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October 13, 2012
8:00:00 AM - 11:00:00 AM
Room Hall C-Area B
Is No-Cost TSE “Mask” More Efficient Than High Nasal Cannula Oxygen Flow in Reducing Severe Desaturation in Patients Under Deep Propofol Sedation during Colonoscopy?
James T. Tse, M.D.,Ph.D., Shaul Cohen, M.D., May Fernandez, M.D., Kristen Dauphinee, M.D., Sylviana Barsoum, M.D., Mordechai Bermann, M.D., Melissa S. Wu, M.D., Jane Kim, M.D., Candy Anim, M.D., Christine W. Hunter, M.D.
UMDNJ-Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States
Introduction: Patients undergoing colonoscopy routinely receive IV sedation and nasal cannula (NC) O2 at a flow rate of 3-5 l/min. Over-sedation and/or airway obstruction may cause respiratory depression and severe desaturation (Desat). NC O2 flow may be raised in an attempt to improve oxygenation. In severe cases, assisted bag-mask ventilation is needed. A plastic sheet has been shown to improve oxygenation by transforming a NC to a face tent (TSE “Mask”) in deeply sedated patients during upper GI endoscopy in a prospective study1. This technique has been used in Endoscopy Suite. We compared it and high NC O2 flow in reducing severe Desat during colonoscopy.

Methods: Review of patients who underwent colonoscopy identified 2 groups. Group 1 (NC, n=73) received only NC O2. Group 2 (TM, n=142) received NC O2 and a TSE “Mask” using a clean plastic sheet to cover patient's eyes, nose and mouth (Photo)1-3. Patients received NC O2 (3-5 l/min or higher) and only IV propofol. NC patients were separated according to NC O2 flow into NC1 (3-5 l/min, n=41) and NC2 (6-10 l/min, n=32). Student t-test and Chi Square test were used for analysis. A p value <0.05 was considered as significant. (Mean±S.D.)

Results: There were no differences in age (All: 56±15), propofol dose (NC1: 217±89 mcg/kg/min; NC2: 207±49 ; TM:219±86) and duration (NC1: 24±13 min; NC2: 26±11 ; TM: 26±13).

There were significant differences in ASA Status (NC1: 2 ASA III/39 vs NC2: 9 ASAIII/30 & TM: 41 ASAIII-IV/136, p<0.01), BMI (NC1: 26±4 kg/m2 vs NC2: 28±5 & TM: 28±7, p<0.05), the highest NC O2 flow (NC1: 4.0±0.6 l/min; NC2: 6.8±1.3; TM: 4.5±1.1, p<0.005), room air O2 Sat (NC1: 99±1% vs. NC2: 98±1% & TM:98±2%, p<0.05), and O2 Sat after 5 min pre-oxygenation (NC1: 99±3% & NC2: 99±2% vs TM: 100±1%, p<0.01), lowest O2 Sat (NC1: 94±7% & NC2: 92±7% vs TM: 98±4%, p<0.0001) (Fig 1), severe Desat (O2 Sat≤85%) (NC1: 3/41 & NC2: 5/32 vs TM: 1/142) (Fig 2) and bag-mask ventilation (NC1: 0/41; NC2: 2/32 vs TM: 1/142, p<0.05).

Nine NC1 patients had severe Desat (O2 Sat: 86±9%) and their NCs were converted to TMs. O2 Sat was improved to 99±1%, 99±2% and 99±1% at 5 min intervals (p<0.002). Six NC2 patients had severe Desat (O2 Sat: 86±3%) and their NCs were converted to TMs. O2 Sat was improved to 96±4%, 98±3% and 98±1% at 5 min intervals (p<0.001.

TM patients had higher FiO2 (0.76±0.14, p<0.0001) than CN1 (0.31±0.09) and CN2 (0.38±0.28).

Conclusion: Data show that TSE “Mask” is more efficient than high NC O2 flow in reducing severe desaturation and bag-mask ventilation in patients under deep propofol sedation during colonoscopy. This face tent takes a few seconds to prepare at no cost and may improve patient safety. Although it can be used as a rescue device when patient’s oxygenation deteriorates, it should be routinely used prior to sedation during colonoscopy.

Ref: 1. Anesth 107:A922, 2007; 2. Anesth 102:484, 2005; 3. www.TSEMask
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