Pocket mobile smartphone system for the point-of-care submandibular ultrasonography

Background: Focused ultrasonography of the airway may be useful in the prediction of difficult intubation. The wider use of sonography in quantitative airway assessment may depend on the availability of highly portable, inexpensive, and accurate ultrasound systems. Pocket-sized ultrasound devices are emerging as a useful tool for point-of-care ultrasonography. The aim of this study was to evaluate the suprahyoid airway of healthy volunteers using a smartphone-based ultrasound imaging system in comparison with a platform-based machine.

Methods: Mobisante MobiUS SP1 system with 2 mechanical sector (3.5 and 7.5 MHz) probes was used to acquire images of the tongue and measure the diameter of the hyomental muscle in the mouth floor. In the same group of subjects, imaging and measurements were repeated using BK Medical Flex Focus 400 ultrasound system with linear (18 MHz ) and curved 5 (MHz) transducers. The MobiUS system was also used to image plastic cylinders and procedure needles embedded in tofu bars. Outside diameters of cylinders were measured using digital calipers and sonography.

Results: The mean diameter of the hyomental muscle in 10 healthy volunteers was 7.22 ± 1.6 mm using BK 18 MHz probe, 7.11 ± 1.7 mm using MobiUS 7.5 MHz probe, and 7.84 ± 2 mm using MobiUS 3.5 MHz probe. These means were not statistically different (BK vs Mo 7.5, P = .74, and BK vs Mo 3.5, P = .13). The mean outside diameter of plastic cylinders measured with digital calipers was 10.1 ± 0.2 mm (n = 5) vs 9.8 ± 0.3 mm and 10.2 ± 0.2 mm using 3.5 and 7.5 MHz probes, respectively. These means were not statistically different (calipers vs Mo 3.5, P = .16 and calipers vs Mo 7.5, P = .39).

Conclusion: Mobisante MobiUS system was able to acquire clinically useful images of the suprahyoid airway and muscular architecture in the mouth floor and allowed accurate measurements of linear distances.