Mathematical analysis of the time course of alveolar CO<sub>2</sub>

Yamamoto, William S.

doi:10.1152/jappl.1960.15.2.215

Cited by 113 publications

(47 citation statements)

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“…In this experimental run, 4pH and calculated 4Paco 2 increased from 0.0188 and 1.84 Torr in the control (with no bypass, spontaneous respiration) to 0.0193 and 2.80 Torr in the venous C02 loading, respectively. These values were comparable with those obtained with the glass electrode (BAND et al, 1969a;BONDI and VAN LIEW, 1973) and from the mathematical model (YAMAMOTO, 1960). (4pH) synchronizing with the respiratory cycle in a dog weighing 11.2 kg.…”

Section: Resultssupporting

confidence: 87%

Open-loop analysis of Pax(x=CO2) oscillation in the dog.

1984

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Venous C02 loading and/or unloading using an artificial lung was performed on dogs to evaluate whether changes in the rate of carbon dioxide output (V002) can be involved in the control of respiration. As the signal providing J'2 information, small fluctuations in arterial Pco2 (4Paco2) which synchronized with the respiratory cycle were estimated from both the mean Pa002 and the fluctuations in arterial pH (4pH) measured with a catheter tip ISFET (ion sensitive field-effect transistor) pH sensor inserted in the common carotid artery. The open-loop method was used to analyze the effects of various respiratory parameters such as j02, tidal volume, and respiratory frequency on the changes in dpH and 4Paco2. Findings are: (1) 4Paco2 was linearly proportional to VC02 while the correlation between 4pH and VC02 was less linear, (2) magnitude of 4pH was dependent on the changes in tidal volume while 4Pa0O2 was not, (3) both the amplitude and the positive slope of Pa002 oscillation were functions of respiratory frequency. These results suggest the possibility that if Vco2 itself takes part in the control of ventilation, it will be C02 oscillation which links ventilation with Vco2.

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Section: Resultssupporting

confidence: 87%

Open-loop analysis of Pax(x=CO2) oscillation in the dog.

1984

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“…Firstly there could be a very small change in the mean level of the gas tensions or pH, undetected by measurement on arterial blood samples because of the moment-to-moment variation in ventilation and the errors of measurement of pH, blood gases and ventilation. Secondly, the signal could be due to a change in the pattern of the arterial PCO, or pH oscillations in arterial blood (Yamamoto, 1960;Saunders, 1980) or alteration in their temporal relationships to the ventilatory cycle (Cross, Grant, Guz, Jones, Semple & Stidwill, 1979). Both the amplitude and the rate of change of PCO. on the upstroke of the oscillation (or rate of change of pH on the downstroke of the oscillation) are largely determined by 10co, and are therefore potential humoral signals linking ventilation and TC0.…”

Section: Introductionmentioning

confidence: 99%

“…Both the amplitude and the rate of change of PCO. on the upstroke of the oscillation (or rate of change of pH on the downstroke of the oscillation) are largely determined by 10co, and are therefore potential humoral signals linking ventilation and TC0. in exercise (Yamamoto, 1960;Band, McClelland, Phillips, Saunders & Wolff, 1978; Saunders, 1980;Cross, Jones, Leaver, Semple & Stidwill, 1981). The postulated humoral signals enumerated above could only be detected with certainty by a rapidly responding electrode system within the arterial blood.…”

Section: Introductionmentioning

confidence: 99%

The pH oscillations in arterial blood during exercise; a potential signal for the ventilatory response in the dog

Cross¹,

Davey²,

Guz³

et al. 1982

The Journal of Physiology

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SUMMARY1. The effect of electrically induced 'exercise' on the respiratory oscillation of arterial pH was studied in chloralose-anaesthetized dogs with spinal cord transaction at T8/9 (dermatome level T6/7).2. Respiratory oscillations of arterial pH (presumed to be due to oscillations of arterial Pco2) were sensed with a fast-responding electrode in one carotid artery.Breath-by-breath estimates of the maximum rate of change of pH of the downstroke of the pH oscillation (dpH/dtjmax) were obtained by differentiating the pH signal.3. Consistent with the findings of the previous paper (Cross et al. 1982), the ventilatory response to exercise could not be explained on the basis of sensitivity to C02; the A T4/APaco, was significantly greater for 'exercise' than for CO2 inhalation.4. On average, the amplitude of the pH oscillations decreased during 'exercise'.The change in the phase relationship (0) between respiratory and pH cycles, although significant from the second breath onwards, was not thought to be responsible for the increased ventilation V,; the direction of the change was opposite to that previously found to increase VI. 14 and dpH/dtjmax were also linearly related during the on-transient, although the same relationship did not hold true throughout 'exercise'.6. The dpH/dtjmax was related to CO2 production (1rco,) lending support to the prediction that the slope of the downstroke of the pH oscillation is a function of TCo2.7. It was concluded that the dpH/dtimax (dpCO2/dttmax) is a potential humoral signal in 'exercise' and could account totally for the shortening of te. Since there was a late rise in VI (due to an increase in tidal volume VT) in the absence of a change in dpH/dtjmax, it was considered unlikely that the dpH/dtjmax was the only humoral signal present during 'exercise'.

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“…Alternating breath tests seemed most promising in this regard. These have stemmed from the suggestion that periodic variations in blood gas tension are caused by the breathing cycle [10], and from reported variations in peripheral chemoreceptor discharges linked to breathing cycles [11]. Subsequent studies in animals have established: that peripheral chemoreceptors respond to induced changes in arterial carbon dioxide tension (Pa,CO 2 ) and arterial oxygen tension (Pa,O 2 ) [12,13]; that responses to changes in oxygen tension are carotid body dependent [14]; and that exposure to chronic hypoxia may weaken the response [15].…”

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confidence: 99%

Peripheral chemoresponses of infants measured by a minimally invasive method utilizing two-breath alternations in Fl,02

Thomas¹,

Poole²,

McArdle³

et al. 1996

Eur Respir J

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The aim of this study was to develop a minimally invasive and reliable method for measuring peripheral chemoresponsiveness to oxygen in infants, and to establish baseline data from normal infants at 12 weeks of age. Two-breath alternations in fractional inspired oxygen (FI,O 2 ), switching between 0.42 to 0.00 were given for 2 min periods via a face mask (held close to the face but without contact) to 18 healthy infants during quiet sleep. End-tidal oxygen concentrations alternated between 21 and 11%. Instantaneous minute ventilation (V ' 'E) and its components tidal volume (VT), respiratory frequency (fR) inspiratory and expiratory times (tI and tE), inspiratory flow (VT/tI), and inspiratory duty cycle (tI/ttot) were measured by respiratory inductance plethysmography. Two-breath alternations in each of the ventilatory components were matched with the corresponding alternating end-tidal oxygen record and compared with contiguous pre-and post-test data obtained in control periods of air breathing.Alternations in all ventilatory components except f R changed significantly during FI,O 2 alternations; VT 26%, tE -8%, VT/tI 18%, tI/ttot 11% and V ' 'E 28% of baseline values. Within and between infant variances are reported for the individual components of ventilation. Differences among infants were best detected by alternations in V ' 'E; within infant variance 76, between infant variance 171.We conclude that the test described is a safe, reliable and relatively easily applied method of measuring peripheral chemoresponsiveness, which is suitable for clinical application in infancy.

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Mathematical analysis of the time course of alveolar CO₂

Cited by 113 publications

References 0 publications

Open-loop analysis of Pax(x=CO2) oscillation in the dog.

Open-loop analysis of Pax(x=CO2) oscillation in the dog.

The pH oscillations in arterial blood during exercise; a potential signal for the ventilatory response in the dog

Peripheral chemoresponses of infants measured by a minimally invasive method utilizing two-breath alternations in Fl,02

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Mathematical analysis of the time course of alveolar CO2

Cited by 113 publications

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Open-loop analysis of Pax(x=CO2) oscillation in the dog.

Open-loop analysis of Pax(x=CO2) oscillation in the dog.

The pH oscillations in arterial blood during exercise; a potential signal for the ventilatory response in the dog

Peripheral chemoresponses of infants measured by a minimally invasive method utilizing two-breath alternations in Fl,02

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Mathematical analysis of the time course of alveolar CO₂