If you’ve ever been afraid of being put under anesthesia, you’re not alone. From not waking up to regaining consciousness mid-surgery, there are many nightmare scenarios to consider. A new film coming out today plays on another frightening notion: losing the ability to move while remaining conscious.

Don’t move, a new thriller from Netflixfollows a grieving mother named Iris who, after trusting the wrong stranger, is injected with an anonymous paralytic agent that will render her completely immobile within 20 minutes, leaving her at the mercy of this man. The film follows his frantic attempt to outrun his captor as the drugs gradually weaken him. At one point, a kind man living in the woods finds her body and Iris communicates with him through a series of blinks. The result is a bloody, anxiety-inducing chase with a strangely invigorating message.

When it comes to anesthetics, there are many anxieties. Even doctors understand this apprehension about paralysis and loss of control. “I think it’s one of the things patients fear the most. » Akshay Bhattanesthesiologist at New York University Langone Health, says Reverse. “It’s something people worry about all the time.”

Perhaps understanding how these drugs work and the contexts in which they are used could allay some of these fears. And according to science, the movie gets some things wrong about paralyzing agents.

There is four types Anesthesiologists use during surgeries and procedures: general anesthesia, regional anesthesia, sedation and local anesthesia. General anesthesia, which usually involves several different medications, renders you completely unconscious, causing you to lose consciousness and the ability to move (temporarily). These other medications, Bhatt says, typically include paralyzing agents as well as benzodiazepines for anxiety, fentanyl for pain, and propofol for sedation, which also typically cause short-term memory loss. Regional anesthesia blocks sensation in a limb or area of ​​the body, causing numbing pain. Sedation keeps you conscious but in a vague, relaxed state. Local anesthesia, administered by cream or needle, numbs pain in a small area of ​​the body, such as the gums.

Paralytic agents are a component of general anesthesia. Medically, these medications are known as neuromuscular blocking agents. They act on the nervous system, disrupting communication between your brain and your muscles. Your brain usually sends a signal through your nervous system telling your muscles to move. With this message, the neurotransmitter acetylcholine binds to receptors on muscle fibers, like a lock in a key, to initiate movement. But these paralytics hinder this relay.

Bhatt explains that there are two types of blocking agents: non-depolarizing and depolarizing. Non-depolarizing agents bind to the receptors, preventing acetylcholine from binding to them to transmit the message from the brain telling the muscles to contract. With all of these receptors blocked, your muscles are unable to receive the movement message from your brain. Depolarizing agents, however, mimic acetylcholine and, as Bhatt says, overwhelm muscle receptors, leading to significant contraction and relaxation.

These drugs work quickly, Bhatt says, debunking the first major plot point of the film. The protagonist has about 20 minutes from the time of injection to complete muscle shutdown, but Bhatt says these blocking agents can take effect within 90 seconds.

It is unknown how long Iris remains totally paralyzed, but soon after, she begins to regain the ability to move fragmentarily. However, Bhatt says that depolarizing agents have both rapid effect and compensation; without continuous administration, their effects may fade between 7 and 12 minutes later. It is therefore not necessarily realistic for a single injection to paralyze her for potentially hours.

On a darker note, paralytics actually work on all of your muscles, including the ones that help you breathe. In the operating room, Bhatt says, “we have to breathe for the patient,” which can involve controlled ventilation or endotracheal intubation. In other words, a completely paralyzed person cannot breathe on their own, and without assistance they will die either from ischemia, which is when the organs do not receive enough blood, or from an event hypoxic, which is when the muscles and organs do not receive enough blood. receive enough oxygen. Either way, it’s horrible. Iris would not survive her paralysis, even with the help of the kind hermit who finds her immobile. Nor would she be able to communicate with him by blinking, nor would she be able to throw her paralyzed body into a hiding place, even with an adrenaline rush.

But rest assured: you will almost never find yourself in a position in a hospital where a doctor will use a paralytic alone. Bhatt says it’s rare for doctors to administer a paralytic alone without other medication for anxiety, pain and sedation.

But while Don’t move is not an entirely accurate representation of how paralyzing agents work, its central fear comes from a real possibility. A sadist could certainly paralyze someone if he wanted to, Bhatt says.

“That would be a very nasty thing to do,” he said before adding, “and it would pose a huge legal problem.”