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Biomedical subjects

H Pasterkamp

Publications and source records attributed to H Pasterkamp.

At least 37 records · Page 2Linked to original sources
PubMed1993

Wheezing and airflow obstruction during methacholine challenge in children with cystic fibrosis and in normal children.

To study wheeze as an indicator of bronchial responses during standardized methacholine challenge (MCH), we used computerized analysis of respiratory sounds in children with cystic fibrosis (CF) and in healthy control subjects. We recorded tracheal and lung sounds from 10 young CF = yCF patients, mean age 5.7 yr (range 4 to 7 yr), 13 older CF = oCF, age 10.5 yr (8 to 18 yr), 7 young normal subjects = yNO, age 5.3 yr (4 to 7 yr), and 11 older normal subjects = oNO, age 11 yr (8 to 16 yr). Spirometry was obtained after each doubling concentration of methacholine until the concentration provoking a > or = 20% fall in FEV1 (PC20) or the end point (8 mg/ml) was reached. Sound and calibrated flow signals were recorded on tape and later analyzed by respirosonography. The concentration of methacholine associated with wheeze (PCw) was noted. Wheezing was quantified by its duration during inspiration (Tw/TI) and expiration (TW/TE). We found a positive response to MCH in 11 of 13 oCF (PC20 0.75 mg/ml, range 0.08 to 3.0) and in 3 of 11 oNO (PC20 4.2 mg/ml, range 2.5 to 6.5). Wheezing occurred in 6 oCF (PC20 < 8 mg/ml). In 7 yCF PC20 or PCW developed (1.51 mg/ml, range 0.125 to 4.0) versus 4 yNO (4.0 mg/ml, range 2.0 to 8.0). In 10 oCF subjects who performed MCH on three occasions within a 2-wk period, both positive and negative wheeze responses were reproducible. Patients who wheezed had a lower FRC compared with patients who did not (109 versus 147% of predicted, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Tracheal sound spectra depend on body height.

Tracheal sounds originate from turbulent flow in upper and central airways. Turbulent flow characteristics are influenced by conduit dimensions. Because tracheal dimensions are a function of body height, we hypothesized that there should be a correlation between sound spectra and body length. We recorded tracheal sounds at standardized airflows in 21 healthy children 9.1 +/- 0.6 yr of age (mean +/- SE) and in 24 healthy adults 30.2 +/- 0.8 yr of age. A contact sensor was attached at the suprasternal notch of the sitting subject, and airflow was measured at the mouth with a calibrated pneumotachograph. Tracheal sounds were low-pass-filtered at 2.4 kHz and digitized at 10 kHz. A 2048 point FFT was applied at a successive 100-ms intervals, using a Hanning data window. Resulting spectra were normalized to a reference power of 0.1 (mV)2/5 Hz. We applied a gating algorithm to extract sounds at inspiratory flows of 1 L/s (+/- 10% tolerance), and we computed average power spectra from the collected samples. We calculated the average spectral power (Pavg), the quartile frequencies below which 25% (Q1), 50% (Q2), and 75% (Q3) of the power in the range of 50 to 2,000 Hz was contained, the spectral edge frequency (SE95) below which 95% of the power was found, and the frequency where spectral power rolled off sharply (Fcut).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Measurement of respiratory acoustical signals. Comparison of sensors.

We assessed the performance of three air-coupled and four contact sensors under standardized conditions of lung sound recording. Recordings were obtained from three of the investigators at the best site on the posterior lower chest as determined by auscultation. Lung sounds were band-pass filtered between 100 and 2,000 Hz and sampled simultaneously with calibrated airflow at a rate of 10 kHz. Fourier techniques were used for power spectral analysis. Average spectra for inspiratory sounds at flows of 2 +/- 0.5 L/s were referenced against background noise at zero flow. Air-coupled and contact sensors had comparable maximum signal-to-noise ratios and gave similar values for most spectral parameters. Unexpectedly, less sensitivity (lower signal-to-noise ratio) at high frequencies was observed in the air-coupled devices. Sensor performance needs to be characterized in studies of lung sounds. We suggest that lung sound spectra should be averaged at known airflows over several breaths and that all measurements should be reported relative to sounds recorded at zero flow.

Adult↗
PubMed1992

Tracheal sounds in upper airway obstruction.

A boy with subglottic narrowing secondary to laryngotracheitis presented with noisy breathing. Acoustic measurements of tracheal sounds at standardized air flows correlated well with the clinical course and with spirometric assessments. This indicates the potential value of respiratory sound characterization in patients with upper airway obstruction.

Child↗
PubMed1991

Respirosonography in infants with acute bronchiolitis.

Respirosonography was used to analyze lung sounds and breathing patterns in 16 infants with acute bronchiolitis who were treated with nebulized salbutamol (albuterol). Wheezing was measured as a proportion of respiratory time (time spent wheezing [Tw]/total time [Ttot]). A decrease of 10% or greater in Tw/Ttot or a reduction in Tw/Ttot to less than 2% was considered a positive response to salbutamol. Seven infants responded to the salbutamol, and nine did not. In responders, Tw/Ttot decreased from 47% +/- 26% to 20% +/- 25% (mean +/- SD), and the respiratory rate decreased from 65 +/- 8 to 57 +/- 7 breaths per minute. In nonresponders, mean Tw/Ttot either did not change or increased, and there was no significant change in respiratory rate (53 +/- 10 breaths per minute before salbutamol inhalation and 56 +/- 9 breaths per minute after salbutamol inhalation). Complex repetitive waveforms, different from the sinusoidal waveforms of typical wheezing, were observed in 14 of 16 infants. Our findings add supportive evidence to the clinical impression that some infants with bronchiolitis respond to salbutamol. Respirosonography provides a noninvasive method for objective clinical assessment of young, wheezy children.

Acoustics↗
PubMed1991

Relationship between response to inhaled salbutamol and methacholine bronchial provocation in children with suspected asthma.

Fifty children (27 females, 23 males) ages 6-15 years who were referred for evaluation of suspected asthma had baseline FEV1 and FEF25-75 of greater than or equal to 80% and FEF50 greater than or equal to 70% of predicted values. All had these tests repeated on the same day, after inhaling salbutamol. On a subsequent day PC-20 (methacholine) was determined as an index of bronchial hyperreactivity (BH). Fourteen age-matched healthy children (6 females, 8 males) were studied in a similar manner. There was no significant relationship between the PC20 and the change in FEF25-75 or FEF50 following salbutamol. There was a negative correlation between the initial FEV1 (% predicted) and the percent change in FEV1 following salbutamol (P less than 0.01). An increase in FEV1 of greater than 6% occurred in 7/12 (58.3%) patients with PC20 less than or equal to 0.25 mg/mL (Group I); in 7/24 (29.2%) patients with PC20 = 0.26-2.0 mg/mL (Group II); in only 1/14 (7.1%) patients with PC20 greater than 2.1 mg/mL (Group III) and in none of those asymptomatic (control) children with PC20 greater than 8.0 mg/mL (Group IV). All subjects who had a change in FEV1 greater than 6% after salbutamol had a PC20 less than 8 mg/mL and this test detected the majority of patients with severe BH. However, although the sensitivity of the test was 100%, the predictive value was only 36%. We conclude that in the presence of a normal baseline FEV1 a change of greater than 6% following salbutamol inhalation is indicative of bronchial hyperreactivity.

Administration, Inhalation↗
PubMed1991

Sleep quality in children with asthma treated with theophylline or cromolyn sodium.

The effect of theophylline and cromolyn sodium on sleep was studied in 10 children with asthma who were 10 to 17 years of age (mean 13.5 +/- 2.4 years). Theophylline or cromolyn sodium was taken for 14 days in a double-blind, crossover, placebo-controlled trial. Theophylline blood levels before sleep were 10.2 +/- 4 micrograms/ml during the theophylline period. There was no difference in pulmonary function between the two periods. Theophylline did not disrupt sleep as measured by sleep latency, total sleep time, sleep efficiency, movement time, microarousals, and arousals. Apneic episodes (greater than or equal to 10 seconds) were of central origin and less frequent during the theophylline period (p less than 0.05). Arterial oxygen desaturation (greater than 5% decrease from baseline saturation when awake) was less frequent during the theophylline treatment (p less than 0.05). We conclude that theophylline treatment of the children's asthma did not disrupt sleep and appeared to have a protective effect in regard to apnea, hypopnea, and arterial oxygen saturation.

Adolescent↗
PubMed1989

Home measurement of oxygen saturation during sleep in patients with cystic fibrosis.

Feasibility and reproducibility of home measurement of arterial oxygen saturation (SaO2) were evaluated in 14 clinically stable patients with cystic fibrosis (CF). Changes in SaO2 during sleep were compared to the clinical status and pulmonary function while awake to identify predictors of nocturnal oxyhemoglobin desaturation. Each patient was assessed by clinical score, spirometry, and arterial blood gas analysis within 72 hours of the overnight study. Eight patients were studied on more than one occasion to assess dependence of SaO2 on position and reproducibility of overnight studies. A pulse oximeter stored up to 8 hours of nocturnal SaO2 measurements in its memory. Off-line analysis of trend data provided the proportion of sleep with SaO2 less than 90% and less than 85%. We found that patients with daytime PaO2 less than 60 mm Hg spent greater than 80% of their sleep with SaO2 less than 90%, while those with PaO2 greater than 70 mm Hg spent less than 20% of the night with SaO2 less than 90%. Patients with daytime PaO2 of 67-70 mm Hg were desaturated to less than 90%, from 0 to 98% of the night. No consistent body position dependence of daytime SaO2 was found. Home measurement of SaO2 during sleep was reproducible, with a difference on two repeat occasions of 4% +/- 2 (mean +/- SEM) for %time with SaO2 less than 90% and 3% +/- 2 for %time with SaO2 less than 85%. The severity of hemoglobin desaturation during sleep could not be reliably predicted from clinical scores or awake pulmonary function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Obstructive sleep apnea leading to increased intracranial pressure in a patient with hydrocephalus and syringomyelia.

Rises in intracranial pressure from normal baseline values up to 50 cm H2O occurred shortly after the onset of obstructive sleep apnea in a patient with myelomeningocele, hydrocephalus, Arnold-Chiari malformation, and syringomyelia. Tonsillar hypertrophy caused the airway obstruction during sleep, because the obstructive sleep apnea and also the periodic elevation of intracranial pressure disappeared after tonsillectomy. Only one report from Japan has previously described three patients with elevated cerebrospinal fluid pressures during obstructive sleep apnea. It is conceivable that episodic airway obstruction and concurrent intracranial hypertension may have contributed to the development of syringomyelia in our patient.

Adolescent↗
PubMed1989

Digital respirosonography. New images of lung sounds.

We used tape recordings from normal subjects and from patients with lung disease to generate spectrographic images of respiratory sounds on a personal computer. These digital respirosonograms presented timing and frequency content of lung sounds, with the sound intensities displayed on a color scale. Respiratory sounds during inspiration and expiration could be recognized by their association with concurrent respiration curves. Contributions of low-frequency cardiac sounds were visually identified by their relationship to simultaneously recorded ECGs. Typical characteristics of normal and adventitious lung sounds were documented and displayed both in the time and the frequency domain. Digital respirosonography provides an easy way to assess lung sound amplitudes, frequencies and timing over several breaths.

Adolescent↗
PubMed1988

Effect of terfenadine on the response to exercise and cold air in asthma.

To assess the role of histamine as a mediator in the response to exercise and isocapnic hyperventilation of cold air (IHCA) in asthma, we studied nine asthmatic subjects, age 13 to 25 years. All had exercise induced asthma (EIA) and positive responses to IHCA. Baseline lung function was measured before standardized challenges with histamine, exercise and IHCA. On separate days, these tests were repeated 3 h after a single oral dose of 120 mg terfenadine (TF). Histamine responsiveness decreased significantly, with a provocative concentration, producing a greater than or equal to 20% fall in FEV1 (PC20), of 1.1 +/- 0.8 mg/ml (mean +/- SEM) before and 12.0 +/- 4.9 mg/ml after the antihistamine. EIA was significantly less after TF, with 53 +/- 5% mean maximal falls in FEV1 from baseline before, and 29 +/- 9% after treatment (P less than 0.01, paired t-test). In contrast, the effect of TF on the response to IHCA was insignificant, with mean maximal falls of 45 +/- 7% in FEV1 before, and 41 +/- 7% after treatment. There was a correlation between PC20 and lowest FEV1 (% predicted) for EIA (r = 0.56, P less than 0.05), but not for IHCA (r = 0.34, NS). This study indicates a role of histamine as a mediator in EIA but not in IHCA, supporting different mechanisms for both stimuli.

Adolescent↗
PubMed1988

The use of a personal computer for trend data analysis with the Ohmeda 3700 pulse oximeter.

The Ohmeda 3700 pulse oximeter provides trend data storage of arterial oxygen saturation (SaO2) and pulse rate measurements for a maximum of 8 hours. This feature allows the oximeter to be used as a stand-alone unit for overnight studies of saturation during sleep. Subsequent transfer and processing of the stored SaO2 data requires additional software. We present a program for data processing that uses the Lotus 1-2-3 program on IBM and compatible microcomputers and that performs a data distribution and statistical analysis on these trend data and presents them in graphic form. Processing SaO2 trend data within the Lotus 1-2-3 worksheet format allows the user to easily add to or modify the program presented here, depending on individual needs.

Adult↗
PubMed1987

Subjective assessment vs computer analysis of wheezing in asthma.

To determine if wheezing is a reproducible clinical sign, we presented recorded breath sounds from asthmatic patients to four groups of health professionals: pediatric residents, nurses, pediatricians, and physiotherapists. Their subjective assessments included scores of wheezing severity and estimates of wheezing duration. All participants repeated the test at least two weeks later. Results were compared to computer aided spectral analysis of the recorded breath sounds. Interobserver and intraobserver variability fell somewhat between chance and total agreement. In contrast, the computer analysis allowed an objective and reproducible characterization of wheezing in asthma.

Adult↗
PubMed1987

Nomenclature used by health care professionals to describe breath sounds in asthma.

We studied the spontaneous, uninstructed description by 40 health care professionals of breath sounds in asthmatic patients, and their use of lung sound terminology following current recommendations. Tape play-back auscultation of recorded tracheal and lung sounds was performed by ten observers in each group of residents, nurses, staff physicians and physiotherapists. They repeated the test after two weeks to three months. Individual descriptions were compared to computer-aided characterization of the breath sound recordings. We found significant differences in the preferred terms for description of adventitious lung sounds between the groups of health care professionals. There was considerable intraobserver variability, with less agreement when suggestions for a more complex characterization were followed. Our observations indicate the importance of teaching a standardized nomenclature for lung sounds to health care professionals, using only terms which are clearly informative of pulmonary disease.

Allied Health Personnel↗
PubMed1986

Relationship between respiratory muscle strength, nutritional status, and lung volume in cystic fibrosis and asthma.

We measured static inspiratory and expiratory pressures (PImax and PEmax) in 29 patients with asthma for comparison with a previously reported group of 25 patients with cystic fibrosis (CF) and 80 normal control subjects. The purpose of the study was to assess the relationship between respiratory muscle strength, nutritional status, lung volumes, and training effect of the increased work of breathing in patients with chronic air-flow limitation. PEmax was similar in the asthma group, CF group, and normal control subjects despite a significant degree of malnutrition in the CF group (mean body mass percentile (BMP), 78 versus 107% in the asthma group, p less than 0.001). There was no correlation between BMP and PImax or PEmax in either study group. PImax, when corrected for lung volume, was greater than age- and sex-matched control values in 24% of the patients with CF and 48% of the patients with asthma. We conclude that respiratory muscle strength is not related to nutritional status (as measured by BMP) in patients with CF and asthma. Above-normal inspiratory muscle strength may result from a training effect of the increased work of breathing in both CF and asthma, regardless of nutritional status.

Adolescent↗