A reply

Abstract

We would like to thank Drs Belagodu and Kessell for their comments. We agree that our patient selection criteria probably over-identified difficult intubations. Previous difficult intubation has a better positive predictive value (69–78%) than other independent predictive factors. It means that two to three of the nine patients included in the study could not have been really difficult to intubate. We routinely use the Arné Score that has been accepted by our local Society (Societat Catalana d’Anestesiologia, Reanimació i Terapeùtica del dolor, SCARTD) [1]. This test explores difficult intubation (defined as the need for special techniques additional to Macintosh laryngoscopy to intubate the trachea), instead of difficult laryngoscopy alone. It has a better likelihood ratio than Wilson or El Ganzouri tests. Patients with an Arné score ≥ 11, compared to El Ganzouri score ≥ 4 or Wilson score ≥ 4, have the highest probability of being difficult to intubate when the test is positive. The El Ganzouri simplified test has a specifity of 93.8% and sensitivity 64.5% for predicting difficult laryngoscopy in general surgery patients, that is a likelihood ratio of 11 and a probability of a difficult laryngoscopy when the test is positive of around 21%. The Arné test has a 94% specificity and 96% sensitivity for predicting difficult intubation, that is a likelihood ratio of 16 and a probability of a difficult intubation when the test is positive around 25%. The combination of remifentanil, midazolam and topical anaesthesia caused loss of muscle tone and mild airway obstruction in some patients while unstimulated, which may explain the low oxygen saturation before starting the procedure. Respiratory rate was kept above 8 breaths.min−1 by maintaining verbal contact and adjusting the remifentanil infusion. The patients were interviewed the following day after by the authors, which may be an important bias. However, awake intubation requires a climate of confidence and good communication with the patient. We constantly encourage patients to report any discomfort or unpleasant feelings. As patients are concerned about future intubation, we think they would not hesitate to report unpleasant recall. When deciding whether or not to perform awake intubation in patients with low positive scores of difficult intubation prediction, we also take into account further relevant information for patient safety, such as the predicted difficult mask ventilation score [2]. For that reason, we considered the term ‘difficult airway’ more appropriate than ‘difficult intubation’ for the study title.