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PubMedDate not supplied

[The biological age of the respiratory system].

A model of the biological age of the respiratory system is described. The following biological age determinants are used: vital lung capacity, maximal breathing capacity, mid-expiratory flow rate, oxygen consumption. They commonly meet the requirements of the biological age measurement tests as well as reflect main symptoms of the respiratory system ageing. The proposed model has been used to study the peculiarities of the respiratory system ageing in the Abkhasian population and to assess the effect of smoking on this process.

Adult↗

PubMed1982

[Non-ventilatory functions of the cells of the respiratory system].

The physiology of the respiratory system was limited until recently to study of the structures subjected to simple physical laws and involved in gas exchanges only. Today, the airways and lung itself are conceived as complex living structures adapted to defence against exogenous, microbiological, organic and inorganic substances which reach the respiratory epithelium, contained in the 10 to 12 m3 of air entering and leaving the lungs daily. In addition, the considerable surface area represented by the endothelium of the pulmonary circulation is a site of synthesis and elimination, the implications of which are increasingly important in the area of the metabolism of endogenous substances: prostaglandins, vasomotor substances and the bioconversion of drugs and toxic agents. This is an increasingly large area of research and investigation, the clinical applications of which appear to be more and more frequent and important.

Arachidonic Acids↗

PubMed1984

Effect of exogenous surfactant on total respiratory system compliance.

We measured total respiratory system compliance (Crs) before and after instilling 25 mg artificial surfactant in 1 ml saline down the endotracheal tube of preterm babies requiring resuscitation at birth, and compared results with data from 6 similar babies receiving saline only. Surfactant did not produce a significant improvement in Crs.

Clinical Trials as Topic↗

PubMed2002

Effects of off-pump coronary surgery on the mechanics of the respiratory system, lung, and chest wall: Comparison with extracorporeal circulation.

OBJECTIVE: To compare the effects of cardiac surgery with and without extracorporeal circulation on the mechanics of the respiratory system, lung, and chest wall. We also determined the time course of those effects. DESIGN: Prospective, controlled study. SETTING: An eight-bed, cardiac-surgical intensive care unit at a university hospital. PATIENTS: Two groups of patients scheduled for elective coronary bypass surgery were studied: ten patients with extracorporeal circulation and 13 patients without extracorporeal circulation. INTERVENTIONS: Measurement of esophageal pressure after insertion of an esophageal balloon catheter to separate respiratory system mechanics into lung and chest wall components. Measurements were performed preoperatively after induction of anesthesia (control), immediately postoperatively at arrival in the intensive care unit (time 1), and after 3 hrs (time 2). In 12 of the 23 patients, measurements were also performed 6 hrs postoperatively (time 3). MEASUREMENTS AND MAIN RESULTS: No significant differences concerning demographics or surgical procedure were noticed between the two groups. Respiratory system, chest wall, and lung mechanics were obtained using the technique of rapid airway occlusion during constant-flow inflation. In both the group with and without extracorporeal circulation there was a significant increase in static and dynamic elastance of the respiratory system and lung at times 1 and 2, which tended to decrease again at time 3; chest wall elastance significantly increased at times 2 and 3 in the group without extracorporeal circulation, whereas the increase in chest wall elastance in the group with extracorporeal circulation occurred earlier (also at time 1). Additional resistance of the respiratory system and lung remained unchanged; chest wall resistance, however, significantly increased in both groups. Work of breathing significantly increased in both groups at times 1 and 2. There was a significant reduction in the Pao2/Fio2 ratio in both groups at times 2 and 3. No significant differences between the groups at any moment were noticed. CONCLUSIONS: Coronary bypass surgery with and without extracorporeal circulation results in dramatic impairment of respiratory system mechanics. Based on respiratory system mechanics, early extubation after coronary artery bypass grafting should be performed with caution, no matter whether the off-pump or cardiopulmonary bypass technique is used.

Aged↗

PubMedDate not supplied

Localized amyloidosis of the respiratory system: CT features.

PURPOSE: Amyloidosis includes a spectrum of diseases associated with an abnormal extracellular deposition of amyloid. The respiratory system is involved in approximately 50% of patients with amyloidosis. The purpose of this review is to present the CT findings of localized amyloidosis of the respiratory system. METHODS: We reviewed the CT findings of localized amyloidosis of the respiratory system from the previous reports and our experiences. RESULTS: Three patterns of involvement in respiratory system are presented: tracheobronchial nodular and diffuse parenchymal. CT demonstrates nodules, plaques, or diffuse thickening of the airways with calcification. Postobstructive collapse is associated in case of diffuse airway involvement. Parenchymal nodules have sharp and lobulated margins with peripheral or subpleural locations. High-resolution CT shows reticular opacities, interlobular septal thickening, and small, well-defined nodules of 2 to 4-mm in diameter predominantly in the subpleural regions. CONCLUSION: Amyloidosis of respiratory system has variable findings and CT scans clearly depict extent and distribution of the disease, its postobstructive pulmonary complication, and other associated findings such as calcification and lymphadenopathy.

Aged↗

PubMed2005

Respiratory system involvement in ANCA-associated systemic vasculitides.

BACKGROUND AND AIM OF THE WORK: The respiratory system may be involved in all systemic vasculitides (SV), although with a variable frequency. Lung disease is a very common and important feature of the antineutrophil cytoplasmic antibodies (ANCA)-associated SV (AASV), such as Wegener's granulomatosis (WG), Churg-Strauss syndrome (CSS), and microscopic polyangiitis (MPA). The aim of the work is to review the clinical findings, as well as the radiological and pathological features of respiratory system involvement in AASV. METHODS: A detailed search via the PubMed index from the National Library of Medicine, covering the period from 1980 to December 2004, was accomplished. RESULTS: In WG, almost all patients have either upper airway or lower respiratory tract disease. Solitary or multiple nodules and masses are the most common findings on chest radiograph. Asthma is a main symptom of CSS, often preceded by allergic rhinitis, frequently complicated by nasal polyposis and sinusitis. Pulmonary transient and patchy alveolar infiltrates are the most common radiographic findings. In MPA, diffuse alveolar haemorrhage (DAH) due to alveolar capillaritis is the most frequent manifestation of the respiratory involvement, clinically expressing with haemoptysis, respiratory distress and anaemia. CONCLUSIONS: The involvement of the respiratory system is a very common and important feature of AASV. There is substantial overlap in many of the clinical pulmonary features of AASV. In some cases, distinguishing between these diseases on the basis of the clinical features alone is difficult and pathological assessment is needed.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1994

The cyanide-metabolizing enzyme rhodanese in different parts of the respiratory systems of sheep and dog.

Studies on the rhodanese activity of respiratory systems of sheep and dog showed that a significant difference exists in the pattern of distribution of this enzyme in different parts of the respiratory system of both species. In sheep, larynx, trachea, bronchiole, and lung contain higher activity than nasal cavity and pharynx. In dog, significantly greater rhodanese activity was found in nasal cavity than in other parts of the respiratory system. In regions with high rhodanese activity the enzyme was more concentrated in the mucosa than in the underneath tissues. These results are discussed in terms of the possible role of rhodanese in cyanide metabolism in respiratory tract and the efficacy of this organ in inhaled cyanide detoxification in these species of animals.

Animals↗

PubMed1987

Respiratory system in amyotrophic lateral sclerosis.

Failure of the respiratory system is the most common cause of death in amyotrophic lateral sclerosis. This is due to weakened respiratory musculature resulting in respiratory failure, ineffective cough, and failure to protect the lungs from aspiration. Treatment is only supportive at present, but mechanical ventilation with either negative or positive pressure offer some life-extending possibilities. The respiratory system should be closely monitored as early identification of problems may allow better insight into the immediate prognosis.

Amyotrophic Lateral Sclerosis↗

PubMed1990

Flow and volume dependence of respiratory system mechanics during constant flow ventilation in normal subjects and in adult respiratory distress syndrome.

Seven control subjects and seven patients with adult respiratory distress syndrome (ARDS) were artificially ventilated and flow, volume, and tracheal pressure were monitored. Respiratory system resistance (Rrs,max) was partitioned into its homogeneous (Rrs,min) and uneven (Rrs,u) components. Respiratory system elastance (Ers) was also measured. In both groups Ers did not vary with different inspiratory flows and volumes, but was significantly higher in ARDS. With increasing volume (isoflow maneuvers), Rrs,max and Rrs,u increased but Rrs,min remained unaltered in ARDS. In control patients, however, resistances did not vary but Rrs,max and Rrs,u were smaller and Rrs,min equaled their corresponding values in ARDS. Hence, stress relaxation seems to be increased in ARDS. During isovolume maneuvers Rrs,max and Rrs,u decreased with increasing flows (both groups), although they were significantly higher in ARDS. Rrs,min was not modified by different flows and was similar in both groups. Thus, pendelluft is also increased in ARDS. In conclusion, the mechanical profile of ARDS is characterized by increased Ers and Rrs,max, the latter being secondary to augmented mechanical unevenness within the system.

Adolescent↗

PubMed1991

Effect of preoperative stabilization on respiratory system compliance and outcome in newborn infants with congenital diaphragmatic hernia.

To determine whether preoperative stabilization and delay of operative repair of congenital diaphragmatic hernia (CDH) may decrease operative risk, we performed serial pulmonary function tests on 22 newborn infants with CDH and on four infants without pulmonary hypoplasia (two with ileal atresia and two with tracheoesophageal anomalies) who served as control subjects. We used 2 passive respiratory mechanics technique to measure respiratory system compliance. All patients with CDH had respiratory distress immediately after birth, and required mechanical ventilation. Thirteen babies underwent emergency repair (six survived, seven died); nine of them received extracorporeal membrane oxygenation (ECMO) after the operation (two survived, seven died). Operative repair was delayed deliberately for 2 to 11 days in nine infants with severe hypoxemia. Six immediately received ECMO for 4 to 10 days; one died of intraventricular hemorrhage, and five survived and later underwent surgical repair. The seventh patient did not receive ECMO but appeared to have respiratory distress syndrome of infancy and improved after administration of synthetic surfactant. Improvement was seen in two additional infants who received conventional assisted ventilation during a 48-hour delay before surgery, and survived. In all, eight of nine infants who underwent preoperative stabilization survived (p less than 0.05 compared with survival after emergency surgery). Following surgical repair immediately after birth, respiratory system compliance improved only slightly during the first week of life, a time when control infants had a rapid increase in respiratory system compliance (p less than 0.001). In contrast, respiratory system compliance increased nearly twofold in the nine patients undergoing preoperative stabilization (p less than 0.02). Preoperative ECMO was associated with an increase in respiratory system compliance of more than 60% for 1 week, a significant difference from respiratory system compliance among patients undergoing emergency CDH repair (p less than 0.05). These observations provide physiologic evidence of possible benefits of preoperative stabilization before repair of CDH.

Extracorporeal Membrane Oxygenation↗

PubMed1988

Respiratory system, lung, and chest wall mechanics in guinea pigs.

1. Volume, airflow, tracheal, esophageal and transpulmonary pressures were measured in 6 mechanically ventilated, anesthetized and paralyzed guinea pigs. 2. The elastic and resistive properties of the respiratory system were partitioned into their lung and chest wall components a) following end-inflation occlusion of the airways subsequent to constant flow inspirations, and b) during relaxed expirations following release of occlusion. The values obtained by both methods were similar. 3. Mean respiratory system, lung and chest wall elastances were 3.518, 2.671, and 0.847 cm H2O/ml, respectively. 4. Mean respiratory system, pulmonary and chest wall resistances (at flows of 4.3 ml/s) were 0.302, 0.184, and 0.118 cm H2O ml-1 s, respectively. 5. Respiratory system, lung and chest wall resistances were partitioned into two components: 1) a homogeneous one whose values corresponded to 0.171, 0.095, and 0.076 cm H2O ml-1 s, for respiratory system, lung and chest wall, respectively, and 2) a component due to Pendelluft and stress relaxation and corresponding to 0.131, 0.089, and 0.042 cm H2O ml-1 s, respectively. 6. Resistive pressure vs flow relationships for the respiratory system, lung and chest wall were also determined during the entire tidal expiration. 7. We conclude that the chest wall participates significantly in respiratory system unevenness.

Airway Resistance↗

PubMed1997

Respiratory system mechanics in the early phase of acute respiratory failure due to severe kyphoscoliosis.

OBJECTIVE: To evaluate respiratory mechanics in the early phase of decompensation in a group of seven patients with severe kyphoscoliosis (KS) (Cobb angle > 90 degrees) requiring mechanical ventilatory support. DESIGN: Prospective clinical study with a control group. SETTING: General intensive care unit at University of Rome "La Sapienza". PATIENTS: Seven consecutive patients affected by severe KS in the early phase of acute decompensation and a control group of six ASA (American Society of Anesthesiology) 1 subjects who were mechanically ventilated during minor surgery. MEASUREMENTS AND RESULTS: Respiratory mechanics were evaluated during constant flow-controlled mechanical ventilation at zero end-expiratory pressure with the end-inspiratory and end-expiratory occlusion technique. In five patients who showed increased ohmic resistance (RRSmin), we evaluated the possibility of reversing this increase with a charge dose of 6 mg/kg doxophylline i.v. In four KS patients, in whom a reliable esophageal pressure was confirmed by a positive occlusion test, we separated respiratory system data into lung and chest wall component. All KS patients showed reduced values of respiratory compliance (CRS) and increased respiratory resistance (RRS). The average basal values of CRS were 36 +/- 10 vs 58 +/- 8.5 cmH2O in control patients; RRSmax was 20 +/- 3.1 vs. 4.5 +/- 1.2 cmH2O/1 per s; RRSmin 6.2 +/- 1.2 vs. 2 +/- 0.5 cmH2O/1 per s: delta RRS 14 +/- 2.6 cmH2O vs 2.4 +/- 0.7 cmH2O/1 per s. All KS patients showed low values of intrinsic positive end-expiratory pressure (PEEPi) (1.8 +/- 1.5 cmH2O). Separation of lung and chest-wall mechanics, performed only in four patients, showed a reduction in both lung (66.7 +/- 7.2 ml/cmH2O) and chest wall values (84 +/- 8.2 ml/cmH2O), while both RmaxL and RmaxCW were increased (16.6 +/- 2 and 2.8 +/- 0.4 cmH2O/1 per s, respectively). Infusion of doxophylline did not significantly change respiratory mechanics when evaluated 15, 30, and 45 min after the infusion. CONCLUSIONS: During acute decompensation, both lung and chest-wall compliance are severely reduced in KS patients: conversely, and, contrary to that in patients with chronic obstructive pulmonary disease, increases in airway resistance and PEEPi seem to play only a secondary role.

Airway Resistance↗

PubMed1994

Pressure-volume relationships of the respiratory system in normal cats.

We studied the pressure-volume (PV) relationships of the total respiratory system, lung and chest wall in 8 anesthetized and paralyzed normal adult cats. The PV relationships of the total respiratory system had a sigmoid shape with a relatively linear portion with an alveolar pressure between 0 to +15 cmH2O. The relative impact of the lung and chest wall to the total elastic recoil forces of the respiratory system was approximately equal within a physiological pressure range. The results suggest that measurements of PV relationships of the respiratory system may offer a physiologic basis for accurate interpretation of pulmonary functions, leading to a better therapeutic strategy in animals with lung diseases.

Animals↗

PubMed1979

Human and experimental data on translocation of asbestos fibers through the respiratory system.

The translocation of fibrous dusts through the respiratory system is discussed on the basis of human and experimental data obtained with the transmission electron microscope. Comparison of the characteristics (numerical and mass concentrations, sizes, types) of asbestos fibers retained in different locations of the respiratory system in humans exposed to asbestos has shown that there is no relationship between the numerical concentrations in lung parenchyma and those in parietal pleura. Moreover, almost al fibers encountered in the pleura were ultimate, short fibrils of chrysotile. The animal data are from rats injected intrapleurally with different types of fibers (chrysotile, crocidolite and glass fibers) and sacrificed at different times. There was a progressive increase in the number and mass of fibers translocated into lung parenchyma from the pleural cavity that was particularly obvious after 90 days. After this time, the mean length of fibers, especially chrysotile, increased, indicating that more long fibers are retained in alveolar tissue than short fibers.

Animals↗

PubMed1994

Effect of neuromuscular blockade on the elastic properties of the lungs, thorax, and total respiratory system in anesthetized pigs.

OBJECTIVE: To evaluate the effect of neuromuscular blockade on the elastic properties of the lungs, thorax, and total respiratory system in pigs anesthetized to suppress spontaneous breathing. DESIGN: Prospective, randomized, experimental study. SETTING: A research laboratory at a university medical center. SUBJECTS: Eight healthy, anesthetized pigs, weighing 22 to 25 kg. INTERVENTIONS: Pigs, with and without muscular blockade, were mechanically ventilated during an infusion of sodium pentobarbital that was titrated to suppress spontaneous breathing activity. MEASUREMENTS AND MAIN RESULTS: No significant differences were observed between pressure/volume curves of the lungs, the chest wall, and the total respiratory system, as determined by inflating and deflating the lungs during anesthesia, with or without neuromuscular blockade, in random order. Functional residual capacity was 985 +/- 87 mL with neuromuscular blockade and 997 +/- 78 mL without neuromuscular blockade (NS). A comparison of the total respiratory system, lung, and chest wall compliances obtained with and without neuromuscular blockade showed high correlations (total respiratory system compliance [r2 = .86]; chest wall compliance [r2 = .83]). CONCLUSION: Neuromuscular blockade does not alter the elastic properties of the lungs, chest wall, or total respiratory system in mechanically ventilated pigs receiving sodium pentobarbital anesthesia to suppress spontaneous breathing efforts.

Analysis of Variance↗

PubMed2005

[Spanish scientific production in diagnostic and therapeutic research area of respiratory system in international journals from 1990 to 2002].

OBJECTIVE: The aim of this study were: to analyze the spanish production in diagnostic and therapeutics research area of respiratory system in international journals from 1990 to 2002. MATERIAL AND METHODS: Papers published in diagnostic and therapeutics area of respiratory system during this period of time were selected by the PUBMED system. We delimited the production with key words: respiratory system and the one that is used by the diagnostic and therapeutics research area. RESULTS: We obtain a total of 67 document published in international journals by spanish authors. The scientific production in the diagnostic and therapeutics area have stabilized in this 12 years period. The distribution of articles by the institutional affiliation and province of authors also showed a wide dispersion: Barcelona and Clinic and Provincial Hospital of Barcelona were responsible for 43.1% and 23.8% of all the production. Bronchoalveolar lavage and the use of telescopic catheter were the type of diagnostic and therapeutic procedure more productive. CONCLUSIONS: The scientific production in the diagnostic and therapeutics area of respiratory system have stabilized in this 12 years period, this evidence contrast with the high growth detected in respiratory system in general.

Biomedical Research↗

PubMed2002

Mechanics of the respiratory system in the newborn tammar wallaby.

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 (V(O(2))) through the skin was approximately 33 % of the total V(O(2)) at day 1 and approximately 14 % at day 6. The mass-specific resting minute ventilation (E) and the ventilatory equivalent (VE/(O(2))) 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 (C(rs)) 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 (R(rs)) 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.

Airway Resistance↗

PubMed1988

[The respiratory center--the regulator of the respiratory system].

The authors consider the respiratory centre to be the regulator of the respiratory system and to consist of 3 main functional blocks: chemoregulator, respiratory rhythm autogenerator and mechanoregulator, functions of which are provided by the neurons of medulla oblongata. The main aim of chemoregulator block is to maintain the level of ventilation volume speed, which is necessary to compensate the difference between the signals of setting and the firing from the chemoreceptors. The main aim of mechanoregulator block is to provide the functioning of the regulation loop of the respiratory muscles comparing the signals which come from the respiratory autogenerator, and the firing of the mechanoreceptors. The generator unit of the respiratory centre is a set of rhythm-forming associations, the system of 4 neurons (early and late inspiratory and expiratory) are typical among them. The neurons are connected by recurrent inhibitory bonds: the neuron of each rhythm-forming group, successively becoming excited, inhibits the two preceding neurons in the cycle; for all this the neuron of the successive group is released from inhibition and in such a way the rhythmogenesis occurs. The respiratory centre forms a common unit for chemo- and mechanoreceptor loops, through which the circuits of feedback for both loops are connected, providing the regulation of breathing.

Animals↗