الفهرس 
Applied anatomy of the noseOnly 14 pages are availabe for public view
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Abstract
Controlled hypotension during general anesthesia aims to lower the mean arterial blood pressure (MAP) to values between 55 and 65 mmHg in patients with normal blood pressure, with the goal of significantly reducing blood loss by maintaining it at this level throughout the operation process. Controlled hypotension is frequently used for obtaining better exposure during nasal surgery as small bleeding areas can reduce operative visibility and result in destruction of surrounding structures. Various agents (e.g., magnesium sulphate, sodium nitroprusside, nicardipine, nitroglycrin, esmolol, α2-agonist, labetalol, and high doses of potent inhaled anesthetics) have been used to achieve controlled hypotension. Dexmedetomidine is potent highly selective α2 adrenergic receptor agonism. It has sedative, analgesic and anesthetic sparing effect, and sympatholytic properties. The central and peripheral sympatholytic action of (DEX) is mediated by α2 adrenergic receptor and is manifested by dose-dependent decrease in arterial blood pressure, heart rate, cardiac output and norepinephrine release.
Propofol is a gentle, safe, non-opiate medication with rapid smooth action, and quick offset. It is exceedingly
Summary and Conclusion
102
unlikely to cause any allergic reaction, and does not cause nausea. In the proper hands, it is easily controlled, and can be used for mild sedation to general anesthesia. It can be used for very short operations, lasting a few minutes, to long procedures lasting many hours. Ideally, hypotensive agents should be easy to administer, have a short time to onset, have effects that disappear quickly when administration is discontinued, have rapid elimination without toxic metabolites, have negligible effects on vital organs, and have predictable and dose-dependant effect. This study was done to compare the efficacy and safety of dexmedetomidine or propofol as a hypotensive agent in rhinoplasty with attention on the amount of blood loss, quality of the surgical field, hemodynamics, recovery profile, and tolerability in adult patients.Fourty patients, of ASA I and II were randomized either to receive dexmedetomidine or propofol in two equal groups. The following parameters were assessed between the 2 groups: the amount of blood loss, quality of surgical field, surgeon satisfaction, hemodynamics variables in the form of MAP and HR were recorded at (baseline, after anesthetic induction & at 15, 30, 60, 90, 120 minutes) also at 15, 30, 60 minutes postoperatively.
Summary and Conclusion
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Also the cumulative dose of fentanyl, recovery profile, postoperative sedation using Ramsay sedation score at 15,30,60 minutes, 1st analgesia request and occurrence of side effects like hypotension, bradycardia, nausea and vomiting. This study was compared with other studies carried to compare between the effect of using dexmedetomidine and propofol in controlled hypotensive anesthesia. Some results matched with the results of this study and some didn‟t match. The results of the present study showed that dexmedetomidine or propofol with sevoflurane are safe agents for controlled hypotension and both are effective in providing ideal surgical field during rhinoplasty. Compared with propofol, dexmedetomidine offers the advantage of decreased intraoperative fentanyl consumption with prolonged postoperative analgesia.