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The efficacy of focused abdominal sonography for trauma (FAST) as a screening tool in the assessment of injured children
The Efficacy of Focused Abdominal Sonography for Trauma (FAST) as a Screening Tool in the Assessment of Injured Children By Jateen C. Pate1 and J.J. Tepas III Jacksonville, Florida
Purpose: Focused abdominal sonography for trauma (FAST) is rapidly gaining acceptance as an effective and accurate way to determine significant abdominal injury. The authors analyzed their experience in 94 children with blunt torso trauma (BlTT) to assess FAST accuracy in identifying operative lesions and utility in avoiding additional diagnostic studies. Methods:The authors’ pediatric trauma registry was queried to identify all children with BTT who underwent FAST as part of their initial trauma assessment. Accuracy was determined by calculating sensitivity and specificity using as true positives those children with lesions requiring operative intervention. Utility was analyzed by reviewing the need for additional diagnostic or therapeutic intervention in those patients with negative FAST findings and negative clinical examination findings. Results:Three of these 94 children had lesions that required laparotomy. One was FAST positive (sensitivity, 33.3%). One of two FAST-negative patients was a child in extremis from a suspected thoracic aortic disruption, and the other was a
A
BDOMINAL ULTRASONOGRAPHY has long been used in Europe for the initial evaluation of blunt torso trauma (BTT). Focused abdominal sonography for trauma (FAST) performed during the initial resuscitation phase of care is rapidly gaining acceptance in the United States as an effective and accurate way of determining significant abdominal trauma in the injured adult.‘-4 To date, no study has evaluated the role of FAST in determining the actual need for laparotomy in children. We analyzed our experience in 94 children with blunt torso trauma to assess FAST accuracy in identifying operative lesions and utility in avoiding additional diagnostic studies. MATERIALS Focused assessment
From Science
abdominal sonography has been a routine part of the initial of the injured child in our institution since May 1995. We
the Departtnent Centel; Jacksonville,
Presented
at the 29th
of Surgery, Universi& of Florida 655 West Eighth St, Jacksonville, Annual
Surgical Association, Hilton Address reprint requests Surgery, University of Florida. West Eighth St, Jacksonville, Copyright 0 1999 by WB. 0022.3468/99/3401-0009$03.00/O
44
AND METHODS
Meeting
of the American
Health FL. Pediatric
Head, South Carolina, May 10-13, 1998. to J.J. Tepas III. MD, Department of Health Science Centel: Jacksonville. 655 FL 32209. Saunders Company
child with an intestinal disruption in whom peritoneal signs developed 24 hours after injury. Of 89 FAST-negative children, 20 underwent abdominal computed tomography (CT) at the surgeon’s request. Eight of these patients were found to have minor visceral injury that required no further treatment. The remaining 69 included the child with the sot-tic disruption and 68 patients whose hospital course was uneventful and required no additional intervention. Conclusions: From the practical need for operative intervention specificity (95%); however, it (33%). This excellent specificity examination underscores FAST sary diagnostic intervention in study. J Pediatr Surg 34:44-47. Copyright Company. INDEX
WORDS:
Blunt
abdominal
perspective of indicating in BlT, FAST has a high is not particularly sensitive in combination with clinical utility by avoiding unneces72% of the patients in this o 1999 by W.B.
trauma,
focused
Saunders
sonogra-
phv.
identified 94 children with suspected BTT who were evaluated by ultrasonography during the consecutive 26-month period of May 1995 through August 1997. In addition to querying our pediatric trauma registry, medical charts for these children were reviewed for circumstances of injury, clinical examination at time of presentation, results of imaging modalities. medical or surgical treatment, hospital course, and outcome. Portable real-time ultrasonography was performed during the initial resuscitation phase of care on all study patients by a senior in-house radiology resident. With the patient in the supine position, the pericardial space, subhepatic space (Morison’s pouch), splenorenal recess, and retrovesical space were visualized for free intraperitoneal fluid (FIF). FAST patients were evaluated only for the presence or absence of FIF. No attempt was made to evaluate individual organs for injury. In selected patients. at the attending surgeon’s discretion, abdominal computed tomography (CT) was performed. CT data were collected for the presence and site of intraperitoneal fluid; other significant findings, including the presence of solid or visceral organ injury. retroperitoneal hematoma, or pelvic fracture, were recorded. All radiological imaging was interpreted initially by a senior radiology resident, and results were confirmed immediately or within 8 hours by an attending radiologist. FAST accuracy was determined by calculating sensitivity and specificity using as tIue positives those children with lesions requiring operative intervention. Accuracy of clinical examination in evaluable patients was calculated using as true positives those children with clinical findings and confirmed abdominal injuries by CT or laparotomy. Utility was analyzed by reviewing the need for additional diagnostic or therapeutic intervention in those patients with negative FAST findings and negative clinical examination findings. Journal
of Pediatric
Surgery,
Vol34,
No 1 (January),
1999: pp 44-47
EFFICACY
OF FAST IN INJURY
ASSESSMENT
45
RESULTS
Table 2. Distribution
Overall hospital mortality rate in this study population was 13% (12 of 94 children). Ten had a lethal brain injury, one had a fatal aortic transection, and all of these were FAST negative. One FAST-positive child sustained a severe cervical spine injury and an anoxic brain injury. Eighty-two hospital survivors were discharged either to home (67%) or to a physical rehabilitation center (33%). Ninety-four children underwent FAST for suspected BTT. In all patients, the study was performed within a median of 10.5 minutes (mean, 14 minutes) after arrival to our level-l trauma center. There were 44 boys and 50 girls, with a mean age of 11.3 years, and a mean Injury Severity Score of 21. Other clinical characteristics are outlined in Table 1. Motor vehicle-related injuries predominated, occurring in 82 of 94 children: 42 were passengers, 25 were pedestrians, and 15 children were on a bicycle when struck by an automobile. Other causes of injury included fall (5%), motorized terrain vehicle (3%), motorcycle (I%), assault (l%), and other (2%). Associated injuries were common and included head, face, chest, abdomen, and skeletal. Fifty-one children had a significant head injury, defined by Abbreviated Injury Score ~3, and 18 children sustained chest trauma. Orthopedic injuries involving the extremity, spine, and pelvis were seen in 15, 4, and 3 children, respectively. Abdominal injury, identified by CT or laparotomy, was found in 15 children (Table 2). Seventy-five of 94 children (80%) had one or more body regions involved and one third of these had two or more body regions involved. Reliable initial physical examination of the abdomen was possible in only 39 of 94 (41%) children. Of the remaining 55. 41 children sustained a closed head injury, and 14 were without head injury but were unevauable because of either intubation or impaired mental status. Of those who underwent an adequate physical examination, abdominal tenderness was present in 18 children, distension was present in one, and abdominal wall abrasions or ecchymosis was present in three children. Seventeen
of lntraabdominal With
BlT
Injury
in Children
(n = 15)
Injury
Frequency
Spleen Liver
8 7
Kidney Adrenal
3 1
Stomach Aorta
1 1
children had benign abdominal examination findings with regard to tenderness, distension, ecchymosis, or guarding. Accuracy of clinical examination in predicting intraabdominal injury in the evaluable child was therefore 71%, with a sensitivity and specificity of 100% and 6 1% , respectively. Of the five children who were FAST positive, one required laparotomy (sensitivity, 33.3%). This patient remained hemodynamically unstable despite appropriate volume resuscitation in the trauma center and was found to have splenic and liver injury with FIF at exploratory celiotomy. The other four children had confirmed solid organ injury with FIF by computed tomography. All were treated nonoperatively. Eighty-nine children were FAST negative (specificity, 95.6%) and 20 subsequently underwent CT at the surgeon’s request (Fig 1). Ten children had a negative abdominal CT finding and six had minor solid organ injury treated conservatively. Four children had a delayed Suspected
BTT
FAST Negative n=89
FAST Positive II=5
Laparotomy n=2
CT n=19
Nothing Further: n=68
i All FIF positive Table Age W)” M:F ratio Mortality Ultrasonography
1. Clinical
Data for 94 Children 11.3 + 4.0 1:l.l
time
12.8% 13.9 2 10.8 3.2 t 4.2
(min)t
LOS ICU (d) ISS GCS
LOS ICU, length score; GCS, glascow
score. *All means expressed tMean time of arrival
FIF negative Solid organ injury n=2
J
21 + 15.5 IO 2 4.5 5.7 ? 2.9
PTS Abbreviations: injury severity
J FIF positive Solid organ injury n=6
of stay in intensive care unit; ISS, coma score; PTS, pediatric trauma
as mean 2 SD. to time of ultrasound
scan in minutes.
Laparotomy
n=1
Nonoperative Management
v
ll=‘l
Negative CT II=11 Fig 1.
FAST accuracy
in identifying
operative
lesions
and FIF.
PATEL AND TEPAS
46
CT performed the day after injury for persistent abdominal pain and tenderness. Of these, one CT was without findings and two showed solid organ injuries, with FIF in only one child. No further intervention was required. One child with CT evidence of free intraperitoneal air and fluid was found to have a gastric perforation during exploratory celiotomy. The rest of this patient’s hospital course was uneventful, and he was discharged home on postinjury day 8. Of the remaining 69 children who were FAST negative, one child presented in extremis and during operative exploration was found to have a fatal aortic transection. All other FAST-negative children (n = 68) received no additional abdominal imaging studies, and all had an uneventful hospital course. DISCUSSION
Trauma remains the most common cause of death and disability in the pediatric population. Blunt trauma predominates in this age group; penetrating injuries are far less common. Clinical examination alone has been reported to be notoriously unreliable in patients with suspected blunt torso trauma.5-7 Therefore, focus has turned to other modalities, especially noninvasive imaging studies, for the diagnosis and follow-up of BTT. Computed tomography has long been touted as the “gold standard.“8,9 However, ultrasonography, commonly used abroad for many years, has recently begun to gain acceptance in North America as a first-line imaging study. Studies comparing ultrasound examination to CT for suspected abdominal trauma cite comparable accuracy.‘O,” The pediatric literature, however, is limited in this respect, and CT remains the imaging modality of choice among 86% of pediatric surgeons according to a recent survey. l2 There is no doubt that abdominal sonography is fast, safe, and efficacious in evaluating the injured child. Because the majority of pediatric blunt abdominal injuries do not require operative intervention, determining the presence or absence of abdominal injury alone is not sufficient. Predicting the need for laparotomy is a more practical endpoint when evaluating the traumatized abdomen because it identifies children who need treatment. This view is supported by others.13J4 Previous work has established sonography as an accurate tool in identifying intraabdominal injury.r5-l7 These studies, however, rely on a stable patient able to be transported to the radiology suite for a thorough abdominal evaluation. The purpose of our study was to evaluate the efficacy of focused sonography rather than traditional abdominal ultrasonography as a tool in the initial assessment of BTT. Numerous algorithms have been proposed that incorpo-
rated FAST into the diagnostic evaluation of BIT.**J9 The greatest utility of FAST is it’s ability to rapidly identify the source of blood loss in the hemodynamically unstable, multiply injured child. CT should be reserved for the hemodynamically stable child with a positive or equivocal FAST, or a change in clinical examination findings. It is conceivable that a child with a negative FAST result and a negative clinical examination finding may harbor occult, ie, Grade I or II, solid organ injury. Whether this has any clinical impact, however, is unknown, and further studies directly comparing FAST and CT outcomes with need for laparotomy may provide answers. In our hands, FAST demonstrated excellent specificity but lacked sensitivity. Of three children who required laparotomy, only one was FAST positive. The remaining two included one child in extremis and another with persistent clinical findings on examination who demonstrated hollow viscus injury by CT the day after injury. The low sensitivity in this study may in part be attributed to lack of follow-up-focused sonography, which was not routinely performed. Other investigators have recommended serial FAST examinations,13.20-21and this may have improved sensitivity in our study. In addition, the false-negative rate may just be a function of the low prevalence of laparotomy in this study. FAST also lacked sensitivity (38%) in correctly identifying FIF. Nine children demonstrated abdominal injury despite a negative FAST finding. Three of these had delayed CT examinations done the day after injury, and one of these required laparotomy. Of the nine, only five demonstrated a significant amount of FIF. Thus, four children had minimal to no FIF on abdominal CT despite solid organ injury. The fact that solid organ injury is present without peritoneal fluid is not surprising. Taylor and Sivit** found that 37% of children with intraabdominal injury had no evidence of FIF on CT.*” However, the true accuracy of FAST in detecting FIF was not evaluated in this study. Because only a subset of FAST-negative children underwent additional imaging studies, the number of FIF-positive children missed by FAST is unknown. It is noteworthy that all of these children had an unremarkable clinical observation period, indicating the absence of clinically significant pathology. Although clinical examination alone is not sensitive as a diagnostic method to determine significant intraabdominal injury, it is still the essential starting point of an accurate evaluation. Clinical examination and a negative FAST evaluation successfully avoided further abdominal imaging studies in 72% (68 of 94 children). Combined with ultrasonography, only 2 injured children lacked both songraphic and clinical abdominal examination findings.
EFFICACY
OF FAST
IN INJURY
ASSESSMENT
47
Both of these were unevaluable patients secondary to intubation: one child died of a fatal aortic transection, and the other had a solid organ injury that was managed nonoperatively. FAST has gained acceptance as an accurate tool in evaluating suspected BTT and is especially useful in rapidly identifying the source of blood in the multiply
injured child. In this respect, FAST has established utility over CT in the initial resuscitation of the injured child. Our study demonstrates that FAST was specific (95%) but not particularly sensitive (33%) in identifying the need for operative intervention for BTT. This excellent specificity, combined with clinical examination, avoided additional abdominal imaging studies in 72% of children.
REFERENCES 1. Kimura A, Otsuka T: Emergency center evaluation of hemoperitoneum: A prospective
ultrasonography study. J Trauma
in the 3 1:20-
23.1991 2. Ma OJ. Mateer JR, Ogata M. et al: Prospective analysis of a rapid trauma ultrasound examination performed by emergency physicians. J Trauma 38:879-885. 1995 3. Rorycki GS, Ochsner G, Schmidt JA, et al: A prospective study of surgeon-performed ultrasound as the primary adjuvant modality for injured patient assessment. J Trauma 39:492-500, 1995 4. Boulanger BR, McLellan BA, Brenneman FD. et al: Emergent abdominal sonography as a screening test in a new diagnostic algorithm for blunt trauma. J Trauma 40:867-874, 1996 5. Davis JJ, Cohn 1, Nance FC: Diagnosis and management of blunt abdominal trauma. Ann Sug 183:672-678, 1976 6. Mackersie RC. Tiwary AD, Schackford SR. et al: Intra-abdominal injury following blunt trauma. Arch Surg 124:809-813, 1989 7. Riithlin MA, N%f R, Amgwerd M, et al: Ultrasound in blunt abdominal and thoracic trauma. J Trauma 34:488-495, 1993 8. Turrock RR, Sprigg A. Lloyd DA: Computed tomography in the management of blunt abdominal trauma in children. Br J Surg 80:982-984. 1993 9. Taylor GA, Kaufman RA: Commentary: Emergency department sonography in the initial evaluation of blunt abdominal injury in children. Pediatr Radio1 23:161-164. 1993 10. McElveen TS, Collin GR: The role of ultrasonography in blunt abdominal trauma: A prospective study. Am Surgeon 63: 184-188. 1997 11. Liu M, Lee CH, P’eng FK: Prospective comparison of diagnostic peritoneal lavage, computed tomographic scanning, and ultrasonography for the diagnosis of blunt abdominal trauma. J Trauma 35:267-270, 1993
12. Fallat ME, Casale AJ: Practice patterns of pediatric caring for stable patients with traumatic solid organ injury. 43:820-824, 1997
surgeons J Trauma
13. Bode PJ. Niezen RA, van Vugt AB, et al: Abdominal ultrasound as a reliable indicator for conclusive laparotomy in blunt abdominal trauma. J Trauma 34:27-31, 1993 14. Porter RS, Nester BA. Dalsey WC, et al: Use of ultrasound to determine need for laparotomy in trauma patients. Ann Emerg Med 29:323-330,
1997
15. Luks Fl, Lemire A, St.-Vi] D, et al: Blunt abdominal trauma in children: The practical value of ultrasonography. J Trauma 34:607-611. 1993 16. Katz S. Lazar L. Rathaus V, et al: Can ultrasonography replace computed tomography in the initial assessment of children with blunt abdominal trauma? J Pediatr Surg 3 1:649-65 1. 1996 17. Akgiir FM, Aktug T, Olguner M, et al: Prospective study investigating routine usage of ultrasonography as the initial diagnostic modality for the evaluation of children sustaining blunt abdominal trauma. J Trauma 42:626-628. 1997 18. Rossi D. De Goyet J, De Clety S, et al: Management of intraabdominal organ injury following blunt abdominal trauma in children. Int Care Med 19:415-419, 1993 19. Rozycki GS, Feliciano DV. Davis TP: Ultrasound as used in thorocoabdominal trauma. Surg Clin North Am 78:295-3 10, 1998 20. Hoffmann R, Nerlich M, Muggia-Sullam M, et al: Blunt abdominal trauma in cases of multiple trauma evaluated by ultrasonography: A prospective analysis of 291 patients. J Trauma 32:452-458. I992 21. Huang MS, Liu M, Wu JK, et al: Ultrasonography for the evaluation of hemoperitoneum during resuscitation: A simple scoring system. J Trauma 36: 173-177. 1994 22. Taylor GA. Sivit CJ: Posttraumatic peritoneal fluid: Is it a reliable indicator of intraabdominal injury in children? J Pediatr Surg 30:1644-1648, 1995
Purpose: Focused abdominal sonography for trauma (FAST) is rapidly gaining acceptance as an effective and accurate way to determine significant abdominal injury. The authors analyzed their experience in 94 children with blunt torso trauma (BlTT) to assess FAST accuracy in identifying operative lesions and utility in avoiding additional diagnostic studies. Methods:The authors’ pediatric trauma registry was queried to identify all children with BTT who underwent FAST as part of their initial trauma assessment. Accuracy was determined by calculating sensitivity and specificity using as true positives those children with lesions requiring operative intervention. Utility was analyzed by reviewing the need for additional diagnostic or therapeutic intervention in those patients with negative FAST findings and negative clinical examination findings. Results:Three of these 94 children had lesions that required laparotomy. One was FAST positive (sensitivity, 33.3%). One of two FAST-negative patients was a child in extremis from a suspected thoracic aortic disruption, and the other was a
A
BDOMINAL ULTRASONOGRAPHY has long been used in Europe for the initial evaluation of blunt torso trauma (BTT). Focused abdominal sonography for trauma (FAST) performed during the initial resuscitation phase of care is rapidly gaining acceptance in the United States as an effective and accurate way of determining significant abdominal trauma in the injured adult.‘-4 To date, no study has evaluated the role of FAST in determining the actual need for laparotomy in children. We analyzed our experience in 94 children with blunt torso trauma to assess FAST accuracy in identifying operative lesions and utility in avoiding additional diagnostic studies. MATERIALS Focused assessment
From Science
abdominal sonography has been a routine part of the initial of the injured child in our institution since May 1995. We
the Departtnent Centel; Jacksonville,
Presented
at the 29th
of Surgery, Universi& of Florida 655 West Eighth St, Jacksonville, Annual
Surgical Association, Hilton Address reprint requests Surgery, University of Florida. West Eighth St, Jacksonville, Copyright 0 1999 by WB. 0022.3468/99/3401-0009$03.00/O
44
AND METHODS
Meeting
of the American
Health FL. Pediatric
Head, South Carolina, May 10-13, 1998. to J.J. Tepas III. MD, Department of Health Science Centel: Jacksonville. 655 FL 32209. Saunders Company
child with an intestinal disruption in whom peritoneal signs developed 24 hours after injury. Of 89 FAST-negative children, 20 underwent abdominal computed tomography (CT) at the surgeon’s request. Eight of these patients were found to have minor visceral injury that required no further treatment. The remaining 69 included the child with the sot-tic disruption and 68 patients whose hospital course was uneventful and required no additional intervention. Conclusions: From the practical need for operative intervention specificity (95%); however, it (33%). This excellent specificity examination underscores FAST sary diagnostic intervention in study. J Pediatr Surg 34:44-47. Copyright Company. INDEX
WORDS:
Blunt
abdominal
perspective of indicating in BlT, FAST has a high is not particularly sensitive in combination with clinical utility by avoiding unneces72% of the patients in this o 1999 by W.B.
trauma,
focused
Saunders
sonogra-
phv.
identified 94 children with suspected BTT who were evaluated by ultrasonography during the consecutive 26-month period of May 1995 through August 1997. In addition to querying our pediatric trauma registry, medical charts for these children were reviewed for circumstances of injury, clinical examination at time of presentation, results of imaging modalities. medical or surgical treatment, hospital course, and outcome. Portable real-time ultrasonography was performed during the initial resuscitation phase of care on all study patients by a senior in-house radiology resident. With the patient in the supine position, the pericardial space, subhepatic space (Morison’s pouch), splenorenal recess, and retrovesical space were visualized for free intraperitoneal fluid (FIF). FAST patients were evaluated only for the presence or absence of FIF. No attempt was made to evaluate individual organs for injury. In selected patients. at the attending surgeon’s discretion, abdominal computed tomography (CT) was performed. CT data were collected for the presence and site of intraperitoneal fluid; other significant findings, including the presence of solid or visceral organ injury. retroperitoneal hematoma, or pelvic fracture, were recorded. All radiological imaging was interpreted initially by a senior radiology resident, and results were confirmed immediately or within 8 hours by an attending radiologist. FAST accuracy was determined by calculating sensitivity and specificity using as tIue positives those children with lesions requiring operative intervention. Accuracy of clinical examination in evaluable patients was calculated using as true positives those children with clinical findings and confirmed abdominal injuries by CT or laparotomy. Utility was analyzed by reviewing the need for additional diagnostic or therapeutic intervention in those patients with negative FAST findings and negative clinical examination findings. Journal
of Pediatric
Surgery,
Vol34,
No 1 (January),
1999: pp 44-47
EFFICACY
OF FAST IN INJURY
ASSESSMENT
45
RESULTS
Table 2. Distribution
Overall hospital mortality rate in this study population was 13% (12 of 94 children). Ten had a lethal brain injury, one had a fatal aortic transection, and all of these were FAST negative. One FAST-positive child sustained a severe cervical spine injury and an anoxic brain injury. Eighty-two hospital survivors were discharged either to home (67%) or to a physical rehabilitation center (33%). Ninety-four children underwent FAST for suspected BTT. In all patients, the study was performed within a median of 10.5 minutes (mean, 14 minutes) after arrival to our level-l trauma center. There were 44 boys and 50 girls, with a mean age of 11.3 years, and a mean Injury Severity Score of 21. Other clinical characteristics are outlined in Table 1. Motor vehicle-related injuries predominated, occurring in 82 of 94 children: 42 were passengers, 25 were pedestrians, and 15 children were on a bicycle when struck by an automobile. Other causes of injury included fall (5%), motorized terrain vehicle (3%), motorcycle (I%), assault (l%), and other (2%). Associated injuries were common and included head, face, chest, abdomen, and skeletal. Fifty-one children had a significant head injury, defined by Abbreviated Injury Score ~3, and 18 children sustained chest trauma. Orthopedic injuries involving the extremity, spine, and pelvis were seen in 15, 4, and 3 children, respectively. Abdominal injury, identified by CT or laparotomy, was found in 15 children (Table 2). Seventy-five of 94 children (80%) had one or more body regions involved and one third of these had two or more body regions involved. Reliable initial physical examination of the abdomen was possible in only 39 of 94 (41%) children. Of the remaining 55. 41 children sustained a closed head injury, and 14 were without head injury but were unevauable because of either intubation or impaired mental status. Of those who underwent an adequate physical examination, abdominal tenderness was present in 18 children, distension was present in one, and abdominal wall abrasions or ecchymosis was present in three children. Seventeen
of lntraabdominal With
BlT
Injury
in Children
(n = 15)
Injury
Frequency
Spleen Liver
8 7
Kidney Adrenal
3 1
Stomach Aorta
1 1
children had benign abdominal examination findings with regard to tenderness, distension, ecchymosis, or guarding. Accuracy of clinical examination in predicting intraabdominal injury in the evaluable child was therefore 71%, with a sensitivity and specificity of 100% and 6 1% , respectively. Of the five children who were FAST positive, one required laparotomy (sensitivity, 33.3%). This patient remained hemodynamically unstable despite appropriate volume resuscitation in the trauma center and was found to have splenic and liver injury with FIF at exploratory celiotomy. The other four children had confirmed solid organ injury with FIF by computed tomography. All were treated nonoperatively. Eighty-nine children were FAST negative (specificity, 95.6%) and 20 subsequently underwent CT at the surgeon’s request (Fig 1). Ten children had a negative abdominal CT finding and six had minor solid organ injury treated conservatively. Four children had a delayed Suspected
BTT
FAST Negative n=89
FAST Positive II=5
Laparotomy n=2
CT n=19
Nothing Further: n=68
i All FIF positive Table Age W)” M:F ratio Mortality Ultrasonography
1. Clinical
Data for 94 Children 11.3 + 4.0 1:l.l
time
12.8% 13.9 2 10.8 3.2 t 4.2
(min)t
LOS ICU (d) ISS GCS
LOS ICU, length score; GCS, glascow
score. *All means expressed tMean time of arrival
FIF negative Solid organ injury n=2
J
21 + 15.5 IO 2 4.5 5.7 ? 2.9
PTS Abbreviations: injury severity
J FIF positive Solid organ injury n=6
of stay in intensive care unit; ISS, coma score; PTS, pediatric trauma
as mean 2 SD. to time of ultrasound
scan in minutes.
Laparotomy
n=1
Nonoperative Management
v
ll=‘l
Negative CT II=11 Fig 1.
FAST accuracy
in identifying
operative
lesions
and FIF.
PATEL AND TEPAS
46
CT performed the day after injury for persistent abdominal pain and tenderness. Of these, one CT was without findings and two showed solid organ injuries, with FIF in only one child. No further intervention was required. One child with CT evidence of free intraperitoneal air and fluid was found to have a gastric perforation during exploratory celiotomy. The rest of this patient’s hospital course was uneventful, and he was discharged home on postinjury day 8. Of the remaining 69 children who were FAST negative, one child presented in extremis and during operative exploration was found to have a fatal aortic transection. All other FAST-negative children (n = 68) received no additional abdominal imaging studies, and all had an uneventful hospital course. DISCUSSION
Trauma remains the most common cause of death and disability in the pediatric population. Blunt trauma predominates in this age group; penetrating injuries are far less common. Clinical examination alone has been reported to be notoriously unreliable in patients with suspected blunt torso trauma.5-7 Therefore, focus has turned to other modalities, especially noninvasive imaging studies, for the diagnosis and follow-up of BTT. Computed tomography has long been touted as the “gold standard.“8,9 However, ultrasonography, commonly used abroad for many years, has recently begun to gain acceptance in North America as a first-line imaging study. Studies comparing ultrasound examination to CT for suspected abdominal trauma cite comparable accuracy.‘O,” The pediatric literature, however, is limited in this respect, and CT remains the imaging modality of choice among 86% of pediatric surgeons according to a recent survey. l2 There is no doubt that abdominal sonography is fast, safe, and efficacious in evaluating the injured child. Because the majority of pediatric blunt abdominal injuries do not require operative intervention, determining the presence or absence of abdominal injury alone is not sufficient. Predicting the need for laparotomy is a more practical endpoint when evaluating the traumatized abdomen because it identifies children who need treatment. This view is supported by others.13J4 Previous work has established sonography as an accurate tool in identifying intraabdominal injury.r5-l7 These studies, however, rely on a stable patient able to be transported to the radiology suite for a thorough abdominal evaluation. The purpose of our study was to evaluate the efficacy of focused sonography rather than traditional abdominal ultrasonography as a tool in the initial assessment of BTT. Numerous algorithms have been proposed that incorpo-
rated FAST into the diagnostic evaluation of BIT.**J9 The greatest utility of FAST is it’s ability to rapidly identify the source of blood loss in the hemodynamically unstable, multiply injured child. CT should be reserved for the hemodynamically stable child with a positive or equivocal FAST, or a change in clinical examination findings. It is conceivable that a child with a negative FAST result and a negative clinical examination finding may harbor occult, ie, Grade I or II, solid organ injury. Whether this has any clinical impact, however, is unknown, and further studies directly comparing FAST and CT outcomes with need for laparotomy may provide answers. In our hands, FAST demonstrated excellent specificity but lacked sensitivity. Of three children who required laparotomy, only one was FAST positive. The remaining two included one child in extremis and another with persistent clinical findings on examination who demonstrated hollow viscus injury by CT the day after injury. The low sensitivity in this study may in part be attributed to lack of follow-up-focused sonography, which was not routinely performed. Other investigators have recommended serial FAST examinations,13.20-21and this may have improved sensitivity in our study. In addition, the false-negative rate may just be a function of the low prevalence of laparotomy in this study. FAST also lacked sensitivity (38%) in correctly identifying FIF. Nine children demonstrated abdominal injury despite a negative FAST finding. Three of these had delayed CT examinations done the day after injury, and one of these required laparotomy. Of the nine, only five demonstrated a significant amount of FIF. Thus, four children had minimal to no FIF on abdominal CT despite solid organ injury. The fact that solid organ injury is present without peritoneal fluid is not surprising. Taylor and Sivit** found that 37% of children with intraabdominal injury had no evidence of FIF on CT.*” However, the true accuracy of FAST in detecting FIF was not evaluated in this study. Because only a subset of FAST-negative children underwent additional imaging studies, the number of FIF-positive children missed by FAST is unknown. It is noteworthy that all of these children had an unremarkable clinical observation period, indicating the absence of clinically significant pathology. Although clinical examination alone is not sensitive as a diagnostic method to determine significant intraabdominal injury, it is still the essential starting point of an accurate evaluation. Clinical examination and a negative FAST evaluation successfully avoided further abdominal imaging studies in 72% (68 of 94 children). Combined with ultrasonography, only 2 injured children lacked both songraphic and clinical abdominal examination findings.
EFFICACY
OF FAST
IN INJURY
ASSESSMENT
47
Both of these were unevaluable patients secondary to intubation: one child died of a fatal aortic transection, and the other had a solid organ injury that was managed nonoperatively. FAST has gained acceptance as an accurate tool in evaluating suspected BTT and is especially useful in rapidly identifying the source of blood in the multiply
injured child. In this respect, FAST has established utility over CT in the initial resuscitation of the injured child. Our study demonstrates that FAST was specific (95%) but not particularly sensitive (33%) in identifying the need for operative intervention for BTT. This excellent specificity, combined with clinical examination, avoided additional abdominal imaging studies in 72% of children.
REFERENCES 1. Kimura A, Otsuka T: Emergency center evaluation of hemoperitoneum: A prospective
ultrasonography study. J Trauma
in the 3 1:20-
23.1991 2. Ma OJ. Mateer JR, Ogata M. et al: Prospective analysis of a rapid trauma ultrasound examination performed by emergency physicians. J Trauma 38:879-885. 1995 3. Rorycki GS, Ochsner G, Schmidt JA, et al: A prospective study of surgeon-performed ultrasound as the primary adjuvant modality for injured patient assessment. J Trauma 39:492-500, 1995 4. Boulanger BR, McLellan BA, Brenneman FD. et al: Emergent abdominal sonography as a screening test in a new diagnostic algorithm for blunt trauma. J Trauma 40:867-874, 1996 5. Davis JJ, Cohn 1, Nance FC: Diagnosis and management of blunt abdominal trauma. Ann Sug 183:672-678, 1976 6. Mackersie RC. Tiwary AD, Schackford SR. et al: Intra-abdominal injury following blunt trauma. Arch Surg 124:809-813, 1989 7. Riithlin MA, N%f R, Amgwerd M, et al: Ultrasound in blunt abdominal and thoracic trauma. J Trauma 34:488-495, 1993 8. Turrock RR, Sprigg A. Lloyd DA: Computed tomography in the management of blunt abdominal trauma in children. Br J Surg 80:982-984. 1993 9. Taylor GA, Kaufman RA: Commentary: Emergency department sonography in the initial evaluation of blunt abdominal injury in children. Pediatr Radio1 23:161-164. 1993 10. McElveen TS, Collin GR: The role of ultrasonography in blunt abdominal trauma: A prospective study. Am Surgeon 63: 184-188. 1997 11. Liu M, Lee CH, P’eng FK: Prospective comparison of diagnostic peritoneal lavage, computed tomographic scanning, and ultrasonography for the diagnosis of blunt abdominal trauma. J Trauma 35:267-270, 1993
12. Fallat ME, Casale AJ: Practice patterns of pediatric caring for stable patients with traumatic solid organ injury. 43:820-824, 1997
surgeons J Trauma
13. Bode PJ. Niezen RA, van Vugt AB, et al: Abdominal ultrasound as a reliable indicator for conclusive laparotomy in blunt abdominal trauma. J Trauma 34:27-31, 1993 14. Porter RS, Nester BA. Dalsey WC, et al: Use of ultrasound to determine need for laparotomy in trauma patients. Ann Emerg Med 29:323-330,
1997
15. Luks Fl, Lemire A, St.-Vi] D, et al: Blunt abdominal trauma in children: The practical value of ultrasonography. J Trauma 34:607-611. 1993 16. Katz S. Lazar L. Rathaus V, et al: Can ultrasonography replace computed tomography in the initial assessment of children with blunt abdominal trauma? J Pediatr Surg 3 1:649-65 1. 1996 17. Akgiir FM, Aktug T, Olguner M, et al: Prospective study investigating routine usage of ultrasonography as the initial diagnostic modality for the evaluation of children sustaining blunt abdominal trauma. J Trauma 42:626-628. 1997 18. Rossi D. De Goyet J, De Clety S, et al: Management of intraabdominal organ injury following blunt abdominal trauma in children. Int Care Med 19:415-419, 1993 19. Rozycki GS, Feliciano DV. Davis TP: Ultrasound as used in thorocoabdominal trauma. Surg Clin North Am 78:295-3 10, 1998 20. Hoffmann R, Nerlich M, Muggia-Sullam M, et al: Blunt abdominal trauma in cases of multiple trauma evaluated by ultrasonography: A prospective analysis of 291 patients. J Trauma 32:452-458. I992 21. Huang MS, Liu M, Wu JK, et al: Ultrasonography for the evaluation of hemoperitoneum during resuscitation: A simple scoring system. J Trauma 36: 173-177. 1994 22. Taylor GA. Sivit CJ: Posttraumatic peritoneal fluid: Is it a reliable indicator of intraabdominal injury in children? J Pediatr Surg 30:1644-1648, 1995