Investigation/conclusion: a female patient had a lumbar mri examination and after this she claimed to suffer from hearing loss.She did indicate that she already experienced tinnitus before the examination.An analysis was done to determine the sound levels created by the system during the examination.The analysis showed that the noise level of the examination (extrapolated to a 1 hour examination) was 101.4 dba.The philips headset provided to the patient offers damping of 20 db in the 1 khz range.The patient refused to use the additionally provided earplugs.We therefore calculate with 20 db damping from the provided headset.The attenuated noise level is (101.4 dba.¿ 20 db) = 81.4 dba.This is below the limit of 99 dba as formulated in the iec60601-2-33 standard.There is no evidence that the alleged hearing loss is related to the mr examination.It is known that the acoustic noise level of an mr system may be high enough to cause discomfort or result in temporary or even permanent loss of hearing when no adequate hearing protection is applied.The acoustic noise level of an mr system can also be one of the precipitating factors for the onset of tinnitus.Philips mr scanners fulfill the requirements as formulated in the iec60601-2-33 standard with respect to the allowed maximum acoustic noise production and are designed to be significantly quieter than the level set in this standard.Adequate hearing protection is necessary to prevent hearing complaints.The minimum level of protection is prescribed in the instructions for use (ifu): ensure to use acoustic damping of 30db or better.The ifu also states the special attention must be paid to patients to whom the headset or earplugs cannot be applied adequately.Furthermore, it stated that the operator should be trained to fit the earplugs properly.During all scans with a spl > 0 (as displayed on the info page), hearing protection must be used to comply with the requirements as formulated in the iec60601-2-33 standard.As most examinations do contain scans with a spl>0, hearing protection must be provided to all patients to prevent discomfort, temporary or even permanent loss of hearing.
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