The Effect of Antihypertensive Agents Concerning With Hemodynamics and Reduction of Anaesthetics in Orthognathic Surgery

For those who receive hypotensive anesthesia in orthognathic surgeries, the investigators premedicate with anti-hypertensive agent so that it decreases the occurence of tachycardia and the rebound hypertension due to hypotensive anesthesia, enabling us to compare hemodynamic stability and reduction of anesthetic agents during the operation.

Inclusion Criteria:

1. ASA class I-II
2. obtaining written informed consent from the parents
3. aged 18-29 years who were undergoing orthognathic surgery.

Exclusion Criteria:

1. Hypertension patients with anti-hypertensive agents
2. chronic renal failure or End stage renal disease patients.
3. renal artery stenosis history.
4. Patients who are with medication due to systemic disease.
5. symptomatic asthma
6. Drug hyperactivity
7. neurological or psychiatric illnesses
8. mental retardation
9. patients who can't read the consent form due to illiterate or foreigner