Quantification of Remimazolam Besylate (CNS7056B) and Its Metabolite (CNS7054X) by LC-MS/MS in Human Plasma Using Midazolam-d4 Maleate as Internal Standard

A new assay was developed to measure the concentration of remimazolam besylate (CNS7056B) and its major carboxylic acid metabolite (CNS7054X) in human plasma. For this new assay method, midazolam-d4 maleate was used as an internal standard. After setting up a previously described assay method, using CNS7056-d4 and CNS7054-d4 as internal standards, analytical results of both methods were compared. For the new analytical method, ultra-high-performance liquid chromatography (UHPLC) with tandem mass spectrometry was applied. A purification method, using solid phase extraction, was developed and validated. The chromatographic separation of the analytes was achieved with a mobile phase gradient using a Water Acquity™ UHPLC-System. The Kinetex™ biphenyl 50 × 2.1 mm UHPLC column was used with a particle diameter of 1.7 μm (Phenomenex, Germany). A measuring range of 0.6-2,000 ng/mL for CNS7056B and of 6-20,000 ng/mL for CNS7054X could be achieved with this new assay. The lower limit of quantification was 0.6 ng/mL for CNS7056B and 6 ng/mL for CNS7054X. The assay was validated according to US Food and Drug Administration guidelines. The new method showed an accuracy of 96.9-110.4% and a precision of 2.1-6.7% for both analytes.

Pharmacokinetics of remimazolam after intravenous infusion in anaesthetised children

BACKGROUND

The pharmacokinetic properties of the new benzodiazepine remimazolam have been studied only in adults. We investigated the pharmacokinetics of remimazolam after i.v. infusion in anaesthetised paediatric patients.

METHODS

Twenty-four children (2-6 yr, ASA physical status 1-2, BMI 15-18 kg m-2) undergoing general anaesthesia with sevoflurane were enrolled. During surgery, remimazolam was administered as an i.v. infusion over 1 h at 5 mg kg-1 h-1 for 5 min, followed by 1.5 mg kg-1 h-1 for 55 min. Plasma concentrations of remimazolam and its metabolite CNS7054 were determined from arterial blood samples using ultra-high performance liquid chromatography-mass spectrometry. Pharmacokinetic modelling was performed by population analysis.

RESULTS

Pharmacokinetics were best described by a three-compartment model for remimazolam and a two-compartment model for CNS7054 linked by a transit compartment. Remimazolam showed a high clearance of 15.9 (12.9, 18.2) ml kg-1 min-1 (median, Q25, Q75), a small central volume of distribution of 0.11 (0.08, 0.14) L kg-1 and a short terminal half-life of 67 (49, 85) min. The context-sensitive half-time after an infusion of 4 h was 17 (12, 21) min. The metabolite CNS7054 showed a low clearance of 0.89 (0.33, 1.40) ml kg-1 min-1, a small central volume of distribution of 0.011 (0.005, 0.016) L kg-1, and a long terminal half-life of 321 (230, 770) min.

CONCLUSIONS

Remimazolam in children was characterised by a high clearance and short context-sensitive half-time. When normalised to weight, pharmacokinetic properties were similar to those reported for adults.

CLINICAL TRIAL REGISTRATION

ChiCTR2200057629.

Interdisciplinary interactive blended learning concept in times of a pandemic - pain medicine "totally digital"

Introduction: Pain medicine is located in different sections of the medical curriculum. In the pandemic situation, an online teaching concept for Q14 which includes several disciplines had to be developed. The goal of the project was to create a fully digitized learning platform for the cross-sectional area Q14 that allows all participating disciplines to address the various learning goals without losing a practical component. Project description: First, the students' expectations regarding education in the field of pain medicine were recorded by means of a survey among medical students. Based on this, a teaching module in a blended learning format was developed, which consisted of two parts. Within a digital learning platform, students were first required to complete consecutive learning units using an interactive learning management system. This was followed by a presence phase (online ZOOM seminar) in which, under the guidance of teaching staff, the therapy suggestions of the individual case studies from the previous learning program were reflected. In the second part, the acquired knowledge was applied to a simulated patient. An evaluation of the online module was carried out through free-text answers and self-assessment of the completion time. The ZOOM seminar was evaluated on the basis of an assessment by the teachers. Results: The survey among students revealed a desire for practical training without "frontal teaching". The resulting project realized this aspect by teaching theory during an online module with case vignettes and interactive learning tasks. The subsequent online presence time during the ZOOM meeting enabled the students to repeat and deepen contents and to ask questions. 170 students completed the entire online program, of which evaluation data were available for 75 students. Self-assessment of completion time averaged at 4-6 hours. In the feedback, 90 aspects were addressed, including mainly comments on content (43%), praise (33%) and comments on technical problems (23%). According to the assessment of the presenters, the students were able to carry out the pain anamnesis survey in a structured manner. The submission of the therapy proposal, however, represents a particular hurdle. Conclusion: With the presented blended learning concept it is possible to address the different learning goals and the interdisciplinarity of Q14 sufficiently. After further processing and improvement of the project, a controlled and more extensive collection of evaluation data is required to further investigate the benefit of the platform for the students regarding achievement of defined learning goals.

General Anesthesia in the First 36 Months of Life–a Study of Cognitive Performance in Children Aged 7-11 Years (ANFOLKI-36)

BACKGROUND

Experimental data have shown that the developing brain is especially vulnerable to exogenous noxious substances. The potential effects of anesthetic drugs on brain growth and development are a matter of concern. Clinical studies of children who underwent general anesthesia in their earliest years can make a major contribution to our understanding of the effects of anesthetic drugs on infants and toddlers (i.e., children under age 5).

METHODS

Children born at term during the years 2007-2011 who were exposed to general anesthesia before their third birthday were included in the study. Data on general anesthesia were retrospectively evaluated, and the overall intelligence quotient (IQ) was determined prospectively as the primary target parameter. Children who had not been exposed to general anesthesia were recruited as a control group. The non-inferiority threshold was set at a difference of 5 IQ points out of a consideration of clinical relevance.

RESULTS

430 complete data sets were available from exposed children and 67 from members of the control group. The exposed group achieved a mean IQ score of 108.2, with a 95% confidence interval of [107; 109.4]; the corresponding values in the control group were 113 [110; 116.1]. Both groups achieved a mean score that was higher than the expected 100 points. After adjustment for age, socioeconomic status, and sex, the difference between the two groups was 2.9 points [0.2; 5.6], indicating a significantly better outcome in the control group than in the exposed group. The non-inferiority threshold of 5 IQ points was within the confidence interval; thus, non-inferiority was not demonstrated.

CONCLUSION

The fact that both groups achieved a higher IQ score than the expected 100 points may be attributable, at least in part, to the restriction of the study to children born at term. The results indicate that general anesthesia in early childhood is not associated with markedly reduced intelligence in later years, although non-inferiority could not be demonstrated.

Pharmacokinetics of Morphine and Morphine-6-Glucuronide During Postoperative Pain Therapy in Cardiac Surgery Patients

BACKGROUND AND OBJECTIVE

Morphine is a standard analgesic drug for postoperative pain therapy. This study aimed to evaluate the pharmacokinetics of morphine and its active metabolite morphine-6-glucuronide (M6G) in cardiac surgery  patients during postoperative analgesia.

METHODS

Twenty-five adult patients undergoing cardiac surgery received postoperative pain therapy by patient-controlled analgesia with intravenous bolus doses of morphine. Plasma concentrations of morphine and M6G were determined from arterial samples. Population pharmacokinetic parameters were estimated using nonlinear mixed-effects modeling.

RESULTS

Data from twenty-one patients (aged 44-79 years) were analyzed. Pharmacokinetics were best described by a three-compartment model for morphine and a two-compartment model for M6G, linked by a transit compartment. Mean (±SD) population estimates for morphine were: clearance (CL) = 1.35±0.40 L/min, central volume of distribution (V₁) = 8.1±2.2 L, steady-state volume of distribution (V_ss) = 207±83 L, terminal elimination half-life (T_1/2γ) = 177±50 min. Clearance of morphine was proportional to cardiac output. Mean (±SD) population estimates for M6G were: CL = 0.098±0.037 L/min, V₁ = 5.5±0.8 L, V_ss = 15.8±0.8 L, T_1/2β = 227±74 min. The time to peak concentration of M6G after a bolus dose of morphine was 53±20 min. Clearance of M6G was proportional to estimated glomerular filtration rate.

CONCLUSIONS

The pharmacokinetics of morphine and M6G in pain therapy of cardiac surgery  patients could be well described by standard compartmental models. Cardiac output was identified as a significant covariate for morphine clearance, whereas renal function was identified as the most significant covariate for clearance of M6G. These effects should be particularly considered if morphine is administered as a continuous infusion. The developed pharmacokinetic model also enables patient-controlled target-controlled infusion for pain therapy with morphine.

TRIAL REGISTRATION

Clinical Trials NCT02483221 (June 26, 2015).

Reduced Rate of Inpatient Hospital Admissions in 18 German University Hospitals During the COVID-19 Lockdown

The COVID-19 pandemic has caused strains on health systems worldwide disrupting routine hospital services for all non-COVID patients. Within this retrospective study, we analyzed inpatient hospital admissions across 18 German university hospitals during the 2020 lockdown period compared to 2018. Patients admitted to hospital between January 1 and May 31, 2020 and the corresponding periods in 2018 and 2019 were included in this study. Data derived from electronic health records were collected and analyzed using the data integration center infrastructure implemented in the university hospitals that are part of the four consortia funded by the German Medical Informatics Initiative. Admissions were grouped and counted by ICD 10 chapters and specific reasons for treatment at each site. Pooled aggregated data were centrally analyzed with descriptive statistics to compare absolute and relative differences between time periods of different years. The results illustrate how care process adoptions depended on the COVID-19 epidemiological situation and the criticality of the disease. Overall inpatient hospital admissions decreased by 35% in weeks 1 to 4 and by 30.3% in weeks 5 to 8 after the lockdown announcement compared to 2018. Even hospital admissions for critical care conditions such as malignant cancer treatments were reduced. We also noted a high reduction of emergency admissions such as myocardial infarction (38.7%), whereas the reduction in stroke admissions was smaller (19.6%). In contrast, we observed a considerable reduction in admissions for non-critical clinical situations, such as hysterectomies for benign tumors (78.8%) and hip replacements due to arthrosis (82.4%). In summary, our study shows that the university hospital admission rates in Germany were substantially reduced following the national COVID-19 lockdown. These included critical care or emergency conditions in which deferral is expected to impair clinical outcomes. Future studies are needed to delineate how appropriate medical care of critically ill patients can be maintained during a pandemic.

The TLR9 Agonist Cobitolimod Induces IL10-Producing Wound Healing Macrophages and Regulatory T Cells in Ulcerative Colitis

BACKGROUND AND AIMS

The topically applied Toll-like receptor 9 [TLR9] agonist cobitolimod is a first-in-class DNA-based oligonucleotide with demonstrated therapeutic efficacy in clinical trials with ulcerative colitis [UC] patients. We here characterized its anti-inflammatory mechanism in UC.

METHODS

Luminal cobitolimod administration was evaluated in an experimental dextran sodium sulfate [DSS]-induced colitis model. Cultured blood and mucosal cells from UC patients were treated with cobitolimod and analysed via microarray, quantitative real-time PCR, ELISA and flow cytometry. Intestinal slides of cobitolimod-treated UC patients were analysed by immunohistochemistry.

RESULTS

Cobitolimod administration markedly suppressed experimental colitis activity, and microarray analyses demonstrated mucosal IL10 upregulation and suppression of IL17 signalling pathways. Cobitolimod treatment was associated with significant induction of mucosal IL10+Tr1 and Treg cells and suppression of Th17 cells. TLR9 knockout mice indicated that cobitolimod requires TLR9 signalling for IL10 induction. In UC patients, mucosal TLR9 levels correlated with severity of inflammation. Cobitolimod inhibited IL17A and IL17F, but increased IL10 and FoxP3 expression in cultured intestinal UC T cells. Cobitolimod-mediated suppression of intestinal IL17+T cells was abrogated by IL10 blockade. Furthermore, cobitolimod led to heightened IL10 production by wound healing macrophages. Immunohistochemistry in intestinal biopsies of cobitolimod-treated UC patients indicated increased presence of IL10+mononuclear and regulatory T cells, as well as reduction of IL17+cells.

CONCLUSION

Activation of TLR9 via cobitolimod might represent a novel therapeutic approach in UC, as it suppresses Th17 cells and induces anti-inflammatory IL10+macrophages and regulatory T cells, thereby modifying the dysregulated intestinal cytokine balance.

PODCAST

This article has an associated podcast which can be accessed at https://academic.oup.com/ecco-jcc/pages/podcast.

β1 and β3 subunits amplify mechanosensitivity of the cardiac voltage-gated sodium channel Nav1.5

In cardiomyocytes, electrical activity is coupled to cellular contraction, thus exposing all proteins expressed in the sarcolemma to mechanical stress. The voltage-gated sodium channel Nav1.5 is the main contributor to the rising phase of the action potential in the heart. There is growing evidence that gating and kinetics of Nav1.5 are modulated by mechanical forces and pathogenic variants that affect mechanosensitivity have been linked to arrhythmias. Recently, the sodium channel β1 subunit has been described to stabilise gating against mechanical stress of Nav1.7 expressed in neurons. Here, we tested the effect of β1 and β3 subunits on mechanosensitivity of the cardiac Nav1.5. β1 amplifies stress-induced shifts of V_1/2 of steady-state fast inactivation to hyperpolarised potentials (ΔV_1/2: 6.2 mV without and 10.7 mV with β1 co-expression). β3, on the other hand, almost doubles stress-induced speeding of time to sodium current transient peak (Δtime to peak at - 30 mV: 0.19 ms without and 0.37 ms with β3 co-expression). Our findings may indicate that in cardiomyocytes, the interdependence of electrical activity and contraction is used as a means of fine tuning cardiac sodium channel function, allowing quicker but more strongly inactivating sodium currents under conditions of increased mechanical stress. This regulation may help to shorten action potential duration during tachycardia, to prevent re-entry phenomena and thus arrhythmias.

Pharmacokinetics of Intranasally Administered Dexmedetomidine in Chinese Children

Background: Intranasal application is a comfortable, effective, nearly non-invasive, and easy route of administration in children. To date, there is, however, only one pharmacokinetic study on intranasal dexmedetomidine in pediatric populations and none in Chinese children available. Therefore, this study aimed to characterize the pharmacokinetics of intranasally administered dexmedetomidine in Chinese children.

Methods: Thirteen children aged 4 to 10 years undergoing surgery received 1 µg/kg dexmedetomidine intranasally. Arterial blood samples were drawn at various time points until 180 min after dose. Dexmedetomidine plasma concentrations were measured with high performance liquid chromatography (HPLC) and mass spectrometry. Pharmacokinetic modeling was performed by population analysis using linear compartment models with first-order absorption.

Results: An average peak plasma concentration of 748 ± 30 pg/ml was achieved after 49.6 ± 7.2 min. The pharmacokinetics of dexmedetomidine was best described by a two-compartment model with first-order absorption and an allometric scaling with estimates standardized to 70-kg body weight. The population estimates (SE) per 70 kg bodyweight of the apparent pharmacokinetic parameters were clearance CL/F = 0.32 (0.02) L/min, central volume of distribution V1/F = 34.2 (4.9) L, intercompartmental clearance Q2/F = 10.0 (2.2) L/min, and peripheral volume of distribution V2/F = 34.9 (2.3) L. The estimated absorption rate constant was Ka = 0.038 (0.004) min⁻¹.

Conclusions: When compared with studies in Caucasians, Chinese children showed a similar time to peak plasma concentration after intranasal administration, but the achieved plasma concentrations were about three times higher. Possible reasons are differences in age, ethnicity, and mode of administration.

Pain relief in a neuropathy patient by lacosamide: Proof of principle of clinical translation from patient-specific iPS cell-derived nociceptors

BACKGROUND

Small fiber neuropathy (SFN) is a severe and disabling chronic pain syndrome with no causal and limited symptomatic treatment options. Mechanistically based individual treatment is not available. We report an in-vitro predicted individualized treatment success in one therapy-refractory Caucasian patient suffering from SFN for over ten years.

METHODS

Intrinsic excitability of human induced pluripotent stem cell (iPSC) derived nociceptors from this patient and respective controls were recorded on multi-electrode (MEA) arrays, in the presence and absence of lacosamide. The patient's pain ratings were assessed by a visual analogue scale (10: worst pain, 0: no pain) and treatment effect was objectified by microneurography recordings of the patient's single nerve C-fibers.

FINDINGS

We identified patient-specific changes in iPSC-derived nociceptor excitability in MEA recordings, which were reverted by the FDA-approved compound lacosamide in vitro. Using this drug for individualized treatment of this patient, the patient's pain ratings decreased from 7.5 to 1.5. Consistent with the pain relief reported by the patient, microneurography recordings of the patient's single nerve fibers mirrored a reduced spontaneous nociceptor (C-fiber) activity in the patient during lacosamide treatment. Microneurography recordings yielded an objective measurement of altered peripheral nociceptor activity following treatment.

INTERPRETATION

Thus, we are here presenting one example of successful patient specific precision medicine using iPSC technology and individualized therapeutic treatment based on patient-derived sensory neurons.

MIRACUM: Medical Informatics in Research and Care in University Medicine

INTRODUCTION

This article is part of the Focus Theme of Methods of Information in Medicine on the German Medical Informatics Initiative. Similar to other large international data sharing networks (e.g. OHDSI, PCORnet, eMerge, RD-Connect) MIRACUM is a consortium of academic and hospital partners as well as one industrial partner in eight German cities which have joined forces to create interoperable data integration centres (DIC) and make data within those DIC available for innovative new IT solutions in patient care and medical research.

OBJECTIVES

Sharing data shall be supported by common interoperable tools and services, in order to leverage the power of such data for biomedical discovery and moving towards a learning health system. This paper aims at illustrating the major building blocks and concepts which MIRACUM will apply to achieve this goal.

GOVERNANCE AND POLICIES

Besides establishing an efficient governance structure within the MIRACUM consortium (based on the steering board, a central administrative office, the general MIRACUM assembly, six working groups and the international scientific advisory board), defining DIC governance rules and data sharing policies, as well as establishing (at each MIRACUM DIC site, but also for MIRACUM in total) use and access committees are major building blocks for the success of such an endeavor.

ARCHITECTURAL FRAMEWORK AND METHODOLOGY

The MIRACUM DIC architecture builds on a comprehensive ecosystem of reusable open source tools (MIRACOLIX), which are linkable and interoperable amongst each other, but also with the existing software environment of the MIRACUM hospitals. Efficient data protection measures, considering patient consent, data harmonization and a MIRACUM metadata repository as well as a common data model are major pillars of this framework. The methodological approach for shared data usage relies on a federated querying and analysis concept.

USE CASES

MIRACUM aims at proving the value of their DIC with three use cases: IT support for patient recruitment into clinical trials, the development and routine care implementation of a clinico-molecular predictive knowledge tool, and molecular-guided therapy recommendations in molecular tumor boards.

RESULTS

Based on the MIRACUM DIC release in the nine months conceptual phase first large scale analysis for stroke and colorectal cancer cohorts have been pursued.

DISCUSSION

Beyond all technological challenges successfully applying the MIRACUM tools for the enrichment of our knowledge about diagnostic and therapeutic concepts, thus supporting the concept of a Learning Health System will be crucial for the acceptance and sustainability in the medical community and the MIRACUM university hospitals.

Towards Implementation of OMOP in a German University Hospital Consortium

Background  In 2015, the German Federal Ministry of Education and Research initiated a large data integration and data sharing research initiative to improve the reuse of data from patient care and translational research. The Observational Medical Outcomes Partnership (OMOP) common data model and the Observational Health Data Sciences and Informatics (OHDSI) tools could be used as a core element in this initiative for harmonizing the terminologies used as well as facilitating the federation of research analyses across institutions.

Objective  To realize an OMOP/OHDSI-based pilot implementation within a consortium of eight German university hospitals, evaluate the applicability to support data harmonization and sharing among them, and identify potential enhancement requirements.

Methods  The vocabularies and terminological mapping required for importing the fact data were prepared, and the process for importing the data from the source files was designed. For eight German university hospitals, a virtual machine preconfigured with the OMOP database and the OHDSI tools as well as the jobs to import the data and conduct the analysis was provided. Last, a federated/distributed query to test the approach was executed.

Results  While the mapping of ICD-10 German Modification succeeded with a rate of 98.8% of all terms for diagnoses, the procedures could not be mapped and hence an extension to the OMOP standard terminologies had to be made.

Overall, the data of 3 million inpatients with approximately 26 million conditions, 21 million procedures, and 23 million observations have been imported.

A federated query to identify a cohort of colorectal cancer patients was successfully executed and yielded 16,701 patient cases visualized in a Sunburst plot.

Conclusion  OMOP/OHDSI is a viable open source solution for data integration in a German research consortium. Once the terminology problems can be solved, researchers can build on an active community for further development.

[Does annual simulation training influence the safety climate of a university hospital? : Prospective 5‑year investigation using dimensions of the safety attitude questionnaire]

BACKGROUND

Simulation-based training with a focus on non-technical skills can have a positive influence on safety relevant attitudes of participants. If an organization succeeds in training sufficient staff, it may experience a positive change in the safety climate. As the effects of a single training are of a transient nature, annual training sessions may lead to an incremental improvement of safety relevant attitudes of employees over time. In spring 2012 the Department of Anesthesia at the University Hospital of Erlangen established an annual simulation-based training for staff members (e.g. consultants, trainee anesthetists and nurse anesthetists).

OBJECTIVE

The study aimed to test whether an annual simulation-based training would result in an incremental longitudinal improvement in attitudes towards teamwork, safety and stress recognition.

METHODS

A survey comprising three domains (teamwork climate, safety climate and stress recognition) of the safety attitudes questionnaire (SAQ) and items addressing briefing and speaking up was distributed to all participants in an annual in-house simulation training. Participants filled out the questionnaire in the morning of each training day. The attitudes were measured before the first training series in 2012, 6 months after the first training and then every year (2013-2016). Participants generated a personalized identification code which allowed individuals to be anonymously tracked over time. Results of the 5‑point Likert scale were transformed to a 100-point scale. Results were calculated at the group level and at the individual level. Univariable linear regression was used to calculate mean changes per year.

RESULTS

Over a period of 5 years (2012-2016) a total of 255 individuals completed the questionnaire. Each year, 14-20% of all nurse anesthetists and 81-90% of all anesthetists participated in the simulation-based training. As a result of annual staff turnover 16-24% of participants were new staff members. A personalized code allowed the before and after comparison of 99 staff members who had participated twice or more. Physicians had a higher mean score for teamwork climate before the first training (+8.7 p < 0.001). Mean teamwork climate and safety climate scores before the first training increased over a period of 5 years (3.11 for teamwork climate, p < 0.001 and 2.73 for safety climate, p < 0.001). Repeat participation led to a bigger mean change of individual attitudes in nurse anesthetists: teamwork climate 5.2 (nurses) vs. 1.4 (physicians) and safety climate 5.3 (nurses) vs. 2.8 (physicians) without reaching significance. Participants acknowledged the importance of briefings but confirmed their existence in less than half of the cases. The frequency of briefings increased over the 5‑year period. There were no changes in attitude towards speaking up.

CONCLUSION

Over a 5-year period, small positive changes in attitudes towards teamwork and safety occurred. Low participation of nurse anesthetists as well as personnel turnover may have weakened the impact of simulation-based training on the safety climate.

Population Pharmacokinetics of Dexmedetomidine After Short Intravenous Infusion in Chinese Children

BACKGROUND AND OBJECTIVE

Dexmedetomidine is a highly selective alpha2-adrenoceptor agonist with sedative and analgesic properties which is also used in pediatric anesthesia. Although the pharmacokinetics of dexmedetomidine have been studied in pediatric patients, there are no data for Chinese children available. As alterations in pharmacokinetics due to ethnicity cannot be ruled out, it was the aim of this study to characterize the pharmacokinetics of dexmedetomidine in Chinese pediatric patients.

METHODS

Thirty-nine children aged 1-9 years undergoing surgery were enrolled in the study. Dexmedetomidine was administered as short intravenous infusion of 1-2 µg/kg in 10 min. Venous blood samples were drawn until 480 min after stopping of infusion. Dexmedetomidine plasma concentrations were measured with high-performance liquid chromatography and mass spectrometry. Pharmacokinetic modeling was performed by population analysis using linear compartment models.

RESULTS

Data of 36 patients (age 1-9 years, weight 10-27 kg) were analyzed. The pharmacokinetics of dexmedetomidine were best described by a two-compartment model with an allometric power model and estimates standardized to 70 kg body weight. The population estimates (95 % CI) per 70 kg bodyweight were: clearance 36.2 (33.3-41.1) l/h, central volume of distribution 84.3 (70.3-91.4) l, intercompartmental clearance 82.8 (63.6-136.6) l/h, peripheral volume of distribution 114 (95-149) l, and terminal half-life 4.4 (3.6-5.3) h. Age did not show any influence on weight-adjusted parameters.

CONCLUSIONS

Chinese children showed a similar clearance, but larger volumes of distribution and longer terminal half-life when compared to studies in Caucasians.

TRIAL REGISTRATION

ChiCTR-OPC-14005659.

Determination of total and unbound propofol in patients during intensive care sedation by ultrafiltration and LC-MS/MS

For the quantification of propofol total and unbound drug concentrations a sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated. To separate unbound propofol an ultrafiltration step before sample preparation was performed. Both the ultrafiltrate and plasma samples were extracted with solid-phase extraction and substituted with deuterated propofol as an internal standard. Separation was performed by gradient elution using UPLC-like system and analyzed by MS/MS consisting of an electrospray ionization source. To detect low and high concentration levels of propofol two calibration curves were identified and showed linearity within the range of 1-50ng/ml and 50-20000ng/ml. The lower limit of quantification was 1ng/ml. Intra- and interassay precision and accuracy did not exceed ±15%. The method was applied to a clinical study during intensive care treatment of patients after coronary artery bypass grafting.

External Validation of a Recently Developed Population Pharmacokinetic Model for Hydromorphone During Postoperative Pain Therapy

BACKGROUND AND OBJECTIVE

We recently developed a new population pharmacokinetic model for hydromorphone in patients including age and bodyweight as covariates. The aim of the present study was to evaluate prospectively the predictive performance of this new model during postoperative pain therapy.

METHODS

This was a prospective, single-blinded, randomized, single-center study with two parallel arms. Fifty patients aged 40-85 years undergoing cardiac surgery involving thoracotomy were enrolled. Hydromorphone was administered postoperatively on the intensive care unit as target controlled infusion (TCI) for patient controlled analgesia (TCI-PCA) using the new pharmacokinetic model, or as conventional patient controlled analgesia (PCA). Arterial blood samples were taken for measurement of the hydromorphone plasma concentration. The predictive performance of the pharmacokinetic model was assessed by the median performance error (MDPE), the median absolute performance error (MDAPE), wobble and divergence. For comparison, the performance indices were also determined for three older models from the literature.

RESULTS

903 plasma concentrations of 41 patients were analyzed. The mean values (95 % CI) of MDPE, MDAPE, wobble and divergence for the new pharmacokinetic model were 11.2 % (3.9 to 18.7 %), 28.5 % (23.9 to 33.0 %), 21.4 % (18.0 to 24.9 %) and -1.6 %/h (-2.3 to -0.8 %/h). When compared with older models from the literature, performance was better with less overshoot after bolus doses.

CONCLUSION

The new pharmacokinetic model of hydromorphone showed a good precision and a better performance than older models. It is therefore suitable for TCI with hydromorphone during postoperative pain therapy.

TRIAL REGISTRATION

EudraCT 2013-002875-16, Clinical Trials NCT02035709.

Septic cardiomyopathy in rat LPS-induced endotoxemia: relative contribution of cellular diastolic Ca(2+) removal pathways, myofibrillar biomechanics properties and action of the cardiotonic drug levosimendan

Cardiac dysfunction is a common complication in sepsis and is characterized by forward pump failure. Hallmarks of septic cardiomyopathy are decreased myofibrillar contractility and reduced Ca(2+) sensitivity but it is still not clear whether reduced pump efficiency is predominantly a diastolic impairment. Moreover, a comprehensive picture of upstream Ca(2+) handling mechanisms and downstream myosin biomechanical parameters is still missing. Ca(2+)-sensitizing agents in sepsis may be promising but mechanistic insights for drugs like levosimendan are scarce. Here, we used an endotoxemic LPS rat model to study mechanisms of sepsis on in vivo hemodynamics, multicellular myofibrillar Ca(2+) sensitivity, in vitro cellular Ca(2+) homeostasis and subcellular actomyosin interaction with intracardiac catheters, force transducers, confocal Fluo-4 Ca(2+) recordings in paced cardiomyocytes, and in vitro motility assay, respectively. Left ventricular ejection fraction and myofibrillar Ca(2+) sensitivity were depressed in LPS animals but restored by levosimendan. Diastolic Ca(2+) transient kinetics was slowed down by LPS but ameliorated by levosimendan. Selectively blocking intracellular and sarcolemmal Ca(2+) extrusion pathways revealed minor contribution of sarcoplasmic reticulum Ca(2+) ATPase (SERCA) to Ca(2+) transient diastole in LPS-evoked sepsis but rather depressed Na(+)/Ca(2+) exchanger and plasmalemmal Ca(2+) ATPase. This was mostly compensated by levosimendan. Actin sliding velocities were depressed in myosin heart extracts from LPS rats. We conclude that endotoxemia specifically impairs sarcolemmal diastolic Ca(2+) extrusion pathways resulting in intracellular diastolic Ca(2+) overload. Levosimendan, apart from stabilizing Ca(2+)-troponin C complexes, potently improves cellular Ca(2+) extrusion in the septic heart.

Influence of intensive care treatment on the protein binding of sufentanil and hydromorphone during pain therapy in postoperative cardiac surgery patients

BACKGROUND

Our objective was to evaluate the effect of intensive care treatment on the protein binding of sufentanil and hydromorphone in cardiac surgery patients during postoperative analgesia using a target-controlled infusion (TCI) and patient-controlled analgesia (PCA).

METHODS

Fifty adult patients were enrolled in this prospective randomized study; of which, 49 completed the study (age range 40-81 yr). Sufentanil was administered as an analgesic intraoperatively, and hydromorphone was dosed after operation with TCI and PCA until 8 a.m. on the first postoperative day. Arterial plasma samples were collected for drug and protein concentration measurements up to 24 h after cardiac surgery. Corresponding patient data were collected from the electronic patient data system. After explorative data analysis with principal component analysis, multivariate regression analysis and non-linear mixed effects modelling was used to study the effect of treatment on protein binding.

RESULTS

Data of 35 patients were analysed. The median protein binding of sufentanil and hydromorphone was 88.4% (IQ range 85.7-90.5%) and 11.6% (IQ range 9.5-14.3%), respectively. Free fraction of sufentanil increased towards the end of the study period, whereas hydromorphone free fraction remained nearly constant. The total sufentanil concentration and volume balance were identified as significant covariates for the protein binding of sufentanil. For the protein binding of hydromorphone, no significant covariate effects were found.

CONCLUSIONS

Sufentanil protein binding was significantly dependent on changes in the total drug concentration and volume balance addressing the importance of adequate dosing and fluid-guided therapy. Hydromorphone protein binding was nearly constant throughout the study period.

CLINICAL TRIAL REGISTRATION

EudraCT 2011-003648-31 and ClinicalTrials.gov: NCT01490268.

A randomized open-label phase I pilot study of the safety and efficacy of total intravenous anesthesia with fospropofol for coronary artery bypass graft surgery

OBJECTIVE

To determine safety and efficacy of the water-soluble prodrug fospropofol for anesthesia in cardiac surgery and to compare the pharmacodynamic profiles of fospropofol and propofol.

DESIGN

Pilot study and a prospective, phase I, open-label, single-center, randomized clinical trial.

SETTING

University hospital; single institution.

PARTICIPANTS

Sixteen patients undergoing elective first-time coronary artery bypass surgery.

INTERVENTIONS

Patients were randomized to receive total intravenous anesthesia with fospropofol (n = 8) or propofol (n = 8) combined with alfentanil as total intravenous anesthesia. Bispectral index, arterial blood pressure, and heart rate were recorded continuously, and pulmonary artery catheter measurements were obtained. Plasma concentrations of formate, phosphate, and Ca(2+) were monitored closely. Safety and tolerability were assessed by adverse events, neurologic examinations, clinical laboratory tests, and vital signs.

MEASUREMENTS AND MAIN RESULTS

The total doses of fospropofol and propofol during anesthesia were 11.3±2.5 and 4.4±1.0 mg/kg/h, respectively. According to the achieved bispectral index (BIS) values, fospropofol was as effective as propofol in providing general anesthesia and sedation. There were no clinical signs of formate toxicity in the fospropofol group. The only treatment-related adverse event after administration of fospropofol was a transient burning sensation in the perineal and perianal region during induction of sedation or anesthesia.

CONCLUSIONS

Fospropofol could be used to provide general anesthesia in patients undergoing coronary artery bypass graft surgery. Further larger studies are needed to prove the safety of fospropofol when given to provide general anesthesia for major cardiac surgical procedures.

[Implementation of a patient data management system. Effects on intensive care documentation]

BACKGROUND

Patient data management systems (PDMS) enable digital documentation on intensive care units (ICU). A commercial PDMS was implemented in a 25-bed ICU replacing paper-based patient charting. The ICU electronic patient record is completely managed inside the PDMS. It compiles data from vital signs monitors, ventilators and further medical devices and facilitates some drug dose and fluid balance calculations as well as data reuse for administrative purposes. Ventilation time and patient severity scoring as well as coding of diagnoses and procedures is supported. Billing data transferred via interface to the central billing system of the hospital. Such benefits should show in measurable parameters, such as documented ventilator time, number of coded diagnoses and procedures and others. These parameters influence reimbursement in the German DRG system. Therefore, measurable changes in cost and reimbursement data of the ICU were expected.

MATERIAL AND METHODS

A retrospective analysis of documentation quality parameters, cost data and mortality rate of a 25-bed surgical ICU within a German university hospital 3 years before (2004-2006) and 5 years after (2007-2011) PDMS implementation. Selected parameters were documented electronically, consistently and reproducibly for the complete time span of 8 years including those years where no electronic patient recording was available. The following parameters were included: number of cleared DRG, cleared ventilator time, case mix (CM), case mix index (CMI), length of stay, number of coded diagnoses and procedures, detailed overview of a specific procedure code based on daily Apache II and TISS Core 10 scores, mortality, total ICU costs and revenues and partial profits for specific ICU procedures, such as renal replacement therapy and blood products.

RESULTS

Systematic shifts were detected over the study period, such as increasing case numbers and decreasing length of stay as well as annual fluctuations in severity of disease seen in the CM and CMI. After PDMS introduction, the total number of coded diagnoses increased but the proportion of DRG relevant diagnoses dropped significantly. The number of procedures increased (not significantly) and the number of procedures per case did not rise significantly. The procedure 8-980 showed a significant increase after PDMS introduction whereas the DRG-relevant proportion of those procedures dropped insignificantly. The number of ventilator-associated DRG cases as well as the total ventilator time increased but not significantly. Costs and revenues increased slightly but profit varied considerably from year to year in the 5 years after system implementation. A small increase was observed per case, per nursing day and per case mix point. Additional revenues for specific ICU procedures increased in the years before and dropped after PDMS implementation. There was an insignificant increase in ICU mortality rate from 7.4 % in the year 2006 (before) to 8.5 % in 2007 (after PDMS implementation). In the following years mortality dropped below the base level.

CONCLUSION

The implementation of the PDMS showed only small effects on documentation of reimbursement-relevant parameters which were too small to set off against the total investment. The method itself, a long-term follow-up of different parameters proved successful and can be adapted by other organizations. The quality of results depends on the availability of long-term parameters in good quality. No significant influence of PDMS on mortality was found.

Does introduction of a Patient Data Management System (PDMS) improve the financial situation of an intensive care unit?

BACKGROUND

Patient Data Management Systems (PDMS) support clinical documentation at the bedside and have demonstrated effects on completeness of patient charting and the time spent on documentation. These systems are costly and raise the question if such a major investment pays off. We tried to answer the following questions: How do costs and revenues of an intensive care unit develop before and after introduction of a PDMS? Can higher revenues be obtained with improved PDMS documentation? Can we present cost savings attributable to the PDMS?

METHODS

Retrospective analysis of cost and reimbursement data of a 25 bed Intensive Care Unit at a German University Hospital, three years before (2004-2006) and three years after (2007-2009) PDMS implementation.

RESULTS

Costs and revenues increased continuously over the years. The profit of the investigated ICU was fluctuating over the years and seemingly depending on other factors as well. We found a small increase in profit in the year after the introduction of the PDMS, but not in the following years. Profit per case peaked at 1039 € in 2007, but dropped subsequently to 639 € per case. We found no clear evidence for cost savings after the PDMS introduction. Our cautious calculation did not consider additional labour costs for IT staff needed for system maintenance.

CONCLUSIONS

The introduction of a PDMS has probably minimal or no effect on reimbursement. In our case the observed increase in profit was too small to amortize the total investment for PDMS implementation.This may add some counterweight to the literature, where expectations for tools such as the PDMS can be quite unreasonable.

Evaluation of techniques for estimating the power spectral density of RR-intervals under paced respiration conditions

Heart rate variability (HRV) analysis is increasingly used in anaesthesia and intensive care monitoring of spontaneous breathing and mechanical ventilated patients. In the frequency domain, different estimation methods of the power spectral density (PSD) of RR-intervals lead to different results. Therefore, we investigated the PSD estimates of fast Fourier transform (FFT), autoregressive modeling (AR) and Lomb-Scargle periodogram (LSP) for 25 young healthy subjects subjected to metronomic breathing. The optimum method for determination of HRV spectral parameters under paced respiration was identified by evaluating the relative error (RE) and the root mean square relative error (RMSRE) for each breathing frequency (BF) and spectral estimation method. Additionally, the sympathovagal balance was investigated by calculating the low frequency/high frequency (LF/HF) ratio. Above 7 breaths per minute, all methods showed a significant increase in LF/HF ratio with increasing BF. On average, the RMSRE of FFT was lower than for LSP and AR. Therefore, under paced respiration conditions, estimating RR-interval PSD using FFT is recommend.

Secondary use of routinely collected patient data in a clinical trial: an evaluation of the effects on patient recruitment and data acquisition

PURPOSE

Clinical trials are time-consuming and require constant focus on data quality. Finding sufficient time for a trial is a challenging task for involved physicians, especially when it is conducted in parallel to patient care. From the point of view of medical informatics, the growing amount of electronically available patient data allows to support two key activities: the recruitment of patients into the study and the documentation of trial data.

METHODS

The project was carried out at one site of a European multicenter study. The study protocol required eligibility assessment for 510 patients in one week and the documentation of 46-186 data elements per patient. A database query based on routine data from patient care was set up to identify eligible patients and its results were compared to those of manual recruitment. Additionally, routine data was used to pre-populate the paper-based case report forms and the time necessary to fill in the remaining data elements was compared to completely manual data collection.

RESULTS

Even though manual recruitment of 327 patients already achieved high sensitivity (88%) and specificity (87%), the subsequent electronic report helped to include 42 (14%) additional patients and identified 21 (7%) patients, who were incorrectly included. Pre-populating the case report forms decreased the time required for documentation from a median of 255 to 30s.

CONCLUSIONS

Reuse of routine data can help to improve the quality of patient recruitment and may reduce the time needed for data acquisition. These benefits can exceed the efforts required for development and implementation of the corresponding electronic support systems.

Effects of intermittent hemodialysis on buprenorphine and norbuprenorphine plasma concentrations in chronic pain patients treated with transdermal buprenorphine

The present study was designed to study the impact of intermittent hemodialysis on the disposition of the partial agonist buprenorphine and its metabolite norbuprenorphine during therapy with transdermal buprenorphine in chronic pain patients with end-stage kidney disease. Ten patients (mean age 63 years) who had received transdermal buprenorphine for at least 1 week, were asked to provide blood samples immediately before and after hemodialysis. Blood samples were analysed for buprenorphine and its metabolite norbuprenorphine. The median buprenorphine plasma concentrations were found to be 0.16 ng/ml before and 0.23 ng/ml after hemodialysis. A significant correlation between plasma levels and administered doses was observed (Spearman R=0.74; P<0.05). In three patients norbuprenorphine plasma levels were detected. No differences in pain relief before and after hemodialysis were observed. This investigation shows no elevated buprenorphine and norbuprenorphine plasma levels in patients with renal insufficiency receiving transdermal buprenorphine up to 70 microg/h. Furthermore, hemodialysis did not affect buprenorphine plasma levels, leading to stable analgesic effects during the therapy.

Equipment for pre-hospital airway management on Helicopter Emergency Medical System helicopters in central Europe

BACKGROUND

For advanced out-of-hospital airway management, skilled personnel and adequate equipment are key prerequisites. There are little data on the current availability of airway management equipment and standards of medical staff on Helicopter Emergency Medical System (HEMS) helicopters in central Europe.

METHODS

An internet search identified all HEMS helicopters in Austria, Switzerland and Luxembourg. We identified 15 HEMS helicopter bases in Switzerland, 28 in Austria and three in Luxembourg. A questionnaire was sent to all bases, asking both for the details of the clinical background and experience of participating staff, and details of airway management equipment carried routinely on board.

RESULTS

Replies were received from 14 helicopter bases in Switzerland (93%), 25 bases in Austria (89%) and all three bases in Luxembourg. Anaesthesiologists were by far the most frequent attending physicians (68-85%). All except one bases reported to have at least one alternative supraglottic airway device. All bases had capnometry and succinylcholine. All bases in the study except two in Austria had commercial pre-packed sets for a surgical airway. All helicopters were equipped with automatic ventilators, although not all were suitable for non-invasive ventilation (NIV; Switzerland: 43%, Austria: 12%, Luxembourg: 100%). Masks for NIV were rarely available in Switzerland (two bases; 14%) and in Austria (three bases; 12%), whereas all three bases in Luxembourg carried those masks.

CONCLUSION

Most HEMS helicopters carry appropriate equipment to meet the demands of modern advanced airway management in the pre-hospital setting. Further work is needed to ensure that appropriate airway equipment is carried on all HEMS helicopters.

Evidence and consensus-based German guidelines for the management of analgesia, sedation and delirium in intensive care--short version

Targeted monitoring of analgesia, sedation and delirium, as well as their appropriate management in critically ill patients is a standard of care in intensive care medicine. With the undisputed advantages of goal-oriented therapy established, there was a need to develop our own guidelines on analgesia and sedation in intensive care in Germany and these were published as 2(nd) Generation Guidelines in 2005. Through the dissemination of these guidelines in 2006, use of monitoring was shown to have improved from 8 to 51% and the use of protocol-based approaches increased to 46% (from 21%). Between 2006-2009, the existing guidelines from the DGAI (Deutsche Gesellschaft für Anästhesiologie und Intensivmedizin) and DIVI (Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin) were developed into 3(rd) Generation Guidelines for the securing and optimization of quality of analgesia, sedation and delirium management in the intensive care unit (ICU). In collaboration with another 10 professional societies, the literature has been reviewed using the criteria of the Oxford Center of Evidence Based Medicine. Using data from 671 reference works, text, diagrams and recommendations were drawn up. In the recommendations, Grade "A" (very strong recommendation), Grade "B" (strong recommendation) and Grade "0" (open recommendation) were agreed. As a result of this process we now have an interdisciplinary and consensus-based set of 3(rd) Generation Guidelines that take into account all critically illness patient populations. The use of protocols for analgesia, sedation and treatment of delirium are repeatedly demonstrated. These guidelines offer treatment recommendations for the ICU team. The implementation of scores and protocols into routine ICU practice is necessary for their success.

Fospropofol disodium, a water-soluble prodrug of the intravenous anesthetic propofol (2,6-diisopropylphenol)

BACKGROUND

Today, propofol or 2,6-diisopropylphenol is the anesthetic mainly used for monitored anesthetic care sedation and during intravenous anesthesia. The formulation, a lipid macroemulsion, shows several disadvantages. Therefore, during the past years considerable scientific effort has been undertaken to find either a better formulation or a prodrug of propofol. Fospropofol is the first propofol prodrug that has been intensively studied in man. It has been licensed in 2008 by the FDA for monitored anesthetic care sedation.

OBJECTIVES AND METHODS

This review describes first published study results of fospropofol with regard to its pharmacokinetics/pharmacodynamics, drug safety, tolerability and drug side effects. Using a Medline search all published articles and abstracts containing the words fospropofol or GPI 15715 were included.

RESULTS AND CONCLUSION

As the impact of an errorness drug assay for propofol liberated from fospropofol is not exactly defined, no clear conclusions can be drawn from the first published pharmacokinetic/pharmacodynamic studies. Fospropofol was well tolerated in the first two clinical studies and no serious side effects were reported. After characterization of the true pharmacokinetic/pharmacodynamics profile, fospropofol, an aqueous solution, has the potential to favorably compare with benzodiazepines for procedural sedation and also may be used for long-term sedation and intravenous anesthesia.

[Airway management in the German air rescue service]

BACKGROUND

The equipment carried in rescue helicopters concerning airway management is not standardized in Germany. The current DIN/EN equipment regulations are not detailed for every single item resulting in differences between the various rescue bases. The aim of this survey was to show existing differences in airway management equipment.

METHODS

All 72 German air rescue helicopters listed in the ADAC air rescue stations atlas 2006/2007 received a questionnaire.

RESULTS

A total of 64 bases returned the questionnaire (88.9%). The most frequent types of supraglottic airway equipment were laryngeal masks (67.2%), Combitubes (32.8%) and laryngeal tubes (29.7%). Cricothyrotomy sets were more frequent (68.8%) than tracheostomy sets (35.9%). Of the bases 18.8% had masks suitable for non-invasive ventilation (NIV). All helicopters were equipped to carry out capnometry.

CONCLUSIONS

The rescue helicopters were found to have differences with respect to the equipment carried for airway management. Medical treatment according to current guidelines is possible on almost all bases.

Spinal endocannabinoids and CB1 receptors mediate C-fiber-induced heterosynaptic pain sensitization

Diminished synaptic inhibition in the spinal dorsal horn is a major contributor to chronic pain. Pathways that reduce synaptic inhibition in inflammatory and neuropathic pain states have been identified, but central hyperalgesia and diminished dorsal horn synaptic inhibition also occur in the absence of inflammation or neuropathy, solely triggered by intense nociceptive (C-fiber) input to the spinal dorsal horn. We found that endocannabinoids, produced upon strong nociceptive stimulation, activated type 1 cannabinoid (CB1) receptors on inhibitory dorsal horn neurons to reduce the synaptic release of gamma-aminobutyric acid and glycine and thus rendered nociceptive neurons excitable by nonpainful stimuli. Our results suggest that spinal endocannabinoids and CB1 receptors on inhibitory dorsal horn interneurons act as mediators of heterosynaptic pain sensitization and play an unexpected role in dorsal horn pain-controlling circuits.

Prehospital airway management on rescue helicopters in the United Kingdom

Adequate equipment is one prerequisite for advanced, out of hospital, airway management. There are no data on current availability of airway equipment on UK rescue helicopters. An internet search revealed all UK rescue helicopters, and a questionnaire was sent to the bases asking for available airway management items. We identified 27 helicopter bases and 26 (96%) sent the questionnaire back. Twenty-four bases (92%) had at least one supraglottic airway device; 16 (62%) helicopters had material for establishing a surgical airway (e.g. a cricothyroidotomy set); 88% of the helicopters had CO(2) detection; 25 (96%) helicopters carried automatic ventilators; among these, four (15%) had sophisticated ventilators and seven (27%) helicopters carried special face masks suitable for non-invasive ventilation. We found a wide variation in the advanced airway management equipment that was carried routinely on air ambulances. Current guidelines for airway management are not met by all UK air ambulances.

[Patient-controlled analgesia (PCA) in outpatients with cancer pain. Analysis of 1,692 treatment days]

INTRODUCTION

In the home-care setting, cancer pain patients in need of parenteral analgesia have to be switched to patient-controlled analgesia using portable pumps. But there is a paucity on data on the logistic requirements or the success rate of such a cost-intensive therapy performed by specialized home-care services.

METHODS

In a retrospective study we analyzed data on care intensity, logistics and outcome of 46 consecutive palliative cancer patients with patient-controlled analgesia (PCA) in a home-care setting.

RESULTS

On days 1, 2, and 3 of PCA the switch to parenteral analgesia resulted in a significant increase of the median daily opioid dose in comparison to the dose just prior to PCA. Concurrently, pain scores were significantly reduced. The median duration of PCA was 25 days (range 2-189 days). On average, each patient was seen by the home-care team every 7.4 days. The median duration of the home visits was 60 min (range, 10-190 min). Of the visits 20% were unscheduled, most of these visits being due to problems regarding analgesia. Most patients died at home. Insufficient analgesia required prefinal hospitalization in only a single case.

CONCLUSION

If the indications are correct, intravenous PCA for palliative cancer pain patients results in higher opioid consumption and better pain control. Home-care PCA requires a lot of human and financial resources, but pain-related hospitalization can be prevented.

[The DGAI CPR registry - the datasets "hospital care" and "long-term process"]

After several years of preparation the German Society of Anaesthesiology and Intensive Care Medicine (Deutsche Gesellschaft für Anästhesiologie und Intensivmedizin--DGAI) has, during its annual conference 2007, officially launched the DGAI CPR registry. After implementation of the dataset "primary care" in 2004, the datasets "definite care" and "long-term process" have now been released. The completed, internet based database is open for any interested person or institution as a tool for quality management. Data may be recorded online, and basic analyses be performed immediately. Beyond that benchmarks with other institutions are possible, by including the well accepted Utstein style on international level too.

Supra-additive effects of tramadol and acetaminophen in a human pain model ☆

The combination of analgesic drugs with different pharmacological properties may show better efficacy with less side effects. Aim of this study was to examine the analgesic and antihyperalgesic properties of the weak opioid tramadol and the non-opioid acetaminophen, alone as well as in combination, in an experimental pain model in humans. After approval of the local Ethics Committee, 17 healthy volunteers were enrolled in this double-blind and placebo-controlled study in a cross-over design. Transcutaneous electrical stimulation at high current densities (29.6+/-16.2 mA) induced spontaneous acute pain (NRS=6 of 10) and distinct areas of hyperalgesia for painful mechanical stimuli (pinprick-hyperalgesia). Pain intensities as well as the extent of the areas of hyperalgesia were assessed before, during and 150 min after a 15 min lasting intravenous infusion of acetaminophen (650 mg), tramadol (75 mg), a combination of both (325 mg acetaminophen and 37.5mg tramadol), or saline 0.9%. Tramadol led to a maximum pain reduction of 11.7+/-4.2% with negligible antihyperalgesic properties. In contrast, acetaminophen led to a similar pain reduction (9.8+/-4.4%), but a sustained antihyperalgesic effect (34.5+/-14.0% reduction of hyperalgesic area). The combination of both analgesics at half doses led to a supra-additive pain reduction of 15.2+/-5.7% and an enhanced antihyperalgesic effect (41.1+/-14.3% reduction of hyperalgesic areas) as compared to single administration of acetaminophen. Our study provides first results on interactions of tramadol and acetaminophen on experimental pain and hyperalgesia in humans. Pharmacodynamic modeling combined with the isobolographic technique showed supra-additive effects of the combination of acetaminophen and tramadol concerning both, analgesia and antihyperalgesia. The results might act as a rationale for combining both analgesics.