the agent of choice, provided that the patient is not hypotensive. Volume
reduction with diureticsis also critical to lower BP and cardiac-filling pres-
sures. Noninvasive airway techniques (eg, bilevel positive airways
pressure [BiPAP], continuous positive airway pressure [CPAP])also aid
in improving oxygen exchange, reducing the work of breathing, and decreasing
left ventricular preload and afterload by raising intrathoracic pressure in the
compromised but not agonal APE patients.
(a)It is important to first address the ABCs. If infection is thought to
be the cause, then obtaining a CBC, blood cultures, and starting antibiotics
should be performed after stabilization. (b)A chest x-ray is valuable, but
initial stabilization takes priority. (c)Oxygen via nasal cannula is not suffi-
cient for this patient who is hypoxic and tachypneic. If you are suspicious
for ACS causing the CHF exacerbation, then aspirin should be adminis-
tered. (e)At this time, the patient does not require invasive airway control.
If medication and noninvasive techniques fail and the patient’s hypoxia
worsens then endotracheal intubation may be necessary.
27.The answer is e.(Rosen, p 1096.)Torsades de pointes(“twisting of
the points”) is a life-threatening uncommon variant of ventricular tachycar-
dia (VT). The ventricular rate can range from 150 to 250 beats per minute.
It may occur secondary to medications that prolong the QT interval, such as
some antipsychotics. It is also caused by electrolyte disturbances and con-
genital prolonged-QT syndrome. This congenital form typically presents in
childhood or early adulthood and is precipitated by catecholamine excess,
such as released during exercise or with the administration of certain
medications.
(a)Ventricular fibrillation is disorganized electrical activity causing no
effective contraction of the ventricles. A pulse or BP never is present with ven-
tricular fibrillation. (b)Atrial fibrillation occurs when there is disorganized
atrial activity that leads to the lack of P waves on an ECG. In general, the QRS
complex is narrow unless there is a bypass tract or bundle branch block.
(c)WPW syndrome is caused by an accessory electrical pathway (bundle of
Kent) between the atria and ventricles, which predisposes the individual to
reentry tachycardias. (d)Supraventricular tachycardias occur secondary to a
reentry circuit. Patients typically exhibit a narrow complex tachycardia on ECG.
28.The answer is c.(Tintinalli, pp 386-391.)Risk factors for venous
thromboembolism were first described by Virchow triad: hypercoagulability,
stasis, and endothelial injury.Hypercoagulability can be broadly classified
38 Emergency Medicine