Influence of hypothermia and extracorporeal circulation on transiently evoked otoacoustic emission (TEOAE) in children operated on for various heart defects (I)

The aim of this study was to determine influence of extracorporeal circulation and body temperature on transiently evoked otoacoustic emission (TEOAE) in children operated on for various heart defects. The investigated group consisted of 44 children (average age 9.3 +/- 5.9 years). TEOAEs were measured one day before and 7-8 days following surgery. Statistical analysis revealed the influence of duration of extracorporeal circulation and depth of hypothermia on TEOAEs assessed following surgery. TEOAEs showed tendency to decrease in patients who were operated in long lasting extracorporeal circulation in normothermia. Such a tendency was not observed in patients operated in temperatures between 30-35 degrees C and extracorporeal circulation time between 1-2 hours. This observation confirms that hypothermia has a protective role for the cochlea and could prevent its damage during long lasting operations performed in extracorporeal circulation.