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Biomedical subjects

L P Malmberg

Publications and source records attributed to L P Malmberg.

16 recordsLinked to original sources
PubMed2001

Tracheal sounds and airflow dynamics in surgically treated unilateral vocal fold paralysis.

The aim of this study was to investigate the changes in tracheal sounds and airflow dynamics in patients who underwent surgical medialization of a unilaterally paralysed vocal fold. Ten adults with unilateral vocal fold paralysis but no history of pulmonary diseases were included. Vocal fold medialization was performed by an injection of autologous fascia into the paralysed vocal fold. Recording of tracheal sounds, flow-volume spirometry and body plethysmography were carried out before and 4-14 months after the operation. The mean number of inspiratory wheezes per respiratory cycle increased from 0.02 (range 0-0.10) to 0.42 (range 0-0.86) and the mean number of expiratory wheezes per respiratory cycle from 0.03 (range 0-0.20) to 0.36 (range 0-0.89). The increment was statistically significant (P=0.03 and P=0.04, respectively). The mean expiratory sound amplitude, in terms of root mean square (RMS), increased from 31.5 dB (range 24.0-38.0) to 34.9 dB (range 25-42) (P=0.03) and the average peak inspiratory flow (PIF) decreased from 4.63 l s-1 (range 2.84-7.51) to 4.03 l s-1 (range 2.27-6.68) (P=0.01). The results indicate that when the paralysed vocal fold is brought into midline by a surgical procedure, the prevalence of inspiratory and expiratory wheezes increases and sound intensity rises. According to this preliminary data tracheal sound analysis gives additional information for the assessment of the subtle changes in the larynx.

Aged↗
PubMed2001

Disturbances in airflow dynamics and tracheal sounds during forced and quiet breathing in subjects with unilateral vocal fold paralysis.

Variable extra thoracic obstruction has been found in spirometric studies in subjects with unilateral vocal fold paralysis. The aim of the study was to further evaluate airflow dynamics in these subjects with body plethysmography and tracheal sound analysis. Ten patients with unilateral vocal fold paralysis without a history of chronic pulmonary diseases and 10 healthy control subjects were studied. Flow-volume spirometry, body plethysmography and tracheal sound analysis were performed within 1 day. The study shows that peak inspiratory flow (PIF) and specific airway conductance (SG(aw)) expressed as percentage of Finnish reference values were significantly lower and airway resistance (R(aw)) was higher among the patients than among the controls (P=0.004, P=0.026 and P=0.004, respectively). The patients had higher sound amplitude of both inspiratory and expiratory tracheal sounds than the controls [root mean square (RMS) values of the power spectra were 31.5 and 25 dB, P=0.006 in inspiration and 31.5 and 26 dB, P=0.013 in expiration, respectively]. Quartile frequencies (F25 and F50) and RMS of expiratory tracheal sounds had significant negative correlation with PIF (P=0.02, P<0.001, P=0.02, respectively) and forced inspiratory volume in 1 s (FIV(1)) (P=0.01, P<0.001, P=0.01, respectively). There was also an association between F50 and peak expiratory flow (PEF) (P=0.02). According to the present study, both quiet breathing and forced inspiration are disturbed in subjects with unilateral vocal fold paralysis. A close relationship between tracheal sounds and respiratory function tests exists.

Aged↗
PubMed2001

Acceptability, reproducibility, and sensitivity of forced expiratory volumes and peak expiratory flow during bronchial challenge testing in asthmatic children.

OBJECTIVES: To compare the acceptability, reproducibility, and sensitivity of spirometric outcome measures of airway caliber during challenge testing in children. DESIGN: FEV(1), forced expiratory volume in 0.75 s, forced expiratory volume in 0.5 s, and peak expiratory flow (PEF) were recorded during stepwise dosimetric histamine challenge tests. The responses were compared, and the reproducibility at baseline and from duplicate measurements at each challenge step was determined. PATIENTS: One hundred five children with newly diagnosed asthma, aged 5 to 10 years. RESULTS: Compared to PEF, FEV(1) showed better baseline reproducibility (p = 0.002) and higher sensitivity (p < 0.0001) during challenge testing, determined as the change normalized to the baseline variation, while the forced expiratory volumes were not significantly different in these respects. During challenge testing in subjects with acceptable flow-volume tracings, paired recordings of FEV(1) agreed within 0.1 L in 85% and within 0.2 L in 93% of measurements. During challenge testing, the reproducibility of FEV(1) measurements was not better than that of the other indexes. Failure to exhale long enough precluded the use of FEV(1) in 16 of the children, particularly the youngest children. CONCLUSIONS: The results demonstrated that the recently published guidelines for FEV(1) measurements during challenge tests can be applied to children. During challenge tests in asthmatic children, the advantage of the shorter fractions of forced expiratory volume was that they were more often acceptably recorded than FEV(1), while they showed as good reproducibility and were also equally sensitive in assessing changes in airway obstruction.

Asthma↗
PubMed2000

Lung function measured by the oscillometric method in prematurely born children with chronic lung disease.

Premature birth is related to a chronic respiratory morbidity, which may persist until school-age. In these children, the forced oscillation technique would be suitable for evaluation of lung function even at preschool age, since it requires only minimal patient cooperation. In order to investigate the oscillometric findings related to premature birth, using the oscillation technique and conventional lung function methods 49 school-aged children born prematurely with (n=15) or without (n=34) chronic lung disease (CLD), and 18 healthy children born at full term were studied. Children with CLD had higher respiratory resistance (Rrs,5) and lower reactance (Xrs,5) than prematurely born children without CLD or healthy controls. Both Rrs,5 (r=-0.55, p<0.0001) and Xrs,5 (r=0.76, p<0.0001) were significantly associated with forced expiratory volume in one second (FEV1), the agreement with spirometry being better in Xrs,5 than in Rrs,5 (p=0.02). Rrs,5 was significantly related to airway resistance (Raw) measured by body plethysmography (r=0.63, p<0.0001), but underestimated resistance at high values of Raw. There was no significant relationship between the pulmonary diffusing capacity and the oscillometric findings. Compared to conventional methods, the oscillometric method yields concordant information on the severity of lung function deficit in children born prematurely, with or without chronic lung disease. In these children, the oscillometric findings are probably due to peripheral or more widespread airway obstruction. As conventional methods are not usually suitable for preschool children, oscillometry may serve as an alternative for early evaluation of chronic lung disease among children with premature birth in clinical or research settings.

Analysis of Variance↗
PubMed2000

Orthostatic increase of respiratory gas exchange in hyperventilation syndrome.

BACKGROUND: Hyperventilation syndrome (HVS) is a common disorder which is difficult to diagnose because of somatic symptoms and its episodic nature. In previous studies respiratory alkalosis in arterial blood was often found during orthostatic tests in patients with HVS. The purpose of this study was to assess these orthostatic changes by non-invasive pulmonary gas exchange measurements and to evaluate whether these responses discriminate patients with HVS from healthy subjects. METHODS: Respiratory gases were collected with a face mask and pulmonary gas exchange was measured after 10 minutes at rest and after eight minutes standing upright in 16 patients with HVS and 13 healthy control subjects. In patients with HVS arterial blood samples were also drawn at rest and in the standing position. RESULTS: At rest the variables of respiratory gas exchange did not differ significantly between the groups. As a response to standing, minute ventilation increased in both study groups but significantly more in the patients with HVS (mean difference 5.4 l/min (95% CI 1.1 to 9.6)). The changes in end tidal CO(2) fraction (FETCO(2)) and in ventilatory equivalents for oxygen (VE/VO(2)) and for CO(2) (VE/VCO(2)) during the orthostatic test were also significantly larger in patients with HVS than in healthy controls. During standing FETCO(2) was significantly lower (mean difference -1.1 kPa; 95% CI -1.5 to -0.6) and VE/VO(2) (mean difference 18.4; 95% CI 7.7 to 29.0) and VE/VCO(2) (mean difference 11.7; 95% CI 4.8 to 18.6) were significantly higher in HVS patients than in healthy controls. By using the cut off level of 4% for FETCO(2) the sensitivity and specificity of the test to discriminate HVS were 87% and 77%, respectively, and by using the cut off level of 37 for VE/VO(2) they were 93% and 100%, respectively. In the HVS patients arterial PCO(2) and FETCO(2) were closely correlated during the orthostatic test (r = 0.93, p<0.0001). CONCLUSIONS: As a response to change in body position from supine to standing, patients with HVS have an accentuated increase in ventilation which distinguishes them from healthy subjects. These findings suggest that non-invasive measurements of pulmonary gas exchange during orthostatic tests are useful in the clinical evaluation of patients with hyperventilation disorders.

Adult↗
PubMed1999

Intraindividual variability of infant whole-body plethysmographic measurements: effects of age and disease.

The intraindividual variability of whole-body plethysmographic measurements was studied in a large series of consecutive infants (N = 144), divided into two groups: a group of infants born very prematurely (PM, N = 63), with (N = 28) or without (N = 35) a history of bronchopulmonary dysplasia (BPD), and a group of infants with persistent respiratory symptoms (PRS, N = 81), i.e., wheezing (N = 53) or cough (N = 28). The intraindividual variability was determined within each test and between tests, separated by a 10-min interval. In both study groups, the between-test variability was significantly larger than that within tests. Expressed as the median coefficient of variation (CV), the between-test repeatabilities in the PRS group were 8.0% for thoracic gas volume (TGV), 17.5% for airway resistance (Raw), and 18.4% for specific airway conductance (sGaw), and in the PM group, 8.9% for TGV, 20.4% for Raw, and 20.7% for sGaw. However, the individual range of CVs was large, ranging from 3 to 19% for TGV and from 5 to 55% for sGaw. With respect to TGV, the difference between the groups was statistically significant (P = 0.03). In infants with a history of BPD, there was also a significant negative age dependency in CVs of sGaw (r = -0.50, P = 0. 009), showing larger variation among younger individuals. The presenting symptom (wheezing or cough) in the PRS group did not influence the measurement variability significantly, and neither did the degree of bronchial obstruction. We conclude that on a group basis, the repeatability of infant body plethysmographic measurements may be satisfactory for scientific studies demonstrating pharmacodynamic effects; however, the intraindividual measurement variability should be reported for each test conditions and for infant groups in each study. Due to the large range in individual variation and the influence of age and disease processes on the variation, for an individual child there is only questionable benefit from a given measurement, unless the intrasubject, between-test variability is assessed individually before interventions, such as a bronchodilation test.

Bronchopulmonary Dysplasia↗
PubMed1999

Metered dose inhaler add-on devices: is the inhaled mass of drug dependent on the size of the infant?

Limited cooperation and low tidal volumes in infants make aerosol therapy difficult. We measured the amount of drug delivered from two baby spacer devices especially developed for use in infants. Designed as a randomized crossover study, aerolized budesonide from a pressurized metered dose inhaler (pMDI) was collected in the inspiratory filter interposed between the face mask and the spacer in 13 infants aged from 2 to 19 months old. The study was performed in connection with pulmonary function testing with a plethysmograph, and the children were sedated with cloral hydrate. Two small-volume baby spacer devices were used: a Babyhaler spacer (GlaxoWellcome, Hertfordshire, UK) made of polycarbonate with a volume of 350 mL and a built-in dead space of 40 mL and a NebuChamber spacer (AstraZeneca, Lund, Sweden) made of stainless steel with a volume of 250 mL and no dead space. Budesonide delivery from the NebuChamber was significantly higher than from the Babyhaler: 38.2% (range, 28.3%-47.5%) of the nominal dose versus 12% (range, 3.3%-21.25%) of the nominal dose of 400 micrograms of budesonide (P = 0.002). The inhaled mass of budesonide from the Babyhaler correlated significantly with skin surface area (r = 0.68, P = 0.018), weight (r = 0.66, P = 0.019), height (r = 0.69; P = 0.017), tidal volume (r = 0.82; P = 0.004), and minute volume (r = 0.67; P = 0.019). No correlations were found between these variables and the inhaled mass of budesonide from the NebuChamber. The results indicate that the design of the NebuChamber spacer affords stable drug delivery in infants and that a large variability in the inhaled mass of drug may be found when infants are inhaling from different baby spacers.

Administration, Inhalation↗
PubMed1998

A new versatile PC-based lung sound analyzer with automatic crackle analysis (HeLSA); repeatability of spectral parameters and sound amplitude in healthy subjects.

A versatile PC-based lung sound analyzer has been developed for short-term recording and analysis of respiratory sounds in research and clinical applications. The system consists of two sound sensors, a flow sensor, a filtering signal amplifier and a PC with a data acquisition card and software for measurement and analysis of the sounds. The analyses include phonopneumography, time expanded waveform analysis, spectral analysis with time averaged Fast Fourier Transform, frequency analysis in time domain (sonogram), and automatic detection and waveform analysis of crackles. Short-term repeatability of spectral parameters of tracheal and lung sounds was studied in 10 healthy subjects. The coefficients of variation (CoV) of the averaged quartile frequencies (F25, F50 and F75) of lung sounds during flow-controlled tidal breathing were 3.7, 4.0 and 8.9% in expiration and 2.7, 3.5 and 4.5% in inspiration, respectively. CoVs of the averaged F25, F50 and F75 of expiratory tracheal sounds were 6.9, 3.0 and 2.4%, and those of inspiratory tracheal sounds 6.3, 2.6 and 3.3%, respectively. Examples of lung sound analysis of samples containing adventitious sounds such as crackles and wheezes are presented. The results indicate that the median frequency has the best repeatability of quartile frequencies of breath sounds and they suggest that the variations of those parameters are low enough for diagnostic purposes. The results also suggest that the analyzer can be a useful new tool for pulmonary research in the fields of physiological and clinical short-term studies of respiratory sounds.

Adult↗
PubMed1996

Classification of lung sounds in patients with asthma, emphysema, fibrosing alveolitis and healthy lungs by using self-organizing maps.

The performance of the self-organizing map (SOM), an artificial neural network, was evaluated in the classification of lung sounds. Patients with asthma (n = 8), emphysema (n = 8) and fibrosing alveolitis (n = 8), and patients with healthy lungs (n = 8) were selected for the study. Fast Fourier transform (FFT) spectra from midinspiratory breath sounds recorded at the right lower lobe area were used to construct feature vectors in the learning and classification process of SOM. The sound segments did not contain wheezing sounds. The lung sounds of 25/32 (78%) patients were classified correctly, with an overall kappa (kappa) value of 0.71. The agreement between the clinical and proposed diagnoses based on classification of lung sounds was good among patients with emphysema (kappa = 0.92) and those with healthy lungs (kappa = 0.83), but only moderate among patients with asthma (kappa = 0.52) and fibrosing alveolitis (kappa = 0.54). This is due to the limitations in distinguishing breath sounds of asthmatics without wheezing sounds from those with crackles in fibrosing alveolitis by the spectral pattern alone. The results indicate that SOM based on FFT spectra is potentially useful in the classification of lung sounds, e.g. in health screening or in differential diagnosis of pulmonary disorders. To enhance the performance of SOM, other features of lung sounds should be combined with FFT spectra.

Adult↗
PubMed1996

Averaged and time-gated spectral analysis of respiratory sounds. Repeatability of spectral parameters in healthy men and in patients with fibrosing alveolitis.

STUDY OBJECTIVE: To obtain a basis for assessment of changes in breath sound spectra in patients with pulmonary diseases, short-term and day-to-day repeatability of spectral parameters was studied. DESIGN: Breath sounds were recorded simultaneously from the trachea and from the chest twice at an interval of 15 min (short-term repeatability) and of 1 to 3 days (day-to-day repeatability). During recordings, air flow at the mouth was controlled, the target inspiratory and expiratory peak flow being 1.25 L/s. Inspiratory and expiratory breath sound spectra were averaged over 7 to 10 successive respiratory cycles. The repeatability of sound intensity (RMS), frequency of maximum intensity (Fmax), and median frequency (F50) was analyzed with analysis of variance. PARTICIPANTS: Short-term repeatability was studied in 10 healthy nonsmoking men (age 25 to 44 years), and day-to-day repeatability was studied in 10 healthy nonsmoking men (age 23 to 41 years) and in 12 patients with clinically stable fibrosing alveolitis (age 35 to 82 years). RESULTS: Short-term coefficient of variation (CoV) of Fmax and F50 was 2.6 to 6.7% when recorded from the chest, and 6.2 to 8.7% when recorded from the trachea. Day-to-day CoV of Fmax and F50 in healthy subjects was 4.7 to 8.5% and 5.0 to 8.7% recorded from the chest or from the trachea, respectively. Inspiratory day-to-day variation in those parameters was higher in patients with fibrosing alveolitis. CoV of RMS was high, ranging from 18 to 47% in different subject groups and sampling situations. CONCLUSIONS: Repeatability of F50 of averaged flow-controlled lung sound spectra is good both in healthy subjects and in patients with fibrosing alveolitis. Thus, F50 of respiratory sound spectra may be useful in monitoring of changes induced by respiratory diseases and interventions. These results emphasize the importance of standardization of recording conditions and of analyzing techniques.

Adult↗
PubMed1995

Significant differences in flow standardised breath sound spectra in patients with chronic obstructive pulmonary disease, stable asthma, and healthy lungs.

BACKGROUND: Spectral characteristics of breath sounds in asthma and chronic obstructive pulmonary disease (COPD) have not previously been compared, although the structural differences in these disorders might be reflected in breath sounds. METHODS: Flow standardised inspiratory breath sounds in patients with COPD (n = 17) and stable asthma (n = 10) with significant airways obstruction and in control patients without any respiratory disorders (n = 11) were compared in terms of estimates of the power spectrum. Breath sounds were recorded simultaneously at the chest and at the trachea. RESULTS: The median frequency (F50) of the mean (SD) breath sound spectra recorded at the chest was higher in asthmatics (239 (19) Hz) than in both the control patients (206 (14) Hz) and the patients with COPD (201 (21) Hz). The total spectral power of breath sounds recorded at the chest in terms of root mean square (RMS) was higher in asthmatics than in patients with COPD. In patients with COPD the spectral parameters were not statistically different from those of control patients. The F50 recorded at the trachea in the asthmatics was significantly related to forced expiratory volume in one second (FEV1) (r = -0.77), but this was not seen in the other groups. CONCLUSIONS: The observed differences in frequency content of breath sounds in patients with asthma and COPD may reflect altered sound generation or transmission due to structural changes of the bronchi and the surrounding lung tissue in these diseases. Spectral analysis of breath sounds may provide a new non-invasive method for differential diagnosis of obstructive pulmonary diseases.

Adult↗
PubMed1994

Frequency distribution of breath sounds as an indicator of bronchoconstriction during histamine challenge test in asthmatic children.

In order to study changes in respiratory sounds associated with acute bronchoconstriction and -dilatation, breath sounds of 11 children with asthma (age range, 10-14 years) were recorded at the chest and at the trachea during histamine challenge test and after subsequent bronchodilatation. The changes in frequency spectra of breath sounds were compared with simultaneous changes in forced expiratory volume in 1 second (FEV1). In seven children who responded to histamine with a decrease in FEV1 of more than 15%, there was a significant relationship between percentage change in FEV1 (delta FEV1) and percentage change in median frequency (delta F50) of expiratory breath sounds recorded at the chest (r = 0.865; beta = -0.706, P = 0.0001) and at the trachea (r = 0.888; beta = -1.12, P = 0.0001). The association between breath sound intensity and FEV1 was weaker. Based on ANOVA, the increase of F50 during the challenge test was significantly larger in children who responded to histamine than in those who were non-responsive (P = 0.0016). At the chest, a decrease of 15% in FEV1 corresponded to an increase of 8% in expiratory F50. The provocative dose of histamine inducing a decrease of 15% in FEV1 (PD15FEV1) and the provocative dose causing an increase of 8% in F50 (PD8F50) were significantly related (r = 0.927, P = 0.003). We conclude that spectral analysis of breath sounds can be used to indicate airway obstruction during bronchial challenge tests in children, and may be adapted for tests in pre-school children. The results suggest that the same mechanisms that induce airflow limitation due to inhaled histamine may generate an increase in frequency content of breath sounds in children with asthma.

Adolescent↗
PubMed1994

Changes in frequency spectra of breath sounds during histamine challenge test in adult asthmatics and healthy control subjects.

Air-flow standardized breath sounds were recorded at the chest and at the trachea during histamine challenge test and after subsequent bronchodilation in 12 asthmatics and 6 healthy controls for spectral analysis, to be compared with simultaneous changes in spirometric variables. Of all the lung sound variables measured, the changes in median frequency of the power spectrum (F50) of tracheal expiratory sounds were found to correlate best (r = 0.853, p < 0.0001) with changes in FEV1. The increase of F50 during histamine challenge was significantly larger in asthmatics than in healthy control subjects (p < 0.005). The provocative dose of histamine inducing a decrease of 15 percent in FEV1 (PD15FEV1) and the provocative dose causing an increase of 30 percent in tracheal expiratory F50 (PD30F50) were significantly related (r = 0.754, p = 0.012). In asthmatics, the breath sound frequency distribution in terms of median frequency reflected acute changes in airways obstruction with high sensitivity and specificity. The present method for breath sound analysis can be applied for patients with limited cooperation during bronchial challenge tests.

Adolescent↗
PubMed1993

Accuracy and repeatability of a pocket turbine spirometer: comparison with a rolling seal flow-volume spirometer.

The accuracy and repeatability of a recently introduced pocket spirometer (Micro Spirometer; Micro Medical Instruments Ltd, Rochester, UK) was evaluated. FEV1 and FVC values obtained with this instrument were compared with those measured with a rolling-seal flow-volume spirometer (CPI 220 with microcomputer) in 31 patients and 11 healthy volunteers. In the whole material, expressed as mean +/- SD, the pocket spirometer recorded 0.44 +/- 0.23 l (13 +/- 7%) smaller values for FEV1 (P < 0.001) and 0.64 +/- 0.48 l (15 +/- 11%) smaller values for FVC (P < 0.001) than the rolling-seal spirometer. The short-term repeatability of the measurements expressed as the coefficient of variation of repeated measurements using the pocket spirometer was 2.2% for FEV1 and 2.3% for FVC in a series of 10 healthy subjects and 10 patients with COPD. It is concluded that the underestimation of FEV1 and FVC of the pocket spirometer was too large and inconsistent for the device to be used interchangeably with conventional spirometers. However, the repeatability of the measurements with the pocket spirometer is close to that reported previously for flow-volume spirometry. Thus the pocket spirometer may be suitable in assessing acute changes of spirometric indices e.g. during provocation tests or during patient follow-up in asthma.

Adolescent↗
PubMed1993

A rapid dosimetric method with controlled tidal breathing for histamine challenge. Repeatability and distribution of bronchial reactivity in a clinical material.

A rapid dosimetric method with controlled tidal breathing for histamine challenge was evaluated by assessment of its repeatability, by comparing to a present nondosimetric standard method, and by application to adult patients with recent asthma (n = 31), chronic asthma (n = 33), chronic cough (n = 71) or chronic rhinitis (n = 41) and to healthy controls (n = 31). An automatic inhalation-synchronized dosimetric jet nebulizer with a known lung deposition of the aerosol was used to administer histamine and to control breathing. The non-cumulative doses of histamine diphosphate were 0.025, 0.1, 0.4 and 1.6 mg, administered during 0.4 s following tidal inspiration of 100 ml of air. The test procedure required 1 inhalation of histamine 4 mg/ml and followed by 1, 4 and 16 inhalations of histamine 16 mg/ml from the device, and its duration was about 30 minutes. The intraindividual correlation coefficient of the histamine dose causing a reduction of 15 percent in FEV1 (PD15FEV1) on 2 consecutive days in 14 asthmatic subjects was 0.937; the standard error of the single determination was 13 percent of the mean PD15 FEV1. A PD15FEV1 value below 0.4 mg was found only in asthmatic subjects; in chronic asthma, below 0.5 mg; in recent asthma, between 0.1 mg and 1.6 mg or more. In patients with chronic cough and chronic rhinitis, 20 and 32 percent, respectively, the PD15FEV1 values between 0.4 and 1.6 mg, the other patients in these groups were non-responsive. In all healthy control subjects, the PD15FEV1 was over 1.0 mg, 80 percent of them were nonresponsive to the maximum 1.6 mg dose. This new test allows rapid, accurate, and quantitative assessment of bronchial responsiveness to histamine.

Adult↗