This study was approved by the institutional review board of Shengjing Hospital of China Medical University (2018PS027J), and informed consent was obtained from each patient or the next of kin. All experiments were carried out in accordance with the Declaration of Helsinki.
Patients with severe acute pancreatitis admitted to Shengjing Hospital of China Medical University from 1 January 2018 to 31 July 2019 who needed Freka-Trelumina tube placement for enteral nutrition and gastrointestinal decompression were included in the current study. In addition, to compare the novel ultrasound-guided tube placement with previously endoscope-guided (from 1 January 2015 to 31 December 2017) tube palcement, we also analysed the data from the electronic medical record system.
Material and equipment
The following materials and equipment were used in the current study: Freka-Trelumina feeding tube (Fresenius Kabi AG, Bad Homburg, Germany); vacuum suction chamber (length, 95 cm [end to the stomach]; inner diameter, CH16; outer diameter, 5.3 mm); pressure regulating chamber (length, 95 cm [end to the stomach]); feeding chamber (length, 46 cm [end to the jejunum]; inner diameter, CH9; outer diameter, 2.9 mm; total length, 150 cm); ultrasound machine (Philips CX50; Amsterdam, Holand); high frequency probe (L12–3 linear probe); abdominal probe (C5–1 convex probe); 1 dressing bowl; 1 package of gauze; 100 ml of warm water; 1 pair of sterile gloves; 1 piece of 50-ml syringe; 1 piece of sterile towel; and 1 piece of wide tape.
Ultrasound-guided Freka-Trelumina enteral nutrition tube placement
A sterile towel is spread on the operating room table, and warm water is poured into the dressing bowl. After donning sterile gloves, paraffin was used to lubricate the surface of the Freka-Trelumina feeding tube. A guide wire was inserted into the Freka-Trelumina feeding tube, which not only maintained the tension of the feeding tube, but also facilitated the spiral advancement of the tube. Furthermore, the guide wire was more clearly displayed under ultrasound (the guide wire appears as a linear hyperecho). Placement of the Freka-Trelumina feeding tube was divided into two major steps. The first step was to place the Freka-Trelumina tube into the stomach, which was similar to that of the gastric tube placement. The second step was to introduce the Freka-Trelumina tube along the stomach greater curvature into the duodenum through the pylorus under ultrasound guidance, mainly by rotation and propulsion. The operating points for the first step of placing the Freka-Trelumina feeding tube into the stomach were as follows: clean the patient’s nostrils, and select the nasal passage with good ventilation; place gauze on the left hand to hold the tube and hold the tip of the tube with tweezers in the right hand; insert the tube along the naris and advance the tube slowly until the tube is in the throat (a depth of 14–16 cm); continually promote the tube placement to a depth of 55 cm; and if the patient was conscious, ask the patient to swallow repeatedly. Whether or not the Freka-Trelumina tube is curled in the mouth should be determined, then whether or not the tube is in the stomach should be checked ultrasonically. Ultrasound should show that the Freka-Trelumina tube as a linear hyperecho in the stomach. The operating points for the second step of advancing the Freka-Trelumina tube into the duodenum through the pylorus include the following: the sonographer places the abdominal probe near the neck of the gallbladder to observe the antral pylorus; the assistant continues to advance the Freka-Trelumina feeding tube; when the catheter depth reaches 75 cm, ultrasound should demonstrate that the Freka-Trelumina tube with the guide wire (presenting as a linear hyperecho) entered the duodenum through the antral pylorus (Fig. 1); if the quality of the ultrasound image is poor, 100 ml of saline should be injected into the gastric lumen of the Freka-Trelumina tube to improve the image quality (Fig. 2); if the ultrasound did not show the Freka-Trelumina tube passing through the pylorus when the depth of the catheter is 75 cm, it may be curved in the stomach, and the ultrasound could show the Freka-Trelumina tube curving in the stomach (Fig. 3); at this point, the Freka-Trelumina tube should be withdrawn to a depth of 55 cm, then rotated and propulsed again; and after the Freka-Trelumina tube passed through the pylorus smoothly, the assistant continued to advance the catheter until the catheter depth reached 115 cm, then the guide wire was slowly withdrawn. Ultrasound examination showed a “parallel tubular echo” image after the guide wire was withdrawn (Fig. 4). Finally, the Freka-Trelumina feeding tube was fixed to the cheek of the patient with a tape. Bedside abdominal X-ray was used as the gold standard to determine successful placement of the Freka-Trelumina tube in the upper part of the jejunum.
The relevant evaluation indicators of tube placement include the success rate of tube placement, number of tube advances before passing through the pylorus, tube placement time, tube shift rate, and blocking rate. Tube placement is considered successful if ultrasound shows that the tube successfully passes through the pylorus or the end of the tube is located in the jejunum. If the tube placement time exceeds 60 min and the tube is not confirmed to have passed through the pylorus, the tube placement is considered a failure. If the tube is curved in the stomach when the tube is advanced, the tube should be slightly retracted and then re-advanced to pass the pylorus, and the number of advances is recorded once per adjustment. The time when the Freka-Trelumina tube enters the nasal cavity is the initiation time of tube placement, and the completion time is when ultrasound observation confirms that the tube has passed through the pylorus. After the tube has been successfully placed, the depth of the tube is checked every 6 hours after marking the depth of the tube end at the patient’s nose. If the tube shift upside is <10 cm, the tube is adjusted manually and an imaging examination (ultrasound or abdominal X-ray) is used to confirm that the tube has been readjusted to an adequate position (no shift). The tube is considered to be seriously shifted with a shift distance >10 cm, and needs to be re-inserted and counted into the shift rate. If there is obvious obstruction at the stomach or jejunum end which cannot be dredged after introduction of gas or liquid and/or guide wire dredging, the tube is considered blocked.
Patient tolerance at the time of tube placement and after tube placement is as follows: grade I, no special discomfort; grade II, mild discomfort, but tolerable; grade III, severe discomfort, barely tolerable; and grade IV, severe discomfort, intolerable. The white blood cell count, serum amylase, and C-reactive protein were routinely monitored. The clinical syptoms of patients are observed during the treatment; and the complications of eternal nutrition tube were also observed (hemorrhage, arrhythmia, aspiration, and regurgitation).