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October 22, 2008
9:00 AM - 11:00 AM
Room Hall E2-Area D,
TSE "Mask" Improves Oxygenation and Prevents Desaturation in Sedated High-Risk Patients during TEE
James Tse, Ph.D., M.D., Sylviana Barsoum, M.D., Maria Negron, M.D., Howard Chen, M.D., Shaul Cohen, M.D.
Anesthesia, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ
INTRODUCTION: Most patients undergoing transesophageal echocardiography (TEE) outside OR receive topical anesthesia, sedation and O2 via nasal cannula (NC). However, even light sedation may cause desaturation in patients with severe cardiopulmonary diseases. A NC provides inadequate O2 when the mouth is kept open with a bite block. A plastic sheet (TSE "Mask") has been shown to convert an ineffective NC into an effective face tent1-2. It improves oxygenation and reduces the need for assisted ventilation in deeply sedated patients during upper endoscopy2. We studied whether it improved oxygenation in high-risk patients during TEE.

METHODS: This is a retrospective review of nursing records at our Echo Lab (9/07–1/08). Patients received topical anesthesia (15 cc viscous lidocaine and benzocaine spray x 3) and NC O2 (5 l/min). Midazolam (0.5-4 mg) and/or meperidine (12.5-50 mg) were titrated by cardiologists to achieve adequate sedation prior to TEE probe insertion. A TSE "Mask" was prepared using a clean clear specimen bag to cover patient's nose and mouth1-2. Patients were separated into 3 groups (G). G1 (n=81) received only NC O2 throughout the case. G2 (n=20) initially received NC O2 , developed desaturation with sedation and a TSE "Mask" was then applied to the patient for the rest of the case. G3 (n=24) received NC O2 with a TSE "Mask" throughout the case. The paired and unpaired Student's t-tests were used. A p value <0.05 is considered as statistically significant. Data are Mean±S.E.

RESULTS: There were no differences among groups in the dosages (ug/kg) of midazolam (G1:32±2; G2:25±2; G3:26±3) or meperidine (G1:325±33; G2:306±52; G3:235±50). G1 had a RA O2 Sat of 97.3±0.2% that was increased to 99.2±0.1% and maitained at 98.9±0.2% with NC O2.[table1]G2 had a lower RA O2 Sat (95.1±0.6%) than that of G1. It was increased to 97.2±0.4% with NC O2. These patients experienced desaturation (92.7±0.6%) with sedation. Their oxygenation was improved and maintained (97.5±0.5%) with a TSE "Mask" for the rest of the case. G3 patients had a lower RA O2 Sat (92.4±0.7%) than those of G1 and 2. It was increased to 95.6±0.6% by NC O2 . Their oxygenation was further improved (97.9±0.4%) and maintained throughout sedation and the procedure (97.8±0.4%) with a TSE "Mask" .

CONCLUSION: The data show that a TSE "Mask" improves oxygenation and prevents desaturation in sedated high-risk patients during TEE. This technically simple and effective face tent may improve patient safety at no cost and should be routinely used during TEE.

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

Anesthesiology 2008; 109 A1723
Table 1. Effects of TSE "Mask" on Oxygen Saturation in Sedated Patients during TEE
O2 SaturationBaseline RANC (5l O2/min)NC Pre-TMNC+TMAfter TEE InsertionPrior to R/O TEE
Group 1 (n=81)97.3±0.2%99.2±0.1%*N/AN/A98.9±0.2%*98.9±0.2%*
Group 2 (n=20)95.1±0.6%α97.2±0.4%*α92.7±0.6%#97.5±0.5%*δ97.5±0.6%*δ97.5±0.7%*δ
Group 3 (n=24)92.4±0.7%αβ95.6±0.6%* αβ(n=18)N/A97.9±0.4%*#97.8±0.4%*#97.6±0.5%*#
RA; Room Air; NC: Nasal Cannula; TM: TSE "Mask"; R/O: removal of; N/A: Not Applicable. *Significantly different from RA, p<0.01. #Significantly different from NC, p<0.01. αSignificantly different from Group 1, p<0.0001. βSignificantly different from Group 2, p<0.04. δSignificantly different from Pre-TSE "Mask", p<0.0001.