Bleeding in children caused by gastrointestinal vascular lesions.

Intestinal vascular malformations in infants and children are rare but must be considered in the differential diagnosis of gastrointestinal bleeding. Many vascular malformation syndromes have associated intestinal lesions. Localization of vascular lesions is essential for successful management. A variety of treatment options including laser photoablation, surgical resection, and other nonoperative therapies have been utilized to treat these disorders.

Observation of splenic trauma: when is a little too much?

A 12-year-old boy was treated conservatively for a grade II splenic laceration. On discharge, he was instructed to avoid contact sports, running, and strenuous physical activity. Thirty-eight days later, after diving off the side of a swimming pool, he had abdominal pain, nausea, and diaphoresis. On admission, he was hemodynamically unstable. Results of a diagnostic lavage showed gross blood. At laparotomy, a fractured spleen was found, and splenectomy was performed. He recovered without complication. This case questions the activity restrictions placed on patients with conservatively managed splenic trauma. Avoidance of only contact sports and heavy exertion may be inadequate.

Follow-up imaging studies in children with splenic injuries.

We undertook a retrospective study of pediatric blunt splenic injuries treated nonoperatively at our institution from 1990 to 1995 (n = 72) to assess the impact of serial computed tomography (CT) scans on the outcome. Median number of studies per child was three. The result showed that the appearance of the splenic injury remained unchanged or improved in 95% of the imaging studies obtained (116 of 122). Only one of five patients with an image suggesting a worsening splenic injury required operative intervention. There were no instances of missed injuries, delayed ruptures, or readmissions. We conclude that serial CT scans have limited follow-up value and should be used selectively.

Tracheal ligation and mechanical ventilation do not improve the antioxidant enzyme status in the lamb model of congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: The antioxidant enzyme (AOE) system is the primary intracellular defense system of the lung against oxygen toxicity. The authors recently demonstrated depressed levels of catalase, glutathione peroxidase, and superoxide dismutase in congenital diaphragmatic hernia (CDH) lambs compared with controls. The aim of this study was to determine whether tracheal ligation (TL) or mechanical ventilation (recently shown to stimulate growth and surfactant metabolism, respectively) could induce an elevation in AOE activity. METHODS: Four nonventilated lambs with surgically created CDH and TL and five CDH lambs ventilated for 4 hours were studied. Lung tissue was analyzed for AOE and the results compared with untreated CDH lambs. RESULTS: Both ventilation and TL failed to elevate AOE activity above that of untreated CDH lambs. CONCLUSIONS: The data provide further evidence that TL does not improve lung metabolism or maturation. Mechanical ventilation, which often involves high oxygen delivery, is a necessary and often beneficial therapeutic modality. In the CDH neonate compromised not only by low baseline levels of the AOE, but also by an inability to induce enzyme synthesis in response to hyperoxia, mechanical ventilation may, by causing lung injury, be contributing to the high morbidity and mortality rate associated with CDH.

Lung physiological and metabolic changes in lambs with congenital diaphragmatic hernia after administration of prenatal maternal corticosteroids.

BACKGROUND/PURPOSE: Improved outcomes of preterm infants born to mothers treated prenatally with corticosteroids have been documented. The authors investigated the role of prenatal maternal corticosteroid therapy in congenital diaphragmatic hernia (CDH). METHODS: Five CDH lambs of ewes given 0.5 mg/kg betamethasone intravenously 24 hours before delivery (single-dose), four CDH lambs of ewes similarly dosed at 48 and 24 hours before delivery (double-dose), five untreated CDH lambs and five control lambs were studied. After 2 hours of ventilation, compliance, arterial oxygen (PO2) and carbon dioxide (pCO2) concentrations were recorded. Lavage protein and phospholipid levels were measured, and lung tissue was analyzed for antioxidant enzyme activity (AOE). RESULTS: No improvement in gas exchange was noted in either treatment group. Significant increases in compliance (P = .02) were noted in the double-dose steroid group, which were different from that of untreated CDH lambs or controls. Minimal changes in AOE activities were seen with steroid administration. CONCLUSIONS: Although the metabolic changes were not significant, the marked improvement in compliance seen in the double-dosed steroid group suggests a potential role for prenatal maternal corticosteroids in CDH. Further timing and dosage studies are warranted in this model.

The approach to common abdominal diagnosis in infants and children.

This article focuses on salient points in the evaluation of abdominal pain in infants and children. Specifically, the authors address appendicitis and abdominal pain associated with either vomiting, constipation, or gastrointestinal bleeding. A discussion of common abdominal masses, urologic, and gynecologic problems, and considerations in the evaluation of immunologically suppressed or neurologically impaired children, and children with recurrent abdominal pain is also presented. The authors establish logical, focused approaches to the initial evaluation and management of abdominal pain and suggest criteria for timely surgical referral.

Contractile properties of intralobar pulmonary arteries and veins in the fetal lamb model of congenital diaphragmatic hernia.

BACKGROUND/PURPOSE: Pulmonary hypertension plays a significant role in the pathophysiology of congenital diaphragmatic hernia (CDH). Although there has been an intensive research effort directed at mediators that may cause pulmonary vasoconstriction, no single agent has been identified. The authors hypothesize that there may be an alteration in the cGMP-nitric oxide (NO) pathway of vasodilatation contributing to the pulmonary hypertension observed in CDH. The purpose of these studies is to begin to elucidate vasoactive properties of pulmonary vessels with particular attention to the cGMP-NO pathway of vasodilatation in fetal lambs with CDH. METHODS: Fourth-generation pulmonary arteries and pulmonary veins were dissected from both right and left lungs of eight, 139-day gestational fetuses with surgically created CDH. Vessels were studied with standard isolated tissue bath techniques. Experiments examined basal release of NO in endothelium-intact PVs and PAs of both right and left lungs by measuring the contractile force of vessels constricted with norepinephrine (NE) in the presence and absence of the nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine (L-NA). Concentration-response curves to the vasodilating agents zaprinast and A23187 were also obtained in vessels contracted by NE. RESULTS: Left and right pulmonary artery responses to NE are enhanced over those of historic controls. Pretreatment of left pulmonary arteries with L-NA enhances the vasoconstrictor response to NE, whereas right PAs show no increased response. Relaxation responses to A23187 and zaprinast, in both left and right pulmonary arteries were not different from control lambs. Relaxation responses of both left and right pulmonary veins to A23187 and zaprinast are blunted compared with controls. This blunting is significantly more in left pulmonary veins than right. Further, right but not left pulmonary veins display enhanced vasoconstrictive response to NE after L-NA pretreatment. CONCLUSIONS: The NO-cGMP pathway of vasodilatation is abnormal in the near term, fetal lamb with CDH. These abnormalities were most apparent in pulmonary veins and may reflect abnormal NOS activity or content between left and right lungs of the fetal lamb with CDH. Pulmonary arteries from CDH lambs have basal and stimulated NO release equal to that of historic controls but appear to be hypersensitive to exogenous vasoconstrictors.

Cervical ECMO cannula placement in infants and children: recommendations for assessment of adequate positioning and function.

BACKGROUND/PURPOSE: Cervical extracorporeal membrane oxygenation (ECMO) cannula position is often difficult to confirm by chest x-ray alone. Malposition requires a second surgery to rectify the problem. Reoperation places the patient at risk for infection, bleeding, or death. This study analyzes indications for cannula repositioning and suggests an alternative standard for intraoperative evaluation of catheter function as it relates to position. METHODS: The authors reviewed charts of 73 patients placed on arterio-venous ECMO through cervical vascular access. Reasons for repositioning of either cannula at the initial surgery or postoperatively were recorded. RESULTS: Of 73 patients, 18 (24.6%) required either arterial cannula or venous cannula repositioning. In 10 (55%) of these patients, cannula malposition was not detected by chest x-ray during the initial cannulation, and they therefore required a second cervical exploration for repositioning. CONCLUSIONS: Chest x-ray is not sensitive in demonstrating malpositioned cervical ECMO cannulae. Two-dimensional ECHO before wound closure, may be a superior, more cost effective means of assessing cannula placement and function than x-ray alone. Confirmation of cannula position and function, before wound closure, would reduce the risks involved with cervical reexploration.

The approach to common abdominal diagnoses in infants and children. Part II.

Part I (August 1998 issue, Pediatric Clinics), discussed appendicitis and common abdominal diagnoses in infants and in children associated with vomiting, as well as special considerations in the evaluation of immunologically suppressed and neurologically impaired pediatric patients. In this article, the authors continue to discuss the evaluation of constipation, gastrointestinal bleeding, common abdominal masses, and recurrent abdominal pain.

Care of the surgical intensive care nursery graduate. The primary care pediatrician's perspective.

Care of the intensive care nursery graduate may be quite challenging. It is important that primary care pediatricians become familiar with the complications unique to surgical patients so that they may properly prepare and educate parents and provide appropriate long-term follow-up for these often complex patients. Maintenance of a close relationship with the pediatric surgeon with an open line of communication regarding the approach to various surgical problems facilitates the effective integration of the intensive care nursery graduate into the primary care pediatrician's practice and provides the foundation for a successful clinical outcome.

Prenatal diagnosis of the fetus with cystic fibrosis and meconium ileus.

The sonographic finding of hyperechoic or dilated fetal bowel raises suspicion of a number of prenatal disorders including meconium ileus (MI), meconium peritonitis, congenital infection, neoplasm, or chromosomal trisomy. These findings may also represent transient normal variants. The following case report details the evaluation of one pregnancy with abnormal intestinal echogenic findings on serial sonograms (US), to demonstrate inherent diagnostic difficulties in such a case. A diagnostic algorithm is presented to aid in the proper use of US and DNA mutation analysis for cystic fibrosis (CF), so that the cause of an abnormal abdominal US can be established earlier and more accurately than suggested by previous management schemes. Earlier fetal diagnosis may help to anticipate postnatal problems associated with CF/MI, and therefore provide more optimal clinical management of the affected fetus.

Tracheal ligation: the dark side of in utero congenital diaphragmatic hernia treatment.

Currently there are two in utero procedures that have been proposed for the treatment of Congenital diaphragmatic hernia (CDH); reduction of the herniated viscera with repair of the diaphragmatic defect (CDH repair) and stimulation of lung growth by ligation of the fetal trachea (CDH + TL). Recent studies have shown that CDH + TL may result in a significant surfactant deficiency. The aim of this study was to compare the postnatal lung function of these two interventions using the fetal lamb model of CDH. CDH was created in 14 lambs at 78 days' gestation. At 110 days, seven lambs had their trachea ligated through a transverse neck incision and seven had repair of their diaphragmatic defect via a left subcostal incision. At term the lambs were instrumented with the umbilical circulation intact, then delivered and ventilated to a standard protocol for 4 hours. Pulmonary hemodynamics and blood gas levels were measured and compared every 30 minutes. Four lambs in the CDH repair group and five lambs in the CDH + TL group survived to be studied. After the initial data were analyzed, a further group of CDH + TL lambs (n = 4) were studied. In this group a replacement dose of surfactant (Infasurf, Ony Inc, Buffalo, NY) was administered. These initial results cast doubt on tracheal ligation as an in utero therapy for CDH, and indicate that the lung produced by this intervention is not physiologically normal as previously thought. However, the function of these lungs can be normalized if the surfactant deficiency is corrected. If this improvement can be maintained and there is recovery of the endogenous surfactant system, then in utero tracheal ligation may become a viable treatment for fetal CDH.

Physiology and pathophysiology of lung development.

Over the past few years, there has been a considerable improvement in our understanding of the normal development of the fetal lung and its regulation. These advances have occurred mostly through increased knowledge of molecular biological mechanisms of growth and differentiation. These advances have also resulted in an improvement in our comprehension of the pathological basis of various pulmonary diseases. As a result of this new and improved knowledge, new and innovative therapeutic modalities are being introduced into clinical practice. The introduction of surfactant therapy into the clinical setting was one such milestone in neonatal respiratory management. Pulmonary surfactant is responsible for stabilising alveoli during normal respiration, thereby preventing atelectasis or alveolar flooding. Disease processes which result in an insufficiency in surfactant, such as respiratory distress syndrome (RDS) or congenital diaphragmatic hernia (CDH), generally carry a very high mortality rate. Exogenous surfactant administration reduces both the mortality and morbidity associated with RDS and its sequelae, and its efficacy in the treatment of CDH is now being evaluated clinically. Moreover, laboratory studies suggest that surfactant therapy may be used in combination with other treatments, such as tracheal occlusion to promote lung growth in CDH, in order to achieve a maximal effect in these complex, multifactorial lung diseases.

Congenital diaphragmatic hernia. A historical review.

Congenital diaphragmatic hernia (CDH) has been described, studied, and treated for over 400 years. A historical perspective is given. Great strides have been made in the care of patients with CDH; however, the mortality rate remains 30% to 60%. Consideration of historical references, observations, and achievements in the study of CDH is important for the continued advancement and improvement in our understanding of and future success in treating infants and children with CDH.

Prenatal diagnosis of congenital diaphragmatic hernia with predictors of mortality.

Since the late 1970s, congenital diaphragmatic hernia (CDH) has been diagnosed antenatally by ultrasound. With improvements in ultrasound resolution, CDH is being diagnosed more frequently and at an earlier stage in gestation. This provides an opportunity to administer in utero therapy to the fetus. As 50% of babies born with CDH survive, it is imperative that accurate prognostic indicators are available to guide antenatal therapy. Antenatal diagnosis and prognostic indicators are discussed.