[Prognostic value of a screening test for difficult microlaryngoscopy].
BACKGROUND
Several screening methods for the prediction of a difficult endotracheal intubation such as the test by Patil or the Mallampati-Score have been described. The incidence of difficult microlaryngoscopic procedures and the prognostic value of those screening tests for their prediction has not been investigated.


METHODS
We examined 81 patients with mainly benign conditions of the larynx in a prospective study to evaluate the maximal overview of the glottis gained during microlaryngoscopy under supraglottic jetventilation. We used a specially designed ruler to measure the length of the invisible portion of the glottis.


RESULTS
The incidence of a difficult microlaryngoscopy was 4.9%. All employed screening scores did not reach a satisfactory positive predictive value (PPV). The routine indirect laryngoscopy with phonation had the highest PPV (50%) of all tests.


CONCLUSIONS
Therefore an impossible indirect laryngoscopy can be regarded as a warning sign for a difficult microlaryngoscopic procedure. Summation-scores like the Arné Multivariate Risk Index or the use of check lists (Benumof) may improve the predictive value of preoperative screening.
Müller
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Klinik und Poliklinik Für, Hals-Nasen, Universitäts-HNO-Klinik Jena, Lessingstrasse 2, 07740 Jena. a.mueller@med.uni-jena.de
Verges
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Gottschall
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R
D000328:Adult; D000368:Aged; D004867:Equipment Design; D005260:Female; D006611:High-Frequency Jet Ventilation / Q000295:instrumentation; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation*; D007818:Laryngeal Diseases / Q000175:diagnosis / Q000601:surgery*; D020704:Laryngoscopes; D007830:Larynx / Q000601:surgery; D008297:Male; D008403:Mass Screening; D008866:Microsurgery / Q000295:instrumentation*; D008875:Middle Aged; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011446:Prospective Studies; D012016:Reference Values