成年人脂肪体重、去脂体重和肺通气功能的关系

本文旨在研究分析成年人去脂体重(fat free mass,FFM)、脂肪体重(fat mass,FM)和肺通气功能的关系。随机抽取黑龙江省部分地区19~81岁健康成年人群1307人(男性372人,女性935人),测量身高、体重,采用身体成分仪和肺功能仪分别检测FFM、FM和肺通气功能,并采用Pearson相关分析、独立样本t检验和多元逐步回归等统计学方法分析FFM、FM和肺通气功能的关系。结果显示,无论性别,年龄均与脂肪体重指数(FM index,FMI)呈正相关(P0.001),去脂体重指数(FFM index,FFMI)和用力肺活量(forced vital capacity,FVC)、用力呼气一秒量(forced expiratory volume in one second,FEV1)、最高呼气流量(peak expiratory flow,PEF)、用力呼出25%肺活量时呼气流量(forced expiratory flow at25%of forcedvital capacity,FEF25%)均呈正相关(P0.01),FMI和FVC、FEV1、FEF75%呈负相关(P0.05)。男性FMI和最大呼气中段流量(maximal mid-expiratory flow,MMEF)呈负相关(P0.05)。无论性别,FFMI对于FVC作用大于FMI,而对于FEV1,男性FMI作用大于FFMI,女性则反之。无论性别,FFMI升高,PEF和FEF25%也升高,而FMI对二者无作用。无论性别,FMI升高,FEF75%降低,而FFMI对其无作用。FMI升高,男性MMEF降低,女性无明显改变。本研究结果表明,FFM和FM均是影响肺通气功能的独立因素,反映骨骼肌力的FFM与肺通气功能呈正相关,FM与肺通气功能呈负相关。FFM和FM对肺通气功能作用大小存在差别。     

儿童青少年脂肪体重、去脂体重和肺通气功能的关系

本文旨在研究儿童青少年去脂体重(fat free mass,FFM)、脂肪体重(fat mass,FM)和肺通气功能的关系。随机抽取黑龙江省10～18岁健康儿童青少年1174人(男性583人,女性591人),测量身高、体重和腰臀比(waist to hip ratio,WHR),使用身体成分测量仪和肺功能仪分别测量FFM、FM和肺通气功能,采用独立样本t检验、偏相关和多元逐步回归分析FFM、FM和肺通气功能的关系。结果显示,无论性别,受试者年龄与去脂体重指数(FFM index,FFMI)呈正相关(P0.001)。男性年龄和脂肪体重指数(FM index,FMI)呈负相关(P0.001),女性年龄和FMI呈正相关(P0.001)。无论性别,受试者FFMI与用力呼气肺活量(forced vital capacity,FVC)、用力呼气一秒量(forced expiratory volume in one second,FEV1)、最大呼气流量(peak expiratory flow,PEF)、用力呼出25%肺活量时呼气流量(forced expiratory flow at25%of forced vital capacity,FEF25%)、FEF50%和最大呼气中段流量(maximum mid-expiratory flow,MMEF)都呈正相关(P0.05),与FEV1/FVC呈负相关(P0.01)。男性FFMI与FEF75%正相关(P0.05),女性FFMI与FEF75%不相关。男性FMI与FEV1、FEV1/FVC、PEF、FEF25%、FEF50%、FEF75%和MMEF呈负相关(P0.05),而与FVC不相关。女性FMI与肺通气功能的指标均不相关。除男性FEV1/FVC和FEF75%外,无论性别,FFMI对肺通气功能指标的预测作用大于FMI。FFMI对男性肺通气功能预测作用大于女性。男性肺功能突增发生在12～15岁:FVC较前一个年龄段分别增加10.05%、20.41%、11.75%和9.00%,FEV1分别较前一年龄段增加11.38%、20.07%、12.01%和9.14%。女性肺功能突增发生在12、13和18岁:FVC较前一年龄段分别增加13.73%、9.07%和9.76%,FEV1较前一年龄段分别增加13.17%、11.12%和10.62%。在肺功能突增期,无论性别,FFMI对肺功能的预测作用大于年龄的预测作用。综上所述,无论性别,反映骨骼肌力的FFM与肺通气功能呈正相关,对男性肺通气功能的预测作用大于女性。FM与男性肺通气功能呈负相关,而与女性肺通气功能不相关。在肺功能突增期,身高和FFM的快速增长可能是造成肺功能快速增长的主要原因。     

无症状吸烟者的肺功能改变情况分析

目的:探讨烟龄≥15年,日吸烟量≥15支的无症状男性吸烟者的肺功能改变情况。方法:选择男性无症状吸烟者190人及非吸烟者180人,进行肺功能测定,并比较两组人群的肺功能改变情况。结果:吸烟组与非吸烟组比较,肺活量(VC)、用力肺活量(FVC)、第1秒用力呼气容积(FEV1)、Tiffeneau 1秒率(FEV1/VC)结果改变不明显,而Gaensler 1秒率(FEV1/FVC)、最大分钟通气量(MVV)、用力呼气50%肺活量的呼气流量(FEF50%)、用力呼气75%肺活量的呼气流量(FEF75%)、呼出25%～75%肺活量时的平均流量(FEF25%～75%)、肺一氧化碳弥散量(DLCO)结果均有显著降低,有统计学意义。结论:通过对无症状吸烟人群肺功能测定结果进行分析。发现有些吸烟者虽无临床症状,但已经出现了小气道及肺弥散功能的损伤,提醒吸烟者应早期戒烟,关爱自身健康,净化生存环境,提高生活质量。     

无症状吸烟者的肺功能改变情况分析

目的：探讨烟龄215年,日吸烟量≥15支的无症状男性吸烟者的肺功能改变情况。方法：选择男性无症状吸烟者190人及非吸烟者180人,进行肺功能测定,并比较两组人群的肺功能改变情况。结果：吸烟组与非吸烟组比较,肺活量（VC）、用力肺活量（FVC）、第1秒用力呼气容积（FEV1）、Tiffeneau1秒率（FEV1／VC）结果改变不明显,而Gaensler1秒率（FEV1/FVC）、最大分钟通气量（MVV）、用力呼气50％肺活量的呼气流量（FEF50％）、用力呼气75％肺活量的呼气流量（FEF75％）、呼出25％-75％肺活量时的平均流量（FEF25％～75％）、肺一氧化碳弥散量（DLCO）结果均有显著降低,有统计学意义。结论：通过对无症状吸烟人群肺功能测定结果进行分析。发现有些吸烟者虽无临床症状,但已经出现了小气道及肺弥散功能的损伤,提醒吸烟者应早期戒烟,关爱自身健康,净化生存环境,提高生活质量。     

变异性咳嗽病人肺通气功能检测结果分析

目的分析肺通气功能检测在变异性咳嗽患者诊断中的价值。方法选择2013年1~12月在我院呼吸科门诊确诊为变异性咳嗽的患者80例(发作组),行肺通气功能检测,内容包括用力肺活量(FVC),第一秒最大时间肺活量(FEV1)一秒率(FEV1/FVC)测定,呼气流量峰值(PEF%)和最大呼气中段流量(FEV25%,FEV50%,FEV75%)等指标,并与同期健康体检者50例(对照组)对照分析。结果发作组肺通气功能指标低于对照组,小气道指标FEV25%,FEV50%,FEV75%,MMEF较大气道指标FEV1,MEFV,FEV1/FVC下降较明显。结论肺通气功能的检测可以评价变异性咳嗽患者的小气道功能障碍,为其诊断和病情的动态观察提供依据。     

慢性阻塞性肺疾病患者超声监测膈肌增厚率与肺功能的相关性

摘要 目的：探讨慢性阻塞性肺疾病(Chronic obstructive pulmonary disease,COPD)患者超声监测膈肌增厚率与肺功能的相关性。方法：2019年1月到2020年12月选择在本院诊治的COPD患者72例作为COPD组,同期选择在本院体检的健康人72例作为对照组。采用超声监测两组入选者的膈肌增厚率,使用肺功能测定仪测定呼气流量峰值(peak expiratory flow,PEF)、第1 秒用力呼气容积占预计值百分比(Forced Expiratory Volume in the first second,FEV₁)、肺活量25 %时用力呼气流速(Vmax25%,V25)、肺活量50 %时用力呼气流速(Vmax50%,V50)、肺活量75 %时用力呼气流速(Vmax75%,V75)等指标并进行相关性分析。结果：COPD组的膈肌增厚率低于对照组,对比差异有统计学意义(P<0.05)。COPD组的FEV₁、PEF、V25、V50、V75值都低于对照组,对比差异都有统计学意义(P<0.05)。在COPD组患者中,Pearson相关分析显示膈肌增厚率与FEV₁、PEF、V25、V50、V75都存在正相关性(P<0.05)。Logistic回归分析显示FEV₁、PEF、V25、V50、V75为影响膈肌增厚率的重要影响因素P<0.05)。结论：COPD患者超声监测可显示膈肌增厚率与肺功能降低,两者存在相关性,肺功能下降也是导致患者膈肌增厚率降低的重要危险因素。     

超声引导下不同TPV对单孔胸腔镜肺癌根治术患者MCP-1、PGE2等指标的影响

目的:探讨超声引导下不同胸椎旁神经阻滞(thoracic paravertebral nerve block, TPVB)对单孔胸腔镜肺癌根治术患者巨噬细胞趋化蛋白-1 (monocyte chemotactic protein-1,MCP-1)、血浆前列腺素E-2(prostaglandin E-2,PGE 2)等指标的影响。方法:选择我院2016年1月至2019年12月收治的96例择期行单孔胸腔镜的肺癌根治术患者,A组采用全身麻醉+自控静脉镇痛法,B组采用全麻+单次TPVB+自控静脉镇痛方法,C组采用全麻+连续TPVB麻醉法,对比三组的不同时间点的动脉血氧分压(partial arterial oxygen pressure,PaO_2)、动脉二氧化碳分压(arterial carbon dioxide partial pressure,PaCO_2)、肺泡动脉血氧分压差(difference of alveolar arterial oxygen partial pressure,P_(A-a)O_2)、1秒用力呼气容量(1 second forced expiratory volume,FEV_1)、用力肺活量(forced vital capacity,FVC)、最大呼气中段流量(maximum expiratory flow,MMF)等。结果:T3及T4点时,三组的PaO_2、FEV_1、FVC、MMF较T0点明显降低,三组以上指标水平为A组B组C组,P_(A-a)O_2较T0点明显升高,为A组B组C组(P0.05)。三组的MCP-1、PGE2及TNF-α水平在T0点时对比无差异(P0.05),T3、T4点时,三组以上指标明显上升,A组B组C组(P0.05)。结论:全麻联合TPVB超声引导下连续TPBV法可改善患者的肺功能,促进肺部氧合,可能与其可对患者炎性指标影响较小有关。     

肺炎3号联合金银花治疗儿童肺炎对患儿呼吸功能和炎症反应水平影响

摘要 目的：探讨肺炎3号联合金银花治疗儿童肺炎对患儿呼吸功能和炎症反应水平影响。方法：选取我院2017年2月-2019年4月期间收治的80例肺炎患儿,随机分成对照组和观察组,每组40例,对照组患儿采取阿奇霉素治疗,观察组患儿采取肺炎3号联合金银花治疗,对比不同治疗方法对患儿呼吸功能和炎症反应水平影响。结果：两组患儿治疗前用力肺活量（forced vital capacity,FVC）、第1秒用力呼气容积（orced expiratory volume in 1 second,FEV₁）、用力呼气峰流速(expiratory peak flow rate,PEF)对比无统计学差异（P＞0.05）,治疗后,观察组患儿上述肺功能指标均明显高于对照组（P＜0.05）。两组治疗前患儿血清肿瘤坏死因子（tumor necrosis factor-α,TNF-α）、白介素（interleukin,IL）-6、IL-10对比无统计学差异（P＞0.05）,治疗后,观察组患儿TNF-α、IL-6均明显低于对照组,且观察组IL-10明显高于对照组（P＜0.05）。患儿啰音消失时间、止咳时间、气促消失时间、热退时间以及住院时间对比发现对照组明显长于观察组（P＜0.05）。在治疗总效率方面,观察组明显更高（P＜0.05）。结论：儿童肺炎采取肺炎3号联合金银花治疗效果确切,可明显改善患儿呼吸功能,抑制机体炎性细胞因子,有效改善患儿临床症状,具有一定临床意义。     

Wistar大鼠肺功能参考值范围测定

目的建立Wistar大鼠肺功能各项指标的参考值。方法用创体描法小动物肺功能检测仪检测大鼠肺功能各项指标,根据肺功能指标检测结果,通过统计分析,确定其参考值范围。结果 Ri（吸气阻力）为1.81（0.94~4.10）cm H2O/（mL·s）,Re（呼气阻力）为1.83（0.71~3.57）cm H2O/（mL·s）,Cl（肺顺应性）为0.15（0.05~0.29）mL/cm H2O,MVV（最大通气量）为144.65（77.28~256.20）mL/min,FVC（用力肺活量）为8.49（5.82~12.70）mL,Fev0.2（第0.2秒用力呼气容积）为5.72（3.62~7.01）mL,Fev0.2/FVC（第0.2秒用力呼出容积占用力肺活量百分比）为8.12（39.14~85.28）%,FEF（25~75）%（用力中期呼气流速）为34.11（28.25~46.87）mL/min。PEF（用力最大呼气流速）为38.28（30.75~50.25）mL/min。结论 Wistar大鼠肺功能指标的参考值范围可为临床和科研工作以及未来制定国家标准和规范提供参考依据。     

中重度支气管哮喘急性发作期患儿Fe NO表达水平与肺功能的相关性研究

摘要 目的：探究中重度支气管哮喘急性发作期患儿呼出气一氧化氮（Fe NO）表达水平与肺功能的相关性。方法：选择2016年3月-2019年3月来我院就诊的中重度支气管哮喘急性发作期患儿69例为观察组,其中,中度支气管哮喘急性发作期患儿58例,重度支气管哮喘急性发作期患儿11例;另选取同期来我院体检的69例正常健康儿童作为对照组,对比观察组中中度、重度支气管哮喘急性发作期患儿Fe NO表达水平、用力肺活量（forced vital capacity,FVC）、最大呼气流量占预计值百分比（Maximum expiratory flow as a percentage of expected value,PEF%）、第一秒用力呼气容积占预计值的百分比（Forced expiratory volume as a percentage of expected value in the first second,FEV1%）与对照组健康儿童的差异,并对观察组患儿Fe NO表达水平与肺功能的相关性进行分析。结果：观察组患儿的Fe NO表达水平均高于对照组,且重度组患儿的Fe NO表达水平明显高于中度组（P＜0.05）;观察组患儿的PEF%、FEV₁%、FVC水平均高于对照组,且重度组患儿的PEF%、FEV₁%、FVC水平均高于中度组（P＜0.05）;观察组患儿Fe NO表达水平与FVC、PEF%、FEV₁%指标均呈负相关关系（r=-0.503、-0.551、-0.532,P均＜0.05）。结论：中重度支气管哮喘急性发作期患儿Fe NO表达水平与肺功能成负相关,可通过监测 Fe NO 水平间接判断炎症程度。     

Relation between fat mass, fat free mass and ventilatory function in children and adolescents

The aim of the present study was to evaluate the relation between fat mass (FM), fat free mass (FFM) and ventilatory function in children and adolescents. 1 174 healthy children and adolescents (583 males and 591 females) aged 10-18 years were selected from Heilongjiang Province through random sampling by means of questionnaire and physical examination, and measured for height, weight, waist to hip ratio (WHR), FM, FFM and ventilatory function. The data were analyzed by means of independent-samples t test, Pearson correlation analysis and multi-factors regression analysis. Regardless of sex, an independent positive correlation was found (P<0.001) between age and FFM index (FFMI). FM index (FMI) correlated negatively with age in males (P<0.001), but positively with age in females (P<0.001). Regardless of sex, FFMI correlated positively with forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), forced expiratory flow at 25% of forced vital capacity (FEF25%), FEF50%, and maximal mid-expiratory flow (MMEF) (P<0.05), while negatively with FEV1/FVC (P<0.01). FFMI was correlated positively with FEF75% in males (P<0.05), but not correlated in females. In males, FMI correlated negatively with FEV1, FEV1/FVC, PEF, FEF25%, FEF50%, FEF75% and MMEF (P<0.05), but not correlated with FVC. No correlation was found between the ventilatory function indices and FMI in females. Except FEV1/FVC and FEF75% in males, the effect of FFMI in predicting ventilatory function was higher than FMI regardless of sex. Moreover, the predicting effect of FFMI was higher in males than that in females. Growth spurt of lung function occurred in the ages of 12-15 years in males, while in the ages of 12, 13 and 18 years in females. During the period of growth spurt of lung function, regardless of sex, the effect of FFMI in predicting the lung function was higher than that of age. In conclusion, regardless of sex, FFMI correlates positively with ventilatory function, as a reflection of muscle mass. The effect of FFM in predicting ventilatory function is higher in males than that in females. FM correlates negatively with ventilatory function in males, but not in females. The rapid growth of height and FFM are possibly the main reasons for growth spurt of lung function.     

Pulmonary function in men after oxygen breathing at 3.0 ATA for 3.5 h.

As a pulmonary component of Predictive Studies V, designed to determine O2 tolerance of multiple organs and systems in humans at 3.0-1.5 ATA, pulmonary function was evaluated at 1.0 ATA in 13 healthy men before and after O2 exposure at 3.0 ATA for 3.5 h. Measurements included flow-volume loops, spirometry, and airway resistance (Raw) (n = 12); CO diffusing capacity (n = 11); closing volumes (n = 6); and air vs. HeO2 forced vital capacity maneuvers (n = 5). Chest discomfort, cough, and dyspnea were experienced during exposure in mild degree by most subjects. Mean forced expiratory volume in 1 s (FEV1) and forced expiratory flow at 25-75% of vital capacity (FEF25-75) were significantly reduced postexposure by 5.9 and 11.8%, respectively, whereas forced vital capacity was not significantly changed. The average difference in maximum midexpiratory flow rates at 50% vital capacity on air and HeO2 was significantly reduced postexposure by 18%. Raw and CO diffusing capacity were not changed postexposure. The relatively large change in FEF25-75 compared with FEV1, the reduction in density dependence of flow, and the normal Raw postexposure are all consistent with flow limitation in peripheral airways as a major cause of the observed reduction in expiratory flow. Postexposure pulmonary function changes in one subject who convulsed at 3.0 h of exposure are compared with corresponding average changes in 12 subjects who did not convulse.     

Spirometry in the Evaluation of Pulmonary Function

Spirometry should be more widely used in routine examinations. Equipment should meet the individual physician''s or hospital''s needs and include either a dependable water-sealed spirometer or an easily calibrated and accurate electronic spirometer. Justifiable concern over the reliability of electronic spirometers has resulted in requests to determine performance standards for these medical devices. Predicted normal standards must apply to the particular spirometer. Recommended tests are those of vital capacity (VC), forced vital capacity (FVC), one-second forced expiratory volume (FEV₁), the ratio of one-second forced expiratory flow (FEF200-1200) and forced midexpiratory flow (FEF25-75 percent). The maximum voluntary ventilation (MVV) test may be useful for evaluation of work disability and detection of extrathoracic obstruction. Additional consideration may be given to measurements of total lung capacity (TLC) to discriminate between restrictive and obstructive impairment and the forced end-expiratory flow (FEF75-85 percent) to detect mild small airway obstruction. At this time, flow-volume curves measurement cannot be justified for routine clinical use.     

Respiratory morbidity 10 years after the Union Carbide gas leak at Bhopal: a cross sectional survey. The International Medical Commission on Bhopal.

OBJECTIVE: To examine the role of exposure to the 1984 Bhopal gas leak in the development of persistent obstructive airways disease. DESIGN: Cross sectional survey. SETTING: Bhopal, India. SUBJECTS: Random sample of 454 adults stratified by distance of residence from the Union Carbide plant. MAIN OUTCOME MEASURES: Self reported respiratory symptoms; indices of lung function measured by simple spirometry and adjusted for age, sex, and height according to Indian derived regression equations. RESULTS: Respiratory symptoms were significantly more common and lung function (percentage predicted forced expiratory volume in one second (FEV1), forced vital capacity (FVC), forced expiratory flow between 25% and 75% of vital capacity (FEF25-75), and FEV1/FVC ratio) was reduced among those reporting exposure to the gas leak. The frequency of symptoms fell as exposure decreased (as estimated by distance lived from the plant), and lung function measurements displayed similar trends. These findings were not wholly accounted for by confounding by smoking or literacy, a measure of socioeconomic status. Lung function measurements were consistently lower in those reporting symptoms. CONCLUSION: Our results suggest that persistent small airways obstruction among survivors of the 1984 disaster may be attributed to gas exposure.     

Forced expiration: a test for airflow obstruction in horses.

The purpose of this study was to assess whether our method of inducing forced expiration detects small airway obstruction in horses. Parameters derived from forced expiratory flow-volume (FEFV) curves were compared with lung mechanics data obtained during spontaneous breathing in nine healthy horses, in three after histamine challenge, and in two with chronic obstructive pulmonary disease (COPD) pre- and posttherapy with prednisone. Parameters measured in the healthy horses included forced vital capacity (FVC = 41.6 +/- 5.8 liters; means +/- SD) and forced expiratory flow (FEF) at various percentages of FVC (range of 20.4-29.7 l/s). Histamine challenge induced a dose-dependent decrease in FVC and FEF at low lung volume. After therapy, lung function of the two COPD horses improved to a point where one horse had normal lung mechanics during tidal breathing; however, FEF at 95% of FVC (4.9 l/s) was still decreased. We concluded that FEFV curve analysis allowed the detection of induced or naturally occurring airway obstruction.     

Influence of passive smoking on basic anthropometric characteristics and respiratory function in young athletes

The primary objective of this study is to investigate the maintenance difference in basic anthropometric characteristics and to outline the dynamics of respiratory function change in youngsters athletes exposed to passive smoking (PS) and athletes not exposed to passive smoking in their families (NPS). High and weight were determined as basis anthropometric characteristics. Measured parameters for respiratory function were vital capacity (VC), forced expiratory volume in the first second (FEV1), maximum expiratory flow (PEF), forced expiratory flow at 50% forced vital capacity (MEF 50) and forced expiratory flow at 25% forced vital capacity (MEF 25). Significant statistical differences in separate spirometric variable were found in three variables (FEV1, MEF50, and MEF25) for group older youngsters. Analysis of variance showed statistical differences between athletes unexposed to passive smoking (NPS) and athletes exposed to passive smoking (PS) in even four spirometric variables (VC, FEV1, MEF50 and MEF25).     

肺炎支原体抗体阳性对咳嗽变异性哮喘患儿肺功能的影响研究

目的:通过探讨肺炎支原体(MP)抗体阳性感染对咳嗽变异性哮喘(CVA)患儿肺功能的影响,为临床治疗提供依据。方法:选择2012年6月~2014年6月本院收治的CVA患儿共60例,依据支原体抗体检查和肺功能检测结果,分为CVA合并MP组(合并组)和CVA组,检测两组患儿初诊时肺通气功能、支气管激发试验阳性率,分析初诊时、治疗1、3个月后MP抗体对肺功能第一秒用力呼吸容积/用力肺活量(FEV1%)的影响。结果:初诊时两组患儿肺活量(FVC)、最大呼气峰流速(PEF)、FEV1%、最大中段呼气流速(MMEF75/25)实测值均低于预测值(P0.05),合并组MMEF75/25预测值/实测值的比值较CVA组高(P0.05)。支气管激发试验阳性患儿中,合并组以轻度和极轻度为主,CVA组以重度和中度为主(P0.05)。MP抗体滴度持续阳性和阴性患儿FEV1%无统计学差异(P0.05)。结论:合并MP抗体阳性CVA患儿气道高反应性程度较低,小气道阻塞加重,对肺通气功能无影响。     

Model of forced expiratory flows and airway geometry in infants.

Early measurements of autopsied lungs from infants, children, and adults suggested that the ratio of peripheral to central airway resistance was higher in infants than older children and adults. Recent measurements of forced expiration suggest that infants have high flows relative to lung volume. We employed a computational model of forced expiratory flow along with physiological and anatomic data to evaluate whether the infant lung is a uniformly scaled-down version of the adult lung. First, we uniformly scaled an existing computational model of adult forced expiration to estimate forced expiratory flows (FEF) and density dependence for an 18-mo-old infant. The values obtained for FEF and density dependence were significantly lower than those reported for healthy 18-mo-old infants. Next, we modified the model for the infant lung to reproduce standard indexes of expiratory flow [forced expiratory volume in 0.5 s (FEV(0.5)), FEFs after exhalation of 50 and 75% forced vital capacity, FEF between 25 and 75% expired volume] for this age group. The airway sizes obtained for the infant lung model that produced accurate physiological measurements were similar to anatomic data available for this age and larger than those in the scaled model. Our findings indicate that the airways in the infant lung model differ from those in the scaled model, i.e., middle and peripheral airway sizes are larger than result from uniform downscaling of the adult lung model. We show that the infant lung model can be made to reproduce individual flow-volume curves by adjusting lumen area generation by generation.     

Short-term hypoxic exposure at rest and during exercise reduces lung water in healthy humans.

Hypoxia and hypoxic exercise increase pulmonary arterial pressure, cause pulmonary capillary recruitment, and may influence the ability of the lungs to regulate fluid. To examine the influence of hypoxia, alone and combined with exercise, on lung fluid balance, we studied 25 healthy subjects after 17-h exposure to 12.5% inspired oxygen (barometric pressure = 732 mmHg) and sequentially after exercise to exhaustion on a cycle ergometer with 12.5% inspired oxygen. We also studied subjects after a rapid saline infusion (30 ml/kg over 15 min) to demonstrate the sensitivity of our techniques to detect changes in lung water. Pulmonary capillary blood volume (Vc) and alveolar-capillary conductance (D(M)) were determined by measuring the diffusing capacity of the lungs for carbon monoxide and nitric oxide. Lung tissue volume and density were assessed using computed tomography. Lung water was estimated by subtracting measures of Vc from computed tomography lung tissue volume. Pulmonary function [forced vital capacity (FVC), forced expiratory volume after 1 s (FEV(1)), and forced expiratory flow at 50% of vital capacity (FEF(50))] was also assessed. Saline infusion caused an increase in Vc (42%), tissue volume (9%), and lung water (11%), and a decrease in D(M) (11%) and pulmonary function (FVC = -12 +/- 9%, FEV(1) = -17 +/- 10%, FEF(50) = -20 +/- 13%). Hypoxia and hypoxic exercise resulted in increases in Vc (43 +/- 19 and 51 +/- 16%), D(M) (7 +/- 4 and 19 +/- 6%), and pulmonary function (FVC = 9 +/- 6 and 4 +/- 3%, FEV(1) = 5 +/- 2 and 4 +/- 3%, FEF(50) = 4 +/- 2 and 12 +/- 5%) and decreases in lung density and lung water (-84 +/- 24 and -103 +/- 20 ml vs. baseline). These data suggest that 17 h of hypoxic exposure at rest or with exercise resulted in a decrease in lung water in healthy humans.     

Ventilatory Tests and Pulmonary Conductance in Hospitalized Patients

In a series of 49 patients, including individuals with varying lung pathology and some older patients with no lung disease, the usual excellent correlation between first-second forced expiratory volume and maximum breathing capacity was found (coefficient of correlation=0.88). The first-second forced expiratory volume and maximum mid-expiratory flow rate were also seen to be closely related (coefficient of correlation=0.87). The relationship between these ventilatory tests and direct mechanical measurements of pulmonary resistance, however, was not as striking. Reduction in pulmonary compliance not due to loss or removal of pulmonary tissue did not affect the interrelationships between these tests. First-second forced expiratory volume, expressed as a percentage of the predicted vital capacity, was more closely related to the expression “% of predicted maximum breathing capacity” than the first-second forced expiratory volume, expressed as a percentage of the actual vital capacity (p<.05).