Free-hand Needle guide p-value Needle isibility; % 17.9 (8.2-28.3) 34.2 (15.0-55.1) 0.022 Total procedural time; s 123.8 (96.5-165.9) 107.9 (76.6-120.2) 0.019 Proceduralist satisfaction; 0-10 5.5 (4.0-7.8) 8.0 (5.3-8.8) 0.016

Table 3: Outcome variables comparing free hand vs. needle guidance technique in performing ultrasound-guided TAP blocks. Numbers are median (IQR).