# Clinical Cases: Emergency Ultrasound

## Case 1: FAST Exam - The Hypotensive Trauma Patient

### Patient Demographics
- **Age:** 28 years
- **Sex:** Male
- **Occupation:** Construction worker

### Chief Complaint
"Car accident - he's really hurt."

### History of Present Illness
A 28-year-old male is brought by EMS after high-speed motor vehicle collision. He was the unrestrained driver when his vehicle struck a tree at approximately 50 mph. Airbags deployed. He was initially alert at scene but has become increasingly confused en route. EMS reports significant steering wheel deformity and dashboard intrusion.

### Initial Assessment (Trauma Activation)

**ESI Level:** 1 - Major trauma, hemodynamic instability

**First Impression:**
- Appearance: Pale, diaphoretic, confused
- Work of breathing: Tachypneic, clear bilateral breath sounds
- Circulation: Pale, tachycardic, delayed cap refill

**Vital Signs:**
- Heart rate: 132 bpm
- Blood pressure: 82/54 mmHg
- Respiratory rate: 28 breaths/min
- SpO2: 96% on NRB
- Temperature: 36.4C
- GCS: 12 (E3V4M5)

### Trauma Primary Survey

**A - Airway:** Patent, speaking in words
**B - Breathing:** Bilateral breath sounds, tachypneic
**C - Circulation:** Hypotensive, tachycardic, pale - **SHOCK**
**D - Disability:** GCS 12, moving all extremities, pupils equal
**E - Exposure:** Seatbelt sign across abdomen, no obvious external hemorrhage

### FAST Exam Indication

**Hypotensive trauma patient - need to identify source of bleeding**

**FAST = Focused Assessment with Sonography in Trauma**

**Goal:** Identify free fluid (blood) in:
1. Perihepatic space (Morison's pouch)
2. Perisplenic space
3. Pelvis
4. Pericardium

### FAST Exam Protocol

**Equipment:**
- Portable ultrasound machine
- Curvilinear (abdominal) probe (2-5 MHz)
- Phased array probe for cardiac view (optional)

**Patient Position:** Supine (trauma bay)

**Four Views of FAST:**

**1. Right Upper Quadrant (RUQ) - Morison's Pouch:**
- Probe: Curvilinear, 9-11 o'clock position
- Location: Right anterior axillary line, 9th-11th intercostal space
- Target: Hepatorenal space (most dependent space in supine patient)
- **FINDING: POSITIVE - Anechoic stripe (black) between liver and kidney**

**2. Left Upper Quadrant (LUQ) - Splenorenal Space:**
- Probe: More posterior than RUQ (spleen is more posterior)
- Location: Left posterior axillary line, 6th-9th intercostal space
- Target: Perisplenic space, splenorenal recess
- **FINDING: POSITIVE - Fluid around spleen and above diaphragm**

**3. Pelvis (Suprapubic):**
- Probe: Midline suprapubic, transverse and sagittal
- Target: Rectovesical pouch (males), pouch of Douglas (females)
- **FINDING: POSITIVE - Fluid posterior to bladder**

**4. Cardiac (Subxiphoid):**
- Probe: Subxiphoid, angled toward left shoulder
- Target: Pericardial effusion
- **FINDING: NEGATIVE - No pericardial fluid**

### FAST Results Summary

| View | Finding |
|------|---------|
| RUQ (Morison's) | POSITIVE - free fluid |
| LUQ (Splenorenal) | POSITIVE - free fluid |
| Pelvis | POSITIVE - free fluid |
| Cardiac | NEGATIVE |

**INTERPRETATION:** Significant hemoperitoneum - patient needs emergent laparotomy

### Clinical Decision-Making

**Hypotensive trauma + Positive FAST = OR for laparotomy**

**NO CT SCAN** - Patient too unstable; would delay definitive treatment

**Algorithm:**
```
Blunt Trauma + Hypotension
         ↓
    FAST Exam
         ↓
    POSITIVE → Operating Room (exploratory laparotomy)
         ↓
    NEGATIVE → Consider other sources (chest, pelvis, external)
                Consider repeat FAST or CT if stable
```

### Resuscitation While Preparing for OR

**Massive Transfusion Protocol Activated:**
- 4 units PRBC
- 2 units FFP
- 1 unit platelets
- TXA 1g IV (within 3 hours of injury)

**Access:**
- Two large-bore IVs (18g or larger)
- IO backup available

**Blood Pressure Response:**
- After 2 units PRBC: BP 94/62 (transient response = ongoing hemorrhage)

### Operative Findings

**Exploratory Laparotomy:**
- 2.5L hemoperitoneum
- Grade III splenic laceration with active hemorrhage
- Splenectomy performed
- Small mesenteric tear - repaired
- No other injuries

### Post-Operative Course
- ICU admission
- Additional transfusion: 2 units PRBC
- Hemodynamically stable post-op
- Transferred to floor day 2
- Vaccinations for asplenia (pneumococcal, meningococcal, H. flu)
- Discharged day 5

### Teaching Points

1. **FAST is a focused exam:** Detects FREE FLUID, not organ injury
2. **Positive FAST + hypotension = OR:** No CT needed; delays definitive care
3. **Negative FAST doesn't rule out injury:** Sensitivity ~80-90%; repeat if clinical concern
4. **Morison's pouch most sensitive:** Most dependent space in supine patient
5. **Look at diaphragm:** Fluid above diaphragm suggests hemothorax (eFAST)
6. **Probe positioning matters:** LUQ more posterior than RUQ
7. **FAST takes <5 minutes:** Should be part of primary survey
8. **Serial exams valuable:** If initially negative, may turn positive as bleeding continues

### Clinical Image
![FAST Exam - Positive Morison's Pouch](case_01_image.jpg)

**Image Description:** Ultrasound image of the right upper quadrant demonstrating a positive FAST exam with an anechoic (black) stripe of free fluid in Morison's pouch between the liver (above) and kidney (below), indicating hemoperitoneum.

**Attribution:** Image from Wikimedia Commons, FAST exam positive. Licensed under CC BY-SA 4.0. Source: https://commons.wikimedia.org/wiki/File:FAST-Exam-Positive.jpg

---

## Case 2: Cardiac Ultrasound - Pericardial Effusion with Tamponade

### Patient Demographics
- **Age:** 55 years
- **Sex:** Female
- **Occupation:** Office manager

### Chief Complaint
"I can't catch my breath and my chest feels tight."

### History of Present Illness
A 55-year-old female presents with progressive dyspnea over 2 weeks. She reports feeling "pressure" in her chest and notes she can only breathe comfortably sitting upright. She has had a non-productive cough and low-grade fevers. She has a history of breast cancer treated 2 years ago and recent travel to Asia for work.

### Initial Assessment

**ESI Level:** 2 - Respiratory distress with potential cardiac etiology

**First Impression:**
- Appearance: Anxious, sitting upright, unable to lie flat
- Work of breathing: Mildly labored
- Circulation: Pale, distended neck veins

**Vital Signs:**
- Heart rate: 116 bpm
- Blood pressure: 92/78 mmHg (narrow pulse pressure!)
- Respiratory rate: 24 breaths/min
- SpO2: 94% on room air
- Temperature: 37.8C
- GCS: 15

### Beck's Triad Assessment

| Finding | Present | This Patient |
|---------|---------|--------------|
| Hypotension | Narrow pulse pressure | SBP 92, pulse pressure 14 |
| JVD | Yes | Markedly elevated JVP |
| Muffled heart sounds | Variable | Difficult to assess |

**Pulsus Paradoxus:**
- BP during inspiration: 78/72
- BP during expiration: 94/78
- **Difference: 16 mmHg** (>10 = significant)

### Primary Survey

**Airway:** Patent
**Breathing:** Tachypneic, clear lungs (significant - no pulmonary edema despite JVD)
**Circulation:** Tachycardic, hypotensive, JVD, narrow pulse pressure
**Disability:** Alert, anxious
**Exposure:** No peripheral edema, no rashes

### Bedside Cardiac Ultrasound

**Indication:** Suspected pericardial effusion/tamponade

**Views Obtained:**

**1. Subxiphoid Four-Chamber View:**
- Large circumferential pericardial effusion
- **Right ventricular diastolic collapse** (pathognomonic for tamponade)
- Swinging heart (pendulum motion in large effusion)

**2. Parasternal Long Axis:**
- Confirms large effusion (>2cm throughout)
- RV collapse in diastole visible
- No wall motion abnormalities

**3. Parasternal Short Axis:**
- Circumferential effusion
- "Swinging" septal motion

**4. IVC Assessment:**
- IVC dilated (>2.5cm)
- Minimal respiratory variation (<50% collapse)
- **Indicates elevated RA pressure**

### Tamponade Physiology

**Echocardiographic Signs of Tamponade:**
1. **RV diastolic collapse** - most specific
2. **RA systolic collapse** - sensitive but less specific
3. **IVC dilation with minimal respiratory variation**
4. **Respiratory variation in mitral/tricuspid inflow** (>25%)
5. **Swinging heart**

**This patient has echocardiographic tamponade**

### Secondary Survey

**SAMPLE History:**
- Symptoms: Progressive dyspnea, chest pressure, orthopnea
- Allergies: None
- Medications: Tamoxifen, anastrozole
- PMH: Breast cancer (stage II, treated 2 years ago)
- Last Meal: This morning
- Events: 2-week progressive symptoms, travel to Asia

**Differential Diagnosis for Effusion:**
- Malignant effusion (breast cancer metastasis) - HIGH CONCERN
- Tuberculous pericarditis (recent travel)
- Viral pericarditis
- Uremic pericarditis
- Autoimmune disease

### Management

**Immediate Stabilization:**
- IV fluid bolus (temporizing measure - increases preload)
- Avoid positive pressure ventilation if possible (decreases preload)
- Prepare for pericardiocentesis

**Pericardiocentesis - Indication:** Tamponade with hemodynamic compromise

### Pericardiocentesis Procedure

**Ultrasound-Guided Approach:**

**Equipment:**
- 18g spinal needle or pericardiocentesis kit
- 50mL syringe
- Sterile prep, drape
- Ultrasound with linear or curvilinear probe
- Drainage catheter (Seldinger technique)

**Technique:**
1. Position patient at 45 degrees (effusion layers inferiorly)
2. Identify largest pocket of fluid (often subxiphoid or apical)
3. Sterile prep
4. Local anesthesia
5. Insert needle under real-time ultrasound guidance
6. Aspirate - straw-colored/bloody fluid
7. Place pigtail catheter over wire (Seldinger)
8. Connect to drainage bag

**This Patient:**
- Subxiphoid approach used
- 750mL serosanguinous fluid drained initially
- Pigtail catheter left in place
- Immediate improvement in BP (108/72) and symptoms

### Fluid Analysis

**Pericardial Fluid:**
- Bloody/serosanguinous
- LDH elevated (exudative)
- Cytology: **Malignant cells present - adenocarcinoma**
- AFB and cultures: Pending

**Diagnosis:** Malignant pericardial effusion with tamponade - metastatic breast cancer

### Disposition

**Admission:**
- Cardiology and oncology consultation
- Pericardial drain continued (200mL/day output)
- CT chest: Multiple pulmonary nodules, mediastinal lymphadenopathy
- Oncology staging workup

**Treatment Options for Malignant Effusion:**
- Pericardial window (surgical)
- Sclerotherapy via catheter
- Systemic chemotherapy
- Radiation (if localized)

**This Patient:**
- Pericardial window performed day 3
- Started on systemic therapy
- Discharged day 7 with oncology follow-up

### Teaching Points

1. **Bedside echo diagnoses tamponade:** RV diastolic collapse is specific
2. **Clinical + echo findings:** Beck's triad may be incomplete; echo confirms
3. **IVC assessment:** Plethoric IVC with minimal collapse = elevated RA pressure
4. **Narrow pulse pressure:** Early sign of tamponade
5. **Pulsus paradoxus:** >10 mmHg drop in SBP with inspiration
6. **Ultrasound-guided drainage:** Safer than blind approach
7. **Malignancy is common cause:** Especially lung, breast, lymphoma
8. **Temporize with fluids:** While preparing for definitive drainage

### Clinical Image
![Pericardial Effusion on Echocardiography](case_02_image.jpg)

**Image Description:** Parasternal long-axis echocardiographic view demonstrating a large circumferential pericardial effusion (asterisk) with the heart appearing to "swim" in the fluid, and early right ventricular diastolic collapse consistent with cardiac tamponade.

**Attribution:** Image from Wikimedia Commons, Pericardial effusion echo. Licensed under CC BY-SA 3.0. Source: https://commons.wikimedia.org/wiki/File:Pericardial_effusion_with_tamponade.gif

---

## Case 3: Lung Ultrasound - Differentiating Dyspnea

### Patient Demographics
- **Age:** 68 years
- **Sex:** Male
- **Occupation:** Retired firefighter

### Chief Complaint
"I can't breathe - it came on suddenly."

### History of Present Illness
A 68-year-old male presents with acute onset dyspnea that began 1 hour ago. He was sitting watching TV when he suddenly felt severely short of breath. He has a history of CHF but reports this feels "different" - more sudden onset than his usual exacerbations. He also reports recent 5-day car trip (limited mobility). He denies chest pain, cough, or fever.

### Initial Assessment

**ESI Level:** 2 - Acute respiratory distress

**First Impression:**
- Appearance: Anxious, moderate respiratory distress
- Work of breathing: Increased, using accessory muscles
- Circulation: Mildly tachycardic, not cyanotic

**Vital Signs:**
- Heart rate: 108 bpm
- Blood pressure: 142/88 mmHg
- Respiratory rate: 28 breaths/min
- SpO2: 88% on room air
- Temperature: 37.2C
- GCS: 15

### Differential Diagnosis for Acute Dyspnea

1. **Pulmonary embolism** (sudden onset, recent travel, prolonged immobility)
2. **CHF exacerbation** (history of CHF)
3. **Pneumonia** (less likely - no fever, cough)
4. **COPD exacerbation** (possible)
5. **Pneumothorax** (sudden onset)

**Clinical Question:** Is this CHF or PE? Treatment is very different!

### Lung Ultrasound - Rapid Bedside Assessment

**Equipment:**
- Portable ultrasound
- Linear or curvilinear probe
- 8-zone or 12-zone protocol

**Lung Ultrasound Findings:**

| Finding | CHF | PE | Normal |
|---------|-----|-----|--------|
| A-lines | Rare | Common | Common |
| B-lines | Diffuse bilateral | Usually none | <3 per zone |
| Pleural sliding | Present | Present | Present |
| Consolidation | Possible | Possible (infarct) | None |

### Examination Protocol (8-Zone)

**Each Hemithorax:**
- Upper anterior
- Lower anterior
- Upper lateral
- Lower lateral

### Findings in This Patient

**Right Lung:**
- Upper zones: A-lines (normal air artifact), pleural sliding present
- Lower zones: A-lines, pleural sliding present, no B-lines

**Left Lung:**
- Upper zones: A-lines, pleural sliding present
- Lower zones: A-lines, pleural sliding present, no B-lines

**Summary:**
- Bilateral A-lines (horizontal reverberation artifacts = air)
- NO B-lines (no pulmonary edema)
- Pleural sliding present (no pneumothorax)

**Interpretation:** **Normal lung ultrasound - NOT CHF**

### Additional Ultrasound Assessment

**Cardiac Ultrasound:**
- RV appears dilated (RV:LV ratio >0.9)
- Septal flattening ("D-sign")
- McConnell's sign: RV free wall akinesis with apical sparing
- IVC dilated, minimal collapse

**DVT Ultrasound (Lower Extremity):**
- Right common femoral vein: Non-compressible (DVT!)
- Right popliteal vein: Non-compressible (DVT!)

### Integrated Findings

| Finding | Interpretation |
|---------|----------------|
| Normal lung US (A-lines, no B-lines) | Not CHF |
| RV dilation + D-sign | Right heart strain (PE) |
| McConnell's sign | Highly specific for PE |
| DVT on compression US | Source of embolism |

**Ultrasound Diagnosis:** Pulmonary Embolism with RV strain

### Confirmation

**CT Pulmonary Angiography:**
- Bilateral pulmonary emboli
- Large saddle embolus at main pulmonary artery bifurcation
- RV dilation on CT

**Labs:**
- Troponin: 0.18 ng/mL (elevated - RV strain)
- BNP: 890 pg/mL (elevated - RV strain)
- D-dimer: >5000 ng/mL

**ECG:**
- Sinus tachycardia
- S1Q3T3 pattern (classic but not sensitive)
- Right heart strain pattern

### Risk Stratification

**Submassive (Intermediate-High Risk) PE:**
- Hemodynamically stable (not massive)
- RV dysfunction on imaging ✓
- Elevated troponin ✓
- Elevated BNP ✓

**Treatment Decision:**
- Anticoagulation (first-line)
- Consider thrombolytics if deteriorates
- Close monitoring in ICU

### Management

**Treatment:**
- Heparin infusion (weight-based)
- ICU admission for monitoring
- Serial troponins and echos
- Remained stable

**Transition:**
- Switched to apixaban day 3
- Discharged day 5
- 3-month minimum anticoagulation (provoked PE)
- Hypercoagulable workup if unprovoked

### Lung Ultrasound Patterns Summary

| Pattern | A-lines | B-lines | Sliding | Diagnosis |
|---------|---------|---------|---------|-----------|
| Normal | Yes | <3/zone | Yes | Normal |
| CHF | No | Diffuse bilateral | Yes | Pulmonary edema |
| Pneumonia | Variable | Focal | Yes | Consolidation pattern |
| Pneumothorax | Yes | None | **NO** | Absent sliding, lung point |
| **This patient** | **Yes** | **None** | **Yes** | **Normal lungs (think PE)** |

### Teaching Points

1. **B-lines = fluid:** Diffuse bilateral = CHF; focal = pneumonia
2. **A-lines = air:** Normal finding OR dry lungs (dehydration, PE)
3. **Absent B-lines in dyspnea:** Think PE, not CHF
4. **Lung US faster than CXR:** Results in <5 minutes at bedside
5. **Integration is key:** Combine lung US, cardiac US, DVT US for PE diagnosis
6. **McConnell's sign:** RV free wall akinesis with apical sparing - specific for PE
7. **RV:LV ratio:** >0.9 suggests RV strain (PE, pulmonary HTN)
8. **Point-of-care = point-of-decision:** Ultrasound guides immediate management

### Clinical Image
![Lung Ultrasound - A-lines vs B-lines](case_03_image.jpg)

**Image Description:** Side-by-side lung ultrasound images comparing normal A-lines (horizontal reverberation artifacts indicating air) with pathological B-lines (vertical hyperechoic artifacts extending from pleura to screen edge indicating pulmonary edema).

**Attribution:** Image from Wikimedia Commons, Lung ultrasound B-lines. Licensed under CC BY-SA 4.0. Source: https://commons.wikimedia.org/wiki/File:LungUltrasoundBLines.jpg