Dynamics of the collateral pathways of canine lungs after flow interruption

1989 ◽  
Vol 67 (3) ◽  
pp. 1213-1219 ◽  
Author(s):  
M. S. Ludwig ◽  
S. Bellofiore ◽  
S. A. Shore ◽  
J. M. Drazen ◽  
J. J. Fredberg
Keyword(s):  
Constant Flow ◽  
Alveolar Pressure ◽  
Time Constants ◽  
Closed Chest ◽  
Pressure Decay ◽  
Flow Interruption ◽  
Open Chest ◽  
Collateral Pathways ◽  
Bronchial Resistance

After interruption of a constant flow (Vcoll) delivered through a bronchoscope into a wedged segment of lung, the pressure at the tip of the bronchoscope (Pb) often decays in a pattern seemingly indicative of two time constants. We tested the hypothesis that the initial more rapid component of the decay is associated with pressure equilibration across the bronchial resistance (Rb), separating bronchoscope tip from alveolus, and that the slower component is associated with pressure equilibration across the collateral pathways separating the wedged segment from surrounding regions. In eight open-chest mongrel dogs, we affixed an alveolar capsule to the segment subtended by the wedged bronchoscope and measured alveolar pressure (PA) and Pb during delivery of Vcoll into the segment and after its sudden interruption. Under both control conditions and after delivery of aerosolized histamine (1.0 or 10 mg/ml), we were unable to demonstrate a gradient between Pb and PA either during constant flow or after flow interruption. Whenever the decay of Pb was not monoexponential, neither was that of PA. Thus there was no evidence of an appreciable Rb, and the rapid component of the decay must be attributable to other factors. In a second protocol, we examined whether behavior departing from monoexponential decay was attributable to the presence of multicompartment behavior within the wedged segment or rather reflected the behavior of a single homogeneous but nonlinear compartment. In five closed-chest dogs, we systematically varied the initial Pb by changing Vcoll and recorded nonexponential pressure decay after flow interruption.(ABSTRACT TRUNCATED AT 250 WORDS)

Juxtacardiac pressure in closed-chest dogs

1986 ◽  
Vol 60 (1) ◽  
pp. 184-190
Author(s):  
H. Sasaki ◽  
K. Shirato ◽  
M. Nakamura ◽  
T. Takishima
Keyword(s):  
Pleural Pressure ◽  
Similar Magnitude ◽  
Alveolar Pressure ◽  
Heart Volume ◽  
Closed Chest ◽  
Open Chest ◽  
Esophageal Balloon ◽  
Balloon Technique

We studied pressure (Ppc)-volume (Vpc) relationships of the pericardial sac by inserting air into it at constant end-diastolic heart volume in six dogs. The lungs were inflated by positive alveolar pressure while pleural pressure was monitored using the esophageal balloon technique. Ppc-Vpc relationships were measured at transpulmonary pressures (PL) of 30, 10, and 5 cmH2O in each of three states: closed chest, open chest with lung separation, and open chest with the pericardium dissected free of its mediastinal attachment. Ppc in the closed-chest condition was more positive than Ppc in the open chest with lung separation, with increase of Vpc and PL, which suggests that the lungs compress the pericardium. Ppc in the open-chest condition with lung separation was also more positive than Ppc in the pericardium after it was dissected free, which suggests that mediastinal attachment compresses the pericardium. It is suggested that lungs in the closed-chest condition as well as mediastinal attachment reduce the heart expansion by a similar magnitude.

A COMPARISON OF OPEN-CHEST AND CLOSED-CHEST CARDIAC MASSAGE IN DOGS

1961 ◽  
Vol 22 (2) ◽  
pp. 280-285 ◽  
Author(s):  
JOSEPH S. REDDING ◽  
RICHARD A. COZINE
Keyword(s):  
Cardiac Massage ◽  
Closed Chest ◽  
Open Chest

Mechanical factors and the regulation of perfusion through atelectatic lung in pigs

1982 ◽  
Vol 52 (3) ◽  
pp. 647-654 ◽  
Author(s):  
S. Enjeti ◽  
P. B. Terry ◽  
H. A. Menkes ◽  
R. J. Traystman
Keyword(s):  
Blood Flow ◽  
Vascular Conductance ◽  
Hemodynamic Responses ◽  
Closed Chest ◽  
Open Chest ◽  
Regional Hemodynamics ◽  
Mechanical Factors

The role of mechanical interdependence in the perfusion of atelectatic lung was studied in two ways: a) regional hemodynamics were compared before (control) and after the development of lobar and sublobar atelectasis, and b) the effect of thoracotomy on regional hemodynamics was assessed. With lobar atelectasis mean lobar blood flow and vascular conductance decreased to 60% of control. Sublobar atelectasis caused mean sublobar blood flow and vascular conductance to decrease to 6% of control. Opening the chest after production of lobar atelectasis caused blood flow to fall to 50% of control. When sublobar atelectasis was produced in the open chest, sublobar blood flow decreased to 25% of control measurements made prior to thoracotomy. We conclude that with a closed chest, sublobar vascular distortion mediated by mechanical interdependence may be an important mechanism responsible for the differences in hemodynamic responses to atelectasis between lobes and sublobar regions.

Invasive hemodynamics and force-frequency relationships in open- versus closed-chest mice

1997 ◽  
Vol 273 (5) ◽  
pp. H2528-H2533 ◽  
Author(s):  
Brian D. Hoit ◽  
Nancy Ball ◽  
Richard A. Walsh
Keyword(s):  
Heart Rate ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Force Frequency ◽  
Closed Chest ◽  
Open Chest ◽  
Systolic And Diastolic Function ◽  
Frequency Relationship ◽  
Maximal Rise ◽  
Open Versus

We compared hemodynamics, ventricular function, and force-frequency relationships in six open-chest and six closed-chest anesthetized mice (FVB/N strain). Left ventricular (LV) pressure was measured with a 1.8- or 1.4-Fr Millar catheter placed via the right carotid artery and the LV apex in the closed- and open-chest state, respectively. Pacing was performed with electrodes placed either directly on atrial appendages (open chest) or with a 1-Fr bipolar catheter via the jugular vein (closed chest). Closed-chest animals had greater spontaneous heart rate (267 ± 106 vs. 147 ± 27 beats/min), LV systolic (81 ± 14 vs. 48 ± 9 mmHg) and diastolic pressures (11.2 ± 4.8 vs. 5.6 ± 2.4 mmHg), and maximal rise (+dP/d t max: 6,208 ± 2,519 vs. 3,682 ± 671 mmHg/s) and fall in pressure development (−dP/d t max: −6,094 ± 2,386 vs. −3,001 ± 399 mmHg/s). LV systolic pressure (98 ± 18 vs. 52 ± 11 mmHg), +dP/d t max (9,240 ± 2,459 vs. 5,777 ± 2,473 mmHg/s), and −dP/d t max(−8,375 ± 2,551 vs. −3,753 ± 1,170 mmHg/s) were significantly higher when animals were matched at a heart rate of 420 beats/min in closed-chest vs. open-chest animals. Biphasic force-frequency relationships were seen in all animals, but the critical heart rate was greater in the closed- than open-chest animals (432 ± 42 vs. 318 ± 42 beats/min). We conclude that 1) there are significant differences between invasive indexes of systolic and diastolic function between the closed- and open-chest preparations, 2) there is a biphasic force-frequency relationship in the anesthetized mouse, and 3) dP/d t max can be used to assess the cardiovascular phenotype.

CARDIAC RESUSCITABILITY AFTER CLOSED–CHEST, MAST AUGMENTED AND OPEN–CHEST CARDIOPULMONARY RESUSCITATION

1981 ◽  
Vol 9 (3) ◽  
pp. 237
Author(s):  
J. Alifimoff ◽  
P. Safar ◽  
N. Bircher W. Stezoski ◽  
R. Barbati
Keyword(s):  
Cardiopulmonary Resuscitation ◽  
Closed Chest ◽  
Open Chest

An extracorporeal shunt for the measurement of coronary flow in the closed-chest dog

1977 ◽  
Vol 233 (1) ◽  
pp. H154-H156
Author(s):  
J. C. Yeager ◽  
J. B. Scott ◽  
F. J. Haddy
Keyword(s):  
Blood Flow ◽  
Coronary Blood Flow ◽  
Coronary Flow ◽  
Constant Pressure ◽  
Electromagnetic Flowmeter ◽  
Constant Flow ◽  
Left Carotid Artery ◽  
Roller Pump ◽  
Closed Chest ◽  
Common Laboratory

An extracorporeal shunt circuit interposed between the left carotid artery and the left coronary ostium employs an electromagnetic flowmeter to measure coronary blood flow in the closed-chest anesthetized dog. Flow may be measured with the animal's arterial pressure as the driving force; introduction of a roller pump, or a roller pump and a negative feedback pressure controller allows for constant flow or constant pressure modes. During occlusion of the circuit or cessation of pump flow, retrograde coronary blood flow can be collected for measurement. The construction of the circuit is relatively simple and inexpensive, using common laboratory materials and a commercially available electromagnetic flowmeter and probe.

Viscoelastic behavior of lung and chest wall in dogs determined by flow interruption

1989 ◽  
Vol 67 (6) ◽  
pp. 2219-2229 ◽  
Author(s):  
T. Similowski ◽  
P. Levy ◽  
C. Corbeil ◽  
M. Albala ◽  
R. Pariente ◽  
...  
Keyword(s):  
Frequency Dependence ◽  
Chest Wall ◽  
Viscoelastic Behavior ◽  
Constant Flow ◽  
Pulmonary Tissue ◽  
Airway Occlusion ◽  
Chest Wall Mechanics ◽  
Flow Interruption ◽  
Overall Resistance ◽  
Pressure Changes

Pulmonary and chest wall mechanics were studied in six anesthetized paralyzed dogs, by use of the technique of rapid airway occlusion during constant flow inflation. Analysis of the pressure changes after flow interruption allowed us to partition the overall resistance of the lung (Rl) and chest wall (Rw) and total respiratory system (Rrs) into two components, one (Rinit) reflecting in the lung airway resistance (Raw), the other (delta R) reflecting primarily the viscoelastic properties of the pulmonary and chest wall tissues. The effects of varying inspiratory flow and inflation volume were interpreted in terms of frequency dependence of resistance, by using a spring-and-dashpot model previously proposed and substantiated by Bates et al. (Proc. 9th Annu. Conf. IEEE Med. Biol. Soc., 1987, vol. 3, p. 1802-1803). We observed that 1) Raw and Rw,init were nearly equal and small relative to Rl and Rw (both were unaffected by flow); 2) Rrs,init decreased slightly with increasing volume; 3) both delta Rl and delta Rw decreased with increasing flow and increased with increasing lung volume. These changes were manifestations of frequency dependence of delta R, as it is predicted by the model; 4) Rrs, Rl, and Rw followed the same trends as delta R. These results corroborate data previously reported in the literature with the use of different techniques to measure airways and pulmonary tissue resistances and confirm that the use of Rl to assess bronchial reactivity is problematic. The interrupter techniques provides a convenient way to obtain Raw values, as well as analogs of lung and chest wall tissue resistances in intact dogs.

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