e1 References 1 Kwong A, Kim WR, Lake JR, et al OPTN/SRTR 2018 Annual Data Report Liver Am J Transplant 2019;20 (suppl 1) 193 299 2 Mogul DB, Luo X, Bowring MG, et al Fifteen year trends in pedi atric[.]
e1 References Kwong A, Kim WR, Lake JR, et al OPTN/SRTR 2018 Annual Data Report: Liver Am J Transplant 2019;20 (suppl 1):193-299 Mogul DB, Luo X, Bowring MG, et al Fifteen-year trends in pediatric liver transplants: Split, whole deceased, and living donor grafts J Pediatr 2018;196:148-153.e2 Perkins JD, Dick AA, Healey PJ, et al New evidence supporting increased use of split liver transplantation Transplantation 2020;104:299-307 Sundaram SS, Mack CL, Feldman AG, Sokol RJ Biliary atresia: Indications and timing of liver transplantation and optimization of pre-transplant care Liver Transpl 2017;23:96-109 Meyers RL, Tiao G, de Ville de Goyet J, et al Hepatoblastoma state of the art: pre-treatment extent of disease, surgical resection guidelines and the role of liver transplantation Curr Opin Pediatr 2014;26:29-36 McAteer JP, Goldin AB, Healey PJ, Gow KW Surgical treatment of primary liver tumors in children: Outcomes analysis of resection and transplantation in the SEER Database Pediatr Transplant 2013;17:744-750 Hsu EK, Horslen SP, Reyes JD Pediatric End-stage liver disease scores as a method of assessing mortality risk or prioritization to transplantability: Let us save the children JAMA Pediatr 2018; 172:1015-1017 Perito ER, Roll G, Dodge JL, et al Split liver transplantation and pediatric waitlist mortality in the United States: Potential for improvement Transplantation 2019;103:552-557 Montenovo MI, Bambha K, Reyes J, et al Living liver donation improves patient and graft survival in the pediatric population Pediatr Transplant 2019;23:e13318 10 McElroy L, Daud A, Davis A, et al A meta-analysis of complications following deceased donor liver transplant Am J Surg 2014;208:605-618 11 McDiarmid SV, Anand R, Martz K, et al A multivariate analysis of pre-, peri-, and post-transplant factors affecting outcome after pediatric liver transplantation Ann Surg 2011;254:145-154 12 Ooi CY, Brandao LR, Zolpys L, et al Thrombotic events after pediatric liver transplantation Pediatr Transplant 2010;14:476-482 13 Elisofon SA, Magee JC, Ng VL, et al Society of Pediatric Liver Transplantation: current registry status 2011-2018 Pediatr Transplant 2020;24:e13605 14 Borst AJ, Sudan DL, Wang LA, et al Bleeding and thrombotic complications of pediatric liver transplant Pediatr Blood Cancer 2018;65:e26955 15 Laurence JM, Sapisochin G, DeAngelis M, et al., Biliary complications in pediatric liver transplantation: Incidence and management over a decade Liver Transpl 2015;21:1082-1090 16 Shepherd RW, Turmelle Y, Nadler M, et al Risk factors for rejection and infection in pediatric liver transplantation Am J Transplant 2008;8:396-403 17 Alcamo AM, Alessi LJ, Vehovic SN, et al Severe sepsis in pediatric liver transplant patients: The emergence of multidrug-resistant organisms Pediatr Crit Care Med 2019;20:e326-e332 18 Flynn E, Huang JY, Hardikar W, et al Antithrombotic management and thrombosis rates in children post-liver transplantation: a case series and literature review Pediatr Transplant 2019;23:e13420 19 Gurnaney HG, Cook-Sather SD, Shaked, A, et al Extubation in the operating room after pediatric liver transplant: A retrospective cohort study Paediatr Anaesth 2018;28:174-178 20 Fullington NM, Cauley RP, Potanos KM, et al Immediate extubation after pediatric liver transplantation: a single-center experience Liver Transpl 2015;21:57-62 21 Bedel AN, Hemmelgarn TS, Kohli R Retrospective review of the incidence of cytomegalovirus infection and disease after liver transplantation in pediatric patients: comparison of prophylactic oral ganciclovir and oral valganciclovir Liver Transpl 2012;18:347-354 22 Blondet NM, Healey PJ, Hsu E Immunosuppression in the pediatric transplant recipient Semin Pediatr Surg 2017;26:193-198 23 Spada M, Petz W, Bertani A, et al Randomized trial of basiliximab induction versus steroid therapy in pediatric liver allograft recipients under tacrolimus immunosuppression Am J Transplant 2006;6: 1913-1921 24 Ng VL, Alonso EM, Bucuvalas JC, et al Health status of children alive 10 years after pediatric liver transplantation performed in the US and Canada: report of the studies of pediatric liver transplantation experience J Pediatr 2012;160:820-826.e3 e2 Abstract: Liver transplantation (LT) has become the standard of care for children with end-stage or metabolic liver disease, acute liver failure, and unresectable liver tumors, with most common indication being biliary atresia Transplant outcomes now exceed 90% patient survival at year, and 80% at years Comprehensive pretransplant evaluation, improved understanding of immunosuppression, and prompt diagnosis and management of posttransplant complications have contributed to improved outcomes Despite expanded transplant options, including deceased donor whole liver, reduced or split liver, and living donor grafts, nearly 5% of children on the waiting list die each year without LT, with the highest mortality rate in young infants Collaborative multidisciplinary care teams expert in critical care, transplant surgery, and medicine continue to advance the optimal care of children requiring liver transplantation Key words: liver transplantation, hepatic transplantation, biliary atresia 98 Acute Abdomen ROBERT SAWIN, REBECCA STARK, AND DERYA CAGLAR The abdomen is both a primary source of disease conditions that require care in the intensive care unit (ICU) and, frequently, a secondary source of additional pathophysiology for children in the ICU being treated for other conditions Anatomic and Physiologic Considerations Peritoneum The peritoneum provides a protective environment for the intraabdominal organs and, because of its marked sensitivity, a valuable window for the examining healthcare provider It is composed of a single layer of mesothelial cells lining the abdominal cavity along the abdominal wall (the parietal peritoneum) and the intraabdominal viscera (the visceral peritoneum) The space between these is the peritoneal cavity Beneath the mesothelium is a submesothelial layer of extracellular matrix, capillaries, and lymphatics.1 The peritoneum’s sensitivity to inflammation, ischemia, and necrosis is mediated by the fluid in the peritoneum that contains macrophages and other leukocytes.2 Thus, with a focus of inflammation anywhere in the peritoneal cavity, these leukocytes release inflammatory mediators, often resulting initially in poorly localized, generalized pain With irritation of the peritoneum associated with early appendicitis, for example, the patient interprets the inflammation as periumbilical pain This is related to the embryologic development along dermatomes As more inflammatory cytokines are secreted throughout the peritoneal cavity, the pain becomes more generalized and will eventually result in spasm of the overlying muscles of the abdominal wall, interpreted by the examiner as guarding Pain in the gastrointestinal (GI) tract is mainly limited to conditions that result in distention of the organ Inflammation or irritation of the mucosa is generally not the cause of pain, except in the stomach However, disease states that result in full-thickness inflammation of the bowel wall can stimulate the visceral peritoneum, inciting the release of leukocytic and tissue macrophage– derived inflammatory mediators, resulting in pain Patients who are receiving immunosuppressive drugs or are in an immunocompromised state have reduced production of these peritoneal inflammatory mediators Consequently, they can have deceptively 1170 • • PEARLS In either case, early recognition of these conditions and the judicious use of medical and surgical intervention can be key to a successful outcome in critically ill children with abdominal disease or injury little pain despite a significant intraabdominal disease As in other parts of the body, ischemia associated with any abdominal condition results in severe pain, often out of proportion to what is detected on physical examination Visceral Blood Flow The regulation of visceral blood flow is a tightly controlled balance of neural, humoral, paracrine, and metabolic factors.3 In the gut, enteral feeding increases the blood flow and the metabolic demands on the intestinal mucosa Some of these effects are directly related to the nutrients in the intestinal lumen, whereas others are dependent on the enteric nervous system and associated reflexes, on GI hormones, and on GI vasoactive mediators, such as adenosine, endothelin-1, and nitric oxide.4 In pathologic states such as sepsis alone or shock—whether from sepsis, hemorrhage, or cardiac failure—visceral blood flow is reduced This can lead to ischemia of the intestinal mucosa and submucosa Even with restoration of blood pressure and cardiac output following treatment of shock, microvascular perfusion of the intestine may remain impaired, resulting in mucosal ischemia and persistent lactate production Such ischemia can lead to altered integrity of the mucosal barriers to bacteria and other pathogens, increasing the entry of endotoxins into the splanchnic venous and lymphatic systems These pathogens can fuel the inflammatory response This finding has fostered the theory of the gut as a central organ of sepsis or multisystem organ failure (see also Chapter 111).5 Whether the translocation of bacteria or endotoxin from gut lumen to splanchnic drainage is the chicken or the egg can be debated Regardless, this perturbation of intestinal blood flow contributes to the pathophysiology of shock and sepsis Other conditions in the intensive care unit (ICU) can affect splanchnic blood flow, especially mechanical ventilation with high inspiratory pressures, high positive end-expiratory pressure (PEEP), or high tidal volumes.6,7 CHAPTER 98 Acute Abdomen Physical Examination of the Abdomen One should always start the examination of the child by assessing vital signs Fever is common in patients presenting with significant abdominal disease, but it may not always present early in the disease process Tachycardia is seen with fever, pain, or anxiety but is also a sensitive indicator of serious underlying illness, often seen in patients with early compensated shock Hypotension may indicate a decompensated patient who needs immediate attention and intervention for likely sepsis The examination of a child’s abdomen should begin with keen observation, patience, and sensitivity to the patient’s fears and the parents’ anxiety One should first notice the child’s position and demeanor Children with peritonitis not move or writhe about the bed, as this only worsens their pain They will remain quite still and avoid movement or any rapid changes in position A child with visceral ischemia that has not progressed to peritonitis may be actively seeking a more comfortable position with multiple positional adjustments The abdomen should initially be evaluated for any skin changes that can give clues to the underlying process Bruises or patterned abrasions and petechiae can indicate trauma with significant underlying organ lacerations or blood loss Seat belt restraints can often leave a significant lesion on a child’s chest and abdomen after a motor vehicle accident and should prompt further evaluation for intraabdominal injury In the absence of reported trauma, the provider must consider nonaccidental trauma in the differential diagnosis, particularly in very young, nonverbal children Grey Turner sign is significant bruising in the flanks, which indicates significant retroperitoneal bruising and is often associated with severe pancreatitis or pancreatic necrosis Bruising around the umbilicus, Cullen sign, is also an indicator of significant intraabdominal bleeding and pancreatic disease Neonates with necrotizing enterocolitis often have skin changes of the abdominal wall ranging from localized or diffuse erythema to a dusky blue or purple discoloration Observation of the patient’s facial expressions is important throughout the physical examination, as young children may not be able to express what they are feeling or simply are too anxious to give clear responses Once the manual examination is to begin, the examiners should make certain that their hands and stethoscope are warm For the verbal child who has localized the pain to a specific portion of the abdomen, the examiners should start the palpation in the opposite quadrant If palpation in one area causes referred pain in a different location (Rovsing sign), this is suggestive of localized peritonitis in the area of pain, classically seen in appendicitis but also seen in other localized abdominal conditions In generalized peritonitis, spasm of the rectus abdominis can be detected regardless of where the source of the inflammation is located When rectus spasm is detected on one side of the abdomen, a comparison to the rectus on the other side is helpful When both are in spasm, it could be a manifestation of guarding by an anxious child; therefore, distraction should be employed Distraction can often be created by engaging in conversation with the verbal child or by using the warmed stethoscope to listen with light pressure over the area of the abdomen in question, followed by gradually increasing the pressure to elicit a response Asking the child to take a deep breath and blow it all the way out while feeling the rectus can overcome the spasm if it is due to voluntary guarding, while a child with peritonitis will fail to relax the rectus spasm Testing for rebound tenderness is valuable only in older children It should be avoided in children younger than adolescence, 1171 as it is too startling and thus has a high false-positive rate Gently shaking the bed, asking the child to cough, or moving the child’s hips from side to side will cause a painful response in conditions with peritonitis and is much less threatening to younger children As mentioned earlier, pain out of proportion to the findings on physical examination in an ICU patient suggests ischemia independent of the location in the body Bowel sounds are highly variable; thus, their assessment is not usually useful in the ICU patient Significant abdominal distention may also indicate considerable underlying illness and can make the physical examination more challenging Differentiation between apparent tenderness from distention and peritonitis requires patience and gentle palpation Assessing the rectus muscles for spasm may facilitate the diagnosis of peritonitis Distention from hepatomegaly or splenomegaly can be due to end-stage liver disease, malignancy, or masses Fluid in the abdomen could indicate significant blood loss requiring immediate attention and resuscitation Ascites with abdominal pain may be an indicator of spontaneous bacterial peritonitis, particularly in patients with end-stage renal or liver disease Medications can interfere with the reliability of the physical examination of the abdomen As mentioned, steroids can blunt an inflammatory response in the peritoneum and lead to decreased pain sensation despite a significant intraabdominal disease process Patients receiving opiates may have a diminished response to painful stimuli; however, significant intraperitoneal pathology can still be ascertained by careful observation and examination Patients who are receiving paralytic drugs are particularly challenging because the rectus abdominis spasm associated with peritonitis may be substantially decreased Observation of the face, heart rate, or blood pressure can still be valuable, especially by comparing these findings during examination to other areas of the body Just as in the nonsedated, non-ICU patient, beginning the examination on another portion of the body gives the examiner a baseline for comparison Laboratory Tests Assessment of possible intraabdominal conditions should include blood and serum tests that measure inflammation, acid-base abnormalities, possible coagulopathy, and those focused on suspected involved organs The leukocyte count and differential, hematocrit, and platelet counts should always be checked for patients with suspected abdominal disease Leukocytosis, especially with an increased percentage of neutrophils or immature forms (bandemia, left shift), should raise concern about an infectious process Neutropenia suggests a more severe infection or a suppression of the patient’s bone marrow from medications or from the infection; such a situation might make clearance of a bacterial infection more difficult Similarly, both an increased and decreased platelet count can indicate an intraabdominal infection Serial declines in the platelet count are particularly suggestive of a continuing inflammatory consumption seen in conditions such necrotizing enterocolitis Hematocrits must be followed in any child in the ICU because they can demonstrate intraabdominal bleeding or hemolysis related to disseminated intravascular coagulopathy (DIC) Other coagulation tests should be considered, especially in children with severe infections or those with liver dysfunction In such situations, the prothrombin time (PT), partial thromboplastin time (PTT), D-dimers, and fibrin split products are helpful to characterize and monitor the coagulopathy C-reactive protein (CRP) is elevated in states of inflammation and/or infection and may be useful for trending the body’s response to therapy 1172 S E C T I O N X Pediatric Critical Care: Gastroenterology and Nutrition Abnormalities of acid-base balance should be monitored regularly in a child hospitalized in the ICU with an abdominal disease process The source of increased acid can either be an overproduction, such as ongoing lactate generation by ischemic bowel, or decreased acid clearance by the liver or kidneys in conditions associated with shock and decreased visceral blood flow Lactate is a sensitive measure of intestinal ischemia, especially when monitored serially for trends.8 Arterial blood samples are more reliable than venous samples in that measurement Hyperlactemia is not specific to intestinal ischemia and can be associated with any tissue necrosis or underperfusion of organs Elevated serum lactate is also associated with a worse prognosis in patients with sepsis, and the normalization of lactate levels after resuscitation is associated with improved prognosis in patients with sepsis.9 Liver function tests, more accurately termed liver injury tests, include transaminases (alanine transaminase [ALT] and aspartate transaminase [AST]), bilirubin, and g-glutamyltransferase (GGT) These can be elevated with trauma to the liver, active hepatic inflammation, hepatic ischemia, or obstruction of the hepatic venous outflow, known as Budd-Chiari syndrome The latter can result in extremely elevated transaminase levels Elevation of the GGT without a significant rise in transaminase suggests a biliary condition such as common bile duct obstruction or cholecystitis Amylase is a valuable diagnostic test for children with abdominal pain or unexplained intraabdominal sepsis, as hyperamylasemia can indicate pancreatitis Elevated amylase is not specific to pancreatic insults—it can be elevated with head trauma, decreased renal clearance, and intestinal obstruction Serum lipase can be an additive test to the assessment of the pancreas It is more specific to the pancreas but can be mildly elevated in intestinal obstruction as well When both amylase and lipase are markedly elevated, pancreatitis is most likely Children with a past history of severe or chronic pancreatitis might not have marked elevations; thus, the level of the enzyme does not always correlate with the severity of the disease Ultrasonography Imaging Options Plain radiographs of the abdomen can be revealing and are portable, relatively inexpensive, involve small amounts of radiation, and require minimal patient movement To be of greatest value, however, the abdominal radiograph should be done with the patient in at least two different positions, such as supine and upright, and ideally lateral decubitus as well Cross-table laterals can also add value These different views facilitate the identification of air-fluid levels suggestive of small-bowel obstruction and the presence of pneumoperitoneum indicating likely visceral perforation Pneumoperitoneum in a patient with high inspiratory pressures on a mechanical ventilator can sometimes be unrelated to abdominal pathology and instead a consequence of air dissecting through mediastinal and diaphragmatic tissue planes Other plain radiograph findings suggestive of intestinal disease include thumbprinting, pneumatosis intestinalis, and portal venous gas The reliability of abdominal examination is subjective, highly variable, and may depend on the experience of the observer, the fluctuating status of the patient, the patient’s medications, the patient’s level of anxiety, and many other factors Consequently, most ICU providers use imaging studies to ascertain whether intraabdominal pathology warrants intervention For reasons of resource efficiency as well as considerations about the potential risks of ionizing radiation and patient comfort/safety, prudence needs to be exercised before ordering expensive and potentially obfuscating imaging studies The following factors should always be evaluated before performing each study: Specifically, what is one looking for—that is, what is the differential diagnosis? How reliably will this study rule in or rule out those diagnoses— that is, what is the specificity and sensitivity of the study? Will the results of this study change the management—that is, will a negative result prompt the termination of a drug regimen or life-supporting technology, and will a positive study necessitate surgical intervention or initiation of a new therapy? Are the risks—such as ionizing radiation, transportation of a heavily medicated or unstable patient from the ICU to the radiology suite, the administration of intravenous (IV) contrast, and so on—offset by the value of the study? Ultrasonography has several advantages over other imaging studies—most notably, its portability, which obviates the need for moving the patient, and its lack of ionizing radiation exposure In addition, the use of Doppler modality permits the assessment of visceral blood flow to kidneys, pelvic organs, and GI tract When the relative positions of the mesenteric vein and artery can be accurately determined, an abnormal orientation suggests an increased risk of malrotation, even without midgut volvulus.10 The presence of a whirlpool sign can be diagnostic of malrotation with midgut volvulus.11 However, neither finding is sensitive enough to exclude the diagnosis of malrotation, necessitating an upper GI contrast study to clearly determine the position of the duodenal-jejunal junction.12 Assessments of gallbladder wall thickening suggestive of acalculous cholecystitis or biliary tree dilation are particularly accurate Intraabdominal and pelvic fluid collections can be identified, making ultrasound useful in the setting of traumatic injury or suspected intraabdominal abscess It can be used as an adjunct to guide fluid drainage either surgically or percutaneously Recently, ultrasonography has gained popularity for its usefulness in assessing for pneumatosis intestinalis, portal venous gas, and bowel wall perfusion, specifically in infants suspected to have necrotizing enterocolitis.13 In experienced hands, studies have shown that ultrasonography is more sensitive than plain films in this regard.14 This can be particularly useful in patients who are critically ill with an unknown but suspected abdominal source of sepsis who are too unstable to transport for computed tomography (CT) imaging (see also Chapter 15) The use of ultrasound is limited in patients with bowel obstruction or severe paralytic ileus, as intestinal distention creates ultrasonic distortion, minimizing the value of this imaging modality Accuracy of images is also highly dependent on having a skilled and experienced technician Abdominal Plain Radiographs Computed Tomography Abdominal CT scans are accurate, fairly rapid, and can be used to guide interventional procedures such as percutaneous biopsies or drainage of intraabdominal fluid collections Except in institutions where CT scans are located in the ICU or those that have mobile CT units, patients must be transported to access imaging with this modality That requirement can be a significant challenge with children who are ventilated or hemodynamically ... differential diagnosis? How reliably will this study rule in or rule out those diagnoses— that is, what is the specificity and sensitivity of the study? Will the results of this study change the management—that... experienced hands, studies have shown that ultrasonography is more sensitive than plain films in this regard.14 This can be particularly useful in patients who are critically ill with an unknown but suspected... alone or shock—whether from sepsis, hemorrhage, or cardiac failure—visceral blood flow is reduced This can lead to ischemia of the intestinal mucosa and submucosa Even with restoration of blood