Methods for identifying respiratory oscillations disclose altitude effects

Brusil, P. J.; Waggener, T. B.; Kronauer, Richard E.; Gulesian, P.

doi:10.1152/jappl.1980.48.3.545

Cited by 37 publications

(29 citation statements)

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“…Brusil and coworkers (8) stated that a breath number time scale is appropriate unless breathing patterns display an extraordinarily large variation in total respiratory cycle time (Ttot). In their study of 16 healthy subjects, the coefficient of variation for Ttot was 20.2 ± 8.6% (mean ± standard deviation) (8). This value is remarkably similar to the value in our 33 subjects (Table I) although our "clamped" data sets show less variability.…”

Section: Experimental Protocolmentioning

confidence: 99%

“…This value is remarkably similar to the value in our 33 subjects (Table I) although our "clamped" data sets show less variability. In their series, Brusil and coworkers (8) calculated that over 70% of the observed variability was uncorrelated from breath to breath. We found a similar fraction of uncorrelated variational activity.…”

Section: Experimental Protocolmentioning

confidence: 99%

“…This quantifies the relativestrength of"shortterm memory" for each breath component (6,7). We also performed cross-correlation analysis, a technique similar to autocorrelation, to determine the relationships betweenany two breath components in neighboring breaths (8,9). Some investigators (10, 11) have observed a significant relationship between TI of one breath and expiratory time (TE) of the adjoining breath in anesthetized animals.…”

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confidence: 99%

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Interrelationship of breath components in neighboring breaths of normal eupneic subjects.

Tobin¹,

Yang²,

Jubran³

et al. 1995

Am J Respir Crit Care Med

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To determine the fraction of variational activity that is correlated on a breath-to-breath basis from uncorrelated random fluctuations, we performed autocorrelation analysis in 33 normal subjects during resting breathing. A calibrated inductive plethysmograph was used to nonobtrusively record 700 breaths in each subject. The group mean autocorrelation coefficients at a lag of 1 breath for each of the three primary breath components, tidal volume (VT), inspiratory time (TI), and expiratory time (TE), were significantly different from zero (p < 0.001). The autocorrelation coefficients for VT, 0.295 +/- 0.148 (SD), and TE, 0.259 +/- 0.121, were greater than that for TI, 0.201 +/- 0.135 (p < 0.001 and p < 0.01, respectively). The autocorrelation coefficients for each breath component remained significant for approximately 3 consecutive breaths (p < 0.001), indicating the presence of "short-term memory." Cross-correlation analysis revealed significant interrelationships (p < 0.001) for all component irrespective of which component was leading or following, with the exception of the pairing of VT in the leading breath and TI in the subsequent breath. In conclusion, in resting healthy subjects breath components display considerable breath-to-breath variability that is not completely random in nature, but which, instead, has a significant fraction of structured correlated variational activity.

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Section: Experimental Protocolmentioning

confidence: 99%

Section: Experimental Protocolmentioning

confidence: 99%

mentioning

confidence: 99%

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Interrelationship of breath components in neighboring breaths of normal eupneic subjects.

Tobin¹,

Yang²,

Jubran³

et al. 1995

Am J Respir Crit Care Med

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“…Brusil et al (1980) reported that 25 % ofhis sojourners at 3050 m altitude showed 'reinforcing oscillations' during which expired breath volume (VE) and TTOT oscillated out of phase and contributed to increased ventilatory fluctuations. Thus, although hypoxia in the presence of hypocapnic alkalosis may increase variability during wakefulness, it appears that the state of the higher C.N.S.…”

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confidence: 99%

Mechanisms of hypoxia‐induced periodic breathing during sleep in humans.

Berssenbrugge¹,

Dempsey²,

Iber³

et al. 1983

The Journal of Physiology

248

181

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SUMMARY1. Ventilation was studied during wakefulness and sleep in six healthy humans in normoxia (mean barometric pressure (PB) = 740 torr), and in hypobaric hypoxia (AB = 455 torr).2. Hypoxia caused hyperventilation and hypocapnic alkalosis (APpao2 =c-7 torr)during wakefulness and in all sleep states. 3. Periodic breathing was the predominant pattern of breathing in all stages of non-rapid eye movement (non-r.e.m.) sleep in hypoxia, but was rarely observed during wakefulness or r.e.m. sleep.4. Periodic breathing was composed of repetitive oscillations of reproducible cycle length characterized by clusters of breaths with augmented inspiratory effort (VT/TI) and highly variable distribution of breath-to-breath minute ventilation (VE) and tidal volume (VT), which alternated regularly with prolongations of the expiratory pause of the last breath of each cluster (apnea duration = 5-18 see). 5. Hypoxia-induced periodic breathing was eliminated by: (a) acute restoration of normoxia coincident with a 3-6 torr increase in PaIc2; and (b) augmented F1,c2(at constant arterial oxygen saturation) which rapidly and reversibly eliminated apneas and stabilized breathing pattern with a < 2 torr increase in Paco2. If hypocapnia was prevented (by augmented F1,co,) during acute induction of hypoxia in non-r.e.m. sleep, periodic breathing was also prevented. 6. We propose that the genesis of hypoxia-induced periodic breathing requires the combination of hypoxia and hypocapnia. Periodicity results from oscillations in CO2 about a C02-apnea threshold whose functional expression is critically linked to sleep state.

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“…Además, se ha encontrado que la ubicación geográfica, la nutrición y la exposición ambiental influyen sobre la función pulmonar (4,(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21).…”

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Valores de referencia para parámetros de espirometría en la población adulta residente en Bogotá, D. C., Colombia

Rojas

Dennis

2010

biomedica

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Nombre de la institución donde se llevó a cabo el trabajo:Departamento de Epidemiología Clínica y Bioestadística, Facultad de Medicina, Pontificia Universidad Javeriana, Bogotá, D.C., ColombiaIntroducción. Los valores de referencia para parámetros de la función pulmonar aplicables a otras poblaciones, han mostrado ser poco válidos en la interpretación de las pruebas de función pulmonar en la población adulta residente en Bogotá. Objetivo. Identificar cuál de cuatro modelos de predicción generados en poblaciones con características étnicas similares a la población colombiana, es el más adecuado para utilizar en adultos de Bogotá. Materiales y métodos. Se reclutaron 534 sujetos de ambos sexos entre los 18 y los 65 años de edad, no fumadores, libres de alteraciones pulmonares, trabajadores de tres empresas privadas y residentes en Bogotá por más de cinco años. La función pulmonar se midió por curva de flujo volumen. Se estimaron las diferencias observadas entre valores predichos y observados, y se calcularon los límites por el método de Bland y Altman. Se aceptaron como válidos los modelos que presentaron un error de predicción promedio máximo de 5% del valor observado en cada parámetro. Resultados. Demostraron ser válidos en esta población los modelos: Crapo para capacidad vital forzada (CVF) en hombres; Pérez-Padilla, para CVF en mujeres y para la relación con el volumen espiratorio forzado en el primer segundo (VEF 1 /CVF) en ambos grupos y los de Hankinson para mexicano-americanos para todos los parámetros en ambos sexos. Conclusiones. Los modelos de Hankinson demostraron ser los más adecuados para predecir todos los parámetros de la espirometría; sin embargo, dejan un porcentaje de mala clasificación promedio de 7%. Se requiere generar modelos propios con mayor precisión pronóstica en la población de Bogotá.Palabras clave: estudios de validación, valores de referencia, pruebas de función respiratoria, modelos lineales, adulto, altitud. Reference values for respiratory parameters in the adult population of Bogotá, D.C., ColombiaIntroduction. Reference values for pulmonary function parameters, generally applicable to most populations, have shown little validity in the correct interpretation of pulmonary function tests when applied to the adult population in Bogotá. Objective. To identify which of four prediction models generated for use in populations of a similar ethnic background to that found in Colombia is the most accurate for use in adults in Bogotá. Materials and methods. 534 subjects (male and female) between 18 and 65 years of age were recruited from a pool of workers employed by three private Bogotá companies. All subjects had resided in Bogotá for at least five years before the initiation of the study. Smokers and those with altered pulmonary function were excluded. Pulmonary function parameters were measured by flow volume curve. The results were analyzed (specifically, the difference between predicted and observed values) and the limits were calculated using the Bland & Altman method. A maximum aver...

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Methods for identifying respiratory oscillations disclose altitude effects

Cited by 37 publications

References 0 publications

Interrelationship of breath components in neighboring breaths of normal eupneic subjects.

Interrelationship of breath components in neighboring breaths of normal eupneic subjects.

Mechanisms of hypoxia‐induced periodic breathing during sleep in humans.

Valores de referencia para parámetros de espirometría en la población adulta residente en Bogotá, D. C., Colombia

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