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Results for “VITAL CAPACITY”

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PubMed2003

Accelerometry of adductor pollicis muscle predicts recovery of respiratory function from neuromuscular blockade.

BACKGROUND: Residual paralysis increases the risk of pulmonary complications but is difficult to detect. To test the hypothesis that accelerometry predicts effects of residual paralysis on pulmonary and upper airway function, the authors related tests of pulmonary and pharyngeal function to accelerometry of adductor pollicis muscle in 12 partially paralyzed volunteers. METHODS: Rocuronium (0.01 mg/kg + 2-10 microg x kg-1 x min-1) was administered to maintain train-of-four (TOF) ratios (assessed every 15 s) of approximately 0.5 and 0.8 over a period of more than 5 min. The authors evaluated pharyngeal and facial muscle functions during steady state relaxation and performed spirometric measurements every 5 min until recovery. Upper airway obstruction was defined as a mean ratio of expiratory and inspiratory flow at 50% of vital capacity of greater than 1. The TOF ratio associated with "acceptable" pulmonary recovery (forced vital capacity and forced inspiratory volume in 1 s of > or =90% of baseline) was calculated using a linear regression model. RESULTS: At peak blockade (TOF ratio 0.5 +/- 0.16), forced inspiratory flow was impaired (53 +/- 19%) to a greater degree than forced expiratory flow (75 +/- 20%) with a mean ratio of expiratory and inspiratory flow at 50% of vital capacity of 1.18 +/- 0.6. Upper airway obstruction, observed in 8 of 12 volunteers, paralleled an impaired ability to swallow reported by 10 of 12 volunteers. In contrast, all volunteers except one could sustain a head lift for more than 5 s. The authors calculated that a mean TOF ratio of 0.56 (95% confidence interval, 0.22-0.71) predicts "acceptable" recovery of forced vital capacity, whereas forced inspiratory volume in 1 s was impaired until a TOF ratio of 0.95 (0.82-1.18) was reached. A 100% recovery of TOF ratio predicts an acceptable recovery of forced vital capacity, forced inspiratory volume in 1 s, and mean ratio of expiratory and inspiratory flow at 50% of vital capacity in 93%, 73%, and 88% of measurements (calculated negative predictive values), respectively. CONCLUSION: Impaired inspiratory flow and upper airway obstruction frequently occur during minimal neuromuscular blockade (TOF ratio 0.8), and extubation may put the patient at risk. Although a TOF ratio of unity predicts a high probability of adequate recovery from neuromuscular blockade, respiratory function can still be impaired.

Adult↗

PubMed1976

Idiopathic scoliosis. Gas exchange and the age dependence of arterial blood gases.

The aims were to examine the gas exchange and arterial blood gas abnormalities among patients with scoliosis, and the correlation of these abnormalities with age and severity of deformity. Means among 51 patients were as follows: age 25.4 +/- 17.5 yr, angle of scoliosis 80.2 +/- 29.9 (SD), vital capacity 1.94 +/- 0.91 (SD) (i.e. 60.6 +/- 19.2% of predicted), PaO2 85.8 +/- 12.0 (SD), PaCO2 42.4 +/- 8.0, physiological dead space to tidal volume ratio 0.438 +/- 0.074 (SD), and alveolar-arterial oxygen difference breathing air 14.9 +/- 8.9 (SD). Statistically significant correlations were as follows: the PaCO2 and physiological dead space to tidal volume ratio increased with age, and the PaO2 and alveolar ventilation decreased with age. The PaO2, alveolar ventilation, and tidal volume were inversely related to the angle of scoliosis and directly related to the vital capacity, precent predicted vital capacity, and the compliance of the respiratory system. The physiological dead space to tidal volume ratio and the alveolar-arterial oxygen difference were inversely related to the vital capacity, percent predicted vital capacity, and the compliance of the respiratory system. PaCO2 was directly related to the elastance of the respiratory system. We conclude that ventilation-blood flow maldistribution as a result of deformity of the rib cage was the primary abnormality in gas exchange, and that with age there was progressive deterioration in gas exchange. The age-dependent increase in PaCO2 and decrease in alveolar ventilation were due to the increasing physiological dead space to tidal volume ratio and failure of a compensatory increase in ventilation.

Adolescent↗

PubMed1993

Respiratory changes due to extreme cold in the Arctic environment.

Effects of acute exposure and acclimatisation to cold stress on respiratory functions were investigated in healthy tropical Indian men (n = 10). Initial baseline recordings were carried out at Delhi and thereafter serially thrice at the arctic region and once on return to Delhi. For comparison the respiratory functions were also evaluated on Russian migrants (RM; n = 7) and Russian natives (RN; n = 6). The respiratory functions were evaluated using standard methodology on a Vitalograph: In Indians, there was an initial decrease in lung vital capacity (VC), forced vital capacity (FVC), forced expiratory volume 1st s (FEV1), peak expiratory flow rate (PEFR) and maximum voluntary ventilation (MVV) on acute exposure to cold stress, followed by gradual recovery during acclimatisation for 4 weeks and a further significant improvement after 9 weeks of stay at the arctic region. On return to India all the parameters reached near baseline values except for MVV which remained slightly elevated. RM and RN showed similar respiratory functions at the beginning of acute cold exposure at the arctic zone. RN showed an improvement after 10 weeks of stay whereas RM did not show much change. The respiratory responses during acute cold exposure are similar to those of initial altitude responses.

Acclimatization↗

PubMed2003

Pulmonary function abnormalities associated with exposure to automobile exhaust in a diesel bus garage and roads.

In Kolkata city the road transports are maintained by private and Government organization. A major work force belonged to the State Transport Corporation (KSTC), Government of West-Bengal. The pollution caused by these vehicles affects the workers health and caused different types of respiratory problems. This study was undertaken to assess the pulmonary function status of these workers. City KSTC garage workers were investigated and categorically divided into two group: garage mechanics and the (2) those transporting the passengers (drivers and conductors). Vital capacity (VC), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) were recorded by Spirovit-SP-10 (Schiller Ltd, Switzerland) and Wright's Peak Flow Meter (UK) on 236 workers. The different flow volumes, FEV(1), FEV(1%), and flow rates, FEF(02-121), FEF(25-75%), etc. were calculated. The administrative people had higher PFT than the other categories. Drivers and conductors have almost equal mean PFT values but mechanical workers had slightly higher. PFT values according to different age ranges and duration of exposure showed gradual decrement as age and duration of exposure increased. Non-smokers had higher lung volumes compared to smokers and ex-smokers. Restrictive, obstructive and combined types of impairments were noticed in 28.4%, 1.7% and 2.9%, respectively, workers. The restrictive impairment was found to be 30.4% in conductors; 28.9% in drivers, 27.9% in mechanics and 21.7% in administration people. Obstructive type of impairment was found to be 2.9% in both drivers and conductors. The effect of pollution by dust and fumes may be responsible for these pulmonary function impairments, restrictive impairments being greater.

Forced Expiratory Volume↗

PubMed2006

An epidemiological study of talc-related respiratory morbidity among employees of a rubber industry in Shiraz-Iran.

OBJECTIVES: The main purpose of this study was to assess and characterize the pulmonary reactions associated with occupational exposure to talc dust. METHODS: Ninety-seven talc workers and 110 unexposed employees as the reference group were randomly selected from a local rubber industry. Standardized respiratory questionnaires were administered to the subjects, they underwent chest X-ray and were examined by a specialist for any possible respiratory abnormality to be diagnosed. Furthermore, pulmonary function tests (PFTs) were measured just before and after the work shift. Moreover, to assess the extent to which workers had been exposed to talc dust, using standard methods, inhalable and respirable dust concentrations were measured in different dusty worksites. RESULTS: The average (mean +/- SD) age (years), weight (kg), height (cm) and duration of exposure to talc dust (years) for the exposed group were 35.8 +/- 6.75, 73.1 +/- 9.2, 172.3 +/- 5.9 and 11.79 +/- 5.3, respectively. The corresponding values for the non-exposed group were 36.1 +/- 6.87, 73.36 +/- 8.1, 173.2 +/- 5.7 and 0 +/- 0, respectively. Atmospheric concentrations of inhalable and respirable talc dust were estimated to be 41.8 +/- 23.52 and 19.8 +/- 8.04 mg/m(3) (mean +/- SD), respectively. Talc exposed subjects had a significantly higher prevalence of respiratory symptoms. Similarly, PFTs revealed that exposure to this lubricating agent was associated with significant decreases in the mean percentage predicted of vital capacity (VC), forced vital capacity (FVC) and forced expiratory volume in the first second (FEV(1)). Likewise, there was a general tendency for VC, FVC and FEV(1) to decrease as estimated cumulative exposure (years worked) increased. Moreover, there was an acute reduction in some parameters of pulmonary function such as VC, FVC and FEV(1), over the work shift. Chest radiographs of exposed workers showed that pneumoconiosis profusions were between p 0/0 and p 2/1 according to the ILO 1980 chest X-ray classification. CONCLUSIONS: These results that are in full agreement with our preliminary observations, support the notion that occupational inhalation exposure to talc is associated with both acute and chronic respiratory disorders and induces bronchitis and interstitial lung disease.

Adult↗

PubMed2006

Pulmonary function in multiple sclerosis without any respiratory complaints.

OBJECTIVES: Pulmonary complications in severe multiple sclerosis (MS) are often seen secondary to respiratory muscle dysfunction. The development of respiratory muscle dysfunction and its association with disability during the course of MS is unknown. In our study, we investigated the predictive value of respiratory muscle functions and the change in forced vital capacity (Delta forced vital capacity [FVC]; FVC upright-FVC supine) to detect deterioration of respiratory muscle functions in the early phase of MS. PATIENTS AND METHODS: Twenty-one MS patients with a median age of 34.5+/-9.45 years were enrolled. Fourteen cases were relapsing-remitting, six were secondary progressive, one was primary progressive type. The mean duration of disease was 10.76+/-6.6 years. Seventeen healthy subjects with a median age of 40.7+/-7.6 years were chosen as a control group. Smoking habit was similar in both groups. Pulmonary function tests (PFT), lung volumes, diffusion, respiratory muscle function ( P(Imax) , P(Emax)), mouth occlusion pressure, and indirect sign of respiratory center function (P(0.1)) tests were performed. PFT were repeated in supine and upright positions. RESULTS: Our results in the MS group and the control group, respectively, were: diffusion (DL(CO): 18.8+/-4.2 vs. 26.4+/-7.3 mL/mmHg/min), P(I(max) (82.1+/-26.3 vs. 109.1+/-23.3 cm H(2)O), P(E(max) (119.2+/-42 vs. 171.8+/-50.2 cm H(2)O), P(0.1) (2.6+/-0.7 vs. 4.2+/-0.7). All parameters were lower in the MS group compared with the control group (p<0.05). In the MS group, FVC values in the upright position were higher than FVC values in the supine position. The difference in FVC values in MS patients between the upright and supine positions (Delta FVC) was also found to be significantly higher than in the control group (Delta FVC 262.3+/-247.6 (MS), 98.8+/-179.1 mL (CONTROL)) (p<0.01). CONCLUSION: Our results indicate the presence of pulmonary dysfunction in MS even in the absence of any respiratory symptoms.

Adult↗

PubMed2006

Bronchodilation and bronchoconstriction: predictors of future lung function in childhood asthma.

BACKGROUND: Persistently low levels of lung function are associated with subsequent symptoms in patients with asthma as children. OBJECTIVES: We hypothesized that objective measures of baseline pulmonary function would be independently associated with future lung function in the Childhood Asthma Management Program and that these associations might vary with treatment. METHODS: We evaluated the association of FEV1, airway responsiveness, and bronchodilator response at randomization as predictors of longitudinal growth in FEV1 at the 48-month follow-up visit in the 1041 Childhood Asthma Management Program participants. RESULTS: Baseline levels of airway responsiveness and bronchodilator response were significantly associated with baseline level of lung function. In multivariate models, higher bronchodilator response (beta = 0.22; P < .0001), log PC20 (beta = 1.82; P < .0001), and FEV1 (beta = 0.58; P < .0001) at randomization were each associated with higher levels of prebronchodilator FEV1, as a percent of predicted, after 4 years. Similar associations were noted for prebronchodilator forced vital capacity and FEV1/forced vital capacity ratio. Baseline bronchodilator response was a particularly powerful predictor of lung function improvements while on inhaled corticosteroids, whereas airway responsiveness was a better predictor in subjects not randomized to any controller medications. CONCLUSION: We conclude that baseline bronchodilator response, airway responsiveness, and level of FEV1 are independent predictors of subsequent level of FEV1 in childhood asthma and may have treatment-specific prognostic significance for persistence of symptoms into early adulthood. CLINICAL IMPLICATIONS: In asthma, bronchodilator and bronchoconstrictor responses are independent predictors of future lung function and should not be used interchangeably; bronchodilator response may indicate good response to inhaled corticosteroids.

Asthma↗

PubMed2004

Early results of endoscopic lung volume reduction for emphysema.

BACKGROUND: We determined the feasibility, safety, and short-term efficacy of bronchoscopic placement of a one-way endobronchial valve in selected bronchopulmonary segments as an alternative to surgical lung volume reduction. METHODS: A total of 21 patients with incapacitating emphysema who underwent this procedure were studied. All patients had placement of the endobronchial valves into the most emphysematous lung segments. We recorded any major complications or deaths attributed to the procedure and analyzed (1) improvements in the spirometric and functional parameters and quality of life and (2) the radiologic changes compared with the baseline data at 30 and 90 days. RESULTS: A total of 20 patients had complete follow-up data. There was no mortality in the group studied. The forced expiratory volume at 1 second, forced expiratory volume at 1 second (percentage of predicted), forced vital capacity, and forced vital capacity (percentage of predicted) all improved significantly at 90 days (0.73 +/- 0.26 L vs 0.92 +/- 0.34 L [P =.009]; 33.3% +/- 11.9% vs 42.2% +/- 15.0% [P =.006]; 1.94 +/- 0.62 L vs 2.25 +/- 0.61 L [P =.015]; and 63.3% +/- 17.6% vs 73.9% +/- 17.1% [P =.012], respectively). The 6-minute walking distance improved at 30 and 90 days (251.6 +/- 100.2 m vs 306.3 +/- 112.3 m and 322.3 +/- 129.7 m; P =.012 and P =.003). The results of the 36-Item Short-Form Health Survey and the St George Respiratory Questionnaire showed significant improvements at 90 days. The Medical Research Council dyspnea grade also improved significantly at 30 and at 90 days (P =.006 and P =.003, respectively). CONCLUSIONS: Endobronchial valve placement is a safe procedure, with significant short-term improvements in functional status, quality of life, and relief of dyspnea in selected patients with emphysema. A larger study with long-term follow-up is therefore warranted.

Adult↗

PubMed1983

Depression of respiratory function by pneumatic antishock trousers in traumatic quadriplegia.

A case of mild hypoventilation associated with an incompletely inflated pneumatic antishock suit in traumatic quadriplegia is presented. Pulmonary function studies were performed on the same patient 23 days later. Base line studies were performed and then repeated with the antishock suit inflated to 40 and then 100 mm Hg. Measurements were made of tidal volume (Vt), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), forced vital capacity (FVC), forced vital capacity in one second (FEV1), and maximum voluntary ventilation (MVV). With increasing suit pressures, all parameters decreased with the exception of the ERV, which was initially zero. Traumatic quadriplegia must be added to the list of disorders in which caution must be used when considering the use of the abdominal compartment of the pneumatic antishock suit.

Accidents, Traffic↗

PubMed1983

Nonorganic upper airway obstruction.

Two cases of severe dyspnea and stridor with upper airway obstruction of obscure origin are discussed. Complete medical evaluation could identify no organic cause for the symptoms, and functional upper airway obstruction was diagnosed. Treatment with psychotherapy and relaxation techniques was successful. Diagnosis can be made with pulmonary function studies. Flow-volume loops may show a lower inspiratory vital capacity than expiratory vital capacity and a discrepancy between inspiratory flow limitation and airway resistance. It is important to establish a functional etiology to prevent unnecessary treatment and provide proper care.

Adolescent↗

PubMed2004

Respiratory movements are altered three months and one year following cardiac surgery.

OBJECTIVE: Pulmonary complications following cardiac surgery through sternotomy are well known, but little is known about the proposed alterations of the chest wall mechanism. The purpose of this study was to examine changes in chest wall motion and pulmonary function after cardiac surgery. DESIGN: The subjects were 20 cardiac surgery patients, 13 men and 7 women, mean age 65 years. MEASUREMENTS: Bilateral respiratory movements were measured using the Respiratory Movement Measuring Instrument before, 3 and 12 months after the operation. Vital capacity (VC), forced vital capacity (FVC) and forced expiratory volume (FEV1) were measured with the Pulminet III (Gold Godart Ltd Vitalograph Alpha Ltd. Maids Morton, Buckingham, England) preoperatively, 3 and 12 months postoperatively, and radiographs were taken at the same points in time. ANALYSIS: Descriptive statistics, paired sample t-tests, Mann-Whitney and Wilcoxon Signed Rank tests were used for analyses, p < or = 0.05. RESULTS: Average abdominal movements 3 months postoperatively were significantly decreased and the difference between right and left side in upper thoracic and abdominal movements was significant. All pulmonary function measurements except the FEV1/FVC showed a significant decrease and a restrictive pattern compared with preoperative values. Twelve months after the operation the upper thoracic movements were significantly increased. Five patients had an abnormal chest x-ray before the operation, eight 3 months and three 12 months after the operation. CONCLUSION: The motor system of the respiratory organs suffers considerable injury from cardiac surgery, which in part at least can explain the restrictive breathing 3 months postoperatively.

Abdominal Wall↗

PubMed2004

Effect of obesity and thoracic epidural analgesia on perioperative spirometry.

BACKGROUND: Lung volumes in obese patients are reduced significantly in the postoperative period. As the effect of different analgesic regimes on perioperative spirometric tests in obese patients has not yet been studied, we investigated the effect of thoracic epidural analgesia and conventional opioid-based analgesia on perioperative lung volumes measured by spirometry. METHODS: Eighty-four patients having midline laparotomy for gynaecological procedures successfully completed the study. Premedication, anaesthesia and analgesia were standardized. The patients were given a free choice between epidural analgesia (EDA) (n=42) or opioids (n=42) for postoperative analgesia. We performed spirometry to measure vital capacity (VC), forced vital capacity, peak expiratory flow, mid-expiratory flow and forced expiratory volume in 1 s at preoperative assessment, 30-60 min after premedication and 20 min, 1 h, 3 h and 6 h after extubation. RESULTS: Baseline values were all within the normal range. All perioperative spirometric values decreased significantly with increasing body mass index (BMI). The greatest reduction in VC occurred directly after extubation, but was less in the EDA group than in the opioid group: mean of -23(sd 8)% versus -30(12)% (P<0.001). In obese patients (BMI>30) the difference in VC was significantly more pronounced than in patients of normal weight (BMI<25): -45(10)% versus -33(4)% (P<0.001). Recovery of spirometric values was significantly quicker in patients receiving EDA, particularly in obese patients. CONCLUSION: We conclude that EDA should be considered in obese patients undergoing midline laparotomy to improve postoperative spirometry.

Adult↗

PubMedDate not supplied

Breathing out into water during subtotal immersion: a therapy for chronic pulmonary emphysema.

OBJECTIVE: To determine the importance of a breathing out into water exercise during subtotal immersion for emphysematous patients. DESIGN: Results of a respiratory function test and arterial blood gas analysis were examined to compare the programs of breathing exercise with and without the breathing out into water exercise. The breathing exercises in a pool filled with 38 degrees C water were performed 30 min/day, 5 days/wk, for 2 mo in 17 patients with stable chronic emphysema. Patients were randomly assigned to breathing exercise programs including subtotal water immersion with the nose and mouth either immersed (9 patients) or out of the water (8 patients) during exhalation. RESULTS: The ratio of %forced expired volume in 1 sec to forced vital capacity and %forced vital capacity at rest were significantly increased in the program with the breathing out into water exercise, but they did not change in the program without the breathing out into water exercise. A significant increase in peak flow was observed in the former program, although it did not change in the latter program. The maximal expiratory flow at 25% did not change in either program. Pao2 was significantly increased and Paco2 was significantly decreased in the former program, although a trend for a decrease in Paco2 was observed in the latter program. CONCLUSIONS: These results suggest that the breathing out into water exercise enhances the effects of a breathing exercise during immersion and is useful in rehabilitation for chronic pulmonary emphysema.

Aged↗

PubMed2005

Comparison of perioperative spirometric data following spinal or general anaesthesia in normal-weight and overweight gynaecological patients.

BACKGROUND: There is limited data comparing the impact of spinal anaesthesia (SA) and general anaesthesia (GA) on perioperative lung function. Here we assessed the differences of these two anaesthetic techniques on perioperative lung volumes in normal-weight (BMI < 25) and overweight (BMI 25-30) patients using spirometry. METHODS: We prospectively studied 84 consenting patients having operations in the vaginal region receiving either GA (n = 41) or SA (n = 43). Both groups (GA and SA) were further divided into two subgroups each (normal-weight vs. overweight). We measured vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), midexpiratory (MEF25-75) and peak expiratory flow rates (PEFR) at the preoperative assessment (baseline), after premedication, after effective SA, and 20 min, 1 h, 2 h and 3 h after the operation (last measurement after patient mobilization). RESULTS: Premedication was associated with a small but significant decrease in lung volumes in direct correlation with BMI (-5%). Spinal anaesthesia resulted in a significant reduction in lung volumes in overweight as opposed to normal-weight patients. Postoperatively, lung volumes were significantly more reduced following GA than SA as indicated by differences in mean VC (SD) of -12 (6)% vs. -6 (5)% 20 min after the end of the operation in the normal-weight and -18 (5)% vs. -10 (5)% in the overweight patients. There was a significant impact of BMI on postoperative respiratory function, which was significantly more important in the GA group than in the SA group, and recovery of lung volumes was more rapid in the normal-weight patients than in the overweight patients, particularly in the SA group. CONCLUSION: In gynaecological patients undergoing vaginal surgery, the impact of anaesthesia on postoperative lung function as assessed by spirometry was significantly less after SA than GA, particularly in overweight patients.

Adult↗

PubMed1983

Respiratory function after paralysis of the right hemidiaphragm.

We studied a 45-yr-old man with normal lung function before and 7 wk after right phrenic nerve crush. Total lung capacity, functional residual capacity, and forced vital capacity decreased with residual volume remaining unchanged. Static compliance was also unchanged. Ventilatory response to CO2 (delta Ve/delta PaCO2) was preserved, but P0.1 response to CO2 (delta P0.1/delta PaCO2) increased. Analysis of raw mouth pressure suggested that these responses were the result of a new rapid pattern of inspiratory pressure development. Regional washout was slowed on the side with paralysis, but the normal apex-to-base gradient of regional volumes was preserved. Inhaled 133Xe boluses were distributed away from the side of paralysis, and bolus distribution changed relatively little with increased flow. These results suggested that in compensation for paralysis of a hemidiaphragm, a new pattern of inspiratory muscle recruitment developed, involving more rapid contraction of the remaining muscles of inspiration.

Forced Expiratory Volume↗

PubMed1984

Postoperative pulmonary function in children. Comparison of scoliosis with peripheral surgery.

We measured lung volumes, forced expirograms, and arterial blood gases in 2 groups of elective pediatric surgical patients (mean age, 11.4 +/- SD 2.8; n = 11, 12 operations) the day prior to surgery (control) and between the first and eighth postoperative days. The patients were Group I: peripheral surgery (n = 6) and Group II: reconstructive surgery for scoliosis (n = 5). The preoperative lung volumes and forced expiratory volume in one second were within the predicted normal range in both groups, except for a reduction in total lung capacity (TLC) and vital capacity (VC) in Group II. The postoperative lung volumes in Group I were not significantly different from the preoperative volumes. In group II, on postoperative Days 2 and 3, the lung volumes as a percent of preoperative volumes (mean +/- SEM) were VC, 44 +/- 11; functional residual capacity (FRC), 81 +/- 6; residual volume, 124 +/- 10; TLC, 61 +/- 10. Although the mean FRC returned to the preoperative volume by postoperative Days 5 and 6, the VC and its components remained reduced on postoperative Days 5, 6, and 8. We conclude that postoperative lung volume abnormalities are related to the site and magnitude of surgery and associated phenomena, such as pain, and preoperative respiratory function abnormalities.

Adolescent↗

PubMed1985

Small airways disease and mineral dust exposure. Prevalence, structure, and function.

Previously we described a lesion of the small airways that appears related to mineral dust exposure and is found in asbestos and nonasbestos dust-exposed populations. To determine the usefulness of this lesion as a marker for mineral dust exposure, and to determine whether it produces functional consequences, we examined a group of 53 workers who had been either hard rock miners or in the asbestos, construction, and shipyard industries. The specific lesion (mineral dust airways disease (MDAD] consists of marked fibrosis and pigmentation of the respiratory bronchioles and was found in 13 of 53 workers with dust exposure, but only in 1 of 121 without dust exposure. Compared with age and smoking-matched dust-exposed control subjects, patients with this lesion had significant abnormalities of forced expiratory volume in one second (FEV1), forced expiratory flow during the middle half of the forced vital capacity (FEF25-75), vital capacity (VC), and nitrogen washout. In addition to fibrosis in the walls of respiratory bronchioles, these patients also had significant increases of fibrosis in the walls of membranous bronchioles, indicating that changes in the small airways are widespread in this subset of workers. We conclude that markedly abnormal small airways are present in some workers with mineral dust exposure; pathologic observation of this lesion is a good indicator of dust exposure, and its presence is associated with abnormalities of air flow greater than those induced by smoking alone. The presence of this lesion in only a portion of dust-exposed workers may account for contradictory results in past studies that attempted to demonstrate air flow abnormalities associated with mineral dust exposure.

Aged↗

PubMed1996

Acute exacerbations in patients with COPD: predictors of need for mechanical ventilation.

Predictive factors in mechanically-ventilated patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) have been extensively studied but not in spontaneously breathing patients. The aim of this retrospective study was to evaluate the contribution of parameters of respiratory mechanics, clinical and nutritional status in predicting the need for mechanical ventilation (MV) in COPD patients treated with medical therapy for an acute exacerbation. Anthropometric data, Acute Physiology and Chronic Health Evaluation (APACHE) II score, bedside spirometry, breathing pattern, respiratory mechanics and blood gases were measured in 39 COPD patients upon hospital admission for exacerbation of their disease. Fourteen patients in whom MV was necessary were compared with 25 patients in whom medical therapy was enough for a good outcome. The discriminant analysis showed, with decreasing order of power, that nutritional prognostic index (NPI), APACHE II score, forced expiratory volume in one second/forced vital capacity (FEV1/FVC) ratio, vital capacity (VC) (% predicted) and FVC (% pred) provided a significant distinction between the two groups. The discriminant equation considering NPI, and FVC (% pred) could correctly predict the success in 76% of the patients. A multiparametric stepwise regression analysis showed that APACHE II score was significantly correlated with NPI, VC (% pred), pressure time index (PTI) and duty cycle, i.e. fraction of inspiration to duration of total breathing cycle (tl/ttot). In conclusion, underlying general conditions as assessed by malnutrition and APACHE II score were shown to be unfavourable indices of outcome for chronic obstructive pulmonary disease patients who experienced an exacerbation of their disease and were treated with medical therapy. Flow limitation data as assessed by the forced expiratory manoeuvre may provide additional information.

APACHE↗