scholarly journals Ventilatory response to CO2 with Read's rebreathing method in normal infants

2020 ◽  
Author(s):  
Yosuke Yamada ◽  
Henmi Nobuhide ◽  
Hisaya Hasegawa ◽  
Shio Tsuruta ◽  
Yusuke Suganami ◽  
...  
Keyword(s):  
Body Weight ◽  
Steady State ◽  
Ventilatory Response ◽  
Minute Volume ◽  
Respiratory Center ◽  
Steady State Method ◽  
Examination Time ◽  
Rebreathing Method ◽  
Ventilatory Response To Co2 ◽  
Birth Body Weight

Background Methods of evaluating the ventilatory response to CO2 (VRCO2) of the respiratory center include the steady-state and the rebreathing method. Although the rebreathing method can evaluate the respiratory center more in detail, the steady-state method has been mainly performed in infants. The aim of this study was to investigate whether we could perform the VRCO2 with the rebreathing method in normal infants. Methods The subjects were 80 normal infants. The gestational age was 39.9（39.3-40.3）weeks, and the birth body weight was 3,142 (2,851-3,451) grams. We performed the VRCO2 with Read’s rebreathing method, measuring the increase in minute volume (MV) in response to the increase in EtCO2 by rebreathing a closed circuit. The value of VRCO2 was calculated as follow: VRCO2 (mL/min/mmHg/kg) = ΔMV / ΔEtCO2 / Body weight. Results We performed the examination without adverse events. The age in days at examination was 3 (2-4), and the examination time was 150±38 seconds. The maximum EtCO2 was 51.1 (50.5-51.9) mmHg. The value of VRCO2 was 34.6 (29.3-42.8). Tidal volume had a greater effect on the increase in MV than respiratory rate (5.4 to 14.3 mL/kg, 44.1 to 55.9 /min, respectively). Conclusion This study suggests that the rebreathing method can evaluate the ventilatory response to high blood CO2 in a short examination time. We conclude that the rebreathing method is useful even in infants. In the future, we plan to measure the VRCO2 of preterm infants, and evaluate the respiratory center of infants in more detail.

Sleep and maturation of eucapnic ventilation and CO2 sensitivity in the premature primate

1980 ◽  
Vol 48 (2) ◽  
pp. 347-354 ◽  
Author(s):  
R. D. Guthrie ◽  
T. A. Standaert ◽  
W. A. Hodson ◽  
D. E. Woodrum
Keyword(s):  
Body Weight ◽  
Steady State ◽  
Duty Cycle ◽  
Nrem Sleep ◽  
Minute Volume ◽  
Macaca Nemestrina ◽  
Sleep State ◽  
Postnatal Maturation ◽  
Awake State ◽  
Co2 Sensitivity

The effects of sleep state and postnatal maturation on steady-state CO2 sensitivity, "inspiratory drive" (VT/TI), and the inspiratory "duty cycle" (TI/Ttot) were examined in nine unanesthetized premature Macaca nemestrina in the first 3 wk of life. Minute volume (VE) in room air was less in NREM sleep than in the awake state but there were no differences in VE, VT/TI, or TI/Ttot between REM and NREM sleep. VE and VT/TI corrected for body weight increased in REM and NREM sleep with postnatal maturation whereas TI/Ttot did not vary. Concomitant with this increase in room air VE and VT/TI, an increase in CO2 sensitivity (delta V/delta Paco2) with postnatal maturation was documented in NREM sleep. CO2 sensitivity was similar between REM and NREM states at each postnatal age. The increase in VE following inhalation of 2-5% CO2 was mediated by an increase in VT/TI, whereas TI/Ttot remained constant. The differences in the effect of sleep on CO2 sensitivity between neonates and adults are discussed and possible mechanisms for the observed developmental increase in CO2 sensitivity are proposed.

scholarly journals Reproducibility of hypercapnic ventilatory response measurements with steady-state and rebreathing methods

2018 ◽  
Vol 4 (1) ◽  
pp. 00141-2017
Author(s):  
Denise C. Mannée ◽  
Timon M. Fabius ◽  
Michiel Wagenaar ◽  
Michiel M.M. Eijsvogel ◽  
Frans H.C. de Jongh
Keyword(s):  
Carbon Dioxide ◽  
Steady State ◽  
Rating Scales ◽  
Ventilatory Response ◽  
Intraclass Correlation ◽  
Carbon Dioxide Tension ◽  
Secondary Outcome ◽  
Hypercapnic Ventilatory Response ◽  
Steady State Method ◽  
End Tidal

In this study, the hypercapnic ventilatory response (HCVR) was measured, defined as the ventilation response to carbon dioxide tension (PCO2). We investigated which method, rebreathing or steady-state, is most suitable for measurement of the HCVR in healthy subjects, primarily based on reproducibility. Secondary outcome parameters were subject experience and duration.20 healthy adults performed a rebreathing and steady-state HCVR measurement on two separate days. Subject experience was assessed using numeric rating scales (NRS). The intraclass correlation coefficient (ICCs) of the sensitivity to carbon dioxide above the ventilatory recruitment threshold and the projected apnoea threshold were calculated to determine the reproducibility of both methods.The ICCs of sensitivity were 0.89 (rebreathing) and 0.56 (steady-state). The ICCs of the projected apnoea threshold were 0.84 (rebreathing) and 0.25 (steady-state). The steady-state measurement was preferred by 16 out of 20 subjects; the differences in NRS scores were small.The hypercapnic ventilatory response measured using the rebreathing setup provided reproducible results, while the steady-state method did not. This may be explained by high variability in end-tidal PCO2. Differences in subject experience between the methods are small.

Adaptations to diving in the harbor seal— gas exchange and ventilatory response to CO2

1963 ◽  
Vol 205 (6) ◽  
pp. 1175-1177 ◽  
Author(s):  
Eugene D. Robin ◽  
H. Victor Murdaugh ◽  
William Pyron ◽  
Edgar Weiss ◽  
Peter Soteres
Keyword(s):  
Gas Exchange ◽  
Ventilatory Response ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Pulmonary Gas Exchange ◽  
Respiratory Center ◽  
Harbor Seals ◽  
Response Curves ◽  
Ventilatory Response To Co2

Pulmonary gas exchange and the ventilatory response to CO2 were measured in six female harbor seals, Phoca vitulina. Mean Paco2 (48 ± 6 mm Hg) is higher in the seal and mean Pao2 (88 ± 9 mm Hg) is lower than the corresponding value in man. The seal shows a depressed ventilatory response to CO2 both in terms of slope and intercept of CO2 response curves. The depressed respiratory center sensitivity to CO2 presumably is an adaptative mechanism permitting prolonged diving in this species.

The role of prostaglandins in the realization of respiratory effects of TNF-α in case of hypoxia

2021 ◽  
Author(s):  
G.А. Danilova ◽  
A.A. Klinnikova ◽  
N.P. Aleksandrova
Keyword(s):  
Ventilatory Response ◽  
Minute Volume ◽  
Respiratory Effects ◽  
Cox Inhibitor ◽  
Tnf Α ◽  
Before And After ◽  
Factor Α ◽  
And Control ◽  
Rebreathing Method

At the present time very little is known about interactions between systemic inflammation and control of respiration. The aim of this study was to compare the respiratory effects of the main inflammatory cytokine TNF - α before and after pretreatment with diclofenac, a nonspecific cyclooxygenase (COX) inhibitor. In experiments on anesthetized, tracheostomized rats, pneumotachometry method was used to measure peak airflow and respiratory rate. The ventilatory response to hypoxia was investigated by the rebreathing method. It is shown that an increase in the systemic level of TNF – α causes a significant increase in the minute volume of respiration, tidal volume, the average speed of the inspiratory flow. In contrast the slope of the hypoxic ventilatory response decreased after administration of TNF-α. Diclofenac pretreatment eliminated these respiratory effects of TNF - α. The data indicate that the ability of TNF - α to enhance basal ventilation and to reduce the ventilatory hypoxic response is mediated by the cyclooxygenase pathway. Key words: tumor necrosis factor – α, hypoxia, prostaglandins, peripheral chemoreception, respiration.

Effects of O2 on the ventilatory response to CO2 in preterm infants

1975 ◽  
Vol 39 (6) ◽  
pp. 896-899 ◽  
Author(s):  
H. Rigatto ◽  
R. De La Torre Verduzco ◽  
D. B. Gates
Keyword(s):  
Preterm Infants ◽  
Gestational Age ◽  
Ventilatory Response ◽  
Respiratory Center ◽  
Response Curves ◽  
Co2 Response ◽  
O2 Concentration ◽  
The Mean ◽  
Ventilatory Response To Co2

To measure the effects of O2 on the ventilatory response to CO2 in preterm infants, we studied eight babies (birth wt 1–2 kg; gestational age 32–36 wk) 10 times during the first 11 days of life. After breathing 21% O2 for 3 min, they were given 15%, 21%, 40%, or 100% O2 for 4 min and then 2% CO2 plus the various concentrations of O2 for 4 min each. The mean slopes of the CO2 response curves were 0.013, 0.027, 0.034, and 0.056 1/(min-kg-mmHg PACO2) with 15%, 21%, 40%, and 100% inspired O2, respectively. Thus, the more hypoxic the infant, the flatter was the response to CO2. These findings suggest that in preterm infants 1) the response to inhaled CO2 is the reverse of that seen in adult man where the higher the inspired O2 concentration, the flatter the response, and 2) the respiratory center is depressed during hypoxia.

Ventilatory response of the sleeping newborn to CO2 during normoxic rebreathing

1991 ◽  
Vol 71 (1) ◽  
pp. 168-174 ◽  
Author(s):  
G. Cohen ◽  
C. Xu ◽  
D. Henderson-Smart
Keyword(s):  
Rem Sleep ◽  
Ventilatory Response ◽  
Relative Magnitude ◽  
Quiet Sleep ◽  
Volume Response ◽  
The Mean ◽  
Arterial O2 Saturation ◽  
Arterial Po2 ◽  
Rebreathing Method ◽  
Ventilatory Response To Co2

The ventilatory response of the newborn to CO2 was studied using a rebreathing method that minimized changes in arterial PO2 during the test. The aim was to study the variability of the ventilatory response to CO2 and take this into account to assess the relative magnitude of the response to CO2 during rapid-eye-movement (REM) sleep and quiet sleep (QS). Five full-term babies aged 4–6 days were given 5% CO2 in air to rebreathe for 1.5–3 min. O2 was added to the rebreathing circuit to maintain arterial O2 saturation and transcutaneous PO2 (Ptco2) at prerebreathing levels. Tests were repeated four to five times in REM sleep and QS. Mean Ptco2 levels varied between individuals but were similar during REM sleep and QS tests for each subject. The mean coefficient of variability of the ventilatory response was 35% (range 15–77%) during QS and 120% (range 32–220%) during REM sleep. PtcO2 fluctuations during tests [6.0 +/- 3.0 (SD) Torr, range 1–13 Torr] were not correlated with ventilatory response. Overall the ventilatory response was significantly lower in REM sleep than in QS (12.2 +/- 3.0 vs. 38.7 +/- 3.0 ml.min-1.Torr-1.kg-1, P less than 0.001; 2-way analysis of variance) due to a small (nonsignificant) fall in the tidal volume response and a significant fall in breathing rate. In 12 REM sleep tests there was no significant ventilatory response; mean inspiratory flow increased significantly during 8 of these 12 tests. We conclude that there is a significant decrease in the ventilatory response of the newborn to CO2 rebreathing during REM sleep compared with QS.

Awake baboon's ventilatory response to venous and inhaled CO2 loading

1975 ◽  
Vol 39 (3) ◽  
pp. 417-422 ◽  
Author(s):  
S. M. Lewis
Keyword(s):  
Steady State ◽  
Tidal Volume ◽  
Ventilatory Response ◽  
Venous Blood ◽  
Minute Volume ◽  
Arteriovenous Shunt ◽  
Arterial Pco2 ◽  
Ventilatory Responses ◽  
End Tidal ◽  
Change In Mean

Steady-state ventilatory responses to CO2 in trained awake baboons were studied to determine the response to a venous CO2 load. CO2 was loaded either directly into the venous blood through an arteriovenous shunt or by addition to the inhaled air. The two modes of loading were adjusted to produce the same increase in minute volume. Minute volume, tidal volume respiratory frequency, end-tidal PCO2, PaCO2, and pHa were measured. PaCO2 and PETCO2 increased the same amount during the two modes of CO2 loading; thus, the response to changes in arterial PCO2, deltaVE/deltaPaCO2, was the same. I conclude that the ventilatory response to venous CO2 loading occurs only through the change in mean arterial PCO2 and thus it is unlikely that there are any important venous CO2 receptors.

Ventilatory response to inspired carbon dioxide in infants and adults

1963 ◽  
Vol 18 (5) ◽  
pp. 895-903 ◽  
Author(s):  
Mary Ellen Avery ◽  
Victor Chernick ◽  
Robert E. Dutton ◽  
Solbert Permutt
Keyword(s):  
Body Weight ◽  
Ventilatory Response ◽  
Newborn Infants ◽  
Response Curves ◽  
Steady State Responses ◽  
Buffer Base ◽  
Chemical Stimuli ◽  
The Individual ◽  
State Responses ◽  
Rebreathing Method

A rebreathing method was used to study the increase in ventilation with an increase in PaCOCO2 in newborn infants and adults. The response curve of infants was shifted to the left of that of adults, which is consistent with their lower initial PaCOCO2 and buffer base, and greater metabolism per kilogram of body weight. The rebreathing response curves of infants were also to the left of steady-state responses reported by others. It is postulated that nonchemical stimuli caused higher ventilation throughout the entire range of the CO2 response curves in the infants studied by rebreathing without altering the sensitivity to increases in Pco2. The change in ventilation per kilogram versus the change in PaCOCO2, the slopes of the CO2 response curves, were nearly the same in infants and adults studied by either method. This finding, when the comparison is made on the basis of body weight, suggests the sensitivity of the regulatory apparatus does not change with age, and the output of the effector apparatus, lungs and chest wall, is related to the mass of the individual. CO2 response curves; nonchemical stimuli; chemical stimuli; respiration Submitted on February 19, 1963

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