Impact on hearing of routine ear suctioning at the tympanic membrane

The Loudness of Suctioning in the Ear Canal

Aim

To determine the loudness of suctioning in the ear canal with different-sized suctions and various mediums. Aural microsuctioning is commonly used in the otolaryngologist’s office setting for cerumen removal and aural toilet. We hypothesize that the intensity of the sound would increase with increasing viscosity of the medium and increasing suction diameter.

Methods

The intensity of the sound generated was measured while suctioning air, water, and yogurt on cadaveric temporal bones with size 7 and 5 Frazier suctions. This was performed with one measurer and one operator. Under otomicroscopy, the operator would suction the ear canal and the measurer would record the intensity of the sound with a sound decibel meter placed at the lateral and posterior external auditory canal. Data was collected with two separate operators and measurers to aid with inter-rater reliability.

Results

There was a total of 240 repeated observations (10 cadavers, 3 mediums, 2 suction devices; 2 investigators). The range of the maximum peak intensity ranged from 63.0 dB to 100.0 dB. The lowest peak intensity of decibels was recorded in air with the size 5 Frazier suction; and the highest measured was with the size 5 Frazier suction in yogurt. Statistically significant differences were found only in the measurements in air.

Conclusion

Our investigation found that increasing peak sound intensities were generated by increasing the viscosity of the fluid medium that was being suctioned. However, the smaller sized diameter suction actually generated louder sound intensities than the larger diameter suction with higher viscosity fluid media, but this was not statistically significant.

Sound levels with aural suctioning: Effects of suction size, canal moisture, and distance from the eardrum

OBJECTIVE

To determine sound levels resulting from aural suctioning of the external auditory canal.

METHODS

Unweighted decibels (dB) and A-weighted decibels (dBA) sound pressure level measurements were recorded using a retrotympanic microphone in cadaveric human temporal bones. Sound measurements were made with common otologic suctions, size 3, 5, and 7 French, within the external ear canal at the tympanic membrane, 5, and 10 mm from the tympanic membrane in the dry condition. In the wet condition, the ear canal was filled with fluid and completely suctioned clear to determine sound effects of suctioning liquid from the ear canal.

RESULTS

Sound levels generated from ear canal suctioning ranged from 68.3 to 97 dB and 62.6 to 95.1 dBA. Otologic suctions positioned closer to the tympanic membrane resulted in louder sound levels, but was not statistically significant (P > .05). Using larger diameter suctions generated louder dB and dBA sound levels (P < .001) and the addition of liquid in the ear canal during the suction process generated louder dB and dBA sound levels (P < .001).

CONCLUSIONS

Smaller caliber suction sizes and nonsuctioning techniques should be utilized for in-office aural toilet to reduce noise trauma and patient discomfort.

LEVEL OF EVIDENCE

5.

Modifications of Surgical Suction Tip Geometry for Flow Optimisation: Influence on Suction-Induced Noise Pollution

Introduction

Suction devices for clearing the surgical field are among the most commonly used tools of every surgeon because a better view of the surgical field is essential. Forced suction may produce disturbingly loud noise, which acts as a nonnegligible stressor. Especially, in emergency situations with heavy bleeding, this loud noise has been described as an impeding factor in the medical decision-making process. In addition, there are reports of inner ear damage in patients due to suction noises during operations in the head area. These problems have not been solved yet. The purpose of this study was to analyse flow-dependent suction noise effects of different surgical suction tips. Furthermore, we developed design improvements to these devices.

Methods

We compared five different geometries of suction tips using an in vitro standardised setup. Two commercially available standard suction tips were compared to three adapted new devices regarding their flow-dependent (10–2000 mL/min) noise emission (dB, weighting filter (A), distance 10 cm) and acoustic quality of resulting noises (Hamilton fast Fourier analysis) during active suction at the liquid-air boundary. Noise maps at different flow rates were created for all five suction devices, and the proportion of extracted air was measured. The geometries of the three custom-made suction tips (new models 1, 2, and 3) were designed considering the insights after determining the key characteristics of the two standard suction models.

Results

The geometry of a suction device tip has significant impact on its noise emission. For the standard models, the frequency spectrum at higher flow rates significantly changes to high-frequency noise patterns (>3 kHz). A number of small side holes designed to prevent tissue adhesion lead to increased levels of high-frequency noise. Due to modifications of the tip geometry in our new models, we are able to achieve a highly significant reduction of noise level at low flow rates (new model 2 vs. standard models p < 0.001) and also the acoustic quality improved. Additionally, we attain a highly significant reduction of secondary air intake (new model 2 vs. the other models p < 0.001).

Conclusion

Improving flow-relevant features of the geometry of suction heads is a suitable way to reduce noise emissions. Optimized suction tips are significantly quieter. This may help us to reduce noise-induced hearing damage in patients as well as stress of medical staff during surgery and should lead to quieter operation theatres overall. Furthermore, the turbulence reduction and reduced secondary air intake during the suction process are expected to result in protective effects on the collected blood and thus could improve the quality of autologous blood retransfusions. We are on the way to evaluate potential benefits.

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.