Comparison of the ‘sniffing the morning air’ position and simple head extension for glottic visualization during direct laryngoscopy

Background: This was a prospective randomized single-blinded clinical trial comparing the glottic views obtained during direct laryngoscopy between the ‘sniffing the morning air’ position and simple head extension. Methods: A sample of 378 patients, aged 18 to 75 years old with ASA physical status I or II, scheduled for elective surgery under general anesthesia with endotracheal intubation, were randomized into 2 groups. Group A used the sniffing position during the first laryngoscopy while Group B was put in simple head extension position. Positions were then interchanged for the second laryngoscopy. Sniffing position was obtained by placing a 7 cm height non-compressible cushion under the patient’s head. In simple head extension, patient’s head was placed flat. Glottic visualization was assessed based on the Cormack Lehane scale. Intubation was performed after second laryngoscopy and success rate of first attempt intubation was compared. Results: The distribution of patients with different Cormack Lehane scores between the two intubation positions were significantly different (p 0.001). Changing over to the ‘Sniffing position’ resulted in improvement of the Cormack Lehane scores in 109 (57.7%) patients, no change in 75 (39.7%) or worsening in 5 (4.8%) patients. Successful intubation at first attempt was better (p 0.05) with Group A: 156 (83.5%) while Group B: 121 (64.0%). Conclusion: sniffing position provided better glottic visualization score and increased the successful rate of intubation as compared to simple head extension.