Anesthesia
Conditions
Keywords
propofol, midazolam, remifentanil, combination, synergic, pharmacodynamics, Loss of consciousness
Brief summary
Propofol is a well-known induction agent which can provide sound and quick hypnosis with anti-emetic effects. However, dose dependent hypotension or bradycardia have reported while using this agent. Propofol in combination with remifentanil or midazolam can result in synergistic or additive effect in elderly patients. There are not many studies which provide minimum dose of propofol to induce hypnosis in combination with these agents and advantage of the combination. The elderly patients (over 65 years old) who are scheduled to undergo general anesthesia are enrolled in this study. 120 patients will be randomly allocated to 3 groups(P, PR, PMR). Sample size have been decided due to the previous studies which have mentioned 40 participants as a adequate sample size for this biased coin design - up and down study. After receiving informed consent, patients will be participated in this study. No premedication will be given to the patients before induction. The patients in group P will receive general anesthesia only with propofol and group PR and PMR will receive 0.125 mcg/kg/min remifentanil infusion for 5 min prior to propofol administration. The patients in group PMR will receive 0.015 mg/kg bolus dose of midazolam 1 min after the start of the remifentanil infusion. Initial propofol dose will be 0.5 mg/kg in each group and the dose will be changed by the result of prior study participant. 'Success' of this study will be defined as loss of both verbal response and eyelash reflex in 3 min after propofol administration. When 'success', the next patient will receive the same dose(in 18/19 probability) or 0.125 mg/kg lower dose(in 1/19 probability) of propofol. When 'failure', the next patient will receive 0.125 mg/kg higher dose of propofol at induction period.
Detailed description
Propofol is a well-known induction agent which can provide sound and quick hypnosis with anti-emetic effects. However, dose dependent hypotension or bradycardia have reported while using this agent. Propofol in combination with remifentanil or midazolam can result in synergistic or additive effect in elderly patients. There are not many studies which provide minimum dose of propofol to induce hypnosis in combination with these agents and advantage of the combination. The elderly patients (over 65 years old) who are scheduled to undergo general anesthesia are enrolled in this study. 120 patients will be randomly allocated to 3 groups(P, PR, PMR). Sample size have been decided due to the previous studies which have mentioned 40 participants as a adequate sample size for this biased coin design - up and down study. After receiving informed consent, patients will be participated in this study. No premedication will be given to the patients before induction. The patients in group P will receive general anesthesia only with propofol and group PR and PMR will receive 0.125 mcg/kg/min remifentanil infusion for 5 min prior to propofol administration. The patients in group PMR will receive 0.015 mg/kg bolus dose of midazolam 1 min after the start of the remifentanil infusion. Initial propofol dose will be 0.5 mg/kg in each group and the dose will be changed by the result of prior study participant. 'Success' of this study will be defined as loss of both verbal response and eyelash reflex in 3 min after propofol administration. When 'success', the next patient will receive the same dose(in 18/19 probability) or 0.125 mg/kg lower dose(in 1/19 probability) of propofol. When 'failure', the next patient will receive 0.125 mg/kg higher dose of propofol at induction period.
Interventions
DRUGPropofol
Propofol bolus dose administration according to the predetermined dose by biased coined design up-and-down study.
DRUGRemifentanil
Remifentanil 0.125 mcg/kg/min infusion for 5 min before propofol administration.
DRUGMidazolam
Remifentanil 0.125 mcg/kg/min infusion for 5 min before propofol administration followed by midazolam 0.015 mg/kg administration 1 min after remifentanil infusion start.
Sponsors
Gangnam Severance Hospital
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Masking
DOUBLE (Subject, Caregiver)
Eligibility
Sex/Gender
ALL
Age
65 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* The elderly patients (over 65 years old) who are scheduled to undergo general anesthesia.
Exclusion criteria
* ASA class (American Society of Anesthesiologist physical status classification) IV or higher * Patients with history of allergy or side effects on propofol, remifentanil, midazolam * BMI (body mass index) less than 20 or higher than 30 * Patients taking sedatives or hypnotic agents.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Loss of verbal response and eyelash reflex | 3 minutes after propofol administration | Checking verbal response by verbal stimulation (response or no response). |
| Loss of eyelash reflex | 3 minutes after propofol administration | Checking reflex by palpation of the levator palpebrae (reflex or no reflex). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Mean blood pressure | baseline, propofol administration time (Just after finishing monitoring on the patient in P group, 5 minutes after remifentanil infusion start in PR and PMR group), 1 minute, 2 minutes and 3 minutes after propofol administration | To compare differences among groups in mean blood pressure change (mmHg) |
| Heart rate | baseline, propofol administration time (Just after finishing monitoring on the patient in P group, 5 minutes after remifentanil infusion start in PR and PMR group), 1 minute, 2 minutes and 3 minutes after propofol administration | To compare differences among groups in heart rate change (mmHg) |
Countries
South Korea
Contacts
Primary ContactJiwon An, MD
Outcome results
None listed