Sizing Up Surgery
Bispectral Index (BIS)
The BIS monitoring system was first cleared
by FDA in October 1996 to monitor the state of the brain in the intensive-care
unit, the operating room, and for clinical research. The system, which includes
an enhanced electroencephalogram (EEG) monitor, analyzes a patient's brain wave
pattern and converts it into a "depth of sedation" number between 0
(indicating no brain activity) and 100 (fully awake).
It's a popular belief that anesthesiologists
use the device to reduce or prevent "awareness" during surgery. But
FDA's Center for Devices and Radiological Health says the device has not been
approved or labeled for monitoring to reduce awareness. It is intended only to
monitor the state of the brain.
FDA initially approved the scopolamine patch,
distributed under the brand name Transderm Scop by Novartis Consumer Health in
New Jersey and manufactured by ALZA Corporation of Palo Alto, CA, in December
1979 as a prescription drug to prevent nausea and vomiting associated with
motion sickness. Following the manufacturer's removal of the product from the
marketplace in 1994 due to manufacturing problems, FDA approved the drug again
on Oct. 27, 1997, for the additional indication of preventing nausea and
vomiting during or after surgery.
The small, Band-Aid-like patch is placed
behind the ear the night before surgery, or an hour before a Caesarean section.
The medication in the patch goes through the skin directly into the
bloodstream. It is not to be worn for more than three days, and is intended for
a single use only.
Approved by FDA in July 1996, remifentanil,
marketed as Ultiva and manufactured by Glaxo Wellcome of North Carolina, is an
analgesic for inducing and maintaining general anesthesia for surgery. It
safely breaks down in the bloodstream and body tissues within minutes. Unlike
other drugs that must be metabolized or broken down by the liver and kidneys,
remifentanil gets broken down by enzymes in the blood and muscles. This means
that the drug has a half-life of three to six minutes in the body, compared to
90 minutes or more for other drugs. That, in turn, results in the patient
waking up and having the breathing tube removed considerably sooner.