Hypertension in the critically ill patient.
OBJECTIVE
To review the management of persistent hypertension and hypertensive crisis in the critically ill patient.


METHODS
A review of articles reported on hypertension and the critically ill patient.


RESULTS
Hypertension is defined as a basal systolic blood pressure of greater than 140 mmHg or diastolic blood pressure of greater than 90 mmHg (MAP > 105 mmHg), irrespective of age and is based on the average of two or more readings on two or more occasions over a period of four weeks. While a mean arterial pressure in the critically ill up to a value of 135 mmHg may be tolerated for some hours, in patients with dissecting aortic aneurysm, cardiac failure, angina, acute myocardial infarction, pre-eclampsia and following cardiac, vascular or cerebral surgery a mean arterial blood pressure of > 90 mmHg or greater should be lowered by up to 30% urgently. A hypertensive crisis may be defined as a MAP > 160 mmHg and can be caused by phaeochromocytoma, sympathomimetic overdose, malignant hypertension or autonomic hyper-reactivity secondary to tetanus. Treatment requires direct intra-arterial monitoring and an initial reduction in mean arterial pressure by no greater than 30%. While management of the primary condition (e.g. surgical removal of a phaeochromocytoma, delivery or termination of the pregnancy) may also be necessary, infusions of sodium nitroprusside, phentolamine, hydralazine or esmolol usually require supplementation with oral agents (e.g. angiotensin-converting enzyme inhibitors, beta-adrenergic receptor antagonists and calcium-channel blockers) for long-term management.


CONCLUSIONS
A mean arterial pressure in the critically ill is often tolerated up to a value of 135 mmHg for some hours. However in some disorders (e.g. dissecting aortic aneurysm, cardiac failure, angina, acute myocardial infarction, pre-eclampsia or eclampsia and following cardiac, vascular or cerebral surgery) a mean arterial blood pressure of 90 mmHg or greater should be treated urgently.
Santhi
R
R
Department of Critical Care Medicine, Flinders University of South Australia, Adelaide, South Australia.
Worthley
Lindsay I G
LI