There are different levels of anaesthesia. We use the following in surgery.
Local Anaestesia is any technique to induce the absence of sensation in a small part of the body for the aim of inducing local insensitivity to pain. It allows patients to undergo surgical procedures with reduced pain and distress.
Twilight Anesthesia is a moderate sedation– a drug induced depression of consciousness during which the patient responds purposefully to verbal commands. Breathing tubes are not required for this type.
Ventilatory (lung) function is impaired and cardiovascular functions may be impaired. Therefore , breathing tubes (like a laryngeal mask or a tracheal tube) is mandatory, plus ECG, blood pressure, CO2 monitoring etc…