Evolution of 20th century attitudes to prophylaxis of pulmonary aspiration during anaesthesia.

PURPOSE: To describe the evolution of aspiration risk identification and prophylactic management during general anaesthesia as presented in the United Kingdom (UK) anaesthesia textbooks published 1900-1998.
METHODS: The Cumulated Index Medicus, 1900-1997, was searched under the headings: anaesthesia, aspiration, and pneumonia for relevant articles. A classification of features was created using key words and phrases: fasting guidelines, gastric emptying, intestinal obstruction and peritonitis, gastro-oesophageal function, upper oesophageal sphincter, raised intra abdominal pressure, pregnancy, posture and difficult tracheal intubation. Finally, 46 20th century UK anaesthesia text books were studied for the presence or absence of these features.
RESULTS: Throughout the century, intestinal obstruction was a recognized risk factor. Only in the 1940s did some authors mention many of the now known risk factors. Hazards for the pregnant patient were described and in the 1960s the importance of the cricopharyngeus muscle was identified. Prophylactic measures included food and water restriction recommendations, especially in the latter half of the century and gastric lavage and drainage were mentioned throughout the century, as was posture at induction. In the 1950s tracheal intubation began to be routinely recommended. In the 1960s, cricoid pressure appeared and then a burgeoning interest in pharmacological control of gastric content character. Awake tracheal intubation is not always mentioned in 1990-96 textbooks.
CONCLUSION: The consensus of information in textbooks since 1970 was lacking in the previous part of the century. Current textbooks are fewer and are published less frequently. Their role in contemporary anaesthesia education and update merits review.