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Changes in resistance and ventilatory timing that accompany apnea in premature infants.
Miller, M J; Petrie, T G; Difiore, J M.
Afiliação
  • Miller MJ; Department of Pediatric and Medicine, Rainbow Babies and Childrens Hospital, Case Western Reserve University, Cleveland, Ohio 44106.
J Appl Physiol (1985) ; 75(2): 720-3, 1993 Aug.
Article em En | MEDLINE | ID: mdl-8226474
To characterize the changes in respiratory mechanics and ventilatory timing that accompany apnea in premature infants, we evaluated 36 apneas in 13 premature infants (birth weight, 1,200 +/- 350 g, postconceptional age at study 34 +/- 3 wk). Apnea was defined as a ventilatory pause > or = 10s accompanied by a decrease in heart rate of 20 beats/min. Nasal airflow was recorded with a pneumotachometer, and esophageal, pharyngeal, and nasal mask pressures were continuously measured. Inspiratory time (TI), expiratory time (TE), tidal volume (VT), and VT/TI were determined over five breaths before and after apnea. In addition, total pulmonary resistance (RT) and supraglottic resistance (Rs) were measured over the same epochs in inspiration and expiration. Before apnea, TE and RT increased (P < 0.05 and < 0.01, respectively); however, Rs did not change. Immediately after apnea, prolongation of TI occurred and both RT and Rs were increased (P < 0.01), consistent with continued upper airway instability. However, within two breaths after resolution of the apnea, RT and Rs returned to normal, reflecting rapid recovery of upper airway and total pulmonary resistance. The ventilatory changes that precede and follow apnea closely resemble those occurring during periodic breathing.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Apneia / Recém-Nascido Prematuro / Mecânica Respiratória / Resistência das Vias Respiratórias Limite: Humans / Newborn Idioma: En Revista: J Appl Physiol (1985) Assunto da revista: FISIOLOGIA Ano de publicação: 1993 Tipo de documento: Article País de publicação: Estados Unidos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Apneia / Recém-Nascido Prematuro / Mecânica Respiratória / Resistência das Vias Respiratórias Limite: Humans / Newborn Idioma: En Revista: J Appl Physiol (1985) Assunto da revista: FISIOLOGIA Ano de publicação: 1993 Tipo de documento: Article País de publicação: Estados Unidos