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document
Why the prone position is a risk factor for sudden infant death syndrome . INTRODUCTION The laryngeal chemoreflex may explain why prone sleeping increases the risk of sudden infant death syndrome ( SIDS ) . Swallowing and arousal are crucial to prevent laryngeal chemoreflex stimulation . Our aim was to examine these reflexes and breathing responses in healthy neonates after pharyngeal infusion of water in the supine versus the prone position , controlling for sleep state . METHODS A total of 10 term infants were recruited after parental consent and ethics approval . Polygraphic recordings included sleep state ( active and quiet sleep by electroencephalogram , eye movements , breathing , and behavior ) , cardiorespiratory measurements ( nasal airflow , chest wall movements , heart rate , and oxygen saturation ) , swallowing , and esophageal activity ( solid state pressure catheter ) . Initial sleeping position was assigned randomly . Measurements were made for 1 minute before and after 0.4 mL of water was instilled into the oropharynx . To detect a 30 % decrease in swallowing , power analysis indicated that > /=10 babies were required . Analysis , blinded to position , was made using nonparametric statistics . RESULTS Of the 164 infusions , the most commonly evoked airway protective responses to pharyngeal infusion were swallowing ( 95 % ) and arousal ( 54 % ) . After infusion in active sleep , there was a significant reduction in swallowing and breathing when the prone position was compared with the supine position ( prone : 21.3 [ 1.0 ] swallows/min and -9.6 [ 2.1 ] breaths/min ; and supine : 32 ( 2.2 ) and -2 . 9 ( 1.5 ) , respectively ) . However , there was no difference in the occurrence of arousal after water infusion . CONCLUSION These data suggest that airway protection is compromised in the prone sleeping position during active sleep , even in healthy infants exposed to minute pharyngeal fluid volumes of 0.4 mL . This is because swallowing rate is reduced significantly , and there is no compensatory increase in arousal . The reduction in airway protective reflexes when in the prone position and in active sleep may be the mechanism for the increased risk of SIDS in the prone position .
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Intervention_Physical
prone position
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Intervention_Physical
Initial sleeping position was assigned randomly
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Intervention_Physical
1 minute before and after 0.4 mL of water was instilled into the oropharynx
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Outcome_Physical
reflexes and breathing responses
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Outcome_Physical
sleep state ( active and quiet sleep by electroencephalogram , eye movements , breathing , and
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Outcome_Mental
behavior
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Outcome_Physical
) , cardiorespiratory measurements ( nasal airflow , chest wall movements , heart rate , and oxygen saturation ) , swallowing , and esophageal activity ( solid state pressure catheter )
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Outcome_Physical
swallowing
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Outcome_Physical
swallowing
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Outcome_Physical
arousal
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Outcome_Physical
swallowing and breathing
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Outcome_Physical
swallows/min
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Outcome_Physical
breaths/min
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Outcome_Physical
arousal
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Outcome_Physical
swallowing rate
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Outcome_Physical
arousal
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Outcome_Physical
airway protective reflexes
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Participant_Condition
healthy
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Participant_Age
neonates
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Participant_Sample-size
10
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Participant_Age
infants