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Biomedical subjects

M A Sackner

Publications and source records attributed to M A Sackner.

At least 181 records · Page 10Linked to original sources
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Mucociliary transport.

Our laboratory has developed bronchofiberscopic and roentgenographic techniques to measure tracheal, bronchial and nasal mucus velocities in humans and animals. We found that inhalation of specific antigen is associated with depression of tracheal mucus velocity in dogs who may or may not display bronchospasm and the mediator for this phenomenon might be SRS-A. Corroboration of the depression of tracheal mucus transport after ragweed inhalation has been obtained in susceptible asthmatic patients; prior inhalation of cromolyn blocks this reaction. Depression of tracheal mucus transport may be the earliest adverse manifestation of cigarette smoking in young subjects. Slowing of mucus transport in the bronchi occurs after suctioning with suction catheters; a newly designed suction catheter tip, the Aero-Flo, displays less adverse effects on mucus velocity than standard end hold and side hole catheters. Nasal mucus velocity is enhanced by nasal decongestants, ingestion of hot fluids and exercise.

Animals↗
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Effect of airway diameter, suction catheters, and the bronchofiberscope on airflow in endotracheal and tracheostomy tubes.

Pressure-flow relationships of an artificial airway-mechanical ventilator system were investigated. Endotracheal tubes varying from 7 to 9.5 mm. internal diameter and tracheostomy tubes from 7 to 10 mm. internal diameter were tested over flow-rates from 0.3 to 1.4 L. per second using a tidal volume of 500 ml. The effect of partial obstruction within these airways by suction catheters and the bronchofiberscope was examined. Depending on the internal diameter and the flow-rate, the driving pressure necessary to overcome the resistance of the tubes ranged from 5 to 20 cm. H2O. Partial obstruction of the artificial airways by suction catheters further increased this pressure. The introduction of the bronchofiberscope through an endotracheal tube of 7.5 mm. internal diameter, leaving an effective diameter of 4.9 mm., produced a driving pressure as high as 70 cm. H2O and reduced the flow rate to 50 per cent and the tidal volume to 80 per cent of its set value. Attention should be paid to duration of tracheobronchial suction while the patient is removed from the respirator since a high-grade resistance is created by passage of a suction catheter through an endotracheal tube. Bronchofiberscopy should be cautiously performed through cuffed artificial airways with at least 8 mm. internal diameter because the airway may be too comprised even if mechanical ventilatory assistance is employed.

Bronchoscopes↗
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Automated system for measurement of mechanics of breathing.

We describe a complete automated system for measurement of total respiratory resistance and compliance, and of pulmonary resistance and compliance in humans and anesthetized animals. The device for testing the chest-lung system consists of a sinusoidal pump with a stroke adjustable from 20 ml to 600 ml over a cycling frequency of 0.3 to 30 Hz. Pressure and flow or volume are inputted into an analog network for wave shaping, then to an arithmetic unit composed of sample-and-hold amplifiers, peak, minimum and zero detecting circuits, an analog division circuit, and a digital logic processor. The computer takes the peak-to-peak amplitude of one of two sinusoidal inputs at 0.3 to 10 Hz and the corresponding amplitude of the other input in the presence of a.c. noise and d.c. shifts, divides one into the other, and displays an answer on a digital voltmeter. In addition, the analog output is displayed on the cathode-ray tube of a storage oscilloscope. Plots of total resistance and pulmonary resistance are recorded as a function of lung volume in both humans inspiring voluntarily as well as anesthetized dogs inflated by positive pressure from the test apparatus. Total and pulmonary dynamic compliance, as a function of breathing frequency, can only be measured by the computer if a symmetrical waveform is presented to it. This cannot be achieved in spontaneously breathing subjects but is accomplished in apneic animals by producing sinusoidal oscillations from the test apparatus. Our on-line method for measurement of total respiratory resistance is now used in the Clinical Pulmonary Laboratory for experimental work, and we are in the process of obtaining values in normal subjects.

Adult↗
PubMedDate not supplied

Non-invasive semi-quantitative measurements of tidal pressure-volume and flow relations of lung in COPD patients.

Movement of the suprasternal fossa as detected by surface inductive plethysmography (SIP) has been utilized as a non-invasive means for estimation of intrapleural pressure in the calculation of lung compliance. The purpose of the present study was to ascertain whether pulmonary resistance and work of breathing could also be obtained with SIP. A new calibration procedure based upon substituting values for inspiratory total respiratory resistance measured by forced oscillations into an uncalibrated SIP deflection-flow loop was utilized to convert the SIP waveform to a pressure recording. This permitted estimation of lung compliance, expiratory pulmonary resistance and work of breathing which were then compared to simultaneously measured intraesophageal pressure derived values. Nine seated patients with varying degrees of obstructive airways disease were studied. No differences were found between the SIP and intraesophageal derived group mean values for any parameters, viz inspiratory and expiratory pulmonary resistance, lung compliance and work of breathing. The least variable measurement between the two methods was the work of breathing in which eight of the nine patients had values deviating less than 25% from unity. Values for lung compliance were slightly more divergent and expiratory pulmonary resistance showed large variation. The present investigation indicates that surface inductive plethysmographic detection of suprasternal fossa movement reflects intrapleural pressure swings in a semiquantitative manner; it serves as a non-invasive research technique for estimation of lung compliance, pulmonary resistance and work of breathing.

Adult↗
PubMedDate not supplied

Effects of ultrasonically nebulized distilled water on respiratory resistance and breathing pattern in normals and asthmatics.

The purpose of this study was to analyze changes in respiratory resistance (Rrs) and breathing pattern in normal and asthmatic subjects after exposure to ultrasonically nebulized distilled water (UNDW). After measurement of baseline Rrs and breathing pattern, ten normals inhaled UNDW for 30, 60, 120, 240 and 480 s administered at 15 min intervals. After the 480 s exposure, subjects inhaled two puffs of metaproterenol. Rrs was measured immediately before and after each exposure to UNDW and after metaproterenol while breathing pattern was continuously monitored. Ten asthmatics were exposed to UNDW and metaproterenol in a similar time sequence, but the durations of exposure to UNDW were 15, 30, 60, 120 and 240 s. Mean (+/- SD) and frequency histograms of minute ventilation (VE), tidal volume (VT), frequency, inspiratory time, fractional inspiratory time, mean inspiratory flow (VT/TI) and end-expiratory level at baseline were compared to values after each exposure to UNDW and after metaproterenol. All subjects experienced laryngeal irritation or cough during the exposure. In normals, there were no changes in Rrs or any of the components of breathing pattern. In asthmatics, 15 and 30 s exposures produced no changes in Rrs or breathing pattern. With subsequent longer exposures, mean Rrs showed a stepwise significant increase, along with parallel increases of VT/TI and end-expiratory level. VE increased after 60 and 120 s exposure, but reached a plateau after 240 s exposure despite continued increase in Rrs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗