The influence of posture on the respiratory system resistance in eutrophic and obese subjects

2017 ◽  
Author(s):  
Mayara Holtz de Paula ◽  
Larissa Perossi Nascimento ◽  
Daniele Oliveira dos Santos ◽  
Letícia Helena De Souza ◽  
José Antônio Baddini Martinez ◽  
...  
Keyword(s):  
Respiratory System ◽  
Obese Subjects ◽  
Respiratory System Resistance

Mechanics of the respiratory system in the newborn tammar wallaby

2002 ◽  
Vol 205 (4) ◽  
pp. 533-538 ◽  
Author(s):  
P. M. MacFarlane ◽  
P. B. Frappell ◽  
J. P. Mortola
Keyword(s):  
Respiratory System ◽  
Spontaneous Breathing ◽  
Minute Ventilation ◽  
Pulmonary Ventilation ◽  
Age Groups ◽  
Mechanical Efficiency ◽  
Tammar Wallaby ◽  
Ventilatory Equivalent ◽  
Rate Of Oxygen Consumption ◽  
Respiratory System Resistance

SUMMARY We investigated whether the mechanical properties of the respiratory system represent a major constraint to spontaneous breathing in the newborn tammar wallaby Macropus eugenii, which is born after a very short gestation (approximately 28 days, birth mass approximately 380 mg). The rate of oxygen consumption (V̇O2) through the skin was approximately 33 % of the total V̇O2 at day 1 and approximately 14 % at day 6. The mass-specific resting minute ventilation (V̇e) and the ventilatory equivalent (V̇e/V̇O2) were approximately the same at the two ages, with a breathing pattern significantly deeper and slower at day 1. The mass-specific compliance of the respiratory system (Crs) did not differ significantly between the two age groups and was close to the values predicted from measurements in eutherian newborns. Mass-specific respiratory system resistance (Rrs) at day 1 was higher than at day 6, and also higher than in eutherian newborns. Chest distortion, quantified as the degree of abdominal motion during spontaneous breathing compared with that required to inflate the lungs passively, at day 1 was very large, whereas it was modest at day 6. We conclude that, in the tammar wallaby at birth, the high resistance of the respiratory system and the distortion of the chest wall greatly reduce the mechanical efficiency of breathing. At this age, gas exchange through the skin is therefore an important complement to pulmonary ventilation.

Influence of human vocal cord movements on airflow and resistance during eupnea

1982 ◽  
Vol 52 (3) ◽  
pp. 773-779 ◽  
Author(s):  
S. J. England ◽  
D. Bartlett ◽  
J. A. Daubenspeck
Keyword(s):  
Vocal Cord ◽  
Respiratory System ◽  
Forced Oscillation Technique ◽  
Quiet Breathing ◽  
Vocal Cords ◽  
Healthy Human ◽  
Breathing Motion ◽  
Human Volunteers ◽  
Respiratory System Resistance ◽  
Respiratory Movements

The pattern of respiratory movements of the vocal cords in relation to airflow and respiratory system resistance was assessed in healthy human volunteers during quiet breathing. Motion pictures of the vocal cords were obtained through a fiber-optic laryngoscope inserted transnasally under topical anesthesia. A simultaneous estimate of lung volume was obtained using either rib cage and abdominal magnetometer coils or an integrated pneumotachograph signal. The vocal cords separated during inspiration and moved closer together during the expiratory phase of each breath. The extent of these movements varied greatly among the subjects. Total respiratory system resistance, assessed by the forced oscillation technique, was negatively correlated with distance between the vocal cords when measured at isoflow points in inspiration and expiration. Analysis of breath-by-breath variations in expiratory airflow and vocal cord position revealed that decreases in airflow accompanied decreases in the distance between the vocal cords. The results of this study indicate that the human larynx participates in the regulation of respiratory airflow by providing a variable, controlled resistance.

Quantification of nasal involvement in a guinea pig plethysmograph

1994 ◽  
Vol 76 (4) ◽  
pp. 1432-1438 ◽  
Author(s):  
M. J. Finney ◽  
K. I. Forsberg
Keyword(s):  
Lung Function ◽  
Guinea Pig ◽  
Respiratory System ◽  
Guinea Pigs ◽  
Repeated Measurement ◽  
Whole Body ◽  
Nasal Resistance ◽  
Rapid Technique ◽  
Respiratory System Resistance ◽  
Lower Airways

We have developed a technique for measuring lung function in conscious guinea pigs using a whole body plethysmograph. Because guinea pigs breathe through the nose, a technique was also developed to measure nasal and lower respiratory system conductance simultaneously in anesthetized animals. The upper and the lower airways could be challenged separately and studied in a manner similar to the conditions in the plethysmograph. Aerosols of histamine, carbachol, or ovalbumin delivered to the nose in sensitized animals had no effect on nasal conductance, even in doses 100 times higher than that required to reduce lower respiratory system conductance. However, intravenous histamine increased nasal conductance. Thus, although nasal resistance constitutes the majority of the total respiratory system resistance measured in the plethysmograph, nasal resistance is unaffected by the aerosol drugs studied. We therefore consider changes in resistance measured in the plethysmograph to originate at or below the larynx. The plethysmographic technique described here is a reliable, reproducible, and rapid technique that enables repeated measurement in animals and minimizes animal trauma.

Ontogeny of dry gas hyperpnea-induced bronchoconstriction in guinea pigs

1994 ◽  
Vol 76 (3) ◽  
pp. 1150-1155 ◽  
Author(s):  
T. M. Murphy ◽  
D. W. Ray ◽  
L. E. Alger ◽  
I. J. Phillips ◽  
J. C. Roach ◽  
...  
Keyword(s):  
Respiratory System ◽  
Guinea Pigs ◽  
Minute Ventilation ◽  
Similar Degree ◽  
Fractional Increase ◽  
Respiratory System Resistance ◽  
Key Features

Adolescent guinea pigs (AGPs) demonstrate dry gas hyperpnea-induced bronchoconstriction (HIB) that shares key features with HIB in humans with asthma. The airways of immature animals exhibit enhanced reactivity to diverse types of stimulation. We tested whether dry gas HIB is also increased in newborn guinea pigs (NGPs). We quantified HIB as the fractional increase of respiratory system resistance (Rrs) over baseline (BL) in five 4- to 7-day-old NGPs after 10 min of hyperpnea, as well as changes in Rrs elicited by intravenous methacholine or capsaicin, and compared these responses with those of AGPs. During hyperpnea, analogous stimuli were delivered by mechanically imposing hyperpnea at 3.0, 4.5, and 6.0 times quiet eucapnic minute ventilation (VE). In AGPs, hyperpnea caused significant bronchoconstriction that increased with VE; peak fractional increase of Rrs was 7.6 +/- 2.0 times BL. In contrast, hyperpnea caused insignificant bronchoconstriction in NGPs (1.4 +/- 0.2 times BL after the largest VE; P < 0.05 vs. AGP). Responses elicited by methacholine (10(-10)-10(-7) mol/kg) or capsaicin (0.01–10.0 microgram/kg) were similar in NGPs and AGPs. In AGPs, hyperpnea suppressed HIB until posthyperpnea. To determine whether the reduced HIB of NGPs was caused by enhanced suppression, NGPs and AGPs were administered acetylcholine (10(-10)-10(-7) mol/kg i.v.) during BL eucapnic ventilation and during eucapnic hyperpnea with warm humidified gas. Responses to acetylcholine were suppressed in AGPs and NGPs to a similar degree. We conclude that HIB is markedly diminished shortly after birth in guinea pigs and that it increases substantially during maturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Hyperoxia-induced airway hyperresponsiveness and remodeling in immature rats

1993 ◽  
Vol 265 (2) ◽  
pp. 1-1
Author(s):  
Marc B. Hershenson ◽  
Shahriar Aghili ◽  
Naresh Punjabi ◽  
Claudia Hernandez ◽  
Daniel W. Ray ◽  
...  
Keyword(s):  
Respiratory System ◽  
Airway Hyperresponsiveness ◽  
Calibration Error ◽  
Hand Column ◽  
Right Hand ◽  
Immature Rats ◽  
Respiratory System Resistance

Pages L263–L269: Hershenson, Marc B., Shahriar Aghili, Naresh Punjabi, Claudia Hernandez, Daniel W. Ray, Allan Garland, Seymour Glagov, and Julian Solway. “Hyperoxia-induced airway hyperresponsiveness and remodeling in immature rats.” Page 264: right-hand column, 2nd paragraph in the results section, the first sentence, with corrected values, should read: There was no difference in baseline Rrs between air-exposed and O2-exposed rats (control, n = 20, 0.348 ± 0.212 cmH2O·ml-1·s; hyperoxia, n = 19, 0.252 ± 0.078 cmH2O·ml-1·s; NS). Since all of our other calculations were based on changes in respiratory system resistance relative to baseline, the major findings and conclusions of the article are not altered by this calibration error.

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