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American Journal of Respiratory and... Aug 2000
Topics: Airway Resistance; Humans
PubMed: 10934050
DOI: 10.1164/ajrccm.162.2.hh08-00 -
Respiratory Physiology & Neurobiology Dec 2021This study aimed to evaluate the accuracy of expiratory time constant (RC) to continuously calculate the airway resistance (R).
BACKGROUND
This study aimed to evaluate the accuracy of expiratory time constant (RC) to continuously calculate the airway resistance (R).
MATERIAL AND METHODS
A Respironics V60 ventilator was connected to a lung simulator for modeling different profiles of respiratory mechanics.
RESULTS
During assisted ventilation, the respiratory system compliance (C) calculation was always overestimated in most lung models. The R estimation using the expiratory resistance (R) method was close to the calculated value with the occlusion method during volume-controlled ventilation (VCV). In expiratory flow limitation (EFL) lung models, similar results were obtained in the estimation of inspiratory resistance (R), but different variations were observed in the calculation of the R. The results estimated with RC and with dynamic signal analysis had significant variation and accuracy (p < 0.001).
CONCLUSION
The RC method is a robust approach to provide real-time assessments of R and R in spontaneously breathing patients during noninvasive ventilation. An underestimation of R was observed in EFL lung models.
Topics: Airway Resistance; Humans; Lung; Models, Biological; Noninvasive Ventilation; Respiratory Mechanics
PubMed: 34242813
DOI: 10.1016/j.resp.2021.103738 -
American Journal of Respiratory and... May 2014
Topics: Airway Resistance; Female; Humans; Lung; Male; Respiratory Tract Diseases; Tidal Volume
PubMed: 24787064
DOI: 10.1164/rccm.201403-0543ED -
Seminars in Fetal & Neonatal Medicine Aug 2016Differences between neonatal, pediatric and adult airway anatomy, structure and function are important to understand. Size, surface area, proportion, resistance and... (Review)
Review
Differences between neonatal, pediatric and adult airway anatomy, structure and function are important to understand. Size, surface area, proportion, resistance and compliance are all very different between age groups and infants are certainly not small adults. Knowledge of these airway differences is essential in rapid correction of an emergency situation. Unanticipated airway emergencies are the most serious of all and may be classified into profiles such as the unanticipated emergency in the non-intubated patient, the unanticipated emergency in the intubated patient, and patients with tracheostomy. A neonatal airway emergency can be effectively managed by a strategy for anticipation, identification, preparation, mobilization, and execution. Furthermore, neonatal airways may be classified by severity in being considered either difficult or critical. These neonatal specific clinical challenges have recently substantiated the need for a distinct neonatal airway algorithm. This strategy is strengthened by regular education of the team and frequent simulation of airway emergencies. Following a predetermined pathway for activating an airway emergency alert and having all necessary equipment readily available are essential components of a well-defined strategy. Finally, knowing the pediatric otolaryngologist's perspective of what defines these airway disorders and current management is key to working collaboratively.
Topics: Airway Resistance; Humans; Infant, Newborn; Intubation, Intratracheal; Respiration Disorders; Respiratory System; Tracheostomy
PubMed: 27039115
DOI: 10.1016/j.siny.2016.03.004 -
Respiratory Physiology & Neurobiology Jun 2015In healthy Vietnamese children the respiratory resistance has been suggested to be similar at 110 cm height but larger at 130 cm when compared with data in Caucasians...
In healthy Vietnamese children the respiratory resistance has been suggested to be similar at 110 cm height but larger at 130 cm when compared with data in Caucasians from the literature, suggesting smaller airways in older Vietnamese children (Vu et al., 2008). The hypothesis tested here is whether the difference in airway resistance remains consistent throughout growth, and if it is larger in adult Vietnamese than in Caucasians. Airway resistance and Functional Residual Capacity were measured in healthy young Caucasian and Vietnamese adults in their respective native country using identical equipment and protocols. Ninety five subjects in Vietnam (60 males) and 101 in France (41 males) were recruited. Airway resistance was significantly larger in Vietnamese than in Caucasians and in females than in males, consistent with difference in body dimensions. Specific airway resistance however was not different by ethnicity or gender. The findings do not support the hypothesis that airway size at adult age - once normalized for lung volume - differs between Vietnamese and Caucasians.
Topics: Adolescent; Adult; Airway Resistance; Asian People; Female; France; Humans; Male; Multivariate Analysis; Plethysmography; Sex Characteristics; Vietnam; White People; Young Adult
PubMed: 25796614
DOI: 10.1016/j.resp.2015.03.002 -
Respiratory Care Clinics of North... Jun 1997Resistance measurements are the most useful parameters for assessing acute changes in airway caliber associated with bronchodilation or bronchial provocation. Used in...
Resistance measurements are the most useful parameters for assessing acute changes in airway caliber associated with bronchodilation or bronchial provocation. Used in addition to spirometry, Raw can provide a better differentiation of the causes of airflow impairment as well as the presence of concurrent processes. A simple, noninvasive Raw measurement can provide definitive answers in the absence of other changes. Finally, the addition of practical, nonplethysmographic measurements opens a new application for bedside, office, and home monitoring.
Topics: Airway Resistance; Bronchial Provocation Tests; Humans; Lung Diseases, Obstructive; Monitoring, Physiologic; Plethysmography; Respiratory Function Tests; Spirometry
PubMed: 9390910
DOI: No ID Found -
Journal of Applied Physiology... Aug 1994To quantify the contribution of lung volume dependence of upper airway (UA) on continuous negative airway pressure (CNAP)-induced increase in upper airway resistance, we... (Comparative Study)
Comparative Study
To quantify the contribution of lung volume dependence of upper airway (UA) on continuous negative airway pressure (CNAP)-induced increase in upper airway resistance, we compared the changes in supralaryngeal resistance during an isolated decrease in lung volume and during CNAP in eight normal awake subjects. Inspiratory supralaryngeal resistance was measured at isoflow during four trials, during two CNAP trials where the pressure in a nasal mask was progressively decreased in 3- to 5-cmH2O steps and during two continuous positive extrathoracic pressure (CPEP) trials where the pressure around the chest (in an iron lung) was increased in similar steps. The CNAP and CPEP trials were done in random order. During the CPEP trial, the neck was covered by a rigid collar to prevent compression by the cervical seal of the iron lung. In each subject, resistance progressively increased during the experiments. The increase was linearily correlated with the pressure increase in the iron lung and with the square of the mask pressure during CNAP. There was a highly significant correlation between the rate of rise in resistance between CNAP and CPEP: the steeper the increase in resistance with decreasing lung volume, the steeper the increase in resistance with decreasing airway pressure. Lung volume dependence in UA resistance can account for 61% of the CNAP-induced increase in resistance. We conclude that in normal awake subjects the changes in supralaryngeal resistance induced by CNAP can partly be explained by the lung volume dependence of this resistance.
Topics: Adult; Airway Resistance; Female; Humans; Larynx; Lung; Lung Volume Measurements; Male; Positive-Pressure Respiration; Ventilators, Negative-Pressure
PubMed: 8002537
DOI: 10.1152/jappl.1994.77.2.840 -
The European Respiratory Journal Dec 2016
Topics: Airway Resistance; Asthma; Child; Child, Preschool; Feasibility Studies; Female; Humans; Male; Plethysmography; Respiration
PubMed: 27824605
DOI: 10.1183/13993003.01302-2016 -
International Journal of Chronic... 2023Specific resistance (SR) measurements in Chronic Obstructive Pulmonary Disease (COPD) patients may be performed by panting or tidal breathing. The aim of this study was...
INTRODUCTION
Specific resistance (SR) measurements in Chronic Obstructive Pulmonary Disease (COPD) patients may be performed by panting or tidal breathing. The aim of this study was to compare how breathing frequency affected SR in COPD and compare different tangent plotting methods.
METHODS
Fifteen COPD patients participated. Three protocols were performed: tidal 1 - spontaneous tidal breathing; tidal 2 - tidal breathing with a flow of ±1 L/sec; panting - 60 breaths per min. Effective (SR), total (SR), ±0.5 L/s (SR), and mid (SR) specific resistance were assessed.
RESULTS
The tidal breathing protocols provided similar results. Panting resulted in higher SR (p = 0.0002) and SR (p < 0.0001) versus tidal breathing, but not SR or SR. Breathing frequency did not affect intra-test variance. SR and SR measurements were similar, and were higher than SR, during tidal breathing (p = 0.0014 and p < 0.0001 respectively) and panting (p = 0.0179 and p < 0.0001 respectively). SR was higher than SR during tidal breathing (p < 0.0001) and panting (p < 0.0001). Intra-test variance of SR and SR were similar and showed the lowest percent coefficient of variation during both tidal breathing and panting.
CONCLUSION
Panting and tidal breathing manoeuvres are not interchangeable in COPD patients. Panting widens the clubbing in the SR loop. SR and SR may underestimate abnormal physiology in COPD.
Topics: Humans; Pulmonary Disease, Chronic Obstructive; Airway Resistance; Respiratory Function Tests; Respiration; Respiratory System
PubMed: 38022825
DOI: 10.2147/COPD.S424696 -
American Journal of Physiology. Lung... Mar 2011
Topics: Airway Resistance; Bronchial Hyperreactivity; Humans; Plethysmography; Respiratory Function Tests
PubMed: 21368020
DOI: 10.1152/ajplung.00410.2010