[The difficult intubation. The value of BURP and 3 predictive tests of difficult intubation]

The value of BURP (= backwards-upwards-rightwards-pressure of the larynx) was tested as a improvement of the visualisation of the larynx. Simultaneously we wanted to assess the value of different predictive tests of a difficult intubation, which are easy to perform as bedside tests.

1993 patients of all different surgical clinics in a tertiary care hospital in Switzerland were tested, the complete anaesthesiological staff was involved. We registered the original Mallampati classes, the thyromental distances of Patil and Frerk and the difference of the jugulomental distances in maximally reclined and neutral head position according to Chow. Every anaesthetist also noted his personal, subjective opinion of a possible difficult intubation. Under optimal conditions for intubation we assessed the grade of laryngoscopy according to Wilson and applied BURP if the grade was 3 or higher. Both laryngoscopic grades and the difficulty of intubation were noted.

In our study we found 12.5% awkward (Wilson G3-G5) and 4.7% difficult (Wilson G4-G5) laryngoscopies. These could be changed with BURP into 5.0% and 1.9% respectively. With BURP we found 1.8% of difficult intubations. During our study we did not find any patients, whom we could not intubate either with a mandrin inside the tube or with help of the fiberoptic. The relation between sensitivity and specificity was in all single predictors and in two combinations very low. Our personal subjective predictions proofed to be better, but the rate of false negatives was too high for clinical use.

BURP is a valuable method for rendering the majority of difficult laryngoscopies into easy ones. It is very easy to learn and does not need any additional equipment. Three commonly used and recommended predictive tests of the difficult intubation proofed to be of little use in clinical practice.