TY - JOUR
T1 - An animal model for assessment of amniotic fluid clearance from the middle ear
AU - Perez, Ronen
AU - Priner, Ronit
AU - Cohen, David
AU - Freeman, Sharon
AU - Sohmer, Haim
PY - 2002
Y1 - 2002
N2 - Hypothesis: To determine the time needed for clearance of amniotic fluid from the middle ear after birth, an animal model study was performed. Background: Before birth, the middle ear is full of amniotic fluid, and there is controversy about the time it takes for it to clear postnatally. This is of importance because it is suspected that amniotic fluid in the middle ear of the newborn may affect results of screening of hearing when using otoacoustic emissions. Methods: Adult and neonatal guinea pigs underwent a rightside cochleotomy followed by baseline otoscopy, tympanometry, and auditory nerve- and brainstem-evoked response (ABR) measurements of the left ear. Subsequently, the animals' left middle ears were filled with saline through a hole drilled in the bulla. Over the next few days, assessment of saline clearance was conducted by repeated left-side otoscopy, tympanometry, and measurement of ABR. Results: After filling the middle ear with saline, the tympanic membrane was opaque, a type B tympanogram was obtained, and the ABR threshold was elevated. After an average of 6.3 ± 3.0 days, air bubbles were seen in otoscopy, a type C tympanogram was obtained, and the ABR threshold improved. Finally, after an average of 9.5 ± 2.7 days, all 3 parameters returned to their baseline values. Conclusion: Taking into consideration that this is an animal study, the results suggest that clearance of amniotic fluid from the newborn middle ear takes longer than has been generally thought. In addition, an animal model for assessing the clearance of fluid from the middle ear has been developed.
AB - Hypothesis: To determine the time needed for clearance of amniotic fluid from the middle ear after birth, an animal model study was performed. Background: Before birth, the middle ear is full of amniotic fluid, and there is controversy about the time it takes for it to clear postnatally. This is of importance because it is suspected that amniotic fluid in the middle ear of the newborn may affect results of screening of hearing when using otoacoustic emissions. Methods: Adult and neonatal guinea pigs underwent a rightside cochleotomy followed by baseline otoscopy, tympanometry, and auditory nerve- and brainstem-evoked response (ABR) measurements of the left ear. Subsequently, the animals' left middle ears were filled with saline through a hole drilled in the bulla. Over the next few days, assessment of saline clearance was conducted by repeated left-side otoscopy, tympanometry, and measurement of ABR. Results: After filling the middle ear with saline, the tympanic membrane was opaque, a type B tympanogram was obtained, and the ABR threshold was elevated. After an average of 6.3 ± 3.0 days, air bubbles were seen in otoscopy, a type C tympanogram was obtained, and the ABR threshold improved. Finally, after an average of 9.5 ± 2.7 days, all 3 parameters returned to their baseline values. Conclusion: Taking into consideration that this is an animal study, the results suggest that clearance of amniotic fluid from the newborn middle ear takes longer than has been generally thought. In addition, an animal model for assessing the clearance of fluid from the middle ear has been developed.
KW - Amniotic fluid
KW - Auditory brainstem response
KW - Middle ear
KW - Neonate
KW - Otoscopy
KW - Tympanometry
UR - http://www.scopus.com/inward/record.url?scp=0036147477&partnerID=8YFLogxK
U2 - 10.1097/00129492-200201000-00008
DO - 10.1097/00129492-200201000-00008
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C2 - 11773842
AN - SCOPUS:0036147477
SN - 1531-7129
VL - 23
SP - 29
EP - 33
JO - Otology and Neurotology
JF - Otology and Neurotology
IS - 1
ER -