[Postoperative opioids, endocrine changes,and immunosuppression]

Postoperative analgesic effect of intravenous coinjection of lidocaine and dexmedetomidine in gynaecological surgery: a systematic review and meta-analysis

OBJECTIVES

Hysterectomy or myomectomy is a common gynaecological procedure that results in moderate to severe acute postoperative pain, which can cause many adverse effects. This study aimed to compare the postoperative analgesic efficacy, opioid consumption, quality of postoperative recovery (QOR) and adverse reactions of intravenous coinjection of lidocaine and dexmedetomidine versus lidocaine or dexmedetomidine alone in gynaecological surgery.

DESIGN

Systematic review and meta-analysis was performed.

DATA SOURCES

The PubMed, Embase, Cochrane Library and Web of Science databases were used to access the articles. Electronic databases were searched for eligible studies published before 1 May 2024.

ELIGIBILITY CRITERIA

All randomised controlled trials (RCTs) were included in the final analysis in which the intraoperative intervention group received intravenous coinjection of lidocaine and dexmedetomidine, and the control group received intravenous injection of lidocaine or dexmedetomidine alone in gynaecologic procedures.

DATA EXTRACTION AND SYNTHESIS

Study retrieval, literature screening, data extraction and risk of bias assessment were performed independently by two reviewers. The quality of included studies was assessed by the Cochrane Collaboration Risk of Bias (ROB V.2.0). Data were expressed as standardised mean difference, weighted mean difference or relative risk with 95% CI. Review Manager V.5.4 was used for data analysis.

RESULTS

A total of five RCTs were included, involving 672 patients, of which 224 patients received coinjection of lidocaine and dexmedetomidine. The results revealed that coinjection of lidocaine and dexmedetomidine was superior to individual lidocaine in the visual analogue scale (VAS) scores at 1 hour (MD=-0.90, 95% CI (-1.11 to -0.69), p<0.001), 2 hours (MD=-0.99, 95% CI (-1.19 to -0.80), p<0.001), 4 hours (MD=-1.20, 95% CI (-1.75 to -0.66), p<0.001), 6 hours (MD=-1.09, 95% CI (-1.48 to -0.70), p<0.001), 8 hours (MD=-1.22, 95% CI (-1.61 to -0.83), p<0.001) and 12 hours (MD=-0.76, 95% CI (-1.35 to -0.17), p=0.o1) after surgery. Compared with the dexmedetomidine group, the lidocaine+dexmedetomidine group had low VAS scores at 1 hour (MD=-0.60, 95% CI (-0.83 to -0.37), p<0.001), 2 hours (MD=-0.70, 95% CI (-0.87 to -0.53), p<0.001), 6 hours (MD=-0.79, 95% CI (-0.98 to -0.59), p<0.001), 8 hours (MD=-0.77, 95% CI (-1.25 to -0.28), p=0.002) and 12 hours (MD=-0.56, 95% CI (-1.00 to -0.11), p=0.01) after surgery. Coinjection of lidocaine and dexmedetomidine resulted in significantly lower postoperative opioid consumption, postoperative nausea and vomiting and bradycardia than lidocaine alone (all p<0.05). Compared with the dexmedetomidine group, the lidocaine+dexmedetomidine group shortened the time to intestinal transit resumption (p=0.003). Coinjection of lidocaine and dexmedetomidine reduced intraoperative opioid consumption and increased QOR scores compared with lidocaine and dexmedetomidine alone (all p<0.05).

CONCLUSION

Lidocaine combined with dexmedetomidine had superior analgesic efficacy and safety. However, due to the limitation in the number of available studies, more large-scale, prospective RCTs are needed for further investigation.PROSPERO registration numberCRD42023384018.

Clinical Management of Pain in Rodents

The use of effective regimens for mitigating pain remain underutilized in research rodents despite the general acceptance of both the ethical imperative and regulatory requirements intended to maximize animal welfare. Factors contributing to this gap between the need for and the actual use of analgesia include lack of sufficient evidence-based data on effective regimens, under-dosing due to labor required to dose analgesics at appropriate intervals, concerns that the use of analgesics may impact study outcomes, and beliefs that rodents recover quickly from invasive procedures and as such do not need analgesics. Fundamentally, any discussion of clinical management of pain in rodents must recognize that nociceptive pathways and pain signaling mechanisms are highly conserved across mammalian species, and that central processing of pain is largely equivalent in rodents and other larger research species such as dogs, cats, or primates. Other obstacles to effective pain management in rodents have been the lack of objective, science-driven data on pain assessment, and the availability of appropriate pharmacological tools for pain mitigation. To address this deficit, we have reviewed and summarized the available publications on pain management in rats, mice and guinea pigs. Different drug classes and specific pharmacokinetic profiles, recommended dosages, and routes of administration are discussed, and updated recommendations are provided. Nonpharmacologic tools for increasing the comfort and wellbeing of research animals are also discussed. The potential adverse effects of analgesics are also reviewed. While gaps still exist in our understanding of clinical pain management in rodents, effective pharmacologic and nonpharmacologic strategies are available that can and should be used to provide analgesia while minimizing adverse effects. The key to effective clinical management of pain is thoughtful planning that incorporates study needs and veterinary guidance, knowledge of the pharmacokinetics and mechanisms of action of drugs being considered, careful attention to individual differences, and establishing an institutional culture that commits to pain management for all species as a central component of animal welfare.