Percentage Of Peak Expiratory Flow Research Articles

Effect of budesonide/glycopyrrolate/formoterol fumarate metered dose inhaler combined with nasal high-flow nasal cannula on elderly patients with COPD and respiratory failure.

To explore the clinical effect of budesonide/glycopyrrolate/formoterol fumarate metered dose inhaler (BGF MDI) combined with high-flow nasal cannula (HFNC) in the treatment of elderly patients with chronic obstructive pulmonary disease (COPD) and respiratory failure. The clinical records of 94 elderly patients with COPD and respiratory failure who were treated in Yongkang First People's Hospital from February 2022 to January 2023 were retrospectively selected. Among them, 46 patients received HFNC alone (Control-group) and 48 patients received HFNC combined with BGF MDI (Study-group). The treatment effect, arterial blood gas status, pulmonary function, and acute physiology and chronic health evaluation (APACHE) II score before and after treatment were analyzed in both groups. The total efficacy of treatment in the Study-group (95.8%) was higher than that in the Control-group (78.3%) (P<0.05). After treatment, the partial pressure of arterial carbon dioxide (PaCO2), residual volume, and APACHE II scores in the two groups decreased compared to those before treatment, with the Study-group lower overall. However, arterial oxygen saturation (SaO2), oxygen partial pressure (PaO2), the percentage of peak expiratory flow (PEF), and forced expiratory volume in one second (FEV1) as percent of predicted (%FEV1) were higher than before treatment, and higher in the Study-group (P<0.05). Compared with HFNC alone, BGF MDI combined with HFNC can effectively regulate the arterial blood gas status of elderly patients with COPD and respiratory failure, restore pulmonary function, and improve the overall treatment effect.

The Subglottic Stenosis 6 Questionnaire: A Novel Quality-of-Life Survey Validated to Predict Need for Intervention in Patients With Idiopathic Subglottic Stenosis

Idiopathic subglottic stenosis (iSGS) is a recurrent, chronic disease defined by fibroinflammatory narrowing of the subglottic airway. A key challenge in treatment is monitoring disease progression, which may be debilitating and unpredictable in its timing. Can the Subglottic Stenosis 6 (SGS-6) questionnaire be validated as a novel quality-of-life (QOL) instrument to monitor breathing, disease progression, and disease severity proactively in patients with iSGS? Panel data from 51 patients with iSGS were collected from January 2012 through June 2022, representing 1,684 patient encounters including routine office visits and treatment encounters. Subjective QOL scores (including the novel SGS-6 and established RAND-36 and EuroQol Five Dimensions [EQ-5D] Visual Analog Scale) and objective pulmonary function test (PFT) results were collected at each visit. Subjective SGS-6 QOL scores were repeated within 1week of initial reporting. Panel regression analyses were performed to assess the relationship between SGS-6 scores, PFT results, and a patient's need for intervention. Minimal clinically important differences (MCIDs) for SGS-6 and peak expiratory flow percentage (PEF%) were assessed using receiver operating characteristic (ROC) curve analysis and a patient's need for intervention as the external anchor. Each one-point increase in SGS-6 score (of a maximum of 27) was associated with a 3.26%decrease in PEF%, a 1.93-point decrease in RAND-36 Physical Health composite score, a 1.27-point decrease in RAND-36 Mental Health composite score, and a 0.88-point decrease in EQ-5D Visual Analog Scale score. The intracorrelation coefficient for the SGS-6 composite score is 0.838 (95%CI, 0.770-0.888). Compared with patient baselines, SGS-6 scores were 4.66 points greater at the time of intervention with an MCID of 2.25 from a patient's baseline. The area under the ROC curve for SGS-6 and a patient's intervention point was 0.81. iSGS disease severity can be modeled using the SGS-6 questionnaire, offering physicians and patients a potentially new method of tracking disease progression and need for intervention remotely.

Efficacy of omalizumab in the treatment of eosinophilic granulomatous polyangiitis with asthma as the first symptom

Objective: To investigate the efficacy, and safety of omalizumab in the treatment of eosinophilic granulomatous with polyangiitis (EGPA) with asthma as the first symptom. Method: The clinical characteristics of 22 EGPA patients with asthma as the first symptom treated with omalizumab in the First Affiliated Hospital of Guangzhou Medical University from March 2018 to December 2020 were retrospectively analyzed. The asthma control test (ACT) score, the frequency of asthma exacerbation (AE), the Birmingham Vasculitis Activity Score (BVAS), the variation rate of peak expiratory flow (PEF), the percentage of PEF to predicted value of PEF (PEFpred%), the percentage of forced expiratory volume in first second (FEV1) to predicted value of FEV1 (FEV1pred%), the dosage of oral corticosteroid (OCS) and other clinical data [M(Q1, Q3)] were collected before and after treatment, to observe the efficacy and adverse reactions of omalizumab. Results: There were 22 subjects recruited in this study. The median age was 42 (22-70) years. Eleven of the patients were males. After treated with omalizumab for 4 months, there were 68.2%(15/21) of patients who responded to the treatment. In the response group (n=15), the patients' ACT score increased from 19.0 (16.5, 21.0) to 23.0 (21.5, 24.0) (P=0.001). The frequency of AE decreased from 0.7 (0.3, 1.0) to 0 (0, 0.7) per four mouths (P<0.001). The BVAS decreased from 4.0 (2.0, 6.0) to 2.0 (2.0, 4.0) (P=0.007). The variation rate of PEF decreased from 18.8% (14.0%, 27.7%) to 9.2% (6.8%, 11.9%) (P=0.007). The PEFpred% increased from 80.8% (73.5%, 90.7%) to 100.5% (79.4%, 114.0%) (P=0.005). The maintenance dosage of OCS reduced from 15.0 (10.0, 20.0) mg/d to 8.8 (5.0, 10.0) mg/d (P=0.005). The level of baseline eosinophil in peripheral blood of patients in non-response group was higher than that in response group [11.4% (9.2%, 22.6%) vs 3.4% (1.1%, 6.5%), P<0.05]. A total of 190 injections were performed in 22 patients, and only 4 patients (2.1%) had adverse reactions after a single injection of omalizumab, such as dizziness, swelling of injection site and pruritus. The adverse reactions were tolerable. Conclusions: Omalizumab has certain curative effect on EGPA, can reduce asthmatic symptoms and OCS maintenance dosage, and has a good safety profile. The rate of response to the treatment is higher in patients with mild eosinophilic inflammation.

Clinical Effect of Atomized Budesonide and Terbutaline Inhalation for Acute Attack of Pediatric Asthma

The research aimed to explore the clinical effect of atomized budesonide and terbutaline inhalation for acute pediatric asthma. Ninety children with mild or moderate asthma treated in our hospital from January 2019 to December 2019 were selected as study subjects and divided into observation group and control group according using random number table, with 45 patients in each group. On acute attack of asthma, both groups received treatments of fluid rehydration, oxygen inhalation, anti-infection, oral smooth asthma drugs, etc. Both groups were treated with atomized inhalation of budesonide, with the observation group treated with extra atomized inhalation of terbutaline. The therapy lasted for continuous 7 d. The inflammatory factor levels, stress response, lung function and clinical efficacy were compared between the two groups. Forced expiratory volume 1 percentage, peak expiratory flow percentage and forced vital capacity percentage were significantly increased both in control and observation groups (p<0.05). After treatment, both groups showed lower levels of serum nitric oxide and endothelin and higher levels of serum superoxide dismutase than before, with statistically significant differences (p<0.05). There was no significant difference in serum superoxide dismutase, nitric oxide and endothelin levels between the two groups after treatment. Observation group showed no significant differences in the duration of dyspnea, cough and lung rale and hospital stay with control group after treatment (p>0.05). The serum levels of interleukin-6, interleukin-8 and tumor necrosis factor decreased significantly in both groups (p<0.05) with significantly lower levels in observation group than in control group (p<0.05). The total effective rate of observation group was significantly higher than that of control group with significant difference (p<0.05). The treatment of budesonide combined with terbutaline for acute attacks of asthma can significantly improve patients’ lung function, relieve clinical symptoms, reduce inflammation level and ultimately improve the treatment effect, which is worth clinical promotion and application.

The effects of breathing exercises on respiratory functions, functional capacity and quality of life in vehicle spray painters

Background/aims Workers engaged in vehicle spray painting are at a risk of developing respiratory problems because of the solvents in the spray paints. Changes in respiratory functions and functional capacities caused by spray painting can be improved with respiratory exercises. The aim of this study was to examine the effects of respiratory exercises on the respiratory functions, functional capacity and quality of life in vehicle spray painters. Methods A total of 70 volunteers with similar characteristics participated in the study. The groups were divided into two groups randomly (35 study group, 35 control group). Respiratory functions (value of forced expiratory volume percentage in 1 second [FEV1]), forced vital capacity percentage [FVC], FEV1/FVC percentage, peak expiratory flow percentage [PEF (%)] and maximum voluntary ventilation percentage [MVV (%)]), functional capacity (6-Minute Walk Test) and quality of life (Short Form Health Survey [SF-36]) were evaluated. The study group undertook supervised breathing exercises 3 days a week for 6 weeks. The same exercises were given to the control group as a home programme. Home programmes were followed up by telephone calls. Evaluations were performed again after 6 weeks. Results In the study group, FEV1 (%) increased more than in the control group (P&lt;0.05). The increase in PEF (%) was similar in both groups (P&gt;0.05). In the study group, FEV1/FVC (%) and MVV (%) were significantly different before and after the intervention (P&lt;0.05), but there was no difference in the control group (P&gt;0.05). There was a greater increase in the study group than in the control group (P&lt;0.05). 6-Minute Walk Test distance (m) before and after the intervention in both groups were similar (P&gt;0.05). Before and after the intervention, a significant difference was found in the vitality and the social function domains of the SF-36 in the study group. In the comparisons of groups, a significant difference was found in the study group in the role-emotional, social function and bodily pain domains of the SF-36 after the intervention (P&lt;0.05). Conclusions Breathing exercises can be recommended for vehicle spray painters to avoid an increase in respiratory resistance and to improve their quality of life.

Reliability of peak expiratory flow percentage compared to endoscopic grading in subglottic stenosis.

ObjectiveTo determine the reliability of pulmonary function testing compared to endoscopic grading in the assessment of subglottic stenosis.MethodsConsecutively treated patients with subglottic stenosis at a tertiary care specialty hospital from 2009 to 2019 were identified. Two fellowship‐trained laryngologists and two otolaryngologists blinded to clinical history reviewed laryngo tracheoscopic examinations and assessed the degree of stenosis using the Cotton‐Myer grading system (% stenosis). Nine full flow‐volume loops were performed at the time of each exam.ResultsThe endoscopic images of 45 subjects were graded for degree of stenosis and the spirometry data were analyzed. The kappa values for Cotton‐Myer grade overall was 0.37, grade I was −0.103, grade II was 0.052, and grade III was 0.045. The overall intraclass correlation of the physician grading of estimated percent obstruction (% stenosis) was 0.712 (P < .01) whereas the overall intraclass correlation for PEF% was 0.96 (P < .01). Within each Cotton‐Myer grade, the intraclass correlation for % stenosis was 0.45 (P = .02) for grade I, 0.06 (P = .30) for grade II, and 0.16 (P = .03) for grade III. The intraclass correlation for PEF% for grade I was 0.97 (P < .01), grade II was 0.92 (P < .01), and grade III was 0.96 (P < .01).ConclusionCotton‐Myer grading and estimating percent obstruction (% stenosis) for adult subglottic stenosis showed poor reliability as an assessment tool compared to the excellent intraclass correlation seen with pulmonary function tests within each Cotton‐Myer grade subgroup. We recommend pulmonary function testing, specifically PEF% because it is a normalized value, for the assessment and management of subglottic stenosis.Level of evidence4.

Abdominal wall incisional hernia repair improves respiratory function: results after 3\xa0years of follow-up

PurposeHernias severely impact patient quality of life (QoL), and 80% of patients require a surgical operation. Moreover, hernias are responsible for respiratory function alterations. This study aims to investigate the postoperative alterations in respiratory function after open ventral hernia repair in patients with incisional hernia.MethodsPatients operated on at the Policlinico “Paolo Giaccone” at Palermo University Hospital between January 2015 and December 2016 were identified in a prospective database. Fifty-one patients were enrolled in the study. The respiratory outcome measures used were forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio, peak expiratory flow (PEF) and PEF percentage (%PEF). The timepoints at which the parameters listed were assessed were t0, 1 week before the surgical operation; t1, 12 months later; and t2, 3 years later.ResultsThe difference between mean preoperative and postoperative PEF was significant [t0 4.32 (4.03–7.92), t1 6.7 (4.27–8.24) with p = 0.012 and t2 6.5 (4.25–8.21) with p = 0.026]. The %PEF increased from 75% preoperatively to 87% at t1 (p = 0.009) and to 85% at t2 (p = 0.03). No differences were found in the comparison of pre- and postoperative FVC, FEV1 or FEV1/FVC ratio.ConclusionThe improvement in respiratory measures suggests the importance of abdominal wall restoration to recover functional activity of respiratory function.

Respiratory and upper limb function as outcome measures in ambulant and non-ambulant subjects with Duchenne muscular dystrophy: A prospective multicentre study

The field of translational research in Duchenne muscular dystrophy (DMD) has been transformed in the last decade by a number of therapeutic targets, mostly studied in ambulant patients. A paucity of studies focus on measures that capture the non-ambulant stage of the disease, and the transition between the ambulant and non-ambulant phase. In this prospective natural history study, we report the results of a comprehensive assessment of respiratory, upper limb function and upper limb muscle strength in a group of 89 DMD boys followed in 3 European countries, 81 receiving corticosteroids, spanning a wide age range (5–18 years) and functional abilities, from ambulant (n = 60) to non-ambulant (n = 29). Respiratory decline could be detected in the early ambulatory phase using Peak Expiratory Flow percentage predicted (PEF%), despite glucocorticoid use (mean annual decline: 4.08, 95% CI [−7.44,−0.72], p = 0.02 in ambulant; 4.81, 95% CI [−6.79,−2.82], p < 0.001 in non-ambulant). FVC% captured disease progression in non-ambulant DMD subjects, with an annual loss of 5.47% (95% CI [−6.48,−4.45], p < 0.001). Upper limb function measured with the Performance of Upper Limb (PUL 1.2) showed an annual loss of 4.13 points (95% CI [−4.79,3.47], p < 0.001) in the non-ambulant cohort. Measures of upper limb strength (MyoGrip and MyoPinch) showed a continuous decline independent of the ambulatory status, when reported as percentage predicted (grip force −5.51%, 95% CI [−6.54,−4.48], p < 0.001 in ambulant and a slower decline −2.86%; 95% CI −3.29,−2.43, p < 0.001, in non-ambulant; pinch force: −2.66%, 95% CI [−3.82,−1.51], p < 0.001 in ambulant and −2.23%, 95% CI [−2.92,−1.53], p < 0.001 in non-ambulant). Furthermore, we also explored the novel concept of a composite endpoint by combining respiratory, upper limb function and force domains: we were able to identify clear clinical progression in patients in whom an isolated measurement of only one of these domains failed to appreciate the yearly change. Our study contributes to the field of natural history of DMD, linking the ambulant and non-ambulant phases of the disease, and suggests that composite scores should be explored further.

Quality-of-Life Metrics Correlate With Disease Severity in Idiopathic Subglottic Stenosis.

Idiopathic subglottic stenosis (ISGS) can have significant impacts on quality of life (QOL), but it remains unclear how patients' subjective responses correlate with objective measurement of disease severity. Peak expiratory flow percentage (PEF%) has been shown to be an effective measure of disease severity in subglottic stenosis. This study aims to identify the key QOL questions correlated with PEF% and proposes a statistical model for prediction of disease severity. Patients with ISGS presenting to an academic laryngologist were included retrospectively from 2012 to 2016. Peak expiratory flow percentage (age, sex, and height adjusted) was recorded for each visit, along with four validated QOL instruments (European QOL-Five Dimensions; RAND 36-Item Health Survey; Clinical COPD [Chronic Obstructive Pulmonary Disease] Questionnaire; and the Airway, Dyspnea, Voice, and Swallowing Summary Assessment). A stepwise multiple linear regression was used to identify statistically significant independent variables correlated with PEF%, and a model was built with these variables. Thirty-two patients were included, with a total of 271 patient encounters. Overall scores from each of the four QOL instruments were correlated with PEF% values recorded each visit (P < 0.05). Question responses correlating most positively included overall breathlessness, difficulty catching breath, cough within the past week, dyspnea with moderate activity, perception that voice changes are restricting social life, and overall general health (all P < 0.01). A model constructed using six nonoverlapping questions yielded an adjusted R2 of 0.58. Quality of life is correlated to PEF% in ISGS. Using a limited number of QOL questions, clinicians can predict objective worsening or improvement of disease severity, as measured by spirometry. 2b. Laryngoscope, 2017.

Effects of pulmonary function training on the lung function and surgical tolerance of lung cancer patients with obstructive ventilatory defects

Objective To study the effects of pulmonary function training on the lung function and surgical tolerance of lung cancer patients with different degrees of obstructive ventilatory defect. Methods Pulmonary function training was performed with 103 lung cancer patients with obstructive ventilatory defects (26 mild cases, 53 moderate cases, 24 severe cases). The duration of the intensive training was 5-7 days. Vital capacity (VC), vital capacity percentage (VC%), forced vital capacity (FVC), forced vital capacity percentage (FVC%), forced expiratory volume in one second (FEV1), percentage of the forced expiratory volume in one second (FEV1%), maximum voluntary ventilation percentage (MVV%), peak expiratory flow percentage (PEF%), fraction of the forced expiratory volume in one second (FEV1/FVC), and maximum mid-expiratory flow percentage (MMEF%) were measured before and after the training. Any postoperative complications were recorded. Results The average MMEF% improved significantly among the moderate patients after their training. Eventually 19/26 patients (73.08%) in the mild group, 34/53 patients (64.15%) in the moderate group, and 8/24 patients (33.33%) in the severe group met the requirements to undergo lung operations. These were significant differences among the groups. Among those operated on, 27 (44.26%) suffered from postoperative complications, a significantly higher percentage than among the normal controls (20.00%). Conclusion Lung function exercises can improve the operation tolerance of lung cancer patients with obstructive ventilation dysfunction, but the risk of operating is still much higher than for patients with normal ventilation function. Key words: Pulmonary function training; Obstructive ventilatory defects; Lung cancer; Surgical tolerance

The relationship between serum 25 hydroxy vitamin D3 concentrations and lung function, exhaled nitric oxide in children with bronchial asthma

Objective To determine the serum 25 hydroxy vitamin D3[25(OH)D3]levels in children with bronchial asthma and its relationship with lung function, fraction of exhaled nitric oxide(FeNO). Methods Totally 112 children with asthma aged 6 years to 14 years old were selected as the study group, meanwhile 78 healthy children aged 6 years to 14 years old were selected as the control group, serum 25(OH)D3 was determined using the electrochemical luminescence method.Lung function was measured, which included peak expiratory flow(PEF), forced expiratory volume in one second(FEV1), percentage of PEF in predicted value(PEF% pred), percentage of FEV1 in predicted value(FEV1% pred). FeNO of the study group was measured.The relationship between serum 25(OH)D3 and PEF% pred, FEV1% pred, FeNO were all analyzed. Results The proportion of vitamin D deficiency and insufficiency in the study group were higher than those in the control group(χ2=7.78, P<0.01). The values of PEF% pred and FEV1% pred were decreased with the decreasing of the 25(OH)D3 levels(F=28.12, 29.56, P<0.05), FeNO values were increased with the decreasing of the 25(OH)D3 levels (F=15.65, P<0.05). Conclusion Vitamin D deficiency or insufficiency is related to asthma in children.It is associated with the decrease of lung function, and can increase the level of airway inflammation in children with asthma. Key words: Asthma; 25 hydroxy vitamin D3; Lung function; Fraction of exhaled nitric oxide,

206 Clinical Effects of Immunotherapy in Patients with Allergic Disease in the National Institute of Respiratory Diseases

BackgroundPrevious studies have shown that after the treatment with immunotherapy there is a reduction in the number of visits to emergency services for asthma crisis, a significant improvement in pulmonary function tests: forced vital capacity (FVC), forced expiratory volume percentage in 1 second (FEV1%) and in the percentage of peak expiratory flow (PEF%) and the dose and number of drugs. There is also evidence of decreased response to skin tests and IgE levels with immunotherapy specific to Dermatophagoides pteronyssinus (Dpt).MethodsThe objective of this study was to evaluate the clinical effects of immunotherapy in patients with allergic disease treated at the National Institute of Respiratory Diseases in Mexico City, Mexico. There was a random selection in a prospective study of 99 patients with positive skin tests and more than 18 months of treatment with subcutaneous immunotherapy specific to epithelia, pollens from trees, grasses and weeds; at the beginning and the end of the immunotherapy there was an evaluation of the scale of rhinitis symptoms and asthma control; pulmonary function tests were performed as well (spirometry).ResultsAt the initial evaluation, 97% of patients presented moderate to severe persistent rhinitis, 80% of patients with asthma was uncontrolled; after 18 months with specific immunotherapy 80% of patients presented moderate intermittent rhinitis and asthma control was achieved in 85% of the patients. The FEV1 average increased from 78% at the beginning to 89% (P < 0.001). The average bump at the beginning of the specific immunotherapy was 12 cm for Dpt, for trees 10 cm, for weeds 8 cm and for grasses 8 cm; at the end of the SIT the average bump for Dpt was 10 cm, trees 2 cm, weeds 1cm and grass 0 cm (P value < 0.01).ConclusionsThe specific subcutaneous immunotherapy had beneficial clinical effects in patients with allergic disease, with significant improvement in pulmonary function tests and reduced positivity in skin tests, specifically for patients who were sensitive to pollens from trees, weeds and grasses.

The effect of chronic carbon monoxide exposure on hs-CRP, CIM thickness and PEF in furnacemen

Objective: The relationship of atherosclerosis, carotid intima media thickness, high sensitive C-reactive protein and the airway narrowness in patients who were exposed to chronic carbon monoxide was evaluated. Materials and Methods: Forty seven healthy non-smoker male furnacemen who have been working at least ten years, and 48 non-smoker healthy men were enrolled to the study. The body mass index, blood pressure, total cholesterol, triglyceride, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, carotid intima media thickness, carboxyhemoglobin, high sensitive C-reactive protein and peak expiratory flow velocity of both groups were evaluated. Results: Carboxyhemoglobin (p <0.001), high sensitive C-reactive protein (p <0.001) and carotid intima media thickness (p <0.001) levels were found to be higher in furnaceman group. While the carotid intima media thickness (p <0.001), carboxyhemoglobin (p <0.001) and high sensitive C-reactive protein (p <0.001) values were observed significantly higher, the peak expiratory flow percentage was significantly lower in furnaceman group (p <0.001). There was a statistically significant correlation between age and carboxyhemoglobin (p <0.004); carboxyhemoglobin and high sensitive C-reactive protein levels (p <0.001); carboxyhemoglobin level and working years (p <0.001); high sensitive C-reactive protein values and working years (p <0.001); peak expiratory flow percentage and carboxyhemoglobin level (p <0.001), peak expiratory flow percentage and working years (p <0.001), peak expiratory flow percentage and age (p <0.007); high sensitive C-reactive protein levels and exposure year (p <0.001), carotid intima media thickness and exposure year (p = 0.035) in furnaceman group. Conclusion: Chronic carbon monoxide exposure increases high sensitive C-reactive protein and carotid intima media thickness in the course of time and lays the groundwork for atherosclerosis and also decre

Predicting asthma exacerbations: Peak expiratory flow revisited

The ability to predict and prevent future exacerbations has been a consistent focus of asthma research. Although some progress has been made on identifying factors associated with an increased risk of exacerbation at the population and individual levels, no measure or instrument is available for widespread use in the asthma community. In this issue of the Journal, Thamrin et al present a statistical method used to calculate the future exacerbation risk for a patient (as defined by deterioration in percent predicted peak expiratory flow [PEF]) based on the history of fluctuations in lung function (percent predicted PEF). The authors challenge us to reframe our analytic approach to asthma. Frey et al have suggested that a patient with asthma should be thought of as a complex, nonlinear dynamic systems network; such a network exhibits fluctuations over time in physiologic and clinical variables. However, such a system also exhibits memory effects, and although changes can occur over time, the recent past will include most of the pertinent information needed to predict the short-term future risk. Viewingasthma through this framework, it follows that the single best individual parameter to predict the risk of an exacerbation over the next year is the history of an exacerbation in the prior year. The natural history of asthma in any given patient is a summation of personal characteristics (eg, demographics, inflammatory profile, and lungmechanics), genetics, both the physical (exposure to environment [environmental tobacco smoke, pollution, and allergens]) and psychosocial (access to care) environment, and therapy (including adherence). The complex interaction of these factors results in the overall clinical phenotype expressed by a patient, and this helps explain why the recent past is a strong predictor of future events. Modeling asthma as a complex, nonlinear dynamic system also fits with our increasing recognition of the heterogeneity of asthma. Patients with asthma present differently in regard to symptoms, physiologic measures, inflammatory indices, and perception of obstruction; measuring a single parameter at a single point might not

Effects of Aerobic Fitness and Pulmonary Function on Mechanical Ventilatory Constraints During Exercise in Healthy Women

Females with a higher maximal aerobic capacity (Vo2max) have higher ventilatory requirements during exercise relative to their untrained counterparts. The higher ventilatory loads in trained females might make them more susceptible to developing expiratory flow limitation (EFL) during exercise. However, the interrelationship between aerobic fitness, pulmonary function and EFL has not been well characterized in women. PURPOSE: To determine the effect of Vo2max and maximal expiratory flow-volume (MEFV) curve characteristics on EFL in healthy women. METHODS: A progressive stepwise cycle test to exhaustion was completed by 22 healthy females (age=28±5; Vo2max=49±8, range 31-62 ml·kg-1·min-1). A MEFV curve was generated by having subjects perform several expirations from total lung capacity to residual volume at different efforts before and after exercise. Tidal breaths at each exercise stage were superimposed within the MEFV curve by having subjects perform inspiratory capacity maneuvers. The magnitude of EFL was calculated as the percent of the tidal breath that met or exceeded the outer boundary of the MEFV curve. Subjects were partitioned into those with EFL (n=10) and those with no EFL (NEFL; n=12). RESULTS: There was no difference in Vo2max between the EFL group and the NEFL group (47±5 vs. 51±10 ml·kg-1·min-1, respectively, P >0.05). There was no relationship between the degree of EFL and Vo2max (r=0.18, P>0.05). Absolute values were different between the EFL and NEFL groups for: peak expiratory flow (PEF) (6.9±0.9 vs. 8.5±1.0 l·sec-1, P < 0.05), and for forced expiratory flows at 75% of vital capacity (FEF75%) (6.0±0.6 vs. 7.6±0.9 l·sec-1, P<0.05), 50% of vital capacity (FEF50%) (3.5±0.4 vs. 5.6±1.0 l·sec-1, P<0.05) and 25% of vital capacity (FEF25%) (1.8±0.2 vs. 3.0±0.9 l·sec-1, P<0.05). The forced vital capacity was significantly larger in the NEFL group compared to the EFL group (4.4±0.5 vs. 3.8±0.4 l, P<0.05). When expressed as a percentage of PEF, FEF75% was not different between groups (87±7 vs. 90±6%, P>0.05) while FEF50% (52± 8 vs. 66±6%, P<0.05) and FEF25% (26±6 vs. 35±7.39%, P<0.05) were different. CONCLUSION: The degree of EFL experienced by women appears to be more associated with lung size and the characteristics of their MEFV curve rather than aerobic fitness. Funding: BC Lung Association and NSERC

Relationship of the Asthma Control Test with pulmonary function and exhaled nitric oxide

The Asthma Control Test (ACT) is a short, simple, patient-based tool for identifying patients with poorly controlled asthma; however, its value in practice has yet to be demonstrated. To clarify the relationship of ACT scores and clinical parameters, including pulmonary function tests, peak expiratory flow (PEF) indices, and exhaled nitric oxide (eNO) levels. The study included 105 patients with asthma who underwent routine checkups by asthma specialists since September 1, 2006, through January 31, 2007. All patients had been taking inhaled corticosteroids with or without other medications for asthma for at least 3 months. The patients completed the ACT questionnaire and underwent testing for eNO and spirometry. PEF indices, including PEF percentage of predicted value (%PEF), lowest PEF during 1 week expressed as a percentage of the highest PEF (Min%Max PEF), and PEF variability, were also analyzed in patients undergoing PEF monitoring. The ACT scores ranged from 8 to 25 (median, 24), and total control was obtained in 45 patients (42.8%). The PEF indices and eNO values in the total control group were significantly better than those in the less controlled groups. However, the ACT scores were weakly correlated with percentage of predicted forced expiratory volume in 1 second (r = 0.219), %PEF (r = 0.387), Min%Max PEF (r = 0.354), PEF variability (r = -0.351), and eNO values (r = -0.310). Total control of ACT included uncontrolled conditions in physiologic and inflammatory parameters. ACT should be used in combination with pulmonary function tests and/or eNO measurements.

Comparison of Individuals with and Without Specific IgA Antibodies to Chlamydia pneumoniae: Respiratory Morbidity and the Metabolic Syndrome

To determine whether a correlation exists between markers for persistent Chlamydia pneumoniae infection, respiratory morbidity, and the metabolic syndrome. Case-control study. A group of individuals with serologic markers (specific IgA > or = 1/128) suggestive of persistent C pneumoniae infection were compared with a group of control subjects without IgA antibodies (< 1/32). Apoteksgårdens Health Care Center, Kopparberg, Sweden. One hundred case subjects (61 men and 39 women) and 100 control subjects matched for age and gender (mean age, 55 years). Individuals completed a questionnaire on respiratory symptoms and smoking habits. Body mass index (BMI) was calculated, BP, and peak expiratory flow (PEF) were determined. Blood specimens were drawn for determination of high-sensitivity C-reactive protein (hsCRP), blood glucose level, serum lipids, and Chlamydia antibodies. No significant difference was found between case subjects and control subjects regarding myocardial infarctions, stroke, diabetes type II, BP, BMI, hsCRP, blood glucose levels, and serum lipids. Symptoms of both asthma and chronic bronchitis were more common in case subjects, as were symptoms of chronic upper respiratory tract infections (p < 0.005). Case subjects with asthma or chronic bronchitis had more chronic upper respiratory tract disorders (p < 0.05). Symptoms of chronic respiratory tract diseases increased parallel to increasing specific C pneumoniae IgA antibody titers (p < 0.0005). PEF percentage of the predictive value was inversely correlated (p < 0.0005) to IgA antibody titers. The data show that persistent increased levels of C pneumoniae IgA antibodies were associated with pronounced respiratory dysfunction. These data provide additional evidence suggesting that IgA antibodies may be a marker for persistent C pneumoniae infection.

Classification of asthma severity: should the international guidelines be changed?

International guidelines recommend that, in addition to symptoms and medication requirements, measurements of forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) are necessary for the objective assessment of asthma severity. The guidelines suggest that parity exists between measurements of FEV1 and PEF when expressed as percentage of predicted normal values, and that asthma severity can be classified as mild, moderate or severe on the basis of FEV and PEF measurements of > 80%, 60-80% and < 60% of predicted values, respectively. To determine the relationship between measurements of FEV1 and PEF when expressed as percentage predicted values. A total of 1198 paired measurements of FEV1 and PEF were obtained from the medical records of a random sample of 25 adult asthmatic patients attending a hospital-based chest clinic. Measurements of lung function were expressed as a percentage of predicted normal values, using the European Respiratory Society prediction equations for PEF and FEV1. For the individual paired measurements, the mean differences between PEF and FEV percentage predicted were calculated. Measurements of lung function were used to determine asthma severity with <60%, 60-80%, and >80% predicted FEV1 and PEF values representing severe, moderate and mild asthma, respectively. The proportion of paired measurements in which differences in classification resulted from the use of FEV1 or PEF percentage predicted values was then calculated. In asthma of differing severity, there was considerable variability between measurements of FEV1 and PEF when expressed as percentage predicted values; calculation of the FEV1% predicted resulted in lower values than those of the PEF percentage predicted, with a mean difference of -17.2% (95% CI -16.3%, -18.1%). There was agreement in classification of asthma severity in only 49.9% (598/1198) of paired measurements. Different prediction equations, while variably altering the degree of misclassification, did not correct the basic differences in the assessment of asthma severity dependent on the use of FEV or PEF. FEV1 and PEF values, expressed as percentage predicted, are not equivalent. Pending further evaluation, the authors suggest that published asthma guidelines should avoid the assumption of parity between these two measurements.