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At least 649 records · Page 36Linked to original sources
PubMed2004

Iatrogenic-induced dysfunction of the neuromuscular respiratory system.

In the presence of respiratory symptoms that are associated with alveolar hypoventilation or a restrictive ventilatory defect and in the absence of parenchymal or pleural abnormalities on the chest radiograph, iatrogenic causes must be evoked, exactly as they are in the presence of interstitial lung disease. In most cases, the anamnestic and clinical contexts provide a strong diagnostic presumption. It is important to establish carefully the mechanism of the observed disorders, using the currently available arsenal of diagnostic tools for clinical and prognostic reasons and from a medicolegal standpoint. It is necessary to evaluate precisely the clinical repercussions of the respiratory neuromuscular abnormality to serve as a basis for follow-up and to discuss therapeutic options in certain cases (eg, nocturnal ventilation to correct nocturnal hypoventilation due to diaphragmatic dysfunction, diaphragm plication to alleviate dyspnea after complete phrenic nerve destruction, phrenic nerve pacing), again in the perspective of medicolegal actions.

Diaphragm↗
PubMed2000

The respiratory system in spinal cord injury.

Respiratory complications are a leading cause of morbidity and mortality during the acute and chronic phases after spinal cord injury (SCI). This article reviews the respiratory impairments resulting from SCI and discusses a range of management strategies to be considered from the acute care phase through long-term follow up. The treatment of specific complications and preventive measures are reviewed.

Humans↗
PubMed1989

Inertance of the respiratory system in ponies.

The purpose of the present work was to measure the pulmonary inertance (IL) in ponies and to analyze its potential influence on the mechanics of breathing and on their aptitude to increase ventilation during exercise. Five healthy ponies 2.4-4 yr old [mean wt 255 +/- 15 (SE) kg] were used. On the one hand, inertance of the respiratory system (Irs) was computed from the value of the resonant frequency (fr) measured by the forced oscillation technique. On the other hand, respiratory airflow, tidal volume (VT), and transpulmonary pressure (PL) changes were recorded while the ponies were performing a light treadmill exercise, and IL was calculated as the ratio of the associated differences in inertial pressure (delta Pin) to volume acceleration (delta V). Respiratory airflow and VT were measured with a Fleisch pneumotachograph (no. 5) and PL with an intraesophageal balloon catheter. First, the protocol was carried out with the ponies breathing air and He-O2, second, while the ponies breathed through two additional tubes (100 cm long, 3 cm ID), then one, and finally none, fixed on the Fleisch pneumotachograph. Finally, the contribution of the extra- vs. the intrathoracic airways to IL was estimated by measuring the lateral midtracheal pressure recorded simultaneously with the aforementioned parameters. The values of Irs calculated with fr and of IL calculated on the basis of the delta Pin-delta V ratio were 29.8 +/- 0.4 and 19.8 +/- 1.0.10(-4) kPa.l-1.s-2, respectively. During He-O2 breathing IL decreased about three times; this result was similar to the predicted decrease based on gas density only.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

[Changes of respiratory system compliance by closure of congenital abdominal wall defects and postoperative complications].

We treated four neonates with congenital abdominal wall defects and performed pulmonary function testing before and after closure of abdominal wall defects. Pulmonary mechanics were measured by passive occlusion technique. Static respiratory system compliance (Crs) was 0.61 +/- 0.16 ml.cmH2O-1 .kg-1 (mean +/- SD) preoperatively and decreased to 0.31 +/- 0.03 ml.cmH2O-1.kg-1 postoperatively. Two cases with a marked decrease in Crs after the abdominal wall closure seemed to have longer intubation time and N.P.O period and to have more complications than with the other two cases. Our experience provides an evidence that Crs measurement could be a useful index in decision-making of the treatment of neonates with congenital abdominal wall defects.

Abdominal Muscles↗
PubMed1989

Factors affecting respiratory system stability.

Periodic breathing (recurrent central apneas) occurs frequently during sleep. Periodic breathing can arise as a result of unstable behavior of the respiratory control system. A mathematical model of the respiratory control system was used to investigate, systematically, the effect of severity of disturbances to respiration and certain system parameters on periodic breathing occurring during sleep. The model consisted of multi-compartment representation of O2 and CO2 stores, a peripheral controller sensitive to O2 and CO2, and a central controller sensitive to CO2. The effects of hypoxia and hypercapnia on the upper airway muscles were not considered in the model. Episodes of hyperventilation or asphyxia were used to disturb the control system and explore the boundaries of stable breathing. Circulation time and metabolic rate were also varied. Simulations with the model produced the following findings: The number of central apneas associated with periodic breathing were greater as circulation time increased; controller gain increases also made the number of apneas greater, although periodic breathing occurs with lower controller gains as circulation time increases. At each level of circulation time there was a range of controller gain changes which caused little change in the number of apneas. There were more apneas with hypoxia; also the number of apneas increased with sleep-associated reductions in metabolic rate. The more rapidly resting PCO2 rose at sleep onset, the greater the likelihood of recurrent apneas. Finally, the more intense the disturbance, the more apneas there were.

Chemoreceptor Cells↗
PubMed1992

Assessment of the ruminant respiratory system.

With practice, complete use of the methods of this assessment: history, detailed examination of the head and neck, cough induction, chest auscultation and percussion, and chest auscultation following forced rebreathing can be completed within 10 minutes. The examination can provide a great deal of new information regarding the respiratory system that would go undetected on a more general physical examination. In cases in which the diagnosis is still in question or requires confirmation, this will also enable the optimal use of appropriate ancillary tests, as described in the article on ancillary testing for the respiratory tract elsewhere in this issue.

Animals↗
PubMed1977

[Long term effects of low concentrations of noxious gases on the respiratory system: results of an epidemiological study among iron mines workers in Lorraine (France). (author's transl)].

An epidemiological study of 1,178 iron-mine workers in the Lorraine basin was conducted in order to assess the long-term effects on the respiratory system of low concentrations of noxious gases produced by the machinery and explosives in use. The subjects were selected at random from 5,300 workers who were aged between 35 and 55, had been in the mines for at least five years and who were free from radiological abnormalities such as siderosis, tuberculosis, fractured ribs, etc. For each subject a standard questionnaire (E.C.S.C. bronchitis/emphysema questionnaire) was completed and a clinical examination was performed along with the following tests-vital capacity; forced expiratory volume in 1 second; residual volume; acetylcholine test; steady state CO test for calculation of total and partial transfer functions. A venous blood sample for the determination of blood CO was taken as the subject left his place of work.

Adult↗
PubMed1989

Comparison of two airway occlusion methods for determining the compliance of the respiratory system (Crs) in newborn infants.

We investigated 11 spontaneously newborn infants (birth weight 1400 to 3120 g) on their first day of life. Measuring inspired gas volume (VI) and the mouth pressure obtained at inspiratory airway occlusion (Pocc) we calculated the compliance of the respiratory system (Crs): a) by linear regression analysis of the VI/Pocc measurements obtained at various VI (Olinsky, et al., 1976) and b) as the mean of 3 endinspiratory VI/Pocc measurements (modified airway occlusion method (Simbruner et al., 1982). There was a close linear correlation between the Crs values obtained by both methods (r = 0.98, p less than 0.001; Crs(a) = 0.669 x Crs(b) + 0.428), indicating that the simpler modified airway occlusion method (b) may be used instead of the original method (a) for determining Crs on the first day of life in spontaneously breathing newborn infants.

Airway Resistance↗
PubMed2002

[Air pollution--impact on the human respiratory system].

Authors present the problem of air-pollution in Central Europe at the turn of centuries. The main sources (natural & antropogenic), main types of pollutants (particularly SO2 and O3), WHO atmospheric air quality Guidelines, outdoor & indoor air pollution, episodic and chronic consequences and mechanisms with clinical effects of air pollution on the respiratory system (function, self-defence) were shortly performed).

Air Pollutants↗
PubMed1987

Regulatory peptides in the respiratory system.

Many regulatory peptides have been described in the respiratory tract of animals and humans. Some peptides (bombesin, calcitonin, calcitonin gene-related peptide) are localised to neuroendocrine cells and may have a trophic or transmitter role. Others are localised to motor nerves. Vasoactive intestinal peptide and peptide histidine isoleucine are candidates for neurotransmitters of non-adrenergic inhibitory fibres and may be cotransmitters in cholinergic nerves. These peptides may regulate airway smooth muscle tone, bronchial blood flow and airway secretions. Sensory neuropeptides (substance P, neurokinin A and B, calcitonin gene-related peptide) may contract airway smooth muscle, stimulate mucus secretion and regulate bronchial blood flow and microvascular permeability. If released by an axon reflex mechanism these peptides may be involved in the pathogenesis of asthma. Other peptides, such as galanin and neuropeptide Y, are also present but their function is not yet known.

Animals↗
PubMed1989

The epidemiology of the morbidity of respiratory system malignant neoplasm in Poland on the background of the increasing atmospheric air pollution by dust and vehicle exhaust emission.

This research work has been carried out on relationship between an increasing air pollution rate caused by dust and vehicle exhaust emissions and a rising morbidity of respiratory system malignant neoplasm in Poland in the years 1956-1982. The calculated correlation coefficients (r) are for vehicle exhausts--0.965 and for dust emissions--0.946. Those coefficients indicate the relationship between the investigated phenomena at the significance level of P less than 0.001.

Air Pollutants↗
PubMed1993

Effect of endurance physical training on cardio-respiratory system reactive features (mechanisms of training load cumulation influence)

The results of a series of experiments carried out under heavy physical loads during the training of 96 elite cyclists, rowers and swimmers were based on the following: (1) complex analysis of dynamics of sensitivity, stability and speed of responses of cardio-respiratory system (CRS) to hypoxia, CO2-H+ ionic irritants; (2) neurogenic (working) response stimuli; (3) range of changes in ventilatory, circulatory and metabolic responses and their dynamic characteristics. It was demonstrated that sensitivity, stability and speed of responses to shifts in respiratory homeostasis changed during each physical load and in the process of training. The nature and the extent of changes are connected with the intensity of the load as well as its type and duration. After training, we observed changes in the sensitivity, stability and response speed of CRS to shifts in respiratory homeostasis; we also noted that the total reactivity changes revealed the same direction of change as the above mentioned CRS physiological reactivity parameters. It was also observed that the dynamics of reactivity changes to hypoxia, CO2-H+ irritants and neurogenic CRS response are connected to the dynamics of peak of CRS response to physical load and to its stability and response speed. These results indicate the existence of certain mechanisms which regulate the setting up of the functional capacity in athletes.

Adaptation, Physiological↗
PubMed2004

Dynamic behavior of respiratory system during nasal continuous positive airway pressure in spontaneously breathing premature newborn infants.

The end-expiratory lung-volume level of premature newborn infants is maintained above passive resting volume during active breathing, through the combination of reduced time constant and high respiratory rate. To determine whether nasal continuous positive airway pressure (NCPAP) alters this characteristic dynamic breathing pattern, we studied the effects of various NCPAP levels on the dynamic elevation of end-expiratory lung volume level (DeltaEELV) in spontaneously breathing premature newborn infants, using respiratory inductive plethysmography (RIP). Eleven premature newborn infants with moderate respiratory failure were included. NCPAP levels were set in a random order to 0, 2, 4, and 6 cm H2O. Tidal volume (Vt), rib-cage contribution to Vt (%RC), phase angle between abdominal and thoracic motions (theta), respiratory rate (RR), and inspiratory and expiratory times (Ti and Te) were continuously recorded by RIP. The slope of the linear part of the expiratory flow-volume relation was extrapolated up to zero flow level to evaluate the dynamic elevation of the functional residual capacity (FRC) (DeltaEELV). The time-constant of the respiratory system (tauRS) was calculated as the slope of the linear part of the expiratory flow-volume loop. At NCPAP = 6 cm H2O, DeltaEELV reached 0.6 +/- 0.2 times the Vt at NCPAP = 0 cm H2O. An increase in NCPAP level resulted in a significant decrease in DeltaEELV (P < 0.01). A decrease in DeltaEELV during NCPAP was associated with a significant increase in Te from 0.62 +/- 0.13 sec at NCPAP = 0 cm H2O to 0.80 +/- 0.07 sec at NCPAP = 6 cm H2O (P < 0.05), and a decrease in tauRS from 0.4 +/- 0.1 sec at NCPAP = 0 cm H2O to 0.24 +/- 0.04 sec at NCPAP = 6 cm H2O (P < 0.01). These results indicate that the characteristic spontaneous breathing pattern causing a dynamic elevation of FRC is abolished by NCPAP. We speculate that the dynamic volume-preserving mechanisms resulting from expiratory flow braking are no longer required during NCPAP, as the constant pressure may passively elevate FRC.

Female↗