Background and importance Sedatives are administered to reduce anxiety and stress in mechanically ventilated, critically ill patients. Midazolam and propofol are the sedatives of choice, but their behaviour is difficult to predict in this type of patient. Inhaled sedation with halogenated agents has emerged as an alternative because of their speed of action and elimination.

Aim and objectives To review the available evidence on the use of sedative inhaled gases in the intensive care unit (ICU).

Material and methods A literature search was conducted through the medical databases PubMed and Google Academics using the terms ‘Inhaled sedation’ and ‘Critical care’. Articles comparing inhaled sedation directly with conventional sedation, or describing pioneering uses of inhalation sedation, were selected. Another search with the same keywords was performed using TripDataBase and UpToDate to locate meta-analyses and clinical practice guidelines.

Results 236 articles were located and 25 were selected. No randomised clinical trials were found. Four meta-analyses were located.

Inhaled sedation is described to be effective to achieve deep sedation and to reduce sedation and extubation time; it also favours a decrease in troponin levels. Its use is also relevant in patients who do not achieve adequate sedation with conventional sedation. The gases used were isoflurane and sevoflurane.

There are clinical practice guidelines developed by different societies: American Society of Anesthesiologists, National Institute for Health and Care Excellence, Spanish Society of Intensive Care Medicine and The American Society of Intensive Care Medicine. They consider inhaled sedation as an alternative in patients with bronchospasm and in patients who are difficult to sedate.

Conclusion and relevance It can be concluded that the use of inhaled gases reduces the extubation and awakening time in critically ill patients. A reduction in troponin concentration is observed. However, these are not ‘hard’ variables that demonstrate an important clinical impact.

Their use may be of interest in patients with bronchospasm or in those who do not achieve an adequate sedation with conventional high-dose sedatives.

Conflict of interest No conflict of interest