[Structure of pain management facilities in Germany : Classification of medical and psychological pain treatment services-Consensus of the Joint Commission of the Professional Societies and Organizations for Quality in Pain Medicine]. / Struktur der schmerzmedizinischen Versorgung in Deutschland : Klassifikation schmerzmedizinischer Einrichtungen - Konsens der Gemeinsamen Kommission der Fachgesellschaften und Verbände für Qualität in der Schmerzmedizin.

On behalf of the Medical/Psychological Pain Associations, Pain Patients Alliance and the Professional Association of Pain Physicians and Psychologists, the Joint Commission of Professional Societies and Organizations for Quality in Pain Medicine, working in close collaboration with the respective presidents, has developed verifiable structural and process-related criteria for the classification of medical and psychological pain treatment facilities in Germany. Based on the established system of graded care in Germany and on existing qualifications, these criteria also argue for the introduction of a basic qualification in pain medicine. In addition to the first-ever comprehensive description of psychological pain facilities, the criteria presented can be used to classify five different levels of pain facilities, from basic pain management facilities, to specialized institutions, to the Centre for Interdisciplinary Pain Medicine. The recommendations offer binding and verifiable criteria for quality assurance in pain medicine and improved pain treatment.

Capsaicina al 8 por ciento para controlar el dolor neuropático periférico: una estrategia basada en casos clínicos / No disponible

La reunión multidisciplinar organizada por Astellas tuvo lugar en Milán el 28 de agosto de 2012. Alrededor de 150 médicos invitados, especializados en el dolor, procedentes de toda Europa y con conocimientos o experiencia en el uso de los parches de capsaicina al 8 % para tratar el dolor neuropático (DN) periférico, asistieron a la reunión para escuchar la presentación de distintos casos clínicos tratados con el parche de capsaicina al 8%, por parte de un grupo de ponentes europeos expertos en la clínica del dolor. El objetivo de la reunión era compartir experiencia clínica real sobre el uso del parche de capsaicina al 8% para controlar el DN siguiendo un formato interactivo y dando a los asistentes la oportunidad de intercambiar experiencia práctica directa con el uso de este medicamento. La reunión estuvo presidida por el Dr. Arun Bhaskar del Reino Unido. Este inauguró la reunión dando la bienvenida a los delegados, presentando a los ponentes, resumiendo los objetivos de la reunión y realizando una demostración del ThoughtSort, el software que por grupos a través de un iPad, hizo posible que todos los participantes de la sesión pudiesen interactuar. Los detalles de los casos clínicos que se presentaron en la reunión y que se resumen en este artículo responden a las opiniones personales de los ponentes (AU)

The Astellas peer-to-peer meeting took place in Milan on the evening of Tuesday 28 August, 18:00-20:00. Approximately 150 invited pain physicians from across Europe, all with some knowledge or experience of using the high-dose capsaicin patch to treat peripheral neuropathic pain (NP), attended the meeting to hear an expert European faculty of practising physicians present different case studies involving treatment with high-dose capsaicin. The objective of the meeting was to share real-world experience in the use of high-dose capsaicin for the management of NP in an interactive format to provide delegates with the opportunity to liaise with physicians who have direct, handson experience of high-dose capsaicin. Interactivity was a key component of the meeting and iPad technology was utilised to encourage discussions between the faculty and the delegates. The ThoughtSort application enabled both the faculty to ask delegates questions related to their case studies and the delegates to ask the faculty questions throughout their presentations. The meeting was chaired by Dr Arun Bhaskar from the UK. He opened the meeting by welcoming the delegates, introducing the faculty, outlining the objectives of the meeting and performing a demonstration of ThoughtSort. The delegates had to work in groups to answer questions via ThoughtSort, using one iPad between four and five delegates. Details of the case studies that were presented at the meeting and summarised within this report are the personal opinions of the faculty members (AU)

Laxative management in ambulatory cancer patients on opioid therapy: a prospective, open-label investigation of polyethylene glycol, sodium picosulphate and lactulose.

Constipation and the laxatives polyethylene glycol (PEG), sodium picosulphate (SPS) and lactulose (L) were investigated in outpatients with cancer and on opioid therapy. Randomly selected patients were enrolled in a prospective, controlled, open-label trial. Endpoints were number of patients taking laxatives >28 days, number of patients with a stool-free interval >72 h (sfi72), dosage, numerical rating scale (NRS) for constipation, and European Organization for Research and Treatment of Cancer (EORTC) Quality of Life (QoL) questionnaire scores. The 348 patients had comparable demographic and medical data. In this ambulatory population, mobility scores remained unaffected. Constipation incidence was 5.7%, with sfi72 42, mean NRS 2.3557 and mean QoL 2.1. A total of 53.2% discontinued their laxative medication. Laxative use correlated with higher opioid usage (morphine-equivalent mg/day: no laxative 98.2, SPS 128.2, PEG 139.9, L 154.5). PEG was the most frequently prescribed laxative (PEG 27.3%, SPS 10.3%, L 9.2%). PEG (sfi72 12.6%, NRS 2.2, QoL 2.1) and SPS (sfi72 11.1%, NRS 2.7, QoL 2.2) proved more effective than L (sfi72 15.5%, NRS 3.8, QoL 2.5). In spite of opioid therapy, the incidence of constipation was low in these ambulatory cancer pain patients at an early disease stage. For prevention of constipation, PEG or SPS is recommended instead of L.

[Modafinil for the treatment of cancer-related fatigue : an intervention study]. / Modafinil zur behandlung der tumorfatigue : eine interventionsstudie.

AIM: the authors conducted an open-label investigation examining the effects of modafinil in reducing fatigue in patients with cancer, undergoing cancer treatment, and receiving opioid therapy. METHODS: after approval by the local Ethics Committee and informed consent cancer patients who reported fatigue - defined as persistent tiredness interfering with usual functioning - were enrolled in the study. Once daily, patients received 100 mg open-label modafinil. The Fatigue Severity Scale (FSS), Epworth Sleepiness Scale (ESS), and a visual analogue scale (VAS, 0-10) were performed at baseline (t1), day 7 (t2), and day 28 (t3). Further assessment comprised the d2 Test of Attention (d2), the Hamilton Depression Scale (HAMD), the Eastern Cooperative Oncology Group-Score (ECOG), side effects, and patients' satisfaction with modafinil treatment. RESULTS: of the 37 patients who were enrolled, 29 completed all assessments in the study. Modafinil had a significant effect on the FSS (t1 44.6+/-12.2, t2 39+/-12.4, t3 35.3+/-13.8 (p=0.015), on the VAS (t1 6+/-3.1), t2 4.5+/-2.8, t3 3.7+/-2.8 (p=0.005), and an insignificant effect on d2 parameters of neurophysiological functioning and ESS. No differences were seen for ECOG and patients' satisfaction. No severe adverse effects were detected. CONCLUSION: modafinil improved alertness and cognitive skills in patients receiving cancer pain treatment by enhancing vigilance and cognitive performance. Although confirmation of this preliminary result is needed, these findings suggest that modafinil may improve quality of life in this patient population. However, in Germany the use of modafinil for fatigue is off-label and careful assessment of fatigue is needed prior to treatment. Randomized controlled trials are needed to confirm this evidence.

Patient assessment of a novel therapeutic approach for the treatment of severe, chronic pain.

BACKGROUND AND OBJECTIVES: Opioid-induced constipation can have a major negative impact on patients' quality of life. This randomised clinical trial evaluated patient assessment of the efficacy and tolerability of oral prolonged-release (PR) oxycodone when co-administered with oral naloxone PR. METHODS: Two hundred and two patients with chronic cancer- or non-cancer-related pain undergoing stable oxycodone PR therapy (40, 60 or 80 mg/day) were randomised to one of four intervention groups: 10, 20 or 40 mg/day naloxone PR or placebo. Following a 4-week maintenance phase, patients were followed-up for 2 weeks in which time they received oxycodone PR only. At the end of the maintenance phase, patients and investigators were asked to assess treatment efficacy and tolerability, as well as preference for the titration or maintenance phase. RESULTS: Patient and investigator global assessment of efficacy and tolerability improved with increasing naloxone dose. Efficacy was ranked as 'good' or 'very good' by 50.0%, 67.4% and 72.5% of patients in the 10, 20 and 40 mg naloxone PR dose groups, respectively, compared with 43.5% of patients in the placebo group. Patient assessment of tolerability was similar between treatment groups and placebo, being ranked as 'good' or 'very good' by 83.3%, 79.1% and 82.5% of patients in the 10, 20 and 40 mg/day naloxone PR dose groups, respectively, compared with 71.7% of patients in the placebo group. The maintenance treatment phase was preferred by patients in the naloxone groups. A 2 : 1 dose ratio of oxycodone to naloxone was also assessed. Efficacy was ranked as 'good' or 'very good' by 70.4% of patients treated with the 2 : 1 dose ratio compared with 43.5% of patients receiving placebo. Tolerability of the 2 : 1 dose ratio was ranked as being 'good' or 'very good' by 81.5% of patients compared with 71.1% for the placebo group and patients preferred the maintenance phase. CONCLUSIONS: The co-administration of oral naloxone PR with oxycodone PR improves patient assessment of analgesic opioid therapy for severe chronic pain, in terms of both efficacy and tolerability.

[Superior cervical ganglion: an anatomical variant. Are variations of the cranial carotid artery a risk factor for accidental intravascular injection?]. / Ganglion cervicale superius: eine anatomische Besonderheit. Variationen der A. carotis interna als Risiko einer akzidentellen intravasalen Injektion?

A variation of the cranial carotid artery is demonstrated in an anatomical specimen revealing possible complications of ganglionic local opioid analgesia at the superior cervical ganglion. Located in the area of the puncture site, a loop of the aberrant carotid artery adheres closely to the pharyngeal wall in the medial position, shortening the distance between the arterial lumen and the oral cavity to 5 mm. With an incidence of 25%, an aberrant carotid artery could possibly facilitate an accidental intravascular injection during ganglionic local opioid application at the superior cervical ganglion.

Less nausea, emesis, and constipation comparing hydromorphone and morphine? A prospective open-labeled investigation on cancer pain.

GOALS OF WORK: The purpose of this trial was to evaluate the effect of long-term treatment with either oral sustained-release hydromorphone (HM) or morphine (M) on nausea, emesis, and constipation. MATERIALS AND METHODS: In a prospective, open-labeled, controlled trial, 100 outpatients with cancer pain and treatment with HM or M were enrolled. Mobility, pain, and gastrointestinal symptoms were assessed by the ECOG performance status, selected items of the EORTC questionnaire and Numerical Rating Scales (NRS). Data were analyzed using descriptive and confirmatory statistics (paired t-test, chi square test, Poisson regression). MAIN RESULTS: Demographic and medical data were comparable in both treatment groups. Taking into account different conversion factors, opioid doses (M 94.4 mg/d vs. HM 137.6 [HM/M = 1:5], p = 0.05 and HM 206.4 [HM/M = 1:7.5], p = 0.0002, respectively) were higher under hydromorphone and NRS of pain (M 2.3 vs. HM 3.6, p = 0.0002) lower under morphine. Nausea and emesis did not attenuate in 33% of patients. NRS of nausea (M 2.5 vs. HM 1.5; p = 0.01), incidences of emesis (M 0.7/d vs. HM 0.1/d, p = 0.0001), the consumption of antiemetics (M 26 vs. HM 14, p = 0.01), and the number of constipated patients (M 8 vs. HM 2, p = 0.04) were higher in the morphine group. An extended use of substances for symptom control revealed constipating effects (M 31 vs. HM 13, p = 0.0003) and was associated with a higher incidence of constipation in the morphine group. CONCLUSIONS: Symptom control in outpatients with cancer pain may be complicated by a symptom controlling medication. Particularly, antiemetics revealed potentially constipating effects. Despite lower opioid doses, morphine provided a better pain control but produced more side effects. Comparing hydromorphone with morphine, it remains unclear if fewer incidences of constipation and nausea in the hydromorphone group were related to pharmacodynamic effects or to a less effective pain control with significantly higher NRS for pain. However, the conversion factor of oral hydromorphone and morphine needs to be questioned.

The effects of morphine on human 5-HT3A receptors.

5-HT3 receptors are ligand-gated ion channels that are involved in the modulation of emesis and pain. In this study, we investigated whether the opioid analgesic, morphine, exerts specific effects on human 5-HT3 receptors. Whole-cell patches from HEK-293 cells stably transfected with the human 5-HT3A receptor cDNA were used to determine the effects of morphine on the 5-HT-induced currents using the patch clamp technique. At negative membrane potentials, 5-HT induced inward currents in a concentration-dependent manner. The 5-HT3 receptor antagonist, ondansetron, (0.3 nM) reversibly inhibited the 5-HT-induced signals. Morphine reversibly suppressed 5-HT-induced peak currents as a function of concentration (IC50 = 1.1 microM, Hill coefficient = 1.2). The block by morphine decreased with increasing 5-HT concentrations, suggesting a competitive effect. In addition, the activation, as well as the inactivation, kinetics of the currents were significantly slowed in the presence of morphine. The morphine antagonist, naloxone, also inhibited 5-HT-induced currents (e.g., at 3 microM by 17%). The effects of morphine and naloxone were not additive. The potency of morphine and the competitivity of the blocking effect points to a specific mechanism at a receptor site rather than an unspecific membrane effect.

[Managing patients with chronic orofacial pain in the outpatient departments of dental and maxillofacial surgeons. Results of a survey]. / Versorgung von Patienten mit chronischem orofazialem Schmerz. Ergebnisse einer Befragung in ambulanten zahnärztlichen und Mund-Kiefer-Gesichts-Chirurgie-Einrichtungen.

OBJECTIVE: The aim of this study was to evaluate the significance attributed by dental and maxillofacial surgeons to the ambulatory management of chronic orofacial pain syndromes. MATERIALS AND METHODS: All the dentists and oral and maxillofacial surgeons working in ambulatory capacities within a county of the German Rhine Area were asked to answer a questionnaire on demographic data, diagnostic and therapeutic principles, and the use of analogue scales, surgical, minimal-invasive or pharmacological procedures. RESULTS AND DISCUSSION: Seventy-two ambulatory institutions reported 985 patients suffering from temporomandibular disorders (40.2%), headache-syndromes associated with facial pain (18.2%), and atypical odontalgia respectively phantom tooth pain (17.0%). Patients were characterized by prior dental treatment or trauma (41.9%), female gender (66.8%), middle age (81.1%, 20-60 years), very frequent change of therapists (54.6%) and long-term perseverance of pain (61.1% >6 months). Only 7% of therapists used visual or numerical analogue scales to assess pain intensity. Therapeutic procedures consisted of analgesics (15.7%) and further surgical procedures (47.7%). Pain therapists were rarely involved (12.5%). CONCLUSION: Dental and maxillofacial surgeons should apply an interdisciplinary and multimodal approach to diagnostics and therapy at an earlier stage in order to optimize the pain management of patients with chronic orofacial pain.

Influence of fentanyl, alfentanil, and sufentanil on motor evoked potentials.

The effects of the opioids fentanyl, alfentanil, and sufentanil on motor pathways were studied in a total of 30 rabbits. Compound muscle action potentials (CMAP) were recorded from the extensor muscles of the upper extremity as well as evoked spinal cord potentials (ESCP) from the thoracic epidural space in response to electrical stimulation of the motor cortex. After establishing stable baseline values, an equipotent intravenous bolus of one of the three opioids was applied that abolished reflex motor response to noxious stimulation. Motor evoked potentials (MEP) were recorded from the time of bolus administration until recovery of MEP amplitudes and latencies. Afterwards, the opioids were administered continuously with cumulative dosage up to total absence of motor evoked response. Our results show a dose-dependent suppression of the CMAP: When reflex movement to noxious stimulation was extinguished, we found a significant (P < .001) reduction of the amplitudes to 34+/-18% (mean +/- SD) in the fentanyl group, to 43+/-24% in the alfentanil group, and to 53+/-20% of baseline values in the sufentanil group. Increasing opioid plasma levels were associated with complete extinction of the CMAP. We hypothesize that the descending volleys within motor pathways are mainly inhibited at a spinal level, because ESCP, particularly the number of spinal I-waves, are not severely affected even when CMAP are completely suppressed. In conclusion, intraoperative monitoring of descending pathways by means of MEP during anesthesia with opioids is feasible at anesthetic plasma concentrations maintaining a surgical level of analgesia. Even with high opioid plasma levels, a valid MEP monitoring could be performed evaluating neural activity of spinal MEP.

Isoflurane plus nitrous oxide versus propofol for recording of motor evoked potentials after high frequency repetitive electrical stimulation.

The goal of this study was to test the influence of two widespread techniques of general anesthesia on motor evoked potentials (MEP) in response to transcranial and direct cortical high frequency repetitive electrical stimulation. Total intravenous anesthesia (TIVA) based on propofol and alfentanil was examined in 17 patients (group A), and balanced anesthesia (BA), based on nitrous oxide, isoflurane and fentanyl, was studied in 13 patients (group B). Distinct motor responses were available in 15 of 17 patients (88%) of group A, and in one of 13 patients (8%) of group B. Amplitudes increased significantly with increasing stimulus intensity and number of pulses under conditions of TIVA. At the same time, latencies decreased significantly with increasing stimulus intensity and decreasing interstimulus interval, but not with increasing number of pulses. It is hypothesized that propofol suppresses corticospinal I-waves at the cortical level, resulting in a conduction block at the level of the alpha-motoneuron, and that this effect may be overcome by high frequency repetitive stimulation. In contrast, nitrous oxide and isoflurane seem to have an additional suppressive effect on corticospinal D-waves, which may be overcome by higher stimulation intensity. In conclusion, transcranial high frequency repetitive stimulation and TIVA provide a feasible setting for intraoperative MEP monitoring, while higher doses of nitrous oxide and isoflurane are not compatible with recording of muscular activity elicited by the stimulation technique as described.

Influence of nitrous oxide on motor-evoked potentials.

STUDY DESIGN: Rabbits were used as an experimental model in the study of motor-evoked potentials. OBJECTIVES: To evaluate the effect of nitrous oxide on motor-evoked potentials while monitoring direct muscle and spinal cord responses. SUMMARY OF BACKGROUND DATA: Motor-evoked potential monitoring provides a promising tool for intraoperative assessment of descending pathways function. However, to date, this technique is still at an experimental stage, since its routine use is mainly limited because of intraoperative recording difficulties caused by the influence of anesthesia. METHODS: Eight male rabbits weighing between 3000 g and 3500 g were studied. Motor-evoked potentials were recorded from the extremity muscles and from the epidural space of the thoracic cord in response to electrical stimulation of the motor cortex at baseline conditions and at increasing nitrous oxide concentrations (10-70 vol%). RESULTS: The authors found a major suppressive effect of high nitrous oxide concentrations on the electromyographic responses. With 50 vol% nitrous oxide, electromyographic amplitudes were suppressed to 46% (fore leg) and 14% (hind leg) of the baseline values, whereas latencies did not change significantly. In contrast to muscular activity, spinal evoked responses representing neural activity were not affected by any concentration of nitrous oxide. CONCLUSIONS: Intraoperative monitoring of descending pathways by means of motor-evoked potentials during anesthesia of the rabbits based on nitrous oxide is feasible when neural activity is evaluated. Higher doses of nitrous oxide, however, are not compatible with recording of muscular activity.

Transcranial high-frequency repetitive electrical stimulation for recording myogenic motor evoked potentials with the patient under general anesthesia.

OBJECTIVE: To demonstrate the feasibility of transcranial high-frequency electrical stimulation with the patient under general anesthesia with propofol and alfentanil. This method may be a useful tool for intraoperative monitoring of the motor pathways during cerebral and spinal operations. METHODS: A short train from one to eight monopolar anodal electrical pulses was applied transcranially to the motor cortex with a frequency from 100 to 500 Hz in 10 patients. Myogenic motor evoked potentials (MEPs) were recorded from forearm flexor muscles, thenar, and hypothenar. Amplitude and latency of MEPs were evaluated after different stimulation parameters. This combination of anesthetic and transcranial stimulation technique allows recording of myogenic MEPs during general anesthesia, which was found not to be possible with single pulse transcranial stimulation. RESULTS: To elicit myogenic MEPs from the target muscles, stimulation had to be applied within the following parameters: minimum threshold intensity was 60 mA for forearm flexor and thenar and 80 mA for hypothenar; minimum number of pulses was two for forearm flexor muscles and thenar and three for hypothenar; minimum stimulation frequency was 200 Hz for thenar and hypothenar and 100 Hz for forearm flexor muscles. CONCLUSION: Transcranial high-frequency repetitive electrical stimulation seems to be a new method for monitoring the motor tract. With this method, it is possible to monitor the motor function without interfering with the surgical team or with the surgical treatment of infratentorial and spinal lesions. Monitoring of relaxation is necessary to compare the amplitude of MEPs.

[Effect of premedication and barbiturate hypnotics on motor evoked potentials induced by magnetic cortex stimulation]. / Einfluss von Prämedikation und Barbiturathypnotika auf motorisch evozierte Potentiale mittels magnetischer Kortexstimulation.

OBJECTIVE: The aim of this study was to investigate the influence of the premedication and the influence of the two barbiturates methohexital and thiopental on magnetically evoked compound muscle action potentials (magnet MEP) in humans. METHODS: 40 Patients (ASA-PS I-II) undergoing lumbar nucleotomy were included in this study after obtaining written informed consent. The study was approved by the local ethical committee. All patients were premedicated with 0.5 mg atropine, 25 mg promethazine and 50 mg pethidine. For induction of anaesthesia patients randomly received methohexital or thiopental by continuous infusion with increasing infusion rates every 15 seconds up to a minimal anaesthesia level in 15 minutes. Transcranial magnetic stimulation was delivered by the magstim 200 magnetic stimulator. Magnetic MEPs were recorded from the surface of the short abductor pollices muscle. MEP-examination was performed preoperatively, after premedication and every two minutes during the induction of anaesthesia. Every other two minutes the patients level of consciousness were assessed and documented. Statistical calculations were performed with the U-test. RESULTS: No statistical differences were found for the mean induction time in the two groups. No statistical difference in amplitude and latency could be observed between the preoperative values and the values measured after premedication. During anaesthesia induction the amplitude decreased in both groups. In 25 of the 40 cases, the MEP disappeared completely before the patients fell asleep. The thiopental group showed a significantly lower incidence of MEP preservation (20%) compared to methohexital (50%). CONCLUSIONS: Premedication with atropine, promethazine and pethidine has no influence on magnetic MEP. Methohexital allows the highest incidence of successful MEP recordings with sufficient anaesthesia. A success rate of only 50% even in cases without motorpathway affection makes the application of magnetic MEP an unreliable tool for intraoperative monitoring.

The safe use of anaesthetics and muscle relaxants in older surgical patients.

Age greater than or equal to 75 years is not a special risk for adverse outcomes after general anaesthesia on its own but an indicator of risk. Biological or physiological age expressed by preoperative health status is much more important than chronological age. The type of anaesthesia seems to play no, or only a minor role. It is, however, most important to reduce the dosage considerably. As a rule of thumb, the dosage should be reduced by 10 to 15% for every decade over the age of 40. In addition, patients must be monitored extensively intra- and postoperatively, ideally in an intensive care setting. The controversy concerning regional versus general anaesthesia should be studied further. Regional anaesthesia techniques like high spinal or epidural anaesthesia that are haemodynamically effective do not reduce morbidity and mortality postoperatively but have the risk of profound hypertension. Peripheral blockades and spinal or epidural anaesthesia without additional sedation may, however, be associated with a reduced incidence of complications. The reduced reserves of geriatric patients demand for experienced anaesthetists and surgeons as well as intense intra- and postoperative monitoring. To secure a short recovery period, we recommend administration of short-acting drugs like propofol, midazolam, alfentanil, vecuronium, atracurium or isoflurane in appropriately reduced dosages.

Effects of four intravenous anesthetic agents on motor evoked potentials elicited by magnetic transcranial stimulation.

The influence of four intravenous anesthetic agents on motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (magnetic MEP) was examined in 77 subjects. The patients were anesthetized by a continuous intravenous infusion of one of the following anesthetic agents: propofol, etomidate, methohexital, or thiopental. Comparable anesthetic effects among the four agents were achieved by computing an infusion scheme for each drug. Infusion rates were increased slowly in a step-wise manner in order to reach minimal anesthetic blood concentrations within 15 minutes. During anesthesia induction, magnetic MEPs were recorded every 2 minutes from the abductor pollicis brevis muscle. The patient's level of consciousness was assessed and documented in the alternating minutes. A dose-related reduction of the MEP amplitudes was seen in all drug groups, while the latencies remained constant. Reduction of the amplitude was occasionally so prominent that the MEP was completely abolished before adequate anesthesia was achieved. MEPs were obtainable at the end of anesthesia induction in 14% of the propofol group (n = 22), 57% of the etomidate group (n = 21), 53% of the methohexital group (n = 19), and 20% of the thiopental group (n = 15). Propofol and thiopental showed significantly stronger suppression of MEP, when compared to etomidate (both P < 0.01) and to methohexital (P = 0.01 and 0.05, respectively). Etomidate was the least detrimental anesthetic agent for intraoperative monitoring of magnetic MEP. Nonetheless, the low incidence of 57% of preserved MEP in subjects without motor deficits indicated the inadequacy of this technique for intraoperative monitoring. More effective transcranial stimulation techniques are required for successful intraoperative MEP monitoring.

[Muscle relaxation with no effect on oxygen uptake during isoflurane anesthesia?]. / Muskelrelaxierung ohne Effekt auf die O2-Aufnahme bei Isofluran-Anästhesie?

To determine the effects of vecuronium neuromuscular blockade on O2 consumption (VO2) during isoflurane anaesthesia 12 patients were studied. 12 patients (ASA-PS I-II, 37.1 +/- 12.1 yr, 173 +/- 8 cm, 70.1 +/- 8.6 kg), scheduled for urological lower abdominal surgery, received isoflurane-N2O-O2-anaesthesia under steady-state conditions (1.3 MAC). Duration of anaesthesia was 169 +/- 32 min and 0.057 +/- 0.016 mg/kg/h vecuronium were needed. The desired level of neuromuscular transmission was set to 10% of control. This level of neuromuscular blockade was kept constant for 60 min by a negative feedback controlled infusion of vecuronium. VO2 was measured by an indirect calorimetry device (MMC Horizon, STPD). During and after recovery of neuromuscular function anaesthesia was maintained and oxygen measurements were continued. Preanaesthetic values of VO2 were in the predicted range for basal metabolism. Steady-state general anaesthesia lead to an 26-28% reduction of VO2 (Range: 144-232 ml/min) compared to the preanaesthetic values (202-288 ml/min, p < 0.01). Neuromuscular blockade showed no significant effect on O2 uptake. We conclude that in patients with adequate depth of anaesthesia vecuronium-induced neuromuscular blockade does not lead to a further reduction of oxygen consumption, since muscular tone is already reduced by general anaesthesia.

Total intravenous anesthesia for improvement of intraoperative monitoring of somatosensory evoked potentials during aneurysm surgery.

Two anesthetic regimens for monitoring somatosensory evoked potentials (SEPs) during intracranial aneurysm surgery were compared. Eighty-four sequential cases of intracranial aneurysms were operated on employing SEP monitoring. The first group of 22 cases was anesthetized with "balanced anesthesia" and the second group of 62 cases received total intravenous anesthesia (TIVA) consisting of propofol and alfentanil. In the TIVA group, the amplitude of early cortical SEP responses (N20-P25, or P40-N50) was significantly higher than that of responses in the balanced anesthesia group. In median nerve SEPs, the averaged amplitude of N20-P25 was 3.22 microV with TIVA and 1.69 microV with balanced anesthesia (P = 0.006). Similarly, posterior tibial nerve SEPs showed a P40-N50 response of 1.85 microV and 1.00 microV, respectively (P = 0.017). The superior signal-to-noise ratio obtained with TIVA allowed more frequent and reliable intraoperative SEP recordings than was possible with balanced anesthesia, resulting in rapid and reliable feedback for the surgeon. In 19% of median nerve SEPs recorded with TIVA, the cortical responses were over 5 microV in amplitude, so that reproducible N20-P25 responses were obtainable by averaging only 10 to 50 serial responses, that is, two to three recordings per minute. The higher amplitude of posterior tibial nerve SEPs recorded with TIVA made monitoring during surgery for anterior communicating artery aneurysms possible in all cases. This was not always the case with balanced anesthesia. The late deflection of median nerve SEPs (N30) was more frequently observed with TIVA.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of the epileptic focus during methohexital-induced anesthesia.

A short anesthesia was provided by methohexital for painless percutaneous removal of subdural electrodes in 27 patients with medically intractable, complex partial seizures who had undergone invasive preoperative evaluation. Electrocorticographic(ECoG) recordings performed before and during the narcosis were submitted to visual (n = 27) and computerized (n = 3) analysis to obtain additional information about the location of the epileptic focus (or foci). The following observations were made: focal epileptiform potentials were induced in 24 of 27 patients (89%); (b) in 20 of these 24, the induced spikes appeared amid or were followed by isoelectric or subdelta activity. These spikes were characterized by high amplitude as well as rhythmic and synchronized appearance over a circumscribed focal area (or areas) known to be spontaneously epileptogenic. This phenomenon, termed spike-burst-suppression (SBS) pattern, allowed identification of the primary epileptic focus in many patients with temporal lobe epilepsy. Furthermore, it indicated a good outcome of epilepsy surgery. Computerized analysis of the induced synchronized spikes (n = 3) allowed further delineation of the primary site of epileptogenicity and quantitative comparison of multiple epileptic generators. ECoG recording during deep methohexital-induced narcosis is a valuable tool for lateralization and delineation of the primary epileptogenic focus.

[Total intravenous anesthesia using propofol and alfentanil as compared to combined inhalation anesthesia reduces the flow velocity in the middle cerebral artery. A Doppler sonographic study]. / Totale intravenöse Anaesthesie mit Propofol und Alfentanil verringert im Gegensatz zu einer kombinierten Inhalationsanaesthesie die Fliessgeschwindigkeit in der A. cerebri media. Eine Doppler-sonographische Untersuchung.

Anesthesia for craniotomies should guarantee hemodynamic stability, preservation of cerebral autoregulation, and rapid postoperative recovery of consciousness. Increases in intracranial pressure (ICP) and postoperative respiratory depression should be avoided. Combined anesthesia (KA) with N2O and volatile anesthetics may increase cerebral blood flow (CBF), ICP, and cerebral oxygen consumption. According to recent studies, total intravenous anesthesia (TIVA) with propofol and alfentanil seems to best fulfill the requirements. Using transcranial Doppler sonography (TCD) (TC2-64, EME), we studied the influence of TIVA and KA under normo- and hyperventilation on the blood flow velocity (BFV) and pulsatility of the middle cerebral artery (MCA). METHODS. Two groups of 10 patients each undergoing craniotomy were investigated. Systolic and mean BFV, pulsatility index, mean arterial blood pressure, heart rate, and arterial CO2 tension were measured at four time intervals: (1) preoperatively; (2) 15 min after anesthesia induction under normoventilation, preoperatively; (3) 25 min after anesthesia induction under hyperventilation, preoperatively; and (4) 6 h postoperatively. The patients were premedicated with flunitrazepam 1 mg PO. TIVA was induced with 60 mg propofol, 1 mg alfentanil, and 6 mg vecuronium; simultaneously infusions of propofol (15 mg/min) and alfentanil (0.3 mg/min) were started and were maintained until the dura was completely opened. The infusion rates were then reduced to 6 mg/min propofol until skin suturing and 0.1 mg/min alfentanil until dural suturing was completed. Patients were ventilated with O2/air (fiO2 = 0.5). In the KA group anesthesia was induced with 4-6 mg/kg thiopental, 0.15 mg fentanyl, and 6 mg vecuronium and maintained with boluses of fentanyl, N2O (fiO2 = 0.5), and isoflurane (1.3 MAC). The time course is illustrated in Figs. 1 and 2 and the results are shown in Tables 1 and 2. They were tested using a one-factor analysis of variance and the Kruskal-Wallis range test. RESULTS. There was a significant decrease in systolic and mean BFV combined with an increase in pulsatility index after induction of TIVA, while KA induction effected no significant change in cerebral hemodynamics. The subsequent hyperventilation caused a similar decrease in mean BFV and increase in pulsatility index in both groups. CONCLUSION. Using the assumption that the diameter of the MCA is nearly constant, the reduction in BFV associated with an increase in pulsatility during TIVA is explainable as a decrease in CBF. By having a comparable influence on hemodynamics, the reduction in CBF with increase in cerebral vascular resistance seems to make TIVA the more advantageous anesthesia technique for patients with reduced intracranial compliance.