Physician's Guide to MDCalc & Clinical Decision Making

Believe it or not, there are some things your attendings don’t know. New evidence is published every day, but there’s a lot of noise among the signal. Got a patient presenting with syncope who you want to risk-stratify after doing a basic workup? Search for “syncope” and find the Canadian Syncope Risk Score, and in ~2 minutes you can calculate your individual patient’s risk for a serious adverse event, and in the Evidence section, see that it’s based on a Canadian prospective cohort study of about 4,000 syncope patients in 6 EDs, and that “serious adverse events” included death, arrhythmia, myocardial infarction, and others.

“His vitals are within normal limits, and the exam is unremarkable except he has a little bit of abdominal tenderness. But it’s not rigid or anything.”

“He is tachycardic to 91 and blood pressure is 100/60 which is low for him since the last time he was here, his BP was consistently above 140 systolic on three separate readings. Abdominal exam is significant for epigastric tenderness without rebound or guarding.”

“Labs are: sodium 140, potassium 3, chloride 100, bicarb 25, BUN 100, creatinine 3, glucose 120, hemoglobin 10…”

“Labs show acute kidney injury with a creatinine of 3.0, above his baseline of 1.3, and his hematocrit has dropped to 30 from 39 the last time he was here. Also of note, his MELD Score is 27, which correlates with a 3-month mortality of 19.6%".

Gastroenterology

1. Is the patient stable? Securing the airway, supporting hemodynamics, and ensuring appropriate/adequate monitoring is the most important first step. It is not safe to go ahead with even considering endoscopy until this is taken care of.
2. What is the hemoglobin? GI is often called before a CBC is drawn. Having a hemoglobin is very important for our planning of when to do the endoscopy. It is helpful to know if the current Hgb is really different than their baseline (or a recent CBC).
3. INR and PTT should be drawn.
4. Is the patient on anticoagulants or antiplatelet agents?When was their last dose?

5. What is the nature of the bleeding? I'm much more worried about large volume hematemesis with instability compared to coffee ground emesis.
6. When did they last eat? This will also affect when the patient can be scoped. If there is significant bleeding, make them NPO right away.
7. Do they have comorbidities that could put them at increased risk of endoscopy (like significant cardiac or pulmonary disease) or that may give a clue as to the cause of their bleeding (i.e., variceal bleeding in cirrhotics)?
8. Has medical therapy (IV PPI, IV octreotide in variceal bleeding) been started?

Neurology

1. Age and sex.
2. Super brief medical history, especially previous stroke and residual neuro sequelae that might help the neurologist differentiate mimic vs. stroke.
3. Last known well time (LKW) - this is the single most important detail - and how the information was obtained (e.g. witnessed, or last known well).
4. Brief presenting symptoms (e.g. "right-sided weakness and aphasia").
5. NIHSS Score and what deficits patient was given points on scale for.

6. If patient is tPA candidate: whether or not any contraindications to tPA exist, like history of ICH or on warfarin.
7. CT head and or CTA/CTP results
8. If CTA results, whether there is a proximal LVO or not*.
9. If CTP results, location and size (volume) of the penumbra and core infarcts, and whether there is a mismatch between the two**.

Neurology cont.

Ideally, the conversation should be held with the neurologist as the patient is rolling through the CT scanner so that tPA can be given as immediately as possible after a negative CT scan (for bleeding), and if CTA is necessary, tPA should be given in the scanner, obviously institutional parameters allowing, followed by CTA.

*Trials have demonstrated efficacy in proximal LVOs and not distal, as well as the location of the LVO if present (e.g. "left M1 segment of the middle cerebral artery").

**Most of the time this will be read-out by a neuroradiologist (e.g. "perfusion imaging shows an acute infarct of X mL over the anterior L MCA territory with large surrounding penumbra"). Generally speaking (and this is not 100% academically rigorous) patients with large penumbra-to-core mismatch presenting <24 hours from LKW are deemed to be interventional neuroradiology candidates. More specifically, there are cut-offs for size for the core and penumbra that constitute who is a good candidate/not but I would leave that to the neurologist/INR specialist.