Predicting acute postoperative pain by the Qnox score at the end of surgery: a prospective observational study

Abstract

Background: The QNox score (Quantium Medical S.L., distributed by Fresenius Kabi) has recently been introduced as a tool to quantify intraoperative analgesia. Being based on the analysis of electroencephalographic data, QNox is distinctly different to other methods of nociception monitoring that rely almost entirely on the assessment of sympathetic activity. However, there are currently no published data to validate use of QNox in a clinical setting. We investigated the value of pre-arousal QNox data at the end of surgery for prediction of acute postoperative pain in the PACU. Methods: A total of 150 patients scheduled for non-emergency surgery under sevoflurane-opioid general anaesthesia were included in the study. At the end of surgery but before patient arousal, QNox was measured minutely for 5 min. After admission to the recovery room, pain scores (numeric rating scale [NRS], 0e10) were obtained 5 minutely for 15 min. Results: Data from 144 patients were analysed. QNox before arousal showed no correlation (r¼0.057) with acute postoperative pain in the PACU. Furthermore, the score was found to have no value for the prediction of acute postoperative pain (area under the receiver operating curve, 0.501; 95% confidence interval, 0.406e0.597). Conclusion: QNox at the end of surgery before arousal showed no association with and allowed no prediction of acute pain in the PACU. Clinical trial registration: ACTRN12618001662257.

Relationship between Preoperative Lower Back Pain and Severe Postoperative Pain after Gynecologic Laparoscopy: A Prospective Observational Study

“…To detect such differences, 50 patients in each group (no to mild pain, NRS 0–3; moderate to severe pain, NRS 4–10) were deemed necessary. Based on our clinical experience and previous research [ 7 ], this event rate between the two groups was unlikely to be 1:1 but more likely 2:1. Consequently, 150 patients were included in this study.…”

“…Moreover, pain intensities vary even after the same surgery, which suggests the need for individual evaluation of risk factors for postoperative pain [ 5 , 6 ]. Despite recent advances in anesthesiology, personalized preemptive analgesia remains difficult, with overdosing leading to slow recovery and underdosing leading to severe pain [ 7 ]. Therefore, it will be valuable to identify patients at a high risk of postoperative pain.…”

Real-time evaluation of the independent analgesic efficacy of dexmedetomidine

“…IOC2 detected propofol and sevoflurane provided better analgesia, an effective method to reduce stress and the intraoperative nociceptive stimulus response [ 10 ]. However, another study [ 37 ] showed a lack of correlation between the IOC2 (qNOX) value and postoperative pain; they included different types of surgery with significantly different levels of noxious stimulation. This led to various confounding factors for IOC2 for more specific types of pain.…”

Evaluation of Nociception during Pediatric Surgery: A Topical Review

“…Contrary to adults, the cardiovascular system of children is less frequently affected by diseases or pharmacological therapies, which might lead the anesthesiologist to believe that variations of heart rate and blood pressure are more likely secondary to nociception. Yet, multicenter large morbidity investigations have highlighted that everyday practice in pediatric anesthesia is largely individual-based rather than evidence-based [ 78 , 79 ]. In this view, it appears obvious to seek a monitor that guides the anesthesiologist in the nociception/pain management.…”