Study design and patients
The design of this study is shown in Fig. 1. From January 2018 to September 2018, 268 patients with percutaneous biliary tubes who needed cholangiography were selected from the First Affiliated Hospital of Xi'an Jiaotong University to undergo cholangiography using our remote-controlled cholangiography injection device. From July 2017 to December 2017, 279 patients with percutaneous biliary tubes undergoing traditional cholangiography were chosen from the First Affiliated Hospital of Xi'an Jiaotong University as the control group.
Inclusion criteria:
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1.
External biliary drainage requiring cholangiography
Exclusion criteria:
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1.
Biliary tract infection
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2.
Treatment with antibiotics within three days of cholangiography
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3.
Allergy to contrast media
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4.
Renal dysfunction: creatinine clearance rate (CCR) < 60 ml/min
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5.
Heart or lung diseases
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6.
Excessive anxiety and uncooperativeness
All protocols were approved by the Ethics Committee of the First Affiliated Hospital of Xi'an Jiaotong University (NO. XJTU1AF2015LSL-046). All procedures performed in this study involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments. The study was registered on ClinicalTrials.gov (NCT02801500, 16/6/2016). Informed consent was obtained from all participants prior to cholangiography.
Equipment
The remote-controlled injection device consists of a control terminal and an operation terminal, which communicate with each other wirelessly via Bluetooth. The structure and program were designed based on clinical operation requirements.
The control terminal consists of a wireless remote-control panel (Fig. 2c). Using this panel, operators can set up parameters (including injection speed, injection dose, and pressure threshold) and command the operation terminal. In addition, real-time parameters can be collected during cholangiography and exhibited to the operators, such as injection speed, pressure, and dose.
The operation terminal consists of an injection pump, a pressure sensor, and a direct-control panel (Fig. 2a, b). Using the remote-control or direct-control panel, the injection pump can replace a human operator for injecting the contrast dye. The pressure sensor is responsible for detecting the real-time injection pressure. Apart from the method of communication and the display of injection parameters, the functions of the direct-control panel are similar to those of the remote-control panel.
This device requires an extension tube to complete cholangiography. The extension tube has three ports: a syringe port, a pressure port, and a T-adapter port (Fig. 2d). The syringe port, pressure port, and one outlet of the T-adapter port are used to connect a 50-ml syringe, a pressure sensor, and an external biliary drainage tube separately. Another outlet of the T-adapter port can be used to connect a 20-ml syringe for degassing the biliary drainage tube.
Procedure for the experimental group (remote-controlled cholangiography injection device group)
Device preparation
The procedure involved connecting a 50-ml syringe filled with 40 ml of diluted contrast agent (1:1, using normal saline) to the syringe port with an extension tube and prefilling the extension tube with the contrast agent. The 50-ml syringe was then loaded onto the injection pump, and the pressure port of the extension tube was connected to the pressure sensor (Fig. 3a).
Patient preparation
Before cholangiography, patients were required to fill out a form to facilitate post-cholangiography follow-up. The patient then entered the X-ray room and stood in front of the X-ray machine. After the machine was positioned over the right upper abdomen by X-ray, the patient was adjusted to be supine with the head high (20°). The T-adapter of the extension tube was then connected to the external biliary drainage tube (T-tube, percutaneous transhepatic biliary drainage [PTBD], etc.), and a 20-ml syringe was used to extract the remaining air bubbles in the drainage tube and biliary tract from the T-adapter via the extension tube.
Cholangiography procedure using the remote-controlled cholangiography device
The device was adjusted to the correct settings and connected to the power supply. The operator then left the X-ray room and entered the observation room, opened the remote-control panel, and connected the parts of the device via Bluetooth. The injection speed, dose, and pressure threshold were set before initiation of cholangiography and could be adjusted according to the clarity of the image (Fig. 3b).
During cholangiography, the real-time injection speed, dose, and pressure were displayed on the remote-control panel, and the operator could stop or start the injection at any moment. If the feedback pressure surpassed the threshold, the equipment would activate an alarm and stop the injection automatically. After the cholangiography procedure, the operator connected the drainage tube and drainage bag for the patient.
Measurement of occupational exposure
During cholangiography, radiation was monitored by three identical radiation monitors. One was completely exposed to the radiation in the X-ray room, one was protected by a lead suit in the X-ray room, and the third was exposed to natural background radiation in the observation room.
Patient follow-up
One day after cholangiography, the patients were followed up by telephone to assess whether they had symptoms of bile duct inflammation, including fever, jaundice, and abdominal pain.
Data collection for the control group (traditional cholangiography group)
We collected information (including demographic data, type of disease, and type of surgery) from patients undergoing traditional cholangiography from July to December 2017 at the First Affiliated Hospital of Xi'an Jiaotong University. We followed up these patients via telephone to assess whether there were post-cholangiography complications.
Statistical analysis
SPSS Statistics Software 23.0 (IBM Corporation, Armonk, NY, USA) was used for all analyses. Categorical variables are reported as numbers and proportions and were compared using chi-square or nonparametric tests as appropriate. Continuous variables are reported as the means ± SD or medians (interquartile range (IQR)) and compared using the t test, ANOVA, or nonparametric tests. All hypothesis tests were two-sided, and P values < 0.05 were considered statistically significant.