Reducing Postoperative CT Imaging for Children With Complicated Appendicitis: A Pediatric Surgical Quality Collaborative Quality Improvement Project

BACKGROUND

Despite widespread initiatives to reduce ionizing radiation for appendicitis diagnosis, computed tomography (CT) scanning postoperatively remains common. The Pediatric Surgery Quality Collaborative (PSQC) aimed to identify differences between children's hospitals with high and low postoperative CT usage for complicated appendicitis.

METHODS

Using National Surgery Quality Improvement Program Pediatric data from PSQC children's hospitals, we compared postoperative CT imaging for complicated appendicitis (April 2020-March 2021). Key stakeholders from 11 hospitals (5 low CT utilization, 6 high CT utilization) participated in semi-structured interviews regarding postoperative imaging. Qualitative analysis of transcripts was performed deductively and inductively based on the Theoretical Domains Framework (TDF).

RESULTS

Five of twelve TDF domains were most prominent in influencing CT use: skills, beliefs about capabilities, intentions/goals, memory and decision processes, and environment. Children's hospitals with lower rates of postoperative CT use tended to: trust and educate the ultrasound technicians; believe US strengths outweigh weaknesses; image no sooner than 7 days postoperatively; have access to sufficient quality improvement resources; maintain trusting relationships between specialties; and prioritize radiation stewardship.

CONCLUSION

Hospitals at extremes of postoperative CT use for complicated appendicitis reveal strategies for improvement, which include imaging protocol development and adherence, quality improvement resource availability, interdisciplinary collaboration, and promoting radiation stewardship.

LEVEL OF EVIDENCE

Level V.

Multicenter retrospective comparison of spontaneous intestinal perforation outcomes between primary peritoneal drain and primary laparotomy

PURPOSE

The purpose of our study was to compare outcomes of infants with spontaneous intestinal perforation (SIP) treated with primary peritoneal drain versus primary laparotomy.

METHODS

We performed a multi-institution retrospective review of infants with diagnosis of SIP from 2012 to 2016. Clinical characteristics and outcomes were compared between infants treated with primary peritoneal drain vs infants treated with laparotomy.

RESULTS

We identified 171 patients treated for SIP (drain n = 110 vs. laparotomy n = 61). There were no differences in maternal or prenatal characteristics. There were no clinically significant differences in vital signs, white blood cell or platelet measures, up to 48 h after intervention. Patients who were treated primarily with a drain were more premature (24.9 vs. 27.2 weeks, p < 0.001) and had lower median birth weight (710 g vs. 896 g, p < 0.001). No significant differences were found in complications, time to full feeds, length of stay (LOS) or mortality between the groups. Primary laparotomy group had more procedures (median number 1 vs. 2, p = 0.002). There were 32 (29%) primary drain failures whereby a laparotomy was ultimately needed.

CONCLUSIONS

SIP treated with primary drain is successful in the majority of patients with no significant differences in outcomes when compared to laparotomy with stoma.

THE LEVEL OF EVIDENCE

III.

Inflammatory pseudotumor of the alimentary tract: clinical and surgical experience

BACKGROUND/PURPOSE

Initially described in 1937, inflammatory pseudotumor (IPT) inflammatory myofibroblastic tumor (IMT) or plasma cell granulomas are synonymous for an inflammatory solid tumor that contains spindle cells, myofibroblasts, plasma cells, and histocytes. Common sites of presentation include lung, mesentary, liver, and spleen; intestinal presentations are rare, and the etiology remains obscure. This report details the clinical and surgical experiences in 4 children with alimentary tract IPT at a single institution.

METHODS

A retrospective chart review was conducted of pediatric patients with the pathologic diagnosis of IPT.

RESULTS

Between 1990 and 1999, 4 patients (4 girls, ages 5 to 15 years) were identified with gastrointestinal tract origins of IPT. Symptoms at presentation included anemia (n = 4), intermittent abdominal pain (n = 3), fever (n = 3), weight loss (n = 2), diarrhea (n = 2), dysphagia (n = 1). Two patients had comorbid conditions of juvenile rheumatoid arthritis and mature B cell lymphoma. Three of 4 patients had elevated sedimentation rates. The sites of origin were the gastroesophageal junction, the colon, the rectum, and the appendix, with the referral diagnosis achalasia, perforated appendix, inflammatory bowel disease, and recurrent lymphoma, respectively. All were treated with aggressive surgical resection, and 3 girls have had no recurrences since the initial surgery. One patient had 3 recurrences within 8 months of presentation; she remains disease free 8 years later.

CONCLUSIONS

IPT, although rare in the gastrointestinal tract, mimics more common problems. Successful surgical management is possible even in cases of multiple recurrences.

Intra-abdominal desmoplastic small round cell tumor

BACKGROUND

Intra-abdominal desmoplastic small round cell tumor is a rare malignancy with a predilection for young males. Unique histological and immunocytochemical features distinguish the tumor from other members of the family of small round cell tumors of infancy and childhood. The aggressive nature of tumor spread, relative insensitivity to chemotherapy, and generally incomplete resectability result in a very poor prognosis. The authors report a case of a 39-year-old man with diffuse abdominal and pelvic involvement of intra-abdominal desmoplastic small round cell tumor treated with aggressive chemotherapy and surgery.

METHODS

Computed tomography (CT)-guided biopsy of an omental mass was performed. Histologically, discrete nests of uniform closely packed malignant cells were distributed in a background of focally desmoplastic stroma. Immunocytochemistry demonstrated positivity for epithelial, mesenchymal, and neural markers. On the basis of these unique histological and immunohistochemical characteristics, the diagnosis of desmoplastic small round cell tumor was made. The patient was treated with aggressive neoadjuvant chemotherapy consisting of a high-dose alkylator -based combination regimen, followed by surgery.

RESULTS

The patient had a 10 to 15 percent regression in tumor mass in response to chemotherapy. Laparotomy revealed two large omental masses, another large mass adherent to the left colon and pelvic sidewall, and diaphragmatic, peritoneal and mesenteric studding with small nodules. Complete surgical resection was not possible.

CONCLUSIONS

Intra-abdominal desmoplastic small round cell tumor remains an aggressive malignancy with an extremely poor prognosis. Although some response to chemotherapy may be possible, complete resection is rare, and surgical efforts are generally palliative.

Interruption of hepatic gap junctional communication in the rat during inflammation induced by bacterial lipopolysaccharide

Gap junctional cellular communication is important in the propagation of signals that coordinate hepatic metabolism. Hepatocytes express two different connexin (Cx) genes, Cx32 and Cx26, which encode for the subunit component of gap junction channels. Previous studies have shown that the expression of hepatic Cx32 is reduced during inflammatory conditions. The objective of this study was to evaluate whether this decrease in Cx32 expression results in a decrease in hepatic gap junctional communication. Transfer of the dye Lucifer Yellow between hepatocytes was measured after microinjection of single cells in an isolated perfused liver. Livers were harvested from rats subjected to an inflammatory condition induced by administration of bacterial lipopolysaccharide (LPS). A decrease in gap junctional cellular communication was observed within 6 h of the LPS treatment. This decrease in dye coupling was reversible, because gap junctional communication returned to control levels within 48 h of the LPS injection. The inhibition of hepatic gap junctional communication was associated with the disappearance of Cx32 and Cx26 from the hepatocyte plasma membrane as detected by indirect immunostaining. Cx32 mRNA levels were also reduced during inflammation as previously reported. However, Cx26 mRNA levels were unaffected or even transiently increased after the injection of LPS without significant increase in the polypeptide level. Thus, the down-regulation of Cx32 and Cx26 from the hepatocyte surface is apparently due to a rapid degradation of the polypeptide from the cell surface. We hypothesize that this loss of gap junctional cellular communication within the liver may contribute to the disordered hepatic metabolic that occurs during inflammatory states.

Downregulation of connexin 43 gene expression in rat heart during inflammation. The role of tumour necrosis factor

Gap junctions form channels that mediate the communication between adjacent cells. Alterations in gap junction function and/or expression are believed to contribute to cardiac dysfunction such as those observed in septic patients. The expression of connexin 43 (Cx43), the subunit component of the most abundant cardiac gap junction, was analysed in rat heart during inflammation induced by the administration of bacterial lipopolysaccharide (LPS). Cx43 mRNA levels were found to be dramatically (>50%) and rapidly (2 h) reduced in the heart after injection of LPS (1 mg/kg). To investigate the possible mechanism of the decrease in Cx43 expression during inflammation, the promoter region of this gene was cloned. The basal Cx43 promoter activity was observed within 224-134 bp of the transcriptional initiation site after transfection into a rat myoblast cell-line (H9c2). The Cx43 promoter activity was found to be reduced by incubation of the transfected cells with serum obtained from LPS-treated rats. Moreover, Cx43 promoter activity was also decreased upon incubation with tumour necrosis factor alpha. These results suggest that Cx43 expression in the heart can be modulated by circulating cytokines. These observations may have important implications in the depression of heart function observed in septic patients.

Expression of the connexin 43 gene is increased in the kidneys and the lungs of rats injected with bacterial lipopolysaccharide

At the molecular level, the inflammatory response is characterized by changes in gene expression of various organ systems. One gene by which expression has been observed to be altered in the liver during inflammation is connexin (Cx) 32. Cx genes encode the polypeptide subunits of the hemichannels that comprise gap junctions. In the present study, an increase in the expression of a different Cx gene, Cx43, was observed in the kidney and lung of rats injected with a sublethal dose (1 mg/kg) of bacterial lipolysaccharide (LPS). To elucidate the possible mechanism by which the Cx43 expression is increased during inflammation, the 5' flanking region of the gene was cloned and coupled to a reporter gene (human growth hormone). This construct was transfected into cells of renal origin (NRK), which express Cx43 constitutively. The Cx43 promoter activity was indeed found in the cloned region, which contained 725 base pairs upstream of the transcriptional initiation site of the Cx43 gene. The Cx43 promoter activity was found to be increased by incubation of the transfected cells with serum obtained from LPS-treated rats. Moreover, direct incubation of the transfected cells with LPS or interleukin 1beta, but not with other cytokines, was observed to increase the Cx43 promoter activity. These results suggest the expression of Cx43 after administration of LPS is part of the inflammatory response. Moreover, the expression of this gene seems to be mediated by proinflammatory mediators.

Differential decrease in connexin 32 expression in ischemic and nonischemic regions of rat liver during ischemia/reperfusion

The effect of a localized hepatic injury, regional ischemia/reperfusion, on the expression of connexin 32 (Cx32) was studied. Cx32 is the component of the major hepatic gap junction. Two regions of the injured liver were analyzed: the area directly affected by the ischemic insult (ischemic liver), and the remainder of the organ (nonischemic liver). In the ischemic liver, there were simultaneous reductions in Cx32 mRNA steady-state levels and the encoding polypeptide from the plasma membrane within 1 h of reperfusion. In contrast, Cx32 mRNA steady-state levels were only reduced after 4 h of reperfusion in the nonischemic liver. This reduction of Cx32 mRNA levels was followed by the disappearance of Cx32 on the plasma membrane within 24 h of the insult. Administration of actinomycin D prior to the ischemic insult prevented the reduction in Cx32 mRNA in both ischemic and nonischemic liver regions. Protein synthesis was blocked during the first hour of reperfusion in the ischemic liver but not in the nonischemic liver. To mimic this effect, animals were treated with cycloheximide in absence of the ischemic insult. A reduction in Cx32 mRNA and polypeptide in the liver was observed in cycloheximide treated animals. This finding suggests that the decrease in Cx32 expression in the ischemic, but not in the nonischemic, liver may be due to the inhibition of protein synthesis during ischemia/reperfusion. These observations suggest that an ischemic insult produces a selective deteriorating effect on Cx32 expression in both ischemic and nonischemic liver regions probably through different mechanisms.

Distinct expression of heat shock and acute phase genes during regional hepatic ischemia-reperfusion

The hepatic response to injury is orchestrated by the expression of different gene groups (i.e., heat shock and acute phase). In the present study, the expression of heat shock and acute phase genes was analyzed in the context of a localized injury, regional hepatic ischemia-reperfusion. Left and median liver lobes were subjected to 1 h of ischemia, whereas blood flow was maintained to the remainder of the organ. After the period of ischemia, the organ was reperfused, and samples of the ischemic and nonischemic liver were obtained at different time points during reperfusion. Expression of the heat shock gene, HSP 72, was detected only in the ischemic liver, whereas expression of the acute phase gene, beta-fibrinogen, and the interleukin-6-inducible gene, metallothionein, was maximally induced in the nonischemic liver and attenuated in the ischemic liver. To determine how the heat shock and acute phase responses were reprioritized during stress, expression of beta-fibronogen and HSP 72 was induced simultaneously in the same animal by administration of endotoxin and total body hyperthermia, respectively. Administration of endotoxin did not impede the expression of HSP 72; however, heat shock attenuated, but did not eliminate, the endotoxin-induced expression of beta-fibronogen. These observations suggest that the heat shock and acute phase responses are not mutually exclusive.

Posttranscriptional regulation of connexin 32 expression in liver during acute inflammation

Gap junctions mediate the communication between adjacent cells in tissues. In the liver, connexin 32 (Cx32) subunits make up the predominating gap junctions. The expression of Cx32 gene has been observed to be down-regulated in response to inflammatory states and during liver regeneration. In the present study we attempt to elucidate the molecular mechanisms underlying the down-regulation of the Cx32 expression during acute inflammation. A decrease in the level of Cx32 mRNA in rat liver occurred between 3 and 6 h after intravenous administration of bacterial lipopolysaccharide (LPS), simultaneously with the induction of an acute inflammatory response characterized by an increase in the level for beta-fibrinogen and a reduction of phosphoenolpyruvate carboxykinase mRNA. The reduction in Cx32 steady-state mRNA levels appears to occur at the posttranscriptional level, since the rate of degradation of this message seems to be higher than the rate of transcription of the gene. Degradation of Cx32 mRNA was blocked by the administration of actinomycin D, but not by cycloheximide, prior to injection of LPS. The stabilization of Cx32 message by actinomycin D correlated with the preservation of Cx32 on the cell surface, which otherwise disappears after administration of LPS alone. These results suggest that cellular communication via gap junctions could be regulated at the level of gene expression, by a posttranscriptional mechanism, during acute inflammatory states.

Enhanced nitric oxide synthase activity in portal hypertensive rabbits

Portal hypertension (PHT) is characterized by splanchnic hyperemia caused by a reduction in mesenteric vascular resistance. Mediators of this hyperemia include nitric oxide (NO). This is based on several reports indicating a marked splanchnic hyporesponsiveness in PHT to vaso-constrictor stimuli, both in vitro and in vivo, and a subsequent reversal using specific inhibitors of NO synthase (NOS). The objective of this study was to determine directly if the generation of NO is altered in PHT vasculature. Thus, we compared NOS activity in the hyperemic vasculature of normal rabbits and rabbits with PHT (after undergoing partial portal vein ligation). Nicotinamide adenine dinucleotide phosphate diaphorase staining indicated the presence of NOS within the vascular endothelium. Ca(2+)-dependent NOS activity was significantly increased (P < .05) in PHT particulate fractions from the superior mesenteric artery and thoracic aorta, but not from the portal vein. There was no change in NOS activity within the cytosolic fractions. Arterial wall cyclic guanosine monophosphate (cGMP) levels and plasma nitrite levels were both significantly increased in PHT. These results show enhanced NOS activity in PHT hyperemic vessels concurrent with increased tissue cGMP levels. We conclude that enhanced NO synthesis contributes to the hyperdynamic circulation of PHT.

Hepatic intercellular communication in shock and inflammation

The liver is well recognized as a target for injury during low flow or inflammatory states. Functionally, the result is both metabolic and host defense dysfunction. Although the liver is clearly responsive to changes in systemic levels of various mediators, it is becoming apparent that substantial changes occur within the liver that are not directly dependent on extrahepatic factors. This is the result of complex interactions among the various cell types that exist in a highly organized arrangement within the functional subunit of the liver. The purpose of this review is to summarize the structural relationships which form the basis for this system of cell-cell communication and their functional implications both in the normal liver and during both low-flow and normal-flow inflammatory states.