-
Respiratory Physiology & Neurobiology Jul 2019Prolonging the therapeutic window for treatment is imperative for survival from a multitude of life-threatening events such as hemorrhage, cardiac arrest, and stroke.... (Review)
Review
Prolonging the therapeutic window for treatment is imperative for survival from a multitude of life-threatening events such as hemorrhage, cardiac arrest, and stroke. Inspiratory resistance breathing is a therapeutic approach that augments the reduction in intrathoracic and intracranial pressure during inspiration, facilitating improvements in vital organ perfusion under conditions of ischemia, such as blood loss and cardiac arrest. In this review a series of studies will be presented assessing the role of inspiratory resistance breathing on responses of cerebral blood flow and cerebral tissue oxygenation under conditions of cardiac arrest and blood loss in animal models, and simulated hemorrhage in humans. Knowledge gaps in this field of investigation will be presented, and future research directions will be discussed.
Topics: Airway Resistance; Animals; Arterial Pressure; Cardiovascular Diseases; Cerebrovascular Circulation; Cerebrum; Hemorrhage; Humans; Intracranial Pressure; Oxygen; Respiration
PubMed: 30340016
DOI: 10.1016/j.resp.2018.10.001 -
The Journal of Laryngology and Otology Jul 2021Electronic cigarettes have been a popular alternative to tobacco smoking. The effect of tobacco smoking on nasal airway resistance has been investigated before; however,...
BACKGROUND
Electronic cigarettes have been a popular alternative to tobacco smoking. The effect of tobacco smoking on nasal airway resistance has been investigated before; however, the effect of the aerosol generated by electronic cigarettes is still unknown. This study aimed to evaluate the short-term effects of e-cigarettes on nasal airway resistance.
METHODS
Sixty-one participants were recruited into a vapers group and a control group. The vapers group was instructed to smoke for 5 minutes, and their nasal resistance was measured pre-procedure and at 1 and 5 minutes post-procedure. The results were compared between both groups.
RESULTS
Repeated measures analysis of variance demonstrated that vaping has no statistically significant effect on total nasal airway resistance.
CONCLUSION
Although the differences between both groups were not statistically significant overall, the vapers group showed a reduction in nasal airway resistance in the short term.
Topics: Adolescent; Adult; Airway Resistance; Case-Control Studies; Cross-Sectional Studies; Electronic Nicotine Delivery Systems; Female; Humans; Male; Middle Aged; Nasal Cavity; Rhinomanometry; Vaping; Young Adult
PubMed: 34078481
DOI: 10.1017/S0022215121001432 -
PloS One 2022Obesity can increase the airways resistance, mainly in the periphery, leading to dyspnea perception that can impair the functional capacity. This study aimed to analyze...
BACKGROUND AND OBJECTIVE
Obesity can increase the airways resistance, mainly in the periphery, leading to dyspnea perception that can impair the functional capacity. This study aimed to analyze if airways resistance could be related to the walking capacity of women with morbid obesity.
METHODS
Thirty-seven women with grade III obesity in preoperative bariatric surgery were evaluated using the spirometry test, impulse oscillometry system (IOS), and six-minute walk test (6MWT). Additionally, data about their daily dyspnea perception and physical activity level were collected.
RESULTS
Variables of the spirometry test did not detect ventilator disorders. Compared to the predicted values, the IOS identified significant increase in airways resistance (kPa/L/s) (R5: 0.36 (0.34; 0.36) and 0.53 (0.47; 0.61); R20: 0.30 (0.28; 0.30) and 0.41 (0.35; 0.45); R5-20: 0.06 (0.06; 0.06) and 0.14 (0.10; 0.15); X5: -0.03 (-0.04; -0.01) and -0.20 (-0.27; -0.18), respectively). The distance walked in the 6MWT, 491.4±60.4m was significantly correlated to R5 (rho = -0.41, p = 0.01), R5-20 (rho = -0.52, p = 0.001), and X5 (rho = 0.54, p = 0.0006).
CONCLUSION
The IOS is able to identify changes in airway resistance even before the onset of symptoms. When evaluated by IOS women with severe obesity and normal spirometry exhibited central and peripheral airways obstruction. The correlations between the IOS and six-minute walk distance suggest that increased peripheral airways resistance could be related to worsening functional capacity.
Topics: Airway Resistance; Dyspnea; Female; Forced Expiratory Volume; Humans; Lung; Obesity; Oscillometry; Pulmonary Disease, Chronic Obstructive; Spirometry
PubMed: 35671283
DOI: 10.1371/journal.pone.0267546 -
The Laryngoscope Jan 2022Nasal diseases are among the main motives for the early discontinuation of continuous positive airway pressure therapy and for long-term therapeutic compliance with... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
Nasal diseases are among the main motives for the early discontinuation of continuous positive airway pressure therapy and for long-term therapeutic compliance with mandibular advancement device. Although our clinical experience leads us to the belief that recumbency impacts nasal airflow in some patient populations, there is no consensus regarding the magnitude of this effect and the specific group of patients who are the most affected by this condition. In this study, we conducted a meta-analysis to assess the effect of the recumbent position on nasal resistance and nasal airflow.
REVIEW METHODS
PubMed (Medline), Cochrane Library, EMBASE, Scopus, and SciELO databases were checked for relevant studies by two members of the YO-IFOS study group. The two authors extracted the data. The main outcome was expressed as the difference between nasal resistance and nasal airflow before and after recumbency.
RESULTS
Nine studies with a total population of 291 individuals were included in the meta-analysis for nasal resistance after recumbency. We found a statistically significant difference in nasal airway resistance of -0.18 Pa sec/cm as compared to before and after recumbency through rhinomanometry (RMM) analysis. A subgroup analysis revealed a variation of -0.20 Pa sec/cm for patients with snoring or sleep apnea and - 0.10 Pa sec/cm for healthy individuals. Regarding nasal airflow measured with RMM, three studies (n = 32) in asymptomatic controls revealed a statistically significant difference of 47.33 ml/sec.
CONCLUSIONS
Recumbency increases nasal resistance and diminishes nasal airflow. This finding is of utmost importance in snorers and sleep apnea patients. Laryngoscope, 132:6-16, 2022.
Topics: Airway Resistance; Humans; Nasal Cavity; Supine Position
PubMed: 33720430
DOI: 10.1002/lary.29509 -
Pediatric Pulmonology Nov 2015The forced oscillation technique (FOT) may be affected by the upper airway artifact in children with airway obstruction. The aim was to test the impact of the artifact...
BACKGROUND
The forced oscillation technique (FOT) may be affected by the upper airway artifact in children with airway obstruction. The aim was to test the impact of the artifact on FOT ability to diagnose asthma in children as recommended by current guidelines.
METHODS
The FOT was performed in 58 asthmatics and 27 controls before and after salbutamol. Respiratory resistance (Rrs) was measured at 8 Hz with a standard generator (SG), and a head generator (HG) that minimizes the upper airway artifact. The response to salbutamol was computed as change in respiratory resistance (Δ%Rrs) and admittance (Δ%Ars) that almost cancels the effect of the upper airway artifact.
RESULTS
Rrs and Δ%Rrs were significantly larger in patients than controls by HG (respectively P < 0.001 and P = 0.002) but not SG, while Δ%Ars was larger in asthma than control by both (P < 0.04). Best discriminators between patients and controls were Rrs or Δ%Rrs by HG and Δ%Ars by SG.
CONCLUSION
In asthmatic children, the upper airway artifact significantly impacts FOT measurements. The diagnostic value may be improved by minimization of the shunt, such as the computation of Δ%Ars.
Topics: Airway Obstruction; Airway Resistance; Albuterol; Asthma; Bronchodilator Agents; Child; Female; Humans; Male; Treatment Outcome
PubMed: 25384559
DOI: 10.1002/ppul.23131 -
Minerva Dental and Oral Science Feb 2023The aim of this study was to test whether rapid palatal expansion is effective to improve nasal airway patency in a sample of pediatric patients with primary snoring.
BACKGROUND
The aim of this study was to test whether rapid palatal expansion is effective to improve nasal airway patency in a sample of pediatric patients with primary snoring.
METHODS
A group of 21 subjects, 11 girls (52%) and 10 boys (48%), with a mean age of 7.1 years (SD=1.3; range 4-9 years) were treated with a rapid maxillary expansion (RME) device. Nasal airway resistance was assessed via rhinomanometric exam before (pre-) and 6 months after (post-) the rapid palatal expansion treatment.
RESULTS
Data analysis showed a statistically significant increase in the mean scores of the results of the rhinomanometric exam between the pre- and post-measurements with a significant reduction in total inspiratory and expiratory air resistance values after rapid palatal expansion.
CONCLUSIONS
Our results show that RME treatment is associated with an improvement in nasal airway resistance due to a substantial reduction in nasal resistance associated with the orthopedic action of the orthodontic device.
Topics: Child; Female; Humans; Male; Airway Resistance; Nasal Cavity; Nose; Palatal Expansion Technique; Snoring; Rhinomanometry
PubMed: 36345835
DOI: 10.23736/S2724-6329.22.04727-1 -
Aerospace Medicine and Human Performance Nov 2018Performing at high altitude and scuba diving impose functional limitations to the respiratory system and impair exercise performance compared to normobaria. At... (Review)
Review
Performing at high altitude and scuba diving impose functional limitations to the respiratory system and impair exercise performance compared to normobaria. At altitude, the partial pressure of oxygen is reduced, which decreases arterial oxygen saturation and exercise performance. Falling arterial oxygen saturation results in hyperventilation and increased pulmonary ventilation. Diving poses unique effects on the respiratory system. The work of breathing is increased from marked increased airway resistance, static lung load, and hydrostatic pressure from the water on the thoracic wall. Both altitude and diving increase the work and energy cost of breathing, resulting in respiratory muscle fatigue. Respiratory muscle training (RMT) has been employed to target the deleterious effects on the respiratory system and exercise capacity. Although the literature is sparse, RMT has been reported to decrease the work and energy cost of breathing and improve pulmonary ventilation, respiratory muscle strength, pulmonary function, and exercise capacity. This narrative review summarizes what is currently known about RMT for exercise performance at altitude and in diving, including potential mechanisms and outlines gaps in the literature.
Topics: Airway Resistance; Altitude; Atmospheric Pressure; Breathing Exercises; Diving; Exercise Tolerance; Humans; Hyperventilation; Muscle Fatigue; Oxygen; Partial Pressure; Pulmonary Ventilation; Respiration; Respiratory Muscles
PubMed: 30352652
DOI: 10.3357/AMHP.5138.2018 -
BMC Pediatrics Mar 2022During puberty, changes in body composition due to sex hormones are associated with lung mechanics. However, little is known about the mediation effect of sex...
BACKGROUND
During puberty, changes in body composition due to sex hormones are associated with lung mechanics. However, little is known about the mediation effect of sex differences in body composition during puberty with total airway resistance.
METHODS
We prospectively recruited 620 children (10-12 years old) from the general population and conducted a cross-sectional study. This study assessed pubertal status according to the five Tanner stages using a questionnaire, line drawings, and each subject's blood sex hormone profile. Both the impulse oscillation system for total lung mechanics and multifrequency bioelectrical impedance for body composition analyses were conducted. The effects of puberty on body composition and subsequent total lung resistance were evaluated using mediation analysis.
RESULTS
Among the 503 children enrolled, there were 261 males (51.9%) and 242 females (48.1%). In males, higher testosterone levels corresponded with reduced total lung resistance (β = -0.13, 95% CI = -0.21 to -0.05, p < 0.001), and the proportion of the mediating effect through the muscle-fat ratio was 19% (95% CI = 4 to 59, p = 0.02). In contrast, in females, pubertal status reduced total lung resistance (β = -0.27, 95% CI = -0.58 to -0.05, p = 0.04), however, the proportion of the mediating effect through the body mass index was -51% (95% CI = -244 to -4%, p = 0.04).
CONCLUSION
The muscle-fat ratio in adolescent males had a synergistic effect with testosterone on improving total airway resistance, whereas improvements in lung resistance by pubertal status were partially masked by body mass index in adolescent females. In conclusion, body composition changes during puberty between males and females have differing effects on total airway resistance.
Topics: Adolescent; Airway Resistance; Body Composition; Body Mass Index; Child; Cross-Sectional Studies; Female; Humans; Lung; Male; Puberty; Sex Characteristics; Testosterone
PubMed: 35300646
DOI: 10.1186/s12887-022-03198-1 -
American Journal of Rhinology & Allergy Mar 2021Past studies reported a low correlation between rhinomanometry and computational fluid dynamics (CFD), but the source of the discrepancy was unclear. Low correlation or...
BACKGROUND
Past studies reported a low correlation between rhinomanometry and computational fluid dynamics (CFD), but the source of the discrepancy was unclear. Low correlation or lack of correlation has also been reported between subjective and objective measures of nasal patency.
OBJECTIVE
This study investigates (1) the correlation and agreement between nasal resistance derived from CFD (R) and rhinomanometry (R), and (2) the correlation between objective and subjective measures of nasal patency.
METHODS
Twenty-five patients with nasal obstruction underwent anterior rhinomanometry before and after mucosal decongestion with oxymetazoline. Subjective nasal patency was assessed with a 0-10 visual analog scale (VAS). CFD simulations were performed based on computed tomography scans obtained after mucosal decongestion. To validate the CFD methods, nasal resistance was measured (R) by performing pressure-flow experiments in anatomically accurate plastic nasal replicas from 6 individuals.
RESULTS
Mucosal decongestion was associated with a reduction in bilateral nasal resistance (0.34 ± 0.23 Pa.s/ml to 0.19 ± 0.24 Pa.s/ml, p = 0.003) and improved sensation of nasal airflow (bilateral VAS decreased from 5.2 ± 1.9 to 2.6 ± 1.9, p < 0.001). A statistically significant correlation was found between VAS in the most obstructed cavity and unilateral airflow before and after mucosal decongestion (r = -0.42, p = 0.003). Excellent correlation was found between R and R (r = 0.96, p < 0.001) with good agreement between the numerical and values (R/R = 0.93 ± 0.08). A weak correlation was found between R and R (r = 0.41, p = 0.003) with CFD underpredicting nasal resistance derived from rhinomanometry (R/R = 0.65 ± 0.63). A stronger correlation was found when unilateral airflow at a pressure drop of 75 Pa was used to compare CFD with rhinomanometry (r = 0.76, p < 0.001).
CONCLUSION
CFD and rhinomanometry are moderately correlated, but CFD underpredicts nasal resistance measured due in part to the assumption of rigid nasal walls. Our results confirm previous reports that subjective nasal patency correlates better with unilateral than with bilateral measurements and in the context of an intervention.
Topics: Airway Resistance; Humans; Hydrodynamics; Nasal Obstruction; Nose; Rhinomanometry; Visual Analog Scale
PubMed: 32806938
DOI: 10.1177/1945892420950157 -
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