PEF Values Research Articles

Asthma Programme in Finland: the quality of primary care spirometry is good

To assess the quality of primary care spirometry by visual inspection of the flow-volume expiratory curve and to study the quantity of clinical information provided on the spirometry report sheets. Retrospective audit of 868 expiratory flow-volume curves referred to three pulmonary clinics assessed against five predefined quality criteria. Clinical information included on the spirometry report sheets was also collected. Quality was good in 78% of pre-bronchodilation curves and in 80% of post-bronchodilation curves. Obtaining a sharp PEF value and full vital capacity exhalation seemed to be the critical points of measurement. Inter-rater reliability of the curve assessment was mainly good. Data on where the spirometry took place, and comments on the use of respiratory medication and patient co-operation were often lacking. The quality of primary care spirometry was good. Adequate clinical information on the report sheets would further improve the quality of this diagnostic process.

The Effects of Different Abdominal Pressures on Pulmonary Function Test Results in Laparoscopic Cholecystectomy

This study aimed to examine the effects of differing intra-abdominal pressures on pulmonary function test results in laparoscopic cholecystectomy. Forty-five patients were operated on under 3 different intra-abdominal pressures: group A (8 mm Hg), group B (12 mm Hg), and group C (15 mm Hg). On the first day before and after the operation, forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC rate, peak expiratory flow speed (PEF), and maximal middle expiration speed (FEF25-75) values were measured using Vmax 229 spirometry. No significant differences were observed among the 3 groups regarding preoperative and postoperative FVC, FEV1, FEV1/FVC, PEF, and FEF25-75 values (P=0.96, P=0.73, P=0.48, P=0.34, and P=0.33, respectively). When the groups' preoperative and postoperative values were compared, FVC, FEV1, and PEF values significantly decreased in each group. The FEF25-75 values statistically significantly decreased in groups B and C when compared with their preoperative values; however, the decrease in group A was not significant. In conclusion, different intra-abdominal pressures during laparoscopic cholecystectomy had similar effects on pulmonary function test results. However, lower intra-abdominal pressures were associated with slightly more negative effects on FEF25-75 values.

Inflammatory and functional effects of increasing asthma treatment with formoterol or double dose budesonide

Adding a long-acting beta(2)-agonist to inhaled corticosteroids (ICS) for asthma treatment is better than increasing ICS dose in improving clinical status, although there is no consensus about the impact of this regimen on inflammation. In this double-blind, randomized, parallel group study, asthmatics with moderate to severe disease used budesonide (400 mcg/day) for 5 weeks (run-in period); then they were randomized to use budesonide (800 mcg/day--BUD group) or budesonide plus formoterol (400 mcg and 24 mcg/day, respectively--FORMO group) for 9 weeks (treatment period). Home PEF measurements, symptom daily reporting, spirometry, sputum induction (for differential cell counts and sputum cell cultures), and hypertonic saline bronchial challenge test were performed before and after treatments. TNF-alpha, IL-4 and eotaxin-2 levels in the sputum and cell culture supernatants were determined. Morning and night PEF values increased in the FORMO group during the treatment period (p<0.01), from 435+/-162 to 489+/-169 and 428+/-160 to 496+/-173 L/min, respectively. The rate of exacerbations in the FORMO group was lower than in the BUD group (p<0.05). Neutrophil counts in sputum increased in both groups (p<0.05) and leukocyte viability after 48 h-culture increased in the FORMO group (p<0.05). No other parameter changed significantly in either group. This study showed that adding formoterol to budesonide improved home PEF and provided protection from exacerbations, although increase of leukocyte viability in cell culture may be a matter of concern and needs further investigation.

STUDY OF PERSONAL BEST VALUE OF PEAK EXPIRATORY FLOW IN PATIENTS WITH ASTHMA : Comparison of the Highest Value of Daily PEF under Good Control and the Highest Value of Daily PEF Obtained after Using Repeated Inhaledβ2-Agonist during High-Dose Inhaled Steroid Treatment

STUDY OF PERSONAL BEST VALUE OF PEAK EXPIRATORY FLOW IN PATIENTS WITH ASTHMA : Comparison of the Highest Value of Daily PEF under Good Control and the Highest Value of Daily PEF Obtained after Using Repeated Inhaledβ2-Agonist during High-Dose Inhaled Steroid Treatment

Efficacy/risk profile of triamcinolone acetonide in severe asthma: Lessons from one case study

Some prednisone-resistant asthma patients respond to intramuscular triamcinolone acetonide (TA). The use of TA has been questioned on the basis of its potential toxicity. TA's ratio of clinical efficacy to systemic effects compared with oral prednisone has not been clearly defined. We report the case of a prednisone-insensitive severe asthma patient with insulin-dependent diabetes, hypertension and diabetic retinopathy treated with repeated sessions of laser therapy. By daily monitoring the needs of insulin doses we compared the systemic effects of prednisone and TA. The analysis of the balance between systemic effects (insulin doses) and beneficial effects (PEF values) show that TA has a better benefit/risk profile than prednisone. The patient has been followed up for 3 years and has received injections of TA repeated at intervals ranging from 21 to 60 days according to patient response and the evolution of PEF and clinical symptoms. During this period the patient lost 3 kg of weight, while presenting increased bone mineral density, normalized arterial tension, and improved proliferative diabetic retinopathy. The present case report shows that TA has a better benefit/risk profile than prednisone. TA can be a valuable alternative in the control of some patients with severe prednisone-resistant asthma.

Need for Rehabilitation in Renal Replacement Therapy Involving Allogeneic Kidney Transplantation

Physical rehabilitation is a form of therapy that complements medical treatment for allogenic kidney transplantation recipients. The aim of this research was to assess the effectiveness of motor therapy among a population of allogenic kidney recipients. Physical rehabilitation was conducted both in the clinic after renal transplantation and over 1 year after the procedure. The 67 patients included 26 women and 41 men of overall average age 44.45 years. The cohort was divided into two subgroups: those undertaking regular exercise ( n = 35) and a control subgroup ( n = 32). The rehabilitation program covered recuperation, isometric, coordination, relaxation, and breathing exercises. Moreover, the following elements were assessed several times: respiratory system (peak expiratory floor [PEF] test), circulatory system, namely, arterial blood pressure and in some cases electrocardiograph, along with the motor system examining upper extremity strength and movement range in distal joints in the upper and the lower extremities. Biochemical blood analysis examined hemoglobin, total protein and albumin, transaminas activity, lactate dehydrogenase, isoenzymes (LD1-5), and creatine kinase (CK), along with CK-MB and CK-MM. A significant improvement was observed in the range of movement in the radiocarpal joint ( P < .05) and an increased PEF value ( P < .05). Among the total kidney transplantation recipients, 81.3% of patients subjected to rehabilitation and 77.8% the control subgroup accepted the need for long-term motor exercise. The analysis of the implemented rehabilitation program, and biochemical analyses confirmed the need to establish rehabilitation centers, for example, in dialysis centers and/or transplant institutes, for patients subjected to renal replacement therapy, and particularly after successful kidney transplantation.

Validez en el registro del pico espiratorio máximo de niños asmáticos de la Ciudad de México

To determine the concordance between maximum peak expiratory flow records (PEFr) reported by the parents of asthmatic children and the electronic values stored by the AirWatch device (PEFe). Records of PEF measurements between October 1998 and 1999 were obtained from 42 asthmatic children 5 to 15 years of age recruited at the Hospital Infantil de Mexico Federico Gomez, in Mexico City. Parents recorded the maximum value in the health diary. Spearman correlation was calculated between PEFe and PEFr and a mixed-effects logistic model was used. The correlation between PEFe and PEFr was r=0.96 (p<0.05) among children with a diagnosis of moderate or severe asthma and r=0.40 (p<0.05) among children diagnosed with mild asthma. Follow-up time, asthma severity, gender and age of the child and their interactions were predictors of the differences between PEFe and PEFr. Parents of children with moderate or severe asthma from 6 to 8 years of age report PEF values with greater accuracy during follow-up than others.

Pulmonary function testing in New Zealand: The use and importance of reference ranges

The diagnosis, assessment and management of a wide range of respiratory diseases rely on accurate interpretation of lung function tests through the use of reference equations to generate predicted values. This paper ascertains the suitability of reference equations currently used in New Zealand through comparison with newly derived equations from the Wellington Respiratory Survey, and discusses the relevance of the findings to the Asia Pacific region. A survey of lung function testing facilities determined the reference equations in common usage. Pulmonary function test results from healthy, lifelong non-smoking subjects (n = 180) were expressed as percentage predicted values, with comparisons made between the currently used and Wellington Respiratory Survey reference equations. Differences in disease severity classification in subjects with COPD (n = 46) and asthma (n = 61) were determined, using the different reference equations. Currently used equations significantly underpredict measured values for FEV(1), PEF, TLC and RV by up to 20%. Severity classification of COPD and asthma based on per cent predicted FEV(1) was substantially altered by the choice of reference equation. Many reference equations in current usage in New Zealand are no longer suitable for use. The applicability of reference equations used in other populations and countries within the Asia Pacific region requires further investigation. We recommend that up-to-date reference equations are derived and implemented if those currently used are shown to be unsatisfactory.

Occupational hazards and safety measures among stone quarry workers in northern Nigeria

The health conditions of workers all over the world vary widely, depending among others on the geographical location, the type of employment and the patterns of work. The study was undertaken to determine the occupational hazards, and safety measures among Stone quarry workers in Zaria, Northern Nigeria. It involved the administration of questionnaires to all the workers in the quarry in Zaria City in order to obtain data on socio-demographic characteristics, occupational profile, hazards, safety measures and PEAK flow measurement. A total of seventy four workers were interviewed, their age ranged from 15-50yrs. Majority of the workers were in the age group 25-29 yrs [37.8%]. Most of the workers had injuries/cuts from stones 68.9%, respiratory symptoms [nasal discharge [52.3%], eye irritations 14.9%. A worker had traumatic amputation of Right thumb. PEF values of most (55.4%) of the workers were abnormal. Most workers are at serious risk of ill-health and injuries/accidents because of the conditions they encounter in their workplaces. All the quarry sites had no preventive/safety measures for the workforce; nor recreational lavatory facilities. There is urgent need on the part of the Federal Ministry of Solid Minerals to institute and enforce measures to prevent this menace. This requires a multi-disciplinary approach. Research into occupational hazards in stone quarry needs to be pursued vigorously. Keywords : occupational hazards; safety measures; stone quarries Nigerian Medical Practitioner Vol. 50 (2) 2006: pp 42-47

Lung function after acute and repeated exposures to extremely cold air (−110°C) during whole‐body cryotherapy

Whole-body cryotherapy (WBC) is one mode of cold therapy, during which rheumatic patients are exposed to very cold air (-110 degrees C) in minimal clothing. It is also proposed to have a bronchodilatory effect. The aim was to examine the effects of WBC on lung function in healthy humans after acute and repeated exposures. Twenty-five healthy, non-smoking subjects participated in the study. They were exposed to WBC for 2 min three times per week for 12 weeks. The peak expiratory flow rate (PEF) and forced expiratory volume in 1 s (FEV1) were measured before and after (at 2 and 30 min) the first WBC, and then similarly at 4, 8 and 12 weeks. At all time points, after 30 min of the WBC the PEF values were slightly lower compared with values before the WBC, and the reductions reached statistical significance at 1 month (5.1 +/- 1.2%), and at 3 months (3.2 +/- 1.7%). After 30 min of the first WBC, the FEV1 was significantly reduced by 2.3 +/- 0.8%, but no other changes were observed during the study. In conclusion, the WBC induced minor bronchoconstriction in healthy humans instead of proposed bronchodilatation. The WBC seems not to be harmful for lung function, but should be used with caution in susceptible individuals.

Of smoking habit on respiratory function in young asthmatics: Follow-up study from 16-30 years of age

Smoking habit of 54 asthmatics was followed for 15 years. To examine if there was any difference of lung function tests between smoking and nonsmoking young asthmatics. Based on questionnaires, clinical examinations, lung function tests and skin prick tests, 54 adolescents with asthma were separated out of 1134 pupils of one Belgrade high school. They were followed-up till the age of 30. 62.9% of subjects were females and 37.1% were males. Average age at the beginning was 16.3 and 29.6 at the end of study. In 13.0% of subjects, the asthma manifested in the first year of life, in 72.2% between 2-6 years of age and in 14.8% of our subjects, the asthma developed after 7th year. The symptoms of asthma in last 12 months were present in 54.8% of our subjects at the age of 16, compared to 77.8% of asthmatics with asthma symptoms at the age of 30. Percent of smokers increased cumulatively from 16.7% at the beginning of study up to 57.5% upon its completion. Number of cigarettes increased from 7.5% to 16.5% cig/day in a smoker from the adolescent period until the end of study, with no difference in relation to sex. Average duration of smoking experience was 11.5 years, no difference in relation to gender. Values of VC, FVC, FEV1, PEF and MEF75 were always lower in asthmatics-smokers, but with no statistical difference. Tiffeneau index, MEF25 and MEF50 were statistically lower in the smoking group at the age of 30 compared to their values at the age of 21. Smoking does affect lung function of asthmatics that started to smoke and Tiffeneu index, MEF25 and MEF50 were statistically lower as early as at the age of 30.

Acute asthma in children: Treatment with oral prednisone vs. intravenous methylprednisolone

RATIONALE: To compare the efficacy of an oral corticosteroid (prednisone) vs. an IV corticosteroid (methylprednisolone) for the treatment of mild or moderate asthma exacerbations. METHODS: We studied 87 patients, ages 6 to 12, who visited the emergency room of a pediatric hospital with acute, mild or moderate asthma, between March and December 2003. Two treatment groups were randomized to receive; Group A: 30 mg of IV methylprednisolone (n=43), Group B: 30 mg of oral prednisone (n=44). Both groups received nebulized albuterol 0.15 mg/kg/dose every 20 minutes. Patients were evaluated every two hours and clinical improvement was considered by symptoms relief, rise in PEF and pulse oxymetry values. The follow up period was 6 hr, when discharge or admission was decided. Statistics: Non paired ANOVA test, P significative if <0.05. RESULTS: At the beginning both groups were similar. After the second evaluation (4 hours), 36 patients (83.7%) for group A vs. 38 patients (86.3%) for group B were discharged because of clinical improvement. At the end of the follow up period (6 hours), 4 patients for each group (9.3% and 9.0% respectively) were hospitalized for symptoms persistence. Intergroup differences were not significative in any of three evaluations. CONCLUSIONS: Oral prednisone proved to be as effective as IV methylprednisolone in treating mild or moderate asthma exacerbations, by improving symptoms and rise PEF and pulse oxymetry values. Therefore we recommend oral prednisone because is effective, non-traumatic and less expensive.

The Influence of Gastroesophageal Reflux Disease and its Treatment on Asthmatic Cough

Gastroesophageal reflux is known to cause chronic cough and is also implicated in worsening of asthma. We conducted a prospective study to examine the clinical significance of gastroesophageal reflux disease (GERD) in asthmatic patients with chronic cough to analyze the temporal relationship between reflux events and coughing and to assess the effect of esomeprazole treatment on respiratory symptoms and lung function in these patients. Asthmatic patients (126) with chronic dry cough were studied. Diagnosis of GERD was based on typical symptoms and the effectiveness of therapeutic test or on pH monitoring. Patients without GERD (negative pH results) consisted of the control group. The results of pH monitoring showed that 64% of cough episodes were related to acid reflux and in 91% of reflux events preceded coughing. Esomeprazole treatment (40 mg/day for 3 months) not only diminished GERD symptoms but also improved asthma outcome Baseline FEV(1) and PEF values increased significantly together with a decrease in symptom scores and the use of rescue medication. In most patients included in the extended part of the study for another 3 months, the dose of inhaled steroids could be reduced with sustained GERD therapy. Our data showing that reflux events preceded coughing in most cases and that treatment of GERD resulted in an improvement in different outcome measures of asthma suggest that GERD worsens asthma, and its treatment is of clinical importance to effectively manage these patients.

Salmeterol/Fluticasone Propionate versus Fluticasone Propionate Plus Montelukast

Asthma, owing to its chronic nature, is associated with a substantial economic burden. Healthcare providers need to compare the cost effectiveness of alternative asthma treatment options to ensure that they obtain the best value for money from the resources they control. The objective of the current study was to compare the cost effectiveness of salmeterol/fluticasone propionate in combination with fluticasone propionate plus montelukast in patients with symptomatic asthma uncontrolled with inhaled corticosteroid (ICS) monotherapy. Direct healthcare resource data were prospectively collected during a double-blind, randomized, 12-week clinical study of inhaled salmeterol/fluticasone propionate 50/100 microg twice daily (n = 356) and inhaled fluticasone propionate 100 microg twice daily plus oral montelukast 10mg daily (n = 369). Resources were costed in Dutch guilders (NLG) from the perspective of The Netherlands healthcare system using 1999/2000 prices, but have been presented in US dollars and euros. The primary effectiveness measure was the proportion of successfully treated weeks (based on mean morning PEF values). Secondary measures were episode-free days, symptom-free days, and symptom-free nights. Salmeterol/fluticasone propionate was more effective than fluticasone propionate plus montelukast as measured by the proportion of successfully treated weeks mean 63.3% vs 39.0%; median difference 25%; p < 0.001). Salmeterol/fluticasone propionate was also more effective than fluticasone propionate plus montelukast according to the secondary effectiveness measures. The mean total direct daily healthcare costs per patient were 16% higher with fluticasone propionate plus montelukast than with salmeterol/fluticasone propionate mainly due to higher drug costs in the former group (2.25 US dollars vs 1.94; 1.92 euro vs 1.66, respectively; the NLG was fixed against the euro at a rate of 1 euro = NLG2.2 on 31 December 1998; 1 US dollars = NLG1.883, June 2003; 1 US dollars= 0.848 euro, June 2003). Incremental cost-effectiveness analyses showed that salmeterol/fluticasone propionate was dominant over fluticasone propionate plus montelukast and sensitivity analyses showed these results to be robust. Salmeterol/fluticasone propionate is a more cost-effective treatment option than fluticasone propionate plus montelukast for patients with symptomatic asthma uncontrolled by ICS.

Effects of different anti‐asthmatic agents on induced sputum and eosinophil cationic protein in mild asthmatics

Inhaled corticosteroids, leukotriene receptor antagonists, and theophylline are recommended for the treatment of mild persistent asthma. The aim of this study was to compare the changes in sputum total cell and eosinophil counts, and eosinophil cationic protein (ECP) levels in serum and sputum following treatment with leukotriene receptor antagonists, inhaled corticosteroids, and theophylline in patients with mild persistent asthma. Total cell counts, eosinophil percentage, and ECP levels in induced sputum and serum were determined both before and after treatment. Prior to sputum induction, FEV1 and PEF values and symptom scores were recorded at baseline and after 8 weeks of treatment. After baseline measurements, the asthmatic patients (n = 30) were randomized into three groups. A total of 10 patients were treated with zafirlukast, 20 mg bd, 10 with budesonide inhaler 200 microg bd, and 10 with theophylline 200 mg bd. There were significant decreases in sputum total cell counts and eosinophil percentage in all treatment groups. However, the decrease in sputum eosinophil counts was more significant in the corticosteroid-treated group. Although sputum ECP levels decreased significantly in the groups treated with zafirlukast and budesonide (zafirlukast group, 580-135 microg/L, P < 0.01; budesonide group, 683-268 microg/L, P < 0.01), the decrease was not statistically significant in the theophylline-treated group (498-361 microg/L, P > 0.05). In contrast, there were no significant changes in serum ECP levels in any of the treatment groups. All three treatments resulted in significant decreases in sputum total cell counts and eosinophil percentage, but the decrease in sputum ECP level was only seen in the groups treated with budesonide and zafirlukast. These results suggest that although all three treatments are considered as first-line treatments in most consensuses, theophylline seems to have less of an inhibitory effect on eosinophil activation.

Respiratory risks in tunnel construction workers.

Respiratory diseases are frequent in tunnel construction workers. A group of 144 subjects randomly selected from the population of 2516 workers engaged in the construction of the railway tunnel under the Appennine Mountains, from Bologna to Firenze was investigated. A group of 69 males comparable for age, living area and habits was studied as a control group. Assessment of air pollutants (NO, NO2, SO2, total dust, silica %) was carried out by means of fixed monitoring stations as well as personal monitors. All the subjects included in the study were examined with a standardised protocol which included physical examination, lung function tests (before and after shift work) and a questionnaire to college respiratory symptoms. Low concentrations of environmental pollutants were evidenced. Significantly lower values of FEV1 and PEF were determined in the worker group pared to controls. A significant decrease in respiratory parameters was shown after shift work. Variables capable of influencing the decrease in parameters include smoking habits, work activity, presence of cough and expectoration, period of the year (spirometries resulted worse in the winter time). Significantly lower values of FEV1 and PEF were evidenced in the workers compared to controls. In spite of the present low work environmental exposure conditions, some physiologic parameters appear altered in tunnel construction workers. This may depend on a variety of noxious agents present in the working environment.

Variability in asthma severity/control in pediatric asthma patients previously receiving short-acting beta 2-agonists

Rationale Though it is widely believed that there is a high degree of variability in asthma severity/control in pediatric asthma patients, few studies have evaluated this assumption. Methods An analysis of 5 previously conducted, 12-week asthma studies was done to evaluate asthma variability in pediatric patients randomized to placebo. Patients were stratified into 2 age groups: 4-7 years (n=98) and 8-11 years (n=178) with baseline PEF %predicted=78-81%; over 60% of patients had moderate/severe asthma at baseline. Results Pediatric patients receiving placebo exhibited marked fluctuations in asthma severity. Patients aged 4-7 spent approximately 30%, 18%, 43% and 9% of weeks in the intermittent, mild, moderate and severe categories, respectively, based upon PEF, symptoms and albuterol use and patients aged 8-11 spent 26%, 17%, 50% and 7% of weeks, respectively. Over 65% of patients aged 4-7 experienced ≥5 changes in their asthma severity classification based upon PEF during the 12-week studies. For these patients, baseline PEF %predicted was 71.6% compared with 89.7% in patients who changed <5 times. In patients aged 8-11, approximately 60% had ≥5 changes in their asthma severity classification based upon PEF. For these patients, baseline PEF %predicted was 73.7% compared with 89.6% in patients who changed <5 times. Baseline values for PEF % predicted did not differ in patients whose PEF changed 5-20 times versus >20 times. Conclusion This analysis clearly demonstrates that asthma severity/control is highly variable in pediatric asthma patients and patients frequently move between severity categories. However, baseline PEF does not predict which patients will exhibit marked variability.

Montelukast in early childhood asthma. Predict value of Igg in clinical reply in children 2 to 5 years old?

BackgroundAccording to current knowledge, asthma is basically an inflammatory process. Its causes and physiopathological mechanisms are various. The final result is a recurrent obstructive bronchial process, with sibilants and/or dypnea, which causes an upset in functional respiratory tests, among which the maximum respiratory peak flow meter diminished for the age, sex, and height of patient AimsOur aim is to evaluate if response to treatment with Montelukast has any link with immnuloglobin values (IgG, IgA, IgM, IgE) at start of treatment Materials and methodsIncluded in the study were 32 children, of whom 2 did not begin and 1 who did not provide personal data. There were 29 patients in total, 11 girls and 18 boys. Each made three visits: first where they were instructed, together with their parents, in how to manage the meter and where they received the peak flow meter, Vitalograph, and personal data sheet, where personal and family medical history were noted. The second visit was after 4 weeks, for a clinical assessment and the third visit after 8 weeks. The value register of the PEF would be made morning and night, noting the highest value of three measurements. IgG, IgA, IgM, IgA values were quantified before treatment began. The statistic package STATA 2001 was used in the treatment of data statistics ResultsOur between the value reached by the PEF after treatment and the IgG values at the beginning of treatment (0.712). In lesser measurement for IgA values (0.660). For each 100 mg/ml of increase in the value of IgG, an increase of 10 l/min in the PEF measurement before and following treatment with Montelukast was produced ConclusionsIgG values increase with age. Children with a greater IgG value at the beginning of treatment reached higher PEF values after same. It is not known if the results would be similar with another type of treatment and the way in which IgG influences the results. What appears to be confirmed by available studies is that this relation is found in a group of small children, the aim of our study

Pulmonary dysfunction in transfusion-dependent patients with thalassemia major.

Pulmonary function tests were performed on 62 transfusion-dependent patients with thalassemia major, ranging in age from 8 to 33 years, and receiving chelation therapy with desferrioxamine or deferiprone. Percent predicted values for FVC, FEV1, and PEF were significantly reduced, whereas FEV1/FVC and maximal expiratory flow at 25% FVC were within normal limits, indicating a restrictive disease. Both FVC and FEV1 were negatively correlated with transfusional iron burden as indexed by age. Single-breath carbon monoxide transfer factor was reduced, even after correction for low hemoglobin concentration, and was negatively correlated with iron burden and iron overload, as indexed by serum ferritin levels. Owing to low hemoglobin concentration, blood-diffusing capacity was reduced, in spite of increased lung capillary blood volume, which was, however, adequate to normalize blood diffusing capacity when hemoglobin concentration was only partially restored by transfusion. The diffusing capacity of the alveolar-capillary membrane was substantially decreased and negatively correlated with age and serum ferritin, the fall being primarily attributed to increased membrane thickness. These findings suggest that lung fibrosis and/or interstitial edema related to iron overload are the main cause of pulmonary dysfunction observed in patients with thalassemia major.

The relationship between FEV1 and PEF in the assessment of the severity of airways obstruction.

International consensus guidelines suggest that in asthma and chronic obstructive pulmonary disease (COPD), measurements of FEV1 and PEF are equivalent in the assessment of the degree of airflow obstruction when expressed as the per cent of predicted values. In this retrospective study, 2,587 paired measurements of PEF and FEV1 performed by 101 adult patients with asthma (n = 56) and COPD (n = 45) attending an outpatient chest clinic were obtained. The mean differences between FEV1 and PEF measurements when expressed as the percentage of predicted values was determined. The level of agreement between the two measurements in the classification of asthma severity (life-threatening, severe, moderate and mild asthma determined by PEF or FEV1 measurements of <30%, 30-60%, 60-80%, and >80% of the predicted values, respectively) was determined. There was considerable variability between measurements of FEV1 and PEF when expressed as % predicted values. In both asthma and COPD, the FEV1% predicted was smaller than the PEF % predicted, with the mean difference being -10.9% (95% CI, -12.8% to -8.9%) with limits of agreement of -35.4% to +13.6%. The weighted Kappa statistic for agreement was 0.59 (95% CI, 48-70%) in the classification of the severity of airflow obstruction. When expressed as percentage of predicted values, PEF and FEV1 values are not equivalent. We recommend that guidelines be modified to state that across the spectrum of the severity of airflow obstruction there is considerable variability between measurements of FEV1 and PEF when expressed as % predicted such that the FEV1 may be as much as 35% lower or up to 15% higher than the PEF for patients with obstructive lung diseases.