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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.

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.

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.

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.

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.

Congenital diaphragmatic hernia carries a high mortality which is often the consequence of associated anomalies. A chromosomal abnormality of the long arm of chromosome 8 resulted in a fatal combination of anomalies associated with CDH.

After birth, the normal umbilicus is a relatively simple structure. During the development of the embryo, however, this region is highly complex. Vestigial of the umbilical cord can be responsible for umbilical inflammation and drainage. This article reviews the embryology of the umbilicus and discusses a number of clinical problems seen in this area. The authors' aim is to aid the primary care pediatrician in evaluating, treating, and appropriately referring umbilical problems encountered in office practice.

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.

Hernias and hydroceles are common conditions of infancy and childhood, and inguinal hernia repair is one of the most frequently performed pediatric surgical operations. As a result of improved neonatal intensive care, more and more premature babies are being delivered, and consequently the incidence of neonatal inguinal hernia is increasing. The most important aspect of the management of neonatal inguinal hernias relate to its risk on incarceration, and emphasis is placed on this point. This article covers the embryology, incidence, clinical presentation, and treatment of groin hernias and hydroceles, as well as dealing with abdominal wall hernias other than umbilical hernias. This article places special emphasis on when a patient with a hernia or hydrocele should be referred to a pediatric surgeon.

The fluid management of the pediatric surgical patient is a crucial aspect of surgical care. This article reviews the fundamental physiology of fluid replacement in children and highlights how standard formulas for fluid therapy can be modified to account for the rapidly changing physiology of the pediatric surgical patient. Novel approaches to fluid treatment of the surgical patient with oral rehydration formulas are discussed. Finally, guidelines for specific management of common pediatric surgical diseases are presented.

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.

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.

Purpose: The regional pediatric trauma center in Buffalo, NY, has been active in pediatric injury prevention programs, including community education and distribution of bicycle helmets, since 1990. Since June 1, 1994, the use of bicycle safety helmets for children under 14 years of age has been mandated by a state law in New York. The authors undertook this study to assess the impact of this legislation on the frequency of helmet use in children involved in bicycle crashes presenting to the regional pediatric trauma center, and to assess the impact of helmet use on the number and severity of head injuries., Methods: Bicycle crash victims (n = 208) admitted to a regional pediatric trauma center from 1993 to 1995 were studied retrospectively. Head injuries were classified as concussion alone, skull fractures, intracranial hemorrhages (ie, epidural, subdural, and subarachnoid), cerebral contusions, or diffuse cerebral edema alone (without any other intracranial injury). Helmeted children (HC) were compared with nonhelmeted children (NHC) using chi2 and Fisher's Exact test. P value less than .05 was considered significant., Results: Only 31 children (15%) wore helmets at the time of the crash. Helmet use increased from 2%, during the period of education alone, to 26% after the legislation went into effect (P < .00001). The proportion of children suffering head injuries was similar in both groups (HC, 68%; NHC, 61%; P = NS). However, the type of head injury was different. HC were more likely to sustain concussion alone (HC, 65%; NHC, 44%; P < .03). HC were less likely to have skull fractures (HC, 0%; NHC, 13%; P < .02), and exhibited a trend toward less intracranial hemorrhages (HC, 0%; NHC, 9%; P = NS), cerebral contusions (HC, 3%; NHC, 5%; P = NS), and cerebral edema (HC, 0%; NHC, 0.6%; P = NS). Excluding the isolated concussions, head injuries were noted in only one HC, compared with 30 NHC (P < .04). None of the three children who died wore helmets at the time of the crash, and all died of multiple head injuries., Conclusions: The bicycle helmet safety law resulted in a 13-fold increase in the use of bicycle helmets among the children admitted to a regional pediatric trauma center after bicycle crashes, but the helmet use remains inadequate. Helmet use reduced the severity of head injuries, and might have prevented deaths caused by head injuries.

Pulmonary hypoplasia and pulmonary hypertension are factors limiting the survival of infants with congenital diaphragmatic hernia (CDH). A reduction in the number of pre-acinar pulmonary vessels and increased muscularization are the structural lesions implicated as causes of irreversible hypoxemia. Whether there is a reduction in the number of air-blood barriers, which represent the capillary surface area of the lung involved in gas exchange, is unknown. We sought to determine if the lungs of CDH lambs have: (1) a reduction in total capillary surface area proportionate to the reduction in the total alveolar surface area of the lung; and/or (2) a disproportionate reduction in the number of capillaries (air blood barriers) within each acinus. The latter measurement was determined by calculating the capillary load which we defined as the number of air blood barriers/unit of surface density. At 80 d gestation (pseudoglandular period), a diaphragmatic hernia was created surgically in one lamb fetus of a twin gestation. At term, the fetuses were removed, the chests opened and the lungs fixed by a tracheal infusion of 1.5% glutaraldehyde at 25 cm of water pressure. Tissues from the lower lobes were examined by light and electron microscopy. Using computerized interactive morphometry, alveolar and capillary surface area, and capillary load were determined by intersection and point counting for the right and left lungs. The data show that the total alveolar surface area of the left CDH and control lungs were 1.8 +/- 0.8 m2 and 6.1 +/- 1.1 m2 (p < 0.01), respectively, and for the right CDH and control lungs 2.5 m2 +/- 0.1 and 11.2 +/- 1.9 m2 (p < 0.01), respectively. The total capillary surface area for the left CDH and control lungs were 0.7 +/- 0.3 m2 and 2.8 +/- 1.2 m2 (p < 0.05), respectively, and for the right CDH and control lungs 0.9 +/- 0.3 m2 and 3.8 +/- 1.5 m2 (p < 0.05), respectively. The capillary load was not statistically different. These findings demonstrate that the lungs in CDH are deficiently vascularized at the alveolar surface due to a reduction in the total alveolar surface area. Each acinus contains the same number of air blood barriers per unit of alveolar surface area indicating a normal acinar composition.

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.

Purpose: In congenital diaphragmatic hernia (CDH) there is immature lung development with a resulting clinical picture of pulmonary hypoplasia, surfactant deficiency, and pulmonary hypertension. Pulmonary hypoplasia and surfactant deficiency both have been successfully treated using partial liquid ventilation (PLV). Pulmonary hypertension associated with CDH has proven difficult to treat, but inhaled nitric oxide, which is a potent highly selective pulmonary vasodilator, may have potential. The aim of this study was to assess PLV in CDH and to document the effect of nitric oxide when administered through perfluorocarbon., Methods: This study using the lamb CDH model consisted of two groups; a conventional mechanically ventilated (CMV) group and a PLV group. At 1 and 3 hours, nitric oxide (80 ppm) was given for 15 minutes. Data collected included blood gases, pulmonary function tests, pulmonary and systemic blood pressure., Results: After 30 minutes of ventilation, blood gases in the PLV group were all significantly improved (P < .001): pH, CMV 6.92 +/- 0.15 versus PLV 7.24 +/- 0.11; P(CO2), CMV 139 +/- 26 mmHg versus PLV 52 +/- 11 mmHg; P(O2), CMV 26 +/- 15 mmHg versus PLV 184 +/- 60 mmHg. In addition, there was a significant increase in dynamic compliance and a reduction in pulmonary hypertension. Nitric oxide was only efficacious in the PLV group, causing a further increase in oxygenation and a decrease in pulmonary hypertension. These effects were reversed when the nitric oxide was stopped., Conclusion: This study shows that PLV both improves gas exchange and pulmonary mechanics in CDH and allows the effective delivery of nitric oxide to reduce the pulmonary hypertension associated with CDH.

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.

Laboratory evidence has recently confirmed clinical reports suggesting that the surfactant system is abnormal in congenital diaphragmatic hernia (CDH). Autopsy series show that, although both lungs are affected by the maldevelopment, the ipsilateral lung is more severely affected. The aim of this study was to examine the surfactant status in each lung in a lamb model of CDH. The lamb CDH model was created on the left side at 80 d of gestation and delivered near term. Subsequently, the lungs were removed and separated from each other. Bronchoalveolar lavage and type II pneumocyte isolations were performed on each side separately. Lavage analyses showed decreased phospholipid (0.12 versus 0.42 mg/g), per cent phosphatidylcholine (51% versus 79%) surfactant-associated protein A (0.20 versus 2.68 mg/g), and surfactant-associated protein-B (0.35 versus 2.21 mg/g) in CDH lungs compared with control lungs. However, no differences were seen between the ipsilateral and contralateral lungs of either CDH or control groups. This was in contrast to the phosphatidylcholine biosynthetic abilities of type II cells isolated from CDH lungs, which were not only lower than those from control lungs (0.15 versus 0.40 nmol/10(6) cells/h), but were also significantly worse in the ipsilateral CDH lung compared with the contralateral CDH lung (0.10 versus 0.20 nmol/10(6) cells/h). Further studies utilizing radiolabeled exogenous surfactant injected in the lower contralateral lung indicate that discrepancies between the presence of type II cell function differences between lungs, and the lack of biochemical differences between the two lungs in CDH, may be due to in utero mixing of lung fluid.

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.

Cardiac evaluation is an important part of the investigation of a fetus with a diaphragmatic hernia. The heart is displaced by the physical presence of the abdominal contents in the chest, and the flow dynamics within the heart are altered. This can produce secondary diminution of chamber growth, particularly of the left heart. Structural heart malformation is also a frequently associated finding. Evaluation of cardiovascular flow profiles may give us further understanding of the pathophysiology of this lesion and may help to predict those fetuses that might benefit from intrauterine therapy.

Congenital diaphragmatic hernia results in abnormal lung development. There is a global hypoplasia with both lungs affected, the ipsilateral lung more severely. This results in a reduction in the number of bronchial divisions and a decrease in the quantity and maturity of the alveoli. The pneumocytes are dysfunctional, resulting in a total quantitative and qualitative reduction in surfactant and a decrease in antioxidant enzyme activity.

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.

Persistent pulmonary hypertension poses a significant problem to the surgeon managing an infant with congenital diaphragmatic hernia. It is likely that a number of abnormalities contribute to this pathophysiologic entity. These include: (1) in the hypoplastic lung the overall cross-sectional area of the pulmonary vascular bed is reduced, (2) the muscular arteries are hypertrophied and extend more peripherally than normal, (3) the pulmonary vessels are more labile than normal and are overly sensitive to the normal stimuli of vasoconstriction, and (4) the immature surfactant-deficient lung is predisposed to barotrauma and atelectasis, resulting in alveolar hypoxemia which contributes to pulmonary hypertension. All of these interfere with the ability of the lung to accept the increase in pulmonary blood flow required by the transitional circulation. If this impairment reaches a level such that the lung cannot accept the right ventricular output then pulmonary hypertension will ensue and a poor outcome can be anticipated.

The first animal model of congenital diaphragmatic hernia (CDH) was described in 1967. This was a late-gestational, surgically-created lamb model. Since then, animal modeling has become more sophisticated. Using a variety of techniques and laboratory species, animal models have been produced to investigate the pathophysiology of CDH, from whole animal physiology studies to lung molecular changes. To provide the animal tissue required, three different approaches have been used: (1) a surgically-created model which has been reported in lambs and rabbits, (2) a teratogen-induced model which to date has been described in rats and mice, and (3) a congenital model which is present in a specific pig herd. All animal models are discussed in this article.

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.

The emphasis in postnatal management has shifted from the neonatal surgical emergency approach to strategies designed to deal with pulmonary hypoplasia and the pulmonary vascular abnormalities. There has been extensive experience with alternative ventilation strategies such as ECMO and high frequency ventilation, without there being convincing evidence that these have had a major impact on mortality. Strategies that emphasize the importance of minimizing ongoing lung injury, such as pressure limited (permissive hypercapnia) ventilation and the use of surfactant replacement therapy, are beginning to show some encouraging results.

Selective left ventricular hypoplasia is a recognized feature of congenital diaphragmatic hernia (CDH). It is speculated that the herniated viscera act as a space occupying lesion that inhibit normal cardiac development. The purpose of this study was to determine the effect of two separate fetal surgical interventions on subsequent cardiac development in CDH. CDH lambs were created at 80 days gestation and underwent either tracheal ligation (CDH + TL) or diaphragmatic repair (CDH + repair) at 110 days gestation. At term (141 days gestation) the hearts were harvested and fixed in 4% paraformaldehyde solution. Anatomic dissections were performed and component heart weights determined. Fresh specimens were analyzed for DNA and protein content. All weights are expressed in grams/kilogram body weight and all data as mean +/- SEM. All measurements are compared to control and CDH tissues. There were seven CDH lambs, five control lambs, five CDH + TL lambs, and five CDH + repair lambs. There were no differences in body weight (kg) between CDH, CDH + TL, CDH + repair, and control littermates. CDH lambs have significantly decreased total heart (4.88 +/- .25* vs 6.75 +/- .49, P < 0.05), left ventricular (1.65 +/- .11* vs 2.15 +/- .19, P < 0.05), septal (1.29 +/- .11* vs 1.99 +/- .21, P < 0.05), and combined atrial (0.68 +/- .06* vs 1.14 +/- .15, P < 0.05) weights (g/kg lamb) without differences in RV weights (1.26 +/- .07 vs 1.57 +/- .17, P = NS) when compared to littermate controls. No differences were found in total heart (4.82 +/- 0.38 vs 4.88 +/- 0.25), left ventricular (1.48 +/- 0.13 vs 1.65 +/- 0.11), septal (1.26 +/- 0.17 vs 1.29 +/- 0.11), combined atrial weights (0.56 +/- 0.07 vs 0.68 +/- 0.06), and right ventricular (1.52 +/- 0.12 vs 1.26 +/- 0.07) between CDH + TL and CDH lambs. There were no differences in total heart (6.60 +/- 0.29 vs 6.75 +/- 0.49), left ventricular (2.10 +/- 0.15 vs 2.15 +/- 0.19), septal (1.97 +/- 0.18 vs 1.99 +/- 0.21), combined atrial (1.10 +/- 0.10 vs 1.14 +/- 0.15), or right ventricular (1.52 +/- 0.12 vs 1.57 +/- 0.17) weights between CDH + repair and control lambs. LV and RV wall thicknesses (cm), as well as total protein and DNA content, and DNA/total protein ratios were identical in all groups. CDH lambs have a significant reduction in total heart weights mainly caused by hypoplasia of the left ventricle (left ventricular "smallness") and the interventricular septum. Removal of the herniated viscera and repair of the diaphragmatic defect correct this abnormality, but tracheal ligation does not. We speculate that although tracheal ligation reverses pulmonary hypoplasia, the enlarging lungs act as space occupying lesions that adversely affect cardiac development. Further investigations are necessary to determine the functional significance of these findings.

Because nitric oxide (NO) dilates vascular smooth muscle cells, a deficiency of endogenous pulmonary nitric oxide production by nitric oxide synthase (NOS) has been suggested to be involved in the pathophysiology of pulmonary hypertension in congenital diaphragmatic hernia (CDH). Our aim was to determine whether experimentally induced CDH in rats results in a decrease in the synthesis of NO in the lungs. Adult Sprague-Dawley rats were fed 300 mg/kg of nitrofen at 10.5 days' gestation. CDH, control, and sham (dosed with nitrofen, but without CDH) lungs were homogenized at full term (22 days' gestation) for measurement of NOS activity using the 14C-L-arginine to 14C-L-citrulline conversion assay. Western blot analysis with anti-endothelial cell NOS (EC-NOS) monoclonal antibody (mAb) was performed, and NOS expression was measured by densitometry. NOS activity was highest in the pulmonary parenchyma of control rat lungs (0.420 +/- 0.20 fmol/min/mg lung; n = 11), intermediate in sham lungs (0.370 +/- 0.010 fmol/min/mg lung; n = 14), and lowest in CDH lungs (0.300 +/- 0.04 fmol/min/mg lung; n = 12). NOS activity in the CDH and sham lungs was significantly lower than that of control lungs (P < .05). There was no difference in pulmonary NOS activity between sham and CDH lungs. NOS protein expression by Western blot analysis paralleled the observation for NOS activity in all groups, with the highest concentrations in controls, intermediate expression in sham lungs, and lowest expression in CDH lungs. Both NOS expression and NOS activity are significantly decreased in CDH rat lungs. Pulmonary hypertension in this model may be attributable to a deficiency of endogenous NO. This is the first reported study to suggest that decreased NOS activity may result in pulmonary hypertension in CDH.

Surfactant therapy given before the onset of ventilation (surfactant prophylaxis) has been shown to improve oxygenation, ventilation, and pulmonary hemodynamics in the lamb model of congenital diaphragmatic hernia (CDH). The aim of this study was to assess the efficacy of surfactant administered after the onset of ventilation ("surfactant rescue"). Ten lambs with surgically created CDH were instrumented, at full term, to measure pulmonary blood flow and pulmonary vascular resistance (PVR). Catheters also were positioned for monitoring of systemic blood pressure and arterial blood gases. The animals were delivered and pressure-ventilated according to a standard protocol (PIP, 30 cm; PEEP, 4 cm; respiratory rate, 60 breaths per minute). After 30 minutes of ventilation, five animals received an intratracheal dose of calf lung surfactant extract (50 mg/kg). The animals were studied for 4 hours. Surfactant rescue had no discernible effect on Pco2, Pco2, or pH. There was an increase in pulmonary blood flow, but it was not significant. The dramatic improvement in oxygenation, ventilation, and pulmonary blood flow found with prophylactic surfactant cannot be reproduced when surfactant is administered as rescue therapy. This indicates that the surfactant is not being delivered adequately, the lungs have already incurred significant barotrauma, and/or the surfactant is being inactivated by alveolar protein. Therefore, the authors suggest that when exogenous surfactant therapy is being considered for the fetus or newborn with CDH, it should be administered as early as possible, preferably before the infant's first breath. Prenatal diagnosis and delivery in a tertiary care center would facilitate this optimum management.

In the pediatric population, there is strong evidence to suggest that a delay in treatment results in an increased risk of appendiceal perforation. However, it is not clear whether this delay arises from the parent seeking medical advice, the referring physician seeking surgical consultation, or the surgeon deciding to operate. To resolve this issue, the authors performed a retrospective chart review of all cases of confirmed acute appendicitis that presented to the pediatric surgical service of the Children's Hospital of Buffalo during a 4-year period (January 1990 through December 1993). All children (< or = 16 years of age) were categorized with respect to type of insurance coverage:Medicaid (or uninsured), health maintenance organization (HMO), or private fee-for-service. Their time until emergency room (ER) presentation, operating room (OR) presentation, and hospital discharge were recorded and compared. Their complications and perforation rates also were noted. Two hundred eighty-eight cases were reviewed. The rate of appendiceal perforation was significantly higher among the Medicaid patients (Medicaid, 44%; HMO, 27%; private, 23%; P < .05); their duration of symptoms before presentation was significantly longer (Medicaid, 47.3 +/- 4.1 hours; HMO, 29.3 +/- 1.9 hours; private, 23.1 +/- 2.5 hours; P < .01), and their hospital stay was longer (Medicaid, 7.9 +/- 0.9 days; HMO, 4.8 +/- 0.27 days; private, 4.6 +/- 0.44 days; P < .01). However, there were no significant differences in the time from presentation to the ER until definitive surgery in the OR. Children covered by Medicaid (or uninsured) presented later, had a higher risk of appendiceal perforation, and required a longer hospital stay. The parents of these children either failed to recognize the significance of their children's symptoms, or delayed seeking medical advice because of financial or logistical reasons. The gatekeeper consultation, required by the health maintenance organizations (HMO) did not result in a delay in presentation or have a negative impact on morbidity. Providing easier access to a primary care physician and improving parental health education/awareness may shorten the time until presentation for the uninsured/Medicaid patient.

Left ventricular disproportion (decreased left-to-right ventricular internal diameter ratio) has been correlated with fetal or neonatal survival in cases of congenital diaphragmatic hernia (CDH). Because cardiac development is intimately related to lung development in the normally developing fetus, the authors sought to determine whether cardiac weight correlates with lung weight in control and CDH lambs at term. Twenty lambs had CDH created surgically at 80 days' gestation and were sacrificed at term for measurement of lung and heart weight. Nine unoperated lambs served as controls. Analysis of the relationship between heart weight and lung weight was performed for both groups, and regression curves were generated as mean +/- 2 standard deviations (SD) for each group of lambs. All data are expressed in grams. For CDH lambs, the relationship between heart and lung weight is as follows: lung weight = 0.69 x heart weight + 37 g. For control lambs, the equation is: lung weight = -0.004 x heart weight + 135 g. There is no overlap of these regression curves at 2 SD of the mean. The curves differ significantly, and the P value exceeds .05. The results suggest that cardiac weight can be used to predict lung weight in CDH and control lambs at term. The authors speculate that this difference in weight is attributable to underdevelopment of the left ventricle in CDH. Given that left ventricular disproportion has been described as early as the pseudoglandular stage of lung development in human fetuses with CDH, it is hoped that echocardiographic parameters can be used to differentiate the fetuses with adequate lung volume from those whose lung volume is incompatible with extrauterine life. Patients in the latter group may benefit from surgical correction of the diaphragmatic defect in utero.

Congenital chylous ascites (CCA) results from maldevelopment of the intra-abdominal lymphatic system. Newborns present with respiratory distress and abdominal distention. Medical treatment of CCA is often prolonged. A newborn with CCA was treated with octreotide, a somatostatin analogue, resulting in rapid and complete resolution of the ascites.

Introduction: Experiments using animal models of neonatal respiratory distress syndrome have shown a decrease in pulmonary vascular resistance (PVR) with surfactant replacement, whereas studies with the lamb model of congenital diaphragmatic hernia (CDH) have demonstrated improvement in oxygenation and lung mechanics with this therapy. The aim of the present study was to measure the effects of surfactant replacement therapy on the pulmonary hemodynamics of the lamb model of CDH., Methods: Ten lambs with surgically created CDH and five control lambs were instrumented at term, with the placental circulation intact. Ultrasonic flow probes were positioned around the main pulmonary artery and the common origin of the left and right pulmonary arteries to record total lung and main pulmonary artery blood flow. Catheters were inserted to record systemic, pulmonary, and left atrial pressure. Five CDH animals received 50 mg/kg of surfactant by tracheal instillation just before delivery. All 15 animals were then ventilated for 4 hours., Results: Correcting the surfactant deficiency in the CDH lamb resulted in a significant increase in pulmonary blood flow, a decrease in PVR, and a reduction in right-to-left shunting. These improvements in hemodynamics were associated with a significant improvement in gas exchange over 4 hours., Conclusion: The fetal lamb model of CDH has elevated PVR in comparison to controls. Prophylactic surfactant therapy reduces this resistance and dramatically increases pulmonary blood flow while reducing extrapulmonary shunt. A surfactant deficiency may be partially responsible for the persistent pulmonary hypertension in neonates with CDH.

Introduction: Experimental tracheal ligation (CDH + TL) has been shown to reverse the profound lung hypoplasia associated with congenital diaphragmatic hernia (CDH) and to normalize gas exchange. The aim of this study was to determine whether this experimental therapy would correct the surfactant deficiency present in the fetal lamb model of CDH., Methods: The CDH lamb model was created at 80 days' gestation, and tracheal ligation was performed at 110 days. At term, the lambs were delivered and were ventilated for 30 minutes. The lambs were killed, a pressure-volume curve performed, and the lungs lavaged to measure total phospholipid content. Finally, type II pneumocytes were isolated, and surfactant synthesis was assessed by the incorporation of tritiated choline into phosphatidylcholine., Results: CDH + TL resulted in a lung significantly larger than that of CDH alone. The lungs of the former also had better oxygenation and ventilation. However, lung compliance was reduced compared with controls. Total alveolar phospholipid was dramatically lower, with a decrease in the proportion of phosphatidylcholine present. Surfactant synthesis by the isolated type II pneumocyte was significantly impaired., Conclusion: Occlusion of the fetal trachea produces a lung comparable in size to a normal control lung. However, broncheoalveolar lavage analysis shows a marked reduction in total phospholipid, with a decrease in surfactant synthesis by the type II pneumocyte. The normalization of gas exchange reported for this animal model may be only a transient phenomenon. Further studies are required to assess the impact of this surfactant deficiency on long-term lung function.

The cardiopulmonary consequences of CDH can be devastating, and despite intensive research the pathophysiologic makeup of this condition is not fully understood. It seems likely that its overall prognosis is related to the size of the pulmonary vascular bed and its capacity to accept the cardiac output at birth. The ability of the lungs to perform this task is impaired by a surfactant deficiency and by pulmonary vessels that respond excessively to normal stimuli of vasoconstriction. Understanding the mechanisms through which these pathophysiological abnormalities are occurring should provide us with therapeutic insights into how we may recruit all the available alveoli in these lungs, prevent ventilation-induced lung injury, optimize pulmonary blood flow, and maximize cardiac output without causing right or left heart compromise. Failure to achieve all or any of these goals can feed back and exacerbate the underlying pathophysiological condition.

Choledochal cyst (CC) is a rare disorder that usually presents in childhood. Prognosis depends on early diagnosis, complete excision of the cyst, and reconstruction by hepaticojejunostomy. This report details our 10-year experience and emphasizes innovations in our management. Sixteen patients presented with CC at a mean age of 3 years. (Range, newborn to 21 years, with a M:F ratio 1:4). Two groups could be identified on the basis of age at presentation. Group I (N = 7), presented in the neonatal period, three with obstructive jaundice and four without symptoms. In Group II (N = 9), all patients presented with ascending cholangitis at a mean age of 6 years. Thirteen patients had a type 1 CC, one patient had a type 3 CC, and two had type 4 CC. The patients with type 1 and type 4 CC underwent primary cyst excision with Roux-en-Y hepaticojejunostomy, whereas the patient with type 3 CC underwent cyst excision with sphincteroplasty of the ampulla. There was only one complication of postop cholangitis that cleared with antibiotic therapy. All patients have remained free from symptoms in the follow-up period (6 months-10 years). Our four most recent cases were diagnosed in utero by prenatal ultrasonography. This led to appropriate antenatal counseling and prospectively planned neonatal surgery. These infants were asymptomatic, with no clinical signs at birth, and antenatal ultrasonography prevented diagnostic delay. Excision of the choledochal cyst and primary hepatico-enteric anastomosis is confirmed as the therapy of choice. Antenatal sonography is a sensitive method in the diagnosis of CC and offers the opportunity for early diagnosis and planned surgery before the onset of complications.

Objectives: To determine the efficacy of perfluorocarbon-associated gas exchange and the effects of inhaled nitric oxide during perfluorocarbon-associated gas exchange in the congenital diaphragmatic hernia lamb model., Design: Prospective, nonrandomized, controlled, nonhuman trial., Setting: Animal research facility., Subjects: Fetal lambs of 16 time-dated pregnant ewes, at 80 days gestation (term 140 to 145 days)., Measurements and Main Results: The congenital diaphragmatic hernia lamb model was created in 16 animals. Twelve animals survived to be studied. All animals were mechanically ventilated for 4 hrs with a time-cycled, pressure-limited ventilator. Perfluorocarbon-associated gas exchange was started after 15 mins of ventilation (n = 6). Blood gases were analyzed at 30 mins and then hourly. The perfluorocarbon-associated gas exchange animals had dynamic compliance and tidal volumes measured. After 1 hr, inhaled nitric oxide (80 parts per million) was delivered to the perfluorocarbon-associated gas exchange animals for 10 mins. All blood gas parameters, including pH (6.72 +/- 0.06 vs. 7.14 +/- 0.07), PCO2 (186 +/- 12 vs. 70.5 +/- 16.7 torr [24.8 +/- 1.6 vs. 9.5 +/- 2.1 kPa]), and PO2 (48 +/- 17 vs. 156 +/- 48 torr [6.4 +/- 2.3 vs. 20.8 +/- 6.4 kPa]) were significantly improved in the perfluorocarbon-associated gas exchange-treated group at 4 hrs (p < .005). Dynamic compliance (0.13 +/- 0.02 vs. 0.32 +/- 0.06 mL/cm H2O/kg) and tidal volume (3.5 +/- 0.35 vs. 7.22 +/- 0.61 mL/kg) were also significantly (p < .001) increased in the perfluorocarbon-associated gas exchange group. In the perfluorocarbon-associated gas exchange animals, nitric oxide caused a significant (p < .05) increase in oxygenation and a reduction in pulmonary hypertension. This effect was reversed by stopping the inhaled nitric oxide., Conclusions: Perfluorocarbon-associated gas exchange significantly improved gas exchange, dynamic compliance, and tidal volumes. Furthermore, inhaled nitric oxide can be effectively delivered during perfluorocarbon-associated gas exchange to reduce pulmonary hypertension and enhance oxygenation.

Objective: To characterize the natural history and outcome of spontaneous pneumothorax in patients under age 16 years., Design: This is a retrospective review in which all patients admitted to the authors' institution (between December 1980 and July 1993) with a diagnosis of spontaneous pneumothorax were included. Information was obtained from the hospital records., Setting: This study was performed in a university childrens' hospital., Patients: All patients under 16 years with a diagnosis of spontaneous pneumothorax were included., Results: Seventeen patients were admitted and analyzed. Only three admissions were for recurrence. The main symptoms included chest pain (100%), shortness of breath (41%), and cough (6%). Chest tube drainage was successful in 65% of the cases; the median time was 4 days. Two patients had a persistent air leak. An underlying cause was recognized in 42% of cases. Seven operations were necessary, and the mean follow-up periods is 31 months, with no recurrence reported to date., Conclusion: Spontaneous pneumothorax occurs in the pediatric population, although it is less common in adults. An underlying pathology is more frequently observed in pediatric patients, but recurrence is less common. Chest tube drainage alone is sufficient treatment for the majority of patients; however, a significant number require some form of surgical intervention.

The pathophysiologic features of congenital diaphragmatic hernia (CDH) include pulmonary hypoplasia, pulmonary hypertension, surfactant deficiency, and decreased pulmonary compliance. When the surfactant deficiency is corrected using exogenous surfactant therapy, the pulmonary compliance improves, but does not reach normal values. Quasistatic saline pressure-volume measurements, which eliminate the air-liquid interface, confirm that CDH lungs are intrinsically less compliant than control lungs. The authors hypothesized that this abnormal lung compliance results from elevated concentrations of collagen and/or elastin in the lung. Therefore, they measured the collagen and elastin concentrations in CDH and control lung tissue. Also measured was the collagen concentration in the kidney, intestine, and dissected third-generation arterioles, venules, and bronchioles, to characterize further the pathology of CDH. The CDH model was created on the left side of fetuses in pregnant ewes at 80 days' gestation. The fetuses were delivered and killed at 140 days (full term, 145). The concentrations of collagen (as hydroxyproline), elastin, DNA, and total protein were measured using standard techniques. Although there was significantly more collagen per gram of lung tissue in the CDH lungs (1.334 mg/g v 0.885 mg/g in the controls) the elastin concentrations were not different. The elevated collagen concentration was not associated specifically with the conducting airways or vasculature. The collagen concentrations in CDH kidneys and intestines were the same as those of controls. The DNA/total protein ratios in the CDH and control lungs were identical. The results suggest that the elevated collagen concentration was present only in the lungs of CDH lambs, and that it was not attributable to atrophy or hypertrophy of the lungs. Thus, increased collagen in the lung parenchyma may be responsible for the intrinsic stiffness and decreased compliance of the CDH lungs.

Aim: The purpose of this study was to determine whether the presence of bowel in the chest during development in the fetal lamb model of congenital diaphragmatic hernia (CDH) results in structural and/or biochemical hypoplasia of the left venticle., Methods: The model was created at 80 days' gestation and delivered at term. The hearts were fixed in 4% formaldehyde solution, components weighed, and right ventricular (RV) and left ventricular (LV) wall thicknesses and both aortic (Ao) and pulmonary artery (PA) root diameters were measured. Fresh specimens were analyzed for protein, DNA, hydroxyproline, and elastin content. All CDH measurements are compared with littermate control tissues., Results: There were no differences in body weight (kg) between CDH and control littermates (4.25 +/- 0.26 versus 3.71 +/- 0.24, P = NS). CDH lambs have significantly decreased total heart (4.88 +/- .25 versus 6.75 +/- .49, P < .05), left ventricular (1.65 +/- .11 versus 2.15 +/- .19, P < .05), septal (1.29 +/- .11 versus 1.99 +/- .21, P < .05), and combined atrial (0.68 +/- .06 versus 1.14 +/- .15, P < .05) weights (g/kg lamb) without differences in RV weights (1.26 +/- .07 versus 1.57 +/- .17, P = NS). LV and RV wall thickness, and Ao root diameters (cm) were found to be identical in both CDH and control lambs. However, PA root diameters (0.47 +/- .01 versus 0.38 +/- .01, P < .005) and ductus arteriosus diameters were increased in CDH (0.35 +/- .01 versus 0.22 +/- .02, P < .005). Total protein, DNA collagen, and elastin content and DNA/total protein ratios were identical in RV and LV in both CDH and control lambs., Conclusion: Newborn lambs with left-sided CDH have a significantly lower total heart, LV, septal, and atrial weights without differences of RV weight or ventricular wall thicknesses. Given these findings, the unchanged DNA/protein ratio implies that the left ventricle is hypoplastic in CDH. Ao/PA root ratios suggest that LV hypoplasia in utero may result in increased left atrial pressures, decreased right-to-left shunting through the foramen ovale, and increased PA pressures and flow, resulting in increased PA root and ductus arteriosus diameters. This model simulates the clinical data from human fetuses/neonates with CDH. Further investigations are necessary to determine the functional significance of these findings.