scholarly journals Broad individual immersion-scattering of respiratory compliance likely substantiates dissimilar breathing mechanics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Olivier Castagna ◽  
Guillaume Michoud ◽  
Thibaut Prevautel ◽  
Antoine Delafargue ◽  
Bruno Schmid ◽  
...  
Keyword(s):  
Respiratory System ◽  
Water Immersion ◽  
Work Of Breathing ◽  
Adult Group ◽  
Respiratory Compliance ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Diving Medicine ◽  
Breathing Mechanics ◽  
Diverse Individual

AbstractHead-out water immersion alters respiratory compliance which underpins defining pressure at a “Lung centroid” and the breathing “Static Lung Load”. In diving medicine as in designing dive-breathing devices a single value of lung centroid pressure is presumed as everyone’s standard. On the contrary, we considered that immersed respiratory compliance is disparate among a homogenous adult group (young, healthy, sporty). We wanted to substantiate this ample scattering for two reasons: (i) it may question the European standard used in designing dive-breathing devices; (ii) it may contribute to understand the diverse individual figures of immersed work of breathing. Resting spirometric measurements of lung volumes and the pressure–volume curve of the respiratory system were assessed for 18 subjects in two body positions (upright Up, and supine Sup). Measurements were taken in air (Air) and with subjects immersed up to the sternal notch (Imm). Compliance of the respiratory system (Crs) was calculated from pressure–volume curves for each condition. A median 60.45% reduction in Crs was recorded between Up-Air and Up-Imm (1.68 vs 0.66 L/kPa), with individual reductions ranging from 16.8 to 82.7%. We hypothesize that the previously disregarded scattering of immersion-reduced respiratory compliance might participate to substantial differences in immersed work of breathing.

Significance of the Changes in the Respiratory System Pressure–Volume Curve during Acute Lung Injury in Rats

2001 ◽  
Vol 164 (4) ◽  
pp. 627-632 ◽  
Author(s):  
LAURENT MARTIN-LEFÈVRE ◽  
JEAN-DAMIEN RICARD ◽  
ERIC ROUPIE ◽  
DIDIER DREYFUSS ◽  
GEORGES SAUMON
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Respiratory System ◽  
System Pressure ◽  
Volume Curve ◽  
Pressure Volume Curve

scholarly journals The influence of the post-pulmonary septum and submersion on the pulmonary mechanics of Trachemys scripta (Cryptodira: Emydidae)

2021 ◽  
Author(s):  
Ray Brasil Bueno de Souza ◽  
Wilfried Klein
Keyword(s):  
Hydrostatic Pressure ◽  
Respiratory System ◽  
Intact Animal ◽  
Work Of Breathing ◽  
Dynamic Compliance ◽  
Body Cavity ◽  
Trachemys Scripta ◽  
Pulmonary Mechanics ◽  
Static Compliance ◽  
Breathing Mechanics

The respiratory system of chelonians needs to function within a mostly solid carapace, with ventilation depending on movements of the flanks. When submerged, inspiration has to work against a hydrostatic pressure and we examined breathing mechanics in Trachemys scripta while underwater. Furthermore, the respiratory system of T. scripta possesses a well-developed post-pulmonary septum (PPS), and we investigated its role on breathing mechanics of lungs with and without their PPS attached. Static compliance was significantly increased in submerged animals and in animals with and without their PPS, while the removal of the PPS did not result in a significantly different static compliance. Dynamic compliance was significantly affected by changes in volume and frequency in every treatment, with submergence significantly decreasing dynamic compliance. The presence of the PPS significantly increased dynamic compliance. Submersion did not alter significantly work per ventilation, but caused minute work of breathing to be much greater at any frequency and ventilation level analyzed. Lungs with or without their PPS did not show significantly different work per ventilation when compared to intact animal. Our results demonstrate that submersion results in significantly altered breathing mechanics, increasing minute work of breathing greatly. The PPS was shown to maintain a constant volume within the animal's body cavity, wherein the lungs can be ventilated more easily, highlighting the importance of this coelomic subdivision in the chelonian body cavity.

scholarly journals Quantification of Alveolar Recruitment for the Optimization of Mechanical Ventilation Using Quasi-Static Pressure Volume Curve

2018 ◽  
Author(s):  
Mohsen Nabian ◽  
Uichiro Narusawa
Keyword(s):  
Mechanical Ventilation ◽  
Respiratory System ◽  
Distress Syndrome ◽  
Alveolar Recruitment ◽  
System Optimum ◽  
Quantitative Characterization ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Ventilation Setting

Quasi-static, pulmonary pressure-volume (P-V) curves over an inflation-deflation cycle are analyzed using a respiratory system model (RSM), which had been developed for quantitative characterization of the mechanical behavior of the total respiratory system. Optimum mechanical ventilation setting of Positive End Expiratory Pressure (PEEP) for total alveolar recruitment is quantified based on the existing P-V curves of healthy and injured animal models. Our analytical predictions may contribute to the optimization of mechanical ventilation settings for the Acute Respiratory Distress Syndrome (ARDS) patients.

Comparative aspects of the dynamics of breathing in newborn mammals

1983 ◽  
Vol 54 (5) ◽  
pp. 1229-1235 ◽  
Author(s):  
J. P. Mortola
Keyword(s):  
Body Size ◽  
Respiratory System ◽  
Dynamic Properties ◽  
Upper Airway ◽  
Lung Compliance ◽  
Expiratory Time ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Dynamic Lung Compliance ◽  
Spontaneously Breathing

Static and dynamic properties of the respiratory system have been studied in anesthetized, tracheostomized newborns of six species, ranging in size from rats to piglets. Respiratory system compliance (Crs), total resistance of respiratory system (Rrs), and expiratory time constant (tau) have been measured in the paralyzed passively ventilated animals. Crs is found to be proportional to body weight (BW0.80) and Rrs to BW-0.75; tau is independent of body size, the shortest value being in kittens and guinea pigs and a value of about 0.14 s in the other species. Including the upper airway resistance, tau becomes approximately 0.22 s. This value is similar to the expiratory time of the fastest breathing species; therefore in the smallest species the high breathing rate can be regarded as a mechanism to raise end-expiratory level. On a few occasions, dynamic lung compliance and pulmonary resistance, measured in spontaneously breathing kittens, puppies, and piglets were, respectively, smaller and larger than Crs and Rrs, suggesting that the hysteresis of the pressure-volume curve may be substantial. Rrs was almost linear within the volume and flow range investigated, with the Rohrer's constant K2 always being less than 2.5% of K1. The Reynolds number increases with body size (alpha BW0.51) more than is predictable from the changes in tracheal diameter, since the tracheal flow velocity is not an interspecific constant.

Surfactant Activity and the Pressure-Volume Curve of the Respiratory System

2021 ◽  
pp. 235-241
Author(s):  
Charles Corey Hardin ◽  
Roger G. Spragg ◽  
Atul Malhotra
Keyword(s):  
Respiratory System ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Surfactant Activity

Effect of immersion on intrapulmonary pressure

1965 ◽  
Vol 20 (6) ◽  
pp. 1261-1266 ◽  
Author(s):  
A. S. Jarrett
Keyword(s):  
Center Of Pressure ◽  
Water Immersion ◽  
Breath Holding ◽  
Regression Equations ◽  
Volume Relaxation ◽  
Diving Physiology ◽  
Volume Curve ◽  
Pressure Axis ◽  
Pressure Volume Curve ◽  
Relaxation Curves

Pressure-volume relaxation curves have been determined for relaxed, breath-holding subjects lying and sitting in air and water. Immersion in water resulted in a marked increase in intrapulmonary pressure, the whole pressure-volume curve appearing to be shifted along the pressure axis. From the regression equations of the four curves the pressures at normal relaxed chest volume were calculated, and the center of pressure of the immersed chest shown to lie 19 cm below and 7 cm behind the sternal angle. The significance of this to the positioning of a diver's demand valve is discussed. center of pressure of thorax; immersion and chest volume; eupneic pressure; diving physiology; underwater respiration Submitted on September 10, 1964

scholarly journals Compliance of the respiratory system and its components in health and obesity

1960 ◽  
Vol 15 (3) ◽  
pp. 377-382 ◽  
Author(s):  
A. Naimark ◽  
R. M. Cherniack
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Work Of Breathing ◽  
Normal Subjects ◽  
Respiratory Compliance ◽  
Elastic Resistance ◽  
Normal Individuals ◽  
Obese Subjects ◽  
The Difference ◽  
Mean Compliance

The compliance of the total respiratory system and its components was studied in 24 normal and 12 obese spontaneously breathing unanesthetized subjects. The mean compliance of the total respiratory system was .119 l/cm H2O in normal individuals, but was .052 l/cm H2O in obese subjects. The difference indicated an increased elastic resistance to distention. The compliance of the lung in obese individuals was not different from that of the normals. The compliance of the chest wall was .224 l/cm H2O in normal subjects and was .077 l/cm H2O in obese individuals. In contrast to normal subjects, total respiratory compliance was markedly reduced by recumbency in obese individuals. This was entirely due to a further increase in the resistance of the chest wall. A significant correlation was demonstrated between vital capacity and total respiratory compliance in normal and obese subjects. It has been estimated that of the increase in the mechanical work of breathing in obesity is due to elastic work done on the chest wall. Submitted on November 2, 1959

Respiratory mechanics in adult rats hypercapnic in the neonatal period

1990 ◽  
Vol 68 (6) ◽  
pp. 2274-2279 ◽  
Author(s):  
R. Rezzonico ◽  
R. D. Gleed ◽  
J. P. Mortola
Keyword(s):  
Mechanical Properties ◽  
Respiratory System ◽  
Neonatal Period ◽  
Statistical Significance ◽  
Lung Compliance ◽  
Long Term Effects ◽  
Adult Rats ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
And Control

Because chronic hypoxia in the neonatal period has long-term effects on the mechanical properties of the respiratory system (S. Okubo and J. P. Mortola, J. Appl. Physiol. 66: 1772-1778, 1989), we asked whether similar effects would occur after neonatal exposure to hypercapnia. Three groups of rats were used. The first was exposed to 7% CO2 in normoxia from day 1 to 7 after birth and then returned to normocapnia (NB-CO2). The second was exposed to the same level and duration of hypercapnia from day 36 to 42, i.e., approximately 2 wk after weaning (AD-CO2). The third was raised in normoxia and normocapnia (control). At approximately 50 days, i.e., 1-2 wk after puberty, the passive mechanical properties of the respiratory system, lung, and chest were measured during artificial ventilation in the anesthetized and paralyzed animal. No differences were observed between AD-CO2 and control. NB-CO2 had higher compliance of the lung (approximately +40%) and respiratory system (+32%) than control or AD-CO2. Average values of resistance of the total respiratory system, lung, and chest wall were consistently lower in NB-CO2 than in control and AD-CO2, although the magnitude and statistical significance of the decrease depended on the method of measurement. In a separate group of NB-CO2, lung compliance was measured during spontaneous breathing, and it averaged 34% more than in control. The exponential constant of the deflation quasi-static pressure-volume curve of the liquid-filled lungs was also significantly higher than in control.(ABSTRACT TRUNCATED AT 250 WORDS)

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