A method for objective evaluation of the difficulty of endotracheal intubation is described. Our data indicate that the angle formed by the light-beam axis of the laryngoscope blade and the laryngotracheal axis, which we call “angle ϕ”, is analogous to the degree of difficulty of endotracheal intubation. Using this method, we compared the effectiveness of a standard Macintosh and a modified bevelled Macintosh blade in 27 tracheostomized Intensive Care Unit patients under general anaesthesia. Statistical analysis of our results indicate that the bevelled blade significantly facilitates endotracheal intubation.
LattoP.I., RosenM.Difficulties in tracheal intubation.Baillière Tindall, London, 1984.
3.
CormackR.S., LehaneJ.Difficult tracheal intubation in obstetrics.Anaesthesia1984; 39: 1105–1111.
4.
StoneD.J., GalT.J.Airway management.MillerR.D., ed. Anaesthesia.New York, Churchill Livingstone, 1994; 1403–1437.
5.
AlexopoulosC., LarssonS.G., LindholmC.E.Anatomical shape of the airway.Acta Anaesthesiol Scand1983; 27: 185–192.
6.
HortonW.A., FahyL., CharterP.Defining a standard intubation position using “angle finder”.Br J Anaesth1989; 62: 6–12.
7.
BatsheletE.Circular statistics in biology.London, Academic Press Inc, 1981; 112–114.
8.
GrantG.L.A new laryngoscope.Anaesth Intens Care1977; 5: 263–264.
9.
KesselJ.A.A laryngoscope for obstetrical use.Anaesth Intens Care1977; 5: 265–266.
10.
JellicoeJ.A., HarrisN.R.A modification of a standard laryngoscope for difficult tracheal intubation in obstetric cases.Anaesthesia1984; 39: 800–802.
11.
RaczG.B.Improved vision modification of the MacIntosh laryngoscope.Anaesthesia1984; 39: 12249–12250.
12.
CallanderC.C., ThomasJ.Modification of MacIntosh laryngoscope for difficult intubation.Anaesthesia1987; 42: 671–672.
13.
NunnG.A new laryngoscope. A modified laryngoscope to facilitate intubation in case of restricted access.Anaesthesia1987; 42: 877–878.
14.
BellhouseC.P.An angulated laryngoscope for routine and difficult tracheal intubations.Anesthesiology1988; 69: 126–129.
15.
SylvaneE., StoolA.Intubation techniques for the difficult airway.Paed Infec Dis J1988; 7: 154–156.
16.
SchereR., HabelG.A modified MacIntosh blade with adjustable tip for difficult intubation.Anaesthesie Intensiv Therapie Notfallmedizine1990; 25: 432–435.
