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PubMed1975

Lung volumes and closing capacity with continuous positive airway pressure.

Total lung capacity, vital capacity, residual volume, and functional residual capacity were determined by body plethysmography and the single-breath oxygen (SBO2) test was performed at 0, 5, and 11 cm H20 continuous positive airway pressure in healthy, awake, seated, spontaneously breathing subjects. Mean values for the absolute lung volume at which phase IV of the SBO2 test begins (closing capacity) did not change significantly with continous positive airway pressure at 5 or 11 cm H2O. Mean total lung capacity, functional residual capacity, and residual volume increased significantly, and the mean closing volume, the lung volume above residual volume at which phase IV begins, decreased significantly with 11 cm H20 continuous positive airway pressure; differences at 5 cm H20 were not significant. The slope of the alveolar nitrogen plateau (phase III) obtained during the SBO-2 test did not change with continuous positive airway pressure.

Adult↗

PubMed1988

Growth of lung and thorax dimensions during the pubertal growth spurt.

In the follow-up study of adolescents residual volume (RV), vital capacity (VC), closing volume (CV), thorax height and thorax width were measured at six month intervals over a six year period; 149 girls and 477 boys, whose ages ranged between 11.5 and 18.5 yr during the follow-up, were investigated. In healthy subjects and in those with respiratory symptoms the rates of change of thoracic dimensions, as calculated by a robust linear regression technique, were moderately well correlated; the growth rates of RV and VC were only slightly correlated, and both were moderately well correlated with changes in thorax dimensions. Thorax height increased relative to thorax width in boys and girls during the follow-up. In boys, thorax height continued to grow, when standing height and thorax width had attained adult values in girls. Thus the thorax attains a more elongated shape. During the adolescent growth spurt the residual volume as a percentage of total lung capacity (RV%TLC) within subjects increased on average 0.6% per yr, and closing volume as a percentage of vital capacity (CV%VC) decreased on average 0.5% per yr. Both of these changes can be accounted for by decreased thorax compliance and increased outward chest recoil at low lung volumes.

Adolescent↗

PubMed1978

Effects of intravenous histamine on lung mechanics in man after beta-blockade.

In six nonatopic normal subjects, neither intravenous histamine infusion (0.3 mg.kg-1.min-1) nor intravenous propanolol (10 mg) alone produced significant change in pulmonary mechanics. Histamine infusion after propranolol resulted in an increase in pulmonary resistance (RL) from 2.1 +/- 0.41 (mean +/- 1 SE) to 3.3 +/- 0.76 cmH2O./-1.S-1 (P greater than 0.05); maximal flow at 50% total lung capacity (Vmax 50) decreased from 3.6 +/- 0.35 to 2.7 +/- 0.44 l/s (P greater than 0.01). Similar changes in Vmax 50 were observed during partial forced expiratory maneuvers from end-tidal inspiration (PEFV). On 80:20 helium-oxygen mixture Vmax 50 during maximal expiration (MEFV) decreased from 4.9 +/- 0.61 to 3.4 +/- 0.61 l/s (P greater than 0.005) and during PEFV diminished from 4.6 +/- 0.61 to 2.8 +/- 0.46 l/s (P greater than 0.005). Density dependence (deltaVmax 50) decreased significantly (P greater than 0.05) during PEFV but not during MEFV. There were no significant changes in tidal pulmonary compliance, in closing volume and closing capacity (resident gas technique), and in inflation and deflation pressure-volume curves. We conclude that iv histamine in low doses constricts peripheral conducting airways in man but this effect is masked by histamine-induced release of catecholamines from the adrenal glands.

Adult↗

PubMed1988

Respiratory symptoms or signs on the day of the study alter pulmonary function in teenagers.

Pulmonary function variables (forced expiratory flows and vital capacity, static lung volume, alveolar N2 slope, closing volume and closing capacity) were compared in a group of 10-16 year old children with (n = 65) and without (n = 440) symptoms or signs of mild acute respiratory infection ('common cold'). Symptomatic children had a significant impairment of forced expiratory vital capacity and flows, with no change in static volumes, alveolar N2 slopes and closing volumes. The effect was present only in boys (in whom RV/TLC and phase III slope were borderline abnormal), was more evident in older children (13 to 16 years) and was independent of the smoking habits or the presence of chronic respiratory symptoms. The results are in favour of a predominant involvement of upper airways, but signs of lower airways dysfunction are present in boys and in children 13 to 16 years old.

Acute Disease↗

PubMed1981

Significance of small airway tests in middle-aged smokers.

In 54 asymptomatic lifelong nonsmokers and 105 current smokers, all steelworkers 45 to 55 yr of age, we measured several lung function indexes in order to assess the significance of small airway tests, slope of phase III of the N2 single-breath washout (delta N2), and bolus closing volume and closing capacity (CC/TLC). Smokers had all mean indexes significantly different from nonsmokers, with CC/TLC and delta N2 being the most frequently impaired tests. Smokers with small airway disease (abnormal CC/TLC or delta N2) but normal forced expiratory volume in one second (FEV1) vital capacity had a significantly lower FEV1/height3 (p less than 0.001) than subjects without small airway disease. The latter had indexes similar to nonsmokers. Our data suggested that smokers with small airway disease experience a more rapid decline in their FEV1 and thus are more susceptible to long-term smoking than smokers without small airway disease. The later appear to be resistant to tobacco-induced chronic airflow obstruction.

Aging↗

PubMed1990

Predictive value of the single-breath nitrogen test for hospitalization due to respiratory disease.

The relationship between indices of the single-breath nitrogen test (SBNT) measured in 1974 and hospitalization in the 9 year period 1977-1986 was examined in a random population sample of 876 men aged 46-69 years. Men who could not perform acceptable SBNT tracings had an increased risk of hospitalization due to respiratory disease in general. When age and smoking habits were controlled for, slope of phase III was significantly related to hospitalization due to respiratory disease in general and chronic obstructive pulmonary disease (COPD), whereas closing volume and closing capacity were marginally related to hospitalization due to respiratory disease in general but not to hospitalization due to COPD. The relationship between slope of phase III and hospitalization due to COPD remained significant after the forced expiratory volume in 1 sec (FEV1) was controlled for: odds ratio 1.4 per % N2/L (95% confidence interval 1.1-1.7). The effect of the slope of phase III was considered to be clinically insignificant, and we conclude that in a random population sample indices from only 1 SBNT do not provide prognostic information concerning hospitalization in addition to that provided by FEV1.

Aged↗

PubMed1996

Airway closure and reopening assessed by the alveolar capsule oscillation technique.

An alveolar capsule oscillation technique was used to determine 1) the lobe pressure and volume at which airways close and reopen, 2) the effect of expiration rate on closing volume and pressure, 3) the phase in the breathing cycle at which airway closure occurs, and 4) the site of airway closure. Experiments were conducted in excised dog lobes; closure was detected by an abrupt increase in the input impedance of surfacemounted alveolar capsules. Mean transpulmonary pressure (Ptp) at closure was slightly less than zero (Ptp = -2.3 cmH2O); the corresponding mean reopening pressure was Ptp = 14 cmH2O. The expiration rate varied between 1 and 20% of total lobe capacity per second and had no consistent effect on the closing volume and pressure. When lung volume was cycled up to frequencies of 0.2 Hz, closure generally occurred on expiration rather than inspiration. These observations support the conclusion that mechanical collapse, rather than meniscus formation, is the most likely mechanism producing airway closure in normal excised dog lungs. Analysis of measured acoustic impedances and reopening pressures suggests that closure occurs in the most peripheral airways. Reopening during inspiration was often observed to consist of a series of stepwise decreases in capsule impedance, indicating a sequence of opening events.

Airway Resistance↗

PubMed1976

Lung function changes in smokers with normal conventional spirometry.

The comparative ability to detect early abnormalities in smokers by commonly used lung function tests was studied. Sixty-five healthy male nonsmokers served as a reference group and provided standards for 1-sec forced expiratory volume, vital capacity, end-tidal spirometry, spirometric forced mid-and end-expiratory flows, single-breath diffusing capacity, static lung volumes (helium method), and single-breath N2 closing volume measurements, In the present series of 80 male smokers, the measurements of forced mid-expiratory flow and forced end-expiratory flow did not improve the ability of the more conventional indices, 1-sec forced expiratory volume and the ratio of 1-sec forced expiratory volume to vital capacity, to detect obstructive lung disease. In 71 smokers with normal 1-sec forced expiratory volume and ratio of 1-sec forced expiratory volume to vital capacity, the end-tidal spirometry, diffusing capacity, and residual volume indices revealed 14,20, and 21 per cent of abnormalities. respectively. The single-breath N2 closing volume test (Phase IV/vital capacity and slope of Phase III) detected the greatest number of subtle changes in lung function; this was abnormal in 32 per cent of smokers with normal conventional spirometry. In young or light smokers, Phase IV/vital capacity was more frequently increased than the slope of Phase III; an incerse trend was observed in older or heavier smokers. The single-breath N2 closing volume test also provided the greatest number of abnormal results when other indices were impaired in the same subjects.

Adult↗

PubMed1990

Small-airways dysfunction in never smoking asbestos exposed Danish plumbers.

Among 701 Copenhagen plumbers we examined the lung function of 23 never smokers, who had removed asbestos insulation and intermittently been exposed to high levels of asbestos for about 25 years without being exposed to welding fume. The plumbers had significantly lower TLC, MEF25, MEF50, closing volume and closing capacity in comparison to 23 never smoking electricians without asbestos exposure. There was no reduction in TLCO. Pulmonary clearance of aerosolized 99mTc-DTPA was normal indicating that the asbestos had not induced increases in pulmonary epithelial permeability. However, in 11 of the 23 plumbers the 99mTc-DTPA ventilation scintigrams had a slightly irregular and spotty appearance, which together with the results of the lung function tests are suggestive of small airways' dysfunction. None of the subjects had symptoms or clinical signs of lung disease.

Adult↗

PubMed1991

Serum IgE and lung function in workers exposed to phthalic anhydride.

A total of 23 phthalic anhydride (PA)-exposed workers (air levels up to 17 mg/m3) showed significantly (P less than 0.01) more workrelated symptoms in their eyes (48% vs 6%) and nose (39% vs 0) than did 18 unexposed control subjects. Two of the exposed workers had PA-associated asthma. Surprisingly, the control group exhibited significantly (P less than 0.05) more symptoms of nonspecific bronchial hyperreactivity (44% vs 13%). The exposed workers showed significantly higher levels of total serum IgE (medians, 32 vs 15 kIU/l, P less than 0.05), although values for specific IgE against PA did not differ. This may indicate that such exposure can facilitate the entry of common allergens. There was a significant difference in PA-specific IgG [enzyme-linked immunosorbent assay (ELISA) ratios 0.21 vs 0.12; P less than 0.01]. There were no differences in lung function with regard to vital capacity (VC) and forced expiratory volume (FEV1), closing volume expressed as a percentage of VC (CV%), volume of trapped gas (VTG) before and after inhalation of metacholine, or carbon monoxide transfer factor (TLCO), whereas exposed workers displayed significantly higher late expiratory flow rates (MEF50 and MEF25). In a [99mTc]-diethylenetriamine penta-acetate (DTPA) clearance test, there was no difference between exposed subjects and controls. In summary, exposure to PA did not cause subclinical effects of the lungs. Subjects with lower-airway symptoms showed lower FEV1, MEF50, and MEF25 values and higher VTG (after metacholine) than did those without symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1981

Pulmonary atelectasis after anaesthesia: pathophysiology and management.

The pathophysiological basis of pulmonary atelectasis is reviewed and risk factors that enhance lung collapse are discussed. Management strategies to reduce or eliminate risk factors and to prevent collapse are discussed and the rational bases of these strategies are identified. Instability of lung alveoli is a consequence of surface tension and regional differences in alveolar size. The inherent tendency of alveoli to collapse is enhanced by the following risk factors; low lung volume, high closing volume, oxygen therapy, a rapid shallow ventilatory pattern, chronic lung disease, smoking, obesity, postoperative pain following abdominal or thoracic surgery, narcotic induced ventilatory depression, and neurological, neuromuscular, muscular and musculoskeletal diseases associated with mechanical impairment of respiratory function. The primary goal of perioperative respiratory management is prevention of atelectasis. Appropriate management strategies include physiotherapy and delay of elective surgery if substantial improvement in respiratory status can be achieved by specific treatments such as antibiotics, bronchodilators, steroids, and reduction of tobacco use and caloric intake. In selected cases, elective postoperative controlled ventilation may be indicated.

Analgesia↗

PubMed1975

Acute effects of smoking tobacco and a tobacco substitute on lung function in man.

The acute effects on airway function of smoking one cigarette of a tobacco substitute 'New Smoking Material' (NSM), one cigarette of conventional tobacco, and one cigarette containing 70% tobacco and 30% NSM, were studied in 6 healthy nonsmokers and 6 healthy smokers. None of the cigarettes produced any change in three tests of small-airway function (flow-volume curves, closing volume, frequency dependence of compliance). However, smoking either one conventional tobacco cigarette or the 30% NSM/70% tobacco cigarette produced an acute fall in specific airways conductance, of similar degree with both cigarettes, whereas the 100% NSM cigarette produced no such change.

Adolescent↗

PubMed1979

Prediction of postoperative hypoxemia in smokers and non-smokers.

Age, weight, spirometric variables, peak expiratory flow and airway closure assessments were correlated to postoperative gas exchange in 40 cholecystectomized subjects grouped according to smoking history. Pao2 was significantly lower in the smoking group both pre- and postoperatively, but the decrease in Pao2 following operation was of the same magnitude irrespective of smoking history. In non-smokers, the preoperative relationship between expiratory reserve volume and closing volume (ERV-CV) showed the highest correlation to postoperative alveolar-arterial oxygen difference P(A-a)o2 (r = -0.88, P less than 0.001) and to the increase of P(A-a)o2 following operation (r = -0.67, P less than 0.001), whereas age was found to be the best preoperative predictor of postoperative gas exchange in smokers.

Adult↗

PubMed1979

Tantalum inhalation and airway responses.

We studied the effects of tantalum inhalation bronchography on pulmonary function in 14 normal volunteers. Based on the radiographic type of deposition, the subjects were divided into three groups: (1) subjects who deposited tantalum mainly in the trachea, (2) subjects who deposited tantalum in segmental bronchi without radiographic evidence of bronchospasm, and (3) subjects who deposited tantalum in segmental bronchi with radiographic evidence of bronchospasm. Unlike the first two groups, the third group developed a significant but small decrease in the FEV. Airway reactivity as assessed by methacholine challenge did not explain the difference in response to tantalum in the third group. There were no consistent changes in total lung capacity, residual volume, or closing volume in any of the groups. Even though there were falls in FEV and specific conductance in individuals in groups 2 and 3, these changes did not pose any significant clinical risk.

Adult↗

PubMed1975

Changes in small airway function after live attenuated influenza vaccination.

Live, attenuated influenza vaccine was given by intranasal inoculation to 15 young, adult volunteers. Modest symptoms occurred within 3 days of challenge, but the agent was otherwise well tolerated. Hemagglutinin-inhibition antibodies increased in 9 of the 12 subjects whose initial volumes, but closing volume did not change. These changes in airflow reverted to previous levels after 1 week. On a second challenge 2 weeks after the first, symptoms were far less frequent, and no changes in airflow were detected. We conclude that this agent is biologically active and that the airflow changes observed may reflex involvement of small airways.

Administration, Intranasal↗

PubMed1975

[Screening tests for the determination of risk groups in respiratory insufficiency under conditions of epidemiological serial studies].

A report is given on a system of effective respiratory functional tests which proved its value when used in epidemiological mass examinations in connection with the mass miniature radiography in Berlin, Brandenburg and Halle as well as in mass examinations in Berlin enterprises. Thereby a new development - Pneumotest - is presented, an electronic spirometer for the recognition of ventilatory and distribution analytic preliminary parameters with digital indication of 5 sizes of the breath test manoeuvre which is to be applied as successor of the well-known spirotest device. In this paper the functional capacity of the further developed fluorographic densimetry as preliminary emphysematic test is proved. The application of the rapid helium or O2/N2 breathing back technique for the determination of residual volume and closing volume has in connection with the automatic establishment of the measuring values proved as basic diagnostics for emphysema with a large efficiency and at the same time with high reliability. The digestion of the epidemiological functional data with the help of electronic data processing is carried out in the own microcalculator system following immediately the application during examination.

Humans↗

PubMed1989

[Continuous positive airway pressure in the treatment of postoperative hypoxia].

The physiopathology of postoperative hypoxia has been analysed, the cause being identified in the worsening of the V/Q ratio consequent on the reduction in CFR. By increasing CFR, CPAP reduces the superimposition of Tidal Volume and Closing Volume, thus reducing dysventilated zones and thereby improving the V/Q ratio and oxyaemia. With these premises, 18 patients undergoing cholecystectomy were examined; 8 of them were treated in the postoperative period with CPAP at pre-established intervals. The results confirm its effectiveness in terms of PaO2 improvement and the need for constant administration, considering that the benefits are lost when the patient is disconnected from the mask.

Blood Gas Monitoring, Transcutaneous↗

PubMed1976

[Computer measurement of residual volume and alveolar gas distribution parameters in epidemiological studies (author's transl)].

Starting from the quick helium-rebreathing-technique of Kowalski-Visser a method of combined measurement of residual volume and closing volume in one test was developed using automatic data - collection in 3 different variants, that is- automatic control during test- manual control during test and- manual control on the table. A computer program running on minicomputer Cellatron 8205 is described. Experiences using the different program-variants are discussed.

Diagnosis, Computer-Assisted↗