Evaluation of Glucomannan Powder as an Ultrasound Transmission Gel Alternative for Resource-Constrained Environments: A Prospective, Comparative Study.

Introduction: Resource and logistical constraints may limit the availability of commercial ultrasound (US) transmission gel (USTG) in austere environments. Glucomannan powder, a dietary fiber supplement, can be mixed with tap water to form a gel that may be a field-expedient substitute for USTG. We compared glucomannan gel with a commercial USTG for US image adequacy and quality.

Methods: A single clinician obtained 193 US video clips from 14 different examinations on live-tissue and simulation training models using both commercial and glucomannan USTGs. Four US fellowship-trained providers, blinded to type of gel used, independently reviewed the randomized US video clips. The primary outcome of US image adequacy was scored as "yes" or "no" and analyzed using Pearson χ analysis. The secondary outcome of image quality was rated on a 0 to 5 Likert scale and analyzed with the independent t test.

Results: For US image adequacy, commercial USTG was superior to glucomannan gel (P=0.042, 95% CI: 96.5-96.6%), with commercial USTG adequate in 96.6% of images (375 of 388 "yes"), whereas glucomannan USTG was adequate in 93.5% (359 of 384 "yes") of images. For US image quality there was no statistically significant difference between the 2 USTGs (P=0.176, 95% CI: 93.4-93.5%), with commercial USTG rated at 3.4±1.0 and glucomannan gel at 3.3±1.1.

Conclusion: Despite a high image adequacy rate, glucomannan gel proved inferior to commercial USTG for US image adequacy but produced equivalent image quality. Glucomannan USTG may be a reasonable substitute when commercial USTG is unavailable.