Effects of the menstrual cycle on timing and depth of breathing at rest

Volume and timing components of resting ventilation were measured serially in 40 women aged 18 to 36 yr, during menstrual, follicular and luteal phases of menstrual cycle. Resting minute ventilation (VE) was significantly higher (P < 0.001) in luteal phase than in menstrual and follicular phases; in the two latter phases VE was almost equal. This increment in VE during the luteal phase was due to a significant rise (P < 0.001) in tidal volume (VT). Respiratory frequency (f) was unchanged throughout the cycle. Although there was a mean increases in inspiratory time (T1) during the luteal phase compared to the other two phases, the difference did not reach statistical significance. Duty cycle, T1/Ttot, was also unchanged throughout menstrual cycle. However, mean inspiratory flow, VT/T1, was significantly higher (P < 0.05 and P < 0.01) during luteal phase as compared to that during menstrual or follicular phases respectively. Pulmonary mechanics, as measured by forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and forced mid expiratory flow rate (FEF25%, 75%), were within normal limits and remained unaltered during the menstrual cycle. Therefore, in the absence of alteration of pulmonary mechanics, the luteal increase in ventilation and inspiratory flow suggests a possible role for progesterone in stimulating the respiratory drive, either centrally or through the peripheral chemoreceptors or by both.     

The effect of tiotropium on the pulmonary diffusing capacity

To our knowledge, there is no data on the effect of tiotropium on pulmonary gas exchange in healthy subjects. The aim of this study was to assess the effects of tiotropium on pulmonary diffusing capacity. Twenty-one healthy volunteers were enrolled for a prospective, randomized, double-blind, placebo-controlled study. Spirometric measurements, including pulmonary-diffusing capacity, were obtained before and after inhalation of drug or placebo. There was a significant decrease in forced vital capacity (FVC) and, consequently, an increase in the forced expiratory volume in one second (FEV1) to FVC ratio after placebo inhalation (p < 0.05), but no changes were found for percent-predicted FVC, FEV1, percent-predicted FEV1, percent-predicted forced expiratory flow (FEF25%-75%), percent-predicted peak expiratory flow (PEF), diffusing capacity of the lung for carbon monoxide (DLCO), single-breath alveolar volume (VA) and DLCO/VA ratio when compared with the baseline. Tiotropium inhalation caused a significant increase in FVC, percent-predicted FEV1, FEV1/FVC and percent-predicted FEF25%-75%, although the decrease in DLCO was insignificant (12.4 +/- 0.9 to 11.4 +/- 0.9). In conclusion, tiotropium does not change the pulmonary-diffusing capacity in healthy volunteers.     

Effect of oral contraceptives on respiratory function

The present study was carried out to assess the lung functions in oral contraceptive administered women. Lung function tests were carried out with Spirometer (Vitallograph Compact II). A significant increase in vital capacity (VC) was observed in these women as compared to normal control. There was also a significant decrease in forced expiratory volume in 1 sec./vital capacity (FEV1/VC%) and forced expiratory volume in 1 sec./forced vital capacity (FEV1/FVC%) among oral contraceptive administered women as compared to controls. Further, a significant increase in peak expiratory flow rate (PEF), reduction in forced expiratory flow rate (FEF75-85%) and FEF75% were observed among oral contraceptive administered women as compared to controls. The increase in VC and PEF might be due to the synthetic form of progesterone (progestins) present in oral contraceptive pills which causes hyperventilatory changes. Synthetic progesterone during luteal phase of menstrual cycle might increase the static and dynamic volumes of lung i.e. VC and PEF. But FEF75% showed a decrease which might be due to the lower neuromuscular coordination during breathing.     

沙美特罗/丙酸氟替卡松对哮喘儿童肺功能的改善及临床意义

目的:观察沙美特罗/丙酸氟替卡松对哮喘儿童肺功能改善情况。方法:采用德国Jaeger公司的MasterscreenIOS测定仪,对61例支气管哮喘患儿在沙美特罗/丙酸氟替卡松治疗前后进行通气肺功能(F-V)和脉冲振荡(IOS)检测。观察用力肺活量(FVC)、第一秒用力呼气容积(FEV1)、最大呼气流速(PEF)、呼出25%肺活量时最大呼气流量(FEF25)、呼出50%肺活量时最大呼气流量(FEF50)、呼出75%肺活量时最大呼气流量(FEF75);呼吸阻抗(Zrs)、气道总阻力(R5)、中心气道阻力(R20)、响应频率(Fres)。结果:沙美特罗/丙酸氟替卡松治疗后FVC、FEV1、PEF均明显升高(P<0.001),而Zrs、R5、R20、Fres均明显降低(P<0.05),两者检查结果均有显著统计学意义。结论:吸入沙美特罗/丙酸氟替卡松能改善哮喘儿童的肺通气功能,降低气道阻力,是治疗儿童哮喘的理想药物之一。     

小气道功能指标在儿童哮喘病情严重程度评估及临床诊断中的应用

目的 探讨小气道功能指标在儿童哮喘病情严重程度评估及临床诊断中的应用价值。方法 选取2013年5月至2016年4月于郑州市第二人民医院56例哮喘急性发作期病儿作为哮喘组,并根据哮喘急性发作严重程度分为轻度(21例)、中度(20例)和重度(15例)三个亚组,同时选取同期、年龄相仿及性别相匹配的30例因其他原因引起喘息咳嗽的慢性炎症病儿和32例入院检查健康儿童分别作为非哮喘组和对照组,收集各组儿童一般资料,采用肺功能测定系统检测各组儿童用力肺活量(FVC)、最大呼气流量(PEF)、第1秒用力呼气容积(FEV1)和FEV1/FVC比值、呼出25%肺活量时呼气流速(FEF25%)、呼出50%肺活量时呼气流速(FEF50%)、呼出75%肺活量时呼气流速(FEF75%)、最大中期呼气流速(MMEF)等指标。结果 与对照组比较,非哮喘组和哮喘组病儿FVC、FEV1、PEF、FEF25%、FEF50%、FEF75%和MMEF等指标均显著降低(P<0.05),且哮喘组病儿上述指标显著低于非哮喘组[(1.42±0.36)L比(1.85±0.47)L、(1.25±0.32)L比(1.42±0.41)L、(2.68±0.64)L比(3.25±0.77)L/s、(2.54±0.65)L/s比(3.74±0.68)L/s、(1.58±0.36)L/s比(2.24±0.71)L/s、(0.61±0.37)L/s比(1.02±0.41)L/s、(1.42±0.49)L/s比(1.89±0.68)L/s)](均P<0.05),而三组病儿FEV1/FVC指标差异无统计学意义(P>0.05)。哮喘急性发作期不同程度病儿用力呼出25%肺活量的呼气流量占预计值百分比(FEF25pred%)、用力呼出50%肺活量的呼气流量占预计值百分比(FEF50pred%)、用力呼出75%肺活量的呼气流量占预计值百分比(FEF75pred%)、最大呼气中期流量占预计值的百分比(MMEFpred%)等指标比较差异有统计学意义(P<0.05),且随着病情程度增加,病儿FEF25pred%、FEF50pred%、FEF75pred%、MMEFpred%等指标呈现明显降低趋势(P<0.05),FEF25%和FEF75%指标在不同严重程度哮喘病儿中异常率比较,差异有统计学意义(P<0.05),FEF50%和MMEF指标比较差异无统计学意义(P>0.05),其中FEF25%主要表现为轻度异常,而FEF75%主要表现为重度异常。结论 小气道功能指标在儿童哮喘病情严重程度评估及临床诊断具有重要意义,随着病情加剧,小气道功能指标明显降低,且异常率显著增加。     

Status of pulmonary function tests in adolescent females of Delhi

Progesterone is known to cause hyperventilation and hypercapnia in the luteal phase of a normal menstrual cycle. Viewing this fact lung functions were measured in 71 girls with a mean age of 14.5 years during their follicular and luteal phase of menstrual cycle. Subjects were grouped into I, II and III depending on the age range. Respiratory functions comprising of FVC, FIVC, TLC, RV/TLC, FEV1, FEV1/FVC, FRC, PEFR, FEF 25%, FEF 50%, FEF 75%, PIFR, RAW and KST respectively were performed using Spiro 232 of PK Morgan under standardized laboratory settings. The anthropometric parameters such as height, weight and arm span were also recorded. The majority of pulmonary functions reflect better values in luteal phase as compared with follicular phase however, a statistically significant higher results of FVC, FIVC, FEV1, and TLC were noticed in group I and group III. These observations suggest a possible role in increased level of progesterone in luteal phase on respiratory system.     

肺高分辨率CT马赛克样灌注与小气道功能指数的相关分析

目的探讨肺小气道病变时高分辨率CT（HRCT）所示马赛克样灌注与小气道功能指标的相关性。方法选择HRCT上显示马赛克样灌注病例80例,由3位放射诊断医师对马赛克样灌注与小气道功能指标的相关性进行分析。结果马赛克样灌注与FEF 25%呈负相关（r=-0.48,P〈0.05）,与FEV1、FEF50%无相关性（r值分别为-0.27和-0.19,P〉0.05）。而空气潴留的程度与FEF25%、FEV1呈负相关（r值分别为-0.62和-0.41,P〈0.05）,与FEF 50%无相关性（r=-0.29,P〉0.05）。结论马赛克样灌注作为小气道病变的主要征象,其与FEF 25%具有良好的相关性,而空气潴留作为小气道阻塞的直接后果,其程度与FEV1、FEF 25%具显著相关性,即使肺功能检查结果正常时,也可以辅助诊断临床可疑的小气道阻塞。     

Lung function development in Indian men and women during late adolescence and early adulthood--a longitudinal study

Lung function development was studied in a cohort of Indian men (n = 31) and women (n = 36), over a period of four years during late adolescence and early adulthood. Forced expiratory spirograms and peak expiratory flow rates were recorded at intervals of approximately two years. All volumes and flow rates were higher in men, but volume adjusted flow rates were higher in women. Forced vital capacity (FVC) forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) were significantly higher in men even after standardizing for age, height and weight. Height and PEF increased significantly in men and women over the four years. Volumes showed a greater increase whereas flow rates and volume adjusted flow rates showed a greater decrease in men. The decline in the forced expiratory flow in the middle half of the FVC (FEF 25-75%) was significantly less in women. These results suggest that although lung size is greater in men, small airway dynamics may be better in young women.     

Longitudinal study of lung function development in a cohort of Indian medical students: interaction of respiratory allergy and smoking

This study was done to identify some factors that affect the growth and development of lung function during adolescence and early adulthood. Forced expiratory spirograms and peak expiratory flow rates were obtained in a cohort of normal young men (n = 63) over a period of 4 years, at intervals of approximately 2 years. Two factors that disturbed the normal pattern of lung function development in this group were smoking and respiratory allergy. Among the smokers and the allergics the decline in the forced expiratory volume expressed as a percentage of the forced vital capacity (FEV1%), the forced expiratory flow in the middle half of the forced vital capacity (FEF25-75%) and the FEF25-75% expressed as a ratio of the forced vital capacity (FEF/FVC) was more than double that among the normal subjects. The number of smokers and of allergics increased during the course of the study from 15 to 19 and from 16 to 23 respectively. There was a significant (P less than .01) interaction between smoking and the manifestation of respiratory allergy. Among nonsmokers, the number of allergic subjects increased from 12 to 13, while among smokers it increased from 4 to 10, during the four years.     

Bronchial lability in allergic rhinitis.

The aim of this study was to assess the relationship between exercise bronchial lability and the changes in pulmonary function over a one year period in allergic rhinitis. Eighty four nonsmoking male medical students of whom twenty two were allergic rhinitics were studied. Pulmonary function status was significantly lower and exercise bronchial lability significantly higher in the allergics. Over a one year period the mean decline in the forced expiratory volume in one second (FEV1) was three times greater and in the forced expiratory flow rate in the middle half of the vital capacity (FEF 25-75%) 50% greater among the allergics. The change in FEV1 was positively related to the bronchial lability, indicating that greater bronchial lability was associated with less decline in pulmonary function in these subjects.     

Chronically inhaled salmeterol improves pulmonary function in heart failure

Inhaled beta-agonists are commonly prescribed for the symptoms of exercise intolerance in heart failure despite a paucity of data regarding their safety and efficacy. This was a prospective, randomized, double-blind, double-dummy, placebo-controlled 14-day cross-over study to determine if chronic inhaled salmeterol therapy 84 microg every 12 hours improved pulmonary function without augmentation of neurohormonal systems or ventricular ectopy in 8 symptomatic heart failure subjects with left ventricular ejection fraction (LVEF) <40% and FEV1 相似文献   

Comparison of fenoterol, isoproterenol, and isoetharine with phenylephrine aerosol in asthma

The bronchodilator effect of fenoterol hydrobromide (0.5, 1.25, and 2.5 mg) was compared with either isoproterenol (2.8 mg) or isoetharine (5 mg) with phenylephrine (1.25 mg) in a double-blind placebo-controlled study. When delivered by an intermittent positive-pressure breathing device to 24 nonsmoking young adult asthmatic subjects, fenoterol produced significant improvement in forced expiratory volume at 1 second (FEV1), in maximum midexpiratory flow (FEF25-75%), and in forced expiratory flow at 25 per cent of vital capacity (FEF25%) for 6 to 8 hours, whereas isoproterenol and isoetharine with phenylephrine produced improvement for 1 and 2 hours, respectively. The lowest dosage of fenoterol was as effective as the highest but had fewer adverse effects.     

Prediction equation for lung functions in South Indian children

Lung functions including VC, IVC, FVC, FEV0.5, FEV1, PEF, FEF0.2-1.2, FEF25-75%, FEF75-85%, PIF, FMFT, MVV(IND), peak expiratory flow at 25%, 50% and 75% of FVC, peak inspiratory flow at 75%, 50%, 25% and the ratio between different lung volumes were measured with Vitallograph Compact-II spirometer on 109 South Indian school boys in the age group of five to sixteen years. The results show an increase in "lung volumes" and "flow rates" with increase in age, height and weight. FMFT and MVV(IND) also increase with increase in anthropometric measurements. All the lung functions except FEF75-85% and the ratio between different lung volumes show significant positive correlation with age, height and weight. Regression equations were derived for predicting normal lung functions for healthy South Indian boys. Lung volumes and flow rates were lower than North Indian and foreign boys. The decrease in lung functions in South Indian boys were due to their sea level dwelling, dietary habits and comparatively lower anthropometric measurements.     

CYCLOOXYGENASE METABOLITES PLAY A DIFFERENT ROLE IN OZONE-INDUCED PULMONARY FUNCTION DECLINE IN ASTHMATICS COMPARED TO NORMALS

Indomethacin has been used to demonstrate that cyclooxygenase (COX) metabolites of arachidonic acid play a mechanistic role in ozone-induced spirometric decline in normals (Nm). Since the weight of evidence suggests that asthmatics (Asth) do not differ substantially from Nm subjects in the magnitude of their spirometric response to ozone, we sought to determine whether COX metabolites play a similar role in the asthmatic response to ozone. Thirteen (n = 13) Asth and nine (n = 9) Nm volunteers were pretreated with indomethacin or placebo (3 days, 75 mg/day), then exposed for 2 h to 400 ppb ozone or clean air while performing mild intermittent exercise (Vimin = 30 L/min.). Baseline changes in spirometry (FVC, FEV1, FEF25, FEF50, FEF60p, FEF75) and soluble markers of COX metabolism (prostaglandin [PG] F2-alpha) were measured from induced sputum samples. Results showed similar reductions in FVC (Asth = 12%, Nm = 10%) and FEV1 (Asth = 13%, Nm = 11%) in Asth and Nm following ozone. Variables representing small-airways function demonstrated the greatest ozone-induced decline in Asth (FEF75 = 25%). Indomethacin pretreatment significantly attenuated ozone-induced decreases in FVC and FEV1 in Nm, but not in Asth. Marked attenuation of ozone-induced decrements in FEF75 and FEF60p was observed in Asth but not in Nm. PGF2-alpha levels were similar in both groups prior to ozone exposure with indomethacin (Asth = 65 pg/ml, Nm = 59 pg/ml), but postexposure levels in Asth were significantly elevated (118 pg/ml) compared to Nm (54 pg/ml). We conclude that COX metabolites, such as PGF2-alpha, play an important but different role in asthmatics than normals with respect to ozone-induced pulmonary function decline. Specifically, COX metabolites contribute to restrictive-type changes in normals and obstructive-type changes in small airways in asthmatics.     

Effects of Ranitidine on pulmonary function tests of patients with chronic obstructive pulmonary disease

Since the incidence of peptic ulcer and gastroesophageal reflux (GER) is more common in patients with chronic obstructive pulmonary disease (COPD) than normal population, H(2) receptor blockers are given more extensively to COPD patients. This study evaluated the effects of Ranitidine on pulmonary function tests (PFT) of the patients having COPD and peptic ulcer or GER, and of healthy volunteers.Fifty milligrams of Ranitidine was given intravenously to 30 COPD patients and 25 healthy volunteers. PFT were done before and 15, 30, 60, 120min after Ranitidine injection. Although mean forced vital capacity (FVC), forced expiratory volume in 1s (FEV(1)) and forced midexpiratory flow rate (FEF(25-75%)) of COPD patients were found to be decreased 60 and 120min after Ranitidine injection, the decrements were statistically insignificant. The decrements in PFT of healthy volunteers were also not statistically significant.H(2) receptor blockers can be used safely for treatment of gastrointestinal disorders in COPD patients who have mild or moderate obstruction. Minimal decreases in FEV(1) and FVC due to treatment by H(2) receptor blockers may clinically worsen COPD patients who have severe obstruction.     

新复方党参片防治高原脱习服的临床疗效

目的：研究新复方党参片对高原脱习服的防治作用。方法：驻守海拔5200 m一年的男性青年官兵43人随机分为新复方党参片组（28人）和对照组（15人）,采用单盲试验法。自返回驻地（海拔1400 m）前5 d开始分别口服新复方党参片和安慰剂片,直至返回驻地的第7天停药,共服药12 d。返回驻地的第2、4、6天,按高原脱习服症状调查表随访受试者的脱习服症状并进行症状分度评分。返回驻地的第7天,检测受试者的用力肺活量（FVC）、1秒钟用力呼气量（FEV1.0）、一秒率（FEV1.0/FVC,FEV1%）、最大呼气中期流速（FEF25%-75%）、呼气峰流速（PEF）、最大通气量（MVV）、左右手交叉敲击动作频率总次数（Ttis）和数字记忆广度顺背数测验得分（Sum）。结果：与对照组比较,返回驻地的第2、4、6天,新复方党参片组高原脱习服症状显著减轻（P〈0.01）;新复方党参片组与对照组的高原脱习服症状程度分度分布不同（P〈0.01）,新复方党参片组症状较轻的（基本无反应、轻度反应）占比重较大,而对照组中症状较重的（中度反应、重度反应）占比重较大;新复方党参片组高原脱习服发生率明显降低;新复方党参片组的FVC、FEV1.0、PEF、MVV均显著升高（P〈0.05,P〈0.01）,FEV1%和FEF25%-75%无统计学差异;新复方党参片组Ttis、Ctis显著增加（P〈0.05,P〈0.01）,平均时间（Atime）显著减少（P〈0.05）,错误次数（Etis）和Sum差异不显著。结论：新复方党参片能减轻高原脱习服的程度,减轻高原脱习服的症状,降低高原脱习服发生率;并能显著改善受试者的肺通气功能和手指运动能力,具有较好的防治高原脱习服的作用。     

Cyclooxygenase metabolites play a different role in ozone-induced pulmonary function decline in asthmatics compared to normals

Indomethacin has been used to demonstrate that cyclooxygenase (COX) metabolites of arachidonic acid play a mechanistic role in ozone-induced spirometric decline in normals (Nm). Since the weight of evidence suggests that asthmatics (Asth) do not differ substantially from Nm subjects in the magnitude of their spirometric response to ozone, we sought to determine whether COX metabolites play a similar role in the asthmatic response to ozone. Thirteen (n = 13) Asth and nine (n = 9) Nm volunteers were pretreated with indomethacin or placebo (3 days, 75 mg/day), then exposed for 2 h to 400 ppb ozone or clean air while performing mild intermittent exercise (Vi(min) = 30 L/min.). Baseline changes in spirometry (FVC, FEV(1), FEF(25), FEF(50), FEF(60p), FEF(75)) and soluble markers of COX metabolism (prostaglandin [PG] F2-alpha) were measured from induced sputum samples. Results showed similar reductions in FVC (Asth = 12%, Nm = 10%) and FEV(1) (Asth = 13%, Nm = 11%) in Asth and Nm following ozone. Variables representing small-airways function demonstrated the greatest ozone-induced decline in Asth (FEF(75) = 25%). Indomethacin pretreatment significantly attenuated ozone-induced decreases in FVC and FEV(1) in Nm, but not in Asth. Marked attenuation of ozone-induced decrements in FEF(75) and FEF(60p) was observed in Asth but not in Nm. PGF2-alpha levels were similar in both groups prior to ozone exposure with indomethacin (Asth = 65 pg/ml, Nm = 59 pg/ml), but postexposure levels in Asth were significantly elevated (118 pg/ml) compared to Nm (54 pg/ml). We conclude that COX metabolites, such as PGF2-alpha, play an important but different role in asthmatics than normals with respect to ozone-induced pulmonary function decline. Specifically, COX metabolites contribute to restrictive-type changes in normals and obstructive-type changes in small airways in asthmatics.     

布地奈德气雾剂治疗儿童哮喘的效果观察

目的观察布地奈德气雾剂治疗儿童哮喘的临床效果。方法选择本院2009年1月～2012年10月收治的使用布地奈德气雾剂治疗的儿童哮喘患者100例作为观察组,另选取本院往期采用常规化痰、止咳、支气管扩张药物吸人治疗的100例儿童哮喘患者作为对照组,采用峰流速仪监测用力肺活量（FVC）,第1秒用力呼气量（FEV1）、用力呼气中期流速[FEF（25％～75％）1等指标变化情况,并观察1年内哮喘发作情况及治疗前后住院状况。结果治疗后观察组FVC、FEV1、FEF（25％～75％）等指标明显优于对照组,差异均有统计学意义（P〈0．05）;对照组总有效率为79．0％,观察组总有效牢为96．0％,差异有统计学意义（x^2=6．182,P〈0．05）。结论布地奈德气雾剂治疗儿童哮喘不良反应少,安全有效,方法简便,值得临床推广。     

Pulmonary functions in air conditioner users

Air conditioning may affect human health since it has profound effect on our environment, than just lowering temperature. The present study was planned to assess the effect of air conditioners (AC) on pulmonary functions in young healthy non-smoker males. The study group comprised of ten subjects who were using AC's in their cars for at least 1 hr daily since last 6 months. While ten subjects who did not use AC at all served as controls. The pulmonary functions were assessed using PK Morgan 232 spirometer in a closed room. The peak expiratory flow rate (PEFR) and Forced expiratory flow between 25-75% of vital capacity (FEF25-75) were significantly reduced in subjects using car AC's. Inspiratory flow rates also showed a trend towards decline in AC users but could not reach the level of significance. The lung volumes and capacities were not significantly different in the two groups except for forced expiratory volume in 0.5 sec (FEV 0.5 sec), which also decreased in AC users. The airway resistance and lung compliance did not show significant change. In the presence of normal FEV1, reduced FEF25-75% which is the flow rate over the middle half of vital capacity, is an evidence of mild airflow limitation. The result is suggestive of predisposition of AC users towards respiratory disorders in form of mild airflow restriction.     

Large and small airway responses to procaterol hydrochloride administered through different extension devices in asthmatic patients.

The effects of spacer devices on the magnitude and velocity of large and small airway bronchodilator responses in asthmatic patients who can correctly operate a metered dose inhaler (MDI) remain unclear. According to a double-blinded, randomized, crossover protocol, 14 asthmatic patients were studied on seven separate occasions. On each occasion, patients inhaled doubling methacholine concentrations until forced expiratory volume in 1 second (FEV1) had fallen by 20% of baseline. Changes in forced expiratory flow between 25% and 75% of vital capacity (FEF25-75) were also evaluated. Subsequently, patients were administered 20 or 50 micrograms of procaterol from an MDI either alone or in conjunction with a small- or large-volume spacer device. Changes in FEV1 and FEF25-75 corrected for baseline forced vital capacity (isoFEF25-75) were assessed at 3-minute intervals for 15 minutes and at 30 minutes. Spontaneous recovery was similarly evaluated. The time required to attain significant increases in both FEV1 and isoFEF25-75 was calculated in bronchodilator trials. With 20 micrograms of procaterol, both spacers allowed larger and faster FEV1 increases than the MDI alone (P < 0.01); with 50 micrograms, the velocity and magnitude of FEV1 increases were further enhanced in trials with the MDI alone. The lower procaterol dose via the large-volume spacer determined larger and faster isoFEF25-75 increases than the higher dose via both the small-volume spacer and the MDI alone (P < 0.01). Spacers enhance bronchodilation even in patients using MDIs optimally. Compared with both the small-volume device and the MDI alone, the large-volume spacer allows faster and larger small airway dilation with less than half of the procaterol dose.