Systemic ropivacaine diminishes pain sensitization processes: a randomized, double-blinded, placebo-controlled, crossover study in healthy volunteers

Effect of ropivacaine on peripheral neuropathy in streptozocin diabetes-induced rats through TRPV1-CGRP pathway

Objective To determine the effect of ropivacaine on peripheral neuropathy in diabetic rats and its possible mechanism.

Methods Forty-eight Sprague–Dawley rats were randomly divided into six groups: nondiabetic control group, nondiabetic group A (0.25% ropivacaine), nondiabetic group B (0.75% ropivacaine), diabetic control group (diabetic peripheral neuropathy (DPN) +artificial cerebrospinal fluid), diabetic group A (DPN+0.25% ropivacaine), and diabetic group B (DPN + 0.75% ropivacaine), with eight rats in each group. Within an hour of the last administration, the sciatic motor nerve conduction velocity (MNCV) of each group was measured, and the morphological changes of rat sciatic nerve were observed by HE, Weil’s staining and electron microscopy. The expression of transient receptor potential vanilloid (TRPV1) in the spinal cord dorsal horn of rats was analyzed by immunohistochemistry, and the expression of Calcitonin gene-related peptide (CGRP) protein in the spinal cord was analyzed by Western blot.

Results Compared with the nondiabetic control group, elevated blood glucose, decreased weight and reduced average mechanical withdrawal threshold (MWT), additionally, the sciatic nerves showed significantly slowed conduction velocity (both P<0.001) and damaged pathological structure, the expression of TRPV1 and CGRP were decreased (both P<0.001) in the diabetic groups. Compared with the diabetic control group, down-regulation of TRPV1 and CGRP in spinal cord was significant for the diabetic groups A and B treated with 0.25 and 0.75% ropivacaine, the higher concentration of ropivacaine correlated with a greater change.

Conclusion Ropivacaine can significantly block sciatic nerve conduction velocity in DPN rats in a concentration-dependent manner, which may be related to the expression of the TRPV1-CGRP pathway.

Intraperitoneal ropivacaine and early postoperative pain and postsurgical outcomes after laparoscopic herniorrhaphy in toddlers: a randomized clinical trial

BACKGROUND

Postoperative pain can cause physiological distress, postoperative complications, and extended lengths of hospitalized stay. In children, management of postoperative pain is still recognized as being inadequate.

OBJECTIVE

The aim of this trial was to investigate the effects of intraperitoneal ropivacaine on postoperative pain, and recovery of bowel function and emetic events after laparoscopic herniorrhaphy in toddlers.

METHODS

Seventy-six children aged from 9 months to 3 years were recruited between August 2013 and June 2014 at Tongji Hospital and randomly assigned into two groups. One group received intraperitoneal ropivacaine right before surgery and the control group received intraperitoneal saline. A standard combined general anesthesia procedure was performed under regular monitoring. Postoperative pain was assessed by the FLACC scale. Postoperative analgesic consumption, time to flatus, time to first stool, and postoperative emetic events were also recorded.

RESULTS

When compared with the control group, children who received intraperitoneal ropivacaine experienced less pain 0-4 h after surgery [P < 0.001, difference in median FLACC (95% CI) for 2 h time point is 2.00 (0.87-3.13), for 4 h time point is 1.00 (0.55-1.45)]. In addition, the number of toddlers who received analgesia 0-24 h after surgery in the ropivacaine group was lower than that in the control group [P < 0.001, difference in proportions (95% CI) is 0.575 (0.3865-0.7638)]. Compared with the control group, time to flatus in ropivacaine group was also much shorter [21.1 h vs 16.7 h, P = 0.04, difference in mean (95% CI) is 4.4 (1.49-7.28)], and the time to first stool after surgery was earlier in the ropivacaine group [30.7 h vs 25.6 h, P = 0.003, difference in mean (95% CI) is 5.1 (1.78-8.45)]. Furthermore, the incidence of emetic events in the ropivacaine group was significantly lower than the control group [32.4% vs 11.1%, P = 0.03, difference in proportions (95% CI) is 0.212 (0.0246-0.4002)].

CONCLUSION

The present results indicate that intraperitoneal ropivacaine reduces early postoperative pain and improves recovery after laparoscopic herniorrhaphy in toddlers. Therefore, IPLA is a good stratagem for postoperative pain management after laparoscopic surgery in toddlers.