APNEA OF PREMATURITY.ppt
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ea versus Gestational Age
Although there is considerable variation in incidence and severity of apnea in premature infants, both are inversely related to gestational age. Approximately 50% of infants less than 1500 grams birth weight require either pharmacologic intervention or ventilatory support for recurrent prolonged apneic episodes. The peak incidence occurs between 5 and 7 days postnatal age. Apnea of Prematurity is a specific diagnosis and usually resolves between 34 to 36 weeks postconceptual age.
APNEA OF PREMATURITY
GARRETT S. LEVIN, M.D. DEPARTMENT OF PEDIATRICS DIVISION OF NEONATOLOGY
Definition of Apnea
Apnea is the most common problem of ventilatory control in the premature infant frequently prolonging hospitalization and the need for cardiopulmonary monitoring. The standard definition of apnea is cessation of inspiratory gas flow for 20 seconds, or for a shorter period of time if accompanied by bradycardia (heart rate less than 100 beats per minute), cyanosis, or pallor.
•Abnormal or hyperactive reflexes •- likely to result in central apnea
•Head's paradoxical reflex (gasp and apnea following lung inflation) •Laryngeal receptors (taste buds) acting through superior laryngeal nerves •Posterior pharyngeal reflex (apnea induced by deep repeated suctioning) •Vascular receptors (apnea induced by large vessel distension) •Decreased or inhibitory lower afferent input to the central respiratory center •- likely to result in central apnea •Sensory receptors (temperature receptors on face) •Chemoreceptor immaturity •Hypoxemia •- likely to result in central or mixed apnea •Immature ventilatory response to hypoxemia •Presence of lung disease •Decreased lung volume •Patent ductus arteriosus •Anemia •Hypotension with decreased oxygen delivery to the brain
•Primary central respiratory center depression •- likely to result in central apnea
•Fewer neuronal synapses •Decreased carbon dioxide (CO2) sensitivity •Decreased neurotransmitter levels •Metabolic disorders •Sepsis •Suppression by drugs •Decreased or inhibitory upper afferent input to the central respiratory center •- likely to result in obstructive, central, or mixed apnea •Less cortical traffic •Sleep state, especially REM sleep •Seizures •Metabolic disorders •Sepsis •Suppression by drugs
ONSET USUALLY BY THIRD DAY OF LIFE!
The more hypoxic, the flatter the response to carbon dioxide.
Proposed Pathogenic Mechanisms of Apnea
•Primary central respiratory center depression •Decreased or inhibitory upper afferent input to the central respiratory center •Abnormal or hyperactive reflexes •Decreased or inhibitory lower afferent input to the central respiratory center •Hypoxemia
Although there is considerable variation in incidence and severity of apnea in premature infants, both are inversely related to gestational age. Approximately 50% of infants less than 1500 grams birth weight require either pharmacologic intervention or ventilatory support for recurrent prolonged apneic episodes. The peak incidence occurs between 5 and 7 days postnatal age. Apnea of Prematurity is a specific diagnosis and usually resolves between 34 to 36 weeks postconceptual age.
APNEA OF PREMATURITY
GARRETT S. LEVIN, M.D. DEPARTMENT OF PEDIATRICS DIVISION OF NEONATOLOGY
Definition of Apnea
Apnea is the most common problem of ventilatory control in the premature infant frequently prolonging hospitalization and the need for cardiopulmonary monitoring. The standard definition of apnea is cessation of inspiratory gas flow for 20 seconds, or for a shorter period of time if accompanied by bradycardia (heart rate less than 100 beats per minute), cyanosis, or pallor.
•Abnormal or hyperactive reflexes •- likely to result in central apnea
•Head's paradoxical reflex (gasp and apnea following lung inflation) •Laryngeal receptors (taste buds) acting through superior laryngeal nerves •Posterior pharyngeal reflex (apnea induced by deep repeated suctioning) •Vascular receptors (apnea induced by large vessel distension) •Decreased or inhibitory lower afferent input to the central respiratory center •- likely to result in central apnea •Sensory receptors (temperature receptors on face) •Chemoreceptor immaturity •Hypoxemia •- likely to result in central or mixed apnea •Immature ventilatory response to hypoxemia •Presence of lung disease •Decreased lung volume •Patent ductus arteriosus •Anemia •Hypotension with decreased oxygen delivery to the brain
•Primary central respiratory center depression •- likely to result in central apnea
•Fewer neuronal synapses •Decreased carbon dioxide (CO2) sensitivity •Decreased neurotransmitter levels •Metabolic disorders •Sepsis •Suppression by drugs •Decreased or inhibitory upper afferent input to the central respiratory center •- likely to result in obstructive, central, or mixed apnea •Less cortical traffic •Sleep state, especially REM sleep •Seizures •Metabolic disorders •Sepsis •Suppression by drugs
ONSET USUALLY BY THIRD DAY OF LIFE!
The more hypoxic, the flatter the response to carbon dioxide.
Proposed Pathogenic Mechanisms of Apnea
•Primary central respiratory center depression •Decreased or inhibitory upper afferent input to the central respiratory center •Abnormal or hyperactive reflexes •Decreased or inhibitory lower afferent input to the central respiratory center •Hypoxemia