FA S TFAST - Focussed Abdominal Sonographyin Trauma The third is the retroperitoneal abdomen, which con- tains the kidneys, ureters, pancreas, abdominal aorta,1. Introduction and inferior vena cava. The fourth is the true abdomen, which contains theFocussed Abdominal Sonography in Trauma (FAST) small and large intestines, the uterus (if gravid), and thehas rapidly become an accepted method of injury as- bladder (when distended).sessment in blunt abdominal trauma. Many traumamanagement guidelines have adopted FAST as a pivotalaxis in the decision –making algorithm. It is the currentgold standard for the detection of intra-abdominal When performing a physical examination of the ab-bleeding in the unstable hypotensive patient with blunt domen, a common division of surface landmarks mayabdominal trauma. The technique of FAST is of inter- be used to divide the abdomen into 9 partsest to all clinicians involved in the care of serious HC – Hypochondrium (left and right upper quadrants)trauma patients – surgeons, emergency physicians, in- E – Epigastriumtensivists and anaesthetists. L – Loin (left and right) U – Umbilicus“The most important preoperative objective in the IF – Iliac Fossa (left and right)management of the patient with abdominal trauma is HY - Hypogastriumto ascertain whether or not a laparotomy is needed, andnot the diagnosis of specific injury” - Polk 1983If one agrees with the statement above, then ultra-sound has many important advantages over traditionalmethods of abdominal assessment in trauma. Whencompared to physical examination, diagnostic perito-neal lavage (DPL) and computerised tomography (CT)it is non-invasive, rapid, portable and accurate. DPL isparticularly sensitive, but not all patients with a positiveDPL would require laparotomy. CT allows localisationof injury site and grading of severity but it is time-consuming and requires a stable co-operative patient.Therefore, FAST has a specific role in the unstable pa-tient with abdominal trauma, and according to currentevidence is a highly useful modality in deciding whichpatients require emergency laparotomy.2. Anatomy of the peritoneum relevant to FASTThe abdomen can be arbitrarily divided into 4 areas.The first is the intrathoracic abdomen, which is theportion of the upper abdomen that lies beneath the rib Fig 1. Surface areas of the abdomencage. Its contents include the diaphragm, liver, spleen,and stomach. The rib cage makes this area inaccessiblefor palpation and complete examination. The second is the pelvic abdomen, which is defined bythe bony pelvis. Its contents include the urinary blad-der, urethra, rectum, small intestine, and in females, theovaries, fallopian tubes, and uterus.
FA S T 2.1 Sonoanatomy and technique of FAST The sole goal of FAST is to detect free intraperitoneal fluid. Diagnosis of organ injury, localisation of organ injury and grading of injury severity are more suited to formal ultrasound scanning or CT. The FAST examina- tion is designed for rapid assessment; there are just 4 scanning positions in the examination. These are win- dows of ultrasound scanning and do not correspond to anatomical descriptions of planes such as sagittal or coronal. 1. Perihepatic – structures in the right upper quadrant (RUQ) are visualised – right lobe of liver, kidney and the hepatorenal space 2. Perisplenic – structures in the left upper quadrant (LUQ) are visualised – spleen, kidney, perisplenic area 3. Pelvis – structures in the pelvic cul de sac are visual- ised – Pouch of Douglas between bladder and uterus in females, or rectovesical pouch in males 4. Pericardial – essentially a subcostal echocardia- graphic view of the heart, liver and pericardiumFigs 2 and 3. Plain abdominal radiograph and key Fig 4. The 4 scanning windows of the FAST examina-Plain abdominal films are unhelpful in acute trauma tion – clockwise from top = pericardial, perisplenic,and are not part of the trauma radiography series. This pelvic and perihepaticnormal film helps to demonstrate organ relationships.Note the close interposition of the liver and right kid-ney, and the spleen and left kidney.
FA S TAttaining FAST views requires basic knowledge of The probe is placed in the right mid to posterior axil-ultrasound physics and familiarity with the ultrasound lary line at the level of the 11th and 12th ribs. Angle themachine, correct transducer selection and depth set- probe until the hepatorenal space (Rutherford-tings and correct application of the probe. Knowledge Morrison Pouch) is seen. In the normal patient theof physics and knobology of the ultrasound machine liver and kidney are closely aligned with with no visiblewill be assumed in this tutorial. It is recommended that fluid. Because this is the most dependant zone of thecandidates are fully able to describe and eliminate arti- upper abdomen, intraperitoneal fluid should collectfacts and anatomic pitfalls, and to fully operate the ma- here first. Fluid is generally hypoechoic and is seen as achine and optimise ultrasound images before progress- dark or black stripe between the liver capsule and theing to scanning “live” patients. fatty Gerota’s fascia of the kidney. As little as 70mls of fluid may be visualised as a positive scan in this area.It is also recommended that an ultrasound machinewith live 2-D mode (rapid B-mode) and transducer fre-quencies between 3-6MHz be used. Optimal depth set-tings will depend on patient body habitus – a setting of8 to 15 cm will suffice for most patients. A curved ab-dominal probe is ideal. Use the lowest depth settingthat allows for adequate field of view – this will enablethe best possible image resolution to be attained. Ad-just gain settings so that vascular structures are dark/black and surrounding tissues are not overbright. It isimportant to use an adequate amount of gel to elimi-nate air gaps between the skin and the transducerwhich will degrade image quality.1. Perihepatic Fig 6. Normal perihepatic FASTFig 5. Position for perihepatic FAST Fig 7. Abnormal or positive hepatorenal FASTThe patient is in the supine position (as for all thescanning positions)The operator should stand or sit to the right of the The dark stripe around the kidney indicates the pres-patient and, ideally, scan with the dominant hand. The ence of intrabdominal fluid which, in the context ofultrasound machine should be at eye level or have the trauma, is likely to be blood. One should also considerscreen tilted to minimise reflection. that ascites has an identical appearance and should be considered in the patient with liver disease or right heart failure etc.
FA S T2. Perisplenic 3. PelvicFig 8. Position for perisplenic FAST Fig 10. Position for pelvic FASTWith the patient supine, the probe should be placed onthe left posterior axillary line between the 10th and 11th Place the transducer in the midline, slightly above theribs, angled to achieve a view of the spleen and left symphysis pubis.kidney interface. The probe should be aligned with the umbilicus and a view of the bladder and Pouch of Douglas or rec- tovesical pouch obtained. Both transverse and longitu- dinal views can be obtained by simply rotating the transducer 90 degrees. As the most dependant part of the lower abdomen, fluid will often collect here before other areas. It has been described as the most sensitive of the four views in the FAST examination.Fig 9. Positive perisplenic FASTIn this scan there is a collection of fluid at the poste-rior aspect of the spleen (arrow). The left kidney isdisplaced inferiorly. Fig 11. Positive pelvic FAST in a female In this scan there is free fluid posterior to the bladder in the pouch of Douglas. The uterus is displaced pos- teriorly.
FA S T4. Pericardial Fig 14. Normal pericardial FASTFig 12. Position for pericardial FASTPlace the transducer under the xiphisternum in themidline, and angle the probe slightly upward towardthe left shoulder until a view of the heart and rightlobe of liver is obtained. Ask the patient to bend hisknees if able. This view is essentially the subcostalwindow used in transthoracic echocardiography, and isvery useful for detecting the presence of pericardialfluid. Fig 15. Positive pericardial FAST In this positive scan, the hypoechoic crescenteric areas anterior to the right ventricle and posterior to the left ventricle represent pericardial fluid. Normally, the right ventricle closely abuts the liver and moves with respira- tion. In the hands of an experienced echocardiographer, the subcostal window is also extremely useful for evaluat- ing cardiac contractility and volume status, detecting cardiac injury and valve dysfunction. However, within the description of the FAST examination, this viewFig 13. Normal subcostal echocardiographic view and should be limited to the detection of pericardial fluidanatomy alone. Pericardial fluid may represent blood from cardiac or aortic injury, but it may also represent an effusion from malignancy, infection, inflammation etc. Care must be
FA S Ttaken to interpret the findings in the context of thepatient’s history. Pericardial tamponade indicates a se-vere life-threatening situation mandating pericardiocen-tesis and/or thoracotomy. The echocardiographic di-agnosis of tamponade, particularly after cardiac sur-gery, is difficult and beyond the scope of this tutorial.However, when there is tamponade physiology (lowcardiac output, hypotension and high venous pressures)and demonstrable pericardial fluid in the trauma pa-tient, tamponade and therefore thoracic injury can beassumed.3. Indications for FASTMany modern evidence-based trauma protocols haveincluded FAST examination as a pivotal axis in the de-cision to go to laparotomy in the unstable patient.There is also literature favouring the use of ultrasoundin stable patients, in penetrating trauma, in chest Fig 17. Algorithm for blunt abdominal trauma - stabletrauma and for the detection of peripheral injuries suchas bone fractures. Note that a positive FAST scan in a stable patient should lead to further investigation by CT scan accord- ing to the above protocol. The advantages of FAST over DPL include speed, non-invasiveness, and specificity. The advantages over CT include speed, portability, and ease of repeated scanning. An experienced operator can perform a FAST in less than 5 mins. Disadvantages of FAST include a significant false- negative rate, in part due to early examination when only a small amount of fluid is present and not visual- ised by the scan. Serial examinations and/or DPL are recommended when there is ongoing haemodynamic instability and the initial FAST is negative. Retroperito- neal haemorrhage is a possibility when FAST is nega- tive and there is ongoing shock. Obesity and subcutaneous emphysema may lead toFig 16. Algorithm for blunt abdominal trauma - unsta- technically difficult or indeterminate FAST examina-ble tion – a DPL may be necessary. FAST is poor at localisation and grading of organ in-In the stable patient, many algorithms also include jury – CT has significant advantages in the stable pa-FAST as a screening tool for intra-abdominal haemor- tient.rhage
FA S TSummary of FAST vs CT vs DPL 5. References and images Fig 1Speed FAST>DPL>CT www.liv.ac.uk/HumanAnatomy/phd/mbchb/travel/surface1.html Dr P Dangerfield, University of LiverpoolSensitivity DPL>CT and FAST Figs 2,3 Meschan I. 1955 An Atlas of Normal Radiographic Anatomy Saunders, LondonSpecificity CT>FAST>DPL Figs 4,5,6,7,8,10,12,16,17 www.trauma.orgLocalisation CT>FAST>DPL Dr Ng A. FAST examinationEase/portability FAST>DPL>CT Fig 13 http://info.med.yale.edu/intmed/cardio/echo_atlas/views/subcoSafety FAST>CT>DPL stal.html Yale Atlas of Echocardiography, Yale UniversityCost DPL<FAST<CT Other figures www.sonosite.com www.medical.philips.com.au4. Evidence The FAST examination : The standard sonographic views Sisley et al. J Trauma 1998;44:291-7In 3 studies, as a decision making tool for the need forlaparotomy in hypotensive patients (BP<90 sys), FAST Wherret LJ, Boulanger BR, McLellan BA et al. Hypotension afterhad a sensitivity of 100%, specificity of 96% and a blunt abdominal trauma: the role of emergent abdominalnegative predictive value of 100% sonography in surgical triage. J Trauma 1996;41:815-820(Wherret et al., Rozycki et al., McKenny et al.) Rozycki GS, Ballard RB, Feliciano DV et al. Surgeon-performedIn the detection of free intra-abdominal fluid when ultrasound for the assessment of truncal injuries: lessons learnedcompared to a reference standard such as DPL/CT or from 1540 patients. Ann Surg 1998;228:557-567laparotomy, FAST had a sensitivity of 75%, a specific- McKenny MG, Martin L, Lentz K et al. 1000 consecutive ultra-ity of 98% and a negative predictive value of 98% sounds for blunt abdominal trauma. J Trauma 1996;40:607-612(18 studies, 6324 patients, 1992 to 2000) Scalea TM, Rodriguez A, Chiu WC et al. FAST Consensus Con-The minimum amount of fluid that can be detected is ference Committee. Focused Assessment with Sonography for70 – 250mls depending on the study (Jehle et al., Trauma (FAST): Results from an International Consensus Confer-Chambers et al., Goldberg et al.) ence. J Trauma 1999;46:466-472Minimum standards for training have been released by Rozycki GS, Shackford SR. Ultrasound, what every trauma sur-many groups. The number of scans for official verifica- geon should know. J Trauma. 1996;40:1-4tion programs can be greater than 300 in some centres,but a minimum of 25 scans should be gained before Shackford SR, Rogers FB, Osler TM et al. Focused abdominal sonogram for trauma: the learning curve of nonradiologist clini-“flying solo”. A recent study of surgeons who under- cians in detecting hemoperitoneum. J Trauma 1999;46:553-562went an 8 hour training program attained an accuracyrate of 90% in their FAST examinations (n=5, 48-250 Godwin S. Introduction to Emergency Ultrasoundexams per surgeon). Interestingly, studies have shown Jacksonville Medicine Mar 1999that the longer the training programme, the better the www.dcmsonline.org/jax-medicine/1999journals/march99/ultrasaccuracy of candidates’ FAST skills. ound.pdf Baker MJ. Trauma Ultrasound www.sitemaker.umich.edu/emergus/files/traumaus.pdf
ECH O CA RD I O G RA P H YBedside Limited Echocardiography EchocardiographyThe recent move toward bedside haemodynamic as-sessment by portable ultrasound has led to the devel- Transthoracic (TTE) and transoesophageal echocardiographyopment of an easily applied, easily taught form of (TOE) are powerful diagnostic modalities that have been usedechocardiography that purports to give non-expert by cardiologists successfully for many years. The advent ofechocardiographers the ability to quickly ascertainventricular function, volume status in unstable pa- portable technology has increased the attractiveness of thesetients. Bedside Limited Echocardiography (BLE) or techniques for perioperative use, particularly for cardiac anaes-BLEEP (BLE by Emergency Physicians) is gaining thesia where TOE has found a specialised role.popularity in many units and has been employed byintensivists and anesthesiologists for the rapid as-sessment of unstable patients . This next section of With great power comes great responsibility though, and therethe Ultrasound Workshop aims to give participants a are many recommendations for the training and accreditation ofstarting point for further training in this specialised echocardiography practitioners within the spheres of anaesthesiatechnique. The BLEEP does not in anyway replaceformal TTE or TOE, and training in BLEEP does and ICU, just as there are for cardiology.not qualify an individual in formal echocardiographywhich remains a highly specialised technique It is recommended that expertise in TOE be gained in fel- lowship level training, in an adequately supervised environmentEquipment taught by adequately qualiﬁed instructors. Typically this might be one year in duration. Formal accreditation by examinationA portable ultrasound machine with cardiac meas- such as the NBE PTE exam (Echo boards) should follow.urement software, Pulse Wave, Continuous Wave, andColour Doppler capability as a minimum. An appro- Minimum numbers of supervised TOE procedures have beenpriate low frequency, small footprint probe (e.g 1- recommended - 50 (level 1), 100 (level 2), or 150 (level 3),5MHz square window) is essential as scanning depths and that the status of the practitioner be advanced accordingly.may exceed 16cm. A method of information storageand patient identification is a requisite - internal hard Ongoing education, audit and review of practice is essential.drive, flash card, magneto-optical disk, DVD or di-rect link via ethernet to PC have all been used suc-cessfully. The ability to review exams offline (digitallyor by VHS) is desirable A formal report should beentered in the patient record for future reference -echocardiography is a diagnostic intervention andformal results should be treated as such.MethodThe Bedside Limited Echocardiogram (BLE) con-sists of 2 views of the heart - the parasternal shortaxis view (PSAX) and the subcostal view (SUB). Toachieve the PSAX view, position the patient in asemilateral recumbent position as pictured. Place theprobe on the left sternal edge and and rotate the in-dex marker to the right shoulder. This should givethe long axis view first - once this is attained then Probe position for the parasternal viewsrotate the probe 90 degrees clockwise until the indexmarker points to the left shoulder to give the PSAXview. The long axis view therefore serves as a mark-ing position to achieve the PSAX view.
ECH O CA RD I O G RA P H Y end systolic distance (LVESD) and LV end diastolic distance (LVEDD), which then allow calculation of fractional shortening (FS%) which is the change in LV linear dimension during systole FS% = LVEDD-LVESD LVEDD Normal LVEDD = 3.5-5.8 cm Normal LVESD (end systolic dimension) 2.2-4.0 cm (mean + 2SD), Mean 3.1cm Normal FS% = 28 to 44 % Ejection fraction (EF) can be estimated as 2 x FS% The advantage of this form of quantitative analysis is that it is a standardised repeatable measurement. A less objective method of estimating ventricular function can be performed in the PSAX view by “eyeballing” the ventricles - observing their move- ment and thickening during the cardiac cycle. An ex- perienced observer can estimate whether global LV function is normal, mildly impaired, moderately im- paired, or severely impaired. Regional wall motion abnormalities (RWMAs) can also be seen in the PSAX and graded according to severity, and although not strictly part of the BLE this is used to assess regional myocardial functionParasternal short axis views . M-Mode measurement of LVEDD and LVESD LV filling assessment can be performed subjectively or objectively in the PSAX but it is not strictly in theFor the purposes of the BLE, the PSAX view is used description of the BLEEP.to formally assess ventricular function by quantitativeanalysis - M-Mode ultrasound is used to measure LV
ECH O CA RD I O G RA P H YThe kissing papillary muscle sign occurs when the LVend systolic volume is low and the papillary musclestouch at end-systole. It is a good indication of hypo-volemia when LV end diastolic volume is also re-duced.The second view required in the BLE examination isthe subcostal view which has been described in thechapter on FAST. The probe must be rotated 90 de-grees and angled slightly to achieve a view of the in-ferior vena cave (IVC) as it courses through the liverfrom it’s junction with the right atrium Subcostal View with IVC in long axis A BLE gives therefore valuable information about global LV function and CVP which can be rapidly used by the clinician to assess haemodynamic status. It has been recommended as a tool for the manage- ment of the unstable or hypotensive patient in the emergency room or intensive care unit. The function of the BLE is not to replace formal echocardiography which gives a much greater diag- nostic yield and requires a much greater degree ofProbe position for the subcostal view formal training to perform and interpret. It is rather an aid to clinical examination in the bedside assess-Central venous pressure (CVP) can be estimated by ment of unstable patients, fulfilling the role of ameasuring the diameter of the IVC in the subcostal FAST exam for the heart and circulation.(SUB) view, and eliciting the sniffing sign from aspontaneously breathing patient. This has been well Referencesvalidated by many studies as a means of estimatingright sided filling pressures. Westmead TOE Manual Dr Lenore George Westmead Hospital SydneyThe following table is used for IVC size vs CVP Bedside Limited Echocardiography by the Emergency PhysicianIVC (cm) Sniffing CVP(mmHg) Is Accurate During Evaluation of the Critically Ill Patient - Jay Pershad, MD*,, Sharon Myers, Cindy Plouman, Cindy Rosson, Krista Elam, Jim Wan, PhD and Thomas Chin, MD, FACC,Small <1.5 collapsed 0-5 FACS|| PEDIATRICS 2004-08811.5-2.5 >50% 5-10 Limited Bedside Echocardiography Performed in the MICU-1.5-2.5 <50% 10-15 Roman Melamed, MD*, Steven Hanovich, MD, Robert Shapiro, MD, Mark Sprenkle, MD, Valerie Ulstad, MD and James Leath->2.5 <50% 15-20 erman, MD CHEST 128 (4) : 207S 2005>2.5 + no change > 20dilated hepaticveins