Dataset concerning the analytical approximation of the Ae3 temperature

In this paper we present a new polynomial function for calculating the local phase transformation temperature (Ae₃) between the austenite+ferrite and the fully austenitic phase fields during heating and cooling of steel:Ae3(°C)=c0+∑X,kcXkXk+∑X,Y,k,mcXkYmXkYm+∑X,Y,Z,k,m,ncXkYmZnXkYmZn

The dataset includes the terms of the function and the values for the polynomial coefficients for major alloying elements in steel. A short description of the approximation method used to derive and validate the coefficients has also been included. For discussion and application of this model, please refer to the full length article entitled “The role of aluminium in chemical and phase segregation in a TRIP-assisted dual phase steel” 10.1016/j.actamat.2016.05.046 (Ennis et al., 2016) [1].

Dose dependent increased mortality risk in COPD patients treated with oral glucocorticoids

Systemic corticosteroids are often administered in COPD patients. The relationship between systemic glucocorticoids and mortality in patients with moderate to severe chronic obstructive pulmonary disease (COPD) was retrospectively analysed. Baseline characteristics of the patients, in stable clinical condition, were collected on admission to a pulmonary rehabilitation centre. Overall mortality was asessed at the end of follow-up. The Cox proportional hazards model was used to quantify the relationship between glucocorticoid use, distinguishing administration route (oral/inhalation) and oral dose, and overall mortality, adjusted for the influence of age, sex, smoking, lung function, resting arterial blood gases and body mass index. On multivariate analysis, oral glucocorticoid use at a (prednisone equivalent) dose of 10 mg x day(-1) without inhaled glucocorticoids, was associated with an increased risk (RR=2.34, 95% confidence interval (CI) 1.24-4.44) while 15 mg x day(-1) carried a relative risk of 4.03, CI = 1.99-8.15). A significant interaction was observed between inhaled and oral glucocorticoid use. Combined with inhaled glucocorticoids, the relative risk of oral glucocorticoid use appeared to be significantly smaller. It is concluded that in severe chronic obstructive pulmonary disease, maintenance treatment with oral glucocorticoids is associated with increased mortality in a dose-dependent manner. Since the present study design cannot exclude the possibility of bias by indication, further prospective studies are indicated using a broader patient characterization.

Tissue depletion and health related quality of life in patients with chronic obstructive pulmonary disease

The relationship between tissue depletion and decreased exercise performance has been well established in patients with COPD. In this study we investigated the influence of the pattern of tissue depletion on health related quality of life (HRQL) and their mutual relationship with exercise capacity and dyspnoea. Patients with low body weight and/or low fat-free mass (FFM; using bioelectrical impedance) were categorized in three groups according to type of tissue depletion: loss of both FFM and fat mass (FM), and loss of FFM or FM only. Handgrip strength (HGS) was used as a functional outcome measure of tissue depletion. Exercise performance was assessed by 12 min walking distance (12MWD) and dyspnoea by visual analogue scale (VAS). HRQL was measured with the St George's Respiratory Questionnaire (SGRQ) and the Medical Psychological Questionnaire for Lung diseases (MPQL). Patients with depletion of FFM irrespective of body weight showed greater impairment in 12MWD, HGS, the 'activity' and 'impact' scores of the SGRQ and the domain 'invalidity' of the MPQL, in comparison with depleted patients with relative preservation of FFM. Exercise performance and dyspnoea were also significantly related to these subscores of HRQL. In addition, dyspnoea related significantly to the domain 'symptoms' of the SGRQ. Tissue depletion pattern remained significantly related to SGRQ-scores and the domain 'invalidity' of the MPQL when dyspnoea and walking distance were added to the model as a covariates. Tissue depletion is an important determinant of HRQL independent of exercise capacity and dyspnoea.

Interval versus continuous training in patients with severe COPD: a randomized clinical trial

Limited information is available regarding the physiological responses to different types of exercise training in patients with severe chronic obstructive pulmonary disease (COPD). The aim of this study was two fold: firstly, to investigate the physiological response to training at 60% of achieved peak load in patients with severe COPD; and secondly to study the effects of interval (I) versus continuous (C) training in these patients. Twenty-one patients with COPD (mean+/-SD forced expiratory volume in one second: 37+/-15% of predicted, normoxaemic at rest) were evaluated at baseline and after 8 weeks' training. Patients were randomly allocated to either I or C training. The training was performed on a cycle ergometer, 5 days a week, 30 min daily. The total work load was the same for both training programmes. C training resulted in a significant increase in oxygen consumption (V'O2) (17%, p<0.05) and a decrease in minute ventilation (V'E)/V'O2 (p<0.01) and V'E/carbon dioxide production (V'CO2) (p<0.05) at peak exercise capacity, while no changes in these measures were observed after interval training. During submaximal exercise a significant decrease was observed in lactic acid production, being most pronounced in the C-trained group (-31%, p<0.01 versus -20%, p<0.05). Only in the I-trained group did a significant increase in peak work load (17%, p<0.05) and a decrease in leg pain (p<0.05) occur. Training did not result in a significant improvement in lung function, but maximal inspiratory mouth pressure increased in both groups by 10% (C: p<0.05) and 23% (I: p<0.01). The present study shows a different physiological response pattern to interval or continuous training in chronic obstruction pulmonary disease, which might be a reflection of specific training effects in either oxidative or glycolytic muscle metabolic pathways. Further work is required to determine the role of the different exercise programmes and the particular category of patients for whom this might be beneficial.

Effects of specialized community nursing care in patients with chronic obstructive pulmonary disease

OBJECTIVE

To investigate the effects of specialized respiratory home nursing care after discharge from a pulmonary rehabilitation center.

DESIGN

Pretest-posttest control group design. Patients in the experimental group were visited by a nurse who specializes in respiratory care, whereas the control group received care from nurses who did not specialize in respiratory care.

SETTING

Data were collected on admission, at program discharge, and 4 months and 9 months after discharge from a pulmonary rehabilitation center.

PATIENTS

One hundred fifteen patients were included in the study and observed for 1 year.

OUTCOME MEASURES

Health-related quality of life (HRQL), coping strategies, compliance, hospitalization, and satisfaction with the care provided.

RESULTS

Complete data sets were obtained from 78 patients with severe airflow obstruction (FEV1 = 41%; predicted +/- SD = 15). Corrections were made for the selective nonresponse, but did not lead to adjustments in outcome scores. In both groups, HRQL scores improved between admission and discharge, but deteriorated 4 months and 9 months after discharge. The only statistically significant short-term effect was found on the "activities" component of HRQL in favor of the control group. No differences were found between groups regarding coping, compliance, and hospitalization. Patients in the experimental group, however, were more satisfied with the care provided by the specialized community nurses.

CONCLUSIONS

The treatment intervention of specialized respiratory home nursing might not have been specific or intensive enough to result in outcome benefits. Secondly, the initial benefits from baseline pulmonary rehabilitation alone may have led to positive outcomes in both patient groups.

Analysis of the metabolic and ventilatory response to self-paced 12-minute treadmill walking in patients with severe chronic obstructive pulmonary disease

BACKGROUND

The 12-minute walking test is frequently used to measure exercise capacity in patients with severe chronic obstructive pulmonary disease. However, the physiological response to this test has been the subject of limited investigation.

METHODS

In this study, the metabolic and ventilatory consequences of a self-paced 12-minute treadmill walking test (WT) were measured in 17 patients with severe chronic obstructive pulmonary disease (FEV1: 40 +/- 9%) and evaluated using the physiological response to symptom-limited cycle ergometry (CE). During exercise testing, heart rate, transcutaneous oxygen saturation, and lactate concentration were measured, and oxygen consumption, carbon dioxide production, tidal volume, and breathing frequency were recorded breath by breath.

RESULTS

After 4 minutes walking, the peak oxygen consumption (VO2) was already 99 +/- 11% of last-minute walking VO2. Walking speed was chosen within 2 minutes and remained stable throughout the test. The WT and CE showed similar (end-) test results for all measurements, except for a higher carbon dioxide production, venous lactate concentration, and respiratory quotient after CE. However, lactate concentration was also significantly increased after WT. Severe and prolonged desaturation was shown during walking in most patients.

CONCLUSIONS

The physiological stress evoked during the WT is close to the stress developed at an incremental symptom-limited test and the relatively high metabolic and ventilatory stress is sustained from at least 4 to 12 minutes during the WT. This study has shown that anaerobic metabolism not only occurs during incremental cycle ergometry, but also during the WT.

Peak exercise response in relation to tissue depletion in patients with chronic obstructive pulmonary disease

In several studies a correlation between body weight and peak exercise capacity has been found in patients with chronic obstructive pulmonary disease (COPD). In the present study a thorough analysis of the relationship between body composition and peak exercise performance was executed in 62 patients with clinically stable COPD. This was based on the hypothesis that particularly muscle mass, as the largest constituent of both fat-free mass (FFM) and body cell mass, is related to exercise capacity. Body composition was assessed using deuterium and bromide dilution techniques, to measure total body water (TBW) and extracellular water. From these measurements FFM:TBW/0.73, the ratio of ECW/intracellular water (ICW) and ICW-index (ICW/height2) were calculated. Peak exercise performance was measured using an incremental cycle ergometry test. The transfer factor of the lung for carbon monoxide (TL,CO) intrathoracic gas volume (ITGV), maximal expiratory and inspiratory mouth pressure, forced expiratory volume in one second (FEV1), FFM-index (FFM/height2), body mass index (weight/height2) and ICW-index correlated strongly (p<0.01) to peak oxygen consumption (V'O2). The ratio ECW/ICW correlated only weakly, but significantly, with peak V'O2 (r=-0.25, p<0.05). Stepwise regression analysis demonstrated that FFM-index and TL,CO explained 53% of the variation in peak V'O2. The results of this study furthermore indicate that severe FFM depletion is related to a blunted tidal volume response to peak exercise, a decreased peak oxygen pulse and an early anaerobic metabolism in patients with COPD. Depletion of muscle mass, measurable by assessment of fat-free mass, significantly effects peak oxygen consumption, ventilatory response, the oxygen pulse and anaerobic energy metabolism in patients with chronic obstructive pulmonary disease.

Long-term outcome of pulmonary rehabilitation in patients with COPD

BACKGROUND

This study investigates the long-term benefits of pulmonary rehabilitation in terms of health-related quality of life (HRQL). Such information is of particular importance in developing strategies for aftercare at home which aim to maintain the initial improvements seen after rehabilitation.

METHODS

Criteria for inclusion were diagnosis of COPD, age 40 to 80 years, and completion of an inpatient pulmonary rehabilitation program. HRQL was assessed by the St. George Respiratory Questionnaire, and the component "well-being" from the Medical Psychological Questionnaire for Lung Diseases. Patient characteristics included lung function parameters such as FEV1, the diffusion capacity for carbon monoxide and maximal inspiratory mouth pressure, age, socio-economic variables, and exercise tolerance evaluated by a 12-min walking test. To define patients in whom long-term benefits were sustained 9 months postdischarge, cases were clustered using hierarchical cluster analysis, based on the HRQL scores at discharge.

RESULTS

Complete data sets were obtained from 77 patients. Two groups of cases were clustered. Patient characteristics were essentially the same in both groups. HRQL differed significantly between groups on admission, at discharge, and at follow-up. Within-group analysis revealed that patients in group 1 (n=44) had "moderate" scores on HRQL on admission, a significant improvement between admission and discharge, followed by a significant deterioration of HRQL at follow-up. Group 2 (n=33) had "severely" impaired HRQL on admission, little improvement after rehabilitation, and remained in fairly stable condition 9 months postdischarge.

CONCLUSIONS

Results suggest that patients with COPD require a differentiated aftercare program of postdischarge pulmonary rehabilitation.

Determinants of health-related quality of life in patients with chronic obstructive pulmonary disease

BACKGROUND

The consequences of chronic obstructive pulmonary disease (COPD) on daily life, encapsulated by the term "health-related quality of life" (HRQL), are important in determining appropriate home care. There is a need to understand the relative contribution of respiratory impairment, physical disability, coping, age, and socioeconomic variables on HRQL.

METHODS

Patients with COPD were recruited on admission to a pulmonary rehabilitation centre. Respiratory impairment was assessed by lung function tests and physical disability was evaluated by a 12 minute walking test. HRQL was assessed by means of the St George's Respiratory Questionnaire (SGRQ) measuring "symptoms", "activity", and "impact". Because the SGRQ does not include a measure of "well being", this was taken from the medical psychological questionnaire for lung diseases. The COPD coping questionnaire and a questionnaire covering basic socioeconomic variables were also used.

RESULTS

One hundred and twenty six patients of mean (SD) age 65 (9) years and mean (SD) forced expiratory volume in one second (FEV1) 39 (9)% predicted were included. The scores on the SGRQ indicated severe impairment. Correlations were found between lung function parameters, 12 minute walking test, and the HRQL "activity" and "impact" components. Coping strategies were correlated with the "activity", "impact", and "well being" components. No correlations were found between age, socioeconomic variables, and HRQL. FEV1, 12 minute walking test, and the coping strategies "avoidance" and "emotional reaction" were the best predictors of HRQL.

CONCLUSION

In patients with COPD methods of improving physical performance and teaching adequate coping strategies should be considered in order to improve HRQL.

Physiologic effects of nutritional support and anabolic steroids in patients with chronic obstructive pulmonary disease. A placebo-controlled randomized trial

Nutritional depletion commonly occurs in patients with COPD, causing muscle wasting and impaired physiologic function. Two hundred seventeen patients with COPD participated in a placebo-controlled, randomized trial investigating the physiologic effects of nutritional intervention alone (N) for 8 wk or combined with the anabolic steroid nandrolone decanoate (N + A). Nandrolone decanoate or placebo (P) was injected intramuscularly (women, 25 mg; men, 50 mg) in a double-blind fashion on Days 1, 15, 29, and 43. Nutritional intervention consisted of a daily high caloric supplement (420 kcal; 200 ml). Also, all patients participated in an exercise program. In the depleted patients, both treatment regimens induced a similar significant body weight gain (2.6 kg) but different body compositional changes. Particularly in the last 4 wk of treatment, weight gain in the N group was predominantly due to an expansion of fat mass (p < 0.03 versus P and N + A), whereas the relative changes in fat-free mass (FFM) and other measures of muscle mass were more favorable in the N + A group (p < 0.03 versus P). Maximal inspiratory mouth pressure improved within both treatment groups in the first 4 wk of treatment, but after 8 wk only N + A was significantly different from P (p < 0.03). Nutritional supplementation in combination with a short course of anabolic steroids may enhance the gain in FFM and respiratory muscle function in depleted patients with COPD without causing adverse side effects.

Metabolic and ventilatory response pattern to arm elevation in patients with COPD and healthy age-matched subjects

Many patients with chronic obstructive pulmonary disease (COPD) experience problems in those activities of daily living which involve so-called unsupported arm elevations (AE). In this study, possible differences in the metabolic and ventilatory response pattern to three types of arm elevation were compared between 13 COPD patients (forced expiratory volume in one second (FEV1) (mean (SD)) 38 (13)% of predicted) and 13 age-matched healthy subjects. Each subject consecutively performed three types of arm elevation for 2 min, with 3 min rest periods in between. Breath-by-breath metabolic and ventilatory parameters and heart rate (HR) were registered during a 3 min baseline period and throughout the measurement period. Adjusted for significantly greater baseline test results in COPD patients, it was found that AE (arm elevation including recovery) tended to be more demanding with respect to metabolic and ventilatory response for patients with COPD than for the age-matched healthy subjects. Arm elevation resulted in an increase in oxygen consumption (V'O2) (COPD 12%; healthy 6%), carbon dioxide elimination V'CO2 (COPD 15%; healthy 10%), minute ventilation V'E (COPD 13%; healthy 7%) and heart rate (COPD 2%; healthy 5%). A pronounced difference was found in the pattern of metabolic and ventilatory response to arm elevation, i.e. there was an earlier but sluggish V'O2 onset in COPD patients, whereas the healthy subjects demonstrated a sudden peak approximately 30 s after arm elevations. Mutual comparison of the three different types of arm elevation demonstrated a comparable response pattern. Knowledge of the specific response to arm elevations in COPD patients seems essential for interpretation of arm elevation tests in upper extremity rehabilitation programmes.

Prevalence and characteristics of nutritional depletion in patients with stable COPD eligible for pulmonary rehabilitation

Prevalence and characteristics of nutritional depletion were established by body composition measurements in 255 COPD patients in stable clinical condition admitted to a pulmonary rehabilitation center. Depletion of body weight, fat-free mass (using bioelectrical resistance measurements), and muscle mass [from creatinine height index (CHI) and midarm muscle circumference] was most pronounced (40 to 50%) in patients suffering from chronic hypoxemia and in normoxemic patients with severe airflow obstruction (FEV1 < 35%) but also occurred in +/- 25% of patients with moderate airflow obstruction. Classification of the patients in four groups by body weight and fat-free mass revealed that depletion of fat-free mass may occur in normal-weight COPD patients (Group 3). These patients also exhibit a decreased CHI (61 +/- 21%, mean +/- SD) and suffer from physical impairment (12-min walking distance, WD, 532 +/- 152 m) to an even greater degree than underweight patients with relative preservation of fat-free mass (Group 2) (CHI = 73 +/- 16%; WD = 744 +/- 233 m). No systematic differences were established between the four groups in serum protein concentrations or medication use. We conclude that fat-free mass is a better indicator of body mass depletion than body weight. Classification of COPD patients by body weight and fat-free mass may have consequences for planning and interpretation of intervention strategies, particularly in Group 2 and 3 patients.

A comparison of the effects of anticholinergic and beta 2-agonist and combination therapy on respiratory impedance in COPD

The effects of three different regimens of inhaled bronchodilators on spirometry and respiratory impedance as measured with the technique of forced oscillations were compared in a double-blind crossover study in 22 patients with stable chronic obstructive pulmonary disease (FEV1 less than 70 percent predicted). On three trial days, patients inhaled, in random order, 40 micrograms ipratropium bromide, 200 micrograms fenoterol hydrobromide, or a combination of 40 micrograms ipratropium and 100 micrograms fenoterol from a powder inhaler, followed by a second dose of the same drug after 60 min. The effects were measured at baseline and 20, 40, 60, and 120 min after the first inhalation. No significant decrease in total respiratory resistance at 8 Hz (Rrs [8]) was observed after ipratropium, whereas Rrs (8) decreased significantly 20 min after fenoterol and 40 min after the combination regimen (p less than 0.05). All three studied drugs resulted in a significant increase in the reactance (p less than 0.01) and decrease in resonant frequency. Both fenoterol (delta FEV1 34 percent, p less than 0.0001) and the combination regimen (delta FEV1 38 percent, p less than 0.0001) resulted in a significantly larger increase in FEV1 than ipratropium alone (delta FEV1 17 percent, p less than 0.0001). A second dose of fenoterol and of the combination regimen resulted in a further significant increase in FEV1 after 120 min (p less than 0.05). A second dose of ipratropium did not result in a further significant increase in FEV1. The changes in respiratory impedance were qualitatively similar for all three drug regimens, but larger in absolute terms after fenoterol and the combination regimen than after ipratropium. The similar effect of these drugs on the reactance can be explained by an increase in the capacitance of the respiratory system, and in combination with a decrease in frequency dependence of resistance, by assuming a decrease in peripheral airway resistance.

Transcutaneous oxygen saturation and carbon dioxide tension during meals in patients with chronic obstructive pulmonary disease

The effect on transcutaneous SaO2 and transcutaneous carbon dioxide tension (PtCO2) of eating was assessed in 44 patients with severe COPD (FEV1 less than 50 percent). The SaO2, PtCO2, and heart rate (HR) were measured every minute before, during, and until 30 minutes after a standardized meal (445 kcal) was consumed. All patients were measured twice on the same day, while eating a meal with high (80 percent) and low (28 percent) carbohydrate content, respectively. The mean meal desaturation (delta SaO2) was less than 1 percent in normoxemic patients but was -3.2 +/- 0.7 percent (p less than 0.001) in hypoxemic (PaO2 less than 7.3 kPa) patients. Significant differences between hypoxemic patients with a delta SaO2 greater than 4 percent and less than or equal to 4 percent, respectively, were found in FEV1 (16 +/- 3 percent and 29 +/- 8 percent; p less than 0.001), respiratory muscle strength (3.9 +/- 1.2 kPa and 5.9 +/- 1.2 kPa; p less than 0.01), HR (112 +/- 12 beats per minute and 90 +/- 18 beats per minute; p less than 0.001), body weight (54.9 +/- 7.5 kg and 74.7 +/- 10.4 kg; p less than 0.001), and fat-free mass (42.0 +/- 6.6 kg and 52.6 +/- 5.8 kg; p less than 0.005) but not in baseline SaO2 and PtCO2. The decrease in SaO2 and the increase in HR were less during the carbohydrate-rich meal. No significant fluctuations in PtCO2 were found after either meal. Meal-related oxygen desaturation cannot explain weight loss in normoxemic patients with COPD but may contribute to a limited dietary intake in a subgroup of hypoxemic patients exhibiting marked oxygen desaturation during meals. A single carbohydrate-rich meal does not have an immediate impact on PtCO2 in stable COPD.

Body composition and exercise performance in patients with chronic obstructive pulmonary disease

To investigate whether a compromised nutritional state may limit exercise performance in patients with chronic obstructive pulmonary disease we studied 54 such patients (FEV1 less than 50% and arterial oxygen tension (PaO2) greater than 7.3 kPa) whose clinical condition was stable and who were admitted to a pulmonary rehabilitation centre. Fat free mass was assessed anthropometrically (from skinfold measurements at four sites) and by bioelectrical impedance; creatinine height index and arm muscle circumference were also assessed. The mean (SD) distance walked in 12 minutes was 845 (178) m. No association was established between the distance walked and spirometric measures. A good correlation was found between the distance walked and fat free mass in the whole group (r = 0.73 for impedance measurements and 0.65 for skinfold thickness) and in a subgroup of 23 lean patients (body weight less than 90% of ideal weight; r = 0.66 for impedance measurements and 0.46 for skinfold thickness). Body weight correlated with the distance walked only in the whole group (r = 0.61). On stepwise regression analysis fat free mass measured by bioelectrical impedance, maximal inspiratory mouth pressure, and PaO2 accounted for 60% of the variation in the distance walked in 12 minutes. We conclude that fat free mass, independently of airflow obstruction, is an important determinant of exercise performance in patients with severe chronic obstructive pulmonary disease.

Energy balance in chronic obstructive pulmonary disease

A substantial number of patients with chronic obstructive pulmonary disease (COPD) suffer from gradual and significant weight loss during the natural course of their illness. The aim of this study was to determine the contribution of resting energy expenditure (REE) and energy intake (E-Intake) to weight loss in 80 patients with stable COPD: age (mean +/- SEM) 65 +/- 3 yr and FEV1 1.0 +/- 0.1 L. A total of 39 patients exhibited a continued weight loss in the previous year. REE measured with a ventilated hood system was significantly (p less than 0.005) higher in weight-losing compared to weight-stable patients when values were normalized for predicted metabolic rate (117 +/- 3 and 108 +/- 2%, respectively) or kg fat-free mass using bioelectrical impedance (FFM-BI): 35.0 +/- 0.8 and 31.8 +/- 0.6 kcal/kg, respectively). Normalized values of E-Intake were not significantly different between weight-losing and weight-stable patients. REE/FFM-BI correlated significantly with FEV1 (r = 0.22, p less than 0.05), maximal inspiratory mouth pressure (Plmax; r = 0.35, p less than 0.001), and E-Intake/FFM-BI (r = 0.48, p less than 0.001). Classification in three subgroups by severity of disease, (1) FEV1 greater than 35%, (2) FEV1 less than or equal to 35%, and (3) PaO2 less than 7.3 kPa, revealed a higher prevalence of weight loss in the more compromised groups and a significantly decreased (p less than 0.05) E-Intake in the hypoxemic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of corridor and treadmill walking in patients with severe chronic obstructive pulmonary disease

The maximal distance walked in a given time period is frequently used as a simple method to evaluate exercise tolerance in patients suffering from chronic obstructive pulmonary disease (COPD). Typically, patients walk on a treadmill or in a corridor at a self-paced speed. Little information is available about the differences between exercise performance in patients with COPD when using the two tests. Therefore, we compared 12-minute corridor walking and 12-minute self-paced treadmill walking in 11 patients with severe COPD. Distances covered in 2, 6, and 12 minutes and walking speeds were significantly higher during corridor walking than during treadmill walking. Heart rate values during the two procedures were not significantly different, and the same degree of breathlessness was found after both walking tests. The study illustrates that corridor walking is a simple and adequate form of exercise testing. Based on heart rate responses, corridor walking appears to be more efficient than treadmill walking, possibly because patients are more familiar with walking in a corridor than on a treadmill. Corridor walking is therefore a useful method to evaluate exercise tolerance and the effects of exercise training programs in patients with COPD.

Forced expiratory flow and oscillometric impedance measurement in evaluating airway obstruction

The application of forced oscillations has been introduced as a noninvasive method to measure the impedance of the respiratory system. Impedance can be partitioned into a real part or resistance and an imaginary part or reactance. The reactance depends on the elastic and inertial properties of the respiratory system. In the present study, resistance and reactance obtained in a frequency spectrum between 4 and 52 Hz were compared with maximal forced expiratory spirometry in 100 out-patients, aged 18-70 years. Resonant frequency and frequency dependence of resistance correlated significantly with selected parameters of the forced expiratory flow volume curve: correlation coefficient values ranged from 0.492 between frequency dependence and FVC and 0.668 between resonant frequency and FEV1. No correlation between average resistance and spirometric parameters reached a statistically significant level. No marked difference was observed between spirometric parameters depending on the early or effort-dependent portion and those parameters depending on the late or effort independent portion of the maximum forced expiration. It can be concluded that each measurement procedure reveals different but characteristic information about the mechanical behaviour and properties of the respiratory system.

Outbreak of multiresistant non-encapsulated Haemophilus influenzae infections in a pulmonary rehabilitation centre

15 out of 21 patients admitted to a pulmonary rehabilitation centre were infected with a non-encapsulated strain of Haemophilus influenzae. All isolates showed identical outer membrane protein patterns, harboured a 40 MD plasmid, produced beta-lactamase, and were resistant to amoxycillin, co-trimoxazole, chloramphenicol, and tetracycline. The strain was first isolated from sputum of another 3 patients in the same hospital ward. 2 of them later introduced it into the rehabilitation centre. The strain spread among the other patients over the next 2 months. The absence of a common iatrogenic source of the organism and its slow spread indicate that the most likely means of transmission was person to person.

Nutritional state and exercise performance in patients with chronic obstructive lung disease

The relation between exercise performance and certain measures of nutritional state was investigated in 83 patients with stable chronic obstructive lung disease (mean age 62 (8) years). All patients had a forced expiratory volume in one second (FEV1) less than 50% predicted, an arterial oxygen tension of more than 7.3 kPa, and no severe locomotor, cardiovascular, neurological, or endocrine disorders. Exercise performance was assessed from a 12 minute walking test; body weight (as a percentage of ideal weight), creatinine height index, and serum concentrations of albumin, transferrin, and prealbumin were assessed as measures of nutritional state. Mean values of the nutritional variables were within the normal range. The mean (SD) 12 minute walking distance was 686 (254) metres. Walking distance was positively associated with serum albumin concentration and creatinine height index but not with body weight, serum prealbumin, or serum transferrin concentrations. When patients were categorised into low, medium and high performance groups on the basis of their walking distance, a very low creatinine height index (mean (SD) 59% (19%] was found in the low performance group. Albumin explained part of the variance in walking distance independently of pulmonary function in a stepwise regression analysis. The findings suggest that in patients with chronic airflow obstruction skeletal muscle mass and serum albumin concentration are positively associated with exercise performance as measured with a 12 minute walk.

Inventory of nutritional status in patients with COPD

Assessment of nutritional status was performed in 153 patients with COPD, admitted to a rehabilitation center. All patients had moderate to severe COPD and were in stable pulmonary condition. Nutritional parameters studied were percentage of ideal body weight, creatinine height index, serum albumin, serum prealbumin, serum transferrin, and total lymphocyte count. A nutritional index composed of four commonly used parameters (PIW, ALB, PALB, TLC) was calculated. This NI was used to separate patients who had a compromised nutritional status (NI greater than or equal to 0.5; 29 patients, 19 percent) from patients who had a normal nutritional status. The results demonstrated a relation between impaired gas exchange and parameters used to assess nutritional status and not between the degree of bronchial obstruction and such parameters.

Localization of bronchial response to ipratropium bromide by respiratory impedance measurement in asthmatics

In 10 asthmatic subjects, the influence of 0.040 mg ipratropium bromide on impedance (Z) of the respiratory system (rs) was determined after cold air challenge. Cold air inhalation caused a significant increase of respiratory resistance (Rrs) at frequencies between 8 and 32 Hz. This increase of Rrs was more pronounced at lower frequencies and, therefore, Rrs became frequency dependent. Respiratory reactance (Xrs) decreased at all frequencies, resulting in an increase of resonant frequency. These changes were compatible with a peripheral airway obstruction and a decrease of airway compliance, according to Mead's analog of the respiratory system. Five min after inhalation of ipratropium bromide, a significant decrease of Rrs between 8 and 28 Hz and a significant increase of Xrs at all frequencies were observed, resulting in a decrease of resonant frequency. Ipratropium bromide significantly reversed the peripheral broncho-constriction induced by cold air challenge.