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Biomedical subjects

M O Meade

Publications and source records attributed to M O Meade.

27 records · Page 2Linked to original sources
PubMed1998

An evidence-based approach to pressure- and volume-limited ventilation strategies.

In summary, based on the evidence reviewed, clinicians should continue to adopt a pressure-limited ventilation strategy for patients with acute lung injury, but combine this strategy with relatively liberal use of PEEP. Critical care clinicians can look forward to more information about the degree of hypercapnia that can be safely permitted in the full reports of the RCTs reviewed and in related critical care literature.

Acute Disease↗
PubMed1998

The timing of tracheotomy: a systematic review.

STUDY OBJECTIVE: To examine the impact of the timing of tracheotomy on the duration of mechanical ventilation, the secondary changes to the trachea, and the clinical course of critically ill patients in the ICU. DESIGN: A systematic review of the literature. METHODS: Two independent reviewers conducted a MEDLINE search for relevant literature in the form of randomized or observational controlled clinical studies. Studies were selected for review by criteria determined a priori; and the methodologic quality of selected studies was evaluated by duplicate independent review, also using criteria determined a priori. RESULTS: Five studies were identified, of which three were quasirandomized and none were blinded. Agreement between reviewers of methodologic quality was high (kappa=0.87). CONCLUSIONS: There is insufficient evidence to support that the timing of tracheotomy alters the duration of mechanical ventilation or extent of airway injury in critically ill patients.

Controlled Clinical Trials as Topic↗
PubMed1997

Selecting and appraising studies for a systematic review.

After thoroughly searching the potentially relevant literature for a systematic review, reviewers face the sequential tasks of selecting studies for inclusion and appraising these studies. Methodical, impartial, and reliable strategies are necessary for these two tasks because systematic reviews are retrospective exercises and are therefore prone to both bias and random error. To plan for study selection, reviewers begin with a focused clinical question and choose selection criteria that reflect this question. A detailed selection protocol that specifies the study designs and publication status of articles to be included is often helpful. Selection criteria are itemized on customized forms and are used to examine each potentially relevant primary study, usually by two different reviewers. In planning the critical appraisal of included studies, reviewers decide which clinical and methodologic study features require documentation. After choosing methods for evaluating study quality, reviewers construct customized appraisal forms and an explicit protocol for the actual evaluation. Some of the techniques commonly used to minimize the potential for error in study appraisal include duplicate, independent examination; blinding to study results and other identifying features of each article; and correspondence with study authors to clarify issues. Ultimately, primary studies should be selected, appraised, and reported in sufficient detail to allow readers to judge the applicability of the review to clinical practice and to clarify the strength of the inferences that can be drawn from the review.

Research Design↗
PubMed1997

How to use diagnostic test articles in the intensive care unit: diagnosing weanability using f/Vt.

Medical diagnosis involves generating a set of hypotheses and obtaining information that modifies these hypotheses. Sources of this information include the history, physical examination, and laboratory investigations, all of which function as diagnostic tests. Studies of diagnostic tests are useful when a) the population under study is representative of those to whom we would like to apply the results; b) when an independent, blind comparison is made of the test results with a reference standard; and c) when the reference standard is performed on all patients, rather than restricted to those patients with particular test results. Clinicians can use the data from such high quality studies in the form of sensitivity and specificity, as well as likelihood ratios, which indicate the direction and magnitude of the change in probability of a target condition from pretest to posttest. Study results will be more easily applicable to practice when the performance and interpretation of the test is similar in study and clinical settings. We conduct diagnostic tests primarily to improve the process of patient care and patient outcome, and test ordering behavior ideally reflects these goals.

Critical Care↗
PubMed1997

How to use articles about harm: the relationship between high tidal volumes, ventilating pressures, and ventilator-induced lung injury.

BACKGROUND: Intensivists commonly encounter patients who may be inadvertently harmed by critical care interventions. This article is designed to guide clinicians in the evaluations of an individual article assessing a question of harm, as well as the sum of multiple pieces of evidence. OBJECTIVES: To assess the vaidity of a group of articles about the relationship between high tidal volumes and ventilating pressures on ventilator-induced lung injury; to interpret the results of these studies; and to consider whether they apply in practice. DATA SOURCES: Issues of harm are sometimes measured in randomized trials, but are evaluated more often in myriad observational studies. DATA EXTRACTION: We use critical appraisal guides for experimental studies (e.g., randomized trials) and observational studies (e.g., cohort studies, case-control studies and case series) that evaluate the potentially harmful exposure of high tidal volumes and ventilating pressures. This involves assessing the validity of the research, then determining the strength of association between the putative harmful exposure and adverse outcomes. These study designs and their interpretation using relative risks and odds ratios are reviewed. Finally, the relevance of this information (or lack thereof) to clinical practice needs to be determined. DATA SYNTHESIS: Examining these studies individually and in totality, there appears to be a relationship between high tidal volumes and ventilating pressures, although the strength of inference from this research is limited by design issues and sample sizes. CONCLUSIONS: Critically appraising a body of literature is more challenging than evaluating a single study, but often gives a broader view of the available evidence. Future large, rigorous, randomized trials of different approaches to mechanical ventilation will help to advance our understanding and to better inform our practice.

Clinical Trials as Topic↗
PubMed1996

How to keep up with the critical care literature and avoid being buried alive.

OBJECTIVE: To provide practical suggestions for accessing, utilizing, and storing the rapidly expanding literature on critical care. DATA SOURCES: Original research on information sources for clinicians and techniques for keeping up with the literature, found through bibliographic searches, our personal files, and consultation with critical care colleagues. DATA SYNTHESIS: Suggestions for keeping up with the critical care literature include: 1) focus the clinical question; 2) locate literature using bibliographic databases; 3) use original journal articles; 4) use systematic reviews with confidence; 5) use text-books with caution; 6) read the preappraised literature; 7) abandon advertisements; 8) throw away the throwaways; 9) teach yourself critical appraisal; 10) be wary of overinterpretation of substitute end points; 11) teach yourself basic clinical statistics; 12) engage in effective browsing; 13) store useful articles; 14) invest in informatics; and 15) implement evidence-based practice guidelines. CONCLUSION: Efficient access, appraisal, and application of the literature on intensive care are basic skills for intensivists, who have adopted a variety of resourceful and pragmatic methods for "keeping up."

Critical Care↗
PubMed1996

Strategies of invasive ventilatory support in ARDS.

Acute respiratory distress syndrome is a common cause of morbidity and mortality in intensive care units. For the most part, the mortality of this syndrome has arguably not decreased since the syndrome was originally described. One of the major reasons for this lack of reduction in mortality may be related to adherence to more traditional ventilatory strategies that have the potential to cause ventilator-induced lung injury. Ventilator strategies that attempt to limit ventilator-induced lung injury and accept permissive hypercapnia have successfully demonstrated a marked reduction in mortality in uncontrolled settings. So encouraging are these reductions that there has been a subtle shift in philosophy of mechanical ventilation toward using lung-protective ventilatory strategies at all times. With broad acceptance of this shift in philosophy, and the use of recently standardized clinical definitions for controlled studies, we optimistically anticipate improved mortality rates for acute respiratory distress syndrome.

Hemodynamics↗
PubMed1995

The aetiology, consequences and prevention of barotrauma: a critical review of the literature.

PURPOSE: To review critically the literature on pulmonary barotrauma in mechanically ventilated patients. METHODS: Data sources included MEDLINE and citation lists of relevant articles. Articles investigating the aetiology or prevention of pulmonary barotrauma were critically evaluated according to published guidelines. RESULTS: Experimental animal studies and observational clinical studies consistently demonstrate that the high airway pressures and large tidal volumes associated with conventional modes of mechanical ventilation are major contributors to lung injury. Animal studies establish the correct temporal relationship and demonstrate a biological gradient. Observational clinical studies demonstrate an increased risk of barotrauma in the setting of acute lung injury. The results of three case series and two small randomised clinical trials indicate that a pressure-limited ventilation strategy aimed to reduce barotrauma may improve outcomes in patients with acute lung injury. CONCLUSIONS: Pulmonary barotrauma is a clinically important phenomenon that may delay the healing of injured lungs and lead to the development, or the exacerbation, of ARDS. Risk factors for barotrauma include high peak airway pressures, large tidal volumes and acute lung injury. Resolution of the role for pressure-limited ventilation in ARDS prevention and treatment requires a large-scale randomised clinical trial.

Airway Resistance↗