We analyzed the lag in the gastric emptying immediately after of cardiac surgery, in fourteen patients by means of administration of amniophem. Plasmatic levels (area under the curve) and time in reaching he highest ones were measured. The main objective was to detect any difference between measurements in our patients and healthy adults (control group). A secondary objective was to find any relationship between our results and other factors, such as pre and post-surgical conditions and demographic features. We found a significant reduction in the area under the area under he curve and in time to obtain the highest plasmatic levels with respect to group. In addition, we observed a significant correlation between our results and other issues: age and fentanyl doses during surgical proceedings.