Improving perioperative pain management: a preintervention and postintervention study in 7 developing countries.

INTRODUCTION: The burden of untreated postoperative pain is high. OBJECTIVE: This study assessed feasibility of using quality improvement (QI) tools to improve management of perioperative pain in hospitals in multiple developing countries. METHODS: The International Pain Registry and Developing Countries working groups, from the International Association for the Study of Pain (IASP), sponsored the project and PAIN OUT, a QI and research network, coordinated it, and provided the research tools. The IASP published a call about the project on its website. Principal investigators (PIs) were responsible for implementing a preintervention and postintervention study in 1 to 2 surgical wards in their hospitals, and they were free to choose the QI intervention. Trained surveyors used standardized and validated web-based tools for collecting findings about perioperative pain management and patient reported outcomes (PROs). Four processes and PROs, independent of surgery type, assessed effectiveness of the interventions. RESULTS: Forty-three providers responded to the call; 13 applications were selected; and PIs from 8 hospitals, in 14 wards, in 7 countries, completed the study. Interventions focused on teaching providers about pain management. Processes improved in 35% and PROs in 37.5% of wards. CONCLUSIONS: The project proved useful on multiple levels. It offered PIs a framework and tools to perform QI work and findings to present to colleagues and administration. Management practices and PROs improved on some wards. Interpretation of change proved complex, site-dependent, and related to multiple factors. PAIN OUT gained experience coordinating a multicentre, international QI project. The IASP promoted research, education, and QI work.

Prospective evaluation of chronic pain disorders and treatments.

BACKGROUND: The incidence of chronic pain is variable among individuals who have sustained traumatic or surgical injury. Also, treatments for pain rarely are effective consistently for a procedure or agent, and no therapies are considered effective for pain that is chronic. NEW METHOD: Difficulties with standard methods for conducting clinical trials call attention to a need for protocols that provide a new understanding of the development of and control over chronic pain. Prospective single-subject research designs can document varieties of pain progression over time for individuals. Subsequent grouping of individuals with common characteristics directs a mechanism-based approach to therapy. RESULTS: Tracking of individuals' pain and associated influences over time is consistent with clinical practice, noting and adapting to changes that occur. COMPARISON WITH EXISTING METHODS: Grouping patients with diverse characteristics and variable effects of therapy is problematic. Conventional evaluation of pain assesses patients with similar injuries or surgery without characterizations of individuals who develop chronic pain or recover over time. Also, classical evaluation of therapies involves comparison of groups receiving treatment or a placebo without characterization of patients with successful and unsuccessful results. CONCLUSIONS: Single-subject prospective studies can inform clinical trials according to individual differences that would be obscured by comparison of groups with unknown variation in characteristics that influence pain and therapeutic effectiveness.

The Transition of Acute Postoperative Pain to Chronic Pain: An Integrative Overview of Research on Mechanisms.

The nature of the transition from acute to chronic pain still eludes explanation, but chronic pain resulting from surgery provides a natural experiment that invites clinical epidemiological investigation and basic scientific inquiry into the mechanisms of this transition. The primary purpose of this article is to review current knowledge and hypotheses on the transition from acute to persistent postsurgical pain, summarizing literature on clinical epidemiological studies of persistent postsurgical pain development, as well as basic neurophysiological studies targeting mechanisms in the periphery, spinal cord, and brain. The second purpose of this article is to integrate theory, information, and causal reasoning in these areas. Conceptual mapping reveals 5 classes of hypotheses pertaining to pain. These propose that chronic pain results from: 1) persistent noxious signaling in the periphery; 2) enduring maladaptive neuroplastic changes at the spinal dorsal horn and/or higher central nervous system structures reflecting a multiplicity of factors, including peripherally released neurotrophic factors and interactions between neurons and microglia; 3) compromised inhibitory modulation of noxious signaling in medullary-spinal pathways; 4) descending facilitatory modulation; and 5) maladaptive brain remodeling in function, structure, and connectivity. The third purpose of this article is to identify barriers to progress and review opportunities for advancing the field. This review reveals a need for a concerted, strategic effort toward integrating clinical epidemiology, basic science research, and current theory about pain mechanisms to hasten progress toward understanding, managing, and preventing persistent postsurgical pain. PERSPECTIVE: The development of chronic pain after surgery is a major clinical problem that provides an opportunity to study the transition from acute to chronic pain at epidemiologic and basic science levels. Strategic, coordinated, multidisciplinary research efforts targeting mechanisms of pain chronification can to help minimize or eliminate persistent postsurgical pain.

Central noradrenergic mechanisms and the acute stress response during painful stimulation.

Events that threaten tissue integrity including noxious stimulation activate central noradrenergic circuits, particularly locus coeruleus and its projections. Recent advances in theory hold that an adaptive, defensive shift in brain activity takes place in response to threat. In principle, this shift may accentuate the autonomic and central biomarkers of the perception of painful events and the experience of pain itself. We have examined the effects of an alpha-2 agonist on pupil dilation responses, skin conductance responses, near field somatosensory evoked potentials and pain reports in normal volunteers undergoing repeated trials of painful fingertip stimulation delivered at low, medium and high intensities. In a double-blinded study, 114 healthy male and female volunteers underwent repeated noxious stimulation under baseline, placebo and active drug conditions where the active drug was the alpha-2 agonist tizanidine 4 mg. In contrast to baseline and placebo conditions, tizanidine 4 mg significantly reduced the magnitudes of the mean pupil dilation response, the mean skin conductance response, the mean near field somatosensory evoked potential peak-to-peak amplitude and the mean pain intensity rating. Stimulus intensity significantly altered all three biomarkers and the pain report in a graded fashion. There were no sex differences. These findings support the hypotheses that painful events activate central noradrenergic circuits, and that these circuits play a role in the autonomic and central arousal associated with pain.

Acute pain: effective management requires comprehensive assessment.

Pain is among the most common reasons that patients seek medical care, and inadequate assessment may result in suboptimal management. Acute pain in response to trauma or surgery can be complex, variable, and dynamic, but its assessment is often simplistic and brief. One-dimensional rating scale measures of pain severity facilitate rapid evaluation and often form the basis of treatment algorithms. However, additional features of pain should inform the selection of a treatment regimen, and can include pain qualities, duration, impact on functional capabilities, and underlying cause. Patient age, sex, psychosocial features, and comorbid conditions are also important features to consider. Use of a multidimensional tool is recommended for assessing many of these features if time permits. Additionally, clinicians often fail to recognize or consider the potentially detrimental long-term effects of acute pain. As the United States continues to experience a prescription drug crisis, a "universal precautions" approach including abuse risk assessment and abuse deterrence strategies should be implemented for patients receiving opioids. Increased efforts and research are necessary to enhance the utility of available acute pain assessment tools. Developing more comprehensive tools for patient assessment is the first step in achieving the ultimate goal of effective acute pain management. The objectives of this review are to summarize issues regarding the complexity of acute pain and to provide suggestions for its evaluation.

Quality of postoperative pain management in American versus European institutions.

Management of postoperative pain remains an important clinical problem throughout the world. Using the PAIN-OUT acute pain registry database to examine perioperative pain management in orthopedic surgery patients, we compared patient-reported outcomes (PROs) in a pooled sample obtained from four American hospitals (N = 473) with PROs in a pooled sample of 20 European institutions (N = 8799). Most American hospitals consistently assess acute pain in surgical patients due to Joint Commission accreditation guidelines. Therefore, we hypothesized that this practice would create a climate of clinical staff sensitivity to patients' pain and a greater readiness to intervene when pain is higher than one would find in Europe as a whole. American institutions might then provide better control of postoperative pain after orthopedic surgery than European institutions. Because of the large sample sizes, our analyses focused on effect size rather than statistical significance. Evaluation of the pain PROs revealed that European patients reported much lower Worst Pain on the first day after orthopedic surgery than American patients. The mean Worst Pain (± SD) for Europeans was 5.4 (2.5) but for Americans the mean was 7.4 (2.7), p < .0001, a large effect size. Europeans also reported significantly less emotional discomfort, less interference of pain with activity and lower Least Pain. Nonetheless, 98.3% of American patients received opioids on the ward on the first postoperative day compared to 70.2% of European patients, and 41.1% received regional analgesia on the ward while 15.9% of European patients received regional analgesia (both small effect sizes). Overall, the results are clear in demonstrating much better pain control in the ensemble of European countries as compared to the United States.

Only modest long-term opioid dose escalation occurs over time in chronic nonmalignant pain management.

Clinical experience and the literature increasingly support differentiating chronic pain associated with malignant disease from chronic pain associated with nonmalignant conditions when defining optimal pharmacotherapy. The use of opioids for chronic nonmalignant pain has grown steadily despite the lack of a strong evidence base that can guide practice. A fundamental question is whether patients develop tolerance and need repeated dose escalations to sustain pain control. We examined opioid prescribing data from United Kingdom Clinical Practice Research Datalink longitudinal database of general practice records and tracked dose changes but not pain reports in a sample of 4035 patients who received oral or transdermal-extended release opioids for chronic nonmalignant pain. The median number of days on opioid pharmacotherapy for all patients was 311. Thirty percent of patients never changed doses during the course of treatment. In patients who never changed medications, the mean morphine equivalent 24-hour dose increased from beginning to end of opioid pharmacotherapy only by 1.4 fold, t = 25.73, Cohen's d = .427 and was independent of both age and gender. Comparison across extended release morphine, oxycodone, and fentanyl revealed that it was significantly greatest for patients using fentanyl and least for those using morphine.

Opioid pharmacotherapy for chronic noncancer pain: the american experience.

Chronic noncancer pain is a significant and growing public health challenge in the United States. Lacking effective alternative interventions for effective chronic noncancer pain management, many physicians have turned to opioid pharmacotherapy. Increased opioid prescribing brings not only gains in therapeutic benefit but also a higher incidence of adverse drug events including increased medication misuse and opioid related mortality. Currently the United States must confront the dual problems of widespread undertreated chronic noncancer pain and a prescription opioid abuse crisis. Withholding pain relieving drugs from patients in need is unjustifiable, yet drug diversion, abuse and adverse drug events have become major social as well as medical problems. At the heart of this crisis is the lack of definitive evidence about the risk to benefit ratio of opioid pharmacotherapy for chronic noncancer pain both on an individual case and on a population basis. This article describes the extent and severity of the American chronic noncancer pain problem and the history of opioid pharmacotherapy for chronic noncancer pain in the United States. It then discusses the concept of evidence based practice and reviews current evidence supporting opioid pharmacotherapy for chronic noncancer pain as well as adverse drug events related to opioid pharmacotherapy including misuse and abuse. Finally, it considers the conflict of providing pain relief versus protecting society and reviews steps that governmental agencies, industry and others are taking to contain and ultimately resolve the problems of excessive prescribing and conflicting priorities.

Effects of music engagement on responses to painful stimulation.

OBJECTIVES: We propose a theoretical framework for the behavioral modulation of pain based on constructivism, positing that task engagement, such as listening for errors in a musical passage, can establish a construction of reality that effectively replaces pain as a competing construction. Graded engagement produces graded reductions in pain as indicated by reduced psychophysiological arousal and subjective pain report. METHODS: Fifty-three healthy volunteers having normal hearing participated in 4 music listening conditions consisting of passive listening (no task) or performing an error detection task varying in signal complexity and task difficulty. During all conditions, participants received normally painful fingertip shocks varying in intensity while stimulus-evoked potentials (SEP), pupil dilation responses (PDR), and retrospective pain reports were obtained. RESULTS: SEP and PDR increased with increasing stimulus intensity. Task performance decreased with increasing task difficulty. Mixed model analyses, adjusted for habituation/sensitization and repeated measures within person, revealed significant quadratic trends for SEP and pain report (Pchange<0.001) with large reductions from no task to easy task and smaller graded reductions corresponding to increasing task difficulty/complexity. PDR decreased linearly (Pchange<0.001) with graded task condition. We infer that these graded reductions in indicators of central and peripheral arousal and in reported pain correspond to graded increases in engagement in the music listening task. DISCUSSION: Engaging activities may prevent pain by creating competing constructions of reality that draw on the same processing resources as pain. Better understanding of these processes will advance the development of more effective pain modulation through improved manipulation of engagement strategies.

Postoperative pain trajectories in cardiac surgery patients.

Poorly controlled postoperative pain is a longstanding and costly problem in medicine. The purposes of this study were to characterize the acute pain trajectories over the first four postoperative days in 83 cardiac surgery patients with a mixed effects model of linear growth to determine whether statistically significant individual differences exist in these pain trajectories, and to compare the quality of measurement by trajectory with conventional pain measurement practices. The data conformed to a linear model that provided slope (rate of change) as a basis for comparing patients. Slopes varied significantly across patients, indicating that the direction and rate of change in pain during the first four days of recovery from surgery differed systematically across individuals. Of the 83 patients, 24 had decreasing pain after surgery, 24 had increasing pain, and the remaining 35 had approximately constant levels of pain over the four postoperative days.

Resolution of acute pain following discharge from the emergency department: the acute pain trajectory.

UNLABELLED: We demonstrate and evaluate a method for modeling acute pain resolution in individual patients over 6 days following an emergency department visit for an acutely painful condition. Five hundred and thirteen patients presenting with acutely painful conditions provided 11-point numerical ratings of pain intensity at discharge from an emergency department and daily thereafter for a total of 6 days. Latent growth curve modeling with a linear fit yielded measures of initial pain intensity (intercept) and rate of pain resolution (slope) for each individual patient. The linear fits provided good approximations of individual pain trajectories. The average patient had intercept of 6.57 with a slope of -.61. On Day 4, 54.6% of patients reported a pain level equal to or greater than 4. Classification of individual patients by slope revealed that 79% of the sample had the expected negative slope for acute pain resolution while 21% had flat or positive slopes, indicating lack of pain resolution or worsening of pain over time following discharge. The standard errors of measurement for the acute pain trajectories were markedly smaller than those for conventional pain ratings, indicating that the trajectory approach to pain measurement improves measurement precision. PERSPECTIVE: The acute pain trajectory provides more information than conventional pain measurement and increases measurement precision. It provides a means of determining the efficacy of acute pain management in the emergency department. The rate of pain resolution is a potentially valuable outcome measure for controlled clinical trials.

Individual differences in the effects of music engagement on responses to painful stimulation.

UNLABELLED: Engaged attention, including music listening, has shown mixed results when used as a method for reducing pain. Applying the framework of constructivism, we extend the concept of engagement beyond attention/distraction to include all cognitive and emotional/motivational processes that may be recruited in order to construct an alternative experience to pain and thus reduce pain. Using a music-listening task varying in task demand, we collected stimulus-evoked potentials, pupil dilation, and skin conductance responses to noxious electrocutaneous stimulations as indicators of central and peripheral arousal, respectively. Trait anxiety (Spielberger State-Trait Anxiety Inventory) and absorption (Tellegen Absorption Scale) provided indicators of individual differences. One hundred and fifty-three healthy, normal volunteers participated in a test session in which they received 3 stimulus intensity levels while listening to background tones (No Task) or performing a music-listening task. Linear slopes indicating net engagement (change in stimulus arousal relative to task performance) decreased with increasing task demand and stimulus level for stimulus-evoked potentials. Slopes for pupil dilation response and skin conductance response varied with task demand, anxiety, and absorption, with the largest engagement effect occurring for high anxiety/high absorption participants. Music engagement reduces pain responses, but personality factors like anxiety and absorption modulate the magnitude of effect. PERSPECTIVE: Engaging in music listening can reduce responses to pain, depending on the person: people who are anxious and can become absorbed in activities easily may find music listening especially effective for relieving pain. Clinicians should consider patients' personality characteristics when recommending behavioral interventions like music listening for pain relief.

Postoperative pain trajectories in chronic pain patients undergoing surgery: the effects of chronic opioid pharmacotherapy on acute pain.

UNLABELLED: For 2 weeks following surgery, 55 patients with preexisting chronic pain (CP) reported daily postoperative pain with movement and at rest. Of these, 30 CP patients used opioid pharmacotherapy for CP management and 25 did not. We modeled pain resolution in each patient using a linear fit so that each patient yielded 2 scores for each pain rating: 1) an intercept, or initial level of pain, immediately after surgery; and 2) a slope, or rate of pain resolution. The patients not using opioid pharmacotherapy had a mean pain with movement intercept of 5.4 and a slope of -.20, while the patients using opioid pharmacotherapy had a significantly higher mean intercept of 7.68 (P = .001) and a slope of -.21, sustaining higher pain levels over days. The opioid pharmacotherapy patients had the same rate of pain resolution as the other CP patients, and both groups resolved their pain more slowly than normal surgery patients. Preexisting CP may predispose a patient undergoing surgery to a slower rate of postoperative pain resolution. Chronic pain patients who use opioids share this predisposition but in addition, they are at risk for markedly higher postoperative pain across the entire pain resolution trajectory. PERSPECTIVE: This is an observational rather than a randomized controlled study, and as such is less definitive. Nonetheless, these findings are consistent with those of animal studies showing that prolonged exposure to opioids can produce opioid-induced hyperalgesia. Patients with opioid pharmacotherapy for chronic pain who undergo surgery merit special attention for acute pain management.

Improving individual measurement of postoperative pain: the pain trajectory.

UNLABELLED: The purpose of this study was to demonstrate a method for increasing the precision and information yield of postoperative pain assessment. We recorded pain intensity ratings over 6 days after surgery in 502 elective surgery patients and examined individual pain trajectories. A linear fit of an individual patient's scores defines a trajectory with two features: (1) the intercept or initial pain intensity; and (2) the slope, or rate of pain resolution. Three pain trajectory patterns emerged from examination of the pain trajectory slopes. Most patients (63% of the sample) demonstrated a negative slope trajectory characterized by a decline in pain intensity over days after surgery. Other patients (25% of the sample) demonstrated a flat trajectory with no meaningful change over 6 days from pain they reported initially. A third patient group (12% of the sample) had a positive slope trajectory in which pain scores increased over 6 days after surgery. Measures derived from individual pain trajectories yielded much lower standard errors of measurement and therefore had better measurement precision than did conventional pain assessment methods. Pain trajectory measures proved sufficiently precise to characterize pain patterns reliably in individual patients. PERSPECTIVE: Progress in acute pain management requires effective pain assessment. The acute pain trajectory quantifies rate of pain resolution as well as pain intensity. It affords more precise measurement than conventional pain assessment and can identify abnormal postoperative pain resolution.

Interview: Reflections on pain research and management: past, present and future.

C Richard Chapman is Professor and Director of the Pain Research Center in the department of Anesthesiology at the University of Utah, Salt Lake City (UT, USA). A psychologist and psychophysiologist, he has worked in the pain research field since 1970. He spent 29 years at the University of Washington before coming to the University of Utah. His interests span acute pain, chronic pain, cancer pain and pain measurement.

Opioid pharmacotherapy for chronic non-cancer pain in the United States: a research guideline for developing an evidence-base.

UNLABELLED: This document reports the consensus of an interdisciplinary panel of research and clinical experts charged with reviewing the use of opioids for chronic noncancer pain (CNCP) and formulating guidelines for future research. Prescribing opioids for chronic noncancer pain has recently escalated in the United States. Contrasting with increasing opioid use are: 1) The lack of evidence supporting long-term effectiveness; 2) Escalating misuse of prescription opioids including abuse and diversion; and 3) Uncertainty about the incidence and clinical salience of multiple, poorly characterized adverse drug events (ADEs) including endocrine dysfunction, immunosuppression and infectious disease, opioid-induced hyperalgesia and xerostomia, overdose, falls and fractures, and psychosocial complications. Chief among the limitations of current evidence are: 1) Sparse evidence on long-term opioid effectiveness in chronic pain patients due to the short-term time frame of clinical trials; 2) Insufficiently comprehensive outcome assessment; and 3) Incomplete identification and quantification of ADEs. The panel called for a strategic interdisciplinary approach to the problem domain in which basic scientists and clinicians cooperate to resolve urgent issues and generate a comprehensive evidence base. It offered 4 recommendations in 3 areas: 1) A research strategy for studying the effectiveness of long-term opioid pharmacotherapy; 2) Improvements in evidence-generation methodology; and 3) Potential research topics for generating new evidence. PERSPECTIVE: Prescribing opioids for CNCP has outpaced the growth of scientific evidence bearing on the benefits and harms of these interventions. The need for a strong evidence base is urgent. This guideline offers a strategic approach to creating a comprehensive evidence base to guide safe and effective management of CNCP.

Predictability of painful stimulation modulates subjective and physiological responses.

UNLABELLED: Clinical observations suggest that the perceived intensity of a painful event increases as the unpredictability of its occurrence increases. We examined the effect of varying stimulus predictability on the Somatosensory Evoked Potential (SEP), Pupil Diameter Response (PDR), Pain Report (PR), and Fear Report (FR) in 25 healthy female volunteers experiencing repeated noxious fingertip shocks. Each volunteer underwent high- and low-stimulus intensities in 4 stimulus patterns defined by stimulus sequence (SEQ) and interstimulus interval (ISI) as follows: A) serial stimulus intensity SEQ with fixed ISI; B) serial stimulus intensity SEQ with varied ISI; C) random stimulus intensity SEQ with fixed ISI; and D) random stimulus intensity SEQ with varied ISI. Results revealed that: (1) lower stimulus predictability led to higher PR and FR, greater PDR magnitude, and greater SEP amplitude; and (2) the 4 dependent measures showed the same response pattern across levels of stimulus predictability. These findings support the hypothesis that lower stimulus predictability is associated with higher reported pain and fear as well as greater physiological arousal. PERSPECTIVE: Patients undergoing painful procedures experience more distress when the occurrence of a painful event is unpredictable. Poor predictability increases pain, fear, and associated physiological arousal. Maximizing the predictability of painful events may improve the quality of patient care by minimizing associated levels of pain and fear.

Speech motor control and chronic back pain: a preliminary investigation.

OBJECTIVES: Chronic back pain and its sequelae can influence cognitive, affective, and neuromuscular functioning. Speech production--a complex sensorimotor activity--integrates shared cognitive, neuromuscular, and musculoskeletal resources, and therefore could be altered by chronic pain. The purpose of this preliminary investigation was twofold: 1) to determine whether speech alternating motion rates (i.e., speech AMRs) which require rapid, reciprocally coordinated articulatory movements were associated with chronic back pain; and 2) to identify factors that might mediate any observed alterations. DESIGN: Fifty participants, fully or partially disabled by chronic back pain, completed standardized protocols related to pain, depression, disability, medications, as well as speech AMRs. RESULTS: Higher levels of back pain were significantly associated with slower speech AMRs. Stepwise multiple regression assessed the unique and cumulative effects of specific variables such as degree of back pain, depression, level of disability, and medication use on speech motor performance. Speech motor slowness was uniquely related to back pain and the use of nonprescription pain medications, but not to level of depression or disability. CONCLUSIONS: Chronic back pain independently influences speech motor rates. Several explanatory models are proposed including pain-induced centrally mediated motor retardation/inhibition, reduced selective attention, and peripherally based "bracing/holding" of shared musculoskeletal environments.

Postoperative pain patterns in chronic pain patients: a pilot study.

OBJECTIVE: This exploratory investigation compared patterns of postoperative pain over 6 days in normal patients recovering from surgery with those of patients using opioid medications for chronic pain. It tested the following hypotheses: 1) Chronic pain patients have a different pattern of postoperative pain than normals; 2) Women have a different pattern of postoperative pain resolution than men. PATIENTS: Normal (N = 96) and chronic pain (N = 42) patients undergoing surgery served as subjects. DESIGN: The study employed a linear mixed effects model to compare repeated measures of pain in the two patient groups. OUTCOME MEASURES: Patients rated pain daily following surgery over 6 days. Each patient's pain pattern is a linear trend having an intercept (initial pain level) and a slope (rate of pain change over days). RESULTS: The chronic pain patients initially reported a higher mean pain level, and they differed from normal patients in their average postoperative pain patterns (P < 0.001), as did men and women (P = 0.039). Whereas normals decreased in pain report over the 6 days of recovery at an average rate of -0.35 units per day, chronic pain patients changed at an average rate of only -0.06 units per day (P < 0.001). Women began at day 0 with greater average pain than men (6.15 vs 5.16, P = 0.029) but resolved their pain more rapidly (-0.291 points per day vs -0.118 points per day, P = 0.017). CONCLUSIONS: Surgical patients who have chronic pain and use opioid medications for that pain have more postoperative pain than normals and resolve that pain more slowly.