The problem is that people think of anesthesia as a single thing when it really has many different components that are managed separately. Unconsciousness is part of it, but so are analgesia (pain relief), paralysis (inability to move), immobility (loss of reflexes), and to a lesser extent, amnesia.
Anesthesia routinely involves the use of paralytics, which are separate from drugs used for analgesia (opioids or local/regional blocks) and inducing unconsciousness (propofol, anesthetic gasses). This can lead to situations where someone is paralyzed, their pain is under control (as observed by blood pressure), but the gas or propofol is insufficient to actually induce unconsciousness. Some of this comes down to individual physiology. Some of it is probably mistakes in anesthesia management.
Amnesia comes into this with the use of benzodiazepines. They can reduce anxiety before surgery. Or even during surgery if the patient needs to be awake. As a bonus, they can prevent memories from forming. Propofol can also cause amnesia, but it is primarily used to suppress consciousness.
Anesthesia routinely involves the use of paralytics, which are separate from drugs used for analgesia (opioids or local/regional blocks) and inducing unconsciousness (propofol, anesthetic gasses). This can lead to situations where someone is paralyzed, their pain is under control (as observed by blood pressure), but the gas or propofol is insufficient to actually induce unconsciousness. Some of this comes down to individual physiology. Some of it is probably mistakes in anesthesia management.
Amnesia comes into this with the use of benzodiazepines. They can reduce anxiety before surgery. Or even during surgery if the patient needs to be awake. As a bonus, they can prevent memories from forming. Propofol can also cause amnesia, but it is primarily used to suppress consciousness.