A randomised clinical trial comparing the ‘sniffing’ and neutral position using channelled (KingVision^®) and non‐channelled (C‐MAC^®) videolaryngoscopes

Abstract

Head and neck position is one of the factors which can be associated with difficult videolaryngoscopy and tracheal intubation. This prospective randomised clinical trial compared 'sniffing' and neutral positions using a channelled (KingVision ) and a non-channelled (C-MAC D-blade) videolaryngoscope in 200 adult patients randomly allocated into four groups (KingVision 'sniffing', KingVision neutral, C-MAC 'sniffing' and C-MAC neutral). The primary outcome was the ease of tracheal intubation using the modified intubation difficulty scale (mIDS) score. Laryngoscopy time, intubation time, laryngoscopic view using the percentage of glottic opening (POGO) score and success rate of tracheal intubation were secondary outcomes. The median (IQR [range]) modified difficulty scale scores for the four groups, respectively, were 0 (0-1 [0-3]), 0 (0-1 [0-4]), 1 (0-1 [0-5]) and 0 (0-1 [0-3]; p = 0.384). There was no significant difference in laryngoscopy time (p = 0.020), intubation time (p = 0.272) and success rate (p = 0.968) between the groups. The percentage of glottic opening score was lower for C-MAC neutral group as compared with other three groups (p = 0.01). There was no significant difference in the ease of intubation between the 'sniffing' and the neutral position when using the KingVision and the C-MAC videolaryngoscopes. Therefore, either of the two positions could be used with these types of videolaryngoscopes, if deemed advantageous for the patient.

Effect of cricoid pressure on the glottic view and intubation with king vision® video laryngoscope

“…The POGO was lower with C-MAC use in neutral position (median [interquartile range (IQR)] 100 [40–100]) compared to the C-MAC in sniffing position (100 [100–100]) and King vision in sniffing (100 [70–100]) and neutral position (100 [75–100]) with statistical significance ( P = 0.010). [23]…”

“…[31] At the same time, Mendonca et al did not find any significant difference in laryngoscopy time ( P = 0.020), intubation time ( P = 0.272), and success rate ( P = 0.968) with use of KVL or C MAC with the patients in neutral and sniffing position. [23] VL scopy is a dynamic process and changes in the position of the patient's head and neck to suit the need has to be considered during difficult airway situations.…”

Changes in the upper airway following induction of anaesthesia: a prospective observational study protocol to determine the use of ultrasound in the assessment of a difficult airway in China

“…Before (T1) and after anaesthetic induction with loss of consciousness (T2), airway sonographic measurements (Navi series, Shenzhen Wisonic Medical Technologies, Shenzhen, China) will be performed by an attending anaesthesiologist, using a linear ultrasound transducer. Participants will be kept supine, in the sniffing position throughout the measurement procedure 31 32. The probe will be placed in the submental region of the neck, in the midline, to measure the thickness of the anterior cervical soft tissues at five levels (hyoid bone (figure 2A), epiglottis (figure 2B), cricothyroid membrane (figure 2C), thyroid isthmus (figure 2D) and suprasternal notch (figure 2E)) in the axial plane.…”

Hyomental distance measured by ultrasound for size selection of laryngeal mask airway in female patients: a randomized controlled study

“…Preoperative evaluation was performed the day before surgery. After routine fasting (no solids, ≥8 hr; no water, ≥4 hr), patients were sent to operating room (OR) and positioned supine on the operating table with their head in sni ng position [11,12]. Patients were subjected to pulse oximetry, noninvasive blood pressure monitoring (certain patients required invasive arterial monitoring), electrocardiography, and capnography.…”