British journal of anaesthesia

Abstract

The majority of mechanically ventilated patients in the intensive care unit (ICU) require sedation to reduce anxiety, encourage sleep and to increase tolerance to tracheal tubes and the ventilator. Sedative and analgesic drugs are amongst the most commonly prescribed medications in the ICU. 1 The choice of agent and the way in which they are used varies widely between and within ICUs. In a survey of 164 ICUs in the US, 2 18 different sedative agents were used, the commonest of which were the opiates and benzodiazepines. A more recent study 3 revealed substantial differences in the clinical use of drugs for sedation and analgesia in the western European countries surveyed. These differences in clinical practice can have an important impact on patient outcome and cost of care: excessively deep sedation will prolong ventilator depend-ence and length of stay in the ICU, which can be avoided by careful monitoring and interruption of sedative infusions. 4 5 But failure to provide appropriate sedation and analgesia may add to the well-recognised psychological burden of critical illness for patients, 6 7 and indirectly for relatives. The appropriate use of sedative drugs is an important process measure of quality of care. 8 But to tread the ®ne line between adequate comfort and avoidance of excessive sedation demands both the use of clinically relevant sedation scales, 9 10 and the availability of morèresponsive' sedative agents. The volatile anaesthetic agents offer considerable potential in this respect. In this issue of the journal, Meiser and colleagues 11 report the use of the inhalation anaesthetic des¯urane and compare it with propofol for postoperative sedation in the ICU. Inhalation anaesthetic agents have been used for sedation for many years. Sir Humphry Davy ®rst suggested that nitrous oxide inhalation could be used to provide analgesia and sedation during surgical operations more than 200 years ago. In the 1960s, using nitrous oxide in a technique callerelative analgesia', Langa 12