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Biomedical subjects

N Roewer

Publications and source records attributed to N Roewer.

At least 19 recordsLinked to original sources
PubMed2006

Ultrasound-guided interscalene brachial plexus anaesthesia: differences in success between patients of normal and excessive weight.

UNLABELLED: Interscalene plexus blocks are an important part of the peri-operative treatment in shoulder surgery. The nerve stimulation technique uses external landmarks for the definition of the injection site. Patient obesity is, therefore, one causative factor for a reduced success rate of the blockade. AIM: This study investigated whether there are differences in visibility of the target nerves and in the success rate of the block between patients of normal weight (nw) and obese patients (ow), when portable sonography is used for guidance of the interscalene nerve blockade (ISB). METHODS: We investigated 70 patients routinely scheduled for shoulder surgery (ASA status I-III). The patients were allocated to group nw (body mass index BMI< 25) or ow (BMI > 25). The interscalene part of the brachial plexus was examined using high-frequency portable ultrasound. The blockade was performed under continuous sonographic monitoring. The quality of the ISB was tested post-operatively, and the time required for the procedure was documented. RESULTS: Identification of nerve structures in the obese patients did require slightly more time than in patients of normal weight, statistically (ow: 5 +/- 1 min versus nw: 4 +/- 2 min, p = 0.02). While in 33 patients (94 %) of group nw the plexus blockade was complete, in group ow 27 (77 %) of the blocks were sufficient. The difference in success, however, was not significant (p = 0.08). Visualisation of nerves was difficult in 3 patients in ow-group. CONCLUSION: Portable ultrasound provides efficient depiction of the interscalene plexus structures in obese patients and, when used for guidance of regional blockade, renders similar results as in patients of normal weight.

Adult↗
PubMed2006

Ultrasound-guided arterial cannulation in infants improves success rate.

BACKGROUND AND OBJECTIVE: In small children, the placement of arterial catheters can be technically challenging for even the most experienced anaesthetist. We investigated whether ultrasound imaging would improve the success rate and reduce time demand and complications of radial artery cannulation. METHOD: In this prospective randomized study, we performed radial artery cannulation in 30 small children (age 40 +/- 33 months) using two different techniques for localization of the vessel. In Group 1 (n = 15), the traditional palpation method was used, while in Group 2 (n = 15) cannulation was directed by vascular ultrasound imaging. In addition, we used ultrasound to determine the cross-sectional area of the radial artery with and without dorsiflexion. For statistical analysis, the non-parametric U-test for non-paired data and the Wilcoxon signed rank sum test for paired data were used. Differences were considered significant, when P < 0.05. RESULTS: Ultrasound-guided puncture was successful in all children of Group 2 compared to only 12 of 15 (80%) children in Group 1. Fewer attempts with the imaging technique were required than with the traditional technique (20 vs. 34, P < 0.05). Dorsiflexion significantly reduced the mean cross-sectional area of the artery by 19%. CONCLUSION: The current pilot study suggests that ultrasound guidance is appropriate for radial artery catheter insertion, sharing many of the benefits of ultrasound-guided central vein catheter insertion.

Catheterization, Peripheral↗
PubMed2006

[Management of seriously injured patients without conventional radiography? Does a whole body MSCT scanner replace the conventional X-ray unit in the emergency room?].

BACKGROUND: [corrected] In the Wuerzburg University level one trauma centre, mobile whole-body multislice computed tomography (MSCT) is used as the primary diagnostic tool in multiple trauma patients. A conventional X-ray unit is not available directly in the resuscitation room of the trauma suite. Three cases are reported to discuss whether state-of-the-art trauma management can be done without conventional radiography. METHODS: In each of the three cases reported here, an emergency situation has occurred in which the emergency diagnosis of the chest with the CT-scan was found to be difficult or impossible. These specific situations are described and discussed for each case and a conclusion is given at the end of this paper. RESULTS: Three scenarios were identified in which conventional radiological diagnostics seemed to be necessary in the emergency room despite the availability of the MSCT. One is the patient undergoing cardiopulmonary resuscitation, the second is the patient that deteriorates after CT-diagnostic is completed and the third is technical problems with the CT-scanner. CONCLUSION: Whole-body MSCT is not sufficient as the sole diagnostic tool in hemodynamically instable trauma patients requiring resuscitation and needs to be complemented by a conventional x-ray unit for emergency diagnosis of the chest.

Accidental Falls↗
PubMed2006

[Operative management in axillary brachial plexus blocks: comparison of ultrasound and nerve stimulation].

Given a case-by-case accounting system, the analysis of medical performance becomes increasingly important. Quality of treatment and the time effort attached play an important role. Anaesthesia procedures require a high level of quality and safety. Moreover, they are personnel intensive. In the area of regional anaesthesia, new procedures such as the use of high definition ultrasonography for nerve blocks, allow a possible time gain as well as improved quality. The aim of this investigation was to analyze the impact on time and results when using ultrasonography or nerve stimulation for axillary brachial plexus blocks. Therefore, over a time period of 9 months, the ultrasound-guided plexus anaesthesia (Sono) and the neurostimulation methods (NStim) were investigated based upon the anaesthesia documentation of patients undergoing hand surgery. Only those cases were included where an axillary brachial plexus block had been performed, incomplete protocols were excluded and 1.5% mepivacaine was used as medication. Overall, a total of 130 cases fulfilled these criteria. The success rates, time consumption and timelines were evaluated. All data was stored on an Excel-sheet and statistically evaluated. The results revealed a significant increase in the success rate for the patient group where ultrasound was used (98.2% Sono vs 83.1% NStim) and the operation could begin 15 min earlier in the Sono group (5 min vs. 20 min, p<0.001). Furthermore, the duration of anaesthesia was significantly shorter (85 min vs. 120 min, p<0.001) and the necessity for post-operative observation was less (5.4% vs. 32.4%, p<0.001). The data provided in the study indicate that the use of ultrasound for the identification of the nerves can clearly improve quality and time-scales of axillary brachial plexus blocks.

Adult↗
PubMed2006

[Transesophageal echocardiography for non-cardiac surgery patients: superfluous luxury or essential diagnostic tool?].

BACKGROUND: The value of transesophageal echocardiography (TEE) in non-cardiac critically ill patients has barely been studied. MATERIALS AND METHODS: Over a period of 4 years TEE was used prospectively to evaluate patients with acute hemodynamic instability in non-cardiac critically ill patients in addition to standard care. RESULTS: A total of 363 TEE studies were performed in 339 selected patients. Volume depletion (169/47%) and regional wall motion abnormalities (97/27%) were the most frequent findings followed by global left ventricular dysfunction (79/22%). Of the TEE studies, 203 (56%) provided additional information with therapeutic relevance in 164 (45%) cases. CONCLUSIONS: Transesophageal echocardiography provides additional information in critically ill non-cardiac patients with unexplained hemodynamic instability. In the majority of cases a clinical diagnosis is confirmed or improvement of volume resuscitation and catecholamine therapy can be achieved. In the minority of patients the results of TEE lead to distinct changes in medical management. Whether this improved diagnostic accuracy favours outcome, still needs to be evaluated.

Aged↗
PubMed2006

The influence of the weather and the phase of the moon on post-operative nausea and vomiting.

BACKGROUND: Post-operative nausea and vomiting (PONV) is believed and previously reported to be influenced by the weather and the phase of the moon. We therefore determined the effects of specific and general weather patterns as well as the lunar phase on PONV in adults undergoing balanced inhalation anaesthesia. METHODS: The incidence of PONV was prospectively evaluated in 1801 patients undergoing elective surgical, urologic and head and neck procedures. Air temperature, barometric pressure, air water vapour pressure and the general weather situation were obtained from the National Weather Institute in Germany on the days of surgery. Corresponding categories of temperature, pressure, vapour pressure and their day-to-day changes, the general weather situation and the phase of the moon were used to group the patient data. The differences between the proportion of patients having PONV and the proportion predicted to have PONV according to their calculated risk were determined for each category. Further, bivariate and multivariate testing was applied. RESULTS: Within 24 h after anaesthesia, PONV occurred in 555 of the patients (31%). There was no correlation between weather conditions and PONV occurrence or between the phase of the moon and PONV occurrence. Even when corrected for the patients' risk and other potentially confounding factors in multivariate logistic regression analysis, no statistically significant impact of the hypothesized factors could be detected. CONCLUSION: These data suggest that neither the weather nor the phases of the moon have any clinically relevant effect on the incidence of PONV after general anaesthesia.

Adult↗
PubMed2005

[A factorial trial of six interventions for the prevention of postoperative nausea and vomiting].

BACKGROUND: Untreated, one third of patients who undergo surgery will have postoperative nausea and vomiting. Although many trials have been conducted, the relative benefits of prophylactic antiemetic interventions given alone or in combination remain unknown. METHODS: In a randomized, controlled trial of factorial design, 5,199 patients at high risk for postoperative nausea and vomiting were randomly assigned to 1 of 64 possible combinations of 6 prophylactic interventions: 1) 4 mg of ondansetron or no ondansetron; 2) 4 mg of dexamethasone or no dexamethasone; 3) 1.25 mg of droperidol or no droperidol; 4) propofol or a volatile anesthetic; 5) nitrogen or nitrous oxide; 6) remifentanil or fentanyl. The primary aim parameter was nausea and vomiting within 24 h after surgery, which was evaluated blindly. RESULTS: Ondansetron, dexamethasone, and droperidol each reduced the risk of postoperative nausea and vomiting by about 26%, propofol reduced the risk by 19%, and nitrogen by 12%. The risk reduction with both of these agents (i.e., total intravenous anesthesia) was thus similar to that observed with each of the antiemetics alone. All the interventions acted independently of each other and independently of the patients' baseline risk. Consequently, the relative risks associated with the combined interventions could be estimated by multiplying the relative risks associated with each intervention. However, absolute risk reduction was a critical function of patients' baseline risk. CONCLUSIONS: Because antiemetic interventions are similarly effective and act independently, the safest or least expensive should be used first. Prophylaxis is rarely warranted in low-risk patients, moderate-risk patients may benefit from a single intervention, and multiple interventions should be reserved for high-risk patients.

Analgesics, Opioid↗
PubMed2005

[The Würzburg polytrauma algorithm. Concept and first results of a sliding-gantry-based computer tomography diagnostic system].

BACKGROUND: The purpose of this study was to show the practicability of a new algorithm in the management of polytraumatized patients based on Advanced Trauma Live Support (ATLS) and using mobile whole body multislice CT (MMDCT) as the primary imaging system. PATIENTS AND METHODS: A series of 120 trauma patients referred to the Würzburg University Hospital Trauma Emergency Room were categorized into suspected polytrauma and suspected non-polytrauma groups. The polytraumatized patients were investigated using the Würzburg polytrauma-algorithm including whole body multislice CT with a 16-row-scanner. The algorithm is described. The time for the diagnostic procedure was measured and compared with data from the Trauma Registry of the German Society of Trauma Surgery. RESULTS: From 120 patients 78 (66%) underwent whole body CT. The diagnostic procedure was quick with significant advantages especially for cranial and trunk diagnostics. CONCLUSION: The Würzburg polytrauma algorithm worked well. There was excellent cooperation within the interdisciplinary leading team consisting of anaesthesiologists, surgeons, and radiologists. The principles of ATLS could be respected. Mobile whole body multislice CT was an effective tool in the diagnostic evaluation of polytrauma patients.

Algorithms↗
PubMed2005

Indirect activation of adenosine A1 receptors in cultured rat hippocampal neurons by volatile anaesthetics.

BACKGROUND AND OBJECTIVE: Volatile anaesthetics depress excitatory signal transmission by potentiating the inhibitory action of GABAA receptors and there is strong evidence that this is related with anaesthesia. Using primary hippocampal cultures we analyzed the possibility that the volatile anaesthetics enflurane and sevoflurane depress excitatory signal transmission by activation of adenosine A1 receptors. METHODS: Primary rat hippocampal cultures on 4 cm poly-L-lysine coated glass coverslips were loaded with the Ca2+-indicator fluo-3 and incorporated in a gastight, temperature-controlled perfusion chamber. The intracellular Ca2+-concentration was monitored with a confocal laser-scanning microscope (BioRad) using the 488 nm laser line of a krypton-argon laser for excitation and the Lasersharp Acquisition software for analysis. RESULTS: Continuous perfusion in Mg2+-free medium generated spontaneous synchronized calcium oscillations, which were dose dependently depressed by the volatile anaesthetics enflurane and sevoflurane (0.25-1 minimum alveolar concentration). Addition of 100 nmol of 2-chloro-N6-cyclopentyladenosine, a specific adenosine A1 receptor antagonist, partly reversed the anaesthetic-induced inhibition of the oscillation amplitude of the oscillating cells. The effect of the anaesthetics was mimicked by the addition of S-(p-nitrobenzyl)-6-thioguanosine, an adenosine transport inhibitor and by the addition of 5-amino-5-deoxyadenosine, an inhibitor of adenosine kinase. CONCLUSIONS: The volatile anaesthetics sevoflurane and enflurane activate adenosine A1 receptors in primary rat hippocampal cultures. This effect is mediated by liberation of adenosine most likely by an interaction of the volatile anaesthetics with adenosine transport or key enzymes in adenosine metabolism.

Adenosine↗
PubMed2005

[The present role of interventional lung assist (ILA) in critical care medicine].

The development of low resistance oxygenators widens the therapeutic options for patients with acute respiratory failure (ARDS). Pumpless arteriovenous interventional lung assist systems (ILA) can be used in a subgroup of patients with ARDS. ILA might be indicated in earlier stages of ARDS following a multimodal treatment approach.

Adult↗
PubMed2005

Ultrasound-guided anaesthesia of the axillary brachial plexus: efficacy of multiple injection approach.

AIM: High resolution ultrasound is a new method for detecting anatomical structures in the axilla. The visualisation of nerves can improve the quality of nerve blocks. The aim of our study was to investigate the feasibility of hand held ultrasound to perform sonographically guided blockades of the axillary plexus. METHOD: We investigated 46 patients routinely scheduled for forearm and hand surgery (ASA physical status I-IV, age range 19 - 89 years, mean 47). The axilla was examined using a handheld ultrasound system with a 10 MHz linear array probe. The median, ulnar, radial and musculocutaneus nerve were visualised by ultrasound. Selective nerve blockade was performed under sonographic guidance. Real time monitoring of the local anaesthetic spread was performed. Time required to perform the block and onset times of anaesthesia were documented. RESULTS: Complete anaesthesia of the brachial plexus was achieved in all cases. The average time to perform the block was 5 minutes (SD 2 min). Onset time for the block was 7 minutes (SD 3 min). CONCLUSION: Performing axillary nerve blockade using ultrasound guidance provides excellent anaesthesia and fast onset times.

Adult↗
PubMed2005

Sonographic imaging of the sciatic nerve division in the popliteal fossa.

BACKGROUND: We studied the anatomy of the sciatic nerve and its division into the tibial and peroneal part using handheld ultrasound in adults. We wanted to evaluate the feasibility of ultrasound-guided identification of the sciatic nerve in the popliteal fossa and the correlation of the findings by ultrasound with patients' characteristics. METHODS: 74 volunteers were randomly selected. Using a handheld ultrasound system with a 5-10 MHz linear array probe the popliteal fossa and the back of the thigh were examined and measured. Using a caliper the distance of the joint line to the nerve division was measured. The sciatic nerve and its division were depicted by ultrasound. RESULTS: We could depict the sciatic nerve in all volunteers and its division in 53 of 74 (72%) volunteers. The position of nerve division showed large anatomic variation. A significant correlation between the width of the knee-joint line and the depth of the nerve division could be demonstrated. We conclude that handheld ultrasound is able to depict the sciatic nerves division. To block the nerve by one injection a more proximal access or visualization by mobile ultrasound is recommended. In addition the surrounding anatomic structures can be depicted as well.

Adolescent↗