The anesthesiologist or anesthetist will need to carefully monitor your breathing during and after your surgery. Before you undergo general anesthesia, your anesthesiologist will talk with you and may ask questions about:.
Your anesthesiologist usually delivers the anesthesia medications through an intravenous line in your arm. Sometimes you may be given a gas that you breathe from a mask.
Children may prefer to go to sleep with a mask. Once you're asleep, the anesthesiologist may insert a tube into your mouth and down your windpipe. The tube ensures that you get enough oxygen and protects your lungs from blood or other fluids, such as stomach fluids. You'll be given muscle relaxants before doctors insert the tube to relax the muscles in your windpipe.
Your doctor may use other options, such as a laryngeal airway mask, to help manage your breathing during surgery. Someone from the anesthesia care team monitors you continuously while you sleep.
He or she will adjust your medications, breathing, temperature, fluids and blood pressure as needed. Any issues that occur during the surgery are corrected with additional medications, fluids and, sometimes, blood transfusions. When the surgery is complete, the anesthesiologist reverses the medications to wake you up.
You'll slowly wake either in the operating room or the recovery room. You'll probably feel groggy and a little confused when you first wake. You may experience common side effects such as:. You may also experience other side effects after you awaken from anesthesia, such as pain.
Your anesthesia care team will ask you about your pain and other side effects. Side effects depend on your individual condition and the type of surgery. Your doctor may give you medications after your procedure to reduce pain and nausea. Explore Mayo Clinic studies of tests and procedures to help prevent, detect, treat or manage conditions. Mayo Clinic does not endorse companies or products.
Advertising revenue supports our not-for-profit mission. This content does not have an English version. This content does not have an Arabic version. Overview General anesthesia is a combination of medications that put you in a sleep-like state before a surgery or other medical procedure. Share on: Facebook Twitter. Show references Falk SA, et al. Overview of anesthesia. Accessed Nov. Brunton LL, et al. But, there is a fine line between the amount of these drugs needed for surgery and the amount that can be fatal; these drugs were often administered with nothing more than a soaked sponge to the nose, which made it hard to control the dose.
Today, the most common modern general anesthetics are mixtures of inhalable gases, which include nitrous oxide laughing gas and various derivatives of ether, such as Isoflurane, Sevoflurane, and desflurane. Skilled anesthesiologists administer the drugs via machines that measure the specific amount necessary to keep the patient out for the surgery, but not forever.
Additionally, because the drugs interfere with breathing, patients are often intubated — meaning a plastic or rubber tube is inserted in the trachea to keep the airway open — and kept on a mechanical ventilator. Despite their necessity in modern medicine, scientists aren't sure exactly how anesthetics work. But, the precise mechanisms remain unknown. But despite their importance, scientists still don't understand exactly how general anesthetics work.
Now, in a study published this week in the Journal of Neuroscience , researchers from the Okinawa Institute of Science and Technology Graduate University OIST and Nagoya University have revealed how a commonly used general anesthetic called isoflurane weakens the transmission of electrical signals between neurons, at junctions called synapses. At synapses, signals are sent by presynaptic neurons and received by postsynaptic neurons. At most synapses, communication occurs via chemical messengers -- or neurotransmitters.
When an electrical nerve impulse, or action potential, arrives at the end of the presynaptic neuron, this causes synaptic vesicles -- tiny membrane 'packets' that contain neurotransmitters -- to fuse with the terminal membrane, releasing the neurotransmitters into the gap between neurons. When enough neurotransmitters are sensed by the postsynaptic neuron, this triggers a new action potential in the post-synaptic neuron. The scientists induced electrical signals at different frequencies and then detected the action potentials generated in the postsynaptic neuron.
They found that as they increased the frequency of electrical signals, isoflurane had a stronger effect on blocking transmission. To corroborate his unit's findings, Takahashi reached out to Dr. Takayuki Yamashita, a researcher from Nagoya University who conducted experiments on synapses, called cortico-cortical synapses, in the brains of living mice. Yamashita found that the anesthetic affected cortico-cortical synapses in a similar way to the calyx of Held.
When the mice were anesthetized using isoflurane, high frequency transmission was strongly reduced whilst there was less effect on low frequency transmission. With further research, the researchers found that isoflurane reduced the amount of neurotransmitter released, by both lowering the probability of the vesicles being released and by reducing the maximum number of vesicles able to be released at a time.
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