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Biomedical subjects

Martin R Tramèr

Publications and source records attributed to Martin R Tramèr.

At least 19 recordsLinked to original sources
PubMed2006

Pharmacological prevention of serious anaphylactic reactions due to iodinated contrast media: systematic review.

OBJECTIVE: To review the efficacy of pharmacological prevention of serious reactions to iodinated contrast media. DESIGN: Systematic review. DATA SOURCES: Systematic search (multiple databases, bibliographies, all languages, to October 2005) for randomised comparisons of pretreatment with placebo or no treatment (control) in patients receiving iodinated contrast media. Review methods Trial quality was assessed by all investigators. Information on trial design, population, interventions, and outcomes was abstracted by one investigator and cross checked by the others. Data were combined by using Peto odds ratios with 95% confidence intervals. RESULTS: Nine trials (1975-96, 10 011 adults) tested H1 antihistamines, corticosteroids, and an H1-H2 combination. No trial included exclusively patients with a history of allergic reactions. Many outcomes were not allergy related, and only a few were potentially life threatening. No reports on death, cardiopulmonary resuscitation, irreversible neurological deficit, or prolonged hospital stays were found. In two trials, 3/778 (0.4%) patients who received oral methylprednisolone 2x32 mg or intravenous prednisolone 250 mg had laryngeal oedema compared with 11/769 (1.4%) controls (odds ratio 0.31, 95% confidence interval 0.11 to 0.88). In two trials, 7/3093 (0.2%) patients who received oral methylprednisolone 2x32 mg had a composite outcome (including shock, bronchospasm, and laryngospasm) compared with 20/2178 (0.9%) controls (odds ratio 0.28, 0.13 to 0.60). In one trial, 1/196 (0.5%) patients who received intravenous clemastine 0.03 mg/kg and cimetidine 2-5 mg/kg had angio-oedema compared with 8/194 (4.1%) controls (odds ratio 0.20, 0.05 to 0.76). CONCLUSIONS: Life threatening anaphylactic reactions due to iodinated contrast media are rare. In unselected patients, the usefulness of premedication is doubtful, as a large number of patients need to receive premedication to prevent one potentially serious reaction. Data supporting the use of premedication in patients with a history of allergic reactions are lacking. Physicians who are dealing with these patients should not rely on the efficacy of premedication.

Adrenal Cortex Hormones↗
PubMed2006

Respiratory physiotherapy to prevent pulmonary complications after abdominal surgery: a systematic review.

OBJECTIVES: To examine the efficacy of respiratory physiotherapy for prevention of pulmonary complications after abdominal surgery. METHODS: We searched in databases and bibliographies for articles in all languages through November 2005. Randomized trials were included if they investigated prophylactic respiratory physiotherapy and pulmonary outcomes, and if the follow-up was at least 2 days. Efficacy data were expressed as risk differences (RDs) and number needed to treat (NNT), with 95% confidence intervals (CIs). RESULTS: Thirty-five trials tested respiratory physiotherapy treatments. Of 13 trials with a "no intervention" control group, 9 studies (n = 883) did not report on significant differences, and 4 studies (n = 528) did: in 1 study, the incidence of pneumonia was decreased from 37.3 to 13.7% with deep breathing, directed cough, and postural drainage (RD, 23.6%; 95% CI, 7 to 40%; NNT, 4.3; 95% CI, 2.5 to 14); in 1 study, the incidence of atelectasis was decreased from 39 to 15% with deep breathing and directed cough (RD, 24%; 95% CI, 5 to 43%; NNT, 4.2; 95% CI, 2.4 to 18); in 1 study, the incidence of atelectasis was decreased from 77 to 59% with deep breathing, directed cough, and postural drainage (RD, 18%; 95% CI, 5 to 31%; NNT, 5.6; 95% CI, 3.3 to 19); in 1 study, the incidence of unspecified pulmonary complications was decreased from 47.7% to 21.4 to 22.2% with intermittent positive pressure breathing, or incentive spirometry, or deep breathing with directed cough (RD, 25.5 to 26.3%; NNT, 3.8 to 3.9). Twenty-two trials (n = 2,734) compared physiotherapy treatments without no intervention control subjects; no conclusions could be drawn. CONCLUSIONS: There are only a few trials that support the usefulness of prophylactic respiratory physiotherapy. The routine use of respiratory physiotherapy after abdominal surgery does not seem to be justified.

Abdomen↗
PubMed2005

Is it always unethical to use a placebo in a clinical trial?

BACKGROUND TO THE DEBATE: Placebos are used in trials to conceal whether a treatment is being given or not and hence to control for the psychosomatic effects of offering treatment. Placebo-controlled trials are controversial. Critics of such trials argue that if a proven effective therapy exists, a placebo should not be used. But proponents argue that placebo trials are still crucial to prove the efficacy and safety of many treatments.

Ethics, Medical↗
PubMed2005

Spontaneous subarachnoid hemorrhage and serious cardiopulmonary dysfunction--a systematic review.

INTRODUCTION: : The association between the degree of neurological deficit and cardiopulmonary dysfunction in patients with spontaneous subarachnoid hemorrhage (SAH) is poorly understood. METHOD: A systematic search (MEDLINE, bibliographies, to 9.2004) was performed for prospective studies (any architecture; > or = 10 patients with SAH), reporting on neurological deficit and cardiopulmonary dysfunction. Neurological deficit was graded according to the Hunt-Hess or Botterell scores as minimal (1 or 2 points), moderate (3), or severe (4 or 5), and tested for an association with cardiopulmonary dysfunction (Chi-square test). RESULTS: Relevant data came from two randomized trials, four case control studies, and 31 uncontrolled series. In eight studies (386 patients), ECG abnormalities were found in 32% of patients with minimal, 55% with moderate, and 58% with severe neurological deficit (P < 0.0001). In six studies (135), echocardiographic abnormalities were found in 4% of patients with minimal, 30% with moderate, and 52% with severe neurological deficit (P = 0.0001). In two trials (63), creatinine phosphoskinase was increased in 18% of patients with minimal, 71% with moderate, and 100% with severe neurological deficit (P < 0.0001). In three trials (309), troponin-I was increased in 10% of patients with minimal, 20% of patients with moderate, and 46% with severe neurological deficit (P < 0.0001). In five trials (163), pulmonary edema was found in 4% of patients with minimal, 12% with moderate, and 35% with severe neurological deficit (P < 0.0001). Seventeen studies reported on mortality; 26% of the patients died, 80% of deaths were directly related to SAH. CONCLUSIONS: In patients with spontaneous SAH, cardiopulmonary dysfunction is more likely to occur with increasing neurological deficit.

Cardiovascular Diseases↗
PubMed2005

Number needed to treat (or harm).

The effect of a treatment versus controls may be expressed in relative or absolute terms. For rational decision-making, absolute measures are more meaningful. The number needed to treat, the reciprocal of the absolute risk reduction, is a powerful estimate of the effect of a treatment. It is particularly useful because it takes into account the underlying risk (what would happen without the intervention?). The number needed to treat tells us not only whether a treatment works but how well it works. Thus, it informs health care professionals about the effort needed to achieve a particular outcome. A number needed to treat should be accompanied by information about the experimental intervention, the control intervention against which the experimental intervention has been tested, the length of the observation period, the underlying risk of the study population, and an exact definition of the endpoint. A 95% confidence interval around the point estimate should be calculated. An isolated number needed to treat is rarely appropriate to summarize the usefulness of an intervention; multiple numbers needed to treat for benefit and harm are more helpful. Absolute risk reduction and number needed to treat should become standard summary estimates in randomized controlled trials.

Confidence Intervals↗
PubMed2005

Ketamine and postoperative pain--a quantitative systematic review of randomised trials.

Ketamine, an N-methyl-D-aspartate receptor antagonist, is known to be analgesic and to induce psychomimetic effects. Benefits and risks of ketamine for the control of postoperative pain are not well understood. We systematically searched for randomised comparisons of ketamine with inactive controls in surgical patients, reporting on pain outcomes, opioid sparing, and adverse effects. Data were combined using a fixed effect model. Fifty-three trials (2839 patients) from 25 countries reported on a large variety of different ketamine regimens and surgical settings. Sixteen studies tested prophylactic intravenous ketamine (median dose 0.4 mg/kg, range (0.1-1.6)) in 850 adults. Weighted mean difference (WMD) for postoperative pain intensity (0-10 cm visual analogue scale) was -0.89 cm at 6 h, -0.42 at 12 h, -0.35 at 24 h and -0.27 at 48 h. Cumulative morphine consumption at 24 h was significantly decreased with ketamine (WMD -15.7 mg). There was no difference in morphine-related adverse effects. The other 37 trials tested in adults or children, prophylactic or therapeutic ketamine orally, intramuscularly, subcutaneously, intra-articulary, caudally, epidurally, transdermally, peripherally or added to a PCA device; meta-analyses were deemed inappropriate. The highest risk of hallucinations was in awake or sedated patients receiving ketamine without benzodiazepine; compared with controls, the odds ratio (OR) was 2.32 (95%CI, 1.09-4.92), number-needed-to-harm (NNH) 21. In patients undergoing general anaesthesia, the incidence of hallucinations was low and independent of benzodiazepine premedication; OR 1.49 (95%CI 0.18-12.6), NNH 286. Despite many published randomised trials, the role of ketamine, as a component of perioperative analgesia, remains unclear.

Adult↗
PubMed2005

Prevention of succinylcholine-induced fasciculation and myalgia: a meta-analysis of randomized trials.

Fifty-two randomized trials (5,318 patients) were included in this meta-analysis. In controls, the incidence of fasciculation was 95%, and the incidence of myalgia at 24 h was 50%. Nondepolarizing muscle relaxants, lidocaine, or magnesium prevented fasciculation (number needed to treat, 1.2-2.5). Best prevention of myalgia was with nonsteroidal antiinflammatory drugs (number needed to treat, 2.5) and with rocuronium or lidocaine (number needed to treat, 3). There was a dose-dependent risk of blurred vision, diplopia, voice disorders, and difficulty in breathing and swallowing (number needed to harm, < 3.5) with muscle relaxants. There was evidence of less myalgia with 1.5 mg/kg succinylcholine (compared with 1 mg/kg). Opioids had no impact. Succinylcholine-induced fasciculation may best be prevented with muscle relaxants, lidocaine, or magnesium. Myalgia may best be prevented with muscle relaxants, lidocaine, or nonsteroidal antiinflammatory drugs. The risk of potentially serious adverse events with muscle relaxants is not negligible. Data that allow for a risk-benefit assessment are lacking for other drugs.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

Does multimodal analgesia with acetaminophen, nonsteroidal antiinflammatory drugs, or selective cyclooxygenase-2 inhibitors and patient-controlled analgesia morphine offer advantages over morphine alone? Meta-analyses of randomized trials.

The authors analyzed data from 52 randomized placebo-controlled trials (4,893 adults) testing acetaminophen, nonsteroidal antiinflammatory drugs, or selective cyclooxygenase-2 inhibitors given in conjunction with morphine after surgery. The median of the average 24-h morphine consumption in controls was 49 mg (range, 15-117 mg); it was significantly decreased with all regimens by 15-55%. There was evidence of a reduction in pain intensity at 24 h (1 cm on the 0- to 10-cm visual analog scale) only with nonsteroidal antiinflammatory drugs. Nonsteroidal antiinflammatory drugs also significantly reduced the incidence of nausea/vomiting from 28.8% to 22.0% (number needed to treat, 15) and of sedation from 15.4% to 12.7% (number needed to treat, 37) but increased the risk of severe bleeding from 0% to 1.7% (number needed to harm, 59). Selective cyclooxygenase-2 inhibitors increased the risk of renal failure in cardiac patients from 0% to 1.4% (number needed to harm, 73). A decrease in morphine consumption is not a good indicator of the usefulness of a supplemental analgesic. There is evidence that the combination of nonsteroidal antiinflammatory drugs with patient-controlled analgesia morphine offers some advantages over morphine alone.

Acetaminophen↗
PubMed2004

Analgesia and sedation in critically ill patients.

In critically ill patients, adequate analgesia and sedation increase comfort, reduce stress response and facilitate diagnostic and therapeutic procedures. Analgesia and sedation may also have a beneficial impact on morbidity, particularly by reducing pulmonary complications such as atelectasis and pneumonia, and delirium or agitation with subsequent accidental extubation. The method and depth of analgesia and sedation should be adapted to the needs of the individual patient. While evaluation of analgesia and sedation is important, technical tools for assessment are generally unreliable. Accordingly, management of these patients is best guided by simple clinical scores, though there is no consensus on how frequently pain and sedation should be evaluated. While there is some degree of consensus on what constitutes an acceptable level of pain relief, the same is not true of sedation, with the attendant risk of over-sedation. Analgesia and sedation are performed chiefly by pharmacological means. The first step includes adequate analgesia, usually with opioids. There is no evidence of a difference in efficacy between opioids as far as clinically relevant outcomes are concerned. However, there is some evidence that more sophisticated methods of opioid administration, such as patient-controlled analgesia, may improve pulmonary outcomes. In Europe, midazolam and propofol are most frequently used for sedation of the critically ill. Regular evaluation of the effect of these drugs and subsequent adaptation of dosage are more important than the choice of specific analgesics and hypnotics. Implementation of guidelines for rational analgesia and sedation would help to reduce patients' length of stay in the intensive care unit.

Algorithms↗
PubMed2004

Different patterns of duplicate publication: an analysis of articles used in systematic reviews.

CONTEXT: Duplicate publication is publication of an article that overlaps substantially with an article published elsewhere. Patterns of duplication are not well understood. OBJECTIVE: To investigate duplication patterns and propose a decision tree for classification. DATA SOURCES: We searched a comprehensive list of systematic reviews (1989 through August 15, 2002) in anesthesia and analgesia that is accessible on the Internet. We selected published full articles of duplicates that had been identified in these systematic reviews. Abstracts, letters, or book chapters were excluded. STUDY SELECTION AND DATA EXTRACTION: Authors of 56 (40%) of 141 systematic reviews acknowledged identification of duplicates. Duplication patterns were identified independently by all investigators comparing samples and outcomes of pairs of duplicates and main articles. Information on cross-reference, sponsorship, authorship, and publication characteristics was extracted from the articles. DATA SYNTHESIS: The 56 systematic reviews included 1131 main articles (129 337 subjects) and excluded 103 duplicates (12 589 subjects) that originated from 78 main articles. Sixty articles were published twice, 13 three times, 3 four times, and 2 five times. We identified 6 duplication patterns: (1A) identical samples and identical outcomes (21 pairs); (1B) same as 1A but several duplicates assembled (n = 16); (2) identical samples and different outcomes (n = 24); (3A) increasing sample and identical outcomes (n = 11); (3B) decreasing sample and identical outcomes (n = 11); (4) different samples and different outcomes (n = 20). The prevalence of covert duplicate articles (without a cross-reference to the main article) was 5.3% (65/1234). Of the duplicates, 34 (33%) were sponsored by the pharmaceutical industry, and 66 (64%) had authorship that differed partly or completely from the main article. The median journal impact factor was 1.8 (range, 0.1-29.5) for duplicates and 2.0 (range, 0.4-29.5) for main articles (P =.13). The median annual citation rate was 1.7 (range, 0-27) for duplicates and 2.1 (range, 0-31) for main articles (P =.45). The median number of authors was 4 (range, 1-14) for duplicates and 4 (range, 1-15) for corresponding main articles (P =.02). The median delay in publication between main articles and duplicates was 1 year (range, 0-7 years). CONCLUSIONS: Duplication goes beyond simple copying. Six distinct duplication patterns were identified after comparing study samples and outcomes of duplicates and corresponding main articles. Authorship was an unreliable criterion. Duplicates were published in journals with similar impact factors and were cited as frequently as main articles.

Analgesia↗
PubMed2004

Strategies for postoperative nausea and vomiting.

Significant improvement towards a better control of postoperative nausea and vomiting have been achieved in recent years. Today, we understand better who is likely to vomit or to be nauseous after surgery. Significant amounts of the huge literature on anti-emetic interventions have been systematically reviewed, critically appraised and quantitatively synthesized. Thus, we know what anti-emetic interventions work, and how well they work, and we know their adverse effect profile. We also know which interventions have no worthwhile efficacy. A rational approach to postoperative nausea and vomiting includes three steps: identification of patients at risk, keeping the baseline risk low, and prophylactic administration of anti-emetics in those patients who are most likely to need them. For patients who are identified as high-risk patients, all measurements should be simultaneously initiated (multimodal anti-emesis).

Analgesics, Opioid↗
PubMed2004

Magnesium for the prevention and treatment of acute mountain sickness.

Magnesium is a physiological N-methyl-D-aspartate (NMDA) antagonist. The NMDA receptor may be involved in the pathogenesis of acute mountain sickness (AMS). In the present study, healthy subjects were randomized to receive either 400 mg of oral magnesium citrate (16 mmol) or matching placebo every 8 h for 5 days (prevention trial). Subjects then climbed to 4559 m in approx. 24 h and stayed there for 48 h. A Lake Louise Score <3 at any time was defined as the absence of AMS, whereas a score >6 (with ataxia, headache and nausea) was defined as a prevention failure. In a subsequent trial (treatment trial), subjects with a Lake Louise Score >6 (with ataxia, headache and/or nausea) were randomized to receive either 4 g of intravenous magnesium sulphate (16 mmol) or matching placebo. A decrease in the score >50% within 60 min was regarded as a treatment success. Dichotomous data were analysed using relative risk (RR) or odds ratio (OR), and continuous data using Student's t test or Wilcoxon's rank-sum test. In the prevention trial, data from 61 subjects (30 receiving magnesium and 31 placebo) were analysed. With oral magnesium, 20% of subjects had no AMS compared with 16.1% in the placebo group [RR (95% CI), 1.2 (0.4-3.6); where CI is confidence interval]. With magnesium, 40% were prevention failures compared with 35.5% in the placebo group [RR (95% CI), 1.13 (0.59-2.15)]. The mean time to failure and severity of AMS was similar between the two groups. With magnesium, 38.2% had loose stools compared with 11.8% in placebo group [RR (95% CI), 3.25 (1.18-8.97)]. In the treatment trial, 12 subjects received magnesium and 13 received the placebo. With intravenous magnesium, 25% were regarded as treatment successes compared with none in the placebo group [OR (95% CI), 9.71 (0.91-103.4)]. With magnesium, mean (+/- S.D.) scores decreased from 11.6 +/- 1.7 before treatment to 9.0 +/- 3.5 after treatment (P=0.009); scores remained unchanged in the placebo group. With magnesium, 75% of subjects experienced a transient flushing compared with 7.7% in the placebo group [RR (95% CI), 0.05 (0.01-0.25)]. In conclusion, oral magnesium does not prevent AMS. In subjects with established AMS, intravenous magnesium reduces the severity of symptoms to some extent, but this effect is of no clinical importance.

Acute Disease↗
PubMed2004

Effect of magnesium, high altitude and acute mountain sickness on blood flow velocity in the middle cerebral artery.

Cerebral blood flow is thought to increase at high altitude and in subjects suffering from acute mountain sickness (AMS); however, data from the literature are contentious. Blood flow velocity in the middle cerebral artery (MCAv) may be used as a proxy measure of cerebral blood flow. Using transcranial Doppler sonography, MCAv was measured during normo- and hyper-ventilation in subjects who participated in a trial that tested the effect of magnesium supplementation on the prevention of AMS. First, MCAv was recorded at 353 m (baseline). Subjects were then randomized to receive oral magnesium citrate and matching placebo. A second measurement was taken after a 24 +/- 2 h ascent from 1130 m to 4559 m (altitude I), and a third after a 20-24 h stay at 4559 m (altitude II). Using multivariate linear regression, an association was sought between MCAv and magnesium supplementation, subjects' age and gender, altitude itself, a temporary stay at altitude, and the presence of AMS (Lake Louise Score >6 with ataxia, nausea and/or headache). Subjects with AMS had additional Doppler recordings immediately before and after rescue medication (oxygen, dexamethasone and acetazolamide). Forty-seven subjects had measurements at baseline, 39 (21 receiving magnesium and 18 placebo) at altitude I and 26 (13 receiving magnesium and 13 placebo) at altitude II. During hyperventilation, MCAv decreased consistently (for each measurement, P<0.001). Magnesium significantly increased MCAv by 8.4 cm.s(-1) (95% confidence interval, 1.8-15), but did not prevent AMS. No other factors were associated with MCAv. Eleven subjects had severe AMS [median score (range), 11 (8-16)] and, after rescue medication, the median score decreased to 3 (range, 0-5; P=0.001), but MCAv remained unchanged (65 +/- 18 cm.s(-1) before compared with 67 +/- 16 cm.s(-1) after rescue medication; P=0.79). MCAv was increased in subjects who received magnesium, but was not affected by exposure to high altitude or by severe AMS.

Administration, Oral↗
PubMed2004

Is low-dose haloperidol a useful antiemetic?: A meta-analysis of published and unpublished randomized trials.

The antiemetic efficacy of haloperidol was studied using data from 15 published (1962-1988) and 8 unpublished randomized trials; 1,397 adults received haloperidol, and 1,071 were controls. Settings were postoperative nausea or vomiting (1,994 patients), gastroenterology (261), chemotherapy (189), and radiation therapy (24). The relative benefit to prevent postoperative nausea or vomiting during 24 h with 0.5-4 mg haloperidol compared with placebo was 1.26-1.51 (number needed to treat, 3.2-5.1), without evidence of dose responsiveness; 0.25 mg was not antiemetic. With 1 mg haloperidol, the relative benefit to stop postoperative nausea or vomiting during 2-4 h compared with placebo was 1.53 (95% confidence interval, 1.17-2.00; number needed to treat, 6); with 2 mg, the relative benefit was 1.73 (1.11-2.68; number needed to treat, 4). In gastroenterology, 2 mg haloperidol was more effective than 1 mg. For chemotherapy and radiation therapy, no conclusions could be drawn. With 4 mg, one patient had extrapyramidal symptoms. With 5 mg, sedation was increased, with a relative risk of 2.09 (95% confidence interval, 1.73-2.52; number needed to treat, 4.4). There were no reports on cardiac toxicity. Postoperatively and in gastroenterology, haloperidol is antiemetic, with minimal toxicity. For other clinical settings and for children, valid data are unavailable.

Antiemetics↗
PubMed2004

Colonization and bloodstream infection with single- versus multi-lumen central venous catheters: a quantitative systematic review.

There is a controversy as to whether the number of lumens in the central venous catheters may impact the incidence of catheter-related bloodstream infection. We performed a systematic search (MEDLINE, PREMEDLINE, Cochrane Library, EMBASE, BIOSIS Previews, CINAHL, HealthSTAR/Ovid healthstar, bibliographies, any language, to April, 2003) for full reports on randomized comparisons of single-lumen and multi-lumen catheters. Trials had to report on dichotomous data of catheter colonization or bloodstream infection. Meta-analyses were performed using a fixed effect model. Data were expressed as odds ratio (OR) and number-needed-to-treat (NNT) with 95% confidence interval (CI). Five randomized trials (1987-1995) with data on 255 single-lumen and 275 multi-lumen catheters were analyzed. Average insertion times were 8 to 21 days with multi-lumen catheters and 9 to 24 days with single-lumen catheters. In 4 trials, 23 of 176 (13.1%) multi-lumen and 26 of 177 (14.7%) single-lumen catheters were colonized (OR, 0.92; 95% CI, 0.49-1.72). In 5 trials, bloodstream infection occurred with 23 of 275 (8.4%) multi-lumen and with 8 of 255 (3.1%) single-lumen catheters (OR, 2.58; 95% CI, 1.24-5.37; NNT, 19; 95% CI, 11-75). For every 20 single-lumen catheters inserted, one bloodstream infection will be avoided that would have occurred had multi-lumen catheters been used. The risk of catheter colonization is not decreased. Although these conclusions are based on limited data, single-lumen catheters should be used whenever feasible.

Catheterization, Central Venous↗