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  • A beta-blocker is contraindicated in this patient with a history of bronchial asthma and active rhonchi. Otherwise, IV nitroprusside and a beta-blocker would have been the combination of choice.
    • Beta-blockers reduce the pulsatile aortic flow (dp/dt).
    • If not contraindicated, the following beta-blockers can be used:
    • Propranolol IV (0.15 mg/kg given over a 5 minute period and repeated, as needed, to maintain the pulse at 60/min.
    • The short acting esmolol may be used IV as a (approximately 0.5-1 mg/kg) bolus dose over 30-60 seconds followed by a 150 mcg/kg/min infusion, if necessary. Adjust the infusion rate as required up to 300 mcg/kg/min to maintain the desired heart rate and/or blood pressure. If tolerated, other beta-blockers may be substituted.
    • IV metoprolol 1 mg q 1-3 min for maximum of 5 mg loading dose may be given in patients with questionable bronchospastic disease. The dose may be repeated, as needed.
  • IV labetolol may be successfully used as a single agent in the treatment of acute aortic dissection. 20 mg labetalol (which corresponds to 0.25 mg/kg for an 80 kg patient) by slow intravenous injection over a 2-minute period. Additional injections of 20 mg or 80 mg can be given at 10-minute intervals until a desired supine blood pressure and pulse rate is achieved or a total of 300 mg labetalol HCl has been injected. The maximum effect usually occurs within 5 minutes of each injection.
    Other agents employed in the treatment of acute aortic dissection are:
  • IV nitroprusside (50 mg in 1000 ml 5% D/W) may be started at 0.5 ml/min and increased by 0.5ml/min q 5 min until BP is adequately controlled. Check thiocyanate levels if treatment is continued for 48 hours. Stop infusion if the level reaches 10 mg/dl
  • IV trimethaphan (1-2 mg/ml) reduces LV contractility and may be infused (with the patient in a semi-Fowler position) as a single agent when nitroprusside and beta-blockers are contraindicated or not tolerated. The drug is associated with sympathoplegia (blurred vision, urinary retension and orthostatic hypotension) and rapid tolerance.
  • IV fenoldopam (0.1-1.6 ug/kg/min) may also be used for controlling hypertension
  • IV reserpine (0.1-0.2 mg) may be used if beta-blockers are contra-indicated
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