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

THE EFFICIENCY OF THE RESPIRATORY MUSCLES IN OBESITY

1961 ◽  
Vol 39 (8) ◽  
pp. 1215-1222 ◽  
Author(s):  
Reuben M. Cherniack ◽  
Clarence A. Guenter
Keyword(s):  
Chest Wall ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Oxygen Cost ◽  
Chest Wall Compliance ◽  
Elastic Resistance ◽  
Lower Lung ◽  
Wall Compliance ◽  
Obese Subjects ◽  
Work Done

The work done to overcome the elastic resistance and the efficiency of the respiratory muscles were determined in normal and obese subjects. The work done was no greater in the obese subjects, but the efficiency of the muscles was low. These findings suggest that the high oxygen cost of breathing in obesity is due to inefficient respiratory muscles rather than to an increased amount of work required to overcome elastic resistance. When an extrapulmonary elastic resistance was applied to the normal subjects, the compliance of the chest wall and the efficiency of the respiratory muscles fell to the level of that in the obese. This suggests that the inefficiency of the respiratory muscles of obese individuals may have been due to the reduced chest wall compliance or to the lower lung volume at which ventilation took place.

Respiratory mechanics in the anesthetized rat

1978 ◽  
Vol 45 (2) ◽  
pp. 255-260 ◽  
Author(s):  
Y. L. Lai ◽  
J. Hildebrandt
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Esophageal Pressure ◽  
Gas Content ◽  
Lung Capacity ◽  
Consistent Change ◽  
Residual Capacity ◽  
Wall Compliance ◽  
The Difference ◽  
Body Plethysmograph

Functional residual capacity (FRC) and pressure-volume (PV) curves of the lung, chest wall, and total respiratory system were studied in 15 anesthetized rats, weighing 307 +/- 10 (SE) g. Pleural pressure was estimated from the esophageal pressure measured with a water-filled catheter. The FRC determined by body plethysmograph was slightly and significantly larger than FRC determined from saline displacement of excised lungs. The difference may be accounted for by O2 uptake by lung tissue, escape of CO2 through the pleura, and abdominal gas. Paralysis in the prone position did not affect FRC, and abdominal gas content contributed only slightly to the FRC measured by body plethysmograph. Values of various pulmonary parameters (mean +/- SE) were as follows: residual volume, 1.26 +/- 0.13 ml; FRC, 2.51 +/- 0.20 ml; total lung capacity, 12.23 +/- 0.55 ml; compliance of the lung, 0.90 +/- 0.06 ml/cmH2O; chest wall compliance, 1.50 +/- 0.11 ml/cmH2O; and respiratory system compliance, 0.57 +/- 0.03 ml/cmH2O. The lung PV curve did not show a consistent change after the chest was opened.

Positive End-expiratory Pressure Improves Respiratory Function in Obese but not in Normal Subjects during Anesthesia and Paralysis 

1999 ◽  
Vol 91 (5) ◽  
pp. 1221-1221 ◽  
Author(s):  
Paolo Pelosi ◽  
Irene Ravagnan ◽  
Gabriella Giurati ◽  
Mauro Panigada ◽  
Nicola Bottino ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Chest Wall ◽  
Body Mass ◽  
Respiratory System ◽  
Respiratory Function ◽  
Normal Subjects ◽  
Intraabdominal Pressure ◽  
Morbidly Obese ◽  
Obese Patients ◽  
Positive End Expiratory Pressure

Background Morbidly obese patients, during anesthesia and paralysis, experience more severe impairment of respiratory mechanics and gas exchange than normal subjects. The authors hypothesized that positive end-expiratory pressure (PEEP) induces different responses in normal subjects (n = 9; body mass index < 25 kg/m2) versus obese patients (n = 9; body mass index > 40 kg/m2). Methods The authors measured lung volumes (helium technique), the elastances of the respiratory system, lung, and chest wall, the pressure-volume curves (occlusion technique and esophageal balloon), and the intraabdominal pressure (intrabladder catheter) at PEEP 0 and 10 cm H2O in paralyzed, anesthetized postoperative patients in the intensive care unit or operating room after abdominal surgery. Results At PEEP 0 cm H2O, obese patients had lower lung volume (0.59 +/- 0.17 vs. 2.15 +/- 0.58 l [mean +/- SD], P < 0.01); higher elastances of the respiratory system (26.8 +/- 4.2 vs. 16.4 +/- 3.6 cm H2O/l, P < 0.01), lung (17.4 +/- 4.5 vs. 10.3 +/- 3.2 cm H2O/l, P < 0.01), and chest wall (9.4 +/- 3.0 vs. 6.1 +/- 1.4 cm H2O/l, P < 0.01); and higher intraabdominal pressure (18.8 +/-7.8 vs. 9.0 +/- 2.4 cm H2O, P < 0.01) than normal subjects. The arterial oxygen tension was significantly lower (110 +/- 30 vs. 218 +/- 47 mmHg, P < 0.01; inspired oxygen fraction = 50%), and the arterial carbon dioxide tension significantly higher (37.8 +/- 6.8 vs. 28.4 +/- 3.1, P < 0.01) in obese patients compared with normal subjects. Increasing PEEP to 10 cm H2O significantly reduced elastances of the respiratory system, lung, and chest wall in obese patients but not in normal subjects. The pressure-volume curves were shifted upward and to the left in obese patients but were unchanged in normal subjects. The oxygenation increased with PEEP in obese patients (from 110 +/-30 to 130 +/- 28 mmHg, P < 0.01) but was unchanged in normal subjects. The oxygenation changes were significantly correlated with alveolar recruitment (r = 0.81, P < 0.01). Conclusions During anesthesia and paralysis, PEEP improves respiratory function in morbidly obese patients but not in normal subjects.

Mechanism of detection of resistive loads in conscious humans

1992 ◽  
Vol 72 (6) ◽  
pp. 2267-2270 ◽  
Author(s):  
A. Puddy ◽  
G. Giesbrecht ◽  
R. Sanii ◽  
M. Younes
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Primary Source ◽  
Intrathoracic Pressure ◽  
Normal Subjects ◽  
Resistive Load ◽  
Load Detection ◽  
Elastic Load ◽  
Resistive Loads ◽  
Source Of Information

Conscious humans easily detect loads applied to the respiratory system. Resistive loads as small as 0.5 cmH2O.l-1.s can be detected. Previous work suggested that afferent information from the chest wall served as the primary source of information for load detection, but the evidence for this was not convincing, and we recently reported that the chest wall was a relatively poor detector for applied elastic loads. Using the same setup of a loading device and body cast, we sought resistive load detection thresholds under three conditions: 1) loading of the total respiratory system, 2) loading such that the chest wall was protected from the load but airway and intrathoracic pressures experienced negative pressure in proportion to inspiratory flow, and 3) loading of the chest wall alone with no alteration of airway or intrathoracic pressure. The threshold for detection for the three types of load application in seven normal subjects was 1.17 +/- 0.33, 1.68 +/- 0.45, and 6.3 +/- 1.38 (SE) cmH2O.l-1.s for total respiratory system, chest wall protected, and chest wall alone, respectively. We conclude that the active chest wall is a less potent source of information for detection of applied resistive loads than structures affected by negative airway and intrathoracic pressure, a finding similar to that previously reported for elastic load detection.

scholarly journals The Standardized Normal Ivy Bleeding Time and Its Prolongation by Aspirin

Blood ◽  
1969 ◽  
Vol 34 (2) ◽  
pp. 204-215 ◽  
Author(s):  
C. H. MIELKE ◽  
M. M. KANESHIRO ◽  
I. A. MAHER ◽  
J. M. WEINER ◽  
S. I. RAPAPORT
Keyword(s):  
Bleeding Time ◽  
Normal Subjects ◽  
Tolerance Test ◽  
Time Data ◽  
Double Blind ◽  
Large Size ◽  
Normal Individuals ◽  
The Mean ◽  
The Difference ◽  
Normal Males

Abstract A standardized, reproducible Ivy bleeding time technic has been described which permits one to obtain accurate bleeding time data in man. The technic was used to standardize an aspirin tolerance test in which 60 normal males had a control bleeding time; were given, on a double blind basis, either placebo or 1 Gm. of aspirin, and had a second bleeding time 2 hours later. The control values were: mean, 5 min.; mean ± 2 st. dev., 2 min., 30 sec. to 10 min. The values after placebo were: mean, 5 min., 30 sec.; mean ± 2 st. dev., 2 min., 30 sec. to 11 min. The values after aspirin were: mean, 9 min., 30 sec.; mean ± 2 st. dev., 4 min. to 21 min. The difference between the mean bleeding time after placebo and after aspirin was highly significant (p < 0.001). The distribution of the bleeding times after aspirin suggested that normal subjects do not respond to aspirin as a single population. The degree of prolongation of the bleeding time and the large size of the drops of blood observed in some subjects suggested to us that small amounts of aspirin may exert a significant effect upon hemostasis in normal individuals.

Compliance of the chest wall in chronic bronchitis and emphysema

1963 ◽  
Vol 18 (4) ◽  
pp. 707-711 ◽  
Author(s):  
R. M. Cherniack ◽  
A. Hodson
Keyword(s):  
Airway Obstruction ◽  
Chronic Bronchitis ◽  
Chest Wall ◽  
Respiratory System ◽  
Vital Capacity ◽  
Normal Subjects ◽  
Chest Wall Compliance ◽  
Paradoxical Finding ◽  
Wall Compliance ◽  
Work Done

The respiratory rate was found to be faster and the tidal volume lower than normal in patients with chronic bronchitis and emphysema. The compliance of the total respiratory system, the lungs, and the chest wall was measured in 11 normal subjects and 13 patients with chronic bronchitis, 11 of whom had also developed emphysema. The compliance of the total respiratory system was lower than in the normals in the patients with chronic bronchitis. This was entirely attributable to a reduction in the compliance of the chest wall, that of the lungs being similar to that of the normals. The vital capacity appeared to be related to the compliance of the total respiratory system and was reduced in the patients with chronic bronchitis and emphysema largely because of a diminished distensibility of the chest wall. It is suggested that the low chest wall compliance may explain the paradoxical finding of rapid shallow respirations in these patients with airway obstruction who theoretically would have been expected to breathe slowly and deeply. It is further suggested that the diminished distensibility of the chest wall in patients with chronic bronchitis and emphysema would necessitate an increase in the amount of work done in order to breathe and, therefore, likely contributes to the disability in this disease. Submitted on April 18, 1962

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.

Chest wall interrupter resistance in anesthetized paralyzed humans

1994 ◽  
Vol 77 (2) ◽  
pp. 883-887 ◽  
Author(s):  
E. D'Angelo ◽  
E. Prandi ◽  
M. Tavola ◽  
E. Calderini ◽  
J. Milic-Emili
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Normal Subjects ◽  
Closing Time ◽  
Rapid Fall ◽  
Volume Range ◽  
Inflation Volume

Tracheal (Ptr) and esophageal (Pes) pressure and flow were measured in 12 supine anesthetized paralyzed normal subjects aged 16–22 yr. The subjects were ventilated with a fixed inflation volume (range 0.57–0.62 liter) and with different constant flows ranging between 0.24 and 1.12 l/s. A rapid airway shutter (closing time 10–15 ms) was used to briefly occlude (0.4–0.9) the airways at end inspiration for 33–44 consecutive breaths. At each flow level, Ptr and Pes records obtained during end-inspiratory occlusions were ensemble averaged to allow for the cardiac artifacts. The interrupter resistances of the chest wall and respiratory system were assessed as the rapid fall in Pes and Ptr with occlusion divided by the flow preceding the occlusion. Interrupter resistances of both the chest wall and lung were independent of flow and averaged 0.4 +/- 0.1 and 1.5 +/- 0.4 (SD) cmH2O.s.l–1, respectively. The contribution of the chest wall to the total interrupter resistance was approximately 27% at flows < or = 1 l/s.

scholarly journals Respiratory mechanical effects of surgical pneumoperitoneum in humans

2014 ◽  
Vol 117 (9) ◽  
pp. 1074-1079 ◽  
Author(s):  
Stephen H. Loring ◽  
Negin Behazin ◽  
Aileen Novero ◽  
Victor Novack ◽  
Stephanie B. Jones ◽  
...  
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Transpulmonary Pressure ◽  
Esophageal Pressure ◽  
Pleural Pressure ◽  
Abdominal Pressure ◽  
Positive End Expiratory Pressure ◽  
Before And After ◽  
Show Evidence ◽  
Obese Subjects

Pneumoperitoneum for laparoscopic surgery is known to stiffen the chest wall and respiratory system, but its effects on resting pleural pressure in humans are unknown. We hypothesized that pneumoperitoneum would raise abdominal pressure, push the diaphragm into the thorax, raise pleural pressure, and squeeze the lung, which would become stiffer at low volumes as in severe obesity. Nineteen predominantly obese laparoscopic patients without pulmonary disease were studied supine (level), under neuromuscular blockade, before and after insufflation of CO2 to a gas pressure of 20 cmH2O. Esophageal pressure (Pes) and airway pressure (Pao) were measured to estimate pleural pressure and transpulmonary pressure (Pl = Pao − Pes). Changes in relaxation volume (Vrel, at Pao = 0) were estimated from changes in expiratory reserve volume, the volume extracted between Vrel, and the volume at Pao = −25 cmH2O. Inflation pressure-volume (Pao-Vl) curves from Vrel were assessed for evidence of lung compression due to high Pl. Respiratory mechanics were measured during ventilation with a positive end-expiratory pressure of 0 and 7 cmH2O. Pneumoperitoneum stiffened the chest wall and the respiratory system (increased elastance), but did not stiffen the lung, and positive end-expiratory pressure reduced Ecw during pneumoperitoneum. Contrary to our expectations, pneumoperitoneum at Vrel did not significantly change Pes [8.7 (3.4) to 7.6 (3.2) cmH2O; means (SD)] or expiratory reserve volume [183 (142) to 155 (114) ml]. The inflation Pao-Vl curve above Vrel did not show evidence of increased lung compression with pneumoperitoneum. These results in predominantly obese subjects can be explained by the inspiratory effects of abdominal pressure on the rib cage.

Determinants of increased energy cost of submaximal exercise in obese subjects

1984 ◽  
Vol 56 (1) ◽  
pp. 18-23 ◽  
Author(s):  
B. Anton-Kuchly ◽  
P. Roger ◽  
P. Varene
Keyword(s):  
Energy Cost ◽  
Work Of Breathing ◽  
Mechanical Efficiency ◽  
Anthropometric Data ◽  
External Work ◽  
Lean Control ◽  
Obese Subjects ◽  
Leg Movement ◽  
The Difference ◽  
Pedaling Frequency

The energy cost of submaximal cycling exercises is studied in 23 obese (OS) and 13 lean control (LS) subjects at 1) a constant pedaling frequency (60 rpm) and at various work loads [external work loads (Wmec) up to 100 W] for one group of OS and LS, and at 2) constant Wmec (brake free and 60 or 70 W) and various frequencies (38–70 rpm) for a second group of OS and LS. The total energy expenditure (WO2) is calculated from O2 consumption (VO2) measured in both conditions and is compared with anthropometric data. The results show that at rest or at the same Wmec, WO2 is always greater in OS than in LS. At rest the quotients of WO2 over body surface area are not significantly different. At work the difference in WO2 cannot be explained by the muscular mechanical efficiency, which is not statistically different in OS (26 +/- 7.8%) and LS (25 +/- 4.6%). The calculated increase in the work of breathing of OS can account only for 5–15% of the energy overexpenditure. The energy cost of leg movement is estimated in brake-free cycling trials; it is significantly greater in OS than in LS (118 J compared with 68 J/pedal stroke), but when divided by leg volume the figures are not different (9.2 compared with 8.5 J X dm-3 X pedal stroke-1). Leg moving may account for approximately 60–70% of the energy cost of moderate exercise in cycling OS. The remaining difference in WO2 between OS and LS (20–30%) may be explained by an increase in muscular postural activity related to the lack of physical training of OS.

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