Self-Motivation
David Goggins
Former Navy Seal
Career Development
Bryan Cranston
Actor
Critical Thinking
Liv Boeree
International Poker Champion
Emotional Intelligence
Amaryllis Fox
Former CIA Clandestine Operative
Management
Chris Hadfield
Retired Canadian Astronaut & Author
Learn
from the world's big
thinkers
Start Learning

How can doctors tell if you wake up during surgery?

Researchers are only just beginning to really understand anaesthesia awareness.

Waking up during surgery – it's terrifying to think about. But it does happen.


There is evidence that around 5 percent of people may experience so-called anaesthesia awareness at some point on the operating table, though not everyone remembers it.

Living through such an event can be traumatic and painful (read our related story, 'This is what it's like waking up during surgery'). So, what can be done to prevent it?

Anaesthetists have a few tools that can open a channel of communication while a patient is paralysed by neuromuscular blocking drugs.

1. The isolated forearm technique

The isolated forearm technique uses a cuff to stem the flow of blood to the hand, preventing the neuromuscular blocking drugs from paralysing the muscles there. This means that if you're still alert when you should be under anaesthetic, you could move your hand to signal to the doctors and nurses.

It is not often possible to stem the blood flow for very long, however, so this technique can only detect awareness straight after the start of the anaesthesia.

2. Looking at intended movement in the muscles

There may be ways to expand the communication possible with the isolated forearm technique. Federico Linassi at the University Hospital of Padova in Italy is investigating whether it may be possible to measure nerve impulses as a patient is trying to move.

Although the paralytic agents prevent these impulses from stimulating the muscles, the intention still produces measurable electrical activity in the nerves, which, he believes, might offer another way for an awake patient to signal their distress. And, rather than looking at the limbs, Linassi suggests you could detect the intention to move facial muscles such as the mouth.

using electrodes to monitor brain activity

BSIP/Universal Images Group via Getty Images

3. Looking at consciousness in the brain

Some anaesthetists try to measure brain activity during general anaesthesia. The most common method involves attaching electrodes to the skin of the forehead, to measure the firing of neurons in the frontal lobes.

Anaesthetic drugs are supposed to dampen down that activity, with a characteristic pattern of slow waves on the electrode monitor showing that the person really is unconscious. Unfortunately, some recent studies have revealed troubling findings that these brain monitors are unreliable at detecting awareness.

Perhaps they are simply looking in the wrong place? Recent theories of consciousness suggest that our awareness depends on many other brain regions, including the posterior parts.

In the future, researchers may be able to identify a more reliable signature of consciousness, so that an anaesthetist could monitor a patient's level of awareness throughout an operation and adjust the doses according to what they see.

This article first appeared on Mosaic and is republished here under a Creative Commons licence.

LIVE ON MONDAY | "Lights, camera, activism!" with Judith Light

Join multiple Tony and Emmy Award-winning actress Judith Light live on Big Think at 2 pm ET on Monday.

Big Think LIVE

Add event to calendar

AppleGoogleOffice 365OutlookOutlook.comYahoo

Keep reading Show less

Neom, Saudi Arabia's $500 billion megacity, reaches its next phase

Construction of the $500 billion dollar tech city-state of the future is moving ahead.

Credit: Neom
Technology & Innovation
  • The futuristic megacity Neom is being built in Saudi Arabia.
  • The city will be fully automated, leading in health, education and quality of life.
  • It will feature an artificial moon, cloud seeding, robotic gladiators and flying taxis.
Keep reading Show less

Your emotions are the new hot commodity — and there’s an app for that

Many of the most popular apps are about self-improvement.

Drew Angerer/Getty Images
Personal Growth

Emotions are the newest hot commodity, and we can't get enough.

Keep reading Show less

Study details the negative environmental impact of online shopping

Frequent shopping for single items adds to our carbon footprint.

A truck pulls out of a large Walmart regional distribution center on June 6, 2019 in Washington, Utah.

Photo by George Frey/Getty Images
Politics & Current Affairs
  • A new study shows e-commerce sites like Amazon leave larger greenhouse gas footprints than retail stores.
  • Ordering online from retail stores has an even smaller footprint than going to the store yourself.
  • Greening efforts by major e-commerce sites won't curb wasteful consumer habits. Consolidating online orders can make a difference.
Keep reading Show less
Future of Learning

The key to better quality education? Make students feel valued.

Building a personal connection with students can counteract some negative side effects of remote learning.

Scroll down to load more…
Quantcast