الفهرس 
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Abstract
Hypertension is one of the most frequent forms of co-morbidity encountered by the anaesthetist. The overall number of adults with hypertension was recently predicted to exceed 1.5 billion by 2025. This increase is possibly secondary to the aging of the world population and the rapidly rising epidemic of obesity in both developed and developing countries.
Induction of general anaesthesia and endotracheal intubation are often periods of haemodynamic instability for hypertensive patients. Regardless of the level of preoperative blood pressure control, many patients with hypertension display an accentuated hypotensive response to induction of anaesthesia, followed by an exaggerated hypertensive response to intubation.
The hypotensive response at induction of general anaesthesia may reflect the additive circulatory depressant effects of the rapidly acting intravenous anaesthetic agents and antihypertensive agents. Many, if not most, antihypertensive agents and general anaesthtics are vasodilators, cardiac depressants, or both. In addition, many hypertensive patients are already volume depleted.
Laryngoscopy and intubation are associated with cardiovascular changes such as hypertension, tachycardia, dysrhythmias and even myocardial ischemia, as well as increased circulating catecholamines and may lead to cerebral hemorrhage. Usually these changes are well tolerated by healthy individuals; however these changes may be fatal in hypertensive patients.
Several techniques have been proposed to prevent or attenuate the haemodynamic responses following laryngoscopy and intubation, such as deepening of anaesthesia, pretreatment with vasodilators such as nitroglycerin, beta-blockers, calcium channel blockers, opioids and magnesium sulphate.