Systematic reviews and meta-analyses present results by combining and analyzing data from different studies conducted on similar research topics. In recent years, systematic reviews and meta-analyses have been actively performed in various fields including anesthesiology. These research methods are powerful tools that can overcome the difficulties in performing large-scale randomized controlled trials. However, the inclusion of studies with any biases or improperly assessed quality of evidence in systematic reviews and meta-analyses could yield misleading results. Therefore, various guidelines have been suggested for conducting systematic reviews and meta-analyses to help standardize them and improve their quality. Nonetheless, accepting the conclusions of many studies without understanding the meta-analysis can be dangerous. Therefore, this article provides an easy introduction to clinicians on performing and understanding meta-analyses.

SUMMARY Background

ObjectiveTo evaluate the effects of anaesthesia on postoperative outcome in elderly patients who underwent hip fracture surgery.SettingNationwide National Health Insurance Sharing Service database of Korea.ParticipantsAll patients aged ≥65 years old who underwent hip fracture surgery, covered by the Korean National Health Insurance, between 1 January 2009 and 31 December 2015.InterventionsHip fracture surgery under general anaesthesia (group GA) or regional anaesthesia (group RA), with a principal diagnosis of femoral fracture.Primary and secondary outcome measuresThe primary outcome was the anaesthetic-type effect on 30-day mortality and the secondary outcome was postoperative delirium requiring pharmacological intervention.ResultsAmong the 96 289 patients who underwent hip fracture surgery, 25 593 and 70 696 patients received GA and RA, respectively. After propensity score matching, 25 593 remained in each group. Postmatching mortality was lower in the RA than in the GA group (574 (2.24%) vs 654 (2.55%), p=0·0047, 95% CI −0.0099 to 0.0159). Delirium incidence was lower in the RA than in the GA group (5187 (20.27%) vs 5828 (22.77%), p<0·0001, 95% CI 0.019 to 0.045). The incidence of intensive care unit stay and ventilator care was lower in the RA than in the GA group (5838 (22.1%) vs 8055 (31.47%), p<0·0001, 95% CI 0.046 to 0.070 and 459 (1.73%) vs 1207 (4.72%), p<0·0001, 95% CI −0.0024 to 0.023, respectively).ConclusionRA was associated with better outcomes than GA, in terms of mortality, delirium, intensive care unit admission and ventilator care, in elderly patients who underwent hip fracture surgery.

A perioperative intravenous lidocaine infusion has been reported to decrease postoperative pain. The goal of this study was to evaluate the effectiveness of intravenous lidocaine in reducing postoperative pain for laparoscopic colectomy patients. Fifty-five patients scheduled for an elective laparoscopic colectomy were randomly assigned to 2 groups. Group L received an intravenous bolus injection of lidocaine 1.5 mg/kg before intubation, followed by 2 mg/kg/h continuous infusion during the operation. Group C received the same dosage of saline at the same time. Postoperative pain was assessed at 2, 4, 8, 12, 24, and 48 hours after surgery by using the visual analog scale (VAS). Fentanyl consumption by patient-controlled plus investigator-controlled rescue administration and the total number of button pushes were measured at 2, 4, 8, 12, 24, and 48 hours after surgery. In addition, C-reactive protein (CRP) levels were checked on the operation day and postoperative days 1, 2, 3, and 5. VAS scores were significantly lower in group L than group C until 24 hours after surgery. Fentanyl consumption was lower in group L than group C until 12 hours after surgery. Moreover, additional fentanyl injections and the total number of button pushes appeared to be lower in group L than group C (P , 0.05). The CRP level tended to be lower in group L than group C, especially on postoperative day1 and 2 and appeared to be statistically significant. The satisfaction score was higher in group L than group C (P ¼ 0.024). Intravenous lidocaine infusion during an operation reduces pain after a laparoscopic colectomy.