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Abdominal and Renal Trauma
In the United States, approximately 1 in 10,000 children sustain abdominal trauma each year. Approximately 8000 children are hospitalized with liver and/or spleen injury each year, and kidney and pancreatic injury account for an additional 600 and 200 admissions per year, respectively. In 2000, in response to significant variability in the care of children with abdominal trauma, the American Pediatric Surgery Association (APSA) Trauma Committee published guidelines and benchmarks for management of pediatric solid organ injury. These guidelines standardized the management of children with liver and spleen injury, reduced the hospital length of stay, and set goals for successfully nonoperative management (NOM) of certain injuries. Over time, many of the initial recommendations have changed, and newer guidelines have emerged to help guide management. Recent publications have demonstrated an abbreviated period of bed rest and shorter hospitalization are safe. Additionally, guidelines based on hemodynamic status rather than imaging have proven safe and effective. Similarly, renal injury can be managed with no bed rest. The optimal management strategy for serious pancreatic injury remains controversial, but definitive operative management may be advantageous with early diagnosis, whereas NOM is appropriate for less severe injuries.
Resuscitation of the Child With Blunt Abdominal Trauma
The principles of initial management of the injured child are well delineated in the American College of Surgeons (ACS) Advanced Trauma Life Support (ATLS) course material. Essential treatment priorities include management of the airway (A), establishment of adequate breathing (B) or ventilation, and ensuring adequate cardiovascular circulation (C) while addressing hemorrhage quickly and appropriately. An assessment is then done for neurologic disability (D). Once these priorities have been adequately addressed, detailed evaluation of the abdomen proceeds. Shock in children is often manifested by poor perfusion, with hypotension occurring only after very significant blood loss has occurred. In fact, over half of children requiring blood transfusion for shock are not hypotensive. For hemodynamically unstable children with suspected abdominal injury, the initial assessment includes evaluating their response to transfusion. Crystalloid infusion is limited to 20 mL/kg before initiating transfusion. Patients who fail to stabilize, or those who experience recurrent hypotension after blood transfusion, are likely experiencing ongoing hemorrhage and are at high risk of requiring intervention for bleeding. A massive transfusion protocol should be in place at all trauma centers and centers that care for injured children.
Evaluation of Blunt Abdominal Trauma
Shock index (maximum heart rate divided by minimum systolic blood pressure [normal <0.9]) and the pediatric adjusted shock index (SIPA) have a moderate ability to identify children with intra-abdominal injury needing transfusion or other intervention. For SIPA, the cut-off values by age are >1.22 (ages 4–6), >1.0 (ages 7–12), and >0.9 (13 years and older). In a recent study, SIPA was able to identify 93% of children with a grade 3 or higher liver or spleen injury requiring transfusion within the first 24 hours, but was not as sensitive for more minor injuries.
Computed tomography (CT) remains the diagnostic study of choice in evaluating blunt abdominal trauma ( Fig. 16.1 ). Recent studies by the Pediatric Emergency Care Applied Network (PECARN) suggest a selective approach to imaging is safe. For children with a Glasgow Coma Scale (GCS) score of 15, physical examination findings of abdominal pain alone had a 79% sensitivity for the identification of significant intra-abdominal injury, but the sensitivity decreased rapidly for children with a lower GCS. In fact, even for children with a GCS of 14, half of the children with intra-abdominal injuries did not have abdominal pain on examination. The PECARN network suggests CT may be safely omitted if seven criteria are met ( Table 16.1 ). In another recent study, children with a nonmotorized mechanism of injury, normal GCS, and normal age-adjusted shock index were unlikely to have a solid organ injury that required intervention. In contrast, in another review, the physical examination finding of abdominal wall bruising was quite significant, with 19% of these children having an intra-abdominal injury, and 11% having a bowel injury ( Fig. 16.2 ). Abdominal wall bruising appears to warrant serial abdominal examinations regardless of the decision to image.
Table 16.1
The Seven-Element Criteria for Omitting Abdominal Computed Tomography
| PECARN CRITERIA FOR OMITTING ABDOMEN COMPUTED TOMOGRAPHY |
|
|
|
|
|
|
|
GCS, Glasgow Coma Scale; PECARN, Pediatric Emergency Care Applied Research Network.
Many centers use liver transaminases to determine the need for CT scan in patients without other indications for imaging. Thresholds of >100 are often used to guide the use of CT scanning. In a recent retrospective study, aspartate aminotransferase/alanine aminotransferase (AST/ALT) threshold of <400/<200 had a negative predictive value of 96% in predicting the presence of grade III or higher liver injuries. For children who need abdominal CT, intravenous contrast alone is adequate without the need for oral contrast.
Ultrasound (US) in its various forms may be used to evaluate injured children. Focused assessment with sonography for trauma (FAST) is a user-dependent modality and has poor sensitivity and specificity for both free fluid and injury in adults and children in some studies, whereas other studies find it quite useful. Noncontrast US in hemodynamically stable patients does not appear to add clinically important information. In unstable patients, FAST has secured a role in the trauma center as an adjunct to physical examination with its ability to direct therapy when other modalities are not available ( Fig. 16.3 ). FAST also appears to reduce the number of CT scans in some centers.
Contrast-enhanced US (CEUS) using an intravenous contrast agent shows promise in early trials ( Fig. 16.4 ). Although the sensitivity of CEUS for identifying a specific traumatic injury was low in an initial trial, later trials have shown an impressive ability to identify solid organ injury when compared to CT scan. CEUS, however, is not as sensitive in identifying other intra-abdominal injuries such as pancreatic or diaphragmatic injuries.
Liver and Spleen Injury Management
Blunt liver and spleen injury rarely require operative intervention in children. In a 2014 report, Dodgion et al. noted a significant decrease in the frequency of operations for splenic injury in the United States from 20% in 2000 to 12% in 2009 ( Fig. 16.5 ). A recent prospective study by the ATOMAC group suggested an overall NOM failure rate of 8% in solid organ injury, with only 4.4% failing for bleeding (the remainder failed for other associated intra-abdominal injuries). The frequency of failure for isolated solid organ injury failure was even lower at 0% for splenic injury and 3.9% for liver injury. Most published studies, however, show that hospitals never reached the 95% NOM rate benchmark for stable patients set by APSA in 2000. Although some failures may be related to differences in management approach by the type of hospital or provider specialty, concurrent intestinal or pancreatic injury probably also prevented a higher rate of successful NOM. ∗
∗ References 1, 3, 5, 12, 35, 36.
Mortality rates associated with splenic injury decreased from 4.1 down to 2.9% from 2000 to 2009, and mortality associated with liver injury decreased from 6.3 down to 4.4% ( Fig. 16.6 ). Most pediatric trauma deaths in children with blunt abdominal injuries, however, are due to concomitant brain injury and not the liver or spleen injury. When children fail NOM for bleeding, the mortality approaches 25%.
Nonoperative Management Guidelines
Several studies have noted improved resource utilization and higher rates of NOM when management guidelines are used. The APSA guideline published in 2000 applied to only hemodynamically stable patients and recommended hospitalization based on grade of injury. In that guideline, the formula for the duration of hospitalization was calculated as the number of hospital days equal to injury grade + 1 day. Use of the intensive care unit (ICU) was reserved for grade IV or grade V injuries. However, management based on CT injury grade has been challenged, and many centers have adopted the ATOMAC guideline published in 2015 ( Fig. 16.7 ). This guideline was based on the initial work of the group in Arkansas and validated by St. Peter et al. Whereas the initial algorithm was based on stability, the current algorithm is based on a clinical suspicion of recent or ongoing bleeding. Over the decades in which CT scanning became routine, it was clear that many children had high grade injuries to the liver or spleen that were not hemodynamically significant. The 2000 APSA guideline probably leads to hospitalization for longer periods than needed. Several studies have shown an abbreviated period of hospitalization is safe. The ATOMAC guideline was subsequently prospectively studied in a recent multicenter 3-year study. The updated guideline performed well and was able to correctly guide therapy for all children with blunt liver and/or spleen injury stable enough to undergo CT scan.
Failure of Nonoperative Management
As noted previously, failure rates of NOM vary considerably. Several studies have shown hospital type, provider type, presence of a pediatric trauma center within the trauma system, and lack of clinical practice guidelines may play a role in failure rates. However, patient factors are important in guiding care as well. Holmes et al. used a multicenter retrospective review to describe characteristics of children failing NOM, when they fail, and why they fail. Failure was found to be most common in children with the highest grade injuries, children with isolated pancreatic injury, and children with multiple injured intra-abdominal organs. Failure was infrequent, but when children failed NOM, they tended to do so early, with a median time to failure of 3 hours after arrival. In their retrospective study, 76% of failures occurred by 12 hours. The most common reasons for needing an operation were shock or persistent hemorrhage (49%), peritonitis or bowel injury (42%), pancreatic injury (8%), and ruptured diaphragm (1%).
In 2017, the ATOMAC+ group published a prospective study of 1007 children with liver and/or spleen injuries. Of patients who were candidates for initial NOM, 7% required laparotomy or laparoscopy, but only 3% with attempted NOM required operation for bleeding. Operations for reasons other than bleeding included 21 intestinal injuries, 15 hematoma evacuations, washouts, or drain placements, 9 pancreatic injuries, 5 mesenteric injuries, 3 diaphragm injuries, and 2 bladder injuries. Patients who failed were more likely to undergo early blood transfusion within 2.3 hours of injury. For children who failed NOM due to bleeding, the mortality rate was 24% (8 of 34). Contrast extravasation was associated with an increased risk of failure, and the factors identified by Holmes et al. were also confirmed in this study ( Table 16.2 ).
Table 16.2
Risk Factors for Failure of Nonoperative Management of Liver and Spleen Injuries.
| INCREASED RISK OF FAILURE OF NONOPERATIVE MANAGEMENT IN CHILDREN |
| Mechanism of injury other than fall |
| Transport from scene |
| Hypotension in emergency department |
| Tachycardia in emergency department |
| High volumes of crystalloid |
| Transfusion |
| Early transfusion |
| Combined liver and spleen injuries |
| Associated pancreatic injury |
| Associated renal injury |
| Contrast extravasation on computed tomography |
| Earlier transport times |
| NOT ASSOCIATED WITH HIGHER RISK OF FAILURE IN CHILDREN |
| Gender |
| Age |
| Liver versus spleen injury |
Operative Management of Liver and Spleen Bleeding
For splenic hemorrhage, the abdomen is initially packed in all four quadrants. Packs are removed from one quadrant at a time, typically leaving the quadrant(s) most likely to contain the source of bleeding until last. Definitive treatment options for splenic bleeding include packing and waiting, angiography with packing in place, splenorrhaphy, or splenectomy. As NOM has become more successful, fewer than 400 children per year in the United States undergo splenectomy for trauma.
Operative management of liver bleeding can be challenging. The Western Trauma Association guideline for operative management of adult blunt hepatic trauma is useful ( Fig. 16.8 ). In this stepwise approach, the abdomen is packed. If the bleeding stops, the patient undergoes angiography and ICU monitoring. If packing fails to stop the hemorrhage, a Pringle maneuver is performed. If this controls bleeding, the bleeding is most likely from a hepatic artery or a portal vein branch. These are treated with selective vessel ligation and omental packing. However, if the bleeding continues, the patient most likely has an inferior vena cava (IVC) injury and vascular isolation will be necessary for control. A median sternotomy may be needed, and the IVC injury is approached after vascular isolation. Bardes et al. demonstrate their approach in a recently published video.
Length of Stay
The current evidence supports an abbreviated period of bed rest for NOM, with markedly shorter periods of hospitalization than the 2000 APSA guidelines. Solid organ injury rebleeding occurs but is uncommon. When it does occur, it is often outside of the grade + 1 period of hospitalization included in the 2000 APSA guidelines.
Based on multiple prospective studies, stable children who meet specific criteria can be discharged after a brief period of hospitalization, generally after overnight observation. Exceptions include children with multiple intra-abdominal organ injuries and those with abdominal wall bruising. One analysis suggests more than 9000 days of hospitalization may be saved each year in the United States alone with the adoption of an abbreviated bed rest protocol. Further resource conservation may be achievable by limiting the use of the ICU to patients with recent or ongoing bleeding, grade V injuries, or concurrent injuries mandating a higher level of care.
Hemoglobin and Transfusion
Although initial hemoglobin levels appear useful, routine serial hemoglobin rechecks do not appear necessary to identify patients with continued bleeding. In initially stable patients, vital signs and clinical assessment identify patients requiring additional laboratory evaluations or transfusion.
A transfusion threshold of 7 g/dL for children with blunt trauma has been demonstrated to be safe in multiple studies, including several prospective studies on pediatric trauma patients, as well as a randomized controlled trial of critically ill and injured children in the pediatric ICU.
Delayed Bleeding
One of the major concerns about NOM of solid organ injury is the risk of delayed bleeding. For splenic injury, the risk of delayed bleeding has been estimated as high as 0.3%, but is probably less than 0.2% based on clinical experience and the ATOMAC data. Because delayed hemorrhage does occur, appropriate instructions are critical at the time of discharge.
Defining the Need for Operation
For several years, consensus evidence has suggested 40 mL/kg of blood products during the first 24 hours is a breakpoint at which NOM is less likely to be successful. Recent pediatric data from the U.S. military has confirmed 40 mL/kg is a predictor of early and late mortality in children. Additionally, the need for early transfusion, systolic blood pressure less than 50 mmHg, or a recurrent episode of hypotension suggests a higher risk of mortality. Early recurrent hypotension after blood transfusion in a pediatric trauma patient believed to be bleeding from a solid organ injury indicates failure of NOM and requires operation or another intervention such as embolization.
Angioembolization
Successful control of bleeding with angioembolization for children and adolescents with solid organ injury has been reported in several series and is included in the algorithmic management of traumatic injuries in children ( Fig. 16.9 ). Contrast extravasation is seen in approximately 5–15% of children with splenic injury. The majority of children with contrast extravasation, however, do not need angioembolization, and the current role for angioembolization appears to be limited to children who are otherwise failing NOM. In cases of hemobilia (upper gastrointestinal bleeding due to liver injury with bleeding into the bile ducts), angioembolization has been described with good success. Use of angioembolization in managing pseudoaneurysms of the liver or spleen is controversial and probably not necessary for most splenic pseudoaneurysms.
Endoscopic Retrograde Cholangiopancreaticography
Endoscopic retrograde cholangiopancreaticography (ERCP) after liver trauma appears to have a role in identifying and treating children with major bile duct injuries ( Fig. 16.10 ). Stenting across the injured duct may be possible in selective cases. Additionally, other therapeutic interventions include sphincterotomy and stenting of the ampulla to decrease the biliary tract pressure, even if the injury itself cannot be stented. These procedures are often done as an adjunct to percutaneous drainage of a biloma secondary to a traumatic bile duct injury.
Renal Injury
Renal injuries are less common than injuries to the liver or spleen, representing only about one-third as many admissions. The initial management of blunt renal injury is similar to management of liver and spleen injuries, with >97% of cases managed nonoperatively ( Fig. 16.11 ). One exception, however, is that bed rest after blunt renal injury is not required. Omission of mandatory bed rest for stable patients with blunt renal injury appears to result in a shortened hospitalization without an increased risk of bleeding or readmission.
Although NOM of renal injury grades I through III has been well accepted for many years, management of high-grade injuries without operation is now also the norm. In one series reporting operative intervention in children with low-grade renal injuries, the reason for operation was generally for management of other injuries, or for children found to have congenital anomalies. For grade IV and V renal injuries, surgeons have adopted NOM for hemodynamically stable patients with successful outcomes. In a meta-analysis assessing NOM in grade IV renal injuries, 73% of patients were managed with NOM without intervention. At least partial renal preservation was possible in 95% of these patients. LeeVan et al. reported successful NOM for grade IV and V renal injuries in 80–100% of cases.
Risk factors for failure of NOM include injuries involving the renal collecting system, large perinephric hematomas, urinomas greater than 4 cm, lacerations to the anteromedial or medial portion of the kidney, the presence of dissociated renal fragments, and interpolar extravasation. Transcatheter arterial embolization has been advocated as a first step in the management of active renal bleeding to maximally preserve renal parenchyma and function. The primary indication for operative management is persistent hemodynamic instability. Adjunctive procedures such as stenting, percutaneous drainage, and angioembolization may assist in avoiding laparotomy. Late hypertension is uncommon, but occurs transiently in 6% of high-grade (≥III) injuries. A small number of these patients require long-term antihypertensive treatment.
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