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 sedation:

  • 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 & cardiopulmonary stability.

A core clinical learning outcome of the 2015 RCEM curriculum for CT1 and CT2 is the provision of safe and effective sedation to ASA 1 and 2 1 adult patients (table 1), aged less than 80 years of age using a maximum of two short acting agents. The knowledge and skill competencies expected are listed in table 2. Safe sedation of children is covered in Paediatric EM Practical procedures for ST4-6. The 2012 report and recommendations by the Royal College of Anaesthetists and RCEM Safe Sedation of Adults in the Emergency Department covers deeper levels of sedation 2.

Table 1: American Society of Anesthesiologists Physical Status Classification
Class Description Examples
I Normal, healthy patient
II Mild systemic disease Asthma, controlled diabetes
III Moderate systemic disease Stable angina, diabetes with hyperglycaemia, moderate chronic obstructive pulmonary disease
IV Severe systemic disease Unstable angina, diabetic ketoacidosis
V Moribund
Table 2: RCEM curriculum competencies required for procedural sedation
Can explain:

• What is meant by conscious sedation and why understanding the definition is crucial to patient safety

• The differences between conscious sedation and deep sedation and general anaesthesia

• The fundamental difference in techniques/drugs used/patient safety

• That the significant risks to patient safety associated with sedation technique requires meticulous attention to detail, the continuous presence of a suitably trained individual with responsibility for patient safety, safe monitoring and contemporaneous record keeping

• The use of single drug, multiple drug and inhalation techniques

• The minimal monitoring required during pharmacological sedation


Can describe:

• The pharmacology of drugs commonly used to produce sedation

• The indications for the use of conscious sedation

• The particular risks of multiple drug sedation techniques


Can outline the unpredictable nature of sedation techniques in children
Can demonstrate the ability to:

• Select patients for whom sedation is appropriate part of clinical management

• Explain sedation to patients and to obtain consent

• Administer and monitor inhalational sedation to patients for clinical procedures

• Administer and monitor intravenous sedation to patients for clinical procedures

• Recognise and manage the complications of sedation techniques appropriately including recognition and correct management of loss of verbal responsiveness

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ASA classifications is important, definitely coming in the exam eat one point.

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