FAST - What are the boundaries
Peter Jones
Outline
F.A.S.T.
Dr Peter Jones FACEM, Dip EBHC (Oxon)
Emergency Medicine Specialist
F.A.S.T. Objectives
• What is FAST?
• Critical Appraisal of the Evidence for FAST
• Limitations
• Cases to illustrate
• What does FAST add to Trauma Management?
• Prehospital FAST
• FASTER!
F.A.S.T.
• Focused
• Assessment
• Sonography
• Trauma
Role of F.A.S.T.
Is there free fluid?
F.A.S.T. Free Fluid
F.A.S.T. Limitations
F.A.S.T. Limitations
Clear Indication for OT, FAST ‘Contraindicated’
Intrinsic insensitivity
• 100 stable blunt trauma patients, negative DPL
• Fluid Infused, participants blinded to volume
– Mean volume before positive = 619 mL.
– 10% detected < 400 mL
– Sensitivity at one litre was 97%
F.A.S.T. Limitations
Intrinsic insensitivity
vonKuenssberg et al. 2003 Oct;21(6):476-8.
• 7 Blunt Trauma Patients, negative FAST/DPL
• Fluid infused (not blinded)
– minimum volume detected with pelvic views
– mean 157mL
– median 100mL (100,400mL)
Emergency Medicine Australasia 2003 15 (1), 54–62 and 42-48
Vassiliadis, Edwards, Larcos, Hitos
Focused assessment with sonography for trauma patients by clinicians: Initial experience and results
Jones, Peak, McClelland, Holden, Higginson, Gamble
Emergency ultrasound credentialling for focused assessment sonography in trauma and abdominal aortic aneurysm: A practical approach for Australasia
Comparison
Auckland
4 Sonographers, 13 months
102 patients, 13 FF
25-35 scans, median 30
Sn 85%
Sp 97%
LR+ 28.3
LR- 0.15
Westmead
23 Sonographers, 20 months
132 patients, 26 FF
1-31 scans, median 4
Sn 81%
Sp 98%
LR+ 40.5
LR- 0.19
Radiology 2005, 236(1) 102-11 (Level 1a)
377 potentially relevant articles
62 selected,1 RCT
↑ quality = ↓ sensitivity
Sn 66% (56.2-75.8) vs 77.8% (72.1-83.5)
Specificity constant
Sp 99.4% (99.2-99.6%)
Radiology 2005, 236(1) 102-11
“Positive F.A.S.T. is decisive
Negative F.A.S.T. is not”
F.A.S.T. Limitations
Intrinsic
• Negative ≠ No Injury
– Solid Organ (up to 1/3 no FF, 2/3 missed)
– Hollow Viscus
– Retroperitoneum
– Small Amounts FF
• Negative Now ≠ Negative Later
F.A.S.T Limitation
Small Amounts Fluid / Solid Organ / Retroperitoneal
Suboptimal Patient Preparation / Sonographer Ability
F.A.S.T. Sonographer Ability
Small Amounts Fluid / Hollow Viscus
Hollow Viscus / Retroperitoneum / Indication for OT
Patient Factors
F.A.S.T.
Is Management Changed?
Cochrane Review 2005, Issue 3 (Level 1a-)
Outcome Risk Studies
Mortality 1.4 [0.94-2.08] 2
Use of CT -0.46 [-1.04-0.13] 4
Use of DPL 0.12 [-0.04-0.28] 3
Laparotomy .02 [-0.03-0.06] 2
Non-therapeutic 0.53 [.03-8.51] 1
Time to diagnosis -98 [-121-74] 1
Ann Emerg Med 2006; 48(3) 227-35 (Level 1b)
• Primary Outcome Measure
– Time to Operating Theatre
• Secondary
– Use of CT, Length of Stay, Complications, Cost
• Power Analysis
– 246 patients: 40% reduction in time, power 90%, alpha 0.05
• Enrolled 262, 217 completed the study (82%)
• Intention to Treat
Ann Emerg Med 2006; 48(3) 227-35
Primary Outcome Measure
Time to Operating Theatre
PLUS(29/111) No PLUS(34/106)
57min (41-70) 166min (90-178)
Ann Emerg Med 2006; 48(3) 227-35
Secondary PLUS NoPLUS OR
CT % 53 (44-62) 85 (76-92) 0.16 (0.07-0.31)
LOS (days) 4 (1,8) 5 (2,12)
Complications% 21 (11-27) 38 (28-46) 0.17 (0.02-0.86)
Cost $10.6k $43.8k (IQR overlapped)
J Emerg Med. 29(1) 15-21
• Derivation Study (Level 2b)
– Retrospective database review +ve FAST
– Factors
• FF: RUQ / RUQ + Other / Other
• Age >60
• Abdominal Tenderness
• Hypotension <90mmHg
• Chest Trauma
• Pelvic #
• Femur #
– Registered sonographers
J Emerg Med. 29(1) 15-21
• Derivation Study (Level 2b)
– Regression Tree Analysis
– Outcome: Therapeutic laparotomy
– Sample size calculated = 70 (included 230)
– Interobserver reliability for variables k>0.8
– Most Important Variable = RUQ fluid
• 105/144 (73, 64-80%) TL
J Emerg Med. 29(1) 15-21
• Derivation Study (Level 2b)
– If no RUQ fluid (35% still needed TL)
• Hypotension
• Femur #
• Abdo tenderness
• Age >60
– Sn 100, 98-100%: Sp 13, 7-21%
– Non Therapeutic Laparotomy in 1/3
F.A.S.T. Pre-hospital
• Walcher et al. Br. J. Surg. 2006;93:238-242
– Multicentre, physician/paramedic
– Convenience cohort, 230 (14% of eligible) (Level 3b)
– 93% acceptable scans: Sn 93%, Sp 99%
– Pre-hospital time unchanged 95%
– Management changed 21%
• +ve FAST (n=28): Reduce scene time / reduce IV fluids
• Results rang ahead = better ED preparation
• Change destination 20%
F.A.S.T. Pre-hospital
• Melanson et al. Prehosp. Emerg. Care 2001; 5(4): 399-402
– Feasibility of Aeromedical FAST, 71 BT (Level 4)
– Flight crew
– 48% unable to scan
• Time 2/3
• Access
• Combative
– Technical Difficulties 10%
• Ambient light
• Machine failure
F.A.S.T. Pre-hospital
Sztajnkrycer MD Prehosp Emerg Care. 2006 10(1):96-102.
• Retrospective 359 patients, 286 START yellow
– 20 had positive FAST, only 6 required OT <24 hours
– 19 Inconclusive FAST
– Sn 47% Sp 96%
– Not a useful addition to Simple Triage / Rapid Treatment
(Level 4)
F.A.S.T. Military
• Miletic et al. Military Medicine 1999 164(8)600-02
– 94 War casualties BAT / PAT (22 injuries) (level 3b)
– Sn 86% Sp 100%
• Several case reports/series
• Teleradiology
• Disasters
• FASTER = Chest and Extremity Trauma
F.A.S.T. Pre-hospital
Sargsyan et al. J Trauma 2005 58(1) 35-39
• Astronaut
• Remote guided FAST
– Footstraps
– Good views
– 5.5 minutes
– 2 second delay
– Transmission blackouts
F.A.S.T. Paediatrics
• Advantages
– Non-invasive
– No radiation
– No sedation
– Rapid
– Repeatable
• Disadvantages
– Missed Injuries
– Do you act on a +ve?
F.A.S.T. Paediatrics
• Soundappen et al. Injury 2005 36 970-975
– Prospective, blinded consecutive 85 BAT <16 ys. (Level 1b)
– Trauma Fellow
• Sn 81% Sp 100%
• Soudack et al. J. Clin Ultrasound 2004 32(2) 53-61
– Retrospective, 313 consecutive BAT <17ys. (Level 2b)
– Radiologists
• Sn 92.5%, Sp97.2%
• Holmes et al. J Ped Surg 2001 36 (7) 968-973 (level 3b)
– Prospective, convenience sample 224/641 BAT <16ys.
– Trained sonographers
• Sn 82% Sp95%
F.A.S.T. Pregnancy
• Advantages
– Non-invasive
– No radiation
– Rapid
– Repeatable
• Disadvantages
– Missed Injuries
– Landmarks distorted
– ?intrauterine or FF
– Uterus not well seen
– NOT = obstetric US
F.A.S.T. Pregnancy
• Richards et al. Radiology 2004 233(2) 463-70
– Retrospective consecutive 328 patients (23 BAT) (Level 2b)
– Sn 61% Sp 94.4%
• Goodwin et al. J. Trauma 2001 50(4) 689-93
– Retrospective convenience sample 127 BAT patients (Level 3b)
– Sn 83%, Sp 98%
F.A.S.T. Pelvic Fracture
F.A.S.T. Chest
• Pneumothorax
– Similar literature: 4 Level 3 cohort studies >100pts
– US consistently more sensitive than supine AP CxR
Study US CXR
– Kirkpatrick 48.8% 21%
– Blaivas 98.1% 75%
– Soldati 98.2% 53.6%
– Zhang 86.2% 27.6%
F.A.S.T. Chest
• Haemothorax
– McKewan J Emerg Med 2007 24(8)581-2
• Review 6 papers: US more sensitive than CXR (level 3a)
• Conutusion
– Soldati Chest 2006 130(2)533
– Mixed cohort 88 patients CT as reference (level 3b)
Sn 94.6% Sp 96.1%
Better than CXR Sn 27%
F.A.S.T. Fracture
• Several small Case Series (Level 4)
• Marshburn et al. J Trauma 2004 57(2) 329-32 (level 3b)
– 58 patients
– US > Physical Exam
– Sn 92.9% Sp 83.3%
F.A.S.T. Fracture
Beyond Trauma
S.L.O.H. not F.A.S.T
Beyond Trauma
S.L.O.H. not F.A.S.T
?
Ann Emerg Med 2006; 48(3) 227-35
J Trauma 2006; 60(4)785-91
‘Before and after’ FAST
Hypothetical Controls
Change in management in 59/180 (32.8%)
Preventing
1 Laparotomy
23 CT scans
15 DPL
J Trauma 2006; 60(4)785-91
No difference between FAST and no-FAST groups!
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Ministry of Health
