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RUSH – Rapid Ultrasound in SHock.

In EM2 on April 20, 2011 at 1:00 am

Here’s a pretty amazing article/protocol that serves as a guide to help the EP(emergency physician) in integrating resuscitative ultrasound early in the care of the undifferentiated hypotensive medical patient.

I suggest everyone reads this article. It provides a great review of shock, explains the concepts in some details and reviews ultrasound techniques . Here’s the general gist…

Classifications of Shock.

1. Hypovolemic shock – e.g in trauma with massive hemorrhage, internal blood loss (GI Bleed, AAA rupture) or loss of body fluids (vomiting, diarrhea)

2. Cardiogenic shock – e.g cardiomyopathy, myocardial infarction, acute valvular failure.

3. Distributive shock – e.g sepsis, anaphylaxis, neurogenic shock

4. Obstructive shock – e.g cardiac tamponade, large pulmonary embolism, tension pneumothorax.

RUSH exam – the shock ultrasound protocol

3steps: 1. the pump, 2. the tank, 3. the pipes. 

1. The pump – this refers to the heart i.e the patients cardiac status. A bedside echo can be use to evaluate the pericardium, cardiac contractility, and heart strain.

4views: parasternal long, short, apical 4view and subxiphoid view.

Contractility – the ‘squeeze’ of the heart. A normal healthy heart should have a large amount of change between diastole to systole i.e. a vigorously squeezing heart should almost obliterate the ventricular cavity during systole. Therefore with ultrasound(US), a poorly contracting heart can be easily visualized as moving little between the cardiac cycle. The EP can tell if the contractility is good, intermediate or poor. The focus is not necessarily to identify wall motion abnormality. Also knowing the strength of left ventricular (LV) contractility can help give a better idea of how much fluid the heart can tolerate before signs of overload become apparent. An enlarged LV that’s significantly dilated can lead to diagnosis of left heart failure/systolic failure.

The pericardium – an apparent pericardial effusion with signs of right ventricular(RV) collapse indicate a tamponade physiology. Ultrasound should also be used in performing emergent pericardiocentesis at the point of maximum fluid collection.

Heart strain – An enlarged RA (right atrium) or RV relative to the LV indicates that there’s a strain in the pulmonary system, likely a massive central pulmonary embolus, leading to acute dilation of the right ventricle. In the scenario of a hypotensive patient, thrombolysis may be considered.

2. The tank – this involves evaluation of the IVC and IJ to assess how ‘full’ they are in terms of size and collapse with inspiration.

View: epigastric long axis view of the IVC.

In normal physiology, the IVC collapses with inspiration secondary to increasing intra-thoracic pressure. This respiratory variation can be augmented with forceful inspiration i.e. ‘the sniff test’. A small caliber (<2cm) IVC with more than 50% collapse on inspiration correlates roughly with a CVP of <10cm H2O – this may indicate a hypovolemic/distributive shock state. A larger caliber (>2cm) IVC with less than 50% collapse on inspiration roughly correlates with a CVP of >10cmH2O – this may indicate more of a cardiogenic/obstructive shock state.

**this physiology is skewed in patients who are intubated or in patients who received vasodilators or diuretics prior.

Ultrasound can also evaluate tank leakiness (with a FAST exam looking for intra-abdominal fluid), tank compromise (as in a pneumothorax) or tank overload (as in pulmonary edema)

3. The pipes – US views of major arteries and veins can identify immediately like threatening i.e. in pipe Rupture as in a massive AAA (abdominal aortic aneurysm) or a aortic dissection. Venous obstruction can also be evaluated with compression sonography of deep veins of the lower extremities (DVT)

Find the full article:

The RUSH Exam: Rapid Ultrasound in SHock in the Evaluation of the Critically lll Emergency Medicine Clinics of North America – Volume 28, Issue 1 (February 2010) 29-56

ICH

In Uncategorized on April 15, 2011 at 3:28 am

63 yo F presents with acute onset of confusion and mild agitation while at outpatient ultrasound testing about 30mins prior to arrival. She complaints of a headache. denies any trauma or focal deficits. no recent illness.  PMHx : HTN, DM, GERD, HL, DVT on coumadin. no hx of CVA.

BP@ 210/115, HR 90, RR 20, 100% on room air. Afebrile.

Physical Exam: GCS – 14(E4V4M6), AOx3, mildly agitated, CN2-12 intact, 5/5 strength in all extremities, normal sensory exam. Remaining physical exam is unremarkable.

CT showed….

There is a hemorrhagic infarct in the left parieto-occipital region. There is mass effect on the sulci in this region. There is mass effect on the left occipital horn. The region of hemorrhage measures 2.7 x 6 cm. Chronic periventricular ischemic changes.

Teaching Points: ED management of Intracerebral Hemorrhage (ICH)

Risk Factors: Hypertension, Advanced age, more common in non-whites and males. Other risks: coagulation disorders, vascular malformations, hx of cva, brain tumor, drug abuse, use of thrombolytics/anticoagulates.

Critical actions for ICH management

Table 1 NINDS* and ACLS** Recommended Stroke Evaluation Time Benchmarks for Potential Thrombolysis Candidate

Time Interval Time Target
Door to doctor 10 min
Access to neurologic expertise 15 min
Door to CT scan completion 25 min
Door to CT scan interpretation 45 min
Door to treatment 60 min
Admission to stroke unit or ICU 3 h
*National Institute of Neurologic Disorders and Stroke**Advanced Cardiac Life Support guidelines

1. ABCDE – airway, breathing, circulation, disability (GCS, neurological exam), exposure (signs of trauma)

When to intubate? – as always, when there’s inadequate oxygenation, ventilation or inability to protect airway/impending loss of airway. In this case, look for depressed mental status(esp loss of gag reflex), signs of impending herniation.

REM: Transtentorial (initial signs are decreasing consciousness, coma, stupor, miotic but reactive pupil, cheyenne-stokes respiration, decorticate/Flexor posturing; as herniation progresses, pupils become fixed and dilated, posturing becomes decerebrate/extensor, Cushing’s triad manifests- [htn, bradycardia, irregular respirations], pt becomes comatose and progresses to death); Uncal (ipsilateral CN3 palsy ), Cerebella Herniation.

2. Blood pressure control

Theoretically, goal of BP control is to limit the rate of bleeding within small vessels and arterioles. However, cerebral perfusion pressure must be maintained and over-aggressive BP control is NOT advised. Goal CPP=70mmHg. Goal MAP about 90-120mmHg.

Table 2. Blood Pressure Management in ICH

Elevated blood pressure (some suggested medications)


Labetalol 5–100 mg/h by intermittent bolus doses of 10–40 mg or continuous drip (2–8 mg/min)
Esmolol 500 µg/kg as a load; maintenance use, 50–200 µg · kg-1 · min-1
Nitroprusside 0.5–10 µg · kg-1 · min-1
Hydralazine 10–20 mg Q 4–6 h
Enalapril 0.625–1.2 mg Q 6 h as needed
The following algorithm adapted from guidelines for antihypertensive therapy95 in patients with acute stroke may be used in the first few hours of ICH (level of evidence V, grade C recommendation):


1. If systolic BP is >230 mm Hg or diastolic BP >140 mm Hg on 2 readings 5 minutes apart, institute nitroprusside.


2. If systolic BP is 180 to 230 mm Hg, diastolic BP 105 to 140 mm Hg, or mean arterial BP =” border=”0″ />130 mm Hg on 2 readings 20 minutes apart, institute intravenous labetalol, esmolol, enalapril, or other smaller doses of easily titratable intravenous medications such as diltiazem, lisinopril, or verapamil.


3. If systolic BP is <180 mm Hg and diastolic BP <105 mm Hg, defer antihypertensive therapy. Choice of medication depends on other medical contraindications (eg, avoid labetalol in patients with asthma).


4. If ICP monitoring is available, cerebral perfusion pressure should be kept at >70 mm Hg.


Low blood pressure


Volume replenishment is the first line of approach. Isotonic saline or colloids can be used and monitored with central venous pressure or pulmonary artery wedge pressure. If hypotension persists after correction of volume deficit, continuous infusions of pressors should be considered, particularly for low systolic blood pressure such as <90 mm Hg.


Phenylephrine 2–10 µg · kg-1 · min-1
Dopamine 2–20 µg · kg-1 · min-1
Norepinephrine Titrate from 0.05–0.2 µg · kg-1 · min-1

3. Reverse anticoagulation

FFP(contains all coagulation factors without the RBC, platelets or WBC), dose is typically 10cc/kg and 1unit=250ml. therefore for a 70kg patient – 700cc = 2.8units. Initial dose is about 4units because it will increase factors by about 10% which is what is needed to show a significant change in coagulation status (assuming normal platelet function). INR should be rechecked 1hr after replacement.

Platelets – initial dose about 4-6units

Vit K – IV 2-5mg.

4. Neurosurgical evaluation

the ultimate disposition of the patient will likely be an intensive care unit under the management of neurosurgeons (regardless of if an immediate surgical procedure is planned). Concise and immediate communication is important especially if the patient is to be transferred to a different institution for higher level care.

5. Seizure Prophylaxis

With phenytoin or keppra, usually used for about 1mth and then discontinued if no seizure activities within that time.

***Nimotop (nimodipine) – theoretically improves vasospasm secondary to Subarachinoid hemorrhage, and thus may prevent subsequent ischemia. Preferred route is PO***

Outcome: IV Esmolol was started to maintain her MAP at 120.
Patient was given 4units of FFP and IV VitK. Arrangements were made for her transfer to a university hospital as neurosurgery was unavailable at this small community ED. She maintained her airway without significant decline in her mental status and thus was not intubated prior to transfer.  IV keppra was given for seizure prophylaxis. 

References

http://stroke.ahajournals.org/cgi/content/full/30/4/905