Using the bubble inclinometer to measure laryngeal tilt and predict difficulty of laryngoscopy.
OBJECTIVE
To evaluate a simple device, the bubble inclinometer, to measure degrees of laryngeal tilt (LT) for predicting difficulty of direct laryngoscopy using a Macintosh #3 laryngoscope.


METHODS
Randomized, double-blind study.


METHODS
Inpatient surgery center at a university medical center.


METHODS
50 renal lithotripter patients.


METHODS
Patients were measured with the bubble inclinometer and the laryngeal indices caliper. A sleep dose of thiopental sodium (4 mg/kg) and a muscle-relaxing dose of succinylcholine (1 mg/kg) were then given to each patient.


RESULTS
LT was measured by both methods (directly and indirectly). Difficulty of laryngoscopy was graded as follows: Grade 1 = all of vocal cords seen; Grade 2 = part of vocal cords seen; Grade 3 = no part of vocal cords seen.


CONCLUSIONS
The bubble inclinometer accurately and reproducibly measures relative LT, and the anterior tilt of the larynx directly correlates with the ability to see the laryngeal opening during direct laryngoscopy with a Macintosh #3 laryngoscope.
Roberts
J T
JT
Department of Anesthesia, Massachusetts General Hospital, Boston 02114.
Ali
H H
HH
Shorten
G D
GD
D000328:Adult; D004311:Double-Blind Method; D005069:Evaluation Studies as Topic; D005260:Female; D005544:Forecasting; D006801:Humans; D007669:Kidney Calculi / Q000628:therapy; D020704:Laryngoscopes; D007828:Laryngoscopy / Q000379:methods; D007830:Larynx / Q000033:anatomy & histology*; D008096:Lithotripsy; D008297:Male