Last Reviewed by Department Renal Medicine January 2007

Last reviewed by Department Renal Medicine January 2007

Treatment of hypertensive emergency

Definition

Ø Severe hypertension (SBP ≥ 200 mmHg and/or DBP ≥ 120mmHg)

Ø in association with deteriorating end organ function:

· Malignant hypertension ie. with acute retinopathy, pulmonary edema, acute renal failure.

· Hypertensive encephalopathy

· Dissecting aneurysm

· Subarachnoid haemorrhage (see ‘Management of Hypertension in Stroke’)

· Eclampsia (treat parentally if SBP ≥170mmHg and/or DBP ≥110mmHg – see ‘Management of Hypertension in Pregnancy’)

Investigations

· Creatinine, electrolytes

· Renin, aldosterone, cortisol, plasma free metanephrines

· ECG

· Urinalysis

* Start treatment prior to the availability of these results.

Management Principles

· Aim to lower BP, initially to around 160/110mmHg to avoid cerebral hypoperfusion if BP falls too quickly.

· In aortic dissection, aim for a systolic BP 100-120mmHg.

· Commence oral antihypertensive therapy as soon as a response to I/V agents is apparent; this allows the smooth transition from I/V to oral agents.

Drugs To Use

Best Choice: SODIUM NITROPRUSSIDE (SNP)

Predominantly arteriolar vasodilator

· Dose: 0.5-10 microg/kg/min ivi. Start at 0.5microg /kg/min with upward titration every few minutes until desired effect has been achieved or a maximum of 10microg/kg/min has been reached

· Preferably intra-arterial BP monitoring in monitored unit but start treatment first, insert arterial line later.

· Wrap syringe and lines in foil as SNP is light sensitive.

· Onset immediate

· Duration: 2-3 minutes

· Thiocyanate toxicity (delirium, blurred vision, tinnitus) after 1mg/kg total dose, so treatment is generally no longer than 24-48 hours

· Hepatic & renal excretion. Use no longer than 24 hrs in renal failure

· Click here for SNP infusion rates (as Word document)

Sodium nitroprusside infusion rates (ml/ hour)

4 40 mg SNP in 100 mls of 5% Dextrose = 400 microg/ml

ml / hour

Weight

(kg)

/ 0.5 / 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 / 10
40 / 3 / 6 / 12 / 18 / 24 / 30 / 36 / 42 / 48 / 54 / 60
45 / 3.5 / 7 / 13.5 / 20 / 27 / 34 / 40.5 / 47 / 54 / 61 / 67.5
50 / 4 / 7.5 / 15 / 22.5 / 30 / 37.5 / 45 / 52.5 / 60 / 67.5 / 75
55 / 4 / 8 / 16.5 / 25 / 33 / 41 / 49.5 / 58 / 66 / 74 / 82.5
60 / 4.5 / 9 / 18 / 27 / 36 / 45 / 54 / 63 / 72 / 81 / 90
65 / 5 / 10 / 19.5 / 29 / 39 / 49 / 58.5 / 68 / 78 / 88 / 97.5
70 / 5 / 10.5 / 21 / 31.5 / 42 / 52.5 / 63 / 73.5 / 84 / 94.5 / 105
75 / 5.5 / 11 / 22.5 / 33.5 / 45 / 56 / 67.5 / 79 / 90 / 101 / 112.5
80 / 6 / 12 / 24 / 36 / 48 / 60 / 72 / 84 / 96 / 108 / 120
85 / 6 / 13 / 25.5 / 38 / 51 / 64 / 76.5 / 89 / 102 / 115 / 127.5
90 / 7 / 13.5 / 27 / 40.5 / 54 / 67.5 / 81 / 94.5 / 108 / 121.5 / 135
95 / 7 / 14 / 28.5 / 42 / 57 / 71 / 85.5 / 100 / 114 / 128 / 142.5
100 / 7.5 / 15 / 30 / 45 / 60 / 75 / 90 / 105 / 120 / 135 / 150

If associated angina:

GLYCERYL TRINITRATE (GTN)

Predominantly venodilator

· Dose: 50 mg in 500 mL 5% Dextrose or Saline (i.e. 100 ug/ml) Use glass bottles and PVC free tubing

· start at 600microg (6 ml)/hr to maximum 50 ml/hr. Increase by 600microg every 3 to 5 minutes. Usual dose range is 1 to 5mg per hour

· Side effects: headaches, tachycardia, nausea, vomiting, restlessness

· This is ideal in the setting of hypertensive emergency with angina but GTN is not generally considered the best choice for parenteral treatment of hypertension.

If associated subarachnoid hemorrhage:

NIMODIPINE

· Used for subarachnoid haemorrhage, generally only given in ICU

· Dose: 1 mg/hr 1st 2 hrs with co-infusion of Hartmann’s or 5% Dextrose at 4 times the volume of nimodipine infusion.

· Increase to 2 mg/hr over 12-24 hrs

· Treat up to 14 days

· Convert to oral nimodipine 60 mg q4h for 7-14 days

· Reduce dose if hepatic insufficiency

· Interactions: valproate, cimetidine, phenobarbitone, carbamazepine, phenytoin (Consult protocol in ICU)

Other Options:

HYDRALAZINE

· 5 mg boluses ivi every 20 mins to max 20 mg

o If no response use hydralazine infusion (80 mg in 500 mL N/saline) @ 1-5 mg/hr (6-30 ml/hr)

· Side effects: Flushing, tachycardia, headache

METOPROLOL

· Dose: 5 mg bolus given over 2-3 mins

· Repeat at 5 minute intervals up to maximum 20 mg

· Monitor with ECG during treatment

· Ensure no contraindications to ß-blockers

· Excreted renally so watch for bradycardia in patients with renal failure.

ESMOLOL

· Cardio selective ß1 blocker

· Usual contraindications to ß-blockers apply

· Dose: 10mL vial (100mg/mL) diluted in 100mL Sodium Chloride 0.9% or Glucose 5% - 10mg /mL

· Loading dose of 0.5 mg/kg/min for 1 minute then 0.05 mg/kg/min and titrate to maximum dose of 0.2 mg/kg/min

· Stable over 24 hr infusion

Consistent with published guidelines: