scholarly journals Ventilatory response to CO 2 with Read's rebreathing method in normal infants

2021 ◽  
Author(s):  
Yosuke Yamada ◽  
Nobuhide Henmi ◽  
Hisaya Hasegawa ◽  
Shio Tsuruta ◽  
Satoko Tokumasu ◽  
...  
Keyword(s):  
Ventilatory Response ◽  
Rebreathing Method

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.

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.

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.

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

Cerebellar modulation of ventilatory response to progressive hypercapnia

1994 ◽  
Vol 77 (3) ◽  
pp. 1073-1080 ◽  
Author(s):  
F. Xu ◽  
J. Owen ◽  
D. T. Frazier
Keyword(s):  
Ventilatory Response ◽  
Minute Ventilation ◽  
Vagus Nerves ◽  
Intact Control ◽  
Ventilatory Responses ◽  
Bilateral Vagotomy ◽  
End Tidal ◽  
Spontaneously Breathing ◽  
Rebreathing Method ◽  
Respiratory Variables

The cerebellar contribution to the ventilatory response to progressive hypercapnia was examined in 18 anesthetized tracheotomized spontaneously breathing cats. The absolute values for minute ventilation (VE), tidal volume (VT), respiratory frequency (f), inspiratory duty cycle (TI/TT), and mean inspiratory flow (VT/TI) were measured. Progressive hypercapnia [35–65 Torr end-tidal PCO2 (PETCO2)] was induced using the rebreathing method. The respiratory variables at each level of PETCO2 and the slopes of ventilatory (VT and f) responses to hypercapnia were compared across the intact, decerebellate, and decerebellate-vagotomized preparations. In 12 cats, decerebellation preceded vagotomy, and in 6 cats the order of the surgical procedures was reversed. The results show that, compared with intact control, decerebellation had little effect on respiratory variables when PETCO2 was 30–35 Torr. However, during a hypercapneic challenge (40–65 Torr PETCO2), VE and the slope of the VE response were significantly reduced. Bilateral vagotomy increased VT and decreased f but failed to alter the ventilatory response in the PETCO2 range of 35–55 Torr. However, combination of decerebellation and vagotomy, regardless of the surgical order, severely blunted VE (35–65 Torr PETCO2) and the slopes of VE, VT and f responses. When decerebellation followed vagotomy, significant decreases in VT (absolute values and slopes) were noted with little further alteration in f response. We conclude that the cerebellum and its interaction with the vagus nerves play a facilitatory or disinhibitory role in the ventilatory responses to hypercapnia.

Response to hypercapnia and exercise hyperpnea in graded anesthesia

1984 ◽  
Vol 57 (6) ◽  
pp. 1796-1802 ◽  
Author(s):  
T. Chonan ◽  
Y. Kikuchi ◽  
W. Hida ◽  
C. Shindoh ◽  
H. Inoue ◽  
...  
Keyword(s):  
Steady State ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Exercise Hyperpnea ◽  
Sciatic Nerves ◽  
End Tidal ◽  
Response To Exercise ◽  
The Relationship ◽  
End Tidal Co2 ◽  
Rebreathing Method

We examined the relationship between response to hypercapnia and ventilatory response to exercise under graded anesthesia in eight dogs. The response to hypercapnia was measured by the CO2 rebreathing method under three grades of chloralose-urethan anesthesia. The degrees of response to hypercapnia (delta VE/delta PETCO2, 1 X min-1 X Torr-1) in light (L), moderate (M), and deep (D) anesthesia were 0.40 +/- 0.05 (mean +/- SE), 0.24 +/- 0.03, and 0.10 +/- 0.02, respectively, and were significantly different from each other. Under each grade of anesthesia, exercise was performed by electrically stimulating the bilateral femoral and sciatic nerves for 4 min. The time to reach 63% of full response of the increase in ventilation (tauVE) after beginning of exercise was 28.3 +/- 1.5, 38.1 +/- 5.2, and 56.0 +/- 6.1 s in L, M, and D, respectively. During steady-state exercise, minute ventilation (VE) in L, M, and D significantly increased to 6.17 +/- 0.39, 5.14 +/- 0.30, and 3.41 +/- 0.16 1 X min-1, from resting values of 3.93 +/- 0.34, 2.97 +/- 0.17, and 1.69 +/- 0.14 1 X min-1, respectively, while end-tidal CO2 tension (PETCO2) in L decreased significantly to 34.8 +/- 0.9 from 35.7 +/- 0.9, did not change in M (38.9 +/- 1.1 from 38.9 +/- 0.8), and increased significantly in D to 47.3 +/- 1.9 from 45.1 +/- 1.7 Torr.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventilatory Response to Exercise and to Co2 Rebreathing in Normal Subjects

1972 ◽  
Vol 43 (6) ◽  
pp. 861-867 ◽  
Author(s):  
A. S. Rebuck ◽  
N. L. Jones ◽  
E. J. M. Campbell
Keyword(s):  
Carbon Dioxide ◽  
Ventilatory Response ◽  
Normal Subjects ◽  
O2 Uptake ◽  
Co2 Output ◽  
Exercise Ventilation ◽  
Progressive Exercise ◽  
Response To Exercise ◽  
Rebreathing Method ◽  
Ventilatory Response To Co2

1. Changes in ventilation during progressive exercise were measured in eleven normal subjects. Ventilatory response to carbon dioxide at rest was measured in the same subjects using a rebreathing method. 2. The range of ventilatory response to exercise was 16·6–32·0 litres min−1 (litres CO2 min−1)−1 (mean 22·7; SD 5·35); response to O2 uptake was 17·0–43·9 litres min−1 (litres O2 min−1)−1 (mean 29·02; SD 9·07). Ventilatory response to CO2 (Sco2) ranged from 0·81 to 3·22 litre min−1 mmHg−1 (mean 1·87; SD 0·62). 3. There was a highly significant (P < 0·001) correlation between the changes in response to increasing CO2 output or O2 uptake, and Sco2. 4. The results are compatible with the suggestion that ventilation during exercise in normal subjects is directly related to their chemosensitivity to CO2, those having the highest sensitivity showing the greatest exercise ventilation.

The Ventilatory Response to CO2 of Patients with Diffuse Pulmonary Infiltrations or Fibrosis

1972 ◽  
Vol 43 (1) ◽  
pp. 55-69 ◽  
Author(s):  
J. M. S. Patton ◽  
S. Freedman
Keyword(s):  
Ventilatory Response ◽  
Normal Subjects ◽  
Work Rate ◽  
Mechanical Work ◽  
Respiratory Response ◽  
Co2 Sensitivity ◽  
Venous Pco2 ◽  
Pulmonary Infiltration ◽  
Rebreathing Method ◽  
Ventilatory Response To Co2

1. We have used the rebreathing method to examine the respiratory response to CO2 in five normal subjects and twelve patients with diffuse pulmonary infiltration or fibrosis. The response to CO2 was measured in terms of both ventilation and mechanical work rate. 2. The response to CO2 was, on average, reduced in the patients compared with the normals but the patients had to perform more mechanical work to achieve a given level of ventilation. 3. Six patients had an abnormally low resting mixed venous Pco2 and four of these also had an abnormally low response to CO2. 4. The pattern of breathing was identical in patients and normals. 5. The results indicate that the reduced ventilatory response represents a true loss of CO2 sensitivity and is not simply due to mechanical limitation; but the paradox in some patients of resting hyperventilation and a low level of CO2 responsiveness is unexplained.

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