Update Mallampati : Theoretical and practical knowledge of European anesthetists on basic evaluation of airways

Abstract

In 1985 Mallampati et al. published anon-invasive score for the evaluation of airways (Mallampati grading scale, MGS), which originally consisted of only three different classes and has been modified several times. At present it is mostly used in the version of Samsoon and Young consisting of four different classes. ClassI: soft palate, fauces, uvula, palatopharyngeal arch visible, classII: soft palate, fauces, uvula visible, classIII: soft palate, base of the uvula visible and classIV: soft palate not visible. Nevertheless, other versions of MGS still exist, each having different values for sensitivity and specification. The current opinion is therefore that MGS is no longer useful as a stand-alone predictor but in combination with others it is still part of today's most relevant guidelines, such as those of the American Society of Anesthesiologists (ASA), the UK's Difficult Airway Society (DAS), the European Society of Anaesthesiology (ESA) and the German Society for Anesthesiology and Intensive Care Medicine (DGAI) and must therefore be known by anesthetists. Even in times of sophisticated tools for airway management, the procedure remains ahigh risk, so every anesthetist has to be prepared for and well trained in management of known and unexpected difficult airways. Evaluation of the patient's airway is apart of modern airway management to prevent problems and reduce risk of hypoxia during the procedure. The theoretical knowledge and practical skills of European anesthetists were evaluated at two international congresses, the German Anesthesia Congress (DAC) and Euroanaesthesia 2014. The DAC is an annual meeting of German speaking anesthetists, hosted by the DGAI. The Euroanaesthesia is the annual European pendant hosted by the ESA. Participation was voluntary and only physicians were allowed to take part. Theory was evaluated by aquestionnaire containing open and closed questions for MGS that had to be answered by every participant alone. Apart from theory, a practical evaluation was performed. Every participant had to classify the MGS of ahuman airway model. The model was identical on both congresses. According to the original publication achecklist containing the factors essential for the correct performance was filled out by asupervising experienced anesthetist. During DAC 2014 n = 267 physicians participated in the study, 22 participants were excluded due to inconsistent answers, incomplete questionnaires or missing practical part. A total of 245 data sets were evaluated. During Euroanaesthesia 2014 n = 298 physicians participated in the study, 68 participants were excluded due to inconsistent answers, incomplete questionnaires or missing practical part and 230 data sets were evaluated. At the DAC the mean age (± SD) was 44.5 ± 9.5 years, 157 (64.1%) were male and 88 (35.9%) were female. Working experience was trainee anesthetist in 16.7% and other participants were experienced anesthetists. At the ESA the mean age (± SD) was 42.4 ± 9.5 years, 133 (57.8%) were male and 97 (42.2%) female. Trainee anesthetists were 15.2%, the rest were experienced anesthetists. The DAC participants knew Mallampati classes1 (65%) and4 (45%) better than2 and3 and there was no relevant differences to the ESA (close to 30% knew the classes1-4 here). Classification of the airway model was correct in 62% and 67% at DAC and ESA, respectively. Most participants performed the practical evaluation correctly except the sitting position of the model. In agreement with earlier studies, these results show the lack of knowledge in evaluation of airways according to current guidelines of all relevant societies. This is likely to increase preventable risks for patients as unexpected difficult airway management increases the risk for hypoxia and intubation damage.