Hypertonic aerosol inhalation does not alter central airway blood flow in dogs

1988 ◽  
Vol 65 (5) ◽  
pp. 1990-1994 ◽  
Author(s):  
D. J. Godden ◽  
E. M. Baile ◽  
M. Okazawa ◽  
P. D. Pare
Keyword(s):  
Blood Flow ◽  
Isotonic Saline ◽  
Base Line ◽  
Humid Air ◽  
Dry Air ◽  
Aerosol Inhalation ◽  
Period 2 ◽  
Anesthetized Dogs ◽  
Flow Changes ◽  
Central Airway

Tracheobronchial blood flow in dogs increases with cold or dry air hyperventilation, possibly as a result of airway drying leading to increased osmolarity of airway surface fluid. This study was designed to examine whether administration of aerosols of various tonicity to alter airway surface fluid osmolarity would induce similar blood flow changes. Tracheobronchial blood flow was measured by the radioactive microsphere technique in six anesthetized dogs ventilated with warm humid air (100% relative humidity) for 15 min (period 1), air containing ultrasonically nebulized saline aerosol (1,711 mosmol/kg) for 3 min (period 2) and 12 min (period 3), and the same aerosol at a higher nebulizer output for a further 3 min (period 4). Between periods 3 and 4, the dogs were ventilated with warm humid air for 30 min to reestablish base-line conditions. In another five dogs, measurements were made after 30 min of ventilation with 1) warm humid air, 2) isotonic saline aerosol, 3) warm humid air, 4) distilled water aerosol (3 dogs), and hypertonic saline aerosol (2 dogs). After the last measurement was made, each dog was killed, the trachea and major bronchi were excised, and blood flow was calculated. No change in blood flow was found during any period of aerosol inhalation. The osmolar load imposed on the airways was estimated and was similar to that occurring during cold or dry air hyperventilation. These data suggest that increasing osmolarity of airway surface fluid does not explain the blood flow changes seen during hyperventilation of cold or dry air.

Effect of cold and warm dry air hyperventilation on canine airway blood flow

1987 ◽  
Vol 62 (2) ◽  
pp. 526-532 ◽  
Author(s):  
E. M. Baile ◽  
R. W. Dahlby ◽  
B. R. Wiggs ◽  
G. H. Parsons ◽  
P. D. Pare
Keyword(s):  
Blood Flow ◽  
Left Lung ◽  
Tissue Temperature ◽  
Humid Air ◽  
Dry Air ◽  
Airway Mucosa ◽  
Anesthetized Dogs ◽  
Tracheal Tissue ◽  
Group 2 ◽  
Central Airway

Tracheobronchial blood flow increases with cold air hyperventilation in the dog. The present study was designed to determine whether the cooling or the drying of the airway mucosa was the principal stimulus for this response. Six anesthetized dogs (group 1) were subjected to four periods of eucapnic hyperventilation for 30 min with warm humid air [100% relative humidity (rh)], cold dry air (-12 degrees C, 0% rh), warm humid air, and warm dry air (43 degrees C, 0% rh). Five minutes before the end of each period of hyperventilation, tracheal and central airway blood flow was determined using four differently labeled 15-micron diam radioactive microspheres. We studied another three dogs (group 2) in which 15- and 50-micron microspheres were injected simultaneously to determine whether there were any arteriovenous communications in the bronchovasculature greater than 15 micron diam. After the last measurements had been made, all dogs were killed, and the lungs, including the trachea, were excised and blood flow to the trachea, left lung bronchi, and parenchyma was calculated. Warm dry air hyperventilation produced a consistently greater increase in tracheobronchial blood flow (P less than 0.01) than cold dry air hyperventilation, despite the fact that there was a smaller fall (6 degrees C) in tracheal tissue temperature during warm dry air hyperventilation than during cold dry air hyperventilation (11 degrees C), suggesting that drying may be a more important stimulus than cold for increasing airway blood flow. In group 2, the 15-micron microspheres accurately reflected the distribution of airway blood flow but did not always give reliable measurements of parenchymal blood flow.

Mechanism for increase in tracheobronchial blood flow induced by hyperventilation of dry air in dogs

1990 ◽  
Vol 68 (1) ◽  
pp. 105-112 ◽  
Author(s):  
E. M. Baile ◽  
D. J. Godden ◽  
P. D. Pare
Keyword(s):  
Blood Flow ◽  
Relative Humidity ◽  
Main Stem ◽  
Constant Infusion ◽  
Humid Air ◽  
Mechanically Ventilated ◽  
Dry Air ◽  
Period 2 ◽  
Group 2 ◽  
Group 1

To test whether the consistent increase in tracheal and bronchial blood flow observed in dogs during hyperventilation of dry air might be the result of release of mediators such as vasodilatory prostaglandins or neuropeptides, we studied two groups of anesthetized mechanically ventilated dogs. Group 1 (n = 6) was hyperventilated for four 30-min periods with 1) warm humid air (38-40 degrees C, 100% relative humidity), 2) warm dry air (38-40 degrees C, 0% relative humidity), 3) warm humid air, and 4) warm dry air. After period 2, a loading dose of indomethacin (4 mg/kg iv) was given over 15 min followed by a constant infusion (4 mg.kg-1.h-1). Group 2 (n = 10) was hyperventilated for four 15- to 20-min periods by use of the protocol described above. After period 3 (group 2a) or period 2 (group 2b), topical 4% lidocaine hydrochloride solution was instilled into the trachea and main stem bronchi. Five minutes before the end of each period of hyperventilation, cardiac output and vascular pressures were measured. To determine airway blood flow, differently labeled radioactive microspheres were injected into the left atrium. After the last measurements, dogs were killed and the lungs excised. Blood flow to the trachea, main stem bronchi, and parenchyma (group 1 only) was calculated. Results showed that hyperventilation of dry air produced a significant increase in blood flow to the trachea and bronchi (period 2). In group 1, this increase was attenuated (P less than 0.02) after administration of indomethacin.(ABSTRACT TRUNCATED AT 250 WORDS)

"Closing volume" changes in alloxan-induced pulmonary edema in anesthetized dogs

1975 ◽  
Vol 39 (2) ◽  
pp. 235-241 ◽  
Author(s):  
R. Lemen ◽  
J. G. Jones ◽  
P. D. Graf ◽  
G. Cowan
Keyword(s):  
Pulmonary Edema ◽  
Control Group ◽  
Closing Volume ◽  
Base Line ◽  
Alveolar Plateau ◽  
Single Breath ◽  
Period 2 ◽  
System Pressure ◽  
Before And After ◽  
Anesthetized Dogs

“Closing volume” (CV) was measured by the single-breath oxygen (SBO2) test in six dogs (alloxan group) before and after alloxan 100–200 mg/kg iv) was injected. CV increased significantly (P less than 0.05) from 32 +/- 3.2% (base line) to 45 +/- 3.5 % in period 1 (0–30 min after alloxan), but vital capacity (VC), respiratory system pressure volume (PV) curves, and alveolar plateau slopes did not change. No radiologic evidence of pulmonary edema was demonstrated in two dogs studied in period 1. CV decreased to 20 +/- 3.9% during period 2 (30–80 min after alloxan) and was associated with tracheal frothing, decreased VC, changes in the PV curve, and alveolar plateau slope, as well as histologic evidence of severe pulmonary edema. CV was 29 +/- 3.0%, and there were no changes in VC, PV curves, or alveolar plateau slopes in 6 other dogs studied for 2 h (control group). CV increased during period 1 before pulmonary edema could be demonstrated by changes in VC, PV curves, or radiography, but in period 2 lung function was so altered that CV by the SBO2 technique gave no useful information.

Effect of autonomic blockade on tracheobronchial blood flow

1987 ◽  
Vol 62 (2) ◽  
pp. 520-525 ◽  
Author(s):  
E. M. Baile ◽  
S. Osborne ◽  
P. D. Pare
Keyword(s):  
Blood Flow ◽  
Blood Gases ◽  
Lung Parenchyma ◽  
Beta Blockade ◽  
Humid Air ◽  
Dry Air ◽  
Arterial Blood ◽  
Autonomic Blockade ◽  
Alpha Blockade ◽  
Group 2

Tracheobronchial blood flow increases two to five times in response to cold and warm dry air hyperventilation in anesthetized tracheostomized dogs. In this series of experiments we have attempted to attenuate this increase by blockade of the autonomic nervous system. Four groups of anesthetized, tracheostomized, open-chest dogs were studied. Group 1 (n = 5) were hyperventilated for 30 min with 1) warm humid [approximately 26 degrees C, 100% relative humidity, (rh)] air followed by bilateral vagotomy, 2) warm humid air, 3) cold (-22 degrees C, 0% rh) dry air, and 4) warm humid air. Groups 2, 3, and 4 (n = 3/group) were hyperventilated for 30 min with 1) warm humid (approximately 41 degrees C, 100% rh) air, 2) warm dry (approximately 41 degrees C) air, 3) warm humid air, and 4) warm dry air. Group 2 were controls. Group 3 were given phentolamine, 0.6 mg/kg intravenously, as an alpha-blockade, and group 4 were given propranolol, 1 mg/kg, as a beta-blockade after warm dry air hyperventilation (period 2). Five minutes before the end of each 30-min period of hyperventilation, measurements of vascular pressures, cardiac output, arterial blood gases, and inspired, body, and tracheal temperatures were measured, and differently labeled radioactive microspheres were injected into the left atrium to make separate measurements of airway blood flow. After the last measurements had been made animals were killed and their lungs were excised. Blood flow to the airways and lung parenchyma was calculated.(ABSTRACT TRUNCATED AT 250 WORDS)

Dry air-induced constriction in lung periphery: a canine model of exercise-induced asthma

1985 ◽  
Vol 59 (6) ◽  
pp. 1986-1990 ◽  
Author(s):  
A. N. Freed ◽  
B. Bromberger-Barnea ◽  
H. A. Menkes
Keyword(s):  
Flow Rate ◽  
Exposure Period ◽  
Canine Model ◽  
Base Line ◽  
Dry Air ◽  
Peripheral Airways ◽  
Before And After ◽  
Anesthetized Dogs ◽  
Lung Periphery ◽  
Exercise Induced

We studied the effects of the flow of dry air on collateral tone in the lung periphery. A bronchoscope was wedged in sublobar segments of anesthetized dogs, and measurements of collateral resistance (Rcs) were recorded before and after flow was increased from 200 to 2,000 ml/min for a 5-min period. Five minutes after exposure was completed, Rcs increased by an average of 117 +/- 25.2% (SE) over control. Maximum Rcs occurred 5 min after the challenge was concluded and required 48 +/- 10.5 min to return to base line. When flow rate was held constant and exposure period varied, Rcs increased with increased stimulus duration. With exposure times held constant, the response of the collateral system was positively associated with changes in stimulus strength (flow rate). No refractory period was observed with repetitive challenges. Finally, when dry air (delivered at 22 degrees C) and conditioned air (i.e., delivered at 28 degrees C; relative humidity = 80%) challenges were alternated in the same wedged segment, dry air produced a mean increase in Rcs of 93.2%, whereas challenge with warm moist air increased Rcs only 33.5%. Regardless of which challenge was presented first, dry air consistently produced a greater constrictor response. This response is similar to that observed in cold air- and exercise-induced asthma and indicates that the lung periphery in dogs, like larger airways in asthmatic subjects, has the potential to increase tone when exposed to dry air. Peripheral airways in dogs thus constitute a model that can be used for the investigation of exercise-induced asthma.

Ventilatory responses to intravenous and airway CO2 administration in anesthetized dogs

1980 ◽  
Vol 48 (2) ◽  
pp. 337-346 ◽  
Author(s):  
W. E. Fordyce ◽  
F. S. Grodins
Keyword(s):  
Blood Flow ◽  
Steady State ◽  
Loading Rate ◽  
Blood Flow Rate ◽  
Time Dependent ◽  
Base Line ◽  
Ventilatory Responses ◽  
Significant Difference ◽  
Anesthetized Dogs ◽  
Randomized Protocol

The ventilatory responses to steady-state venous CO2 loading (iv CO2) and CO2 inhalation have been observed in chloralose-urethan-anesthetized dogs. Intravenous CO2 was administered by increasing the CO2 fraction of gas ventilating a membrane gas exchanger in an arteriovenous bypass; blood flow rate was fixed at 30 ml/min. During the study, we identified a time-dependent hyperventilation in all 14 experimentally treated dogs and in 4 additional sham-treated dogs. When we tested 8 of these animals with a protocol having small progressive increments in iv CO2 loading rate, we observed a response approaching isocapnia during iv CO2 and a large hypocapnia when we returned to control conditions. The use of a randomized protocol in 6 animals demonstrated the necessity of accounting for this systematic base-line shift, because before doing so the response depended more on the passage of time than on the nature of the CO2 load. After this analytical adjustment was made, there was no significant difference between the respiratory controller gains (delta nu E/delta Paco2) for inhaled and iv CO2.

Perfusion distribution and lung thermal volume in canine hydrochloric acid aspiration

1988 ◽  
Vol 65 (2) ◽  
pp. 750-759 ◽  
Author(s):  
P. V. Carlile ◽  
S. F. Hagan ◽  
B. A. Gray
Keyword(s):  
Blood Flow ◽  
Lung Injury ◽  
Regional Blood Flow ◽  
Base Line ◽  
Lung Mass ◽  
Acid Aspiration ◽  
Anesthetized Dogs ◽  
Peep Ventilation ◽  
Trapped Lung ◽  
The Right

We investigated the effects of a brief period of positive end-expiratory pressure (PEEP) ventilation or nitroglycerin (NTG) infusion on the distribution of pulmonary blood flow and extravascular thermal volume (ETV) in anesthetized dogs with unilateral HCl lung injury. ETV was determined by the thermal dye technique by use of a monoexponential extrapolation to exclude recirculating indicator, and regional blood flow was determined by a particle distribution technique (radiolabeled plastic microspheres). The lungs were weighted after the animals were killed, and extravascular lung mass (ELM) was determined with the use of hemoglobin to correct for trapped lung blood. Measurements were obtained before instillation of HCl into the right lung and repeated 3 h later before, during, and after PEEP ventilation or NTG infusion. Fractional perfusion of the severely injured portion of the right lung (Qinj/QT) fell from 44.3 +/- 11.1% at base line to 27.8 +/- 15.4% after the onset of lung injury. PEEP produced an acute reversible increase in ETV (63 +/- 37% over average of pre- and post-PEEP values), and the changes in ETV were closely correlated with changes in Qinj/QT (r = 0.91). NTG infusion produced insignificant increases in ETV (14 +/- 10% over average of pre- and postinfusion values) and Qinj/QT (59 +/- 35%), but the changes in ETV and Qinj/QT were strongly correlated (r = 0.92). The fraction of extravascular lung mass detected by the thermodilution measurement averaged 0.44 (range 0.24-0.77).(ABSTRACT TRUNCATED AT 250 WORDS)

Investigation of Blood-Flow Changes During Cognitive Task Activation using CASL

2004 ◽  
Vol 35 (03) ◽  
Author(s):  
T Mildner ◽  
S Zysset ◽  
R Trampel ◽  
W Driesel ◽  
HE Möller
Keyword(s):  
Blood Flow ◽  
Cognitive Task ◽  
Flow Changes ◽  
Task Activation
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