Does negative expiratory pressure (NEP) during spontaneous breathing predict respiratory impairment in elderly?

OBJECTIVE: The purpose of this study is to assess whether expiratory flow limitation (FL), as measured by applying a negative pressure at the mouth during tidal expiration, can evaluate the respiratory impairment in elderly patients. METHODS: The study was carried out in 67 consecutive elderly inpatients (24 men and 43 women). Negative expiratory pressure (NEP) of -5 (NEP 5) and -10 (NEP 10) cm H2O were applied during spontaneous tidal expiration. According to the results of the NEP technique, the patients were stratified in two categories: not flow limited and flow limited. We realized then classic forced expiratory manoeuvres (FEV1, FVC) and clinical evaluation of dyspnea (NYHA). According to the values of the lung function data, elderly patients were then divided in 3 groups (normal, obstructive, restrictive). RESULTS: The sensitivity, the specificity, the positive and negative predictive values for the diagnosis of obstructive syndrome by the presence of flow limitation during NEP 5 were 53, 74, 45, 79% respectively and 58, 83, 58, 83% respectively during NEP 10. These findings show that the correlation between FL obtained by the NEP technique during spontaneous breathing and spirometry is not very good despite the fact that both were well correlated with dyspnea score. CONCLUSIONS: In clinical practice, faced with an elderly dyspneic patient unable to perform maximal expiratory manoeuvres, the evaluation of flow limitation by NEP technique seems nor to be reliable to predict an obstructive functional impairment nor to be able to explain the origin of his dyspnea.

Comparison of FEV1 and specific airway conductance in assessing airway response to occupational agents.

BACKGROUND: There is theoretical evidence that specific airway conductance (SGaw) could be more reliable than forced expiratory volume in 1 s (FEV1) for assessing changes in airway calibre. We investigated the changes in FEV1 and SGaw when assessing bronchial responses to occupational agents. METHODS: SGaw and FEV1 were measured during inhalation challenges with various occupational agents in 174 consecutive subjects investigated for possible occupational asthma. RESULTS: A decline in SGaw of 50% or greater was documented in 77 of 90 subjects (86%) who showed a >/=20% fall in FEV1 and in 11 of 84 subjects (13%) who failed to demonstrate such a fall in FEV1. Among subjects who developed a >/=20% fall in FEV1, those who failed to develop a >/=50% decline in SGaw had a lower baseline SGaw than those who did. Among the group without a >/=20% fall in FEV1, a >/=50% decrease in SGaw was associated with either an 'intermediate' fall in FEV1 (between 15 and 17% from baseline value) (n = 4), a significant postchallenge increase in nonspecific bronchial hyper-responsiveness to histamine (n = 2), or both features (n = 3). CONCLUSIONS: A decline in SGaw of 50% or greater may provide useful complementary evidence of a bronchial response during challenges that produce equivocal results in FEV1.

Does negative expiratory pressure influence performances of spirometry in older patients?

The aim of this study is to assess the influence of the negative expiratory pressure (NEP) technique on the performance of maximal expiratory manoeuvre in elderly patients. Firstly, the authors studied how NEP (at 5 and 10 cmH2O, NEP5 and NEP10) influences forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) in 60 young healthy volunteers, in order to assess the fluctuations of the method. In the second part of the study, 65 successive elderly inpatients (>70 yrs old) were examined. In this group, 15 elderly patients were unable to perform the manoeuvre, 27 had a normal function, 14 had a lung function with obstructive pattern and nine with restrictive pattern. In young subjects, FVC during NEP5 and NEP10 compared to baseline values was 101+/-5%, and 103+/-5%, respectively, and FEV1 was 100+/-4% and 101+/-5%, respectively. In elderly patients with normal function, FVC during NEP5 and NEP10 compared to baseline values was 99+/-14% and 109+/-23%, respectively, and FEV1 was 97+/-9% and 104+/-13%, respectively. There were no relevant effects of the NEP application on FVC or FEV1 values in elderly patients with an obstructive or restrictive pattern. In elderly patients, the use of the negative expiratory pressure technique during maximal expiratory manoeuvres provides little complementary information compared to a classical manoeuvre. The negative expiratory pressure technique did not modify the initial diagnosis when compared with the classical manoeuvre.

[Diagnostic approach occupational asthma]. / Approches diagnostiques de l'asthme professionnel.

Occupational asthma is associated with significant medical and socioeconomic consequences. Therefore, the diagnosis should be based on objective and accurate evidence. Available diagnostic procedures include the clinical history, measurement of non-specific bronchial hyperresponsiveness, monitoring of expiratory peak flows at work, and specific inhalation challenges in the laboratory. Advantages and limitations of these tests are discussed in order to propose a pragmatic diagnostic approach where specific inhalation challenges play a central role.

Socioeconomic outcome of subjects experiencing asthma symptoms at work.

The aim of this study was to investigate the socioeconomic outcomes of subjects who experienced work-related asthma symptoms in the absence of demonstrable occupational asthma (OA) and to compare these outcomes with those found in subjects with documented OA. Subjects (n=157) who were being investigated for work-related asthma, were surveyed. Of these 86 had OA, ascertained by a positive specific inhalation challenge (SIC), and 71 subjects had a negative SIC response. After a median interval of 43 months (range 12-85 months), the subjects were interviewed to collect information on employment status, income changes, and asthma-related work disability. Rates of work disruption and income loss at follow-up were similar in subjects with negative SIC (46% and 59%, respectively) and in those with OA (38% and 62%). The median loss as a percentage of initial income was 23% in subjects with negative SIC and 22% in subjects with OA. Asthma-related work disability, defined as any job change or work loss due to asthma, was slightly more common in subjects with OA (72%) than in those with negative SIC (54%). This study shows that, even in the absence of demonstrable occupational asthma, work-related asthma symptoms are associated with considerable socioeconomic consequences.

Comparison of peak expiratory flows and FEV1 in assessing immediate asthmatic reactions due to occupational agents.

BACKGROUND: FEV1 is more sensitive than PEF in assessing late asthmatic responses (LAR) after specific inhalation challenges (SIC) with occupational agents. As immediate asthmatic reactions (IAR) mainly involve proximal airways, PEF may, however, be as valid as FEV1. METHODS: Thirty-seven subjects who experienced an immediate fall in FEV1 of > or =20% during SIC with occupational agents and 20 subjects with fall of < or =10% in FEV1 were included. Both FEV1 and PEF were measured in a random order every 10 min for 1 h after exposure. We corrected PEF (PEFc) for inaccuracies of the mini-Wright meters by the Miller equation. RESULTS: Maximum changes in PEFc (30+/-11%) were not significantly different from changes in FEV1 (27+/-5%) (P=0.13). Their timings after exposure were 14+/-11 min and 17+/-17 min, respectively (P=0.4). High sensitivity (92%), specificity (95%), accuracy (93%), and positive predictive value (97%) were found for a 20% fall in PEFc to detect a significant IAR. Results were better and not influenced by meter inaccuracies with a cutoff point of 15% change in noncorrected PEF (PEFnc). An absolute decrease in PEF of 70 l/min gave a good discrimination between reactions with and without an asthmatic response. CONCLUSIONS: PEF is as satisfactory as FEV1 for detecting a significant IAR after exposure to an occupational agent if one considers a cutoff point of 1) 15% fall in PEF 2) 20% fall in PEFc 3) 20% fall and/or 70 l/min decrease in PEFnc.

Pulmonary effects of short-term exposure to low levels of toluene diisocyanate in asymptomatic subjects.

Isocyanates may be involved in the development of chronic obstructive airway disease among exposed workers. A short-term exposure to toluene diisocyanate (TDI) at concentrations near the permissible levels was investigated to examine whether there was an association with changes in pulmonary function tests and in potential markers of airway injury and inflammation in bronchial lavage (BL) and bronchoalveolar lavage (BAL). Seventeen subjects without respiratory symptoms (eight smokers and nine nonsmokers) were exposed once to ambient air and once to TDI (5 parts per billion (ppb) for 6 h followed by 20 ppb for 20 min) in a randomized, single-blind sequence. Pulmonary function tests were repeatedly assessed during exposure and BAL was performed 1 h after each exposure. Biochemical studies on lavage fluids included albumin, immunoglobulins, antiproteases (alpha2-macroglobulin and alpha1-proteinase inhibitor), potential indicators of epithelial cell function (secretory component and Clara cell protein), and cytokines (tumour necrosis factor-alpha, interleukin (IL)-4, IL-5, IL-6, and IL-8). Exposure to TDI caused a modest decrease in specific airway conductance (sGaw) (p=0.053) and in maximal expiratory flow at 25% of forced vital capacity (MEF25%) (p=0.015) when compared with ambient air. Exposure to TDI resulted in a slight increase in BAL albumin level (TDI: 26.4+/-12.5 versus air: 21.8+/-8.6 microg x mL(-1), p=0.044) and in BL alpha2-macroglobulin concentration (TDI: 0.07+/-0.061 versus air: 0.05+/-0.04 microg x mL(-1), p=0.021). This study suggests that exposure to low toluene disocyanate concentrations is associated with minimal but detectable changes in airway calibre and in epithelial barrier permeability. The pulmonary effects of long-term exposure to low levels of isocyanates require further investigation.

Occupational asthma caused by aluminium welding.

Work-related asthma has been documented in workers employed in the primary aluminium industry and in the production of aluminium salts. The role of aluminium in the development of occupational asthma has, however, never been convincingly substantiated. We investigated a subject who experienced asthmatic reactions related to manual metal arc welding on aluminium. Challenge exposure to aluminium welding with flux-coated electrodes, as well as with electrodes without flux, elicited marked asthmatic reactions. Manual metal arc welding on mild steel did not cause significant bronchial response. The results of inhalation challenges combined with exposure assessments provided evidence that aluminium can cause asthmatic reactions in the absence of fluorides. Awareness of this possibility may be relevant to the investigation of asthma in workers exposed to aluminium.

Increase in non-specific bronchial hyperresponsiveness as an early marker of bronchial response to occupational agents during specific inhalation challenges.

BACKGROUND: Specific bronchial reactivity to occupational agents may decline after exposure in the workplace ceases leading to falsely negative specific inhalation challenges. A study was carried out to assess prospectively whether increases in nonspecific bronchial hyperresponsiveness could be useful in detecting the bronchial response to occupational agents during specific inhalation challenges. METHODS: Specific inhalation challenges were performed in 66 subjects with possible occupational asthma due to various agents. After a control day the subjects were challenged with the suspected agent for up to two hours on the first test day. Those subjects who did not show an asthmatic reaction were rechallenged on the next day for 2-3 hours. The provocative concentration of histamine causing a 20% fall (PC20) in the forced expiratory volume in one second (FEV1) was assessed at the end of the control day as well as six hours after each challenge that did not cause a > or = 20% fall in FEV1. The subjects who had a significant (> or = 3.1-fold) reduction in PC20 value at the end of the second challenge day were requested to perform additional specific inhalation challenges. RESULTS: The first test day elicited an asthmatic reaction in 25 subjects. Of the other 41 subjects five (12%, 95% confidence interval (CI) 4% to 26%) exhibited a > or = 3.1-fold fall in the PC20 value after the inhalation challenge and developed an asthmatic reaction during the second (n = 3) or third (n = 2) challenge exposure. The offending agents included persulphate (n = 1), wood dust (n = 2), isocyanate (n = 1), or amoxycillin (n = 1). These five subjects had left their workplace for a longer period (mean (SD) 21 (14) months) than those who reacted after the first specific inhalation challenge (8 (11) months). CONCLUSIONS: The increase in non-specific bronchial hyperresponsiveness after a specific inhalation challenge can be an early and sensitive marker of bronchial response to occupational agents, especially in subjects removed from workplace exposure for a long time. Non-specific bronchial hyperresponsiveness should be systematically assessed after specific inhalation challenges in the absence of changes in airway calibre.

Occupational asthma due to latex in a hospital administrative employee.

A case is described of occupational asthma caused by indirect exposure to airborne latex allergens in an administrative hospital employee who never used latex gloves.

Latex gloves with a lower protein content reduce bronchial reactions in subjects with occupational asthma caused by latex.

Latex gloves have been documented as causing rhinitis and asthma. Using inhalation challenges, we evaluated the bronchial response to hypoallergenic gloves in eight health care workers with latex-induced asthma. The subjects were exposed to the powdered latex gloves causing asthma at work and various brands of gloves with a lower protein content, either low-powdered, nonpowdered, or powdered. Exposure to hypoallergenic gloves resulted in the absence (in six subjects) or a significant reduction (in two subjects) of bronchial response. The effects of repeated exposure to hypoallergenic gloves was assessed in two subjects who did not demonstrate changes in peak expiratory flow rates and nonspecific bronchial responsiveness to histamine. This study on a limited number of patients suggests that the use of hypoallergenic gloves could be an effective means of reducing the risk of asthmatic reactions in health care workers with latex-induced asthma when complete avoidance cannot be achieved. The long-term effect of exposure as well as the widespread use of hypoallergenic gloves warrant further investigation on larger cohorts of subjects.

Prevalence of occupational asthma due to latex among hospital personnel.

Latex has been documented as causing immediate hypersensitivity reactions ranging from contact urticaria to severe anaphylaxis. Latex proteins may also act as airborne allergens causing rhinitis and asthma. The prevalence of occupational asthma due to latex gloves among health care workers is unknown. We surveyed the employees of a primary care hospital including nurses (n = 201), members of the cleaning staff (n = 50), and laboratory technologists (n = 38). In the initial part of the study, a questionnaire and skin-prick tests with latex and common inhalant allergens were administered to 273 of 289 (94%) members of the target population. Thirteen of the 273 subjects (4.7%; 95% CI: 2.6 to 8.1%) showed skin reactivity to latex. All latex-sensitive subjects reported glove-related urticaria, which was associated with rhinoconjunctivitis in 12 subjects and asthma in five subjects. No subject had a history suggestive of occupational asthma among those who had negative skin tests to latex. In the second part of the study, a histamine inhalation challenge was performed on 12 of 13 latex-sensitive subjects, including the five subjects with a history of occupational asthma. These 12 subjects demonstrated significant bronchial hyperresponsiveness. All underwent specific inhalation challenges with latex gloves in the laboratory. Seven subjects developed a significant bronchial response (four immediate and three dual reactions) to latex glove exposure. We conclude that occupational asthma due to latex occurred in 2.5% (95% CI: 1.0 to 5.2%) of hospital employees. Widespread use of latex gloves should therefore be considered a significant risk to the respiratory health of hospital employees.

Bronchoalveolar lavage immunoglobulin A and G and antiproteases correlate with changes in diffusion indices during the natural course of pulmonary sarcoidosis.

We wanted to determine whether cell populations and soluble components in bronchoalveolar lavage (BAL) could be useful in predicting the outcome of lung function and chest radiography in patients with untreated pulmonary sarcoidosis. Analysis of soluble proteins in BAL fluid, included the levels of immunoglobulins and the two major antiproteases, alpha 2-macroglobulin (alpha 2-M) and alpha 1-protease inhibitor (alpha 1-PI), expressed as a relative coefficient of excretion (RCE). Thirty one nonsmoking patients with biopsy proven sarcoidosis, who remained untreated, had reassessment of lung function tests after 6-54 months (median 21 months). No correlation was observed between initial BAL data and changes in lung volumes and radiographic opacities. By contrast, the initial BAL immunoglobulin A and G (IgA and IgG) RCE correlated inversely with the change in transfer factor for carbon monoxide (TLCO) in the whole group and in patients with sarcoidosis of recent origin (estimated disease duration < 6 months). In the whole group and in patients with longstanding disease (estimated disease duration > 24 months, or radiographic Stage 4), the change in carbon monoxide transfer coefficient (KCO) correlated negatively with the initial alpha 1-PI RCE and positively with the initial helper to suppressor T-cell (T4/T8) ratio. By contrast, no significant difference in BAL cellular and protein data was found between patients with recent and longstanding sarcoidosis.(ABSTRACT TRUNCATED AT 250 WORDS)