A Reliable M-Mode Ultrasound Protocol for the Assessment of Diaphragm Motion

Abstract

SESSION TITLE: Physiology/PFTs/Rehabilitation PostersSESSION TYPE: Poster PresentationsPRESENTED ON: Saturday, March 22, 2014 at 01:15 PM - 02:15 PMPURPOSE: The purpose of this study was to establish a reliable method for the assessment of the diaphragmatic motion via the M-mode ultrasound.METHODS: One expert operator evaluated 51 healthy subjects in two separate occasions: before and after a diaphragmatic breathing technique implementation. The right diaphragmatic motion was measured by M-mode ultrasound imaging in three different transducer positions: longitudinal; transverse with image line in the VII hepatic segment and transverse with image line in the VIII hepatic segment. Two-way ANOVA statistics (p<0.05) were used to assess the influence of the ventilatory education and the transducer positioning in the measurement of the diaphragm range of motion. The reliability of the US measurements, according to the positioning of the transducers, was evaluated by the Pearson correlation coefficient (R) and t-test (p<0.05).RESULTS: ANOVA results indicate that both the ventilatory education and the positioning of the transducer affect the measurement of the diaphragm (p<0.05), but there is no evidence of a synergistic effect of the two (p>0.05). The measurements obtained in the transverse axis with the image line crossing the VIII hepatic segment were the most consistent ones, revealing a strong correlation (R=0.52, p<0.05) with statistical differences between measurements (p<0.05). With this protocol, diaphragmatic range of motion increased 8.4 mm after ventilatory education with a shift in the line slope from 0.05 to 0.39 (after education).CONCLUSIONS: The assessment of the diaphragm range of motion via M mode ultrasound is substantially dependent on the positioning of the transducer. To guaranty objective and reliable quantitative measurements of the diaphragm, the acquisition protocol should be performed in transverse section with the image line centered with the right portal vein, at the VIII hepatic segment.CLINICAL IMPLICATIONS: The transverse positioning of the transducer with the image line crossing the right portal vein at the VIII hepatic segment has the potential to detect diaphragm motion changes, in a reliable and consistent way, and can be used in clinical setting.DISCLOSURE: The following authors have nothing to disclose: Filipe Parreira, Rui Machado, Teresa Tomás, Ricardo RibeiroNo Product/Research Disclosure Information.