Cochlear Implant

Anesthesia Implications

Position: Supine, arms tucked, Bed turned 180 degrees
Time: 2-4 hours (long)
Blood Loss: Low (10-50 ml)
Post-op Pain: Moderate (3-6)
Maintenance Paralytic: Ask surgeon
Lead: Yes

Preoperative Period – Procedures involving the middle ear commonly cause PONV. Sharing this information with the patient can be helpful, as it prepares them for what to expect postoperatively.

Anesthetic Approach – The bed will be turned 180 degrees and the face will be draped so airway access is VERY limited. For this reason, GETT is the most common choice for this procedure. GETT is also helpful to completely immobilize the patient to reduce/eliminate movement when the surgeon uses the operating microscope. The choice to use TIVA (eg. remifentanil + propofol), IV + Gas (dirty TIVA), or only a full MAC of gas is at the discretion of the anesthesia provider. Literature and practice guidelines vary.

Paralytic – Ask surgeon. They typically do not want any long acting paralytics. Usually succinylcholine is the induction agent of choice.

Nitrous oxide – not typically utilized in these cases as it can increase the risk of PONV and cause pressure changes in the middle ear.

Nerve Integrity Monitoring System (NIMS) – facial nerve monitoring is commonly utilized for many otologic procedures. This is because the facial nerve passes through the inner ear and is at risk for injury. Long-acting paralytics have the potential to interfere with nerve monitoring, which is why they should not be utilized for this type of procedure (but ask the surgeon).

PONV Prophylaxis – Most surgeons request high dose Decadron (10mg in adults, unless contraindicated). Zofran (4 mg) either at the beginning of the case, or within 30-60 minutes of the case ending.

Tucked Arms (general considerations): Consider a second IV – once the procedure has started, it’s going to be VERY difficult to handle IV issues – especially if your only IV has problems. Ensure the IV is running and monitors are still functioning after tucking the patient’s arms

180 degree turns (general considerations): Arrange lines and monitor cords in anticipation to turn. If turning right, keep cords and lines draped to the left. If turning left, keep cords and lines draped to the right. Have a circuit extension connected. Disconnect the circuit when turning and immediately reconnect.

Long procedure (general considerations): Procedures anticipated to last longer than 2 hours generally require a urinary catheter. Also consider checking lines and positioning regularly as the risks of infiltration and nerve damage are increased with procedure time. Consider an IV fluid warmer and a forced air warmer to keep the patient euthermic.

Fluoroscopy / Xray (general considerations): Have lead aprons and thyroid shields available. Alternatively, distancing yourself 3 to 6 feet will reduce scatter radiation to 0.1% to 0.025% respectively. Occupational maximum exposure to radiation should be limited to a maximum average of 20 Sv (joules per kilogram – otherwise known as the Sievert/Sv) per year over a 5 year period. Limits should never exceed 50 Sv in a single year.

Patients receiving a cochlear implant device typically have severe sensorineural hearing loss. The purpose of the implant is to improve hearing function via bypassing the dysfunctional inner ear.

A postauricular incision and mastoidectomy will be performed on the affected ear. The surgeon then utilizes a microscope to thread an electrode into the inner ear (cochlea). The implant processor and electrode leads are secured under the skin behind the ear.

Intraoperative C arm fluoroscopy is typically utilized at the end of the procedure to confirm placement.