Itching Caused by Epidural Use of Opioids, Itching Symptoms
Conditions
Keywords
Transcranial direct current stimulation, Opioid-induced Pruritus after Epidural Administration, Cesarean section
Brief summary
Cesarean section is the most common obstetric surgery worldwide. Epidural anesthesia has become the preferred anesthesia method for cesarean sections due to its definite analgesic effect and minimal impact on mother and baby. To ensure postoperative analgesia, intrathecal administration of morphine (the preferred opioid for obstetric intrathecal analgesia) is a routine clinical protocol, but morphine-induced postoperative pruritus is a common adverse reaction. A study targeting the cesarean section population confirmed that the incidence of pruritus after epidural morphine administration is as high as 40%-75%.Transcranial direct current stimulation (tDCS) can enhance the activity of GABAergic inhibitory interneurons in the spinal dorsal horn through the cortical-spinal descending pathway, reverse the inhibitory effect of morphine on them, and restore negative feedback regulation of itch-specific GRPR⁺ neurons; at the same time, it downregulates the phosphorylation level and membrane expression of μ-opioid receptors in the spinal dorsal horn, weakening the receptor activation efficiency of morphine. On the other hand, tDCS can reduce peripheral nerve excitability, decrease mast cell degranulation in the skin, and reduce the release of histamine and tryptase; simultaneously, it inhibits the activation of glial cells in the spinal cord/cortex, decreases the secretion of pro-inflammatory factors such as TNF-α and IL-6, and blocks the vicious cycle of 'inflammation-receptor upregulation-itch exacerbation,' thereby reducing the occurrence of itch.This study aims to explore the effect of transcranial direct current stimulation (tDCS) on the incidence of morphine-induced itching after cesarean section by inhibiting the central itch perception circuits in cesarean section patients and antagonizing the disinhibitory effects mediated by μ-opioid receptors in the spinal dorsal horn.
Interventions
DEVICETranscranial direct current stimulation
Patients in the transcranial direct current stimulation (tDCS) group had the anode of the tDCS device placed on the left dorsolateral prefrontal cortex (F3 area) and the cathode on the right mastoid. The tDCS was administered on the day of surgery (starting within 5 minutes after delivery of the fetus and ending upon transfer to the PACU after surgery). The current intensity was 1.5 mA.
DEVICETranscranial direct current stimulation (placebo stimulation)
Sham stimulation group (control group): The anode of the electrical stimulator is placed on the left dorsolateral prefrontal cortex (F3 region) and the cathode on the right mastoid area. A current of 1.5 mA is applied only during the first 30 seconds after the start of stimulation, after which the current is reduced to 0 mA. All other procedures (electrode placement, stimulation duration, intervention frequency) are the same as those in the experimental group.
Sponsors
Affiliated Hospital of Nantong University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Caregiver, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
No
Inclusion criteria
* Age 18-40 years, gestational age 37-41 weeks, singleton full-term pregnancy; * Planned elective or emergency cesarean section, using epidural anesthesia (0.1\~0.2 mg/kg of morphine administered intrathecally during surgery); * American Society of Anesthesiologists (ASA) classification I-III; * Conscious and able to cooperate to complete scale assessments, serum sample collection, and postoperative follow-up; * Voluntarily participate in the study and sign the informed consent form.
Exclusion criteria
* Presence of contraindications for tDCS (such as skull defects, intracranial metal implants, history of epilepsy, coagulation disorders); * Allergy to opioids or a history of severe OEI; * Presence of skin diseases (such as eczema, urticaria), liver diseases (cholestasis), mental disorders, or cognitive impairments; * Coexisting pregnancy complications (preeclampsia, gestational diabetes, autoimmune diseases); * Use of medications within the past week that may affect itch assessment, such as antihistamines, 5-HT3 receptor antagonists, or anti-inflammatory drugs.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Incidence of itching within 24 hours after surgery (defined as VAS itching score ≥1) | 24 hours after surgery | The VAS scoring standard for the degree of itching is a tool used to assess the severity of itching. VAS stands for Visual Analog Scale. The following are the standards for VAS scoring of itching severity: 0 points: No itching. 1-3 points: Mild itching, does not affect daily life. 4-6 points: Moderate itching, somewhat affects daily life. 7-9 points: Severe itching, seriously affects daily life, requires active treatment. 10 points: Extremely severe itching, unbearable, requires immediate treatment. |
Secondary
| Measure | Time frame |
|---|---|
| Incidence of itching at 12 and 48 hours postoperatively; VAS scores for itching at each time point; duration of itching and time of peak appearance | 12 hours post-operation and 48 hours post-operation |
| Number of times the analgesic pump was pressed and the doses of additional morphine within 48 hours postoperatively; VAS pain scores at 12, 24, and 48 hours postoperatively | 12 hours, 24 hours, and 48 hours after surgery |
| Maternal adverse reactions (nausea and vomiting, drowsiness, dizziness, ear pain, skin erythema) incidence; neonatal 1-minute and 5-minute Apgar scores, birth weight, complications within 72 hours (jaundice, shortness of breath, feeding difficulties) | Within 72 hours after surgery |
| Preoperative and postoperative 24h serum histaminelevels | 24 hours before surgery and 24 hours after surgery |
| Preoperative and postoperative 24h trypsin-like enzymelevels | 24 hours before surgery and 24 hours after surgery |
| Preoperative and postoperative 24h TNF-α levels | 24 hours before surgery and 24 hours after surgery |
| Preoperative and postoperative 24h IL-6 levels | 24 hours before surgery and 24 hours after surgery |
| Preoperative and postoperative 24h β-endorphin levels | 24 hours before surgery and 24 hours after surgery |
| Preoperative and postoperative 24h gastrin-releasing peptide precursor (ProGRP) levels | 24 hours before surgery and 24 hours after surgery |
Countries
China
Contacts
CONTACTChao Chao Zhong, M.D.
Outcome results
None listed