A Comparison of Three Videolaryngoscopes: The Macintosh Laryngoscope Blade Reduces, but Does Not Replace, Routine Stylet Use for Intubation in Morbidly Obese Patients

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Abstract
Many manufacturers are producing videolaryngoscopes (VLSs) with differing specifications, user interfaces, and geometry. It is clinically relevant to know the relative performance of the blades. Visualization of the glottis and intubation are often problematic in (extremely) obese patients, and the new video technology may offer better functionality and performance. Although many tracheal intubations with direct laryngoscopy are performed with an unstyletted endotracheal tube, it is recommended to use a stylet for intubation using videolaryngoscopy. In this study, we compared 3 VLSs in morbidly obese patients undergoing intubation for elective surgery and tested whether it is feasible to intubate the tracheas of morbidly obese patients without using a stylet. One hundred fifty consecutive adult morbidly obese patients (body mass index >35 kg/m(2)) were randomly selected to receive one of 3 VLSs: GlideScope, Storz V-Mac, and McGrath. Direct laryngoscopy scored the best possible view of the glottis; subsequently, the respective VLS was used, and the patient's trachea was intubated. Common preprocedural (e.g., Mallampati grade) and intraprocedural (Cormack-Lehane grade) metrics of intubation difficulty were measured, as well as the dependent variables of intubation time, number of attempts, and subjective difficulty. All 3 VLSs tested offered an equal or better view of the glottis compared with traditional direct laryngoscopy. The number of attempts necessary to intubate the trachea differed significantly among VLSs (average 2.6 +/- 1.0 attempts for the GlideScope, 1.4 +/- 0.7 for the Storz, and 2.9 +/- 0.9 for the McGrath VLS). The average intubation times were 33 +/- 18 s for the GlideScope, 17 +/- 9 s for the Storz, and 41 +/- 25 s for the McGrath VLS. In this study, the VLS with the Macintosh blade (Storz VLS) had a better overall satisfaction score, intubation time, number of intubation attempts, and necessity of extra adjuncts, compared with the 2 other tested devices.
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