Objectively measured activity is not associated with average pain intensity 1 week after surgery: A cross-sectional study

BACKGROUND

Measures of physical activity and pain-related patient-reported outcomes are important components of patient recovery after surgery. However, little is known about their association in the early post-operative period. This study aims to increase this knowledge. Our primary objective was to determine the association between average pain intensity and activity (in steps) 1 week after surgery. Secondary objectives were the association of activity with other patient-reported outcomes, age, sex, comorbidities and body mass index.

METHODS

Data were obtained from the PROMPT sub-project of IMI-PainCare. Patients after breast and endometriosis-related surgery, sternotomy and total knee arthroplasty completed pain-related outcomes questionnaires and wore an ActiGraph activity-tracking device. We correlated steps with average pain intensity on post-operative days 6 and 7. Secondary analyses were done using correlations and t-tests.

RESULTS

In 284 cases, there was no statistically significant correlation between steps and average pain intensity. In addition, none of the 28 secondary analyses showed a statistically significant result.

CONCLUSIONS

Pain-related patient-reported outcome measures and physical activity are separate entities. Both should be measured after surgery to assess patient recovery and to identify treatment deficiencies.

SIGNIFICANCE STATEMENT

Measuring recovery is a multi-dimensional challenge. After surgery, clinicians need to be aware that neither pain intensity nor activity levels tell the whole story. Each can hint to problems and treatment requirements.

[The guidelines of the Federal Joint Committee on acute pain management : Background and consequences for the practice in hospitals]

The quality of postoperative pain therapy in Germany shows a heterogeneous treatment practice and large differences in quality between individual institutions, The patient representatives in the Federal Joint Committee (G-BA) have therefore decisively campaigned for many years that instruments of non-legislative standards are employed in order to noticeably improve the quality of perioperative pain therapy for patients in Germany. As a result of these efforts, in October 2020 a binding specification for internal quality management was included in the quality management guidelines (QM-RL) by the G‑BA. This describes in concrete terms the structural and procedural requirements for an internal quality management of acute pain for all institutions in which operations and comparable potentially painful interventions are carried out. This article describes the content of this regulation and the resulting consequences for the institutions, the medical and administrative management and especially the role of anesthesia.

Anti-nociceptive effects of oxytocin receptor modulation in healthy volunteers-A randomized, double-blinded, placebo-controlled study

BACKGROUND

There is increasing evidence for oxytocin as a neurotransmitter in spinal nociceptive processes. Hypothalamic oxytocinergic neurons project to the spinal dorsal horn, where they activate GABA-ergic inhibitory interneurons. The present study tested whether the long-acting oxytocin-analogue carbetocin has anti-nociceptive effects in multi-modal experimental pain in humans.

METHODS

Twenty-five male volunteers received carbetocin 100 mcg and placebo (0.9% NaCl) on two different sessions in a randomized, double-blinded, cross-over design. Multi-modal quantitative sensory testing (QST) including a model of capsaicin-induced hyperalgesia and allodynia were performed at baseline and at 10, 60 and 120 min after drug administration. QST data were analysed using mixed linear and logistic regression models. Carbetocin plasma concentrations and oxytocin receptor genotypes were quantified and assessed in an exploratory fashion.

RESULTS

An anti-nociceptive effect of carbetocin was observed on intramuscular electrical temporal summation (estimated difference: 1.26 mA, 95% CI 1.01 to 1.56 mA, p = .04) and single-stimulus electrical pain thresholds (estimated difference: 1.21 mA, 95% CI 1.0 to 1.47 mA, p = .05). Furthermore, the area of capsaicin-induced allodynia was reduced after carbetocin compared to placebo (estimated difference: -6.5 cm² , 95% CI -9.8 to -3.2 cm² , p < .001).

CONCLUSIONS

This study provides evidence of an anti-nociceptive effect of carbetocin on experimental pain in humans.

SIGNIFICANCE

This study provides evidence of the anti-nociceptive effect of intravenous administration of the oxytocin agonist carbetocin in healthy male volunteers.

Management practices for postdural puncture headache in obstetrics: a prospective, international, cohort study

BACKGROUND

Accidental dural puncture is an uncommon complication of epidural analgesia and can cause postdural puncture headache (PDPH). We aimed to describe management practices and outcomes after PDPH treated by epidural blood patch (EBP) or no EBP.

METHODS

Following ethics committee approval, patients who developed PDPH after accidental dural puncture were recruited from participating countries and divided into two groups, those receiving EBP or no EBP. Data registered included patient and procedure characteristics, headache symptoms and intensity, management practices, and complications. Follow-up was at 3 months.

RESULTS

A total of 1001 patients from 24 countries were included, of which 647 (64.6%) received an EBP and 354 (35.4%) did not receive an EBP (no-EBP). Higher initial headache intensity was associated with greater use of EBP, odds ratio 1.29 (95% confidence interval 1.19-1.41) per pain intensity unit increase. Headache intensity declined sharply at 4 h after EBP and 127 (19.3%) patients received a second EBP. On average, no or mild headache (numeric rating score≤3) was observed 7 days after diagnosis. Intracranial bleeding was diagnosed in three patients (0.46%), and backache, headache, and analgesic use were more common at 3 months in the EBP group.

CONCLUSIONS

Management practices vary between countries, but EBP was more often used in patients with greater initial headache intensity. EBP reduced headache intensity quickly, but about 20% of patients needed a second EBP. After 7 days, most patients had no or mild headache. Backache, headache, and analgesic use were more common at 3 months in patients receiving an EBP.

[Staff and organizational requirements for pain services in hospitals : A recommendation from the German Society for Anaesthesiology and Intensive Care Medicine]

Although pain services have been established in many hospitals, there is considerable heterogeneity among them with respect to organization of service, staff and qualifications of staff, and treatment approaches.With this recommendation, the German Society for Anesthesiology and Intensive Care Medicine defines requirements for pain services in hospitals with respect to organizational standards and staff qualifications. The therapy offered by pain services supplements the treatment provided by the other departments involved, ensuring the high quality of specialized pain management in all areas of the hospital. Pain services shall oversee treatment with specialized analgesia techniques as well as the involvement of consultants, bringing together in-hospital pain medicine expertise in one service with availability 24 h and 7 days per week via a single contact. The medical head of the pain service shall be a qualified provider of pain medicine as defined by the German Medical Association and as a minimum should also have undergone additional training in basic psychosomatic medicine. Further members of the medical staff should possess the credentials of a medical specialist: non-medical staff should have completed continuing education in the treatment of pain. Minimal guidelines for personnel resources were defined: these included a specific time frame for first contacts (20 min) and follow-up (10 min) for specific analgesic techniques and for the involvement of consultants (first contact 45 min, follow-up 20 min), with additional time for travel, set-up, training and quality management. In addition to definition of the space and equipment needed, each service should draft its own budget, and this should be adequate and plannable. Written agreements between the disciplines and transparent documentation, including patient-reported outcomes, are recommended to ensure quality. The provision of specialized pain therapy should have high priority over all disciplines or departments.

Staff and organizational requirements for pain services in hospitals : A recommendation from the German Society for Anaesthesiology and Intensive Care Medicine

Although pain services have been established in many hospitals, there is considerable heterogeneity among them with respect to organization of service, staff and qualifications of staff, and treatment approaches.With this recommendation, the German Society for Anesthesiology and Intensive Care Medicine defines requirements for pain services in hospitals with respect to organizational standards and staff qualifications. The therapy offered by pain services supplements the treatment provided by the other departments involved, ensuring the high quality of specialized pain management in all areas of the hospital. Pain services shall oversee treatment with specialized analgesia techniques as well as the involvement of consultants, bringing together in-hospital pain medicine expertise in one service with availability 24 h and 7 days per week via a single contact. The medical head of the pain service shall be a qualified provider of pain medicine as defined by the German Medical Association and as a minimum should also have undergone additional training in basic psychosomatic medicine. Further members of the medical staff should possess the credentials of a medical specialist: non-medical staff should have completed continuing education in the treatment of pain. Minimal guidelines for personnel resources were defined: these included a specific time frame for first contacts (20 min) and follow-up (10 min) for specific analgesic techniques and for the involvement of consultants (first contact 45 min, follow-up 20 min), with additional time for travel, set-up, training and quality management. In addition to definition of the space and equipment needed, each service should draft its own budget, and this should be adequate and plannable. Written agreements between the disciplines and transparent documentation, including patient-reported outcomes, are recommended to ensure quality. The provision of specialized pain therapy should have high priority over all disciplines or departments.

The Quality of Postoperative Pain Therapy in German Hospitals

BACKGROUND

Many patients in German hospitals complain of inadequate treatment of their postoperative pain. Hospital-related structural and procedural variables may affect pain perception and patient satisfaction. We studied the association of individual variables with outcome quality.

METHODS

Data from the years 2011 to 2014 from the world's largest acute pain registry (QUIPS) were evaluated. The analysis was performed with mixed linear regression models.

RESULTS

We studied registry data from 138 German hospitals concerning four commonly performed types of operations (total number of operations, 21 114) and found that the intensity of pain, functional impairment, and satisfaction with postoperative pain therapy were all highly variable from one hospital to another. Patients in university hospitals complained more often than those in standard care facilities of highly intense pain (odds ratio [OR] 2.44; 95% con - fidence interval [CI] [1.18; 5.04]) and dissatisfaction (OR 3.58 [1.85; 6.93]). In specialized centers as well, pain intensity (OR 1.39 [1.06; 1.83]) and dissatisfaction (OR 1.59 [1.25; 2.02]) were higher. Pain-related limitation of movement was also reported more commonly in university hospitals (OR 2.12 [0.87; 5.16]) and specialized centers (OR 1.87 [1.33; 2.65]) than in standard care facilities. Less pain-related limitation of movement and higher satisfaction were reported in hospitals in which pain was documented in the patients' charts and the patients felt adequately informed about the treatment options.

CONCLUSION

The current state of postoperative pain therapy leaves much room for improvement. Quality indicators in the field of acute pain medicine might help improve patient care.

[Organisation of Perioperative Pain Management]

Organisational issues of acute pain management are as important as details of pharmacologic treatments or regional analgesia. Lothar Lachgas is a young intern in the department of anaesthesiology of a German hospital. This overview illuminates organisation of perioperative pain management based on his virtual experiences and questions: pain assessment and documentation, patient information and education, tasks of an Acute Pain Service.

Effect of single-dose imipramine on chronic low-back and experimental pain. A randomized controlled trial

Antidepressants are frequently prescribed as co-analgesics in chronic pain. While their efficacy is well documented for neuropathic pain, the evidence is less clear in musculoskeletal pain conditions. The present study therefore evaluated the effect of the tricyclic antidepressant imipramine on chronic low-back pain in a randomized, double-blinded placebo-controlled design. To explore the mechanisms of action and the influence of drug metabolism, multimodal quantitative sensory tests (QST) and genotyping for cytochrome P450 2D6 (CYP2D6) were additionally performed. A single oral dose of imipramine 75 mg was compared to active placebo (tolterodine 1 mg) in 50 patients (32 females) with chronic non-specific low-back pain. Intensity of low-back pain was assessed on a 0–10 numeric rating scale at baseline and every 30 minutes after drug intake. Multimodal QST were performed at baseline and in hourly intervals for 2 hours. Pharmacogenetic influences of cytochrome P450 were addressed by CYP2D6 genotyping. No significant analgesic effect was detected neither on low-back pain nor on any of the sensory tests in the overall analyses. However, evidence for an interaction of the imipramine effect and CYP2D6 genotype was found for electrical and for pressure pain detection thresholds. Intermediate but not extensive metabolizers had a 1.20 times greater electrical pain threshold (95%-CI 1.10 to 1.31) and a 1.10 times greater pressure pain threshold (95%-CI 1.01 to 1.21) 60 minutes after imipramine than after placebo (p<0.001 and p = 0.034, respectively). The present study failed to demonstrate an immediate analgesic effect of imipramine on low-back pain. Anti-nociceptive effects as assessed by quantitative sensory tests may depend on CYP2D6 genotype, indicating that metabolizer status should be accounted for when future studies with tricyclic antidepressants are undertaken.

Predicting drug efficacy in chronic low back pain by quantitative sensory tests

BACKGROUND

Drugs are prescribed for chronic low back pain without knowing in advance whether a patient will respond to them or not. Quantitative sensory tests (QST) can discriminate patients according to sensory phenotype, possibly reflecting underlying mechanisms of pain processing. QST may therefore be a screening tool to identify potential responders to a certain drug. The aim of this study was to investigate whether QST can predict analgesic effects of oxycodone, imipramine and clobazam in chronic low back pain.

METHODS

Oxycodone 15 mg (n = 50), imipramine 75 mg (n = 50) and clobazam 20 mg (n = 49) were compared to active placebo tolterodine 1 mg in a randomized, double-blinded, crossover fashion. Electrical, pressure and thermal QST were performed at baseline and after 1 and 2 h. Pain intensity was assessed on a 0-10 numeric rating scale every 30 min for up to 2 h. The ability of baseline QST to predict pain reduction after 2 h was analysed using linear mixed models. Genetic variants of drug-metabolizing enzymes and genes affecting pain sensitivity were examined as covariables.

RESULTS

No predictor of analgesic effect was found for oxycodone and clobazam. Thermal QST was associated with analgesic effect of imipramine: patients more sensitive to heat or cold were more likely to experience an effect of imipramine. Pharmacogenetic variants and pain-related candidate genes were not associated with drug efficacy.

CONCLUSIONS

Thermal QST have the potential to predict imipramine effect in chronic low back pain. Oxycodone and clobazam effects could not be predicted by any of the selected QST or genetic variants.

SIGNIFICANCE

Predicting drug efficacy in chronic low back pain remains difficult. There is some evidence that patients more sensitive to heat and cold pain respond better to imipramine.

[Role of anesthesiology in pain medicine and palliative care treatment in German hospitals : Survey of department heads of anesthesiology on treatment structures]

BACKGROUND

The aim of this analysis was to describe the role of anesthesiology departments in pain medicine and palliative care services in German hospitals.

METHOD

In the year 2012, all heads of departments of anesthesiology registered with the German Society of Anesthesiology and Intensive Care Medicine were surveyed about structures of pain medicine and palliative care services in their hospitals using a standardized postal questionnaire.

RESULTS

Out of 408 returned questionnaires (response rate 47%) 403 could be evaluated. Of the hospitals 58% had a designated pain medicine service, in 36 (9%) of the hospitals this was organized as an independent department and in 195 (57%) as part of another department, mostly the department of anesthesiology. The "pain clinic" as an outpatient service was the most common form of structure for pain medicine services (41%). Inpatient pain medicine units were available in 77 (19%) of the hospitals and a partial inpatient unit in the form of a day hospital in 26 (7%) of the hospitals. For the care of inpatients from other departments, there was an intrahospital pain consultation service in 166 of the hospitals, which was the only structure for pain medicine in 32 of the 231 hospitals that reported having a designated pain medicine service. In 160 pain medicine services anesthesiologists were the only medical practitioners and in a further 18 both anesthesiologists and other specialists were available (orthopedist/orthopedic surgeons n = 6, internal medicine n = 4, psychiatrist n = 2, general practitioner = 1 and neurologist n = 1). Only two hospitals had no anesthesiologist in the pain medicine team and for the remaining 51 hospitals no information was provided. In 189 of the 231 hospitals with pain medicine services, there was at least 1 physician with special qualifications in pain management. In 97 (44%) of the hospitals psychologists were part of the team with 53 having at least 1 psychologist with a special qualification in chronic pain management. Of the hospitals, 16% had a specialized department for palliative care, in 32% a specialized palliative care service was part of another department, which was the department of anesthesiology in 30%. Of the hospitals 56% had a palliative care consultation service, 41% had a specialized inpatient palliative care unit, 6% an outpatient clinic, 4% a day hospital and in 16% a specialized outpatient palliative care (SOPC) serving the community was incorporated. Inpatient consultation services and the SOPC were more common when the department of anesthesiology was involved in the palliative care services.

CONCLUSION

In German hospitals, the departments of anesthesiology make a significant contribution to the provision of both pain medicine and palliative care services. Nevertheless, the respective structures of care are often incomplete or even lacking. There were shortcomings in terms of organization and qualification of the team in pain medicine services (e.g. no doctor with special qualifications in pain management or no psychologist). Palliative care services are more often organized as independent departments than as pain medicine services. Engagement of the anesthesiology department in palliative care is linked to a broader scope of the services provided, which might reflect the capacity of many anesthesiologists to work in an interdisciplinary manner and across interfaces.

[Acute pain therapy in German hospitals as competitive factor. Do competition, ownership and case severity influence the practice of acute pain therapy?]

BACKGROUND

Due to the implementation of the diagnosis-related groups (DRG) system, the competitive pressure on German hospitals increased. In this context it has been shown that acute pain management offers economic benefits for hospitals. The aim of this study was to analyze the impact of the competitive situation, the ownership and the economic resources required on structures and processes for acute pain management.

MATERIAL AND METHODS

A standardized questionnaire on structures and processes of acute pain management was mailed to the 885 directors of German departments of anesthesiology listed as members of the German Society of Anesthesiology and Intensive Care Medicine (DGAI, Deutsche Gesellschaft für Anästhesiologie und Intensivmedizin).

RESULTS

For most hospitals a strong regional competition existed; however, this parameter affected neither the implementation of structures nor the recommended treatment processes for pain therapy. In contrast, a clear preference for hospitals in private ownership to use the benchmarking tool QUIPS (quality improvement in postoperative pain therapy) was found. These hospitals also presented information on coping with the management of pain in the corporate clinic mission statement more often and published information about the quality of acute pain management in the quality reports more frequently. No differences were found between hospitals with different forms of ownership in the implementation of acute pain services, quality circles, expert standard pain management and the implementation of recommended processes. Hospitals with a higher case mix index (CMI) had a certified acute pain management more often. The corporate mission statement of these hospitals also contained information on how to cope with pain, presentation of the quality of pain management in the quality report, implementation of quality circles and the implementation of the expert standard pain management more frequently. There were no differences in the frequency of using the benchmarking tool QUIPS or the implementation of recommended treatment processes with respect to the CMI.

CONCLUSION

In this survey no effect of the competitive situation of hospitals on acute pain management could be demonstrated. Private ownership and a higher CMI were more often associated with structures of acute pain management which were publicly accessible in terms of hospital marketing.

[Inpatient acute pain management in German hospitals: results from the national survey "Akutschmerzzensus 2012"]

BACKGROUND

In 2007, the German national guidelines on "Treatment of acute perioperative and post-traumatic pain" were published. The aim of this study was to describe current structure and process data for acute pain management in German hospitals and to compare how the guidelines and other initiatives such as benchmarking or certification changed the healthcare landscape in the last decade.

METHODS

All directors of German departments of anesthesiology according to the DGAI ("Deutschen Gesellschaft für Anästhesiologie und Intensivmedizin", German Society for Anesthesiology and Intensive Care) were mailed a standardized questionnaire on structures and processes of acute pain management in their hospitals.

RESULTS

A total of 403 completed questionnaires (46 %) could be evaluated. Of hospitals, 81 % had an acute pain service (ASD), whereby only 45 % met defined quality criteria. Written standards for acute pain management were available in 97 % of the hospitals on surgical wards and 51 % on nonsurgical wards. In 96 %, perioperative pain was regularly recorded (generally pain at rest and/or movement, pain-related functional impairment in 16 % only). Beside these routine measurements, only 38 % of hospitals monitored pain for effectiveness after acute medications. Often interdisciplinary working groups and/or pain managers are established for hospital-wide control. As specific therapy, the patient-controlled analgesia and epidural analgesia are largely prevalent (> 90 % of all hospitals). In the last decade, intravenous and oral opioid administration of opioids (including slow release preparations) has become established in acute pain management.

CONCLUSION

The survey was representative by evaluating 20 % of all German hospitals. The organizational requirements for appropriate pain management recommended by the German guidelines for acute pain recommended have been established in the hospital sector in recent years. However, the organizational enforcement for acute pain management in nonsurgical areas is not adequate yet, compared to the perioperative care. In all hospitals modern medication and invasive techniques are widely available.

Tramadol and o-desmethyl tramadol clearance maturation and disposition in humans: a pooled pharmacokinetic study

BACKGROUND AND OBJECTIVES

We aimed to study the impact of size, maturation and cytochrome P450 2D6 (CYP2D6) genotype activity score as predictors of intravenous tramadol disposition.

METHODS

Tramadol and O-desmethyl tramadol (M1) observations in 295 human subjects (postmenstrual age 25 weeks to 84.8 years, weight 0.5-186 kg) were pooled. A population pharmacokinetic analysis was performed using a two-compartment model for tramadol and two additional M1 compartments. Covariate analysis included weight, age, sex, disease characteristics (healthy subject or patient) and CYP2D6 genotype activity. A sigmoid maturation model was used to describe age-related changes in tramadol clearance (CLPO), M1 formation clearance (CLPM) and M1 elimination clearance (CLMO). A phenotype-based mixture model was used to identify CLPM polymorphism.

RESULTS

Differences in clearances were largely accounted for by maturation and size. The time to reach 50 % of adult clearance (TM50) values was used to describe maturation. CLPM (TM50 39.8 weeks) and CLPO (TM50 39.1 weeks) displayed fast maturation, while CLMO matured slower, similar to glomerular filtration rate (TM50 47 weeks). The phenotype-based mixture model identified a slow and a faster metabolizer group. Slow metabolizers comprised 9.8 % of subjects with 19.4 % of faster metabolizer CLPM. Low CYP2D6 genotype activity was associated with lower (25 %) than faster metabolizer CLPM, but only 32 % of those with low genotype activity were in the slow metabolizer group.

CONCLUSIONS

Maturation and size are key predictors of variability. A two-group polymorphism was identified based on phenotypic M1 formation clearance. Maturation of tramadol elimination occurs early (50 % of adult value at term gestation).

[Anaesthesia and breast-feeding: should breast-feeding be discouraged?]

Until a few years ago an interruption of breast-feeding for 12 or even 24 hours was recommended for breast-feeding mothers after anaesthesia, this is no longer valid. If it is the mother's wish, if she is sufficiently awake and physically able, there is no reason not to start breast-feeding a mature and healthy baby immediately after recovery from a general or regional anaesthesia. Even breast-feeding after a Caesarean delivery with administration of the common anaesthetics in the usual (single) doses is no longer considered to be a problem since the amount of the substance taken up from colostrum is vanishingly small in comparison to the amount that is transferred by transplacental routes. Neither the pharmacological properties of the drugs used in association with anaesthesia nor clinical experience justify an interruption of breast-feeding.

[Postoperative pain after ambulatory surgery]

BACKGROUND

Outpatient surgeons were surveyed about the quality of postoperative pain therapy after outpatient interventions.

PATIENTS AND METHODS

Of 2,317 outpatient surgeons who received a questionnaire by mail, 419 responded. The return rate was 18.1%. The questionnaire collected data on the operative procedures and methods of anesthesia from 2004 and the analgesics, which were applied in the immediate postoperative period and at home. Methods and contents of quality control were registered.

RESULTS

The respondents indicated that the person responsible for the pain therapy was the surgeon in 74% of the practices, the anesthesiologist in 16%, and both in 10%. The drugs used in the practice were: novaminsulfone (34%), NSAIDs (28%), and opioids (36%). The drugs used for at-home care were: NSAIDs (58%), opioids (43%), novaminsulfone (32%), and mixed analgesics (28%). No analgesics were given by 6%, and 21% prescribed a supplementary antiemetic. Routine pain measurement was performed with pain scales in only 11% of the practices; among the certified practices, 48% performed pain measurement for quality control. Ninety-five percent of the surgeons were satisfied with the pain therapy.

CONCLUSION

This survey shows that the guidelines for acute pain therapy (http://www.awmf.de ) are only partially implemented.

Determination of Opioid Analgesics in Hair Samples Using Liquid Chromatography/Tandem Mass Spectrometry and Application to Patients Under Palliative Care

Hair testing procedures allow a cumulative reflection of long-term drug abuse and are useful as a test for compliance in clinical toxicology. In the present study, liquid chromatography coupled with tandem mass spectrometry was used to determine analgesic opioid drugs in hair samples. The procedure used a simple methanolic extraction, and the evaporated extract was analyzed directly. A selective and sensitive procedure for the simultaneous determination of bisnortilidine, nortilidine, tilidine, buprenorphine, codeine, oxycodone, fentanyl, norfentanyl, hydromorphone, morphine, normorphine, oxymorphone, methadone, piritramide, and tramadol was developed and fully validated. The method fulfilled validation criteria and was shown to be sensitive, with limits of detection ranging from 0.008 to 0.017 ng/mg hair matrix, and precision ranging between 3.1% and 14.9 %. The applicability of the method was shown by analysis of authentic hair samples from patients receiving opioids for the treatment of cancer pain (eg, fentanyl was detected in concentrations up to 0.292 ng/mg, tramadol in concentrations up to 0.612 ng/mg of hair of 1 patient). Hair analysis was shown to be a complementary and useful tool in monitoring the drug-taking behavior of patients consuming opioid analgesics for the treatment of pain. In self-reports and medical records especially, the ingestion of tramadol and methadone was found to be dramatically underreported. In summary, hair analyses gave important additional information for the medical treatment of patients, the results often coming as a surprise to even the attending physicians.

Genomic variations and transcriptional regulation of the human mu-opioid receptor gene

The mu-opioid receptor (MOR1) is a target of endogenous and exogenous opioids and plays a pivotal role for anesthesia and analgesia. Variations in the 5' flanking sequence of the mu-opioid receptor gene may influence transcriptional regulation and ultimately alter protein expression of MOR1. In the present study we investigated the influence of eight single nucleotide polymorphisms (SNP) within the mu-opioid receptor promoter on promoter activity and evaluated the frequencies of the relevant SNPs in 700 patients under opioid medication. Reporter-gene-constructs were created by means of PCR and site directed mutagenesis, testing eight SNPs previously described. The neuroblastoma cell line SHSY5Y was used for transfection and promoter activity was estimated by luciferase activity. Of the eight reporter gene constructs employed to test genomic variations, two produced a significant change in luciferase activity when compared to wild-type constructs. The G-554A variation located within a known NFkB binding element resulted in a decreased activity whereas the A/G base exchange at position -1320 showed an increased luciferase activity. This particular variant generated a myeloid zinc finger (MZF1) cis-acting element known to impact transcription. The allele frequency of the -1320G variant was 0.21% in 700 Caucasian patients under opioid medication in contrast to 9.1% reported previously in drug addicted African Americans. Because of this unexpected low frequency an association analysis to opioid requirements and effects of mu-opioid receptor agonists was not feasible. In conclusion, transcriptional regulation of MOR1 is modified by two genetic variations at positions -554 and -1320 of the mu-opioid receptor promoter. Individuals presenting these variations may have an altered level of MOR expression. A possible association of these genomic variants on efficacy and side effects of opioid treatment in different ethnic groups has to be elucidated.

Genetik, Schmerz und Analgesie

Genomic variations influencing nociceptive sensitivity and susceptibility to pain conditions, as well as responses to pharmacotherapy of pain are currently under investigation. Candidate genes involved in pain perception, pain processing and pain management such as (opioid) receptors, transporters and other targets of pharmacotherapy are discussed. Drug metabolizing enzymes represent a further major target of ongoing research in order to identify associations between an individual's genetic profile and drug response (pharmacogenetics). Polymorphisms of the cytochrome P 450 enzymes influence analgesic efficacy of codeine, tramadol and tricyclic antidepressants (CYP2D6). Blood levels of some non-steroidal anti-inflammatory drugs (NSAIDs) are dependent on CYP2C9 activity, whereas opioid receptor polymorphisms are discussed with respect to differences in opioid-mediated analgesia and side-effects. Pharmacogenetics is seen as a potential diagnostic tool for improving patient therapy and care and will contribute to a more individualized drug treatment in the future.

Effects of tramadol and O-demethyl-tramadol on human 5-HT reuptake carriers and human 5-HT3A receptors: A possible mechanism for tramadol-induced early emesis

([3H]5-HT)-uptake and patch-clamp techniques were used to study the actions of (+) and (-) tramadol and the active metabolites of tramadol, (+) and (-) O-demethyl-tramadol on the human serotonin (5-HT) transporter and the human 5-HT3A receptor, stably expressed in HEK-293 cells. The (+) and (-) enantiomers of tramadol suppressed the human 5-HT transporter concentration-dependently (IC50=1.0 and 0.8 microM, respectively), resulting in 97% and 87% transport inhibition at their respective initial plasma concentrations (9.5 microM). The (+) and (-) enantiomers of the active tramadol metabolite were less potent than tramadol in inhibiting the human 5-HT transporter (IC50=15 and 44 microM, respectively), resulting in 19.2% and 4.8% transport inhibition at their highest plasma concentrations (2.5 microM). In contrast to their potent suppression of the 5-HT transporter, both, (+) and (-) tramadol inhibited 5-HT (30 microM)-induced currents only at substantially higher concentrations (IC50=199 and 251 microM, respectively), resulting in only 6% and 4% inhibition at the initial maximum plasma concentration. A similar low potent inhibition of human 5-HT(3A) receptors was found for (+) and (-) O-demethyl-tramadol (IC50=158 and 63 microM, respectively). In conclusion, at clinical plasma concentrations tramadol potently suppresses the human 5-HT transporter, whereas it has only a slight effect on the human 5-HT3A receptor. The results are compatible with a possible mechanism for tramadol-induced early emesis involving the serotonergic system.

[Does genomics determine efficacy of analgesics?]

Recent advances in knowledge about gene structure derived from the human genome project has also revealed data on genomic variation and their possible impact on complex and acute diseases as well as pharmacotherapy. The hypothesis of a genetic predisposition for complex diseases such as pain syndromes, side effects, and adverse outcomes challenging the clinician is ready to be tested by advanced genetic-epidemiologic study designs employing the latest genotyping technology. In pain therapy, the genetic background of the efficacy of analgesics, especially of opioids, is of particular interest. Genetic differences in drug kinetics and dynamics, e.g., differences in metabolism or genetic variations of the drug target (e.g., receptors) will be of importance in the future. Pharmacogenetics can individualize pharmacotherapy and improve care by predicting the optimal dose and avoiding side effects and toxicity in individual patients.

Prolonged restaurant-associated outbreak of multidrug-resistant Salmonella Typhimurium among patients from several European countries

This report concerns a prolonged restaurant-associated outbreak of infection caused by a multidrug-resistant (ASSuT) strain of Salmonella Typhimurium, phage-type U302, which took place during July and August 2003 and affected people from Denmark and neighbouring countries who had attended a specific restaurant. The outbreak comprised 67 laboratory-verified cases and ten probable cases; however, the actual number of patients was estimated to be more than 390. The outbreak strain was isolated from a buffet which was probably contaminated by an assistant chef who was found to excrete the epidemic strain. An attack rate of 7.3% was estimated and long incubation periods were observed, including one extreme instance of 27 days. This outbreak underscores the importance of conscientious personal hygiene, including frequent washing of hands, for professionals handling food.

[Postoperative pain therapy in Germany]

OBJECTIVE

A survey was performed to obtain information on the organization and practice of postoperative pain management.

METHODS

A questionnaire was mailed to 773 directors of German departments of anesthesiology.

RESULTS

A total of 446 replies (57.7%) could be analyzed. Of the departments, 161 (36.1%) had established an acute pain service (APS), more often in hospitals > or = 1000 beds (63%) than in hospitals with 400-999 beds (40%) and hospitals with < 400 beds (27%). Epidural analgesia was practiced in 97% of the departments, however, it was the analgesic technique of choice for larger abdominal surgery or amputation of the lower limb only in 60.8% and 45.5% of the departments, respectively. Departments with APS provided epidural analgesia more often on general wards than departments without APS (88.2% vs. 68.4%, p < 0.01). Technically more challenging methods (e.g. catheters for regional anesthesia, PCA, PCEA) were more often provided in hospitals running an APS (p < 0.001).

CONCLUSIONS

The number of departments with APS has increased over the last 10 years. Future decisions on reimbursement should consider this extensive service.

[Current practices in obstetrical analgesia in German university clinics. Results of a 1996 survey. Part 2]

Obviously there is a world-wide trend towards regional analgesia for pain relief during delivery. Data on the current practice in Germany are lacking.

METHODS

In 1996 questionnaires on obstetric anaesthesia and analgesia were mailed to all university departments of anaesthesia.

RESULTS

All 38 university hospitals with obstetric units replied (100%). Mean annual delivery rate was 1156. Epidural analgesia (EA) (n = 22), intramuscular injection of opioids (n = 18), and non-opioids as a suppository (n = 17) were often used for pain relief during labour. Intravenous injections (n = 12) or pudendus anaesthesia (n = 7) were practised as well. Entonox (N2O/O2), paracervical blocks or transcutaneous electrical stimulation (TENS) was rarely used. EA for relief of labour pain was offered in all university hospitals. Twelve of them had an epidural rate of less than 10%, in nine the rate was 10-19%, in eight hospitals 20-29% and 30% or more in nine. Indication for EA was a demand by the parturient (n = 34), by the obstetrician (n = 26) or the midwife (n = 18), predominantly because of prolonged labour (n = 32) or significant pain (n = 21). Half of the university departments used an epidural combination of local anaesthetics (bupivacaine) and opioids (sufentanil (n = 12) and/or fentanyl (n = 9)). In all but one department the application of an epidural catheter was performed by anaesthesiologists exclusively. In some hospitals obstetricians (n = 10) or midwives (n = 4) were allowed to give epidural top-up injections. Of the 38 university departments 11 had an anaesthesiologists on duty 24 h a day responsible for the obstetric unit exclusively.

CONCLUSION

In 1977, 14 of 18 university departments of anaesthesiology offered epidural analgesia for parturients. This option was available in all university departments in 1996. A mean rate of 10-20% epidurals for vaginal delivery is well within the limits reported from other countries, whereas the rate of regional anaesthesia for scheduled caesarean section (40%) still is rather low in Germany, as reported in part 1 of this survey (Anaesthesist 1998;47:59-63).

[Current practices in anesthesia for cesarean section in german university clinics. Results of a survey in the year 1996]

Obviously there is a world-wide trend towards regional anaesthesia for caesarean section (CS). Data on the current practice in Germany are lacking.

METHODS

In 1996 questionnaires on obstetric anaesthesia were mailed to all University departments of anaesthesia.

RESULTS

All 38 University Hospitals with obstetric units replied (100%). Mean annual delivery rate was 1156 with a mean CS-rate of 24%. For scheduled CS the University departments used general anaesthesia in most cases (60%), followed by epidural (31%) and spinal anaesthesia (9%). General anaesthesia was predominantly used for more urgent (87%) or emergency deliveries (99%). Spinal anaesthesia was offered to patients as an option of anaesthesia for CS in 16 of 38 departments, epidural anaesthesia in 36 of 38. The majority of university hospitals (22 of 38) performed more than 25% of their CS in epidural anaesthesia; 14 departments had a ratio of at least 50% of regional anaesthesia. 28 of 32 centres administered some kind of acid aspiration chemoprophylaxis as a routine management. Special devices for the management of a difficult airway were provided in 61% of the hospitals within the delivery unit. In 70% the anaesthesiologist was responsible for the postoperative pain management following CS.

CONCLUSION

A significant trend towards regional anaesthesia for CS has taken place in German university hospitals: According to a former survey regional anaesthesia was used in less than 10% of CS in 1977, whereas in the current evaluation from 1996 this figure was significantly higher (40%). Nevertheless, compared to other countries the rate of general anaesthesia still is rather high.

[Forgotten pain]

A 55-year-old female patient developed a severe chronic lumbar pain syndrome over a period of 17 years. An intervertebral disc operation was performed 5 years after the start of the painful illness. The patient later developed resistance to therapy and was unable to stand or walk. She was confined to bed and wheelchair and socially completely withdrawn. Drug therapy and invasive therapeutic techniques escalated. An intrathecal catheter for morphine administration had to be removed owing to bacterial meningitis, and repeated malfunction led to several revisions of an epidural catheter. Withdrawal of the morphine therapy, carried out with the patient's agreement, was complicated by an epileptic seizure and an acute circulatory failure with cerebral hypoxia. The succeeding severe amnestic syndrome extinguished all recollection of the last 20 years, including the entire course of the painful illness. The patient could then be mobilised without pain. Consistent care avoided a relapse into the pain syndrome as the amnestic syndrome gradually receded. The patient was fully able to accept responsibility and not longer required special pain therapy. The course demonstrates that chronic pain disorders of a predominantly psychodynamic, and therefore corticocerebral, genesis are dependent on an intact memory. In such cases memory failure can induce pain relief.