Persistent airway obstruction after virus infection is not associated with airway inflammation

BACKGROUND: This study examined the contribution of airway inflammation to the delayed lung function recovery that occurs in some people following virus-induced asthma exacerbations. METHODS: Subjects (n = 40) were recruited at hospital admission for acute asthma exacerbation. Respiratory virus infection was diagnosed by viral nucleic acid detection and/or cell culture, using induced sputum, nasal, or throat swabs. Data collected included lung function, answers to common cold and asthma control questionnaires, and induced sputum cellular profiles. Subjects were reexamined 4 to 6 weeks postexacerbation and were compared with stable asthmatic subjects (n = 26) who had been recruited from ambulatory care clinics. RESULTS: Persistent airway obstruction, defined as lung function improvement at follow-up (ie, change in FEV1 percent predicted [Delta%FEV1]) of <15%, was observed in 10 subjects (25%). Airway recovery (Delta%FEV1, > or = 15%) was observed in the remaining subjects (30 subjects; 75%). During the acute episode, the airway-recovery group had increased total cell count (p = 0.019), increased number of neutrophils (p = 0.005), and increased percentage of neutrophils (p = 0.0043) compared to the group of stable subjects with asthma. Postexacerbation, the airway-recovery group had reduced numbers of neutrophils and an increased percentage of eosinophils. In contrast, during exacerbation, subjects with persistent airway obstruction showed no differences in inflammatory cell counts compared to stable subjects with asthma, nor did cell counts change postexacerbation. Symptoms improved in both groups postexacerbation. However, in the persistent-airway-obstruction group, asthma remained uncontrolled. CONCLUSION: Persistent airway obstruction and uncontrolled asthma are observed in some people after viral asthma exacerbations. These abnormalities are not associated with inflammatory cell influx into the airway lining fluid during the exacerbation and may reflect the involvement of noncellular elements. Further work should explore other mechanisms leading to incomplete airway recovery.     

Peak expiratory flow is not a quality indicator for spirometry: peak expiratory flow variability and FEV1 are poorly correlated in an elderly population

BACKGROUND: Peak forced expiratory flow (PEF) and FEV(1) are spirometry measures used in diagnosing and monitoring lung diseases. We tested the premise that within-test variability in PEF is associated with corresponding variability in FEV(1) during a single test session. METHODS: A total of 2,464 healthy adults from the Health, Aging, and Body Composition Study whose spirometry results met American Thoracic Society acceptability criteria were screened and analyzed. The three "best" test results (highest sum of FVC and FEV(1)) were selected for each subject. For those with acceptable spirometry results, two groups were created: group 1, normal FEV(1)/FVC ratio; group 2, reduced FEV(1)/FVC ratio. For each subject, the difference between the highest and lowest PEF (DeltaPEF) and the associated difference between the highest and lowest FEV(1) (DeltaFEV(1)) were calculated. Regression analysis was performed using the largest PEF and best FEV(1), and the percentage of DeltaPEF (%DeltaPEF) and percentage of DeltaFEV(1) (%DeltaFEV(1)) were calculated in both groups. RESULTS: Regression analysis for group 1 and group 2 showed an insignificant association between %DeltaPEF and %DeltaFEV(1) (r(2) = 0.0001, p = 0.59, and r(2) = 0.040, p = 0.15, respectively). For both groups, a 29% DeltaPEF was associated with a 1% DeltaFEV(1). CONCLUSION: Within a single spirometry test session, %DeltaPEF and %DeltaFEV(1) contain independent information. PEF has a higher degree of intrinsic variability than FEV(1). Changes in PEF do not have a significant effect on FEV(1). Spirometry maneuvers should not be excluded based on peak flow variability.     

脑钠肽与呼吸困难鉴别指数在呼吸困难鉴别诊断中的应用研究

目的探讨脑钠肽（BNP）与呼吸困难鉴别指数（DDI）在急性呼吸困难患者鉴别诊断中的应用。方法测定89例呼吸困难患者血清BNP水平;同时测定患者的氧分压（PaO2）和呼气峰值流速（PEF）,根据Rajesh等创立的公式计算DDI。利用BNP和DDI鉴别心源性和肺源性呼吸困难。结果心源性呼吸困难患者血清BNP水平显著高于肺源性呼吸困难患者与正常对照组（p﹤0.01）;肺源性呼吸困难患者DDI显著低于心源性呼吸困难患者与正常对照组（p﹤0.01）;两组患者BNP与DDI具有显著的正相关性。结论测定呼吸困难患者血清BNP水平,同时应用DDI能较准确的鉴别心源性呼吸困难和肺源性呼吸困难。     

Peak expiratory flow in healthy Turkish children

This study was conducted on 1359 healthy, non-smoking Turkish children (727M, 632F) with a mean age of 11.7 ± 3.4 (6–17) years, in order to determine the normal values of peak expiratory flow (PEF) in Turkish children and to compare various peak-flow meters (PEFMs). PEF values increased with age and height in boys and girls. The relative increase in boys was significantly higher at puberty (p < 0.01). The values of Turkish children were found to be similar to those of Europeans. The results obtained from the three PEFMs were closely correlated.     

沙丁胺醇与异丙托溴铵雾化吸入治疗喘息型慢性支气管炎30例

目的：观察沙丁胺醇、异丙托溴铵联合雾化吸入对喘息型慢性支气管炎的疗效。方法：将75例喘息型慢性支气管炎急性发作期患者随机分为单用沙丁胺醇组，异丙托溴铵组及联用沙丁胺醇，异丙托溴铵组，测量雾化前，后30minPEF值，计算PEF改善率，比较疗程前后FEV1％改善程度并作统计分析。结果：三组PEF改善率的优良率分别为28.6%,50.0%,70.0%。三组FEV1％改善率的优良率分别为47.6%,62.5%,80.0%。结论：联合用药组PEF改善率，FEV1％改善程度明显高于单用药组，且临床症状改善明显，不良反应少。     

辅舒酮吸入治疗儿童哮喘的疗效观察

目的 探讨辅舒酮吸入治疗儿童哮喘的临床疗效。方法将40例患儿(年龄4～14岁)随机分两组，每组各20例，常规组长期口服酮替芬片(1mg2次／d)，治疗组长期口服酮替芬片的基础上加用辅舒酮喷雾剂(125μg／喷)吸入治疗，为期3个月，治疗期间定期随访记录临床评分、肺功能(峰流速仪测定PEF值)。结果临床评分说明辅舒酮吸入有效，临床症状得到控制或减轻，治疗组PEF值有提高，常规组PEF值无提高。结论辅舒酮长期吸入治疗后能减轻哮喘的严重程度，使哮喘得到控制，可改善肺功能。     

Asthma Exacerbations in North American Adults: Who Are the “Frequent Fliers” in the Emergency Department?

OBJECTIVE: To characterize adult asthma patients according to frequency of emergency department (ED) visits in the past year. DESIGN: Adults presenting with acute asthma to 83 US EDs underwent structured interviews in the ED and by telephone 2 weeks later. RESULTS: The 3,151 enrolled patients were classified into four groups: those reporting no ED visits in the past year (27%), one to two visits (27%), three to five visits (25%), and six or more visits (21%). The number of ED visits (NEDV) was associated with older age, nonwhite race, lower socioeconomic status, and several markers of chronic asthma severity (all p < 0.001). NEDV was strongly associated with Medicaid insurance (17% among those with no visits, 22% with one to two visits, 30% with three to five visits, 39% with six or more visits; p < 0.001). NEDV was unrelated to gender or having a primary care provider (PCP). In a multivariate model, independent predictors of high ED use (six or more visits a year) were nonwhite race, Medicaid, other public, and no insurance, and markers of chronic asthma severity. Patients with six or more ED visits accounted for 67% of all prior ED visits in the past year. CONCLUSIONS: High NEDV is associated with characteristics that may help with identification of "frequent fliers" in the ED. A better understanding of these characteristics may advance ongoing efforts to decrease asthma health-care disparities, including differential access to primary asthma care. National guidelines recommend specific ED treatments then referral to a PCP. Although longitudinal care is surely important, attempts to reduce frequent ED asthma visits may be better directed toward more specific preventive and educational needs.     

Fade of pulmonary function during residual neuromuscular blockade

OBJECTIVES: A decrement in evoked muscle force with repetitive nerve stimulation (fade) suggests impaired neuromuscular transmission. We tested the hypothesis that fade of pulmonary function, ie, a decrease in values of FVC with the second spirometric maneuver compared to the first maneuver, occurs during impaired neuromuscular transmission. DESIGN: Prospective study. PARTICIPANTS: Six healthy male volunteers. INTERVENTIONS: A series of three consecutive spirometric maneuvers was performed every 5 min in six awake healthy volunteers before, during, and after partial paralysis evoked by rocuronium (0.01 mg/kg IV plus 2 to 8 microg/kg/min). MEASUREMENTS AND RESULTS: We measured FVC, FEV(1), forced inspiratory volume in 1 s (FIV(1)), peak expiratory flow (PEF), and peak inspiratory flow (PIF) by spirometry, and force of adductor pollicis muscle by mechanomyography (train-of-four [TOF] stimulation). A statistically significant fade (reduction of the second maneuver from the first maneuver) of FVC, FEV(1), FIV(1), PEF, and PIF was observed during neuromuscular blockade. With peak relaxation (TOF ratio, 0.5) fade amounted to medians of 10% (interquartile range [IQR], 9 to 23%), 7% (IQR, 2 to 16%), 31 (IQR, 19 to 47%), 9% (IQR, 3 to 24%), and 30% (IQR, 5 to 43%), respectively. A fade of >or= 10% was always associated with a clinically relevant (>or= 10%) FVC reduction from baseline (ie, FVC before rocuronium administration). However, FVC reduction from baseline was still present in 23% of measurements without a relevant FVC fade. CONCLUSIONS: A clinically relevant fall (fade) in FVC from the first to the second value during or after neuromuscular blockade suggests impaired pulmonary function and may be due to muscle paralysis. For this reason, the first (best) FVC value may overestimate pulmonary function and expose the patient to an unidentified risk.