Differentiating standard geometry and hyperangulated video laryngoscope blades by handle-blade angle, blade curvature, and camera field of view
- 1Hennepin County Medical Center
Abstract
BackgroundVideo laryngoscopes are classically grouped into standard geometry (Macintosh-style) and hyperangulated classes. However, this distinction rests on the original Glidescopes historically cited 60{degrees} angle rather than any recognized definition of a blades "angle." Different methods of measuring angulation of a blade yield angles that differ by 30{degrees} or more, and blades are classified by convention rather than by measurement. We developed standardized geometric measurements and determined which best discriminate between the two blade types.
MethodsIn a bench study of 23 commercially produced adult laryngoscope blades, we measured (i) blade and camera angles relative to the handle, (ii) intrinsic blade curvature from heel to tip, and (iii) camera field of view. The primary analysis compared measurements from 11 standard geometry video laryngoscopes and 8 non-channeled, hyperangulated video laryngoscopes. We report medians and Hodges-Lehmann median differences with 95% confidence intervals.
ResultsThe handle-referenced blade tip angle did not distinguish the classes (median 40{degrees} standard geometry vs 48{degrees} hyperangulated; median difference 8{degrees}, 95% CI -5{degrees} to 16{degrees}), and the vertical video field of view did not differ (34{degrees} vs 37{degrees}; difference 3{degrees}, 95% CI -1{degrees} to 9{degrees}). The intrinsic blade curvature, measured without relation to the handle, differed between classes. Hyperangulated blades had a larger heel-to-tip deflection angle (80{degrees} vs 49{degrees}; difference 31{degrees}, 95% CI 21{degrees} to 40{degrees}) and a smaller average radius of curvature (70 vs 113 mm; difference -42 mm, 95% CI -57 to -28 mm) despite similar arc length (119 vs 120 mm).
ConclusionsIntrinsic blade curvature, rather than the field of view or often-cited angle between the handle and blade tip, best distinguished standard geometry from hyperangulated video laryngoscopes. Reporting shape-based geometry measurements would support consistent classification and comparison.
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BibTeX
@misc{driver2026differentiating,
title = {{Differentiating standard geometry and hyperangulated video laryngoscope blades by handle-blade angle, blade curvature, and camera field of view}},
author = {B. E. Driver and S. A. Trent and S. C. DeMasi and A. E. Robinson and M. E. Prekker},
howpublished = {medRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.22.26366035},
url = {https://www.medrxiv.org/content/10.64898/2026.10.22.26366035v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Differentiating standard geometry and hyperangulated video laryngoscope blades by handle-blade angle, blade curvature, and camera field of view
AU - B. E. Driver
AU - S. A. Trent
AU - S. C. DeMasi
AU - A. E. Robinson
AU - M. E. Prekker
PY - 2026
DA - 2026/10/22
PB - medRxiv
DO - 10.64898/2026.10.22.26366035
UR - https://www.medrxiv.org/content/10.64898/2026.10.22.26366035v1
AB - BackgroundVideo laryngoscopes are classically grouped into standard geometry (Macintosh-style) and hyperangulated classes. However, this distinction rests on the original Glidescopes historically cited 60{degrees} angle rather than any recognized definition of a blades "angle." Different methods of measuring angulation of a blade yield angles that differ by 30{degrees} or more, and blades are classified by convention rather than by measurement. We developed standardized geometric measurements and determined which best discriminate between the two blade types. MethodsIn a bench study of 23 commercially produced adult laryngoscope blades, we measured (i) blade and camera angles relative to the handle, (ii) intrinsic blade curvature from heel to tip, and (iii) camera field of view. The primary analysis compared measurements from 11 standard geometry video laryngoscopes and 8 non-channeled, hyperangulated video laryngoscopes. We report medians and Hodges-Lehmann median differences with 95% confidence intervals. ResultsThe handle-referenced blade tip angle did not distinguish the classes (median 40{degrees} standard geometry vs 48{degrees} hyperangulated; median difference 8{degrees}, 95% CI -5{degrees} to 16{degrees}), and the vertical video field of view did not differ (34{degrees} vs 37{degrees}; difference 3{degrees}, 95% CI -1{degrees} to 9{degrees}). The intrinsic blade curvature, measured without relation to the handle, differed between classes. Hyperangulated blades had a larger heel-to-tip deflection angle (80{degrees} vs 49{degrees}; difference 31{degrees}, 95% CI 21{degrees} to 40{degrees}) and a smaller average radius of curvature (70 vs 113 mm; difference -42 mm, 95% CI -57 to -28 mm) despite similar arc length (119 vs 120 mm). ConclusionsIntrinsic blade curvature, rather than the field of view or often-cited angle between the handle and blade tip, best distinguished standard geometry from hyperangulated video laryngoscopes. Reporting shape-based geometry measurements would support consistent classification and comparison.
ER -