The Effects of Spinal Anesthesia on ED50 and BIS50 of Etomidate for the Loss of Consciousness (LOC)

The purpose of this study is to investigate the effect of spinal anesthesia on ED50 and BIS50 of etomidate for the loss of consciousness (LOC) by using up-and-down method.The hypothesis was that spinal anesthesia could significantly reduce the etomidate bolus dose for the LOC and could also achieve hemodynamic stability during anesthesia induction.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The combination of spinal with general anesthesia has been demonstrated to provide many clinically relevant advantages, however, this technique often experiences hypotension and bradycardia in the induction period of combined anesthesia. Etomidate is a carboxylated imidazole-derived hypnotic, and it is the most cardiovascularly stable intravenous induction drug, with the possible exception of ketamine. Meanwhile, the previous and our studies have been reported that spinal anesthesia has a direct sedative effect on animals and humans, and it markedly reduces the dose of hypnotic agents. To date, there is no dose-ranging study on the effect of spinal anesthesia on dosage of etomidate for the loss of consciousness (LOC). In the present study, investigators aim to investigate the effect of spinal anesthesia on the median effective dose (ED50) and the BIS value (BIS50) of etomidate at which 50% of patients lose consciousness compared to etomidate alone by using up-and-down method.

Patients were randomly allocated to one of two groups: only etomidate in group E (n=27) and spinal anesthesia combined with etomidate in group SE (n=21) using a randomization table. Patients in the SE group received spinal anesthesia first, and bilateral sensory anesthesia level was confirmed to remain at the T4-T6 level. After confirmation of the level of sensory anesthesia, the administration of etomidate was conducted. The etomidate (Nhwa Pharmaceutical, Jiangsu, China) starting dose of E group and SE group is 0.105 mg/kg and 0.089mg/kg, respectively. The dose of etomidate used for next patient was determined according to the response of the previously tested patient using the up-and-down method. If the patient lose consciousness, the dose of etomidate was reduced by one dose gradient for the next patient, and if didn't lose consciousness, the dose of etomidate was increased by one dose gradient (one dose gradient is r=1:0.85, that is, the ratio of high dose/low dose which are adjacent two doses). The testing of different dose levels of etomidate continued on consecutive randomised patients until a sample size of seven crossover points from "conscious" to "LOC" was reached

Study Type

Interventional

Enrollment (Actual)

54

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Ningxia
      • Yinchuan, Ningxia, China, 750004
        • General Hospital of Ningxia Medical University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • ASA physical status I-II
  • Body mass index (BMI) between 18.0 and 24.5 kg/m2
  • Undergoing short elective laparotomy procedures, hysteroscopic and vaginal operation

Exclusion Criteria:

  • Contraindication to spinal anesthesia
  • Hearing loss
  • History of cardiovascular disease, psychiatric and central nervous system diseases
  • Hepatic or renal dysfunction
  • Severe diabetes or hyperkalemia
  • History of drug and alcohol abuse
  • An allergy to amide local anesthetics or etomidate
  • Adrenocortical hypofunction

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: OTHER
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: TRIPLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
EXPERIMENTAL: Group SE
21 patients received spinal anesthesia first. After confirmation of the level (T4-T6) of the sensory anesthesia, the sequential administration of etomidate was conducted
The spinal puncture was performed with a 25 G Sprotte needle at the L3-4 or L2-3 interspinous space. Hyperbaric bupivacaine 0.5% (3 ml) was administered into the spinal space. Hyperbaric bupivacaine is obtained through the addition of glucose 10% (1ml) to bupivacaine 0.75% (2ml). Cerebrospinal fluid aspiration (0.1 ml) was done to confirm correct needle placement before and after spinal drug administration. Whereafter the patient was turned rapidly to the supine position, sensory anesthesia height was evaluated bilaterally using a pinprick test with the sharp tip of a safety pin every 1 min until 15 min after the initiation of the spinal anesthesia, bed tilting (upwards, horizontal, or downwards) was performed until bilateral sensory anesthesia level was confirmed to remain at the T4-T6 level
PLACEBO_COMPARATOR: Group E
27 patients without spinal anesthesia in this group received sequential administration of etomidate
receive etomidate only

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Median effective dose (ED50)of etomidate at which 50% of patients lose consciousness
Time Frame: After etomidate administration to the lowest BIS value appears,usually about 4 minutes
We want to determine Median effective dose (ED50) of etomidate at which 50% of patients lose consciousness in the SE and E group, respectively. It is a value,like 0.105mg/kg. Patients were considered to be loss of consciousness if there Observer's Assessment of Alertness/Sedation (OAA/S) scores were 2,1,or 0.
After etomidate administration to the lowest BIS value appears,usually about 4 minutes
BIS value (BIS50) of etomidate at which 50% of patients lose consciousness
Time Frame: After etomidate administration to the lowest BIS value appears,usually about 4 minutes
We want to determine BIS value (BIS50) of etomidate at which 50% of patients lose consciousness in the SE and E group, respectively. It is a unitless value,like 60. Patients were considered to be loss of consciousness if there Observer's Assessment of Alertness/Sedation (OAA/S) scores were 2,1,or 0.
After etomidate administration to the lowest BIS value appears,usually about 4 minutes

Secondary Outcome Measures

Outcome Measure
Time Frame
The change of Mean Arterial Pressure (MAP)
Time Frame: Baseline, l min (T1), 2min (T2), 3min (T3), 5min (T5) after administration of etomidate
Baseline, l min (T1), 2min (T2), 3min (T3), 5min (T5) after administration of etomidate
The change of heart rate (HR)
Time Frame: Baseline, l min (T1), 2min (T2), 3min (T3), 5min (T5) after administration of etomidate
Baseline, l min (T1), 2min (T2), 3min (T3), 5min (T5) after administration of etomidate

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Principal Investigator: Li Ningkang, General Hospital of Ningxia Medical University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ACTUAL)

June 1, 2017

Primary Completion (ACTUAL)

July 15, 2017

Study Completion (ACTUAL)

July 15, 2017

Study Registration Dates

First Submitted

July 21, 2017

First Submitted That Met QC Criteria

August 3, 2017

First Posted (ACTUAL)

August 4, 2017

Study Record Updates

Last Update Posted (ACTUAL)

September 6, 2017

Last Update Submitted That Met QC Criteria

September 2, 2017

Last Verified

August 1, 2017

More Information

Terms related to this study

Other Study ID Numbers

  • mz2017

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

safety

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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