Comparative evaluation of laryngeal view and intubating conditions in two laryngoscopy positions-attained by conventional 7 cm head raise and that attained by horizontal alignment of external auditory meatus - sternal notch line – using an inflatable pillow - A prospective randomised cross-over trial

Abstract

Background and Aims:We compared the laryngoscopy position attained by a 7-cm-high pillow (Sniffing position-SP) with that attained by horizontal alignment of external auditory meatus-sternal notch (AM-S) line-using variable height inflatable pillow.Material and Methods:This prospective-randomised-cross-over study included 50 patients in each group. Group-AM-S: A 7 cm uncompressible pillow was used for attaining first laryngoscopy position, followed by horizontal alignment of external auditory meatus-sternal notch (AM-S) line-using an inflatable pillow for attaining second laryngoscopy position followed by intubation. Group-SP: Horizontal alignment of external auditory meatus-sternal notch (AM-S) line-was done using an inflatable pillow for attaining first laryngoscopy position, followed by using 7 cm uncompressible pillow for second laryngoscopy position followed by intubation. The CL-grade, Intubation Difficulty Score (IDS) and time to intubation were compared in both positions. The head raise (in cm) required for attaining AM-S alignment was noted.Results:CL-grade-I was obtained in significantly larger number of patients with AM-S alignment position than with 7 cm head raise (P = 0.004). CL-grade-III was obtained in significantly lesser number of patients with AM-S alignment (P = 0.002). Mean IDS with AM-S alignment (1.18 ± 1.69) was significantly less than with 7cm head raise (2 ± 1.59; P = 0.007) and time to intubation with AM-S alignment (17.33 ± 4.52 s) was significantly less than that with 7cm head raise (18.94 ± 4.64 s; P = 0.041). The mean head rise required to achieve AM-S line alignment was 4.920 ± 1.460 cm.Conclusion:External Auditory Meatus-Sternal notch (AM-S) line alignment provides better laryngeal view, better intubating conditions and requires lesser time to intubate as compared to a conventional 7-cm-head raise. The size of pillow used for head raise should be individualised.

Comparison of intubating conditions in supine (sniffing) and 25° back-up position using channelled and non-channelled video laryngoscopes - A randomised controlled study

“…[ 5 ] compared laryngeal view and intubating conditions in the sniffing position and position acquired by aligning the external auditory meatus and sternal notch horizontally by using an inflatable pillow (AM-S) and found a significant reduction in the intubation difficulty scale with improved Cormack Lehane grading of laryngeal view in the AM-S position using Macintosh laryngoscope. [ 5 ] A study compared sniffing and neutral positions by using channelled (King Vision) and non-channelled (C-MAC) VLS and found comparable mIDS with lower POGO scores by using C-MAC VLS in a neutral position. [ 3 ] According to Tsan et al .,[ 8 ] Macintosh laryngoscopy in the bed-up head elevated position provides a non-inferior laryngeal view to Glidescope laryngoscopy but is superior to the view acquired in the sniffing position among the general population.…”

“…[ 3 4 ] Originally, a 25° backup position was used in obese patients for difficult intubation as administration of oxygen in this position increases the margin of safety for induction of anaesthesia by achieving 23% higher oxygen tension and better intubating conditions with direct laryngoscopy with comfort for the anaesthesiologist. [ 5 6 ]…”

Airway management in hospital. Methodological recommendations of the All-Russian public organization “Federation of Anesthesiologists and Reanimatologists” (third edition)

“…ÿ Применение дополнительных маневров для улучшения визуализации гортани во время прямой ларингоскопии -внешние манипуляции на гортани (BURP-маневр) [274][275][276], придание пациенту «принюхивающегося положения» [277][278][279], придание пациенту с ожирением HELP-позиции (head-elevated laryngoscopy position) [280][281][282][283] или ramped-позиции [284][285][286][287].…”

“…ň Рекомендация 12. В случае неудачи первой попытки прямой ларингоскопии рекомендуется придание пациенту улучшенного Джексоновского положения (HELP-позиции и иных рекомендованных), применение BURP-маневра [274][275][276][277][278][279][280][281][282][283][284][285][286][287] (УДД -3, УУР -В).…”

A comparative evaluation of the sniffing, the simple head extension and the head hyperextension positions for laryngoscopic view and intubation difficulty in adults undergoing direct laryngoscopy

“…In sniffing position, the neck must be flexed on the chest; typically, by elevating the head with a 7 cm-high ring cushion placed under the occiput and extending the head on the atlanto-occipital joint [ 7 ].…”