CO2-induced changes in ventilation and ventilatory pattern in normal sleeping infants

Haddad, Gabriel G.; Leistner, Hedi L.; Epstein, Robert; Epstein, Miles L.; Grodin, W. K.; Mellins, Robert B.

doi:10.1152/jappl.1980.48.4.684

Cited by 42 publications

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“…Most ventilatory response studies to CO2 have been performed on premature and term neonates exposed to relatively high ($3%) concentrations of CO2. However, using steady state 2% CO2, Schafer et al (1993) found that minute ventilation increased by 17-33% in infants aged #18 mon old, and in infants aged #4 mon Haddad et al (1980) reported an average increase of 33%. In both studies, the ventilatory response largely resulted from increased tidal volume (not measured in our study), with little change in respiratory frequency.…”

Section: Discussionmentioning

confidence: 98%

“…Incorporating current hypotheses on the constitutional deficits involved in SIDS, which include cardiovascular, respiratory, arousal and thermoregulatory defects, we have postulated that, in some contexts, either fundamental sensory features inherent to bedsharing with a parent and/or caretaking behaviors of parents during bedsharing might offer protection against SIDS (Mosko et al, 1993McKenna et al, 1990;Richard et al, 1996). The possibility that maternal respiration could elevate the infant's CO2 environment is important from the standpoint that increased CO2 can have diverse effects, ranging from respiratory stimulation at low levels to suffocation at very high levels (Schafer et al, 1993;Haddad et al, 1980;Chiodini and Thach, 1993;Kemp et al, 1994). Evidence of respiratory stimulation as a result of bedsharing could be important in the context of compensation for a postulated impairment in respiratory control mechanisms in the etiology of SIDS.…”

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confidence: 99%

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Maternal proximity and infant CO2 environment during bedsharing and possible implications for SIDS research

Mosko

Richard

McKenna

et al. 1997

Am. J. Phys. Anthropol.

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Sudden infant death syndrome (SIDS) is the leading cause of human infant mortality after the neonatal period in Western countries. Recently, child care practices have been shown to be important in determining infant vulnerability to SIDS. However, very little is known about the impact of parent-infant cosleeping on infant sleep physiology and behavior and SIDS risk. This reflects the failure of Western societal research paradigms to appreciate the human infant's evolutionary history of cosleeping, the recency of the emergence of solitary infant sleeping as a practice and the fact that parent-infant cosleeping is still the preferred sleeping arrangement for the majority of contemporary societies. Incorporating current hypotheses on the mechanisms of SIDS, we have hypothesized that the comparatively sensory-rich cosleeping environment might be protective against SIDS in some contexts. As a first step to characterize cosleeping environments, this investigation is aimed at assessing, in routinely bedsharing mothers and infants, their relative sleeping positions and the potential for sleeping in close face-to face proximity and for infant exposure to increased environmental CO2 produced by maternal respiration. The latter is important in that breathing elevated levels of CO2 can have diverse effects, ranging from respiratory stimulation at low levels to suffocation at very high levels. Two related laboratory studies were performed. In the first, all-night videotapes of 12 healthy, routinely bedsharing mother-infant pairs were analyzed for sleeping positions and time spent in face-to-face orientation and distances separating their faces. Infants were 11-15 wk old. Mothers predominantly positioned themselves on their sides facing their infants, with the infants placed either supine or on their sides. Mothers and infants slept oriented face-to-face for 64 +/- 27% (S.D.) of non-movement time, with distance less than 20 cm commonly separating their faces. In the second study, concentrations of CO2 in air were measured in six young women at distances of up to 21 cm from their nares. Peak expiratory CO2 concentrations remained above 1.0% at distances up to 9 cm and above 0.5% at 18 cm. Both baseline and peak CO2 levels were further increased at all distances when measured within a partial air pocket created to simulate a bedding environment sometimes seen during bedsharing. We conclude that during bedsharing there is potential for 1) a high degree of face-to-face orientation and close proximity and consequently 2) increased environmental CO2, as a result of maternal respiration, to non-lethal levels that might stimulate infant respiration. The close proximity would also maximize the sensory impact of the mother on the infant through other modalities. We also suggest that bedsharing may minimize prone infant positioning, a known risk factor for SIDS.

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Section: Discussionmentioning

confidence: 98%

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confidence: 99%

Maternal proximity and infant CO2 environment during bedsharing and possible implications for SIDS research

Mosko

Richard

McKenna

et al. 1997

Am. J. Phys. Anthropol.

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“…During postnatal life, the CO2 sensitivity increases during the first month in preterm infants and in both premature and full-term primates [20,21], although in puppies, the percent changes in ventilation in response to a low level of CO2 (2%) does not change be tween 2 weeks and 4 months of age [22], Simi larly, we have found in a recent work that in 16 conscious kittens, the ventilatory response to 3 and 5% CO2 increases between 2 and 4 weeks of age ( fig. 1).…”

Section: Ventilatory Response To Hypercapniamentioning

confidence: 99%

Ventilatory Strategy in Hypoxic or Hypercapnic Newborns

Bonora

Boulé²,

Gautier³

1994

Neonatology

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In conscious newborns, the ventilatory response to hypoxia is characterized by precocious hyperventilation followed by tardive hypoventilation, the latter disappearing with age. The hypoventilation could be mainly related to a weak peripheral drive and to the persistence of the diaphragmatic activity during expiration. Also, a decrease in metabolic rate and body temperature interferes with the response. The hyperventilation in response to hypercapnia increases as maturation proceeds and the maturation of the peripheral chemoreceptors contribute to this effect, as during hypoxia. The responses to both stimuli depend on many factors such as sleep state, anesthesia or ambient temperature.

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“…Steady-state CO 2 sensitivity increased after birth in some (6 -8) but not all species (9). Preterm infants displayed an age-related increase in steady-state CO 2 sensitivity (10, 11), whereas term infants showed no such postnatal development (12,13). Dynamic CO 2 sensitivity was unchanged during the first month in neonatal lambs (8,14), whereas in piglets the relative contribution of peripheral chemoreceptors to CO 2 stimulation increased postnatally (15).…”

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Development of Ventilatory Response to Transient Hypercapnia and Hypercapnic Hypoxia in Term Infants

Søvik

Lossius

2004

Pediatr Res

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Whereas peripheral chemoreceptor oxygen sensitivity increases markedly after birth, previous studies of ventilatory responses to CO 2 in term infants have shown no postnatal development. However, the hypercapnic challenges applied have usually been long-term, which meant that the effect of central chemoreceptors dominated. Oscillatory breathing, apneas, and sighs cause transient PCO 2 changes, probably primarily stimulating peripheral chemoreceptors. We wanted to assess whether the immediate ventilatory responses to step changes in inspired CO 2 and O 2 in term infants undergo postnatal developmental changes. Twenty-six healthy term infants were studied during natural sleep 2 d and 8 wk postnatally. Ventilatory responses to a randomized sequence of 15 s hypercapnia (3% CO 2 ), hypoxia (15% O 2 ), and hypercapnic hypoxia (3% CO 2 ϩ 15% O 2 ) were recorded breath-by-breath using a pneumotachometer. Response rate, stimulus-response time, and response magnitude were analyzed with ANOVA after coherent averaging. Response rate increased with age by 30% (hypercapnia), 318% (hypoxia), and 302% (hypercapnic hypoxia). Response rate during hypercapnic hypoxia exceeded rate during hypercapnia plus rate during hypoxia in wk 8, but not on d 2. Time to half-maximum response decreased by 3.4 s with age for the two hypercapnic stimuli but was unchanged for hypoxia. Response magnitude was unchanged for hypercapnia, but increased for the two hypoxic stimuli. In conclusion, an interaction between the effects of hypercapnia and hypoxia on ventilatory response rate emerged between postnatal d 2 and wk 8 in term infants. Concomitantly, stimulus-response time to hypercapnic stimuli declined markedly. Peripheral and central chemoreceptors are crucial for the precise control of respiration. The carotid, aortic, and central chemoreceptors are functional even in fetal life (1, 2), but the transition to continuous breathing calls for rapid adjustments. The marked increase in arterial PO 2 at birth brings about a corresponding resetting of carotid and aortic chemoreceptor O 2 sensitivity, which takes place during the first postnatal days and weeks (1,(3)(4)(5). In contrast, studies of postnatal CO 2 chemosensitivity show divergent results. Steady-state CO 2 sensitivity increased after birth in some (6 -8) but not all species (9). Preterm infants displayed an age-related increase in steady-state CO 2 sensitivity (10, 11), whereas term infants showed no such postnatal development (12, 13). Dynamic CO 2 sensitivity was unchanged during the first month in neonatal lambs (8,14), whereas in piglets the relative contribution of peripheral chemoreceptors to CO 2 stimulation increased postnatally (15).Ultimately, the combined effects of PCO 2 , arterial PO 2 , and pH determine the level of ventilation. Nonlinear interaction between PCO 2 and PO 2 , i.e. increased CO 2 chemosensitivity at increasing levels of hypoxia, has been described in carotid and aortic nerve recordings (7,8,16) and in ventilatory responses in animals (17, 18) and adult humans (1...

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CO2-induced changes in ventilation and ventilatory pattern in normal sleeping infants

Cited by 42 publications

References 0 publications

Maternal proximity and infant CO2 environment during bedsharing and possible implications for SIDS research

Maternal proximity and infant CO2 environment during bedsharing and possible implications for SIDS research

Ventilatory Strategy in Hypoxic or Hypercapnic Newborns

Development of Ventilatory Response to Transient Hypercapnia and Hypercapnic Hypoxia in Term Infants

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