Efficacy of Oral Diltiazem on the Intraoperative Bleeding in Functional Endoscopic Sinus Surgery

Functional endoscopic sinus surgery (FESS) is a minimally invasive technique used to restore sinus ventilation and function in patients with recurrent acute or chronic infective sinusitis in whom medical therapy has failed.

Continued bleeding into the surgical field during FESS not only impairs endoscopic vision but can lead to complications.

Controlled hypotension is a technique used to limit intraoperative blood loss to provide the best possible field for surgery. The physiological principle which underlies hypotensive anesthesia is a natural survival mechanism. When profuse bleeding occurs, the blood pressure drops. This drop leads to a reduction or cessation of the bleeding, blood pressure stabilization, and recovery. Accordingly, reducing the patient's blood pressure during surgery can potentially reduce overall bleeding. Since bleeding in the surgical field is also reduced, the surgical field operating conditions are improved In hypotensive anesthesia, the patient's baseline mean arterial pressure (MAP) is reduced by 30 %. Consequently, the systolic blood pressure values are about 80-90mmHg and the MAP is reduced to 50- 65mmHg.

Hypotensive anesthesia is considered to be a suitable anesthetic technique for those patients who will be undergoing spinal surgery, hip or knee arthroplasty, craniosynostosis, hepatic resections, and major maxillofacial operations. Benefits for controlled hypotension for FESS include the reduction in blood loss with improved quality of the surgical field.

Various agent's anesthetic agents, analgesics, and hypotensive drugs, that have been used for achieving hypotensive anesthesia:

1. Volatile Anesthetic Agents. Most anesthetic agents have a hypotensive effect such as isoflurane, sevoflurane, and desflurane, high concentrations are required to achieve a significant reduction in intraoperative bleeding, and these concentrations may lead to hepatic or renal injury.
2. Propofol. has a potent hypotensive capability, but normal blood pressure will be rapidly restored when the propofol infusion is discontinued. Although a short-term propofol infusion is safe, a long-term Propofol infusion can cause propofol infusion syndrome in children.
3. Alfentanil, Sufentanil, and Remifentanil. potent synthetic and short-acting opioid drugs, Since the recovery times from this type of anesthesia are also short, they are widely used for hypotensive anesthesia. d.Nitrates. SNP and NTG are two very potent hypotensive agents that are commonly used for inducing hypotensive anesthesia. Reflex tachycardia is an unwanted effect which often occurs with nitrates administration and can be prevented by a small dose of the beta-adrenoceptor antagonist, such as esmolol or propranolol premedication. e-beta-Adrenoceptor Antagonists. They effectively used for inducing hypotensive anesthesia when administered either as a single hypotensive agent or in combination with SNP. Nonselective beta-antagonists, such as labetalol, may cause bronchoconstriction and should be avoided in asthmatic patients. The hypotensive action of beta-adrenoceptor antagonists is achieved by reducing cardiac output. So, not suitable for the patient with underlying heart failure. f-Calcium Channel Antagonists. such as nifedipine or nicardipine, are commonly used as hypotensive drugs.

Diltiazem, a calcium channel blocker, blocks the influx of calcium into smooth muscle cells and cardiac muscle cells. This causes relaxation of the muscle, thereby causing reduced arteriolar tone and fall in blood pressure.

Tranexamic acid is a synthetic amino acid that inhibits fibrinolysis, which reduces blood loss and the need for blood transfusion in total knee arthroplasty, spine surgery, and cardiac surgery. It has seen wide application in a variety of surgical procedures since then.