Effective pain management during percutaneous thermal ablation of liver tumors outside the operating room remains a significant challenge. While hepatic hilar nerve block (HHNB) provides partial analgesia, its incomplete efficacy often requires opioid supplementation, potentially increasing perioperative risks. Esketamine, an N-methyl-D-aspartate receptor antagonist, exhibits unique dual analgesic-sedative properties that may address this therapeutic gap, thus obviating the necessity for opioids. This prospective dose-finding study aimed to establish the median effective dose (ED50) and 95% effective dose (ED95) of esketamine for opioid-free analgesia during ultrasound-guided thermal ablation of liver tumors under HHNB. Afterwards, the investigators will conduct an RCT study to evaluate the safety of the dose of esketamine ED95 through the incidence of respiratory depression.
This research will be divided into two stages. (i) In Phase one, a prospective dose discovery study using the Dixon sequential method will be conducted, aiming to determine the median effective dose (ED50) and 95% effective dose (ED95) of esketamine during ultrasound-guided thermal ablation of liver tumors under hepatic hilar nerve block (HHNB). Esketamine will be initiated by intravenous drip at 0.3 mg∙kg-1, and then based on the patient's response to pain (positive: body movement or complaint of pain; Negative: No body movement or no reported pain. The dose will be adjusted, with a fluctuation step of 0.02 mg∙kg-1 up and down. All patients will receive a standardized anesthesia regimen, including the administration of midazolam at 0.03 mg∙kg-1 and hepatic portal nerve block (10 ml of 0.5% ropivacaine) under ultrasound guidance. Local anaesthesia will be administered using 10 ml of 1% lidocaine, which will be applied until the liver capsule is reached. The test will continue until six cross-pairings will be obtained. Probabilistic regression analysis will be used to calculate the ED50 and ED95 of esketamine with a 95% confidence interval. (ii) The investigators will conduct a single-center, randomized, double-blind controlled trial in Phase Two to evaluate the safety of the esketamine ED95 dose under the monitoring anesthesia care program based on the incidence of respiratory depression. The intervention group will be injected with the dose of esketamine ED95; the control group will be first injected with fentanyl at a dose of 1 μg∙kg-1. Both groups of patients will receive the same anesthesia regimen, namely midazolam 0.03 mg∙kg-1, and hepatic portal nerve block (0.5% ropivacaine 10 ml) will be performed under ultrasound guidance. Intravenous injection of 100 mg of flurbiprofen axetil for auxiliary analgesia. Intravenous injection of 4 mg of ondansetron to prevent nausea and vomiting.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
QUADRUPLE
Enrollment
79
Using Dixon's up-and-down sequential method, esketamine will be titrated intravenously from an initial 0.3 mg∙kg-1 dose with 0.02 mg∙kg-1 adjustments based on intraprocedural responses to pain (Positive: purposeful somatic movement or the complaint of pain; Negative: no movement or no complaint of pain). The titration sequence will continue until six crossover inflection points are observed.
The intervention group will be injected with the dose of esketamine ED95.
The control group will be injected with fentanyl 1 μg∙kg-1.
Department of Anesthesiology, The First Affiliated Hospital of Xiamen University, 55 Zhenhai Road, Xiamen, China
Xiamen, Fujian, China
thermal ablation-induced somatic responses to pain
Positive: Body movement or complaint of pain. Negative: No body movement or no reported pain. This scale will be administered during the surgery at the first stage of the research.
Time frame: Day 1 (During the surgery at the first stage of the research)
Incidence of respiratory depression
By comparing with the control group, evaluate the safety of ED95 of esketamine by the incidence of respiratory depression at T2-T5 of the second stage of the research. The primary outcome is the incidence of respiratory depression, which is defined as SpO2 \<90% or EtCO2 \>55 mmHg. T2: 60 seconds after esketamine injection; T3: 5 minutes after HHNB; T4: During thermal ablation of liver tumors; and T5: In the PACU.
Time frame: Day 1 (T2-T5 of the second stage of the research)
HR
HR: heart rate. T1: Prior to anesthesia (10 minutes after positioning); T2: 60 seconds after esketamine injection; T3: 5 minutes after HHNB; T4: During thermal ablation of liver tumors; and T5: In the PACU.
Time frame: Day 1 (T1-T5 of the first and second stages of the research)
MAP
MAP: Mean Arterial Pressure. T1: Prior to anesthesia (10 minutes after positioning); T2: 60 seconds after esketamine injection; T3: 5 minutes after HHNB; T4: During thermal ablation of liver tumors; and T5: In the PACU.
Time frame: Day 1 (T1-T5 of the first and second stages of the research)
RR
RR: respiratory rate. T1: Prior to anesthesia (10 minutes after positioning); T2: 60 seconds after esketamine injection; T3: 5 minutes after HHNB; T4: During thermal ablation of liver tumors; and T5: In the PACU.
Time frame: Day 1 (T1-T5 of the first and second stages of the research)
SPO2
SPO2: peripheral oxygen saturation. T1: Prior to anesthesia (10 minutes after positioning); T2: 60 seconds after esketamine injection; T3: 5 minutes after HHNB; T4: During thermal ablation of liver tumors; and T5: In the PACU.
Time frame: Day 1 (T1-T5 of the first and second stages of the research)
EtCO2
EtCO2: End-expiratory carbon dioxide. T2: 60 seconds after esketamine injection; T3: 5 minutes after HHNB; T4: During thermal ablation of liver tumors; and T5: In the PACU.
Time frame: Day 1 (T2-T5 of the first and second stages of the research)
Adverse events
Adverse events will encompass a range of systems, including the cardiovascular system (eg. high/low blood pressure and sinus tachycardia/bradycardia), as well as symptoms such as nausea, vomiting, dizziness, and mental symptoms. T2: 60 seconds after esketamine injection; T3: 5 minutes after HHNB; T4: During thermal ablation of liver tumors; T5: In the PACU. T6 to T8: 2, 6, and 24 hours after the procedure.
Time frame: Day 1 (T2-T8 of the first and second stages of the research)
NRS
The Numeric Rating Scale (NRS) will be utilized to assess postoperative pain, with a range of 0 representing no pain and 10 representing severe pain. This scale will be administered at 2, 6, and 24 hours following the procedure. T6 to T8: 2, 6, and 24 hours after the procedure.
Time frame: Day 1 (T6-T8 of the first and second stages of the research)
The need for remedial analgesia
The consumption of remedial analgesia will be the total consumption of acetaminophen documented at 2, 6, and 24 hours after the procedure. T6 to T8: 2, 6, and 24 hours after the procedure.
Time frame: Day 1 (T6-T8 of the first and second stages of the research)
Success rate of anesthesia
Anesthesia success will be defined as inadequate analgesia requiring ≤3 rescue doses of remifentanil within 10 min throughout the procedure. The success rate of anesthesia will be calculated by dividing the number of successful anesthesia cases by the total number of cases. T2: 60 seconds after esketamine injection; T3: 5 minutes after HHNB; T4: During thermal ablation of liver tumors
Time frame: Day 1 (T2-T4 of the second stage of the research)
Induction duration
Induction duration is defined as the period from the start of anaesthetic drug injection to the commencement of the surgical procedure at the second stage of the research.
Time frame: Day 1 of the second stage of the research
Duration of awakening
Duration of awakening is defined as the period from the conclusion of the surgical procedure to the moment of eye-opening.
Time frame: Day 1 of the second stage of the research
Duration of stay in the hospital
Duration of stay in the hospital is measured from the moment the patient enters the operating room until the moment they are discharged.
Time frame: Day 1 and Day 2 of the second stage of the research
The satisfaction of the sonographer
The satisfaction score of the sonographer will be collected postoperatively on Day 1, using a scale ranging from 0 to 10, with 0 representing dissatisfaction and 10 representing very satisfied.
Time frame: Day 1 of the second stage of the research
The satisfaction of patients
The satisfaction of patients will be collected postoperatively on Day 2, using a scale ranging from 0 to 10, with 0 representing dissatisfaction and 10 representing very satisfied.
Time frame: Day 2 of the second stage of the research
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