Effect of warm-up exercise on exercise-induced bronchoconstriction.

PURPOSE: Exercise-induced bronchoconstriction (EIB) occurs when vigorous exercise induces bronchoconstriction. Preexercise warm-up routines are frequently used to elicit a refractory period and thus reduce or prevent EIB. This study aimed to conduct a systematic review to evaluate the effectiveness of preexercise routines to attenuate EIB. METHODS: A comprehensive literature search was performed, with steps taken to avoid publication and selection bias. Preexercise warm-up routines were classified into four groups: interval high intensity, continuous low intensity, continuous high intensity, and variable intensity (i.e., a combination of low intensity up to very high intensity). The EIB response was measured by the percent fall in the forced expiratory volume in 1 s (FEV1) after exercise, and the mean differences (MDs) and 95% confidence intervals (CI) are reported. RESULTS: Seven randomized studies met the inclusion criteria. The pooled results showed that high intensity (MD = -10.6%, 95% CI = -14.7% to -6.5%) and variable intensity (MD = -10.9%, 95% CI = -14.37% to -7.5%) exercise warm-up attenuated the fall in FEV1. However, continuous low-intensity warm-up (MD = -12.6%, 95% CI = -26.7% to 1.5%) and continuous high-intensity warm-up (MD = -9.8%, 95% CI = -26.0% to 6.4%) failed to result in a statistically significant reduction in bronchoconstriction. CONCLUSIONS: The most consistent and effective attenuation of EIB was observed with high-intensity interval and variable intensity preexercise warm-ups. These findings indicate that an appropriate warm-up strategy that includes at least some high-intensity exercise may be a short-term nonpharmacological strategy to reducing EIB.

Accuracy of eucapnic hyperpnea or mannitol to diagnose exercise-induced bronchoconstriction: a systematic review.

BACKGROUND: Exercise challenge testing is the typical method for diagnosing exercise induced bronchoconstriction; however, alternate tests have been developed. OBJECTIVE: The purpose of this paper was to summarize the current literature comparing eucapnic voluntary hyperpnea and mannitol with standard exercise challenge testing to determine whether either test is a suitable alternative to standard exercise testing for the diagnosis of exercise-induced bronchoconstriction. METHODS: Using valid systematic review methods, a comprehensive search strategy to avoid publication bias, we identified 10 studies that compared exercise challenge testing with either eucapnic voluntary hyperpnea or mannitol. RESULTS: For the 7 diagnostic cross-sectional studies that examined eucapnic voluntary hyperpnea, the sensitivity and specificity values were heterogeneous, ranging from 25 to 90% for sensitivity and 0 to 71% for specificity. In the 3 diagnostic cross-sectional studies that evaluated mannitol, the sensitivity and specificity ranged from 58 to 96% and 65 to 78%, respectively. For most studies, a representative spectrum of participants being tested was not used. CONCLUSION: Given the heterogeneity in sensitivity and specificity of eucapnic voluntary hyperpnea studies and the relatively small number of studies that have examined mannitol, insufficient evidence is available to conclude that either of these tests are suitable alternatives to exercise challenge testing to detect exercise-induced bronchoconstriction. Additional research is required.

Exercise-induced bronchoconstriction and asthma.

OBJECTIVES: The objectives are: (1) To assess diagnostic test characteristics of six alternative index tests compared with the selected reference standard-a standardized exercise challenge test (ECT) in patients with suspected exercise-induced bronchoconstriction or asthma (EIB/EIA); (2) to determine the efficacy of a single prophylactic dose of four pharmacologic and one nonpharmacologic interventions vs. placebo to attenuate EIB/EIA in patients with diagnosed EIB/EIA; and (3) to determine if regular daily treatment with short-acting or long-acting beta-agonists (SABA or LABA) causes patients with EIA to develop tachyphylaxis when additional prophylactic doses are used pre-exercise. DATA SOURCES: A systematic and comprehensive literature search was conducted in 14 electronic databases (Diagnosis) and the Cochrane Airways Register (Therapy). REVIEW METHODS: Study selection, quality assessment, and data extraction were conducted independently by two reviewers. The primary outcome was the maximum percent fall in the post-exercise forced expiratory volume in 1 second (percent fall FEV1). The diagnostic threshold for a positive ECT was a percent fall FEV1 of 10% or more. Sensitivity (SN) and specificity (SP) were calculated. For therapy, mean differences (MD) in the percent fall FEV1 and 95% confidence intervals (CI) (random effects model) were calculated. A positive MD indicates the intervention works better than the control. RESULTS: For the diagnostic reviews, 5,318 citations yielded 28 relevant studies; for the therapy reviews, 1,634 citations yielded 109 relevant RCTs. Diagnostic test results versus ECT: self-reported history (2 studies) SN=36-8 percent; SP=85-86 percent; sport specific challenges (5 studies) SN=0-100 percent, SP=0-100 percent; eucapnic voluntary hyperpnea (7 studies) SN=25-90 percent, SP=0-71 percent; free running asthma screening test (3 studies) SN=60-67 percent, SP=47-67 percent; mannitol (3 studies) SN=58-96 percent, SP=65-78 percent. All SN and SP calculations indicated substantial heterogeneity that could not be explained by sensitivity or subgroup analyses. Therapy results: SABA offered greater protection than mast cell stabilizers (MCS) (12 studies); MD=6.8 (95 percent CI: 4.5, 9.2) but combining them offered no additional benefit; SABA versus MCS plus SABA (5 studies) MD=1.3 (95 percent CI: -6.3, 8.9). Leukotriene receptor antagonists (LTRA), MCS, ipratropium bromide, and interval warmup routines provided statistically significant attenuation of EIA when compared with placebo; inhaled corticosteroids (ICS) and other warmup routines did not. Single-dose intervention versus placebo results are: LTRA (9 studies) MD=8.9 (95 percent CI: 6.9, 11.0); MCS (nedocromil sodium) (17 studies) MD=15.6 (95 percent CI: 13.2, 18.2); interval warmup versus no warmup (4 studies) MD=10.6 (95 percent CI: 6.5, 14.7); ICS (4 studies) MD=5.0 (95 percent CI: 0.0, 9.9); continuous low intensity warmup versus no warmup (3 studies) MD=12.6 (95 percent CI: -1.5, 26.7); continuous high intensity warmup versus no warmup (2 studies) MD=9.8 (95 percent CI: -6.4, 26.0). After daily LABA (salmeterol) use for 3 to 4 weeks (4 studies), the percent fall FEV1 following an ECT at 2 and 4 weeks was greater than at day 1 in the LABA arm indicating that tachyphylaxis to prophylactic LABA use occurred. Daily SABA use for 1 week (1 study) also indicated development of tachyphylaxis. However, both LABA and SABA continued to have an attenuating effect on EIA. CONCLUSIONS: Given the small number of studies comparing EIB/EIA diagnostic tests, the heterogeneity of the study populations, and the varied study methodologies, there is no clear evidence that any of the index tests are a suitable replacement for a standardized ECT to diagnose EIB/EIA in the general population. All bronchodilator agents and most anti-inflammatory agents when used as pretreatment are somewhat effective in attenuating the percent fall FEV1 associated with EIA.

Accuracy of Ottawa Ankle Rules to exclude fractures of the ankle and midfoot in children: a meta-analysis.

OBJECTIVES: The objectives were to conduct a systematic review to determine the diagnostic accuracy of the Ottawa Ankle Rules (OAR) to exclude ankle and midfoot fractures in children and the extent to which x-ray use could be reduced without missing significant fractures. METHODS: The authors conducted comprehensive searches of electronic databases and gray literature sources. Independent reviewers applied standard inclusion and exclusion criteria. The criterion standard diagnostic test was an ankle and/or foot x-ray or proxy measure to ensure no missed fractures. Standard 2 x 2 tables were constructed. Sensitivities and specificities were pooled using an approximation of the inverse variance; 95% confidence intervals (95% CIs) were calculated using the exact method. Likelihood ratios (LR +/-) and diagnostic odds ratios were combined under DerSimonian and Laird random effects model. RESULTS: A pooled analysis of 12 studies (N = 3,130) identified 671 fractures (prevalence = 21.4%). Ten studies reported Salter-Harris Type I (SH-I) fractures. The pooled sensitivity was 98.5% (95% CI = 97.3 to 99.2), suggesting that the OAR can be used to rule out a fracture. Four of 10 missed fractures were characterized: 1 SH-I, 1 SH-IV, and 2 "insignificant fractures" (either SH-I or avulsion fractures <3 mm). The pooled estimate for rate of x-ray reduction was 24.8% (95% CI = 23.3% to 26.3%; range = 5% to 44%). CONCLUSIONS: The OAR appear to be a reliable tool to exclude fractures in children greater than 5 years of age presenting with ankle and midfoot injuries. Employing the OAR would significantly decrease x-ray use with a low likelihood of missing a fracture.

Changing the process of care and practice in acute asthma in the emergency department: experience with an asthma care map in a regional hospital.

INTRODUCTION: Despite the frequency of acute asthma in the emergency department (ED) and the availability of guidelines, significant practice variation exists. Asthma care maps (ACMs) may standardize treatment. This study examined the use of an ACM to determine its effects on patient management in a regional hospital. METHODS: Patients aged 2 to 65 years who presented to the ED with a primary diagnosis of acute asthma were enrolled in a prospective study that took place 5 months before (pre) and 5 months after (post) ACM implementation. Research assistants using a standardized questionnaire abstracted data through direct patient interviews and then followed up at 2 weeks with a standardized telephone interview. RESULTS: Overall, 71 pre patients and 70 post patients were enrolled. Characteristics in both groups were similar. The care map was used in 100% of the cases during the post period. The mean length of stay in the ED for the pre, compared with the post period, was similar (2 h 14 min v. 2 h 25 min; p = 0.60), as were admission rates (11% v. 9%; p = 0.59). Systemic corticosteroid use was similar (62% v. 57%; p = 0.56); however, the total number of beta-agonists (2 v. 4 treatments; p = 0.002) and anticholinergics (1 v. 2 treatments; p < 0.001) administered in the ED was higher during the post period. Prescriptions for oral (73% v. 60%; p = 0.15) and inhaled (78% v. 78%; p = 0.98) corticosteroids at discharge remained the same. Relapse rates at follow-up were unchanged (29% v. 34%; p = 0.52). CONCLUSION: This study provides evidence that implementation of an ACM increased acute bronchodilator use; however, prescribing preventive medications did not increase. Further research is required to evaluate other strategies to improve asthma care by emergency physicians.

How relevant are the systematic reviews in the cochrane library to emergency medical practice?

STUDY OBJECTIVES: The Cochrane Database of Systematic Reviews (CDSR), one of the databases in the Cochrane Library, is a compilation of regularly updated systematic reviews with meta-analytic summary statistics. We conducted a study of the CDSR to evaluate the relevance of this database to emergency medical practice. METHODS: Using criteria that were determined a priori, 2 reviewers independently screened the titles of 795 completed reviews from the April 2000 CDSR for possible relevance to emergency medicine practice. Five reviewers independently ranked summaries of these reviews for degree of relevance. Agreement was measured using kappa statistics. Disagreements were resolved by consensus or adjudication. RESULTS: Screening of 795 completed reviews identified 136 (17%) as "possibly" and 151 (19%) as "likely" relevant (simple agreement, 74%; kappa=0.82). Further independent assessment indicated 95 (12%) of the 151 "likely" systematic reviews were directly relevant to emergency medicine practice, whereas 44 (6%) were indirectly relevant (simple agreement, 77%; kappa=0.45). Cochrane Review Groups producing the most emergency medicine-relevant systematic reviews included acute respiratory infections (14 [10%]), injuries (14 [10%]), pregnancy and childbirth (13 [10%]), stroke (12 [10%]), and airways (11 [8%]). In contrast, only 1 (0.1%) of the reviews produced by the Heart Review Group was considered directly relevant to emergency medicine practice. CONCLUSION: More than one third of CDSR reviews have some relevance, and 12% are directly relevant, to emergency medical practice or discharge planning. Although certain conditions are well covered, other key emergency medicine areas are not. Emergency physicians should consider the Cochrane Library an important evidence-based resource for emergency medicine therapeutic interventions and should examine ways of increasing the number of reviews relevant to emergency medicine.