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PubMed1996

Pulmonary function in children treated for rhabdomyosarcoma.

Chemotherapy, radiation therapy, and surgical intervention have markedly improved the survival of patients treated for rhabdomyosarcoma. Unfortunately, the therapy may have deleterious effects on the lung. Pulmonary functions tests were obtained from 17 patients treated for rhabdomyosarcoma because of our concern regarding potential pulmonary dysfunction in this group of patients who had received bleomycin, which is known to be associated with lung injury. Mean age at the time of the diagnosis of rhabdomyosarcoma was 10.1 (+/- 7.2) years (range 0.01-23.5 years). The mean age at the time of pulmonary function testing was 17.0 (+/- 7.5) years (range 5.8-34.0 years). Study patients reportedly had no pulmonary symptoms. Approximately 87% of study patients had a restrictive ventilatory impairment on pulmonary function testing as measured by total lung capacity (TLC) values less than the lower limit of normal. Approximately 70% of study patients had carbon monoxide diffusing capacity (DLCO) values less than the lower limit of normal. There were no significant differences in pulmonary function parameters when male study patients were compared to female study patients. There was a statistically significant lower forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio (P=0.03) and percent predicted forced expiratory flow at 25-75% of the FVC (FEF25-75; P=0.03) in the group of patients diagnosed with rhabdomyosarcoma over 8 years of age as compared to those individuals diagnosed under 8 years of age. In addition, there were no statistically significant differences in pulmonary function when the variables of sex and age at diagnosis (as outlined above) were studied in combination. In summary, we identified a high incidence of restrictive ventilatory abnormalities in a group of individuals (predominantly children) treated for rhabdomyosarcoma as well as a significantly lower FEV1/FVC ratio and percent predicted FEF25-75 in the group of patients diagnosed with the neoplasm over 8 years of age. Individuals caring for such patients are encouraged to obtain pre- and sequential posttreatment pulmonary function tests.

Adolescent↗
PubMed2002

Increased surface tension decreases pulmonary capillary volume and compliance.

Increased surface tension is an important component of several respiratory diseases, but its effects on pulmonary capillary mechanics are incompletely understood. We measured capillary volume and specific compliance before and after increasing surface tension with nebulized siloxane in excised dog lungs. The change in surface tension was sufficient to increase lung recoil 5 cm H(2)O at 50% total lung capacity. Increased surface tension decreased both capillary volume and specific compliance. The changes in capillary volume and compliance were greatest at the lung volumes at which the surface tension change was greatest. Near functional residual capacity, capillary volume postsiloxane was approximately 30% of control. Presiloxane capillary specific compliance was approximately 7%/cm H(2)O near functional residual capacity and approximately 2.5%/cm H(2)O near total lung capacity. Postsiloxane capillary-specific compliance was 3%/cm H(2)O, and was independent of lung volume. We conclude that in addition to their well-known effects on lung mechanics, changes in surface tension also have important effects on capillary mechanics. We speculate that these changes may in turn affect ventilation and perfusion, worsen gas exchange, and alter leukocyte sequestration.

Animals↗
PubMed1997

Eglin-c prevents monocrotaline-induced ventilatory dysfunction.

The present study was carried out to investigate the relationship between elastase and monocrotaline (MCT)-induced ventilatory dysfunction in rats. To accomplish this, we used an elastase inhibitor eglin-c to suppress the activity of endogenous elastase. Thirty-five young Sprague-Dawley rats were randomly divided into six groups: control, MCT, eglin-c(1), eglin-c(2), eglin-c(1) + MCT, and eglin-c(2) + MCT. Rats in the control group received no treatment. Each MCT rat received a single subcutaneous injection of MCT (60 mg/kg) 1 wk before the functional test. Each eglin-c(1) rat was intratracheally instilled with eglin-c (9 mg/rat) twice in 1 wk. Each eglin-c(2) rat was intratracheally instilled with eglin-c (9 mg/rat) five times in 1 wk. Both eglin-c + MCT groups were treated with the combination of eglin-c(1) or eglin-c(2) and MCT. In the MCT group, there were significant decreases in dynamic respiratory compliance, maximal expiratory flow rate at 50% total lung capacity, and the slopes of the maximal expiratory flow-%total lung capacity curve and the maximal expiratory flow-static recoil pressure curve. However, in the eglin-c(1) + MCT and eglin-c(2) + MCT groups, all of the above-mentioned MCT-induced changes were prevented. All ventilatory values of the eglin-c(1) and eglin-c(2) groups were not significantly different from those of the control group. These results demonstrate that eglin-c treatment prevents MCT-induced ventilatory dysfunction and suggest that endogenous elastase may play an important role in MCT-induced inflammation-mediated ventilatory abnormality.

Animals↗
PubMed1996

The effects of age, sex, lung size, and hyperinflation on CT lung densitometry.

OBJECTIVE: To test our proposal that, on high-resolution CT scans, the relative area of the lung with attenuation values lower than -950 H (RA950) can be a measurement of pulmonary emphysema, we examine the possible influences of sex, age, lung size, and hyperinflation on CT lung densitometry. SUBJECTS AND METHODS: The RA950 and the mean lung density (MLD) were measured in 42 healthy subjects (21 men, 21 women) from 23 to 71 years old, in 10 patients with asthma before and after a bronchial challenge test, and in seven patients with asthma who have irreversible hyperinflation (defined as an increased total lung capacity). RESULTS: In the healthy subjects, we found no significant difference between sexes and no significant correlation between age and the MLD, but we found a significant correlation between age and the RA950. In addition, we found a significant correlation between the total lung capacity expressed as absolute values and both the RA950 and the MLD. We did not observe any effect of acute airflow limitation either on the MLD or on the RA950 in the asthmatic subjects after the bronchial challenge test. Likewise, we observed no change in either the MLD or the RA950 in the asthmatic subjects with chronic hyperinflation. CONCLUSION: This study shows that CT lung densitometry is influenced by total lung capacity and, to a lesser degree, by age. Thus, this study suggests that normal CT attenuation values for the lung should be established.

Absorptiometry, Photon↗
PubMed1992

Postoperative pulmonary complication rate and long-term changes in respiratory function following esophagectomy with esophagogastrostomy.

Upper abdominal surgery has a high incidence of postoperative respiratory complications. Although operations involving a thoracic as well as an upper abdominal incision as encountered in esophageal surgery are likely to be associated with an even higher complication rate and perhaps permanent alterations of respiratory function, only a few studies have addressed this problem. We evaluated the postoperative course of patients undergoing thoracoabdominal esophagectomy with esophagogastrostomy. Twenty patients were evaluated, of whom 10 (50%) developed respiratory complications as defined by our criteria, which were the simultaneous occurrence of rectal temperature over 38 degrees C on the first postoperative day and radiographic evidence of pulmonary infiltration. Although there is no general consensus regarding the diagnostic criteria of a postoperative pulmonary complication, we were able to validate the clinical relevance of our definition by showing that these patients suffered from a more severe and more prolonged impairment of global oxygen exchange than those who did not fulfill the criteria. They also required a longer period of respiratory support (median duration of intubation 12 vs. 3 days, P less than 0.005). A comparison of the preoperative pulmonary function with that determined at least 6 months after the operation showed that only vital capacity (VC) and total lung capacity (TLC) were significantly (P less than 0.05) reduced following the operation, but not to a clinically relevant degree (VC-6%, TLC-7%).

Adolescent↗
PubMed2004

Localized compliance of small airways in excised rat lungs using microfocal X-ray computed tomography.

Airway compliance is a key factor in understanding lung mechanics and is used as a clinical diagnostic index. Understanding such mechanics in small airways physiologically and clinically is critical. We have determined the "morphometric change" and "localized compliance" of small airways under "near"-physiological conditions; namely, the airways were embedded in parenchyma without dehydration and fixation. Previously, we developed a two-step method to visualize small airways in detail by staining the lung tissue with a radiopaque solution and then visualizing the tissue with a cone-beam microfocal X-ray computed tomography system (Sera et al. J Biomech 36: 1587-1594, 2003). In this study, we used this technique to analyze changes in diameter and length of the same small airways ( approximately 150 microm ID) and then evaluated the localized compliance as a function of airway generation (Z). For smaller (<300-microm-diameter) airways, diameter was 36% larger at end-tidal inspiration and 89% larger at total lung capacity; length was 18% larger at end-tidal inspiration and 43% larger at total lung capacity than at functional residual capacity. Diameter, especially at smaller airways, did not behave linearly with V(1/3) (where V is volume). With increasing lung pressure, diameter changed dramatically at a particular pressure and length changed approximately linearly during inflation and deflation. Percentage of airway volume for smaller airways did not behave linearly with that of lung volume. Smaller airways were generally more compliant than larger airways with increasing Z and exhibited hysteresis in their diameter behavior. Airways at higher Z deformed at a lower pressure than those at lower Z. These results indicated that smaller airways did not behave homogeneously.

Animals↗
PubMed2000

Effects of birthweight and oxygen supplementation on lung function in late childhood in children of very low birth weight.

Impaired respiratory function has been found frequently in ex-premature children, but it is unclear which specific factors influence this impairment the most. The aim of this study was to determine the importance of the contributions of birth weight, gestational age, neonatal respiratory disease, and its treatment on subsequent childhood lung function at age 11 years in a cohort of children of very low birth weight (VLBW; </=1,500 g). Detailed clinical histories were recorded, and lung function was measured in 60% (102 children) of surviving VLBW infants born 1981/1982, and compared with 82 matched control children (birth weight >2,000 g) of similar age. VLBW children were shorter and lighter than controls (P < 0.0001) at 11 years of age, and had reduced expiratory flows (P < 0.00001) and forced vital capacities (P < 0.001). The residual volume to total lung capacity ratio (RV/TLC ratio) was increased (P < 0.00001), while total lung capacity (TLC) remained unchanged. Those with bronchopulmonary dysplasia (BPD) had the lowest mean expiratory flows. Males had lower expiratory flows than females. On univariate analysis, gestational age by itself accounted for 8.8% of the explained variance in FEV(1) at 11 years of age, but birth weight accounted for 16% on its own; both together accounted for a further 0.2% (16.2%), suggesting that the latter was the dominant factor. On multivariate analysis, the contribution of birth weight and gestational age was small, and the best predictors at 11 years of age, which together explained 43.4% of the total variance in FEV(1), were log days of supplemental oxygen (9.6%) and a reported history of asthma (10.8%). For FEF(25-75), these predictors explained 7.2% and 13.4%, respectively, of the total explained variance of 40.6%. The relation between neonatal oxygen supplementation and childhood FEV(1) was such that up to 20 days of supplemental oxygen had little effect on subsequent FEV(1) at 11 years of age, but each additional week of supplemental oxygen after that time was associated with a progressive reduction in FEV(1) of 3%. These data confirm the significant role of supplemental oxygen in the neonatal period and a history of asthma on the subsequent reduction of expiratory flows in VLBW children. Birth weight was a more important prenatal factor than gestational age, but both were of lesser predictive significance than either supplemental oxygen or a reported history of asthma.

Asthma↗
PubMed2003

Pulmonary function 4 months after coronary artery bypass graft surgery.

The objective of this study was to describe the pulmonary function and pain 4 months after coronary artery bypass graft surgery. Twenty-five male patients performed pulmonary function tests before surgery, on the 4th postoperative day and 4 months after surgery. A severe reduction in pulmonary function was present after surgery. Four months postoperatively, the patients still showed a significant decrease (6-13% of preoperative values) in vital capacity (P<0.001), inspiratory capacity (P<0.001), forced expiratory volume in 1 s (P<0.001) peak expiratory flow rate (P<0.001), functional residual capacity (P=0.05) total lung capacity (P<0.001) and single-breath carbon monoxide diffusing capacity (P<0.01). Residual volume and single-breath carbon monoxide diffusing capacity per litre of alveolar volume had returned to the preoperative level. Four months postoperatively, the median values for sternotomy pain while taking a deep breath was 0.2 and while coughing 0.3 on a 10 cm visual analogue pain scale. In conclusion, a significant restrictive pulmonary impairment persisting up to 4 months into the postoperative period was found after CABG. Measured levels of pain were low and could not explain the impairment.

Aged↗
PubMed1996

Pulmonary function changes in long-term survivors of bone marrow transplantation.

PURPOSE: This study was undertaken to evaluate long-term pulmonary function changes in patients undergoing bone marrow transplantation (BMT), to assess their clinical significance, and to identify factors influencing these changes. METHODS AND MATERIALS: Pulmonary function tests (PFT) were evaluated before and after BMT in 111 adult patients undergoing BMT between 1985 and 1991. Forced expiratory volume at 1 s (FEV1), forced vital capacity (FVC), diffusing capacity (DLCO), and total lung capacity (TLC) were evaluated. One hundred and three patients (92.8%) received total body irradiation (TBI) to a total dose of 14 Gy in nine equal fractions. The lung dose was restricted to < 6.5 Gy in 95% of patients with partial transmission lung shielding. Seventy-eight percent of patients had acute graft-versus-host disease (aGVHD), 69% chronic graft-vs.-host disease (cGVHD), and 63% posttransplant pulmonary infection. Effects of GVHD, TBI, radiation dose to the lungs, dose rate of TBI, posttransplant pulmonary infection, Busulfan use for conditioning, age, and history of smoking were evaluated for their influence on pulmonary function. RESULTS: Posttransplant FEV1, FVC, and TLC were lower than pretransplant values (p < 0.05) at 6 months and 1 year posttransplant with subsequent recovery. DLCO was significantly lower at all posttransplant intervals. FEV1 did not fall significantly in patients without acute or chronic GVHD and recovered earlier than in patients without posttransplant pulmonary infection. Recovery of FVC, TLC, and DLCO was also delayed in patients with acute and chronic GVHD and posttransplant pulmonary infection. Multiple regression analysis revealed an association between a higher radiation dose to the lungs, and decreased FVC at 2 years (p = 0.01). Progressive obstructive pulmonary disease was not observed. CONCLUSION: An initial decline in PFTs with subsequent recovery was observed. Factors associated with delayed recovery and incomplete recovery of PFTs were GVHD, posttransplant pulmonary infection, and higher radiation dose to the lungs. The conditioning regimen used at Medical College of Wisconsin, including relatively high TBI doses with partial transmission pulmonary shielding, appears to be well tolerated by the lungs in long-term survivors. No progressive decline in PFTs or symptomatic decline in pulmonary function was observed during the time interval studied.

Acute Disease↗
PubMed1975

Static recoil of the lungs and static compliance in healthy children.

The static lung compliance was studied in 57 healthy children, 6 to 14 years old. A new method called ' end-expiratory-compliane' (C1 EE) has been developed and the results were compared to the data obtained from ZAPLETAL et al. with the 'static pressure-volume' curves technique. The advantages of the method are discussed. The static lung compliance of children increases with height. Static lung compliance value is greater than dynamic lung compliance. This difference is discussed. Static recoil pressure of the lung was measured by the oesophageal baloon technique at so-called 'zero volume' of air in the balloon. At functional residual capacity (FRC), i.e. 41-44% total lung capacity (TLC), static recoil pressure is negative in all children, according to this technique. The taller the child, the more negative is the intrathoracic pressure at the same lung volume in percent of TLC, the slopes of the P/V curve being significantly different in younger and in older children. These data are compared to those observed in adults. The elastic properties of the lungs in younger children seem to be similar to those in older adults as a result of lung growth and aging, which successively influence the elastic behaviour of the lung tissue. The influence of the experimental conditions (intra-oesophageal ballon) on the data collected in children is emphasized.

Adolescent↗
PubMed1994

Diffusing capacity dependent on lung volume and age in normal subjects.

In this study we determined reference values of total diffusing capacity of carbon monoxide (DLCO) and DLCO per liter alveolar volume (DLCO/VA) at total lung capacity (TLC) and at lung volumes below TLC in sitting position. In 55 healthy nonsmoking volunteers (20-85 yr old), we determined reference values at TLC level in which age was the only parameter. In a subgroup (n = 16) these references did not change by correction for normal variability in hemoglobin concentration. In all volunteers DLCO decreased and DLCO/VA increased with decreasing VA. The increase in DLCO/VA was linear and less in older subjects. We derived equations to calculate reference values of DLCO/VA for lung volumes at and below TLC with two methods: 1) "random coefficients linear" model, which calculates the reference values directly, and 2) a conversion method, which calculates DLCO/VA for lower VA levels from reference values at TLC. An advantage of the conversion method is the suitability of DLCO/VA reference values at TLC of other populations. A disadvantage is the greater standard deviation of these reference values compared with those obtained by the random coefficients linear method. DLCO can be found by multiplying DLCO/VA with VA.

Adult↗
PubMed1998

Respiratory work in elastase treated hamsters.

Biomechanical adaptations of the diaphragm in the hamster model of emphysema are similar to those observed in skeletal muscle with exercise training. The aim of this study was to evaluate whether the dynamic pressure-volume (PV) work of breathing in hamsters with elastase-induced emphysema may contribute to these adaptations. PV work in elastase treated animals was compared to healthy controls. The studies were performed in adult hamsters 14-16 months following intratracheal administration of elastase (elastase treated group, ET) or saline (control group, CTL). Airway and esophageal pressures and air flows were measured during spontaneous breathing in anesthetized, supine animals. Pulmonary work (WL) was computed from transpulmonary pressures and airflows. Functional residual capacity (FRC) and total lung capacity (TLC; defined as volume at 25 cmH2O) in ET were increased 2 and 1.8 times, respectively, compared with CTL. Averaged tidal volume (VT) and inspiratory flows were comparable between groups. Total work of breathing (WT) normalized per ml VT was not significantly affected with elastase treatment but the pulmonary elastance work (WE) was significantly less in ET animals than controls (0.88 +/- 0.61 g cm(-2) vs. 1.63 +/- 0.32). Pulmonary resistive work was not significantly different between ET and CTL animals. These results suggest that biomechanical adaptations of the diaphragm observed in ET hamsters are caused by mechanisms other than the changes in dynamic mechanical properties of the lung following elastase treatment.

Animals↗
PubMed1991

Influence of weight on pulmonary function in the adult guinea pig.

We examined a group of 63 adult female Hartley strain guinea pigs with weight ranging from 625 to 1,200 g in order to ascertain whether pulmonary function tests including lung volumes, pressure-volume curves, and flow-volume curves were affected by the weight of the animal. We found that there was a weight effect on total lung capacity, vital capacity, residual volume, and the forced expiratory flow between 25 and 75% of total lung capacity, although there was no effect on other parameters of airflow. Flow-volume curves for each animal could be accurately fitted to a mathematical equation, and this equation did not vary with the animals' weight. Pressure-volume curves were affected by animal weight, but could be accurately fitted to a weight-corrected equation. We conclude that when pulmonary function tests are performed on adult guinea pigs, lung volumes may be altered in proportion to the weight of the animal. When pressure-volume or flow-volume curves are being considered, although weight can either be corrected for or has no bearing on the shape of the curve, there is a large between-animal variation, and it may be necessary to use large experimental groups when it is impossible to use the same animal as its own control.

Animals↗
PubMed1991

What factors explain racial differences in lung volumes?

In order to examine the physical characteristics that may determine racial differences in lung volumes, we studied healthy, nonsmoking Caucasian, Chinese and Indian males of similar ages (range 18-51 yrs). We measured spirometric function, flow volume curves, lung volumes, inspiratory and expiratory muscle pressures, alveolar distensibility and diffusing capacity, together with height, weight and fat free mass. Chest shape was measured using radiographs. The mean total lung capacity and vital capacity in the Caucasian group, expressed as percentage predicted, were 5 and 10% higher than in the Chinese group and 17 and 20% higher than in the Indian group. Chinese values for these measurements were 12 and 10% greater than Indian. We found that Caucasians had higher fat free masses, higher inspiratory and expiratory muscle pressures and wider chests than the other races. The Caucasians and Chinese had longer chests than the Indians. There was no difference in alveolar distensibility or in the diffusion coefficient between the groups. These findings suggest that Caucasians have larger lung volumes than Chinese and Indians because they have increased numbers of alveoli and physically larger chest cavities, and not because of greater alveolar distensibility. Chest dimensions, together with height and race explained 90% of the variation in forced vital capacity and 86% of the variation in total lung capacity. Height multiplied by fat free mass, a "physique factor", previously suggested as the best predictive factor for forced vital capacity in Caucasians, did not account for much of the variation in forced vital capacity between Caucasians and Indians, presumably because it takes no account of differences in chest dimensions.

Adolescent↗
PubMed1977

Lung elasticity and airway dynamics in Peruvian natives to high altitude.

To evaluate the role of genetic and environmental factors in the genesis of large lungs in high-altitude natives, we measured forced vital capacity (FVC), static lung pressure-volume characteristics and maximum expiratory flow-volume loops in 17- to 20-yr-old Peruvian natives to 3,850 m (highlanders) and 800 m (lowlanders). Forced vital capacity was 5.11 +/- 0.64 liters in highlanders, 116 +/- 11% of predicted; and 3.73 +/- 0.32 liters in lowlanders, 84 +/- 7% of predicted. Lung elastic recoil at functional residual capacity and at total lung capacity, and size-corrected pressure volume curves were similar in the two groups. Despite the larger volumes in highlanders, density-corrected maximum flow rates were similar in highlanders and lowlanders, and flow expressed in FVC'S-S-1 was less in highlanders. Upstream conductance at 50% FVC expressed in fvc's-s-1-cmH2O was 0.094 +/- 0.023 in highlanders vs. 0.147 +/- 0.050 in lowlanders. Flow rates did not change in sojourners to altitude, suggesting that the lower values of highlanders were due to anatomic factors. These findings suggest that airways, which form in fetal life, do not participate in adaptation to altitude, and that the large lungs of highlanders result from postnatal environmental hypoxic stimulation of lung growth. Our results illustrate the importance of "dysynaptic" lung growth in determining patterns of adult lung function.

Acclimatization↗
PubMed1990

[Comparison of the protective action of 2 respiratory protective devices in farmers with farmer's lung].

With the aid of provocative challenges with hay in patients suffering from farmer's lung, a comparison of the protective effectiveness of the Airstream Helmet (main filter P2) and of the Sundström Mask (main filter P3) was undertaken. A total of 42 farmers were admitted to the study. In 14, as indicated by an expertise, a workplace-related provocative challenge by the farmers' own hay was carried out and was shown to be positive with respect to the presence of farmer's lung disease. In 28 farmers in whom an inhalative provocative challenge with hay had been demonstrated to be positive, inhalative provocative challenges were again performed using the farmers' own hay while the farmers were wearing protective respirators--14 with the Airstream Helmet, (main filter P2) and 14 with the Sundström Mask (main filter P3). When the respirator was not worn, a statistically significant increase in the number of leukocytes and temperature vis-a-vis the baseline values was observed. Partial oxygen pressure, vital capacity, total lung capacity and DCO, all showed a statistically significant decrease as compared with the baseline figures. The provocative challenges performed while the subjects were wearing the respirators also revealed a statistically significant increase in the number of leukocytes and in temperature, which, however, was statistically significantly smaller than that induced by provocation without the respirator. A similar pattern of behaviour was also found in the decrease in vital capacity, oxygen partial pressure, total lung capacity and DCO. No statistically significant differences were observed between the provocation figures obtained with the Airstream Helmet as compared with those obtained with the Sundström Mask.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchial Provocation Tests↗
PubMed1980

Low lung capacity and hypoxemia in children with thalassemia major.

We evaluated lung function in 17 children with thalassemia major in stable condition receiving blood transfusions at regular intervals and subcutaneous desferoxamine daily. Total lung capacity (TLC) was below 2 SD of normal values for height in 7 of the 17 children and arterialized capillary PO2 was below the normal range in 15. We studied lung mechanics in 4 children with reduced TLC and found static and dynamic compliance below 2 SD of normal values for height in 3, and lung recoil at TLC above normal values and specific upstream conductance (Gus/TLC) above 2 SD of normal values in all 4. Although these alterations in lung function have been described in patients with pulmonary fibrosis, we found no fibrosis in autopsy specimens of lung from 8 other patients with thalassemia. The rate constant of carbon monoxide diffusion (kCO) was above the predicted mean in 14 of 15 children. These findings can be explained by a decrease in the growth of airspace relative to the vascular bed and major airways during childhood.

Adolescent↗
PubMed1984

Changes in lung, airway, and chest wall function in boys and girls between 8 and 12 yr.

Maximum expiratory flows, maximum inspiratory and expiratory pressures, and lung volumes were measured in 248 8-yr-old and 215 12-yr-old healthy school children. Eight-year-old girls had smaller total lung capacity but higher volume-corrected expiratory flows than boys. Maximum expiratory flow and total lung capacity increased more in girls than in boys between 8 and 12 yr. Girls had a greater increase in residual volume (0.23 liter for girls, 0.16 liter for boys) as well as lower maximum expiratory and inspiratory pressures (P less than 0.001). Girls have smaller lung volumes than boys, so one would expect smaller airways in girls, but girls generate greater flows, indicating that their airways are possibly wider than those of boys. There is also evidence of unequal growth of the airways and air spaces between 8 and 12 yr. Chest wall development appears less in girls than boys and the difference becomes more marked at 12 yr.

Body Height↗