SummaryThe Bonfils Intubation Fibrescope is a rigid optical instrument for performing orotracheal intubation. We describe its introduction into our clinical practice in 60 patients with normal airways who required orotracheal intubation for elective surgery. Two anaesthetists each performed 30 attempts to intubate, in turn, in patients who received a standard general anaesthetic with neuromuscular blockade. Intubation was successful in 59 out of 60 cases. The median (IQR [range]) time to intubation was 33 s (24-50 [13-180] s). Median (IQR [range]) verbal rating score for difficulty was 2 (1-3 [0-10]). There was a significant correlation between the intubation times and the verbal rating score (p < 0.01). There was evidence of airway trauma in the single patient in whom intubation failed. The Bonfils Intubation Fibrescope is an effective instrument for orotracheal intubation in normal subjects.

Nasal patency was measured by five techniques in 24 subjects and the results compared. In addition three pulmonary parameters were measured as well as height and weight. Nasal resistance to airflow measured by active anterior rhinomanometry was found to be highly correlated with peak nasal inspiratory flow rate. Other correlations were also noted. Peak nasal inspiratory flow was itself highly correlated with pulmonary peak expiratory flow rate as well as with several other parameters. The possible reasons for these correlations are discussed in terms of fluid mechanics.

SummaryThe t>entilution-exchange bougie is a new airway device which can be mounted on afibreoptic laryngoscope for passage through the larynx into the trachea via a laryngeal mask airway.

Study of patients who exhibit only limited morphological abnormality yet present difficulty with direct laryngoscopy is facilitated by a standard intubating position. The "Angle Finder" instrument allows implementation of a simple reproducible geometric standard which is applied easily in formal research work and in clinical practice and teaching. The proposed standard relates to the curved (Macintosh) laryngoscope blade and a supine patient. The lower neck flexion is 35 degrees and extension of the plane of the face 15 degrees, each angle measured relative to horizontal. Initially, the standard was derived from a review of the literature, then validated in a study of the intubating practices of 10 senior anaesthetists. A more detailed study of 10 normal volunteers confirmed reproducibility and, for nine patients with a history of difficult direct laryngoscopy, the standard was shown to be appropriate.

Laryngoscope blade design has tended to be relatively arb#rary and so far scientific analysis has not allowed useful comparisons between blade shapes. A new theoretical method of analysing laryngoscope blades is introduced and uses the depth of in