Pregabalin in severe burn injury pain: A double-blind, randomised placebo-controlled trial

Interventions for postburn pruritus

BACKGROUND

Postburn pruritus (itch) is a common and distressing symptom experienced on healing or healed burn or donor site wounds. Topical, systemic, and physical treatments are available to control postburn pruritus; however, it remains unclear how effective these are.

OBJECTIVES

To assess the effects of interventions for treating postburn pruritus in any care setting.

SEARCH METHODS

In September 2022, we searched the Cochrane Wounds Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE (including In-Process & Other Non-Indexed Citations), Ovid Embase, and EBSCO CINAHL Plus. We also searched clinical trials registries and scanned references of relevant publications to identify eligible trials. There were no restrictions with respect to language, publication date, or study setting.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that enrolled people with postburn pruritus to compare an intervention for postburn pruritus with any other intervention, placebo or sham intervention, or no intervention.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. We used GRADE to assess the certainty of the evidence.

MAIN RESULTS

We included 25 RCTs assessing 21 interventions with 1166 randomised participants. These 21 interventions can be grouped into six categories: neuromodulatory agents (such as doxepin, gabapentin, pregabalin, ondansetron), topical therapies (such as CQ-01 hydrogel, silicone gel, enalapril ointment, Provase moisturiser, beeswax and herbal oil cream), physical modalities (such as massage therapy, therapeutic touch, extracorporeal shock wave therapy, enhanced education about silicone gel sheeting), laser scar revision (pulsed dye laser, pulsed high-intensity laser, fractional CO2 laser), electrical stimulation (transcutaneous electrical nerve stimulation, transcranial direct current stimulation), and other therapies (cetirizine/cimetidine combination, lemon balm tea). Most RCTs were conducted at academic hospitals and were at a high risk of performance, attrition, and detection bias. While 24 out of 25 included studies reported change in burn-related pruritus, secondary outcomes such as cost-effectiveness, pain, patient perception, wound healing, and participant health-related quality of life were not reported or were reported incompletely. Neuromodulatory agents versus antihistamines or placebo There is low-certainty evidence that doxepin cream may reduce burn-related pruritus compared with oral antihistamine (mean difference (MD) -2.60 on a 0 to 10 visual analogue scale (VAS), 95% confidence interval (CI) -3.79 to -1.42; 2 studies, 49 participants). A change of 2 points represents a minimal clinically important difference (MCID). Due to very low-certainty evidence, it is uncertain whether doxepin cream impacts the incidence of somnolence as an adverse event compared to oral antihistamine (risk ratio (RR) 0.64, 95% CI 0.32 to 1.25; 1 study, 24 participants). No data were reported on pain in the included study. There is low-certainty evidence that gabapentin may reduce burn-related pruritus compared with cetirizine (MD -2.40 VAS, 95% CI -4.14 to -0.66; 1 study, 40 participants). A change of 2 points represents a MCID. There is low-certainty evidence that gabapentin reduces the incidence of somnolence compared to cetirizine (RR 0.02, 95% CI 0.00 to 0.38; 1 study, 40 participants). No data were reported on pain in the included study. There is low-certainty evidence that pregabalin may result in a reduction in burn-related pruritus intensity compared with cetirizine with pheniramine maleate (MD -0.80 VAS, 95% CI -1.24 to -0.36; 1 study, 40 participants). A change of 2 points represents a MCID. There is low-certainty evidence that pregabalin reduces the incidence of somnolence compared to cetirizine (RR 0.04, 95% CI 0.00 to 0.69; 1 study, 40 participants). No data were reported on pain in the included study. There is moderate-certainty evidence that ondansetron probably results in a reduction in burn-related pruritus intensity compared with diphenhydramine (MD -0.76 on a 0 to 10 numeric analogue scale (NAS), 95% CI -1.50 to -0.02; 1 study, 38 participants). A change of 2 points represents a MCID. No data were reported on pain and adverse events in the included study. Topical therapies versus relevant comparators There is moderate-certainty evidence that enalapril ointment probably decreases mean burn-related pruritus compared with placebo control (MD -0.70 on a 0 to 4 scoring table for itching, 95% CI -1.04 to -0.36; 1 study, 60 participants). No data were reported on pain and adverse events in the included study. Physical modalities versus relevant comparators Compared with standard care, there is low-certainty evidence that massage may reduce burn-related pruritus (standardised mean difference (SMD) -0.86, 95% CI -1.45 to -0.27; 2 studies, 166 participants) and pain (SMD -1.32, 95% CI -1.66 to -0.98). These SMDs equate to a 4.60-point reduction in pruritus and a 3.74-point reduction in pain on a 10-point VAS. A change of 2 VAS points in itch represents a MCID. No data were reported on adverse events in the included studies. There is low-certainty evidence that extracorporeal shock wave therapy (ESWT) may reduce burn-related pruritus compared with sham stimulation (SMD -1.20, 95% CI -1.65 to -0.75; 2 studies, 91 participants). This equates to a 5.93-point reduction in pruritus on a 22-point 12-item Pruritus Severity Scale. There is low-certainty evidence that ESWT may reduce pain compared with sham stimulation (MD 2.96 on a 0 to 25 pressure pain threshold (PPT), 95% CI 1.76 to 4.16; 1 study, 45 participants). No data were reported on adverse events in the included studies. Laser scar revision versus untreated or placebo controls There is moderate-certainty evidence that pulsed high-intensity laser probably results in a reduction in burn-related pruritus intensity compared with placebo laser (MD -0.51 on a 0 to 1 Itch Severity Scale (ISS), 95% CI -0.64 to -0.38; 1 study, 49 participants). There is moderate-certainty evidence that pulsed high-intensity laser probably reduces pain compared with placebo laser (MD -3.23 VAS, 95% CI -5.41 to -1.05; 1 study, 49 participants). No data were reported on adverse events in the included studies.

AUTHORS' CONCLUSIONS

There is moderate to low-certainty evidence on the effects of 21 interventions. Most studies were small and at a high risk of bias related to blinding and incomplete outcome data. Where there is moderate-certainty evidence, practitioners should consider the applicability of the evidence for their patients.

Neuropathic pain in burn patients - A common problem with little literature: A systematic review

BACKGROUND

The prevalence of neuropathic pain (NP) in burn patients is reported in the literature to be as high as 80%1. Given the complexity of NP in burn patients and the wide range of treatments available, a systematic review of the literature is warranted to summarize our current understanding of management and treatment of NP in this population.

METHODS

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The following databases were queried to identify relevant articles: PubMed, Cochrane, Embase, Scopus, Ovid, and Web of Science. The main outcome measures were incidence and management of NP. Secondary outcomes included risk factors for NP.

RESULTS

Included articles presented findings from 11 different countries, capturing outcomes for 4366 patients. Risk factors for neuropathic pain in burn patients were identified, including older age, alcohol and substance abuse, current daily smoking, greater % total body surface area burns (TBSA), and longer hospitalizations. Pharmacologic treatments included gabapentin/pregabalin (n = 7), ascorbic acid (n = 1), and lidocaine (n = 1). Overall, the studies showed varied results regarding the efficacy of pharmacological treatments. While certain studies demonstrated gabapentanoids to be effective in reducing neuropathic symptoms, others found conflicting results. With regards to non-pharmacologic treatments, electroconvulsive therapy (n = 1), electropuncture (n = 1), nerve release/reconstruction (n = 2), and somatosensory feedback rehabilitation (n = 1) were used and demonstrated promise in reducing pain intensity and improving functionality.

CONCLUSIONS

Despite NP afflicting the majority of burn patients long after their injury, this systematic review demonstrates insufficient evidence on the pathophysiology, outcomes, and risk factors in NP, as well as the efficacy of various therapies. Future prospective and randomized studies evaluating the etiology of these factors can substantially improve our treatment strategies. This can allow for the development of well-delineated and evidence-based protocols in NP management in hopes of improving quality of life and both psychological and physical function in burn patients.

Burn Injury Complications Impacting Rehabilitation

Successful post-burn rehabilitation requires an understanding of a wide range of complications to maximize functional recovery. This article reviews a range of potential challenges including burn scar contracture, amputation, peripheral nerve injury, heterotopic ossification, dysphagia, altered skin physiology, pain, and pruritis. The overall focus is to serve as a guide for post-injury therapy and rehabilitation spanning the phases of care and considering evidence-based approaches, prevention, and treatment with an ultimate goal of aiding in the functional recovery and long-term quality of life for burn survivors.

Effectiveness and Adverse Events of Gabapentinoids as Analgesics for Patients with Burn Injuries: A Systematic Review with Meta-Analysis and Trial Sequential Analysis

(1) Background: Pain after a burn injury is difficult to endure, and emerging studies aim to ascertain the effects of gabapentin and pregabalin as non-opioid treatment options. (2) Methods: We searched for randomised controlled trials (RCTs) in six databases. The risk of bias was assessed using the RoB 2.0 tool. We performed meta-analysis and trial sequential analysis and used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology for judging the certainty of evidence (CoE). (3) Results: Five RCTs were included. Compared with placebo, gabapentinoids significantly decreased the pain intensity within 24 h (mean difference (MD) = -1.06, 95% confidence interval (CI): -1.47--0.65) and from 72 h to 9 days (MD = -0.82, 95% CI: -1.16--0.48), but not after 3 weeks (MD = -0.44, 95% CI: -1.31-0.42). Opioid consumption (mg/day) was reduced within 24 h (MD = -13.34, 95% CI: -22.16--4.52) and from 72 h to 9 days (MD = -7.87, 95% CI: -14.82--0.91). Increased risks of drowsiness (risk ratio (RR) = 3.255, 95% CI: 1.135-9.335) and dizziness (RR = 3.034, 95% CI: 1.006-9.147) were observed, but sensitivity analysis using the Bayesian method showed no increased risk. All endpoints were judged as low to very low CoE. (4) Conclusions: Gabapentinoids offer modest analgesic benefits as a component of multimodal pain management for burn injuries of less than 3 weeks. The adverse effects should be carefully monitored. Large-scale RCTs are warranted for the reinforcement of CoE in clinical use.

Pharmacologic Management of Pain, Agitation, and Delirium in Burn Patients

The majority of hospitalized burn patients experience pain, agitation, and delirium. The development of each one of these conditions can also lead to, or worsen, the others. Providers, therefore, need to thoroughly assess the underlying issue to determine the most effective treatment. Multimodal pharmacologic regimens are often used in conjunction with non-pharmacologic strategies to manage pain, agitation, and delirium. This review focuses on the pharmacologic management of these complicated patients in a critical-care setting.

[Neuropathic pruritus-Evidence-based treatment recommendations]

Neuropathic pruritus is a previously neglected symptom of a wide range of neurological diseases. Peripheral nerve or root compression syndromes, space-occupying lesions of the central nervous system, chronic inflammatory neurological diseases and polyneuropathy can cause neuropathic pruritus. Even when the identification of the underlying neurological disease is successful, a direct causal treatment is not always possible, hence an effective symptomatic treatment remains the only therapeutic option. The purpose of this review article is to present the current literature on various therapeutic agents and options in the treatment of neuropathic pruritus.

Co-Combination of Pregabalin and Withaniacoagulans-Extract-Loaded Topical Gel Alleviates Allodynia and Hyperalgesia in the Chronic Sciatic Nerve Constriction Injury for Neuropathic Pain in Animal Model

The current study reports the fabrication of co-combination gel using Pregabalin and Withania coagulans fruit extract to validate its effectiveness for neuropathic pain in chronic constriction injury (CCI) rat models. Three topical gels were prepared using Carbopol 934 through a pseudo-ternary phase diagram incorporating the Pregabalin (2.5%), Withania coagulans extract (2%), and co-combination of both Pregabalin (2.5%) and Withania coagulans extract (2%). Gels were characterized. FTIR showed a successful polymeric network of the gel without any interaction. The drug distribution at the molecular level was confirmed by XRD. The AFM images topographically indicated the rough surface of gels with a size range from 0.25 to 330 nm. DSC showed the disappearance of sharp peaks of the drug and extract, showing successful incorporation into the polymeric network of gels. The in vitro drug release of co-combination gel was 73% over 48 h. The mechanism of drug release by combination gel was Higuchi+ fickian with values of n (0.282) and R2 (0.947). An in vivo study for pain assessment via four methods: (i) heat hyperalgesia, (ii) cold allodynia, (iii) mechano-hyperalgesia, and (iv) dynamic mechano-allodynia, confirmed that topical treatment with co-combination gel reduced the pain significantly as indicated by the p value: R1 (p < 0.001), R2 (p < 0.001), R3 (p < 0.015), and R4 (p < 0.0344). The significance order was R2 (****) > R1 (***) > R3 (**) > R4 (*) > R5 (ns).

Preparation, Characterization of Pregabalin and Withania coagulans Extract-Loaded Topical Gel and Their Comparative Effect on Burn Injury

The current study depicts the comparative effects of nanogel using Withania coagulans extract, pregabalin alone, and a co-combination gel. The gels prepared were then analyzed for conductivity, viscosity, spread ability, globule size, zeta potential, polydispersity index, and TEM. The globule size of the co-combination gel, determined by zeta sizer, was found to be (329 ± 0.573 nm). FTIR analysis confirms the successful development of gel, without any interaction. Drug distribution at the molecular level was confirmed by XRD. DSC revealed no bigger thermal changes. TEM images revealed spherical molecules with sizes of 200 nm for the co-combination gel. In vivo studies were carried out by infliction of third degree burn wounds on rat skin, and they confirmed that pregabalin and Withania coagulans heals the wound more effectively, with a wound contraction rate of 89.95%, compared to remaining groups. Anti-inflammatory activity (IL-6 and TNF-α), determined by the ELISA technique, shows that the co-combination gel group reduces the maximum inflammation with TNF-α value (132.2 pg/mL), compared to the control (140.22 pg/mL). Similarly, the IL-6 value was found to be (78 pg/mL) for the co-combination gel and (81 pg/mL) in the case of the control. Histopathologically, the co-combination gel heals wounds more quickly, compared to individual gel. These outcomes depict that a co-combination gel using plant extracts and drugs can be successfully used to treat burn injury.

Strategies aimed at preventing long-term opioid use in trauma and orthopaedic surgery: a scoping review

Background

Long-term opioid use, which may have significant individual and societal impacts, has been documented in up to 20% of patients after trauma or orthopaedic surgery. The objectives of this scoping review were to systematically map the research on strategies aiming to prevent chronic opioid use in these populations and to identify knowledge gaps in this area.

Methods

This scoping review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist. We searched seven databases and websites of relevant organizations. Selected studies and guidelines were published between January 2008 and September 2021. Preventive strategies were categorized as: system-based, pharmacological, educational, multimodal, and others. We summarized findings using measures of central tendency and frequency along with p-values. We also reported the level of evidence and the strength of recommendations presented in clinical guidelines.

Results

A total of 391 studies met the inclusion criteria after initial screening from which 66 studies and 20 guidelines were selected. Studies mainly focused on orthopaedic surgery (62,1%), trauma (30.3%) and spine surgery (7.6%). Among system-based strategies, hospital-based individualized opioid tapering protocols, and regulation initiatives limiting the prescription of opioids were associated with statistically significant decreases in morphine equivalent doses (MEDs) at 1 to 3 months following trauma and orthopaedic surgery. Among pharmacological strategies, only the use of non-steroidal anti-inflammatory drugs and beta blockers led to a significant reduction in MEDs up to 12 months after orthopaedic surgery. Most studies on educational strategies, multimodal strategies and psychological strategies were associated with significant reductions in MEDs beyond 1 month. The majority of recommendations from clinical practice guidelines were of low level of evidence.

Conclusions

This scoping review advances knowledge on existing strategies to prevent long-term opioid use in trauma and orthopaedic surgery patients. We observed that system-based, educational, multimodal and psychological strategies are the most promising. Future research should focus on determining which strategies should be implemented particularly in trauma patients at high risk for long-term use, testing those that can promote a judicious prescription of opioids while preventing an illicit use, and evaluating their effects on relevant patient-reported and social outcomes.

Patient-centred outcomes are under-reported in the critical care burns literature: a systematic review

BACKGROUND

Developments in the care of critically ill patients with severe burns have led to improved hospital survival, but long-term recovery may be impaired. The extent to which patient-centred outcomes are assessed and reported in studies in this population is unclear.

METHODS

We conducted a systematic review to assess the outcomes reported in studies involving critically ill burns patients. Randomised controlled trials (RCTs) and cohort studies on the topics of fluid resuscitation, analgesia, haemodynamic monitoring, ventilation strategies, transfusion targets, enteral nutrition and timing of surgery were included. We assessed the outcomes reported and then classified these according to two suggested core outcome sets.

RESULTS

A comprehensive search returned 6154 studies; 98 papers met inclusion criteria. There were 66 RCTs, 19 clinical studies with concurrent controls and 13 interventional studies without concurrent controls. Outcome reporting was inconsistent across studies. Pain, reported using the visual analogue scale, fluid volume administered and mortality were the only outcomes measured in more than three studies. Sixty-six studies (67%) had surrogate primary outcomes. Follow-up was poor, with median longest follow-up across all studies 5 days (IQR 3-28). When compared to the suggested OMERACT core outcome set, 53% of papers reported on mortality, 28% reported on life impact, 30% reported resource/economic outcomes and 95% reported on pathophysiological manifestations. Burns-specific Falder outcome reporting was globally poor, with only 4.3% of outcomes being reported across the 98 papers.

CONCLUSION

There are deficiencies in the reporting of outcomes in the literature pertaining to the intensive care management of patients with severe burns, both with regard to the consistency of outcomes as well as a lack of focus on patient-centred outcomes. Long-term outcomes are infrequently reported. The development and validation of a core outcome dataset for severe burns would improve the quality of reporting.

Prescribing of Gabapentinoids with or without opioids after burn injury in the US, 2012-2018

Burn injury pain manifests as a combination of inflammatory, nociceptive, and neuropathic features. While opioids are the mainstay of burn pain management, non-opioid medications, such as gabapentinoids, have also been considered as they target the central nervous system. Increased opioid adverse events and overdose deaths in the United States led to the 2014 and 2016 guidelines to reduce opioid prescribing and consider alternatives, such as gabapentinoids. In the context of burn, the rate of gabapentinoid prescribing at the national level is unknown and it is unclear whether any shift has occurred in prescribing practices over time. We conducted a population level cohort study of adult burn patients from 2012 to 2018 to evaluate the rates and determinants of gabapentinoid prescribing, with and without opioids. Of 98,001 patients with burn, 22,521 (22.98%) received opioids and/or gabapentinoids (GABA). GABA represented 2.4% of prescriptions in 2012, but increased to 7.2% by 2018, while GABA-opioid co-prescriptions increased from 2.3% to 5.1%. The rate of increase in GABA prescriptions was higher for those aged 50-65 years or residing in the South. After adjustment, GABA was 44% more likely to be prescribed in 2017 and 2018 compared to 2012 and 2013, opioids were 38% less likely, while co-prescribing did not show a statistically significant change. Our study showed a modest increase in gabapentinoids' outpatient prescribing for burn patients after the 2014 and 2016 guidelines, indicating more opportunities for prescribers to expand non-opioid pain management in this population.

Neuropathic agents in the management of pruritus in burn injuries: a systematic review and meta-analysis

Objectives

Pruritus is a common and often distressing complication after a burn injury. The purpose of this review is to explore the efficacy of drugs classically used to treat neuropathic pain in the management of pruritus after burn injury.

Methods

A systematic literature search of medical databases was conducted to find studies investigating drugs listed in the National Institute for Health and Care Excellence (NICE) guideline (CG173, "neuropathic pain in adults") for the management of pruritus after burn injury in patients of any age. Controlled studies were stratified by the drug class studied and their risk of bias before conducting meta-analysis. A narrative review of case series or observational studies was presented. Severity of pruritus at any time point, with all quantitative and qualitative measures, was included.

Results

Fifteen studies were included in the final analysis, 10 investigated the use of gabapentinoids, 4 studied doxepin, and 1 local anesthetic agents. Meta-analysis of three randomized controlled trials (RCTs) demonstrated that the use of gabapentinoids was associated with an improvement in mean VAS (Visual Analog Scale) 0-10 scores of 2.96 (95% confidence interval (95% CI) 1.20 to 4.73, p<0.001) when compared with placebo or antihistamine. A meta-analysis of four RCTs investigating topical doxepin showed an improvement in mean VAS scores of 1.82 (95% CI 0.55 to 3.09, p<0.001). However, when excluding two studies found to be at high risk of bias, no such improvement was found (-0.32, 95% CI -1.64 to -0.99, p=0.83).

Conclusion

This study suggests that gabapentinoids are beneficial in the management of burn-related pruritus. There is a lack of evidence to suggest that doxepin is an effective treatment. Topical local anesthetic agents may be safe and beneficial, but studies are scarce.

Level of evidence

Systematic review, level II.

Risk Factors Associated With the Progression From Acute to Chronic Neuropathic Pain After Burn-Related Injuries

BACKGROUND

Pain, unrelated to the initial thermal trauma itself, can result after burn injury and prolong the recovery/rehabilitation phase of the patient's care. This pain, after discharge from the burn unit, may be acute and self-limiting or chronic and contribute to long-term patient morbidity. The purposes of this study were to compare burn patients who had, after discharge from the burn unit, only acute pain with burn patients who developed chronic, neuropathic pain (CNP) and to determine risks factors for progression from acute to chronic pain in the setting of a burn center.

METHODS

A single-center, retrospective chart review of patients admitted to the adult burn center was performed from January 1, 2014, to January 1, 2019. Patients included were older than 15 years, sustained a burn injury, and admitted to the burn unit. Chronic pain was defined as pain lasting greater than 6 months after discharge from the burn unit. Pain descriptors included shooting, stabbing, sharp, burning, tingling, numbness, throbbing, pruritus, intermittent, and/or continuous dysesthetic sensations after the burn. Patients were excluded if they had preexisting neuropathic pain due to an underlying medical illness or previous surgery.

RESULTS

During a 5-year period, of the 1880 admissions to the burn unit, 143 burn patients developed post-initial-onset pain as a direct result of their burn. Of the 143 patients with acute pain, pain resolved in 30 patients, whereas pain progressed to CNP in 113 patients (79%). Patient follow-up was a median (interquartile range [IQR]) of 26.5 (10-45) months. Patients whose pain progressed to CNP had significantly greater percent total body surface area burns (median [IQR], 6 [3-25] vs 3 [1-10]; P = 0.032), had more full-thickness burns (66/113 [58%] vs 8/30 [27%] patients, P = 0.004), had surgery (85/113 [75%] vs 16/30 [53%] patients, P = 0.042), had more surgical procedures (median [IQR], 2 [1-6] vs 1 [0-3], P = 0.002), and developed more complications (32/113 [28%] vs 2/30 [7%] patients, P = 0.014) compared with those with acute neuropathic pain, respectively.

CONCLUSIONS

Burn patients who progressed from having acute to CNP had significantly greater percent total body surface area burns, had more full-thickness burns, had surgery, had more surgical procedures, and developed more complications compared with burn patients with only acute pain.

American Burn Association Guidelines on the Management of Acute Pain in the Adult Burn Patient: A Review of the Literature, a Compilation of Expert Opinion, and Next Steps

The ABA pain guidelines were developed 14 years ago and have not been revised despite evolution in the practice of burn care. A sub-committee of the American Burn Association's Committee on the Organization and Delivery of Burn Care was created to revise the adult pain guidelines. A MEDLINE search of English-language publications from 1968 to 2018 was conducted using the keywords "burn pain," "treatment," and "assessment." Selected references were also used from the greater pain literature. Studies were graded by two members of the committee using Oxford Centre for Evidence-based Medicine-Levels of Evidence. We then met as a group to determine expert consensus on a variety of topics related to treating pain in burn patients. Finally, we assessed gaps in the current knowledge and determined research questions that would aid in providing better recommendations for optimal pain management of the burn patient. The literature search produced 189 papers, 95 were found to be relevant to the assessment and treatment of burn pain. From the greater pain literature 151 references were included, totaling 246 papers being analyzed. Following this literature review, a meeting to establish expert consensus was held and 20 guidelines established in the areas of pain assessment, opioid medications, nonopioid medications, regional anesthesia, and nonpharmacologic treatments. There is increasing research on pain management modalities, but available studies are inadequate to create a true standard of care. We call for more burn specific research into modalities for burn pain control as well as research on multimodal pain control.

Multimodal Analgesia and Discharge Opioid Requirements in Burn Patients

Analgesia in burn patients is challenging given the complexity of burn pain and prolonged need beyond hospital admission. Given the risks of opioids, the impact of multimodal analgesia postdischarge needs to be further elucidated in this population. This retrospective, single-center cohort study evaluated adult burn patients who were consecutively admitted to the burn service with at least 10% total body surface area burned and subsequently followed in the burn clinic between February 2015 and September 2018. Subjects were separated into two cohorts based on discharge pain regimens: multimodal and nonmultimodal. The primary outcome was the change in opioid requirements (measured in oral morphine equivalents) between discharge and first follow-up interval. Secondary outcomes included the classes of multimodal agents utilized and a comparison of opioid requirements between the last 24 hours of admission and discharge. A total of 152 patients were included for analysis, 76 in the multimodal cohort and 76 in the nonmultimodal cohort. The multimodal cohort was noted to have increased total body surface area burned and prolonged number of days spent in the intensive care unit at baseline; however, the multimodal cohort exhibited a more significant decrease in opioid requirements from discharge to first follow-up interval when compared with the nonmultimodal cohort (106.6 vs 75.4 mg, P = .039).

Post-Burn Pruritus

Post-burn pruritus is the pruritus that occurs after burn during the rehabilitation and healing process of burn wounds. The post-burn pruritus is a common and serious complication of burn injury, which severely lowers the quality of life of the patient. Many potential treatments are available for pruritus but there is no consensus of the best single treatment yet. The precise mechanism of post-burn pruritus has not been elucidated, but it appears to have pruritogenic and neuropathic aspects. Clinically, post-burn pruritus tends to be intractable to conventional treatment but rather responds to neuroleptic agents, such as gabapentin and pregabalin. During wound healing, various neuropeptides secreted from the nerves of the skin control epidermal and vascular proliferation and connective tissue cells. When keratinocytes are activated by an itch-inducing substance, they secrete a variety of inflammatory substances that increase the susceptibility of the itch receptor. There are two mechanisms underlying post-burn neuropathic pruritus. The first one is peripheral sensitization. The second one is the intact nociceptor hypothesis. An effective treatment for post-burn pruritus will also be effective in other neuropathic and intractable itching. In this review, we summarized the interaction and mechanism of keratinocytes, immune cells, and nerve fibers related to post-burn pruritus.

Perioperative Multimodal Analgesia Reduces Opioid Use Following Skin Grafting in Nonintubated Burn Patients

Hundreds of patients are treated for burn injuries each year at University of Wisconsin School of Medicine and Public Health. Pain management is particularly challenging during dressing changes and following skin grafting procedures. We performed a retrospective chart review from January 2011 through June 2018 to evaluate the effect of nonopioid analgesic medications on opioid use in nonintubated patients. Our primary outcome was the change in opioid use following the procedure. We found that most patients (69%) report severe pain (Numeric Rating Scale ≥7) immediately after autologous skin grafting. On average, patients required an additional 52 mg of oral morphine equivalents (ME) in the 24 h after the procedure compared with the 24 h before. The use of perioperative nonopioid analgesia varied between patients (acetaminophen 29%, gabapentin 29%, ketamine 35%, and all three 8%). Patients who received either gabapentin or a combination of acetaminophen, gabapentin, and ketamine had a smaller increase in their opioid use than patients who did not receive the medications (-25 ME, 95% confidence interval [-46, -4]; P = .018 and -47 ME, [-81, -11]; P = .010, respectively). These results support using a combination of acetaminophen, gabapentin, and ketamine for perioperative analgesia in burn patients undergoing autologous skin grafting.

Society of Dermatology Hospitalists supportive care guidelines for the management of Stevens-Johnson syndrome/toxic epidermal necrolysis in adults

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening conditions with high morbidity and mortality. Supportive care management of SJS/TEN is highly variable. A systematic review of the literature was performed by dermatologists, ophthalmologists, intensivists, and gynecologists with expertise in SJS/TEN to generate statements for supportive care guideline development. Members of the Society of Dermatology Hospitalists with expertise in SJS/TEN were invited to participate in a modified, online Delphi-consensus. Participants were administered 9-point Likert scale questionnaires regarding 135 statements. The RAND/UCLA Appropriateness Method was used to evaluate and select proposed statements for guideline inclusion; statements with median ratings of 6.5 to 9 and a disagreement index of ≤1 were included in the guideline. For the final round, the guidelines were appraised by all of the participants. Included are an evidence-based discussion and recommendations for hospital setting and care team, wound care, ocular care, oral care, urogenital care, pain management, infection surveillance, fluid and electrolyte management, nutrition and stress ulcer prophylaxis, airway management, and anticoagulation in adult patients with SJS/TEN.

Prevalence and associated predictors for patients developing chronic neuropathic pain following burns

BACKGROUND

Chronic pain, unrelated to the burn itself, can manifest as a long-term complication in patients sustaining burn injuries. The purpose of this study was to determine the prevalence of chronic neuropathic pain (CNP) and compare burn characteristics between patients who developed CNP and patients without CNP who were treated at a burn center.

METHODS

A single-center, retrospective analysis of 1880 patients admitted to the adult burn center was performed from 1 January 2014 to 1 January 2019. Patients included were over the age of 15 years, sustained a burn injury and were admitted to the burn center. CNP was diagnosed clinically following burn injury. Patients were excluded from the definition of CNP if their pain was due to an underlying illness or medication. Comparisons between patients admitted to the burn center with no pain and patients admitted to the burn center who developed CNP were performed.

RESULTS

One hundred and thirteen of the 1880 burn patients developed CNP as a direct result of burn injury over 5 years with a prevalence of 6.01%. Patients who developed CNP were a significantly older median age (54 years vs. 46 years, p = 0.002), abused alcohol (29% vs. 8%, p < 0.001),abused substances (31% vs. 9%, p < 0.001), were current daily smokers (73% vs. 33%, p < 0.001), suffered more full-thickness burns (58% vs. 43%, p < 0.001), greater median percent of total body surface area (%TBSA) burns (6 vs. 3.5, p < 0.001), were more often intubated on mechanical ventilation (33% vs. 14%, p < 0.001), greater median number of surgeries (2 vs. 0, p < 0.001) and longer median hospital length of stay (LOS) (10 days vs. 3 days, p < 0.001), compared to those who did not develop CNP, respectively. Median patient follow-up was 27 months.

CONCLUSIONS

The prevalence of CNP over 5 years was 6.01% in the burn center. Older ages, alcohol abuse, substance abuse, current daily smoking, greater percent of total body surface area (%TBSA) burns, third degree burns, being intubated on mechanical ventilation, having more surgeries and longer hospital LOS were associated with developing CNP following burn injury, compared to patients who did not develop CNP following burn injury.

Analgesic use in contemporary burn practice: Applications to burn mass casualty incident planning

BACKGROUND

Determining the amount of analgesics required will help burn centers improve their ability to plan for a burn mass casualty incident (BMCI). We sought to quantify the amount of analgesics needed in an inpatient burn population. We hoped that assessing the analgesic use in daily burn care practice will potentially help estimate opioid needs in a burn mass casualty incident (BMCI).

METHODS

We included patients with burns covering equal to or less than 30% total body surface area (TBSA), admitted from spring 2013 to spring 2015. Patient records were reviewed for analgesics and adjuncts, pain scores, age and TBSA. The doses of the different opioids administered were converted into morphine equivalent doses (MED).

RESULTS

We enrolled 141 acute burn survivors with a mean TBSA of 8.2±0.6%. The lowest daily average MED per person was 24.6±2.0mg MED, recorded on the day of injury. The daily average MED per person increased until it peaked at 52.5±5.6mg MED at day 8 post-burn. Then, it declined to 24.6±3.4mg MED by day 14. Bivariate regression analysis of average MED by TBSA showed a significant positive correlation (p<0.001). The analysis of average MED by age showed a significant negative correlation (p<0001).

CONCLUSION

Our study quantified opioid requirements in an inpatient burn population and identified TBSA (positively) and age (negatively) as significant predictors.

A Review of Adjunctive Therapies for Burn Injury Pain During the Opioid Crisis

Opioids are the mainstay of pain management after burn injury. The United States currently faces an epidemic of opioid overuse and abuse, while simultaneously experiencing a nationwide shortage of intravenous narcotics. Adjunctive pain management therapies must be sought and utilized to reduce the use of opioids in burn care to prevent the long-term negative effects of these medications and to minimize the dependence on opioids for analgesia. The purpose of this review was to identify literature on adjunctive pain management therapies that have been demonstrated to reduce pain severity or opioid consumption in adult burn patients. Three databases were searched for prospective studies, randomized controlled trials, and systematic reviews that evaluated adjunctive pain management strategies published between 2008 and 2019 in adult burn patients. Forty-six studies were analyzed, including 24 randomized controlled trials, six crossover trials, and 10 systematic reviews. Various adjunctive pain management therapies showed statistically significant reduction in pain severity. Only one randomized controlled trial on music therapy for acute background pain showed a reduction in opioid use. One cohort study on hypnosis demonstrated reduced opioid use compared with historical controls. We recommend the development of individualized analgesic regimens with the incorporation of adjunctive therapies in order to improve burn pain management in the midst of an abuse crisis and concomitant national opioid shortage.

Pregabalin in the reduction of pain and opioid consumption after burn injuries: A preliminary, randomized, double-blind, placebo-controlled study

BACKGROUND

The primary objective of the study was to evaluate the efficacy of 300 milligrams (mg) and 600 mg of pregabalin compared to placebo in the reduction of pain in patients with noncritical partial and full thickness burn injuries.

METHODS

A prospective, randomized, double-blinded, single center, placebo-controlled trial was conducted. Simple randomization method was used in this trial. After subjects met all the inclusion and none of the exclusion criteria, they were randomized and assigned to 1 of the 3 18-day treatments groups: Pregabalin 300 group, Pregabalin 600 group, or Placebo group. Demographics and clinical characteristics were recorded. The severity of pain was assessed by using the visual analog scale for pain intensity at baseline on day 3, day 9 ± 3, day 25 ± 7, day 90 ± 6, and day 180 ± 12.

RESULTS

A total of 54 subjects were randomly assigned, and 51 were included in the data analysis. Demographics and clinical characteristics did not differ significantly between the 3 groups. There was a statistically significant difference in pain between the Pregabalin 300 and Pregabalin 600 groups (P-value = .0260). The Pregabalin 300 group had 17.93 units (95% confidence interval: 1.83-34.04) higher pain scores on average than the Pregabalin 600 group, regardless of time. The adjusted P-value comparing 0 to 300 was .1618, while the adjusted P-value for 0 versus 600 was .5304. There was an overall difference in pain across time regardless of study group (P-value = <.0001). An overall difference in opioid consumption (P-value = .0003) and BSHS (P-value = .0013) across time regardless of study group was noted.

CONCLUSIONS

Pregabalin could be part of a promising multimodal analgesic regimen in noncritical burn population. Future placebo-controlled studies assessing the use of pregabalin in burn victim patients may further endorse our findings.

A Clinical Overview of Off-label Use of Gabapentinoid Drugs

BACKGROUND

The gabapentinoid drugs gabapentin and pregabalin were originally developed as antiseizure drugs but now are prescribed mainly for treatment of pain. For gabapentin, the only pain-related indication approved by the US Food and Drug Administration (FDA) is postherpetic neuralgia. For pregabalin, FDA-approved indications related to pain are limited to postherpetic neuralgia, neuropathic pain associated with diabetic neuropathy or spinal cord injury, and fibromyalgia. Despite these limited indications, gabapentin and pregabalin are widely prescribed off-label for various other pain syndromes. Such use is growing, possibly because clinicians are searching increasingly for alternatives to opioids.

OBSERVATIONS

This report summarizes the limited published evidence to support off-label gabapentinoid uses, describes clinical cases in which off-label use is problematic, and notes how review articles and guidelines tend to overstate gabapentinoid effectiveness.

CONCLUSIONS

Clinicians who prescribe gabapentinoids off-label for pain should be aware of the limited evidence and should acknowledge to patients that potential benefits are uncertain for most off-label uses.

Burn Pain: A Systematic and Critical Review of Epidemiology, Pathophysiology, and Treatment

Objective

This review aims to examine the available literature on the epidemiology, pathophysiology, and treatment of burn-induced pain.

Methods

A search was conducted on the epidemiology of burn injury and treatment of burn pain utilizing the database Medline, and all relevant articles were systemically reviewed. In addition, a critical review was performed on the pathophysiology of burn pain and animal models of burn pain.

Results

The search on the epidemiology of burn injury yielded a total of 163 publications of interest, 72 of which fit the inclusion/exclusion criteria, with no publications providing epidemiological data on burn injury pain management outcomes. The search on the treatment of burn pain yielded a total of 213 publications, 14 of which fit the inclusion/exclusion criteria, highlighting the limited amount of evidence available on the treatment of burn-induced pain.

Conclusions

The pathophysiology of burn pain is poorly understood, with limited clinical trials available to assess the effectiveness of analgesics in burn patients. Further studies are needed to identify new pharmacological targets and treatments for the effective management of burn injury pain.

The vicious cycle of itch and anxiety

Chronic itch is associated with increased stress, anxiety, and other mood disorders. In turn, stress and anxiety exacerbate itch, leading to a vicious cycle that affects patient behavior (scratching) and worsens disease prognosis and quality of life. This cycle persists across chronic itch conditions of different etiologies and even to some extent in healthy individuals, suggesting that the final common pathway for itch processing (the central nervous system) plays a major role in the relationship between itch and anxiety. Pharmacological and nonpharmacological treatments that reduce anxiety have shown promising anti-itch effects. Further research is needed to establish specific central mechanisms of the itch-anxiety cycle and provide new targets for treatment.

Pregabalin versus placebo in targeting pro-nociceptive mechanisms to prevent chronic pain after whiplash injury in at-risk individuals - a feasibility study for a randomised controlled trial

BACKGROUND

Whiplash-associated disorders (WAD) are an enormous and costly burden to Australian society. Up to 50% of people who experience a whiplash injury will never fully recover. Whiplash is resistant to treatment and no early management approach has yet been shown to prevent chronic pain. The early presence of central sensitization is associated with poor recovery. Pregabalin's effects on central sensitization indicate the potential to prevent or modulate these processes after whiplash injury and to improve health outcomes, but this has not been investigated. This paper describes the protocol for a feasibility study for a randomised controlled trial of pregabalin plus evidence-based advice compared to placebo plus evidence-based advice for individuals with acute whiplash injury who are at risk of poor recovery.

METHODS

This double blind, placebo-controlled randomised feasibility study will examine the feasibility and potential effectiveness of pregabalin and evidence-based advice (intervention) compared to placebo and evidence-based advice (control) for individuals with acute whiplash injury at risk of poor recovery. Thirty participants (15 per group) aged 18-65 years with Grade II WAD, within 48 hours of injury and currently experiencing at least moderate pain (NRS: ≥ 5/10) will be recruited from Emergency Departments of public hospitals in Queensland, Australia. Pregabalin will be commenced at 75 mg bd and titrated up to 300 mg bd as tolerated for 4 weeks followed by 1 week of weaning.

RESULTS

The feasibility of trial procedures will be tested, as well as the potential effect of the intervention on the outcomes. The primary outcome of neck pain intensity at 3 months from randomisation will be compared between the treatment groups using standard analysis of variance techniques.

DISCUSSION

Feasibility and potential effectiveness data will inform an appropriately powered full trial, which if successful, will provide an effective and cost-effective intervention for a costly and treatment resistant condition. It will also have implications for the early management of other traumatic conditions beyond whiplash.

TRIAL REGISTRATION

Clinical Trials Primary Registry: Australian and New Zealand Clinical Trials Registry.

CLINICAL TRIAL REGISTRATION NUMBER

ACTRN12617000059369 . Date of Registration: 11/01/2017. Primary Trial Sponsor: The University of Queensland, Brisbane QLD 4072 Australia.

Burn injury: Challenges and advances in burn wound healing, infection, pain and scarring

Severe burn injuries are the most traumatic and physically debilitating injuries affecting nearly every organ system and leading to significant morbidity and mortality. Early burn wound excision and skin grafting are common clinical practices that have significantly improved the outcomes for severe burn injured patients by reducing mortality rate and days of hospital stay. However, slow wound healing, infection, pain, and hypertrophic scarring continue to remain a major challenge in burn research and management. In the present article, we review and discuss issues in the current treatment of burn injuries; the advances and novel strategies developed in the past decade that have improved burn management; and also, pioneer ideas and studies in burn research which aims to enhance burn wound care with a focus on burn wound infection, pain management, treatments for scarring and skin tissue engineering.

Early anticoagulation therapy for severe burns complicated by inhalation injury in a rabbit model

The aim of the present study was to determine the effects of early anticoagulation treatment on severe burns complicated by inhalation injury in a rabbit model. Under anesthetization, an electrical burns instrument (100°C) was used to scald the backs of rabbits for 15 sec, which established a 30% III severe burns model. Treatment of the rabbits with early anticoagulation effectively improved the severe burns complicated by inhalation injury-induced lung injury, reduced PaO₂, PaCO₂ and SPO₂ levels, suppressed the expression of tumor necrosis factor-α, interleukin (IL)-1β and IL-6, and increased the activity of IL-10. In addition, it was found that early anticoagulation treatment effectively suppressed the activities of caspase-3 and caspase-9, upregulated the protein expression of vascular endothelial growth factor (VEGF) and decreased the protein expression of protease-activated receptor 1 (PAR1) in the severe burns model. It was concluded that early anticoagulation treatment affected the severe burns complicated by inhalation injury in a rabbit model through the upregulation of VEGF and downregulation of PAR1 signaling pathways. Thus, early anticoagulation is a potential therapeutic option for severe burns complicated by inhalation injury.

Exploring Opioid-Sparing Multimodal Analgesia Options in Trauma: A Nursing Perspective

Challenges with opioids (e.g., adverse events, misuse and abuse with long-term administration) have led to a renewed emphasis on opioid-sparing multimodal management of trauma pain. To assess the extent to which currently available evidence supports the efficacy and safety of various nonopioid analgesics and techniques to manage trauma pain, a literature search of recently published references was performed. Additional citations were included on the basis of authors' knowledge of the literature. Effective options for opioid-sparing analgesics include oral and intravenous (IV) acetaminophen; nonsteroidal anti-inflammatory drugs available via multiple routes; and anticonvulsants, which are especially effective for neuropathic pain associated with trauma. Intravenous routes (e.g., IV acetaminophen, IV ketorolac) may be associated with a faster onset of action than oral routes. Additional adjuvants for the treatment of trauma pain are muscle relaxants and alpha-2 adrenergic agonists. Ketamine and regional techniques play an important role in multimodal therapy but require medical and nursing support. Nonpharmacologic treatments (e.g., cryotherapy, distraction techniques, breathing and relaxation, acupuncture) supplement pharmacologic analgesics and can be safe and easy to implement. In conclusion, opioid-sparing multimodal analgesia addresses concerns associated with high doses of opioids, and many pharmacologic and nonpharmacologic options are available to implement this strategy. Nurses play key roles in comprehensive patient assessment; administration of patient-focused, opioid-sparing, multimodal analgesia in trauma; and monitoring for safety concerns.

Peripheral Neuropathy and Nerve Compression Syndromes in Burns

Peripheral neuropathy and nerve compression syndromes lead to substantial morbidity following burn injury. Patients present with pain, paresthesias, or weakness along a specific nerve distribution or experience generalized peripheral neuropathy. The symptoms manifest at various times from within one week of hospitalization to many months after wound closure. Peripheral neuropathy may be caused by vascular occlusion of vasa nervorum, inflammation, neurotoxin production leading to apoptosis, and direct destruction of nerves from the burn injury. This article discusses the natural history, diagnosis, current treatments, and future directions for potential interventions for peripheral neuropathy and nerve compression syndromes related to burn injury.

Principles of Burn Pain Management

This article describes pathophysiology of burn injury-related pain and the basic principles of burn pain management. The focus is on concepts of perioperative and periprocedural pain management with extensive discussion of opioid-based analgesia, including patient-controlled analgesia, challenges of effective opioid therapy in opioid-tolerant patients, and opioid-induced hyperalgesia. The principles of multimodal pain management are discussed, including the importance of psychological counseling, perioperative interventional pain procedures, and alternative pain management options. A brief synopsis of the principles of outpatient pain management is provided.

Professor Tess Cramond (1926–2015): Contributions to Anaesthesia and Pain Medicine

Professor Tess Cramond joined the Queensland anaesthesia workforce in 1958, and contributed to high standards of clinical practice, pain management, training, scholarship and research. Evidence of her excellence, within the clinical, political and community spheres was recognised by multiple awards. Though deceased in 2015, she remains a role model for all physicians, using her expert knowledge, technical skills, clinical reasoning, emotions and values for the benefit of the individuals and community which she served.

Burns management in ICU: Quality of the evidence: A systematic review

BACKGROUND

The objective of this study was to assess the quality of readily available evidence regarding critical care aspects of the management of patients with severe burn injuries.

METHOD

PUBMED, EMBASE, Cochrane Databases and bibliographies of included studies and burns review articles were searched from inception of databases to end of February 2015. We included systematic reviews, randomised controlled trials (RCTs) and cohort studies with concurrent controls on the topics of (a) fluid resuscitation (b) analgesia (c) haemodynamic monitoring and targets (d) ventilation (e) blood transfusion. The quality of the studies was assessed using validated tools.

RESULTS

Fifty six studies fulfilled the inclusion criteria. Twenty three on fluid resuscitation, 22 on analgesia, nine on haemodynamic monitoring and two on ventilation. No studies were found on blood transfusion practice. There were ten systematic reviews, 38 RCTs and eight cohort studies with concurrent controls. The majority of studies were single centre trials with small numbers of patients, surrogate outcomes and high risk of bias.

CONCLUSIONS

There is very little high quality evidence to guide clinical practice in early management of the severely burnt patient. Eleven of 56 studies found in our search of critical care topics were of good methodological quality with low risk of bias.

Progress of clinical practice on the management of burn-associated pain: Lessons from animal models

Opioid-based analgesics provide the mainstay for attenuating burn pain, but they have a myriad of side effects including respiratory depression, nausea, impaired gastrointestinal motility, sedation, dependence, physiologic tolerance, and opioid-induced hyperalgesia. To test and develop novel analgesics, validated burn-relevant animal models of pain are indispensable. Herein we review such animal models, which are mostly limited to rodent models of burn-induced, inflammatory, and neuropathic pain. The latter two are pain syndromes that provide insight into the pain caused by systemic pro-inflammatory cytokines and direct injury to nerves (e.g., after severe burn), respectively. To date, no single animal model optimally mimics the complex pathophysiology and pain that a human burn patient experiences. No currently available burn-pain model examines effects of pharmacological intervention on wound healing. As cornerstones of pain and wound healing, pro-inflammatory mediators may be utilized for insight into both processes. Moreover, common clinical concerns such as systemic inflammatory response syndrome and multiple organ dysfunction remain unaddressed. For development of analgesics, these aberrations can significantly alter the potential efficacy and/or adverse effects of a prescribed analgesic following burn trauma. We therefore suggest that a multi-model strategy would be the most clinically relevant when evaluating novel analgesics for use in burn patients.

Pain and the thermally injured patient-a review of current therapies

Thermally injured patients experience tremendous pain from the moment of injury to months or years after their discharge from the hospital. Pain is therefore a critical component of proper management of burns. Although the importance of pain is well recognized, it is often undertreated. Acute uncontrolled pain has been shown to increase the incidence of mental health disorders and increase the incidence of suicide after discharge. Long-term poor pain control leads to an increase in the incidence of persistent pain. Most burn centers have used opioids as the mainstay analgesic, but recently, the significant side effects of opioids have led to the implementation of new and combined therapeutics. Pharmacological agents such as gabapentin, clonidine, dexmedetomidine, and ketamine have all been suggested as adjuncts to opioids in the treatment of burn pain. Nonpharmacological therapies such as hypnosis, virtual reality devices, and behavioral therapy are also essential adjuncts to current medications. This review aims at identifying the currently available pharmacological and nonpharmacological options for optimal pain management in the adult burn population.

Reporting of sample size calculations in analgesic clinical trials: ACTTION systematic review

Sample size calculations determine the number of participants required to have sufficiently high power to detect a given treatment effect. In this review, we examined the reporting quality of sample size calculations in 172 publications of double-blind randomized controlled trials of noninvasive pharmacologic or interventional (ie, invasive) pain treatments published in European Journal of Pain, Journal of Pain, and Pain from January 2006 through June 2013. Sixty-five percent of publications reported a sample size calculation but only 38% provided all elements required to replicate the calculated sample size. In publications reporting at least 1 element, 54% provided a justification for the treatment effect used to calculate sample size, and 24% of studies with continuous outcome variables justified the variability estimate. Publications of clinical pain condition trials reported a sample size calculation more frequently than experimental pain model trials (77% vs 33%, P < .001) but did not differ in the frequency of reporting all required elements. No significant differences in reporting of any or all elements were detected between publications of trials with industry and nonindustry sponsorship. Twenty-eight percent included a discrepancy between the reported number of planned and randomized participants. This study suggests that sample size calculation reporting in analgesic trial publications is usually incomplete. Investigators should provide detailed accounts of sample size calculations in publications of clinical trials of pain treatments, which is necessary for reporting transparency and communication of pre-trial design decisions.

PERSPECTIVE

In this systematic review of analgesic clinical trials, sample size calculations and the required elements (eg, treatment effect to be detected; power level) were incompletely reported. A lack of transparency regarding sample size calculations may raise questions about the appropriateness of the calculated sample size.

The pain quality response profile of a corticosteroid injections and heated lidocaine/tetracaine patch in the treatment of shoulder impingement syndrome

OBJECTIVES

To describe the effects of 2 pain treatments for shoulder impingement syndrome (SIS), and illustrate how investigators can use pain quality information to understand treatment response differences.

MATERIALS AND METHODS

This study presents pain quality data from a randomized open-label study comparing the effects of an injection of triamcinolone and up to twice daily application of a heated lidocaine/tetracaine (Trilexis) patch in individuals with SIS. Study participants completed a measure of pain quality at baseline and again on study days 14, 28, and 42 following initiation of 2 treatments for SIS. Baseline and posttreatment pain quality scores were graphed to provide a visual representation of treatment-associated changes. Analyses of variance were used to examine the differences between treatment conditions in changes in pain quality with treatment.

RESULTS

Both treatments resulted in substantial (and similar) pretreatment to posttreatment improvements in many pain qualities. However, differences in the time course of treatment effects were observed for itchy and heavy qualities.

DISCUSSION

Although 2 different pain treatments appear to have the same effects when only pretreatment to posttreatment changes are examined, treatment differences emerged when the time course of treatment is examined. The findings support the importance of assessing both pain qualities and time course of treatment as outcome domains. The results illustrate how investigators can use data from clinical trials to provide a more fine-tuned description of treatment effects, providing knowledge that could be helpful in selecting treatment options at the individual patient level.

SUMMARY

Examination of the effects of pain treatments on pain qualities over time will help researchers and clinicians understand if certain pain quality domains respond faster to one treatment versus another, and may identify differences between treatments that would not be observed by measures of global pain intensity alone.

A systematic review of therapeutic interventions to reduce acute and chronic post-surgical pain after amputation, thoracotomy or mastectomy

Background

Perioperative neuropathic pain is under-recognized and often undertreated. Chronic pain may develop after any routine surgery, but it can have a far greater incidence after amputation, thoracotomy or mastectomy. The peak noxious barrage due to the neural trauma associated with these operations may be reduced in the perioperative period with the potential to reduce the risk of chronic pain.

Databases and data treatment

A systematic review of the evidence for perioperative interventions reducing acute and chronic pain associated with amputation, mastectomy or thoracotomy.

Results

Thirty-two randomized controlled trials met the inclusion criteria. Gabapentinoids reduced pain after mastectomy, but a single dose was ineffective for thoracotomy patients who had an epidural. Gabapentinoids were ineffective for vascular amputees with pre-existing chronic pain. Venlafaxine was associated with less chronic pain after mastectomy. Intravenous and topical lidocaine and perioperative EMLA (eutectic mixture of local anaesthetic) cream reduced the incidence of chronic pain after mastectomy, whereas local anaesthetic infiltration appeared ineffective. The majority of the trials investigating regional analgesia found it to be beneficial for chronic symptoms. Ketamine and intercostal cryoanalgesia offered no reduction in chronic pain. Total intravenous anaesthesia (TIVA) reduced the incidence of post-thoracotomy pain in one study, whereas high-dose remifentanil exacerbated chronic pain in another.

Conclusions

Appropriate dose regimes of gabapentinoids, antidepressants, local anaesthetics and regional anaesthesia may potentially reduce the severity of both acute and chronic pain for patients. Ketamine was not effective at reducing chronic pain. Intercostal cryoanalgesia was not effective and has the potential to increase the risk of chronic pain. TIVA may be beneficial but the effects of opioids are unclear.