title: Unusual respiratory response to oxygen in an infant with repetitive cyanotic episodes.
abstract: High inspired oxygen concentrations have recently been recommended to control Cheyne-Stokes respiration in adults, with the intention of averting periodic apnea and its attendant arterial desaturation. We report a case study on an infant presenting with recurrent apnea and cyanosis in which oxygen treatment led to a gross form of respiratory instability we call episodic breathing, in which a breathing phase of 60 to 90 s alternated with an apnea lasting up to 60 s. When oxygen was discontinued, a profound arterial desaturation developed before breathing recommenced and restored oxygen levels. We propose that episodic breathing is an unusual respiratory pattern that involves the central chemoreceptors and results from the ventilatory threshold (the central PCO(2) at which breathing starts) lying considerably above the apneic threshold (the central PCO(2 )at which breathing stops). This feature predisposes to lengthy periods of hyperpnea alternating with lengthy periods of apnea. We suggest that when the case infant returned to air during episodic breathing, termination of apnea was entirely dependent upon carotid body activity, which reached a sufficient level to restart breathing only when arterial desaturation was severe. We conclude that oxygen therapy involves potential risks when employed to treat respiratory disorders involving unstable breathing patterns in the infant.
authors.affiliation: Ritchie Centre for Baby Health Research, Institute of Reproduction and Development, Monash Medical Centre, Clayton, Victoria, Australia. philip.berger@med.monash.edu.au
authors.forename: P J
authors.initials: PJ
authors.lastname: Berger
authors.forename: E M
authors.initials: EM
authors.lastname: Skuza
authors.forename: V
authors.initials: V
authors.lastname: Brodecky
authors.forename: S M
authors.initials: SM
authors.lastname: Cranage
authors.forename: T M
authors.initials: TM
authors.lastname: Adamson
authors.forename: M H
authors.initials: MH
authors.lastname: Wilkinson
mesh_terms: D000328:Adult; D000818:Animals; D002344:Carotid Body / Q000503:physiopathology; D002628:Chemoreceptor Cells / Q000503:physiopathology; D002639:Cheyne-Stokes Respiration / Q000503:physiopathology; D003490:Cyanosis / Q000503:physiopathology*; D004195:Disease Models, Animal; D004200:Diseases in Twins; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D010100:Oxygen / Q000097:blood; D010102:Oxygen Inhalation Therapy; D017286:Polysomnography; D012125:Respiratory Center / Q000503:physiopathology; D012756:Sheep; D020182:Sleep Apnea, Central / Q000503:physiopathology*
chemical_list: D010100:Oxygen