Alveolar liquid pressures in newborn and adult rabbit lungs

1988 ◽  
Vol 64 (4) ◽  
pp. 1629-1635 ◽  
Author(s):  
C. D. Fike ◽  
S. J. Lai-Fook ◽  
R. D. Bland
Keyword(s):  
Airway Pressure ◽  
Transpulmonary Pressure ◽  
Dry Weight ◽  
Adult Rabbit ◽  
Liquid Pressure ◽  
Lung Maturation ◽  
Lung Inflation ◽  
Lung Deflation ◽  
Isolated Lungs ◽  
Alveolar Liquid

To study the effects of lung maturation and inflation on alveolar liquid pressures, we isolated lungs from adult and newborn rabbit pups (1-11 days old). We used the micropuncture technique to measure alveolar liquid pressure at several transpulmonary pressures on lung deflation. Alveolar liquid pressure was greater than pleural pressure but less than airway pressure at all transpulmonary pressures. Alveolar liquid pressure decreased further below airway pressure with lung inflation. At high transpulmonary pressure, alveolar liquid pressure was less in newborn than in adult lungs. To study the effects of edema, we measured alveolar liquid pressures in newborn lungs with different wet-to-dry weight ratios. Alveolar liquid pressure increased with progressive edema. In addition, we compared alveolar liquid and perivenular interstitial pressures in perfused newborn lungs and found that they were similar. Thus alveolar liquid pressure can be used to estimate perivenular interstitial pressure. We conclude that the transvascular pressure gradient for fluid flux into the interstitium might increase with lung inflation and decrease with progressive edema. Furthermore, this gradient might be greater in newborn than adult lungs at high inflation pressures.

Alveolar liquid pressure measured by micropipettes in isolated dog lung

1982 ◽  
Vol 53 (3) ◽  
pp. 737-743 ◽  
Author(s):  
S. J. Lai-Fook ◽  
K. C. Beck
Keyword(s):  
Interstitial Fluid ◽  
Total Lung Capacity ◽  
Fluid Pressure ◽  
Transpulmonary Pressure ◽  
Initial Weight ◽  
Liquid Pressure ◽  
Lung Inflation ◽  
Main Determinant ◽  
Lung Capacity ◽  
Alveolar Surface

Micropipettes (2–5 microns), in conjunction with a servo-nulling system, were used to measure liquid pressure (Pliq) in subpleural alveoli of lobes of dog lungs made edematous by perfusing with plasma to a constant extravascular weight gain (W). Pliq was measured at fixed transpulmonary pressure (Ptp) in lungs whose W was more than 0.5 that of the initial weight (Wi). In six lobes at W/Wi = 0.6, Pliq, relative to alveolar pressure (Palv), was -2.6 +/- 0.4 cmH2O (mean +/- SE), -11.8 +/- 0.6, and -17.5 +/- 1.7 at deflation Ptp values of 5, 15, and 25 cmH2O, respectively. The Pliq increased to -2, -7, and -13.7, respectively, at W/Wi = 2.8. Based on a mean alveolar radius of 50 micron at Ptp at 25 cmH2O and values of Palv - Pliq, values for alveolar surface tension (tau) at W/Wi = 0.6 were 6, 30, and 44 dyn/cm at Ptp of 5, 15, and 25 cmH2O, respectively. In five other lobes at W/Wi = 0.5 and at 65 and 84% total lung capacity, tau was much higher on lung inflation than on deflation. If pericapillary interstitial fluid pressure (Pi) and Pliq were identical under edematous conditions, tau would be the main determinant of Pi.

Alveolar liquid pressure in excised edematous dog lung with increased static recoil

1983 ◽  
Vol 55 (4) ◽  
pp. 1277-1283 ◽  
Author(s):  
K. C. Beck ◽  
S. J. Lai-Fook
Keyword(s):  
Fluid Pressure ◽  
Transpulmonary Pressure ◽  
Measuring System ◽  
Radius Of Curvature ◽  
Liquid Pressure ◽  
Extravascular Fluid ◽  
Air Liquid Interface ◽  
Triton X ◽  
Uniform Expansion ◽  
Alveolar Liquid

Alveolar liquid pressure (Pliq) was measured by micropipettes in conjunction with a servo-nulling pressure measuring system in isolated air-inflated edematous dog lungs. Pliq was measured in lungs either washed with a detergent (0.01% Triton X-100) or subjected to refrigeration for 2-3 days followed by ventilation for 3 h. At 55% of total lung capacity (TLC, the volume at a transpulmonary pressure (Ptp) of 25 cmH2O before treatment), in both the Triton-washed and the ventilated lung, Ptp increased from 5 to 11 cmH2O, whereas Pliq, decreased from -3 to -11 cmH2O relative to alveolar air pressure. Similar increases in Ptp and decreases in Pliq were obtained at higher lung volumes. Alveolar surface tension (T) was estimated from the Laplace equation for a spherical air-liquid interface, assuming that the radius of curvature varies as (volume)n, for -1/3 less than n less than 1/3. For uniform expansion of alveoli (n = 1/3), estimated T was 6 and 18 dyn/cm at 55 and 85% TLC, respectively, before treatment and increased to 23 and 40 dyn/cm following either Triton washing or ventilation. If pericapillary interstitial fluid pressure (Pi) equaled Pliq in edematous lungs, increases in T might reduce Pi and increase extravascular fluid accumulation in lungs made stiff by either Triton washing or cooling and ventilation using large tidal volumes.

Flow and volume dependence of expiratory resistance in anesthetized cats

1989 ◽  
Vol 67 (3) ◽  
pp. 1013-1019 ◽  
Author(s):  
M. Skaburskis ◽  
F. Shardonofsky ◽  
J. Milic-Emili
Keyword(s):  
Respiratory System ◽  
Volume Flow ◽  
Flow Profile ◽  
Pressure Flow ◽  
Lung Inflation ◽  
Mechanically Ventilated ◽  
Volume Dependence ◽  
Flow Dependence ◽  
Lung Deflation ◽  
Respiratory Muscle Activity

In five anesthetized paralyzed cats, mechanically ventilated with tidal volumes of 36–48 ml, the isovolume pressure-flow relationships of the lung and respiratory system were studied. The expiratory pressure was altered between 3 and -12 cmH2O for single tidal expirations. Isovolume pressure-flow plots for three lung volumes showed that the resistive pressure-flow relationships were curvilinear in all cases, fitting Rohrer's equation: P = K1V + K2V2, where P is the resistive pressure loss, K1 and K2 are Rohrer's coefficients, and V is flow. Values of K1 and K2 declined with lung inflation, consistent with the volume dependence of pulmonary (RL) and respiratory system resistances (Rrs). During lung deflation against atmospheric pressure, RL and Rrs tended to remain constant through most of expiration, resulting in a nearly linear volume-flow relationship. In the presence of a fixed respiratory system elastance, the shape of the volume-flow profile depended on the balance between the volume and the flow dependence of RL and Rrs. However, the flow dependence of RL and Rrs indicates that their measured values will be affected by all factors that modify expiratory flow, e.g., respiratory system elastance, equipment resistance, and the presence of respiratory muscle activity.

Alveolar liquid pressure measured in the intact rabbit chest by micropuncture

1993 ◽  
Vol 75 (4) ◽  
pp. 1525-1528 ◽  
Author(s):  
S. Ganesan ◽  
S. J. Lai-Fook
Keyword(s):  
Ambient Pressure ◽  
Lateral Position ◽  
Measuring System ◽  
Parietal Pleura ◽  
Liquid Pressure ◽  
Left Lateral Position ◽  
Isolated Lung ◽  
Residual Capacity ◽  
Alveolar Liquid

Previous measurements in isolated lung showed that alveolar liquid pressure was near the pleural pressure at a lung volume near functional residual capacity (FRC). In this study we verified that alveolar liquid pressure in vivo was similar to that of the isolated lung. In anesthetized paralyzed rabbits (3#x2013;4 kg, n = 9) ventilated with 100% O2 in the left lateral position, we made a pleural window between the fifth and sixth ribs near midchest by removing tissue down to the parietal pleura. Window height was 6 cm above the base of the lung. During apnea, alveolar liquid and pleural pressures were measured by puncturing through the pleural window with micropipettes connected to a servo-nulling pressure-measuring system. Pressures were measured at airway pressures of 0 (FRC) and 10 cmH2O both in vivo and postmortem. In vivo, alveolar liquid and pleural pressures relative to ambient pressure averaged -2.3 +/- 1.4 (SD) and -1.8 +/- 0.9 cmH2O at FRC and increased to 3.3 +/- 1.8 and 1.8 +/- 1.6 cmH2O after inflation to an airway pressure of 10 cmH2O, respectively. Similar values were obtained postmortem. These results were similar to previous measurements in the isolated lung.

Effect of lung inflation on lung blood volume and pulmonary venous flow

1985 ◽  
Vol 58 (3) ◽  
pp. 954-963 ◽  
Author(s):  
R. Brower ◽  
R. A. Wise ◽  
C. Hassapoyannes ◽  
B. Bromberger-Barnea ◽  
S. Permutt
Keyword(s):  
Blood Volume ◽  
Transpulmonary Pressure ◽  
Left Ventricular ◽  
Respiratory Cycle ◽  
Pulmonary Vasculature ◽  
Venous Flow ◽  
Lung Inflation ◽  
Pulmonary Venous Flow ◽  
Respiratory Wave ◽  
Left Ventricular Preload

Phasic changes in lung blood volume (LBV) during the respiratory cycle may play an important role in the genesis of the respiratory wave in arterial pressure, or pulsus paradoxus. To better understand the effects of lung inflation on LBV, we studied the effect of changes in transpulmonary pressure (delta Ptp) on pulmonary venous flow (Qv) in eight isolated canine lungs with constant inflow. Inflation when the zone 2 condition was predominant resulted in transient decreases in Qv associated with increases in LBV. In contrast, inflation when the zone 3 condition was predominant resulted in transient increases in Qv associated with decreases in LBV. These findings are consistent with a model of the pulmonary vasculature that consists of alveolar and extra-alveolar vessels. Blood may be expelled from alveolar vessels but is retained in extra-alveolar vessels with each inflation. The net effect on LBV and thus on Qv is dependent on the zone conditions that predominate during inflation, with alveolar or extra-alveolar effects being greater when the zone 3 or zone 2 conditions predominate, respectively. Lung inflation may therefore result in either transiently augmented or diminished Qv. Phasic changes in left ventricular preload may therefore depend on the zone conditions of the lungs during the respiratory cycle. This may be an important modulator of respiratory variations in cardiac output and blood pressure.

Dynamic lung compliance in newborn and adult cats

1986 ◽  
Vol 60 (3) ◽  
pp. 743-750 ◽  
Author(s):  
K. J. Sullivan ◽  
J. P. Mortola
Keyword(s):  
Stress Relaxation ◽  
Transpulmonary Pressure ◽  
Lung Compliance ◽  
Theoretical Treatment ◽  
The Difference ◽  
Adult Cats ◽  
Isolated Lungs ◽  
Dynamic Lung Compliance ◽  
Volume History ◽  
Lung Stress

Static (Cstat) and dynamic (Cdyn) lung compliance and lung stress relaxation were examined in isolated lungs of newborn kittens and adult cats. Cstat was determined by increasing volume in increments and recording the corresponding change in pressure; Cdyn was calculated as the ratio of the changes in volume to transpulmonary pressure between points of zero flow at ventilation frequencies between 10 and 110 cycles/min. Lung volume history, end-inflation volume, and end-deflation pressure were maintained constant. At the lowest frequency of ventilation, Cdyn was less than Cstat, the difference being greater in newborns. Between 20 and 100 cycles/min, Cdyn of the newborn lung remained constant, whereas Cdyn of the adult lung decreased after 60 cycles/min. At all frequencies, the rate of stress relaxation, measured as the decay in transpulmonary pressure during maintained inflation, was greater in newborns than in adults. The frequency response of Cdyn in kittens, together with the relatively greater rate of stress relaxation, suggests that viscoelasticity contributes more to the dynamic stiffening of the lung in newborns than in adults. A theoretical treatment of the data based on a linear model of viscoelasticity supports this conclusion.

High lung volume increases stress failure in pulmonary capillaries

1992 ◽  
Vol 73 (1) ◽  
pp. 123-133 ◽  
Author(s):  
Z. Fu ◽  
M. L. Costello ◽  
K. Tsukimoto ◽  
R. Prediletto ◽  
A. R. Elliott ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Lung Volume ◽  
Autologous Blood ◽  
Physiological Mechanism ◽  
Transpulmonary Pressure ◽  
Lung Volumes ◽  
Lung Inflation ◽  
Pulmonary Capillaries ◽  
Scanning Electron

We previously showed that when pulmonary capillaries in anesthetized rabbits are exposed to a transmural pressure (Ptm) of approximately 40 mmHg, stress failure of the walls occurs with disruption of the capillary endothelium, alveolar epithelium, or sometimes all layers. The present study was designed to test whether stress failure occurred more frequently at high than at low lung volumes for the same Ptm. Lungs of anesthetized rabbits were inflated to a transpulmonary pressure of 20 cmH2O, perfused with autologous blood at 32.5 or 2.5 cmH2O Ptm, and fixed by intravascular perfusion. Samples were examined by both transmission and scanning electron microscopy. The results were compared with those of a previous study in which the lung was inflated to a transpulmonary pressure of 5 cmH2O. There was a large increase in the frequency of stress failure of the capillary walls at the higher lung volume. For example, at 32.5 cmH2O Ptm, the number of endothelial breaks per millimeter cell lining was 7.1 +/- 2.2 at the high lung volume compared with 0.7 +/- 0.4 at the low lung volume. The corresponding values for epithelium were 8.5 +/- 1.6 and 0.9 +/- 0.6. Both differences were significant (P less than 0.05). At 52.5 cmH2O Ptm, the results for endothelium were 20.7 +/- 7.6 (high volume) and 7.1 +/- 2.1 (low volume), and the corresponding results for epithelium were 32.8 +/- 11.9 and 11.4 +/- 3.7. At 32.5 cmH2O Ptm, the thickness of the blood-gas barrier was greater at the higher lung volume, consistent with the development of more interstitial edema. Ballooning of the epithelium caused by accumulation of edema fluid between the epithelial cell and its basement membrane was seen at 32.5 and 52.5 cmH2O Ptm. At high lung volume, the breaks tended to be narrower and fewer were oriented perpendicular to the axis of the pulmonary capillaries than at low lung volumes. Transmission and scanning electron microscopy measurements agreed well. Our findings provide a physiological mechanism for other studies showing increased capillary permeability at high states of lung inflation.

scholarly journals An assessment of esophageal balloon use for the titration of airway pressure release ventilation and controlled mechanical ventilation in a patient with extrapulmonary acute respiratory distress syndrome: a case report

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Óscar Arellano-Pérez ◽  
Felipe Castillo Merino ◽  
Roberto Torres-Tejeiro ◽  
Sebastián Ugarte Ubiergo
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Airway Pressure ◽  
Distress Syndrome ◽  
Transpulmonary Pressure ◽  
Airway Pressure Release Ventilation ◽  
Pressure Release ◽  
Esophageal Balloon ◽  
Pressure Release Ventilation

Abstract Background Esophageal pressure measurement is a minimally invasive monitoring process that assesses respiratory mechanics in patients with acute respiratory distress syndrome. Airway pressure release ventilation is a relatively new positive pressure ventilation modality, characterized by a series of advantages in patients with acute respiratory distress syndrome. Case presentation We report a case of a 55-year-old chilean female, with preexisting hypertension and recurrent renal colic who entered the cardiosurgical intensive care unit with signs and symptoms of urinary sepsis secondary to a right-sided obstructive urolithiasis. At the time of admission, the patient showed signs of urinary sepsis, a poor overall condition, hemodynamic instability, tachycardia, hypotension, and needed vasoactive drugs. Initially the patient was treated with volume control ventilation. Then, ventilation was with conventional ventilation parameters described by the Acute Respiratory Distress Syndrome Network. However, hemodynamic complications led to reduced airway pressure. Later she presented intraabdominal hypertension that compromised the oxygen supply and her ventilation management. Considering these records, an esophageal manometry was used to measure distending lung pressure, that is, transpulmonary pressure, to protect lungs. Initial use of the esophageal balloon was in a volume-controlled modality (deep sedation), which allowed the medical team to perform inspiratory and expiratory pause maneuvers to monitor transpulmonary plateau pressure as a substitute for pulmonary distension and expiratory pause and determine transpulmonary positive end-expiratory pressure. On the third day of mechanical respiration, the modality was switched to airway pressure release ventilation. The use of airway pressure release ventilation was associated with reduced hemodynamic complications and kept transpulmonary pressure between 0 and 20 cmH2O despite a sustained high positive end-expiratory pressure of 20 cmH2O. Conclusion The application of this technique is shown in airway pressure release ventilation with spontaneous ventilation, which is then compared with a controlled modality that requires a lesser number of sedative doses and vasoactive drugs, without altering the criteria for lung protection as guided by esophageal manometry.

Lung inflation: effects on heart rate, respiration, and vagal afferent activity in seals

1981 ◽  
Vol 240 (2) ◽  
pp. H190-H198 ◽  
Author(s):  
J. E. Angell-James ◽  
R. Elsner ◽  
M. De Burgh Daly
Keyword(s):  
Transpulmonary Pressure ◽  
Harbor Seal ◽  
Nerve Fibers ◽  
Cardiac Response ◽  
Impulse Frequency ◽  
Lung Inflation ◽  
Afferent Nerve Fibers ◽  
Close Relationship ◽  
Vagal Afferent ◽  
Carotid Body Chemoreceptors

In the anesthetized harbor seal, Phoca vitulina, the Hering-Breuer inflation reflex was weak and comparable to that in humans. Single inflations of the lungs from a syringe during the expiratory phase of normal breathing caused temporary inhibition of breathing and an immediate tachycardia dependent on the integrity of the cervical vagosympathetic nerves. A similar cardiac response occurred when the lungs were artificially inflated during an experimental dive and under conditions in which apnea and bradycardia were reflexly induced by a combination of stimulation of the carotid body chemoreceptors and of the trigeminal or laryngeal input. Recordings from single vagal afferent nerve fibers innervating presumptive pulmonary stretch receptors showed a close relationship between the increase in impulse frequency and increase in lung volume or transpulmonary pressure. It appears that in diving the decrease in pulmonary stretch receptor activity during apnea, combined with cessation of central inspiratory neuronal drive, is an important integrative mechanism that helps development of the reflex bradycardia of trigeminal, carotid, chemoreceptor, and baroreceptor origin.

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