Your
answer (D) is not the one that we were looking for. (C) is correct!
-
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
You may review the
previous question again, if you so desire, by clicking on
the left corner prior
key.
|