Measurement of the sound intensity during suction of middle-ear fluid following myringotomy.

OBJECTIVE

To determine noise intensity during middle-ear aspiration in order to evaluate whether levels can be potentially harmful.

METHODS

In this prospective, observational study, middle-ear effusion was aspirated following myringotomy using a suction instrument with a probe tube microphone. Sound pressure levels and duration were measured, and frequency domain analysis was performed.

RESULTS

Forty-four ears were analysed, consisting of 20 with mucoid effusion, 11 with serous effusion and 13 with no effusion. Maximum peak sound intensity ranged from 84 to 157 dB. Half of the ears (50 per cent) were exposed to greater than 140 dB; of these, 82 per cent were exposed for longer than 0.2 ms (range, 0.05-14 ms). There was no significant difference in sound pressure level between ears with mucoid and serous effusion; however, ears with mucoid effusion required longer suction times (p < 0.0030). In addition, peak intensity was greater for ears with mucoid effusion versus those with serous or no effusion (p < 0.0001).

CONCLUSION

Middle-ear aspiration during myringotomy caused noise levels within a potentially harmful range.