A Systematic Review of Postoperative Pain Outcome Measurements Utilised in Regional Anesthesia Randomized Controlled Trials

Abstract

Introduction Regional anesthesia is a rapidly growing subspecialty. There are few published meta-analyses exploring pain outcome measures utilised in regional anesthesia randomized controlled trials (RCTs), which may be due to heterogeneity in outcomes assessed. This systematic review explores postoperative pain outcomes utilised in regional anesthesia RCTs. Methods A literature search was performed using three databases (Medline, Embase, and CINAHL). Regional anesthesia RCTs with postoperative pain as a primary outcome were included if written in English and published in one of the top 20 impact factor journals between 2005 and 2017. Study quality was assessed using the Cochrane Collaboration's tool for assessing risk of bias. Results From the 31 included articles, 15 different outcome measures in total were used to assess postoperative pain. The most commonly (16/31) used outcome measures were verbal numerical grading of pain out of 10, total opioid consumption, and visual analogue scale 10 cm (VAS). The need for analgesia was used as an outcome measure where studies did not use a pain rating score. Ten studies reported pain scores on activity and 27/31 studies utilised ≥2 pain outcomes. Time of measurement of pain score also varied with a total of 51 different time points used in total. Conclusion Analysis of the articles demonstrated heterogeneity and inconsistency in choice of pain outcome and time of measurement within regional anesthesia studies. Identification of these pain outcomes utilised can help to create a definitive list of core outcomes, which may guide future researchers when designing such studies.

fNIRS brain measures of ongoing nociception during surgical incisions under anesthesia

“…Other elements, such as nerve thickness, concentration and volume of the local anesthetic may affect the magnitude of the nerve block and outcome. 106 , 107 Finally, there is evidence from clinical blocks that afferent activity still arrives at the central nervous system during local anesthesia in patients who are completely pain-free, that is, acutely, all sensation can be lost without blocking all impulses. The contribution of A-Beta nociceptive fibers in this situation is unknown.…”

Perineural local anaesthetic catheter after major lower limb amputation trial (PLACEMENT): results from a randomised controlled feasibility trial

“…Use of a numerical rating scale had better compliance in the majority of studies reporting this, and was the recommended tool in 11 of the studies. A more recent systematic review of postoperative pain reporting after regional analgesia identified 15 different outcome measures used in 31 different studies, with some including pain on movement as well as at rest 40. Five studies recorded maximal pain score during the study period.…”

Methods used in the selection of instruments for outcomes included in core outcome sets have improved since the publication of the COSMIN/COMET guideline

“…Of the 118 studies, six studies (5%) [35e40] considered both the results of the measurement properties of the outcome measurement instruments and the quality of studies on these measurement properties. However, in three of these studies [35,36,38], it remains unclear whether a best evidence synthesis was performed. COS developers of 23 of 118 studies (20%) only considered the results of the measurement properties of the included outcome measurement instruments but did not consider the quality of the studies on these measurement properties.…”

“…Of the 118 studies, only 11 studies (9%) recommended one single instrument for each core outcome included in the COS [12,38,39,41e48]. In seven of these 11 studies, one instrument was selected for each core outcome (range: 4e26) in the COS [12,38,41,43,44,47,48]. In three studies, one instrument was recommended for each core outcome or for each subpopulation (i.e., children and adolescents; range of core outcomes: 4e10) [42,45,46].…”