Emergency Ultrasound (EUS) 教學(2)

急診超音波在外傷之應用 (E-FAST)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

Clinical tools for trauma evaluation

• Diagnostic peritoneal lavage

• Computed tomography

• Ultrasonography

Diagnostic Peritoneal Lavage

• 優點– 對腹腔內出血的辨識具高敏感度

– 106 RBC/mm3 • 1L 灌洗液有 20 ml 的血

– 可在床邊執行– 可在 10-15 分內完成– 早期診斷腸道破裂

• 缺點– 過度敏感，可能造成高的剖腹手術率

– 具侵入性– 懷孕或之前曾多次手術患者身上不易執行

– 不易重覆進行

CT Scan

• 優點– 可辨識特定傷害– 可辨識中空器官及後腹腔傷害

– 高敏感度及高特異性– 非侵入性

• 缺點– 昂貴– 需長時間– 需移出急救區– 僅適合穩定患者– 懷孕者不宜

FASTFocused

Assessment with

Sonography for

Trauma

Focused Abdominal Sonography in Trauma

FAST should be SLOH

systematic look for occult hemorrhage

FAST

• 優點– 能在床邊 5 分內完成– 非侵入性– 可重覆進行– 對 free fluid 的敏感度及特異性相當於 DPL & CT

• 缺點– 操作者的經驗– 可能無法判定特定傷害– 對中空器官及後腹腔傷害辨識度差

– 肥胖及皮下氣腫會干擾檢查結果

FASTFocused Assessment with Sonography for

Trauma

• identify free fluid

• evaluate for pneumothoraces• quantify the degree of free fluid • follow the accumulation of free fluid

Overview of potential intraabdominal and thoracic spaces

Movement patterns of free fluid

FAST – Specialty Societies

• Established clinical role in Europe, Australia, Japan, Israel

• German Surgical Society requires candidates’ proficiency in ultrasound

• United States– US in ATLS– US policies by frontline specialties

• American College of Surgeons• ACEP,SAEM & AAEM

When is Trauma Ultrasound Most Useful?

• Unexplained hypotension• Ongoing emergent bedside

procedures • Guide treatment before transfer• Repetitive and serial exams• Penetrating trauma in upper

abdomen or lower chest

Clinical indications for FAST

• acute blunt or penetrating torso trauma

• trauma in pregnancy• pediatric trauma• subacute torso trauma • undifferentiated hypotension

FAST

• 基本的四個介面– Subxiphoid– RUQ– LUQ– Pouch of

Douglas

FAST

• 掃描介面數增加 敏感度增加

• 可協助辨識肋膜積液• 胸腔內 20cc 的積液即可被偵測upright CXR 50-100ccsupine CXR 175cc

• 敏感度 >96%, 特異度 99-100%

FAST的臨床經驗• 腹腔內液體

– 敏感度 82-98%, 特異度 88-100%

• 單獨掃描 Morison’s pouch 的敏感度為 36-82%

• 敏感度會因下列原因增加– 增加掃描介面數– Trendelenberg 姿勢– 增加檢查次數

• 約 250cc 的游離液體即可被掃描 (100ml)– Morison’s pouch

• Strip ~ 250ml; 0.5cm strip ~ 500ml

FAST的臨床經驗• 實質器官受傷的敏感度

– 所有器官 : 40%– 脾臟 : 33-94%

• 中空器官受傷– 敏感度 : 57%

• 後腹腔受傷– 辨識出血的敏感度 <60%

RUQ View

RUQ View

RUQ View

RUQ View

Fluid in Morison’s pouch

Fluid in Morison’s pouch

Fluid in Morison’s pouch

RUQ View for pleural fluid

RUQ View for pleural fluid

Pleural fluid

Positive FAST scan

Positive FAST scan

並非所有的液體都是血• Ascites• Ruptured Ovarian Cyst• Lavage fluid• Urine from ruptured bladder

Cardiac Views

Subxiphoid view Parasternal long axis view

Subxiphoid View

Subxiphoid View

Parasternal Long Axis View

Cardiac tamponade

心臟鈍挫傷• 不易由 FAST 評估的傷害

– Valvular incompetence– Myocardial rupture– Intracardiac thrombosis– Ventricular aneurysm– Coronary Thrombosis– Intra-cardiac Thrombosis

LUQ View

LUQ View

Fluid surrounding the spleen

Pelvic View (Longitudinal)

Pelvic Scan

Pelvic View (Longitudinal)

Pelvic View (Longitudinal)

Small amount of free fluid in pouch of Douglas

Large amount of free fluid surrounding the uterus

Pelvic View (Transverse)

Probe position for transverse pelvic view

Probe position for transverse pelvic view

US-based scoring system

• Points (0-8)– Morrison’s pouch 2pt if ≧ 2cm (1pt if < 2cm)– Douglas’s pouch 2pt if ≧ 2cm (1pt if < 2cm)– Perisplenic space 1pt– Paracolic gutter 1pt– Floating intestinal loops 2pt

• Score 3 ~ 1000ml of fluid• Score 3: 96% required laparotomy

(24/25)• Score < 3: 38% required laparotomy (9/24)

Huang MS, et al.Trauma 1994;36:173-77

Chest US for PTX(Extended, E-FAST)

• Lung sliding: rule out PTX– Seashore sign– Stratosphere sign

• Comet tail artifact: rule out PTX• Lung point: rule in PTX

Chest US: Bat sign

Normal lung artifacts

Power Doppler of normal lung

Seashore sign

Lung point & Stratosphere sign

Pearls and Pitfalls

• Repeat FAST as needed• Consider reverse/Trendelenburg position• Visualize full perihepatic and perisplenic area • Move probe caudad and posterior for better

perisplenic view• Subcutaneous emphysema• Pericardial fluid v.s. fat• Pleural effusion v.s. pericardial effusion• Perinephric fat v.s. fluid• Free fluid isn’t always blood

Pearls and Pitfalls

• Not all abdominal injuries produce free fluid• Clotted blood generate various echogenicity• The pelvic view prior to Foley catheter• Chest US detect a PTX directly under the probe• Lack of pleural sliding

– pneumothorax, mainstem intubation or just poor ventilation

• Comparing both side of the chest is helpful but may be confusing if bilateral pneumothoraces are present

• Dark room may provide an improved display of ultrasound findings

SKH - FAST

“ The most important preoperative objective in the management of the patient with trauma is to ascertain whether or not laparotomy is needed, and not the diagnosis of a specific organ injury”

Take Home Message

• 急診超音波的入門第一課 : FAST• 對危險機轉或生命徵象不穩定患者，應優先考慮 FAST

• 初學者使用 FAST 的主要目的在掃描有無free fluid ，不可用來做為 rule out 的工具

• 增加掃描介面和次數可以提升診斷正確率• 稍具經驗者，請延伸至 E-FAST• 請記得找資深有經驗的醫師確認，切記 !!