الفهرس 
Controlled hypotensive anesthesia
Indications of propranolol:Only 14 pages are availabe for public view
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Abstract
Functional Endoscopic Sinus Surgery (FESS) is the cornerstone therapeutic management for refractory chronic sinusitis. Though relatively safe, there is possibility for both minor and major complications, including cerebrospinal fluid leak, orbital or intracranial injury, meningitis, synechiae formation, and bleeding.
Intraoperative bleeding causing poor operative field visibility is considered a major concern during FESS.
Hypotensive anesthesia is one modality for controlling and reduction of bleeding during FESS. Induced hypotension can be done by carefully and deliberately reducing MAP by 30% below its normal value or reversible reduction of MAP to 60 mm Hg and keeping it at that level during the procedure. This can be produced by hypotensive agents like vasodilators, beta- blockers, calcium channel blockers, or by anesthetic medications such as propofol, inhalational drugs and opioids.
Nitroglycerin, a directly acting arterial and venous vasodilator, has been used to produce deliberate hypotension as it has short onset and offset, cheap, easy to use with easy titrability. However, its use is associated with both tachycardia and venous congestion in the surgical site. This causes more bleeding with resultant decrease in the operative field visibility and increase in the time of surgery and anesthesia.
Reflex tachycardia that is occurring during nitroglycerin- induced hypotensive anesthesia in FESS increases both the risk of intra-operative bleeding and the duration of surgery. Our study aimed to compare the effect of oral ivabradine versus oral propranolol as a premedication before nitroglycerin-induced hypotensive anesthesia on the reduction of reflex tachycardia in FESS.
Propranolol is a non-selective beta-blocker that causes a reduction in heart rate, cardiac output, and cardiac contractility. It is absorbed entirely and rapidly from the gastrointestinal tract when taken orally. It reaches its maximal plasma level within 1-1.5 hours of dosing, and its elimination half-life is 2 to 3 hours.
Ivabradine is a heart rate lowering agent that acts by selectively and specifically inhibiting the cardiac pacemaker current (If), a mixed sodium-potassium inward current that controls the spontaneous diastolic depolarization in the sinoatrial (SA) node and hence regulates the heart rate. Inhibition of this channel disrupts If ion current flow, thereby prolonging diastolic depolarization, slowing firing in the SA node, and ultimately reducing the heart rate.
In the current study, forty patients were randomly allocated into two equal groups (twenty each); group P received oral propranolol (10 mg tablet) and group I received oral ivabradine (5 mg tablet) in the evening before the surgery and 1 hour before the induction of anesthesia.
Hemodynamic variables (HR and MAP) were recorded perioperatively. Intraoperative NTG dose used during deliberate hypotension, amount of blood loss, duration of surgery and occurrence of significant persistent hypotension or significant bradycardia were recorded intraoperatively.
It is concluded that premedication with 10 mg of oral propranolol or 5 mg of oral ivabradine in the evening before surgery and 1 hour before anesthesia induction proved to be both safe and effective in reducing reflex tachycardia that occurs during controlled nitroglycerin-induced hypotensive anesthesia in FESS. However, ivabradine was more effective with a higher safety profile, this may be a potential advantage of ivabradine in patients with contraindication to propranolol