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PubMed1987

Comparison of various approaches used to assess the functional state of the cardiac and respiratory system in patients undergoing rehabilitation following cardiac surgery.

A total of 338 patients aged 10 to 56 years, who had undergone various cardiac operations, were divided, on the basis of a spiroergometric examination, performed together with the determination of maximal oxygen intake (MOI), into 4 functional classes. Determination of functional aerobic impairment, i.e. the magnitude of deviation of the established MOI value from that theoretically anticipated in view of the patient's age and sex, made it possible to determine the degree of decrease in the reserve capacity of the patient's cardiac and respiratory system (CRS). Comprehensive assessment of the functional state of the CRS, while taking into account the patient's individual characteristics, is a prerequisite for a differentiated quantitative approach to the design of rehabilitation programmes.

Adolescent↗
PubMed1988

Elastic properties of the rat respiratory system related to age.

The experiments were performed on male rats of the Wistar strain under urethane anaesthesia (1.3 g/kg i.p.). Changes of oesophageal and tracheal pressures were registered in a group of 30 spontaneously breathing, supine rats, of 295 +/- 13 g average body weight during lung inflations with 1-5 ml of air. In another group of 25 rats of 70 +/- 6 g average body weight (young rats) we made the measurements during inflation with volumes 0.5-2 ml. The measurements were also performed in a group of 10 paralyzed, ventilated rats with 347 +/- 24 g average body weight and inflations 1-5 ml. Compliance of the lungs (CL), chest wall (CW) and of the respiratory system (Crs) was calculated from the linear part of the pressure-volume curve during inflation. The results indicate: 1. Cw is significantly (p less than 0.001) higher in young (134.7 ml.kPa-1.kg-1) than in adult rats (44.1 ml.kPa-1.kg-1). CL (related to body weight) is not significantly different in young and adult rats. 2. Cw is significantly (p less than 0.001) higher than CL. 3. No difference was observed in CLs Cw and Crs between paralyzed and spontaneously breathing animals.

Aging↗
PubMed1999

Control and interaction of the cardiovascular and respiratory systems in anuran amphibians.

In anuran amphibians, respiratory rhythm is generated within the central nervous system (CNS) and is modulated by chemo- and mechanoreceptors located in the vascular system and within the CNS. The site for central respiratory rhythmogenesis and the role of various neurotransmitters and neuromodulators is described. Ventilatory air flow is generated by a positive pressure, buccal force pump driven by efferent motor output from cranial nerves. The vagus (cranial nerve X) also controls heart rate and pulmocutaneous arterial resistance that, in turn, affect cardiac shunts within the undivided anuran ventricle; however, little is known about the control of central vagal motor outflow to the heart and pulmocutaneous artery. Anatomical evidence indicates a close proximity of the centers responsible for respiratory rhythmogenesis and the vagal motoneurons involved in cardiovascular regulation. Furthermore, anurans in which phasic feedback from chemo- and mechanoreceptors is prevented by artificial ventilation exhibit cardiorespiratory interactions that appear similar to those of conscious animals. These observations indicate interactions between respiratory and cardiovascular centers within the CNS. Thus, like mammals and other air-breathing vertebrates, the cardio-respiratory interactions in anurans result from both feedback and feed-forward mechanisms.

Animals↗
PubMed1990

Spectral characteristics of sound transmission in the human respiratory system.

The amplitude of sound transmission from the mouth to a site overlying the extrathoracic trachea and two sites on the right posterior chest wall over the 100-600 Hz frequency range was measured in eight healthy adult subjects. An acoustic driver and a rigid tube were employed to introduce sound into the mouths of the subjects at resting lung volume, and the transmission measurements were performed using lightweight accelerometers. Similar spectral characteristics of acceleration were observed in all of the subjects showing peaks in the transmission. These characteristics included 1) two regions of increased transmission over the frequency range of the measurements, 2) a decrease in the magnitude of acceleration of the chest wall as compared to the tracheal site of roughly 20 dB at lower frequencies, 3) a strong trend of decreasing acceleration of the chest wall with increasing frequency. These spectra agreed favorably with the predictions of a theoretical model of the acoustical properties of the respiratory system. The model suggests the primary structural determinants of a number of the observed characteristics including the importance of the lung parenchyma in sound attenuation.

Adult↗
PubMed1978

Training and oxygen conductance in the elderly. I. The respiratory system.

Static lung volumes, closing volumes and pulmonary diffusing capacity have been measured in a group of 19 subjects (9 M, 10 F) 60 - 76 years old, all volunteers for an exercise training program (nominal 4 hours per week for 11 weeks). Initial static lung volumes were larger than in some previous series, perhaps because our sample was health-conscious and mainly nonsmokers. Training produced no significant changes in any of the pulmonary variables tested, despite a 10% increase of maximum oxygen intake seen in those members of the group who progressed to intensive training (heart rate 145 - 155/min). This reflects the fact that oxygen transport depends more on blood transport than on the respiratory system.

Age Factors↗
PubMed1995

[Influence of stellate ganglion block on respiratory system].

The purpose of this study was to investigate the influence of a stellate ganglion block (SGB) or stellate ganglion electrical stimulation (SGES) on pulmonary resistance, on blood flows of the bronchial, pulmonary and common carotid arteries, and on arterial blood gases. Thirteen mongrel dogs were divided into two groups; a SGB group (n = 8) and a SGES group (n = 5). Anesthesia was induced with pentobarbital 25 mg.kg-1 and the animals were mechanically ventilated to maintain constant PaO2 (90-100 mmHg) and PaCO2 (35-40 mmHg). After a thoracotomy, the SGB with 0.5% mepivacaine 1.5 ml was performed, or the SGES was performed at a strength of 12 volts, and at a frequency of 50 Hz, applied for 30 min. In the SGB group, pulmonary resistance after the block did not significantly differ from the control. No significant change occurred in blood flows of the bronchial and pulmonary arteries, but the common carotid artery flow increased significantly after the SGB. Arterial blood gases did not change significantly after the SGB. In the SGES group, pulmonary resistance after the stimulation did not significantly differ from the pre-value. However, blood flows of the bronchial, pulmonary and common carotid arteries decreased significantly after the SGES. Arterial blood gases did not change significantly after the SGES. These results suggest that the SGB may not influence the respiratory system under normal conditions.

Animals↗
PubMed1998

Assessment of respiratory system viscoelasticity in spontaneously breathing rabbits.

Airflow, volume (V), inspiratory time (TI), tracheal pressure (Ptr), abdomen (Dab) and rib cage diameters (Drc), peak diaphragm (Adi) and parasternal muscle activity (Aic) were measured in thirteen anaesthetized and vagotomized rabbits and in six vagotomized rabbits with cordotomy at T1 during unimpeded inspirations followed by rapid end-inspiratory airway occlusion, relaxation against closed airways, and inspiratory effort. To modify the inspiratory flow pattern, such sequences were performed at different volume, levels of chemical drive, and body temperatures (BT). Under all conditions, Adi, Aic, TI, Drc and Dab at iso-volume were the same for unimpeded and occluded inspirations; end-inspiratory Ptr was lower for occluded than for unimpeded inspirations, the difference (Pdiff) being larger the lower the volume at which occlusions were performed and the higher the chemical drive and BT. After paralysis, the viscoelastic constants of the respiratory system, modelled as a Kelvin body, were assessed according to the rapid airway occlusion method and used together with the inspiratory flow waveform to predict the end-inspiratory viscoelastic pressure (Pvisc) of unimpeded inspirations. Since the slope of the Pdiff vs. Pvisc relationship never differed from unity, Pdiff under the specified conditions should represent the effective Pvisc of unimpeded inspirations.

Animals↗
PubMedDate not supplied

Ventilatory response to CO2. I. A psychobiologic marker of the respiratory system.

When a gas mixture containing CO2 is breathed by a healthy subject, alveolar ventilation is increased. The ratio delta ventilation/delta PCO2 has been termed the ventilatory response to CO2 (S). Since the development of a rebreathing method in 1967, it has proved easy to measure this index of the regulation of ventilation. This index, although showing considerable interindividual variation (range, 0.5-9 liters/min/mm PCO2), tends to be consistent over time for any given individual. Positive correlations between S and personality traits such as anxiety, extroversion, and aggression and negative correlations between S and certain scales of the Minnesota Multiphasic Personality Inventory (MMPI: depression, psychopathology, psychasthenia, and social introversion) have been found in previous studies. It was hypothesized that S may be a psychobiologic marker of the respiratory system. A project in which 82 normal subjects (50 male, 32 female) were studied with both psychologic (Eysenck Personality Inventory, Catell 16PF, and 168-item MMPI) and rebreathing tests was undertaken to investigate this possibility further. A strong correlation between S and neurotic personality traits was found, but this correlation appeared valid only in female subjects.

Adult↗
PubMed1979

[Effect of metal dust on the respiratory system. II. Clinical examinations].

Studies were carried out in 4 groups of workers occupationally exposed to cadmium, tungsten, manganese and lead. All those groups were homogeneous, composed exclusively of men aged 35--45, of similar height, body weight, and duration of employment above 10 years. Following the same criteria, a group of forestry workers, unexposed to dust, was randomly selected. The smoking habit was similar in all groups. Several--days--clinical observation included a detailed interview (MRC questionnaire), physical and radiological examination and a wide range of functional tests of lungs. The results reveal clinical and physiopathological symptoms which might be indicative of emphysema. The results of some studies also indicate the possibility of intraparenchymatous fibrosis of lungs in the tungsten--exposed--workers. No clear effects upon the respiratory system were found.

Adult↗
PubMed1990

Quasi-static pressure-volume hysteresis in the canine respiratory system in vivo.

We investigated the quasi-static pressure-volume (P-V) hysteresis of the normal canine lung in vivo by performing 15-s flow interruptions at various points throughout the breathing cycle in mechanically ventilated anesthetized paralyzed dogs. By measuring the transpulmonary pressure (Ptp) at 5 s after each interruption, we built up a quasi-static P-V loop of the lungs. We found, however, that the area of the loop was significantly smaller (by a factor of 4-6) than has been reported by others for the isolated canine lung. We also found the hysteresis loop area of the chest wall to be of similar magnitude. If we measured Ptp 10-15 s after interruption, we found it always decreased at a rate expected to result from continuing gas exchange in the lungs. We conclude that 1) the areas of the quasi-static P-V loop in vivo for the total respiratory system, as well as the lungs and chest wall separately, are significantly smaller than has been reported previously for isolated lungs and 2) continuing gas exchange in the lungs places a lower limit on the frequencies (equivalent to flow interruptions of greater than 5- to 7-s duration) at which the P-flow-V behavior of the lungs in vivo can be considered in purely mechanical terms.

Animals↗
PubMed2004

Peak volume history and peak pressure-volume curve pressures independently affect the shape of the pressure-volume curve of the respiratory system.

OBJECTIVE: To determine the specific effect of peak volume history pressure on the inflation limb of the pressure-volume curve and peak pressure-volume curve pressure on the deflation limb of the pressure-volume curve. DESIGN: Prospective assessment of pressure-volume curves in saline, lung lavage injured sheep. SETTING: Large animal laboratory of a university-affiliated hospital. SUBJECTS: Eight female Dorset sheep. INTERVENTIONS: : The effect of two volume history pressures (40 and 60 cm H2O) and three pressure-volume curve peak pressures (40, 50, and 60 cm H2O) were randomly compared. MEASUREMENTS AND MAIN RESULTS: Peak volume history pressure affected the inflation curve beyond the lower inflection point but did not affect the inflection point (Pflex). Peak pressure-volume curve pressure affected the deflation curve. Increased peak volume history pressure increased inflation compliance (p <.05). Increased peak pressure-volume curve pressure increased the point of maximum compliance change on the deflation limb and deflation compliance and decreased compliance between peak pressure and the point of maximum curvature on the deflation limb (p <.05). CONCLUSION: Peak volume history pressure must be considered when interpreting the inflation limb of the pressure-volume curve of the respiratory system beyond the inflection point. The peak pressure achieved during the pressure-volume curve is important during interpretation of deflation compliance and the point of maximum compliance change on the deflation limb.

Animals↗
PubMed1981

Design of the mammalian respiratory system. III Scaling maximum aerobic capacity to body mass: wild and domestic mammals.

The purpose of this study was to determine whether the maximal rate of oxygen consumption (Vo2max) is scaled proportionally to Mb1.0, as the diffusing capacity of the lung, or proportionally to Mb0.75, as the standardized resting rate of oxygen consumption (V02std). We measured Vo2max on a variety of mammalian species (14 wild species and 8 domestic or laboratory species ranging in Mb from 7.2 g to 263 kg) using the same 'treadmill' procedure for all animals. For the wild species we found: Vo2max = 1.94.Mb0.79; r=0.995 where Vo2max has the units ml . sec-1 and mb is in kg. There was a great variability in Vo2max among domestic species of the same size, horse and dog having a Vo2max more than 3 times that of a cow and sheep, respectively. Both the variability in Vo2max with body size and among animals of the same size provide powerful tools for investigating the relationship between structure and function at each step in the respiratory system, from the oxygen in environmental air to the oxygen sink in the mitochondria.

Aerobiosis↗
PubMed1981

Quantitative analysis of the respiratory system of the house sparrow, budgerigar and violet-eared hummingbird.

In the house sparrow, the budgerigar and the violet-eared hummingbird the volumes of the lungs and air sacs are estimated from silicone casts. The quantitative composition of the lungs and of their compartments are measured on lung slices, the relative volumes of the parabronchi on histological sections, and the volume composition of the blood-air capillary network of the parabronchi on electron micrographs. On electron micrographs the exchange surface and the thickness of the air-blood diffusion barrier are also measured. From these data the morphological membrane diffusion capacity is calculated and related to several organ weights. The volume of the lungs and air sacs makes up 14-22% of the total body volume, the lungs only 2.3-2.9%. The exchange surface varies from 61 cm2/g (budgerigar) over 70 cm2/g (house sparrow) to 99 cm2/g (violet-eared hummingbird). The very thin barrier in these small birds results in a membrane diffusion capacity of 0.122 in budgerigars up to 0.271 ml O2/mm Hg . min . g in violet-eared hummingbirds. The various parameters are compared with those of corresponding mammals, and the quantitative advantages of the avian respiratory system are discussed.

Animals↗
PubMed2001

Development of a standardized nomenclature for bronchoscopy of the respiratory system of harbor porpoises (Phocoena phocoena).

Respiratory disease is common in captive and wild cetaceans. Bronchoscopy may permit early diagnosis of respiratory disease in dolphins and porpoises. Refinement of cetacean bronchoscopy requires development of a nomenclature system to facilitate description of the anatomic site at which lesions occur. A standard bronchoscopic nomenclature also permits serial evaluations of lesions and enhances communication between veterinarians. In this project, we adapted the bronchoscopic nomenclature devised by Amis and McKiernan for the dog and horse to the harbor porpoise (Phocoena phocoena). Silastic and air-dried models of the bronchial tree of the harbor porpoise were made to illustrate the anatomy and devise the nomenclature. Bronchial anatomy was consistent among the four porpoise lungs studied. The Amis and McKiernan nomenclature was readily adaptable to the harbor porpoise lung with minor modifications and may be useful for cetacean bronchoscopy.

Animals↗
PubMed1994

Protein 1 and Clara cell 10-kDa protein distribution in normal and neoplastic tissues with emphasis on the respiratory system.

Thirty-six different normal tissues and 13 different malignant epithelial tumours, were examined immunohistochemically for the presence of protein 1 (P1) and Clara cell 10-kDa protein (CC10). Adenocarcinomas of the lung were also examined for the expression of pulmonary surfactant apoprotein using a monoclonal antibody (PE-10). The staining results of P1 and CC10 were almost identical both in normal tissues and in malignant tumours. In normal lung, Clara cells were strongly positive for both P1 and CC10. In addition, some goblet cells and non-ciliated non-mucus cells in the upper airways were moderately positive for both proteins. In the malignant tumours, some lung cancers were positive for P1 and CC10, both of which were positive in the same tumour cells on sequential sections. In 117 lung cancers, P1 and CC10 were positive in 10.2% of adenocarcinomas, 20.5% of squamous cell carcinomas, and 12.5% of large cell carcinomas. PE-10 stained positively in 65.3% of adenocarcinomas, a frequency significantly higher than that of P1 and CC10 (P < 0.01). These results suggest that P1 and CC10 are nearly identical proteins, that both are useful markers of Clara cells, and that many pulmonary adenocarcinomas express surfactant apoprotein rather than Clara cell proteins.

Adenocarcinoma↗