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October 18, 2010
9:00:00 AM - 11:00:00 AM
Room Hall B1-Area B
TSE "Mask" Prevents Severe Desaturation in Propofol-Sedated Obese Patients during Upper GI Endoscopy
  **   John Denny, M.D., Shaul Cohen, M.D., Tejal Mehta, M.D., Mark Fullenkamp, M.D., James Tse, Ph.D., M.D.
Anesthesia, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, New Jersey
Introduction: Patients routinely receive O2 via nasal cannula (NC) and iv propofol during upper GI endoscopy. Over-sedation and/or airway obstruction may cause desaturation (Desat). Obese patients have increased risk of respiratory complication during sedation due to a myriad of factors, such as airway anatomy, sleep apnea, decreased FRC and increased O2 consumption. A plastic sheet (TSE "Mask") has been shown to improve oxygenation in sedated patients during upper endoscopy.1 We wish to confirm its effectiveness in improving oxygenation in obese patients during upper endoscopy.

This retrospective review of patients undergoing EGD, EUS, ERCP, EGD/Colonoscopy or PEG identified 2 groups. Group1 (NC, n=76) received NC O2. Group 2 (TM, n=268) received NC O2 and a TSE "Mask" from the start using a clean plastic specimen bag 1-3 or a plastic fluid-shield surgical mask.3 It covered patient's eyes, nose and mouth. Monitors included ECG, BP cuff, pulse oximetry, capnography and oximetry. Patients received NC O2 (3-5 l/min, or higher) and iv propofol. Data collected included age, weight, height, O2 Sat, assisted ventilation, the amount of propofol, the duration and FiO2. Student t-test and the Chi Square test were used for analysis. A p value <0.05 was considered as significant. (Mean±S.D.)

Results: Among non-obese patients (BMI <30), there were no differences in age (NC: 61±19 yrs; TM: 61±17), BMI (NC: 24.5±3.6; TM: 24.2±3.5), ASA Physical status (NC: 2.2±0.7; TM: 2.3±0.8), room air (RA) O2 Sat (98±2%), duration (NC: 30±19 min; TM: 31±20) and propofol dosage (NC: 206±83 ug/kg/min; TM: 215±94) between groups. There were differences in the highest O2 flow (NC: 5.3±2.4 l/min; TM: 4.6±1.1), O2 Sat after 5 min with O2 (NC: 99±1%; TM: 100±1%), the lowest O2 Sat (NC: 89±11%; TM: 97±3%), severe Desat (O2 Sat ≤85%) (NC: 16/57; TM: 0/182) and assisted ventilation (NC: 7/57; TM: 0/182).[figure1]Among obese patients (BMI>30), there were no differences in age (NC: 57±16 yrs; TM: 59±17), ASA Physical status (NC: 2.3±0.7; TM: 2.5±0.7), RA O2 Sat (97±2%), O2 Sat after 5 min with O2 (99±1%), highest O2 flow (NC: 5.4±1.7 l/min; TM: 5.6±1.8), duration (NC: 25±11 min; TM: 26±17) and propofol dosage (202±61 ug/kg/min; TM: 192±79) between groups. There were differences in BMI (NC: 32.3±2.2; TM: 35.1±5.3), the lowest O2 Sat (NC: 87±14%; TM: 94±6%), severe Desat (O2 Sat ≤85%) (NC: 6/19; TM: 4/86) and assisted ventilation (NC: 4/19; TM: 2/86).

In 28 NC patients, NCs were converted to TSE "Masks" due to Desat (Lowest O2 Sat: Non-Obese: 81±11%; Obese: 78±16%). O2 Sat was greatly improved 5 and 10 min after adding TM (Non-Obese: 92±6%, 95±4%; Obese: 95±5%, 97±4%).

FiO2 was higher in TM patients (0.49±0.13) than NC patients (0.30±0.08).

: Data show that TSE "Mask" improves oxygenation and prevents severe desaturation in non-obese and obese patients during upper endoscopy. It may have great impact on patient safety in obese patients and should be used routinely during upper endoscopy.

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

From Proceedings of the 2010 Annual Meeting of the American Society Anesthesiologists.
Figure 1