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Summary A bench-top study was performed to assess the effects of different laryngoscope handles on the light intensity delivered from disposable metal or plastic laryngoscope blades. The light intensity from both the handle light sources themselves and the combined handle and laryngoscope blade sets was measured using a custom-designed testing system and light meter. Five samples of each disposable blade type were tested and compared with a standard re-usable stainless steel blade using three different handle/light sources (Vital Signs LED, Heine 2.5 V Xenon and 3.5 V Xenon). The light intensity delivered by the disposable blades ranged from 790 to 3846 lux for the different handle types. Overall, the 3.5 V Heine handle delivered the highest light output (p

Summary We aimed to determine if using the EndoFlex® tracheal tube on the first intubation attempt provided improved placement times and intubation success compared with a standard-type tracheal tube in 50 patients undergoing gynaecological surgery in a prospective, randomised, cross-over trial. We found that using the EndoFlex resulted in shorter intubation times (mean (SD) 14.8 (9.7) vs 30.1 (30.5) s), easier intubation (VAS, median (range) 10 (0–70) vs 20 (0–100)), and an increased rate of successful insertion at the first attempt; all p

Summary We measured the illumination generated by all 30 Macintosh size 3 laryngoscopes in our department with a lux-meter and a standardised laryngoscope holding tube. We found a large range in illumination generated (65–3130 lx). We then measured the effect on the illumination for each laryngoscope by covering the blade with a cover (LaryGard). In every case, the illumination was reduced by the LaryGard, the mean (SD) reduction was 67 (19)%. When we compared the illumination generated by a disposable laryngoscope blade with the same power source, we found that the illumination was reduced less than with the standard Macintosh covered by a LaryGard.

Baraka A, 1999, ANESTHESIOLOGY, V90, P332, DOI 10.1097-00000542-199901000-00063; Taha SK, 2006, ANAESTHESIA, V61, P427, DOI 10.1111-j.1365-2044.2006.04610.x; TELLER LE, 1988, ANESTHESIOLOGY, V69, P980, DOI 10.1097-00000542-198812000-00035

Summary A rigid cervical collar was applied to 102 patients under general anaesthesia. Laryngoscopy was performed using a McCoy laryngoscope blade (size 3) initially in the standard Macintosh configuration followed by activation of the distal hinged tip. The two views obtained at laryngoscopy were graded according to standard guidelines. In 46/102 (45.1%) patients the laryngoscopic view was improved by one or more grades. In 10/102 (9.8%) the view was improved by two grades. Difficult laryngoscopy (grade 3 or 4) was encountered in 26/102 patients using the McCoy laryngoscope in the unactivated position (Macintosh configuration). Of these 26 patients, 24 (92.3%) had glottic structures identified (grade 1 or 2) when the distal tip of the laryngoscope blade was activated (p < 0.001). The McCoy laryngoscope significantly improves the view at laryngoscopy in the patient whose neck is immobilised in a rigid cervical collar.

The Cardiff paediatric laryngoscope blade is a single blade that has been designed for use in children from birth to adolescence. This open, randomised, crossover study compared the Cardiff blade with the straight, size 1, Miller laryngoscope blade in 39 infants under 1 years of age and the curved, size 2, Macintosh blade in 39 children aged 1-16 years. The same laryngoscopic view was obtained with the Cardiff and Miller blades in 26 patients; the view was better with the Cardiff blade in seven patients and better with the Miller blade in six (median (IQR [range]) grade of laryngoscopy 1 (1-2 [1-3]) vs. 1 (1-2 [1-3]), respectively; p = 0.405). The Cardiff blade was faster at gaining a view than the Miller blade (mean (SD) time 8.5 (2.9) s vs. 10.2 (3.5) s, respectively; 95% CI for difference -2.8 to -0.4; p = 0.009). The Cardiff and Macintosh blades produced the same view in 32 patients; the view was better with the Cardiff blade in seven patients (median (IQR [range]) grade of laryngoscopy 1 (1-1 [1-3]) vs. 1 (1-2 [1-3]), respectively; p = 0.008). There was no difference in time to gain these views: mean (SD) 8.7 (3.0) s vs. 9.3 (2.7) s, respectively (95% CI for difference -1.58 to 0.40; p = 0.237). The Cardiff paediatric laryngoscope blade compares favourably with these two established laryngoscope blades in children.

The Vital View laryngoscope (Vital Signs, NJ, USA) consists of a plastic disposable blade containing a fibrelight and a non-disposable handle; there is therefore no need to sterilise the blade and no concern about disintegration of the fibrelight. In a random cross-over design, we compared the Vital View laryngoscope with a conventional metal fibrelight laryngoscope (Welch Allyn, NY, USA) in 100 patients. The Vital View laryngoscope produced a brighter field than the metal laryngoscope (p < 0.001), whereas there was no significant difference in the view of the glottis or the success rate of tracheal intubation. In no patient did any problem occur, such as damage to the laryngoscope blade or loss of light during laryngoscopy. In another 10 patients, prevention of light emission from the side of the laryngoscope blade reduced the brightness (p < 0. 01). This indicated that the brightness of the Vital View laryngoscope is produced by light emission not only from the tip of the blade but also from the side of the blade. Therefore, the disposable Vital View laryngoscope can be used as effectively as a conventional non-disposable laryngoscope.

The forces transmitted by the laryngoscope blade onto the base of the tongue are assumed to be a major cardiovascular stimulus. This study investigates the various forces applied onto a Macintosh laryngoscope during laryngoscopy. The forces acting along the axis of the handle are described, as well as the forces exerted by the anaesthetist to prevent the laryngoscope from turning. Based on a relatively simple technique, a modified laryngoscope has been designed to measure these forces. Four different laryngoscopic parameters are determined: (1) the duration of laryngoscopy, (2) the maximally applied force, (3) the mean force and (4) the integral of the force over the time (area under the curve). The force measurements of 49 anatomically normal patients undergoing uncomplicated intubation are included in the study. The duration of laryngoscopy was 16.3s (SD 11.8), the applied peak force was 35N (SD 12) and mean force necessary was 20N (SD 6) while the force-time integral was 324N (SD 194).

Tracheal intubation may be hindered by difficulty in insertion of the laryngoscope blade into the patient's mouth because the handle impinges on the patient's chest or on the hand of an assistant applying cricoid pressure. An adaptor is described which modifies the standard Penlon laryngoscope to enable lateral swivelling of the handle, thus avoiding the obstruction.

A technique is described of laryngoscopy under general anaesthesia and curarisation using a modification of the Sanders oxygen injection. A plastic catheter is introduced into the trachea through a brass tube fitted on to the laryngoscope blade and oxygen is injected intermittently through the catheter to provide ventilation. Operating conditions are excellent and serial blood-gas measurements on six patients showed that a safe level of Pao2, Paco2 and pH can be maintained.