Delayed chemoreceptor responses in infants with apnoea

Katz‐Salamon, Miriam

doi:10.1136/adc.2003.030957

Cited by 38 publications

(16 citation statements)

References 33 publications

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“…Changes in arterial O 2 pressure levels [caused by chronic hypoxemia at birth (30) or hypoxia-induced changes in arterial CO 2 (31)] may determine the sensitivity to hypoxia, which interferes with postnatal readjustment of the chemoreflex. This statement could, however, be subject to criticism as there is no evidence that the changes in transcutaneous O 2 are closely related to arterial O 2 pressure [with a slower response time for transcutaneous O 2 , in particular (7,32)], whereas another study showed that PaO 2 varied broadly with SpO 2 and that the latter accurately reflected the simultaneous PaO 2 (33). Moreover, borderline hypoxemia could exist without a decrease in saturation (10).…”

Section: Discussionmentioning

confidence: 99%

Ventilatory Response to a Hyperoxic Test Is Related to the Frequency of Short Apneic Episodes in Late Preterm Neonates

et al. 2007

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ABSTRACT:Chemoreception is frequently involved in the processes underlying apnea in premature infants. Apnea could result from a decrease in carotid body effectiveness. However, increased carotid body activity could also initiate apnea through hypocapnia following hyperventilation when the receptors are stimulated. The aim of this study was to analyze the relationship between carotid body effectiveness and short apneic episodes in older preterm neonates. Carotid body effectiveness was assessed at thermoneutrality in 36 premature neonates (2.07 Ϯ 0.26 kg) by performing a 30-s hyperoxic test during sleep, the oxygen inhalation involving a ventilation decrease. Blood O 2 saturation (Sp O2 ) and ventilatory parameters were monitored before and during the hyperoxic test. Short episodes of apnea (frequency and mean duration) were recorded during the morning's 3-h interfeeding interval. Pretest Sp O2 was not related to any of the measured respiratory parameters. A higher frequency of short apneic episodes was linked to a greater ventilation decrease in response to the hyperoxic test ( ϭ Ϫ0.32; p ϭ 0.01). Increased carotid body response is correlated with greater apneic episodes frequency, even in the absence of concomitant oxygen desaturation. Fetal or early postnatal hypoxemia could have increased peripheral chemoreceptor activity, which could initiate a "overshoot/ undershoot" situation, which in turn could induce a critical P O2 /P CO2 combination and apnea. (Pediatr Res 62: 591-596, 2007) S hort apneic episodes [defined as a respiratory pause of at least 3 s (1,2)] are common respiratory events in premature neonates, with an incidence of 25% in infants weighing Ͻ2500 g at birth and 84% in those weighing Ͻ1000 g (3).After birth, apnea frequency decreases progressively once chemoreception control is sufficiently developed to initiate the appropriate ventilatory responses to changes in arterial blood gas status (3-6). Chemoreception control is carried out by central and peripheral chemoreceptors that differ in their anatomical location and type of stimulation: peripheral chemoreceptors (mainly carotid bodies) are sensitive to variations in the levels of O 2 and (to a lesser extent) CO 2 , whereas central chemoreceptors are especially sensitive to variations in CO 2 and pH.It is accepted that abnormal functioning of the peripheral chemoreceptors can promote apnea even though the mechanism underlying this altered chemoreceptor activity is still subject to much debate. Provision of oxygen to infants suffering from bronchopulmonary dysplasia delays the peripheral chemoreceptor response and might induce more apnea (7). In preterm neonates, an increase in the chemoreceptor gain during the postnatal period has also been suggested. The latter can initiate an "overshoot/undershoot" situation: the apnea results from a central depression in inspiratory motor drive, which is mainly due to hypocapnia. This concept has been described in adult dogs to explain periodic breathing (8) and extended to the newborn lamb (9), but physiolog...

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Section: Discussionmentioning

confidence: 99%

Ventilatory Response to a Hyperoxic Test Is Related to the Frequency of Short Apneic Episodes in Late Preterm Neonates

et al. 2007

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“…It has been further suggested that infants with central SAH events may have depressed or delayed ventilation responses to hypercarbia and possibly hypoxemia regardless of their apnoeic severity. In order to meet homoeostatic demands, the respiratory control mechanisms in the brain stem must be able to detect and respond to changes in arterial carbon dioxide and oxygen levels in a rapid manner [1,2]. The strength and timing of the ventilation response can then have confounding effects.…”

Section: Discussionmentioning

confidence: 99%

“…The clinical symptoms and PSG characteristics of SAH for infants differ from those in children and adults [1,2]. Infantile SAH usually results from congenital facial anomalies and neurological abnormalities that involve muscle tone and upper airway control [2,3]. Unlike children and adults, SAH in an infant can present a unique threat to life, such as sudden infant death syndrome and premature apnoea.…”

Section: Introductionmentioning

confidence: 98%

“…Polysomnography (PSG) is considered to be the current gold standard procedure for investigating SAH in infants. The clinical symptoms and PSG characteristics of SAH for infants differ from those in children and adults [1,2]. Infantile SAH usually results from congenital facial anomalies and neurological abnormalities that involve muscle tone and upper airway control [2,3].…”

Section: Introductionmentioning

confidence: 99%

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An investigation on pulse transit time in respiratory sleep studies for infants

Foo

Lim

2008

Journal of Medical Engineering & Technology

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The main objective of this study was to assess the capability of pulse transit time (PTT) to identify obstructive and/or central apnoeas from normal breathing patterns in sleeping infants. Clinical trials were conducted with PTT being monitored as an adjunct measure in routine overnight polysomnography (PSG) studies. Standard PSG scorings of events were performed by two blinded observers to evaluate PTT accuracy. Data from eight infants (six male; aged 8.5 + 2.1 months; apnoea-hypopnoea index of 12.1 + 8.4 events per hour) were collected. Obstructive events were not successfully identified by PTT due to their low occurrence. However, PTT scored positive and negative predictive values of 0.803 and 0.788 for central events, respectively. Preliminary findings suggest that PTT has the potential to differentiate normal breathing from central events only in sleeping infants.

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“…Oxygen causes ventilatory depression in mature mammals [26], and may yield similar potentiation effects to those found here. However, the present study focused on the early post-natal period during which ventilatory depression may be aggravated by other sources of respiratory instability, in particular immaturity of the central chemoreceptors [27].…”

Section: Methodological Considerationsmentioning

confidence: 99%

Inhibitory effects of repeated hyperoxia on breathing in newborn mice

Lofaso¹,

Dauger²,

Matrot³

et al. 2006

European Respiratory Journal

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Brief oxygen therapy is commonly used for resuscitation at birth or prevention of hypoxaemia before procedures during the neonatal period. However, O 2 may severely depress breathing, especially when administered repeatedly. The aim of the present study was to test the effects of repeated hyperoxia on breathing control in newborn mice.A total of 97 Swiss mouse pups were assigned to O 2 or air on post-natal day 0, 1 or 2. Each pup in the O 2 group was subjected to four hyperoxic tests (100% O 2 for 3 min followed by 12 min normoxia), whereas pups in the air group were maintained in normoxia. Breathing variables were measured using flow-through barometric plethysmography.O 2 significantly decreased minute ventilation as seen in a decrease in respiratory rate. This decrease became significantly larger with repeated exposure and ranged -17--26% for all ages combined. Furthermore, hyperoxia increased total apnoea duration, as compared with the baseline value.In newborn mice, repeated hyperoxia increasingly depressed breathing. This finding further supports a need for stringent control of oxygen therapy, most notably repeated oxygen administration in the neonatal period for premature newborn infants and those carried to term.

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Delayed chemoreceptor responses in infants with apnoea

Cited by 38 publications

References 33 publications

Ventilatory Response to a Hyperoxic Test Is Related to the Frequency of Short Apneic Episodes in Late Preterm Neonates

Ventilatory Response to a Hyperoxic Test Is Related to the Frequency of Short Apneic Episodes in Late Preterm Neonates

An investigation on pulse transit time in respiratory sleep studies for infants

Inhibitory effects of repeated hyperoxia on breathing in newborn mice

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