Hypoxia is the most common adverse event in gastrointestinal endoscopes sedated with propofol and sufentanil, especially in elderly people. The aim of this randomized study was to determine whether intervention based on additional capnographic monitoring reduces the incidence of hypoxia in gastrointestinal endoscopes procedures for elderly patients.

Inclusion Criteria:

• 65 ≤ Age <80
• patients undergoing gastrointestinal endoscopes
• patients signed informed consent form
• ASA classification I-II

Exclusion Criteria:

• Coagulation disorders or a tendency of nose bleeding
• An episode/exacerbation of congestive heart failure (CHF) that requires a change in medication, diet or hospitalization from any cause in the last 6 months
• Severe aortic stenosis or mitral stenosis
• Cardiac surgery involving thoracotomy (e.g., coronary artery bypass graft (CABG), valve replacement surgery) in the last 6 months
• Acute myocardial infarction in the last 6 months
• Acute arrhythmia (including any tachycardia - or bradycardia) with the fluid of hemodynamics instability
• Diagnosed chronic obstructive pulmonary disease or current other acute or chronic lung disease requiring supplemental chronic or intermittent oxygen therapy)
• Pre-existing bradycardia (heart rate < 50 / min), or hypoxia (SaO2< 90 % )
• Need supplemental oxygen because of pre-existing diseases
• Emergency procedure or surgery
• Multiple trauma
• Upper respiratory tract infection
• Allergy to propofol or tape and adhesives