Perbandingan Volume Residual Lambung Berdasarkan Pemeriksaan Ultrasonografi Dua Jam Pasca Pemberian Cairan Maltodextrin 12,5% Pada Populasi Obesitas Dan Non Obesitas = Comparison of Gastric Residual Volume Based on Ultrasonography Examination Two Hours After Administration of 12,5% Maltodetrin Liquid in Obese and Non-Obese Populations