Table 3.

Differences in the UGAP values between different breathing patterns and positions.

	t/Z value	p value
Fasting (SP, S5, 1) & Fasting (SP, S5, ROI PLC)	− 0.999†	0.323
Fasting (SP, S5, 1) & Fasting(SP, EI)	− 1.872‡	0.061
Fasting (SP, S5, 1) & Fasting(SP, EE)	− 1.361‡	0.174
Fasting (SP, S5, 1) & Fasting (SP, non-S5)	0.271†	0.788
Fasting (SP, S5, 1) & Fasting(LP)	0.073†	0.942
Fasting (SP, S5, 1) & 2 h after a meal (SP, S5)	− 1.036‡	0.300

UGAP values showed good intraobserver and interobserver variability, so we compared the UGAP values in the first time (Fasting [SP, S5, 1]) with the UGAP values in other conditions.

SP supine position, S5 segment V, ROI PLC region of interest (ROI) perpendicular to liver capsule, EI end of inspiration, EE end of expiration, LP lateral position, BMI body mass index, UGAP ultrasound-guided attenuation parameter.

^‡Wilcoxon Mann–Whitney rank-sum test.

^†Paired sample T test.