received a strictly identical multimodal analgesic treatment. A patient-controlled analgesia (PCA) device (CADD, Solis 2110, Smiths Medical, St. Paul, USA) was placed in the postanesthesia care unit (PACU) and set to deliver a 2 mg dose of morphine with a 10-minute lockout time and a maximum allowed dose of 20 mg per 4 hours. Paracetamol 1 g four times a day and diclofenac 75 mg two times a day, both intravenous administrated, were systematically given in the first 48 hours. After 48 hours, the PCA device and all other intravenous therapies were stopped, and oral analgesics were given on demand based on the WHO ladder. Rescue intravenous antiemetics (metoclopramide 10 mg and if insufficient ondansetron 4 mg) were administered if postoperative nausea/vomiting developed. Pruritus was treated by subcutaneous naloxone (0.4 mg) administration. Pre-operative ulcer prevention (ranitidine 150 mg) and post-operative thromboembolism prophylaxis (enoxaparine 0.4 ml) was performed according to international guidelines. Urine bladder catheter was left in place for at least 24 hours after surgery.