Please select the eligibility criteria that correspond to the clinical trial below.
Title: Comparison of Bed up Head Elevated Intubation Position With Glidescope Assisted Tracheal Intubation: A Randomised, Controlled, Non-inferiority Trial
Brief Summary: Positioning during the process of tracheal intubation is critical, as optimal positioning can greatly facilitate successful intubation. Many complications can occur as a result of failed intubation, ranging from airway injury, lack of oxygen, with even deaths. Today, the most popular positioning of patients for intubation is in the "sniffing" position. There is however evidence to support that intubation in the bed-up-head-elevated position may be better. In today's technological age, video assisted laryngoscopy (Laryngoscopy is the process of visualizing the vocal cords prior to intubation), a new method where the anaesthetist intubates a patient via aid of an image guided view of the airway, is increasingly popular due to its reliability and superiority to normal intubation. However, it is not widely available, and may suffer from technical breakdowns. The Glidescope is one example of a video laryngoscope, and has been widely researched in the medical literature. In this study, the investigators wish to investigate whether intubation in the bed-up-head-elevated position will be as good as, if not better than Glidescope assisted tracheal intubation, in patients undergoing elective surgery and planned for general anaesthesia.


Options:
A: Inclusion Criteria:

The patients who will undergo general anesthesia for abdominal surgery, American Society of Anesthesiologists physical status I to III, The patients who were aged between 20 and 75

Exclusion Criteria:

Our exclusion criteria were to have a history of emergency intubation or a difficult intubation, to have a body mass index higher than 35 or a rheumatologic disease that cause limitation of cervical motion, to have a previous history of cervical operation or tumor, trauma or infection on upper airway, and to have no tooth.
B: Inclusion Criteria:

* Any patient over the age of 16 years, requiring urgent (within 30 minutes) endotracheal intubation, who are attended to by the critical care team will be eligible for enrolment

Exclusion Criteria:

* Patients who require intubation within 5 minutes or have contraindications to either of the study intubation technique will be ineligible
* cardiac arrest
* cardiopulmonary instability (oxygen saturation \<90% or systolic blood pressure \< 80 mmHg despite oxygen or fluid therapy)
* any clinical deterioration while awaiting randomization
* known prior or anticipated difficult intubation
* need for awake intubation (defined by sedation, topicalization and avoidance of neuromuscular blockade)
* pregnancy
* cervical spine precautions
* any patient deemed inappropriate for enrolment by the attending physician
C: Inclusion Criteria:

1. Patients undergoing elective surgeries under general anaesthesia
2. Patients aged from 18 years old to 75 years old
3. Patients who are able to give informed consent

Exclusion Criteria:

1. Patients with airway obstruction
2. Patients with contraindications to neck extension
3. Patients with small mouth opening (\<3 cm)
4. BMI \> 35 kg/m3
5. Patients with ischemic heart disease, cerebrovascular disease and respiratory diseases
6. Patients in whom rapid sequence induction is indicated
D: Inclusion Criteria:

* age \> 18years
* elective surgery
* single lumen endotracheal intubation required
* signed informed consent
* one risk factor for a difficult laryngoscopy ( Mallampati score \>3, inter-incisor gap \< 3.5cm, thyromental distance \< 6.5cm, sternomental distance \< 12.5cm, reduced neck extension and flexion)

Exclusion Criteria:

* lack of patient consent
* anesthesiologist declines to consent
* contraindication to neuromuscular blockade
* ASA 4
* rapid sequence intubation
* previous failed intubation
* other method of intubation indicated eg fiberoptic intubation, awake tracheostomy
* symptomatic gastro-esophageal reflux
* cervical spine instability
* unstable hypertension and symptomatic coronary artery disease
* cerebrovascular disease or raised intracranial pressure
* oral/pharyngeal/laryngeal carcinoma
* loose teeth/poor dentition

Answer: C