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Biomedical subjects

M B Stanbrook

Publications and source records attributed to M B Stanbrook.

8 recordsLinked to original sources
PubMed2005

Hyperbaric oxygen for carbon monoxide poisoning.

BACKGROUND: Poisoning with carbon monoxide (CO) remains an important cause of accidental and intentional injury worldwide. Several unblinded non-randomized trials have suggested that the use of hyperbaric oxygen (HBO) prevents the development of neurological sequelae. This has led to the widespread use of HBO in the management of patients with carbon monoxide poisoning. OBJECTIVES: To examine randomized trials of the effectiveness of hyperbaric oxygen (HBO) compared to normobaric oxygen (NBO) for the prevention of neurologic sequelae in patients with acute carbon monoxide poisoning. SEARCH STRATEGY: We searched MEDLINE (1966-present), EMBASE (1980-present), and the Controlled Trials Register of the Cochrane Collaboration, supplemented by a manual review of bibliographies of identified articles and discussion with recognized content experts. SELECTION CRITERIA: All randomized controlled trials involving non-pregnant adults acutely poisoned with carbon monoxide (regardless of severity), with adequate or unclear allocation concealment. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted from each trial information on: the number of randomized patients, types of participants, the dose and duration of the intervention, and the prevalence of neurologic symptoms at follow-up. MAIN RESULTS: Seven randomized controlled trials of varying quality were identified; one was excluded because it did not evaluate clinical outcomes. Of the six remaining trials, two represent incomplete publications (one interim analysis, one abstract). Of these six trials, four found no benefit of HBO for the reduction of neurologic sequelae, while two others did. Although pooled analysis does not suggest a benefit from HBOT (OR for neurological deficits 0.78, 95%CI 0.54 to 1.12, p=0.18), significant methodologic and statistical heterogeneity was apparent among the trials, and this result should be interpreted cautiously. Moreover, design or analysis flaws were evident in all trials. Importantly, the conclusions of one positive trial may have been influenced by failure to adjust for multiple hypothesis testing, while interpretation of the other positive trial is hampered by apparent changes in the primary outcome during the course of the trial. AUTHORS' CONCLUSIONS: Existing randomized trials do not establish whether the administration of HBO to patients with carbon monoxide poisoning reduces the incidence of adverse neurologic outcomes. Additional research is needed to better define the role, if any, of HBO in the treatment of patients with carbon monoxide poisoning. This research question is ideally suited to a multi-center randomized controlled trial.

Carbon Monoxide Poisoning↗
PubMed2000

Hyperbaric oxygen for carbon monoxide poisoning.

BACKGROUND: Poisoning with carbon monoxide (CO) remains an important cause of accidental and intentional injury worldwide. Several unblinded nonrandomized trials have suggested that the use of hyperbaric oxygen (HBO) prevents the development of neurological sequelae. This has led to the widespread use of HBO in the management of patients with carbon monoxide poisoning. OBJECTIVES: To assess the effectiveness of hyperbaric oxygen (HBO) compared to normobaric oxygen (NBO) for the prevention of neurologic symptoms in patients with acute carbon monoxide poisoning. SEARCH STRATEGY: We searched MEDLINE (1966-present), EMBASE (1980-present), and the Controlled Trials Register of the Cochrane Collaboration, supplemented by a manual review of bibliographies of identified articles and discussion with recognized content experts. SELECTION CRITERIA: All randomized controlled trials involving non pregnant adults acutely poisoned with carbon monoxide, regardless of severity, with adequate or unclear allocation concealment were examined. Trials with a score of 3 out of 5 or higher on the validity instrument of Jadad were included in the primary analysis. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted from each trial information on the number of randomized patients, types of participants, the dose and duration of the intervention, and the prevalence of neurologic symptoms at follow-up. A pooled odds ratio (OR) for the presence of neurologic symptoms at one month follow-up was calculated using a random effects model. MAIN RESULTS: Six randomized controlled trials were identified. The trials were of varying quality. Three trials employing different doses of NBO and HBO were included in the primary analysis. The severity of CO poisoning was inconsistent between trials. At one month follow-up after treatment, symptoms possibly related to carbon monoxide poisoning were present in 81 of 237 patients (34.2%) treated with HBO, compared with 81 of 218 patients (37.2%) treated with NBO (O.R. for benefit with HBO 0.82; 95% CI 0.41-1.66). REVIEWER'S CONCLUSIONS: There is no evidence that unselected use of HBO in the treatment of acute CO poisoning reduces the frequency of neurological symptoms at one month. However, evidence from the available randomized controlled trials is insufficient to provide clear guidelines for practice. Further research is needed to better define the role of HBO, if any, in the treatment of carbon monoxide poisoning. This research question is ideally suited to a multicentre, randomized, double-blind controlled trial.

Carbon Monoxide Poisoning↗
PubMed1999

Pulmonary embolism.

Explore the source record for details and available documents.

Blood Gas Analysis↗
PubMed1999

Bronchial hyperreactivity after lung transplantation predicts early bronchiolitis obliterans.

Nonspecific bronchial hyperreactivity (NSBHR) has been observed in patients who have undergone lung transplantation, but studies have provided conflicting reports as to the incidence and significance of this finding. To delineate more clearly the natural history of NSBHR after lung transplantation, data from 111 consecutive patients undergoing double lung transplantation between February 1988 and May 1994 were reviewed. Methacholine challenge testing was requested in conjunction with regular postoperative follow-up. Among 60 patients tested at 3 mo, 18 (30%) had a positive methacholine challenge; at 6 mo, the incidence was 14 of 59 (24%). Of 21 patients for whom complete testing was performed for 12 mo or longer, 13 (62%) had exclusively negative challenges. Patients with a positive challenge at 3 mo were significantly more likely to develop bronchiolitis obliterans syndrome (BOS) (p < 0.006). Mean time to development of BOS was 16.9 mo in the group with positive challenges versus 43.9 mo for those with negative challenges. We conclude that increased NSBHR is a common, but by no means universal, finding after lung transplantation. Furthermore, early positive methacholine challenges are associated with development of BOS. We hypothesize that NSBHR may represent an early marker of chronic rejection in these patients.

Adult↗
PubMed1995

Gas trapping as a predictor of positive methacholine challenge in patients with normal spirometry results.

Methacholine challenge studies are often conducted to diagnose asthma in patients with mild or intermittent respiratory symptoms when screening spirometry results are normal. We hypothesized that in patients with increased nonspecific bronchial hyperreactivity (NSB-HR), gas trapping might be present and that this information could be a factor in clinical decision making. To assess the relationship between gas trapping and NSBHR, we conducted a retrospective chart review of 500 patients who had undergone pulmonary function testing, including lung volume measurement and methacholine challenge. Measurements of airflow, lung volumes, and methacholine PC20 values were compiled and analyzed. FRC was determined by body plethysmography (FRCB) and by helium dilution (FRC-He). FRCB-FRC-He, RV (percent of predicted) RV/TLC, and RV/TLC (percent of predicted) were used as measures of gas trapping. RV% and RV/TLC% were the best predictors of a PC20 < or = 8 mg/mL. In the subset of 169 patients who had FEV1/FVC > or = 90% of pred, an RV/TLC% value of 125% of predicted or greater had a positive predictive value of 62.5% and a negative predictive value of 62.0%. RV/TLC% was the only measure of gas trapping that was associated with a PC20 < or = 8 mg/mL (p < 0.05). Linear regression revealed no correlation between any measure of gas trapping and quantified PC20 value (< or = 16 mg/mL). These results suggest that patients with a normal FEV1/FVC who show gas trapping have an increased likelihood of a positive methacholine challenge study. Furthermore, in these patients, RV/TLC (percent of predicted) is the best predictor of a positive methacholine challenge and this parameter may be useful in raising the clinical suspicion of asthma in the large population of patients presenting with respiratory symptoms and normal flow rates.

Adolescent↗
PubMedDate not supplied

Corticosteroid therapy for patients with acute exacerbations of chronic obstructive pulmonary disease: a systematic review.

OBJECTIVE: To determine whether systemic corticosteroids are of benefit to patients with acute exacerbations of chronic obstructive pulmonary disease (COPD). METHODS: An English-language search of MEDLINE (1966 to February 2002) and the Cochrane Library and a bibliographic review was performed to identify published clinical trials of systemic corticosteroid administration in acute exacerbations of COPD. All relevant English-language, randomized, placebo-controlled clinical trials were considered. Trials investigating the adverse effects of systemic steroids were also retrieved. Studies were assigned a quality rating according to explicit criteria. Clinically relevant end points, such as treatment failure and duration of hospital stay, were considered preferentially. To compare outcomes across all qualifying studies, we considered the difference in spirometric measures between treatment and placebo groups. Potential confounding factors and bias relating to patient selection, treatment protocols, and outcome measurement were considered independently for each study. RESULTS: Among the 8 studies that met all criteria, 5 found that significant improvement in forced expiratory volume in 1 second (>20%) was associated with steroid administration. Two studies found improvement in clinically relevant outcomes. One published study and 2 study abstracts did not find significant improvement in spirometric measures with corticosteroid administration. CONCLUSION: Short courses of systemic corticosteroids in acute exacerbations of COPD have been shown to improve spirometric outcomes (good-quality evidence) and clinical outcomes (good-quality evidence).

Acute Disease↗