Acute Pain Situations Research Articles

Acute physiological responses and muscle recovery in females: a randomised controlled trial of muscle damaging exercise in hypoxia

BackgroundStudies have investigated the effects of training under hypoxia (HYP) after several weeks in a male population. However, there is still a lack of knowledge on the acute hypoxic effects on physiology and muscle recovery in a female population.MethodsThis randomized-controlled trial aimed to investigate the acute effects of muscle damaging exercise, performed in HYP and normoxia (CON), on physiological responses and recovery characteristics in healthy females. Key inclusion criteria were recreationally active female participants between the age of 18 to 35 years without any previous surgeries and injuries, whilst key exclusion criteria were acute pain situations, pregnancy, and medication intake. The females conducted a muscle-damaging protocol, comprising 5 × 20 drop-jumps, in either HYP (FiO2: 12%) or CON (FiO2: 21%). Physiological responses, including capillary oxygenation (SpO2), muscle oxygenation (SmO2), heart rate (HR), core- (Tcore) and skin- (Tskin) temperature were assessed at the end of each exercise set. Recovery characteristics were quantified by taking venous blood samples (serum creatine-kinase [CK], C-reactive protein [CRP] and blood sedimentation rate [BSR]), assessing muscle swelling of the quadriceps femoris muscle, maximum voluntary isometric contraction (MVIC) of the knee extensor muscles, countermovement jump (CMJ) performance and muscle soreness ratings (DOMS) at 24-, 48- and 72-hrs post-exercise.ResultsSpO2 (HYP: 76.7 ± 3.8%, CON: 95.5 ± 1.7%, p < 0.001) and SmO2 (HYP: 60.0 ± 9.3, CON: 73.4 ± 5.8%, p = 0.03) values were lower (p < 0.05) in HYP compared to CON at the end of the exercise-protocol. No physiological differences between HYP and CON were observed for HR, Tcore, and Tskin (all p > 0.05). There were also no differences detected for any recovery variable (CK, CRP, BSR, MVIC, CMJ, and DOMS) during the 72-hrs follow-up period between HYP and CON (all p > 0.05).ConclusionIn conclusion, our results showed that muscle damaging exercise under HYP leads to reduced capillary and muscle oxygenation levels compared to normoxia with no difference in inflammatory response and muscle recovery during 72 h post-exercise.Trial registrationNCT04902924, May 26th 2021.

Acute and chronic musculoskeletal pain situations among the working population and their pain education needs: an exploratory study.

Pain affects a person's physical and psychological well-being, work performance and productivity. Working population bear their pain and continue to work which may contribute to the worsening of their pain condition. However, their pain situation was not well-examined. The aim of the study was to explore the prevalence of acute and chronic pain in the working population in Hong Kong, understand their pain management strategies and determine their preferences with regard to the use of electronic pain management materials. This was an exploratory online survey. The participants' pain history, their preferences in methods of pain management, the source of the pain management education that they had received, sources and preferences in relation to the use of the Internet for pain education, and the participants' demographic characteristics were collected. A total of 210 participants joined the study, 67% of whom were experiencing pain. Of the group in pain, 71.6% were in chronic pain that has persisted for 3 months or more. Pain intensities ranged from 2.82 to 3.82 on a 10-point numeric scale. Of the participants, 85.7% reported not receiving adequate pain management education, and 91.4% of those agreed pain services were inadequate. Websites and health care professionals were the sources from which they obtained their pain management education. The high prevalence of pain in the working population requires special attention. Health care professionals should be proactive and an online pain management programme can be a solution to address the critical problem of pain in the working population.

Digital Pain Drawings Can Improve Doctors' Understanding of Acute Pain Patients: Survey and Pain Drawing Analysis.

BackgroundPain drawings (PDs) are an important tool to evaluate, communicate, and objectify pain. In the past few years, there has been a shift toward tablet-based acquisition of PDs, and several studies have been conducted to test the usefulness, reliability, and repeatability of electronic PDs. However, to our knowledge, no study has investigated the potential role of electronic PDs in the clinical assessment and treatment of inpatients in acute pain situations.ObjectiveThe aim of this study was to evaluate whether knowledge of the patients’ electronic PD has the potential to improve the doctors’ understanding of their patients and to influence their clinical decision making. Furthermore, we sought to identify differences between electronic PDs of patients and their treating pain specialists in an acute pain situation and to find those specific characteristics derived from the PDs that had the largest impact on doctors’ understanding.MethodsWe obtained electronic PDs from 47 inpatients in acute pain situations before their consultation with a pain specialist on a tablet personal computer with a stylus. Before looking at their patients’ drawings, these specialists drew their own conception of the patients’ pain after anamnesis and physical examination. Patients’ drawings were then revealed to the doctors, and they were asked to evaluate how much the additional information improved their understanding of the case and how much it influenced their clinical decision on an 11-point Likert scale (0=“not at all” and 10=“very much”). Similarities and differences of patients’ and doctors’ PDs were assessed by visual inspection and by calculating Jaccard index and intraclass correlation coefficient (ICC) of the pain area and the number of pain clusters. Exploratory analyses were conducted by means of correlation tables to identify specific factors that influenced doctors’ understanding.ResultsPatients’ PDs significantly improved the doctors’ understanding (mean score 4.81, SD 2.60, P<.001) and to a lesser extent their clinical decision (mean 2.68, SD 1.18, P<.001). Electronic PDs of patients and doctors showed fair to good similarity for pain extent (r=.454, P=.001) and widespreadness (P=.447, r=.002) were important factors helping doctors to understand their patients.ConclusionsIn a clinical setting, electronic PDs can improve doctors’ understanding of patients in acute pain situations. The ability of electronic PDs to visualize differences between doctors’ and patients’ conception of pain has the potential to improve doctor-patient communication.

Oral health and the care of pregnant women: workshops as a strategy to problematize practices in basic health care in residents living in the peripheral areas of the hills in the city of Santos

ABSTRACT Objective: the aim of this study is to question Primary Health Care (PHC) concerning oral health during prenatal care in facilities of primary health care in the residents living in the hills peripheral areas of the city of Santos, São Paulo. Methods: Using a qualitative approach, workshops on PHC concerning oral health were held in three primary care units which present different forms of organization. The transcribed material was analyzed using thematic analysis. Results: the teams have been trying to organize dental agendas giving priority to pregnant women, however difficulties in monitoring attendance commitment have been found. Therefore the use of protocols and the approach to oral health theme during the educational groups have been used as strategies for improving treatment commitment. Regardless of the organization of the PHC unit, the teams have claimed the search for pregnant women care merely in acute painful situations as well as the fear of harming the fetus caused by dental treatment as the main cause of treatment dropout. Some professionals had doubts about the use of local anesthetics in pregnant women. Conclusions: The valorization of oral health care during prenatal care was not unanimous among the professionals and the use of the permanent education strategy applied in the services led the teams to carefully question their practice as well as search for practice integrality.

Non-Invasive Nasal Hydromorphone with High Bioavailability for Rapid Onset and Non-Dissociative Acute Pain Control: A Feasibility Study

Aim: To test the hypothesis that intranasal hydromorphone could mimic IV administration parameters for use in acute pain situations such as battle field injury, EMS first response and breakthrough cancer pain. Methods: A single healthy volunteer was recruited to a monocentric, open label, randomized, four-way crossover pharmacokinetic study, with 7 days washout period between treatments (more than 70 times the terminal elimination half-life). The use of a single subject minimized the effect of person to person variability in metabolism. For small molecule drugs (i.e., MW<1,000 Daltons) nasal bioavailability in the presence of alkylsaccharide absorption enhancers is predominantly a function of molecular weight and is expected to be high. Unexpected impediments to nasal delivery are likely due to local mucosal irritation or vasoconstriction, which can reduce bioavailability. According to an analysis of FDA data by eHealthMe, of 18,420 people reported to have side effects when taking hydromorphone, only 1 person reported vasoconstriction. The subject received 2 mg oral hydromorphone vs. 3 different formulations of 2 mg intranasal hydromorphone administered using a 100 μl Aptar multidose spray pump (Aptar Group, Crystal Lake, IL). Hydromorphone concentrations were evaluated by HPLC-MS/MS. Bioavailability was calculated using trapezoidal methodology to determine area under the curve. Results and conclusion: Moderate euphoria was observed for all dosage forms, nasal and oral. Oral concentrations were fairly low at all reportable time periods, with Tmax at minute 60 and Cmax 1.5 ng/mL. All intranasal formulations exhibited a greatly improved Tmax of 10 minutes and improved Cmax values. IN-3 had a significantly better Cmax value of 6.6 ng/ml respectively and drug effect was noted as early as minute 1, experienced as a moderate euphoria which lasted until minute 120, then tapering off. We believe the proprietary formulations of intranasal hydromorphone should be further investigated and developed.

Catestatin, vasostatin, cortisol, temperature, heart rate, respiratory rate, scores of the short form of the Glasgow composite measure pain scale and visual analog scale for stress and pain behavior in dogs before and after ovariohysterectomy.

BackgroundThe stress reaction induced by surgery and associated pain may be detrimental for patient recovery and should be minimized. The neuropeptide chromogranin A (CGA) has shown promise as a sensitive biomarker for stress in humans. Little is known about CGA and its derived peptides, catestatin (CST) and vasostatin (VS), in dogs undergoing surgery. The objectives of this study were to investigate and compare concentrations of CGA epitopes CST and VS, cortisol, body temperature, heart rate, respiratory rate, scores of the short form of the Glasgow composite measure pain scale (CMPS-SF) and visual analog scales (VAS) for stress and pain behavior in dogs before and after ovariohysterectomy.MethodsThirty healthy privately owned female dogs admitted for elective ovariohysterectomy were included. Physical examination, CMPS-SF, pain behavior VAS, and stress behavior VAS were recorded and saliva and blood samples were collected before surgery, 3 h after extubation, and once at recall 7–15 days after surgery. Dogs were premedicated with morphine and received carprofen as analgesia for 7 days during the postoperative period.ResultsAt 3 h after extubation, CMPS-SF and pain behavior VAS scores had increased (p < 0.0001) and stress behavior VAS scores, temperature, respiratory rate (p < 0.0001), plasma CST concentrations (p = 0.002) had decreased significantly compared to before surgery. No significant differences were observed in the subjective and physiological parameters between before surgery and at recall, but plasma CST (p = 0.04) and serum cortisol (p = 0.009) were significantly lower at recall. Plasma VS, saliva CST, and heart rate did not differ significantly at any observed time.ConclusionStudy parameters for evaluating surgery-induced stress and pain changed in dogs subjected to ovariohysterectomy. To further evaluate CST and VS usefulness as pain biomarkers, studies on dogs in acute painful situations are warranted.

Survey of young patients with polio and a foreign background at a Swedish post-polio outpatient clinic.

Nowadays, polio survivors aged under 60years are non-native Swedes which pose new aspects and challenges to a post-polio outpatient clinic. To analyze the medical data, walking aids, occupational, and family situation in non-native polio survivors aged less than 60years at a Swedish post-polio outpatient clinic. Retrospective data analysis. Data were retrieved from medical records at the post-polio outpatient clinic. Actual age, age at acute polio infection, walking capacity, pain, concomitant diseases, working and family situation, and ethnical origin were analyzed. Data are presented in numbers and percentage. 153 patients were included. Mean age was 45 (17-60) years, and mean age at acute polio infection was 2 (0-12) years. Paresis of the lower extremities was the most common disability. 10% were wheelchair dependent. Pain occurred in 70% with a mean intensity of 55 measured with the visual analog scale. Hypertension was the most common concomitant disease. Half of the polio survivors were working at least part time, and roughly half were singles. Data were comparable with data earlier published in Swedish native polio survivors. Non-native polio survivors aged under 60years showed similarities in age at acute polio infection, paresis, prevalence, and intensity of pain when compared with native Swedish polio survivors. They were, however, younger, and were less often working and married/cohabitants than native Swedish polio survivors. The results of this study underline the importance of social and vocational rehabilitation tailoring rehabilitation suitable for polio survivors with a foreign background.

(512) The impact of virtual reality on chronic pain

There is an urgent need for non-opioid alternatives in the treatment of chronic pain. To date, studies have convincingly shown that the powerful distraction effect of virtual reality (VR) makes it an effective tool for use with acute pain situations such as on burn units and for painful procedures. However, to date there have been no studies on the use of VR for chronic pain conditions. Almost all VR studies to date have used “Snow World” as the software program. This program was developed at the University of Washington. However, just this year a new company – DeepStream VR - has been formed by some of the engineers who developed “Snow World.” Their new product “Cool” is the one being tested at our clinic. With advent of Oculus Rift the hardware is now also available for use outside of the University of Washington setting. The studies at our clinic are, to our knowledge, the first in the country to study VR for use with chronic pain. This poster will review the data we will have from our two clinical trials on VR and “Cool.” One trial of 50 patients is studying the effect on a five minute VR session on pain scores for patients with chronic pain. We expect to see a decrease in pain scores pre-post the VR session. This is a simple proof of concept study to determine if VR, which has been shown to be effective with acute pain, is also effective in reducing chronic pain. The second study involves a randomized trial of 20 subjects with a neuropathic pain diagnosis. We will offer three 20-minute VR sessions and assess change in and duration of impact on pain scores. We will also assess the impact of the three VR sessions on depression, anxiety, self-efficacy and catastrophizing.

Enjeux et difficultés de la relation entre soignants et patients drépanocytaires au cours de la crise douloureuse aiguë

Sickle cell patients in acute pain situation experiment cognitive, behavioral and emotional changes that can accentuate their pain and disrupt communication with caregivers. On the other hand, caregivers have to face pain assessment difficulties and their own psychological reactions to their patient's pain. The gap between the patient's experience and caregiver's evaluation can lead to conflict and non-adherence treatment, and have a direct impact on the sickle cell disease prognosis. There is nothing inevitable about these phenomena, whose knowledge allows the action and opens up prospects for improving the management of sickle cell disease pain. This article is a narrative review updating the interactions between acute pain and some configurations, such as the inability to discern emotions, catastrophizing, post-traumatic stress or feeling ostracized. The overestimation of patient's addiction by caregivers also influences the pain itself. Open communication, as well as some treatments, medicated or not, a consistent institutional organization and a multidisciplinary approach altogether have an analgesic role by acting on pain cognitive and emotional components.

Efficacy and Speed of Onset of Pain Relief of Fast-Dissolving Paracetamol on Postsurgical Dental Pain: Two Randomized, Single-Dose, Double-Blind, Placebo-Controlled Clinical Studies

BackgroundParacetamol (APAP), also known as acetaminophen, is the most commonly used over-the-counter analgesic for the treatment of mild-to-moderate pain. However, the speed of onset of pain relief is limited mainly to the standard, immediate-release formulation. Efficacy and speed of onset of pain relief are critical in acute pain situations such as postsurgical dental pain, because reducing pain can improve clinical outcome and reduce the risk of transition from acute pain to more chronic pain. Efficacy and rapid onset also reduce the risk of excessive dosing with the analgesic. ObjectiveWe sought to investigate the dose–response efficacy and speed of onset of pain relief of a fast-dissolving APAP formulation compared with lower doses of APAP and placebo in dental patients after impacted third molar extraction. MethodsTwo single-center, single-dose, randomized, placebo-controlled, double-blind, double-dummy, parallel-group studies (Study I and Study II) were conducted to evaluate the efficacy and speed of onset of pain relief of different doses of a fast-dissolving APAP tablet (FD-APAP), standard APAP, and placebo in patients with postsurgical dental pain following third molar extraction. In Study I, a single dose of FD-APAP 1000 mg, FD-APAP 500 mg, or placebo was given to 300 patients; in Study II, a single dose of FD-APAP 1000 mg, standard APAP 650 mg, or placebo was given to 401 pateints. All 701 patients from both studies were included in the analysis and safety assessment. ResultsFD-APAP 1000 mg demonstrated significantly greater effect compared with FD-APAP 500 mg, APAP 650 mg, and placebo for all efficacy measurements, including sum of pain relief and pain intensity difference, total pain relief, sum of pain intensity difference, pain intensity difference, and pain relief score during 6 hours after the dose. Onset of confirmed first perceptible relief in subjects treated with FD-APAP 1000 mg was 15 minutes, which was 32% and 25% significantly shorter than onset of pain relief of FD-APAP 500 mg (22 minutes) and standard APAP 650 mg (20 minutes), respectively. FD-APAP 500 mg and APAP 650 mg demonstrated efficacy over placebo for most of the measurements; however, their effects were significantly lower and lasted for a shorter period of time than for FD-APAP 1000 mg. All study treatments were well tolerated. ConclusionsFD-APAP 1000 mg tablets demonstrated efficacy over placebo. Also, FD-APAP 1000 mg had significantly superior effect, faster onset, and longer duration of pain relief compared with FD-APAP 500 mg and APAP 650 mg tablets. ClinicalTrials.gov identifiers: NCT01082081 and NCT01075243.

Single dose oral ibuprofen plus oxycodone for acute postoperative pain in adults

Combining two different analgesics in fixed doses in a single tablet can provide better pain relief than either drug alone in acute pain. This appears to be broadly true across a range of different drug combinations, in postoperative pain and migraine headache. Fixed-dose combinations of ibuprofen and oxycodone are available, and the drugs may be separately used in combination in some acute pain situations. To assess the analgesic efficacy and adverse effects of a single oral dose of ibuprofen plus oxycodone for moderate to severe postoperative pain. We searched the Cochrane Central Register of Controlled Trials, (CENTRAL), on The Cochrane Library, (Issue 4 of 12, 2013), MEDLINE (1950 to 21st May 2013), EMBASE (1974 to 21st May 2013), the Oxford Pain Database, ClinicalTrials.gov, and reference lists of articles. Randomised, double-blind clinical trials of single dose, oral ibuprofen plus oxycodone compared with placebo or the same dose of ibuprofen alone for acute postoperative pain in adults. Two review authors independently considered trials for inclusion in the review, assessed quality, and extracted data. We used the area under the pain relief versus time curve to derive the proportion of participants prescribed ibuprofen plus oxycodone, ibuprofen alone, oxycodone alone, or placebo with at least 50% pain relief over six hours, using validated equations. We calculated relative risk (RR) and number needed to treat to benefit (NNT). We used information on use of rescue medication to calculate the proportion of participants requiring rescue medication and the weighted mean of the median time to use. We also collected information on adverse events. Searches identified three studies involving 1202 participants. All examined the same dose combination. Included studies provided data from 603 participants for the comparison of ibuprofen 400 mg + oxycodone 5 mg with placebo, 717 participants for the comparison of ibuprofen 400 mg + oxycodone 5 mg with ibuprofen 400 mg alone, and 471 participants for the comparison of ibuprofen 400 mg + oxycodone 5 mg with oxycodone 5 mg alone.The proportion of participants achieving at least 50% pain relief over 6 hours was 60% with ibuprofen 400 mg + oxycodone 5 mg and 17% with placebo, giving an NNT of 2.3 (2.0 to 2.8). For ibuprofen 400 mg alone the proportion was 50%, producing no significant difference between ibuprofen 400 mg + oxycodone 5 mg and ibuprofen 400 mg alone. For oxycodone 5 mg alone the proportion was 23%, giving an NNT for ibuprofen 400 mg + oxycodone 5 mg compared with oxycodone alone of 2.9 (2.3 to 4.0).Ibuprofen + oxycodone resulted in longer times to remedication than with placebo. The median time to use of rescue medication was more than 5 hours for ibuprofen 400 mg + oxycodone 5 mg, and 2.3 hours or less with placebo. Fewer participants needed rescue medication with ibuprofen + oxycodone combination than with placebo or ibuprofen alone. The proportion was 40% with ibuprofen 400 mg + oxycodone 5 mg, 83% with placebo, 53% with ibuprofen alone, and 83% with oxycodone alone, giving NNT to prevent one patient needing rescue medication of 2.4 (2.0 to 2.9), 11 (6.1 to 56), and 2.6 (2.1 to 3.4) for comparisons of ibuprofen 400 mg + oxycodone 5 mg with placebo, ibuprofen alone, and oxycodone alone, respectively.The proportion of participants experiencing one or more adverse events was 25% with ibuprofen 400 mg + oxycodone 5 mg, 25% with placebo, 26% with ibuprofen alone, and 35% with oxycodone alone; they were not significantly different. Serious adverse events were reported only after abdominal surgery 6/169 with the combination, 1/175 with ibuprofen alone, 3/52 with oxycodone alone, and 1/60 with placebo. Withdrawals for reasons other than lack of efficacy were fewer than 5% and balanced across treatment arms. The combination of ibuprofen 400mg + oxycodone 5mg provided analgesia for longer than oxycodone alone, but not ibuprofen alone (at the same dose). There was also a smaller chance of needing additional analgesia over about eight hours, and with no greater chance of experiencing an adverse event.

Effect of lesions of A5 or A7 noradrenergic cell group or surgical transection of brainstem catecholamine pathways on plasma catecholamine levels in rats injected subcutaneously by formalin

The pain-induced activation of the sympatho-adrenal system is modulated by several brain areas, including brainstem catecholamine cell groups. In the present study, we evaluated the effect of bilateral lesions of the A5 or A7 cell groups or bilateral transections of brainstem catecholaminergic pathways on plasma catecholamine levels in Sprague-Dawley rats injected subcutaneously by formalin or saline. Plasma levels of both epinephrine and norepinephrine were slightly elevated after formalin injections within 15-30 min in rats with or without lesions of the A7 catecholamine cell group. However, saline but not formalin elicited a significant increase in plasma epinephrine level in both sham-operated and A5-lesioned groups. It is more likely, that formalin blocks the effect of the handling and the painful injection procedure. In rats with bilateral partial transections of the lower brainstem, formalin was more effective than saline in the elevation of plasma epinephrine and norepinephrine levels at several time-points through the investigation period. Our data indicate the involvement of A5 and A7 norepinephrine neurons and brainstem catecholaminergic pathways in the regulation of the activity of the sympatho-adrenal system during acute painful situations. Their modulatory effect, however, seems to be a very rapid one, short and moderate.

Increase in reactive oxygen species and activation of Akt signaling pathway in neuropathic pain.

Neuropathic pain occurs as a result of peripheral or central nervous system injury. Its pathophysiology involves mainly a central sensitization mechanism that may be correlated to many molecules acting in regions involved in pain processing, such as the spinal cord. It has been demonstrated that reactive oxygen species (ROS) and signaling molecules, such as the serine/threonine protein kinase Akt, are involved in neuropathic pain mechanisms. Thus, the aim of this study was to provide evidence of this relationship. Sciatic nerve transection (SNT) was used to induce neuropathic pain in rats. Western blot analysis of Akt and 4-hydroxy-2-nonenal (HNE)-Michael adducts, and measurement of hydrogen peroxide (H(2)O(2)) in the lumbosacral spinal cord were performed. The main findings were found seven days after SNT, when there was an increase in HNE-Michael adducts formation, total and p-Akt expression, and H(2)O(2) concentration. However, one and 15 days after SNT, H(2)O(2) concentration was raised in both sham (animals that were submitted to surgery without nerve injury) and SNT groups, showing the high sensibility of this ROS to nociceptive afferent stimuli, not only to neuropathic pain. p-Akt also increased in sham and SNT groups one day post injury, but at 3 and 7 days the increase occurred exclusively in SNT animals. Thus, there is crosstalk between intracellular signaling pathways and ROS, and these molecules can act as protective agents in acute pain situations or play a role in the development of chronic pain states.

Non-Scandinavian and Scandinavian women's expectations and experiences of acute pain

Summary Background Cultural or ethnic background has been shown to be significant for how individuals experience pain. The aim of this study was to examine the expectation and experience of acute pain, the use of stress-coping styles, and the distribution of analgesics among non-Scandinavian and Scandinavian women in a dental treatment situation. Methods Instruments used were the Visual Analogue Scale (VAS) and the Jalowiec Coping Scale (JCS). Results Non-Scandinavian women rated both expected and experienced pain significantly higher than Scandinavian women. No significant differences were found in stress-coping styles or in the distribution of analgesics between the two groups. Conclusion Nurses in acute pain situations must be aware of the need for appropriate assessment tools as well as the need to be sensitive to variations in both verbal and non-verbal communication styles across cultures.

Erythromycin promotes gastric emptying during acute pain in volunteers

In this double-blind cross-over study, we assessed whether erythromycin infusion is effective as a prokinetic drug against gastroparesis from acute pain. The effect of erythromycin on gastric emptying (GE) was measured in seven volunteers subjected to a standardized acute painful stimulus. The GE rate for solids was measured using the octanoic acid breath test. An acetaminophen absorption test measured the GE rate for liquids. Five minutes after ingestion of a 13C-labeled meal, the subjects received in randomized order either a test (placebo and erythromycin groups) or a control (control group) stimulus consisting of repeated 1-min immersion of a hand into 4 degrees C (test) or 37 degrees C (control) water, with 15 s for recovery between immersions, for a total of 20 min. While the stimulus was applied, 250 mL saline (control and placebo groups) or 250 mg erythromycin (erythromycin group) was infused. Pain and stress were evaluated using visual analog scales, and standard hemodynamic values were recorded throughout the study. Our results show that acute stress decreased GE for solids, which was significantly accelerated in the erythromycin group in comparison with the placebo group. GE for liquids was similar in the three groups. We conclude that erythromycin is effective as a prokinetic drug for solids in acute painful situations.

Efficacy and plasma levels of ropivacaine for children: controlled regional analgesia following lower limb surgery

Continuous regional analgesia (CRA) is considered a safe and efficacious technique for postoperative pain relief in children after lower limb surgery. We recently evaluated the feasibility of patient-controlled regional analgesia (PCRA) in a similar acute pain situation and we concluded that PCRA might be advantageous over CRA in terms of lower costs, risk of systemic toxicity while producing similarly adequate analgesia. We therefore prospectively compared both techniques in the paediatric population. In total, 30 children undergoing lower limb orthopaedic surgery were randomized to receive PCRA or CRA with ropivacaine 0.2%. Visual analogue scale scores, rescue analgesia, overall satisfaction, motor blockade and plasma ropivacaine concentrations were recorded for 48 h. Adequate analgesia was achieved with both techniques. No significant difference was noted for rescue analgesia, overall satisfaction and motor blockade. In contrast, children in the PCRA group received significantly less local anaesthetics than those in the CRA group. In addition, total plasma concentrations of ropivacaine were significantly reduced in the PCRA group as compared with the CRA group during the 48 h postoperative period. Both techniques are efficacious and satisfactory. However, PCRA with ropivacaine 0.2% can provide adequate postoperative analgesia for paediatric orthopaedic procedures with smaller doses of ropivacaine than CRA.

Erythromycin Promotes Gastric Emptying During Acute Pain in Volunteers

In this double-blind cross-over study, we assessed whether erythromycin infusion is effective as a prokinetic drug against gastroparesis from acute pain. The effect of erythromycin on gastric emptying (GE) was measured in seven volunteers subjected to a standardized acute painful stimulus. The GE rate for solids was measured using the octanoic acid breath test. An acetaminophen absorption test measured the GE rate for liquids. Five minutes after ingestion of a 13C-labeled meal, the subjects received in randomized order either a test (placebo and erythromycin groups) or a control (control group) stimulus consisting of repeated 1-min immersion of a hand into 4 degrees C (test) or 37 degrees C (control) water, with 15 s for recovery between immersions, for a total of 20 min. While the stimulus was applied, 250 mL saline (control and placebo groups) or 250 mg erythromycin (erythromycin group) was infused. Pain and stress were evaluated using visual analog scales, and standard hemodynamic values were recorded throughout the study. Our results show that acute stress decreased GE for solids, which was significantly accelerated in the erythromycin group in comparison with the placebo group. GE for liquids was similar in the three groups. We conclude that erythromycin is effective as a prokinetic drug for solids in acute painful situations.

Opioids in anesthesia

Opioids are by far the oldest known analgesics, and their versatility in the practice of anesthesia and pain management remains unchallenged. It behooves any physician dealing with acute pain situations to have a working knowledge of the mechanisms through which opioids produce analgesia and the locations in the body where opioids work. Knowledge of the physical properties of the various opioids can help the practitioner predict how a given opioid will function when administered by a particular route, eg, epidural versus intravenous. In this article, the actions and properties of opioids will be reviewed with emphasis placed on their use in clinical practice.

Does unspecific low back pain really exist?

Only 20 % of low back pain or sciatica is of a specific origin. These specific pain conditions include tumours, spondylitis, rheumatic and metabolic diseases as well as radicular syndromes. By far the most pain from discs, facet and sacroiliac joints, ligaments and muscles must be considered as unspecific, because no anamnestic information or clinical signs exist (radiological changes included) to assign pain to structural or functional correlates. In addition, the therapeutic consequences from the assignment of structural changes to pain remain unclear. In acute pain situations the specificity of the pain is not important because of the fast relief of the disease, in chronic pain situations, fear avoidance beliefs and pain behaviour seem to be much more important than structural and functional changes.

Pharmacology of systemic analgesics

Systemic administration of analgesic drugs is still the most widely used method for providing pain relief in acute painful situations. Opioids may be selected on the basis of their physicochemical characteristics and their diffusion index to the brain. But in clinical practice, their very steep concentration–analgesic effect relationship remains a critical aspect of opioid therapy. Thus, small fluctuations in plasma concentrations of opioids may lead to profound fluctuations in analgesic effect when their plasma and effect-site concentrations are near the minimum effective analgesic concentration (MEAC). Combining drugs acting on different mechanisms of nociceptive modulation offers benefits from additive/synergistic effects and will decrease the incidence of their adverse effects. Evidence-based reviews showed that effective pain relief using non-opioid analgesics relied on paracetamol supplemented with non-steroidal anti-inflammatory drugs (NSAIDs). The role of COX-2 selective inhibitors (CSIs) in acute pain relief still requires further evaluation. NSAIDs, CSIs and paracetamol share the property of morphine sparing in situations of severe (post-operative) pain. CSIs may be beneficial in patients in whom post-operative bleeding is a major surgical risk as the effects of NSAIDs on coagulation may last for days. Finally, low-dose ketamine infusions remain a worthwhile addition to opioid therapy. Analgesic concentrations of ketamine are 1/5th to 1/10th the anaesthetic concentration and exert significant inhibition on N–methyl–d-aspartate (NMDA) receptor activation.