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Biomedical subjects

M A Sackner

Publications and source records attributed to M A Sackner.

At least 73 records · Page 4Linked to original sources
PubMed1984

Mechanism of bronchoconstrictive effects of aerosolized buffered saline in asthmatics.

Bronchoconstriction, measured by spirometry and body plethysmography, has been reported with deep breaths of air and of aerosolized buffered saline (ABS) (0.5% sodium chloride and phosphate buffer), in some stable asthmatics. To investigate the mechanisms of this phenomenon, we measured airway resistance (Raw) and functional residual capacity (FRC) in ten asthmatics after deep breaths of ABS, tidal breaths of ABS, tidal breaths of unbuffered normal saline (0.9% sodium chloride) and tidal breaths of 0.5% sodium chloride (ABS without phosphate) on different days. Raw and FRC increased with deep breaths and tidal breaths of ABS in all asthmatics, but not with tidal breaths of normal saline and unbuffered 0.5% sodium chloride. Thus the phosphate buffer rather than the hypoosmolarity of aerosolized buffered saline causes bronchoconstriction in asthmatics.

Adult↗
PubMed1984

Breathing pattern alterations with aerosolized buffered saline--effects of topical airway anesthesia.

Bronchoconstriction, measured by spirometry and body plethysmography, may occur with inhalation of aerosolized buffered saline (ABS) (0.5% sodium chloride and phosphate buffer) in asymptomatic patients with bronchial asthma. To estimate the prevalence and mechanism of this phenomenon, we employed continuous non-invasive monitoring of the breathing pattern to estimate changes of end-expiratory level, minute ventilation and mean inspiratory flow, which may be more sensitive albeit less specific indicators of bronchoconstriction. We studied normal and asymptomatic asthmatic subjects before and after ABS inhalation. Deep breaths of ABS had no effect on the breathing pattern in normals, but in all of the asthmatics increases of end-expiratory level, minute ventilation, tidal volume and mean inspiratory flow lasted at least 15 minutes. On another day, prior topical airway anesthesia in the asthmatic subjects prevented the changes in breathing pattern after ABS inhalation. Thus analysis of the breathing pattern suggests that bronchoconstriction or irritation of vagal airway receptors after inhalation of aerosolized buffered saline occurs to a high degree in asymptomatic asthmatic subjects because changes in breathing pattern are prevented by prior airway anesthesia which probably inactivates vagal afferent pathways.

Adult↗
PubMed1984

Pulmonary function in sarcoidosis.

Pulmonary function testing provides an important insight into the pathophysiology in patients with sarcoidosis. Major functional abnormalities in this disease include decreased diffusing capacity, lung compliance and lung volumes. Arterial oxygen desaturation with exercise is common. Airways obstruction may occur as an isolated finding or be superimposed on the interstitial process. The activity of the disease cannot be well determined by pulmonary function tests but serials testing is helpful in detecting progression or improvement.

Airway Resistance↗
PubMed1983

Aerosol rebreathing method for assessment of airway abnormalities: theoretical analysis and validation.

An aerosol rebreathing method which determines total aerosol deposition in the lung by rebreathing non-radioactive inert aerosol was investigated theoretically for its performance characteristics. The method was then validated experimentally by examining a system response to various operating parameters, its reproducibility and convenience in clinical use. It was found from the theoretical analysis that an optimum performance would be achieved by breathing an aerosol of particles 1 micrometer in diameter with a 500-cm3 tidal volume at the breathing rate of 30 breaths/min. With these optimum parameters, experimental results of 10 normals and 10 patients with obstructive airway disease revealed an excellent measurement reproducibility within subjects (+/- 10% from means). There was a wide separation between the two groups in terms of number of rebreathing breaths to reach 90% aerosol deposition (N90) (mean +/- S.E. = 10.8 +/- 1.6 for normals vs. 3.9 +/- 1.1 for patients) and cumulative percentage of aerosol deposition at the fourth breath (AD4) (mean +/- S.E. = 68 +/- 4.4% for normals vs. 90 +/- 3.5% for patients).

Adult↗
PubMed1983

Effect of positive end-expiratory pressure on breathing patterns of normal subjects and intubated patients with respiratory failure.

The aims of this study included assessment of accuracy of respiratory inductive plethysmography when pulmonary hyperinflation was induced by application of PEEP, and examination of breathing patterns of normal subjects, intubated patients requiring mechanical ventilation and intubated patients immediately before extubation during application of PEEP by demand valve and high gas flow reservoir bag systems. Validation of tidal volume (VT) and end-expiratory level measured with respiratory inductive plethysmography to simultaneous spirometry (SP) was achieved with PEEP levels up to 12.5 cm H2O in 7 normals. In 17 intubated patients, almost all VT values measured with respiratory inductive plethysmography fell within +/- 10% of SP even with 2 to 3 changes of body posture. In normal subjects, increasing levels of PEEP from the demand valve system produced nonprogressive rises of VT and mean inspiratory flow, falls of frequency and fractional inspiratory time (TI/TTOT), and no changes of minute ventilation (Vmin) nor mean expiratory flow. PEEP from the high gas flow reservoir bag system produced nonprogressive rises of VT and rib cage (RC) contribution to VT, and rises of Vmin and mean inspiratory and expiratory flows between 10.0 and 12.5 cm H2O of PEEP. Intubated patients requiring intermittent mandatory ventilation (IMV) had a rapid, shallow breathing pattern unaltered by PEEP levels delivered by either system up to 12.5 cm H2O despite increases of end-expiratory level. Intubated patients who were about to be extubated breathed with patterns closer to ambulatory normal subjects with the exception of their elevated RC contribution to VT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Deposition of aerosol particles and flow resistance in mathematical and experimental airway models.

Aerosol deposition and flow resistance in obstructed airways were determined from five mathematical and experimental airway models. The first three models were theoretical and based upon Weibel's symmetrical lung model with 1) uniform reduction of airway diameter in various groups of airway generations; 2) obstruction of a few major airways such that a severe uneven flow distribution occurs in the lung; 3) focal constriction of selected large airways. In model 3, an empirical formula was utilized to assess deposition and resistance in the constricted airways. The remaining two models were tested experimentally; 4) oscillation of a compliant wall in a straight tube and 5) two-phase gas-liquid flow utilizing human sputum in a rigid branching tube. In models 1, 2, and 3, airway resistance increased to a greater extent than did the increase of aerosol deposition except when small airways were obstructed in model 1. Here, the increase of aerosol deposition was slightly higher than the rise in airway resistance. A sharp increase of aerosol deposition with a minimal increase of flow resistance was demonstrated in models 4 and 5. These data indicate that aerosol deposition may be a more sensitive indicator of airway abnormalities than overall airway resistance in small airways obstruction, during oscillation of large and medium airway walls, and when excessive secretions within the airways move with a wave or slug motion.

Aerosols↗
PubMed1983

Effect of naloxone on breathing pattern in patients with chronic obstructive pulmonary disease with and without hypercapnia.

Recent reports suggest that endogenously released endorphins may exert a modifying influence on respiratory center drive in patients with respiratory disease. In this report, we employed respiratory inductive plethysmography to noninvasively assess breathing patterns with particular attention to respiratory center drive as reflected by mean inspiratory flow. We studied 10 patients with documented chronic obstructive pulmonary disease (6 with hypercapnia and 4 with normocapnia) after treatment with placebo and the opiate antagonist, naloxone. No significant change in breathing pattern was observed in either patient group after treatment with placebo or naloxone, although individual patients displayed greater respiratory drive after naloxone than placebo. Therefore, endorphins do not exert a consistent influence on respiratory center output in patients with chronic obstructive pulmonary disease.

Aged↗
PubMed1983

Validation of respiratory inductive plethysmography in patients with pulmonary disease.

The assumption that the respiratory system behaves with 2 df of motion in healthy persons allows calibration of respiratory inductive plethysmography (RIP) with spirometry (SP). To ascertain whether RIP could be calibrated by the same assumption in patients with lung disease, even though at least 3 df of motion are visualized (ie, upper and lower rib cage and upper and lower abdomen move out of phase), RIP was calibrated by a two-position calibration procedure and validated satisfactorily by simultaneous SP in the erect, semirecumbent, supine, and lateral decubitus positions. In lung disease, the contribution to tidal volume of regions moving independently of the combined rib cage and abdominal movements either is small or remains relatively constant with change of body posture. For clinical monitoring of the resting breathing pattern where patient movements cannot be restricted, respiratory inductive plethysmography can serve as a reliable semiquantitative, noninvasive ventilatory monitoring device.

Abdomen↗
PubMed1983

Breathing patterns. 1. Normal subjects.

Ventilatory monitoring devices that require mouthpiece breathing produce a rise in tidal volume (VT), a fall in frequency (f) and alterations in periodicity and variability of breathing components. Together with the introduction of the respiratory inductive plethysmograph, a reliable noninvasive monitoring device of ventilation, major advances have taken place in understanding the significance of the components of the breathing pattern. We measured the breathing pattern of normal subjects utilizing respiratory inductive plethysmography and continuously processed these data with a microprocessor system. The mean values of the breathing pattern components in normal subjects were not affected by age, but the rhythmicity was more irregular in the elderly. The values of breathing pattern components obtained noninvasively by respiratory inductive plethysmography in normal subjects are fairly predictable in limits similar to other tests of pulmonary function.

Adult↗
PubMed1983

Breathing patterns. 2. Diseased subjects.

We measured the breathing pattern of normal subjects, asymptomatic smokers, asymptomatic and symptomatic asthmatic patients, and patients with chronic obstructive pulmonary disease, restrictive lung disease, primary pulmonary hypertension and anxiety state utilizing respiratory inductive plethysmography. Respiratory rate was increased above the normal in smokers and in patients with COPD, restrictive lung disease and pulmonary hypertension, but remained normal in asthmatic patients. Inspiratory times (T1) of one second or less often occurred in patients with COPD, restrictive lung disease, and pulmonary hypertension. Smokers and patients with symptomatic asthma, COPD, restrictive lung disease and pulmonary hypertension showed heightened respiratory center drive as reflected by elevated mean inspiratory flow (VT/TI). Fractional inspiratory time was reduced to a variable extent in smokers, symptomatic asthmatic patients and patients with COPD, and was a weak indicator of airways obstruction. Patients with COPD often had major fluctuations of expiratory timing, periodic fluctuations of end-expiratory level, and asynchrony between rib cage and abdominal movements. Chronic anxiety was characterized by frequent sighs; episodic rapid rates alternating with apneas were less common. We conclude that analysis of breathing patterns provides diagnostic discrimination among normal subjects and disease states.

Adult↗
PubMed1983

Breathing abnormalities during sleep.

The purpose of this communication is to review obstructive and central breathing abnormalities that may occur during sleep, such as obstructive sleep apnea, and Cheyne-Stokes respiration. Emphasis is placed on noninvasive monitoring of the breathing pattern and intrapleural pressure swings by respiratory and surface inductive plethysmography, respectively, which establish the diagnosis of these abnormal breathing patterns.

Aminophylline↗
PubMed1983

Effects of partial anti-G suit inflation on thoracic volume and breathing pattern.

The purpose of this study was to determine the changes in thoracic volume and pattern of breathing during partial anti-G suit (PAGS) inflation by respiratory inductive plethysmography (RIP). Nine normal subjects donned the PAGS, with bladders over legs and thighs, and rested for about 10 min in 60 degrees head-up tilt position. The subjects breathed with closed glottis at functional residual capacity while PAGS was suddenly inflated to 140 mmHg using a calves to thighs sequence. The increase in thoracic volume, as measured from deflection of RIP baseline was 252 ml (S.D. 43 ml), which reflected displacement of blood from the lower extremities into the thorax. On resuming normal breathing, thoracic volume returned to baseline level. Breathing pattern was then monitored for a 15 min baseline period, PAGS was inflated, expiratory reserve volume (ERV) was measured by spirometry, and breathing pattern was monitored another 15 min. ERV decreased 227 ml (+/- 60) after PAGS inflation, which did not differ from the change in thoracic volume expected from displacement of blood into the thorax. Breathing pattern was monitored for another 15 min after PAGS was deflated. No changes took place in minute ventilation, tidal volume, frequency, inspiratory time, fractional inspiratory time, and mean inspiratory flow from deflation to PAGS inflation. Thus, 1) increase in thoracic volume produced by displacement of blood from the calves and thighs is balanced by a decrease in gas volume and, 2) no changes in breathing pattern occur after partial anti-G suit inflation, probably because the pulmonary blood vessels and heart are sufficiently distensible to accept a 250 ml volume increment without leakage of fluid into pulmonary tissues.

Adult↗
PubMed1982

Validation of respiratory inductive plethysmography using different calibration procedures.

We devised a new calibration procedure [least squares method (LSQ)] for respiratory inductive plethysmography (RIP) and compared it with our previously reported simultaneous equation method (SEQ) of analyzing data in 2 body positions and with the method of Stagg and associates using the analysis of individual breaths in a single body position. The values from RIP were compared with simultaneous spirometry (SP) in 20 normal subjects placed in the standing (STD), supine (SUP), sitting, prone, semi-recumbent, right lateral decubitus, and left lateral decubitus postures. The LSQ gave the most accurate results followed closely by SEQ. In addition, LSQ was compared with the isovolume angle maneuver (ISV) calibration procedure in supine (ISV-SUP) and standing (ISV-STD) postures. Each of the 10 normal subjects breathed at tidal volumes of 250, 750, and 1,250 ml in the SUP and STD postures. Of the values obtained by the LSQ method, 93% were within +/- 10% of SP in SUP and STD positions. Without a change in the posture in which the calibration was made, 83% of values with ISV-SUP and 90% of values with ISV-STD were within +/- 10% of SP. When body position was changed, 65% of the values obtained with ISV-SUP and 38% of the values obtained with ISV-STD were within +/- 10% of SP. With the LSQ, 45% of isovolume angles in SUP and STD position were within 45 +/- 3 degrees; 40% of isovolume angles with ISV-SUP and 60% with ISV-STD were within 45 +/- 3 degrees when body position was changed from position calibrated. In estimating fractional contribution of rib cage and abdominal compartments. LSQ was comparable to ISV in the standing posture but generally gave lesser values for the rib cage contribution in the supine posture than ISV. The optimal calibration procedure for respiratory inductive plethysmography in terms of accuracy and ease of subject performance is the least squares calibration procedure.

Calibration↗
PubMed1982

Monitoring smoking patterns of low and high tar cigarettes with inductive plethysmography.

We developed a nonobtrusive technique to measure the volume puffed during smoking. An inductive plethysmographic coli placed around the cheeks was calibrated by coaching the subject to take graded puffs from an unlit cigarette connected in series to a 2-L Krogh spirometer. The device had a linear volume response that was unaltered by smoking filtered or unfiltered cigarettes or by the length of the cigarette. It remained calibrated after smoking 4 cigarettes over 150 min. Ten subjects smoked a high tar content (HTC) and a low tar content (LTC) cigarette, each with and without a cigarette holder. The mean puff volume from LTC of 52 +/- 15 ml was significantly higher than HTC of 39 +/- 10 ml (p less than 0.001). The number of puffs per cigarette (8.4 +/- 2.1 for LTC, 8.3 +/- 2.0 for HTC), the volume of inhaled (841 +/- 517 ml for LTC and 748 +/- 323 ml for HTC), and the duration of inhalation and associated breathhold (5.5 +/- 2.6 s for LTC and 5.6 +/- 2.4 s for HTC) as measured by respiratory inductive plethysmography were comparable. The perception of intensity of inhalation by the subjects bore little relationship to the objective measurement. A cigarette holder increased the number of puffs per cigarette to 12.6 +/- 4.8 for LTC (p less than 0.02) and to 11.9 +/- 3.6 for HTC (p less than 0.01 and increased the puff volume for HTC to 50 +/- 12 ml (p less than 0.01) and the duration of inhalation to 6.6 +/- 2.5 s for LTC (p less than 0.005). These results show that (1) smokers switched acutely from HTC to LTC draw larger puffs from LTC thereby possibly circumventing the perceived benefits of smoking LTC, (2) cigarette holders modify smoking pattern and hence if used with an incorporated flowmeter to monitor the natural pattern of smoking might give spurious information.

Adult↗