Acute Pain Research Research Articles

Big Data in Studying Acute Pain and Regional Anesthesia.

The digital transformation of healthcare is advancing, leading to an increasing availability of clinical data for research. Perioperative big data initiatives were established to monitor treatment quality and benchmark outcomes. However, big data analyses have long exceeded the status of pure quality surveillance instruments. Large retrospective studies nowadays often represent the first approach to new questions in clinical research and pave the way for more expensive and resource intensive prospective trials. As a consequence, the utilization of big data in acute pain and regional anesthesia research has considerably increased over the last decade. Multicentric clinical registries and administrative databases (e.g., healthcare claims databases) have collected millions of cases until today, on which basis several important research questions were approached. In acute pain research, big data was used to assess postoperative pain outcomes, opioid utilization, and the efficiency of multimodal pain management strategies. In regional anesthesia, adverse events and potential benefits of regional anesthesia on postoperative morbidity and mortality were evaluated. This article provides a narrative review on the growing importance of big data for research in acute postoperative pain and regional anesthesia.

Participants with mild, moderate, or severe pain following total hip arthroplasty. A sub-study of the PANSAID trial on paracetamol and ibuprofen for postoperative pain treatment

In this sub-study of the 'Paracetamol and Ibuprofen in Combination' (PANSAID) trial, in which participants were randomised to one of four different non-opioids analgesic regimen consisting of paracetamol, ibuprofen, or a combination of the two after planned primary total hip arthroplasty, our aims were to investigate the distribution of participants' pain (mild, moderate or severe), integrate opioid use and pain to a single score (Silverman Integrated Approach (SIA)-score), and identify preoperative risk factors for severe pain. We calculated the proportions of participants with mild (VAS 0-30mm), moderate (VAS 31-60mm) or severe (VAS 61-100mm) pain and the SIA-scores (a sum of rank-based percentage differences from the mean rank in pain scores and opioid use, ranging from-200 to 200%). Using logistic regression with backwards elimination, we investigated the association between severe pain and easily obtainable preoperative patient characteristics. Among 556 participants from the modified intention-to-treat population, 33% (95% CI: 26-42) (Group Paracetamol+Ibuprofen (PCM+IBU)), 28% (95% CI: 21-37) (Group Paracetamol (PCM)), 23% (95% CI: 17-31) (Group Ibuprofen (IBU)), and 19% (95% CI: 13-27) (Group Half Strength-Paracetamol+Ibuprofen (HS-PCM+IBU)) experienced mild pain 6h postoperatively during mobilisation. Median SIA-scores during mobilisation were: Group PCM+IBU:-48% (IQR:-112 to 31), Group PCM: 40% (IQR:-31 to 97), Group IBU:-5% (IQR:-57 to 67), and Group HS-PCM+IBU: 6% (IQR:-70 to 74) (overall difference: p=0.0001). Use of analgesics before surgery was the only covariate associated with severe pain (non-opioid: OR 0.50, 95% CI: 0.29-0.82, weak opioid 0.56, 95% CI: 0.28-1.16, reference no analgesics before surgery, p=0.02). Only one third of participants using paracetamol and ibuprofen experienced mild pain after total hip arthroplasty and even fewer experienced mild pain using each drug alone as basic non-opioid analgesic treatment. We were not able, in any clinically relevant way, to predict severe postoperative pain. A more extensive postoperative pain regimen than paracetamol, ibuprofen and opioids may be needed for a large proportion of patients having total hip arthroplasty. SIA-scores integrate pain scores and opioid use for the individual patient and may add valuable information in acute pain research.

The Relationship Between Corticomotor Reorganization and Acute Pain Severity: A Randomized, Controlled Study Using Rapid Transcranial Magnetic Stimulation Mapping.

Although acute pain has been shown to reduce corticomotor excitability, it remains unknown whether this response resolves over time or is related to symptom severity. Furthermore, acute pain research has relied upon data acquired from the cranial "hotspot," which do not provide valuable information regarding reorganization, such as changes to the distribution of a painful muscle's representation within M1. Using a novel, rapid transcranial magnetic stimulation (TMS) mapping method, this study aimed to 1) explore the temporal profile and variability of corticomotor reorganization in response to acute pain and 2) determine whether individual patterns of corticomotor reorganization are associated with differences in pain, sensitivity, and somatosensory organization. Corticomotor (TMS maps), pain processing (pain intensity, pressure pain thresholds), and somatosensory (two-point discrimination, two-point estimation) outcomes were taken at baseline, immediately after injection (hypertonic [n = 20] or isotonic saline [n = 20]), and at pain resolution. Follow-up measures were recorded every 15 minutes until 90 minutes after injection. Corticomotor reorganization persisted at least 90 minutes after pain resolution. Corticomotor depression was associated with lower pain intensity than was corticomotor facilitation (r = 0.47 [P = 0.04]). These effects were not related to somatosensory reorganization or peripheral sensitization mechanisms. Individual patterns of corticomotor reorganization during acute pain appear to be related to symptom severity, with early corticomotor depression possibly reflecting a protective response. These findings hold important implications for the management and potential prevention of pain chronicity. However, further research is required to determine whether these adaptations relate to long-term outcomes in clinical populations.

Attitudes toward the use of animals in chronic versus acute pain research: results of a web-based forum.

When asked about the use of animals in biomedical research, people often state that the research is only acceptable if pain and distress are minimised. However, pain is caused when the aim is to study pain itself, resulting in unalleviated pain for many of the animals involved. Consequently, the use of animals in pain research is often considered contentious. To date, no research has explored people's views toward different types of animal-based pain research (e.g. chronic or acute pain). This study used a web-based survey to explore people's willingness to support the use of mice in chronic versus acute pain research. The majority of the participants opposed the use of mice for either chronic (68.3%) or acute (63.1%) pain research. There was no difference in the levels of support or opposition for chronic versus acute pain research. Unsupportive participants justified their opposition by focusing on the perceived lack of scientific merit, or the existence of non-animal alternatives. Supporters emphasised the potential benefits that could arise, with some stating that the benefits outweigh the costs. The majority of the participants were opposed to pain research involving mice, regardless of the nature and duration of the pain inflicted, or the perceived benefit of the research. A better understanding of public views toward animal use in pain research may provide a stronger foundation for the development of policy governing the use of animals in research where animals are likely to experience unalleviated pain.

Delayed-onset muscle soreness

Based on a thorough review of the available literature in the delayed-onset muscle soreness (DOMS) model, we identified multiple study design characteristics that are considered to be normative in acute pain research but have not been followed in a majority of published DOMS experiments. We designed an analgesic investigation using the DOMS model that both complied with current scientifically accepted standards for the conduct of analgesic studies and demonstrated reasonable assay sensitivity. This randomized, double-blind, placebo-controlled within-subject study compared the efficacy of topical diclofenac sodium 1% with a matching placebo in reducing pain associated with DOMS. After exercise, subjects reporting DOMS received topical diclofenac sodium gel 1% (DSG 1%) applied to one leg and placebo to the other every 6 hours for 48 hours. Pain intensity was assessed at rest, upon standing, and when walking in the 48 hours after initial drug application (T0). The primary end point was the reduction in pain intensity (SPID 24) on walking. Subjects receiving DSG 1% had less pain while walking compared with those receiving placebo at 24 hours (SPID 24 = 34.9 [22.9] and 23.6 [19.4], respectively; P = 0.032). This investigation used experimental techniques that have been vetted in the field of exercise physiology and superimposed techniques that are considered to be best practice in the field of analgesic research. Over time and with the help of colleagues in both fields of study, similar investigations will validate design features that impact the assay sensitivity of analgesic end points in DOMS models. In addition, the study confirmed the analgesic efficacy of topical DSG 1% over placebo in subjects experiencing DOMS.

The staying power of change: sustainability of pain practice improvements after a multidimensional knowledge translation intervention

Background Despite significant developments in acute pain research in hospitalized children, pain assessment and management practices for this population remain sub-optimal. To address the gap between research and practice a multidimensional, knowledge translation intervention, Evidence-based Practice for Improving Quality (EPIQ) [1] was successfully implemented at eight Canadian tertiary pediatric hospitals [2]. EPIQ was effective in improving pain practices immediately following the intervention completion in the EPIQ units compared to standard care (SC) [2]. However, the sustainability of these improvements requires consideration. The objective of this study is to determine the sustainability of the overall effect of EPIQ on pain practices 12 months post intervention.

Reply to Sarantopoulos and Fassoulaki, PAIN, 65 (1996) 273-276

Acute Pain Research Unit, The Toronto Hospital and Mount Sinai Hospital, The University of Toronto, Toronto, Ontario M5G 2C4, Canada PII S0304-3959(96)03264-2

Pain Control After Thoracic Surgery

Acute Pain Research Unit, Department of Anesthesia, and the Department of Psychology, The Toronto Hospital, Toronto General Division, and Department of Anesthesia and Department of Behavioral Science, University of Toronto, Toronto, Canada