change of plan

In General anesthesia, two main ways of pain control are used intra-operatively, one is opioids, the other is epidural. Many colleges prefer using epidural analgesia because it is potent and more effective , and also the benefits of stress block, less depression of breath. however, the epidural technique often causes more drop of blood pressure, especially in dehydrated patients. The investigators designed the trial to see if the benefit weigh out the potential risk of epidural in isolated hypertensive patients.

Inclusion Criteria:

- adults aged 50-70 with isolated systolic hypertension .

Exclusion Criteria:

• age < 50 yr, ASA grade IV, severe cardiac or pulmonary insufficiency (FEV1 < 1 litre) , malignant hypertension, psychiatric illness (intake of psychiatric medication other than selective serotonin re-uptake inhibitors), diastolic blood pressure more than 110 mmHg. emergency surgery, coagulopathy, significant renal and hepatic dysfunction (creatinine > 50% or liver enzymes > 50% upper limit of normal values)

adults aged 50-70 with isolated systolic hypertension .