Ultrasound: In Shock and Hypotension
Background
- A bedside ultrasound paradigm for differentiating differentiating shock states (cardiogenic, obstructive, hypovolemic, distributive)
- Tailor specific protocol to the patient at hand
- RUSH Protocol was conceived in 2008 and looks are 3 basic aspects of physiology[1][2]
- The Pump
- RV:LV
- Squeeze
- Pericardial effusion and tamponade
- The Tank
- The Pipes
The Protocol
Rapid Ultrasound for Shock and Hypotension(RUSH) using the HI-MAP approach[3]
- H - Heart (parasternal and four-chamber views)
- I - Inferior Vena Cava (for volume responsiveness)
- M - Morison’s pouch (i.e., FAST exam) and views of thorax (looking for free fluid)
- A - Aortic Aneurysm (ruptured abdominal aneurysm)
- P - Pneumothorax (i.e., Tension pneumothorax)
Heart
Technique: see Cardiac ultrasound
- Pericardial Effusion
- May be most obvious with PLAX or subxiphoid views[4]
- In PLAX, pericardial fluid is anterior to descending aorta, while pleural fluid is posterior to it
- Isolated anterior anechoic areas may be an anterior fat pad
- Assess for tamponade physiology including diastolic collapse of RA or RV; see Pericardial effusion and tamponade
- May be most obvious with PLAX or subxiphoid views[4]
- LV squeeze
- PLAX and PSAX are good views to estimate contractility
- Change in size <30% between sys and dia = poor LV function
- Hyperdynamicity, as determined by walls moving >90% or touching at end of systole, may indicate hypovolemia or sepsis
- May direct fluid therapy
- RV strain
- In 4-chamber view, RV should be <60% of LV; if dilated/larger think RV strain
- While chronic RV strain (ex. cor pulmonale) may cause RVH, massive PE will not have time to cause RVH
IVC
Technique: see IVC ultrasound
- Measure 2cm caudally from RA-IVC junction
- If IVC <2.1cm and collapses >50% on inspiration then RAP/CVP is low[5]
- If IVC >2.1cm and collapses <50% then RAP/CVP is high
- Suggests fluid unresponsive; patient requires inotropes
- IVC measurements may be altered in patients receiving vasoactive medications or positive pressure ventilation
Morison's
Technique: see FAST exam
- Assess for free fluid
- Morison's pouch (hepatorenal space)
- Splenorenal
- Bladder, including retrovesicular space
- As part of E-FAST, when in hepatorenal or splenorenal views, aim/slide probe above diaphragm to assess for pleural effusion
- Note that while ascitic fluid often appears anechoic, blood may appear with mixed echogenicity due to the presence of clots
Aorta
Technique: see Aortic ultrasound
- Steady pressure with probe can displace bowel gas, improving view
- If >5cm assume ruptured AAA until proven otherwise
- In PLAX, aortic root >3.8cm may be seen in proximal aortic dissection or aortic aneurysm[6]
Pulmonary
Technique: see Ultrasound: Lungs
- Assess for subpleural interstitial edema
- Look for multiple comet tail artifacts or "B lines"(a few, 3-4, are OK)
- If multiple found, there is interstitial pulmonary edema
- Look for multiple comet tail artifacts or "B lines"(a few, 3-4, are OK)
- Assess for pneumothorax
- Scan longitudinally in anterior 2nd-3rd IC space, mid-clavicular line, looking for echogenic pleural line
- On M-mode, look for lack of pleural sliding, aka "Barcode sign"
- Presence of lung point is highly specific for PTX
Other
Classic Ultrasound Findings For Critically Ill Patients
Disease | IVC | Cardiac | Lung (Phased Array) | Lung (Linear) |
---|---|---|---|---|
MI | ↑ | Focal WMA Mod/Poor squeeze |
NL or B-lines | Sliding |
Tamponade | ↑ | RA collapse with filling RV collapse with filling |
NL | Sliding |
PTX | ↑ | NL or Hyperdynamic | Lung point Consolidated lung |
Absent lung sliding |
Sepsis | ↓ | Hyperdynamic squeeze | NL (see pneumonia) | Sliding |
Pneumonia | NL or ↓ | Hyperdynamic squeeze | Unilateral B-lines | Sliding |
Decompensated HF | ↑ | Mod/Poor squeeze | Bilateral B-lines | Sliding |
PE | ↑ | RV > LV McConnell's sign |
NL or Unilateral B-lines | Sliding |
See Also
External Links
References
- ↑ Perera P, Mailhot T, Riley D, Mandavia D. The RUSH exam: Rapid Ultrasound in SHock in the evaluation of the critically lll. Emerg Med Clin North Am. 2010 Feb;28(1):29-56, vii. doi: 10.1016/j.emc.2009.09.010. PMID: 19945597.
- ↑ Weingart - https://emcrit.org/rush-exam/
- ↑ Dina Seif. Bedside Ultrasound in Resuscitation and the Rapid Ultrasound in Shock Protocol Critical Care Research and Practice Vol 2012 http://downloads.hindawi.com/journals/ccrp/2012/503254.pdf
- ↑ Alerhand S, Carter JM. What echocardiographic findings suggest a pericardial effusion is causing tamponade? Am J Emerg Med. 2019 Feb;37(2):321-326. doi: 10.1016/j.ajem.2018.11.004. Epub 2018 Nov 17. PMID: 30471929.
- ↑ Rudski LG, Lai WW, Afilalo J, Hua L, Handschumacher MD, Chandrasekaran K, Solomon SD, Louie EK, Schiller NB. 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. J Am Soc Echocardiogr. 2010 Jul;23(7):685-713; quiz 786-8. doi: 10.1016/j.echo.2010.05.010. PMID: 20620859.
- ↑ Seif D, Perera P, Mailhot T, Riley D, Mandavia D. Bedside ultrasound in resuscitation and the rapid ultrasound in shock protocol. Crit Care Res Pract. 2012;2012:503254. doi: 10.1155/2012/503254. Epub 2012 Oct 24. PMID: 23133747; PMCID: PMC3485910.