Differences In Pain Responses Research Articles

Oral Sucrose and “Facilitated Tucking” for Repeated Pain Relief in Preterms: A Randomized Controlled Trial

To test the comparative effectiveness of 2 nonpharmacologic pain-relieving interventions administered alone or in combination across time for repeated heel sticks in preterm infants. A multicenter randomized controlled trial in 3 NICUs in Switzerland compared the effectiveness of oral sucrose, facilitated tucking (FT), and a combination of both interventions in preterm infants between 24 and 32 weeks of gestation. Data were collected during the first 14 days of their NICU stay. Three phases (baseline, heel stick, recovery) of 5 heel stick procedures were videotaped for each infant. Four independent experienced nurses blinded to the heel stick phase rated 1055 video sequences presented in random order by using the Bernese Pain Scale for Neonates, a validated pain tool. Seventy-one infants were included in the study. Interrater reliability was high for the total Bernese Pain Scale for Neonates score (Cronbach's α: 0.90-0.95). FT alone was significantly less effective in relieving repeated procedural pain (P < .002) than sucrose (0.2 mL/kg). FT in combination with sucrose seemed to have added value in the recovery phase with lower pain scores (P = .003) compared with both the single-treatment groups. There were no significant differences in pain responses across gestational ages. Sucrose with and without FT had pain-relieving effects even in preterm infants of <32 weeks of gestation having repeated pain exposures. These interventions remained effective during repeated heel sticks across time. FT was not as effective and cannot be recommended as a nonpharmacologic pain relief intervention for repeated pain exposure.

Time of Admission, Gender and Age: Challenging Factors in Emergency Renal Colic - A Preliminary Study

BackgroundNephrolithiasis is a relatively common problem and a frequent Emergency Department (ED) diagnosis in patients who present with acute flank/abdominal pain. The pain management in these patients is often challenging.ObjectivesTo investigate the most effective dose of morphine with the least side effects in emergency renal colic patients.Materials and Methods150 renal colic patients who experienced a pain level of 4 or greater, based on visual analog scale (VAS) at admission time were included. Pain was scored on a 100 mm VAS (0 = no pain, 100 = the worst pain imagined). When patients arrived at ED, a physician would examine the patients and assessed initial pain score, then filled a questionnaire according to the patient information. Patients were assigned to receive 2.5 mg morphine sulfate intravenously. We monitored patients’ visual analog scale (VAS), and adverse events at different time points (every 15 minutes) for 90 minutes. Additional doses of intravenous morphine (2.5 mg) were administered if the patient still had pain. (Max dose: 10 mg). The cumulative dose of morphine, defined as the total amount of morphine prescribed to each patient during the 90 minutes of the study, was recorded. Patients were not permitted to use any nonsteroidal anti-inflammatory drugs as coadjuvant analgesics during the study period. Subjects with inadequate pain relief at 90 minutes received rescue morphine and were excluded from the study. The primary end point in this study was pain relief at 90 minutes, defined as either VAS<40 or decrease of 50% or more as compared to the initial VAS. The secondary objective was to detect the occurrence of adverse effects at any time points in ED.ResultsThe studied patients consisted of 104 men and 46 women with the mean age of 43 ±14 years (range, 18 to 75 years). There was no statistically significant difference between the mean age and gender differences in pain response. Rescue analgesia at 30 minutes were given in 54.5% receiving morphine. The average time to painless was 35 minutes. But there were no statistically significant differences between the mean age and gender differences in pain response (P > 0.05). Older patients responded sooner to morphine than the young. Most of the patients had a pain score of 90 -100 (77.3 %) at the beginning that was reduced to 29.4% during the 30 minutes follow up. During the first hour, we found that 94.7% of the patients had no pain or significant pain reduction and only 2.1% of the patients still had pain.ConclusionsWe conclude that there were no significant differences among the gender, time of admission and side - effects in renal colic patients in response to morphine.

Experimental pressure-pain assessments: Test–retest reliability, convergence and dimensionality

Introduction Experimental pain studies can provide unique insight into the dimensions of pain and into individual differences in pain responsiveness by controlling different aspects of pain-eliciting stimuli and pain measures. In experimental pain studies, pain responsiveness can be assessed as pain threshold, pain tolerance or pain ratings. The test-theoretical qualities of these different measures, however, have not yet been completely documented. In the current study, several of these qualities were investigated in a pain experiment applying different algometric techniques. The objective of the study was to investigate the reliability (test–retest) and the convergent validity (correspondence) of the different methods found in the literature of measuring pressure-pain threshold, and the interrelationship between pressure-pain threshold, pressure-pain tolerance, and pressure-pain ratings. Methods Sixty-six healthy female subjects were enrolled in the study. All pressure stimuli were applied by a trained investigator, using a digital algometer with a 1 cm 2 rubber tip. Pressure-pain thresholds were assessed repeatedly on six different body points (i.e. left and right calf one third of total calf muscle length below the popliteal space), the lower back (5 cm left and right from the L3), and left and right forearm (thickest part of brachioradialis muscle). Next, pressure-pain tolerance was measured on the thumbnail of the non-dominant hand, followed by rating affective and sensory components (on visual analogue scales) of a stimulus at tolerance level. Last, affective and sensory ratings were obtained for two pressure intensities. Results With intraclass correlations above .75 for pain responses per body point, test–retest reliability was found to be good. However, values obtained from all first measurements were significantly higher as compared with the two succeeding ones. Convergent validity of pain thresholds across different body points was found to be high for all combinations assessed (Cronbach's alpha values >.80), but the highest for bilateral similar body parts (>.89). Finally, principal components analysis including measures of threshold, tolerance and pain ratings yielded a three-factor solution that explained 81.9% of the variance: Moderate-level stimulus appraisal & pain tolerance; Pain threshold; Tolerance-level stimulus appraisal. Conclusion and implications Findings of the current study were used to formulate recommendations for future algometric pain studies. Concerning pressure-pain threshold, it is recommended to exclude first measurements for every body point from further analyses, as these measurements were found to be consistently higher compared with the following measurements. Further, no more than two consecutive measurements (after the first measurement) are needed for a reliable mean threshold value per body point. When combining threshold values of several body points into one mean-aggregated threshold value, we suggest to combine bilateral similar points, as convergent validity values were highest for these combinations. The three-factor solution that was found with principal components analyses indicates that pressure-pain threshold, subjective ratings of moderate intensity stimuli, and subjective ratings of the maximum (tolerance) intensity are distinct aspects of pain responsiveness. It is therefore recommended to include a measure of each of these three dimensions of pain when assessing pressure pain responsiveness. Some limitations of our study are discussed.

166: Does penile ring block anesthesia make a difference in pain response to Neonatal circumcision?

166: Does penile ring block anesthesia make a difference in pain response to Neonatal circumcision?

165: Serum biomarker glial fibrillary acidic protein in the identification of periventricular white matter injury in preterm neonates with intraventricular hemorrhage at birth

165: Serum biomarker glial fibrillary acidic protein in the identification of periventricular white matter injury in preterm neonates with intraventricular hemorrhage at birth

Sex Differences in Pain Responses at Maturity Following Neonatal Repeated Minor Pain Exposure in Rats

There is mounting evidence of long-lasting changes in pain sensitivity in school-age children who were cared for in a neonatal intensive care unit. Such care involves multiple pain exposures, 70% of which are accounted for by heel lance to monitor physiological well-being. The authors sought to model the repeated brief pain resulting from heel lance by administering repeated paw needle stick to neonatal rat pups. Repeated needle stick during the first 8 days of life was sex-specific in altering responses to mechanical and inflammatory stimuli, but not to a thermal stimulus, at maturity. Specifically, neonatal paw needle stick males exhibited significantly greater mechanical sensitivity in response to von Frey hair testing, whereas neonatal paw needle stick females exhibited significantly greater pain behavior scores following hindpaw formalin injection. This is the first study to show such sex-dependent changes in pain responsiveness at maturity in animals having experienced repeated neonatal needle stick pain. These findings support existing evidence that there are long-term sensory sequelae following neonatal pain experiences in rats and further suggest that there are sex-linked differences in the nature of the consequences. If these relationships hold in humans, these findings suggest that even mild painful insults early in life are not without sensory consequences.

Ethnic differences in experimental pain perception

A growing body of literature in experimental pain studies suggests important ethnic differences in pain responses. However, a majority of the studies only compared African Americans with Caucasians. The purpose of the present study is to explore ethnic differences in experimental pain outcomes across multiple groups. 119 healthy undergraduate students (23 Asian, 25 African American, 37 Caucasian, and 34 Hispanic) underwent a cold-pressor task (5°C +0.1). It was found that African Americans had a significantly lower pain tolerance (M = 63.2) than both Caucasians (M= 148.92, p=.003) and Asians (M= 132.57, p= .03).

Ethnicity, Catastrophizing, and Qualities of the Pain Experience

It is generally well established that catastrophizing exerts a potent influence on individuals' experience of pain and accompanying emotional distress. Further, preliminary evidence has shown that meaningful differences among various pain relevant outcomes (e.g., pain ratings, endogenous pain inhibitory processes) can be attributed to individuals' ethnic background. The mechanisms that might explain ethnic differences in pain outcomes are unclear, and it remains to be fully established whether the relation between ethnicity and pain response may be indirectly affected by pain catastrophizing. In the current study, we examined differences in pain responses by ethnicity among healthy, young adults (N=62), and attempted to determine whether such an ethnicity-pain relation was mediated by catastrophizing using the standard Pain Catastrophizing Scale (PCS) and a modified version of the PCS reflecting situational catastrophizing during a cold pressor task. Results showed that pain responses varied by ethnicity, as did reported catastrophizing. Catastrophizing mediated the relation between ethnicity and affective and sensory pain responses. To better explicate our findings, we described the context in which these findings occurred following a "who, what, where, when, and why" approach. This approach provides an efficient description of how our findings align with previous research, while identifying future research that should clarify the theoretical underpinnings of catastrophizing and pain and also inform clinical intervention.

Percutaneous vertebroplasty in 1,253 levels: results and long-term effectiveness in a single centre

Several authors claim that vertebroplasty (PVT) is a successful technique, but long-term effectiveness is still debated. Our goal was to evaluate the effectiveness of PVT in patients with symptomatic vertebral fractures that had not responded to conservative treatment. In our centre, 624 patients with 1,253 compression fractures were treated by PVT. Imaging studies, clinical visits and short- and long-term follow-up were assessed by visual analogue scale (VAS) testing of pain. Statistical analysis was performed to evaluate pain response after PVT (paired two-tailed t-test) and to assess any differences in pain due to different lesions (ANOVA test). We found a statistically significant improvement in the patients' quality of life, particularly in pain (P < 0.001). The average VAS value pre-PVT was 8.0 +/- 2.5, which significantly dropped to 1.5 +/- 0.4 by 12 months. There were no significant differences in pain response between the groups of patients with different underlying disease. There was a low complication rate in our study. PVT should be considered the treatment of choice in vertebral fractures with refractory pain. With strict evaluation of the clinical indications and sub-specialised operators, long-term effectiveness is probable.

Pain behaviours in Extremely Low Gestational Age infants

Background To date, there are over 40 infant pain measures. Despite this plethora of measures, only 8 have included preterm infants and only 2 have included Extremely Low Gestational Age (ELGA; infants < 28 weeks GA) in their development. Without reliable, valid and clinically useful indicators for procedural pain in ELGA infants, clinicians have no means to interpret the responses from an immature infant who may respond differently from infants of older GA. Objective To examine the physiological, behavioural and biochemical responses to painful and non-painful procedures in ELGA infants and the influence of GA and sex. Design/methods A prospective crossover design with 50 ELGA infants from one Canadian tertiary level NICU was conducted. Infants were assessed in random order during standardized painful (heel lance) and non-painful (diaper change) procedures. Physiological (heart rate, oxygen saturation) and behavioural (facial and body movement) indicators were continuously collected during 4 phases of the procedures. Biochemical (salivary cortisol) indicators were collected immediately before and 20 min following the procedures. Results Four facial actions (brow bulge, eye squeeze, nasolabial furrow, vertical mouth stretch) increased immediately following the heel lance. There were no specific changes in physiological, body movement or cortisol indicators following the heel lance. ELGA infants demonstrated greater body movements during the diaper change, which may reflect immature motor coordination. No differences in pain responses were found for infants born between 23-25 6/7 weeks GA and those between 26-28 weeks GA. Similarly, no gender differences were found. Conclusions Changes in 4 facial actions were the most sensitive indicators of pain in ELGA infants. This finding is consistent with existing measures where facial actions are the most prominent pain indicators. Specific body movements such as those included in NIDCAP, may provide more information about pain in ELGA infants. Movements such as hand-on-face, finger splaying, fisting, arching or yawning need to be examined in future research.

Satisfaction With Quality of Life Poststroke: Effect of Sex Differences in Pain Response

Bergés I-M, Ottenbacher KJ, Kuo Y-F, Smith PM, Smith D, Ostir GV. Satisfaction with quality of life poststroke: effect of sex differences in pain response. Objective To study the relationship between sex differences among men and women in the response to pain and the effect on satisfaction with quality of life (QOL) in poststroke patients approximately 90 days after discharge from inpatient medical rehabilitation. Design Cross-sectional design. Setting Community based. Participants The sample included 1724 patients (877 men, 847 women) aged 40 years and older with a history of stroke, according to information obtained from the IT HealthTrack database. The average age was 68.7 years; 79.3% were non-Hispanic white. Interventions Not applicable. Main Outcome Measure Satisfaction with QOL. Results Pain ratings for both the men and the women were significant and inversely associated with satisfaction with QOL after adjustments for possible confounding factors. However, among men with stroke, each 1-point increase in pain rating was associated with an 18% decreased odds of being satisfied with QOL (odds ratio [OR], .81; 95% confidence interval [CI], .77–.86). Conversely, among women with stroke, each 1-point increase in pain rating was associated with an 11% decreased odds of being satisfied with QOL (OR=.89; 95% CI, .84–.95). Conclusions Our data indicate that pain after stroke is significantly associated with reduced satisfaction with QOL, particularly among men. Increased awareness and treatment of pain may improve satisfaction with QOL. Our findings suggest that sex differences and pain response are clinically important factors in examining satisfaction with QOL in the poststroke population.

Ethnic identity predicts experimental pain sensitivity in African Americans and Hispanics

The aim of this study was to examine experimental pain sensitivity in three ethnic groups, African Americans, Hispanic Americans and non-Hispanic White Americans, and to determine whether ethnic identity is differentially associated with pain sensitivity across ethnic groups. Participants included sixty-three African American, sixty-one Hispanic and eighty-two non-Hispanic white participants who were assessed using three experimental pain measures: thermal, cold-pressor and ischemic. Participants’ ethnic identity was assessed using the Multi-group Ethnic Identity Measure (MEIM). Ethnic group differences in pain responses were observed, with African American and Hispanic subjects showing lower cold and heat pain tolerances than non-Hispanic White Americans. In addition, pain range (i.e. tolerance-threshold) was computed for heat, cold and ischemic pain, and the two minority groups again had lower values compared to non-Hispanic White Americans. Ethnic identity was associated with pain range only for African American and Hispanic groups. Statistically controlling for ethnic identity rendered some of the group differences in pain range non-significant. These findings indicate that ethnic identity is associated with pain sensitivity in ethnic minority groups, and may partially mediate group differences in pain perception. The results of the present investigation provide evidence of ethnic group differences in responses to experimental pain across multiple noxious stimuli, with both minority groups exhibiting greater sensitivity to laboratory evoked pain compared to non-Hispanic White Americans.

Gap in Dental Care Can Lead to Diabetes, Other Disease Conditions

Gap in Dental Care Can Lead to Diabetes, Other Disease Conditions

Sex, Gender, and Age: Contributions to Laboratory Pain Responding in Children and Adolescents

A cross-sectional design across late childhood and adolescence examined the influence of sex, gender socialization, and age on responses to controlled laboratory pain tasks. Healthy children and adolescents (n = 240, 50% female, age 8 to 18 years) completed the Child Sex Role Inventory, a self-report measure of identification with stereotypically masculine and feminine personality traits, as an index of gender socialization and participated in pressure, cold pressor, and heat pain tasks. Pain tolerance, pain intensity, and bothersomeness of each pain task were assessed. Masculinity correlated with lower heat pain ratings in boys but not girls. Logistic regression indicated cold pain intensity ratings were predicted by sex, gender score, and the age-by-gender score interaction. Heat pain intensity was predicted by age, gender score, age-by-gender score interaction, and sex-by-gender score. Perspective The current findings support closer examination of the influence of gender socialization on young people’s pain responses and highlight the importance of a multifactorial, developmental approach to studying the impact of gender socialization on the emergence of sex differences in pain responses after puberty.

(907): Relationship of ethnicity and coping style to laboratory pain stimuli among healthy children

Ethnic-related differences in pain in adults have been documented: African-Americans report higher levels of clinical pain and show greater experimental pain sensitivity compared to Caucasians. However, the possible moderating effect of coping style on this relationship has received less attention and few studies have included children. We examined healthy children’s responses to laboratory pain tasks (cold pressor, thermal heat, and pressure) and the contribution of coping style to ethnic differences in pain responses.

Heart rate mediation of sex differences in pain tolerance in children

Despite evidence supporting the existence of important sex-related differences in pain, the mechanisms underpinning such differences are not well understood. The aim of this study is to examine the relationship between sex and pubertal differences in autonomic arousal and pain tolerance to laboratory pain stimuli in healthy children. We tested the following specific hypotheses: (1) females would have greater autonomic arousal and less pain tolerance than males, and (2) this sex difference in pain tolerance would be mediated by autonomic arousal. Participants were 244 healthy children (50.8% female, mean age 12.73±2.98 years, range 8–18 years). Separate 4-trial blocks of cutaneous pressure and thermal pain stimuli were presented in counterbalanced order. Heart rate (HR) was recorded during 2–3 min periods preceding each block and a 1-min period between trials. Results indicated lower tolerance in females for cutaneous pressure, but not thermal pain, compared to males. In addition, pre-trial HR was greater for females than males. Mediation analyses suggested that sex differences in pressure pain tolerance were accounted for by sex differences in pre-trial HR. There were also significant effects for puberty, but these did not vary by sex. Overall, early pubertal children had greater pre-trial HR and less pain tolerance than those in late puberty for both cutaneous pressure and thermal pain across sex. These results suggest that autonomic arousal may be a mediator of sex-related differences in pain responses in children.

Individual differences in pain responses

The experience of pain is characterized by tremendous inter-individual variability. Indeed, an identical noxious stimulus can produce vastly different pain responses across individuals. Historically, scientists have regarded this variability as a nuisance; however, substantial data suggest that these individual differences may provide valuable information that can be used to enhance clinical management of pain. This paper discusses several factors that contribute to individual differences in pain perception, including demographic (ie, sex, age, and ethnicity), genetic, and psychosocial variables. These factors are discussed in the context of the biopsychosocial model of pain, which posits that pain perception is influenced by interactions among biologic, psychosocial, and sociocultural factors. Finally, the clinical and scientific implications of individual differences in pain are discussed.

Breast cancer patients have better outcomes than prostate cancer patients for palliation of painful bone metastases: Results of RTOG 97–14

6073 Background: It is unclear whether there are gender-based differences in pain response and survival after palliative external beam radiotherapy (XRT) for painful bone metastases from breast or prostate cancers. Methods: RTOG and NCCTG conducted a randomized, prospective phase III study of XRT for patients with breast or prostate cancer and painful bone metastases (Brief Pain Index (BPI) worst pain score of ≥5 out of 10). Patients were randomized to 8 Gy in a single fraction vs. 30 Gy in 10 fractions, stratified by number of painful sites, weight bearing site, worst pain score and bisphosphonate usage. Results of the primary study are reported elsewhere; XRT was very effective, providing pain relief in 66% of patients. At 3 months follow-up, there was no difference between the two treatment arms, regardless of stratification. Results: In this gender-based analysis, there were 453 women with breast cancer and 445 men with prostate cancer; median age was 58 and 71 years, respectively. Stratification variables were balanced other than more women received bisphosphonates (46% vs 8% of men). Pain relief was evaluated at 3 months using the BPI. For breast and prostate cancer, complete response was seen in 17% and 16% and partial response in 54% and 43% for an overall response rate of 71% and 59% (p=0.0034) Median survival on the 30 Gy arm for women was 11.6 months compared to 7.3 months for men and median survival on the 8 Gy arm for women was 12.5 months compared to 7.9 months for men. Separate multivariate analyses of the 30 Gy arm and 8 Gy arm, showed that women with breast cancer had statistically significantly longer survival compared to men with prostate cancer (30Gy: HR 1.78, p-value <0.0001; 8Gy: HR 1.75, p-value < 0.0001), after adjusting for age (which was not significant) and KPS. Conclusions: Women with bone metastases from breast cancer experience better outcomes in terms of pain control and survival compared to men with prostate cancer with bone mets treated with palliative radiotherapy. Further consideration should be given to tailoring treatment by gender. Acknowledgment: This trial was supported by NCI grants RTOG U10 CA21661, CCOP U10 CA37422, and Stat U10 CA32115. No significant financial relationships to disclose.

Observations on the management of acute pain crisis in adult sickle cell disease in eastern Saudi Arabia.

BACKGROUNDSickle cell pain crisis continues to challenge patients and health professionals in places like Saudi Arabia, where the disease is common, and use of narcotic analgesics is strictly controlled. We sought to find the most effective and appropriate pain control regime for adult sickle cell pain crisis in Saudi Arabian patients.PATIENTS AND METHODSAdult sickle cell disease patients in crisis, treated initially in the emergency room of a private health center, usually undergo further treatment with different pain control regimes in an observation ward. We compared the adequacy of pain conrol during the three recent years (2000–2002) with those of the preceding three (1995–1997).RESULTSTreatment with regular opiates supplemented with oral analgesics during the second three-year period produced better results than “on demand” regimes. The former regimen enabled about 83% of patients from the second three-year period to be discharged home within two days compared with 71% during the first three-year period (P<0.05). A minority of patients needed more time for pain resolution. Patient response to oral analgesics was variable and females appeared to fare better than males.DISCUSSIONGreater empathy and individualized treatment are required for sickle cell pain crisis patients because of their variable clinical presentation, response to medications, and the regularity of pain in their lives. The observed gender differences in pain response require further study.

Analgesic Comparison of Meloxicam or Ketoprofen for Orthopedic Surgery in Dogs

To compare the safety and efficacy of 2 analgesic protocols (preoperative meloxicam or intraoperative ketoprofen administration) during the first 24 hours after orthopedic surgery in dogs. Double-blind, prospective randomized clinical trial. Sixty client-owned dogs. Dogs with surgical orthopedic disorders were randomly separated into 2 groups: 30 dogs were administered 0.2 mg/kg meloxicam intravenously (IV) immediately before induction and 30 dogs were administered 2 mg/kg ketoprofen IV, 30 minutes before the end of surgery. Pain was assessed with a visual analog scale (VAS) and a cumulative pain score (CPS) preoperatively and at 30 minutes, 1, 2, 3, 4, 6, 8, and 24 hours after extubation. Selected serum biochemical variables were measured before and 24 hours after surgery and, buccal mucosal bleeding time (BMBT) and whole blood clotting time (WBCT) were measured before and 8 hours after surgery. Dogs were anesthetized with propofol and maintained on halothane in oxygen. Any complications were documented for 7 days after surgery. Results were compared between the 2 groups for significant differences in VAS scores (2-sample t-test) and in CPS (Wilcoxon's 2-sample test). Moreover, results were analyzed for significant differences in area under the curve (AUC) for VAS (2-sample t-test) and CPS (Wilcoxon's 2-sample test) among groups. To assess the effects of treatments on biochemical and coagulation functions, pre- and postoperative mean values of BMBT and WBCT were compared within both treatment groups (paired t-tests) and between both groups (2-sample t-test). No significant differences in pain response or coagulation were found between meloxicam- and ketoprofen-treated dogs. In both groups, alkaline phosphatase and alanine aminotransferase concentrations were significantly increased compared with baseline. No serious complications occurred. Preoperative administration of meloxicam is a safe and effective method of controlling postoperative pain for up to 24 hours in dogs undergoing orthopedic surgery. Analgesia after administration of preoperative meloxicam was comparable with administration of ketoprofen at the end of the surgery.