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Biomedical subjects

M R Tramèr

Publications and source records attributed to M R Tramèr.

At least 19 recordsLinked to original sources
PubMed2006

The effect of cigarette smoking on the hypnotic efficacy of propofol.

The bispectral index (BIS) was used to examine the hypnotic efficacy of propofol in 25 smokers (20 cigarettes/day for 2 years) and 24 matched non-smokers (same gender, age, height, weight). BIS was recorded at baseline, at four incremental effect-site concentrations of propofol and at loss of consciousness. Compared with non-smokers, smokers were found to have higher BIS values at baseline (mean (SD)) (97 (1) vs 98 (1)), at 0.7 microg x ml(-1) (95 (3) vs 97 (1)) and at 1.1 microg x ml(-1) (89 (6) vs 94 (4)), p = 0.0099, and they lost consciousness at higher propofol concentrations (2.0 (0.4) vs 2.4 (0.8) microg x ml(-1)), p = 0.03, and at lower BIS values (66 (10) vs 60 (10)), p = 0.04. The hypnotic efficacy of propofol is reduced when used at low effect-site concentrations in smokers. This phenomenon may have some impact on the management of smokers undergoing sedation using target controlled infusion systems.

Adult↗
PubMed2003

[Cochrane Anaesthesia Review Group and the Cochrane Library. Useful resources for anaesthetists].

The Cochrane Collaboration is an international non-profit organisation that aims to help clinicians in making well-informed decisions about health care issues. This is done through preparing, maintaining and disseminating systematic reviews on the effects of health care interventions. To facilitate this task, review groups have been established. These groups cover specific health care areas and form the organisational basis of the collaboration. They provide methodological and logistic help to the authors of the systematic reviews. The Cochrane Anaesthesia Review Group (CARG) covers anaesthesia, perioperative medicine, intensive care,pre-hospital medicine, resuscitation, and emergency medicine. Protocols and completed Cochrane reviews are published in a structured format in the electronic Cochrane Library. Beside this Cochrane database of systematic reviews, the Cochrane library contains a database with summaries of non-Cochrane systematic reviews (database of abstracts of reviews of effectiveness), and a comprehensive database with controlled clinical trials (Cochrane central register of controlled trials). Thus the Cochrane library is a useful source of information on health care interventions for anaesthetists.

Anesthesiology↗
PubMed2001

Are cannabinoids an effective and safe treatment option in the management of pain? A qualitative systematic review.

OBJECTIVE: To establish whether cannabis is an effective and safe treatment option in the management of pain. DESIGN: Systematic review of randomised controlled trials. DATA SOURCES: Electronic databases Medline, Embase, Oxford Pain Database, and Cochrane Library; references from identified papers; hand searches. STUDY SELECTION: Trials of cannabis given by any route of administration (experimental intervention) with any analgesic or placebo (control intervention) in patients with acute, chronic non-malignant, or cancer pain. Outcomes examined were pain intensity scores, pain relief scores, and adverse effects. Validity of trials was assessed independently with the Oxford score. DATA EXTRACTION: Independent data extraction; discrepancies resolved by consensus. DATA SYNTHESIS: 20 randomised controlled trials were identified, 11 of which were excluded. Of the 9 included trials (222 patients), 5 trials related to cancer pain, 2 to chronic non-malignant pain, and 2 to acute postoperative pain. No randomised controlled trials evaluated cannabis; all tested active substances were cannabinoids. Oral delta-9-tetrahydrocannabinol (THC) 5-20 mg, an oral synthetic nitrogen analogue of THC 1 mg, and intramuscular levonantradol 1.5-3 mg were about as effective as codeine 50-120 mg, and oral benzopyranoperidine 2-4 mg was less effective than codeine 60-120 mg and no better than placebo. Adverse effects, most often psychotropic, were common. CONCLUSION: Cannabinoids are no more effective than codeine in controlling pain and have depressant effects on the central nervous system that limit their use. Their widespread introduction into clinical practice for pain management is therefore undesirable. In acute postoperative pain they should not be used. Before cannabinoids can be considered for treating spasticity and neuropathic pain, further valid randomised controlled studies are needed.

Analgesics, Non-Narcotic↗
PubMed2001

Cannabinoids for control of chemotherapy induced nausea and vomiting: quantitative systematic review.

OBJECTIVE: To quantify the antiemetic efficacy and adverse effects of cannabis used for sickness induced by chemotherapy. DESIGN: Systematic review. DATA SOURCES: Systematic search (Medline, Embase, Cochrane library, bibliographies), any language, to August 2000. STUDIES: 30 randomised comparisons of cannabis with placebo or antiemetics from which dichotomous data on efficacy and harm were available (1366 patients). Oral nabilone, oral dronabinol (tetrahydrocannabinol), and intramuscular levonantradol were tested. No cannabis was smoked. Follow up lasted 24 hours. RESULTS: Cannabinoids were more effective antiemetics than prochlorperazine, metoclopramide, chlorpromazine, thiethylperazine, haloperidol, domperidone, or alizapride: relative risk 1.38 (95% confidence interval 1.18 to 1.62), number needed to treat 6 for complete control of nausea; 1.28 (1.08 to 1.51), NNT 8 for complete control of vomiting. Cannabinoids were not more effective in patients receiving very low or very high emetogenic chemotherapy. In crossover trials, patients preferred cannabinoids for future chemotherapy cycles: 2.39 (2.05 to 2.78), NNT 3. Some potentially beneficial side effects occurred more often with cannabinoids: "high" 10.6 (6.86 to 16.5), NNT 3; sedation or drowsiness 1.66 (1.46 to 1.89), NNT 5; euphoria 12.5 (3.00 to 52.1), NNT 7. Harmful side effects also occurred more often with cannabinoids: dizziness 2.97 (2.31 to 3.83), NNT 3; dysphoria or depression 8.06 (3.38 to 19.2), NNT 8; hallucinations 6.10 (2.41 to 15.4), NNT 17; paranoia 8.58 (6.38 to 11.5), NNT 20; and arterial hypotension 2.23 (1.75 to 2.83), NNT 7. Patients given cannabinoids were more likely to withdraw due to side effects 4.67 (3.07 to 7.09), NNT 11. CONCLUSIONS: In selected patients, the cannabinoids tested in these trials may be useful as mood enhancing adjuvants for controlling chemotherapy related sickness. Potentially serious adverse effects, even when taken short term orally or intramuscularly, are likely to limit their widespread use.

Antiemetics↗
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

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

Pharmacological control of opioid-induced pruritus: a quantitative systematic review of randomized trials.

BACKGROUND AND OBJECTIVE: Numerous drugs have been used to prevent or to treat opioid-induced pruritus in the surgical setting. Their relative efficacy is not well understood. METHODS: The methods employed involved the systematic search (MEDLINE, EMBASE, Cochrane library, bibliographies, without language restriction, up to June 2000) for full reports of randomized comparisons of any intervention which is thought to be anti-pruritic (active) compared with placebo or no treatment (control) in surgical (including labour) patients receiving opioids. The number of patients who had no pruritus were analysed using relative risk and number-needed-to-treat with 95% confidence interval. RESULTS: Twenty-two trials (1477 patients) were analysed. Two trials (66 patients), both with low-dose propofol, were on treatment of established pruritus; propofol had no anti-pruritic effect compared with Intralipid. In prophylaxis trials, the average incidence of pruritus with control was 59% (range, 10% to 100%). Most mu-receptor antagonists were efficacious: intravenous naloxone 0.25-2.4 microg kg-1 h-1, relative risk 2.31 (95% confidence interval, 1.5 to 3.54), number-needed-to-treat to prevent pruritus compared with control 3.5; oral naltrexone 9 mg, relative risk 2.80 (1.35-5.80), number-needed-to-treat 1.7; naltrexone 6 mg was less effective and 3 mg did not work; different intravenous and epidural nalbuphine regimens, relative risk 1.71 (1.12-2.62), number-needed-to-treat 4.2. Intravenous nalmefene 0.5 or 1 mg was not anti-pruritic. Intravenous (but not epidural) droperidol 2.5 mg was efficacious, relative risk, 1.71 (1.28-2.29), number-needed-to-treat 4.9. There was a lack of evidence for any anti-pruritic efficacy with prophylactic propofol, epidural or intrathecal epinephrine, epidural clonidine, epidural prednisone, intravenous ondansetron, or intramuscular hydroxyzine. CONCLUSION: Naloxone, naltrexone, nalbuphine and droperidol are efficacious in the prevention of opioid-induced pruritus; minimal effective doses remain unknown. There is a lack of valid data on the efficacy of interventions for the treatment of established pruritus.

Analgesics, Opioid↗
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↗