Hypertensive Emergencies
Definition: Severe hypertension (SBP >160, DBP>110) associated with end-organ dysfunction as manifested by, but not limited to, intracerebral hemorrhage, retinopathy, acute renal failure, pulmonary edema, myocardial ischemia, infarction, dissection.
Treatment:
Nitroprusside:
- Initial dose: 0.25 – 0.5 mg/kg/min, increase by same increment every 2-3 minutes until desired effect
- Maximum dose: 8-10 mg/kg/min (not for longer than 10 minutes)
- Will cause tachyphylaxis, avoid in renal failure
Nitroglycerin
- Initial dose: 10mcg/min, increase by 5-10 mcg/min every 5-10 minutes
- Maximum dose: 200 mg/min
Clevidipine
- Initial dose: 1mg/hour, double rate every 90 seconds until close to goal, then increase rate every 5-10 minutes as needed
- Maximum dose: 21 mg/hour
Nicardipine
- Initial dose: 5mg/hour, increase by 2.5mg/hour every 5-15 minutes
- Maximum dose: 15mg/hour
- May cause tachycardia, local phlebitis
Fenoldopam
- Initial dose: 0.1 mcg/kg/min, increase by 0.05 – 0.1 mcg/kg/min every 15 minutes
- Maximum dose: 1.6 mcg/kg/min
- Caution in glaucoma
Labetalol
- Bolus dose: 20mg IV, double dose at 10-minute intervals to max of 80mg
- Continous: 2-10mg/min, if titrating, increase by 1mg/min every 10 minutes
- Not to exceed maximum dose of 300mg.
- IV b:a ratio is 7:1
Esmolol
- Bolus dose: 500m/kg
- Continous dose: 25 – 300 mg/kg/min
- Titration: Increase by 50mg/kg.min every 4 minutes
- Bolus with every rate increase
Enalapril
- Initial dose: 1.25mg.
- Maximum dose: 5mg every 6 hours
- Avoid in renal failure
Pearls:
- Consider placement of an arterial line for more precise monitoring.
- Set an initial goal to reduce MAP by 20%.
- Do not exceed a MAP reduction >25% in 24 hours.
- Volume depletion is common; administration of a diuretic in conjunction with an anti-hypertensive agent can lead to a precipitous drop in BP.
- Be wary of over-zealous correction, as this can lead to organ hypo-perfusion.
References:
- Marik PE, Rivera R. Hypertensive emergencies: an update. Curr Opin Crit Care 2011; 17:569-80.
- Flanigan, J., & Vitberg, D. (2006). Hypertensive emergency and severe hypertension: What to treat, who to treat and how to treat. Medical Clinics of North America, 90, 439–451.