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 inhaled oxygen (up to 40%) on periodic breathing and apnea in preterm infants

1992 ◽  
Vol 72 (1) ◽  
pp. 116-120 ◽  
Author(s):  
Z. Weintraub ◽  
R. Alvaro ◽  
K. Kwiatkowski ◽  
D. Cates ◽  
H. Rigatto
Keyword(s):  
Birth Weight ◽  
Tidal Volume ◽  
Preterm Infants ◽  
Gestational Age ◽  
Minute Ventilation ◽  
Periodic Breathing ◽  
Respiratory Pattern ◽  
Quiet Sleep ◽  
Flow Through ◽  
Transcutaneous Po2

To discover whether increases in inhaled O2 fraction (FIO2; up to 40%) decrease apnea via an increase in minute ventilation (VE) or a change in respiratory pattern, 15 preterm infants (birth weight 1,300 +/- 354 g, gestational age 29 +/- 2 wk, postnatal age 20 +/- 9 days) breathed 21, 25, 30, 35, and 40% O2 for 10 min in quiet sleep. A nosepiece and a flow-through system were used to measure ventilation. Alveolar PCO2, transcutaneous PO2, and sleep states were also assessed. All infants had periodic breathing with apneas greater than or equal to 3 s. With an increase in FIO2 breathing became more regular and apneas decreased (P less than 0.001). This regularization in breathing was not associated with significant changes in VE. However, the variability of VE, tidal volume, and expiratory and inspiratory times decreased significantly. The results indicate that the more regular breathing observed with small increases in FIO2 was not associated with significant changes in ventilation. The findings suggest that the increased oxygenation decreases apnea and periodicity in preterm infants, not via an increase in ventilation, but through a decrease in breath-to-breath variability of VE.

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.

Ventilatory response to hypoxia in unanesthetized newborn kittens

1988 ◽  
Vol 64 (6) ◽  
pp. 2544-2551 ◽  
Author(s):  
H. Rigatto ◽  
C. Wiebe ◽  
C. Rigatto ◽  
D. S. Lee ◽  
D. Cates
Keyword(s):  
Tidal Volume ◽  
Chest Wall ◽  
Ventilatory Response ◽  
Minute Ventilation ◽  
Respiratory Frequency ◽  
Quiet Sleep ◽  
Newborn Kitten ◽  
Peripheral Mechanism ◽  
Flow Through ◽  
Ventilatory Response To Hypoxia

We studied the ventilatory response to hypoxia in 11 unanesthetized newborn kittens (n = 54) between 2 and 36 days of age by use of a flow-through system. During quiet sleep, with a decrease in inspired O2 fraction from 21 to 10%, minute ventilation increased from 0.828 +/- 0.029 to 1.166 +/- 0.047 l.min-1.kg-1 (P less than 0.001) and then decreased to 0.929 +/- 0.043 by 10 min of hypoxia. The late decrease in ventilation during hypoxia was related to a decrease in tidal volume (P less than 0.001). Respiratory frequency increased from 47 +/- 1 to 56 +/- 2 breaths/min, and integrated diaphragmatic activity increased from 14.9 +/- 0.9 to 20.2 +/- 1.4 arbitrary units; both remained elevated during hypoxia (P less than 0.001). Younger kittens (less than 10 days) had a greater decrease in ventilation than older kittens. These results suggest that the late decrease in ventilation during hypoxia in the newborn kitten is not central but is due to a peripheral mechanism located in the lungs or respiratory pump and affecting tidal volume primarily. We speculate that either pulmonary bronchoconstriction or mechanical uncoupling of diaphragm and chest wall may be involved.

Hypoxic Arousal Responses in Normal Infants

PEDIATRICS ◽  
1992 ◽  
Vol 89 (5) ◽  
pp. 860-864 ◽  
Author(s):  
Sally L. Davidson Ward ◽  
Daisy B. Bautista ◽  
Thomas C. Keens
Keyword(s):  
Ventilatory Response ◽  
Arterial Oxygen Saturation ◽  
Periodic Breathing ◽  
High Risk Group ◽  
Arterial Oxygen ◽  
Sudden Infant ◽  
Hypoxic Ventilatory Response ◽  
Quiet Sleep ◽  
Term Infants ◽  
Increased Risk

Failure to arouse in response to hypoxia has been described in infants at increased risk for sudden infant death syndrome (SIDS) and has been suggested as a possible mechanism for SIDS. However, most SIDS victims are not in a high-risk group before death. Thus, if a hypoxic arousal disorder is an important contributor to SIDS, normal infants might fail to arouse from sleep in response to hypoxia. To test this hypothesis, the authors studied hypoxic arousal responses in 18 healthy term infants younger than 7 months of age (age 12.1 ± 1.7 [SEM] weeks; 56% girls). Hypoxic arousal challenges were performed during quiet sleep by rapidly decreasing inspired oxygen tension (Pio2) to 80 mm Hg for 3 minutes or until arousal (eye opening, agitation, and crying) occurred. Tests were performed in duplicate when possible. Only 8 infants (44%) aroused in response to one or more hypoxic challenges; arousal occurred during 8 (32%) of 25 trials. There were no significant differences in lowest Pio2 or arterial oxygen saturation during hypoxia between those infants who aroused and those who failed to arouse. All 18 infants had a fall in their end-tidal carbon dioxide tension during hypoxia, suggesting that each had a hypoxic ventilatory response despite failure to arouse in the majority. Periodic breathing occurred following hypoxia in only 1 (13%) of the 8 trials that resulted in arousal, compared with 16 (94%) of 17 trials without arousal (P &lt; .005). It is concluded that the majority of normal infants younger than 7 months of age fail to arouse from quiet sleep in response to hypoxia, despite the apparent presence of a hypoxic ventilatory response.

Reduction of Sleep Apnea and Bradycardia in Preterm Infants on Oscillating Water Beds: A Controlled Polygraphic Study

PEDIATRICS ◽  
1978 ◽  
Vol 61 (4) ◽  
pp. 528-533
Author(s):  
Anneliese F. Korner ◽  
Christian Guilleminault ◽  
Johanna Van den Hoed ◽  
Roger B. Baldwin
Keyword(s):  
Birth Weight ◽  
Sleep Apnea ◽  
Preterm Infants ◽  
Premature Infants ◽  
Gestational Age ◽  
Periodic Breathing ◽  
Quiet Sleep ◽  
Severe Bradycardia

The sleep and respiratory patterns of eight apneic preterm infants were polygraphically recorded for 24 hours. This polygraphic study was designed to test and extend our previous finding that gently oscillating water beds reduce apnea in premature infants. The infants who ranged in gestational age from 27 to 32 weeks and in birth weight from 1,077 to 1,650 gm served as their own controls, off and on the water bed. The 24-hour recordings were divided into four time blocks with the infant being placed on the water bed during alternate six-hour periods. Apnea was significantly reduced while the infants were on the oscillating water beds, with the longest apneic periods and those associated with severe bradycardia being reduced the most. Reduction of apnea was most consistent during indeterminate sleep and most pronounced during quiet sleep. Short respiratory pauses and periodic breathing were not significantly reduced. Reductions of central, obstructive, and mixed apneas were approximately equal.

Effect of a single breath of 100% oxygen on respiration in neonates during sleep

1984 ◽  
Vol 57 (5) ◽  
pp. 1531-1535 ◽  
Author(s):  
T. Aizad ◽  
J. Bodani ◽  
D. Cates ◽  
L. Horvath ◽  
H. Rigatto
Keyword(s):  
Gestational Age ◽  
Minute Ventilation ◽  
Control Period ◽  
Full Term ◽  
Preterm Neonates ◽  
Sleep State ◽  
Quiet Sleep ◽  
Peripheral Chemoreceptor ◽  
Term Infants ◽  
Single Breath

To determine the effect of a single breath of 100% O2 on ventilation, 10 full-term [body wt 3,360 +/- 110 (SE) g, gestational age 39 +/- 0.4 wk, postnatal age 3 +/- 0.6 days] and 10 preterm neonates (body wt 2,020 +/- 60 g, gestational age 34 +/- 2 wk, postnatal age 9 +/- 2 days) were studied during active and quiet sleep states. The single-breath method was used to measure peripheral chemoreceptor response. To enhance response and standardize the control period for all infants, fractional inspired O2 concentration was adjusted to 16 +/- 0.6% for a control O2 saturation of 83 +/- 1%. After 1 min of control in each sleep state, each infant was given a single breath of O2 followed by 21% O2. Minute ventilation (VE), tidal volume (VT), breathing frequency (f), alveolar O2 and CO2 tension, O2 saturation (ear oximeter), and transcutaneous O2 tension were measured. VE always decreased with inhalation of O2 (P less than 0.01). In quiet sleep, the decrease in VE was less in full-term (14%) than in preterm (40%) infants (P less than 0.001). Decrease in VE was due primarily to a drop in VT in full-term infants as opposed to a fall in f and VT in preterm infants (P less than 0.05). Apnea, as part of the response, was more prevalent in preterm than in full-term infants. In active sleep the decrease in VE was similar both among full-term (19%) and preterm (21%) infants (P greater than 0.5). These results suggest greater peripheral chemoreceptor response in preterm than in full-term infants, reflected by a more pronounced decrease in VE with O2. The results are compatible with a more powerful peripheral chemoreceptor contribution to breathing in preterm than in full-term infants.

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).

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.

scholarly journals Determinants of long-term facilitation in humans during NREM sleep

2003 ◽  
Vol 94 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Mark Babcock ◽  
Mahdi Shkoukani ◽  
Salah E. Aboubakr ◽  
M. Safwan Badr
Keyword(s):  
Minute Ventilation ◽  
Linear Regression Analysis ◽  
Recovery Period ◽  
Control Period ◽  
Inspiratory Flow ◽  
Flow Limitation ◽  
Peripheral Chemoreceptor ◽  
Long Term Facilitation ◽  
Independent Determinant

Long-term facilitation (LTF) is a prolonged increase in ventilatory motor output after episodic peripheral chemoreceptor stimulation. We have previously shown that LTF is activated during sleep following repetitive hypoxia in snorers (Babcock MA and Badr MS. Sleep 21: 709–716, 1998). The purpose of this study was 1) to ascertain the relative contribution of inspiratory flow limitation to the development of LTF and 2) to determine the effect of eliminating inspiratory flow limitation by nasal CPAP on LTF. We studied 25 normal subjects during stable non-rapid eye movement sleep. We induced 10 episodes of brief repetitive isocapnic hypoxia (inspired O2 fraction = 8%; 3 min) followed by 5 min of room air. Measurements were obtained during control and at 20 min of recovery (R20). During the episodic hypoxia study, inspiratory minute ventilation (V˙i) increased from 6.7 ± 1.9 l/min during the control period to 8.2 ± 2.7 l/min at R20 (122% of control; P < 0.05). Linear regression analysis confirmed that inspiratory flow limitation during control was the only independent determinant of the presence of LTF ( P = 0.005). Six subjects were restudied by using nasal continuous positive airway pressure to ascertain the effect of eliminating inspiratory flow limitation on LTF.V˙i during the recovery period was 97 ± 10% ( P > 0.05). In conclusion, 1) repetitive hypoxia in sleeping humans is followed by increasedV˙i in the recovery period, indicative of development of LTF; 2) inspiratory flow limitation is the only independent determinant of posthypoxic LTF in sleeping human; 3) elimination of inspiratory flow limitation abolished the ventilatory manifestations of LTF; and 4) we propose that increased V˙i in the recovery period was a result of preferential recruitment of upper airway dilators by repetitive hypoxia.

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