Microsurgery of the Ear
A 10- to 15-degree head-up tilt increases venous drainage and
decreases bleeding. The use of a volatile anesthetic helps control arterial blood
pressure. The need for deliberately induced hypotension during microsurgery on the
ear is questionable.[105]
[249]
The goal should be diminished bleeding rather than an absolutely bloodless field.
Condon[105]
concluded that even when precautions
were taken, controlled hypotension was not free of complications. In a study of
the use of controlled hypotension for ear surgery, Eltringham and coworkers[250]
found no correlation between blood pressure and quality of the operative field.
Modified hypotensive techniques based on controlled ventilation with halothane have
been reported. Multidrug combinations of nitroglycerin, hydralazine, propranolol,
droperidol, and others can lead to excessive hypotension in which rapid reversal
is not possible. Satisfactory conditions can be provided by placing the patient
in a 15-degree head-up position, maintaining systolic blood pressure at approximately
85 mm Hg, using controlled ventilation with a volatile gas, and adding narcotic and
local infiltration or topical application of epinephrine, if necessary.
In summary, general anesthesia with a volatile anesthetic is the
first choice for microsurgery on the ear. No muscle relaxation is required. Identification
of the facial nerve is not impeded, and relative hypotension can easily be maintained.
Middle Ear Surgery: Nausea and Vomiting
Procedures on the middle ear are likely to cause postoperative
emesis (see Chapter 68
),
and PONV can undo the results of the delicate middle ear reconstruction. Many regimens
have been shown to be effective, including propofol infusion,[251]
granisetron,[252]
transdermal scopolamine,[253]
ondansetron,[254]
droperidol, and elimination of
N2
O.[175]
[255]
Splinter and colleagues[256]
were unable to demonstrate
that N2
O induces vomiting in children after myringotomy. PONV may be
controlled with intravenous doses of a potent antiemetic drug (e.g., droperidol,
0.01mg/kg; ondansetron, 0.05 mg/kg; or dolasetron, 0.20 mg/kg) given during surgery.
Myringotomy
Bilateral myringotomy with tube placement is the second most frequently
performed pediatric surgical procedure.[256]
[257]
Some form of analgesia is required in most children after this brief outpatient
procedure.[258]
Derkay and associates[257]
found that when intraoperative eardrops mixed with 4% lidocaine were used, the preoperative
oral analgesics were of little added benefit. Preoperative oral acetaminophen[259]
or acetaminophen with codeine[258]
has been recommended
as effective.
