Emergency Department Ultrasound at Auckland Hospital FAST and AAA: The first year

Objectives The role of FAST History of ED ultrasound at Auckland Hospital The ultrasound credentialling process How we performed in the first year How we compare to the rest of the world Where we go from here

FAST Focused Assessment Sonography Trauma

FAST Integral part of initial trauma workup Proven –Quick –Safe –Reliable –Reproducible –Repeatable

FAST Pitfalls –Poor sonographer –Poor scan Air Obesity –Negative FAST doesn’t exclude injury! –Failure to serially examine the patient

History 1998 Purchased portable ultrasound machine 1998 First Australasian FAST course Sporadic use of ultrasound Dec 2000 Formal Emergency Ultrasound credentialling program Feb st credentialled ED sonographers

The Credentialling Process - Background Radiologist Clinician Radiologist Clinician

The Credentialling Process - Background Much debate in literature last 10 years Consensus meeting Each department decide own credentialling process 200 scans and ongoing audit Subsequent literature –Shackford yr experience 50 scans Suggests acceptable error rates

The Credentialling Process - Background Workshop beneficial –Rozycki 1996 Exit exam –Sisley 1999

The Credentialling Process - Background American College of Emergency Physicians 2001 –8 workshop hours –25 scans in each of 6 areas –Can be partially credentialled Only 1/76 departments met criteria –Boulanger 2000

The Credentialling Process - Background Australasian College for Emergency Medicine –16 workshop hours –25 Accurate scans for FAST –15 Accurate scans for AAA –>50% clinically indicated –Proctored by credentialled/ultrasound qualified person –Exit exam

Auckland ED Adopted ACEM guideline December sonographers –Satisfied workshop requirement –Scans should not alter management –All measured against ‘gold standard’ –Proctored by radiologist –Standardised form –Monthly/bimonthly –Modified criteria for scans –100% clinically indicated –Exit examination February 2001

Results FAST 1 ED registrar ‘credentialled’ by June 2001 –79% Indicated scans 2/3 ED Specialists credentialled by Feb 2002 –All scans clinically indicated

Results FAST For Detection Any Free Fluid 113 scans in 102 patients over 13 months –9 scanned by 2 sonographers –1 scanned by 3 sonographers

Results FAST (Any Free Fluid) n=113 TP20 TN83 FP3 FN7 Sn74.1% Sp96.5% PPV87% NPV92% Accuracy 91.2%

Results FAST (Laparotomy or Extra Investigation) n=107 TP11 TN89 FP5 FN2 Sn84.6% Sp94.7% PPV68.8% NPV97.8% Accuracy 93.5%

Results FAST Existing literature vs gold standard, novice sonographers 3 studies Sn69-79% Sp96-98% vs clinical observation and experienced sonographers Sn80-98% Sp>90%

Errors FAST 7 FN –5/7 Trivial fluid, conservative management –1 penetrating trauma with minor injury –1 blunt trauma bladder injury, stable All views adequate and correct interpretation according to radiologist

Errors FAST 3 FP –1 “ascites” –1 “?pericardial effusion” –1 Retroperitoneal and abdominal wall haematomas Adequate views but incorrect interpretation

Result of errors FAST 1 CT scan thorax for “?Pericardial effusion”

Emergency Department Ultrasound for AAA 2 Case series in literature

Results AAA 66 Scans in 58 Patients in 12 months –5 Scanned by 2 sonographers –1 Scanned by all 4 3/4 sufficient scans to meet requirement

Results AAA n=66 TP26 TN39 FN1 FP0 Sn96.3% SP100% PPV96.3% NPV97.5% Accuracy 98.3%

“Error” AAA Free air obscured 6cm AAA Free fluid detected in Morison’s and Splenorenal recesses Found to have perforated DU

AAA Existing Literature Shuman 1998 –n=60 Sn 97% Sp100% Kuhn 2000 –n=68 Sn100% Sp95%

Time Taken to Scan FAST median 5min (1-20) AAA median 3.5 (1-16) Similar to literature published

FAST Learning Curve Debate about this Shackford only author to look at initial experience –Suggests 10 scans before proficient –Showed ‘Institutional learning curve’ –12 Individuals = wide variation in error rates –Only 4/12 had >25 scans in 4 years

FAST Learning Curve

Error rate <10% Most ‘errors’ clinically insignificant Individual variation

Potential Bias Patients not consecutive –Opportunity for pre-selection of patients Individual sonographers could discard unsatisfactory scans prior to proctoring

Summary Emergency Department Ultrasound is established in Auckland Hospital Accuracy mirrors existing literature Pitfalls exist and should be considered

The future Credentialling continues Credentialled sonographers record in notes Clinical management may alter Ongoing audit Expanded indications –Unstable patient with abdominal pain Is there free fluid?

Case 1 37f –4hr Abdominal pain –Collapse and seizure –Shock –Arrives ED 1755 –SLOH 1806

Case 1 OT 1815

Case 2 28f –1/2 hr Abdominal pain –HR 84, SBP 90, RR 16 –Arrives ED 0910 –S/B registrar 1000 –SLOH 1018

Case 2 Urine pregnancy test 1025, positive

Case 2 OT 1055

Case 3 19m –Fall from tree –Collapse at home –Fighting en route –Arrives ED 1635 –FAST 1645

Case 3 OT for thoracotomy