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N Roewer

Publications and source records attributed to N Roewer.

At least 37 records · Page 2Linked to original sources
PubMed2004

Prediction of depth of sedation and anaesthesia by the Narcotrend EEG monitor.

BACKGROUND: The Narcotrend (Monitor Technik, Bad Bramstedt, Germany) assesses sedation by automatic classification of EEG signals, using a scale first used for visual evaluation of the EEG. Limited information is available on its value, and only a few studies of the method exist. We set out to study the performance of the Narcotrend during propofol sedation. METHODS: In 23 ASA I-II patients, aged 18-65 yr, about to have general anaesthesia, we induced anaesthesia in steps using a target-controlled infusion of propofol. After equilibration for 8 min at each predicted propofol concentration (0.5, 1.0, 2.0, 3.0 and 4.0 microg x ml(-1)), sedation was assessed clinically with the modified Observer's Assessment of Alertness/Sedation Scale and the Narcotrend stage was noted. The prediction performance of the Narcotrend was assessed with the prediction probability P(K). A P(K) value of 1.0 means an exact prediction on every occasion, while a P(K) of 0.5 is no better than a 50:50 chance of being correct. RESULTS: In 12 women and 11 men (age 42 (sd 11) yr), a total of 138 measurements were made; 129 were analysed and nine were of poor signal quality. The prediction probability for the corresponding level of sedation was P(K)=0.92 (se 0.01); for the different target concentrations of propofol it was P(K) = 0.91 (se 0.01). CONCLUSIONS: The Narcotrend can monitor sedation with propofol. Other sedatives, anaesthetics and opioids should be used to test this monitor.

Adult↗
PubMed2004

Are IL-6, IL-10 and PCT plasma concentrations reliable for outcome prediction in severe sepsis? A comparison with APACHE III and SAPS II.

OBJECTIVE: Prospective examination whether changes in interleukin (IL)-6, IL-10 or procalcitonin (PCT) concentrations correlate with poor outcome in patients with severe sepsis in comparison with APACHE III or SAPS II. METHODS: 33 patients who fulfilled the criteria for severe sepsis have been included in the study. Blood samples were collected for cytokine and PCT determinations. The Acute Physiology, Age and Chronic Health Evaluation (APACHE) III score and the Simplified Acute Physiology Score (SAPS) II were calculated for 3 consecutive days. RESULTS: 14 out of 33 patients died of multiple organ failure. The areas under the ROC-curves for APACHE III and SAPS II indicated a poor discrimination between survivors and non-survivors. Plasma PCT and IL-10 concentrations were higher in non-survivors than in survivors. IL-6 levels showed no differences between groups. The multivariate analysis of the APACHE III, SAPS II, IL-10 and PCT data showed a significant relationship between APACHE III, PCT plasma levels and outcome. CONCLUSIONS: The data suggest that non-surviving patients have higher PCT and IL-10 values. Only APACHE III score and PCT plasma levels correlated with a poor outcome. Therefore, routine measurements of plasma PCT concentrations might be helpful to improve the mortality risk prediction in patients with severe sepsis.

APACHE↗
PubMed2004

[Postoperative nausea and vomiting].

Numerous pathophysiological mechanisms are known to cause nausea or vomiting but their role for postoperative nausea and vomiting (PONV) is not quite clear. Volatile anesthetics, nitrous oxide and opioids appear to be the most important causes for PONV. Female gender, non-smoking and a history of motion sickness and PONV are the most important patient specific risk factors. With these risk factors an objective risks assessment is achievable as a good rational basis for a risk dependent antiemetic approach: When the risk is low, moderate, or high, the use of none, a single or a combination of prophylactic antiemetic interventions seems to be justified. Performing a total intravenous anesthesia (Ti.v.A) with propofol is a reasonable prophylactic approach, but does not solve the problem satisfactorily alone if the risk is very high, reducing the risk of PONV only by 30%. This is comparable to the reduction rate of antiemetics, such as serotonin antagonist, dexamethasone and droperidol. It must be stressed that metoclopramide is ineffective. Data from IMPACT indicate that prophylaxis is not very effective if the patients risk is low. At a moderate risk the use of Ti.v.A or an antiemetic is reasonable and only a (very) high risk justifies the combination of several prophylactic antiemetic interventions. For the treatment of PONV an antiemetic should be chosen which has not been used prophylactically. The necessary doses are usually a quarter of those needed for prophylaxis.

Animals↗
PubMed2004

[The "Würzburg T". A concept for optimization of early multiple trauma care in the emergency department].

INTRODUCTION: Anaesthesia management, radiological diagnostic and the concept of damage control surgery should be combined in the resuscitation room. Defined clinical targets and their realisation are a CT-scan and complete damage control surgery in the shock room. Furthermore minimised patient transfer and positioning with continuous access to the head, upper parts of the body and anaesthesia machine should be realised during diagnostic procedures. METHODS: Based on a carbon-slide fixed on a turntable and innovative alignment of diagnostic devices, a three phase treatment algorithm has been established. RESULTS: Phase A includes primary survey, anaesthetic management and ultrasound examination. Following a turn of the table conventional x-ray diagnostic is assessed in phase B. Tracks for the slide enable immediate transfer to a spiral CT-scan without additional patient positioning (phase C). Following complete CT-scan rearrangement of the table to phase A facilitates immediate damage control surgery. To accelerate device operation and treatment the integrated anaesthesia workstation is ceiling-mounted and manoeuvres close to the patient. CONCLUSIONS: This concept realizes complete diagnostic procedures and damage control surgery without time consuming patient transfer or rearrangement.

Algorithms↗
PubMed2004

[Main determinants of liver microcirculation during systemic inflammation].

More than 50% of all patients on intensive care units acquire a systemic inflammation such as systemic inflammatory response syndrome (SIRS) or sepsis. The development of hepatic microcirculatory failure with consecutive organ damage might occur during the course of the systemic inflammation. The liver microcirculation is regulated by a complex network of cellular components and specific mediators. The perfusion in liver sinusoids is regulated by the tonus of the contractile Ito cells. Nitric oxide (NO) and carbon monoxide (CO) influence each other and cause the Ito cells to dilate while endothelin results in a contraction of the Ito cells. On-going studies are investigating the role of angiotensin II, catecholamines and prostaglandins for the regulation of the hepatic microcirculatory system during systemic inflammation. Some investigations aim to determine the impact of sedatives and analgesics on the hepatic microcirculation in sepsis and SIRS. Therefore, a decisive recommendation about the choice and dosage of sedatives and analgesics for these patients is not possible. Nevertheless, ketamine, midazolam and fentanyl with their potential anti-inflammatory properties seem to be suitable for patients with systemic inflammation.

Humans↗
PubMed2004

[Pain management in shoulder surgery].

Surgical procedures in the region of the shoulder joint are among the most painful interventions in orthopedic practice. For this reason, in addition to intravenous pain therapy with opioids, blockade of the brachial plexus has become established as an effective method to provide analgesia.High-resolution ultrasound offers the possibility of performing nerve blockades under visual monitoring. Studies on interscalene blockade performed under sonographic control provide evidence for both the high efficacy and safety of the procedure. Clinically manifest signs of nerve damage have not appeared with use of this method. Smaller operations can usually be adequately managed with perioperative single-shot blockade. More extensive operations for which severe pain lasting for several days can be expected and surgical interventions involving preexistent shoulder stiffness necessitate catheterization for uninterrupted pain therapy. Successful rehabilitation after shoulder surgery requires diligent perioperative pain blockade, which can primarily be provided by interscalene plexus blockade.

Humans↗
PubMed2004

Ultrasound-guided cannulation of the internal jugular vein in critically ill patients positioned in 30 degrees dorsal elevation.

BACKGROUND AND OBJECTIVE: Catheterization of the internal jugular vein is traditionally performed with the patient lying flat or in the Trendelenburg position. This puts patients with elevated intracranial pressure at risk of cerebral herniation. The objective of this study was to assess the safety of real-time ultrasound-guided catheterization of the internal jugular vein in ventilated patients with the patient positioned in a 30 degrees head-up position. METHODS: This prospective, single-centre case series was performed in a 12-bed multi-disciplinary adult intensive care unit (ICU) in a 1500-bed university hospital. The cohort consisted of 64 ventilated ICU patients (14 female, 50 male) with a median age of 52 yr (range 18-85 yr), needing central venous cannulation for insertion of a central venous, haemodialysis or pulmonary artery catheter. The majority of patients presented with risk factors for a difficult cannulation. Catheterization was performed using real-time ultrasound guidance with all patients positioned in 30 degrees dorsal elevation. RESULTS: Ultrasound-guided cannulation of the internal jugular vein was successful in all patients. There was no evidence of air embolism. Despite a high incidence of anomalous anatomy (39%) no injury to the carotid artery occurred. Central venous access was established in less than 1 min in 75% of patients. CONCLUSION: Ultrasound-guided cannulation of the internal jugular vein in ventilated ICU patients can be performed successfully with the patient positioned in 30 degrees dorsal elevation. Potentially deleterious position changes can thus be avoided in high-risk patients.

Adolescent↗
PubMed2003

The volatile anesthetic isoflurane suppresses spontaneous calcium oscillations in vitro in rat hippocampal neurons by activation of adenosine A1 receptors.

Primary cultures of rat hippocampal neurons were loaded with the Ca(2+)-indicator fluo-3 and studied with a confocal laser microscope. In Mg(2+)-free medium the cultures showed spontaneous synchronized calcium oscillations. These oscillations derived from excitatory signal transmission by N-methyl-D-aspartate and (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid/kainate receptors and were modulated by gamma-aminobutyric acid(A) receptors. The oscillations were dose-dependently depressed by adenosine (IC50=2 microM) or by 2-chloro-N6-cyclopentyladenosine a specific adenosine A1 receptor agonist (IC50=40 nM). These effects were reverted by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), a specific adenosine A1 receptor antagonist. The volatile anesthetic isoflurane also depressed these spontaneous calcium oscillations in a dose dependent manner (IC50=0.25 MAC, Minimum Alveolar Concentration). The isoflurane-induced inhibition was partly reversed in 29-38% of the neurons by DPCPX, indicating that the anesthetic activates this receptor possibly by increasing the extracellular concentration of adenosine.

Adenosine↗
PubMed2003

[Ultrasound-guided central venous cannulation in neuropaediatric patients to avoid measures causing potential increase in brain pressure].

BACKGROUND: Certain measures such as the Trendelenburg position or an increase in intrathoracic pressure raise the chances for a successful puncture of the internal jugular vein (IJV) particularly in paediatric patients. However, these measures are contraindicated in patients with increased intracranial pressure. Therefore, in anaesthetised and ventilated neuropaediatric patients we investigated whether ultrasound-guided cannulation of the IJV can replace these measures. METHODS: In this prospective study,8 newborns, 46 infants and 66 small children were included. The cross-sectional area of the right IJV was sonographically measured in horizontal and 15 degrees Trendelenburg positions with or without PEEP 0, 5 or 10 cm H(2)O. The IJV was then punctured at the conditions of a predetermined position and PEEP combination under sonographic guidance (5-8 MHz). RESULTS: The mean cross-sectional area of the IJV was 0.3-1.6 cm(2) in the horizontal position without PEEP ( n=120) and was enlarged due to the Trendelenburg position by 24% and by 63%, when PEEP 10 cm H(2)O was added. Independent of positioning and PEEP the ultrasound-guided puncture was successful at the first attempt in 98% of cases and a second attempt had to be made in only two children. CONCLUSIONS: Under sonographic visualisation of the cross-sectional area, the IJV can easily and safely be punctured for central venous cannulation in newborn, infants and small children without measures such as the Trendelenburg position or implementation of PEEP.

Catheterization, Central Venous↗
PubMed2003

An international multicenter protocol to assess the single and combined benefits of antiemetic interventions in a controlled clinical trial of a 2x2x2x2x2x2 factorial design (IMPACT).

For various diseases clinicians have to combine different drugs or interventions when a single drug or intervention does not lead to satisfactory results. However, quantifying the relative benefit of certain drugs or interventions when given alone and in combination under controlled conditions requires a complex factorial design. This paper describes such a method applied to a large multicenter trial for the prevention of postoperative nausea and vomiting (PONV), which may be of great interest for other specialties. Approximately 28 million operations are performed annually in the United States, mainly under general anesthesia with volatile anesthetics. Unfortunately, one-third of these patients suffer from PONV. This prompted extensive research of antiemetic and anesthetic drugs, but none of the interventions appeared to satisfactorily prevent PONV. Scuderi et al. were the first to almost eliminate PONV by combining various antiemetic interventions; however, the relative benefit of each intervention remained unclear. Accordingly, we have designed a large randomized controlled trial studying six different antiemetic interventions-three involving use of various antiemetic drugs and three involving choice of anesthetic drugs-to answer the following main questions: (1) What is the relative benefit of each of the antiemetic intervention? (2) Are certain combinations of antiemetic interventions more effective than others? Using a complete factorial design this leads to 2(3)=8 antiemetic combinations, which multiply with the 2(3)=8 combinations of anesthetic drugs, leading to a total of 2(6)=64 possible combinations. The six factors are the antiemetics ondansetron (versus control), dexamethasone (versus control), droperidol (versus control), and the intravenous anesthetic propofol (versus volatile anesthetics), air (versus nitrous oxide), and remifentanil (versus fentanyl). The primary outcome is freedom from PONV within the first 24 hours after anesthesia. Eligible patients are adults scheduled for elective surgery under general anesthesia with an increased risk for PONV so that the expected incidence in the control group (with none of the six antiemetic interventions) is approximately 60%. In order to allow analyses for up to three factor interactions, a sample size was estimated to be in the range of approximately 5000 patients. To the best of our knowledge this is the first randomized controlled trial of a six-way factorial design that may serve as an example for numerous other medical specialties.

Anesthesia, Inhalation↗
PubMed2003

Treatment of hiccup during general anaesthesia or sedation: a qualitative systematic review.

BACKGROUND AND OBJECTIVE: Acute hiccup is a minor complication that can occur during sedation or general anaesthesia. The disorder can disturb the surgical field, might interfere with lung ventilation or could hamper diagnostic procedures. The objective was to perform a systematic search for interventions aimed at treating hiccup occurring during anaesthesia or sedation. METHODS: A systematic search for reports describing interventions to treat hiccup in conjunction with anaesthesia was carried out (MEDLINE, EMBASE, Cochrane-Library, manual screening of reference lists and review articles, up to December 2001). Search terms were 'hiccup', 'singultus' or 'hiccough'. RESULTS: Twenty-six reports involving approximately 581 patients focused on hiccup remedies in the anaesthesia setting. Only one report was substantiated by a randomized controlled trial. This investigated methylphenidate 10 mg intravenously in 51 patients, which did not show a beneficial effect compared with placebo. Hiccup was a self-limiting phenomenon. Case series and case reports focused on various systemically applied drugs in 12 reports, stimulating techniques (e.g. pharyngeal stimulation) in seven, topical applied remedies (e.g. intranasal ice-cold water) in four, and ventilation techniques (e.g. continuous positive pressure ventilation) in two. CONCLUSIONS: A large variety of interventions have been proposed for the treatment of hiccup during anaesthesia and sedation. However, perioperative treatment is still based on empirical findings and no treatment is 'evidence-based'. Thus, no valid recommendations for the treatment of hiccup can be derived. Uncontrolled observations are inadequate to establish treatment efficacy.

Anesthesia, General↗
PubMed2003

Effects of intra-abdominal CO2-insufflation on normal and impaired myocardial function: an experimental study.

BACKGROUND: Intra-abdominal pressure (IAP) elevation during CO2-pneumoperitoneum increases cardiac afterload and may enhance dysfunction of the already compromised heart. This study focused on the effects of acute IAP increases on left and right ventricular loadings and contractility in the heart with impaired global function. METHODS: Impairment of myocardial function (IMF) was pharmacologically induced in 16 pigs by administration of halothane and propranolol, while baseline arterial pressure was maintained by intravenous phenylephrine. Intra-abdominal pressure was gradually increased by 10 mmHg up to 30 mmHg in the supine position (IMF group 1, n = 8) or in a head-down tilted position (IMF group 2, n = 8). In two control groups with normal myocardial function, IAP was also increased in the supine position or the head-down tilted position. Cardiac function in all groups was assessed by epicardial echocardiography, intraventricular pressure measurements and pulmonary artery catheterization. RESULTS: The increase in IAP was accompanied by a transient rise in LV end-systolic wall stress and reduced cardiac output significantly by 16-24% in all groups. In the IMF groups, LV end-diastolic transmural pressure increased by 34-60% to peak values of 24 mmHg, while cross-sectional LV end-diastolic areas remained unchanged. Increases in right ventricular end-diastolic volume and decreases in right ventricular ejection fraction as well as in cardiac output were most pronounced at IAP 20 mmHg and significantly stronger in both IMF groups than in the control groups (P < 0.001). CONCLUSION: Following the acute elevation of IAP, the right ventricular volume load shifted more extensively in the IMF groups than in the animals with normal myocardial function. Myocardial function in the impaired heart may worsen during IAP elevation due to right ventricular load alterations rather than a LV afterload increase.

Abdomen↗
PubMed2003

[Evidence-based medicine and anaesthesiology--six steps towards implementation into clinical practice].

Whenever evidence-based medicine (EbM) is mentioned among physicians, it evokes many different and contradictory reactions. On the one hand a lot of physicians have heard of this concept, but may hardly associate anything with it. On the other hand most of the physicians seem to be skeptical rather than in favour of evidence-based medicine. They seem to be concerned about restrictions in daily clinical decision-making or negative implications for the relationship between patient and physician. In this article we would like to deal with the question whether evidence-based medicine is useful for clinicians and which chances are provided for both the physicians and the patients by using it. First, the methodology and aims of evidence-based medicine are introduced. Second, by using an example of clinical anaesthesiology, we discuss the six formal steps for implementing this method. Third, important points which help to assess clinical studies are mentioned. In conclusion we would like to point out that evidence-based medicine is no entirely new concept of medicine but aims to highlight a solid and conscientious scientific basis of clinical decision-making. Thus, evidence-based medicine may act as a methodological strategy helping to clear the proceedings of decision-making and improve the provision of medical care to patients. Furthermore, it may guarantee a rapid transfer of knowledge from outcome-related research to patient care.

Anesthesiology↗
PubMed2002

[Tropisetron for prevention of postoperative nausea and vomiting: a quantitative systematic review].

OBJECTIVE: A quantitative systematic review of randomised controlled trials investigating the efficacy of tropisetron versus placebo to prevent postoperative nausea (PN) and vomiting (PV) as well as PN and/or PV (PONV). METHODS: The relevant results for the 24 h postoperative period were extracted from systematically searched studies (MEDLINE, EMBASE, Cochrane-Library, reference lists; last update December 2001). RESULTS: In 19 studies and 22 comparisons, 1,012 patients received a placebo and 1,267 patients tropisetron and the pooled analyses (2-5 mg iv) are presented. The relative risks (RR) for PN, PV and PONV with tropisetron prophylaxis were 0.72 (95%-CI: 0.62-0.83), 0.59 (95%-CI: 0.47-0.73) and 0.70 (95%-CI: 0.62-0.79), respectively. The RR for rescue treatment was 0.63 (95%-CI: 0.54-0.74). The RR in children for a variable dose of 0.1-0.2 mgxkg(-1) was 0.49 (95%-CI: 0.38-0.63), 0.49 (95%-CI: 0.38-0.63) and 0.32 (95%-CI: 0.15-0.70) for PV, PONV and rescue treatment, respectively. Restricting the analysis to a predefined control event rate of 40-80% revealed that about 6-7 patients need to be treated with tropisetron for PN to be prevented in 1 patient who would have had PN if all had received a placebo (NNT=6.7; 95%-CI: 4.8-11.1). The corresponding NNT for preventing PV and PONV was 5.0 (95%-CI: 3.6-8.3) and 4.6 (95%-CI: 3.6-6.3), respectively. CONCLUSION: Tropisetron significantly reduced the incidence of PONV. There is no clear evidence for a dose response between 2 and 5 mg iv. For children a dose of 0.1 mgxkg(-1) of body weight is effective. Sufficient data for the oral application of tropisetron are lacking.

Administration, Oral↗
PubMed2002

How to study postoperative nausea and vomiting.

Anesthesiological journals are flooded by innumerable studies of postoperative nausea and vomiting (PONV). Nevertheless, PONV remains a continuing problem with an average incidence of 20-30%. This paper should provide essential information for the design, conduct, and presentation of these studies. It should also increase comparability among future studies and help clinicians in assessing and reading the literature on PONV. First, future studies should address new and relevant questions instead of repeatedly investigating prophylactically given antiemetics whose main results are predictable (e.g. already proven by meta-analysis). Second, group comparability should be based on well-proven risk factors and a simplified risk score for predicting PONV. Endless listings of doubtful risk factors should be avoided. Third, a realistic sample size estimation should be performed, i.e. in most cases at least 100 patients per group are necessary. Fourth, nausea, vomiting and rescue medication should be recorded and reported separately with the corresponding incidences (and number of patients with these separate symptoms), and the main end-point should be PONV. The entire observation period should cover 24 h. Additional reporting of the early (0-2 h) and delayed (2-24 h) postoperative period is desirable and should consider single and cumulative incidences. Lastly, interpretation of results should take into account the study hypothesis, sources of potential bias or imprecision, and the difficulties associated with multiplicity of analysis and outcomes.

Clinical Trials as Topic↗
PubMed2002

Dimenhydrinate for prophylaxis of postoperative nausea and vomiting: a meta-analysis of randomized controlled trials.

BACKGROUND: Diphenhydramine and its theoclate salt dimenhydrinate are traditional antiemetics still in use. However, so far the quantitative effect of dimenhydrinate in the prophylaxis of postoperative nausea and vomiting (PONV) has not been evaluated systematically. METHODS: Results from randomized controlled trials investigating the efficacy of dimenhydrinate vs. a control to prevent PONV were included in a meta-analysis. Studies were systematically searched through MEDLINE, EMBASE, the Cochrane-Library, manually screening of reference lists of matching review articles and current issues of locally available peer-reviewed anesthesia journals, up to June 2001. The numbers of patients with complete absence of PONV within 6 h and within 48 h after surgery were extracted as the main end point. Pooled relative benefits (RB) and numbers-needed-to-treat (NNT) with their corresponding 95% confidence intervals (CI) were calculated using a random effects model. This quantitative systematic review was performed following the recommendations of the QUORUM statement. In all, 18 trials with 3045 patients were included in the analysis: 1658 patients received a placebo (control) and 1387 patients received dimenhydrinate. RESULTS: The RB to stay completely free of PONV was 1.2 (95% CI: 1.1-1.4) for the early period (NNT = 8; 95% CI: 5-25) and 1.5 (1.3-1.8) for the overall investigated period (NNT = 5; 95% CI: 3-9). CONCLUSION: Dimenhydrinate is a traditional and inexpensive antiemetic with an efficacy that might be considered as clinically relevant. Although in use for a long time, the dose-response, precise estimation of side-effects, optimal time of administration and the benefit of repetitive doses still remain unclear.

Adult↗