Effect of anaesthetic agents on tympanometry and middle-ear effusions.
Following informed parental consent 93 children underwent bilateral grommet insertion. Tympanometry was performed pre-operatively, and immediately prior to myringotomy. A standardized anaesthetic was used. At myringotomy the presence or absence of fluid was recorded, as well as the time since induction of the general anaesthetic. A pre-operative type B tympanogram predicted a middle-ear effusion at myringotomy in 92 per cent of patients. A pre-operative type C2 tympanogram predicted a middle-ear effusion at myringotomy in 39 per cent of patients. Sixty tympanograms (30 per cent) changed following a general anaesthetic. Fourteen type B tympanograms changed to type A and eight of these had effusions. The duration of the general anaesthetic did not influence the probability of a middle-ear effusion being present at myringotomy. A pre-operative type B tympanogram is a good predictor of middle-ear fluid. The duration of the general anaesthetic is not significant in predicting the presence of a middle-ear effusion.
Department of Otorhinolaryngology/Head and Neck Surgery, Leicester Royal Infirmary, UK.
B M
BM
Fish
A R
AR
Banerjee
C R
CR
Jennings
I
I
Frain
A A
AA
Narula
D000158:Acoustic Impedance Tests / Q000592:standards*; D000768:Anesthesia, General / Q000009:adverse effects; D018681:Anesthetics, General / Q000008:administration & dosage / Q000009:adverse effects*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D009609:Nitrous Oxide / Q000008:administration & dosage / Q000009:adverse effects*; D010034:Otitis Media with Effusion / Q000175:diagnosis*; D011446:Prospective Studies
D018681:Anesthetics, General; D009609:Nitrous Oxide