Using diagnostic testing to determine the presence or absence of a disease is essential in clinical practice. In many cases, test results are obtained as continuous values and require a process of conversion and interpretation and into a dichotomous form to determine the presence of a disease. The primary method used for this process is the receiver operating characteristic (ROC) curve. The ROC curve is used to assess the overall diagnostic performance of a test and to compare the performance of two or more diagnostic tests. It is also used to select an optimal cut-off value for determining the presence or absence of a disease. Although clinicians who do not have expertise in statistics do not need to understand both the complex mathematical equation and the analytic process of ROC curves, understanding the core concepts of the ROC curve analysis is a prerequisite for the proper use and interpretation of the ROC curve. This review describes the basic concepts for the correct use and interpretation of the ROC curve, including parametric/nonparametric ROC curves, the meaning of the area under the ROC curve (AUC), the partial AUC, methods for selecting the best cut-off value, and the statistical software to use for ROC curve analyses.

Nahm FS. Korean J Anesthesiol. 2016 Feb;69(1):8-14. http://dx.doi.org/10.4097/kjae.2016.69.1.8

The use of gamification in healthcare has been gaining popularity. This prospective, randomized, clinical trial was designed to evaluate whether gamification of the preoperative process—via virtual reality (VR) gaming that provides a vivid, immersive and realistic experience—could reduce preoperative anxiety in children. Seventy children scheduled for elective surgery under general anesthesia were randomly divided into either the control or gamification group. Children in the control group received conventional education regarding the preoperative process, whereas those in the gamification group played a 5 min VR game experiencing the preoperative experience. Preoperative anxiety, induction compliance checklist (ICC), and procedural behavior rating scale (PBRS) were measured. Sixty-nine children were included in the final analysis (control group = 35, gamification = 34). Preoperative anxiety (28.3 [23.3–36.7] vs. 46.7 [31.7–51.7]; p < 0.001) and intraoperative compliance measured using ICC (p = 0.038) were lower in the gamification group than in the control group. However, PBRS (p = 0.092) and parent/guardian satisfaction (p = 0.268) were comparable between the two groups. VR experience of the preoperative process could reduce preoperative anxiety and improve compliance during anesthetic induction in children undergoing elective surgery and general anesthesia.

Nahm FS. Korean J Pain. 2017 Oct;30(4):241-242. https://doi.org/10.3344/kjp.2017.30.4.241

A virtual reality (VR) tour of the operating theatre could reduce preoperative anxiety by providing a realistic experience for children. This randomized clinical trial was designed to determine whether parental co-experience of preoperative VR tour through a mirroring display could further reduce preoperative anxiety. Eighty children scheduled for elective surgery under general anesthesia were randomly allocated into either the control or mirroring group. Children in the control group watched a 4-min immersive VR video showing the operating theatre and explaining the preoperative process, via a head mounted display. In the mirroring group, parents of children watched the same video through mirroring display concurrently while their child experienced the immersive VR tour. Preoperative anxiety and satisfaction score were measured. Eighty children completed the final analysis (control group = 40, mirroring group = 40). Preoperative anxiety of children (p = 0.025) and parents (p = 0.009) were lower in the mirroring group compared with the control group. Parents' satisfaction in the mirroring group was significantly higher than those in the control group (p = 0.008). Parental co-experience of the VR tour with children through mirroring the display was effective in reducing preoperative anxiety in both children and parents.

Staged bilateral total knee arthroplasty (TKA) may provide an ideal clinical model for the study of central sensitization. In staged TKA, hyperalgesia may be induced as a result of repeated surgical injury possibly via central sensitization, which can decrease functional outcomes. Therefore, we hypothesized that in staged bilateral TKA, patients would have greater pain in the second operated knee than in the first. Thirty patients undergoing staged bilateral TKA at a 1-week interval were enrolled. Postoperative pain, which was reported on the basis of a visual analog scale (VAS; primary outcome) at rest and at maximum knee flexion, and the amount of patient-controlled analgesic (i.v. fentanyl) and rescue analgesic (i.v. ketoprofen; secondary outcomes) administered during the 48 h after the operation, were compared between the first and second TKA. VAS scores at rest and at maximum knee flexion were greater on the second operated knee (P<.001 and P<.01, respectively). The cumulative amounts of patient-controlled analgesic and the rescue analgesic were greater in the second than in the first TKA (P<.001 and P<.05, respectively). Patients undergoing staged bilateral TKA experience greater postoperative pain in the second operated knee than the first. This suggests extension of hyperalgesia beyond the initially injured site to remote regions after surgical injury, in which central sensitization may be involved. Therapeutic approaches to reduce such hyperalgesia induced in the course of staged operations are required.