UMEM Educational Pearls

The most common valvulopathy after blunt chest trauma is acute aortic insufficiency. These patients will present with a new diastolic murmur. Stability depends on the degree of AI. On the other hand, if a chest trauma patient presents with a new systolic murmur, think about acute septal rupture. These patients are much more often unstable, or may die before arrival. These diagnoses may be missed in the unstable patient because physicians focus on the abdomen in the unstable patient. Pay attention to the heart sounds also!

Calcium's main effect on the ECG appears to be on the duration of the ST segment, such that: 1. Hypercalcemia shortens the ST segment, producing also a short QTc. 2. Hypocalcemia prolongs the ST segment, producing also a long QTc. As an aside, there are only three conditions in which a short QTc is typically noted: hypercalcemia, digitalis toxicity, and a recently described syndrome that causes sudden death--"the short QT syndrome" (in which the QTc may be < 300ms...that's REALLY short!). As another aside, there are only two conditions that prolong the QTc via prolongation of the ST segment--hypocalcemia and hypothermia.

Infective endocarditis (IE) The most common overall cause of IE is Streptococcus viridans. The most common cause of IE in injection drug users is Staphylococcus aureus. The most common cause of IE in patients with prosthetic valves is also Staphylococcus species; in the first two months postop coag-negative Staphylococcus predominates, and after that the most common causes are Staphylococcus aureus, Streptococcus viridans, and enterococcus. In treating IE of prosthetic valves and/or in injection drug users, the addition of rifampin to the standard regimen of nafcillin/vancomycin + gentamycin is often recommended in order to add additional gram positive coverage.

Helpful clues to distinguishing pericarditis vs. STEMI Pericarditis: PR depression in multiple leads, PR elevation > 2 mm in aVR; friction rub (specific though not sensitive) Remember that PR depression mainly only shows up in viral pericarditis, not other types STEMI: horizontal or convex upwards (like a tombstone) STE, ST depression in any lead aside from aVR and V1, STE in III > II

Be alert for cyanide toxicity when using sodium nitroprusside * Toxicity from sodium nitroprusside can be seen in as little as 2-4 hours with rates > 4.0 mcg/kg/min * Patients with hepatic and renal dysfunction are at greatest risk * Clinical signs of toxicity include altered mental status (agitation, restlessness), tachycardia, ventricular arrhythmias, and eventually hypotension * The classic anion-gap metabolic acidosis is a pre-terminal event - do not wait for this to develop to raise suspicion of toxicity! Reference: Marcucci L, ed. Avoiding common ICU errors. Philadelphia; Lippincott Williams & Wilkins; 2007:148-9.