Hypertensive emergency
A hypertensive emergency is a severe elevation in blood pressure (BP), usually above 220/140 mmHg, that is associated with acute end-organ damage or dysfunction, such as acute pulmonary oedema, acute kidney failure, hypertensive encephalopathy, papilloedema or cerebrovascular haemorrhage.
A hypertensive emergency is a life-threatening event. Arrange immediate transport to hospital by ambulance for treatment in an emergency department, intensive care unit or coronary care unit.
Insertion of an arterial line for invasive BP monitoring enables immediate recognition of fluctuations in BP, and is recommended in all patients experiencing a hypertensive emergency. If an arterial line cannot be inserted, check BP at least every 5 minutes using a noninvasive method.
Evidence to guide the initial BP target in a hypertensive emergency is lacking, but a reasonable initial goal is to reduce BP by no more than 25% within the first 2 hours. Adapt the initial target to the extent of BP elevation and the clinical condition or type of end-organ damage or dysfunction present. Advice from a senior clinician is often needed to determine the initial target.
Use an intravenous infusion of a drug that has a rapid onset and short duration of action. This enables rapid control of BP, and prevents a precipitous drop in BP that may be difficult to correct.
The choice of drug in a hypertensive emergency depends primarily on the clinical condition (see Conditions associated with hypertensive emergencies). Other considerations include:
- contraindications
- current drug therapy
- pregnancy
- clinician familiarity with the drug
- drug availability
- local guidelines and protocols.
If an intravenous infusion is not immediately available (eg it needs to be sourced or prepared), consider using intermittent intravenous doses in the interim. Suitable regimens for initial intermittent intravenous doses include:
1hydralazine 1 mg intravenously, repeated every minute as required up to a maximum total dose of 10 mg hydralazine hydralazine hydralazine
OR
2clonidine 150 micrograms intravenously, repeated every 3 to 6 hours as required to a maximum total dose of 750 micrograms clonidine clonidine clonidine
OR
2metoprolol tartrate 1 mg by rapid intravenous injection, repeated every minute as required up to a maximum total dose of 5 mg. metoprolol metoprolol metoprolol
Other drugs such as atenolol, labetalol or nimodipine, can be used.
The choice of drug for an intravenous infusion in a hypertensive emergency depends primarily on the clinical condition (see Conditions associated with hypertensive emergencies). Titrate the dose of the infusion to achieve and maintain BP in the target range. Dose according to local hospital protocols; if a local protocol is not available, suitable options for an intravenous infusion are:
1sodium nitroprusside 0.3 micrograms/kg/minute by intravenous infusion, increasing by 0.5 micrograms/kg/minute every 5 minutes, up to 10 micrograms/kg/minute1 sodium nitroprusside sodium nitroprusside sodium nitroprusside
OR
2esmolol 500 micrograms/kg intravenously, over 1 minute, followed by 50 to 200 micrograms/kg/minute by intravenous infusion esmolol esmolol esmolol
OR
2glyceryl trinitrate 10 micrograms/minute by intravenous infusion, increasing by 5 micrograms/minute every 5 minutes, up to 100 micrograms/minute glyceryl trinitrate glyceryl trinitrate glyceryl trinitrate
OR
2labetalol 20 mg intravenously, over 2 minutes, repeated after 10 minutes if there is no or little BP reduction. Follow by 20 mg/hour by intravenous infusion, increasing by 20 mg/hour every 15 minutes, up to maximum rate 160 mg/hour. Usual effective total dose 50 to 200 mg2. labetalol labetalol labetalol
Sodium nitroprusside begins to reduce BP within minutes, but requires intensive ongoing monitoring, blood testing and specialist input. It should usually be avoided in pregnancy and severe kidney or liver impairment.
If more rapid control of BP is needed, or target BP is not achieved at the maximum dosages recommended above, seek expert advice.
Once the hypertensive emergency is controlled or oral therapy has been started (either BP-lowering therapy or specific therapy to manage the associated clinical condition), the infusion can be weaned with specialist input and close monitoring.