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Importance of the Time Interval Between FEV1, Measurements in a Methacholine Provocation Test
---4.1 MlJA II
Abstracts from The European Respirator, Journal
Reliability of a Monitoring System for Respiratory Emergency Room Admissions F. Martinez, J Sunyer, J M. Anto. Eur Bespir J, 1993; 6:337-341. ABSTRACT: A respiratory emergency room admissions monitoring system (RERAMS) was set up in Barcelona between 1985-1989, in order to investigate asthma epidemics in the city. Information on emergency room admissions for asthma and chronic obstructive pulmonary disease (COPO) was recorded daily from the four main hospitals of the city. The present study aims at assessing the reliability and coverage of this monitoring system. Identification of asthma and CO PO emergencies was repeated by a reference observer, following the same protocol to extract data as that used by the register. To assess the coverage of the monitoring system, infonnation was collected over 28 randomly selected days, from the emergency room clinical records for the seven additional hospitals in the city with five or more daily emergencies. Identification of asthma emergencies was highly reliable (kappa value, K = 0.81) as was the discrimination between asthma and COPO diagnoses (K = 0.91). Reliability for emergencies classified as COPD was lower, but still good (K = 0.65). The monitoring system covered 76 and 78% of all Barcelona asthma and COPO emergency room admissions, respectively. Emergency room admissions from our monitoring system did not differ in terms of social and demographic characteristics from emergencies recorded at the other hospitals. We conclude that the monitoring system for the Barcelona respiratory emergency room admissions was highly reliable, which suggests that, when adequately collected, infonnation from clinical records of respiratory emergencies could be used for environmental epidemiological purposes. Correspondence: J M. Anto, Departament d'Ef)idemiologia i Salut Publica, lnstitut Municipal d'lnvestigaciO Medica, R Maritim, 2529, 08003 Barcelona, Spain.
Parenchymal Emphysema Measured by CT Lung Density Correlates With Lung Function in Patients With Bullous Disease G. A. Gould, A. 1: Redpath, M. Ryan, R M. Wa1"Ten, J E. J W Cameron, W MacNee. Eur Respir J, 1993, 6:698-704.
J
K. Best,
ABSTRACT: In subjects with chronic obstructive pulmonary disease (COPO) computed tomographic (CT) lung density correlates with direct pathological measurements of the size of the distal airspaces, as well as with measurements of airflow limitation and impairment of the diffusing capacity. Thus, CT lung density can be used to quantify emphysema in life. We wanted to assess the use of cr scanning to detect and measure the extent of bullous lung, and to quantify the severity of emphysema in the non-bullous areas of the lungs in patients with bullous emphysema (21 males and 2 females; aged 31-69 yrs; forced expiratory volume in one second (FEV.) 1484% predicted; volume corrected diffusing capacity of the lungs for carbon monoxide (DLCONA) 17-114% predicted). cr lung density A-16
was measured in electromagnetic imaging (EMI) units. The extent of bullous emphysema correlated poorly with all respiratory function measurements. In contrast, the severity of emphysema in the nonbullous parts of the lungs, expressed as either the mean EMI number, or the EMI number of the lowest 5th percentile of the cr lung density histogram, correlated well with measurements of airflow limitation and diffusing capacity. Our findings, thus, suggest that in patients with bullae the major determinant of respiratory function is the severity of the emphysema in non-bullous lung, and that the extent of the bullae has less functional importance. We therefore suggest that cr scanning is useful in the assessment of patients with bullous disease, since it not only accurately defines the extent and site of the bullae, but also assesses the severity of emphysema in the non-bullous regions of the lungs, a factor which may influence respiratory function and the outcome of surgical intervention. Correspondence: W MacNee, Unit of Respiratory Medicine, City Hospital, Edinburgh EH 10 55B, Scotland, UK.
Importance of the Time Interval Between FEV 1, Measurements in a Methacholine Provocation Test R Malmberg, K. Larsson B. M. Sundblad, W Zhiping. Eur Bespir J, 1993, 6:680-686. ABSTRACT: We examined the hypothesis that a forced expiratory volume in one second (FEV.) manoeuvre (and the preceding deep inhalation) before inhalation of methacholine might influence FEV. measured after methacholine, if the time between measurements was short. Six to nine healthy subjects inhaled a single dose of methacholine, known to cause about 20% decrease in FEV., on different days in different test protocols. If an FEV. manoeuvre was performed immediately before methacholine, the first FEV. measured 3 min after provocation was higher (77% of basal FEV.) than if a pre-methacholine FEV. manoeuvre was not performed (64%). This effect of a pre-methacholine FEV. manoeuvre was also demonstrated at 2, 4, and 6, but not at 10 min after the start of methacholine inhalation. If an FEV. manoeuvre was not performed before methacholine, the second and subsequent FEV. measured in constricted airways was higher than the first, and of similar magnitude to the first FEV. in tests where a pre-challenge FEV. manoeuvre was performed. In another trial, 10 healthy subjects performed two stepwise methacholine tests, with either 6 or 3 min between dose steps. The percentage decrease in FEV. per mg of inhaled methacholine decreased from 2.6 (1.9-5.2) to 1.7 (0.8-2.3) (median, interquartile-range) when the time interval was shortened. The results suggest that the deep inhalation associated with the FEV. manoeuvre decreases the bronchial tone in airways constricted by methacholine for up to 6 min, possibly due to yielding of crosslinks in airway smooth muscles. Correspondence: R Malmberg, Respiratory Division, National lnstitute of Occupational Health, S-171 B4, Solna, Sweden.
Continued on page A-21
Abstracts from The European Respirator, Journal
Reliability of a Monitoring System for Respiratory Emergency Room Admissions F. Martinez, J Sunyer, J M. Anto. Eur Bespir J, 1993; 6:337-341. ABSTRACT: A respiratory emergency room admissions monitoring system (RERAMS) was set up in Barcelona between 1985-1989, in order to investigate asthma epidemics in the city. Information on emergency room admissions for asthma and chronic obstructive pulmonary disease (COPO) was recorded daily from the four main hospitals of the city. The present study aims at assessing the reliability and coverage of this monitoring system. Identification of asthma and CO PO emergencies was repeated by a reference observer, following the same protocol to extract data as that used by the register. To assess the coverage of the monitoring system, infonnation was collected over 28 randomly selected days, from the emergency room clinical records for the seven additional hospitals in the city with five or more daily emergencies. Identification of asthma emergencies was highly reliable (kappa value, K = 0.81) as was the discrimination between asthma and COPO diagnoses (K = 0.91). Reliability for emergencies classified as COPD was lower, but still good (K = 0.65). The monitoring system covered 76 and 78% of all Barcelona asthma and COPO emergency room admissions, respectively. Emergency room admissions from our monitoring system did not differ in terms of social and demographic characteristics from emergencies recorded at the other hospitals. We conclude that the monitoring system for the Barcelona respiratory emergency room admissions was highly reliable, which suggests that, when adequately collected, infonnation from clinical records of respiratory emergencies could be used for environmental epidemiological purposes. Correspondence: J M. Anto, Departament d'Ef)idemiologia i Salut Publica, lnstitut Municipal d'lnvestigaciO Medica, R Maritim, 2529, 08003 Barcelona, Spain.
Parenchymal Emphysema Measured by CT Lung Density Correlates With Lung Function in Patients With Bullous Disease G. A. Gould, A. 1: Redpath, M. Ryan, R M. Wa1"Ten, J E. J W Cameron, W MacNee. Eur Respir J, 1993, 6:698-704.
J
K. Best,
ABSTRACT: In subjects with chronic obstructive pulmonary disease (COPO) computed tomographic (CT) lung density correlates with direct pathological measurements of the size of the distal airspaces, as well as with measurements of airflow limitation and impairment of the diffusing capacity. Thus, CT lung density can be used to quantify emphysema in life. We wanted to assess the use of cr scanning to detect and measure the extent of bullous lung, and to quantify the severity of emphysema in the non-bullous areas of the lungs in patients with bullous emphysema (21 males and 2 females; aged 31-69 yrs; forced expiratory volume in one second (FEV.) 1484% predicted; volume corrected diffusing capacity of the lungs for carbon monoxide (DLCONA) 17-114% predicted). cr lung density A-16
was measured in electromagnetic imaging (EMI) units. The extent of bullous emphysema correlated poorly with all respiratory function measurements. In contrast, the severity of emphysema in the nonbullous parts of the lungs, expressed as either the mean EMI number, or the EMI number of the lowest 5th percentile of the cr lung density histogram, correlated well with measurements of airflow limitation and diffusing capacity. Our findings, thus, suggest that in patients with bullae the major determinant of respiratory function is the severity of the emphysema in non-bullous lung, and that the extent of the bullae has less functional importance. We therefore suggest that cr scanning is useful in the assessment of patients with bullous disease, since it not only accurately defines the extent and site of the bullae, but also assesses the severity of emphysema in the non-bullous regions of the lungs, a factor which may influence respiratory function and the outcome of surgical intervention. Correspondence: W MacNee, Unit of Respiratory Medicine, City Hospital, Edinburgh EH 10 55B, Scotland, UK.
Importance of the Time Interval Between FEV 1, Measurements in a Methacholine Provocation Test R Malmberg, K. Larsson B. M. Sundblad, W Zhiping. Eur Bespir J, 1993, 6:680-686. ABSTRACT: We examined the hypothesis that a forced expiratory volume in one second (FEV.) manoeuvre (and the preceding deep inhalation) before inhalation of methacholine might influence FEV. measured after methacholine, if the time between measurements was short. Six to nine healthy subjects inhaled a single dose of methacholine, known to cause about 20% decrease in FEV., on different days in different test protocols. If an FEV. manoeuvre was performed immediately before methacholine, the first FEV. measured 3 min after provocation was higher (77% of basal FEV.) than if a pre-methacholine FEV. manoeuvre was not performed (64%). This effect of a pre-methacholine FEV. manoeuvre was also demonstrated at 2, 4, and 6, but not at 10 min after the start of methacholine inhalation. If an FEV. manoeuvre was not performed before methacholine, the second and subsequent FEV. measured in constricted airways was higher than the first, and of similar magnitude to the first FEV. in tests where a pre-challenge FEV. manoeuvre was performed. In another trial, 10 healthy subjects performed two stepwise methacholine tests, with either 6 or 3 min between dose steps. The percentage decrease in FEV. per mg of inhaled methacholine decreased from 2.6 (1.9-5.2) to 1.7 (0.8-2.3) (median, interquartile-range) when the time interval was shortened. The results suggest that the deep inhalation associated with the FEV. manoeuvre decreases the bronchial tone in airways constricted by methacholine for up to 6 min, possibly due to yielding of crosslinks in airway smooth muscles. Correspondence: R Malmberg, Respiratory Division, National lnstitute of Occupational Health, S-171 B4, Solna, Sweden.
Continued on page A-21