[Use of high-flow oxygen treatment in the emergency medical service: what are the dangers for users from the perspective of occupational and fire protection?] / Anwendung von "High-flow"-Sauerstoff-Therapie im Rettungsdienst: Welche Gefahren ergeben sich für Anwender aus der Perspektive des Arbeits- und Brandschutzes?

INTRODUCTION: The administration of high concentrations of oxygen may harm patients or paramedics by increasing the probability of fire. The presented work investigated the effect of oxygen applied via high flow in different concentrations and flow rates on environmental oxygen concentrations in the patient compartment of an ambulance. RESULTS: Environmental oxygen concentrations increased rapidly over time and oxygen is stored in blankets and clothes over a long period. Simulation in a fire laboratory showed that also in high oxygen concentration settings fire needs a flame or temperatures above 300 °C. Sparks alone were not able to start a fire. CONCLUSION: Ventilation of patient compartment and clothes with ambient air are mandatory to reduce dangerous oxygen concentrations in transport of patients on high-flow oxygen treatment.

Anaesthesia related complications - a single centre data analysis at a tertiary hospital in central Switzerland.

AIMS: Anaesthesia safety has improved over time with severe anaesthesia-related complications and death becoming rare events. We investigated anaesthesia-related complications over a period of 17 years in this single centre retrospective observational cohort study. The main aims were to assess the temporal trends of anaesthesia-related complications, their distribution among clinics and their relation to emergency versus non-emergency interventions. METHODS: In this retrospective, observational cohort study, anaesthesia and event protocols of patients who suffered from an anaesthesia-related complication were collected in the period from 1 January 2003 to 31 December 2019. These data sets were anonymised and grouped into demographic information, ASA physical status, information about dental status and hospital department. Out of the total of 257 cases that were reported to the department of anaesthesia at the Luzerner Kantonsspital, 110 were excluded as they were not anaesthesia-related and 14 because of incomplete reporting forms. The different complications were categorised by the severity injury scale score. The total number of anaesthetics during the study period amounted to 399,583. RESULTS: 133 patients with complications were included. Six patients died owing to a partially anaesthesia-related complication, two suffered from permanent damage, 62 had temporary symptoms and in 63 patients dental damage occurred. The temporal trend showed a major decrease in severe anaesthesia complications and deaths, whiledental injuries were the main complications after 2010. Most of the complications were reported in the orthopaedic department, whereas dental injuries were predominantly reported in the otorhinolaryngology department. The majority of complications occurred during elective surgery although this was not significant (p = 0.53). CONCLUSIONS: Severe anaesthesia-related complications and death decreased dramatically during the study period. Anaesthesia complications are not more frequent in emergency surgeries. Overall, complications occurred more frequently in orthopaedics, and dental injuries predominated in otorhinolaryngology.

Implementation and Evaluation of a Web-Based Distribution System For Anesthesia Department Guidelines and Standard Operating Procedures: Qualitative Study and Content Analysis.

BACKGROUND: Digitization is spreading exponentially in medical care, with improved availability of electronic devices. Guidelines and standard operating procedures (SOPs) form an important part of daily clinical routine, and adherence is associated with improved outcomes. OBJECTIVE: This study aimed to evaluate a digital solution for the maintenance and distribution of SOPs and guidelines in 2 different anesthesiology departments in Switzerland. METHODS: A content management system (CMS), WordPress, was set up in 2 tertiary-level hospitals within 1 year: the Department of Anesthesiology and Pain Medicine at the Kantonsspital Lucerne in Lucerne, Switzerland, as an open-access system, followed by a similar system for internal usage in the Department of Anaesthesiology and Pain Medicine of the Inselspital, Bern University Hospital, in Bern, Switzerland. We analyzed the requirements and implementation processes needed to successfully set up these systems, and we evaluated the systems' impact by analyzing content and usage. RESULTS: The systems' generated exportable metadata, such as traffic and content. Analysis of the exported metadata showed that the Lucerne website had 269 pages managed by 44 users, with 88,124 visits per month (worldwide access possible), and the Bern website had 341 pages managed by 35 users, with 1765 visits per month (access only possible from within the institution). Creation of an open-access system resulted in third-party interest in the published guidelines and SOPs. The implementation process can be performed over the course of 1 year and setup and maintenance costs are low. CONCLUSIONS: A CMS, such as WordPress, is a suitable solution for distributing and managing guidelines and SOPs. Content is easily accessible and is accessed frequently. Metadata from the system allow live monitoring of usage and suggest that the system be accepted and appreciated by the users. In the future, Web-based solutions could be an important tool to handle guidelines and SOPs, but further studies are needed to assess the effect of these systems.

[Measurement of attitudes toward interprofessional collaboration in an operating theatre - a cross-sectional study]. / Messung der Haltung zur interprofessionellen Zusammenarbeit in einer Operationsabteilung ­ eine Querschnittsstudie.

Measurement of attitudes toward interprofessional collaboration in an operating theatre - a cross-sectional study Abstract.Background: Interprofessional cooperation (IC) between healthcare professionals is essential for good treatment outcomes. Surgical departments place special demands on interprofessional cooperation (situational team formation, alterning work environment, coordinative overcrowding of work) within a health organisation. In order to achieve common goals in a team, it is important that those involved have a comparable understanding of and attitude towards interprofessional cooperation, regardless of their profession. Research Question: What is the internal consistency of the German version of the Jefferson Scale of Attitudes Toward Interprofessional Collaboration (JeffSATIC) when applied to personnel in an operating theatre? What is the attitude towards interprofessional cooperation between the various occupational groups in a surgical department of an acute care hospital functioning as a centre and a training establishment? Are there differences between the individual occupational groups and the sexes? Method: The validated JeffSATIC questionnaire was translated back into German and sent to 283 people in a surgical department with eleven operating theatres. The internal consistency of the questionnaire and differences in attitude towards interprofessional cooperation were examined. Findings: The German version of the JeffSATIC questionnaire is a reliable instrument for measuring the attitude of individuals towards interprofessional cooperation. It was used for the first time in the context of a surgical department. In the institution examined, there are no statistically significant differences between the different occupational groups and sexes in relation to the attitude to IC in the dimensions 'work relationship' and 'responsibility' determined by the questionnaire. The medical service anaesthesia shows the greatest divergence in attitude towards interprofessional cooperation within a professional group. Conclusions: In the institution examined, the prerequisites for successful interprofessional cooperation exist. In general, it should be further examined which factors influence the divergence in attitude per occupational group and whether these divergences in attitude are also associated with the quality of the actual cooperation.

How current transfusion practices in geriatric patients with hip fracture still differ from current guidelines and the effects on outcome: A retrospective observational study.

BACKGROUND: Transfusion guidelines have become increasingly restrictive. We investigated actual transfusion practices in geriatric hip fracture patients, why they differ from current guidelines and how this affects outcome. OBJECTIVES: The primary aim was to examine transfusion timing, evaluate how many red blood cell (RBC) transfusions are in keeping with guidelines and how this affects morbidity (infection, cardiac events and delirium), mortality and length of stay (LOS). Our secondary aim was to test the hypothesis that guidelines were more likely to be deviated from shortly before discharge and with consecutive transfusions. DESIGN: A retrospective observational study. SETTING: The Luzerner Kantonsspital, a major trauma centre, over a 12-month period from 1 February 2015 to 31 January 2016. PATIENTS: All patients over 70 years of age admitted to the Luzerner Kantonsspital with hip fractures over a 12-month period in 2015 to 2016 were included. RESULTS: 156 patients were included, to which 141 units of RBCs were transfused. All pre and intra-operative transfusions were according to guidelines; 110 transfusions were postoperative and 37 of these were not according to guidelines. Patients who were transfused had longer LOS in hospital (P = 0.002) and an odds ratio (OR) of 2.7 of contracting an infection (P = 0.04) in comparison with patients who were not transfused. No significant differences in mortality, LOS or morbidity were found between patients transfused according to guidelines and more liberal thresholds. Guidelines were more likely to be deviated from within the last 2 days before discharge than prior to this (58 vs. 24%, P = 0.03). Furthermore, 24 stable patients received two consecutive RBC units resulting in posttransfusion haemoglobin values of between 83 and 124 g l. CONCLUSION: Most RBC transfusions occur postoperatively, many still according to liberal transfusion thresholds, in particular shortly before discharge and as part of consecutive transfusions. Transfused patients had longer LOS and more infections than patients not transfused, but there was no difference in mortality, LOS or morbidity between patients transfused according to current guidelines and those where guidelines were deviated from.

Tuning in C-nociceptors to reveal mechanisms in chronic neuropathic pain.

OBJECTIVE: Develop and validate a low-intensity sinusoidal electrical stimulation paradigm to preferentially activate C-fibers in human skin. METHODS: Sinusoidal transcutaneous stimulation (4Hz) was assessed psychophysically in healthy volunteers (n = 14) and neuropathic pain patients (n = 9). Pursuing laser Doppler imaging and single nociceptor recordings in vivo in humans (microneurography) and pigs confirmed the activation of "silent" C-nociceptors. Synchronized C-fiber compound action potentials were evoked in isolated human nerve fascicles in vitro. Live cell imaging of L4 dorsal root ganglia in anesthetized mice verified the recruitment of small-diameter neurons during transcutaneous 4-Hz stimulation of the hindpaw (0.4mA). RESULTS: Transcutaneous sinusoidal current (0.05-0.4mA, 4Hz) activated "polymodal" C-fibers (50% at ∼0.03mA) and "silent" nociceptors (50% at ∼0.04mA), intensities substantially lower than that required with transcutaneous 1-ms rectangular pulses ("polymodal" ∼3mA, "silent" ∼50mA). The stimulation induced delayed burning (nonpulsating) pain and a pronounced axon-reflex erythema, both indicative of C-nociceptor activation. Pain ratings to repetitive stimulation (1 minute, 4Hz) adapted in healthy volunteers by Numeric Rating Scale (NRS) -3 and nonpainful skin sites of neuropathic pain patients by NRS -0.5, whereas pain even increased in painful neuropathic skin by approximately NRS +2. INTERPRETATION: Sinusoidal electrical stimulation at 4Hz enables preferential activation of C-nociceptors in pig and human skin that accommodates during ongoing (1-minute) stimulation. Absence of such accommodation in neuropathic pain patients suggest axonal hyperexcitability that could be predictive of alterations in peripheral nociceptor encoding and offer a potential therapeutic entry point for topical analgesic treatment. Ann Neurol 2018;83:945-957.

Functional Characterization of At-Level Hypersensitivity in Patients With Spinal Cord Injury.

At-level and above-level hypersensitivity was assessed in patients with chronic complete thoracic spinal cord injury (SCI). Patients were classified using somatosensory mapping (brush, cold, pinprick) and assigned into 2 groups (ie, patients with at-level hypersensitivity [SCIHs, n = 8] and without at-level hypersensitivity [SCINHs, n = 7]). Gender and age-matched healthy subjects served as controls. Quantitative sensory testing (QST), electrically- and histamine-induced pain and itch, laser Doppler imaging, and laser-evoked potentials (LEP) were recorded at-level and above-level in SCI-patients. Six of 8 SCIHs, but 0 of 7 SCINHs patients suffered from neuropathic below-level pain. Clinical sensory mapping revealed spreading of hypersensitivity to more cranial areas (above-level) in 3 SCIHs. Cold pain threshold measures confirmed clinical hypersensitivity at-level in SCIHs. At-level and above-level hypersensitivity to electrical stimulation did not differ significantly between SCIHs and SCINHs. Mechanical allodynia, cold, and pin-prick hypersensitivity did not relate to impaired sensory function (QST), axon reflex flare, or LEPs. Clinically assessed at-level hypersensitivity was linked to below-level neuropathic pain, suggesting neuronal hyperexcitability contributes to the development of neuropathic pain. However, electrically evoked pain was not significantly different between SCI patients. Thus, SCI-induced enhanced excitability of nociceptive processing does not necessarily lead to neuropathic pain. QST and LEP revealed no crucial role of deafferentation for hypersensitivity development after SCI. PERSPECTIVE: At-level hypersensitivity after complete thoracic SCI is associated with neuropathic below-level pain if evoked by clinical sensory stimuli. QST, LEP, and electrically-induced axon reflex flare sizes did not indicate somatosensory deafferentation in SCIHs.

Ultrasound-guided carotid sheath block for carotid endarterectomy: a case series of the spread of injectate.

INTRODUCTION: We aimed to show the spread of local anesthetic following an ultrasound-guided, double-injection technique of a carotid sheath block before carotid endarterectomy. METHODS: The study included 15 patients scheduled for elective carotid endarterectomy. The carotid sheath block was performed after ultrasound-guided localization of the carotid bifurcation (level C4-C6) at the posterior border of the sternocleidomastoid muscle. A mix of 7.5 mL ropivacaine 0.75%, 7.5 mL prilocaine1% and 3 mL iopromidum was injected at the base of the carotid bifurcation. An additional 15 mL of the mixture was administered subcutaneously at the surgical incision line. Thirty minutes after the block, a computed tomography scan of the head, neck region and upper thorax was performed to reconstruct a 3-D distribution of the injectate. RESULTS: All patients achieved C2-C4 dermatomal sensory blockade. None required conversion to general anesthesia. The injectate spread ranged from the vertebral body of C1 to the vertebral body of T3. The mean volume of distribution was 97±13 mL, the craniocaudal spread 138±19 mm, dorsoventral 57±8 mm and coronal 53±8 mm. The mean carotid artery circumference contact was 252°±77, with four patients (27%) presenting with a ring formation (360°) around the carotid artery. CONCLUSIONS: Ultrasound-guided carotid sheath block provided an extensive spread of local anesthetic. A complete ring formation of local anesthetic around the artery does not seem necessary for a successful anesthesia. The resulting nerve blockade thus appears sufficient for surgery, with minor risks compared to blind methods.

[OR-management and self-improvement - a discrepancy?]. / OP-Management - OP-Management†/†effiziente Klinikführung und Weiterbildung - ein Widerspruch?

Today, operating room management is essential for a modern hospital. The strategic controls of this cost-intensive area and the ongoing cost pressure have necessitated management attention to this area. Economical, processual and quality data are well-known and established, although analysis of different health delivering organisations by benchmarking is still difficult. It remains still a severe task for the management of an OR and anaesthesia department. For these fields data is needed to identify and measure the performance of these departments in the dimensions of finances, development, processes and patient's needs. The key performance indicators are exemplified for an anaesthesia department and discussed.

Intrathecal morphine analgesia after cervical and thoracic spinal cord tumor surgery.

OBJECT: The aim of this study was to provide evidence for the effect of intrathecal morphine application after spinal cord tumor resection. METHODS: Twenty patients participated in a prospective open proof-of-concept study. During dural closure, morphine (7 µg/kg) was injected into the subarachnoid space. All patients were monitored in an intensive care setting postoperatively. Pain, additional opioids given, and vital parameters were recorded. RESULTS: Six patients received a mean morphine dose of 365 µg between C-3 and C-7 and 14 patients received a mean dose of 436 µg between T-2 and T-12. In the cervical and thoracic groups, the mean Numeric Rating Scale score was highest upon intensive care unit admission (1.2 and 2.5, respectively) and declined at 12 hours (0.5 and 0.8, respectively). Minimal extra morphine was required. Minor side effects occurred without consequence. CONCLUSIONS: Intrathecal morphine for postoperative analgesia after resection of cervical and thoracic spinal cord tumors is effective and safe. These preliminary results require confirmation by larger comparative studies and further clinical experience.

PAIN OUT: an international acute pain registry supporting clinicians in decision making and in quality improvement activities.

RATIONALE, AIMS AND OBJECTIVES: Management of post-operative pain is unsatisfactory worldwide. An estimated 240 million patients undergo surgery each year. Forty to 60% of these patients report clinically significant pain. Discrepancy exists between availability of evidence-based medicine (EBM)-derived knowledge about management of perioperative pain and increased implementation of related practices versus lack of improvement in patient-reported outcomes (PROs). We aimed to assist health care providers to optimize perioperative pain management by developing and validating a medical registry that measures variability in care, identifies best pain management practices and assists clinicians in decision making. METHODS: PAIN OUT was established from 2009 to 2012 with funding from the European Commission. It now continues as a self-sustaining, not-for-profit project, targeting health care professionals caring for patients undergoing surgery. RESULTS: The growing registry includes data from 40 898 patients, 60 hospitals and 17 countries. Collaborators upload data (demographics, clinical, PROs) from patients undergoing surgery in their hospital/ward into an Internet-based portal. Two modules make use of the data: (1) online, immediate feedback and benchmarking compares PROs across sites while offline analysis permits in-depth analysis; and (2) the case-based clinical decision support system offers practice-based treatment recommendations for individual patients; it is available now as a prototype. The Electronic Knowledge Library provides succinct summaries on perioperative pain management, supporting knowledge transfer and application of EBM. CONCLUSION: PAIN OUT, a large, growing international registry, allows use of 'real-life' data related to management of perioperative pain. Ultimately, comparative analysis through audit, feedback and benchmarking will improve quality of care.

[Case report - a dangerous intoxication after ingestion of alkyl nitrite ("poppers")]. / Kasuistik - Schwere Intoxikation nach oraler Einnahme von Alkylnitrit ("Poppers").

This case report describes the inadvertent poisoning of a young man with "poppers" after having ingested an unknown amout of the drug. "Poppers" (alkyl nitrite) were made famous in the 1960s as a party drug, and during certain sexual practices, and are still in use today. The drug's inhalation leads to a short-lived rush, vasodilation and relaxtion of smooth muscles. An accidental ingestion can lead to a significant build-up of methemoglobin with dire consequences. The therapy consists of the intravenous administration of methylene blue.

Patients' perception of postoperative pain management: validation of the International Pain Outcomes (IPO) questionnaire.

UNLABELLED: PAIN OUT is a European Commission-funded project aiming at improving postoperative pain management. It combines a registry that can be useful for quality improvement and research using treatment and patient-reported outcome measures. The core of the project is a patient questionnaire-the International Pain Outcomes questionnaire-that comprises key patient-level outcomes of postoperative pain management, including pain intensity, physical and emotional functional interference, side effects, and perceptions of care. Its psychometric quality after translation and adaptation to European patients is the subject of this validation study. The questionnaire was administered to 9,727 patients in 10 languages in 8 European countries and Israel. Construct validity was assessed using factor analysis. Discriminant validity assessment used Mann-Whitney U tests to detect mean group differences between 2 surgical disciplines. Internal consistency reliability was calculated as Cronbach's alpha. Factor analysis resulted in a 3-factor structure explaining 53.6% of variance. Cronbach's alpha at overall scale level was high (.86), and for the 3 subscales was low, moderate, or high (range, .53-.89). Significant mean group differences between general and orthopedic surgery patients confirmed discriminant validity. The psychometric quality of the International Pain Outcomes questionnaire can be regarded as satisfactory. PERSPECTIVE: The International Pain Outcomes questionnaire provides an instrument for postoperative pain assessment and improvement of quality of care, which demonstrated good psychometric quality when translated into a variety of languages in a large European and Israeli patient population. This measure provides the basis for the first comprehensive postoperative pain registry in Europe and other countries.

Mechano-insensitive nociceptors are sufficient to induce histamine-induced itch.

The nerve fibres underlying histamine-induced itch have not been fully elucidated. We blocked the lateral femoral cutaneous nerve and mapped the skin area unresponsive to mechanical stimulation, but still sensitive to electrically induced pain. Nerve block induced significantly larger anaesthetic areas to mechanical (100 mN pin-prick, 402 ± 61 cm²; brush, 393 ± 63 cm²) and heat pain stimuli (401 ± 53 cm²) compared with electrical stimulation (352 ± 62 cm², p < 0.05), whereas the anaesthetic area tested with 260 mN (374 ± 57 cm²) did not differ significantly. Histamine was applied by iontophoresis (7.5 mC) at skin sites in which mechanical sensitivity was blocked, but electrical stimulation was still perceived 30 min after the nerve block (n = 9). In these areas iontophoresis of histamine provoked itching in 8/9 subjects with a mean maximum of 4.6 ± 1 (on an 11-point rating scale). Histamine-induced itch can thus be perceived at skin sites where input from mechano-sensitive polymodal nociceptors is blocked. In conclusion, input from mechano-insensitive nociceptors is sufficient to generate histamine-induced itch.

Positioning injury, rhabdomyolysis, and serum creatine kinase-concentration course in patients undergoing robot-assisted radical prostatectomy and extended pelvic lymph node dissection.

BACKGROUND AND PURPOSE: During robot-assisted radical prostatectomy (RARP), patients remain in a steep Trendelenburg position. This can cause positioning injuries as well as rhabdomyolysis. The primary diagnostic indicator of rhabdomyolysis is elevated serum creatine kinase (CK). We investigate whether RARP with extended pelvic lymph node dissection (ePLND) in a prolonged extreme Trendelenburg position can cause positioning injuries and rhabdomyolysis. PATIENTS AND METHODS: We performed a prospective study of the first 60 patients undergoing RARP and ePLND for organ-confined prostate cancer at our institute. Positioning injuries were graded according to three degrees of clinical severity. Serum-CK, serum-pH, and base excess (BE) were measured before, during, and for 5 days after surgery. Rhabdomyolysis was defined by serum-CK levels >5000 IU/L. RESULTS: Median operative time was 317 minutes (range 200-475 min); median time in the Trendelenburg position was 282 minutes (range 170-470 min). Serum-CK was significantly elevated 6 hours postoperatively, peaking at 18 hours postoperatively. Serum-CK levels did not correlate with pH, BE, and perioperative creatinine values. Serum-CK course shows weak correlation with body mass index (BMI), operative time, Trendelenburg position time, and medium correlation with positioning injuries of any degree. Twenty-one of the 60 (35%) patients showed positioning-related injuries: 16 (27%) patients degree I, 2 (3%) patients degree II, and 3 (5%) patients degree III. Rhabdomyolysis developed in 10 patients. Postoperative renal failure did not develop in any patient receiving postoperative hypervolemic diuretic therapy nor any patient with injuries degrees I, II, or III. conclusion: Clinically relevant positioning injuries and rhabdomyolysis can occur in patients who are subjected to prolonged extreme Trendelenburg position during RARP and ePLND, especially at the beginning of the learning curve. Serum-CK increases significantly after surgery, peaking 18 hours postoperatively. Serum-CK elevation alone is not predictive of positioning injury. By very long operative and Trendelenburg times as well as high BMI with visible position injuries, we recommend serum-CK measurement 6 and 18 hours postoperatively followed by hypervolemic therapy to prevent possible renal injury from rhabdomyolysis if serum-CK >5000 IU/L.

Telemedicine in the management of diving accidents: correlation of phone-assessed symptom severity with clinical findings.

INTRODUCTION: The object of this study was to evaluate to what extend the severity of decompression illness (DCI) assessed by a diving medicine specialist over the phone correlates with actual clinical findings. METHODS: The phone protocols of calls received by a diving medical hotline between January 2008 and December 2009 were analysed. Each case was followed up after completion of the treatment and categorized into one out of four severity groups according to the same standard protocol used for categorisation at the time of the initial hotline call. RESULTS: In 47 of 151 calls, DCI was suspected by the hotline experts. The initial estimation was coherent with the clinical findings in 37 cases, 9 were overestimated and one was underestimated. With the 95% bootstrap confidence interval 0.551 to 0.864 and computed weighted Cohen's κ coefficient = 0,721, the coherence between hotline assessment and clinical assessment can be considered as good. The five divers with minimal symptoms who were categorised as "no DCI possible" could not be followed up. CONCLUSION: We conclude that, despite some limitations to the study, particularly the limited sample size, a reliable assessment of the severity of DCI can be provided by a specialist-based telephone hotline.

Tensile strength decreases and perfusion pressure of 3-holed polyamide epidural catheters increases in long-term epidural infusion.

BACKGROUND AND OBJECTIVES: Epidural analgesia is an established method for pain management. The failure rate is 8% to 12% due to technical difficulties (catheter dislocation and/or disconnection; partial or total catheter occlusion) and management. The mechanical properties of the catheters, like tensile strength and flow rate, may also be affected by the analgesic solution and/or the tissue environment. METHOD: We investigated the tensile strength and perfusion pressure of new (n=20), perioperatively (n=30), and postoperatively (n=73) used epidural catheters (20-gauge, polyamide, closed tip, 3 side holes; Perifix [B. Braun]). To prevent dislocation, epidural catheters were taped (n=5) or fixed by suture (n=68) to the skin. After removal, mechanical properties were assessed by a tensile-testing machine (INSTRON 4500), and perfusion pressure was measured at flow rates of 10, 20, and 40 mL/h. RESULTS: All catheters demonstrated a 2-step force transmission. Initially, a minimal increase of length could be observed at 15 N followed by an elongation of several cm at additional forces (7 N). Breakage occurred in the control group at 23.5±1.5 N compared with 22.4±1.6 N in perioperative and 22.4±1.7 N in postoperative catheters (P<0.05). Duration of catheter use had no effect on tensile strength, whereas perfusion pressure at clinically used flow rates (10 mL/h) increased significantly from 19±1.3 to 44±72 mm Hg during long-term (≥7 days) epidural analgesia (P<0.05, analysis of variance). Fixation by suture had no influence on tensile strength or perfusion pressure. CONCLUSIONS: Epidural catheter use significantly increases the perfusion pressure and decreases the tensile strength.

[Co-analgesics--today and tomorrow--a receptor-based overview of therapeutical options]. / Co-Analgetika--heute und morgen--Eine rezeptorbasierte Ubersicht analgetischer Therapieoptionen.

The sensation of pain arises through stimulation of peripheral nociceptors and is transmitted centrally involving several receptors and ion channels. In addition many endogenous physiologic pain-modulating mechanisms exist. Besides of classical analgesics, numerous other drugs showed analgesic properties based on diverse modes of actions along the pain pathway. These co-analgesics, administered in combination with classical drugs, are able to reduce painful states of different origin. We describe the peripheral action sites of co-analgesics, such as cannabinoids, capsaicin, bisphosphonates, steroids and somatostatin. We also summarise the effect of peripherally and centrally acting ion-channel blockers, e.g. local anaesthetics, carbamazepine and tolperisone working on sodium channels and gabapentin and pregabalin working on calcium channels. Finally, central analgesic mechanisms are discussed, for instance the inhibition of NMDA-receptors by ketamine or magnesium, the stimulation of alpha2-receptors by clonidine, tizanidine or antidepressants, the activation of GABA-receptors through baclofen and other analgesic mechanisms of i.e. ondansetron and neostigmine.