Patients undergoing emergency surgery can have both anatomical and physiological difficult airways.[1] Such airways have substantial risk of aspiration (1 in 895 patients undergoing emergency surgery) due to delayed gastric emptying and difficult / failed intubation (1 in 50-100).2, 3 The propensity for hypoxemia due to underlying pathological condition and reduced physiologic reserves can lead to potentially preventable adverse events that increase the morbidity and mortality.[4] The aim of any attending anaesthesiologist while intubating a patient for emergency surgical procedure is always to intubate the trachea in the first attempt.

Rapid sequence intubation (RSI) is the gold standard technique for intubating trachea in patients undergoing emergency surgery.[5] Emergency intubation carries a higher risk of complications than elective intubation.[6] Difficulty during tracheal intubation can cause a prolonged apnoea time which may cause a sudden reduction in pH, haemodynamic collapse, dysrhythmia, and bradycardia.[7] Increased number of laryngoscopic attempts is associated with significant increase in airway related complications and contributes to patient morbidity.[8] According to DEVICE trial, videolaryngoscopy has higher first-attempt rate of successful intubation compared to direct laryngoscopy (DL) in critically ill adults in emergency department and intensive care unit.[1] Haemodynamic stress response is less with VL since it requires a lifting force of 5-14 Newton (N) as compared to DL which requires 35- 40 N force to visualize the glottis. As a result, during videolaryngoscopy oesophageal entrance would be opened less and cricoid pressure of 30 N would become more effective.[4]

King Vision™ videolaryngoscope (KVVL, King Systems, Nobleville, IN, USA), a portable laryngoscope provides glottic visualization on a video camera with a built-in monitor. This device has two anatomically shaped ( hyperangulated ≅90°) blades with or without tube guide and with or without required preshaped stylet.[9] The non channelled (NC) blade allows control over movements and trajectory of the ETT with a 60° angled stylet. The channelled (CH) blade provides a dedicated passage for ETT and is bulkier compared to NC blade. When the glottic opening is seen in the center of video image, the ETT is advanced forward and should enter the airway without necessity of being separately steered. Minimum mouth opening required for NC and CH blades is 13mm and 18 mm respectively.[10] This study was planned to assess the clinical performance of the two blades of KVVL in patients undergoing emergency surgery under GA. We hypothesized that the CH blade is associated with faster intubation and has higher success rate of first pass intubation. The primary outcome was to determine the time required for tracheal intubation (TTI). The secondary aim was to determine ease and success of intubation, haemodynamics and complications.