Measurement of middle ear pressure changes during balloon eustachian tuboplasty: a pilot study

Transient asystole during balloon dilation of the Eustachian tube: A case report

RATIONALE

Neurally mediated reflexes can induce cardiac arrest during head and neck surgery through mechanisms including direct vagal stimulation, trigeminocardiac reflex, and baroreceptor reflex. Balloon dilation of the Eustachian tube (BDET) is a safe procedure without serious complications, including cardiac arrest.

PATIENT CONCERNS

Transient asystole developed during BDET under general anesthesia in a 33-year-old woman as soon as the balloon in the Eustachian tube (ET) was inflated.

DIAGNOSES

Monitoring records were reviewed. The asystolic period was recorded on the patient monitor as an event, which we recalled and printed. The asystole lasted for 13 seconds.

INTERVENTIONS

The patient recovered sinus rhythm spontaneously after the balloon was deflated before resuscitation. The BDET was successfully performed after prophylaxis with vagolytic drugs.

OUTCOMES

The patient recovered uneventfully after anesthesia.

LESSONS

BDET, previously known to be a relatively safe procedure, induces asystole via balloon dilation. It is thought to be a neurally mediated vagal reflex, and both anesthesiologists and otologic physicians should pay proper attention to monitoring during the procedure.

Perilymph Fistula as a Complication of Eustachian Tube Dilation and Tympanoplasty

Eustachian tube dilation (ETD) is an established, minimally invasive therapeutic approach for chronic eustachian tube dysfunction. The complications associated with performing a ETD are rare. A 22-year-old female patient presented with chronic otitis media on the right side and chronic obstructive tube dilation disorder on both sides. A type I tympanoplasty was performed on the right side because of a tympanic membrane perforation after a ETD on both sides without apparent complications. On the 5th postoperative day, she presented with headache, dizziness and hearing loss on the right side. There was a decrease of hearing threshold on the right side in the pure-tone audiogram and vHIT, cVEMP, and SVV were irregular. The β-2-transferrin test was positive. Since a right-sided perilymph fistula was suspected, an emergency tympanotomy was performed with a round window membrane cover with fascia on the right side. Intraoperatively, a regular, intact ossicular chain was found with a slightly moist middle ear mucosa. The round window membrane was covered by the promontorial lip. Under these measures, the patient’s dizziness regressed. The right ear pure-tone threshold vHIT, cVEMP, and SVV normalized.

In vivo study measuring middle ear pressure during various stages of Eustachian tube balloon dilation

OBJECTIVE

Documentation of middle ear pressure at different stages of balloon Eustachian tuboplasty and assessing risk of barotrauma with this procedure.

MAIN OUTCOME MEASURES

Middle ear pressure measurements in patients undergoing balloon Eustachian tuboplasty at the time of pre-insertion, catheter insertion, inflation, one minute post inflation, deflation, and catheter withdrawal, as well as documentation of pressure change in the middle ear between different stages.

RESULTS

A total of 24 patients and 45 Eustachian tubes, 11 females and 13 males, with an average age of 55.6 years were included in this study. Middle ear pressure values during the active stages of the procedure varied from -356 to +159 daPa. The overall greatest negative pressure change measured was -515 daPa from catheter insertion to immediately post balloon inflation. The overall greatest positive pressure change measured was +418 daPa from immediate catheter inflation to one minute post inflation.

CONCLUSIONS

There was no consistent pattern of middle ear pressure change noted during the different stages of balloon Eustachian tuboplasty as both positive and negative middle ear pressure changes were noted at the time of balloon dilation. Dangerous levels of middle ear pressure raising concern for barotrauma were not identified during the procedure.

LEVEL OF EVIDENCE

Level IV.

Multi-scale modeling of an upper respiratory airway: Effect of mucosal adhesion on Eustachian tube function in young children

BACKGROUND

The Eustachian tube is a collapsible upper respiratory airway that is periodically opened to maintain a healthy middle ear. Young children, <10 years old, exhibit reduced Eustachian tube opening efficiency and are at risk for developing middle ear infections. Although these infections increase mucosal adhesion, it is not known how adhesion forces alters the biomechanics of Eustachian tube opening in young children. This study uses computational techniques to investigate how increased mucosal adhesion alters Eustachian tube function in young children.

METHODS

Multi-scale finite element models were used to simulate the muscle-assisted opening of the Eustachian tube in healthy adults and young children. Airflow during opening was quantified as a function of adhesion strength, muscle forces and tissue mechanics.

FINDINGS

Although Eustachian tube function was sensitive to increased mucosal adhesion in both adults and children, young children developed Eustachian tube dysfunction at significantly lower values of mucosal adhesion. Specifically, the critical adhesion value was 2 orders of magnitude lower in young children as compared to healthy adults. Although increased adhesion did not alter the sensitivity of Eustachian tube function to tensor and levator veli palatini muscles forces, increased adhesion in young children did reduced the sensitivity of Eustachian tube function to changes in cartilage and mucosal tissue stiffness.

INTERPRETATIONS

These results indicate that increased mucosal adhesion can significantly alter the biomechanical mechanisms of Eustachian tube function in young children and that clinical assessment of adhesion levels may be important in therapy selection.

In Vivo Measurement of Middle Ear Pressure Changes during Balloon Eustachian Tuboplasty

Background

Balloon Eustachian tuboplasty (BET) is known as a treatment for chronic obstructive Eustachian tube dysfunction (OETD). The precise mechanism of action is not fully understood. Observations in sheep cadavers and human cadavers have shown specific middle ear pressure changes related to BET.

Methods

In this prospective study using a microfibre optical pressure sensor, pressure changes during BET were for the first time monitored transtympanically in five normal human middle ears in vivo.

Results

Middle ear pressure changes during 21 BETs consisted of five stages (insertion, inflation, deflation, withdrawal, and recovery). The highest pressure change occurred in most of the cases during the withdrawal of the balloon catheter. Withdrawal pressure yielded a mean middle ear pressure of 4.76 mmHg (61.89 daPa) with a maximum of 13.88 mmHg (179.55 daPa). Pressure amplitudes capable of causing barotrauma to ear structures were not detected. Internal carotid artery dehiscences were detected as causative of sinusidual pressure changes.

Conclusion

The middle ear pressure changes detected in vivo during BET can be attributed to the balloon inflation. Further human studies with patients affected by OETD are necessary to gain more insight into the mechanism of action of BET to clarify a possible pressure related second mechanism of action of BET.