Comparison of Bed up Head Elevated Position With Sniffing Position in Rapid Sequence Induction.

This study is aimed to conduct a randomised controlled trial comparing endotracheal intubation (ETI) in bed up head elevation BUHE position versus sniffing position in simulated rapid sequence induction (RSI).

Objective is to determine if the time taken for intubation in the bed up head elevated position is non-inferior to time taken for intubation in the sniffing position.

The hypotheses:

1. In patients undergoing rapid sequence induction in simulated emergency surgery under general anaesthesia, direct laryngoscopy (DL) and ETI in the BUHE position is non inferior to time required for DL and successful ETI in the sniffing position.
2. In patients undergoing rapid sequence induction in simulated emergency surgery under general anaesthesia, direct laryngoscopy (DL) and ETI in the BUHE position improve POGO score.
3. In patients undergoing rapid sequence induction in simulated emergency surgery under general anaesthesia, direct laryngoscopy (DL) and ETI in the BUHE position reduces airway related complications.

Terminology:

Direct laryngoscopy (DL) and Endotracheal intubation (ETI): Is a method of inserting a breathing tube into the trachea (windpipe) once patient undergo general anaesthesia.

Bed up head elevation (BUHE): Bed up at 20-30 degree aiming alignment between the external auditory meatus with sternal notch.

Sniffing position: Maintaining supine position with head elevation with head rest.

Rapid sequence induction (RSI): An established method of inducing anaesthesia in patients who are at risk of aspiration of gastric contents into the lungs. It involves loss of consciousness during cricoid pressure followed by intubation without face mask ventilation. The aim is to intubate the trachea as quickly and as safely as possible.

POGO score: Percentage of glottic opening

Cricoid Pressure (CP): Maneuvre to prevent regurgitation of gastric contents during induction of anaesthesia by temporary occlusion of the upper end of the esophagus by backward pressure of cricoid cartilage against bodies of cervical vertebrae.

All patients from age 18 years old to 75 years old undergoing elective surgery under general anaesthesia in operating theater of University Malaya Medical Centre over a period of 15 months, from April 2018 to June 2019 will be included and recruited based on inclusion and exclusion criteria.

Those patient that fulfilled the criteria and consented for the study will be randomized to 2 group.

i) BUHE group: Bed up at 20-30 degree aiming alignment between the external auditory meatus with sternal notch.

ii) Sniffing group: Maintaining supine position with head elevation with head rest (foam donut).

Induction of anaesthesia starts with:

* preoxygenation with 100% oxygen for 3-5 min performed until end tidal oxygen of 85% achieved.
* A pre-calculated dose of induction agent is administered, followed immediately by a neuromuscular blocking agent.

(IV Fentanyl 2mcg/kg,IV Propofol 2-3mg/kg,IV Rocuronium 1mg/kg).

* Cricoid pressure at 10 Newton is applied increasing to 30 Newton once consciousness is lost.
* After adequate neuromuscular blockade,both group patients will be intubated by one investigator via direct laryngoscopy using Macintosh blade size 3 or 4.
* Time taken from insertion of Macintosh blade into oral cavity till confirmation of endotracheal tube placement via detection of CO2 on the end tidal CO2 monitor will be recorded.

Eligibility Criteria:
Inclusion Criteria:

* All patients undergoing elective surgery under general anaesthesia from age 18 years old to 75 years old.

Exclusion Criteria:

* Patients with airway obstruction
* Patients with contraindication to neck extension
* BMI\> 35kg/m2
* Patient with history of difficult airway from previous intubation history
* Only single intubation will be included if patients had multiple surgery during their hospital stay
* Patients with ischaemic heart disease, cerebrovascular diseases and respiratory disease