Ultrasound Vs. Free Drainage for Gastric Volume in ICU Patients on Enteral Nutrition

Adult patients hospitalized in intensive care unit due to cerebrovascular disease and receiving mechanical ventilator treatment were included in the study. Patients who were started on semi-solid nutritional solution (standard nutritional products of 1kcal/1 ml according to the comorbidities of the patients) via nasogastric (NG) 14 F polyurethane (PU) feeding catheter (BAXEN Medical, Spain) and reached the full calorie goal for at least 24 hours were included. Full dose calorie calculation of the patients was performed using the Harris-Benedict method (for women: 655.1+(9.56xweight (kg)) -(1.85xheight (cm)) -(4.68xage) for men: 66.5+(13.75xweight (kg)) +(5.03xheight (cm)) -(6.75xage). Feeding tube placement was confirmed with an AP radiograph taken before inclusion in the study.

Patients with shock due to any cause, abdominal surgery, GI bleeding, obstruction, suspected perforation, malabsorption syndrome, prokinetic use or diarrhea, patients with a BMI >35 according to last known height and weight, and pregnant patients (due to inability to achieve right lateral position) were excluded. In addition, patients who could not be imaged, whose feeding protocol was changed and whose vasopressor doses were increased were excluded from the study.

The amount of EN products administered to the patients, age, gender, body weight, height, body mass index (BMI), comorbidities, vasopressor therapy and dose administered during imaging were recorded.

ICU units have a physician-driven nutrition strategy, aiming for an adequate caloric and protein intake. Patients were divided into 3 groups according to implemented nutrition protocols. Ultrasonographic measurements were performed in 24-hour periods after the volume required for the target calorie intake.

Group 1: Patients who received 18 hours of infusion feeding, 6 hours of waiting and one hour of drainage Group 2: Patients who received 5 hours of infusion feeding, 1 hour of waiting and one hour of drainage Group 3: Patients who were fed with continuous infusion for 24 hours and drained for one hour Measurement of gastric volume

1. Measurement by GUSG Using the GE LOQIC P6 (GE healthcare, USA) ultrasound device available in clinic and a convex probe (2-5 MHz), the patient was placed in the right lateral position. To visualize the antrum, the probe was scanned in the sagittal plane in the epigastrium, sliding from left to right along the subcostal margins. The gastric antrum, aorta, superior mesenteric artery and inferior vena cava were visualized just below the left lobe of the liver with the pancreas posterior to it. For the calculation of cross-sectional antral area (CSA), the anterior-posterior diameter and cephalo-caudal diameter (measured 3 times and averaged) were measured from serosa to serosa by capturing the best image during peristaltic movements at the level of the aorta or inferior vena cava. The antral area was calculated according to the formula CSA=(AP×CC×π)/4 (π=3.14) developed by Bolondi et al.

   Two different formulas were then used to calculate GV by CSA. The first formula was proposed by Perlas et al.: Gastric volume (ml)=27+(14.6×right-lateral CSA)-1.28×age1. The second formula was developed by Tacken et al.: Gastric volume (ml)= 79.38+13.32 x right-lat CSA.

2. Measurement by drainage After gastric volume was evaluated by USG, the patient was placed in supine position, NG was connected to a drainage bag and gravity/free drainage was performed in all groups for one hour and the GRV values were recorded.