Dexmedetomidine and Pregabalin for Conscious Sedation During Cataract Surgery

Study Overview
=================
Brief Summary
-----------------
Although topical anesthesia by eye drops for cataract surgery is a non-invasive technique but it may provide insufficient anesthesia which requires the intraoperative use of additional topical local anesthetics and raises the need for sedation.

Detailed Description
-----------------
The present study is constructed to evaluate the effect of pregabalin on sedation using dexmedetomidine for cataract surgery under topical anesthesia . In the dexmedetomidine-pregabalin group, the patients will be premedicated by pregabalin. In the placebo group (control group) the patients will be premedicated by placebo capsules. All patients will be sedated by dexmedetomidine. Sedation will be assessed as a primary outcome measurement where pain, vital signs, intraoperative and postoperative pain, total analgesic needs and side effects will be assessed as secondary outcome measurements.

Official Title
-----------------
Dexmedetomidine With or Without Pregabalin Premedication for Conscious Sedation During Cataract Surgery Under Topical Anesthesia. A Randomized Double-blind Placebo-controlled Trial.

Conditions
-----------------
Conscious Sedation

Intervention / Treatment
-----------------
* Drug: Dexmedetomidine Injection
* Drug: Placebo oral capsule
* Drug: Pregabalin Oral Capsule
* Drug: topical anesthesia


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: American Society Of Anesthesiologists (ASA) I and II physical status. Scheduled for cataract extraction under topical anesthesia. Exclusion Criteria: Hepatic or renal impairment. Taking chronic psychotropic medications. Mental instability. Morbid obesity. Alcohol abuse. Substance abuse. Pregnant and lactating females. History of allergy to the study drugs used

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Control<br>placebo oral capsule+ dexmedetomidine+topical anesthesia | Drug: Dexmedetomidine Injection<br>* Dexmedetomidine Injection 1 μg/kg then 0.5-1 μg/kg/h infusion<br>* Other names: Dexmedetomidine;Drug: Placebo oral capsule<br>* placebo oral capsules<br>* Other names: placebo;Drug: topical anesthesia<br>* topical anesthesia of the eye by Benoxinate Hydrochloride 0.4% Eye Drops<br>* Other names: Benoxinate Hydrochloride 0.4% Eye Drops;|
| Active Comparator: Dexmedetomidine- Pregabalin<br>Pregabalin Oral Capsule +Dexmedetomidine Injection+topical anesthesia | Drug: Dexmedetomidine Injection<br>* Dexmedetomidine Injection 1 μg/kg then 0.5-1 μg/kg/h infusion<br>* Other names: Dexmedetomidine;Drug: Pregabalin Oral Capsule<br>* 150 mg pregabalin Oral Capsule<br>* Other names: pregabalin;Drug: topical anesthesia<br>* topical anesthesia of the eye by Benoxinate Hydrochloride 0.4% Eye Drops<br>* Other names: Benoxinate Hydrochloride 0.4% Eye Drops;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| sedation score changes | Ramsay sedation score from 1 to 6. score 2 to 4 is acceptable sedation. Score 5 or 6 is excessive sedation. | baseline,1hour after premedication, intraoperative every 5 minutes ,postoperative every 6hours for 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| pain score changes | verbal pain score (VPS) from 0 = no pain to 10= the worst pain imaginable. scor ≥ 3 indicates need of analgesia | baseline,1hour after premedication, intraoperative every 5 minutes ,postoperative every 6hours for 24 hours | 
| heart rate changes | beats/minute | baseline,1hour after premedication, intraoperative every 5 minutes ,postoperative every 6hours for 24 hours | 
| arterial blood pressure changes | mmHg | baseline,1hour after premedication, intraoperative every 5 minutes ,postoperative every 6hours for 24 hours | 
| arterial oxygen saturation | the percentage of hemoglobin saturation with oxygen in arterial blood. | baseline,1hour after premedication, intraoperative every 5 minutes ,postoperative every 6hours for 24 hours | 
| respiratory rate | breath/minute | baseline,1hour after premedication, intraoperative every 5 minutes ,postoperative every 6hours for 24 hours | 
| total dexmedetomidine consumption | ug | intraoperatively | 
| Incidence of respiratory depression | percentage | from administering premedication till 24 hours postoperative. | 
| Incidence of hypotension | percentage | from administering premedication till 24hours postoperative | 
| Incidence of bradycardia | percentage | from administering premedication till 24hours postoperative | 
| Incidence of ataxia | percentage | from administering premedication till 24hours postoperative |