Biomedical subjects

A Timmermann

Publications and source records attributed to A Timmermann.

At least 19 recordsLinked to original sources

PubMed2007

[Teaching and simulation. Methods, demands, evaluation and visions].

Since 1st October 2003 the new German "Approbationsordnung für Arzte" (Medical Licensing Regulations) requires an increasing amount of small group teaching sessions and encourages a multidisciplinary and more practical approach to the related topics. In 2004 the German Society of Anaesthesiology and Intensive Care Medicine has provided almost all anaesthesia faculties of German Universities with equipment for full-scale simulation. This article describes methods for a simulation-based medical education training program. Basic requirements for a successful training program using full scale simulators are the provision of an adequate logistical and material infrastructure, teacher attendance of train-the-trainer courses, implementation in the medical curriculum and an instructor-student ratio of 1:3, equivalent to that for bedside teaching. If these requirements were fulfilled, medical students scored the simulation scenarios "induction of anaesthesia", "acute pulmonary embolism", "acute management of a multiple trauma patient" and "postoperative hypotension" as 1.5, 1.6, 1.5 and 1.5, respectively, on a scale of 1-6. These scores were better than those given for other segments of the curriculum.

Anesthesia↗

PubMed2006

Evaluation of the CTrach--an intubating LMA with integrated fibreoptic system.

BACKGROUND: The laryngeal mask airway CTrach (CTrach) is a variant of the intubating laryngeal mask airway. It provides visualization of the larynx during intubation and is designed to increase the success rates of ventilation and tracheal intubation. METHODS: Sixty healthy anaesthetized and paralysed patients with normal airways were studied. The success rates of ventilation and intubation using CTrach were determined. Laryngeal view scoring ranged from grade I (full view of arytenoids and glottis), II (arytenoids and glottis partly visible), III (view of arytenoids, glottis or epiglottis blurred, or view clear with only epiglottis visible) to IV (no part of larynx identifiable). Adjusting manoeuvres were undertaken to improve the laryngeal view in grades II or worse. RESULTS: CTrach insertion and ventilation was possible in all patients. Initial views were scored as grade I in 22 (36.7%), grade II in 14 (23.3%), grade III in 7 (11.7%) and grade IV in 17 (28.3%) patients. Adjusting manoeuvres were undertaken in 38 patients with grade II and worse (63.3%), resulting in improved views of grade I in 33 (55.0%), grade II in 18 (30.0%), grade III in 4 (6.7%) and grade IV in 5 (8.3%) patients. Tracheal intubation was successful in 58 (96.6%) patients at first attempt and in one at second. Tracheal intubation failed once. CONCLUSIONS: In 60 patients with normal airways, the CTrach was used successfully for ventilation, with successful tracheal intubation in 59 patients. Tracheal intubation can be successful despite grade III or IV views.

Adolescent↗

PubMed2006

[New perspectives for simulator-based training in paediatric anaesthesia and emergency medicine].

Anaesthesia and emergency medical care for infants and toddlers is often associated with high clinical demands and specific challenges. Nevertheless, a significant proportion of interventions is performed by anaesthetists and emergency physicians with no specialised paediatric training and little experience in the management of anaesthetic incidents and emergencies specific to these age groups. Extensive studies have demonstrated a close inverse correlation between the level of specialisation and perioperative morbidity and mortality. However, clinical circumstances and the relatively small number of paediatric cases at many institutions often hinder the establishment of improved training concepts. Recently, high-fidelity infant simulators have become available, which permit authentic exposure to a large spectrum of scenarios in paediatric anaesthesia and emergency medicine. A multimodular concept of training, including such simulator-based techniques, may relieve the widespread shortage in clinical experience, and hence greatly facilitate improvement of quality of care and patient safety.

Anesthesiology↗

PubMed2006

[LMA CTrach: initial experiences in patients with difficult-to-manage airways].

BACKGROUND: The Intubating LMA was designed to facilitate blind intubation and to provide ventilation between two intubation attempts. However, blind intubation can be associated with a risk of oesophageal penetration, therefore, a flexible bronchoscope is frequently used to assist tracheal intubation. This leads to increased burdens on materials and personal resources and prolongs intubation times. Hence the LMA CTrach laryngeal mask airway (CTrach) was developed with an integrated fibreoptic system which can be connected to a monitor for visualisation of the larynx during intubation. METHODS: We detail the initial experience gained with the practical handling of the CTrach and the application in 10 patients with difficult-to-manage airways. Laryngeal views were graduated in a CTrach-specific classification from grade I (clear view of the arytenoids, glottis and epiglottis) to grade IV (no part of the larynx can be identified). Adjusting manoeuvres were defined to improve the view of laryngeal structures. RESULTS: All patients could be successfully ventilated with the CTrach. Ventilation quality was rated adequate in nine and possible in one patient. The initial distribution of the laryngeal view between grades I-IV was 1/2/1/6 and after adjusting manoeuvres to improve the laryngeal view the grade distribution was 3/5/0/2. Intubation through the CTrach was successful in all patients, nine at first and one at the second attempt. CONCLUSION: In this small sample of patients with difficult-to-manage airways, the CTrach yielded high success rates for both ventilation and tracheal intubation. Adjusting manoeuvres can improve the laryngeal view further.

Anesthesia, Inhalation↗

PubMed2005

[Simulation and airway management].

Despite the development of new devices and strategies to manage and secure the difficult airway, morbidity and mortality in anaesthesia due to airway problems such as difficult intubation or unrecognised failed intubation remain high. The problem seems to lie in the transfer of skills and strategies to daily clinical practice. Common methods for airway management training include theoretical instructions and hands-on sessions with manikins, animal models and cadavers. Simulation provides the opportunity to train skills and resolve specific situations embedded in a realistic scenario, facilitate the transfer of cognitive, psychomotor and affective abilities into daily clinical practice and help to improve behaviour in critical situations. This article outlines new training concepts in airway management with the help of simulation and simulators. We describe technical prerequisites and provide information on the implementation of difficult airway scenarios.

Anesthesiology↗

PubMed2005

[Accidental hypothermia in the household environment. Importance of preclinical temperature measurement].

In emergency medicine accidental hypothermia in non-traumatized patients is a rare situation. To emphasize the need for a precise preclinical temperature measurement, two cases of accidental hypothermia (28.2 degrees C and 29.3 degrees C core temperature) are presented which occurred under conditions that did not give a direct suspicion of hypothermia. In one case the immediate diagnosis lead to complete convalescence, the other patient died of multiple organ failure. The primary diagnosis, diagnostic methods and therapy as well as the primary treatment are discussed.

Accidents↗

PubMed2005

[The applicability of the ProSeal laryngeal mask airway for laparotomies].

OBJECTIVE: The ProSeal laryngeal mask airway (PLMA) has some design features, which in contrast to the classic LMA allow separation of the respiration from the gastrointestinal canal, a higher leak pressure and a better position assessment. It can be debated if these instrumental improvements justify the application of the PLMA for elective abdominal surgery in cases without aspiration risk. Insertion of airway instruments and gastric tube with regard to insertion time and difficulties and frequency of side effects were to be compared for the tracheal tube and the PLMA. The pharyngolaryngeal morbidity for both methods was also of interest. It was approached with direct and indirect postoperative interview techniques. METHODS: 65 patients were investigated both at the university hospital and at the hospital Neu-Bethlehem in Goettingen. The surgical intervention was a surgical or gynecological laparotomy. Anaesthesia was performed with a standardized application of propofol, alfentanil and rocuronium. Glycopyrroniumbromide was applied to minimize salivation. A total of 34 patients received the PLMA, 31 were intubated. All of them were provided with a gastric tube. RESULTS: The insertion of the PLMA took 70 seconds (21 - 234) on average, the intubation 57 seconds (35 - 145). Endotracheal intubation was accomplished in a shorter time period, but there was no significant difference in comparison with the PLMA-group (p = 0.1924). Insertion of the PLMA was significantly more difficult than oral intubation (p = 0.0006). The base of the tongue and the dorsal pharyngeal wall, but not the vocal cords or the epiglottis were visible in those cases, where the PLMA could not be positioned at all. Here the tip of the cuff was bended. The time period for positioning of the gastric tube was 38 seconds (15 - 75) in the PLMA- and 57 seconds (22 - 219) in the tracheal tube group. With these results the gastric tube positioning was accomplished in a significantly shorter time period in the PLMA-group (p = 0.0267), but not at a significantly higher level of difficulty for endotracheal intubation (p = 0,6247). In one case there was regurgitation through the drainage tube without aspiration before gastric tube placement. At the direct interview 16 patients in the PLMA-group and 23 of the tube group mentioned postoperative throat symptoms. The most frequent symptom was hoarseness (11 PLMA- and 18 intubated patients). There was no significant difference between PLMA- and tracheal tube application with regard to the total number of patients with pharyngolaryngeal morbidity and the frequency of single symptoms. The same is true for the degree of the symptoms. There was a tendency for a longer prevalence of throat symptoms after intubation, but no significant difference. CONCLUSION: In this investigation the PLMA could be successfully applied for elective laparotomies in cases without the risk of aspiration. Proper patient selection and a deep level of anaesthesia are important. The advantage for patients receiving the PLMA is a smooth recovery without cough, but not so much a reduced amount of pharyngolaryngeal morbidity. From this observation it might be concluded that the invasiveness of the surgical intervention might also influence the tolerance for the airway instrument. The disadvantage in this study was the more difficult insertion of the PLMA compared with the oral intubation. Further studies with a larger number of patients must show if these first results of the "Proseal"-LMA for lararotomies are to be confirmed.

Adolescent↗

PubMed2005

[New pathways in undergraduate medical education - first experiences with the cross section speciality emergency and intensive care medicine].

OBJECTIVE: On October 1 (st) 2003 Emergency Medicine was recognised for the first time as an independent cross section speciality in the new German "Approbationsordnung fuer Aerzte" (Medical Licensing Regulations). These amendments were made not only to increase the amount of small group teaching sessions but also to encourage a multidisciplinary and rather practical approach to the related topics. This article portrays the realisation of these objectives in form of a multidisciplinary module, as it has been established at University of Göttingen Medical School since the summer semester of 2004. We present the new curriculum, calculate the associated personnel resources and demonstrate the results of the structured evaluation given by the participating students. METHODS: We linked the fields of emergency and intensive care medicine by splitting them up into submodules which the students had to run through according to a set rota. 162 students were allocated to 27 small groups. Every student received a total of 38.5 hours of teaching, with the workshops coming to 46.8 %. The workshops comprised of nine sessions, three in Emergency Medicine, four in Intensive Care Medicine and two at human patient simulators. In addition we scheduled a seminar and an accompanying lecture. The final examination was performed as an Objective Structured Clinical Evaluation (OSCE). RESULTS: The realisation of the new module required a total of 1290 working hours for medical staff and 130 for our student aids. Compared to all other modules of Goettingen University Medical School the module here presented obtained the highest overall evaluation score by the medical students. Lessons with a high amount of practical involvement (i. e. Emergency Medicine and simulator-based workshops) were significantly better evaluated than rather formal teaching techniques, such as the lectures and the seminar. According to the students' self-assessment the simulator-based workshops were seen particularly valuable for the facilitation of knowledge transfer into clinical practice. CONCLUSION: The determined realisation of the new German Medical Licensing Regulations requires considerable time resources. However, its evaluation by the medical students is strikingly positive.

Anesthesiology↗

PubMed2004

Strong hemispheric coupling of glacial climate through freshwater discharge and ocean circulation.

The climate of the last glacial period was extremely variable, characterized by abrupt warming events in the Northern Hemisphere, accompanied by slower temperature changes in Antarctica and variations of global sea level. It is generally accepted that this millennial-scale climate variability was caused by abrupt changes in the ocean thermohaline circulation. Here we use a coupled ocean-atmosphere-sea ice model to show that freshwater discharge into the North Atlantic Ocean, in addition to a reduction of the thermohaline circulation, has a direct effect on Southern Ocean temperature. The related anomalous oceanic southward heat transport arises from a zonal density gradient in the subtropical North Atlantic caused by a fast wave-adjustment process. We present an extended and quantitative bipolar seesaw concept that explains the timing and amplitude of Greenland and Antarctic temperature changes, the slow changes in Antarctic temperature and its similarity to sea level, as well as a possible time lag of sea level with respect to Antarctic temperature during Marine Isotope Stage 3.

Journal Article↗

PubMed2003

Differences among forced-air warming systems with upper body blankets are small. A randomized trial for heat transfer in volunteers.

BACKGROUND: Forced-air warming is known as an effective procedure in prevention and treatment of perioperative hypothermia. Significant differences have been described between forced-air warming systems in combination with full body blankets. We investigated four forced-air warming systems in combination with upper body blankets for existing differences in heat transfer. METHODS: After approval of the local Ethics Committee and written informed consent, four forced-air warming systems combined with upper body blankets were investigated in a randomized cross-over trial on six healthy volunteers: (1) BairHugger trade mark 505 and Upper Body Blanket 520, Augustine Medical; (2) ThermaCare trade mark TC 3003, Gaymar trade mark and Optisan trade mark Upper Body Blanket, Brinkhaus; (3) WarmAir trade mark 134 and FilteredFlow trade mark Upper Body Blanket, CSZ; and (4) WarmTouch trade mark 5800 and CareDrape trade mark Upper Body Blanket, Mallinckrodt. Heat transfer from the blanket to the body surface was measured with 11 calibrated heat flux transducers (HFTs) with integrated thermistors on the upper body. Additionally, the blanket temperature was measured 1 cm above the HFT. After a preparation time of 60 min measurements were started for 20 min. Mean values were calculated over 20 min. The t-test for matched pairs with Bonferroni-Holm-correcture for multiple testing was used for statistical evaluation at a P-level of 0.05. The values are presented as mean+/-SD. RESULTS: The WarmTouch trade mark blower with the CareDrape trade mark blanket obtained the best heat flux (17.0+/-3.5 W). The BairHugger trade mark system gave the lowest heat transfer (8.1+/-1.1 W). The heat transfer of the ThermaCare trade mark system and WarmAir trade mark systems were intermediate with 14.3+/-2.1 W and 11.3+/-1.0 W. CONCLUSIONS: Based on an estimated heat loss from the covered area of 38 W the heat balance is changed by 46.1 W to 55 W by forced-air warming systems with upper body blankets. Although the differences in heat transfer are significant, the clinical relevance of this difference is small.

Adult↗

PubMed2002

Construction and evaluation of a manikin for perioperative heat exchange.

BACKGROUND: During surgery hypothermia can be avoided only if the heat exchange between the body surface and the environment can be controlled. To allow a systematic analysis of this heat exchange, we constructed and evaluated a copper manikin of the human body. METHODS: The manikin consists of six tubes (head, trunk, two arms and two legs) painted matt-black to simulate the emissivity of the human skin. Hot-water mattresses are bonded to the inner surface of the copper tubes to set the surface temperature. Calibrated heat flux transducers were placed on the following points to determine the heat exchange coefficient for radiation and convection (hRC) of the manikin: Forehead, chest, abdomen, upper arm, forearm, dorsal hand, anterior thigh, anterior leg and foot. Room temperature was set to 22 degrees C. Surface temperature of the manikin was set between 22 degrees C and 38 degrees C. The hRC was determined by linear regression analysis as the slope of the temperature gradient between the manikin and the room versus the measured heat flux. Subsequently we studied five minimally clothed volunteers in a climate chamber. Initial chamber temperature was set to 29 degrees C and was lowered slowly to 12 degrees C. The hRC was determined as described above for each volunteer. RESULTS: The hRC of the manikin was 11.0 W m(-2) degrees C(-1) and hRC of the volunteers was 10.8 W m(-2) degrees C(-1). CONCLUSION: The excellent correlation of hRC between the volunteers and the manikin will allow the manikin to be used for standardised studies of perioperative heat exchange.

Adult↗

PubMed2001

Radical transfer hydrosilylation/cyclization using silylated cyclohexadienes.

[reaction: see text] A new method for mild metal-free hydrosilylation is described. Silylated cyclohexadienes are used as radical transfer hydrosilylating reagents for various double and triple bonds. A trialkylsilane is transferred from a cyclohexadiene moiety to an alkene. The hydrosilylation can be combined with a C-C bond formation as shown for the preparation of silylated cycloalkanes from the corresponding dienes.

Journal Article↗

PubMed2001

Role of growth factors in rabbit articular cartilage repair by chondrocytes in agarose.

OBJECTIVE: Novel approaches to intervention in joint diseases consist of the replacement of diseased cartilage by in vitro engineered, viable cells or graft tissues. Two major obstacles remain to be overcome: (1) Hyaline cartilage in vitro often loses differentiated traits. (2) Grafts frequently are not integrated satisfactorily into host cartilage and/or the tissue is remodelled in situ into functionally inferior fibrocartilage. Therefore, we have explored the possibility whether chondrocytes embedded into agarose gels provided better graft tissues in a repair model of full thickness defects in rabbit joint cartilage. DESIGN: Experimental defects of knee joint cartilage was filled with articular chondrocytes cultured in agarose gels. Chondrocytes in vitro either remained unstimulated or were treated with several growth factors. Repair of the defects was assessed by histology and was scored between 0 (no healing) and 1 (perfect healing) as judged by the follwing parameters: intensity of proteoglycan staining, organization of the superficial zone, ossification at the border between repair cartilage and subchondral bone, tidemark formation in the repaired area, arrangement of chondrocytes, and integration of repair cartilage into host. RESULTS: Treatment of chondrocyte cultures with bFGF had a stabilizing effect on the differentiated state of the cells in implanted grafts whereas bone morphogenetic proteins stimulated ingrowth of subchondral bone reducing repair cartilage thickness and preventing normal tide mark formation; TGF-beta did not significantly affect evaluation parameters in comparison with untreated controls. CONCLUSION: Growth factor treatment resulted in an ambiguous quality of graft development. Only FGF had a clear beneficial effect to the graft tissues after 1 month. Further studies are required to define the precise conditions and sequence of growth factor treatment of in vitro engineered cartilage which benefits graft quality.

Animals↗

PubMed2000

Different epitopes are required for gp130 activation by interleukin-6, oncostatin M and leukemia inhibitory factor.

Gp130 is the common signal transducing receptor subunit of interleukin (IL)-6, IL-11, leukemia inhibitory factor (LIF), oncostatin M (OSM), ciliary neurotrophic factor and cardiotrophin-1. IL-6 and IL-11 induce gp130 homodimerization whereas the others lead to the formation of heterodimers with LIFR or OSMR. Binding epitopes for IL-6 and IL-11 are located in the immunoglobulin-like domain and the cytokine binding module (CBM). Here we show that a gp130 mutant lacking domain 1, although unresponsive to IL-6 and IL-11, can still activate signal transducer and activator of transcription (STAT) transcription factors in response to LIF or OSM. Moreover, point mutations in the CBM of gp130 (F191E and V252D) that severely impair signal transduction in response to IL-6 and IL-11 differentially interfere with gp130 activation in response to LIF and OSM. Thus, epitopes involved in gp130 homodimerization are distinct from those leading to the formation of gp130/LIFR or gp130/OSMR heterodimers. These findings may serve as the base for rational design of gp130 antagonists that specifically interfere with bioactivity of distinct IL-6-type cytokines.

Animals↗

PubMed2000

Importance of the membrane-proximal extracellular domains for activation of the signal transducer glycoprotein 130.

The transmembrane glycoprotein gp130 is the common signal transducing receptor subunit of the IL-6-type cytokines. The gp130 extracellular part is predicted to consist of six individual domains. Whereas the role of the three membrane-distal domains (D1-D3) in binding of IL-6 and IL-11 is well established, the function of the membrane-proximal domains (D4-D6) is unclear. Mapping of a neutralizing mAb to the membrane-proximal part of gp130 suggests a functional role of D4-D6 in receptor activation. Individual deletion of these three domains differentially interferes with ligand binding of the soluble and membrane-bound receptors. All deletion mutants do not signal in response to IL-6 and IL-11. The deletion mutants Delta4 and, to a lesser extent, Delta6 are still activated by agonistic monoclonal gp130 Abs, whereas the deletion mutant Delta5 does not respond. Because membrane-bound Delta5 binds IL-6/soluble IL-6R as does wild-type gp130, but does not transduce a signal in response to various stimuli, this domain plays a prominent role in coupling of ligand binding and signal transduction. Replacement of the fifth domain of gp130 by the corresponding domain of the homologous G-CSF receptor leads to constitutive activation of the chimera upon overexpression in COS-7 cells. In HepG2 cells this mutant responds to IL-6 comparable to wild-type gp130. Our findings suggest a functional role of the membrane-proximal domains of gp130 in receptor activation. Thus, within the hematopoietic receptor family the mechanism of receptor activation critically depends on the architecture of the receptor ectodomain.

Animals↗

PubMed2000

The influence of airway pressure changes on intracranial pressure (ICP) and the blood flow velocity in the middle cerebral artery (VMCA).

OBJECTIVE: Due to the exponential shape of the intracranial volume-pressure relation, simple measurement of epidural, parenchymal or intraventricular intracranial pressure (ICP) in traumatic brain injury (TBI) often fails to early recognize patients with a fulminant development of intracranial hypertension even during recently available methods of tissue PO2 and microdialysis measurements. One approach to this problem could be repetitive intracranial volume provocations to evaluate a trend of the intracranial elastance. Several previously published methods use invasive volume challenge through access to the cerebrospinal fluid (CSF). This pilot study describes changes in intracranial pressure due to variations of airway pressure with BIPAP ventilation maneuvers. PATIENTS AND METHODS: Ten patients with severe TBI were enrolled and completed the study. The inclusion was based on radiologic signs due to TBI in the first CT-scan and the clinical indication for insertion of an ICP monitoring device. Patients with elevated ICP above 20 mm Hg were excluded. The epidural ICP response together with haemodynamic parameters in relation to defined airway pressure changes (delta PAW) was detected. The influence of the duration of delta PAW was evaluated additionally. Data of central venous pressure (CVP), ICP, mean arterial pressure (MAP), cerebral perfusion pressure (CPP), airway pressure (PAW) and blood flow velocity of the middle cerebral artery (VMCA) were analyzed on the basis of differences between the maximum (inspiration) and minimum PAW values (expiration). RESULTS: Elevations of PAW in the range of 20 to 35 cm H2O resulted in changes of the ICPmean from 4.1 to 6.0 mm Hg (r = 0.9, p < 0.05). A correlation was estimated for the changes of systolic arterial pressure (Part) and CPPmean due to PAW variations which ranged between 4.5 and 11.6 mm Hg (r = 0.99, p < 0.05). Concerning the transcranial doppler measurements the data of changes of the blood flow velocity of the middle cerebral artery (VMCA) revealed a positive correlation to PAW with a r = 0.99, p < 0.05. CONCLUSIONS: Elevation of the venous outflow resistance and a transient increase in cardiac output have to be considered as mechanisms for transduction of transthoracic pressure changes to intracranial pressure variations. We conclude, that trends of changes in elastance can be derived from intermittent airway pressure variations. This can be useful in easy and on line dynamic monitoring of ICP in traumatic brain injury.

Air Pressure↗

PubMed1999

Identification of a Leu-lle internalization motif within the cytoplasmic domain of the leukaemia inhibitory factor receptor.

Leukaemia inhibitory factor (LIF) signals via a heterodimeric receptor complex comprised of the LIF receptor (LIFR) and the interleukin (IL)-6 signal transducer gp130. Upon binding to its cognate receptor LIF is internalized. In this study, we show that the LIFR is endocytosed independently of gp130. By using a heterochimaeric receptor system we identified a dileucine-based internalization motif within the cytoplasmic domain of the LIFR. Our findings suggest that a heterodimeric LIFR/gp130 complex and homodimeric gp130/gp130 complex are endocytosed via distinct internalization signals.

Animals↗

PubMed1997

Anaphylatoxin C5a receptor mRNA is strongly expressed in Kupffer and stellate cells and weakly in sinusoidal endothelial cells but not in hepatocytes of normal rat liver.

Anaphylatoxins (C5a and C3a), which are generated during complement activation, have recently been shown to increase glucose output from hepatocytes (HC) in perfused rat liver. They did not act directly on HC but indirectly by prostanoid release from non-parenchymal cells (NPC), probably Kupffer cells (KC). In order to corroborate this mechanism, the distribution of anaphylatoxin receptors in the different cell types of rat liver was determined by quantitative RT-PCR with primers specific for the rat C5a receptor (rC5aR) using RNA isolated from KC, sinusoidal endothelial cells (SEC), hepatic stellate cells (HSC) and HC. In line with functional data, C5aR mRNA was detected in freshly isolated NPC but not in HC of rat liver. Mainly KC but also HSC clearly expressed C5aR mRNA, while SEC did so only weakly. KC expressed up to 10-fold more C5aR mRNA than HSC and these in turn up to 10-fold more than SEC. These results support the proposed indirect action of anaphylatoxins on HC.

Animals↗