Wednesday, November 19, 2008

Waking Up in a Surgery, Paralysed

Yesterday I came across this article titled "Awake During Surgery" in MX during my ride home. A 24-year-old patient in Northern Territory of Australia woke up during gall bladder surgery, felt every single cut by the surgeon, but couldn't do anything because she was totally paralysed.

Read the news below.

Woman wakes up during surgery
12:00 AEST Tue Nov 18 2008
By ninemsn staff

A Northern Territory woman has endured a nightmare operation at Alice Springs Hospital after she became conscious during stomach surgery but remained paralysed by the anaesthetic.

Rebecca Jones, 24, told the Northern Territory News she could feel every cut of the surgeon's knife during the operation last month but was unable to scream for help as the anaesthesia had paralysed her.

Ms Jones, who was being operated on for gallstones, said she could not open her eyes but could hear and feel everything.

"I thought the doctors had woken me up because the surgery was over — I quickly realised that was not the case," she was quoted by the Northern Territory News as saying.

Ms Jones realised her predicament when she took a breath and found she couldn’t move, but eventually moved her hand to get the attention of surgery staff — to no avail.

"(Someone) said, 'she's just moved her hand' but they kept going," she said.

The hospital's general manager Vicki Taylor admitted to the NT News that Ms Jones had been awake during the operation but denied medical staff knew of her pain.

Ms Jones is now considering legal action against the hospital.
Awareness during anaesthesia may sound like the worst nightmare to most people. Just imagine this. You are helplessly wired up like a spaceman outside a theatre, wheeled into the threatre full of fear of the unknown. Within minutes, the anaesthetist injects some anaesthetic agents into your body, and soon you drift into unconsciousness. Some time later, while you slowly return from the oblivion of anaesthesia, instead of having someone tell you "the operation was successful" like what you see in drama, you actually feel the surgeon cranking and churning your stomach and the anaesthetists discussing today's Sudoku puzzle. Worse, the surgeon might be commenting on your humongous intra-abdominal fat. You lie there, full of fear, wishing this is just a dream but it isn't. Worse, you couldn't move.

Everyday awareness during anaesthesia is experienced by about 100 people in the theatre in US alone. Having had some experience with anaesthesia (I spent one year doing a research in the Anaesthesia department), I am glad I have never come across any horror stories in the theatre. While horror stories like this may deter some people from ever having a surgery in the future, allow me to allay your fear by assuring you that this is very uncommon (only 1 in 1000), and you shouldn't feel any pain even if you wake up.

In the theatre, here are a few things that anesthesiologists / anaesthetists could rely on as an indicator of patient's anesthesia status (from the trivial to the more technical):

1. Patient is not moving. But this is not reliable especially when the patient is given muscle relaxant, as is the case for abdominal surgery like in this woman.

2. Patient's vital signs are not showing sympathetic outflow (BP, heart rate, sweating etc). This could possibly be masked by the other drugs given during surgery. Even if the vital sign changes are noted, it could have simply be perceived as an autonomic reaction towards pain, and interpreted as inadequate analgesia. (Yes your body still react to pain when you are under GA). So the anesthesiologist could have simply given her more IV analgesics instead of checking her consciousness status.

3. The concentration of the volatile agent (gas used to put you under) in the lung, called MAC (minimum alveolar concentration). In most modern hospitals, this is continuously monitored through the anesthetic monitor. Judging from the concentration of volatile agent PLUS opioid analgesics PLUS/MINUS other sedatives (sometimes used), the anesthesiologists have a good indication of whether the patient *should be* asleep.

The problem with this method is that sometimes people have idiosyncratic reaction or tolerance towards particular types of agents, so while statistically a particular combination of MAC and opioid and midazolam could anesthetize 99.99% population, there's no telling who that 0.01% is going to be.

4. Last but not least, an optional (but expensive) monitoring called BIS is used to detect the "brain activity" during anesthesia. This is a series of electrodes attached to the forehead to monitor the electroencephalography (EEG, the "brainwave"). It gives a number from 0 to 100 which roughly translates to the spectrum of consciousness from total brain silence to fully awake. It is not used all the time because of the cost, occasional inaccuracy and the fact that the monitoring above (3) is deemed sufficient.

Regardless of all monitoring and precaution, awareness during anesthesia is a recognised complication during surgery, which, although minimizable, is not 100% preventable. In addition to the idiosyncratic responses mentioned above, in certain surgeries (e.g. in major trauma, elderly patients or pregnant woman) the anesthesiologists in fact go for minimal anesthesia due to their fragile cardiovascular system. So in these population there is a higher risk of awareness, but even for them the risk is about one in a few hundred operations.

Anesthesiologists routinely inform the patients about the risk of awareness when they give consent for the operation. Therefore, though the lady endured a horrifying experience, as long as the anesthesiologists did not make any mistake, she could have simply been unlucky and has no case to make against the doctors.

So go ahead and have your surgeries if you need them. You *should be* in good hands (if you *are* in good hands).

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WP said...

Wow! I read about anaesthesia awareness in an issue of Reader's Digest quite a long time ago, and I thought they had found a way to do something about it! It's scary to see that it wasn't so...

But thanks anyway for the assurance that "you shouldn't feel any pain even if you wake up"...though I'd still prefer not to feel anything at all! :P

kyh said...

omg that sounds so scary. i wonder how long did that lady stay in that state... thx for the assurance anyway lol.

Yew TW said...

well described young!

Anonymous said...

I guess the epidural is still working?


jasmine said...

i first heard about this through the 2007 movie Awake. It's a real cool movie starring jessica alba. Shows this guy's thoughts throughout the surgery.