Home' Trinidad and Tobago Guardian : December 1st 2014 Contents "I was awake but paralysed," says
Carol Weihrer as she recalls under-
going eye surgery in 1998.
"I could hear the surgeon telling his
trainee to cut deeper into the eye, "
she says. "I was screaming, but no one
could hear me. I felt no pain, just a
tugging sensation. I tried to move my
toes or even push myself off the oper-
ating table, but I couldn t move. I
thought I was dying."
The Reston, Virginia, resident inad-
vertently woke up during surgery, an
infrequent phenomenon called "acci-
dental awareness during general anes-
thesia." She s been struggling with
post-traumatic stress disorder ever
"I ve had to sleep in a recliner for
the last 16 years," Weihrer says. "If I
lie flat, I get flashbacks of the operating
table and I start violently thrashing."
Fortunately, anaesthetic awareness
is rare. But new research is shedding
light onto risk factors and the devas-
tating psychological effects the phe-
nomenon can have on patients who
experience it, especially those who are
awake and paralysed.
According to the largest study of its
kind recently published in the journal
Anaesthesia---in which researchers sur-
veyed more than three million patients
who received general anesthesia in the
United Kingdom and Ireland---roughly
one in 19,600 patients "accidentally"
wakes up during surgery.
Previous studies in the United States
reported a far higher rate of one in
1,000 surgical patients. However, cases
of anaesthetic awareness in the new
study were reported voluntarily by
patients, which could misrepresent the
Researchers did find that certain
surgeries requiring "lighter" anesthesia,
like emergency C-sections, carried a
higher risk---a rate of one in 670.
Most incidents of anaesthetic
awareness occurred among patients
who had received paralytics as part of
their anaesthetic cocktail---presumably
since they couldn t move to alert doc-
tors to the fact they were regaining
Contrary to folklore, awareness was
most likely to occur when patients
were being put to sleep before surgery
started or after the surgery had ended---
not when the surgeon was actually
Patients described a range of sen-
sations, including choking, paralysis,
pain, hallucinations, and near-death
experiences. Most episodes were short-
lived, with 75 per cent of them lasting
under five minutes.
Despite this, nearly half of all patients
who were conscious during surgery
had long-term psychological conse-
quences such as PTSD and depres-
Among the symptoms experienced
during the event, paralysis was the
most distressing to patients---more so
than pain, says professor Jaideep Pan-
dit, consultant anesthetist at Oxford
University Hospitals and lead author
of the study.
"Paralysis is terrifying and has never
been experienced by most people,"
In the United States, more than 21
million patients receive general anes-
Experts estimate that roughly
26,000 of these patients experience
anaesthetic awareness. Even if we
applied the relatively low rate found
in this new study, at least 1,000 Amer-
icans each year would still wake up
And "even one is too many," says
Dr Daniel Cole, vice president of the
American Society of Anesthesiologists.
General anesthesia involves a drug
concoction that renders you uncon-
scious, takes away your pain, and
induces amnesia. A paralytic is often
added to ease the insertion of a breath-
ing tube, prevent patients from moving,
and allow surgeons to operate in areas
that are inaccessible when muscles are
Anaesthetic awareness occurs when
the amount of anesthesia is insufficient
to suppress human consciousness, Cole
says. And certain surgeries---where
lower doses of anesthesia are required---
carry a higher risk.
Emergency C-sections, for instance,
necessitate lower doses of anaesthetic
to prevent harm to the baby. Lower
doses are required, also, during cardiac
and emergency trauma surgeries, since
large doses could push these medical-
ly-fragile patients over the edge, Cole
But anaesthetic awareness really
becomes an issue when paralytics are
used, Pandit says, since patients can t
move to let doctors know they re
Doctors must instead rely on subtle,
often unreliable, methods of monitor-
For instance, increases in heart rate
and blood pressure may signal to doc-
tors that a patient is stressed and pos-
sibly awake. But drugs given before or
during the operation could block the
body s stress response.
Also, though doctors continuously
measure the level of anaesthetic gas
in patient s lungs to ensure appropriate
dosage, the gas may affect each person
differently, Pandit says.
Brain monitors, which track electrical
activity in the brain, have been touted
as a potential solution to the problem.
Doctors can use the monitors to keep
brain activity below a certain threshold
during surgery. But some studies have
shown a benefit, while others have
shown no reduction in the rate of
anaesthetic awareness when brain
monitors are used, Pandit says.
This uncertainty has prevented the
widespread implementation of brain
monitors across the United States and
has led the ASA to recommend that
the monitors only be used on a case-
by-case basis in high-risk patients.
Without foolproof methods of
assessing consciousness in paralysed
patients, it s inevitable that some cases
of anaesthetic awareness are only
recognised after surgery---once the
patient can communicate what hap-
body & soul
Guardian www.guardian.co.tt Monday, December 1, 2014
YOUR DAILY HEALTH
News and advice
Anaesthetic awareness---a terrifying possibility
Still, more can be done to pre-
vent anaesthetic awareness, says
Nerve stimulators, which meas-
ure the extent of paralysis, should
be used throughout surgery to
ensure that doctors only use the
minimum amount of paralytic
required, Pandit says.
This would still give patients
the ability to move if they started
to wake up.
Also, educating patients about
anaesthetic awareness prior to
surgery is crucial, says Pandit.
"Patients who were told about
awareness before surgery were
prepared and not distressed when
they experienced it," he says.
Cole recommends that doctors
discuss the possibility of aware-
ness only with patients who are
at high risk or when patients
themselves raise questions about
There s a concerted effort to
educate doctors as well. Education
about anaesthetic awareness is a
mandatory part of residency train-
ing, board certification, and annual
meetings, Cole says.
The ASA also maintains a data-
base of all awareness cases to allow
doctors to better understand what
went wrong. (cnn.com)
Roughly one in 19,000 patients "accidentally" wakes up during surgery.
And the long-term effects can be quite damaging.
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