Ovalbumin-induced lung disease in the pony: role of vagal mechanisms

1982 ◽  
Vol 53 (3) ◽  
pp. 719-725 ◽  
Author(s):  
F. J. Derksen ◽  
N. E. Robinson ◽  
R. F. Slocombe
Keyword(s):  
Respiratory System ◽  
Minute Ventilation ◽  
Left Lung ◽  
Arterial Oxygen Tension ◽  
Lung Compliance ◽  
Arterial Oxygen ◽  
Pulmonary Mechanics ◽  
Vagal Blockade ◽  
Before And After ◽  
Respiratory System Resistance

In awake sensitized ponies, we studied the effect of aerosol ovalbumin challenge on ventilation, pulmonary mechanics, lung volume, and gas exchange before and after vagal blockade. We also challenged the left lung and measured respiratory rate (f) and right and left respiratory system resistance (RrsR, RrsL) before and after both left and bilateral vagal section. Bilateral ovalbumin aerosol challenge increased f, minute ventilation (VE), total respiratory system resistance (Rrs), and minimal volume, decreased dynamic compliance, total lung capacity, and arterial oxygen tension, and was without effect on tidal volume (VT), functional residual capacity, quasi-static lung compliance, and arterial carbon dioxide tension. Vagal blockade reversed the increase in f, VE, and Rrs and increased VT. Challenge of the left lung increased f and RrsL but did not alter RrsR. Bilateral vagal section reversed the tachypnea but unilateral section did not. Histopathologic lesions included acute fibrinopurulent obstructive bronchiolitis, bronchitis, edema, and alveolar distension. We conclude that local mechanisms are of critical importance in the pathogenesis of ovalbumin-induced airway obstruction in ponies, that increased sensitivity of airway smooth muscle to normal vagal tone may also play a role, and that tachypnea following challenge is caused by activity of pulmonary receptors with vagal afferent fibers.

Pulmonary Function in Chronic Severe Anaemia

1971 ◽  
Vol 40 (4) ◽  
pp. 317-325 ◽  
Author(s):  
J. S. Guleria ◽  
J. N. Pande ◽  
M. M. Markose ◽  
R. G. Gupta ◽  
B. P. Jain
Keyword(s):  
Oxygen Tension ◽  
Minute Ventilation ◽  
Pulmonary Ventilation ◽  
Young Patients ◽  
Arterial Oxygen Tension ◽  
Carbon Dioxide Production ◽  
Severe Anaemia ◽  
Arterial Oxygen ◽  
Pulmonary Mechanics ◽  
Diffusing Capacity

1. The process of pulmonary ventilation and gas exchange was investigated in twenty-three young patients with chronic severe anaemia, before and after its correction. 2. Various lung volumes, pulmonary mechanics, minute ventilation, oxygen consumption and carbon dioxide production were found to be normal in anaemic patients. 3. There was a mild respiratory alkalosis in anaemia. The arterial oxygen tension was lowered because of a marked widening of the alveolar-arterial oxygen tension gradient. This was mainly because of an increase in the anatomical shunt as well as ventilation/perfusion inequalities. 4. The transfer factor (pulmonary diffusing capacity) in anaemia was very much reduced. The diffusing capacity of the alveolar capillary membrane was usually decreased and volume of blood in the alveolar capillaries usually increased but these changes were not statistically significant.

PERIODIC BREATHING AND APNEA IN PRETERM INFANTS. II. HYPOXIA AS A PRIMARY EVENT

PEDIATRICS ◽  
1972 ◽  
Vol 50 (2) ◽  
pp. 219-228
Author(s):  
Henrique Rigatto ◽  
June P. Brady
Keyword(s):  
Preterm Infants ◽  
Oxygen Tension ◽  
Minute Ventilation ◽  
Arterial Oxygen Tension ◽  
Blood Gases ◽  
Periodic Breathing ◽  
Capillary Blood ◽  
Arterial Oxygen ◽  
Primary Event ◽  
The Relationship

We studied nine healthy preterm infants during the first 35 days of life to define the relationship between periodic breathing, apnea, and hypoxia. For this purpose we compared ventilation/apnea (V/A), minute ventilation, and alveolar and capillary blood gases during periodic breathing induced by hypoxia and during spontancous periodic breathing in room air. We induced periodic breathing by giving the baby in sequence 21, 19, 17, and 15% O2 to breathe for 5 minutes each, and also by giving 21, 15, and 21% O2. We measured ventilation with a nosepiece and a screen flowmeter. With a decrease in arterial oxygen tension, preterm infants (1) hypoventilated, (2) breathed periodically more frequently, and (3) showed a decrease in V/A due to an increase in the apneic interval. In one baby this led to apnea lasting 30 seconds. These findings support our hypothesis that preterm infants breathing periodically hypoventilate and suggest that hypoxia may be a primary event leading to periodic breathing and apnea.

Mechanics of the respiratory system in the newborn tammar wallaby

2002 ◽  
Vol 205 (4) ◽  
pp. 533-538 ◽  
Author(s):  
P. M. MacFarlane ◽  
P. B. Frappell ◽  
J. P. Mortola
Keyword(s):  
Respiratory System ◽  
Spontaneous Breathing ◽  
Minute Ventilation ◽  
Pulmonary Ventilation ◽  
Age Groups ◽  
Mechanical Efficiency ◽  
Tammar Wallaby ◽  
Ventilatory Equivalent ◽  
Rate Of Oxygen Consumption ◽  
Respiratory System Resistance

SUMMARY We investigated whether the mechanical properties of the respiratory system represent a major constraint to spontaneous breathing in the newborn tammar wallaby Macropus eugenii, which is born after a very short gestation (approximately 28 days, birth mass approximately 380 mg). The rate of oxygen consumption (V̇O2) through the skin was approximately 33 % of the total V̇O2 at day 1 and approximately 14 % at day 6. The mass-specific resting minute ventilation (V̇e) and the ventilatory equivalent (V̇e/V̇O2) were approximately the same at the two ages, with a breathing pattern significantly deeper and slower at day 1. The mass-specific compliance of the respiratory system (Crs) did not differ significantly between the two age groups and was close to the values predicted from measurements in eutherian newborns. Mass-specific respiratory system resistance (Rrs) at day 1 was higher than at day 6, and also higher than in eutherian newborns. Chest distortion, quantified as the degree of abdominal motion during spontaneous breathing compared with that required to inflate the lungs passively, at day 1 was very large, whereas it was modest at day 6. We conclude that, in the tammar wallaby at birth, the high resistance of the respiratory system and the distortion of the chest wall greatly reduce the mechanical efficiency of breathing. At this age, gas exchange through the skin is therefore an important complement to pulmonary ventilation.

Ontogeny of dry gas hyperpnea-induced bronchoconstriction in guinea pigs

1994 ◽  
Vol 76 (3) ◽  
pp. 1150-1155 ◽  
Author(s):  
T. M. Murphy ◽  
D. W. Ray ◽  
L. E. Alger ◽  
I. J. Phillips ◽  
J. C. Roach ◽  
...  
Keyword(s):  
Respiratory System ◽  
Guinea Pigs ◽  
Minute Ventilation ◽  
Similar Degree ◽  
Fractional Increase ◽  
Respiratory System Resistance ◽  
Key Features

Adolescent guinea pigs (AGPs) demonstrate dry gas hyperpnea-induced bronchoconstriction (HIB) that shares key features with HIB in humans with asthma. The airways of immature animals exhibit enhanced reactivity to diverse types of stimulation. We tested whether dry gas HIB is also increased in newborn guinea pigs (NGPs). We quantified HIB as the fractional increase of respiratory system resistance (Rrs) over baseline (BL) in five 4- to 7-day-old NGPs after 10 min of hyperpnea, as well as changes in Rrs elicited by intravenous methacholine or capsaicin, and compared these responses with those of AGPs. During hyperpnea, analogous stimuli were delivered by mechanically imposing hyperpnea at 3.0, 4.5, and 6.0 times quiet eucapnic minute ventilation (VE). In AGPs, hyperpnea caused significant bronchoconstriction that increased with VE; peak fractional increase of Rrs was 7.6 +/- 2.0 times BL. In contrast, hyperpnea caused insignificant bronchoconstriction in NGPs (1.4 +/- 0.2 times BL after the largest VE; P < 0.05 vs. AGP). Responses elicited by methacholine (10(-10)-10(-7) mol/kg) or capsaicin (0.01–10.0 microgram/kg) were similar in NGPs and AGPs. In AGPs, hyperpnea suppressed HIB until posthyperpnea. To determine whether the reduced HIB of NGPs was caused by enhanced suppression, NGPs and AGPs were administered acetylcholine (10(-10)-10(-7) mol/kg i.v.) during BL eucapnic ventilation and during eucapnic hyperpnea with warm humidified gas. Responses to acetylcholine were suppressed in AGPs and NGPs to a similar degree. We conclude that HIB is markedly diminished shortly after birth in guinea pigs and that it increases substantially during maturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Ontogeny of respiratory control and pulmonary mechanics in newborn rabbits

1985 ◽  
Vol 59 (5) ◽  
pp. 1477-1486 ◽  
Author(s):  
M. M. Grunstein ◽  
D. T. Tanaka
Keyword(s):  
Mechanical Properties ◽  
Tidal Volume ◽  
Respiratory System ◽  
Minute Ventilation ◽  
Work Of Breathing ◽  
Relative Volume ◽  
Respiratory Pattern ◽  
Pulmonary Mechanics ◽  
Volume Loss ◽  
Age Related

Maturation of the respiratory pattern and the active and passive mechanical properties of the respiratory system were assessed in 19 tracheotomized rabbits (postnatal age range: 1–26 days) placed in a body plethysmograph. With maturation both minute ventilation and tidal volume significantly increased, whereas respiratory frequency decreased. When normalized for body weight (kg) both the passive (Rrs X kg) and active (R'rs X kg) resistances of the respiratory system significantly increased with age, whereas the corresponding passive (Crs X kg-1) and active (C'rs X kg-1) compliances significantly decreased. At any given age R'rs X kg only slightly exceeded Rrs X kg, whereas C'rs X kg-1 was significantly lower than Crs X kg-1. Moreover, the maturational increases in Rrs X kg and R'rs X kg exceeded the corresponding decreases in Crs X kg-1 and C'rs X kg-1, resulting in significant age-related increases in both the passive (tau rs) and active (tau'rs) time constants of the respiratory system. Due to the age-related increases in tau'rs, producing a delayed volume response to any given inspiratory driving pressure, the relative volume loss obtained at any time during inspiration was greater in the maturing rabbit. On the other hand, because of concomitant compensatory changes in respiratory pattern, evidenced by increases in inspiratory duration with age, the end-inspiratory tidal volume loss in the maturing animal was maintained generally less than 10% at all postnatal ages. Thus maturational changes in respiratory pattern appear coupled to changes in the active mechanical properties of the respiratory system. The latter coupling serves to optimize the transduction of inspiratory pressure into volume change in a manner consistent with establishing the minimum inspiratory work of breathing during postnatal development.

Role of Vagal Airway Reflexes in Control of Ventilation in Pulmonary Fibrosis

1981 ◽  
Vol 61 (6) ◽  
pp. 781-784 ◽  
Author(s):  
J. Savoy ◽  
S. Dhingra ◽  
N. R. Anthonisen
Keyword(s):  
Pulmonary Fibrosis ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Arterial Oxygen ◽  
Control Subjects ◽  
Cough Response ◽  
Before And After ◽  
The Mean ◽  
Breath Cycle

1. in 10 patients with pulmonary fibrosis and in seven control subjects, we measured the pressure at the mouth 0.1 s after onset of an inspiration against occluded airway (P0.1), minute ventilation (VI), breathing frequency (fr), tidal volume (VT), inspiratory duration (Tl) and calculated the mean inspiratory flow (VT/Tl) and the fraction of the breath cycle devoted to inspiration (Tl/Ttot.). in the patients measurements were made at normal arterial oxygen saturations (Sao2), before and after lignocaine airway anaesthesia. 2. Efficacy of airway anaesthesia was tested by the cough response to citric acid inhalation. 3. in pulmonary fibrosis P0.1, f1 and VT/Tl were greater than in the control subjects, VT and Tl, were smaller and Tl/Ttot. and VI were not different. 4. Effective airway anaesthesia did not modify P0.1 and breathing pattern parameters observed in pulmonary fibrosis. 5. These results suggest that airway receptors do not contribute to a major extent to the control of breathing in pulmonary fibrosis.

Cardiopulmonary adaptations to pneumonectomy in dogs. III. Ventilatory power requirements and muscle structure

1994 ◽  
Vol 76 (5) ◽  
pp. 2191-2198 ◽  
Author(s):  
C. C. Hsia ◽  
L. F. Herazo ◽  
M. Ramanathan ◽  
H. Claassen ◽  
F. Fryder-Doffey ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Respiratory System ◽  
Total Mass ◽  
Mechanical Characteristics ◽  
Minute Ventilation ◽  
Left Lung ◽  
Elastic Recoil ◽  
Inspiratory Muscles ◽  
Right Thoracotomy ◽  
The Right

Static and dynamic mechanical characteristics of the respiratory system were measured in five adult foxhounds 6–15 mo after right pneumonectomy (R-PNX) and in five matched foxhounds that underwent right thoracotomy without pneumonectomy (Sham). In R-PNX dogs, elastic recoil was lower than that in the left lung of Sham dogs. On exercise, absolute ventilatory power requirements of the lung and its components were measured, i.e., power requirements to overcome elastic and viscous resistances of the lung as well as power requirements during inspiration and expiration. All components were higher for a given minute ventilation in R-PNX dogs than in both lungs of Sham dogs. Ventilatory power requirements after R-PNX were also higher than in three adult foxhounds after left PNX studied previously by the same techniques. After R-PNX, the mass of the right costal diaphragm and total mass of inspiratory muscles were greater than in Sham dogs. There were no significant differences in ultrastructural features of the costal diaphragm. The unilateral increase in muscle mass is likely the result of chronic elevation and stretch of the right costal diaphragm after R-PNX.

Pulmonary mechanics during the ventilatory response to hypoxemia in the newborn monkey

1983 ◽  
Vol 55 (3) ◽  
pp. 1008-1014 ◽  
Author(s):  
W. A. LaFramboise ◽  
R. D. Guthrie ◽  
T. A. Standaert ◽  
D. E. Woodrum
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Lung Compliance ◽  
Pulmonary Mechanics ◽  
Base Line ◽  
Respiratory Drive ◽  
Pulmonary Resistance ◽  
Residual Capacity ◽  
Dynamic Lung Compliance ◽  
Sustained Increase

Dynamic lung compliance (CL), inspiratory pulmonary resistance (RL), and functional residual capacity (FRC) were measured in 10 unanesthetized 48 h-old newborn monkeys and seven 21-day-old infant monkeys during acute exposures to an equivalent level of hypoxemia. End-expiratory airway occlusions were performed and the pressure developed by 200 ms (P0.2) was utilized as an index of central respiratory drive. P0.2 demonstrated a sustained increase throughout the period of hypoxemia on day 2 despite the fact that minute ventilation (VI) initially increased but then fell back to base-line levels. Dynamic lung compliance fell and FRC increased by 5 min of hypoxemia in the newborns. The 21-day-old monkeys exhibited a sustained increase in both VI and P0.2 throughout the hypoxic period with no change in CL and FRC. RL did not change at either postnatal age during hypoxemia. These data indicate that the neonatal monkey is subject to changes in pulmonary mechanics (decreased CL and increased FRC) during hypoxemia and that these changes are eliminated with maturation.

A comparison between medetomidine-ketamine and medetomidine-propofol anaesthesia in rabbits

1997 ◽  
Vol 31 (1) ◽  
pp. 58-69 ◽  
Author(s):  
Ludo J. Hellebrekers ◽  
Evert-Jan W. de Boer ◽  
Michiel A. van Zuylen ◽  
Hans Vosmeer
Keyword(s):  
Muscle Tone ◽  
Arterial Oxygen Tension ◽  
Arterial Oxygen ◽  
Physiological Variables ◽  
Arterial Blood ◽  
Jaw Muscle ◽  
Before And After ◽  
Anaesthetic Depth ◽  
Low Incidence ◽  
High Degree

We investigated the effects of combinations of the α2-agonist medetomidine with either ketamine or propofol for their overall quality of anaesthesia, including the possible concomitant changes in respiratory and circulatory function in New Zealand White rabbits. Medetomidine was administered at 0.35 mg/kg, intramuscularly. Following sedation, ketamine (5 mg/kg) or propofol (2 and 3 mg/kg) were administered intravenously via the ear vein. Data on reflexes (palpebral, corneal, ear-pinch and toe-pinch), jaw muscle tone and physiologic parameters (heart rate, blood pressure, respiration rate, body temperature) were recorded before and after administration of drugs. Intermittent arterial blood sampling was performed at predetermined intervals before and after anaesthesia. The results show that the ear-pinch and toe-pinch reflexes and the jaw muscle tone are reliable indices to determine surgical anaesthetic depth. A surgical level of anaesthesia could be obtained reliably with the combination medetomidine-ketamine and medetomidine-propofol (3 mg/kg) with a duration of 19 min (variation 10 to 40 min, n=6) and 11 min (variation 5 to 15 min, n=6), respectively. Propofol administered at 2 mg/kg did not produce an adequate anaesthetic level. The data from this study demonstrate a high degree of predictability in achieving a fast induction and adequate anaesthetic depth together with a low incidence of untoward side-effects and a zero mortality with the combinations investigated. The data from the medetomidine-ketamine group show that, although adequate anaesthetic depth of medium duration is achieved, the arterial oxygen tension is reduced to hypoxemic levels. With the use of this combination, the supplemental administration of oxygen is advised. With the combination of medetomidine-propofol (3 mg/kg) a short duration anaesthesia of adequate depth was achieved, whereby physiological variables all remained within acceptable ranges. The use of medetomidine-propofol, in combination with the α2-antagonist atipamezole to shorten recovery time, will provide reliable and very versatile anaesthesia in rabbits.

scholarly journals Gas exchange and ventilation–perfusion relationships in the lung

2014 ◽  
Vol 44 (4) ◽  
pp. 1023-1041 ◽  
Author(s):  
Johan Petersson ◽  
Robb W. Glenny
Keyword(s):  
Carbon Dioxide ◽  
Blood Flow ◽  
Gas Exchange ◽  
Minute Ventilation ◽  
Work Of Breathing ◽  
Arterial Oxygen Tension ◽  
Supplemental Oxygen ◽  
Arterial Oxygen ◽  
Respiratory Drive ◽  
Clinical Scenarios

This review provides an overview of the relationship between ventilation/perfusion ratios and gas exchange in the lung, emphasising basic concepts and relating them to clinical scenarios. For each gas exchanging unit, the alveolar and effluent blood partial pressures of oxygen and carbon dioxide (PO2andPCO2) are determined by the ratio of alveolar ventilation to blood flow (V′A/Q′) for each unit. Shunt and lowV′A/Q′ regions are two examples ofV′A/Q′ mismatch and are the most frequent causes of hypoxaemia. Diffusion limitation, hypoventilation and low inspiredPO2cause hypoxaemia, even in the absence ofV′A/Q′ mismatch. In contrast to other causes, hypoxaemia due to shunt responds poorly to supplemental oxygen. Gas exchanging units with little or no blood flow (highV′A/Q′ regions) result in alveolar dead space and increased wasted ventilation,i.e.less efficient carbon dioxide removal. Because of the respiratory drive to maintain a normal arterialPCO2, the most frequent result of wasted ventilation is increased minute ventilation and work of breathing, not hypercapnia. Calculations of alveolar–arterial oxygen tension difference, venous admixture and wasted ventilation provide quantitative estimates of the effect ofV′A/Q′ mismatch on gas exchange. The types ofV′A/Q′ mismatch causing impaired gas exchange vary characteristically with different lung diseases.

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