Overview
Local anesthetics (LA) may be administered by injection (retrobulbar, peribulbar, subconjunctival, lid, or facial block) or by instillation (topical anesthesia), Considerable drawbacks of local anesthesia in these patients include the fact that a few patients can remain comfortable on an operating table for procedures that exceed two or three hours.
Sedation may be helpful with LA to decrease the experience of discomfort, movement and anxiety, which may in turn positively influence hemodynamic parameters, patient satisfaction, and overall improve surgical safety. Sedatives used in eye surgeries include benzodiazepines, opioids, alpha-adrenoceptor agonists, and propofol.
Description
Ophthalmic surgery is a precise surgical procedure that requires absolute immobilization. Many ophthalmic procedures can be performed safely in an outpatient setting, using local anesthesia.
Propofol is currently the most commonly used intravenous anesthetic. It has a rapid onset of action, a short half-life and is associated with rapid recovery of cognitive ability. However, propofol can lead to injection pain, propofol infusion syndrome, and hemodynamic and respiratory depression. Therefore, there is a need for new anesthetic drugs with high efficacy and fewer side effects while providing stable and controllable anesthesia.
Remifentanil is a short-acting esterase metabolized opioid with analgesic and sedative effects. Its half-life is about 5-10 min so that it can be titrated closely in response to changes in intraoperative requirements and with a low risk of accumulation.
Remimazolam is a novel ultrashort-acting benzodiazepine agonist that works on γ-aminobutyric acid type A (GABA-A) receptors to reduce neuronal excitation and thereby achieve hypoactivity and sedation in the body. Remimazolam is metabolized by a nonspecific esterase, and the metabolite has no pharmacological effect, which allows prolonged infusion without accumulation.
It provides rapid anesthesia and arousal while stabilizing hemodynamics and produces less depression of respiration, making it more suitable for use in elderly and hemodynamically unstable patients.
Eligibility
Inclusion Criteria:
- Age > 40 years.
- Both sexes.
- American Society of Anesthesiology (ASA) physical status I-III.
- Undergoing long-eye surgeries under local anesthesia using peribulbar block with an expected surgical time of more than one hour.
Exclusion Criteria:
- Patients on aspirin or anticoagulants.
- Allergy to any study medication.
- Drug abuse.
- Uncontrolled hypertension.
- Hyperthyroidism.
- Frequent cough.
- Impaired hearing.
- Severe liver and kidney dysfunction.
- Neurological or psychological disorders.
- Partial or failed block.