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Psychophysiology Jan 2005The role of emotions as potential triggers of asthmatic airway obstructions was examined by whole body plethysmography. Three affectively homogeneous picture series... (Clinical Trial)
Clinical Trial
The role of emotions as potential triggers of asthmatic airway obstructions was examined by whole body plethysmography. Three affectively homogeneous picture series (IAPS) were presented with video glasses to induce pleasant, unpleasant, and neutral emotional states in 32 asthmatic and 32 nonasthmatic participants while they were seated in a Jaeger Bodytest plethysmograph. Airway resistance, specific airway resistance, thoracic gas volume, and mood were measured immediately after each presentation, in addition to specific airway resistance before and during each presentation. Airway resistance and specific airway resistance were significantly increased after and during pleasant and unpleasant stimulation compared to neutral stimulation in asthmatic patients and also, but less pronounced, in nonasthmatic controls. The results show that the experience of pleasant and unpleasant emotions can provoke increased airway resistance especially in asthmatic patients.
Topics: Adult; Airway Resistance; Asthma; Autonomic Nervous System; Emotions; Female; Humans; Male; Plethysmography, Whole Body
PubMed: 15720584
DOI: 10.1111/j.1469-8986.2005.00263.x -
PloS One 2017Surgery patients in Japan undergo routine spirometry testing prior to general anesthesia. The use of a flow sensor during general anesthesia has recently become common.... (Observational Study)
Observational Study
Surgery patients in Japan undergo routine spirometry testing prior to general anesthesia. The use of a flow sensor during general anesthesia has recently become common. However, it is not certain whether the information derived from flow-volume curves is being adequately used for mechanical ventilation management during general anesthesia. So far, there have been no attempts to calculate airway resistance using flow-volume curves. Therefore, we performed a prospective, observational study to investigate the relationship between pre-anesthetic and intra-anesthetic airway resistance in patients scheduled for surgery under general anesthesia. We calculated pre-anesthetic and intra-anesthetic airway resistance in each patient, based on the slopes of flow-volume curves obtained prior to and during general anesthesia. We also calculated endotracheal tube resistance to correct the intra-anesthetic airway resistance values calculated. A total of 526 patients were included in the study, and 98 patients had a forced expiratory volume in the first second/forced vital capacity ratio of < 70%. Pre-anesthetic airway resistance was significantly higher in patients with airflow obstruction than in those without airflow obstruction (p < 0.001), whereas no significant difference in intra-anesthetic airway resistance was found between patients with and without airflow obstruction during mechanical ventilation (p = 0.48). Pre-anesthetic and intra-anesthetic airway resistance values were closer to each other in patients without airflow obstruction, with a mean difference < 1.0 cmH2O L-1s-1, than in those with airflow obstruction, although these respiratory parameters were significantly different (p < 0.001). Intra-anesthetic airway resistance was not related to the FEV1/FVC ratio, regardless of the degree to which the FEV1/FVC ratio reflected pre-anesthetic airway resistance. As compared with patients with airflow obstruction, the mean difference between pre-anesthetic and intra-anesthetic airway resistance was small in patients without airflow obstruction.
Topics: Adolescent; Adult; Airway Resistance; Anesthesia, General; Anesthetics, General; Forced Expiratory Volume; Humans; Prospective Studies; Respiration, Artificial; Spirometry; Tidal Volume; Vital Capacity
PubMed: 28212451
DOI: 10.1371/journal.pone.0172421 -
Neurophysiologie Clinique = Clinical... Dec 1998During polysomnography, measurement of airflow and respiratory effort are essential for classifying the type of respiratory event and for evaluating the efficacy of... (Review)
Review
During polysomnography, measurement of airflow and respiratory effort are essential for classifying the type of respiratory event and for evaluating the efficacy of treatment. There are various ways to measure respiratory effort, the reference technique being oesophageal manometry. This measures fluctuations in intrathoracic pressure which correspond to variations in upper airway resistance and therefore allows differentiation between central and obstructive respiratory events. Thus the simple snorer can be distinguished from an individual with the upper airway resistance syndrome (UARS). In the UARS abnormally high resistance develops in the upper airway in the absence of identifiable apnoeas and hypopnoeas. The characteristic cresendo-decresendo pattern of the oesophageal pressure signal, when associated with the micro-arousals which are responsible for the hypersomnolence, is pathognomonic of this condition. The clinical application of oesophageal manometry is limited by its poor tolerance in certain individuals and by the potential deleterious effect the catheter itself has on sleep quality and on the dynamics of the upper airway. Other less invasive techniques, such as nasal pressure and pulse transit time, are currently under evaluation.
Topics: Airway Resistance; Esophagus; Humans; Polysomnography; Respiratory Mechanics; Respiratory Muscles; Sleep
PubMed: 9894230
DOI: 10.1016/s0987-7053(99)80019-7 -
Journal of Applied Physiology... Feb 1991Extrathoracic airway (ETA) stability was tested by inspiratory flow-resistive loading in 10 preterm infants to determine whether ETA collapsibility was directly related...
Extrathoracic airway (ETA) stability was tested by inspiratory flow-resistive loading in 10 preterm infants to determine whether ETA collapsibility was directly related to the size of the added load. A fall in intraluminal pressure was produced by applying two inspiratory flow-resistive loads of lower (L1) and higher (L2) magnitudes. An increase in intrinsic resistance was used as an index of upper airway collapsibility. Total pulmonary resistance did not change from baseline with L1 (73 +/- 26 to 71 +/- 25 cmH2O.l-1.s) but increased significantly with L2 (72 +/- 21 to 99 +/- 34 cmH2O.l-1.s, P less than 0.02) secondary to a rise in inspiratory resistance (55 +/- 21 to 109 +/- 55 cmH2O.l-1.s, P less than 0.05). Expiratory resistance did not change significantly with either load. Proximal airway pressure was more negative with L2 than with L1 in every infant (mean -4.5 +/- 0.6 vs. -3.6 +/- 0.9 cmH2O, P less than 0.05). This study shows that the ETA of preterm infants is pressure passive at high but not at low collapsing pressures, and possible explanations include limited "active" compensation by upper airway dilator muscles and an overwhelming of the "passive" defense offered by the intrinsic rigidity of the ETA to large changes in transmural pressure.
Topics: Airway Resistance; Humans; Infant, Newborn; Infant, Premature; Pressure; Respiratory Function Tests; Respiratory Mechanics
PubMed: 2022582
DOI: 10.1152/jappl.1991.70.2.889 -
Respiratory Physiology & Neurobiology Jun 2002The flow resistance of the pulmonary airway tree (Raw) is disproportionately larger in large animals than in smaller ones. This is thought to be due to the fact that... (Comparative Study)
Comparative Study
The flow resistance of the pulmonary airway tree (Raw) is disproportionately larger in large animals than in smaller ones. This is thought to be due to the fact that smaller animals have relatively wider central airways than larger animals. However, Raw is not determined solely by the diameter of the main bronchi or trachea. It depends on the dimensions of all the individual airways and how they are connected. We investigated how the degree of asymmetry of the airway tree, the number of airway orders, and dimensions of the individual airways combine to determine Raw. We performed this investigation using computer models of the airway trees of two different sized isomorphic rodents that differ in weight by more than two orders of magnitude-the harvest mouse and the giant pouched rat. We calculated airway resistance in these models under various conditions, and confirmed that the smaller species has a lower Raw relative to body size than the larger species. We also showed that these differences are due to a combination of differences both in relative airway diameters and in the degree of asymmetry of the airway trees.
Topics: Airway Resistance; Animals; Body Constitution; Bronchi; Computer Simulation; Models, Biological; Muridae; Rats; Species Specificity
PubMed: 12093628
DOI: 10.1016/s0034-5687(02)00017-8 -
Turkish Journal of Medical Sciences Jun 2017Increased airway resistance reduces the effectiveness of ventilation treatment. Endotracheal tubes (ETTs) and connectors contribute to resistance. However, the effect of...
BACKGROUND/AIM
Increased airway resistance reduces the effectiveness of ventilation treatment. Endotracheal tubes (ETTs) and connectors contribute to resistance. However, the effect of a closed system suction (CSS) connector is not well known. We compared the in vivo resistance occurring with a CSS connector with that of the standard connector.
MATERIALS AND METHODS
This prospective study was conducted at Gazi University Hospital's neonatal intensive care unit. Intubated neonates were studied for two cycles; each cycle contained two periods of ETT + connector pairs (15 min/period) as follows: cycle 1 [A: long ETT + standard connector; B: long ETT + CSS connector] and cycle 2 [C: shortened ETT + standard connector; D: shortened ETT + CSS connector]. Resistance of 40 breaths/period was averaged for each case, and the means were analyzed by Wilcoxon test for pairwise comparisons between standard and CSS connectors. As each case provided two cycle data, 16 cycle data were compared.
RESULTS
The CSS connector increased resistance by 13.8% (range: 3.0%-22.1%) compared to the standard connector; P < 0.001. The resistance increase was similar between long [17.3% (range: 3.0%-17.7%)] and shortened ETTs [15.3% (range: 5.0%-29.6%)]; P = 0.834.
CONCLUSION
CSS connectors were found to increase airway resistance in ventilated neonates. The contribution of CSS should be considered during ventilation, particularly in the presence of difficulty in providing sufficient tidal volume.
Topics: Airway Resistance; Humans; Infant, Newborn; Prospective Studies; Respiration, Artificial; Suction
PubMed: 28618745
DOI: 10.3906/sag-1606-177 -
Journal of Applied Physiology... Jan 1991Although a thoracic volume dependence of upper airway resistance and caliber is known to exist in seated subjects, the mechanisms mediating this phenomenon are unknown....
Although a thoracic volume dependence of upper airway resistance and caliber is known to exist in seated subjects, the mechanisms mediating this phenomenon are unknown. To test the hypothesis that actively altered end-expiratory lung volume (EELV) affects upper airway resistance in the supine position and to explore the mechanisms of any EELV-induced resistance changes, we studied five normal males during wakefulness. Supraglottic upper airway resistance (Ruaw) was calculated at an inspiratory flow of 0.1 l/s. The genioglossal electromyogram was obtained with indwelling wire electrodes and processed as moving time average. End-tidal CO2 was monitored by infrared analyzer. Observations were made during four 20-breath voluntary maneuvers: two at high and two at low EELV in each subject. Each maneuver was preceded by a control period at functional residual capacity. At high lung volume the EELV was increased by 2.23 +/- 0.54 (SD) liters; Ruaw decreased to 67.8 +/- 35.1% of control, while tonic and phasic genioglossal activities declined to 79.0 +/- 23.1 and 72.4 +/- 29.8%, respectively. At low lung volume the EELV was decreased by 0.86 +/- 0.23 liters. Ruaw increased to 178.2 +/- 186.8%, while tonic and phasic genioglossal activities increased to 243.0 +/- 139.3 and 249.1 +/- 146.3%, respectively (P less than 0.0001 for all). The findings were not explained by CO2 perturbations or respiratory pattern. Multiple linear regression analysis indicated that the genioglossal responses blunted the EELV-induced changes in upper airway patency.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Adult; Airway Resistance; Electromyography; Humans; Lung Volume Measurements; Male; Middle Aged; Respiratory Muscles; Thorax
PubMed: 2010402
DOI: 10.1152/jappl.1991.70.1.430 -
Advances in Experimental Medicine and... 2008
Topics: Adult; Airway Resistance; Carbon Dioxide; Exhalation; Female; Humans; Hypocapnia; Inhalation; Male; Reference Values; Respiratory Mechanics; Tidal Volume
PubMed: 18085324
DOI: 10.1007/978-0-387-73693-8_87 -
Respiratory Physiology & Neurobiology Sep 2014In unrestrained whole body plethysmography, tidal volume is commonly determined using the barometric method, which assumes that temperature and humidity changes (the...
In unrestrained whole body plethysmography, tidal volume is commonly determined using the barometric method, which assumes that temperature and humidity changes (the 'barometric component') are solely responsible for breathing-related chamber pressure fluctuations. However, in small animals chamber pressure is also influenced by a 'mechanical component' dependent on airway resistance and airflow. We devised a novel 'mechanical lung' capable of simulating neonatal mouse breathing in the absence of temperature or humidity changes. Using this device, we confirm that the chamber pressure fluctuations produced by breathing of neonatal mice are dominated by the mechanical component, precluding direct quantitative assessment of tidal volume. Recognizing the importance of airway resistance to the chamber pressure signal and the ability of our device to simulate neonatal breathing at different frequencies and tidal volumes, we invented a novel in vivo, non-invasive method for conscious airway resistance and ventilation estimation (CARVE) in neonatal rodents. This technique will allow evaluation of developmental, pathological and pharmaceutical effects on airway resistance.
Topics: Airway Resistance; Animals; Animals, Newborn; Body Temperature; Computer Simulation; Consciousness; Lung Volume Measurements; Mice; Models, Biological; Physical Stimulation; Plethysmography; Respiratory Mechanics; Tidal Volume; Ventilators, Mechanical
PubMed: 25017785
DOI: 10.1016/j.resp.2014.07.004 -
Anesthesia and Analgesia Apr 1989The effect of aerosolized ketamine hydrochloride was investigated by measuring airway resistance with a two-compartment plethysmograph in guinea pigs challenged with...
The effect of aerosolized ketamine hydrochloride was investigated by measuring airway resistance with a two-compartment plethysmograph in guinea pigs challenged with histamine. In the first phase of the study, treatment with ketamine prior to histamine challenge did not protect against elevation of airway resistance. In the second phase of the study, ketamine inhalation after histamine challenge did not significantly diminish airway resistance. Aerosolized ketamine is not recommended for use in human subjects with asthma.
Topics: Aerosols; Airway Resistance; Animals; Bronchi; Female; Guinea Pigs; Isoproterenol; Ketamine
PubMed: 2929983
DOI: No ID Found