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B Walder

Publications and source records attributed to B Walder.

At least 19 recordsLinked to original sources
PubMed2001

[Evidence-based medicine and the systematic review in perioperative medicine].

The aim of Evidence-based medicine (EBM) is the unbiased and systematic identification and synthesis of valid scientific data. These best-evidence data may then be used for clinical decision-making. The systematic review is the most important tool of EBM and gives a specific answer to a specific question. More than 200 systematic reviews have been published in perioperative medicine. They treat complications and risks related to anaesthesia, postoperative and labour analgesia, nausea and vomiting, regional anaesthesia, blood transfusion and fluids replacement, and resuscitation. The majority of these systematic reviews are of good quality. In the specific settings of perioperative medicine the number of systematic reviews has become so important that recommendations for evidenced-based strategies of prevention and therapy can be formulated.

Anesthesiology↗
PubMed2001

Evaluation of two processed EEG analyzers for assessment of sedation after coronary artery bypass grafting.

OBJECTIVES: Processed EEG monitoring has been suggested for sedation depth evaluation in intensive care unit (ICU) patients. The present study investigated the efficacy of two processed EEG monitors using SEF90% or SEF95% and BIS to differentiate between conscious (Ramsay score 4) and unconscious sedation (Ramsay score 6). DESIGN AND SETTING: Prospective, randomized trial in a surgical ICU of a university teaching hospital. PATIENTS: Patients recovering from elective coronary bypass grafting. INTERVENTION: One of two EEG analyzers was installed (A: Aspect A-1000 measuring SEF95% and BIS; D: Drager pEEG measuring SEF90%). At ICU admission unconscious sedation (Ramsay score 6), and at three 30-min intervals conscious sedation (Ramsay score 4) were investigated. MEASUREMENTS AND RESULTS: Fourteen patients were monitored by A and 14 by D. The interindividual variability (coefficient of variation 32-69 %) was large for all three processed EEG methods. SEF90% of analyzer D and BIS of analyzer A showed a statistically significant difference between unconscious and conscious sedation (11 +/- 3 and 17 +/- 6 Hz, p = 0.005; 74 +/- 10 and 83 +/- 10, p = 0.02). Positive and negative predictive values for SEF90% of analyzer D (0.57, 95% CI 0.34-0.77; and 0.92, 95% CI 0.64-0.99) and BIS of analyzer A (0.55, 95 % CI 0.32-0.76; and 0.87, 95 % CI 0.60-0.98) were too low for discrimination between conscious and unconscious sedation. CONCLUSIONS: The use of processed EEG monitoring cannot be recommended for assessing sedation depth after cardiac surgery.

Aged↗
PubMed2001

Efficacy and safety of patient-controlled opioid analgesia for acute postoperative pain. A quantitative systematic review.

BACKGROUND: The usefulness of intravenous patient-controlled analgesia (PCA) with opioids for postoperative analgesia is not well defined. METHODS: We systematically searched (MEDLINE, EMBASE, Cochrane Library, bibliographies, any language, to January 2000) for randomised trials comparing opioid-based PCA with the same opioid given intramuscularly, intravenously, or subcutaneously. Weighted mean differences (WMD) for continuous data, relative risks (RR) and numbers-needed-to-treat (NNT) for dichotomous data were calculated with 95% confidence intervals (CI) using fixed and random effects models. RESULTS: Data from 32 trials were analysed: 22 (1139 patients) were with morphine, five (682) with pethidine, three (184) with piritramide, one (47) with nalbuphine and one (20) with tramadol. In three morphine and one pethidine trial (352 patients), more patients preferred PCA (89.7% vs. 65.8%, RR 1.41 (95%CI 1.11 to 1.80), NNT 4.2). Combined dichotomous data on pain intensity and relief, and the need for rescue analgesics from eight morphine, one pethidine, one piritramide, and one nalbuphine trial (691 patients), were in favour of PCA (RR 1.22 (1.00 to 1.50), NNT 8). In two morphine trials (152), pulmonary complications were more frequently prevented with PCA (100% vs. 93.3%, RR 1.07 (1.01 to 1.14), NNT 15). There was equivalence for cumulative opioid consumption, pain scores, duration of hospital stay, and opioid-related adverse effects. CONCLUSION: These trials provide some evidence that in the postoperative pain setting, PCA with opioids, compared with conventional opioid treatment, improve analgesia and decrease the risk of pulmonary complications, and that patients prefer them.

Acute Disease↗
PubMed2001

The effects of two single doses of tramadol on sleep: a randomized, cross-over trial in healthy volunteers.

BACKGROUND AND AIM: The effects of analgesic drugs on sleep are poorly understood. We investigated short- and medium-term effects of tramadol on sleep structure. METHODS: Eight healthy volunteers received a placebo (predrug placebo-night), then, in a randomized, double-blind, cross-over fashion a single oral dose of tramadol 50 mg or 100 mg (drug-night), and finally, again a placebo (postdrug placebo-night). Standardized polysomnography (electroencephalogram, electro-oculogram, submental electromyogram) was continuously recorded during placebo- and drug-nights. RESULTS: During drug-nights both doses of tramadol significantly increased the duration of stage 2 sleep, and significantly decreased the duration of slow-wave sleep (stage 4). Tramadol 100 mg but not 50 mg significantly decreased the duration of paradoxical (rapid eye movement) sleep. In the placebo-night after tramadol 100 mg (but not after 50 mg) duration of stage 2 sleep was significantly shorter, and duration of stage 4 sleep was significantly longer compared with the predrug placebo-night. CONCLUSION: In healthy volunteers, a single dose of tramadol 50 mg disturbs sleep in the night of drug application. With 100 mg, sleep is disturbed in both the night of drug application and in the subsequent night.

Adult↗
PubMed2001

Examining the evidence in anesthesia literature: a critical appraisal of systematic reviews.

UNLABELLED: Systematic reviews are structured reviews that use scientific strategies to reduce bias in the collection, appraisal, and interpretation of relevant studies. We undertook a systematic review of published systematic reviews in perioperative medicine to summarize the areas currently covered by this type of literature, to evaluate the quality of systematic reviews in this field, and to assess some of the methodologic and reporting issues that are unique to systematic reviews. Computerized bibliographic databases, citation review, and hand searches were performed to identify eligible articles. Quality was assessed using the Overview Quality Assessment Questionnaire. Eight-two systematic reviews were found. Reviews in perioperative medicine tended to evaluate prophylactic or therapeutic interventions. No differences were seen in quality between reviews published in anesthesia and nonanesthesia journals. Nearly half of all systematic reviews had only minor or minimal flaws; however, methods can be improved with expanded search strategies, use of least two reviewers to assess each study, use of validated methods to evaluate quality, and assessment of potential sources of bias. IMPLICATIONS: The quality of systematic reviews relating to perioperative medicine was examined systematically and found to be similar in quality to those in other specialties. Adoption of recently published criteria on writing and methods could further improve this type of literature.

Anesthesia↗
PubMed2001

A lack of evidence of superiority of propofol versus midazolam for sedation in mechanically ventilated critically ill patients: a qualitative and quantitative systematic review.

UNLABELLED: Propofol and midazolam are often used for sedation in the intensive care unit. The aim of this systematic review was to estimate the efficacy and harm of propofol versus midazolam in mechanically ventilated patients. A systematic search (Medline, Cochrane Library, Embase, bibliographies), any language, up to June 1999 was performed for reports of randomized comparisons of propofol with midazolam. Data from 27 trials (1624 adults) were analyzed. The average duration of sedation varied between 4 and 339 h. In 10 trials, the duration of adequate sedation was longer with propofol (weighted mean difference 2.9 h; 95% confidence interval [CI], 0.2-5.6 h). In 13 trials (mostly postoperative), sedation lasted 4 to 35 h; in 9 of those, average weaning time from mechanical ventilation with propofol was 0.8-4.3 h; with midazolam it was 1.5-7.2 h (weighted mean difference 2.2 h [95% CI, 0.8 to 3.7 h]). In 8 trials, sedation lasted 54 to 339 h; there was a lack of evidence for difference in weaning times. Arterial hypotension (relative risk 2.5 [95% CI, 1.3 to 4.5]; number-needed-to-treat, 12), and hypertriglyceridemia (relative risk 12.1 [95%CI, 2.9 to 49.7]; number-needed-to-treat, 6) occurred more often with propofol. The duration of adequate sedation time is longer with propofol compared with midazolam. In postoperative patients with sedation <36 h, weaning is faster with propofol. IMPLICATIONS: The duration of adequate sedation time is longer with propofol compared with midazolam. In postoperative patients with sedation < 36 h, weaning is faster with propofol.

Critical Care↗
PubMed2001

Propofol [correction of propfol] versus methohexital for electroconvulsive therapy: a meta-analysis.

A systematic search (Medline, Cochrane library, Embase, bibliographies, to 5.2000, no language restriction) was performed for published reports of randomized comparisons of propofol and methohexital for anesthesia during electroconvulsive therapy. We analyzed 15 trials with data on 706 patients. The duration of motor seizure was shorter with propofol (range, 18-39 seconds) than with methohexital (range, 26-48 seconds, weighted mean difference 8.4 seconds [95% CI, 6.6-10.0]). With both propofol and methohexital, there was little evidence of an association between dose and duration of motor seizure (for propofol: r2 = 0.25, P = .08; for methohexital: r2 = 0.11, P = .27). Two small trials investigated clinical outcome; results were inconclusive. Data on adverse effects were sparse. Duration of seizure was not proven to be a useful measure of treatment success in the study of electroconvulsive therapy with propofol or methohexital. The impact of the technique of anesthesia on the underlying disease needs to be established.

Anesthetics, Intravenous↗
PubMed2001

Transcranial Doppler versus angiography in patients with vasospasm due to a ruptured cerebral aneurysm: A systematic review.

BACKGROUND AND PURPOSE: Transcranial Doppler (TCD) is used for diagnosis of vasospasm in patients with subarachnoid hemorrhage due to a ruptured aneurysm. Our aim was to evaluate both the accuracy of TCD compared with angiography and its usefulness as a screening method in this setting. METHODS: A search (MEDLINE, EMBASE, Cochrane Library, bibliographies, hand searching, any language, through January 31, 2001) was performed for studies comparing TCD with angiography. Data were critically appraised using a modified published 10-point score and were combined using a random-effects model. RESULTS: Twenty-six reports compared TCD with angiography. Median validity score was 4.5 (range 1 to 8). Meta-analyses could be performed with data from 7 trials. For the middle cerebral artery (5 trials, 317 tests), sensitivity was 67% (95% CI 48% to 87%), specificity was 99% (98% to 100%), positive predictive value (PPV) was 97% (95% to 98%), and negative predictive value (NPV) was 78% (65% to 91%). For the anterior cerebral artery (3 trials, 171 tests), sensitivity was 42% (11% to 72%), specificity was 76% (53% to 100%), PPV was 56% (27% to 84%), and NPV was 69% (43% to 95%). Three of these 7 studies reported on the same patients, each on another artery, and for 4, data recycling could not be disproved. Other arteries were tested in only 1 trial each. CONCLUSIONS: For the middle cerebral artery, TCD is not likely to indicate a spasm when angiography does not show one (high specificity), and TCD may be used to identify patients with a spasm (high PPV). For all other situations and arteries, there is either lack of evidence of accuracy or of any usefulness of TCD. Most of these data are of low methodological quality, bias cannot not be ruled out, and data reporting is often uncritical.

Blood Flow Velocity↗
PubMed2000

Dexamethasone for the prevention of postoperative nausea and vomiting: a quantitative systematic review.

UNLABELLED: The role of dexamethasone in the prevention of postoperative nausea and vomiting (PONV) is unclear. We reviewed efficacy and safety data of dexamethasone for prevention of PONV. A systematic search (MEDLINE, EMBASE, Cochrane Library, hand searching, bibliographies, all languages, up to April 1999) was done for full reports of randomized comparisons of dexamethasone with other antiemetics or placebo in surgical patients. Relevant end points were prevention of early PONV (0 to 6 h postoperatively), late PONV (0 to 24 h), and adverse effects. Data from 1,946 patients from 17 trials were analyzed: 598 received dexamethasone; 582 received ondansetron, granisetron, droperidol, metoclopramide, or perphenazine; 423 received a placebo; and 343 received a combination of dexamethasone with ondansetron or granisetron. With placebo, the incidence of early and late PONV was 35% and 50%, respectively. Sixteen different regimens of dexamethasone were tested, most frequently, 8 or 10 mg IV in adults, and 1 or 1.5 mg/kg IV in children. With these doses, the number needed to treat to prevent early and late vomiting compared with placebo in adults and children was 7.1 (95% CI 4.5 to 18), and 3.8 (2.9 to 5), respectively. In adults, the number needed to treat to prevent late nausea was 4.3 (2.3 to 26). The combination of dexamethasone with ondansetron or granisetron further decreased the risk of PONV; the number needed to treat to prevent late nausea and vomiting with the combined regimen compared with the 5-HT3 receptor antagonists alone was 7.7 (4.8 to 19) and 7.8 (4.1 to 66), respectively. There was a lack of data from comparisons with other antiemetics for sensible conclusions. There were no reports on dexamethasone-related adverse effects. IMPLICATIONS: When there is a high risk of postoperative nausea and vomiting, a single prophylactic dose of dexamethasone is antiemetic compared with placebo, without evidence of any clinically relevant toxicity in otherwise healthy patients. Late efficacy seems to be most pronounced. It is very likely that the best prophylaxis of postoperative nausea and vomiting currently available is achieved by combining dexamethasone with a 5-HT3 receptor antagonist. Optimal doses of this combination need to be identified.

Adult↗
PubMed2000

Effects of guidelines implementation in a surgical intensive care unit to control nighttime light and noise levels.

OBJECTIVE: Because of around-the-clock activities, environmental noise and light are among the many causes of sleep disturbance in an intensive care unit (ICU). The implementation of guidelines may potentially change behavior rules and improve sleep quality. DESIGN: A prospective interventional study, observing the effects of simple nighttime guidelines on light and noise levels in an ICU. SETTING: A modern surgical ICU, subdivided into six identical three-bed rooms. PATIENTS: Critically ill adult patients. INTERVENTION: Between two observation periods, five guidelines were implemented to decrease both light and noise during the night shift in the patient's room. MEASUREMENT: Light levels and noise levels were obtained using a luxmeter and a sound level meter [A-weighted decibels (dB) scale] and were monitored continuously from 11 pm to 5 am both before (period P1) and after (period P2) the implementation of guidelines. MAIN RESULTS: Similar patient's gravity and nursing workload scores were observed between P1 and P2. A low mean (<5 Lux) and maximal light level were measured during both P1 and P2. The implementation of guidelines lowered mean light disturbance intensity with a greater variability of light during P2. All noise levels were high and corresponded more to a quiet office for noise level equivalents and to a busy restaurant for peak noise levels during both P1 and P2. Guidelines decreased the noise level equivalent (P1, 51.3 dB; P2, 48.3 dB), peak noise level (P1, 74.9 dB; P2, 70.8 dB), and the number of acoustic identified alarms (P1, 22.1 dB; P2, 15.8 dB) during P2. CONCLUSION: The night light levels were low during both periods, and lowering the light levels induced a greater variation of light, which may impair sleep quality. All measured noise levels were high during both periods, which could contribute to sleep disturbance, and the implementation of guidelines significantly lowers some important noise levels. The background noise level was unchanged.

Adult↗
PubMed2000

Similarity and robustness of PET and SPECT binding parameters for benzodiazepine receptors.

The single photon emission computed tomography (SPECT) radiotracer [123I]iomazenil is used to assess benzodiazepine receptor binding parameters. These measurements are relative indices of benzodiazepine receptor concentration (B'max). To evaluate the ability of such indices in accurately accessing the B'max the authors compared them with absolute values of B'max, measured using positron emission tomography (PET). The authors performed SPECT, PET, and magnetic resonance imaging (MRI) studies on a group composed of seven subjects. For SPECT studies, the authors administered a single injection of [123I]iomazenil and estimated the total and specific distribution volumes (DV(T SPECT), DV(S SPECT)) and the binding potential (BP) using unconstrained (BP(SPECT)) and constrained (BP(C SPECT)) compartmental models. For PET studies, the authors used a multiinjection approach with [11C]flumazenil and unlabeled flumazenil to estimate absolute values of receptor concentration, B'max, and some other binding parameters. The authors studied the correlation of different binding parameters with B'max. To study the robustness of the binding parameter measurements at the pixel level, the authors applied a wavelet-based filter to improve signal-to-noise ratio of time-concentration curves, and the calculated kinetic parameters were used to build up parametric images. For PET data, the B'max and the DV(PET) were highly correlated (r = 0.988). This confirms that it is possible to use the DV(PET) to access benzodiazepine receptor density. For SPECT data, the correlation between DV(SPECT) estimated using a two- and three-compartment model was also high (r = 0.999). The DV(T SPECT) and BP(C SPECT) parameters estimated with a constrained three-compartment model or the DV(T''SPECT) parameter estimated with a two-compartment model were also highly correlated to the B'max parameter estimated with PET. Finally, the robustness of the binding parameters allowed the authors to build pixel-by-pixel parametric images using SPECT data.

Adult↗
PubMed2000

Successful pulmonary thromboendarterectomy in a patient with Klippel-Trenaunay syndrome.

Klippel-Trenaunay syndrome (KTS) is a congenital disorder characterized by a triad of cutaneous vascular nevi, soft tissue or bony hypertrophy, and varicose veins or venous malformations involving one or more extremities. An incidence of venous thromboembolism of up to 22% has been reported in this disorder. Also reported is the development of chronic thromboembolic pulmonary hypertension (CTEPH) and subsequent death from right ventricular failure. We report the first patient with KTS to undergo a successful pulmonary thromboendarterectomy for CTEPH.

Adult↗
PubMed1999

Crusted scabies in two immunocompromised children: successful treatment with oral ivermectin.

Two immunodeficient children, aged 4 and 12 years, with crusted scabies were successfully treated with a single oral dose of ivermectin (200 micrograms/kg). One child had been diagnosed in infancy with an undefined congenital T cell immunodeficiency and the other with chronic mucocutaneous candidiasis. Both had failed to respond to conventional topical therapy. In view of the excellent therapeutic response and absence of side-effects, ivermectin should be considered in the treatment of recalcitrant crusted scabies in children.

Administration, Oral↗
PubMed1999

Metoclopramide in the prevention of postoperative nausea and vomiting: a quantitative systematic review of randomized, placebo-controlled studies.

Metoclopramide has been used for almost 40 yr to prevent postoperative nausea and vomiting (PONV). We have reviewed the efficacy and safety of metoclopramide for the prevention of PONV. A systematic search (MEDLINE, EMBASE, manufacturers' databases, hand searching, bibliographies, all languages, up to June 1998) was performed for full reports of randomized comparisons of metoclopramide with placebo in surgical patients. Relevant end-points were prevention of early PONV (within 6 h after operation), late PONV (48 h) and adverse effects. Combined data were analysed using relative benefit/risk and number-needed-to-treat/harm. In 66 studies, 3260 patients received 18 different regimens of metoclopramide, and 3006 controls received placebo or no treatment. There was no evidence of dose-responsiveness with oral, i.m., intranasal or i.v. metoclopramide in children and adults. In adults, the best documented regimen was 10 mg i.v. There was no significant anti-nausea effect. The numbers-needed-to-treat to prevent early and late vomiting were 9.1 (95% confidence intervals 5.5-27) and 10 (6-41), respectively. In children, the best documented regimen was 0.25 mg kg-1 i.v. The number-needed-to-treat to prevent early vomiting was 5.8 (3.9-11). There was no significant late anti-vomiting effect. Minor drug-related adverse effects (sedation, dizziness, drowsiness) were not significantly associated with metoclopramide. There was one adult who experienced extrapyramidal symptoms with metoclopramide.

Adult↗
PubMed1999

Efficacy and adverse effects of prophylactic antiemetics during patient-controlled analgesia therapy: a quantitative systematic review.

UNLABELLED: Nausea and vomiting are frequent adverse effects of patient-controlled analgesia (PCA) with opioids. To identify the optimal prophylactic antiemetic intervention in this setting, we performed a systematic search for randomized trials (MEDLINE, EMBASE, Cochrane library, reference lists, hand-searching, no language restriction) published up to May 1998 that compared prophylactic antiemetic interventions with placebo or no treatment in the postoperative PCA-setting with opioids. Fourteen placebo-controlled trials (1117 patients) with different regimens of droperidol, ondansetron, hyoscine TTS, tropisetron, metoclopramide, propofol, and promethazine were analyzed. One PCA was with tramadol, all others were with morphine. At 24 h, the cumulative incidence of nausea and vomiting without antiemetics was approximately 50%. Droperidol 0.017-0.17 mg/mg of morphine (0.5-11 mg/d droperidol) was statistically significantly more effective than placebo without evidence of dose-responsiveness; the number needed to treat to prevent nausea compared with placebo was 2.7 (95% confidence interval 1.8-5.2), and that to prevent vomiting was 3.1 (2.3-4.8). Compared with placebo, the incidence of minor adverse effects with droperidol was increased with doses >4 mg/d. IMPLICATIONS: Of 100 patients treated with droperidol added in a patient-controlled analgesia pump with morphine, 30 who would have vomited or been nauseated had they not received droperidol will not suffer these effects. There is no evidence of dose-responsiveness for efficacy with droperidol, but the risk of adverse effects is dose-dependent. There is a lack of evidence for other antiemetics.

Analgesia, Patient-Controlled↗
PubMed1998

[Halogenated anesthetic vaporizers: importance of maintenance regulations].

We report a serious dysfunction of 19 halothane vaporisers Vapor 19.3 (Dräger) which delivered a much higher concentration of agent than indicated on the dial. This inaccuracy was linked to a major corrosion of the inner layers of the vaporiser, with a deposit of zinc bromide and chloride in the bypass channel. The main cause for this dysfunction was the absence of an adequate maintenance of the vaporisers since their purchase 3 years before.

Anesthesia, Inhalation↗