Introduction

Sedation is a routine aspect of emergency care. The aim is clear: make the procedural experience as comfortable as possible for your patient, whilst ensuring that your practice is safe.

Sedation is a continuum which extends from a normal conscious level to being fully unresponsive. Sedation and recovery move patients along this scale, but it is difficult to accurately assess the precise degree of sedation at any one time, and even harder to maintain a patient at a pre-defined target level.

The American Society of Anesthesiologists (ASA) uses the following useful definitions for sedation¹:

• Minimal Sedation (Anxiolysis) is a drug-induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory and cardiovascular functions are unaffected.
• Moderate Sedation/Analgesia (‘Conscious Sedation’) is a drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained. In the Emergency Department this is most often achieved using a combination of opioids and benzodiazepines.
• Deep Sedation/Analgesia is a drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation. The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.
• General Anaesthesia is a drug-induced loss of consciousness during which patients are not rousable, even by painful stimulation. The ability to independently maintain ventilatory function is often impaired. Patients require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function. Cardiovascular function may also be impaired.

Not included in the classification is ‘dissociative sedation’, uniquely produced by ketamine it is a   trance like cataleptic state characterized by profound analgesia and amnesia, with retention of protective airway reflexes, spontaneous respirations and cardiopulmonary stability.

A core clinical learning outcome of the 2021 RCEM curriculum for CT1 and CT2 is the planning and delivery of “safe sedation using appropriate agents for ASA 1E and 2E (table 1) patients requiring procedures.² Safe sedation of children is a key outcome for ST4 – 6 training.²