Clinical Decision Rules

Question 1

What is the PERC rule?

Answer 1

Apply to LOW risk patients by clinical gestalt or wells criteria.

1. Age < 50 years
2. HR < 100 bpm
3. Room air oxygen saturation > 94%
4. No prior history of DVT or PE
5. No recent trauma or surgery
6. No hemoptysis
7. No exogenous estrogen
8. No clinical signs suggestive of DVT

    H – Hormone (estrogen) use/HR >100
    A – Age > 50
    D – DVT or PE history (have they HAD CLOTS?)
    C – Coughing blood
    L – Leg swelling disparity
    O – O2 sats < 95%, OCP
    T – Tachycardia (>100bpm)/Trauma/sx last 4 weeks
    S – Surgery or Trauma (recent)

If ALL criteria are met, then the patient can be called “PERC negative.”

• Of note don’t forget to ask about pleuritic CP, family thrombophilia (non-cancerous), fam Hx PE
• ## Not validated in pregnant or postpartum patients

Question 2

What is the Wells criteria for DVT?

Answer 2

1. Active cancer (+1 point)
2. Bedridden recently >3 days or major surgery within four weeks (+1 point)
3. Calf swelling >3 cm compared to the other leg (+1 point)
4. Collateral (nonvaricose) superficial veins present (+1 point)
5. Entire leg swollen (+1 point)
6. Localized tenderness along the deep venous system (+1 point)
7. Pitting edema, greater in the symptomatic leg (+1 point)
8. Paralysis, paresis, or recent plaster immobilization of the lower extremity (+1 point)
9. Previously documented DVT (+1 point)
10. Alternative diagnosis to DVT as likely or more likely (-1 points)

Those with 0-1 points are deemed “low risk.” Combining the D-dimer with a Wells score seems to impart a low enough risk to not require further testing or the risk of empiric anticoagulation. However, there have been recent studies that question this strategy arguing that the risk is unacceptably high in this group and further that this strategy is useless in particular higher-risk subgroups (e.g. males, active malignancy, recurrent DVT).

Question 3

What is the Wells Criteria for PE?

Answer 3

1. Clinically suspected DVT — 3.0 points
2. Alternative diagnosis is less likely than PE — 3.0 points
3. Tachycardia (heart rate > 100) — 1.5 points
4. Immobilization (≥ 3d)/surgery in previous 4 wks (1.5 points)
5. History of DVT or PE — 1.5 points
6. Hemoptysis — 1.0 points
7. Malignancy (with treatment within 6 months) or palliative — 1.0 points

Traditional interpretation
Score >6.0 — High (probability 59%)
Score 2.0 to 6.0 — Moderate (probability 29%)
Score <2.0 — Low (probability 15%)

Question 4

What is the Canadian CT Head rule?

Answer 4

Age>16. Only Apply to GCS 13-15 Patients with LOC, Amnesia to the Head Injury Event, or Confusion

Major Criteria
(Signs/Symptoms Concerning for Need for Neurosurgical Intervention)
1. GCS < 15 at 2 hours post-injury
2. Suspected open or depressed skull fracture
3. Any sign of basilar skull fracture? (Hemotympanum, Racoon Eyes, Battle’s Sign, CSF oto-/rhinorrhea)
4. ≥ 2 episodes of vomiting
5. Age ≥ 65

Minor Criteria
(Additional Signs/Symptoms That Help Detect All Traumatic Intracranial Processes)
1. Retrograde Amnesia to the Event ≥ 30 minutes
2. “Dangerous” Mechanism? (Pedestrian struck by motor vehicle, Occupant ejected from motor vehicle, or Fall from > 3 feet or > 5 stairs.)

IF any criteria present than consider CT of head.

Question 5

What is the Nexus Criteria for C-spine clearance?

Answer 5

Focal Neurologic Deficit Present
Midline Spinal Tenderness Present
Altered Level of Consciousness Present
Intoxication Present
Distracting Injury Present

If NONE present can clear c-spine without imaging

Question 6

What is the Canadian C- Spine Rule?

Answer 6

1. High Risk -IF present xray (3)
   Age ≥ 65
   Extremity Paresthesias or
   Dangerous Mechanism (fall from ≥ 3ft / 5 stairs, axial load injury, high speed MVC/rollover/ejection, bicycle collision, motorized recreational vehicle)

2. Low Risk Factor Present (5)
Sitting Position in the ED
Ambulatory at any time
Delayed (not immediate onset) neck pain
No midline tenderness 
Simple rearend MVC?
MVC not simple if: pushed into traffic, hit by bus/large truck, rollover, hit by high-speed vehicle

3. Able to Actively Rotate Neck 45° left and right

If answer No to Q1, Yes to Q2,3 then can clear c-spine without imaging.

Question 7

What are the SIRS, Sepsis, Severe sepsis and Sepsis Shock criteria?

Answer 7

SIRS Criteria (≥ 2 meets SIRS definition)
Temp >38°C (100.4°F) or < 36°C (96.8°F)
Heart Rate > 90
Respiratory Rate > 20 or PaCO2 < 32 mm Hg
WBC > 12,000/mm>3, < 4,000/mm>3, or > 10% bands

Sepsis Criteria (SIRS + Source of Infection)

Severe Sepsis Criteria (Organ Dysfunction, Hypotension, or Hypoperfusion)
Lactic Acidosis, SBP <90 or SBP Drop ≥ 40 mm Hg of normal

Septic Shock Criteria
Severe Sepsis with Hypotension, despite adequate fluid resuscitation

Question 8

What is the ABCD2 criteria for stroke after TIA?

Answer 8

Age ≥ 60
BP ≥ 140/90 mmHg
Initial blood pressure reading. Either SBP > 140 or DBP > 90

Clinical Features of the TIA
Unilateral Weakness +2
Speech Disturbance without Weakness +1
Other Symptoms 0

Duration of Symptoms
<10 Minutes 0
10-59 Minutes +1
≥ 60 Minutes +2

History of Diabetes

The ABCD2 score was developed in the outpatient setting, and while it is frequently used in the Emergency Department, is not as well suited to ED patients.

Question 9

What are the Ottawa knee rules?

Answer 9

Xray if any of

1. Age> 55
2. Isolated tenderness over patella
3. Tenderness at head of fibula
4. Inability to flex knee 90 degrees
5. Inability to weight bear (4 steps) immediately AND in the ED

Question 10

What is the Ottawa foot rule?

Answer 10

Get Xray if tenderness in midfoot area and any of:

1. Tender over Navicular or 5th MT
2. Inability to weight bear immediately AND in the ED

Question 11

What is the Ottawa ankle rule?

Answer 11

Get Xray if tenderness in malleolar area and any of:

1. Tender over posterior tip of lateral or medial malleolus up 6 cm
2. Inability to weight bear immediately AND in the ED