Chemoreceptor Reflexes in Preterm Infants: I. The Effect of Gestational and Postnatal Age on the Ventilatory Response to Inhalation of 100% and 15% Oxygen

PEDIATRICS ◽  
1975 ◽  
Vol 55 (5) ◽  
pp. 604-613
Author(s):  
Henrique Rigatto ◽  
June P. Brady ◽  
Rafael de la Torre Verduzco
Keyword(s):  
Heart Rate ◽  
Preterm Infant ◽  
Preterm Infants ◽  
Ventilatory Response ◽  
Periodic Breathing ◽  
Postnatal Life ◽  
Low Oxygen ◽  
Peripheral Chemoreceptor ◽  
Peripheral Chemoreceptors ◽  
Oxygen Breathing

We studied 16 "healthy" preterm infants (birthweight, 1,000 to 2,000 gm) 94 times during postnatal life to define the effect of gestational and postnatal age on the ventilatory response to 100% and 15% oxygen. They were given air, then 100% oxygen for two and five minutes respectively (No. = 63) or 21%, 15%, and then 21% oxygen for five minutes each (No. = 31). We measured respiratory minute and tidal volumes, frequency, heart rate, and alveolar Pco2 and Po2. We used the magnitude of the immediate change in ventilation during 100% and 15% oxygen breathing to test peripheral chemoreceptor function. The immediate decrease in ventilation with 100% oxygen and the immediate increase in ventilation with 15% oxygen were statistically similar at different gestational and postnatal ages. The late increase in ventilation (five minutes) with 100% oxygen was also similar at different ages. However, the late decrease in ventilation with 15% oxygen was not present at 18 days of age. These findings suggest that: (1) the peripheral chemoreceptors are active at least from 28 weeks of gestation and are probably not important in triggering periodic breathing or apnea in preterm infants; and (2) the preterm infant matures his response to hypoxia and is able to sustain hyperventilation with low oxygen by 18 days of age.

Effect of baseline oxygenation on the ventilatory response to inhaled 100% oxygen in preterm infants

1995 ◽  
Vol 79 (6) ◽  
pp. 2101-2105 ◽  
Author(s):  
A. Z. Haider ◽  
V. Rehan ◽  
S. Al-Saedi ◽  
R. Alvaro ◽  
K. Kwiatkowski ◽  
...  
Keyword(s):  
Preterm Infants ◽  
Ventilatory Response ◽  
Recovery Period ◽  
Control Period ◽  
Periodic Breathing ◽  
Quiet Sleep ◽  
Peripheral Chemoreceptor ◽  
Lower Baseline ◽  
O2 Concentration ◽  
Flow Through

We tested the hypothesis that the immediate (< 1 min) ventilatory response to 100% O2 in preterm infants, a test of peripheral chemoreceptor activity characterized by a decrease in ventilation due to apnea, is more pronounced at lower baseline O2 concentrations. We studied 12 healthy preterm infants [birth weight 1,425 +/- 103 (SE) g; study weight 1,670 +/- 93 g; gestational age 30 +/- 1 wk; postnatal age 27 +/- 7 days] during quiet sleep. The infants inhaled 15, 21, 25, 30, 35, 40, and 45% O2 for 5 min in a randomized manner (control period), followed by 100% O2 for 2 min, and then the same initial O2 concentration again for 2 min (recovery period). A nose piece and a flow-through system were used to measure ventilation. The immediate decrease in ventilation with 100% O2 was 46% on 15% O2, 24% on 21% O2, 11% on 25% O2, 8% on 30% O2, 12% on 35% O2, and 8% on 40% O2; there was no decrease on 45% O2 (P < 0.01). The corresponding mean duration of apnea was 29 s during 15% O2, 18 s during 21% O2, 8 s during 25% O2, 9 s during 30 and 35% O2, and 3 s during 40% O2; only one infant developed a 5-s apnea during 45% O2 (P < 0.001). The findings suggest that 1) the ventilatory decrease in response to 100% O2 is dependent on the baseline oxygenation, being more pronounced the lower the baseline O2 concentration; and 2) this ventilatory decrease is entirely related to more prolonged apneas observed with lower baseline O2 concentrations. We speculate that the peripheral chemoreceptors, being so active in the small preterm infant with relatively low arterial PO2, are highly susceptible to changes in PO2, and this makes them prone to irregular or periodic breathing, especially during sleep.

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

1976 ◽  
Vol 41 (5) ◽  
pp. 609-611 ◽  
Author(s):  
S. Albersheim ◽  
R. Boychuk ◽  
M. M. Seshia ◽  
D. Cates ◽  
H. Rigatto
Keyword(s):  
Preterm Infants ◽  
Ventilatory Response ◽  
Background Concentrations ◽  
Peripheral Chemoreceptor ◽  
Co2 Response ◽  
Peripheral Chemoreceptors ◽  
Paradoxical Response

We wanted to know wheter the paradoxical response to CO2 under various background concentrations of O2 in preterm infants was mediated at the peripheral chemoreceptors. In five preterm infants we estimated peripheral chemoreceptor activity using the immediate change in ventilation (first 30 s) when 15%, 40%, 60%, or 100% O2 was substituted for 21% O2. Potentiation between O2 and CO2 was assessed by comparing the response with and without 4% CO2. CO2 enhanced the immediate hyperventilation with hypoxia (P less than 0.005) and reduced the immediate hypoventilation with hyperoxia (P less than 0.025 for 40% O2). This effect of CO2 increased from .00% to 15% O2 (P lessthan 0.05). These findings suggest: 1) CO2 interacts with O2 at the peripheral chemoreceptor level, and 2) because this interaction is more pronouncedwith hypoxia, the flatter CO2 response we observed with hypoxia was probably not mediated through the peripheral chemoreceptors and is likely to be central in origin.

PERIODIC BREATHING AND APNEA IN PRETERM INFANTS. I. EVIDENCE FOR HYPOVENTILATION POSSIBLY DUE TO CENTRAL RESPIRATORY DEPRESSION

PEDIATRICS ◽  
1972 ◽  
Vol 50 (2) ◽  
pp. 202-218
Author(s):  
Henrique Rigatto ◽  
June P. Brady
Keyword(s):  
Preterm Infants ◽  
Periodic Breathing ◽  
Significant Shift ◽  
Peripheral Chemoreceptor ◽  
Co2 Response ◽  
Peripheral Chemoreceptors ◽  
Mean Values ◽  
Periodic Groups ◽  
Major Defect ◽  
Alveolar Capillary

We made 84 studies on 20 "healthy" preterm infants during the first 34 days of life to discover whether infants breathing periodically hypoventilate or hyperventilate and whether the major defect is at the central or peripheral chemoreceptors. Six infants breathed periodically (n = 26) and seven regularly (n = 27) at all times; seven infants breathed periodically (n = 15) or regularly (n = 16) in different studies. In these three groups (periodic, regular, and intermediate), we compared respiratory minute volume and frequency, heart rate, alveolar oxygen tension (PAO2) and alveolar carbon dioxide tension (PACO2) and PO2, PCO2 and pH of arterialized capillary blood, alveolar-capillary differences for PO2 and PCO2, peripheral chemoreceptor sensitivity and CO2 responses. We measured ventilation with a nosepiece and a screen flowmeter. The mean values for the intermediate and periodic groups were similar. There were major differences between the periodic and regular groups. The infants breathing periodically (1) hypoventilated, (2) showed a significant shift of the CO2 response curve to the right with a 22% decrease in slope, and (3) had an increased response to O2. However, the two groups had similar alveolar-capillary PO2 and PCO2 differences. These findings suggest that the major defect is not in the lungs or at the peripheral chemoreceptors but at the respiratory center (or central receptors).

Chemoreceptor Reflexes in Preterm Infants: II. The Effect of Gestational and Postnatal Age on the Ventilatory Response to Inhaled Carbon Dioxide

PEDIATRICS ◽  
1975 ◽  
Vol 55 (5) ◽  
pp. 614-620 ◽  
Author(s):  
Henrique Rigatto ◽  
June P. Brady ◽  
Rafael de la Torre Verduzco
Keyword(s):  
Carbon Dioxide ◽  
Heart Rate ◽  
Preterm Infants ◽  
Dead Space ◽  
Ventilatory Response ◽  
Gas Mixtures ◽  
Postnatal Life ◽  
Constant Flow ◽  
Flow Through ◽  
Carbon Dioxide Response

We studied nine "healthy" preterm infants (birthweight, 1,000 to 2,000 gm) 58 times during postnatal life to define the effects of gestational and postnatal age on the ventilatory response to carbon dioxide. The infants were given air and 2% and 4% carbon dioxide in air to breathe for five minutes each. We determined respiratory minute and tidal volumes, frequency, heart rate, and alveolar Pco2 and Po2. We measured ventilation with a nosepiece and a screen flowmeter, using a constant flow-through to eliminate valves and reduce dead space. Analyses were made during the fifth minute while the baby breathed the various gas mixtures. The slope of the carbon dioxide response increased 42% from 32 to 37 weeks gestation (P &lt; .05) and 62% from 2 to 27 days of age (P &lt; .025). However, the intercept at .3 liter/mm/kg was the same at different gestational ages, but significantly greater at 2 compared with 27 days of age (P &lt; .05). We suggest that the unresponsiveness with increasing prematurity is primarily central and that after birth is primarily dependent on the mechanical abnormalities of the lung.

Effect of temperature on central chemical control of ventilation in the alligator Alligator mississippiensis

1993 ◽  
Vol 179 (1) ◽  
pp. 261-272
Author(s):  
L. G. Branco ◽  
S. C. Wood
Keyword(s):  
Fourth Ventricle ◽  
Ventilatory Response ◽  
Pulmonary Ventilation ◽  
Gas Mixtures ◽  
Alligator Mississippiensis ◽  
Effect Of Temperature ◽  
Peripheral Chemoreceptor ◽  
Peripheral Chemoreceptors ◽  
Ph Values ◽  
Arterial Ph

Central chemoreceptor function was assessed in unanesthetized alligators, Alligator mississippiensis, at body temperatures of 15, 25 and 35 degrees C. Two experiments were performed. In the first experiment, the fourth ventricle was perfused with mock cerebrospinal fluid (CSF) solutions of different pH values (7.1-7.9). Changes in pulmonary ventilation were evaluated with a pneumotachograph and arterial pH (pHa) was measured. Perfusion with low-pH solutions increased ventilation and arterial pH. Perfusion with high-pH solutions decreased ventilation and arterial pH. Mock CSF pH had a greater effect at higher temperatures. In the second experiment, the relative contributions of central and peripheral chemoreceptor drive to breathing were evaluated using hypercapnic gas mixtures to stimulate both central and peripheral chemoreceptors. Hypercapnia caused an increase in ventilation which was larger at higher temperatures. To stimulate only the peripheral chemoreceptors, the same hypercapnic gas mixtures were applied while the CSF pH of the fourth ventricle was kept constant by perfusion with a mock CSF solution. This reduced significantly the ventilatory response induced by hypercapnia. These data indicate that, regardless of the temperature, central chemoreceptors play a major role in the ventilatory regulation of the alligator. The change in pHa with temperature is compatible with the alphastat hypothesis.

Ventilatory effects of acetazolamide in cats during hypoxemia

1992 ◽  
Vol 72 (5) ◽  
pp. 1717-1723 ◽  
Author(s):  
L. J. Teppema ◽  
F. Rochette ◽  
M. Demedts
Keyword(s):  
Steady State ◽  
Ventilatory Response ◽  
Significant Rise ◽  
Hypoxic Ventilatory Response ◽  
Peripheral Chemoreceptor ◽  
Peripheral Chemoreceptors ◽  
Relative Contribution ◽  
Ventilatory Effects ◽  
Arterial Po2 ◽  
Mean Alveolar Pco2

In normoxemic cats, acetazolamide (ACTZ) has been shown to cause a large rise in ventilation (VE) but a decrease in peripheral chemoreceptor activity. The relative contribution of the peripheral chemoreceptors to ventilation is higher during hypoxemia than during normoxemia. Therefore, what are the effects of ACTZ during steady-state hypoxemia? The aims of this study in anesthetized cats were 1) to study the effect of ACTZ (50 mg/kg iv) on mean hypoxemic [arterial PO2 (PaO2) approximately 6 kPa] ventilation and 2) to study the effect of ACTZ on the isocapnic hypoxic ventilatory response. In the first study, in six cats with an inspiratory CO2 fraction of 0, ACTZ led to an insignificant rise in mean VE of 119 ml.min-1.kg-1 after 1 h. In five other cats maintained at an inspiratory CO2 fraction of 0.015, ACTZ resulted in a significantly larger response in VE (268 and 373 ml.min-1.kg-1 after 1 and 2 h, respectively). In the second study, before infusion in five cats, an isocapnic fall in mean PaO2 from 13 to 4.7 kPa led to a significant rise in mean VE of 385 ml.min-1.kg-1; 1 h later, the response (at the same mean alveolar PCO2) was reduced to an insignificant rise of 38 ml.min-1.kg-1. Before infusion four other cats showed a significant rise in mean VE of 390 ml.min-1.kg-1 when mean PaO2 was lowered isocapnically from 12.4 to 6.8 kPa; 2 h after infusion, an isocapnic fall in mean PaO2 from 13.9 to 7.2 kPa led to an insignificant rise of 112 ml.min-1.kg-1.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Intravenous adenosine and dyspnea in humans

2005 ◽  
Vol 98 (1) ◽  
pp. 180-185 ◽  
Author(s):  
Nausherwan K. Burki ◽  
Wheeler J. Dale ◽  
Lu-Yuan Lee
Keyword(s):  
Heart Rate ◽  
Heart Rate Response ◽  
Ventilatory Response ◽  
Normal Subjects ◽  
Peripheral Chemoreceptor ◽  
C Fibers ◽  
Group Data ◽  
Lung Resistance ◽  
Time Latency ◽  
Stimulation Of

Intravenous adenosine for the treatment of supraventricular tachycardia is reported to cause bronchospasm and dyspnea and to increase ventilation in humans, but these effects have not been systematically studied. We therefore compared the effects of 10 mg of intravenous adenosine with placebo in 21 normal subjects under normoxic conditions and evaluated the temporal sequence of the effects of adenosine on ventilation, dyspnea, and heart rate. The study was repeated in 11 of these subjects during hyperoxia. In all subjects, adenosine resulted in the development of dyspnea, assessed by handgrip dynamometry, without any significant change ( P > 0.1) in lung resistance as measured by the interrupter technique. There were significant increases ( P < 0.05) in ventilation and heart rate in response to adenosine. The dyspneic response occurred slightly before the ventilatory or heart rate responses in every subject, but the timing of the dyspneic, ventilatory, and heart rate responses was not significantly different when the group data were analyzed (18.9 ± 5.8, 20.3 ± 5.5, and 19.7 ± 4.5 s, respectively). During hyperoxia, adenosine resulted in similar effects, with no significant differences in the magnitude of the ventilatory response; however, compared with the normoxic state, the intensity of the dyspneic response was significantly ( P < 0.05) reduced, whereas the heart rate response increased significantly ( P < 0.05). These data indicate that intravenous adenosine-induced dyspnea is not associated with bronchospasm in normal subjects. The time latency of the response indicates that the dyspnea is probably not a consequence of peripheral chemoreceptor or brain stem respiratory center stimulation, suggesting that it is most likely secondary to stimulation of receptors in the lungs, most likely vagal C fibers.

Ventilatory response in the fetal lamb following peripheral chemodenervation

1977 ◽  
Vol 42 (4) ◽  
pp. 630-635 ◽  
Author(s):  
D. E. Woodrum ◽  
T. A. Standaert ◽  
C. R. Parks ◽  
D. Belenky ◽  
J. Murphy ◽  
...  
Keyword(s):  
Ventilatory Response ◽  
Blood Gases ◽  
System Control ◽  
Fetal Blood ◽  
Peripheral Chemoreceptor ◽  
Peripheral Chemoreceptors ◽  
Marked Variability ◽  
Fetal Lamb ◽  
Before And After ◽  
Chemical Stimuli

Carotid infusions of sodium cyanide solution and perfusions of hypoxemic or hypercapnic fetal blood were done before and after peripheral chemoreceptor denervation. Step changes in PaO2 ranged from -11 to -22 Torr; step changes in PaCO2 ranged from +17 to +42 Torr. The cyanide dose was 0.2 mg/kg per loop system. Control perfusions consisted of 25 ml of fetal blood without changes in pH and blood gases. A ventilatory response occurred in the majority of all experimental perfusions regardless of innervation status of the peripheral chemoreceptors. No response occurred with control perfusions. There was a marked variability in the time of onset of ventilatory activity with a delay of greater than 10 s occurring following most perfusions. These studies demonstrate that the fetus has an attenuated ventilatory response to chemical stimuli and that hypoxia stimulates ventilation in the absence of peripheral chemoreceptors.

Blood Transfusion Effect on the Respiratory Pattern of Preterm Infants

PEDIATRICS ◽  
1987 ◽  
Vol 80 (1) ◽  
pp. 79-84
Author(s):  
Ashok Joshi ◽  
Tilo Gerhardt ◽  
Patty Shandloff ◽  
Eduardo Bancalari
Keyword(s):  
Heart Rate ◽  
Preterm Infants ◽  
Breathing Pattern ◽  
Total Duration ◽  
Periodic Breathing ◽  
Respiratory Center ◽  
Respiratory Pattern ◽  
Increased Risk ◽  
Before And After ◽  
Irregular Breathing

Anemia may increase the risk of tissue hypoxia in preterm infants. This could lead to respiratory center depression and an increased risk for apnea. Heart rate and breathing pattern were recorded in 30 preterm infants (gestational age 30.0 ± 2.3 weeks, postnatal age 46.6 ± 20.8 days, and weight 1,438 ± 266 g) before and after a transfusion of 10 mL/kg of packed RBCs. All infants were stable clinically, breathing room air, and free of prolonged apneic episodes. After transfusion, hematocrit levels increased from 27.0% ± 2.5% to 35.8% ± 4.7%. Heart rate decreased from 157.2 ± 13.6 beats per minute to 148.4 ± 13.9 beats per minute. There was no change in respiratory rate or BP. The duration of periodic breathing decreased significantly, as did the duration of the longest periodic breathing episode (P &lt; .01). The number of respiratory pauses lasting 5 to 10 seconds and the number of pauses lasting 11 to 20 seconds also decreased significantly (P &lt; .05). The total duration of respiratory pauses, excluding pauses during periodic breathing, were significantly lower after transfusion (P &lt; .05), as was the number of episodes of bradycardia. These results indicate that preterm infants have a more irregular breathing pattern while anemic than after correction of the anemia. The irregular breathing pattern is probably caused by mild hypoxic respiratory center depression.

Use of Individualized Versus Standard Criteria to Identify Abnormal Levels of Heart Rate or Oxygen Saturation in Preterm Infants

2001 ◽  
Vol 9 (2) ◽  
pp. 181-200 ◽  
Author(s):  
Lynda Harrison ◽  
Michael L. Berbaum ◽  
John T. Stem ◽  
Katherine Peters
Keyword(s):  
Heart Rate ◽  
Oxygen Saturation ◽  
Preterm Infants ◽  
Neonatal Intensive Care ◽  
Physiological Responses ◽  
Clinical Effectiveness ◽  
Low Oxygen ◽  
Heart Rates ◽  
Developmental Care ◽  
Physiological Indicators

Preterm infants’ physiological indicators, such as heart rate, respiratory rate, and oxygen saturation levels, are routinely monitored by devices that can alert nurses to threatening changes in condition. Most Neonatal Intensive Care Units use standard criteria as alerting algorithms to determine when an alert should be issued, and these standard criteria have been adopted uncritically in studies of preterm infants. This article presents results from a study examining preterm infants’ physiological responses to a gentle human touch (GHT) intervention in which we compared the use of standard and individualized criteria to define the percentages of abnormally low and high heart rates (HRs) and abnormally low oxygen saturation (O2 sat) levels before, during, and after periods of GHT. Results indicated that there were no differences in the percentages of abnormal HRs or O2 sat values between periods using standard criteria. However, using individualized criteria, there were significantly greater percentages of abnormally low heart rates and O2 sat levels during and after GHT periods as compared to baseline periods. The findings suggest that standard criteria may not be sensitive enough to detect subtle physiological responses to environmental stimuli such as touch. Moreover, consistent with the recognition of the value of individualized developmental care, these results suggest that the clinical effectiveness of individualized criteria for setting monitor alert limits merits further investigation.

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