Ethics approval and consent to participate
The trial was approved by the Human Research Ethics Committee of the Faculty of Medicine of Thammasat University. Because of the sudden and life-threatening nature of cases in patients who needed emergency intubation, the process of obtaining written informed consent was deferred until after the emergency had passed. We sought written informed consent as soon as practicable after the intubation had passed to continue data collection from the patient or, if the patient was unable to give consent, a patient’s legally authorized representative was informed and gave consent for participation in the research. If the patient regain or develop the capacity to consent, then the patient consent was obtained before any further data collection. All experiments were performed in accordance with approved clinical trial protocols and regulations.