Developmental pattern of hypercapnic and hypoxic ventilatory responses from childhood to adulthood

1994 ◽  
Vol 76 (1) ◽  
pp. 314-320 ◽  
Author(s):  
C. L. Marcus ◽  
W. B. Glomb ◽  
D. J. Basinski ◽  
S. L. Davidson ◽  
T. G. Keens
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Body Size ◽  
Respiratory Rate ◽  
Body Surface ◽  
Vital Capacity ◽  
Developmental Pattern ◽  
Ventilatory Responses ◽  
End Tidal ◽  
Arterial O2 Saturation

The developmental pattern of ventilatory responses, through childhood and puberty into adulthood, is not known. Therefore we studied hypercapnic (HCVR) and hypoxic ventilatory responses (HOVR) in 59 subjects (29 males and 30 females) 4–49 yr of age, of whom 35 were children ( < 18 yr old). There was a significant correlation between HCVR and weight (r = 0.33, P < 0.02), vital capacity (r = 0.30, P < 0.05), and body surface area (r = 0.30, P < 0.05) but not height (r = 0.22, NS). There was no correlation between HOVR and any of the correcting factors. To account for disparities in body size, volume-related results were scaled for body weight. The HCVR corrected for weight (HCVR/WT) decreased with age (r = -0.57, P < 0.001). HCVR/WT was significantly higher in children than in adults (0.056 +/- 0.024 vs. 0.032 +/- 0.015 l.kg-1 x min-1. Torr end-tidal PCO2-1, P < 0.001). The (tidal volume/inspiratory duration)/weight, respiratory rate, and heart rate responses to hypercapnia were increased in the children, and the CO2 threshold was lower (36 +/- 5 vs. 40 +/- 6 Torr, P < 0.05). Similarly, the HOVR corrected for weight (HOVR/WT) decreased with age (r = 0.34, P < 0.05), and HOVR/WT was significantly higher in children than in adults (-0.035 +/- 0.017 vs. -0.024 +/- 0.016 l.kg-1 x min-1.% arterial O2 saturation-1, P < 0.02). The respiratory rate and heart rate responses to hypoxia were increased in the children. We conclude that rebreathing HCVR and HOVR are higher during childhood than during adulthood.

Ventilatory Patterns During Hypoxia, Hypercapnia, and Exercise in Adolescents With Mild Scoliosis

PEDIATRICS ◽  
1986 ◽  
Vol 77 (5) ◽  
pp. 692-697
Author(s):  
R. J. Smyth ◽  
K. R. Chapman ◽  
T. A. Wright ◽  
J. S. Crawford ◽  
A. S. Rebuck
Keyword(s):  
Tidal Volume ◽  
Vital Capacity ◽  
Severe Disease ◽  
Pulmonary Mechanics ◽  
Normal Range ◽  
Ventilatory Responses ◽  
Volume Response ◽  
The Mean ◽  
Arterial O2 Saturation ◽  
Maximal Voluntary Ventilation

Adolescents with mild, asymptomatic scoliosis (thoracic curvature &lt;35°) may have little or no impairment of resting lung volumes. Progression to more severe disease may, however, be accompanied by lung restriction, impaired exercise tolerance, and respiratory failure with CO2 retention. We wished to see whether adolescents with mild scoliosis and minimally abnormal resting pulmonary mechanics had impairment of their responses to hypercapnia, hypoxia, and progressive cycle exercise. Forty-four adolescents with idiopathic scoliosis were studied. The mean forced vital capacity (FVC), expressed as a percentage of the predicted value, was 94.3 ± 2.2 (SE). The mean ventilatory response to hypercapnia (2.57 ± 0.24 L/min/mm Hg) was within the normal range but was achieved with a tidal volume response (1.87 ± .17% vital capacity [VC]/mm Hg) that was significantly lower than that previously reported in healthy young adults. Ventilatory responses to exercise were also within the normal range, the mean dyspnea index (VE-max/maximal voluntary ventilation) = 0.92 ± 0.04. However, at a ventilation of 30 L/min, the tidal volume was 0.38 ± 0.01% FVC, which was considerably lower than predicted. The tidal volume response to hypoxia was also abnormally low, the mean response being 0.52 ± 0.059% VC/% decrease in arterial O2 saturation. These findings indicated that, even when scoliosis is asymptomatic and associated with minimal impairment of resting pulmonary function, abnormal patterns of ventilation occur during exercise or in response to chemical stimuli.

Time course of augmentation and depression of hypoxic ventilatory responses at altitude

1994 ◽  
Vol 77 (1) ◽  
pp. 313-316 ◽  
Author(s):  
M. Sato ◽  
J. W. Severinghaus ◽  
P. Bickler
Keyword(s):  
Pulse Oximetry ◽  
Sea Level ◽  
Time Course ◽  
Ventilatory Response ◽  
Barometric Pressure ◽  
Hypoxic Ventilatory Response ◽  
Set Point ◽  
Ventilatory Responses ◽  
End Tidal ◽  
Arterial O2 Saturation

Hypoxic ventilatory response (HVR) and hypoxic ventilatory depression (HVD) were measured in six subjects before, during, and after 12 days at 3,810-m altitude (barometric pressure approximately 488 Torr) with and without 15 min of preoxygenation. HVR was tested by 5-min isocapnic steps to 75% arterial O2 saturation measured by pulse oximetry (Spo2) at an isocapnic PCO2 (P*CO2) chosen to set hyperoxic resting ventilation to 140 ml.kg-1.min-1. Hypercapnic ventilatory response (HCVR, 1.min-1.Torr-1) was tested at ambient and high SPO2 6–8 min after a 6- to 10-Torr step increase of end-tidal PCO2 (PETCO2) above P*CO2. HCVR was independent of preoxygenation and was not significantly increased at altitude (when corrected to delta logPCO2). Preoxygenated HVR rose from -1.13 +/- 0.23 (SE) l.min-1.%SPO2(-1) at sea level to -2.17 +/- 0.13 by altitude day 12, without reaching a plateau, and returned to control after return to sea level for 4 days. Ambient HVR was measured at P*CO2 by step reduction of SPO2 from its ambient value (86–91%) to approximately 75%. Ambient HVR slope was not significantly less, but ventilation at equal levels of SPO2 and PCO2 was lower by 13.3 +/- 2.4 l/min on day 2 (SPO2 = 86.2 +/- 2.3) and by 5.9 +/- 3.5 l/min on day 12 (SPO2 = 91.0 +/- 1.5; P < 0.05). This lower ventilation was estimated (from HCVR) to be equivalent to an elevation of the central chemoreceptor PCO2 set point of 9.2 +/- 2.1 Torr on day 2 and 4.5 +/- 1.3 on day 12.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Assessment of the Functional State of the Cardiovascular System in Adolescents Living in the Southern Aral Sea Region

2021 ◽  
Vol 7 (9) ◽  
pp. 331-340
Author(s):  
K. Rozumbetov ◽  
S. Esemuratova ◽  
S. Nisanova ◽  
I. Nazhimov ◽  
A. Esimbetov ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Weight ◽  
Body Size ◽  
Cardiovascular System ◽  
Environmental Conditions ◽  
Harmful Effect ◽  
Aral Sea ◽  
Excess Body Weight ◽  
Total Body

According to studies conducted in recent years, there is a harmful effect of harmful chemicals in the environment on the cardiovascular system. The level of blood pressure is a very important hemodynamic indicator, the level of which provides primary information about diseases of the cardiovascular system. In this study, the indicators of total body size, blood pressure and heart rate were measured in adolescents living in unfavorable environmental conditions of the Aral Sea region. In adolescents of both sexes, body weight deficiency occupied a significant share. In girls and boys, the excess body weight was about 5%. Obesity was not observed in adolescents of both sexes. Hypotension was detected in 17.64% of the females studied by categories of systolic blood pressure, and there were no cases of hypertension among the females. And in males, hypotension of 8.70% and hypertension of 4.35% were observed. According to the categories of diastolic blood pressure, hypotension of 2.95% and hypertension of 8.82% were detected in females, hypotension of 8.69% and hypertension of 8.70% in males.

scholarly journals Physiological differences between twin and single-born lambs and kids during the first month of life

2016 ◽  
Vol 59 (2) ◽  
pp. 201-207 ◽  
Author(s):  
Francesco Fazio ◽  
Francesca Arfuso ◽  
Elisabetta Giudice ◽  
Claudia Giannetto ◽  
Giuseppe Piccione
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Respiratory Rate ◽  
Analysis Of Variance ◽  
Rectal Temperature ◽  
Repeated Measures ◽  
Repeated Measures Analysis ◽  
Postnatal Adaptation ◽  
Physiological Differences

Abstract. The effects of time after birth and of twinning on rectal temperature (RT), heart rate (HR), respiratory rate (RR) and body weight (BW) values were evaluated in five singleton Comisana lambs (three males and two females), five singleton Maltese Kids (three males and two females), four couples of twin Comisana lambs (four males and four females) and four couples of twin Maltese kids (four males and four females) during the first month of life. For all kids and lambs, RT, HR, RR and BW were recorded after 1 and 24 h from birth and every 2 days until the 30th day of life. The application of two-way repeated measures analysis of variance (ANOVA) showed a statistically significant effect of time (P < 0.0001) on RT, HR, RR and BW values in all lambs and kids during the first month of life. Any significant effect of twinning (P > 0.05) on all studied parameters was found in lambs, whereas statistically significant differences in BW, RT and HR values (P < 0.01) were found between twin and singleton kids throughout the first month of life. The results obtained in this study make a contribution to the knowledge of homeostatic, cardiorespiratory and thermoregulatory adaptations occurring in singleton lambs and kids and in twin lambs and kids during the first 30 days of life. Our findings indicate that the BW, RT, HR and RR values, whose homeostasis is still evolving in newborn, should be interpreted dynamically as a function of the period of postnatal adaptation and also of twinning.

Ventilatory responses to cardiac output changes in patients with pacemakers

1981 ◽  
Vol 51 (5) ◽  
pp. 1103-1107 ◽  
Author(s):  
P. W. Jones ◽  
W. French ◽  
M. L. Weissman ◽  
K. Wasserman
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Uptake ◽  
Blood Gas ◽  
Cardiac Pacemakers ◽  
Ventilatory Responses ◽  
Mean Delay ◽  
Arterial Blood ◽  
End Tidal

Cardiac output changes were induced by step changes of heart rate (HR) in six patients with cardiac pacemakers during monitoring of ventilation and gas exchange, breath-by-breath. Mean low HR was 48 beats/min; mean high HR was 82 beats/min. The change of oxygen uptake immediately after the HR change was used as an index of altered cardiac output. After HR increase, oxygen uptake (V02) rose by 34 +/- 20% (SD), and after HR decrease, Vo2 fell by 24 +/- 11%. There was no change in arterial blood pressure. After HR increase, ventilation increased, after a mean delay of 19 +/- 4 s; after HR reduction, ventilation fell, after a mean delay of 29 +/- 7 s. In the period between HR increase and the resulting increase in ventilation, end-tidal PCO2 (PETCO2) rose by 2.6 +/- 2.0 Torr, and in the period between HR decreases and the fall in ventilation, PETCO2 dropped by 2.9 +/- 2.2 Torr. The response time and end-tidal gas tension changes implicate the chemoreceptors in the reflex correction of blood gas disturbances that may result from imbalances between cardiac output and ventilation.

Maturational differences in step vs. ramp hypoxic and hypercapnic ventilatory responses

1994 ◽  
Vol 76 (5) ◽  
pp. 1968-1975 ◽  
Author(s):  
D. Gozal ◽  
R. Arens ◽  
K. J. Omlin ◽  
C. L. Marcus ◽  
T. G. Keens
Keyword(s):  
Vital Capacity ◽  
Stimulus Presentation ◽  
Peripheral Chemoreceptors ◽  
Prepubertal Children ◽  
Ventilatory Responses ◽  
End Tidal ◽  
Step Responses

The influence of the speed of stimulus presentation on hypoxic and hypercapnic ventilatory responses (step vs. ramp) is not known. Furthermore, it is unclear whether children and adults respond similarly. We tested ramp ventilatory responses to hypercapnia and hypoxia with use of rebreathing in 8 prepubertal children and 11 adults. We tested step ventilatory responses to hypercapnia with single vital capacity breaths of 15% CO2 in O2 and to hypoxia with five tidal breaths of 100% N2. For children, slopes of step hypercapnic ventilatory responses were always greater than those of ramp responses (0.85 +/- 0.07 vs. 0.71 +/- 0.07 l.min-1.Torr end-tidal PCO2-1; P < 0.0005). Conversely, for adults, step responses were always less than ramp responses (0.88 +/- 0.19 vs. 2.10 +/- 0.29 l.min-1.Torr end-tidal PCO2-1; P < 0.0007). Similarly, for children, the slopes of step hypoxic ventilatory responses were always greater than those of ramp responses (-0.71 +/- 0.09 vs. -0.45 +/- 0.04 l.min-1.Torr O2 saturation-1; P < 0.02), and for adults, step responses were always less than ramp responses (-0.68 +/- 0.14 vs. -1.85 +/- 0.46 l.min-1.Torr O2 saturation-1; P < 0.04). We conclude that ventilatory responses vary depending on step vs. ramp presentation of hypercapnia or hypoxia and that the ratio of these responses is reversed in children compared with adults. We speculate that the responsiveness of peripheral chemoreceptors is increased in children compared with adults and that it may play a role in the mechanisms leading to increased ventilatory responses observed during childhood.

Hypoxic and hypercapnic ventilatory responses in Prader-Willi syndrome

1994 ◽  
Vol 77 (5) ◽  
pp. 2224-2230 ◽  
Author(s):  
R. Arens ◽  
D. Gozal ◽  
K. J. Omlin ◽  
F. R. Livingston ◽  
J. Liu ◽  
...  
Keyword(s):  
Sleep Disordered Breathing ◽  
Control Group ◽  
Prader Willi Syndrome ◽  
Ventilatory Control ◽  
Peripheral Chemoreceptor ◽  
Ventilatory Responses ◽  
Obese Control ◽  
The Mean ◽  
End Tidal ◽  
Arterial O2 Saturation

Abnormalities of ventilatory control may play a significant role in the pathophysiology of sleep-disordered breathing in patients with the Prader-Willi syndrome (PWS). We measured rebreathing hypercapnic and hypoxic ventilatory responses (HCVR and HPVR, respectively) during wakefulness in 8 nonobese PWS (NOB-PWS) and 9 obese PWS (OB-PWS) patients and compared their results with those from 24 healthy nonobese control (NOB-CON) and 10 obese control (OB-CON) subjects. The slope of HCVR was similar in NOB-PWS patients and NOB-CON subjects (NS). However, HCVR was significantly lower in OB-PWS patients than in OB-CON subjects (P < 0.02). In PWS patients, the mean point of origin of the positive slope of HCVR occurred at a significantly higher end-tidal PCO2 than in either control group. During isocapnic hypoxic challenges, six PWS patients had no significant HPVR. In the remainder, mean slopes of HPVR were -0.80 +/- 0.06 l.min-1.%arterial O2 saturation-1 in five NOB-PWS patients and -0.68 +/- 0.15 l.min-1.%arterial O2 saturation-1 in six OB-PWS patients. These responses were significantly decreased compared with those in the control groups (P < 0.006). We conclude that NOB-PWS patients have normal HCVR, which is blunted in OB-PWS patients. Furthermore, isocapnic HPVR is either absent or markedly reduced in PWS patients. The severity of abnormality of the HPVR is independent of the degree of obesity. We postulate that the primary abnormality of ventilatory control in PWS affects peripheral chemoreceptor pathways.

Ventilatory responses of newborn calves to progressive hypoxia in quiet and active sleep

1980 ◽  
Vol 48 (5) ◽  
pp. 892-895 ◽  
Author(s):  
H. E. Jeffery ◽  
D. J. Read
Keyword(s):  
Ventilatory Response ◽  
Active Sleep ◽  
Sleep State ◽  
Quiet Sleep ◽  
Ventilatory Responses ◽  
Progressive Hypoxia ◽  
Newborn Calves ◽  
End Tidal ◽  
Arterial O2 Saturation ◽  
And Behavior

Isocapnic progressive hypoxia was produced by rebreathing 8-10% oxygen in replicate tests during quiet and active sleep, in five full-term calves aged 1-8 days. Airflow through a tightly fitting mask was digitized at 50-ms intervals to calculate breath-by-breath ventilation and rate. Using a cuvette oximeter, arterial O2 saturation (SaO2) was recorded continuously. A mass-spectrometer record of end-tidal PO2 and PCO2 confirmed the mask seal and the constancy of PCO2. Sleep state was characterized by EEG, EOG, neck EMG, and behavior. In quiet sleep the ratio of ventilation to its normoxic control (VR) increased linearly as SaO2 fell; reflex arousal occurred at SaO2 84.9 ± 4.3% (SD) with VR 1.4 ± 0.39 (SD). In contrast, during active sleep, hypoxemia progressed without any ventilatory response to a very low SaO2; a reflex arousal occurred at SaO2 59.2 ±11.0%, often with a ventilatory response developing abruptly just prior to arousal. The slope of the VR/SaO2 regression lines for the overlapping range of SaO2 differed significantly with state in each animal (P < 0.001); the pooled VR values at SaO2 75% were 1.73± 0.15 (SD) and 0.91 ± 0.18 for quiet and active sleep respectively. The depression of the ventilatory response to hypoxia in active sleep differs from previous reports on adult dogs. The basis for this difference needs to be evaluated in relation to species and age, in particular in relation to both the mechanics of breathing and to chemoreceptor reflexes.

scholarly journals The Cardiovascular Effects of Pancuronium in the Dog during Pentobarbitone Anaesthesia

1976 ◽  
Vol 4 (2) ◽  
pp. 135-137 ◽  
Author(s):  
J. M. Gibbs ◽  
A. R. Tait ◽  
M. K. Sykes
Keyword(s):  
Carbon Dioxide ◽  
Heart Rate ◽  
Body Weight ◽  
Cardiac Output ◽  
Muscle Relaxation ◽  
Cardiovascular Effects ◽  
End Tidal Carbon Dioxide ◽  
Pulmonary Arterial ◽  
End Tidal ◽  
Cardiac Output Measurements

The effect of pancuronium on the cardiovascular system of the dog was studied in 12 greyhounds who were anaesthetized with pentobarbitone 30–40 mg/kg body weight. During the study, the animals were artificially ventilated to give an end-tidal carbon dioxide in the range 4·0–4·5 per cent. Duplicate cardiac output measurements were made before and ten minutes after the intravenous administration of pancuronium (0·18 mg/kg). There was a slight (but statistically insignificant) fall in cardiac output. Heart rate, aortic and pulmonary arterial pressures remained substantially unaltered. It is suggested that pancuronium should be used in the dog when muscle relaxation is required during pentobarbitone anaesthesia. In this way cardiovascular changes related to the drugs themselves will be minimized.

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