POCUS masterclass · Shock

Shock and clinical integration.

Pump, tank, pipes. Five windows, one question: why is this patient hypotensive?

Rapid Ultrasound in SHock (RUSH) is a structured bedside scan for the hypotensive patient whose cause is not yet clear. It joins the focused cardiac, IVC, eFAST, aortic and lung scans into one sequence, so you can answer three physiological questions in a few minutes:

  • Pump: is the heart the problem (tamponade, poor LV, failing RV)?
  • Tank: is the circulation empty, leaking or overloaded (IVC, free fluid, pleural fluid, B-lines, pneumothorax)?
  • Pipes: is a great vessel ruptured or blocked (aortic aneurysm or dissection, DVT as a marker of PE)?

For anaesthesia residents, MOs and ICU trainees who can already get the basic cardiac and lung views. The focus is on putting the views together and deciding what to do.

  • 01–02 · Why scan · the framework
  • Part I · Acquisition · the five windows
  • Part II · Interpretation · classifier
  • Part III · Arrest and peri-arrest · SESAME, pulse check
  • Part IV · Four patients in shock
  • Clinical decision cases · reporting
  • Quick check · Close
Review cardiac ultrasound →Review lung ultrasound →Review flow and fluids →
Schematic · subxiphoid 4-chamber
Schematic · IVC long axis
Animations are schematic teaching models. The separately labelled free-fluid video is a real ultrasound clip with its source and licence.
01 · Why scan in shock

The examination is unreliable. The scan narrows the list.

Undifferentiated shock (for example SBP < 90 mmHg or MAP < 65 mmHg with signs of hypoperfusion, such as raised lactate, oliguria or confusion) has four mechanisms that need opposite treatments.

The problem

Fluid helps hypovolaemia and may harm cardiogenic shock. Inotropes do nothing for tamponade. Decompression (needle or finger thoracostomy, then a chest drain) treats tension pneumothorax and helps nothing else.

Take-home: RUSH is a diagnostic tool. It helps only when it changes what you do, and only if you act on what it shows.
Diagnosis

In ED patients with non-traumatic hypotension, an immediate goal-directed scan narrowed the differential and made the correct final diagnosis more likely to be top of the list than a delayed scan (Jones 2004). Bedside ultrasound reduced diagnostic uncertainty and changed resuscitation decisions (Shokoohi 2015).

Accuracy

A 2023 meta-analysis (Yoshida, 12 studies, 1,132 patients) found POCUS has moderate-to-high sensitivity and high specificity for all four shock types. A positive pattern is good at ruling a cause in. A negative scan is weaker at ruling one out. An earlier RUSH-specific review reached the same conclusion (Stickles 2019); there, rule-out performance was best for obstructive shock (negative likelihood ratio about 0.13) and weakest for mixed shock.

Outcome

The SHoC-ED randomised trial (Atkinson 2018) found no survival benefit from a standard POCUS protocol in ED patients with undifferentiated hypotension. It also found no harm.

02 · The framework

Pump. Tank. Pipes. In the HI-MAP order.

Perera's three questions (2010)
ComponentQuestionMain views
PumpEffusion or tamponade? LV squeezing? RV dilated?Subxiphoid, PLAX, PSAX, A4C
TankHow full is it? Is it leaking? Is it overloaded?IVC, eFAST (Morison's, splenorenal, pelvis), pleural bases, anterior lung
PipesIs the aorta ruptured or dissected? Is there clot in the leg veins?Abdominal aorta (subxiphoid to bifurcation), aortic root in PLAX, 2-point leg compression
Before you start, answer four questions
  1. What is my clinical shortlist?
  2. Which views will separate those causes?
  3. What will I do differently for each result?
  4. When will I scan again?
HI-MAP: the scanning order

HI-MAP is the EMCrit (Weingart) version, 'Rapid Ultrasound for Shock and Hypotension'. Pump/Tank/Pipes is Perera 2010, 'Rapid Ultrasound in SHock'. They are two related protocols covering the same views.

  • H
    HeartSubxiphoid first, then parasternal and apical views.
  • I
    IVCSubxiphoid long axis, measured about 1–2 cm from the RA junction.
  • M
    Morison'sThe eFAST abdominal views, including the bases for pleural fluid.
  • A
    AortaTransverse, from the subxiphoid region to the bifurcation.
  • P
    PneumothoraxAnterior lung sliding on both sides, with B-lines during the same sweep.

Add legs (2-point compression at the common femoral and popliteal veins) when the RV is dilated or PE is suspected.

Prioritise the window most likely to change urgent treatment. Act on time-critical findings immediately, then complete or repeat the relevant survey as resuscitation allows; more than one mechanism may coexist.
Part I · Acquisition

Five windows.

Phased array (cardiac) for the heart, IVC, aorta and lungs; the curvilinear probe as an alternative for the abdomen and aorta. Linear probe for pleural detail and the DVT scan. Patient supine.

Get the views · then decide what they mean

Schematic torso. HI-MAP probe positions, plus the legs for 2-point compression.
03 · The HI-MAP tour

Where the probe goes, and what normal and abnormal look like.

Select each probe station (click, or Tab and Enter). Each opens a schematic sonogram with a Normal / Abnormal toggle and a link to the detailed page.

Dot = probe marker. H and I: cardiac preset, marker to the patient's left (H) or head (I), screen marker on the right. M and P: marker to the head. A and legs: transverse, marker to the patient's right (abdominal preset, screen marker on the left). The blue dot on each sonogram shows the screen marker.
H · Subxiphoid 4-chamber
Detail →
Schematic teaching simulation, not a real scan.
04 · Pump

Three questions of the heart, not a full echo.

The focused cardiac scan answers yes/no questions (FoCUS: Spencer 2013; WINFOCUS international recommendations, Via 2014). Full detail is on the Cardiac page.

1 · Is there a pericardial effusion, and is it causing tamponade?
  • Effusion: an anechoic space between the pericardium and the heart. In PLAX, a pericardial effusion runs in front of the descending thoracic aorta. A pleural effusion runs behind it.
  • Tamponade signs: RA collapse in systole (sensitive, appears early), RV free-wall collapse in early diastole (more specific), and a plethoric IVC with little respiratory variation (sensitive, not specific).
  • Tamponade is a clinical-plus-echo diagnosis. A small effusion in a shocked patient may be incidental. A fast-collecting small effusion (after trauma, cardiac surgery or a procedure) can tamponade.
  • Pitfall: an epicardial fat pad (seen at the front only, speckled, moves with the heart) is not an effusion.
2 · How is the LV squeezing?

Start with a multi-view visual assessment: hyperdynamic (walls nearly meet at end-systole) / normal / reduced / severely reduced. Trained emergency and critical care clinicians agree well with formal echo on this. Hyperdynamic with a small cavity fits hypovolaemia, early distributive shock, or an under-filled LV behind an RV obstruction.

Schematic teaching simulation, not a real scan.
3 · Is the RV dilated?
  • Bedside heuristic: in A4C the RV is normally about two-thirds of LV size, and RV ≥ LV means it is significantly dilated. Formal ASE cut-offs (Lang 2015; ASE right heart guideline 2025): RV basal diameter ≥ 41 mm is above the 2025 normal range; TAPSE ≤ 17 mm is outside its normal range. Neither measurement alone defines RV failure. Avoid a foreshortened or off-axis A4C, which falsely enlarges the RV. In PSAX, a D-shaped LV shows septal flattening from RV pressure or volume overload.
  • In shock, RV dilatation with a small LV requires urgent assessment for RV pressure loading or failure. Causes include PE, acute cor pulmonale, ventilatory effects and RV infarction. Compare prior imaging and the clinical context. A thick RV wall supports chronic loading; a thin wall does not establish an acute cause or diagnose PE.
  • McConnell's sign (RV free wall moving poorly while the apex still contracts) suggests acute PE but is not sensitive, and is also seen in RV infarction. Use it as supportive, not diagnostic.

Also look for: a dilated aortic root (> 4 cm in PLAX) or an intimal flap (dissection), and gross valve failure (flail leaflet, torrential regurgitation). Both need formal echo. A small, hyperdynamic LV on inotropes can cause dynamic LV outflow tract obstruction (systolic anterior motion of the mitral valve): confirm the mechanism with expert echo and Doppler. Additional inotropy can worsen obstruction. Adjust inotropes, vascular tone and preload to the confirmed physiology; fluid requires a perfusion indication and assessment of congestion.

05 · Tank (I): the IVC

A pressure gauge, not a fluid-responsiveness test.

Subxiphoid long axis. Show the IVC entering the RA; measure about 1–2 cm caudal to the RA junction (just caudal to where the hepatic vein joins), at right angles to the vessel walls. M-mode helps.

Spontaneous breathing: estimating RAP (ASE: Rudski 2010, Lang 2015)
IVC diameterCollapse with sniffEstimated RAP
≤ 2.1 cm> 50%3 mmHg (0 to 5)
> 2.1 cm< 50%15 mmHg (10 to 20)
Any other combination8 mmHg (5 to 10)
How to read it
  • A small, collapsing IVC in a shocked patient suggests low RAP. This can fit hypovolaemic or distributive physiology, but does not establish a fluid indication, responsiveness or tolerance.
  • A plethoric, fixed IVC suggests high RAP: tamponade, PE, tension pneumothorax, RV failure, or fluid overload. It does not by itself establish whether stroke volume will increase with fluid. Consider congestion, the cause of raised RAP and a valid dynamic flow test.
  • Not a reliable predictor of fluid responsiveness in the spontaneously breathing patient. The middle range tells you little.
  • On positive-pressure ventilation the pattern reverses: the IVC distends on inspiration. A distensibility index > 18% predicted fluid responsiveness in Barbier 2004 (sedated, passively ventilated septic patients, tidal volume about 8.5 mL/kg). Performance is poor at lung-protective tidal volumes (6 mL/kg), with spontaneous breathing effort, or with raised intra-abdominal pressure. A dilated IVC on the ventilator is common and less meaningful; a small IVC is still informative.

Pitfalls: the cylinder effect (scanning off-centre underestimates the diameter); the aorta mistaken for the IVC; raised intra-abdominal pressure; severe TR; athletes with large IVCs; a forceful sniff exaggerating collapse. If the subxiphoid window is poor, the internal jugular vein (Perera's original RUSH 'Tank') is an alternative gauge of venous pressure. Explore flow and fluid assessment →.

Schematic teaching simulation, not a real scan. Diameters and collapse values are illustrative, chosen to fall in the ASE categories.
06 · Tank (II): leaks and overload

Free fluid, pleural fluid, B-lines, pneumothorax.

Leaking tank: free fluid (eFAST views)

Morison's pouch (the most dependent upper-abdominal space when supine, and the most sensitive single view), the splenorenal and subphrenic spaces, and the pelvis. See eFAST.

  • In trauma, free fluid plus shock means haemorrhage until proven otherwise.
  • In non-trauma, think about ruptured ectopic pregnancy (any woman of reproductive age), ascites (chronic, and may be the sepsis source: spontaneous bacterial peritonitis), or ruptured viscus.
  • A negative FAST does not exclude bleeding: small volumes, retroperitoneal bleeding (pelvic fracture, AAA) and early scans can all be missed. Repeat the scan.
Pleural spaces

At the bases, look for the spine sign (vertebral bodies seen above the diaphragm through fluid) and an anechoic collection above the diaphragm: haemothorax, heart failure, empyema.

Overloaded tank: B-lines (Volpicelli 2012)
  • ≥ 3 B-lines in an intercostal space = a positive region. Bilateral, diffuse positive regions = interstitial syndrome. With poor LV contraction and raised right-sided pressure, this can support a cardiogenic congestion component, but does not exclude mixed or non-cardiogenic disease.
  • B-lines are not specific: ARDS, pneumonia and fibrosis also cause them. Patchy distribution, pleural-line irregularity and spared areas point to non-cardiogenic causes. Detail on the Lung page.
  • New B-lines appearing during fluid resuscitation are a reason to pause and reassess tolerance (the FALLS-protocol idea, Lichtenstein).
Schematic teaching simulation, not a real scan.

A real scan: free fluid

Free fluid beside the liver and kidney in a published trauma example. Ultrasound identifies fluid, not its composition. A negative FAST does not exclude bleeding or retroperitoneal injury.

Gillman et al., 2009, supplementary clip 1 · Source · CC BY 2.0. Transcoded and display proportions normalised; audio removed. Browse the real-scan library →

Pneumothorax (the P in HI-MAP): least dependent anterior chest
  • Lung sliding, B-lines or a lung pulse at the probe = no pneumothorax at that point (high negative predictive value).
  • No sliding is not specific: mainstem intubation, apnoea, pleurodesis, adhesions, bullae, ARDS.
  • A true lung point supports pneumothorax. Bullae and other interfaces can mimic it; recognise the transition, check adjacent areas and interpret the clinical context.
  • Tension pneumothorax is a clinical diagnosis. When clinical tension is strongly suspected (haemodynamic collapse with unilateral chest findings, hypoxia or rising airway pressures), decompress immediately; an IVC or lung sign is not a prerequisite. Do not hunt for a lung point first. If time allows, check the tube position and look for a lung pulse.
07 · Pipes

Scan the whole aorta. Measure outer wall to outer wall.

Abdominal aorta screen
  • Curvilinear or phased-array probe, transverse, epigastric midline. The aorta sits just anterior and slightly left of the vertebral body (bright curve with a shadow below). The IVC is on the patient's right.
  • Sweep in steps: coeliac trunk (the 'seagull') → SMA → renal level (left renal vein crosses between aorta and SMA) → infrarenal aorta → bifurcation (just above the umbilicus, about L4). Most AAAs are infrarenal, so stopping early misses them.
  • Measure the maximum anteroposterior diameter, outer wall to outer wall, at right angles to the long axis. Confirm in long axis. Screening programmes may use inner-to-inner (UK NAAASP), so state the method in your report.
  • ≥ 3.0 cm = aneurysm. Mural thrombus can make the lumen look normal. Measure the wall, not the flow channel.
  • Gas: steady graded pressure, move left or right, or use a coronal view through the liver or flank.
What the scan can and cannot tell you
  • ED bedside ultrasound is highly accurate at finding an AAA (Rubano 2013).
  • It cannot reliably show rupture. Most ruptures bleed into the retroperitoneum, so there is often no intraperitoneal free fluid.
  • Hypotension + known or newly found AAA = ruptured AAA until proven otherwise. Activate the vascular team immediately. Prompt CTA is usually needed for repair planning when feasible; profound instability may require direct operative management.
Other pipes
  • Dissection: a dilated aortic root in PLAX, an intimal flap, new aortic regurgitation or a pericardial effusion are clues. TTE cannot exclude dissection. Get CT or TOE.
  • DVT: 2-point compression of the common femoral vein (at and just distal to the saphenofemoral junction) and the popliteal vein. A non-compressible vein in a shocked patient with a dilated RV strongly supports PE. See DVT.
Schematic teaching simulation, not a real scan. Radiology convention: patient's left on screen right. Draw calipers: turn on, then drag across the vessel.
Part II · Interpretation

Put the views together.

Integrate patterns with the clinical picture and repeat the assessment after intervention. Mixed disease and acquisition error can still mislead.

Shock is often mixed

Mixed shock is common
  • A septic patient with septic cardiomyopathy.
  • A bleeding patient on a beta-blocker.
  • A PE patient who is also dry.
08 · Findings by shock type

The RUSH table.

Adapted from Perera 2010 (RUSH findings in classic shock states).

HypovolaemicCardiogenicObstructiveDistributive
PumpHyperdynamic, small LV cavityPoorly contracting, often dilated LVHyperdynamic LV; effusion with RA/RV collapse (tamponade); dilated RV (PE); mediastinal shift (tension PTX)Hyperdynamic early; may be reduced in septic cardiomyopathy
Tank: IVCSmall, collapsingPlethoricPlethoricNormal or small (early)
Tank: lungs and spacesFree fluid (haemorrhage); haemothoraxBilateral B-lines; pleural effusionsAbsent sliding + lung point (pneumothorax); A-lines with PEFree fluid or effusion as the source (peritonitis, empyema); focal consolidation
PipesAAA, dissectionUsually normalDVT (supports PE)Usually normal
How to use the table
  • Hypovolaemic and early distributive shock look the same on ultrasound (hyperdynamic LV, small IVC). Tell them apart clinically: warm vs cold peripheries, fever, source, bleeding history.
  • Obstructive shock: a plethoric IVC with a small, hyperdynamic LV (underfilled behind the obstruction). The cause is the effusion, the RV or the pleura.
 
  • Cardiogenic shock: poor LV + plethoric IVC + B-lines. Look for a mechanical cause (acute MR, VSD, severe AS) on formal echo.
  • A-lines everywhere + shock makes cardiogenic pulmonary oedema unlikely (BLUE-protocol logic, Lichtenstein 2008). Add a DVT scan: A-profile + proximal DVT strongly suggests PE (BLUE protocol, derived in acute respiratory failure rather than shock: specificity about 99%, sensitivity about 81%). A negative leg scan does not exclude PE.
09 · Compare shock patterns

Toggle the findings. Watch the pattern change.

Select only findings you have assessed. Compare mechanisms, the observations supporting each and what remains uncertain. More than one mechanism can coexist; these patterns do not provide a diagnosis or probability.

Pattern supported
Caveats

    No score or validated diagnostic rule. Unassessed findings stay unknown.

    10 · Integrate, act, repeat

    The scan is a snapshot. Shock is a film.

    Integrate with the clinical picture
    • Start from the history, examination, ECG, lactate and blood gas. Ultrasound adjusts your probabilities. It does not replace them.
    • Rule in rather than rule out. Specific findings can narrow the differential, but an effusion is not automatically tamponade, an AAA is not proof of rupture, and B-lines do not establish cardiogenic oedema. A normal-looking scan does not exclude PE, dissection, a contained bleed or sepsis.
    • Name a leading diagnosis and an action after every scan: fluid, vasopressor, inotrope, drain, decompress, thrombolyse, call the surgeon.
    Serial scanning
    • Rescan after each intervention: after a 250 to 500 mL fluid bolus, after starting a vasopressor, and after any deterioration.
    • Look for: LV filling, change in IVC size, new B-lines (pause and reassess fluid tolerance), an enlarging effusion, new free fluid, and septic cardiomyopathy unmasked once vasopressors raise afterload.
    • Record each scan: views obtained, findings, image quality, time. An inadequate view is not a normal view.
    Limitations
    • Depends on the operator and on body habitus. Ventilated, obese, post-operative and surgical-emphysema patients give poor windows.
    • Static measures (IVC) predict fluid responsiveness poorly. Use dynamic tests (passive leg raise with LVOT VTI or cardiac output) when the question matters. See Haemodynamics.
    • No outcome benefit has been shown in an RCT (SHoC-ED). A faster diagnosis matters only when it leads to an appropriate change in management.
    • Ultrasound cannot exclude: aortic dissection, retroperitoneal bleeding, early or small free fluid, or PE without RV strain.
    • Do not let scanning delay life-saving treatment (CPR, indicated defibrillation, decompression for clinical tension pneumothorax, blood or surgical escalation).
    After every scan, say out loud: leading diagnosis, action, and when you will scan again.
    Part III · Arrest and peri-arrest

    When the pulse goes.

    The same windows, a different clock. In arrest, ultrasound has to fit inside the ALS loop: scan what you can during compressions, and give the heart no more than the pulse-check pause.

    SESAME · the 10-second pulse check · pitfalls and guidance

    Compressions · 2 min ≤10 s CPR Lung · veins · abdomen (second operator) Probe on subxiphoid, view found Record a clip Review the clip while CPR continues
    Schematic of one ALS cycle. Timings are the usual 2-minute cycle and the conventional 10-second pulse-check limit.
    11 · SESAME

    SESAME: lung first, heart last.

    Lichtenstein's Sequential Echographic Scanning Assessing Mechanism Or Origin of Severe Shock of Indistinct Cause is a whole-body scan for cardiac arrest and severe shock. He does it with one microconvex probe, so no time is lost changing probes.

    StepLooks forIf positive
    1 · LungPneumothorax: assess sliding, B-lines and lung pulse. A lung point can support the diagnosis.Decompress clinical tension immediately; do not wait for a lung point
    2 · VeinsLower-limb DVT, the clue to PESupports PE in context; urgent senior-led reperfusion assessment, not automatic thrombolysis
    3 · AbdomenMassive haemorrhage. In trauma, do this before the veins.Blood, surgeon
    4 · PericardiumEffusion and tamponadeDrain
    5 · HeartOther cardiac causes, and whether there is any activityDepends on the finding
    The logic

    Start with the cause that is quickest to rule in and quickest to fix (pneumothorax). The lung, legs and abdomen can be scanned while compressions continue, by a second operator. The heart, which RUSH looks at first, comes last here: during CPR you can only see it clearly in the pulse-check pause. CASA uses the same split: lung and free fluid during compressions, the heart during pulse checks (Gardner 2018).

    SESAME is an expert protocol (Lichtenstein 2014; Lichtenstein and Malbrain 2015). It has not been tested for its effect on survival.

      1 · Lung
      Detail →
      Schematic teaching simulation, not a real scan.
      12 · Ultrasound in the ALS loop

      Scan in the pause. Read it during compressions.

      Before the pause
      • The person scanning is not the team leader. In one ED study, pauses were longer when the doctor leading the resuscitation also did the scan (Clattenburg 2018).
      • Put the probe on the subxiphoid window during compressions and find the view. It usually stays clear of the hands and pads; if it interferes with compressions, lift off and reapply just before the pause. Keep the probe in place for the pause (CASA).
      During the pause: 10 seconds at most
      • Someone counts the seconds out loud. The pulse check, rhythm check and scan share the same pause, which should not last longer than 10 s.
      • Record a clip; do not try to interpret it live. If you have no view by 10 s, restart compressions and try again at the next check.
      After compressions restart
      • Review the clip and report one question per pulse check (CASA, Gardner 2018): 1 · tamponade? 2 · RV dilated? 3 · any cardiac activity?
      • Say the finding to the team leader, who decides what to do.
      Pulse-check simulator · subxiphoid clip
      CPR
      Teaching simulation. The countdown runs in real time. Images are schematic, not real scans.
      13 · Pitfalls, evidence and guidance

      A good finding helps you act. One finding alone should not stop resuscitation.

      Pauses get longer

      Video studies in the ED found longer pauses when ultrasound was used (Huis in 't Veld 2017; Clattenburg 2018). Scan to a count, record a clip, and review it later.

      Standstill is not a reason to stop on its own

      Standstill is strongly linked to death (0.6% survived to discharge in REASON), but not 0%. Observers disagree on what counts as activity, and studies define it differently. The decision to stop belongs to the team and rests on the whole picture.

      People disagree on "activity"

      Physician sonographers rating the same arrest clips reached only moderate agreement on standstill (Hu 2018: 127 physicians, 15 clips, α 0.47). Clips with valve flutter, or with motion from compressions or ventilation, are commonly misread; none of these counts as cardiac activity.

      Pseudo-PEA

      Organised wall motion with no palpable pulse is common in patients thought to be in PEA (Breitkreutz 2010). Continue ALS and compressions per protocol unless an arterial line shows an adequate pressure. Meanwhile look hard for a reversible cause and consider vasopressor support.

      A dilated RV does not prove PE

      The RV can dilate during arrest from non-PE causes: in pigs it dilated after hypovolaemic, hyperkalaemic and primary arrhythmic arrest (Aagaard 2017). ERC guidance advises against diagnosing PE from RV dilation on its own during arrest. Look for support: the story, a DVT, an early scan.

      Fine VF or asystole?

      Fine VF can look like asystole on the monitor. Ultrasound may show a quivering, uncoordinated myocardium. In one ED TOE study, TOE identified VF in some out-of-hospital arrests thought to be asystole (Teran 2019). Check the leads and the gain, and say what you see to the team leader.

      TOE where available

      After intubation, TOE gives continuous views during compressions without needing a pause. It also shows where compressions land, which in Teran 2019 was over the aortic root or LVOT in 53% of patients rather than over the LV. It needs a trained operator. ILCOR's scoping review of TOE summarised the evidence without a treatment recommendation.

      Cardiac: the subxiphoid viewLung: sliding and the lung pointDVT: 2-point compression
      Part IV · Cases

      Four patients in shock.

      Read the vignette, commit to a shock type and a first action, then reveal one step at a time (R). Cases 1 to 3 follow HI-MAP; case 4 is an arrest, scanned in the SESAME order.

      Teaching vignettes. All images are schematic simulations. Each case can be loaded into the classifier.

      Clinical integration

      Eight decisions beyond the first image.

      Constructed cases. Describe the observation, test the inference and choose the next step.

      Cases 1, 2, 4 and 5 also have real-clip versions: work them in Case studies →

      Case 1 · The vanishing IVC

      A patient’s IVC seems to collapse completely with each inspiration. During scanning, the vessel also moves sideways out of the imaging plane. A junior recommends a fluid bolus.

      Is the observation reliable? What does a respiratory IVC change actually establish?

      Compare your reasoning

      First correct the acquisition. Track the vessel through respiration and confirm its connection to the right atrium. Out-of-plane motion can mimic collapse. Even a technically valid change is affected by respiratory effort, ventilation and right-heart physiology. Establish the perfusion problem, then select a valid dynamic test and assess congestion.

      Verify acquisition before interpreting physiology.

      Review the underlying physiology →

      Schematic comparison

      Illustrative anatomy and numbers. These are constructed teaching diagrams, not patient scans or a diagnostic model.

      Supervised practice

      Make the reasoning reviewable.

      A focused report

      Question
      Indication, relevant background and what the scan could change.
      Conditions
      Position, rhythm and heart rate, BP, ventilation/PEEP and cardiovascular support.
      Quality and scope
      Views obtained; adequate, limited or non-diagnostic for this question.
      Findings
      LV, RV, pericardium, relevant flow measurements, lungs and pleura. Include method and units.
      Interpretation
      What the observations support in this clinical context; alternative explanations.
      Limits
      Structures not seen, unreliable measurements and diagnoses not excluded.
      Action
      Treatment, escalation, formal imaging and reassessment plan.
      Record
      Operator, date/time, supervisor or reviewer and saved image location.

      A 30-minute teaching session

      1. 0–3 min: agree one clinical question.
      2. 3–15 min: acquire purposeful views; correct one technical problem.
      3. 15–22 min: describe findings and repeat a measurement when appropriate.
      4. 22–27 min: test an alternative explanation.
      5. 27–30 min: save clips, report the limits and agree one practice goal.

      Feedback that changes the next scan

      Assess preparation, acquisition, interpretation, integration and documentation through supervised image review. Scan count alone does not establish competence.

      Use specific feedback: “The apex is rounded; move laterally and maximise LV length before tracing.” Ask for one technical and one physiological alternative to the interpretation.

      Store patient data in approved systems. Teaching images must be authorised and de-identified.

      “Limited study” is a finding about image quality. It must not become “normal study” in the handover.
      Quick check

      Ten questions before we finish.

      Tamponade signs, the IVC, aorta measurement, pneumothorax, the PE pattern, the evidence, and ultrasound during cardiac arrest. One at a time.

      Scan, act, rescan

      Scan, act, reassess.

      Four things to take away
      1. Use pump, tank and pipes to organise the scan. Treat immediately reversible threats first; complete the relevant survey when resuscitation permits.
      2. A coherent pattern narrows the differential. A normal-looking or incomplete scan does not exclude all important disease.
      3. Rescan after every intervention.
      4. In arrest: scan during compressions, record within a 10-second pause, and never stop CPR on one ultrasound finding.
      Go deeper
      Focused cardiac ultrasoundLung ultrasoundeFASTDVT and vesselsGastric ultrasoundUS-guided vascular access

      Simulations are purpose-built teaching models, not diagnostic images. Anatomy, echogenicity and thresholds are simplified. Contact: contact@anantf.com

      Schematic · anterior chest
      Schematic · aorta, transverse
      Key references

      Where the numbers come from.

      Key references (tap to collapse)
      1. Monnet X, Messina A, Greco M, et al. ESICM guidelines on circulatory shock and haemodynamic monitoring 2025. Intensive Care Med. Read the guideline →
      2. Monnet X, Teboul JL. Passive leg raising: five rules, not a drop of fluid! Crit Care. 2015;19:18. Read PLR methodology →
      3. Demi L, Wolfram F, Klersy C, et al. New international guidelines and consensus on the use of lung ultrasound. J Ultrasound Med. 2023;42:309–344. Read the lung consensus →
      4. Perera P, Mailhot T, Riley D, Mandavia D. The RUSH exam: Rapid Ultrasound in SHock in the evaluation of the critically ill. Emerg Med Clin North Am. 2010;28(1):29–56. doi:10.1016/j.emc.2009.09.010
      5. Weingart SD, Duque D, Nelson B. Rapid Ultrasound for Shock and Hypotension (RUSH-HIMAPP). EMCrit [online]. 2009. Source
      6. Jones AE, Tayal VS, Sullivan DM, Kline JA. Randomized, controlled trial of immediate versus delayed goal-directed ultrasound to identify the cause of nontraumatic hypotension in emergency department patients. Crit Care Med. 2004;32(8):1703–8. PubMed
      7. Shokoohi H, Boniface KS, Pourmand A, et al. Bedside ultrasound reduces diagnostic uncertainty and guides resuscitation in patients with undifferentiated hypotension. Crit Care Med. 2015;43(12):2562–9. doi:10.1097/CCM.0000000000001285
      8. Atkinson PR, Milne J, Diegelmann L, et al. Does point-of-care ultrasonography improve clinical outcomes in emergency department patients with undifferentiated hypotension? An international randomized controlled trial from the SHoC-ED investigators. Ann Emerg Med. 2018;72(4):478–89. doi:10.1016/j.annemergmed.2018.04.002
      9. Stickles SP, Carpenter CR, Gekle R, et al. The diagnostic accuracy of a point-of-care ultrasound protocol for shock etiology: a systematic review and meta-analysis. CJEM. 2019;21(3):406–17. doi:10.1017/cem.2018.498
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      The eight clinical decision cases are constructed from SCCM Critical Care Ultrasound: Adult teaching themes. They are not real patients.

      Simulations are purpose-built schematic teaching models, not diagnostic images. Anatomy, echogenicity, timing and thresholds are simplified. Check thresholds against current guidelines and local protocols.