Summary Difficult intubation has been classified into four grades, according to the view obtainable at laryngoscopy. Frequency analysis suggests that, in obstetrics, the main cause of trouble is grade 3, in which the epiglottis can be seen, but not the cords. This group is fairly rare so that a proportion of anaesthetists will not meet the problem in their first few years and may thus be unprepared for it in obstetrics. However the problem can be simulated in routine anaesthesia, so that a drill for managing it can be practised. Laryngoscopy is carried out as usual, then the blade is lowered so that the epiglottis descends and hides the cords. Intubation has to be done blind, using the Macintosh method. This can be helpful as part of the training before starting in the maternity department, supplementing the Aberdeen drill.

No abstract

Summary Difficult intubation has been classiJied into four grades

The effect of increasing end-tidal enflurane concentration on the auditory evoked response was studied in six patients. After a standard induction, anesthesia was maintained with 70% nitrous oxide in oxygen and the end-tidal enflurane concentration was increased gradually from 0 to 1% over a period of 30 min. The averaged auditory evoked response was derived from the electroencephalogram and measurements were made of the latencies and amplitudes of waves I, III, V, Pa and Nb within the auditory evoked response. The latencies of all waves and the interpeak latencies I to V and III to V showed significant linear increases and the amplitudes of Pa and Nb showed significant linear decreases with increasing end-tidal enflurane concentration. These results could not be explained by changes in deep body temperature or end-tidal carbon dioxide concentration. The study demonstrated a dose-related direct effect of enflurane on the brainstem and early cortical components of the auditory evoked response.

Testosterone was measured in the peripheral blood plasma of normal men by radioimmunoassay. The results were analysed to test for the possible existence of a circadian rhythm, for fluctuations superimposed on any such rhythm, and for day-to-day variations.