Rapid sequence induction: a narrative review

INTRODUCTION: Pulmonary aspiration of gastric contents remains an important cause of anaesthetic morbidity and mortality, and is important medicolegally. Rapid sequence induction is a multi-element technique designed to mitigate risk in those patients at increased risk of pulmonary aspiration during induction of general anaesthesia. METHODS: We undertook a narrative review to summarise evidence and evidence gaps focusing on controversial aspects of rapid sequence induction. RESULTS: Despite widespread use of rapid sequence induction, many elements of the technique lack robust evidence and consensus. Nasogastric tubes can be used to reduce gastric content, but do not empty the stomach reliably. Correctly applied cricoid force obstructs the hypopharynx and has a limited impact on airway management, but incorrect application can cause clinically significant difficulties. Correct location of cricoid force may require ultrasound localisation of the cricoid cartilage. Applying the correct force, which varies with age and sex, is improved by education, practice and feedback. The use of videolaryngoscopy during rapid sequence induction is supported by evidence. The role of gastric ultrasound in determining anaesthetic technique is uncertain. Cardiovascular complications of rapid sequence induction are common, particularly in the patients who are critically ill, and modifications to the technique may reduce their frequency and severity. Effective use of airway rescue techniques may require removal of cricoid force. DISCUSSION: There is insufficient evidence for many of the elements of rapid sequence induction to determine whether they reduce patient harm or to state confidently that they do not. Controversies and evidence gaps should be acknowledged. Despite this, optimal use of rapid sequence induction requires a thorough knowledge of the subject, including areas of uncertainty to guide individualised risk assessment; clinical decision-making; and practical conduct of the technique.