The analgesic efficacy of patient-controlled ropivacaine instillation after Cesarean delivery.

Abstract

To assess the efficacy and safety of wound instillation of ropivacaine, when administered via a patient-controlled elastometric pump, 50 term parturients undergoing cesarean delivery were enrolled into this prospective, placebo-controlled, double-blinded study. In all cases, a standard spinal anesthetic was administered. After the surgery, a multihole 20-gauge epidural catheter (B. Braun, Melsungen, Germany) was placed above the fascia such that the tip was sited at the point that demarcated 50% of the length of the surgical wound. Thereafter, the catheter was connected to the elastometric pump. According to a computer-generated randomization schedule, the pump was filled with either ropivacaine 0.2% (Ropivacaine Group) or an equal volume of sterile water (Control Group). Postoperatively, patient-controlled analgesia was administered via the elastometric pump. During the first 6 postoperative hours, a coinvestigator administered "rescue" morphine (2 mg, IV). Thereafter, "rescue" dipyrone (1 g) was administered on patient request. In a subset of 10 patients, blood ropivacaine levels were assessed. Compared with the Control Group, significantly fewer patients in the Ropivacaine Group received "rescue" morphine (92% vs. 48%, respectively) (P<0.01). The total "rescue" morphine administered during the first 6 postoperative hours was 2+/-3 mg vs. 10+/-5 mg (P<0.01) for the Ropivacaine and Control Groups, respectively. Patient-generated resting pain scores were similar between the groups. However, pain scores generated after coughing and leg raise were significantly (P<0.04) less in the Ropivacaine Group. More patients in the Ropivacaine Group than in the Control Group described their analgesia as good or excellent. In the subset of patients (n = 10) studied, unbound ropivacaine blood levels were below the toxic threshold (600 ng/mL). However, blood ropivacaine accumulation was noted. All patients stated that the elastometric pump was easy to use. Ropivacaine wound instillation via an elastometric pump is a simple technique that provides safe and effective analgesia after cesarean delivery.