Just as the history of sedation is a continuum of events and discoveries, it is important to understand that sedation itself is a continuum. The boundaries between the different levels of sedation may not always be evident to the untrained or inexperienced and progression from one level to a higher level may quickly occur as patients do not always respond predictably to any particular sedative agent, i.e., they may respond idiosyncratically. Table 1 summarizes the different levels of sedation continuum and their characteristics.
| Level | Responsivness | Airways | Ventilation | Cardiovascular |
|---|---|---|---|---|
| Minimal | Normal | Not affected | Not affected | No change |
| Moderate | Purposeful response | Open | Adequate | Maintained |
| Deep | Repeated painful stimulus | May need assistance | Ventilation may be impaired | Usually maintained |
| General | No response/not easily aroused | Often needs assistance | Impaired/needs support | May be impaired |
