Effects of vagotomy on respiratory mechanics in newborn and adult pigs

1986 ◽  
Vol 60 (6) ◽  
pp. 1992-1999 ◽  
Author(s):  
M. G. Clement ◽  
J. P. Mortola ◽  
M. Albertini ◽  
G. Aguggini
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Respiratory Mechanics ◽  
Breathing Patterns ◽  
External Work ◽  
Vagal Control ◽  
Before And After ◽  
Wall Compliance ◽  
Bilateral Vagotomy ◽  
System Time

We have examined breathing patterns and respiratory mechanics in anesthetized tracheostomized newborn piglets and adult pigs and the changes determined by cervical bilateral vagotomy. Piglets had a respiratory system compliance and resistance, on a per kilogram basis, respectively, higher and smaller than the adults. After vagotomy neither variable changed in the newborn, but resistance dropped in the adult. This may suggest that efferent vagal control of bronchomotor tone is more pronounced in the adult. Respiratory system time constant was longer in newborns both before and after vagotomy. The distortion of the chest wall, examined as the ratio between the volume inhaled spontaneously and the passive volume for the same abdominal motion, was more marked in newborns, reflecting their higher chest wall compliance. The work per minute, computed from the pressure and volume changes, was larger in piglets. After vagotomy the external work per minute was not different; however, the larger tidal volumes were accompanied by a larger chest distortion. This may indicate that vagal control of the breathing pattern, by limiting the depth of inspiration and hence the amount of chest distortion, has implications on the energetics of breathing.

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.

Low-frequency respiratory mechanical impedance in the rat

1987 ◽  
Vol 63 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Z. Hantos ◽  
B. Daroczy ◽  
B. Suki ◽  
S. Nagy
Keyword(s):  
Frequency Dependence ◽  
Chest Wall ◽  
Low Frequency ◽  
Mechanical Impedance ◽  
Total Resistance ◽  
Low Frequencies ◽  
Chest Wall Compliance ◽  
Before And After ◽  
Airway Opening ◽  
Wall Compliance

modified forced oscillatory technique was used to determine the respiratory mechanical impedances in anesthetized, paralyzed rats between 0.25 and 10 Hz. From the total respiratory (Zrs) and pulmonary impedance (ZL), measured with pseudorandom oscillations applied at the airway opening before and after thoracotomy, respectively, the chest wall impedance (ZW) was calculated as ZW = Zrs - ZL. The pulmonary (RL) and chest wall resistances were both markedly frequency dependent: between 0.25 and 2 Hz they contributed equally to the total resistance falling from 81.4 +/- 18.3 (SD) at 0.25 Hz to 27.1 +/- 1.7 kPa.l–1 X s at 2 Hz. The pulmonary compliance (CL) decreased mildly, from 2.78 +/- 0.44 at 0.25 Hz to 2.36 +/- 0.39 ml/kPa at 2 Hz, and then increased at higher frequencies, whereas the chest wall compliance declined monotonously from 4.19 +/- 0.88 at 0.25 Hz to 1.93 +/- 0.14 ml/kPa at 10 Hz. Although the frequency dependence of ZW can be interpreted on the basis of parallel inhomogeneities alone, the sharp fall in RL together with the relatively constant CL suggests that at low frequencies significant losses are imposed by the non-Newtonian resistive properties of the lung tissue.

Developmental changes in chest wall compliance in infancy and early childhood

1995 ◽  
Vol 78 (1) ◽  
pp. 179-184 ◽  
Author(s):  
C. Papastamelos ◽  
H. B. Panitch ◽  
S. E. England ◽  
J. L. Allen
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Respiratory Muscles ◽  
Lung Compliance ◽  
Developmental Changes ◽  
System Function ◽  
Manual Ventilation ◽  
Chest Wall Compliance ◽  
Wall Stiffness ◽  
Wall Compliance

Development of chest wall stiffness between infancy and adulthood has important consequences for respiratory system function. To test the hypothesis that there is substantial stiffening of the chest wall in the first few years of life, we measured passive chest wall compliance (Cw) in 40 sedated humans 2 wk-3.5 yr old. Respiratory muscles were relaxed with manual ventilation applied during the Mead-Whittenberger technique. Respiratory system compliance (Crs) and lung compliance (Cl) were calculated from airway opening pressure, transpulmonary pressure, and tidal volume. Cw was calculated as 1/Cw = 1/Crs - 1/Cl during manual ventilation. Mean Cw per kilogram in infants < 1 yr old was significantly higher than that in children > 1 yr old (2.80 +/- 0.87 vs. 2.04 +/- 0.51 ml.cmH2O–1.kg-1; P = 0.002). There was an inverse linear relationship between age and mean Cw per kilogram (r = -0.495, slope -0.037; P < 0.001). In subjects with normal Cl during spontaneous breathing, Cw/spontaneous Cl was 2.86 +/- 1.06 in infants < 1 yr old and 1.33 +/- 0.36 in older children (P = 0.005). We conclude that in infancy the chest wall is nearly three times as compliant as the lung and that by the 2nd year of life chest wall stiffness increases to the point that the chest wall and lung are nearly equally compliant, as in adulthood. Stiffening of the chest wall may play a major role in developmental changes in respiratory system function such as the ability to passively maintain resting lung volume and improved ventilatory efficiency afforded by reduced rib cage distortion.

Respiratory system compliance and resistance in the critically ill

2016 ◽  
Author(s):  
Ricardo Luiz Cordioli ◽  
Laurent Brochard
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Gas Flow ◽  
Respiratory Mechanics ◽  
Volume Ratio ◽  
Plateau Pressure ◽  
Volume Controlled Ventilation ◽  
Ventilation Monitoring ◽  
Resistive Forces ◽  
Pressure Resistance

Under mechanical ventilation, monitoring of respiratory mechanics is fundamental, especially in patients with abnormal mechanics. In order to appropriately set the ventilator, clinicians need to understand the relationship between pressure, volume and flow. To move air in and out the thorax, energy must be dissipated against elastic and resistive forces. Elastance is the pressure to volume ratio and necessitates an end inspiratory occlusion to measure the so-called plateau pressure. Resistance is the ratio between pressure dissipated and mean gas flow. Finally, the total positive end expiratory pressure must be measured with an end expiratory occlusion. Volume-controlled ventilation is the recommended mode to assess respiratory mechanics of a passive patient. Clinicians must be aware that both chest wall and lung participate in forces imposed by the respiratory system. An oesophageal catheter can estimate pleural pressure, and used to partition the respective role of the lung and the chest wall.

Effects of longitudinal laparotomy on respiratory system, lung, and chest wall mechanics

1992 ◽  
Vol 72 (5) ◽  
pp. 1985-1990 ◽  
Author(s):  
R. L. Santos ◽  
M. A. Santos ◽  
R. S. Sakae ◽  
P. H. Saldiva ◽  
W. A. Zin
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Guinea Pigs ◽  
Inspiratory Flow ◽  
Total Resistance ◽  
Abdominal Incision ◽  
Mechanically Ventilated ◽  
Flow Method ◽  
Chest Wall Mechanics ◽  
Before And After

In six sedated, anesthetized, paralyzed, and mechanically ventilated guinea pigs, total respiratory system (RT,rs), lung, and chest wall resistances and respiratory system (Est,rs), lung, and chest wall (Est,w) elastances were determined before and after longitudinal laparotomy. Furthermore the resistances were also split into their initial and difference components, with the former reflecting the Newtonian resistances and the latter representing the viscoelastic/inhomogeneous pressure dissipations in the system. For such purpose the end-inflation occlusion during constant inspiratory flow method was used. During laparotomy, a statistically significant increase in respiratory system difference resistance (from 0.086 to 0.101 cmH2O.ml-1.s) significantly augmented RT,rs (from 0.157 to 0.167 cmH2O.ml-1.s). The former was entirely secondary to a significant increase in chest wall difference resistance (0.019 to 0.034 cmH2O.ml-1.s), which naturally raised chest wall total resistance (from 0.030 to 0.047 cmH2O.ml-1.s). Est,rs and Est,w also increased (14.7 and 13.1%, respectively) after abdominal incision. It can be concluded that the midline xiphipubic laparotomy accompanied by the bilateral ventrodorsal infracostal incision increases RT,rs as a consequence of augmented chest wall difference resistance and Est,rs as a result of higher Est,w.

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

Forced oscillatory respiratory parameters following papain exposure in dogs

1979 ◽  
Vol 46 (1) ◽  
pp. 61-66 ◽  
Author(s):  
A. G. Haddad ◽  
R. L. Pimmel ◽  
D. D. Scaperoth ◽  
P. A. Bromberg
Keyword(s):  
Chest Wall ◽  
Elastic Properties ◽  
Respiratory Mechanics ◽  
Dynamic Compliance ◽  
Lung Mechanics ◽  
Tidal Breathing ◽  
Impedance Data ◽  
Respiratory Parameters ◽  
Before And After ◽  
Made In

Respiratory mechanics were studied in nine intubated dogs before and after exposure to aerosolized papain under conditions known to produce emphysemalike lesions. Forced oscillatory resistance (RFO), compliance (CFO), and inertance (IFO) were computed from impedance data obtained at transrespiratory pressures of -10, 0 (FRC), +10, and +20 cmHWO. Dynamic compliance during tidal breathing (CTB) was also measured at FRC. After papain exposure CTB and CFO increased by 25% (P less than 0.05) at FRC and at +10 cmH2O. There were no consistent changes in RFO or IFO at FRC. However, RFO showed a greater dependency on transrespiratory pressure, which suggests that the elastic properties of airways may also have been affected by papain. Measurements made in open-chested papain-exposed animals showed that about 17% of total RFO and 20% of total elastance were attributable to the chest wall. Forced oscillatory impedance data are sensitive to experimental changes in lung mechanics and provide useful estimates of standard respiratory parameters.

scholarly journals Relationship between Abdominal Pressure, Pulmonary Compliance, and Cardiac Preload in a Porcine Model

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Joost Wauters ◽  
Piet Claus ◽  
Nathalie Brosens ◽  
Myles McLaughlin ◽  
Greet Hermans ◽  
...  
Keyword(s):  
Chest Wall ◽  
Respiratory System ◽  
Cardiac Preload ◽  
Volume Index ◽  
Abdominal Pressure ◽  
Stroke Index ◽  
Respiratory System Compliance ◽  
Chest Wall Compliance ◽  
End Diastolic Volume ◽  
Wall Compliance

Rationale. Elevated intra-abdominal pressure (IAP) may compromise respiratory and cardiovascular function by abdomino-thoracic pressure transmission. We aimed (1) to study the effects of elevated IAP on pleural pressure, (2) to understand the implications for lung and chest wall compliances and (3) to determine whether volumetric filling parameters may be more accurate than classical pressure-based filling pressures for preload assessment in the setting of elevated IAP.Methods. In eleven pigs, IAP was increased stepwise from 6 to 30 mmHg. Hemodynamic, esophageal, and pulmonary pressures were recorded.Results. 17% (end-expiratory) to 62% (end-inspiratory) of elevated IAP was transmitted to the thoracic compartment. Respiratory system compliance decreased significantly with elevated IAP and chest wall compliance decreased. Central venous and pulmonary wedge pressure increased with increasing IAP and correlated inversely (r=-0.31) with stroke index (SI). Global end-diastolic volume index was unaffected by IAP and correlated best with SI (r=0.52).Conclusions. Increased IAP is transferred to the thoracic compartment and results in a decreased respiratory system compliance due to decreased chest wall compliance. Volumetric filling parameters and transmural filling pressures are clearly superior to classical cardiac filling pressures in the assessment of cardiac preload during elevated IAP.

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.

Effect of pulmonary blood flow on measurements of respiratory mechanics using the interrupter technique

1993 ◽  
Vol 74 (3) ◽  
pp. 1083-1088 ◽  
Author(s):  
N. J. Freezer ◽  
C. J. Lanteri ◽  
P. D. Sly
Keyword(s):  
Blood Flow ◽  
Chest Wall ◽  
Respiratory System ◽  
Left Atrial ◽  
Pulmonary Blood Flow ◽  
Respiratory Mechanics ◽  
Dynamic Compliance ◽  
Left Atrial Pressure ◽  
Conducting Airways ◽  
The Relationship

The relationship between respiratory mechanics, changes in pulmonary blood flow (PBF), pulmonary arterial pressure, and left atrial pressure is unclear. Conventional methods for the measurement of respiratory mechanics model the respiratory system as a single compartment, which may not adequately represent the respiratory system in a diseased state. The interrupter technique models the respiratory system as two compartments, with the "flow resistance" of the conducting airways and chest wall (Raw) considered separately from Pdif, a measure of the viscoelastic properties of the lung and chest wall, together with any pendelluft present. The respiratory mechanics of 15 infants in the first year of life were studied during cardiac catheterization with the use of conventional methods and the interrupter technique. The infants had a PBF-to-systemic blood flow ratio ranging from 0.6 to 4.0:1. The specific dynamic compliance of the respiratory system was not related to the PBF; however, there was a significant relationship between PBF and the total resistance of the respiratory system (Rrs) [analysis of variance (ANOVA) F = 5.69, P < 0.05], Raw (ANOVA, F = 12.30, P < 0.01), and Pdif (ANOVA, F = 3.79, P < 0.05). Rrs increased significantly with an increase in mean left atrial pressure (ANOVA, F = 6.92, P < 0.05); however, dynamic compliance, Raw, and Pdif did not. These results suggest that the relationship between Rrs and PBF is due an increase in the resistive properties of the conducting airways and tissue components.

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