Comparison of two Macintosh laryngoscope blades in 300 patients

• Published in: British journal of anaesthesia : BJA Vol. 90; no. 4; pp. 457 - 460
• Main Authors: Asai, T., Matsumoto, S., Fujise, K., Johmura, S., Shingu, K.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.2003; Oxford University Press; Oxford Publishing Limited (England)
• Subjects: Adolescent; Adult; Aged; Anesthesia; Anesthesia, General; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Anesthesia: equipment, devices; Anthropometry; Biological and medical sciences; Cross-Over Studies; difficult; Equipment Design; equipment, laryngoscopes; Female; Glottis; Humans; intubation tracheal; intubation tracheal, difficult; Intubation, Intratracheal - instrumentation; Laryngoscopes; Laryngoscopy; Male; Medical sciences; Middle Aged; equipment, laryngoscopes; intubation tracheal, difficult; equipment, laryngoscopes; intubation tracheal, difficult; Human; General anesthesia; Intubation; Laryngoscope; Blade; Trachea; Comparative study; Technical equipment; Laryngoscopy
• ISSN: 0007-0912; 1471-6771
• DOI: 10.1093/bja/aeg086

Background. There are two forms of Macintosh laryngoscope blade. Compared with the standard blade, the English blade is longer, its curve is more continuous across the entire length of the blade, the flange of the blade continues much closer to the blade tip, and the height of the flange is shorter. Method. We studied 300 patients to compare the ease of laryngoscopy with each type of Macintosh laryngoscope blade. In a random crossover design, after induction of anaesthesia and neuromuscular block, the two blades were inserted in turn, and the views of the glottis at laryngoscopy (Cormack and Lehane scores) were compared. There was a difference in the view of the glottis in 80 patients. Among these patients, the view was better for the English blade for 63 patients and the standard blade was better for 17 patients. Laryngoscopy was difficult (grade 3 or 4) for at least one blade in 42 of 300 patients (14%). In these 42 patients, there was a difference in the score between the blades in 28 patients; the view was better for the English blade in 25 patients (60%) and for the standard blade in three patients (7%). The view was significantly better for the English blade than for the standard blade (P<0.001; 95% confidence interval 45–74%). In patients in whom laryngoscopy was unexpectedly difficult, the English blade provided a better glottic view significantly more frequently than the standard blade. Br J Anaesth 2003: 90: 457–60