title: The efficacy of novel anatomical sites for the assessment of muscle oxygenation during central hypovolemia.
abstract: Muscle tissue oxygenation (SmO2) can track central blood volume loss associated with hemorrhage. Traditional peripheral measurement sites (e.g., forearm) may not be practical due to excessive movement or injury (e.g., amputation). The aim of this study was to evaluate the efficacy of three novel anatomical sites for the assessment of SmO2under progressive central hypovolemia. 10 male volunteers were exposed to stepwise prone lower body negative pressure to decrease central blood volume, while SmO2was assessed at four sites-the traditional site of the flexor carpi ulnaris (ARM), and three novel sites not previously investigated during lower body negative pressure, the deltoid, latissimus dorsi, and trapezius. SmO2at the novel sites was compared to the ARM sensor and to stroke volume responses. A reduction in SmO2was detected by the ARM sensor at the first level of lower body negative pressure (-15 mmHg; P = 0.007), and at -30 (the deltoid), -45 (latissimus dorsi), and -60 mmHg lower body negative pressure (trapezius) at the novel sites (P ≤ 0.04). SmO2responses at all novel sites were correlated with responses at the ARM (R ≥ 0.89), and tracked the reduction in stroke volume (R ≥ 0.87); the latissimus dorsi site exhibited the strongest linear correlations (R ≥ 0.96). Of the novel sensor sites, the latissimus dorsi exhibited the strongest linear associations with SmO2at the ARM, and with reductions in central blood volume. These findings have important implications for detection of hemorrhage in austere environments (e.g., combat) when use of a peripheral sensor may not be ideal, and may facilitate incorporation of these sensors into uniforms.
authors.affiliation: Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
authors.forename: Justin D
authors.initials: JD
authors.lastname: Sprick
authors.affiliation: Sotera Wireless, San Diego, CA 92121, USA.
authors.forename: Babs R
authors.initials: BR
authors.lastname: Soller
authors.affiliation: Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, TX 76107, USA caroline.rickards@unthsc.edu.
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Rickards
mesh_terms: D000328:Adult; D057645:Deltoid Muscle / Q000737:chemistry*; D006470:Hemorrhage / Q000175:diagnosis; D006801:Humans; D020896:Hypovolemia / Q000175:diagnosis* / Q000378:metabolism; D008150:Lower Body Negative Pressure; D008297:Male; D018482:Muscle, Skeletal / Q000737:chemistry*; D010100:Oxygen / Q000032:analysis*; D013318:Stroke Volume; D064171:Superficial Back Muscles / Q000737:chemistry*
chemical_list: D010100:Oxygen
keywords: Trauma; hypovolemia; near infrared spectroscopy; physiologic monitoring; tissue oxygen saturation