Pregabalin Effects on Hypotensive Anesthesia During Spine Surgery.

Study Overview
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Brief Summary
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Elective lumbar spine surgical procedures are commonly performed under controlled hypotension during general anesthesia. That is beneficial to limit the intraoperative blood loss and transfusions and improves surgical field. Deliberate hypotension could be achieved via various medications but mostly associated with significant side effects. Pregabalin effectively augmented hypotensive anesthesia. The hypothesis is that Pregabalin 150 mg single preoperative dose may augment intraoperative deliberate hypotension that will be reflected on blood loss and nitroglycerin consumption.

Detailed Description
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An arterial line will be established then general anesthesia will be conducted. After adequate preoxygenation, anesthesia induction by IV fentanyl 1.5µg/kg, propofol 2 mg/kg, and atracurium 0.5 mg/kg then appropriated size tracheal tube. The ventilator settings will be adjusted to maintain the end-tidal carbon dioxide tension (ETco2) at 30-35 mm Hg. Anesthesia will be maintained by isoflurane concentration 1.2%, with 40% oxygen in air then IV infusion of fentanyl 0.05 mcg/kg/min was started while atracurium 0.1 mg/kg incremental dose as required. Then patients will be turned into the prone position above pad support permitting free hanging of the abdomen. Intraoperatively, the target mean arterial arterial blood pressure (MBP) is 55-65 mm Hg. After surgical incision, if MBP exceeds 65 mm Hg (defined as hypertension) it will be managed by: increasing isoflurane MAC up to 2%, if no response after 5 min, Nitroglycerin infusion initiated at 0.5 mcg/kg/min to 40 mcg/kg/min. Hypotension (MBP <55 mm Hg) will be treated by stopping nitroglycerin, proper compensation of losses, reducing Isoflurane MAC. If persisted; vasoactive drugs will be used. Bradycardia (HR <50 beat/min.), treated with 0.01 mg/kg atropine IV increments. The nitroglycerin infusion will be stopped after the finial surgical hemostasis. Fentanyl infusion will be stopped before ligament sutures. Isoflurane will be closed after the last surgical suture. After dressing, patient will be turned to the supine position and morphine 0.025 mg/kg IV will be administered then 0.04 mg/kg neostigmine and 0.015 mg/kg atropine for reversal. Extubation will be done after establishment of acceptable spontaneous respiration.

Official Title
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Pregabalin Effects on Hypotensive Anesthesia During Spine Surgery.

Conditions
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Spine Surgery

Intervention / Treatment
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* Drug: Pregabalin
* Drug: placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists (ASA) score I-II admitted to undergo lumbar discectomy or spinal fixation surgery under general anesthesia Exclusion Criteria: Patients on anti-hypertensive treatment, diuretics, corticosteroids, pregabalin, gabapentin, anticonvulsants, antipsychotics, alcohol addiction or drug abuse patients with history of allergy to any drug used in the study . pregnant or nursing women patients with peripheral neuropathy, endocrinal diseases, bleeding abnormality, cardiac, hepatic or renal impairment

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Pregabalin group<br>(n=53): | Drug: Pregabalin<br>* Pregabalin 150 mg capsule, one h preinduction of general anesthesia<br>* Other names: (LYRICA® 150 mg capsule- PFIZER);|
| Placebo Comparator: placebo group<br>(n=53): | Drug: placebo<br>* given a placebo identical capsule once one hour before anesthesia<br>* Other names: control;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Nitroglycerin consumption | the total nitroglycerin consumption in milligram to maintain the target mean arterial pressure (MAP) 55- 65 mmHg. | Intraoperative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Estimated blood loss | towels are weighted, plus suction volume without irrigation fluids in milliter. | intraoperative | 
| The number of transfused blood unites | Packed red blood cell unites | intraoperative | 
| heart rate (HR) | in beat/min | Basal, during intubation, then at 1, 5, 30, 60, 90, 120, 150, 180, 210 minutes post extubation, then postoperatively at 1 and 2 hours. | 
| end-tidal isoflurane concentration | in percent | at 30, 60, 90, 120, 150 , 180, 210 minutes after intubation. | 
| Surgeon satisfaction about the field | using a six-point scale (0 = no bleeding, virtually bloodless field; 5 = uncontrolled) bleeding). | within 2 hours from the end of surgery. | 
| Sedation | (Ramsay sedation scale) | at 0, 2, 4, 6, 12, 24 hours postoperatively | 
| The time to the first request of analgesia. | in hours | 24 hours postoperative | 
| Postoperative pain | (VAS 0-10 scale) 10 is the worst pain | at 0, 2, 4, 6, 12, 24 hours postoperatively. | 
| The total morphine consumption | in mg | in the 1st 24 hours postoperatively | 
| Frequency of adverse effects | dizziness, headache, nausea and vomiting, or pruritus. | during the first 24 hours postoperatively | 
| Peak airway pressures | in centimeter water | 10 minutes after settled prone position | 
| invasive mean arterial blood pressure (MAP) | in millimeter mercury (mmHg) | Basal, during intubation, then at 1, 5, 30, 60, 90, 120, 150, 180, 210 minutes post extubation, then postoperatively at 1 and 2 hours. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Pregabalin, hypotensive anesthesia, blood loss, analgesia