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Inspiratory Capacity (inspiratory + capacity)
Selected AbstractsEffects of ozone exposure in rat lungs investigated with hyperpolarized 3He MRIJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2008Yannick Crémillieux PhD Abstract Purpose To investigate the effects of subchronic ozone exposure on rat lung ventilation using hyperpolarized (HP) 3He MRI. Materials and Methods A total of 24 Sprague-Dawley rats, distributed in one control group and four groups exposed to 0.5 ppm ozone concentration for two days or six days, either continuously (22 hours/day) or alternatingly (12 hours/day). A three-step MRI protocol was designed and applied to each animal, including: 1) 3He gas distribution images acquired at inspiratory capacity, 2) measurements of intrapulmonary 3He diffusion coefficients, and 3) dynamic ventilation acquisitions performed during lung filling with 3He. Results No differentiation between animals exposed to ozone and control animals was observed from the ventilation images obtained at inspiratory capacity. The 3He diffusion coefficients were not statistically different from one group to another. Ventilation defects, appearing as delayed lung filling regions and heterogeneous lung filling, were observed in the dynamic lung ventilation image series. The percentage of animals with ventilation defects in the control, two-day, and six-day exposed groups were equal to 20%, 43% and 75%, respectively. In the subgroup of the animals exposed six days for 12 hours per day, the percentage of animals exhibiting ventilation defects was equal to 85%. Conclusion Heterogeneous obstructive patterns in an experimental animal model of subchronic ozone exposure were observed using HP 3He MRI. J. Magn. Reson. Imaging 2008;27:771,776. © 2008 Wiley-Liss, Inc. [source] Forced inspiratory flow volume curve in healthy young childrenPEDIATRIC PULMONOLOGY, Issue 2 2009Daphna Vilozni PhD Abstract Introduction Spirometry testing should include both expiratory and inspiratory measurements. Inspiratory forced maneuvers can demonstrate extrathoracic airway abnormalities, of which various symptoms may suggest asthma. However, the inspiratory portion of the forced flow/volume maneuver in young healthy children has not yet been described. Objectives To document and analyze the forced inspiratory flow volume curve indices in healthy young children. Settings and Participants Healthy preschool children (age 2.5,6.5 years) from community kindergartens around Israel. Methods The teaching method included multi-target, interactive spirometry games and accessory games for inspiration (e.g., inspiratory whistle). Results One hundred and fourteen out of a total of 157 children performed duplicate full adequate inspiratory maneuvers. Repeatability between two maneuvers was 5.6%, 4.0%, 5.1%, 7.3% for inspiratory capacity (IC), forced inspiratory vital capacity (FIVC), peak inspiratory flow (PIF), and mid inspiratory flow (FIF50). Inspiratory flow indices were significantly lower than the expiratory flow indices. The time to reach PIF was significantly longer (mean,±,SD; 229,±,21 msec) than the time to reach peak expiratory flow (92,±,8 msec; P,<,0.0001). The shape of the inspiratory curve was parabolic and did not vary with age. The formed predicted equations were in agreement with the extrapolated values for older healthy children. Conclusions The majority of healthy young children can perform reliable maximum inspiratory flow volume curves. Our results provide a framework of reference equations for maximum inspiratory flow volume curve in the young children. The clinical applications of these equations have to be explored. Pediatr Pulmonol. 2009; 44:105,111. © 2009 Wiley-Liss, Inc. [source] Cardiopulmonary responses of asthmatic children to exercise: Analysis of systolic and diastolic cardiac functionPEDIATRIC PULMONOLOGY, Issue 3 2007Bulent Alioglu MD Abstract The aim of this study was to evaluate aerobic exercise capacity, cardiac features and function in a group of asthmatic children who underwent medical treatment. Dynamic exercise testing was done to evaluate aerobic exercise capacity. Echocardiography was performed to identify the effects that asthma-induced pulmonary changes have on respiratory and cardiac function in these patients. The study involved 20 asthmatic children (aged 7,16 years) who were followed at our hospital and 20 age- and sex-matched, healthy control subjects. Sixteen of the asthma cases were moderate and four were severe. All 40 subjects underwent similar series of assessments: multiple modes of echocardiography, treadmill stress testing, pulmonary function testing. The means for forced expiratory volume in 1 sec, forced expiratory flow 25,75%, maximal voluntary ventilation and inspiratory capacity were all significantly higher in the control group. The patient group had significantly lower mean maximal oxygen uptake and mean endurance time than the controls but there were no significant differences between the groups with respect to respiratory exchange ratio or the ventilatory threshold. The control group means for ejection fraction, fractional shortening, left ventricular mass, and left ventricular mass index were significantly higher than the corresponding patient group results. Children with moderate or severe asthma have lower aerobic capacity than healthy children of the same age. The data suggest that most of these children have normal diastolic cardiac function, but exhibit impaired systolic function and have lower LVM than healthy peers of the same age. Pediatr Pulmonol. 2007; 42:283,289. © 2007 Wiley-Liss, Inc. [source] Mechanical ventilatory constraints during incremental cycle exercise in human pregnancy: implications for respiratory sensationTHE JOURNAL OF PHYSIOLOGY, Issue 19 2008Dennis Jensen The aim of this study was to identify the physiological mechanisms of exertional respiratory discomfort (breathlessness) in pregnancy by comparing ventilatory (breathing pattern, airway function, operating lung volumes, oesophageal pressure (Poes)-derived indices of respiratory mechanics) and perceptual (breathlessness intensity) responses to incremental cycle exercise in 15 young, healthy women in the third trimester (TM3; between 34 and 38 weeks gestation) and again 4,5 months postpartum (PP). During pregnancy, resting inspiratory capacity (IC) increased (P < 0.01) and end-expiratory lung volume decreased (P < 0.001), with no associated change in total lung capacity (TLC) or static respiratory muscle strength. This permitted greater tidal volume (VT) expansion throughout exercise in TM3, while preserving the relationship between contractile respiratory muscle effort (tidal Poes swing expressed as a percentage of maximum inspiratory pressure (PImax)) and thoracic volume displacement (VT expressed as a percentage of vital capacity) and between breathlessness and ventilation . At the highest equivalent work rate (HEWR = 128 ± 5 W) in TM3 compared with PP: , tidal Poes/PImax and breathlessness intensity ratings increased by 10.2 l min,1 (P < 0.001), 8.8%PImax (P < 0.05) and 0.9 Borg units (P < 0.05), respectively. Pulmonary resistance was not increased at rest or during exercise at the HEWR in TM3, despite marked increases in mean tidal inspiratory and expiratory flow rates, suggesting increased bronchodilatation. Dynamic mechanical constraints on VT expansion (P < 0.05) with associated increased breathlessness intensity ratings (P < 0.05) were observed near peak exercise in TM3 compared with PP. In conclusion: (1) pregnancy-induced increases in exertional breathlessness reflected the normal awareness of increased and contractile respiratory muscle effort; (2) mechanical adaptations of the respiratory system, including recruitment of resting IC and increased bronchodilatation, accommodated the increased VT while preserving effort,displacement and breathlessness, relationships; and (3) dynamic mechanical ventilatory constraints contributed to respiratory discomfort near the limits of tolerance in late gestation. [source] Plethysmography and impulse oscillometry assessment of tiotropium and ipratropium bromide; a randomized, double-blind, placebo-controlled, cross-over study in healthy subjectsBRITISH JOURNAL OF CLINICAL PHARMACOLOGY, Issue 4 2006D. Singh Aims Spirometry, plethysmography and impulse oscillometry (IOS) measure different aspects of lung function. These methods have not been compared for their ability to assess long- and short-acting anticholinergic agents. We therefore performed a double-blind, placebo-controlled, four-way cross-over study in 30 healthy subjects. Methods Single doses of tiotropium bromide (Tio) 54 and 18 mcg, ipratropium bromide (IB) 40 mcg and placebo were administered. Specific conductance (sGaw), total lung capacity (TLC), inspiratory capacity (IC) and residual volume (RV) were measured using plethysmography, while IOS measured resistance (R5,25) and reactance (RF and X5). Pulmonary function was measured for 26 h post dose. Results Tio caused significant improvements in sGaw, forced expiratory voume in 1 s (FEV1), maximum mid-expiratory flow (MMEF) and R5,R25 at time points up to 26 h, with no clear differences between doses. IB improved the same parameters, but only up to 8 h. The weighted mean change (0,24 h) caused by Tio 54 mcg compared with placebo for FEV1 was 240 ml (95% confidence interval 180, 300), while for sGaw the ratio of geometric means (Tio compared with placebo) was 1.35 (1.28, 1.41). Neither drug caused consistent statistically significant changes in RF, forced vital capacity, TLC or IC over 26 h. RV was significantly improved from 8 to 24 h by Tio 54 mcg only. Conclusions In addition to spirometry, IOS resistance measurements and sGaw can distinguish between the effects of long- and shortacting anticholinergic effects in healthy subjects. [source] IMPROVING THE CADMIUM-INDUCED CENTRIACINAR EMPHYSEMA MODEL IN RATS BY CONCOMITANT ANTI-OXIDANT TREATMENTCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 11 2008S Heili Frades SUMMARY 1The aim of the present study was to perform an evolutionary analysis of the morphometrical, biochemical and functional parameters of centriacinar emphysema induced by cadmium chloride (CdCl2) in rats and to determine the effects of concomitant N -acetylcysteine (NAC) administration. 2Male Wistar rats were instilled orotracheally with either CdCl2 (n = 24) or saline (n = 24). One group of rats, consisting of both CdCl2 - and saline-treated rats, was fed a normal diet (n = 24), whereas the other group received NAC (n = 24). 3Changes in inspiratory capacity (IC), lung compliance (CL), expiratory flow at 75% (F75), forced vital capacity (FVC) and hydroxyproline content were assessed 2, 8, 21 and 45 days after instillation. Polymorphonuclear cells were evaluated 2 and 8 days after instillation and the mean linear intercept (Lm) was determined at 21 and 45 days. 4Over time, CdCl2 instillation causes several changes that are bound up with centriacinar emphysema. The concomitant administration of NAC to CdCl2 -treated rats partially reversed Lm at 21 days compared with CdCl2 alone (115 ± 2 vs 127 ± 2, respectively; P < 0.05). However, 45 days after instillation, NAC improved lung function in CdCl2 -treated rats compared with that in the saline-treated control group (IC 14.64 vs 15.25, respectively (P = 0.054); FVC 16.94 vs 16.28, respectively (P = 0.052), F75 31.41 vs 32.48, respectively (P = 0.062)). In addition, 45 days after instillation, NAC reduced lung collagen content in both the saline-treated control (100 vs 81% alone and in the presence of NAC, respectively) and CdCL2-treated groups (213 vs 161% alone and in the presence of NAC, respectively). In addition, although the results were not significant, NAC tended to reduce Lm and enhance CL in NAC + CdCl2 -treated rats. 5In conclusion, NAC partially improved emphysematous changes and reduced collagen deposition, which diminished the CdCl2 -induced fibrotic component of centriacinar emphysema. [source] | ||||||||||