Maximum expiratory flow rates in induced bronchoconstriction in man.

We evaluated changes of maximum expiratory flow-volume (MEFV) curves and of partial expiratory flow-volume (PEFV) curves caused by bronchoconstrictor drugs and dust, and compared these to the reverse changes induced by a bronchodilator drug in previously bronchoconstricted subjects. Measurements of maximum flow at constant lung inflation (i.e. liters thoracic gas volume) showed larger changes, both after constriction and after dilation, than measurements of peak expiratory flow rate, 1 sec forced expiratory volume and the slope of the effort-independent portion of MEFV curves. Changes of flow rates on PEFV curves (made after inspiration to mid-vital capacity) were usually larger than those of flow rates on MEFV curves (made after inspiration to total lung capacity). The decreased maximum flow rates after constrictor agents are not caused by changes in lung static recoil force and are attributed to narrowing of small airways, i.e., airways which are uncompressed during forced expirations. Changes of maximum expiratory flow rates at constant lung inflation (e.g. 60% of the control total lung capacity) provide an objective and sensitive measurement of changes in airway caliber which remains valid if total lung capacity is altered during treatment.

Pulmonary function in children with atrial septal defect before and after heart surgery.

OBJECTIVE: To test the effect of heart disease and heart surgery on lung function. DESIGN: A pulmonary function study of children undergoing surgery for atrial septal defect (ASD). SETTINGS: University hospital. PATIENTS: 26 children tested before surgery (at mean (SD) age 11.8 (3.8) years) and 24 patients tested 1.8 (0.2) years after surgical correction. METHODS: Lung volumes, lung elasticity, and airway patency indices were measured using standard techniques. RESULTS: Before surgery: pulmonary function test abnormalities were found in 18 of the 26 patients. Stiff lung was found in 12, lung hyperinflation in five, and indices of decreased airway patency in four. Total lung capacity decreased in only two patients. After surgery: pulmonary function test abnormalities were found in 12 of the 24 patients (informed consent not given for two patients). Stiff lung was detected in nine and indices of peripheral airway obstruction in four. Mean values of specific airway conductance and peak expiratory flow were all normal. Lung hyperinflation was found only in one of 24 patients. No correlation between perioperative events and pulmonary function test data was found. CONCLUSIONS: Pulmonary function test abnormalities persist in half the patients almost two years after surgery for ASD. A decrease in the total frequency of pulmonary function test abnormalities (in 19% of the patients), with a decrease in stiff lung in 8% and lung hyperinflation in 15%, was not significant. Impairment of lung function related to ASD is associated with the disease itself rather than the surgical procedure.

Forced expiratory parameters in healthy preschool children (3-6 years of age).

In a group of 173 healthy preschool children 3-6 years of age (body height, 90-130 cm; 102 boys and 71 girls) out of total 279 children examined, maximum expiratory flow-volume (MEFV) curves were recorded in cross-sectional measurements. The majority (62%) of preschool children were able to generate an MEFV curve as correctly as older children. From the curves, maximum expiratory flows at 25%, 50%, and 75 % of vital capacity (MEF(25), MEF(50), and MEF(75)), peak expiratory flow (PEF), forced expiratory volume in 1 sec (FEV(1)), forced vital capacity (FVC), and area delineated by MEFV curve (A(ex)) were obtained. The purpose of the study was to establish reference values of forced expiratory parameters in preschool children suitable for assessment of lung function abnormalities in respiratory preschool children. The values of the studied parameters increased nonlinearly and correlated significantly with body height (P < 0.0001); the correlation was much lower with age. A simple power regression equation was calculated for the relationship between each parameter and body height. A best-fit regression equation relating functional parameters and body height was a power function. Based on the obtained regression equations with upper and lower limits, we prepared tables listing reference values of forced expiratory parameters in healthy Caucasian preschool children, against which patients can be compared. No statistically significant gender differences were observed for MEF(25), MEF(50), MEF(75), PEF, FEV(1), FVC, and A(ex) by extrapolation. The reference values were close to those obtained in our older children. A decline of the ratios PEF/FVC, FEV(1)/FVC and MEF/FVC with increasing body height suggested more patent airways in younger and smaller preschool children.

Nasal airflow and resistance measured by active anterior rhinomanometry in healthy children and adolescents.

Rhinomanometry allows objective assessment of nasal patency in pediatric patients with nasal and other respiratory problems. However, no reliable reference values are available in the pediatric age group. We measured nasal inspiratory airflow and nasal inspiratory resistance of the right and left nostrils (V'nar, V'nal, Rnar, and Rnal) and total nasal inspiratory flow and resistance (V'na and Rna) at a transnasal pressure of 150 Pa during quiet breathing in healthy children with a closed mouth by using active anterior rhinomanometry. Cross-sectional measurements were done in 192 healthy Caucasian children and adolescents free of nasal or other respiratory diseases (age, 2-19 years; body height, 94-190 cm; 95 boys and 97 girls). The values of V'na, V'nar, and V'nal increased significantly with an increase of body height or age (P<0.0001). Rna, Rnar, and Rnal significantly decreased with an increase of body height and age (P<0.0001). No significant statistical differences were found between boys and girls (P=0.11) or between right and left nostrils (P=0.07). V'nar and Rnar comprised 50.1%, and V'nal and Rnal 49.9%, of total V'na and Rna, respectively. Best-fit regression equations relating rhinomanometric parameters and body height or age were power functions. We obtained reference regression equations with upper and lower limits, and prepared tables listing reference (normal) values of rhinomanometric parameters in healthy pediatric Caucasian patients, against which patients with nasal obstruction can be compared.

Lung function in children and adolescents with tetralogy of Fallot after intracardiac repair.

We studied lung function in 41 patients, aged 6-27 years, 1-5 years after intracardiac surgical repair (ICR) of tetralogy of Fallot (TOF) and about 5 years after the establishment of the Pediatric Cardiac Center in Prague. The measurements included vital capacity (VC), total lung capacity (TLC), functional residual capacity (FRC), residual volume (RV), forced expiratory flows (FEF), specific airway conductance (SGaw), lung recoil pressure (Pst), and specific static lung compliance (SC1st). Single or multiple abnormal lung function parameters were found in 83% of patients. Lung function was not related to shunting operations prior to ICR, hemoglobin concentration, and hematocrit, and had no specific pattern. Pst at 100% TLC and 90% TLC declined with increasing age at ICR and at lung function testing, while SC1st rose, as did the ratio FRC/TLC. Fifteen patients were studied before and after surgery. Single or multiple lung function tests were abnormal in 93% before and in 84% after ICR. After ICR the ratios FRC/TLC and also RV/TLC, FEF at 25% VC, and FEF at 60% TLC were less frequently abnormal, while Pst at 100% TLC and at 90% TLC, as well as SGaw and TLC, were more frequently abnormal after ICR. The results indicated a regression of smaller airway obstruction and lung hyperinflation after ICR. The evolution of abnormally compliant (emphysematous) lungs with growth of the patients might be a sign of permanent sequelae of early lung damage from abnormal pulmonary hemodynamics.

Lung recoil and the determination of airflow limitation in cystic fibrosis and asthma.

A reduction of lung recoil pressure could aggravate any airflow limitation that might be present in patients with cystic fibrosis (CF) or asthma. In a group of 22 children and young adults (8 with cystic fibrosis, 8 with asymptomatic asthma, and 6 healthy controls) aged 8-24 years, lung recoil pressure (Pst) at 100%, 90%, and 60% of TLC and static lung compliance (Cst) were measured using an esophageal balloon. The indices of airflow limitation, including maximal expiratory flow at 25% VC (Vmax25), forced expiratory volume in 1 second (FEV1), and specific airway conductance (sGaw), were also measured. In all patients, Vmax25 was reduced, the airway obstruction being more pronounced in patients with CF. Pst was reduced in CF and asthma, again more in the patients with CF. Cst was normal in both groups because the pressure volume curve was shifted up and to the left. There were significant correlations between Pst at 60%, 90%, and 100% of TLC and both Vmax25 and FEV1 (P < 0.01). sGaw correlated with Pst90 and Pst60 (r = 0.47 and 0.53, respectively; P < 0.05 for both). No correlation was found between Cst and Pst at any lung volume. No correlations were observed between Cst and Vmax25, FEV1, or sGaw. These results suggest that loss of elastic lung recoil pressure is a factor in airflow limitation of children and young adults with CF or asthma.

Lung function in children and adolescents with idiopathic interstitial pulmonary fibrosis.

Lung function of 65 patients who had idiopathic interstitial pulmonary fibrosis (IIPF) that had been treated with prednisone was evaluated by tests of ventilatory function, lung mechanics, and gas exchange at rest and during exercise. Ages on initial investigation ranged from 5 to 20 years. In 35 of 65 patients the studies were repeated an average of four times over a period of 1 to 9 years. Results of the first testing were as follows: vital capacity (VC)-significantly reduced in all patients; inspiratory capacity (IC)-significantly reduced in all patients; total lung capacity (TLC)-reduced in 91%; functional residual capacity (FRC)-reduced in 31%; residual volume (RV)-reduced in 6%; elastic recoil of the lungs (Pstl)-significantly increased in 97% at 100% TLC, significantly increased in 52% at 90% TLC, reduced in 68% at 60% TLC; 7) static compliance (Cst)-reduced in 83%; 8) dynamic compliance (Cdyn)-reduced in 88%; 9) specific airway conductance at FRC level (Gaw/TGVex)-significantly increased in 50%; 10) maximum expiratory flow rates at 60% TLC (Vmax 60% TLC, in TLC/s)-significantly reduced in 33%; 11) upstream airway conductance (Gus 60% TLC, in TLC/s/cm H2O)-reduced in 32%; 12) diffusing capacity of the lungs for carbon monoxide (DLco) related to body-surface area-abnormal in 58% (when corrected for lung size, i.e., DLco/TLC, abnormal in only 8%); 13) PaO2 at rest and after 6 minutes submaximal exercise-reduced in 25% and 63%, respectively. Changes in lung function that occurred with growth were assessed in terms of percentages of predicted values. Results showed that the VC and IC remained significantly reduced. An actual reduction of TLC, FRC, RV, breathing frequency, DLCO, and Pstl at 100% and 90% TLC was observed. Increases were seen in Pstl at 60% TLC, Gaw/TGVex, Vmax, and Cst. Indices of lung elasticity suggested that regions of fibrosis and emphysema had become present. Smaller patients were also noted to have stiffer lungs.

Airway function tests and vocal cord paralysis in lung transplant recipients.

Maximum expiratory and inspiratory flow-volume (MEFV, MIFV) curves, specific airway conductance (sGaw), and flexible fiberoptic laryngoscopy were examined in 8 pediatric lung transplant recipients with vocal cord paralysis (VCP). Six were heart-lung (H-L) and 2 double-lung (D-L) recipients, 7 had left VCP, and 1 had right VCP. Based on the pulmonary function tests (PFT), 2 subgroups could be distinguished in the 8 recipients with VCP. Group A (5/8 recipients; mean age, 13 +/- 3.4 years; mean height, 144.3 +/- 12.3 cm) had significantly reduced specific airway conductance (sGaw; < 2 SD from predicted) and normal MEF25, MEF50, peak expiratory flow (PEF), forced expiratory volume in 1 second (FEV1), and %FEV1/forced vital capacity (FVC); this pattern suggested variable extrathoracic airway obstruction. PIF was normal in 4/5 and reduced in 1/5 of these recipients. Group B (3/8 recipients with VCP; mean age, 17 +/- 2.4 years; mean height, 156.3 +/- 12.0 cm) had significantly reduced sGaw, MEF25, MEF50, PEF, FEV1, and %FEV1/FVC, implying primarily small airway obstruction. These recipients had bronchiolitis obliterans. The results suggest that a pattern of reduced sGaw and normal MEFs, PEF, FEV1, and PIF should raise the possibility of VCP in patients after lung transplantation. sGaw is more sensitive than PIF and PEF in identifying airway obstruction due to VCP, and should be routinely included in the follow-up evaluation of lung transplant recipients.

Lung function in atrial septal defect after heart surgery.

Lung volume, indices of lung elasticity and airway patency were measured in 74 patients, 9-21 yr old (15.0 +/- 2.5 yr) with atrial septal defect (secundum type) from 2-11 (5.1 +/- 2.5) yr after successful surgical correction. Clinical condition in all patients was classified as excellent. Heart surgery was performed at the age of 4-14.8 (9.9 +/- 3.0) yr. Lung function abnormalities were found in 35 (47.3%) patients. Lung recoil pressure was significantly increased in 24 (32.4%) patients. The mean value of lung recoil pressure at 100% of total lung capacity reached 123 +/- 31% of the predicted value (P < 0.0001). Specific static compliance was within normal limits. Specific airway conductance was significantly reduced in 13 (17.6%) patients. Maximum expiratory flow at 25% of vital capacity was significantly reduced in 4 (5.4%) patients. Static lung volumes did not differ from reference values. Since various abnormalities of lung function tests (most frequently the tests suggested increased lung stiffness and obstruction of larger airways) were revealed in almost half of the studied children and adolescents after successful surgery for atrial septal defect, we propose to carry out lung function tests routinely as another criterion of health conditions in these patients.

Lung function in simple complete transposition after intracardiac repair.

Pulmonary function was measured in 35 patients (mean age 11.6 years) with simple complete transposition 4.4 years after intracardiac repair. A disturbance in the lung function (greater than 2 SD from the normal value) was found in 88% of the patients. A marked increase in static recoil pressure (P less than 0.001) was most frequent (in 66%). Static lung compliance was only 75.1% of the predicted values. Values of mean vital and total lung capacity were decreased (P less than 0.01 and 0.001). Residual volume, the ratios of functional residual versus total lung capacity and residual volume versus total capacity were all increased. The signs of decreased patency of the airways were found in only 4 patients. A negative correlation was detected between the indices of lung stiffness and the age of assessment of lung function. A positive correlation was found between the ratios between functional residual and total capacity and pulmonary blood flow. No other correlation between lung function data and pulmonary arterial pressure or flow was proved. Increased lung stiffness, restriction of lung volume and hyperinflation could influence unfavorably the long-term results in successfully treated patients with simple complete transposition.

[Cystic fibrosis--a disease of adolescents and adults?]. / Cystická fibróza--nemoc dospívajících a dospelých?

BACKGROUND: Cystic fibrosis (CF) is no longer a childhood disease. Since the identification of the gene in 1989 research has made advances and changed views on the pathogenesis, diagnosis and treatment. The objective of the present work is to make doctors treating adult patients familiar with modern therapeutic methods and their value. METHODS AND RESULTS: In the CF Centre of the Faculty Hospital in Prague Motol 349 patients are followed up on a long-term basis, incl. 95 who died since 1985. Hundred and twenty six (36.1%) patients survived to the age of 18 years, of those 41 died and 85 patients live. Comparison of semilongitudinal data of a group of 83 patients born before 1975 whose treatment during childhood and puberty was inadequate and 196 patients born in 1976-90 treated by modern methods proved the great effect of treatment on the course and prognosis of the disease. The median age at death increased during from 12.2 years in 1985-90 to 18.8 years in 1991-1998 (p = 0.004). The nutritional status of adult patients is satisfactory in 40.4%, poor in 33.3% and marginal in 26.3%. A normal pulmonary function was recorded in 17.5%, 22.8% are severely affected, the majority of patients (59.7%) has values within 40 to 80% of normal levels. CONCLUSIONS: Modern intensive treatment improved the prognosis and quality of live in patients with CF. Critical deterioration of the clinical condition shifted to the threshold of adult age. It is therefore essential that doctors treating such patients should be familiar with this issue.

[Bronchial hyperreactivity in pediatric and adolescent asthmatics and healthy children]. / Zkusenosti s vysetrováním bronchiální hyperreaktivity u detských a mladistvých astmatiku a zdravých detí.

The investigation of bronchial hyperreactivity (b.h.) represents the basic diagnostic test in asthmatics. In 515 asymptomatic pediatric and adolescent asthmatics (age 6-23 years) divided into various subgroups according to the study purposes, b.h. as an induced airway obstruction was assessed after inhalations of a single dose of acetylcholine (3 mg), histamine (3 mg), hypotonic and hypertonic solutions with jet nebulizer. B.h. was also studied following inhalations of distilled and mineral water, physiologic solution with ultrasonic nebulizer, and 5 min. free running outdoors. The induced airway obstruction was assessed by parameters measured from maximum expiratory flow-volume curve. The most potent stimuli were the inhaled acetylcholine (3 mg) and 5 min. free running outdoors. By the latter two tests similar incidence and magnitude of b.h. were revealed in our asthmatics without airway obstruction as well as with a mild obstruction (MEF50 and MEF25 below lower limits of predicted before both tests). For both tests (acetylcholine and 5 min. free running), recommended in practice, were given the expected limits of lung function parameters before starting the tests. The values of the parameters before the onset of provocation tests were unreliable predictors of the induced airway obstruction in our asthmatics. B. h. was also assessed in 426 healthy 9-years old children by inhalation of 1% carbachol (mean dose: 2.57 +/- 0.7 mg). Various lung function parameters showed different incidence of b.h. in the latter children. Both values of one- second vital capacity and respiratory resistance (interruption technique) revealed b.h. in 46% of our healthy children (decline of parameters more than 20%). Other parameters measured, except peak expiratory flow, proved b.h. more frequently. In the article the problems of respiratory resistance measured by interruption technique and higher incidence of b.h. in the studied healthy children are outlined.

[Exercise-induced airway obstruction in asthmatic children and adolescents]. / Zkusenosti s vysetrováním ponámahové obstrukce dýchacích cest u detských a mladistvých astmatiku.

In 115 asymptomatic asthmatic children and adolescents (age 6-18 years) there was studied the magnitude of airway obstruction, induced by various physical efforts and assessed from the recording of maximum expiratory flow-volume curves and in some patients by "specific" airway conductance measurement in a body plethysmograph. The effects of 5 minutes free running outdoors, 5 minutes of exercise on a bicycle ergometer (2 watts/kg of body weight), routine swimming training in swimming pool and of forced expiration maneuver on the magnitude of airway obstruction were assessed. The most frequent and largest degree of airway obstruction was observed after 5 min. free running outdoors (heart rate after running 160-200/min). The obstruction was revealed in 80-100% asthmatics in various groups. The chosen lung function parameters showed exercise-induced airway obstruction in the same patients in various proportions as well as the magnitude of the obstruction. Following free running outdoors the values of maximum expiratory flow at 25% of vital capacity and "specific" airway conductance were most reduced. Spontaneous retreat of obstruction was observed in the course of 2 hours. The physical exercise on a bicycle ergometer was a small stimulus in inducing of airway obstruction. The swimming in a pool did not provoke any obstruction. In 10% of our asthmatics airway obstruction was observed following forced expiration maneuver. Airway obstruction induced by 5 minutes free running outdoors and assessed best by flow-volume curves appeared as a suitable test in the assessment of airway hyperresponsiveness.

[Prevention of post-exertion airway obstruction in children and adolescents with bronchial asthma]. / Moznosti prevence pozátezové obstrukce dýchacích cest u detí a mladistvých s bronchiálním astmatem.

In 86 asthmatics (age 8-16 years), divided into several groups, the protective effects of pharmacological and non-pharmacological agents on the exercise-induced airway obstruction (e.i.a.o.) by 5 minutes free running were studied. There were studied the preventive inhalations of bronchodilators, i.e. fenoterol (0.2 mg), ipratropium-bromide (0.06 mg) and both combined of 0.15 mg of fenoterol and 0.06 mg of ipratropium-bromide on the exercise-induced airway obstruction. The protective effects of breathing through nose as well as the effect of the temperature in the surrounding environment on the e.i.a.o. were studied too. The exercise-induced airway obstruction was assessed on the basis of parameters measured from maximum expiratory flow-volume curves. Maximum expiratory flow at 25% of vital capacity was most sensitive in the assessment of e.i.a.o. The studied bronchodilators protected all patients against e.i.a.o. The textile face mask (surgical mask) put on the nose and mouth during 5 min. free running outdoors and in a closed room protected some asthmatics completely against e.i.a.o. or reduced substantially e.i.a.o. in others. The nose breathing had a similar effect on e.i.a.o. as the textile face mask. The surrounding temperature of air was not decisive in the induction of post-exercise airway obstruction. Non-pharmacological agents ought to be thus more included among the therapeutical means in pediatric and adolescent asthmatics.

[Bronchomotor tests in childhood]. / Bronchomotorické testy v detském veku.

The authors present a review of bronchoconstriction and bronchodilation tests which can be used in the diagnosis of respiratory diseases in children. Basic procedures and principles of evaluation are given.

[The effect of a high-altitude climate on the function of the respiratory system in children with asthma]. / Vliv vysokohorského klimatu na funkci dýchacího ústrojí u detských astmatiku.

In 108 asthmatic children (age 6-15 years) an effect of the 6-8 weeks stay in the High Tatra mountains (Children's Lung Institute, Dolný Smokovec) on lung function was studied in the years of 1985-1988. The patients consisted of groups followed-up in different periods of the latter years. Indications for the stay was airway obstruction (a.o.) in symptom-free period or bronchial hyperreactivity (b.h.) before starting the stay. The effect of climate on a.o. and b.h. was assessed from the parameters, measured from maximum expiratory flow-volume (MEFV) curves. Mean MEFV curves and their areas were considered as indices of the climate effect on a.o. and b.h. in the studied groups of asthmatics during the stay in the Institute. B.h. was assessed according to the induced a.o. after 5 min. free running outdoors. Mean MEFV curves and their areas did not differ significantly at the start and end of the stay in this high mountains climate. However, the MEFV curves significantly differed after the induced a.o. by 5 min. free running at the start and end of this climate therapy. The descendent parts and areas under the curves were reduced much less after the induced a.o. during and the end of stay than at the start of stay. They proved a decrease of bronchial hyperreactivity in all studied groups of asthmatics in the climate of High Tatra. The degree of bronchial hyperreactivity, tested as a magnitude of a.o. following 5 min. free running outdoors, on the basis of parameters from MEFV curves, appeared as an objective measure of climate therapy effect on lung function in our asthmatic children.

[Surgical treatment of pectus excavatum and pectus carinatum]. / Chirurgické lécení pectus excavatum a pectus carinatum.

The authors present their experience with surgery of deformities of the chest wall in childhood. In the course of 1986 to 1992 they operated 93 children with the diagnosis of pectus excavatum. This number comprised 66 boys and 27 girls. The mean age of the operated children was 10.5 years. During the same period 17 patients (12 boys and 5 girls) were operated on account of pectus carinatum. The mean age of the latter group of patients was 13.5 years. 23% of the patients with a pectus excavatum had before operation mild scoliosis, two patients suffered from severe scoliosis. 76 patients after operation of pectus excavatum were followed up for more than one year after operation. In 44 patients the result was excellent (58%), in 31 patients the result was good. One patient developed a relapse. Fifteen patients after operation for pectus carinatum were followed up for more than one year. In 12 patients (80%) the result of the operation is excellent, in three patients (20%) the result is good. From the group as a whole seven patients had dehiscence of the wound after surgery, four patients developed a seroma in the surgical wound, three patients developed pneumothorax after operation and in one instance an abscess developed in the surgical wound. In the course of 1987 the authors changed the surgical technique in pectus excavatum from Jensen's to Holcomb jun. operation.