Introduction:
Classical teaching in laryngoscopy advocates the use of Miller (Straight) blades to be placed underneath the epiglottis and lift it, whereas for Macintosh (Curved) blades the tip is positioned in the vallecula. Published studies in anesthesia suggest that straight blade positioning in the vallecula may be a satisfactory technique for small children. However, there is no clear evidence of consistent implementation of this methodology in practice and associated intubation success.
Objectives:
To assess laryngoscope blade tip position during pediatric tracheal intubation in the emergency department (ED) and its association with intubation success and time of laryngoscopy.
Methods:
Single center retrospective observational cohort study. Children undergoing tracheal intubation in a tertiary pediatric ED under video-recorded conditions were eligible for inclusion. A CMAC video laryngoscope was used as first line device with the video feed recorded for review. Videos were reviewed and the blade tip position during intubation recorded by study personnel. Blade tip position was categorized as ‘Correct’ if the curved blade was in the vallecula or straight blade was lifting the epiglottis; otherwise the position was categorized as ‘Incorrect’. Time of laryngoscopy was defined as time from blade insertion to removal. Univariate analysis between covariates was done by Fisher’s exact testing for intubation success and by nonparametric methods for laryngoscopy time.
Results:
A total of 17 complete videos were included in the study. Mac blade was used correctly in 8/10 cases (80%); Miller was used correctly in 1/7 cases (14%). Among infants (≤ 12 months), the Miller was used incorrectly in 3/4 cases (75%). Intubation was successful in 9/9 cases (100%) with correct blade position and in 5/8 cases (63%) with incorrect position (p=0.04). There was no significant difference in mean calculated laryngoscopy time for correct versus incorrect blade tip position (37.90 ± 26.80 sec vs. 44.33± 15.22 sec, p=0.12)
Conclusion:
Correct position of the laryngoscope blade tip is associated with higher intubation success. There was no significant difference in the laryngoscopy time for both correct and incorrect blade position.
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