Expiratory reserve volume and vital capacity of the lungs during immersion in water

1975 ◽  
Vol 38 (1) ◽  
pp. 5-9 ◽  
Author(s):  
A. B. Craig ◽  
M. Dvorak
Keyword(s):  
Hydrostatic Pressure ◽  
Negative Pressure ◽  
Vital Capacity ◽  
Spinous Process ◽  
Cervical Vertebra ◽  
Positive Pressure ◽  
Sitting Position ◽  
Anatomic Landmarks ◽  
Seventh Cervical Vertebra ◽  
Negative Pressure Breathing

The effects of immersion by 5-cm increments on the expiratory reserve volume of the lungs (ERV) and on the vital capacity were studied in the sitting and supine positions. These effects were compared to those produced by continuous negative-pressure breathing when the subjects were in air and were counteracted by positive pressure breathing during immersion. The depth of immersion was also related to definable anatomic landmarks. In the sitting position about one-fourth of the decrease in the ERV was accounted for by the hydrostatic pressure of the water on the abdomen and the remainder by the pressure on the thorax. Immersion to the level of the spinous process of the seventh cervical vertebra was equivalent to 28 cmH2o continuous negative pressure breathing in air. In the supine position, a comparable value was 8 cmH2o. These observations agree well with those of others if differences in the levels of immersion are accounted for.

Effect of continuous pressure breathing on right ventricular volumes

1967 ◽  
Vol 22 (6) ◽  
pp. 1053-1060 ◽  
Author(s):  
Maylene Wong ◽  
Edgardo E. Escobar ◽  
Gilberto Martinez ◽  
John Butler ◽  
Elliot Rapaport
Keyword(s):  
Right Ventricular ◽  
Negative Pressure ◽  
Atmospheric Pressure ◽  
Diastolic Pressure ◽  
Venous Pressure ◽  
Intrathoracic Pressure ◽  
Transmural Pressure ◽  
Positive Pressure ◽  
End Diastolic Volume ◽  
Negative Pressure Breathing

We measured the end-diastolic volume (EDV) and stroke volume (SV) in the right ventricle of anesthetized dogs during continuous pressure breathing and compared them to measurements taken during breathing at atmospheric pressure. During intratracheal positive-pressure breathing, EDV, and SV decreased and end-diastolic pressure became more positive relative to atmospheric pressure. During intratracheal negative-pressure breathing, EDV enlarged and SV tended to increase; end-diastolic pressure became more negative. During extrathoracic negative-pressure breathing SV decreased, EDV fell, though not significantly, and end-diastolic pressure rose, but insignificantly. Changes in EDV observed during intratracheal positive-pressure breathing and intratracheal negative-pressure breathing were associated with minor shifts in transmural pressure (end-diastolic pressure minus intrapleural pressure) in the expected directions, but during extrathoracic negative-pressure breathing a large increase in transmural pressure took place with the nonsignificant reduction in EDV. We believe that intrathoracic pressure influences right ventricular filling by changing the peripheral-to-central venous pressure gradient. The cause of the alteration in diastolic ventricular distensibility demonstrated during extra-thoracic negative-pressure breathing remains unexplained. positive-pressure breathing; negative-pressure breathing; extrathoracic negative-pressure breathing Submitted on August 16, 1966

Cardiopulmonary effects of continuous pressure breathing in hypothermic dogs

1965 ◽  
Vol 20 (4) ◽  
pp. 669-674 ◽  
Author(s):  
J. Salzano ◽  
F. G. Hall
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Stroke Volume ◽  
Negative Pressure ◽  
Alveolar Ventilation ◽  
Positive Pressure ◽  
Negative Pressure Breathing ◽  
Continuous Positive Pressure ◽  
Respiratory Dead Space

Continuous pressure breathing was studied in hypothermic anesthetized dogs. Alveolar ventilation decreased during continuous positive-pressure breathing and increased during continuous negative-pressure breathing. The changes in alveolar ventilation were due to changes in respiratory rate as well as in respiratory dead space. Cardiac output fell significantly during continuous positive-pressure breathing due to a reduction in heart rate and stroke volume. During continuous negative-pressure breathing cardiac output was only slightly greater than during control as a result of a fall in heart rate and an increase in stroke volume. Oxygen consumption was reduced to 60% of control during continuous positive-pressure breathing of 16 cm H2O but was 25% greater than control during continuous negative-pressure breathing. Qualitatively, CO2 production changed as did O2 consumption but was different quantitatively during continuous negative-pressure breathing indicating hyperventilation due to increased respiratory rate. Mean pulmonary artery pressures and pulmonary resistance varied directly with the applied intratracheal pressure. The results indicate that the hypothermic animal can tolerate an imposed stress such as continuous pressure breathing and can increase its oxygen consumption during continuous negative-pressure breathing as does the normothermic animal. hypothermia; respiratory dead space; metabolic rate; cardiac output Submitted on December 8, 1964

Effect of increases in lung volume on clearance of aerosolized solute from human lungs

1985 ◽  
Vol 59 (4) ◽  
pp. 1242-1248 ◽  
Author(s):  
J. D. Marks ◽  
J. M. Luce ◽  
N. M. Lazar ◽  
J. N. Wu ◽  
A. Lipavsky ◽  
...  
Keyword(s):  
Lung Volume ◽  
Negative Pressure ◽  
Ambient Pressure ◽  
Pressure Control ◽  
Positive Pressure ◽  
Healthy Humans ◽  
Human Lungs ◽  
Solute Uptake ◽  
Residual Capacity ◽  
Negative Pressure Breathing

To study the effect of increases in lung volume on solute uptake, we measured clearance of 99mTc-diethylenetriaminepentaacetic acid (Tc-DTPA) at different lung volumes in 19 healthy humans. Seven subjects inhaled aerosol (1 micron activity median aerodynamic diam) at ambient pressure; clearance and functional residual capacity (FRC) were measured at ambient pressure (control) and at increased lung volume produced by positive pressure [12 cmH2O continuous positive airway pressure (CPAP)] or negative pressure (voluntary breathing). Six different subjects inhaled aerosol at ambient pressure; clearance and FRC were measured at ambient pressure and CPAP of 6, 12, and 18 cmH2O pressure. Six additional subjects inhaled aerosol at ambient pressure or at CPAP of 12 cmH2O; clearance and FRC were determined at CPAP of 12 cmH2O. According to the results, Tc-DTPA clearance from human lungs is accelerated exponentially by increases in lung volume, this effect occurs whether lung volume is increased by positive or negative pressure breathing, and the effect is the same whether lung volume is increased during or after aerosol administration. The effect of lung volume must be recognized when interpreting the results of this method.

scholarly journals Potential Use of Transspinal Direct Current Stimulation For Cerebral Circulation Correction

2017 ◽  
Vol 8 (6) ◽  
pp. 50-55 ◽  
Author(s):  
George K. Sirbiladze ◽  
Galina A. Suslova ◽  
Dmitrij Ju. Pinchuk ◽  
Timur K. Sirbiladze
Keyword(s):  
Emotional Disorders ◽  
Direct Current ◽  
Spinous Process ◽  
Cervical Vertebra ◽  
Constant Current ◽  
Childhood And Adolescence ◽  
Lumbosacral Region ◽  
Direct Current Stimulation ◽  
Seventh Cervical Vertebra ◽  
Potential Use

Research objective: to prove the potential use of Trans spinal direct current stimulation for treatment of brain systems functioning disturbance attached with regulation of vasal tonus. Identify the most effective localizations and exposure regimens, so that in the future they can be used purposefully, for the treatment of cerebral blood flow disorders. Materials and methods. 38 children aged 4-12 years were examined who were treated with TSDCS and who had EEG at the beginning of the course of treatment – signs of hemolytic dysfunction with ICD-10 diagnoses as mental retardation (F70-F79), disorders of psychological development (F80-F89) or as behavioural and emotional disorders with onset usually occurring in childhood and adolescence (F90-F98). The following examinations were performed: an electroencephalogram, a neurological examination. The trans spinal direct current stimulation was carried out by a constant current of 100-200 μA, during 30-40 min. At the same time, the cathode was located lateral from the spinous process of the seventh cervical vertebra C7, and the anode counterlaterally to the cathode in the lumbosacral region at the level of the spinous processes L5-S1. A total of 3 to 5 sessions of TSDCS were conducted. A repeat EEG examination with the determination of Hemolucleodynamics Coefficient (HC) was performed 7-10 days after the last TSMP session. Result. After the course of TSDCS, all patients significantly decreased the HC score. In 27 patients (71%) patients, HC decreased to the norm value (≤1,2). In 23 patients (29%), HC values corresponded to the first degree of hemolytic dysfunction.

Single motor unit activity in the diaphragm of cat during pressure breathing

1981 ◽  
Vol 50 (2) ◽  
pp. 348-357 ◽  
Author(s):  
B. Bishop ◽  
S. Settle ◽  
J. Hirsch
Keyword(s):  
Motor Unit ◽  
Negative Pressure ◽  
Motor Units ◽  
Positive Pressure ◽  
Quiet Breathing ◽  
Single Motor Unit ◽  
Single Motor ◽  
Single Motor Units ◽  
Negative Pressure Breathing ◽  
Phrenic Motoneuron

In this study we analyzed the breath-by-breath activity of single motor units in the diaphragm slip of allobarbital-anesthetized cats during quiet breathing and during continuous positive- and negative-pressure breathing. Our objective was to determine whether single motor units, on the basis of their activities, can be separated into discrete subpopulations or whether they fall on a continuum analogous to that of motor units of hindlimb muscles. The firing profiles of each unit were characterized for each pressure level by the onset and peak firing frequencies, onset latency, duration of firing, number of impulses per breath, and minimal frequency, when appropriate. Units with shorter onset latencies had higher peak frequencies, longer firing durations, and increased firing frequencies than did units with longer onset latencies. These comparative relationships persisted even though the activity of every motor unit was altered during pressure breathing. During positive-pressure breathing onset latencies were lengthened, and durations of firing were shortened with little change in onset or peak frequencies. Late units might be silenced. During negative-pressure breathing onset latencies were shortened, and durations of firing were lengthened, sufficiently in some cases to fill the expiratory pause. In addition, previously inactive units were recruited late in inspiration for short, relatively high frequency bursts during inspiration. The results support the concept that the phrenic motoneuron pool is comprised of three discrete subpopulations.

Dural sinus pressure: various aspects in human brain surgery in children and adults

1986 ◽  
Vol 250 (3) ◽  
pp. H389-H396
Author(s):  
T. Iwabuchi ◽  
E. Sobata ◽  
K. Ebina ◽  
H. Tsubakisaka ◽  
M. Takiguchi
Keyword(s):  
Negative Pressure ◽  
Air Embolism ◽  
The Body ◽  
Dural Sinus ◽  
Positive Pressure ◽  
Brain Surgery ◽  
Sitting Position ◽  
Group A ◽  
Group B ◽  
Sinus Pressure

To prevent air embolism and minimize neurosurgical venous hemorrhage, the dural sinus pressure (confluens sinuum pressure, CSP) was examined under various conditions in 47 cases, 11 of whom were children. Either the extracranial (group A) or catheter type (group B) pressure transducer was used. The latter gave approximately 30% higher values than the former. In any surgical position, children showed a tendency toward higher pressure than did adults. This was particularly the case in the sitting position; adults showed negative pressure [-8.6 +/- 2.3 (SD) mmHg, group A], whereas all eight children less than 9 yr of age (group A, 5 cases; group B, 3 cases) showed positive pressure. The youngest with negative CSP in a sitting position was a 9-yr-old boy. When the upper half of the body was raised, the CSP decreased linearly and became zero at approximately 25 degrees. In anteflexion of the neck, the CSP decreased significantly, and even with inclination of the upper half of the body of only 15-20 degrees or more upward, negative pressure was observed in adults. In children, right and left rotation of the neck showed remarkable increase of the CSP. In both supine and sitting positions, CSP was elevated sufficiently by bilateral jugular compression to prevent air embolism. Positive-pressure respiration did not raise the CSP, contrary to widely accepted knowledge. This study was originally performed in relation to brain surgery, but the results also seemed to be valuable in physiology.

Effect of negative-pressure breathing on lung mechanics and venous admixture

1964 ◽  
Vol 19 (4) ◽  
pp. 665-671 ◽  
Author(s):  
Tulio Velasquez ◽  
Leon E. Farhi
Keyword(s):  
Negative Pressure ◽  
Lung Compliance ◽  
Lung Mechanics ◽  
Positive Pressure ◽  
Venous Admixture ◽  
Respiratory Compliance ◽  
Anesthetized Dogs ◽  
Flow Through ◽  
Negative Pressure Breathing ◽  
Opening And Closing

Anesthetized dogs in the supine position show a spontaneous decrease in total respiratory compliance and an increase in venous admixture to the pulmonary circulation. Both these changes can be increased by negative-pressure breathing and reversed by positive-pressure breathing. If the changes in total respiratory compliance are due only to changes in lung compliance and these in turn result directly from the closure of alveoli, the relationship between compliance and inspiratory and expiratory pressure allows one to determine the scatter of opening and closing pressures in the alveoli. The venous admixture measures blood flow through collapsed alveoli, and its relationship to the negative pressure applied indicates the perfusion of the alveoli collapsing with each increment in negative pressure. By studying simultaneously changes in compliance and venous admixture, and using two basic assumptions, the dog's lungs can be described as a system composed of some elements receiving nearly 50% of the ventilation and 20% of the perfusion, relatively unstable mechanically, and having a very high Va/ Q ratio, while the remaining air spaces receive the same ventilation, but 80% of the perfusion. lung compliance; atelectasis; ventilation-perfusion ratio Submitted on October 28, 1963

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