FALLS protocol…

Below is the main content discussed at an ultrasound workshop I ran this week at the Sydney HEMS Clinical Governance Day.

Whilst the bread & butter use of prehospital ultrasound would have to be an extended-FAST scan in the setting of trauma, I decided to focus more on utility of basic ECHO & lung ultrasound in the assessment of shocked medical patients.

A lot has been written about the RUSH protocol and its role in aiding the diagnosis of undifferentiated shock/hypotension. From my own experience (in initiating patient transfers, not conducting them), a source of shock is largely defined by the time an inter-hospital retrieval takes place (ie. abdominal aortic aneurysms excluded by history, examination or ED ultrasound).

When faced with the ongoing ED-based resuscitation of shocked patients (esp. those with septic shock & refractory hypotension), I find myself using a process similar to Lichtenstein’s FALLS protocol which I believe can be carried into the arena of retrieval medicine to guide ongoing therapy (and potentially alter outcomes).

The FALLS protocol.

This is a tool proposed to assist in the management of shocked patients, mainly by the use of lung ultrasound.

Firstly, it aims to exclude obstructive shock by

1. Cardiac ECHO.
   • ?tamponade
   • ?massive pulmonary embolism with right heart strain
2. Lung USS.
   • ?tension pneumothorax.

The second phase aims to assess volume status by exploiting ultrasound lung-artefact to detect interstitial syndrome (suggestive of extravascular lung water).

1. B-Profile.
   • ie. cardiogenic shock – supported by distended, non-compressing inferior vena cava & the presence of pleural effusions.
   • alternatively; signals appropriate volume replacement & a trigger to start vasopressors to maintain blood pressure.
2. A-Profile.
   • suggestive of hypovolaemic or distributive shock.
   • triggers further fluid administration.

Below are the images & ultrasound clips used in my presentation, demonstrating the significant findings at each stage of the protocol.

[DDET Cardiac tamponade…]

Early tamponade with RV diastolic collapse.

 

Massive pericardial effusion with obvious tamponade. Dx: Malignant effusion 2* to NSCLC.

 

Massive pericardial effusion with features of tamponade.
NB. the both right atrial and right ventricular diastolic collapse.

For more information on features of tamponade check out “Sequential sinister sightings…” !!

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[DDET Pulmonary embolism…]

Submassive PE.
Severe dyspnoea with A-a gradient > 500 !! Normotensive, but elevated serum troponin.

 

Massive pulmonary embolism.
Elderly male with undifferentiated shock, hypoxia and abdominal pain.

Features of right ventricular strain in PE.

1. RV:LV (end-diastolic diameter) > 0.9 – A4C or subcostal view.
2. RV end-diastolic diameter > 30mm – PLAX or PSAX view.
3. Hypokinetic RV free wall
4. Tricuspid regurgitant jet velocity > 2.6m/s
5. Paradoxical interventricular septal motion
6. McConnell’s sign – akinesia of the RV-mid free wall with normal motion at the RV apex.

For further discussion on the role of thrombolysis in pulmonary embolism check out “Two in two days…”

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[DDET Pneumothorax…]

Normal lung sliding. Comet tails + A-line artefact present.

 

Pneumothorax present. No visible comet tails, no lung sliding.

 

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[DDET B-Profile]

Bilateral B-lines [‘lung rockets’] consistent with pulmonary oedema/interstitial syndrome.

7 criteria for B-lines.

1. There is a comet-tail, vertical artefact.
2. Arises from the pleural line.
3. Moves in concert with lung sliding.
4. Does not fade.
5. Well-defined, laser like.
6. Hyperechoic.
7. Obliterates the A-lines.

In the BLUE-protocol detection of interstitial syndrome to anterior chest, bilaterally (with lung-sliding) makes the diagnosis of haemodynamic pulmonary oedema with 97% Sn & 95% Sp.

Differential diagnoses of B-lines;

• pulmonary contusion
• pneumonia
• pulmonary fibrosis

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[DDET A-Profile]

Bilateral A-lines with lung sliding.

 

The presence of A-profile in a shocked patient = a FALLS responder. This suggests a hypovolaemic or distributive contributor to shock & correlates with pulmonary artery occlusion pressures of < 18mmHg [Sp 93%, PPV 97%].

The protocol recommends further fluid boluses with serial assessment by lung-ultrasound, looking specifically for change from A-lines to B-lines. At this stage, vasopressors would be started.

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[DDET The slideshow…]

[slideshare id=34888257&doc=ultrasoundupdatesforhems-140520012035-phpapp02]

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[DDET References.]

FALLS protocol + lung ultrasound

• Lichtenstein, D. A., & Mezière, G. A. (2008). Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest, 134(1), 117–125. doi:10.1378/chest.07-2800
• Lichtenstein, D. (2013). FALLS-protocol: lung ultrasound in hemodynamic assessment of shock. Heart, lung and vessels, 5(3), 142–147.
• Lichtenstein, D. A. (2014). Lung ultrasound in the critically ill. Annals of intensive care, 4(1), 1. doi:10.1186/2110-5820-4-1
• Mount Sinai Emergency Medicine Ultrasound.
  • The FALLS-protocol.

RUSH protocol.

• Perera, P., Mailhot, T., Riley, D., & Mandavia, D. (2010). The RUSH exam: Rapid Ultrasound in SHock in the evaluation of the critically lll. Emergency medicine clinics of North America, 28(1), 29–56– vii. doi:10.1016/j.emc.2009.09.010
• Seif, D., Perera, P., Mailhot, T., Riley, D., & Mandavia, D. (2012). Bedside Ultrasound in Resuscitation and the Rapid Ultrasound in Shock Protocol. Critical Care Research and Practice, 2012(3), 1–14. doi:10.1097/01.CCM.0000260680.16213.26
• Ultrasound Podcast.
  • It’s time to earn your vaginal stripes!
  • Castlefest 2014 and RUSH Podcast with Weingart.
  • RUSH Part 2 with Scott Weingart.
• EMCRIT.
  • Rapid Ultrasound for Shock and Hypotension – the RUSH Exam
• Mount Sinai Emergency Medicine Ultrasound.
  • RUSH.
• Academic Life in Emergency Medicine.
  • RUSH protocol: Rapid Ultrasound for Shock and Hypotension.

ECHO for Pulmonary Embolism.

• MD, S. D., et al. (2014). Right Ventricular Dilatation on Bedside Echocardiography Performed by Emergency Physicians Aids in the Diagnosis of Pulmonary Embolism. Annals of Emergency Medicine, 63(1), 16–24. doi:10.1016/j.annemergmed.2013.08.016
• Rudski, L. G.., et al. (2010). Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography, 23(7), 685–713– quiz 786–8. doi:10.1016/j.echo.2010.05.010
• Meyer, G., Vicaut, E., Danays, T., Agnelli, G., Becattini, C., Beyer-Westendorf, J., et al. (2014). Fibrinolysis for Patients with Intermediate-Risk Pulmonary Embolism. The New England journal of medicine, 370(15), 1402–1411. doi:10.1056/NEJMoa1302097
• Sosland, R. P., & Gupta, K. (2008). Images in cardiovascular medicine: McConnell’s Sign. Circulation, 118(15), e517–8. doi:10.1161/CIRCULATIONAHA.107.746602
• REBEL EM.
  • Diagnosis of Right Ventricular Strain with Transthoracic Echocardiography.

 

For a great bibliography on the evidence available for prehospital ultrasound, check out Cliff’s Resus.me.

Special thanks to Dr Justin Bowra for his assistance & advice with putting this together.

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