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Pulmonary function abnormalities in children with sickle cell disease.

BACKGROUND: Adults with sickle cell disease (SCD) have restrictive lung function abnormalities which are thought to result from repeated lung damage caused by episodes of pulmonary vaso-occlusion; such episodes start in childhood. A study was therefore undertaken to determine whether children with SCD have restrictive lung function abnormalities and whether the severity of such abnormalities increases with age. METHODS: Sixty four children with SCD aged 5-16 years and 64 ethnic matched controls were recruited. Weight and sitting and standing height were measured, and lung function was assessed by measurement of lung volumes and forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF) before and after bronchodilator. RESULTS: Compared with the control subjects, the children with SCD had lower mean (SD) sitting height (69 (6.3) cm v 73 (7.7) cm; p=0.004), sitting:standing height ratio (0.50 (0.02) v 0.51 (0.01); p<0.0001), weight (33 (10.9) kg v 41 (14.9) kg; p=0.001), functional residual capacity measured by a helium gas dilution technique (1.2 (0.3) l v 1.3 (0.4) l; p=0.04), FEV1 (1.5 (0.5) l v 1.9 (0.7) l; p=0.0008), FVC (1.7 (0.6) l v 2.1 (0.8) l; p=0.001), and PEF (3.9 (1.3) l/s v 4.8 (1.5) l/s; p=0.0004). The effect of age on lung function differed significantly between the children with SCD and the controls for total lung capacity and vital capacity measured by plethysmography and functional residual capacity measured by helium gas dilution. CONCLUSION: Lung function differs significantly in children with SCD compared with ethnic matched controls of a similar age. Our results suggest that restrictive abnormalities may become more prominent with increasing age.

Adolescent↗

Airway obstruction and perioperative complications in smokers undergoing abdominal surgery.

BACKGROUND: The goal of this study was to determine whether airway obstruction determined by preoperative spirometry predicts perioperative complications in smokers undergoing abdominal surgery whose treatment is managed according to current clinical practice. METHODS: A pulmonary function database identified patients undergoing abdominal surgery who met the following criteria for airway obstruction (n = 135): a forced expiratory volume less than 40% of predicted normal value, a forced expiratory volume:forced vital capacity ratio less than the lower limit of predicted normal, a smoking history of more than 20 pack-years, and an age older than 35 yr. A group of patients without airway obstruction (n = 135) was matched for gender, surgical site (upper vs. lower abdominal), smoking history, and age. Medical records were reviewed by an abstractor to identify perioperative complications that occurred within 30 days after surgery. RESULTS: The forced expiratory volume values were 0.9+/-0.21 (mean +/- SD) and 2.9+/-0.61 in patients with and without airway obstruction, respectively. When analyzed by conditional logistic regression using the 1:1 matched-pairs feature, including age, pack-year smoking history, site of incision, and current smoking status as covariates, in patients with airway obstruction bronchospasm was more likely to develop (odds ratio, 6.9 [95% confidence interval, 1.2 to 38.4]) but the patients were not more likely to need prolonged endotracheal intubation (odds ratio, 1.1 [95% confidence interval, 0.4 to 3.2]). They were also no more likely to need prolonged intensive care admission or readmission. The frequency of other complications was less than 5%. CONCLUSION: When other factors were considered, preoperative airway obstruction predicted the occurrence of bronchospasm, but not prolonged endotracheal intubation, in smokers undergoing abdominal surgery who are treated according to current clinical practices.

Abdomen↗

The forced expiratory volume-time curve estimation using the electrocardiogram.

The feasibility of estimating the forced expiratory volume-time curve from the amplitude modulation of the electrocardiogram was studied using a numerical torso model and ECG signal processing. A two dimensional numerical model of the torso was solved for the maximum expiration and inspiration to study the changes in the surface potential as a result of changes in the lung volume. The numerical model showed that significant changes in the surface potential amplitude occur between maximum inspiration and maximum expiration and that this amplitude change in the left-right axis of the torso might be three times as large as in the front-back axis. In the experimental setup, ECG waveforms from the surface of the chest and the mouth air flow were simultaneously recorded from four male subjects during several forced vital capacity (FVC) maneuvers. The amplitude of the QRS complex was measured for different expired lung volumes and an estimation of the forced expiratory volume-time curve was obtained. The FVC and the FEV1 (forced expiratory volume after 1 s) spirometry indices were calculated for the two volume-time curves obtained from the electrocardiogram and from the spirometry measurements. The results differ between 0.1 and 0.8 1. These preliminary results are encouraging and might indicate that a relationship between the volume-time curve during FVC test and the electrocardiogram signals does exist. Further validation in a larger number of subjects and patients is needed before the technique can be applicable for clinical use.

Adult↗

An epidemiologic study of a group of talc workers.

Chest roentgenograms, pulmonary function assessment by spirometry, respiratory symptoms, smoking history, and occupational history by questionnaire were obtained from 121 male talc miners and millers exposed to talc containing tremolite and anthophyllite asbestiform fibers. Ninety-three of the employees had worked in talc only at the plant under study. Symptoms were only slightly more prevalent in talc workers when compared to potash miners. Mean pulmonary function (forced expiratory volume in one sec, forced vital capacity, and maximal expiratory flow at 50 and 75 per cent of vital capacity) of talc workers was significantly decreased in comparison to that of potash miners. The prevalence of pleural calcification and pneumoconiosis in talc workers with 15 or more years of employment was higher than in potash miners. The prevalence of pleural thickening was 31 per cent in those who worked more than 15 years and was significantly increased as compared to that in potash miners. Workers with pleural thickening had decreased pulmonary function in comparison to those who did not. Decreased one-sec forced expiratory volume and forced vital capacity were associated with exposure to respirable particulate and asbestiform fibers.

Adult↗

Pulmonary function studies in healthy non-smoking women of Calcutta.

Pulmonary function measurements were made in 230 healthy non-smoking women from Calcutta with an age range of 20-59 years. The tests consisted of vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory volume in one second as a percentage of forced vital capacity (FEV1%), forced expiratory time (FET), maximum voluntary ventilation, uncontrolled frequency (MVVF), forced expiratory flow (FEF200-1200ml), forced mid-expiratory flow (FEF25-75%), forced end-expiratory flow (FEF75-80%) and peak expiratory flow rate (PEFR). Except for PEFR, all the measurements were made with the help of two 9-litre closed-circuit-type expirographs using standard spirometric techniques. PEFR was recorded with the help of two Wright peak flow meters. Prediction formulae were derived on the basis of physical characteristics. Age and height were found to be the significant predictor variables for VC, FVC and FEV1, while only age was significant for FEV1%. The FVC and FEV1 values of the subjects, standardized for age and height, are much lower than those of Americans, Europeans and Jordanians. On comparison with data reported from other parts of India, it was revealed that the VC and FEV1 values of the current study, after adjustment for age and height, were much higher than those of Southern Indians but comparable with those of North-Western Indians.

Adult↗

Comparison of outcomes after single and bilateral lung transplantation for obstructive lung disease.

BACKGROUND AND METHODS: To determine the long-term functional outcome for single versus bilateral lung transplant for nonseptic obstructive lung disease, we compared the results from 39 single and nine bilateral lung transplant procedures. The nine bilateral lung transplants included three en bloc double lung and six bilateral sequential lung transplants. RESULTS: Early deaths within 30 days of transplantation occurred in two of nine (22%) bilateral and 4 of 39 (10%) single lung transplants (p = Not significant). Compared with pretransplant values, pulmonary function as assessed by the spirometric indexes of the percent predicted forced vital capacity, forced expiratory volume in one second, forced expiratory volume in one second/forced vital capacity, and forced expiratory flow at 25% and 75% of forced vital capacity improved significantly up to at least 12 months after transplantation for both single and bilateral lung transplant recipients. The degree of pulmonary function improvement was better in single as compared with bilateral lung recipients. By 6 months after transplantation, all but one single and all bilateral lung recipients were in New York Heart Association class I or II (p = Not significant). One-year survival was significantly better after single (77%) compared with after bilateral lung transplantation (35%) (p < 0.05). CONCLUSIONS: These results suggest that single lung transplantation is the procedure of choice for patients with nonseptic obstructive lung disease.

Adolescent↗

Ventilatory parameters in healthy nonsmoking adults of Adriatic islands (Yugoslavia).

Forced expiratory volumes and flows (forced vital capacity (FVC), forced expiratory volume in one second (FEV1) peak expiratory flow (PEF), maximal expiratory flow at 25% (MEF25%), 50% (MEF50%) and 75% (MEF75%) of the FVC) have been measured in 909 healthy nonsmoking men and women, ranging in age from 18-86 yrs, who live on Eastern Adriatic islands (Yugoslavia). This area is essentially free from air pollution. The results have been analysed in terms of age and height and regression equations for each sex were derived. The equations for FVC and FEV1 were reliable and those for forced expiratory flows were not. Comparisons were made with prediction equations derived for other populations, especially with those which are commonly used in daily medical practice.

Adolescent↗

Relationship between the single-breath N test and age, sex, and smoking habit in three North American cities.

This report describes a collaborative study conducted in Montreal, Canada, Portland, Ore., and Winnipeg, Canada, to establish the relationship between the single-breath N2 test and age, sex, and smoking and to determine the prevalence of functional abnormalities in these populations. In nonsmokers, age-related regressions for closing volume, closing capacity, and the slope of phase III obtained from the single-breath N2 test, plus the ratio of the I-s forced expiratory volume to the forced vital capacity had very similar slopes, suggesting that differences in geographic location, climate, air pollution, and occupation had no effect on lung function detectable by these tests. Among the 6 city/six groups there was no systematic difference in the prevalence of functional abnormalities between the cities, but closing capacity expressed as a percentage of total lung capacity was abnormal most often in men and the slope of the alveolar plateau was abnormal most often in women. The prevalence of respiratory symptoms within different smoking categories was similar in the 3 cities. Although the number of cigarettes smoked had a significant effect on every test except the ratio of the I-s forced expiratory volume to forced vital capacity in men, the effect of age was considerably greater than the effect of smoking, and the dose-response relationship was weak. We conclude that additional factors may interact with smoking to place a smoker at risk of developing chronic airflow limitation.

Adult↗

The actions of dopamine on the airways.

BACKGROUND: Dopamine exerts inhibitory and excitatory effects on different systems. In the lungs, dopamine modulates respiratory functions through carotid bodies and modulates pulmonary blood vessel tone, alveolar liquids, and bronchial exchange, and possibly participates in the regulation of airways diameter. It has been reported that dopamine has no acute effect on human airways in normal subjects or those with asthma background. However, inhaled or infused dopamine decreased histamine-induced bronchoconstriction in both normal and asthmatic subjects. We have examined the possible modulating effect of dopamine on bronchial diameter by administering inhaled dopamine and the DA2 dopaminergic blocker metoclopramide to subjects with various degrees of bronchial tone. METHODS: We examined 56 volunteers. Arterial blood pressure and heart rate were determined in every subject. By means of spirometry, we measured forced vital capacity, forced expiratory volume in the first second, maximal forced expiratory flow, and forced expiratory flow at 50% of vital capacity, before and after each treatment. By inhalation with a nebulizer, we administered dopamine (0.5 microg/kg/min) to 10 healthy subjects, 10 subjects with asthma without acute bronchospasm, and 16 subjects with acute asthma attack; intravenous metoclopramide (7 microg/kg/min) was administered to 10 healthy subjects and 10 subjects with asthma without acute bronchospasm. For ethical reasons, metoclopramide was not used in subjects with acute asthma attack. STATISTICS: non-parametric Wilcoxon tests for paired samples, ANOVA tests, and Bonferroni multiple comparison tests were performed. RESULTS: Inhaled dopamine increased forced expiratory volume in the first second, forced vital capacity, maximal forced expiratory flow, and forced expiratory flow at 50% of vital capacity in the acute asthma attack group, but there were no modifications in the healthy group or in the asthma without acute bronchospasm group. Metoclopramide did not induce changes in respiratory parameters in healthy individuals or in those with asthma without acute bronchospasm. CONCLUSIONS: Inhaled dopamine was able to induce bronchodilatation when the bronchial tone was already increased by acute asthma attack, but it did not modify the resting bronchial tone in normals or in asthmatics without acute bronchospasm. DA2 blockade with metoclopramide did not modify resting bronchial tone either. We suggest that dopamine exerts a modulatory effect on bronchial tone of human airways depending on the degree of existing basal tone.

Administration, Inhalation↗

Comparison of breathing patterns during exercise in patients with obstructive and restrictive ventilatory abnormalities.

Patients with obstructive and restrictive ventilatory abnormalities suffer from exercise intolerance and dyspnea. Breathing pattern components (volume, flow, and timing) during incremental exercise may provide further insight in the role played by dynamic hyperinflation in the genesis of dyspnea. This study analyzed the breathing patterns of patients with obstructive and restrictive ventilatory abnormalities during incremental exercise. It also explored breathing pattern components with dyspnea at maximum oxygen uptake (VO2 max). Twenty patients, thirteen obstructive patients (forced expiratory volume 38% +/- 13% predicted, forced expiratory volume in 1 s/forced vital capacity ratio 39 +/- 8%), and seven restrictive patients (forced vital capacity 55 +/- 16% predicted, forced expiratory volume in 1 s/forced vital capacity ratio 84% +/- 11%) performed symptom-limited incremental exercise tests on a cycle ergometer with breath-by-breath determination of ventilation and gas exchange parameters. Breathing patterns were analyzed at baseline, 20, 40, 60, 80, and 100 percent of VO2 max. Dyspnea was measured at end-exercise with a 100 mm visual analogue scale. The timing ratio of inspiratory to expiratory time (T(I)/T(E)) and the flow ratio of inspiratory flow to expiratory flow ratio (V(I)/V(E)) were different (p < 0.008) between obstructive and restrictive patients at all exercise intensity levels. The timing components of expiratory time (T(E)) and inspiratory time to total time (T(I)T(TOT)) were significantly different (p < 0.008) at baseline and maximum exercise. Dyspnea scores were not significantly different. For obstructive patients, correlations were noted between T(I)/T(E), V(I)/V(E), T(I)T(TOT) and dyspnea (p < 0.05). Breathing pattern-timing components, specifically T(I)/T(E), in patients with obstructive and restrictive ventilatory abnormalities during exercise provided further insight into the pathophysiology of the two conditions and the contribution of dynamic hyperinflation to dyspnea.

Aged↗

Quantitative computed tomography versus spirometry in predicting air leak duration after major lung resection for cancer.

BACKGROUND: Emphysema is a well-known risk factor for developing air leak or persistent air leak after pulmonary resection. Although quantitative computed tomography (CT) and spirometry are used to diagnose emphysema, it remains controversial whether these tests are predictive of the duration of postoperative air leak. METHODS: Sixty-two consecutive patients who were scheduled to undergo major lung resection for cancer were enrolled in this prospective study to define the best predictor of postoperative air leak duration. Preoperative factors analyzed included spirometric variables and area of emphysema (proportion of the low-attenuation area) that was quantified in a three-dimensional CT lung model. Chest tubes were removed the day after disappearance of the air leak, regardless of pleural drainage. Univariate and multivariate proportional hazards analyses were used to determine the influence of preoperative factors on chest tube time (air leak duration). RESULTS: By univariate analysis, site of resection (upper, lower), forced expiratory volume in 1 second, predicted postoperative forced expiratory volume in 1 second, and area of emphysema (< 1%, 1% to 10%, > 10%) were significant predictors of air leak duration. By multivariate analysis, site of resection and area of emphysema were the best independent determinants of air leak duration. The results were similar for patients with a smoking history (n = 40), but neither forced expiratory volume in 1 second nor predicted postoperative forced expiratory volume in 1 second were predictive of air leak duration. CONCLUSIONS: Quantitative CT is superior to spirometry in predicting air leak duration after major lung resection for cancer. Quantitative CT may aid in the identification of patients, particularly among those with a smoking history, requiring additional preventive procedures against air leak.

Aged↗

Pulmonary function in military divers: smoking habits and physical fitness training influence.

Pulmonary function (PF) tests are procedures that measure the function of the lungs, revealing problems in breathing, and therefore are highly important in diving. In this article, we studied the PF in military divers and defined the differences between (A) males (n = 32) and females (n = 27), (B) male smokers and nonsmokers, and (C) female smokers and non-smokers. PF was established by measuring: the large airway variables: inspiratory-vital capacity, forced-vital capacity, 1-second forced-expiratory volume, and 1-second forced-expiratory volume:forced-vital capacity ratio; and small airway variables: peak-expiratory flow, maximal-mid-expiratory flow, and maximal-expiratory flow after 50% and 75% of exhalation, all in absolute and relative (predicted for age and stature) values. The t test showed a significant (p < or = 0.05) difference between smokers and nonsmokers, but only in the relative inspiratory-vital capacity. A multivariate analysis of the variance revealed significant differences between smokers and nonsmokers in large airway variables for males and females. The possible explanations regarding the metrics, the variable relationships, and the influence of physical fitness training are discussed.

Adult↗

Respiratory effects of spinal anaesthesia for caesarean section.

We report the changes observed in a number of pulmonary function tests performed on 36 patients undergoing Caesarean section under spinal anaesthesia. The tests comprised peak expiratory flow, forced expiratory volume in one second, forced vital capacity, forced expiratory volume in one second to forced vital capacity ratio and the maximal mid-expiratory flow. Significant changes occurred that are consistent with a restrictive ventilatory defect. These changes persisted for four hours after the induction of spinal anaesthesia. Administration of 35% oxygen by facemask failed to change significantly fetal umbilical vein pH or partial pressure of oxygen.

Adult↗

Double-blind evaluation of methylprednisolone versus placebo for acute asthma episodes.

Twenty-eight children with persistent bronchospasm after outpatient therapy were treated for eight days with methylprednisolone or placebo in a prerandomized double-blind manner, in addition to treatment with optimal oral bronchodilators. At follow-up visits 1, 7, and 14 days after onset of therapy, a history was taken and physical examination and pulmonary function tests were performed. Initially and on the 14th day, patients underwent cosyntropin tests of adrenal function. Patients kept daily peak flow charts. Both groups improved with time. However, by 24 hours after starting methylprednisolone therapy, the placebo group continued to show reversibility after isoproterenol inhalation whereas the methylprednisolone group did not. By day 7 there were significantly more patients with normal 1-second forced expiratory volume (FEV1) and forced expiratory flow in the middle half of the forced vital capacity (FEF25-75%) in the methylprednisolone group and mean FEF25-75% was significantly higher for this group (P less than .02). By day 14, six days after finishing treatment with the study drugs, more patients in the placebo group had residual wheezing, but pulmonary function tests were now similar for the two groups. Although both groups showed a decline in cosyntropin responsiveness on day 14 compared with day 1, there was no difference between the steroid- and placebo-treated patients. This study proves that short-term corticosteroid therapy will accelerate resolution of moderately severe and severe-acute attacks of asthma without significant suppression of adrenal function.

Adrenal Glands↗

Transit time analysis of the forced expiratory vital capacity in cystic fibrosis.

Transit time analysis of the forced expiratory vital capacity maneuver was applied to 37 patients with cystic fibrosis 8 to 22 years of age. This analysis divides the vital capacity into segments of air and assigns a transit time to each segment. The characteristics of the distribution of these transit times are used as measurements of pulmonary function. The quantities were compared with the forced vital capacity, 1-sec forced expiratory volume, ratio of 1-sec forced expiratory volume to vital capacity, peak flow, forced expiratory flow during the middle half of the forced vital capacity, maximal expiratory flow at 25 per cent of the vital capacity, specific airway conductance, and arterial PO2 of these patients. The standard deviation of the transit times was the most frequently abnormal. The mean transit time had the largest range of values in terms of its own standard deviation, and it was the best single estimate of over-all lung function because it correlated almost equally with large and small airway function. The coefficient of cariance of transit times was specific in detecting abnormality of small airways and was as sensitive in the detection of minimal lung disease as the standard deviation of transit times.

Adolescent↗

Lung function status of workers exposed to wood dust in timber markets in Calabar, Nigeria.

The effect of chronic exposure to dust from local woods such as ebony, achi, and iroko on lung function of timber market workers in Calabar - Nigeria, was studied. Forced vital capacity (FVC), Forced Expiratory Volume in one second, (FEV1), Forced Expiratory Volume as a percentage of forced vital capacity (FEV1 %), and Peak Expiratory Flow Rate (PEFR) were measured in 221 workers (aged 20-25 years) exposed to wood dust to assess their lung function and compared with 200 age- and sex- matched control subjects who were not exposed to any known air pollutant. The concentration of respirable dust was significantly higher in the test (P<0.001) than in control site. The mean values of FVC, FEV1, FEV1% and PEFR of the timber workers were significantly lower (P<0.01) than in control subjects. Respiratory symptoms such as cough, chest pain and nasal irritation had higher prevalence in the test group than in the control group. Non-respiratory symptoms (skin and eye irritation) were prevalent in the test group but not found in the control group. Workers exposed to wood dust had restrictive pattern of ventilatory function impairment. The lung function indices of the timber workers decreased with their length of service. Chronic exposure to wood dust impairs lung function.

Adult↗

Pulmonary function in patients with diabetes mellitus.

BACKGROUND: Pulmonary complications of diabetes mellitus have been poorly characterized. Although some authors have reported normal pulmonary function, others found abnormalities in lung volumes, pulmonary mechanics, and diffusing capacity. SUBJECTS AND METHODS: We studied pulmonary function in a group of patients with diabetes using a combined cardiopulmonary exercise test. Twenty-seven patients with diabetes aged 48 +/- 13 years participated in the study. RESULTS: Overall, forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow, midexpiratory phase, were within the predicted values, but the residual volume/total lung capacity ratio was slightly elevated. Comparison by diabetes type showed nonsignificant differences in forced expiratory volume in 1 second and forced expiratory flow, midexpiratory phase. Residual volume/total lung capacity ratio was significantly elevated in type 1 patients compared with type 2. Carbon monoxide diffusion capacity (DLCO) was normal in both groups. There was no correlation between the results on pulmonary function test and duration of disease, presence of microangiopathy, or glycemic control. The DLCO was significantly lower in patients with microangiopathic changes, but not when DLCO was corrected for alveolar volume. On the cardiopulmonary exercise test, maximal workload, maximum oxygen uptake, and maximal heart rate were less than predicted, whereas anaerobic threshold and ventilatory reserve were normal. No significant differences were noted in diabetes type, and there was no correlation between parameters of cardiopulmonary exercise test and the other variables. CONCLUSION: Spirometric values are preserved in patients with diabetes mellitus, and there are no defects in diffusing capacity. Cardiovascular factors may account for impaired physical performance. There is no need for routine screening of pulmonary function among diabetic patients.

Adult↗

Spirometry in healthy elderly Chinese.

Forced expiratory volume (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF) were measured in healthy subjects (129 men, 210 women) aged 60 years and above who were leading an independent and active life in the community. Women but not men showed an age related decline in FEV1 and FVC. Correlations of FEV1 and FVC with height were weaker than those reported for all age groups. Male ex-smokers had lower FEV1 values than current smokers and non-smokers. Regression equations are derived for men and women for predicting values appropriate to Chinese elderly people. These values are slightly lower than those for white people, but the difference is not as great as in values derived from surveys of all age groups.

Aged↗