[Burnout in anesthesiology and intensive care : is there a problem in Germany?]. / Burn-out in der Anästhesie und Intensivmedizin : Gibt es ein Problem in Deutschland?

BACKGROUND: With the demands faced by anesthetists and intensive care physicians apparently increasing continuously in Germany, the increased risk of burnout in comparison with the general working population is discussed. This debate has previously been merely speculative because of the lack of studies comparing the burn-out risk of the German working population with anesthetists. Accordingly it was not certain whether anesthetists really are at greater risk of developing burnout as has often been suggested. Moreover, age, gender, function, workplace environment, e.g. working at a hospital compared to a general practitioner (GP) surgery, may influence the risk of burnout. Therefore, this study examined whether the risk for anesthetists in Germany suffering from burnout really is greater than in other occupations. In addition, factors influencing the burnout risks of anesthetists were analyzed. METHOD: A total of 3,541 questionnaires completed by German aaesthetists for a study on work satisfaction by the CBI (Copenhagen Burnout Inventory, part of the Copenhagen Psychosocial Questionnaire, COPSOQ) were analyzed. Apart from calculating the number of participants with a high risk of developing burnout syndrome, the data were used to calculate a generalized burnout score for all participants. The score was compared with data from both a random sample representing a wide variety of occupations from among the general population in Germany (n = 4,709) and a random sample of German hospital doctors (n = 616). In addition, subgroups were formed by gender, function (senior consultant, senior physician, specialist, junior doctor) and type and place of work (university hospital, public hospital, private clinic, GP surgery, freelance work) and the proportion of each group with a high risk of burnout syndrome was calculated. In addition, general burnout scores were compared statistically for differences among the various groups. RESULTS: The proportion of study participants with a high risk of burnout was 40.1%. Differences were found to exist between genders (male 37.2% versus female 46%), qualifications (senior consultant 28.9%, senior physician 38%, specialist 41.5%, junior doctor 46.7%) and working in a hospital (41.3%) compared to a GP surgery (33.2%). The random sample of hospital doctors (n = 616) showed a burnout score of 49 ± 19 (mean ± standard deviation), compared to 44 ± 19 for a random sample of the German population (n = 4,709) and 42 ± 19 for anesthetists (p < 0.01). Of the subgroups formed, the highest score (49.1 ± 19) was recorded for female junior doctors working in anesthesia. The type of hospital did not influence the burnout score (university hospital 43.8 ± 19.8 versus public hospital 42.9 ± 19.1 versus private hospital 42.4 ± 18.7, p > 0.05). Working in a hospital was found to result in higher burnout scores than in a GP surgery or freelance work (43 ± 19.2 versus 38.1 ± 20.5; t(3531) = 5.0, p < 0.001) CONCLUSIONS: Despite 40.1% of anesthetists being at high risk of burnout, generally speaking the risk of burnout among anesthetists was not higher than in other occupational groups in Germany. However, burnout risks for specific groups, such as female junior doctors in anesthesia, were higher and the possibility of providing social support in the workplace should be considered.

[Anaesthesia for combined pancreatic and renal transplantation in a patient with mitochondrial encepahalomyopathy--a case report]. / Anästhesieführung zur kombinierten Pankreas- und Nierentransplantation bei einer Patientin mit Mitochondriopathie--Ein Fallbericht.

Mitochondrial disorders encompass a group of syndromes produced by genetic defects that disrupt mitochondrial energy production. The impaired mitochondrial energy supply affects nearly all organs and tissues leading to a variable clinical presentation. The possible multisystem involvement complicates the management of anaesthesia and perioperative care. Exact knowledge of the path physiology of mitochondrial diseases may help to avoid perioperative anaesthesiological complications. This report describes the anaesthetic management of a patient with a mitochondrial disorder during combined pancreatic and renal transplantation, and discusses some of the anaesthetic implications of mitochondrial diseases. Due to the potential susceptibility of patients with mitochondrial diseases to malignant hyperthermia, anaesthesia was induced and maintained as total intravenous anaesthesia using propofol, alfentanil and cis-atracurium. In addition, the patient was treated intraoperatively with hydrocortisone (initial bolus of 50 mg followed by a continuous infusion of 4.8 mg/h) and insulin (continuous infusion of 2 IE/h) in order to manage the adrenocortical insufficiency as well as to treat the diabetes mellitus. Using this anaesthetic technique, satisfactory haemodynamic and metabolic conditions were achieved during surgery. The postoperative period, however, was marked by severe respiratory complications.

Sequential effects of propofol on functional brain activation induced by auditory language processing: an event-related functional magnetic resonance imaging study.

BACKGROUND: We have investigated the effect of propofol on language processing using event-related functional magnetic resonance imaging (MRI). METHODS: Twelve healthy male volunteers underwent MRI scanning at a magnetic field strength of 3 Tesla while performing an auditory language processing task. Functional images were acquired from the perisylvian cortical regions that are associated with auditory and language processing. The experiment consisted of three blocks: awake state (block 1), induction of anaesthesia with 3 mg kg(-1) propofol (block 2), and maintenance of anaesthesia with 3 mg kg(-1) h(-1) propofol (block 3). During each block normal sentences and pseudo-word sentences were presented in random order. The subjects were instructed to press a button to indicate whether a sentence was made up of pseudo-words or not. All subjects stopped responding during block two. The data collected before and after the subjects stopped responding during this block were analyzed separately. In addition, propofol plasma concentrations were measured and the effect-site concentrations of propofol were calculated. RESULTS: During wakefulness, language processing induced brain activation in a widely distributed temporofrontal network. Immediately after unresponsiveness, activation disappeared in frontal areas but persisted in both temporal lobes (block 2 second half, propofol effect-site concentration: 1.51 microg ml(-1)). No activation differences related to the task were observed during block 3 (propofol effect-site concentration: 4.35 microg ml(-1)). CONCLUSION: Our findings suggest sequential effects of propofol on auditory language processing networks. Brain activation firstly declines in the frontal lobe before it disappears in the temporal lobe.

[Clonidine vs. Midazolam for premedication - comparison of the anxiolytic effect by using the STAI-test]. / Clonidin vs. Midazolam zur Prämedikation - Vergleich des anxiolytischen Effeketes mittels STAI-Test.

OBJECTIVE: Many investigations described a positive effect of clonidine for premedication (reduction of perioperative stress response, analgetic effect, anaesthetic-saving effect, prophylaxis of postoperative shivering). The most important objective in premedication is undisputed anxiolysis. The anxiolytic effect of clonidine is differently discussed. Therefore we investigated the anxiolytic effect of clonidine in comparison to midazolam. METHODS: 50 patients (ASA 1 - 3) were included in the present doubleblinded, prospective study. These patients got an oral premedication with 1 mg flunitrazepam in the evening before surgery and 5 microg/kg(-1) clonidine or 100 microg/kg(-1) midazolam 60 - 90 minutes before surgery. By using Spielbergers State-Trait Anxiety Inventory (STAI-G X1) we registered the degree of state-anxiety before and after premedication. RESULTS: Both clonidine as well as midazolam showed a significant reduction of the state-anxiety over time (p < 0,001). Between the groups there were no differences in the STAI-scores at any time (p > 0,05). The degree of reduction in the state-anxiety were comparable between the groups. CONCLUSION: In addition to the higher up listed effects clonidine showed a anxiolytic effect, which is comparable to midazolam. Therefore clonidine is an interesting alternative to benzodiazepines, which are commonly used drugs for premedication.

Subanesthetic isoflurane affects task-induced brain activation in a highly specific manner: a functional magnetic resonance imaging study.

BACKGROUND: Functional magnetic resonance imaging of blood oxygenation level-dependent signal changes offers a very promising approach to investigate activated neural networks during anesthesia. METHODS: Sixteen healthy male volunteers, assigned into two groups of eight subjects (isoflurane group, control group), were investigated by functional magnetic resonance imaging during different experimental conditions. The isoflurane group successively breathed air (baseline condition), isoflurane in air (0.42 vol% inspiratory; isoflurane condition) and air again (recovery condition) while performing a visual search task, whereas the control group breathed air during all experimental conditions. Functional magnetic resonance images were acquired during the entire experimental session. In addition, reaction times and error rates were recorded. RESULTS: A significant isoflurane-related decrease (z > 3.1 corresponding to P < 0.001) in task-induced brain activation was found in three distinct cortical regions: the right anterio-superior insula (Talairach coordinates: x = 32, y = 22, z = 8) and the banks of the left and right intraparietal sulcus (Talairach coordinates: x = -34, y = -36, z = 32; x = 22, y = -60, z = 41, respectively). Subcortical structures (lateral geniculate nucleus) and the primary cortices (motor cortex, visual cortex) were not affected. All measured parameters indicated a nearly complete recovery of the affected networks within 5 min. CONCLUSIONS: Our findings indicate that subanesthetic isoflurane affected task-induced activation in specific neural networks rather than causing a global decrease in functional activation.

[Value of magnetic resonance tomography for interventions in the ENT specialty]. / Die Nutzung der Magnetresonanztomographie bei Interventionen auf dem Gebiet der HNO-Heilkunde.

PURPOSE: Presentation of new concepts and applications of MR-guided head and neck surgery are presented. Examples of diagnostic and therapeutic procedures such as evaluation of transseptal tumor biopsies, placement of afterloading catheters for brachytherapy, and microscopic surgery of paranasal sinuses in the open MRI are discussed. MATERIAL AND METHODS: 24 MRI-guided ENT-procedures (14 transsphenoidal biopsies, one transnasal biopsy, 6 placements of brachytherapy catheters, and 3 operations of the paranasal sinuses) were performed in an open 0.5 T MR system. RESULTS: Localisation and/or extension of all lesions as well as the placement of biopsy needles or catheters were determined with great precision during the interventions. CONCLUSIONS: Surgical risk and postoperative morbidity are significantly reduced in MR-guided surgery of the petroclival region and the region of head and neck compared to other, conventional methods. Thus, interventional MRI-guidance optimizes minimal invasive surgery and catheter placement in difficult anatomical regions like the petroclival region.

[Effect of normobaric hyperoxia on parameters of brain metabolism]. / Der Einfluss von normobarer Hyperoxie auf Parameter des Hirnstoffwechsels.

In the literature there is only little information about the influence of hyperoxia on cerebral metabolic parameters. The aim of our study was to examine the effect of increased inspiratory oxygen concentrations on parameters of brain metabolism in elective neurosurgical patients. Ten patients undergoing an elective craniotomy for brain tumour resection were included in the study. The inspiratory oxygen concentration was raised at intervals of 15 minutes from 0.4 to 0.6 to 1.0 before opening the skull under "relative steady state conditions". At five defined measuring points, a blood gas analysis and an analysis of lactate and glucose levels were performed from arterial and jugularvenous blood. The lactate oxygen index (LOI), the arterio-jugularvenous lactate difference (AJDL) and the oxygen content of the arterial (caO2) and jugularvenous (cjO2) blood were calculated. Under increasing levels of FiO2, one can see an increase in sjO2, of jugularvenous oxygen tension (pjO2) and in oxygen content (cjO2). The most important result is the significant decrease (10% from baseline) in jugularvenous lactate at FiO2 1.0, while arterial lactate did not change significantly nor did the following parameters: paCO2, pjCO2, LOI, modified LOI, arterial and jugularvenous glucose. Hyperoxia causes a possible shift to aerobic metabolic situation in the brain reflected by decreased jugularvenous lactate.

[Is the combination of nitrous oxide and hyperventilation in elective neurosurgical operations useful?]. / Ist die Kombination von Lachgas und Hyperventilation bei elektiven neurochirurgischen Operationen sinnvoll?

The use of nitrous oxide (N2O) and hyperventilation (HV) in elective neurosurgery is controversially discussed. The emphasis of the study was to show the effects of N2O and/or moderate hyperventilation (paCO2 31.0 +/- 1.2 mmHg) on parameters of cerebral metabolism: jugularvenous oxygen saturation (SjVO2), cerebral extraction of oxygen (CEO2), arterial jugularvenous difference of oxygen contents (AJDO2), arterial jugularvenous difference of lactate (AJDL) and glucose (AJDGL) and lactate-oxygen index (LOI). The study was approved by the Ethics Committee of the University of Leipzig. Forty patients undergoing an elective craniotomy for brain tumour resection were divided into four groups: group 1: n = 10, N2O + normoventilation (NV), group 2: n = 10, N2O + hyperventilation (HV), group 3: n = 10, O2/air + NV, group 4: n = 10, O2/air + HV. N2O + HV led to a significant decrease in SjVO2 from 68.1 +/- 10.7% to 49.7 +/- 5.6%. O2/Air + HV produced a drop from 67.1 +/- 11.1% to 49.8 +/- 7.7%. CEO2 increased significantly in the group N2O + HV from 30.6 +/- 10.6% to 49.6 +/- 5.5% and in the group O2/Air + HV from 31.7 +/- 11.1% to 50.0 +/- 7.8%. AJDO2 increased significantly in the group N2O + HV from 5.79 +/- 1.54 ml% to maximal 8.49 +/- 1.10 ml% and in the group O2/Air + HV from 5.29 +/- 1.76 ml% to maximal 8.03 +/- 1.76 ml%. In the normoventilation-groups 1 and 3, no significant changes in SjVO2, CEO2 and AJDO2 were observed between MP2 and 4. The parameters AJDL, AJDGL and LOI did not show any significant changes in any of the four groups. The described data represent a reduction of cerebral oxygenation, but deleterious effects caused by cerebral ischaemia could not be observed. Based on our data, hyperventilation and its combination with N2O should not be used routinely in neuroanaesthesia.

[Preemptive effects caused by co-analgesia with ketamine in gynecological laparotomies?]. / Präemptive Effekte durch Ko-Analgesie mit Ketamin bei gynäkologischen Laparotomien?

The preemptive use of analgetics makes it possible to influence sensitization proceedings caused by a trauma. Various mechanisms are effective in central pain treatment. The NMDA receptor plays an important role. The investigation presented was to examine whether an intraoperative combination of analgetics with different points of contact leads to improved postoperative analgesia. Altogether 39 female patients who had to undergo a gynaecological laparotomy were examined. Three groups of 13 patients were randomly formed. In addition to usual general anaesthesia, the patients of group one received 0.5 mg/kg bodyweight ketamine racemate before the skin incision and thereafter 10 micrograms/kg/min ketamine infusion continuously until peritoneum closure and then sodium chloride 0.9% as a placebo after the final skin suture. The patients of group two received placebos before the skin incision and intraoperatively and 0.5 mg/kg bodyweight ketamine after the last skin suture. In group three the patients received placebos at all three points of time. Analgetics consumption, pain intensity, awakening reaction, vital parameters as well as psychomimetic side-effects and nausea/vomiting were listed postoperatively. Between the groups no differences were found regarding postoperative analgetics consumption. In addition, the pain intensity showed no differences regarding an improved postoperative analgesia through the combination of analgetics with different points of contact. The intraoperative combination of ketamine and alfentanil does not lead to a reduction of postoperative pain. No preemptive analgesia is clinically provable.

Investigating the dependence of BOLD contrast on oxidative metabolism.

Most functional magnetic resonance imaging (fMRI) studies are based on measuring the changes in the blood oxygenation level-dependent (BOLD) contrast that arise from a complex interplay between cerebral hemodynamics and oxidative metabolism. To separate these effects, we consecutively applied two different stimuli: visual stimulation (black/white checkerboard alternating with a frequency of 8 Hz) and hypercapnia (inspiration of 5% CO2). Changes in cerebral blood flow (deltaCBF) and the effective transverse relaxation time (T2*) were measured in an interleaved manner by combining a previously described spin-labeling technique with BOLD-based fMRI. In six healthy volunteers, T2* was significantly longer during hypercapnia than during visual stimulation, whereas the corresponding deltaCBF values were the same at the given level of significance (P<0.01). This finding is explained by a significant increase in oxygen consumption under visual stimulation. The average T2* changes in the visual cortex related to cerebral hemodynamics and oxidative metabolism were 10.6+/-3.0% and -4.7+/-1.2%, respectively, resulting in a net increase of 5.9+/-2.3%. Although the hemodynamic effect is dominant, the increase in oxidative metabolism gives rise to a significant decrease in BOLD contrast. The calculated average change in the cerebral metabolic rate of oxygen (CMRO2), 4.4+/-1.1% (N = 6), is in excellent agreement with previous results obtained by positron emission tomography.

The effect of different ventilation regimes on jugular venous oxygen saturation in elective neurosurgical patients.

Since the concept of hyperventilation on neurosurgical and neurotraumatological patients has been contested, our analysis was aimed at its scrutiny on the basis of easily accessible parameters of perisurgical monitoring. Furthermore, the influence of an improved oxygen supply was tested on hyperventilationally induced cerebral changes and to what extent recommendations could be derived for clinical application. In 50 patients (normoventilation FiO2 = 0.4, 0.6; moderate hyperventilation up to a value of paCO2 = 31 mmHg and FiO2 = 0.4, 0.6 and 0.8), who underwent an elective neurosurgical operation at the central nervous system, a fiberoptical catheter was inserted into the bulb of the jugular vein for the continuous monitoring of the jugular venous oxygen saturation (sjvO2), additionally to the regular measures of perioperative monitoring. Approval for this study was given by the Ethics Committee of the University of Leipzig. At five defined times an analysis of arterial and jugular venous blood gas samples was made and their lactate and glucose concentration determined: 1. Immediately after inducing anesthesia; 2. After dura opening; 3. Sixty minutes after dura opening; 4. At dura closing; 5. Sixty minutes after the end of the operation. The lactate oxygen index (LOI) as well as the cerebral oxygen extraction (CEO2) were calculated from primary data. Hyperventilation with a value of FiO2 = 0.4 leads to a significant decrease of the jugular venous oxygen saturation below 55%. It can be positively influenced by increasing the inspiratory oxygen concentration from 40% to 60%. The CEO2 increases, above values of 42% under a hyperventilation of FiO2 = 0.4. This effect can be reversed by increasing the FiO2 value up to 0.6. Under hyperventilation the LOI reaches 'pre-ischemic' values (LOI > 0.03) prior to dura opening. Further decrease of FiO2 to 0.8 has no positive additional effect. Normoventilation with FiO2 = 0.6 induces a decrease of sjvO2 but also a decrease of LOI. Hyperventilation as a routine procedure during elective neurosurgery shall be applied critically and be combined with an increased inspiratory oxygen concentration if necessary. A longterm normoventilation with increased FiO2 should be avoided.

BASE imaging: a new spin labeling technique for measuring absolute perfusion changes.

A new technique for magnetic resonance imaging of absolute perfusion changes that uses magnetically labeled tissue water proton spins as a freely diffusible tracer is described. It consists of unprepared basis (BA) images that serve as a reference and selective (SE) inversion prepared images that are sensitive to perfusion changes. In the present study, the BASE technique was applied to functional neuroimaging. BA and SE images were alternatingly and repeatedly acquired during periods of visual stimulation and control. Visual stimulation was achieved with an alternating black/white checkerboard operating at a frequency of 8 Hz. Maps of the absolute cerebral blood flow changes (deltaCBF) were calculated from the image intensities of the corresponding BA and SE images. The individual mean values of deltaCBF measured in five healthy volunteers ranged from 69 +/- 18 to 99 +/- 26 ml/min/100 g. Since the BASE technique does not require nonselective spin inversion, it can be used with small transmit/receive head coils (e.g., surface coils). In addition, the BASE technique is robust against a mismatch of the inversion and detection slice profiles.

[Postoperative vomiting after pars plana vitrectomy]. / Postoperatives Erbrechen nach Pars-plana-Vitrektomien.

In the present investigation we compared two different techniques of anaesthesia--total intravenous anaesthesia (TIVA) versus balanced anaesthesia--with and without antiemetic prophylaxis, with regard to postoperative nausea, strangling irritation and vomiting and their influence upon postoperative complications (intraocular bleedings) and postoperative intraocular pressure after pars plana vitrectomia. For this investigation four groups were formed. The anaesthesias were carried out as orotracheal intubational anaesthesia following two standard techniques, which only differ in the choice of the narcotics. Half the patients in each group were treated with an antiemetic prophylaxis of 2.5 mg DHBP. With regard to the occurrence of postoperative nausea and vomiting, the TIVA-groups proved to be better than those with balanced anaesthesia (16% to 43.5%; p < 0.05): DHBP in both methods led to a reduction of postoperative vomiting and nausea, but the differences showed not to be significant (p > 0.05). Best results were achieved with a combination of TIVA (propofol, alfentanil, atracurium, air/O2) and DHBP (4.7%). The total rate of postoperative complications in form of intraocular bleedings amounted to 8.6%. The appearance of complications increased when postoperative nausea and vomiting or increased intraocular pressure were observed (16.6% to 6.3%; 21.2% to 6.1%). Intraocular pressure, measured for four hours postoperatively, was significantly lower in the TIVA-groups than in the balanced anaesthesia-groups (15.5 +/- 7.7 mmHg to 18.3 +/- 8.2 mmHg). Therefore, we conclude that TIVA with propofol appears to be especially suitable for intraocular surgery.