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October 16, 2011
8:00:00 AM - 11:00:00 AM
Room Hall B2 Area E
A Simple Technique to Improve Oxygenation and Prevent Severe Desaturation in Patients under Deep Propofol Sedation during Short Colonoscopy
James T. Tse, M.D.,Ph.D., Leigh Nelson-Lane, M.D., Shruti Shah, M.D., May Anne Fernandez, M.D., Shaul Cohen, M.D.
UMDNJ-Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States

Patients routinely receive nasal cannula (NC) O2 and IV sedation during colonoscopy. Over-sedation and/or airway obstruction may cause desaturation (Desat). A simple plastic sheet was shown to improve oxygenation in deeply sedated patients by transforming NC to a face tent (TSE "Mask") during lengthy upper GI endoscopy1. We examined its effectiveness in improving oxygenation during short colonoscopy.

This retrospective review of patients who underwent colonoscopy identified 2 groups. Group 1 (NC, n=65) received NC O2. Group 2 (TM, n=256) received NC O2 and a TSE "Mask" using a clean plastic specimen bag to cover patient's eyes, nose and mouth(Photo)1-3. Patients received NC O2 (3-5 l/min) and only IV propofol. Student t-test and Chi Square test were used for analysis. A p value <0.05 was considered as significant. (Mean±S.D.)

Among patients who underwent short colonoscopy (≤20 min), there were no differences in procedure duration (NC:15±4 min; TM:16±4), age (NC:61±17 yrs; TM:57±16), BMI (NC:27±4; TM:28±7), ASA Physical Status (ASA) (NC:2.0±0.7; TM:2.2±0.7) and overall propofol dosage (NC:229±61 ug/kg/min; TM:243±96). There were differences in room air (RA) O2 Sat (NC:99±1%; TM:98±2%), NC O2 flow (NC:5.5±1.9 l/min; TM:4.6±1.3), FiO2 (NC:0.35±0.21; TM:0.75±0.16), lowest O2 Sat (NC:92±8%; TM:98±3%)(Fig. 1), severe Desat (O2 Sat ≤85%) (NC:5/28; TM:0/102)(Fig. 2) and assisted bag-mask ventilation (NC: 2/28; TM: 0/102). Six NC patients had severe Desat (O2 Sat: 83±10%) and TM was then added. O2 Sat was improved to 98±1%, 99±2% and 99±2% at 5-min intervals.

Among patients who underwent lengthy colonoscopy (>20 min), there were no differences in duration (NC:32±11 min; TM:34±11), age (NC:53±14 yrs; TM:55±13), ASA (NC: 2.0±0.6; TM:2.2±0.7), BMI (NC:28±5; TM:28±6), propofol dosage (194±60 ug/kg/min) and bag-mask ventilation (NC:1/37; TM:1/154). There were differences in RA O2 Sat (NC:99±1%; TM:98±2%), NC O2 flow (NC:5.3±1.8 l/min; TM:4.4±1.1), FiO2 (NC:0.28±0.09; TM:0.73±0.16), lowest O2 Sat (NC:93±6%; TM:97±4%) and severe Desat (O2 Sat ≤85%) (NC:5/37; TM:1/154). Eight NC patients had severe Desat (O2 Sat: 86±5%) and TM was added. O2 Sat was improved to 97±4%, 98±3% and 98±1% at 5-min intervals.

Discussion: Data show that TSE "Mask" improves oxygenation and reduces severe desaturation in deeply sedated patients during short and long colonoscopy. It also reduces the need for assisted ventilation during short colonoscopy. This face tent takes only a few seconds to prepare and increases FiO2 without raising O2 flow. It may improve patient safety and reduce procedure interruptions and healthcare costs. Although TSE "Mask" can be used as a rescue device, it should be used prior to sedation even during short colonoscopy.

1. Anesth 107:A922, 2007. 2. Anesth 102:484, 2005. 3.
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