Should we consider paranasal and chest computed tomography in severe asthma patients?

BACKGROUND

It is essential to recognize and treat findings that can simulate or worsen symptoms _to improve asthma control and thereby to reduce costs. Guidelines highlight a paranasal (PS) and chest computed tomography (CT) scan as a tool for disease evaluation and, although they suggest its indication in patients whom presentation is atypical, there are not well-defined criteria.

OBJECTIVES

To describe the most common findings in the PS and chest CT in severe asthma patients and to analyse the characteristics of asthmatics with the finding of nasal polyps or bronchiectasis.

METHODS

We retrospectively reviewed the medical records of 161 adults with confirmed severe asthma who had undergone to PS and/or chest CT. Clinical data from their electronic health record and the findings from a PS and/or chest CT within the last five years were collected.

RESULTS

In the PS CT, 70.5% of patients presented mucous thickening and 46.7% presented nasal polyps. Both findings were associated with male gender and level of blood eosinophils. In chest CT, 28% of individuals showed atelectasis, 16.5% air trapping, 17.7% affectation of the small airway, 11.6% pulmonary infiltrates and 10.4% emphysema. Bronchiectasis were identified in 60.4% of subjects, who were older and had poorer lung function.

CONCLUSION

Paranasal and thoracic computed tomography are important tools in the treatment of severe asthma because they allow us to detect highly prevalent findings in this disease that can lead to poorer control of it.

Value OF CT-Guided Fine Needle Aspiration in Solitary Pulmonary Nodules with Negative Fiberoptic Bronchoscopy

The usefulness of fine needle aspiration (FNA) with CT-guidance was evaluated in the diagnosis of solitary pulmonary nodules (SPN) following negative fiberoptic bronchoscopy in 84 patients. The records were analyzed for all patients with SPN who had undergone chest FNA in the years 1988 to 1990, showing previous nondiagnostic fiberoptic bronchoscopy. A final diagnosis was made by biopsy (transbronchial, thoracotomy or necropsy), response to therapy or follow-up of the lesions. The patients had medium-sized lesions, 2.87 ± 1.11 cm, adherent to the pleura in 62%. In the diagnosis of malignancy FNA showed 76% sensitivity, 100% specificity, 100% positive predictive value, 52% negative predictive value and 81% accuracy. These results were correlated with histology in 84% of the cases. One pulmonary hemorrhage, which resolved spontaneously, and 12 cases of pneumothorax, requiring a thoracic tube in 4 patients, were noted.

Sputum periostin in patients with different severe asthma phenotypes

BACKGROUND

Identifying inflammatory phenotypes is relevant in severe uncontrolled asthma. The aim of this study was to identify the different clinical, inflammatory, functional, and molecular phenotypes in patients with severe asthma and to investigate the potential role of sputum periostin as a biomarker of severe asthma phenotypes.

PATIENTS AND METHODS

Sputum induction was performed in 62 patients diagnosed with severe asthma. Skin prick testing, lung function tests, exhaled nitric oxide, hematimetry, and total serum IgE were performed. Periostin was measured in sputum supernatants.

RESULTS

Patients with asthma were phenotyped and 80% had late-onset asthma, 50% had fixed airflow obstruction, and 66% showed a Th2-high phenotype. With respect to inflammatory phenotypes, 71% were eosinophilic and 25% mixed granulocytic. Periostin levels were higher in patients with fixed as compared to variable airflow limitation (69.76 vs 43.84 pg/ml, P < 0.05) and in patients with eosinophilic as compared to mixed granulocytic phenotype (61.58 vs 37.31 pg/ml, P < 0.05). There was an inverse correlation between postbronchodilator FEV1 /FVC and periostin levels (-0.276, P < 0.05).

CONCLUSION

This study demonstrates the utility of periostin in phenotyping severe asthma. Periostin levels in sputum are associated with persistent airflow limitation in asthma patients with airway eosinophilia despite treatment with high-dose inhaled corticosteroids.

Recent trends in COPD prevalence in Spain: a repeated cross-sectional survey 1997-2007

We aimed to describe changes in the prevalence of chronic obstructive pulmonary disease (COPD) in Spain by means of a repeated cross-sectional design comparing two population-based studies conducted 10 yrs apart. We compared participants from IBERPOC (Estudio epidemiológico de EPOC en España) (n = 4,030), conducted in 1997, with those of EPI-SCAN (Epidemiologic Study of COPD in Spain) (n = 3,802), conducted in 2007. Poorly reversible airflow obstruction compatible with COPD was defined according to the old European Respiratory Society definitions. COPD prevalence in the population between 40 to 69 yrs of age dropped from 9.1% (95% CI 8.1-10.2%) in 1997 to 4.5% (95% CI 2.4-6.6%), a 50.4% decline. The distribution of COPD prevalence by severity also changed from 38.3% mild, 39.7% moderate and 22.0% severe in 1997, to 85.6% mild, 13.0% moderate and 1.4% severe in 2007, and in the 40-69 yr EPI-SCAN sub-sample to 84.3% mild, 15.0% moderate and 0.7% severe. Overall, underdiagnosis was reduced from 78% to 73% (not a significant difference) and undertreatment from 81% to 54% (p<0.05) within this 10-yr frame. The finding of a substantial reduction in the prevalence of COPD in Spain is unexpected, as were the observed changes in the severity distribution, and highlights the difficulties in comparisons between repeated cross-sectional surveys of spirometry in the population.

Exhaled nitric oxide and airway caliber during exercise-induced bronchoconstriction

Data on the relationship between exercise-induced bronchoconstriction (EIB) and exhaled nitric oxide (NO) in adult patients with asthma are controversial. It is unclear whether endogenous NO may act as either a protective or stimulatory factor in the airway response to exercise or whether changes in exhaled NO simply reflect acute narrowing of the airway. The aim of this study was to assess the changes in the fraction of exhaled nitric oxide (FE(NO)) before and after exercise challenge in patients with asthma and to analyze the relationship between FE(NO) and airway obstruction. Twenty-five non-smoking, steroid-naïve, atopic, adult patients with mild persistent asthma and 12 non-smoking, nonatopic, healthy subjects (control group) performed an exercise challenge on a cycloergometer, with monitored ventilation. FEV1 and FE(NO) were measured at baseline and 1, 5, 10, 15 and 20 minutes after the exercise challenge. Eleven of the asthmatic patients had exercise-induced bronchoconstriction (EIB group) and the remaining 14 did not (non-EIB group). Baseline FE(NO) was higher in the EIB and non-EIB asthmatic groups than in the control group. In the EIB group, FE(NO) was significantly lower 5, 10 and 15 minutes after exercise, and the changes in FE(NO) correlated with variation in FEV1 10 and 15 min after exercise. A significant correlation between baseline FE(NO) and maximal post-exercise decrease in FEV1 was found in asthmatic patients (EIB group). In conclusion, exhaled nitric oxide levels transiently decrease during exercise-induced bronchoconstriction in adult patients with asthma. Baseline FE(NO) might predict the airway obstruction resulting after exercise.

Comparison of Carbon Dioxide Rebreathing During Application of Continuous Positive Airway Pressure With 3 Types of Nasal Mask

A comparison is made between the end-tidal fractional concentration of carbon dioxide (FETCO2) obtained during application of varying levels of continuous positive airway pressure (CPAP) with a prototype mask (from Carburos Metálicos) and FETCO2 obtained with 2 commonly used nasal masks (Profile Lite and ComfortClassic from Respironics). The nasal FETCO2 was measured on 3 consecutive days in 11 healthy volunteers, 12 patients with severe obstructive sleep apnea-hypopnea syndrome, and 12 hypercapnic patients. A different mask was randomly assigned on each day and the FETCO2 was measured after 3 minutes of CPAP at 4, 5, 6, 8, 10, 15, and 20 cm H2O. Although in all cases a progressive reduction in FETCO2 was observed with increasing CPAP, the effect was greatest with the prototype mask at all pressures. In the 3 different study groups the pressures obtained with the prototype mask were similar to those generated by the CPAP machine. In conclusion, the lower concentration of nasal CO2 obtained using the prototype mask suggests that it causes less rebreathing.

Cost-effectiveness of formoterol and salbutamol as asthma reliever medication in Sweden and in Spain

This study aimed to evaluate the cost-effectiveness of formoterol (Oxis) Turbuhaler 4.5 microg and salbutamol 200 microg as reliever medications in Sweden and Spain. The study used data on effectiveness (exacerbations and symptom-free days) and resource utilisation from an open, 6-month, parallel-group, multicentre randomised trial with 18,124 asthma patients in 24 countries. Country-specific unit costs for Sweden and for Spain were used to transform resource utilisation data into costs. Total healthcare costs were not significantly different between formoterol and salbutamol dry powder inhalers in Sweden, whereas in Spain, the healthcare costs were 20% higher for formoterol vs. salbutamol pressurised metered dose inhalers. Total healthcare costs increased with disease severity, defined according to the Global Initiative for Asthma guidelines. Compared with salbutamol, formoterol produced statistically significant improvements in effectiveness, less reliever and maintenance medication usage, reduced healthcare resource utilisation, with no increase or a limited increase in healthcare cost.

[Costs of chronic obstructive pulmonary disease in Spain. Estimation from a population-based study]

OBJECTIVE

In the studies carried out to date, the cost of chronic obstructive pulmonary disease (COPD) may have been overestimated due to the inclusion of previously diagnosed patients seeking medical attention for their symptoms. As a result, the severity of the cases included in these studies may have been greater than in an unselected sample of the general population. The aim of the present study was to estimate the direct cost of COPD on the basis of a representative sample of the overall Spanish population between 40 and 69 years of age (from the IBERPOC study).

METHOD

The cost was evaluated retrospectively by means of a questionnaire completed by the 363 patients with COPD from the IBERPOC study with questions referring to the previous year. Standardized spirometry was performed on all the patients by a pneumologist in each of the 7 geographical areas in which the study was carried out.

RESULTS

Hospitalization accounted for the greatest expenditure (41% of total), followed by drug therapy (37%). The cost was euro;98.39 per patient, and euro;909.50 per previously diagnosed patient. The cost per person of severe COPD was more than 3 times that of moderate COPD and more than 7 times that of mild COPD. The estimated annual cost of COPD in Spain was euro;238.82 million (for 1997).

CONCLUSION

The present study, which was the first to estimate the cost of COPD in a representative sample of the general population, found the cost to be lower than in studies analyzing samples of patients with previous diagnoses of COPD. The cost distribution is not in line with recommended health care practices, underlining the need to optimize resources used to monitor and treat the disease, with an emphasis on early diagnosis.

Formoterol as relief medication in asthma: a worldwide safety and effectiveness trial

The aim of the study was to compare the safety and effectiveness of as-needed formoterol with salbutamol in a large international real-life asthma study. Children and adults (n=18,124) were randomised to 6 months as-needed treatment with open-label formoterol 4.5 microg Turbuhaler or salbutamol 200 microg pressurised metered dose inhaler or equivalent. Primary safety variables were asthma-related and nonasthma-related serious adverse events (SAE)s and adverse events (AE)s resulting in discontinuation (DAE)s. The primary efficacy variable was time to first asthma exacerbation. The incidences of AEs, SAEs and DAEs arising from SAEs were not significantly different between treatments. DAEs for nonserious AEs were higher with formoterol. Asthma-related AEs decreased with formoterol (1,098 (12.3%) versus 1,206 (13.5%)), asthma-related SAEs were similar (108 (1.2%) versus 121 (1.4%)) but more asthma-related DAEs occurred in the formoterol group (89 (1.0%) versus 48 (0.5%)). Time to first exacerbation was prolonged (hazard ratio 0.86) and less as-needed and maintenance medication was used with formoterol. Reductions of exacerbations with as-needed formoterol versus salbutamol increased with increasing age and asthma medication level. This real-life study demonstrates that formoterol as-needed has a similar safety profile to salbutamol, and its use as a reliever therapy is associated with fewer asthma symptoms and exacerbations.

Effect of montelukast added to inhaled budesonide on control of mild to moderate asthma

BACKGROUND

Proinflammatory leukotrienes, which are not completely inhibited by inhaled corticosteroids, may contribute to asthmatic problems [corrected]. A 16 week multicentre, randomised, double blind, controlled study was undertaken to study the efficacy of adding oral montelukast, a leukotriene receptor antagonist, to a constant dose of inhaled budesonide.

METHODS

A total of 639 patients aged 18-70 years with forced expiratory volume in 1 second (FEV(1)) > or =55% predicted and a minimum predefined level of asthma symptoms during a 2 week placebo run in period were randomised to receive montelukast 10 mg (n=326) or placebo (n=313) once daily for 16 weeks. All patients received a constant dose of budesonide (400-1600 microg/day) by Turbuhaler throughout the study.

RESULTS

Mean FEV(1) at baseline was 81% predicted. The median percentage of asthma exacerbation days was 35% lower (3.1% v 4.8%; p=0.03) and the median percentage of asthma free days was 56% higher (66.1% v 42.3%; p=0.001) in the montelukast group than in the placebo group. Patients receiving concomitant treatment with montelukast had significantly (p<0.05) fewer nocturnal awakenings and significantly (p<0.05) greater improvements in beta agonist use and morning peak expiratory flow rate (PEFR).

CONCLUSIONS

For patients with mild airway obstruction and persistent asthma symptoms despite budesonide treatment, concomitant treatment with montelukast significantly improves asthma control.

[Respiratory symptoms and diagnosis of COPD in smokers of various types to tobacco. Results from the IBERPOC study]

BACKGROUND

The aim of this study was to investigate the sociodemographic characteristics, smoking habits, the prevalence of respiratory symptoms and chronic obstructive pulmonary disease (COPD) in four groups of smokers: of cigarettes (SCt), of cigars (SCigar), of both (SB), of cigars currently but of cigarettes in the past (SCigarExCt) and of cigarettes currently but of cigars in the past (SCtExCigar).

METHOD

A multicenter epidemiological study enrolling 4,035 subjects aged between 40 and 69 years. One thousand nine hundred sixty-three were non-smokers and 1,146 were current smokers. Among the smokers, 869 were SCt, 37 were SCigar, 97 were SB, 86 were SCigarExCt and 57 were SCtExCigar. We analyzed sociodemographic characteristics, smoking and the prevalence of respiratory symptoms and COPD.

RESULTS

Cigar smokers were usually men, of lower socioeconomic status (p < 0.001) and older than cigarette smokers (p < 0.001), but CO concentrations in expired air were lower in the SCigar group than in the SCt group (5 ppm vs 15.7; p < 0.001). Informants who believed their smoking was not detrimental to their health or to that of second-hand smokers made up 86.5% of the SCigar group and 79.1% of the SCigarExCt group. COPD was diagnosed in 13.2% of the SCt group, in 24.7% of the SB group, and in 12.8% of the SCigarExCt group, in comparison with 4% of the non-smokers (p < 0.001 for all comparisons).

CONCLUSIONS

SCigar are mainly older men with lower educational levels. Their concentrations of CO in expired air are low and they have little awareness of the health risks posed by their habit. SCigar who were once smokers of cigarettes have a higher prevalence of respiratory symptoms and COPD than non-smokers and the same prevalence of COPD as SCt.

Safety of formoterol by Turbuhaler as reliever medication compared with terbutaline in moderate asthma

The present study compared the safety of 4.5 microg formoterol with 0.5 mg terbutaline, both by Turbuhaler and used as needed, in addition to regular formoterol in moderate asthma. In this double-blind parallel-group study, 357 patients taking a moderate-to-high dose of inhaled corticosteroids and additional terbutaline (2-5 inhalations x day(-1) during run-in) were randomised to either formoterol or terbutaline as needed in addition to formoterol 9 microg b.i.d. over 12 weeks. Adverse events, serum potassium levels, electrocardiogram, vital signs and lung function were assessed monthly; peak expiratory flow and severe asthma exacerbations were recorded daily. Patients used 2.16 (range 0.0-6.3) formoterol and 2.34 (range 0.1-7.5) terbutaline relief inhalations x day(-1). No clinically significant differences in safety variables were found between treatments. Statistically greater increases in cardiac frequency (2.6 beats x min(-1), p=0.03) were found on terbutaline. There were 44 and 52 severe asthma exacerbations with formoterol and terbutaline, respectively, with no significant difference in time to first exacerbation. There was also no difference between treatments for other efficacy measures (peak expiratory flow, forced expiratory volume in one second and morning/evening symptom scores). Formoterol 4.5 microg as needed was at least as safe, well tolerated and effective as terbutaline 0.5 mg in stable patients (requiring up to 6 relief inhalations x day(-1)) taking formoterol plus inhaled corticosteroids regularly over 12 weeks.

Inspiratory neural drive response to hypoxia adequately estimates peripheral chemosensitivity in OSAHS patients

The aim of the present study was to examine the relationships between the responses to progressive isocapnic hypoxia and hypoxic withdrawal test in patients with obstructive sleep apnoea-hypopnoea syndrome (OSAHS) and to analyse the determinants of carotid body sensitivity in OSAHS. Nineteen consecutive OSAHS patients and 13 healthy subjects were selected. Ventilatory (delta V'I/Sa,O2/BSA) and inspiratory neural drive (delta P0.1/Sa,O2) responses to progressive isocapnic hypoxia were determined. Peripheral chemosensitivity was evaluated by the hypoxic withdrawal test, which measures the decrease in ventilation caused by two breaths of 100% oxygen (%delta V'I). Withdrawal response and ventilatory and inspiratory neural drive responses to hypoxia were lower in OSAHS patients than in control subjects. In patients with OSAHS, %delta V'I correlated significantly with delta V'I/Sa,O2/BSA and with delta P0.1/Sa,O2. On stepwise multiple linear regression analysis, a strong correlation between %delta V'I and delta P0.1/Sa,O2 was found. Moreover, %delta V'I, delta V'I/Sa,O2/BSA and delta P0.1/Sa,O2 were significantly correlated with minimum arterial oxygen saturation and with arousal index. Obstructive sleep apnoea-hypopnoea syndrome patients have a strong relationship between peripheral chemosensitivity and respiratory response to hypoxia, suggesting that hypoxic stimulation of central chemoreceptors is minimally relevant in obstructive sleep apnoea-hypopnoea syndrome. Moreover, sensitivity of the carotid body in patients with obstructive sleep apnoea-hypopnoea syndrome is related to sleep disruption and to nocturnal hypoxia.

Interpretation of quality of life scores from the St George's Respiratory Questionnaire

The aim of the study was to obtain the general population norms for the St. George's Respiratory Questionnaire (SGRQ), a specific questionnaire for respiratory diseases. The IBERPOC project was a cross-sectional study of representative samples of the general population aged between 40-69 yrs. The study sample was composed of 862 individuals. All participants considered as "probable cases" of chronic obstructive pulmonary disease (COPD) (n=460) were eligible to complete the SGRQ and among the rest of the nonprobable COPD participants (n=3,571), 10 individuals from each defined age and sex group were eligible (n=402). Weights were applied to restore general population representativity of the sample. Mean forced expiratory volume in one second (FEV1) predicted was 89.4% (SD=16.5%; range: 16-131%). Chronbach's alpha coefficients were >0.7 in the symptoms, activity and impact scales, and >0.9 in the overall scale. Symptom scale score was significantly higher among males (11.6 versus 7.8; p<0.01) and activity scale score was significantly higher among females (12.2 versus 14.6; p=0.04). In a multiple linear regression model, respiratory diseases (asthma and COPD) and FEV1 % over pred showed the strongest association with the SGRQ total score. Smoking, sex, age and education were independently associated with the total SGRQ score. These results indicate that individuals from the general population presented some of the problems that are important when measuring health-related quality of life in respiratory patients, and provide St George's Respiratory Questionnaire norms, a useful method for interpreting the St George's Respiratory Questionnaire score in a given patient or study samples.

Reduction of lung distensibility in acromegaly after suppression of growth hormone hypersecretion

Whether the growth of the lungs in acromegaly is due to alveolar hypertrophy or alveolar hyperplasia is a subject of debate. To discriminate these hypotheses, we compared pulmonary distensibility and diffusing capacity among 11 patients with active acromegaly and 11 matched control subjects, evaluating the response of pulmonary distensibility and diffusing capacity to suppression of growth hormone (GH) hypersecretion. We performed lineal and exponential analyses of quasistatic pressure-volume curves. Patients with active acromegaly had a greater TLC, lung compliance, and shape constant, K, than did normal subjects. We found no significant differences between the study groups in carbon monoxide diffusing capacity or diffusing capacity per unit of alveolar volume. After treatment, patients with inactive acromegaly showed a reduced TLC (6.95 +/- 1.40 [mean +/- SD] L versus 6.35 +/- 1.23 L), reduced lung compliance (3.61 +/- 0.90 L/kPa versus 2.36 +/- 0.79 L/ kPa), reduced K coefficient (2.62 +/- 0.65 kPa(-)(1) versus 1.35 +/- 0.40 kPa(-)(1)), and increased maximal recoil pressure (1.74 +/- 0.38 kPa versus 2.28 +/- 0.25 kPa). We conclude that the increased lung distensibility with normal diffusion capacity demonstrated in patients with active acromegaly, which was partly reversible after suppression of GH hypersecretion, suggests that lung growth in acromegaly may result from an increase in alveolar size.

Smoking characteristics: differences in attitudes and dependence between healthy smokers and smokers with COPD

OBJECTIVE

To ascertain the differences in smoking characteristics between a group of smokers with COPD and another group of healthy smokers, both of which were identified in a population-based epidemiologic study.

DESIGN AND PARTICIPANTS

This is an epidemiologic, multicenter, population-based study conducted in seven areas of SPAIN: A total of 4,035 individuals, men and women aged 40 to 69 years, who were selected randomly from a target population of 236,412 subjects, participated in the study.

INTERVENTIONS

Eligible subjects answered the European Commission for Steel and Coal questionnaire. Spirometry was performed followed by a bronchodilator test when bronchial obstruction was present. The Fagerström questionnaire was used for study of the degree of physical nicotine dependence, and the Prochazka model was followed for analysis of the smoking cessation phase.

RESULTS

Of 1,023 active smokers, 153 (15%) met the criteria for COPD. Smokers with COPD were more frequently men (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.21 to 3.95), were > or = 46 years of age (OR, 1.97; 95% CI, 1.18 to 3.31), had a lower educational level (OR, 1.96; 95% CI, 1.23 to 3.14), and had smoked > 30 pack-years (OR, 3.70; 95% CI, 2.42 to 5.65). Smokers with COPD showed a higher dependence on nicotine than healthy smokers (mean [+/- SD] Fagerström test score, 4.77 +/- 2.45 vs 3.15 +/- 2.38, respectively; p < 0.001) and higher concentrations of CO in exhaled air (mean concentration, 19.7 +/- 16.3 vs 15.4 +/- 12.1 ppm, respectively; p < 0.0001). Thirty-four percent of smokers with COPD and 38.5% of smokers without COPD had never tried to stop smoking.

CONCLUSIONS

Smokers with COPD have higher tobacco consumption, higher dependence on nicotine, and higher concentrations of CO in exhaled air, suggesting a different pattern of cigarette smoking. Cases of COPD among smokers predominate in men and in individuals with lower educational levels. A significant proportion of smokers have never tried to stop smoking; thus, advice on cessation should be reinforced in both groups of smokers.

Geographic variations in prevalence and underdiagnosis of COPD: results of the IBERPOC multicentre epidemiological study

OBJECTIVES

To ascertain the prevalence, diagnostic level, and treatment of COPD in Spain through a multicenter study comprising seven different geographic areas.

DESIGN AND PARTICIPANTS

This is an epidemiologic, multicenter, population-based study conducted in seven areas of Spain. A total of 4,035 men and women (age range, 40 to 69 years) who were randomly selected from a target population of 236,412 subjects participated in the study.

INTERVENTIONS

Eligible subjects answered the European Commission for Steel and Coal questionnaire. Spirometry was performed, followed by a bronchodilator test when bronchial obstruction was present.

RESULTS

The prevalence of COPD was 9.1% (95% confidence interval [CI], 8.1 to 10.2%), 15% in smokers (95% CI, 12.8 to 17.1%), 12.8% in ex-smokers (95% CI, 10.7 to 14.8%), and 4.1% in nonsmokers (95% CI, 3.3 to 5.1%). The prevalence in men was 14.3% (95% CI, 12.8 to 15. 9%) and 3.9% in women (95% CI, 3.1 to 4.8%). Marked differences were observed between sexes in smoking; the percentage of nonsmokers was 23% in men and 76.3% in women (p<0.0001). The prevalence of COPD varied among the areas, ranging from 4.9% (95% CI, 3.2 to 7.0%) in the area of the lowest prevalence to 18% (95% CI, 14.8 to 21.2%) in the area of the highest. There was no previous diagnosis of COPD in 78.2% of cases (284 of 363). Only 49.3% of patients with severe COPD, 11.8% of patients with moderate COPD, and 10% of patients with mild COPD were receiving some kind of treatment for COPD. Multivariate analysis showed that individuals had a higher probability of having received a previous diagnosis of COPD if they lived in urban areas, were of male gender, were > 60 years old, had higher educational levels, had > 15 pack-year smoking history, or had symptoms of chronic bronchitis.

CONCLUSIONS

COPD is a very frequent disease in Spain, and presents significant geographic variations and a very low level of previous diagnosis and treatment, even in the most advanced cases.

Changing ventilator: An option to take into account in the treatment of persistent vomiting during nasal ventilation

Problems related with nasal intermittent positive pressure ventilation (NIPPV) are nasal and mouth dryness, soreness on the bridge of the nose, eye irritation and epistaxis. Gastrointestinal distention due to air swallowing has been reported in half of the patients. Acceleration of digestive function with drugs or reduction of the volume delivered to alleviate gastric distension are considered as the conventional treatment. It is also possible that the problem disappears spontaneously after a few weeks of NIPPV. We present a patient in whom conventional treatment was unsuccessful. When we changed to a different ventilator, symptoms disappeared, and the new one was very well tolerated. In our experience, changing ventilators should be included in the management of gastrointestinal distension due to NIPPV, especially if conventional procedures, such as drugs or gas flow modifications, fail.

[Prevalence of and attitudes towards smoking in a population over 40 years of age]

OBJECTIVES

Smoking is the main cause of preventable death in developed countries. One of the most relevant health care interventions is convincing smokers to quit. To achieve that end, it is important to know, in addition to the prevalence of smoking, the degree of physical addiction to nicotine and smokers' attitudes toward tobacco.

MATERIAL AND METHODS

This study collects results from a Spanish national epidemiological study (the IBERPOC study) related to smoking addiction, smokers' degree of addiction to nicotine and smokers attitudes toward their habits. The data has been obtained by surveying 4,035 individuals selected randomly from census data in seven different parts of the country. Information was obtained from questionnaires and CO in expired air was measured.

RESULTS

One thousand fifty-nine respondents were smokers (26%) and 968 were ex-smokers (24%). Female smokers were younger (47 versus 51 years old) and had started smoking later (at age 22 versus 17 years), smoked fewer cigarettes per day (15 versus 21) and had lower concentrations of CO in expired air (13.4 versus 17 ppm) (p < 0.001 for all comparisons). Six hundred fifty-nine smokers (62.2%) had tried to quit at least once. The most important reasons given for trying to quit were related to improving health.

CONCLUSIONS

The 26% of the surveyed population smoked. Women generally started later, smoked fewer cigarettes and were less physically addicted to nicotine. Most smokers had tried at least once to quit, particularly if motivated to improve health. These results should be considered when proposing strategies for smoking cessation.

Sleep apnea and hypertension

STUDY OBJECTIVES

To examine the central inspiratory drive response to hypoxia in patients with obstructive sleep apnea (OSA), according to their circadian BP profile, and in healthy control subjects. Another objective was to evaluate the relationships among sleep architecture, hypoxic sensitivity, urinary catecholamine excretion, and BP in OSA patients.

PATIENTS AND INTERVENTIONS

Polysomnography, 24-h ambulatory BP recording, and urinary excretion of catecholamines were simultaneously examined in 24 consecutive OSA patients and 11 healthy subjects. OSA patients were categorized as being normotensive (type 1), having BP elevation only during sleep (type 2), and as being hypertensive with elevated BP at all times (type 3). The response of mouth occlusion pressure at 0.1 s after onset (P(0.1)) to progressive isocapnic hypoxic stimulation was measured.

RESULTS

There was a significant difference in the P(0.1) response to hypoxia among control subjects ([mean +/- SD] 0.353 +/- 0.129 cm H(2)O/%) and type 1 (0.228 +/- 0.062 cm H(2)O/%), type 2 (0. 345 +/- 0.106 cm H(2)O/%), and type 3 (0.508 +/- 0.118 cm H(2)O/%) OSA patients. In OSA patients, chemosensitivity was related to the apnea-hypopnea index and to the nocturnal excretion of epinephrine. Significant relationships between the nocturnal excretion of epinephrine and BP were noted. On multiple linear regression analysis, the P(0.1) response to hypoxia was the only variable significantly related to diurnal (r(2) = 0.364; p = 0.005) and nocturnal mean BP (r(2) = 0.461; p = 0.002).

CONCLUSION

The findings of the present study suggest a possible mediating role of the peripheral chemosensitivity in the association between sleep apnea and hypertension.

[The internal consistency and content validity of the Spanish version of the Asthma Autonomy Questionnaire]

The Asthma Autonomy Questionnaire (AAQ) was designed to evaluate asthmatics' desire to learn about their disease and to make decisions. The AAQ consists of 26 items distributed in two scales: Preferences in the Search for Information (PSI, 8 items) and Preferences in Decision Making (PDM, 6 general items and 12 related to 3 scenarios depicting asthma in stable phase, during mild exacerbation and during severe exacerbation). The aim of this study was to analyze the internal consistency (Cronbach's-coefficient) and content validity (factorial analysis of principal components) of the AAQ. After translation and back translation, the Spanish version of the AAQ was administered to 115 adult asthmatics of both sexes and differing levels of severity. The alpha coefficients for the two scales and 3 scenarios ranged from 0.42 (PSI) to 0.73 (stable phase scenario); only for the stable-phase scenario were values high or statistically acceptable. Factorial analysis reproduced the content of the scales only approximately, with some items proving to relate to factors that were different from the scale they originally belonged to. These results indicate that, in its current formulation, the AAQ presents important measurement problems and revision is advisable.

[Information seeking and decision making in asthmatic patients]

Patient cooperation in controlling asthma is a key element for achieving the most efficient therapy possible according to current guidelines. Cooperation requires that the patient be adequately informed about his disease and able to make certain decisions. The aim of this study was to analyze whether patients really desire information about asthma and to what point they are disposed to cooperate actively in managing their disease. Ninety-five adult asthmatics with different levels of severity of disease were studied in stable condition. All responded to the Spanish version of the questionnaire on autonomy in asthma, an instrument with a scoring range of 0 to 100 and 26 items grouped in two subscales: preferences in the search for information (PSI) and preferences in decision making (PDM). The second subscale was based on three scenarios describing stable asthma, slight exacerbation and severe exacerbation. The results obtained indicate that although patients are greatly interested in receiving information (PSI scores of 86.4 +/- 8.7) they express substantially less desire to make decisions (PDM 45 +/- 10.2) (p < 0.01). Attitudes did not change in relation to education, number of exacerbations during the last year, duration of disease or severity as assessed by the patient. Only patient age (with older patients scoring higher on PSI) and presence of severe asthma (according to consensus guidelines) increased the desire for information (but not the preference for decision making). These data indicate the need to implement educational programs about asthma, components of which promote effective desire for self-management.

[Epidemiological study of chronic obstructive pulmonary disease in Spain (IBERPOC): prevalence of chronic respiratory symptoms and airflow limitation]

The prevalence of chronic respiratory symptoms and chronic airflow limitation (CAFL) was determined in a multicentric epidemiological study carried out in seven different areas of Spain. Based on a target population of 236,412 persons, a random census sample of 4,035 individuals between 40 and 69 years of age was chosen. Subjects answered several questionnaires and performed spirometric tests followed by a bronchodilation test if bronchial obstruction was detected. Respiratory symptoms were reported by 48% of the population (95% CI: 46.4-49.5%) with greater frequency of symptoms among men than women (55.2% versus 41%, p < 0.001). The following levels of prevalence of chronic symptoms were found: cough, 13.5% (95% CI: 12.5-14.6%); expectoration, 10.7% (95% CI: 9.7-11.6%); dyspnea after one flight of stairs, 10.4% (95% CI: 9.5-11.4%); and wheezing, 40.2% (95% CI: 38.7-41.7%). The prevalence of chronic bronchitis (CB) was 4.8% (95% CI: 4.1-5.4%) and was more frequent among men than among women (8.3% and 1.4%, respectively; p < 0.001). Asthma had been diagnosed previously in 4.9% (95% CI: 4.2-5.5%), more often in women than in men (5.8% and 3.8%, respectively; p < 0.003). CAFL was found in 10.6% (95% CI: 9.6-11.5%), 15.8% in men and 5.5% in women (p < 0.001). All respiratory symptoms except asthma were more frequent among smokers than among ex-smokers, and in turn were more common among ex-smokers than non-smokers. The frequency of symptoms increased in accordance with accumulated smoking. The prevalence of CB and CAFL was vastly different from one region to another. Multivariate analysis showed that factors associated independently with the appearance of CB were smoking, age over 60 years, male sex and having worked in industry. In conclusion, respiratory symptoms, including CB and CAFL, are common in the Spanish population. Smoking and amount of smoking are directly related to the frequency of such symptoms. Substantial differences were found in the prevalence of CB and CAFL among the regions where the study was performed.

[Epidemiological study of chronic obstructive pulmonary disease in Spain (IBERPOC): recruitment and field work]

Chronic obstructive pulmonary disease (COPD) is a large-scale social and health problem. Because prevalence studies have been performed only in certain areas of Spain, the Spanish Society of Pneumology and Chest Surgery initiated the IBERPOC study with the aim of determining the prevalence of COPD in several parts of the country. IBERPOC is a multicenter, population-based epidemiological study in which subjects have been selected randomly. Seven full-time pneumologists work full-time in seven different areas of Spain. A study of this nature involves a series of difficulties that should be taken into account at the time of planning studies of a similar nature. After 5,827 attempts to reach subjects, a total of 4,967 useful contacts were made, to provide 97.3% of the 5,104 contacts expected. Of those 4,967 useful contacts, 4,035 subjects completed interviews. Among the 932 refusals, 882 (94.6%) agreed to answer a short telephone questionnaire. The field work took 13 months to complete, 30% more time than had been anticipated. The rates at which subjects could not be traced differed from one zone to another, ranging between 5% and 30%; higher rates were attributable to the absence of telephone data in the corresponding census report. In one zone, the dispersion of the census population over a very large area supposed greater difficulty and delay in carrying out the study. In conclusion, the rate of participation and the time required for recruitment can be considered satisfactory. The performance of field work by trained, full-time pneumologists has been essential to the development and quality of the study. Similar epidemiological studies should consider problems derived from the lack of adequate census data, as well as to avoid defining areas of extreme population dispersion in order to facilitate field work.

Long-term within-subject variability of inspiratory neural drive response to hypoxia

STUDY OBJECTIVE

We analyze the within-subject variation of mouth occlusion pressure (P0.1) response to progressive isocapnic hypoxic stimulation over long time periods in normal subjects.

PATIENTS AND INTERVENTIONS

We studied 21 healthy subjects (14 male and 7 female; aged 40+/-12 yrs) (mean+/-SD). Lung volumes, basal P0.1, and P0.1 response to hypoxia were measured on two separate occasions 2 months apart, under similar ambient and clinical conditions.

RESULTS

There was no significant change in clinical condition, FVC, FEV1, arterial oxygenation saturation, end-tidal and mixed venous PCO2 levels, or P0.1 between the two visits. The mean P0.1 responses to hypoxia in the two explorations were 0.032+/-0.022 and 0.034+/-0.022 kPa/%, respectively. There was a moderate intrasubject variability of P0.1 response to hypoxia, with a coefficient of reproducibility of 0.01 kPa/%. Power calculations to establish the optimal sample size required for hypoxic stimulation are presented.

CONCLUSION

Long term within-subject variability of P0.1 response to hypoxia is moderate. This intrinsic variability needs to be emphasized when interpreting the effects of experimental interventions on hypoxic sensitivity.

Comparison of helium dilution and plethysmographic lung volumes in pregnant women

The multibreath helium equilibration method is the technique recommended for routine measurement of static lung volumes in normal subjects. However, pregnancy could be an exception to this general rule, due to airway closure during the second half of gestation. The aim of this study was to compare the measurements of lung volumes by plethysmography and helium dilution during pregnancy. Twenty three healthy women were studied at 12, 24 and 36 weeks of pregnancy, and 4 months postpartum. Total lung capacity (TLC), functional residual capacity (FRC) and residual volume (RV) were measured by multibreath helium equilibration (TLCHe, FRCHe and RVHe) and by plethysmography (TLCbox, FRCbox and RVbox). Only at 36 weeks were there differences between the two methods. RVbox was significantly larger than RVHe (1.01+/-0.18 vs 0.77+/-0.21 L; p<0.001). FRCbox was larger than FRCHe (1.95+/-0.32 vs 1.60+/-0.32 L; p<0.001) and TLCbox was larger than TLCHe (4.83+/-0.52 vs 4.45+/-0.51 L; p<0.05). The 95% limits of agreement for differences between lung volumes measured by the two techniques (helium dilution - plethysmography) at 36 weeks were: -0.42 to -0.06 L for RV; -0.54 to -0.17 L for FRC; and -0.66 to -0.11 L for TLC. We conclude that using the multibreath helium equilibration method to measure lung volumes in at-term pregnant women results in underestimation of functional residual capacity and total lung capacity.

Thoracic pain and abnormal chest radiograph

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Regulation of breathing and perception of dyspnea in healthy pregnant women

STUDY OBJECTIVE

To examine if the perception of dyspnea during normal pregnancy may be related to an inappropriate ventilatory response to the increased metabolic rate, due to a higher chemosensitivity.

PATIENTS AND INTERVENTIONS

At weeks 12, 24, and 36 of gestation and 4 months after delivery, 11 healthy pregnant women with dyspnea and 12 asymptomatic pregnant women were studied. Progesterone plasma levels, lung volumes, diffusion capacity, maximal respiratory pressures, rest oxygen uptake, breathing pattern, and mouth occlusion pressure (P0.1) were measured. Progressive isocapnic hypoxic stimulation and progressive hyperoxic hypercapnic stimulation were performed.

RESULTS

Oxygen ventilation equivalent during pregnancy was significantly higher for the dyspneic group than for nondyspneic pregnant women. Dyspneic patients exhibited greater minute ventilation, tidal volume, and P0.1 than the nondyspneic group. The mean values of ventilatory and P0.1 slopes to hypoxia and CO2 during pregnancy were significantly greater in the patients with dyspnea than in asymptomatic subjects. These changes were not due to differences in progesterone plasma levels. A significant relation among the Borg score, inspiratory drive, and chemosensitivity was found.

CONCLUSIONS

In some pregnant women, a higher sensitivity to CO2 and hypoxia may induce excessive ventilation to metabolic demand, which would contribute to dyspnea.

[An early detection program for respiratory insufficiency in Duchenne's disease: the preliminary results]

Noninvasive mechanical ventilation through a nasal mask is a recently introduced therapeutic tool that represents a noteworthy advance in home treatment for patients with respiratory insufficiency secondary to ventilatory pump failure. We present the preliminary results of a program for early detection of respiratory insufficiency in patients with Duchenne's disease. Sixteen patients (mean age 15.8 years) with this disease were evaluated between January 1994 and January 1995. Mean lung function parameters were FVC 1,440 ml (46.7%), PO2 87.3 mmHg, PCO2 40.8 mmHg, PIM 40.1 cmH2O (30.6%), and PEM 41 cmH2O (25%). Two patients had abnormal pulse oximetry readings at night and abnormal gasometric readings during the day and were started on mechanical ventilation through nasal masks. These 2 patients were older, more hypoxemic and hypercapnic, had lower FVC values and showed greater deterioration of inspiratory and expiratory muscle pressures.

[Ambulatory oxygen therapy via a transtracheal catheter]

Oxygen therapy by transtracheal catheter (TTC), as described by Heimlich in 1982, was originally conceived to conserve oxygen but later proved to be truly useful as a treatment for chronic respiratory insufficiency, although the technique is little used in Spain. We conducted a one-year long prospective study of 10 patients with chronic respiratory insufficiency in whom a TTC was placed for ambulatory oxygen therapy. Complications appearing were bloody expectoration (100%), granulomas at the site of incision (20%) and accidental extubation (10%). The index of acceptance among our patients was 9%. The oxygen savings achieved amounted to 46%. The number of hospitalized days before and after insertion of the catheter amounted to 28 and 3, respectively (p < 0.001). PCO2 levels were 62 +/- 14 at baseline, 51.9 +/- 8.8 (p < 0.1) after one week, and 52.9 +/- 10 (NS) after one year. The hematocrit was 45.6 +/- 10.22 before TTC placement and 43.4 +/- 3.02 (NS) after one year. Changes in PO2, FVC and FEV1 were not statistically significant. No problems derived from TTC or liquid oxygen management.

Value of the peak expiratory flow in bronchodynamic tests

OBJECTIVE

To determine the accuracy of the peak expiratory flow (PEF) as an alternative parameter to the forced expiratory volume at first second (FEV1) in the bronchodynamic tests.

METHODOLOGY

We studied 84 patients, 53 males and 31 females, with average age 46 +/- 13 years, as clinic suspects of bronchial asthma. PEF was determined with a "mini-Wright peak flow meter" and a spirometry was obtained. Based on the results, 44 subjects were classified under group 1 (FEV1/FVC < 70% and FEV1 < 80% of theoretic value) and subjected to a bronchodilator test. While in group 2 subjects (normal spirometry), a methacholine challenge was performed. During each procedure, PEF readings were obtained before FEV1 determination. The usefulness of the PEF for the diagnosis of reversibility or bronchial obstruction with respect to the FEV1 was assessed in both groups.

RESULTS

In the bronchodilator tests, a cut-off point was found for the increase in the PEF > 18%, which showed a sensitivity of 85%, specificity of 79%, positive predictive value of 77% and negative predictive value of 86%, with respect to an increase in the FEV1 > 15%. In the methacholine challenge, a decrease in the PEF > 12% only achieved a sensitivity of 74% and specificity of 71%.

CONCLUSION

Peak expiratory flow may be an useful parameter in bronchodilator tests. However, it should not be used in methacholine challenge.

[Portable oxygen therapy in the Madrid area]

Portable oxygen therapy using liquid oxygen has been available in the Madrid area since 1992 as part of a government program. The prescription of liquid oxygen theoretically requires the careful selection of patients who will benefit from a portable source of oxygen, as well as the performance of a series of treadmill tests with and without supplemental oxygen in order to assess the benefit derived from this expensive means of delivering therapy. As no studies had been done of whether these criteria for prescribing liquid oxygen were being met, we conducted telephone interviews with patients residing in the Madrid area who had portable oxygen sources at their disposal. Of a total of 190 patients, whose names were provided by oxygen supply companies, 145 could be evaluated. Liquid oxygen was not being used by 17%. Stress tests had not been performed before prescription of liquid oxygen in 65%. In conclusion, it can be suspected that a high percentage of patients receive liquid oxygen who do not meet the criteria for prescription and who have not performed the recommended tests, and that compliance is low.