الفهرس 
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Abstract
Deliberate hypotension is an acceptable intraoperative technique improving surgical conditions when a bloodless operative field is needed, together with reducing blood loss and the need for blood transfusion with its concomitant hazards.
Either, a reduction in cardiac output or a decrease of systemic vascular resistance can produce normovolaemic hypotension.
Drugs with different modes of action have been used alone or in combinations to induce hypotension , these drugs may be classified depending on their mode of action into ; Ganghonic blockers (e.g. pentolinium & trimethaphane); direct-acting vasodilators (e.g.sod.nitroprusside, nitroglycerine, hydralazine, adenosine & prostaglandin El); ai- adrenergic receptor blockers (e.g. phentolamine); P- adrenergic blockers (e.g. propranolol & esmolol); 02-adrenoceptor agonists (e.g.clonidine); angiotensin-converting enzyme inhibitor (e.g. captopril) and calcium channel blockers (e.g.verapamil & nicardipine).
Induced hypotension may result in hormonal and metabolic responses.
However the major disadvantage of induced hypotension is that tissue oxygenation, which may be impaired if arterial pressure is reduced excessively to jeopardize the requirements of the vital organs