The Acute to Chronic Pain Transition: Can Chronic Pain Be Prevented?

Postamputation Pain Management

Postamputation pain is one of the most common and challenging pain conditions to treat and includes residual limb pain and phantom limb pain. Residual limb pain is present at the amputation site or proximal to the amputation site and may be caused by poor wound healing, poor prosthetic fitting, or neuropathic pain. Phantom limb pain is experienced distal to the amputation site and may be caused by maladaptive supraspinal reorganization. Treatment for post amputation pain should be multimodal and multidisciplinary, including pharmacologic agents, rehabilitation, psychosocial support, and integrative therapies. Surgical interventions including neuromodulation may be considered for refractory cases.

Postsurgical Pain Risk Stratification to Enhance Pain Management Workflow in Adult Patients: Design, Implementation, and Pilot Evaluation

BACKGROUND

Exposure to opioids after surgery is the initial contact for some people who develop chronic opioid use disorder. Hence, effective postoperative pain management, with less reliance on opioids, is critical. The Perioperative Opioid Quality Improvement (POQI) program developed (1) a digital health platform leveraging patient-survey-reported risk factors and (2) a postsurgical pain risk stratification algorithm to personalize perioperative care by integrating several commercially available digital health solutions into a combined platform. Development was reduced in scope by the COVID-19 pandemic.

OBJECTIVE

This pilot study aims to assess the screening performance of the risk algorithm, quantify the use of the POQI platform, and evaluate clinicians' and patients' perceptions of its utility and benefit.

METHODS

A POQI platform prototype was implemented in a quality improvement initiative at a Canadian tertiary care center and evaluated from January to September 2022. After surgical booking, a preliminary risk stratification algorithm was applied to health history questionnaire responses. The estimated risk guided the patient assignment to a care pathway based on low or high risk for persistent pain and opioid use. Demographic, procedural, and medication administration data were extracted retrospectively from the electronic medical record. Postoperative inpatient opioid use of >90 morphine milligram equivalents per day was the outcome used to assess algorithm performance. Data were summarized and compared between the low- and high-risk groups. POQI use was assessed by completed surveys on postoperative days 7, 14, 30, 60, 90, and 120. Semistructured patient and clinician interviews provided qualitative feedback on the platform.

RESULTS

Overall, 276 eligible patients were admitted for colorectal procedures. The risk algorithm stratified 203 (73.6%) as the low-risk group and 73 (26.4%) as the high-risk group. Among the 214 (77.5%) patients with available data, high-risk patients were younger than low-risk patients (age: median 53, IQR 40-65 years, vs median 59, IQR 49-69 years, median difference five years, 95% CI 1-9; P=.02) and were more often female patients (45/73, 62% vs 80/203, 39.4%; odds ratio 2.5, 95% CI 1.4-4.5; P=.002). The risk stratification was reasonably specific (true negative rate=144/200, 72%) but not sensitive (true positive rate=10/31, 32%). Only 39.7% (85/214) patients completed any postoperative quality of recovery questionnaires (only 14, 6.5% patients beyond 60 days after surgery), and 22.9% (49/214) completed a postdischarge medication survey. Interviewed participants welcomed the initiative but noted usability issues and poor platform education.

CONCLUSIONS

An initial POQI platform prototype was deployed operationally; the risk algorithm had reasonable specificity but poor sensitivity. There was a significant loss to follow-up in postdischarge survey completion. Clinicians and patients appreciated the potential impact of preemptively addressing opioid exposure but expressed shortcomings in the platform's design and implementation. Iterative platform redesign with additional features and reevaluation are required before broader implementation.

The Effect of Everyday-Life Social Contact on Pain

Pain is a biopsychosocial phenomenon, resulting from the interplay between physiological and psychological processes and social factors. Given that humans constantly interact with others, the effect of social factors is particularly relevant. Documenting the significance of the social modulation of pain, an increasing number of studies have investigated the effect of social contact on subjective pain intensity and pain-related physiological changes. While evidence suggests that social contact can alleviate pain, contradictory findings indicate an increase in pain intensity and a deterioration of pain coping strategies. This evidence primarily stems from studies examining the effect of social contact on pain within highly controlled laboratory conditions. Moreover, pain assessments often rely on one-time subjective reports of average pain intensity across a predefined period. Ecological momentary assessments (EMAs) can circumvent these problems, as they can capture diverse aspects of behavior and experiences multiple times a day, in real time, with high resolution, and within naturalistic and ecologically valid settings. These multiple measures allow for the examination of fluctuations of pain symptoms throughout the day in relation to affective, cognitive, behavioral, and social factors. In this opinion paper, we review the current state and future relevance of EMA-based social pain research in daily life. Specifically, we examine whether everyday-life social support reduces or enhances pain. The first part of the paper provides a comprehensive overview of the use of EMA in pain research and summarizes the main findings. The review of the relatively limited number of existing EMA studies shows that the association between pain and social contact in everyday life depends on numerous factors, including pain syndromes, temporal dynamics, the nature of social interactions, and characteristics of the interaction partners. In line with laboratory research, there is evidence that everyday-life social contact can alleviate, but also intensify pain, depending on the type of social support. Everyday-life emotional support seems to reduce pain, while extensive solicitous support was found to have opposite effects. Moreover, positive short-term effects of social support can be overshadowed by other symptoms such as fatigue. Overall, gathering and integrating experiences from a patient's social environment can offer valuable insights. These insights can help interpret dynamics in pain intensity and accompanying symptoms such as depression or fatigue. We conclude that factors determining the reducing versus enhancing effects of social contact on pain need to be investigated more thoroughly. We advocate EMA as the assessment method of the future and highlight open questions that should be addressed in future EMA studies on pain and the potential of ecological momentary interventions for pain treatment.

Predictive analytics identifies key factors driving hyperalgesic priming of muscle sensory neurons

Hyperalgesic priming, a form of neuroplasticity induced by inflammatory mediators, in peripheral nociceptors enhances the magnitude and duration of action potential (AP) firing to future inflammatory events and can potentially lead to pain chronification. The mechanisms underlying the development of hyperalgesic priming are not well understood, limiting the identification of novel therapeutic strategies to combat chronic pain. In this study, we used a computational model to identify key proteins whose modifications caused priming of muscle nociceptors and made them hyperexcitable to a subsequent inflammatory event. First, we extended a previously validated model of mouse muscle nociceptor sensitization to incorporate Epac-mediated interaction between two G protein-coupled receptor signaling pathways commonly activated by inflammatory mediators. Next, we calibrated and validated the model simulations of the nociceptor's AP response to both innocuous and noxious levels of mechanical force after two subsequent inflammatory events using literature data. Then, by performing global sensitivity analyses that simulated thousands of nociceptor-priming scenarios, we identified five ion channels and two molecular processes (from the 18 modeled transmembrane proteins and 29 intracellular signaling components) as potential regulators of the increase in AP firing in response to mechanical forces. Finally, when we simulated specific neuroplastic modifications in Kv1.1 and Nav1.7 alone as well as with simultaneous modifications in Nav1.7, Nav1.8, TRPA1, and Kv7.2, we observed a considerable increase in the fold change in the number of triggered APs in primed nociceptors. These results suggest that altering the expression of Kv1.1 and Nav1.7 might regulate the neuronal hyperexcitability in primed mechanosensitive muscle nociceptors.

Postmastectomy Pain Syndrome: A Narrative Review

Postmastectomy pain syndrome is a very common disorder in breast cancer survivors. The impact on the quality of patients' lives is significantly adverse. The precise pathophysiology has not been determined as yet though various risk factors have been identified that make the patient vulnerable. Required preoperative work includes the identification and possible elimination of risk factors. Treatment is multidisciplinary involving surgical and non-surgical modalities. There is a great scope of research in this field.

Looking Back, Moving Forward in Pain Medicine

Pain is an ancient medical complaint and a clinical riddle that has never been entirely solved. Looking back into history was the springboard to a look into the future of pain medicine. This article was based on a series of presentations given in a recent congress (May 2023) and represents the research, views, and opinions of the authors. Opium has been used for millennia to treat pain, but when it gained broad use in the United States in the 1980s and 1990s, it was so vastly overprescribed and mis-prescribed that it led to a public health crisis. This, in turn, led to the reaction where opioids at times were under-prescribed, leaving out many patients who may have benefited from opioids while leaving many legacy pain patients to manage withdrawal on their own and with few analgesic options. Cannabinoids (CB) were likewise widely used for various conditions, including pain, but were outlawed in the 20th century, only to be brought back as a potential analgesic agent. Interventional pain medicine is a developing discipline and has reinforced the concept of the interdisciplinary pain clinic. It plays an increasingly important part in modern medicine overall, especially with the support of ultrasound, for both diagnosis and therapy. Today, the views about pain have changed. Anyone has accepted that pain is not purely a physical phenomenon but a biopsychosocial phenomenon that occurs within a cultural context. Pain management remains a small but vitally important medical subspecialty that is critical from a functional enablement and population health perspective, which is helping to navigate new therapeutic targets, new drugs and routes of administration, greater understanding of pain psychology, and new technologies. Pain control today means early intervention, functional enablement through pain alleviation, educating patients about pain management, and minimizing the transition from acute to chronic pain.

Thalamocortical Mechanisms Underlying Real and Imagined Acupuncture

Both acupuncture and imagery have shown potential for chronic pain management. However, the mechanisms underlying their analgesic effects remain unclear. This study aims to explore the thalamocortical mechanisms underlying acupuncture and video-guided acupuncture imagery treatment (VGAIT), a combination of acupuncture and guided imagery, using the resting-state functional connectivity (rsFC) of three thalamic subdivisions-the ventral posterolateral thalamus (VPL), mediodorsal thalamus (MD), and motor thalamus subregion (Mthal)-associated with somatosensory, limbic, and motor circuity. Twenty-seven healthy individuals participated in a within-subject randomized crossover design study. Results showed that compared to sham acupuncture, real acupuncture altered the rsFC between the thalamus and default mode network (DMN) (i.e., mPFC, PCC, and precuneus), as well as the prefrontal and somatosensory cortex (SI/SII). Compared to the VGAIT control, VGAIT demonstrated greater rsFC between the thalamus and key nodes within the interoceptive network (i.e., anterior insula, ACC, PFC, and SI/SII), as well as the motor and sensory cortices (i.e., M1, SMA, and temporal/occipital cortices). Furthermore, compared to real acupuncture, VGAIT demonstrated increased rsFC between the thalamus (VPL/MD/Mthal) and task-positive network (TPN). Further correlations between differences in rsFC and changes in the heat or pressure pain threshold were also observed. These findings suggest that both acupuncture- and VGAIT-induced analgesia are associated with thalamocortical networks. Elucidating the underlying mechanism of VGAIT and acupuncture may facilitate their development, particularly VGAIT, which may be used as a potential remote-delivered pain management approach.

Does Preoperative Hookwire Localization Influence Postoperative Acute and Chronic Pain After Video-Assisted Thoracoscopic Surgery: A Prospective Cohort Study

Purpose

This study aimed to investigate whether preoperative computerized tomography-guided hookwire localization-associated pain could affect acute and chronic postsurgical pain (CPSP) in patients undergoing video-assisted thoracoscopic surgery (VATS).

Methods

We enrolled 161 adult patients who underwent elective VATS; sixty-nine patients experienced hookwire localization (Group A) and 69 did not (Group B). Group A was further subdivided into the multiple localization group (n=35, Group A_multiple) and the single localization group (n=34, Group A_single) according to the number of hookwires. The numerical rating scale (NRS) was used preoperatively, during recovery at the post-anesthesia care unit (PACU), and the first two days, 3 and 6 months postoperatively. Furthermore, multivariate regression analysis was used to identify the risk factors associated with CPSP. The postoperative adverse events, length of hospital stay, and satisfaction in pain management were also recorded.

Results

The incidence and severity of acute postoperative pain were similar between Group A and Group B (p > 0.05). The incidence (56.5% vs 30.4%, p = 0.002) and the NRS scores (2.0 [2.0-3.0] vs 1.0 [1.0-2.0], p = 0.011) for CPSP were significantly higher in Group A than in Group B at 3 months postoperatively. On subgroup analysis, compared with Group A_single, the intensity of CPSP (2.0 [2.0-3.0] vs 2.0 [1.0-2.0], p = 0.005) in Group A_multiple was slightly higher at 3 months postoperatively. Conversely, the CPSP incidence (60.0% vs 29.4%, p = 0.011) was significantly higher at 6 months postoperatively in Group A_multiple. The multivariate regression analysis further validated hookwire localization as a risk factor for CPSP (odds ratio: 6.199, 95% confidence interval 2.049-18.749, p = 0.001). Patient satisfaction relating to pain management at 3 months postoperatively was lower in Group A (p = 0.034).

Conclusion

The preoperative pain stress of hookwire localization increased the incidence and intensity of CPSP rather than acute pain at 3 months postoperatively, especially in patients with multiple hookwires.

Biopsychosocial Approach in Identifying Risk Factors of Kinesiophobia in Persons with Subacromial Pain Syndrome and Developing a Clinical Prediction Tool

Introduction

Although the negative effects of kinesiophobia on functional status in subacromial pain syndrome (SAPS) patients are clearly demonstrated, no study examines the risk factors of kinesiophobia in individuals with SAPS from a biopsychosocial perspective. The present study aims to determine the risk factors of kinesiophobia in individuals with SAPS using a biopsychosocial approach. This study also aims to explore the compounding effects of multiple associative risk factors by developing a clinical prediction tool to identify SAPS patients at higher risk for kinesiophobia.

Materials and methods

This cross-sectional study included 549 patients who were diagnosed with SAPS. The Tampa-Scale of Kinesiophobia (TSK) was used to assess kinesiophobia. Visual analog scale (VAS), The Shoulder Pain and Disability Index (SPADI), Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire, the presence of metabolic syndrome, using any non-steroidal anti-inflammatory drugs, Pain Catastrophizing Scale (PCS), Illness Perception Questionnaire-revised (IPQ-R), Hospital Anxiety and Depression Scale (HADS), behavioral pattern of the patient, sociodemographic characteristics, and treatment expectancy were outcome measures.

Results

Thirteen significant risk factors of having kinesiophobia were: VASat rest (≥ 5.2), VASduring activity (≥ 7.1), DASH (≥ 72.1), presence of metabolic syndrome, PCShelplessness (≥ 16.1), IPQ-Rpersonal control (≤ 17.1), IPQ-Rtreatment control (≤ 16.3), HADSdepression (≥ 7.9), avoidance behavior type, being female, educational level (≤ high school), average hours of sleep (≤ 6.8), and treatment expectancy (≤ 6.6). The presence of seven or more risk factors increased the probability of having high level of kinesiophobia from 34.3 to 51%.

Conclusions

It seems necessary to address these factors, increase awareness of health practitioners and individuals.

Level of evidence

Level IV.

Targeting Affective Mood Disorders With Ketamine to Prevent Chronic Postsurgical Pain

The phencyclidine-derivative ketamine [2-(2-chlorophenyl)-2-(methylamino)cyclohexan-1-one] was added to the World Health Organization's Model List of Essential Medicines in 1985 and is also on the Model List of Essential Medicines for Children due to its efficacy and safety as an intravenous anesthetic. In sub-anesthetic doses, ketamine is an effective analgesic for the treatment of acute pain (such as may occur in the perioperative setting). Additionally, ketamine may have efficacy in relieving some forms of chronic pain. In 2019, Janssen Pharmaceuticals received regulatory-approval in both the United States and Europe for use of the S-enantiomer of ketamine in adults living with treatment-resistant major depressive disorder. Pre-existing anxiety/depression and the severity of postoperative pain are risk factors for development of chronic postsurgical pain. An important question is whether short-term administration of ketamine can prevent the conversion of acute postsurgical pain to chronic postsurgical pain. Here, we have reviewed ketamine's effects on the biopsychological processes underlying pain perception and affective mood disorders, focusing on non-NMDA receptor-mediated effects, with an emphasis on results from human trials where available.

Opioids and Public Health: The Prescription Opioid Ecosystem and Need for Improved Management

While U.S. opioid prescribing has decreased 38% in the past decade, opioid deaths have increased 300%. This opioid paradox is poorly recognized. Current approaches to opioid management are not working, and new approaches are needed. This article reviews the outcomes and shortcomings of recent U.S. opioid policies and strategies that focus primarily or exclusively on reducing or eliminating opioid prescribing. It introduces concepts of a prescription opioid ecosystem and opioid pool, and it discusses how the pool can be influenced by supply-side, demand-side, and opioid returns factors. It illuminates pressing policy needs for an opioid ecosystem that enables proper opioid stewardship, identifies associated responsibilities, and emphasizes the necessity of making opioid returns as easy and common as opioid prescribing, in order to minimize the size of the opioid pool available for potential diversion, misuse, overdose, and death. Approaches are applicable to opioid prescribing in general, and to opioid prescribing after surgery.

Acute Pain Service in Hungarian hospitals

Background

Surgical procedures play an increasing role among health technologies to treat diseases. Pain often accompanies such diseases, both as a result of their pathology, but also as the side-effect of the intervention itself, and it is not only a burdensome subjective feeling, but adversely affects the recovery process, can induce complications and increases treatment costs. Acute Pain Service Teams are becoming increasingly widespread in hospitals to address post-operative pain, yet we have so far no data on how many hospitals have actually adopted this technology in Hungary.

Objectives

The main objectives of our study were to assess the prevalence of Acute Pain Service Teams, map their structure and operation, as well as to understand the barriers and conducive factors of their establishment in Hungarian hospitals.

Methods

We carried out a survey among the 72 hospitals with surgical departments. The questionnaire was filled in by 52 providers, which gave us a response rate of 72.2%.

Results

Our results show, that only two of the responding hospitals have Acute Pain Service Teams albeit their structure and operation are in line with the literature. In the 50 hospitals without such teams, financing difficulties and human resources shortages are mentioned to be the most important obstacles of their establishment, but the lack of initiative and interest on the part of the specialities concerned are also an important barrier.

Conclusions

Lagging behind the more affluent EU member states, but similarly to other Central and Eastern European countries, Acute Pain Service has been hardly adopted by Hungarian hospitals. Hungarian health professionals know the technology and would support its wider introduction, if the technical feasibility barriers could be overcome. Health policy should play a more active role to facilitate change in this area, the investment in which promises a substantial return in terms of health gains and cost savings.

Electroacupuncture Regulates Pain Transition Through Inhibiting PKCε and TRPV1 Expression in Dorsal Root Ganglion

Many cases of acute pain can be resolved with few side effects. However, some cases of acute pain may persist beyond the time required for tissue injury recovery and transit to chronic pain, which is hard to treat. The mechanisms underlying pain transition are not entirely understood, and treatment strategies are lacking. In this study, the hyperalgesic priming model was established on rats to study pain transition by injection of carrageenan (Car) and prostaglandin E2 (PGE2). The expression levels of protein kinase C epsilon (PKCε) and transient receptor potential vanilloid 1 (TRPV1) in the L4–L6 dorsal root ganglion (DRG) were investigated. Electroacupuncture (EA) is a form of acupuncture in which a small electric current is passed between a pair of acupuncture needles. EA was administrated, and its effect on hyperalgesia and PKCε and TRPV1 expression was investigated. The PKCε–TRPV1 signaling pathway in DRG was implicated in the pain transition. EA increased the pain threshold of model animals and regulated the high expression of PKCε and TRPV1. Moreover, EA also regulated hyperalgesia and high TRPV1 expression induced by selective PKCε activation. We also found that EA partly increased chronic pain threshold, even though it was only administered between the Car and PGE2 injections. These findings suggested that EA could prevent the transition from acute to chronic pain by inhibiting the PKCε and TRPV1 expression in the peripheral nervous system.

Comparative evaluation of analgesic efficacy of buprenorphine transdermal patch and fentanyl patch in management of postoperative pain after arthroscopic lower limb surgery: A randomized controlled trial

Background and Aims

Transdermal opioids are newer modality in use for the control of postoperative pain, because of its noninvasiveness, longer duration of action, sustained blood levels, and with minimal side effects. The study was aimed to evaluate the efficacy of analgesia of buprenorphine patch 10, 20 μg·h^-1 and fentanyl patch 25 μg·h^-1 for relief of pain in the postoperative period in patients undergoing arthroscopic lower limb surgeries.

Materials and Methods

It was a randomized, double-blinded, prospective study in which adult patients undergoing lower limb arthroscopic surgery were randomly segregated into three groups. In Group 1 (fentanyl patch 25 μg·h^-1), Group 2 (buprenorphine patch 10 μg·h^-1), and Group 3 (buprenorphine patch 20 μg·h^-1), transdermal patches were applied 12 h prior to surgery. Mean NRS score, total rescue analgesic requirement, drug-related adverse effects, and hemodynamic status were evaluated till 72 h in the postoperative period.

Results

Out of 175 screened patients, 150 patients were finally analyzed. Baseline characteristics were the same among all the three groups. Median NRS score was lowest in Group 3 [P value < 0.05 at 2, 4, 8, 12, and 24 h after surgery (Kruskal Wallis test). The total consumption of postoperative rescue analgesic diclofenac was the lowest in Group 3 as compared to other groups without any significant increase in adverse events.

Conclusions

In arthroscopic lower limb surgery, buprenorphine patch (20 μg·h^-1) applied 12 h prior to surgery is an effective postoperative analgesic and it is not associated with any significant adverse effects.

Transitioning to chronic temporomandibular disorder pain: A combination of patient vulnerabilities and iatrogenesis

Background

Based on a variety of studies conducted in recent years, some of the factors that might contribute to the negative treatment responses of some TMD patients have been elucidated.

Methods

This paper describes known vulnerability factors that make individuals susceptible to developing temporomandibular disorders (TMDs), as well as those that contribute to the perpetuation of such problems. In addition, the topic of iatrogenesis is discussed as a major contributor to the negative outcomes that can be seen in this field.

Results

At the patient level, anatomical, psychosocial and genetic factors may contribute to individual vulnerability. The anatomy and pathophysiology of muscles, joints, disc and nerves may all be involved in predisposing to TMD symptoms, especially when the patients have pain elsewhere in the body. Among the psychosocial factors, some features may be elucidated by the DC/TMD axis II, while others (eg illness behaviour, Munchausen syndrome, lack of acceptance of non‐mechanical approaches) require careful evaluation by trained clinicians. Genetic predisposition to first onset TMDs and to chronification of symptoms has been identified for individuals with certain psychological traits, presence of comorbid conditions and certain abnormal clinical manifestations. Regarding iatrogenesis, sins of omission may influence the clinical picture, with the main ones being misdiagnosis and undertreatment. Joint repositioning strategies, occlusal modifications, abuse of oral appliances, use of diagnostic technologies, nocebo effect and complications with intracapsular treatments are the most frequent sins of commission that may contribute to chronification of TMDs. The patients who present with massive occlusal and jaw repositioning changes combined with persistent severe orofacial pain are not a rarity within TMD and orofacial pain canters; these patients are the most difficult ones to manage because of this horrific combination of negative factors.

Conclusions

The information presented in this paper will help clinicians to understand better why some individuals develop temporomandibular disorders, why some of them will progress to becoming chronic patients, and what the appropriate responses may be.

Oliceridine for the Management of Acute Postoperative Pain

OBJECTIVE

To review the pharmacological characteristics, clinical evidence, and place in the management of acute postoperative pain severe enough to require an intravenous opioid.

DATA SOURCES

A comprehensive literature search was conducted in PubMed (January 2000 to December 1, 2020). Key search terms included oliceridine or acute postoperative pain. Other sources were derived from product labeling and ClinicalTrials.gov.

STUDY SELECTION AND DATA EXTRACTION

All English-language articles identified from the data sources were reviewed and evaluated. Phase I, II, and III clinical trials were included.

DATA SYNTHESIS

Oliceridine is a novel selective µ-receptor G-protein pathway modulator. It has the property of activating G-protein signaling while causing low β-arrestin recruitment to the µ-receptor. Intravenous oliceridine showed statistically superior analgesia than placebo in patients with moderate or severe pain after surgery, with a favorable safety and tolerability profile regarding respiratory and gastrointestinal adverse effects, compared with morphine.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

The analgesic capacity of oliceridine is at least comparable to that of morphine at clinically relevant dosages, with a rapid onset of action. Also, it may be associated with a lower incidence of adverse events at dosing regimens associated with comparable analgesia. These data suggest that oliceridine may provide an important new treatment option for the management of moderate to severe postoperative pain where an intravenous opioid is warranted.

CONCLUSION

Oliceridine has obvious analgesic effects in patients with moderate or severe pain after surgery; additionally, it has a favorable safety and tolerability profile.

Wearable Devices: Current Status and Opportunities in Pain Assessment and Management

INTRODUCTION

We investigated the possibilities and opportunities for using wearable devices that measure physical activity and physiometric signals in conjunction with ecological momentary assessment (EMA) data to improve the assessment and treatment of pain.

METHODS

We considered studies with cross-sectional and longitudinal designs as well as interventional or observational studies correlating pain scores with measures derived from wearable devices. A search was also performed on studies that investigated physical activity and physiometric signals among patients with pain.

RESULTS

Few studies have assessed the possibility of incorporating wearable devices as objective tools for contextualizing pain and physical function in free-living environments. Of the studies that have been conducted, most focus solely on physical activity and functional outcomes as measured by a wearable accelerometer. Several studies report promising correlations between pain scores and signals derived from wearable devices, objectively measured physical activity, and physical function. In addition, there is a known association between physiologic signals that can be measured by wearable devices and pain, though studies using wearable devices to measure these signals and associate them with pain in free-living environments are limited.

CONCLUSION

There exists a great opportunity to study the complex interplay between physiometric signals, physical function, and pain in a real-time fashion in free-living environments. The literature supports the hypothesis that wearable devices can be used to develop reproducible biosignals that correlate with pain. The combination of wearable devices and EMA will likely lead to the development of clinically meaningful endpoints that will transform how we understand and treat pain patients.

Ketamine normalizes high-gamma power in the anterior cingulate cortex in a rat chronic pain model

Chronic pain alters cortical and subcortical plasticity, causing enhanced sensory and affective responses to peripheral nociceptive inputs. Previous studies have shown that ketamine had the potential to inhibit abnormally amplified affective responses of single neurons by suppressing hyperactivity in the anterior cingulate cortex (ACC). However, the mechanism of this enduring effect has yet to be understood at the network level. In this study, we recorded local field potentials from the ACC of freely moving rats. Animals were injected with complete Freund’s adjuvant (CFA) to induce persistent inflammatory pain. Mechanical stimulations were administered to the hind paw before and after CFA administration. We found a significant increase in the high-gamma band (60–100 Hz) power in response to evoked pain after CFA treatment. Ketamine, however, reduced the high-gamma band power in response to evoked pain in CFA-treated rats. In addition, ketamine had a sustained effect on the high-gamma band power lasting up to five days after a single dose administration. These results demonstrate that ketamine has the potential to alter maladaptive neural responses in the ACC induced by chronic pain.

Postoperative Pain, Narcotics Consumption, and Patient-Reported Outcomes Based on PROMIS Physical Function Following a Single-Level Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Retrospective.

OBJECTIVE

To determine the association between preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) scores with postoperative pain, narcotics use, and patient-reported outcomes (PRO) following a single-level anterior cervical discectomy and fusion (ACDF) procedure.

SUMMARY OF BACKGROUND DATA

There is a scarcity of prior literature on the ability of baseline PROMIS scores to predict clinical outcomes for patients undergoing ACDF procedures.

METHODS

Patients who underwent a primary ACDF were retrospectively reviewed and stratified into low and high disability cohorts. Preoperative PROMIS PF cohorts were tested for association with demographic and perioperative characteristics using chi-square analysis and one-way analysis of variance. Cohorts were tested for association with inpatient pain scores and narcotics consumption, as well as postoperative improvements in PROMIS PF, neck disability index (NDI), and visual analog scale (VAS) neck and arm pain using linear regression.

RESULTS

Ninety one patients were included: 39 low disability and 52 high disability. Inpatient postoperative VAS pain scores and narcotic consumption are also compared between cohorts. Patients with greater disability reported higher VAS pain scores (P = 0.003). However, patients in both cohorts consumed comparable amounts of narcotics (P = 0.926). Patients with greater preoperative disability demonstrated lower PROMIS PF scores, greater NDI scores, and greater VAS Neck scores at the preoperative baseline. However, patients demonstrated similar improvement of VAS neck and arm pain, as well as NDI at all postoperative timepoints. Patients with low disability reported worsened physical function at the 6 weeks timepoint.

CONCLUSION

Patients with worse preoperative disability as measured by PROMIS PF reported increased pain but comparable narcotics consumption in the immediate postoperative period following a single-level ACDF procedure. Furthermore, patients experienced similar long-term postoperative improvement of PROs regardless of preoperative physical function. PROMIS PF can efficiently quantify physical function before and after the ACDF procedure as self-evaluated by patients.

LEVEL OF EVIDENCE

3.

Developments in combined analgesic regimens for improved safety in postoperative pain management

Introduction: Fixed-dose combination analgesic regimens may be similarly effective to opioid monotherapy but with potentially less risk. A number of individualized combination regimens can be created, including nonopioid agents such as acetaminophen and nonsteroidal anti-inflammatory drugs, opioids, and adjunctive agents such as gabapentin, pregabalin, and muscle relaxants. Areas covered: When such combinations have a synergistic effect, analgesic benefits may be enhanced. Many combination analgesic regimens are opioid sparing, which sometimes but not always results in reduced opioid-associated side effects. Safety concerns for all analgesics must be considered but postoperative analgesia is typically administered for a brief period (days), reducing risks that may occur with prolonged exposure. Expert opinion: Judiciously considered combination analgesic regimens can be effective postoperative analgesics that reduce opioid consumption without compromising pain control, which are important factors for patient recovery and satisfaction. The specific combinations used must be based on the patient, the type and duration of the surgical procedure, and complementary mechanisms of action of the agents used. In opioid-sparing combination analgesic regimens, the short-term use of small doses of opioids in this setting may be helpful for appropriate patients.

Electroacupuncture Regulates Pain Transition by Inhibiting the mGluR5-PKCε Signaling Pathway in the Dorsal Root Ganglia

Background

Acute pain can transition to chronic pain, presenting a major clinical challenge. Electroacupuncture (EA) can partly prevent the transition from acute to chronic pain. However, little is known about the mechanisms underlying the effect of EA. This study investigated the effect of EA on pain transition and the activation of metabotropic glutamate receptor 5 (mGluR5)–protein kinase C epsilon (PKCε) signaling pathway in the dorsal root ganglia (DRG).

Methods

The hyperalgesic priming model was established by the sequential intraplantar injection of carrageenan (1%, 100 μL) and prostaglandin E2 (PGE2) into the left hind paw of rats. EA treatment (2/100 Hz, 30 min, once/day) was applied at bilateral Zusanli (ST36) and Kunlun (BL60) acupoints in rats. Von Frey filaments were used to investigate the mechanical withdrawal threshold (MWT) at different time points. The protein expression levels of mGluR5 and PKCε in the ipsilateral L4-L6 DRGs of rats were detected by Western blot. Some pharmacological experiments were performed to evaluate the relationship between mGluR5, PKCε and the MWT. It was also used to test the effects of EA on the expression levels of mGluR5 and PKCε and changes in the MWT.

Results

Sequential injection of carrageenan and PGE2 significantly decreased the MWT of rats and up-regulated the expression level of mGluR5 and PKCε in the ipsilateral L4-L6 DRGs. EA can reverse the hyperalgesic priming induced by sequential injection of carrageenan/PGE and down-regulate the protein expression of mGluR5 and PKCε. Glutamate injection instead of PGE2 can mimic the hyperalgesic priming model. Pharmacological blocking of mGluR5 with specific antagonist MTEP can prevent the hyperalgesic priming and inhibit the activation of PKCε in DRGs. Furthermore, EA also produced analgesic effect on the hyperalgesic priming rats induced by carrageenan/mGluR5 injection and inhibited the high expression of PKCε. Sham EA produced none analgesic and regulatory effect.

Conclusion

EA can regulate pain transition and it may relate with its inhibitory effect on the activation of mGluR5-PKCε signaling pathway in the DRGs.

Patient-Controlled Intravenous Morphine Analgesia Combined with Transcranial Direct Current Stimulation for Post-Thoracotomy Pain: A Cost-Effectiveness Study and A Feasibility For Its Future Implementation

This prospective randomized study aims to evaluate the feasibility and cost-effectiveness of combining transcranial direct current stimulation (tDCS) with patient controlled intravenous morphine analgesia (PCA-IV) as part of multimodal analgesia after thoracotomy. Patients assigned to the active treatment group (a-tDCS, n = 27) received tDCS over the left primary motor cortex for five days, whereas patients assigned to the control group (sham-tDCS, n = 28) received sham tDCS stimulations. All patients received postoperative PCA-IV morphine. For cost-effectiveness analysis we used data about total amount of PCA-IV morphine and maximum visual analog pain scale with cough (VASP-C_max). Direct costs of hospitalization were assumed as equal for both groups. Cost-effectiveness analysis was performed with the incremental cost-effectiveness ratio (ICER), expressed as the incremental cost (RSD or US$) per incremental gain in mm of VASP-C_max reduction. Calculated ICER was 510.87 RSD per VASP-C_max 1 mm reduction. Conversion on USA market (USA data 1.325 US$ for 1 mg of morphine) revealed ICER of 189.08 US$ or 18960.39 RSD/1 VASP-C_max 1 mm reduction. Cost-effectiveness expressed through ICER showed significant reduction of PCA-IV morphine costs in the tDCS group. Further investigation of tDCS benefits with regards to reduction of postoperative pain treatment costs should also include the long-term benefits of reduced morphine use.

Pain management in trauma patients affected by the opioid epidemic: A narrative review

Acute and chronic pain in trauma patients remains a challenging entity, particularly in the setting of the escalating opioid epidemic. It has been reported that chronic opioid use increases the likelihood of hospital admissions as a result of traumatic injuries. Furthermore, patients admitted with traumatic injuries have a greater than average risk of developing opioid use disorder after discharge. Practitioners providing care to these patients will encounter the issue of balancing analgesic goals and acute opioid withdrawal with the challenge of reducing postdischarge persistent opioid use. Additionally, the practitioner is faced with the worrisome prospect that inadequate treatment of acute pain may lead to the development of chronic pain and overtreatment may result in opioid dependence. It is therefore imperative to understand and execute alternative nonopioid strategies to maximize the benefits and reduce the risks of analgesic regimens in this patient population. This narrative review will analyze the current literature on pain management in trauma patients and highlight the application of the multimodal approach in potentially reducing the risks of both short- and long-term opioid use. LEVEL OF EVIDENCE: Narrative review, moderate to High.

Intraoperative Methadone in Same-Day Ambulatory Surgery: A Randomized, Double-Blinded, Dose-Finding Pilot Study

BACKGROUND

Approximately 50 million US patients undergo ambulatory surgery annually. Postoperative opioid overprescribing is problematic, yet many patients report inadequate pain relief. In major inpatient surgery, intraoperative single-dose methadone produces better analgesia and reduces opioid use compared with conventional repeated dosing of short-duration opioids. This investigation tested the hypothesis that in same-day ambulatory surgery, intraoperative methadone, compared with short-duration opioids, reduces opioid consumption and pain, and determined an effective intraoperative induction dose of methadone for same-day ambulatory surgery.

METHODS

A double-blind, dose-escalation protocol randomized 60 patients (2:1) to intraoperative single-dose intravenous methadone (initially 0.1 then 0.15 mg/kg ideal body weight) or conventional as-needed dosing of short-duration opioids (eg, fentanyl, hydromorphone; controls). Intraoperative and postoperative opioid consumption, pain, and opioid side effects were assessed before discharge. Patient home diaries recorded pain, opioid use, and opioid side effects daily for 30 days postoperatively. Primary outcome was in-hospital (intraoperative and postoperative) opioid use. Secondary outcomes were 30 days opioid consumption, pain intensity, and opioid side effects.

RESULTS

Median (interquartile range) methadone doses were 6 (5-6) and 9 (8-9) mg in the 0.1 and 0.15 mg/kg methadone groups, respectively. Total opioid consumption (morphine equivalents) in the postanesthesia care unit was significantly less compared with controls (9.3 mg, 1.3-11.0) in subjects receiving 0.15 mg/kg methadone (0.1 mg, 0.1-3.3; P < .001) but not 0.1 mg/kg methadone (5.0 mg, 3.3-8.1; P = .60). Dose-escalation ended at 0.15 mg/kg methadone. Total in-hospital nonmethadone opioid use after short-duration opioid, 0.1 mg/kg methadone, and 0.15 mg/kg methadone was 35.3 (25.0-44.0), 7.1 (3.7-10.0), and 3.3 (0.1-5.8) mg morphine equivalents, respectively (P < .001 for both versus control). In-hospital pain scores and side effects were not different between groups. In the 30 days after discharge, patients who received methadone 0.15 mg/kg had less pain at rest (P = .02) and used fewer opioid pills than controls (P < .0001), whereas patients who received 0.1 mg/kg had no difference in pain at rest (P = .69) and opioid use compared to controls (P = .08).

CONCLUSIONS

In same-day discharge surgery, this pilot study identified a single intraoperative dose of methadone (0.15 mg/kg ideal body weight), which decreased intraoperative and postoperative opioid requirements and postoperative pain, compared with conventional intermittent short-duration opioids, with similar side effects.

Poor preoperative sleep quality is a risk factor for severe postoperative pain after breast cancer surgery: A prospective cohort study

The aim of this study was to assess the effect of preoperative sleep quality on acute postoperative pain in breast cancer patients.The Pittsburgh Sleep Quality Index questionnaire (PSQI) was used to assess the overall sleep status of women scheduled for unilateral modified radical mastectomy in the past month. Based on the responses, patients were allocated to good sleep group or poor sleep group. Postoperatively, acute pain was assessed using the numerical rating score in the first 24 hours; in addition, the requirement of analgesics and the incidence of postoperative complications were recorded.A total of 108 breast surgery patients were enrolled. Based on the PSQI results, 55 (51%) patients were allocated to poor sleep group and 53 (49%) to good sleep group. Pain scores were similar in the 2 groups at the end of surgery (P = .589); however, poor sleep group reported higher postoperative pain scores than the good sleep group at 2 (P = .002), 6 (P < .001), 12 (P < .001), and 24 (P = .002) hours after surgery. The incidence of severe pain in the poor sleep group was higher than that in the good sleep group (27% vs 8%, P = .018), and the ratio of participants who required rescued analgesics was greater in the poor sleep group (52% vs 22%, P = .002). In addition, patients with poor sleep quality had more postoperative complications and longer hospital stay.In this study, breast cancer patients with poor preoperative sleep quality reported more severe postoperative pain, required more analgesics, experienced more complications, and had longer hospital stay.

Prospective cohort study examining the use of regional anesthesia for early pain management after combat-related extremity injury

BACKGROUND

No studies have examined the long-term benefits of regional anesthesia (RA) for pain management after combat-related injury. The objective of this prospective cohort study was to examine the relationship between RA administration and patient-reported pain-related outcomes among Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) service members sustaining a combat-related extremity injury.

METHODS

Between 2007 and 2013, n=358 American military personnel injured in OEF/OIF were enrolled at two military treatment facilities. Individuals were followed for up to 2 years after injury. Cohorts were defined based on whether participants were administered RA within 7 days after sustaining a combat-related injury, or not. Linear mixed effects models examined the association between RA and average pain intensity. Secondary outcomes included pain relief, pain interference, neuropathic pain symptoms, treatment outcomes related to pain management, and mental health symptoms.

RESULTS

Receiving early RA was associated with improved average pain over the first 6 months after injury (β=-0.57; p=0.012) adjusting for injury severity and length of stay at the primary treatment facility. This difference was observed up to 24 months after injury (β=-0.36; p=0.046). Individuals receiving early RA reported greater pain relief, improved neuropathic pain intensity, and higher satisfaction with pain outcomes; however, by 24 months, mean scores did not significantly differ between cohorts.

CONCLUSION

Findings indicate that when administered soon after traumatic injury, RA is a valuable pain management intervention. Future longitudinal studies investigating the timely delivery of RA for optimal pain management in civilian trauma settings are needed.

TRIAL REGISTRATION NUMBER

NCT00431847.

Multimodal analgesia in pain management after spine surgery

Multimodal analgesia (MMA) is the simultaneous use of multiple analgesic medications that work in a synergistic manner to provide pain control. In recent years, spine surgery has seen the growth of multimodal perioperative protocols for managing pain. Postoperative pain following spinal procedures is a common complaint, with persistent pain even after the immediate convalescent period leading to negative impacts on health. A multidisciplinary approach is essential in reducing postoperative morbidity and complication rates. This review demonstrates the efficacy in the combined use of opioid-alternative medications such as NSAIDs, gabapentinoids, local anesthetics, acetaminophen, and other neuromodulatory pharmacologic agents. Continued research will be essential in the optimization of the MMA protocol for treating patients who undergo spine procedures.

Management of postoperative pain in maxillofacial surgery

In this review we describe the evidence base for postoperative analgesia after maxillofacial surgery. We discuss the implications of poorly managed pain, risk factors for the development of severe pain, and pharmacological and non-pharmacological analgesic strategies to manage it.

Effects of Ketamine on Postoperative Pain After Remifentanil-Based Anesthesia for Major and Minor Surgery in Adults: A Systematic Review and Meta-Analysis

Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has been postulated as an adjuvant analgesic for preventing remifentanil-induced hyperalgesia after surgery. This systematic review and meta-analysis aims to assess the effectiveness of ketamine [racemic mixture and S-(+)-ketamine] in reducing morphine consumption and pain intensity scores after remifentanil-based general anesthesia. We performed a literature search of the PubMed, Web of Science, Scopus, Cochrane, and EMBASE databases in June 2017 and selected randomized controlled trials using predefined inclusion and exclusion criteria. To minimize confounding and heterogeneity, studies of NMDA receptor antagonists other than ketamine were excluded and the selected studies were grouped into those assessing minor or major surgery. Methodological quality was evaluated with the PEDro and JADA scales. The data were extracted and meta-analyses were performed where possible. Twelve RCTs involving 156 adults who underwent minor surgery and 413 adults who underwent major surgery were included in the meta-analysis. When used as an adjuvant to morphine, ketamine reduced postoperative morphine consumption in the first 24 h and postoperative pain intensity in the first 2 h in the minor and major surgery groups. It was also associated with significantly reduced pain intensity in the first 24 h in the minor surgery group. Time to the first rescue analgesia was longer in patients who received ketamine and underwent major surgery. No significant differences in the incidence of ketamine-related adverse effects were observed among patients in the intervention group and controls. This systematic review and meta-analysis show that low-dose (≤0.5 mg/kg for iv bolus or ≤5 μg/kg/min for iv perfusion) of ketamine reduces postoperative morphine consumption and pain intensity without increasing the incidence of adverse effects.

Pain chronification: what should a non-pain medicine specialist know?

OBJECTIVE

Pain is one of the most common reasons for an individual to consult their primary care physician, with most chronic pain being treated in the primary care setting. However, many primary care physicians/non-pain medicine specialists lack enough awareness, education and skills to manage pain patients appropriately, and there is currently no clear, common consensus/formal definition of "pain chronification".

METHODS

This article, based on an international Change Pain Chronic Advisory Board meeting which was held in Wiesbaden, Germany, in October 2016, provides primary care physicians/non-pain medicine specialists with a narrative overview of pain chronification, including underlying physiological and psychosocial processes, predictive factors for pain chronification, a brief summary of preventive strategies, and the role of primary care physicians and non-pain medicine specialists in the holistic management of pain chronification.

RESULTS

Based on currently available evidence, we propose the following consensus-based definition of pain chronification which provides a common framework to raise awareness among non-pain medicine specialists: "Pain chronification describes the process of transient pain progressing into persistent pain; pain processing changes as a result of an imbalance between pain amplification and pain inhibition; genetic, environmental and biopsychosocial factors determine the risk, the degree, and time-course of chronification."

CONCLUSIONS

Early intervention plays an important role in preventing pain chronification and, as key influencers in the management of patients with acute pain, it is critical that primary care physicians are equipped with the necessary awareness, education and skills to manage pain patients appropriately.

Comprehensive Acute Pain Management in the Perioperative Surgical Home

The careful coordination of care throughout the perioperative continuum offered by the perioperative surgical home (PSH) is important in the treatment of postoperative pain. Physician anesthesiologists have expertise in acute pain management, pharmacology, and regional and neuraxial anesthetic techniques, making them ideal leaders for managing perioperative analgesia within the PSH. Severe postoperative pain is one of many patient- and surgery-specific factors in the development of chronic postsurgical pain. Delivering adequate perioperative analgesia is important to avoid this development, to decrease perioperative morbidity, and to improve patient satisfaction.

Postoperative pain management in the postanesthesia care unit: an update

Acute postoperative pain remains a major problem, resulting in multiple undesirable outcomes if inadequately controlled. Most surgical patients spend their immediate postoperative period in the postanesthesia care unit (PACU), where pain management, being unsatisfactory and requiring improvements, affects further recovery. Recent studies on postoperative pain management in the PACU were reviewed for the advances in assessments and treatments. More objective assessments of pain being independent of patients' participation may be potentially appropriate in the PACU, including photoplethysmography-derived parameters, analgesia nociception index, skin conductance, and pupillometry, although further studies are needed to confirm their utilities. Multimodal analgesia with different analgesics and techniques has been widely used. With theoretical basis of preventing central sensitization, preventive analgesia is increasingly common. New opioids are being developed with minimization of adverse effects of traditional opioids. More intravenous nonopioid analgesics and adjuncts (such as dexmedetomidine and dexamethasone) are introduced for their opioid-sparing effects. Current evidence suggests that regional analgesic techniques are effective in the reduction of pain and stay in the PACU. Being available alternatives to epidural analgesia, perineural techniques and infiltrative techniques including wound infiltration, transversus abdominis plane block, local infiltration analgesia, and intraperitoneal administration have played a more important role for their effectiveness and safety.

Chronic post-amputation pain: peri-operative management - Review

Study design

Narrative review.

Method

Eight bibliographic databases were searched for studies published in the (last five years up until Feb 2017). For the two database searches (Cochrane and DARE), the time frame was unlimited. The review involved keyword searches of the term 'Amputation' AND 'chronic pain'. Studies selected were interrogated for any association between peri-operative factors and the occurrence of chronic post amputation pain (CPAP).

Results

Heterogeneity of study populations and outcome measures prevented a systematic review and hence a narrative synthesis of results was undertaken. The presence of variation in two gene alleles (GCH1 and KCNS1) may be relevant for development of CPAP. There was little evidence to draw conclusions on the association between age, gender and CPAP. Pre-operative anxiety and depression influenced pain intensity post operatively and long-term post amputation pain (CPAP). The presence of pre-amputation pain is correlated to the development of acute and chronic post amputation pain while evidence for the association of post-operative pain with CPAP is modest. Regional anaesthesia and peri-neural catheters improve acute postoperative pain relief but evidence on their efficacy to prevent CPAP is limited. A suggested whole system pathway based on current evidence to optimize peri-operative amputation pain is described.

Conclusion

The current evidence suggests that optimized peri-operative analgesia reduces the incidence of acute peri-operative pain but no firm conclusion can be drawn on reducing risk for CPAP.

A New Pain Regulatory System via the Brain Long Chain Fatty Acid Receptor GPR40/FFA1 Signal

An increasingly large number of pharmacological and physiological works on fatty acids have shown that the functional properties of fatty acids are regulated by the amount of individual fatty acid intake and the distribution of fatty acids among organs. Recently, it has been determined that G-protein-coupled receptor 40/free fatty acid receptor 1 (GPR40/FFA1) is activated by long-chain fatty acids, such as docosahexaenoic acid (DHA). GPR40/FFA1 is mainly expressed in the β cell of the pancreas, spinal cord and brain. It is reported that this receptor has a functional role in controlling blood glucose levels via the modulation of insulin secretion. However, its physiological function in the brain remains unknown. Our previous studies have shown that GPR40/FFA1 is expressed in pro-opiomelanocortin (POMC)-positive neurons of the arcuate nucleus, serotonergic neurons in the nucleus raphe magnus, and in noradrenergic neurons in the locus coeruleus. Furthermore, the intracerebroventricular injection of DHA or GW9508, which is a selective GPR40/FFA1 agonist, attenuates formalin-induced inflammatory pain behavior through increasing β-endorphin release in the hypothalamus. It also suppresses complete Freund's adjuvant-induced mechanical allodynia and thermal hyperalgesia. Our findings suggest that brain free long-chain fatty acids-GPR40/FFA1 signaling might have an important role in the modulation of endogenous pain control systems. In this review, I discuss the current status and our recent study regarding a new pain regulatory system via the brain long chain fatty acid receptor GPR40/FFA1 signal.

Assessing and Managing Acute Pain: A Call to Action

: Acute pain, which is usually sudden in onset and time limited, serves a biological protective function, warning the body of impending danger. However, while acute pain often resolves over time with normal healing, unrelieved acute pain can disrupt activities of daily living and transition to chronic pain. This article describes the effects of unrelieved acute pain on patients and clinical outcomes. The authors call on nurses to assess and manage acute pain in accordance with evidence-based guidelines, expert consensus reports, and position statements from professional nursing organizations in order to minimize the likelihood of its becoming chronic.

Research in Review: Advancing Critical Care Practice

Research published in 2016 identified strategies to enhance acute and critical care, initiated discussions on professional roles and responsibilities, clarified complex care issues, and led to robust debate. Some of this important work addressed strategies to prevent delirium and pressure ulcers, considerations for pain management within the context of the opioid abuse crisis, strategies to guide fluid resuscitation in patients with sepsis and heart failure, and ways to enhance care for family members of intensive care patients. The new sepsis definitions highlight the importance of detecting and providing care to patients with sepsis outside of critical care areas. Chimeric antigen receptor T-cell therapy is an example of the advancement of research in genomics and personalized medicine and of the need to understand the care implications of these therapies. Other research topics include interprofessional collaboration and shared decision-making as well as nurses' role in family conferences. Resources such as policies related to medical futility and inappropriate care and the American Association of Critical-Care Nurses' healthy work environment standards may inform conversations and provide strategies to address these complex issues.

The Cold Pressor Test as a Predictor of Prolonged Postoperative Pain, a Prospective Cohort Study

INTRODUCTION

Presently, it is difficult to predict which patients are at increased risk of ongoing pain problems postoperatively. This study followed a group of patients from the week before their operation until 3 months after it, to identify potential risk variables.

METHODS

Fifty-four patients undergoing moderate-major gynaecological surgery at Christchurch Women's Hospital were recruited and assessed preoperatively over an 11-week period. At this initial assessment, participants were subjected to a cold pressor test (CPT). Telephonic follow-up was conducted at 6 weeks and 3 months postoperatively, to determine pain status. Information regarding the type of operation and surgical approach was collected from hospital records.

RESULTS

Pain threshold (time taken to report the onset of pain), as measured by the CPT, was significantly predictive of prolonged pain outcomes (area under the curve = 0.80, 95 % CI 0.66, 0.95). Pain tolerance (total time taken to end the CPT voluntarily) was similarly predictive but non-significant (area under the curve = 0.69, 95 % CI 0.47, 0.90).

CONCLUSION

The preoperative cold pressor test shows some promise for predicting ongoing postoperative pain. However, more research is needed to determine the clinical significance of these findings in larger samples and how they could be incorporated into clinical practice.

Bedside diagnosis of persistent post-sternotomy pain

BACKGROUND

The prevalence of persistent post-sternotomy pain (PPSP) varies largely and has been mainly studied using questionnaires. We decided to perform a systematic qualitative and quantitative sensory examination study on a power-calculated sample of patients who had undergone sternotomy for cardiac surgery. Pain was diagnosed as PPSP if the patient complained of sternal pain that had developed after surgery together with corresponding sensory disturbances.

PATIENTS AND METHODS

One hundred elective patients undergoing coronary artery bypass via sternotomy were recruited for dynamic sensory mapping 4-6 months after surgery. Sensory testing was performed using thermal rollers, a cotton stick and pinprick. The intensity of sensation was registered as a score on a numeric rating scale. The area of sensory dysfunction on the chest wall was traced onto paper and calculated with the help of a computer-based program. The patient also answered a validated pain questionnaire.

RESULTS

Altogether 90 patients took part in the examination. Thirteen (15.4%) of the patients had pain and formed the PPSP group, while the remaining patients formed the non-PPSP group. Both groups had sensory abnormalities over the chest wall (69% of all patients). Sensory disturbances were more common, more profound and extended over a larger skin area in the PPSP group. Furthermore, daily activity performance in the PPSP group was poorer compared to the non-PPSP group.

CONCLUSION

PPSP is a clinical diagnosis easily achieved using simple diagnostic tools and a medical history. Severity and extent of sensory abnormalities were found to be greater in the PPSP group.