Study on the Effective Dose and Safety of Esketamine in Hysteroscopic Surgery Under Monitored Anesthesia Care

Xiamen University

Status and phase: Active, not recruiting; Phase 2; Phase 1

Conditions: Intrauterine Synechiae; Intrauterine Polyp

Treatments: Drug: Intravenous the dose of esketamine ED95; Drug: Intravenous remifentanil 1μg∙kg-1; Drug: Determine the ED50 and ED95 of esketamine

Study type: Interventional

Funder types: Other

Identifiers

NCT07034963

XMFHIIT-2025SL092

Details and patient eligibility

About

Cervical dilation-induced somatic responses remain a critical challenge in ambulatory hysteroscopic surgery. Esketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, exhibits unique analgesic and sedative properties that may enhance perioperative somatic response inhibition. However, the effective dose of esketamine under dexmedetomidine-remifentanil based monitored anesthesia care (MAC) during ambulatory hysteroscopic surgery remains to be determined. This prospective dose-finding study aimed to establish the median effective dose (ED50) and 95% effective dose (ED95) of esketamine for cervical response suppression. Afterwards, the investigators will conduct an RCT study to evaluate the safety of the dose of esketamine ED95 through the incidence of respiratory depression.

Full description

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 in inhibiting cervical response. Esketamine will be initiated by intravenous infusion at 0.3 mg∙kg-1, followed by somatic response based on cervical dilation (positive: any exercise; negative: no movement). Dose adjustment will be carried out, with a dose fluctuation step of 0.02 mg∙kg-1 up and down. All patients will receive a standardized anesthesia regimen, including continuous infusion of remifentanil at a dose of 5 μg∙kg∙h-1, combined with dexmedetomidine (infusion at a loading dose of 0.6 μg∙kg-1 for 10 minutes, followed by maintenance infusion at 0.4 μg∙kg-1∙h-1). The test will continue until six cross-pairings are 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 injected with remifentanil 1μg∙kg-1. Both groups of patients will receive the same sedation regimen, namely remifentanil will be continuously pumped at a rate of 5μg∙kg∙h-1 combined with dexmedetomidine (pumped at a loading dose of 0.6 μg∙kg-1 for 10 minutes, followed by maintenance pumping at 0.4 μg∙kg-1∙h-1). Intravenous injection of 100 mg of flurbiprofen axetil for auxiliary analgesia. Intravenous injection of 4 mg of ondansetron to prevent nausea and vomiting.

Enrollment: 95 estimated patients

Sex: Female

Ages: 18 to 55 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Aged 18 - 55 years;
• ASA physical status Ⅰ or Ⅱ;
• Body mass index (BMI) 18 - 28 kg∙m-2;
• Scheduled for elective diagnostic/therapeutic hysteroscopy.

Exclusion criteria

(i) Pharmacological contraindications:

• Known hypersensitivity to study medications (esketamine, remifentanil, dexmedetomidine);
• Opioid or benzodiazepine medications dependence;
• Analgesic/psychotropic medication use within 48 hours preoperatively;
• Participation in any other drug clinical trial within the preceding three months.

(ii) Comorbidities:

• Significant cardiopulmonary dysfunction (NYHA III-IV, FEV₁/FVC <70%);
• Hepatic impairment (Child-Pugh B/C);
• Uncontrolled hypertension, intracranial hypertension, intraocular hypertension or hyperthyroidism;
• Neurological/psychiatric conditions (epilepsy, schizophrenia, depression);
• Active gastroesophageal reflux disease (GERD-Q score ≥8). (iii) Airway/Perioperative Risks:
• Anticipated difficult airway (Mallampati III-IV, thyromental distance <6 cm) or airway stenosis;
• Non-fasted status (solids <8h, clear fluids <2h preoperatively).

Trial design

Primary purpose: Supportive Care

Allocation: Randomized

Interventional model: Sequential Assignment

Masking: Quadruple Blind

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95 participants in 2 patient groups

Determine the ED50 and ED95 of esketamine by Dixon's up-and-down method

Experimental group

Description:

According to Dixon's up-and-down sequential design, esketamine will be initiated at 0.3 mg∙kg-1 intravenously, followed by dose adjustments (0.02 mg∙kg-1 increments/decrements) based on somatic responses to cervical dilation (positive: any movement; negative: no movement). The tests will continue until six crossover pairs are achieved.

Treatment:

Drug: Determine the ED50 and ED95 of esketamine

Evaluate the safety of the dose of esketamine ED95 by the incidence of respiratory depression

Active Comparator group

Description:

The intervention group will be injected with the dose of esketamine ED95; the control group will be injected with remifentanil 1μg∙kg-1. Both groups of patients will receive the same Monitoring Anesthesia Care (MAC) regimen, namely, remifentanil will be continuously pumped at a rate of 5μg∙kg∙h-1 combined with dexmedetomidine (a loading dose of 0.6 μg∙kg-1 for 10 minutes, followed by maintenance dose of 0.4 μg∙kg-1∙h-1). Intravenous injection of 100 mg of flurbiprofen axetil for auxiliary analgesia. Intravenous injection of 4 mg of ondansetron to prevent nausea and vomiting. The study at this stage will evaluate the safety of the dose of esketamine ED95 through the incidence of respiratory depression.

Treatment:

Drug: Intravenous remifentanil 1μg∙kg-1

Drug: Intravenous the dose of esketamine ED95