Nosocomial pneumonia.

Nosocomial pneumonia, or terminal pneumonia as it was formerly called, results from the repetitive microaspiration of contaminated oropharyngeal secretions into the lungs in the presence of impaired host defenses. This pathophysiologic sequence was suggested by the observations of Osler but clarified by the seminal work of Rouby and colleagues. The enormous impact of antimicrobial agents on the organisms responsible for nosocomial pneumonias was first identified by Kneeland and Price who found that organisms of the normal pharyngeal flora virtually disappeared in terminal pneumonias following administration of these drugs, being replaced by gram-negative bacilli. The remarkable susceptibility of seriously ill patients to becoming colonized by exogenous organisms, even in the absence of antimicrobial therapy, was shown by Johanson et al. These factors, antibiotics and the change in bacterial binding receptors in the airways associated with illness, lead to infections caused by exogenous organisms that are frequently resistant to antimicrobial agents. Clinical findings that usually identify patients with respiratory infections are unreliable for the diagnosis of nosocomial pneumonias as shown by Andrews et al. Invasive techniques, especially the protected specimen brush (PSB) technique, avoid contamination of the specimen by proximal secretions and accurately reflect the bacterial burden of the lung, as first shown by Chastre et al. Quantitation of such specimens serves as an excellent proxy for direct cultures of the lung and are the current gold standard for diagnosis.

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.

History of Mendelson's syndrome.

The history of Mendelson's Syndrome is briefly covered and the current problem of the condition in regard to prevention, amelioration and treatment is discussed.