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PubMed2005

The 1-year impact of severe acute respiratory syndrome on pulmonary function, exercise capacity, and quality of life in a cohort of survivors.

OBJECTIVE: To examine pulmonary function, exercise capacity, and health-related quality of life (HRQoL) among severe acute respiratory syndrome (SARS) survivors. METHODS: We evaluated survivors with confirmed SARS at the Prince of Wales Hospital, Hong Kong, at 3, 6, and 12 months after symptom onset. Our assessment included: lung volume (total lung capacity [TLC], vital capacity, residual volume, functional residual capacity), spirometry (FVC, FEV1), diffusing capacity of the lung for carbon monoxide (D(LCO)), inspiratory and expiratory respiratory muscle strength, 6-min walk distance (6MWD), chest radiographs (CXRs), and HRQoL by Medical Outcomes Study 36-Item Short-Form General Health Survey questionnaire. RESULTS: Ninety-seven patients completed the serial assessments. There were 39 male and 58 female patients, and 63 patients (70%) were health-care workers (mean age, 36.9 years [SD, 9.5 years]; body mass index, 23.7 kg/m2 [SD, 4.0 kg/m2]). At 1 year, 27 patients (27.8%) had abnormal CXR findings. Four patients (4.1%), 5 patients (5.2%), and 23 patients (23.7%) had FVC, TLC, and D(LCO) values < 80% of predicted values, respectively. The 6MWD at 12 months was 511.0 m (SD, 89.8 m), which was higher than at 3 months (mean difference, 47.0 m; 95% confidence interval [CI], 31.8 to 62.1 m; p < 0.01) but not different from 6 months (mean difference, 9.7 m; 95% CI, - 4.4 to 23.8 m; p = 0.18). The 6MWD was lower than that for normal control subjects of the same age groups, and there was impairment of HRQoL at 12 months. Patients who required ICU admission (n = 31) showed higher CXR scores (1.6 [SD, 3.1]; vs 0.4 [SD, 1.1]; p = 0.04) and lower percentage of predicted FVC, TLC, and Dlco than those who did not, but there were no differences in 6MWD and health status. CONCLUSION: Significant impairment in Dlco was noted in 23.7% of survivors 1 year after illness onset. Exercise capacity and health status of SARS survivors were remarkably lower than those of a normal population.

Adult↗

PubMed1979

Obstruction of the respiratory pathways, its evaluation by methods of functional examination of the lungs and development in patients with cystic fibrosis.

In 28 patients with cystic fibrosis aged 5--24 years the values of maximum expiratory flow rates (Vmax) at lower volume levels were assessed, as well as the "specific" conductance of the respiratory pathways (Gaw/TGV), the vital capacity (VC), total lung capacity (TLC), residual volume (RV), functional residual capacity (FRC), RV/TLC and FRC/TLC ratios and the one-second forced expiration of the vital capacity (FEV1) to evaluate obstruction of the respiratory pathways. Most markedly and most frequently abnormal were the values of Vmax, RV and of the RV/TLC ratio. These findings revealed that in almost all patients with CF there was already during the initial examination an obstruction of the peripheral respiratory pathways and hyperinflation of the lungs. During repeated measurement of the above values of lung function in 15 patients with cystic fibrosis during a period of 1--5 years when the patients increased in height by 10 cm on average, the above values did not deteriorate on average. There was, however, an individual variability of the investigated values during this period. The comprehensive treatment provided in our country prevented in patients with CF a deterioration of obstruction of the respiratory pathways during the period of investigation.

Adolescent↗

PubMed2003

Effects of rapid saline infusion on lung mechanics and airway responsiveness in humans.

Lung mechanics and airway responsiveness to methacholine (MCh) were studied in seven volunteers before and after a 20-min intravenous infusion of saline. Data were compared with those of a time point-matched control study. The following parameters were measured: 1-s forced expiratory volume, forced vital capacity, flows at 40% of control forced vital capacity on maximal (Vm(40)) and partial (Vp(40)) forced expiratory maneuvers, lung volumes, lung elastic recoil, lung resistance (Rl), dynamic elastance (Edyn), and within-breath resistance of respiratory system (Rrs). Rl and Edyn were measured during tidal breathing before and for 2 min after a deep inhalation and also at different lung volumes above and below functional residual capacity. Rrs was measured at functional residual capacity and at total lung capacity. Before MCh, saline infusion caused significant decrements of forced expiratory volume in 1 s, Vm(40), and Vp(40), but insignificantly affected lung volumes, elastic recoil, Rl, Edyn, and Rrs at any lung volume. Furthermore, saline infusion was associated with an increased response to MCh, which was not associated with significant changes in the ratio of Vm(40) to Vp(40). In conclusion, mild airflow obstruction and enhanced airway responsiveness were observed after saline, but this was not apparently due to altered elastic properties of the lung or inability of the airways to dilate with deep inhalation. It is speculated that it was likely the result of airway wall edema encroaching on the bronchial lumen.

Administration, Inhalation↗

PubMed1982

Effect of pneumatic trousers on pulmonary function.

Little information is available concerning the effect of pneumatic antishock trousers (PT) on pulmonary function. To examine this issue, we measured the effects of PT inflation on forced expired volumes, subdivisions of lung volumes, quasistatic lung compliance, single-breath diffusing capacity for carbon monoxide, and transdiaphragmatic pressure at resting lung volume in 10 healthy nonsmoking adults. All subjects were studied seated without PT, supine with PT uninflated, and supine with PT inflated to 100 mm Hg. When seated subjects assumed the supine position without PT inflation, significant reductions were found in the forced expired volume in 1 sec, in subdivisions of lung volume, total lung capacity (TLC), functional residual capacity (FRC), expiratory reserve volume (ERV) and in transdiaphragmatic pressure. However, PT inflation itself did not produce significant changes in any of the measured pulmonary indices except transdiaphragmatic pressure. We conclude that PT inflation in supine normovolemic individuals does not produce acutely significant alterations in lung function.

Adult↗

PubMed1993

Operative creation of left to right cardiac shunts: pulmonary functional sequelae.

The creation of left to right cardiac shunts in neonates is frequently complicated by pulmonary morbidity in the immediate postoperative course. To elucidate the pattern, severity, and cause of lung dysfunction, pulmonary function testing was performed preoperatively and 1, 3, and 7 days postoperatively on 7 neonates undergoing Blalock-Taussig shunting. Pulmonary mechanics (compliance, conductance) were determined with esophageal manometry and pneumotachography, and functional residual capacity was measured by the helium dilution technique. The infants had pulmonary function preoperatively that was similar to that of healthy term neonatal controls. Significant decreases in compliance, conductance, and functional residual capacity were found on the first postoperative day (57%, 21%, and 53% of predicted, respectively). Alterations in conductance were more severe than those in compliance, but both were low through postoperative day 3. Functional residual capacity was the least affected parameter and recovered by postoperative day 3. All parameters were normal by postoperative day 7. These data indicate that shunting is associated with pulmonary morbidity through the third postoperative day that affects the airways more than the lung parenchyma. Pulmonary function studies of these infants may clarify the etiology of pulmonary dysfunction and have an impact on therapeutic strategies used in neonates undergoing cardiac operations.

Heart Defects, Congenital↗

PubMed1987

Longitudinal changes in lung function and respiratory symptoms in progressive systemic sclerosis. Prospective study.

Most patients with progressive systemic sclerosis (PSS) exhibit lung involvement. However, the natural history of lung disease in PSS remains poorly defined. To evaluate lung function over time in PSS, a battery of lung function tests were prospectively performed serially between 1973 and 1982 in 61 patients with PSS. Functional indexes of restriction (vital capacity and total lung capacity) and diffusion impairment (diffusing capacity) showed greater-than-expected annual rates of change. Male subjects showed a trend toward faster declines in forced vital capacity, forced expired volume in one second, total lung capacity, and functional residual capacity and a more rapid increase in static recoil pressure at 90 percent of total lung capacity than did female subjects. Nonsmokers had greater rates of decline in total lung capacity and static lung compliance (but not in forced vital capacity or diffusing capacity) and a greater rate of increase in static recoil pressure than did current and former smokers. Level of lung function at initial study visit, age, race, and chlorambucil therapy had no significant effect on the annual rates of change in lung function, whereas longer duration of disease prior to study entry was associated with a slower annual decrease in lung volumes. Between the first and last visits (mean interval 3.1 years, maximum nine years), the frequency of abnormality in pulmonary function test results showed significant change only in the diffusing capacity (60 percent increasing to 82 percent) and static lung compliance (40 percent increasing to 54 percent), whereas the frequency of respiratory symptoms showed little change. These findings indicate an overall indolent progression of PSS-related lung disease, with substantial individual variability.

Adult↗

PubMed1987

[Follow-up of patients with burn injuries following long-term ventilation].

Follow-ups were performed five years post burn on 13 severely burned patients after long-term ventilation in order to identify damage to the trachea and lung. The study comprised clinical examination, tracheal X-rays, pulmonary function tests with whole-body plethysmography for thoracic compliance, and spiroergometry. Tracheal stenosis was detected in five patients (38%), two patients had reduced total lung capacity and functional residual capacity was increased. Six patients had high values of pulmonary resistance. The comparison between actual and predicted physical work capacity in the spiroergometry showed a reduction below 85% of normal in five patients, but only one patient had a marked low output (51%). It is remarkable that patients after long-term ventilation, even after inhalation trauma have only minimal impairment of pulmonary function and physical work capacity five years after trauma. The high incidence of tracheal-stenosis after tracheotomy has to be considered as a serious finding.

Burns, Inhalation↗

PubMed1995

Impairment of lung volumes and respiratory muscle strength in adult patients with growth hormone deficiency.

Little is known of the respiratory function in patients with growth hormone (GH) deficiency. The aim of the present study was to evaluate lung volumes and respiratory muscle strength in patients diagnosed as GH deficient in childhood. Ten patients diagnosed as GH deficient in childhood and ten healthy subjects entered the study. For each subject the evaluation of respiratory function followed the same standard approach, consisting of respiratory muscle strength assessment, recording of flow-volume curves, measurement of static lung volumes and lung diffusing capacity. Both maximal inspiratory and expiratory mouth pressures were decreased in GH deficiency. Vital capacity, N2 functional residual capacity and total lung capacity were significantly reduced when compared to healthy subjects. Conversely, the residual volume and diffusing lung capacity to CO did not show any significant change. No significant change of percentage forced expiratory volume in 1 s/forced vital capacity ratio was observed. The decrease of respiratory mouth pressures was not correlated to the decrease of lung volumes. In conclusion, the results of this study show that adult patients affected with childhood onset GH deficiency suffer from impairment of ventilatory function and a decrease of respiratory muscle pressures, probably due to reduction of respiratory muscle strength.

Adult↗

PubMedDate not supplied

Exposure to environmental tobacco smoke in the household and urinary cotinine excretion, heavy metals retention, and lung function.

The relationship between urinary levels of cotinine (U-cotinine) and arsenic (U-As), blood levels of cadmium (B-Cd), blood levels of lead (B-Pb), lung function, and questionnaire data on smoking habits were studied in 107 parents and their 46 children (7-10 y of age). There was a statistically significant relationship between the reported amount of tobacco smoked and U-cotinine levels. Nonsmokers who were married to persons who smoked had three times higher U-cotinine levels than nonsmokers whose spouses did not smoke. There was a significant association between the number of parents who smoked in the family and the U-cotinine levels of children. If only one parent smoked, maternal smoking was of greater importance than paternal smoking. There was also an association between U-cotinine and B-Cd. A study of lung function in the children revealed that vital capacity and functional residual capacity (corrected for sex, age, and height) increased as the number of parents who smoked increased. Therefore, the present study showed that (1) U-cotinine was a useful index of active smoking and environmental tobacco smoke exposure in adults and children, (2) U-cotinine was associated with the blood concentration of cadmium, and (3) environmental tobacco smoke exposure was associated with changes in lung function of children.

Adult↗

PubMed1998

AANA Journal course: update for nurse anesthetists--the preoperative pulmonary assessment: is this patient at high risk for surgery?

Postoperative pulmonary complications most often involve atelectasis followed by pneumonia and arterial hypoxemia. The severity of these complications is related to the decreases that occur in vital capacity and functional residual capacity. Astute anesthetists can prospectively identify patients and surgical procedures likely to be associated with pulmonary complications. Upper abdominal surgery carries a 30% to 40% pulmonary complication rate. Vertical laparotomies and lateral thoracotomies are associated with pulmonary risk, as are patients who are obese, emphysemic, asthmatic, or have cardiac disease. Optimal use of clinical data coupled with selective application of diagnostic tests, such as arterial blood gases and pulmonary function tests, help in the development of an appropriate anesthetic management plan that minimizes pulmonary risk, especially in patients with known pulmonary risk factors.

Humans↗

PubMed1995

Mechanical and morphometrical changes in progressive bilateral pneumothorax and pleural effusion in normal rats.

Respiratory changes resulting from stepwise intrathoracic injections of 4 ml of either room air or warm (37 degrees C) Haemaccel, simulating pneumothorax and pleural effusion, respectively, were evaluated in anaesthetized, paralysed, and mechanically-ventilated rats. Respiratory system, lung, and chest wall resistances and elastances (static and dynamic) were determined in 14 animals. For this purpose, the end-inflation occlusion during constant inspiratory flow method was used. Chest wall configuration at both functional residual capacity (FRC) and end-inspiration tidal volume (i.e. FRC+(VT)) was also evaluated in: 1) 15 rats by measurements of lateral and anteroposterior diameters, and circumferences at the 3rd intercostal space and xiphoid levels; and 2) in 16 rats by measurements of thoracic cephalocaudal diameter. In addition, changes in functional residual capacity were measured. Both in pneumothorax and pleural effusion, resistances were not altered, but static and dynamic respiratory system and lung elastances increased progressively. Morphometric changes were similar at both functional residual capacity and end-inspiration; however, whereas pleural effusion increased all diameters, pneumothorax did not modify lateral diameter. Functional residual capacity was decreased in both conditions. In conclusion, pneumothorax and pleural effusion induced similar mechanical changes, but thoracic configuration was differently affected, since lateral diameters were increased in pleural effusion only.

Animals↗

PubMed2000

Airway closure with high PEEP in vivo.

When airway smooth muscle is contracted in vitro, the airway lumen continues to narrow with increasing concentrations of agonist until complete airway closure occurs. Although there remains some controversy regarding whether airways can close in vivo, recent work has clearly demonstrated that, if the airway is sufficiently stimulated with contractile agonists, complete closure of even large cartilaginous conducting airways can readily occur with the lung at functional residual capacity (Brown RH and Mitzner W. J Appl Physiol 85: 2012-2017, 1998). This result suggests that the tethering of airways in situ by parenchymal attachments is small at functional residual capacity. However, at lung volumes above functional residual capacity, the outward tethering of airways should increase, because both the parenchymal shear modulus and tethering forces increase in proportion to the transpulmonary pressure. In the present study, we tested whether we could prevent airway closure in vivo by increasing lung volume with positive end-expiratory pressure (PEEP). Airway smooth muscle was stimulated with increasing methacholine doses delivered directly to airway smooth muscle at three levels of PEEP (0, 6, and 10 cmH(2)O). Our results show that increased lung volume shifted the airway methacholine dose-response curve to the right, but, in many airways in most animals, airway closure still occurred even at the highest levels of PEEP.

Animals↗

PubMed1980

A comparison of the effects of paraquat and diquat on lung compliance, lung volumes and single breath diffusing capacity in the rat.

Paraquat intoxication in its initial stage is characterized histologically in the lungs by atelectasis, hyaline membrane formation, alveolar edema and vascular hemorrhage often into the interstitium or air spaces. Information on the functional modification of paraquat-damaged lungs has been lacking. We evaluated lung volumes, single breath diffusing capacity of the lungs for carbon monoxide (DLCO) and static lung compliance (Cst(L)) in rats treated with paraquat or diquat. Measurements were made 12, 24, 48, and 72 h after treatment. Paraquat by intratracheal (i.t.) instillation 0.5 mg/kg or by intraperitoneal injection (i.p.) 27 mg/kg significantly decreased (P less than 0.01) the body weight, total lung capacity (TLC), functional residual capacity (FRC), vital capacity (VC), residual volume (RV), DLCO, apparent alveolar volume (VA) and Cst(L). At a lower dose level (13.5 mg/kg), the effects of paraquat peaked at about 24 h following treatment, causing a significantly decreased (P less than 0.01) VC and TLC. Diquat i.t. or i.p. had little effect on the lungs. However, diquat i.p. decreased body weight (P less than 0.01) and caused a slight increase (P less than 0.05) in VC. The data obtained are consistent with the known pathological changes seen in paraquat-damaged lungs in that, by both routes, paraquat caused severe lung damage associated with decreased elasticity of the lungs and thorax, destruction of gas exchanging alveolar surfaces, and edema. These changes were detected reliably by lung function measurements.

Animals↗

PubMedDate not supplied

Airway responses to 2.0 ppm nitrogen dioxide in normal subjects.

Nitrogen dioxide (NO2) is a common indoor air pollutant. To characterize the acute respiratory responses to this gas, 18 nonsmoking normal subjects (mean age +/- standard deviation [SD] = 25 +/- 4 yr) were exposed to filtered air or 2 ppm NO2 gas for 1 hr in a 30-m3 environmental chamber on different days, typically 1 wk apart, in a double-blind randomized fashion. Lung function tests included forced vital capacity, forced expiratory volume in one second, partial expiratory flow at 40% of vital capacity (Vp40), functional residual capacity, and specific airway conductance, and were measured before and after exposure. Airway reactivity to methacholine inhalation was determined within 45 min of each exposure. The dose of methacholine in mg/ml to cause a 40% decrease in specific airway conductance (PD40) was measured. Airway reactivity to methacholine aerosol increased significantly after NO2, which is shown by a decrease in the concentration of methacholine; PD40 (AIR) = 101 +/- 44, PD40 (NO2) = 81 +/- 45 mg/ml, p = .003. No significant changes were noted in the lung function tests after NO2 exposure. These findings indicate that normal nonsmokers exposed to 2.0 ppm NO2 for 1 hr develop an increase in airway reactivity to methacholine aerosol, which is not associated with changes in lung volumes, flow rates, or respiratory symptoms.

Adolescent↗

PubMed1995

Relationship of peak flow rate and peak velocity time during voluntary coughing.

The differences in phonation between men and women are thought to occur from anatomical differences in the larynx. However, it is not known if there are any differences in cough dynamics between the sexes. We investigated this by asking 100 healthy, non-smoking adults (50 male) to perform a voluntary cough into a tussometer. Each volunteer coughed at four different lung volumes, ranging from total lung capacity to functional residual capacity. There was a positive correlation between peak velocity time and cough peak flow rate in both males (r = 0.73, P < 0.001) and females (r = 0.78, P < 0.001). Multiple regression analysis showed that height (P < 0.05) and sex (P < 0.001) were significant determinants of the relationship between peak flow rate and peak velocity time. In a height-matched subgroup, sex differences remained significant (P < 0.05). This may be related to anatomical differences in laryngeal structure and may have implications when using tussometry to assess laryngeal function.

Adolescent↗

PubMed1986

Lung function and respiratory muscle strength after propranolol in thyrotoxicosis.

Thirty-five thyrotoxic patients were assessed before treatment, after treatment with propranolol, and after antithyroid drugs. The first group of patients (n = 17) performed the following tests at all three assessment points: forced expiratory volume in the first second (FEV1), vital capacity (VC), functional residual capacity (FRC), residual volume (RV), total lung capacity (TLC), maximal mid-expiratory flow rate (MMFR), diffusing capacity for carbon monoxide (DLCO), and maximum static inspiratory and expiratory mouth pressures (PImax and PEmax). Arterial blood gas analysis was also performed for the first group of patients. No significant changes were seen either after propranolol or after antithyroid drugs in the FRC, RV, TLC, MMFR, DLCO, or blood gases. The remaining 18 patients, group 2, performed only the FEV1, VC, PImax, and PEmax tests at each assessment. The only index of respiratory function that improved significantly after propranolol was PImax (from 46.5 +/- 16.5 to 53.2 +/- 22 cmH2O, p less than 0.01). This suggests that adrenergic excess may play a role in thyrotoxic inspiratory muscle weakness. After antithyroid drugs, PImax, PEmax, FEV1, and VC all increased significantly as expected.

Adolescent↗

PubMed1997

Computed tomographic measurement of lung density changes in lung water with hemodialysis.

In 10 hemodialysis patients, with an ultrafiltration volume ranging from 1 to 4.5 liters per session, the lung density was measured by computed tomography (CT) and the lung volumes by total body plethysmography. From the CT numbers (difference in X-ray attenuation between lung and water, measured in Hounsfield units, HU), and by using a special computer program, quantitative estimates of the densities of normally inflated (pixels between -1,000 and -500 HU), poorly inflated (pixels between -500 and -100 HU) and noninflated lung tissue (pixels between -100 and +100 HU) were obtained. The sizes of the normally and poorly inflated areas were also measured. The results showed that, after dialysis, the normally inflated area was decreased in density and increased in size, and conversely, the size of the poorly inflated area was diminished but without change in density. This finding implied introduction of more gas into the lung. The above observation was reflected by the results of pulmonary function measurements, in that the total lung capacity and functional residual capacity were significantly increased after dialysis. In conclusion, changes in lung fluid (both intra- and extravascular) with hemodialysis can be measured quantitatively by the changes in lung density as estimated by the CT densitometry technique.

Adult↗

PubMed1987

Ventilatory muscle dysfunction in patients with bilateral idiopathic diaphragmatic paralysis: reversal by intermittent external negative pressure ventilation.

Bilateral idiopathic diaphragmatic paralysis (BIDP) may result in progressive ventilatory failure. To test the hypothesis that this is in part due to dysfunction of overtaxed inspiratory muscles, we studied 3 patients with BIDP before and after 2, 5, and 18 wk of daily intermittent external surface negative pressure ventilation (ENPV). The patients were evaluated using a zero to 10 functional score (FS) that graded dyspnea, orthopnea, capacity to perform activities of daily living, and ability to work. Pleural (Ppl), abdominal (Pab), and transdiaphragmatic (Pdi) pressures were used as an index of respiratory muscle function. All patients improved their functional score (FS increased 2, 6, and 6, respectively) and their pressure generating ability (Pplmax increased -18, -37, and -46 cm H2O, respectively). Forced vital capacity and functional residual capacity increased in the 2 patients ventilated for longer than 2 wk. These results indicate that ventilatory muscle dysfunction may result from chronic increased work of the inspiratory muscles and that it may improve after periods of intermittent ENPV. This may occur as early as 2 wk after initiation of therapy.

Adult↗