Predicting Difficult Intubation in Apparently Normal Patients

Abstract

The objective of this study was to systematically determine the diagnostic accuracy of bedside tests for predicting difficult intubation in patients with no airway pathology. Thirty-five studies (50,760 patients) were selected from electronic databases. The overall incidence of difficult intubation was 5.8% (95% confidence interval, 4.5-7.5%). Screening tests included the Mallampati oropharyngeal classification, thyromental distance, sternomental distance, mouth opening, and Wilson risk score. Each test yielded poor to moderate sensitivity (20-62%) and moderate to fair specificity (82-97%). The most useful bedside test for prediction was found to be a combination of the Mallampati classification and thyromental distance (positive likelihood ratio, 9.9; 95% confidence interval, 3.1-31.9). Currently available screening tests for difficult intubation have only poor to moderate discriminative power when used alone. Combinations of tests add some incremental diagnostic value in comparison to the value of each test alone. The clinical value of bedside screening tests for predicting difficult intubation remains limited.

Diagnostic accuracy of anaesthesiologists’ prediction of difficult airway management in daily clinical practice: a cohort study of 188 064 patients registered in the Danish Anaesthesia Database

“…The proportions of difficult tracheal intubation and difficult mask ventilation were low compared with previous studies [8,11,13,25]. This may partly be due to the fact that there is no international consensus on how to define difficult intubation, and it is often equated with, and described by, the laryngoscopic view classified by Cormack and Lehane [26].…”

“…Accurate prediction of difficult airway management may reduce potential complications by allowing the allocation of experienced personnel and the use of relevant equipment [5]. No single predictor of difficult intubation is sufficiently reliable [6][7][8][9][10][11], and metaanalyses have found either none, or only sparse evidence, for a pre-operative assessment based on a single risk factor [6,7,11].…”

Fibreoptic vs videolaryngoscopic (C-MAC®D-BLADE) nasal awake intubation under local anaesthesia

“…Studies on difficult intubations are complicated by the fact that an intubation can be declared as difficult only after the intubation has been attempted [25][26][27][28]. Therefore, random allocation of patients with an even distribution of risk factors for a difficult intubation is crucial for a comparison of different intubation techniques.…”

Management of an Unanticipated Difficult Airway during Emergency “C” Section—A Novel Approach

“…It is higher in obstetric patients than in surgical patients [7] and the incidence in parturients may approach 1 in 500 [8]. Screening tests as Mallampatti oropharyngeal classification, thyromental distance, mouth opening and Wilson risk score yield possible sensitivity (20% -62%) and moderate specificity (82% -97%) [9,10]. One can encounter unanticipated difficult airway with direct laryngoscopy despite the availability of predictive tests [11].…”