Measurement of the CO<sub>2</sub>apneic threshold in newborn infants: possible relevance for periodic breathing and apnea

Khan, Akram; Qurashi, Mansour; Kwiatkowski, Kim; Cates, Don; Rigatto, Henrique

doi:10.1152/japplphysiol.00574.2003

Cited by 92 publications

(51 citation statements)

References 45 publications

(52 reference statements)

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“…Therefore, increased ventilatory response to hypoxia is associated with increased respiratory instability. Synergistic interactions between increased CO 2 and lowered O 2 likely contribute to destabilized breathing patterns [23] .…”

Section: Discussionmentioning

confidence: 99%

Effect of Intermittent Hypercapnia on Respiratory Control in Rat Pups

et al. 2009

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Preterm infants are subject to fluctuations in blood gas status associated with immature respiratory control. Intermittent hypoxia during early postnatal life has been shown to increase chemoreceptor sensitivity and destabilize the breathing pattern; however, intermittent hypercapnia remains poorly studied. Therefore, to test the hypothesis that intermittent hypercapnia results in altered respiratory control, we examined the effects of daily exposure to intermittent hypercapnia on the ventilatory response to subsequent hypercapnic and hypoxic exposure in neonatal rat pups. Exposure cycles consisted of 5 min of intermittent hypercapnia (5% CO₂, 21% O₂, balance N₂) followed by 10 min of normoxia. Rat pups were exposed to 18 exposure cycles each day for 1 week, from postnatal day 7 to 14. We analyzed diaphragm electromyograms (EMGs) from pups exposed to subsequent acute hypercapnic (5% CO₂) and hypoxic (12% O₂) challenges. In response to a subsequent hypercapnia challenge, there was no significant difference in the ventilatory response between control and intermittent hypercapnia-exposed groups. In contrast, intermittent hypercapnia-exposed rat pups showed an enhanced ventilatory response to hypoxic challenge with an increase in minute EMG to 118 ± 14% of baseline versus 107 ± 13% for control pups (p < 0.05). We speculate that prior hypercapnic exposure may increase peripheral chemoreceptor response to subsequent hypoxic exposures and result in perturbed neonatal respiratory control.

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Section: Discussionmentioning

confidence: 99%

Effect of Intermittent Hypercapnia on Respiratory Control in Rat Pups

et al. 2009

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“…Unlike adults, CO 2 apneic threshold is close to the baseline PCO 2 in preterm infants. 9 Hypoxia can narrow this difference further through reduced metabolism. Any transient hyperventilation event can easily precipitate apnea in these premature infants by decreasing the PCO 2 below the apneic threshold.…”

Section: Central Chemoreceptors and Impaired Hypercapnic Ventilatory mentioning

confidence: 99%

Apnea of prematurity: pathogenesis and management strategies

Mathew

2010

J Perinatol

105

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Apnea of prematurity (AOP) is a significant clinical problem manifested by an unstable respiratory rhythm reflecting the immaturity of respiratory control systems. This review will address the pathogenesis of and treatment strategies for AOP. Although the neuronal mechanisms leading to apnea are still not well understood, recent decades have provided better insight into the generation of the respiratory rhythm and its modulation in the neonate. Ventilatory responses to hypoxia and hypercarbia are impaired and inhibitory reflexes are exaggerated in the neonate. These unique vulnerabilities predispose the neonate to the development of apnea. Treatment strategies attempt to stabilize the respiratory rhythm. Caffeine remains the primary pharmacological treatment modality and is presumed to work through blockade of adenosine receptors A 1 and A 2 . Recent evidences suggest that A 2A receptors may have a greater role than previously thought. AOP typically resolves with maturation suggesting increased myelination of the brainstem.

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“…Both the hypoxemic and hypercapnic ventilator drives decrease during sleep and an apneic threshold level to CO 2 emerges that is not present during wakefulness. In infants, the CO 2 apneic threshold is approximately 1 mm Hg below eupneic breathing (51). By contrast, adults have a difference of 4 mm Hg between eupnea and the apneic threshold, leading to more stable ventilation.…”

Section: Ontogeny Of Ventilatory Controlmentioning

confidence: 96%

Obstructive Sleep Apnea in Infants

Katz

Mitchell

D’Ambrosio

2012

Am J Respir Crit Care Med

220

224

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Obstructive sleep apnea in infants has a distinctive pathophysiology, natural history, and treatment compared with that of older children and adults. Infants have both anatomical and physiological predispositions toward airway obstruction and gas exchange abnormalities; including a superiorly placed larynx, increased chest wall compliance, ventilation-perfusion mismatching, and ventilatory control instability. Congenital abnormalities of the airway, such as laryngomalacia, hemangiomas, pyriform aperture stenosis, choanal atresia, and laryngeal webs, may also have adverse effects on airway patency. Additional exacerbating factors predisposing infants toward airway collapse include neck flexion, airway secretions, gastroesophageal reflux, and sleep deprivation. Obstructive sleep apnea in infants has been associated with failure to thrive, behavioral deficits, and sudden infant death. The proper interpretation of infant polysomnography requires an understanding of normative data related to gestation and postconceptual age for apnea, arousal, and oxygenation. Direct visualization of the upper airway is an important diagnostic modality in infants with obstructive apnea. Treatment options for infant obstructive sleep apnea are predicated on the underlying etiology, including supraglottoplasty for severe laryngomalacia, mandibular distraction for micrognathia, tonsillectomy and/or adenoidectomy, choanal atresia repair, and/or treatment of gastroesophageal reflux.Keywords: sleep-disordered breathing; adenotonsillar hypertrophy; craniofacial; micrognathia; laryngomalacia Infants experience a wide range of sleep-disordered breathing patterns, including periodic breathing (1), apnea of prematurity (2), and central apnea, but little attention has been given to obstructive sleep apnea (OSA). Infants are particularly vulnerable to obstructive sleep-disordered breathing related to their upper airway structure (3), adverse pulmonary mechanics (4), ventilatory control (5), arousal threshold (6), laryngeal chemoreflex (7), and an REM-predominant sleep state distribution (8). The anatomical and physiological predispositions toward airway obstruction in infants are summarized in Table 1. Airway collapse may occur passively related to the balance between the viscoelastic properties of the pharynx, pharyngeal dilators, and the transmural pressure. Alternatively, obstructive apnea may result from active glottic closure, termed the laryngeal chemoreflex. The diagnosis of OSA in infants is confirmed by polysomnography and the etiology is often determined via direct endoscopic visualization of the airway. Infants with severe OSA will often have marked hypoxemia or sleep fragmentation, which is likely to result in considerable morbidity. As such, successful therapy is mandatory, even if this requires invasive treatment including nasopharyngeal tubes, continuous positive airway pressure (CPAP), supraglottoplasty, or even tracheostomy. This review focuses on the clinical features, polysomnographic patterns, pathogenesis, diagnosis, and mana...

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Measurement of the CO₂apneic threshold in newborn infants: possible relevance for periodic breathing and apnea

Cited by 92 publications

References 45 publications

Effect of Intermittent Hypercapnia on Respiratory Control in Rat Pups

Effect of Intermittent Hypercapnia on Respiratory Control in Rat Pups

Apnea of prematurity: pathogenesis and management strategies

Obstructive Sleep Apnea in Infants

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Measurement of the CO2apneic threshold in newborn infants: possible relevance for periodic breathing and apnea

Cited by 92 publications

References 45 publications

Effect of Intermittent Hypercapnia on Respiratory Control in Rat Pups

Effect of Intermittent Hypercapnia on Respiratory Control in Rat Pups

Apnea of prematurity: pathogenesis and management strategies

Obstructive Sleep Apnea in Infants

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Product

Resources

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Measurement of the CO₂apneic threshold in newborn infants: possible relevance for periodic breathing and apnea