Ventilatory responses to embolization of lung

1961 ◽  
Vol 16 (3) ◽  
pp. 469-472 ◽  
Author(s):  
John M. Cahill ◽  
Ernst O. Attinger ◽  
John J. Byrne
Keyword(s):  
Flow Resistance ◽  
Lung Compliance ◽  
Significant Rise ◽  
Tidal Range ◽  
Pulmonary Resistance ◽  
Ventilatory Responses ◽  
Significant Fall ◽  
Pulmonary Embolization ◽  
Pulmonary Air Flow ◽  
Spontaneously Breathing

Marked changes in respiratory rate and volume occurred when anesthetized and spontaneously breathing dogs were subjected to pulmonary embolization with barium sulfate. Following embolization, there was a statistically significant fall in lung compliance, and, although a rise in pulmonary air-flow resistance occurred in the majority of instances, this change was not statistically significant. When the dogs were ventilated in approximately the resting tidal range by means of a pump and embolization was carried out, a statistically significant fall in lung compliance as well as a significant rise in pulmonary resistance was seen. Embolization of spontaneously breathing vagotomized animals in three instances revealed a fall in lung compliance and a rise in pulmonary resistance. The experimental observations of others are reviewed and the clinical implications are discussed. Submitted on October 28, 1960

Ventilatory mechanics in hypovolemic shock

1964 ◽  
Vol 19 (4) ◽  
pp. 679-682 ◽  
Author(s):  
John M. Cahill ◽  
John J. Byrne
Keyword(s):  
Blood Pressure ◽  
Flow Resistance ◽  
Air Flow ◽  
Hypovolemic Shock ◽  
Lung Compliance ◽  
Significant Rise ◽  
Mean Blood Pressure ◽  
The Mean ◽  
Ventilatory Mechanics

In order to study ventilatory mechanics in shock, dogs were bled arterially into a reservoir, the height of which was regulated to keep the mean blood pressure of the animal at approximately 30 mm Hg. When the animal “took up” 40% of his maximal shed volume of blood (2–3 hr), the remainder of the blood was reinfused and the animal assumed to be in irreversible shock. Studies throughout the stages of hypovolemic and irreversible shock revealed a significant rise in lung compliance and a fall in combined viscous and air-flow resistance initially if the animal's lungs were carefully inflated prior to each study. As shock continued, there was a tendency for the lung compliance and resistance to air flow to return in the direction of the control values. Submitted on October 29, 1962

Cardiorespiratory effects of rapid saline infusion in normal man

1975 ◽  
Vol 38 (5) ◽  
pp. 786-775 ◽  
Author(s):  
A. L. Muir ◽  
D. C. Flenley ◽  
B. J. Kirby ◽  
M. F. Sudlow ◽  
A. R. Guyatt ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Arterial Pressure ◽  
Pulmonary Arterial Pressure ◽  
Control Period ◽  
Lung Compliance ◽  
Saline Infusion ◽  
Tidal Range ◽  
Closing Volume ◽  
Rapid Infusion ◽  
Pulmonary Arterial

We have studied the cardiorespiratory effects of the rapid infusion (100 ml/min) of 2 liters of saline in four normal seated subjects. Cardiac output and pulmonary arterial pressure increased, while vital capacity (VC) and total lung capacity (TLC) decreased. There was an increase in closing volume (CV) without any detectable change in lung compliance or flow-volume characteristics. There was an increase in Pao2 during infusion period which can be related to better matching of ventilation to perfusion and to improved hemoglobin transport. In the recovery stage as cardiac output, pulmonary arterial pressure, TLC, and VC all returned toward control values CV remained high. In two subjects CV occurred within the normal tidal range of ventilation and in these two subjects Pao2 fell significantly below values obtained in the control period. The results suggest that rapid saline infusion in man can cause interstitial edema and lead to premature airway closure and hypoxemia.

Hyperventilation evoked by activation of the vicinity of the caudal inferior olivary nucleus depends on the fastigial nucleus in anesthetized rats

2008 ◽  
Vol 104 (5) ◽  
pp. 1351-1358 ◽  
Author(s):  
Jianguo Zhuang ◽  
Fadi Xu ◽  
Donald T. Frazier
Keyword(s):  
Electrical Stimulation ◽  
Chemical Activation ◽  
Ibotenic Acid ◽  
Fastigial Nucleus ◽  
Inferior Olivary Nucleus ◽  
Ventilatory Responses ◽  
Respiratory Modulation ◽  
Spontaneously Breathing ◽  
Inferior Olivary ◽  
Olivary Nucleus

Several studies have demonstrated that cerebellar deep nuclei, particularly the rostral fastigial nucleus (FNr), are involved in respiratory modulation. These nuclei receive inputs from the contralateral caudal inferior olivary nuclei of the medulla. The objectives of this study were to determine whether electrical and chemical activation of the vicinity of the caudal inferior olivary nuclei (vIOc) affected respiration and, if true, whether the FNr was involved in the vIOc stimulation-evoked ventilatory responses. Experiments were conducted in 30 anesthetized and spontaneously breathing rats. Our results showed that 1) electrical (25 or 100 μA at 10 or 20 Hz for 10 s) and chemical (1 or 100 mM, 25–50 nl N-methyl-d-aspartate) stimulation of the vIOc augmented ventilation predominantly via increasing tidal volume; 2) the responses to the electrical stimulation were almost eliminated by lesion of the contralateral FNr via microinjection of ibotenic acid; and 3) the respiratory responses to electrical stimulation in the vicinity of the rostral IO were 65–70% smaller compared with that evoked by vIOc stimulation. These findings strongly suggest that vIOc neurons play a significant role in modulation of respiratory activity, largely depending on their projections to the FNr.

Pulmonary mechanics during induced pulmonary edema in anesthetized dogs

1959 ◽  
Vol 14 (2) ◽  
pp. 177-186 ◽  
Author(s):  
C. D. Cook ◽  
J. Mead ◽  
G. L. Schreiner ◽  
N. R. Frank ◽  
J. M. Craig
Keyword(s):  
Pulmonary Edema ◽  
Lung Compliance ◽  
Tidal Range ◽  
Pulmonary Mechanics ◽  
Vascular Congestion ◽  
Anesthetized Dogs ◽  
Trapped Gas ◽  
Aortic Obstruction ◽  
Gas Volume ◽  
Normal Lungs

In order to study the mechanisms underlying the changes in the mechanical properties of the lungs during pulmonary edema, pulmonary vascular congestion was produced in spontaneously breathing, anesthetized dogs by partial aortic obstruction and intravenous infusion. Brief periods of congestion were associated with small changes in the lung compliance compared with the progressive and striking compliance reduction (-78%) noted with more prolonged congestion. Lung volume at end-expiration showed little change if edema fluid and trapped gas as well as the ventilated gas volume were taken into account. When edematous lungs were forcibly inflated beyond the tidal range, it was found that the overall compliance at a distending pressure of 30 cm H2O was not much less (-6%) than that of normal lungs. Furthermore, edematous lungs manifested marked ‘static’ hysteresis during such maneuvers. These findings suggested that surface phenomena were responsible for the mechanical behavior of edematous lungs rather than vascular congestion, per se, or intrinsic tissue changes. This was borne out by experiments on excised lungs which showed that the elastic properties of edematous lungs were not significantly different from normal lungs when surface forces were minimized. Submitted on August 25, 1958

Local control of pulmonary resistance and lung compliance in the canine lung

1975 ◽  
Vol 39 (4) ◽  
pp. 580-589 ◽  
Author(s):  
R. L. Coon ◽  
C. C. Rattenborg ◽  
J. P. Kampine
Keyword(s):  
Pulmonary Artery ◽  
Local Control ◽  
Vagal Stimulation ◽  
Lower Lobe ◽  
Lung Compliance ◽  
Artery Occlusion ◽  
Pulmonary Resistance ◽  
Acid Infusion ◽  
Acid Base Status

Local control of pulmonary resistance and lung compliance was studied in the in situ left lower lobe of the canine lung. Recirculation of blood through the lobe while the Pco2 of the ventilatory gas was varied resulted in an increase in resistance and a decrease in compliance only when the pulmonary venous pH was greater than 7.42. Alternating sodium bicarbonate and lactic acid infusion while alveolar Pco2 was maintained below 5 mmHg demonstrated the dependence of the hypocapnic response on the acid-base status of the blood perfusing the respiratory airways. The increase in resistance and decrease in compliance observed at a pulmonary venous pH of 7.64 was comparable to that observed after lobar pulmonary artery occlusion. Varying degrees of hypoxia did not significantly affect bronchomotor tone, nor was the bronchoconstriction following lobar pulmonary artery occlusion affected by the hypoxia. Vagal stimulation superimposed on a stepwise increase in pulmonary venous pH from 7.32 to 7.62 resulted in an increase in resistance which paralleled the increase in resistance when pulmonary venous pH alone was increased. Compliance was not significantly affected by vagal stimulation at any level of pulmonary venous pH.

Prolonged methacholine-induced bronchoconstriction in dogs

1979 ◽  
Vol 47 (2) ◽  
pp. 418-424 ◽  
Author(s):  
J. W. Ramsdell ◽  
P. F. Georghiou
Keyword(s):  
Lung Function ◽  
Gas Exchange ◽  
Lung Compliance ◽  
Cholinergic Stimulation ◽  
Partial Pressure Of Oxygen ◽  
Pulmonary Resistance ◽  
Mechanically Ventilated ◽  
Arterial Partial Pressure ◽  
Dynamic Lung Compliance ◽  
And Control

We studied the effect of prolonged airways obstruction induced by extended cholinergic stimulation in five anesthetized, mechanically ventilated dogs. A continuous intravenous metacholine infusion was utilized to maintain pulmonary resistance (RL) at 200--1500% preinfusion levels for 13--23 h. At maximum RL (18.86 +/- 7.74 vs. 2.09 +/- 0.18 (mean +/- SD) cmH2O/ (L/S) PREINfusion; P less than 0.01), dynamic lung compliance (Cdyn) fell from 67.5 +/- 14.6 to 32.7 +/- 11.6 ml/cmH2O (P less than 0.005) and arterial partial pressure of oxygen (PaO2) fell modestly from 95.8 +/- 6.1 Torr preinfusion to 83.2 +/- 12.7 Torr (P less than 0.05). Tachyphylaxis to methacholine developed, requiring increases in infusion rates to maintain elevated RL. Abnormalities in lung function resolved promptly upon termination of the infusion. Two similarly instrumented control animals ventilated for 19 and 25 h without metacholine infusion had no change in RL, Cdyn, or PaO2. Histological examination of the lungs revealed no differences between infused and control animals. In spite of marked increases in RL, prolonged cholinergic stimulation produced only mild changes in gas exchange and no sustained changes in lung function or structure.

LOSS OF PHOSPHOLIPID IN THE SKIN OF TUMOR-BEARING RATS

1959 ◽  
Vol 37 (1) ◽  
pp. 1447-1451
Author(s):  
Eldon M. Boyd ◽  
Irene E. Millar
Keyword(s):  
Significant Rise ◽  
Albino Rats ◽  
Cholesterol Esters ◽  
Tumor Bearing ◽  
Significant Fall

There occurs a unique, statistically significant fall in the level of phospholipid in the skin of albino rats bearing large Walker carcinosarcomata 256. The shift is similar to that produced by application of methylcholanthrene. It is preceded by loss of skin weight and increases in levels of skin water, cholesterol, and cholestrol esters. It is accompanied by loss of skin neutral fat and cholesterol esters. The quadratic shift in cholesterol esters occurs in hair before it occurs in skin, and is accompanied by a loss of hair weight and a slight but significant rise in levels of hair neutral fat. Declining levels of skin phospholipid may be part of the mechanism of production of the sallow appearance of the skin in late malignancy.

Lung compliance and pulmonary flow resistance

1963 ◽  
Vol 34 (2) ◽  
pp. 127-141 ◽  
Author(s):  
I.Leonard Bernstein ◽  
Alfred Kreindler
Keyword(s):  
Flow Resistance ◽  
Lung Compliance ◽  
Pulmonary Flow

Comparative aspects of the dynamics of breathing in newborn mammals

1983 ◽  
Vol 54 (5) ◽  
pp. 1229-1235 ◽  
Author(s):  
J. P. Mortola
Keyword(s):  
Body Size ◽  
Respiratory System ◽  
Dynamic Properties ◽  
Upper Airway ◽  
Lung Compliance ◽  
Expiratory Time ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Dynamic Lung Compliance ◽  
Spontaneously Breathing

Static and dynamic properties of the respiratory system have been studied in anesthetized, tracheostomized newborns of six species, ranging in size from rats to piglets. Respiratory system compliance (Crs), total resistance of respiratory system (Rrs), and expiratory time constant (tau) have been measured in the paralyzed passively ventilated animals. Crs is found to be proportional to body weight (BW0.80) and Rrs to BW-0.75; tau is independent of body size, the shortest value being in kittens and guinea pigs and a value of about 0.14 s in the other species. Including the upper airway resistance, tau becomes approximately 0.22 s. This value is similar to the expiratory time of the fastest breathing species; therefore in the smallest species the high breathing rate can be regarded as a mechanism to raise end-expiratory level. On a few occasions, dynamic lung compliance and pulmonary resistance, measured in spontaneously breathing kittens, puppies, and piglets were, respectively, smaller and larger than Crs and Rrs, suggesting that the hysteresis of the pressure-volume curve may be substantial. Rrs was almost linear within the volume and flow range investigated, with the Rohrer's constant K2 always being less than 2.5% of K1. The Reynolds number increases with body size (alpha BW0.51) more than is predictable from the changes in tracheal diameter, since the tracheal flow velocity is not an interspecific constant.

Location and mechanism of airway constriction after barium sulfate microembolism

1964 ◽  
Vol 19 (3) ◽  
pp. 387-394 ◽  
Author(s):  
J. A. Nadel ◽  
H. J. H. Colebatch ◽  
C. R. Olsen
Keyword(s):  
Histamine Release ◽  
Barium Sulfate ◽  
Transpulmonary Pressure ◽  
Smooth Muscle Contraction ◽  
Lung Compliance ◽  
Pulmonary Resistance ◽  
Airway Constriction ◽  
Large Airways ◽  
Residual Capacity ◽  
The Right

Injection of barium sulfate microemboli into the right side of the heart of paralyzed, artificially ventilated cats increased pulmonary resistance, decreased pulmonary compliance and functional residual capacity, and increased end-expiratory transpulmonary pressure and anatomic dead space. These effects could be due to constriction of terminal respiratory units without significant narrowing of the large airways, which may actually enlarge. Anatomic studies, performed after rapid freezing of the lungs in the open thorax, showed that the principal site of constriction was the alveolar ducts. Intravenous isoproterenol partially or completely prevented the changes following microembolism, suggesting that they were due to smooth muscle contraction. Vagotomy, injection of heparin or atropine or guanethedine, or inhalation of 6% carbon dioxide did not prevent the changes; prior injections of 48/80 decreased the changes. These studies suggest that the embolism-induced changes depend on histamine release. The varied manifestations of barium sulfate microembolism, including the shift of ventilation to the unaffected areas, atelectasis of embolized areas, anoxemia, and abnormal breathing pattern may depend on the presence and extent of contraction of peripheral respiratory units induced by liberation of histamine. terminal airway constriction; histamine release; lung compliance; pulmonary resistance; airway anatomy; alveolar duct; muscle Submitted on August 30, 1963

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