Mask adaptor--a novel method of positive pressure ventilation during propofol deep sedation for upper GI endoscopy

Gastrointest Endosc. 2008 Jul;68(1):127-31. doi: 10.1016/j.gie.2007.12.050. Epub 2008 Apr 14.


Background: Propofol dosages required for upper GI endoscopy are often high enough to pose serious risks of respiratory depression. Stopping the procedure and bag ventilating a patient until the propofol wears off may be a safer management because traditional mask ventilation is not available.

Objective: We introduce the mask adaptor for upper GI endoscopy (MAUGE), a new method of positive pressure ventilation during upper GI endoscopy, and assessed its feasibility and safety.

Design: Subjects received propofol 1.5 to 2.5 mg/kg injection followed by repeated doses of 20 to 30 mg if necessary.

Setting: Tertiary hospital.

Patients: Thirty patients, American Society of Anesthesiologists class I to III, undergoing upper GI endoscopy and requesting sedation.

Interventions: After connecting the MAUGE to the anesthetic ventilation circuit and mask, the endoscope was inserted into the patient's digestive tract through the channel for endoscopes in the MAUGE and through the mask. Oxygen was supplied to the respiratory tract through the channel for gas in the MAUGE and through the mask by using positive pressure ventilation by bag-valve-mask ventilation.

Main outcome measurements: Heart rate, noninvasive blood pressure, end-tidal carbon dioxide tension, oxygen saturation, respiratory waveform.

Results: Oxygen saturation was more than 95% throughout the endoscopy in all patients. Positive ventilation was achieved in all patients and consistent with thoracic wall movement and respiratory waveforms shown by capnography.

Limitations: The MAUGE cannot seal the respiratory tract. Patients in high risk for aspiration should not be considered candidates for using the MAUGE.

Conclusions: By use of the MAUGE, positive pressure ventilation was efficaciously achieved, and desaturation and carbon dioxide retention were effectively avoided during the upper GI endoscopy procedure.

MeSH terms

  • Aged
  • Blood Gas Analysis
  • Cohort Studies
  • Conscious Sedation / adverse effects
  • Conscious Sedation / methods*
  • Dose-Response Relationship, Drug
  • Endoscopy, Gastrointestinal / adverse effects
  • Endoscopy, Gastrointestinal / methods*
  • Female
  • Follow-Up Studies
  • Humans
  • Laryngeal Masks
  • Male
  • Middle Aged
  • Positive-Pressure Respiration / instrumentation
  • Positive-Pressure Respiration / methods*
  • Propofol / administration & dosage
  • Propofol / adverse effects*
  • Pulmonary Gas Exchange
  • Respiratory Insufficiency / chemically induced
  • Respiratory Insufficiency / prevention & control*
  • Respiratory Insufficiency / therapy
  • Risk Assessment
  • Sensitivity and Specificity
  • Treatment Outcome


  • Propofol