Supervisors info:
Κουσκούνη Ευαγγελία, Αναπληρώτρια Καθηγήτρια, Ιατρική, ΕΚΠΑ
Παπαδημητρίου Λίλα, Αναπληρώτρια Καθηγήτρια, Ιατρική, ΕΚΠΑ
Ξάνθος Θεόδωρος, Καθηγητής, Ιατρική Σχολή, Ευρωπαικού Πανεπιστημίου Κύπρου
Summary:
The aim of the study was to determine which patients, according to the pre-anaesthetic airway assessment, are benefit by using the McCoy laryngoscope, so in case of difficult airway management any delay would be avoided. Recording the patients’ features in cases that the McCoy laryngoscope didn’t prove helpful, would also be usefull.
Fifty patients requiring tracheal intubation for elective surgery were enrolled into the study. The patients of the study were submitted to general, urology, thoracic, ORL, gynecology and vascular syrgery at the General Hospital of Athens “Laiko” during 1/2/2016- 30/4/2016, aged 17- 78 years old. For safety reasons, emergency cases and rapid sequence induction (RSI) cases were excluded from this study. The pre- anaesthetic airway features recorded were as followed: Mallampati score, cervical spinal cord mobility, thyromental distance in cm, mouth opening in cm. Patients that were found to be normal in all of the above parameters, were excluded from the study. After receiving general anaesthesia, each patient was submitted to laryngcoscopy with the McCoy laryngoscope first in its neutral position and afterwards in elevated position. The McCoy laryngoscope was considered equal to the McIntosh when using in neutral position. After laryngoscopy, the view of the larynx with both methods was recorded according to the Cormack- Lehane classification.
54% of the study’s smaple seemed to have improvement of the laryngoscopic view after using the McCoy, which was statistically significant (p-value<0,001). It seemed that McCoy didn’t improve the laryngoscopic view with regards to high Cormack- Lehane classes (III- IV) and further intubation tools were needed (boogie, stylet, Glidescope). Also, in some patients the laryngoscopic view was improved, however, it didn’t became “easy”, as it was set in the current study. As far as pre- anaesthetic features related to difficult intubation are concerned, only Mallampati score was significantly related to laryngoscopic view (using the McCoy). However, it seemed that Mallampati score wasn’t related to laryngoscope view’s improvement after using the two blades. Patients that seemed to have improved view of the larynx after using the McCoy, had more often limited cervical spinal cord mobility and low thyromental distance.
As a result, we expect laryngoscopic view improvement after using the McCoy, in patients with limited cervical spinal cord mobility and/or low thyromental distance but not in those with high Mallampati score. However, according to Cook et al, the McCoy in its neutral position and the McIntosh are not equal, as it seemed that the McCoy tends to provide a worse laryngoscopic view related to the McIntosh when the airway is not difficult. If a simple device improves the laryngeal view in cases where the laryngeal view is restricted, it should be available as an aid to intubation. In order for it to be recommended as the first choice laryngoscope such a device should not make easy intubations difficult. As a result, it is suggested that for routine laryngoscopy the McIntosh blade may be the better tool. On the other hand, McCoy blade should always be available in cases of airway management, as it may improve laryngeal view in patients with limited cervical spinal cord mobility and low thyromental distance.
Keywords:
Equipment, Laryngoscope, McCoy, McIntosh,
Anaesthesia, Laryngoscopy, Intubation,
Difficulty
