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.