急診超音波簡介

原理、心臟、胸部、骨骼肌肉軟組織

新光醫院急診醫學科

陳國智醫師

中華民國醫用超音波學會指導醫師

1

急診超音波的角色為何 ?

2

臨床情境

• 50M, MVA patient, HR 130bpm, BP 70/40

– Internal bleeding ?

• 85M, sudden onset right flank pain, 8/10

– Renal colic or AAA ?

• 48F, RUQ pain with fever

– Cholecystitis ?

• 28F, low abdominal pain with shock, EIA (+)

– Ectopic pregnancy ?

3

急診超音波三部曲

•操作者

–熟悉超音波的機器

•判讀者

–熟悉超音波影像及解剖學

•決策者

–與臨床工作整合協助決策 4

Cardiovascular Assessment

5

Heart Anatomy

Thoracic Cavity

Cardiac Axes

Transducer consideration

Classic routes of heart

Subxiphoid Four-Chamber View

Subxiphoid Short-Axis View

Subxiphoid Long-Axis View

(IVC view)

Central Venous Pressure

IVC size for volume assessment

IVC size (cm) Resp. change RA pressure

(cm)

<1.5 Total collapse 0-5

1.5-2.5 >50% collapse 5-10

1.5-2.5 <50% collapse 11-15 (>10)

>2.5 <50% collapse 16-20

>2.5 No change >20

IVC size assessment

Parasternal Long-Axis View

Parasternal Short-Axis View

Parasternal Short-Axis View

papillary muscle level

Parasternal Short-Axis View

mitral valve level

Parasternal Short-Axis View

aortic valve level

Mercedes Benz sign

Apical Four-Chamber View

Primary Indications

• Detection of pericardial effusion and/or

tamponade

• Evaluation of gross cardiac activity during

CPR

• Evaluation of global LV systolic function

Secondary Indications

• Gross evaluation of intravascular volume

status and cardiac preload

• Indentify acute RV dysfunction and/or

acute pul. HTN for chest pain / dyspnea/or

hemodynamic instability

• Pericardiocentesis guidance

Limitations for EUS

• Focal wall motion abnormality

• Diastolic dysfunction

• Valvular abnormalities and function

• Intracardiac mass or thrombus, ventricular

aneurysm, septal defect, AD, myocarditis,

HCM, and vegetation

Technical limitations

• Thorax abnormalities

• Pulmonary hyperinflation

• Obesity

• Patient can’t cooperate

• Subcutaneous emphysema

Key component

• Evaluation of pericardial effusion – Anechoic or hypoechoic fluid

– Complex echogenicity: inflammation, infection, malignancy, hemorrhage

• Classification – None

– Small, <10 mm in width in dastole, non-circumferential

– Moderate, circumferential, not greater than 10 mm

– Large, 10-20mm in width

– Very large, > 20 mm and/or evidence of tamponade

Pericardial Effusion

Pericardial Effusion

Key component

• Echocardiographic evidence of tamponade

– Diastolic collapse of any chamber in the

presence of moderate or large effusion

– Hemodynamic instability with a moderate or

large pericardial effuion

Cardiac Tamponade

US Guided- Pericardiocentesis

• Subcostal approach

– Traditional approach

– Blind

– Increased risk of injury to liver, heart

• Echo-guided

– Left parasternal preferred for needle entry or…

– Largest area of fluid collection adjacent to the chest wall

Technique

Pericardial Effusion / Tamponade

• Tamponade

– Clinical diagnosis

– Circulatory collapse due to pericardial effusion

• Subxiphoid approach is the best window

– Effusion location – inferior & posterior

• Echo evidence of tamponade

– Diastolic collapse of the right side of the heart

– Plethoric IVC without inspiratory collapse

Chest

35

Why such a delay for lung

ultrasound to become popular ?

Principles of Lung Ultrasound

1. Dependent versus Nondependent disorders

2. Lung surface is extensive

3. All lung signs arise from the pleural line

4. Analyze artifacts

5. Dynamic signs

6. Acute disorders contact the thorax surface

7. A simple & 2-D device meets this task

Earth-Sky Axis

• Fluids want to descent, gases to rise.

• Lung disorders

– Dependent: PLE, consolidation, ….

– Non-dependent: PTX, interstitial syndrome, ….

• Define the scanning situation

Patient position

Landmarks of the chest wall

• Lung surface: 1500cm2

• Position: as stethoscope

• 9 areas – Anterior zone (1-4)

– Lateral zone (5,6)

– Posterior zone (S,M,L)

• 4 stages – 1. anterior

– 2. lateral

– 3. portion of posterior

– 4. posterior

Landmarks of the chest wall

• Lung surface: 1500cm2

• Position: as stethoscope

• 9 areas – Anterior zone (1-4)

– Lateral zone (5,6)

– Posterior zone (S,M,L)

• 4 stages – 1. anterior

– 2. lateral

– 3. portion of posterior

– 4. posterior

Degree of aeration and US signs

Degree Pathologic disorder Ultrasound pattern

100% Pneumothorax A lines & Lung sliding (-)

98% Normal lung A lines & Lung sliding (+)

95% Thickening of the interlobular septa B7 lines

80% Ground-glass areas B3 lines

10% Alveolar consolidation Hepatization & air bronchograms (++)

5% Atelectasis Hepatization & air bronchograms (-)

0% Pleural effusion Anechoic collection

Key concepts: Air versus Water

Normal Landmark

Bat sign

Rib

Pleural line

A-line

Normal dynamic lung pattern

Lung sliding: all-or-nothing rule

”Seashore sign”

Rule out pneumothorax

Normal static lung pattern

A line & B line

A lines and B lines cannot be visible at the same location

Comet-tail artifact

”Lung rockets”

B-line

Rule out pneumothorax Indicate interstitial syndrome

88F with respiratory failure

47

Normal versus APE

Comet-tail artifact

E-line

Parietal emphysema

Pneumothorax

Rule out pneumothorax

all-or-nothing rule

Stratosphere sign (Barcode Sign)

Pneumothorax

Lung sliding (-) Sensitivity 100% Specificity 78% A line sign (No B line) Sensitivity 100% Specificity 60%

Lung point Sensitivity 66% Specificity 100%

Lichtenstein DA, et al. Inten Care Med 2000;26:1434-1440

Pneumothorax

Explanation of lung point

Lung point Sensitivity 66% Specificity 100%

Lichtenstein DA, et al. Inten Care Med 2000;26:1434-1440

Pneumothorax

Signs of PTX

• No lung sliding

• No B line

• No lung pulse

• Presence of lung point

56

MSK

57

Outlines

• US anatomic considerations

• Skin and soft tissue infection

• Long Bony fracture evaluation

正常組織超音波影像 • Skin

– Echogenic

• Subcutaneous tissue – Hypoechoic

– Traverse by irregular strands of hyperechoic connective tissue

• Fascial planes – Hyperechoic; regular thickness

• Muscles – Striated appearance on long axis scan

• Tendon – Fibrillar; echogenic

• Vascular structures – Anechoic (Artery versus Vein)

• Lymph nodes – Irregular, circular, echogenic; with hypoechoic rim

• Bones – Echogenic cortices and dense acoustic shadows

掃描注意事項

• 高解析線形探頭 (5-10MHz)為第一首選

• 注意深度(depth)和焦點(focus)的設定

• 適當應用探頭施壓

• 至少掃描兩個介面 (longitudinal & transverse)

• 考慮和對側比較 & 呈現在同一畫面 (Split screen)

• 如何改善掃描品質 – Stand-off pad

– Water/gel-filled glove

– Water bath technique

Water/gel-filled glove

EUS在皮膚 & 軟組織感染的應用

• 須熟悉正常超音波軟組織影像

• 認識週遭組織及結構

• 協助設定最佳切除及引流路徑

• 正確診斷不明顯膿瘍

診斷

• 正確定位不明顯膿瘍

定位

• 協助膿瘍引流

處置

皮膚 & 軟組織感染

• Cellulitis – Cobblestone-like appearance

• Subcutaneous abscess – Variable appearance

– Most: hypoechoic; spherical mass

– Content: • Hyperechoic sediment

• Septae

• Gas

• Isoechoic or hyperechoic

• Liquefied pus – induced motion of the

content

• Necrotizing fasciitis – Marked thickened of SC layer

– A layer of anechoic fluid, • greater than 4 mm

• adjacent to deep fascia

– Subcuatneous gas • Acoustic shadow

• Reverberation artifact

Cellulitis

• Nonspecific

• Indicative of edema

• Skin

• Subcutaneous tissue

• Compare to unaffected side

Normal v.s. Cellulitis

EUS improves accuracy of superficial

abscess detection

Squire BT, et al. AEM. 2005;12:601-606

NTUH experience

• diffuse thickening of the SC tissue

• a layer of fluid accumulation more than 4 mm in depth along the deep fascial layer

• 66 patients (17,NF)

• Sensitivity: 88.2%

• Specificity: 93.3%

• PPV: 83.3%

• NPV: 95.4%

• Accuarcy: 91.9

Yen ZS, et al. AEM. 2002;9:1448-1451

骨折評估

• 肋骨骨折

• 胸骨骨折

• 長骨骨折

• 堅困環境骨折

• 骨折復位

• 脫位復位

• FASTER

骨折評估

• 骨表面產生不連續線條

• 骨折周圍低回音血腫

• 掃描時注意最痛點

• 至少進行兩個介面掃描

Rib

Rib fracture

Rib fracture

Normal sternum

Sternal body fracture

Femur

Femoral shaft fracture

Tibial shaft fracture

JUICE BAR

Juice119.pixnet.net

juice119@gmail.com

78