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Esophageal leiomyomas are the most common benign mesenchymal esophageal tumors, but they occur rarely in the pediatric population. Leiomyomas are conventionally treated with extramucosal enucleation via an open thoracotomy. In this paper, we report a case of a complex massive retrocardiac esophageal leiomyoma that was successfully extirpated by using a robotic-assisted thoracoscopic technique. Intraoperative esophagoscopy and transillumination were useful adjuncts in identifying the esophagus and developing a safe extramucosal dissection plane.

Background To reduce the incidence of early arteriovenous fistula failure (AVF) due to thrombosis in pediatric hemodialysis (HD) patients, a primary thromboprophylaxis (PTP) protocol was initiated at author's institution in June 2005. The goal of this study is to report author's experience with this protocol one year later. Methods and Results 19 AVFs (14 patients, Historical group) and 8 AVFs (7 patients, PTP group) were created prior to and after initiation of PTP respectively. PTP consisted of unfractionated heparin (5–10 units/kg/hr) infusion postoperatively, followed by subcutaneous low molecular weigh heparin (LMWH) until AVF was matured. LMWH dosing was “Prophylactic” (0.5 mg/kg/d, anti-factor Xa levels: peak 0.25–0.5 and trough < 0.3 units/mL) and “Therapeutic” (1 mg/kg/d, anti-factor Xa level: peak 0.5-1 and trough < 0.5 units/mL) based on thrombosis predisposition. In Historical group, 12 AVFs did not receive thromboprophylaxis (No-treatment group), 5 received 81 mg aspirin/day (Aspirin group), and 2 received LMWH. In No-treatment group 10/12 AVFs failed: 9 thromboses and 1 stenosis. In Aspirin group 1/5 AVFs failed due to thrombosis. In PTP group 1/8 AVFs failed due to stenosis; the first 2 AVFs developed hematoma prompting a reduction in LMWH dose and monitoring trough anti-factor Xa levels, one AVF required thrombectomy after LMWH was transiently held. The incidence of thrombosis was less in PTP group (12.5%) when comparing to No-treatment group (83%) (p < 0.05). Conclusion PTP is a feasible option to prevent early thrombosis at AVF. Close clinical and laboratory monitoring including trough anti-factor Xa levels is required to adjust optimum anticoagulation. Larger studies are needed to clarify safety and efficacy of our PTP protocol.

Negative pressure generated during the expiratory phase of total liquid ventilation (TLV) may induce airway collapse. Evaluation of the effect of repeated airway collapse is crucial to optimize this technique. A total of 24 New Zealand White rabbits were randomly divided into four groups. Ventilation was performed for 6 hours with different strategies: conventional gas ventilation, TLV without airway collapse, and TLV with collapse induced in either 75 or 150 sequential breaths. In the treated groups, airway collapse was induced by increasing the perfluorocarbon drainage velocity while maintaining the minute ventilation constant. Airway pressure, gas exchange, and blood pressure were monitored at 30-minute intervals. At the end of the experiment, airway and lung parenchyma specimens were processed for light microscopy. No evidence of fluorothorax was noticed in any of the four groups at autopsy examination. Minimal signs of inflammation were noticed in all airway and lung parenchyma specimens, but no evident structural alteration was visible. Adequate gas exchange and systemic blood pressure were maintained during all the studies. Repeated airway collapse is not associated with structural changes in the respiratory system and does not alter the gas exchange ability of the lungs.

Background A thoracic artificial lung, the MC3 Biolung, is being developed as a bridge to lung transplantation or as a treatment for acute respiratory insufficiency. Methods The thoracic artificial lung was tested in 10 sheep with the goal of 7 days of respiratory support. The sheep were recovered from surgery and monitored awake for 7 days. Hemodynamics, blood gases, blood cell counts, and organ function were recorded, and after 7 days, all sheep were euthanized and necropsied. Results Seven sheep survived the full duration. Cardiac output and mean arterial blood pressure were unchanged, averaging 4.7 ± 0.8 L/min and 98 ± 10 mm Hg, respectively. Arterial oxygen tension and device oxygen transfer rate were also unchanged, averaging 110 ± 26 mm Hg and 97.7 ± 35 mL/min, respectively. Arterial carbon dioxide tension was within normal ranges during the entire experiment, averaging 37.4 ± 3.8 mm Hg. Artificial lung blood flow decreased from 51% ± 14% of cardiac output on day 1 to 30% ± 16% by day 7 because of changes in natural and artificial lung resistance. White blood cell counts were significantly elevated on days 5 and 7, and lastly, kidney and liver function remained normal, although signs of kidney infarction or hemorrhage were noted. Conclusions The thoracic artificial lung is suitable for 7-day attachment, but improvements in blood biocompatibility are warranted.

Purpose Increasing numbers of programs participating in the pediatric surgery match has resulted in economic and logistical issues for candidates, General Surgery residencies, and Pediatric Surgery training programs (PSTP). We sought to determine the ideal number of interviews conducted by programs based on resultant rank order lists (ROL) of matched candidates. Methods PSTPs received 4 online surveys regarding interview practices (2011–2012, 2014), and matched candidate ROL (2008–2010, 2012, 2014). Program directors (PD) also provided estimates regarding minimum candidate interview numbers necessary for an effective match (2011–2012, 2014). Kruskal–Wallis equality-of-populations rank tests compared ROL and interview numbers conducted. Quartile regression predicted ROL based on the interview numbers. Wilcoxon signed rank-sum tests compared the interview numbers to the minimal interview number using a matched pair. p Values Results Survey response rates ranged from 85–100%. Median ROL of matched candidates (2–3.5) did not differ between programs (p=0.09) and the lowest matched ROL for any year was 10–12. Interview numbers did not affect the final candidate ROL (p=0.22). While PDs thought the minimum median interview number should be 20, the number actually conducted was significantly higher (p Conclusion These data suggest that PSTPs interview excessive numbers of candidates. Programs and applicants should evaluate mechanisms to reduce interviews to limit costs and effort associated with the match.

This is a review of the University of Michigan experience with extracorporeal life support (ECLS) also known as extracorporeal membrane oxygenation (ECMO). Two thousand patients were managed with ECMO from 1973 to 2010. The first 1,000 patients were reported previously. Of the 2,000 patients, 74% were weaned from ECLS, and 64% survived to hospital discharge. In patients with respiratory failure, survival to hospital discharge was 84% in 799 neonates, 76% in 239 children, and 50% in 353 adults. Survival in patients with cardiac failure was 45% in 361 children and 38% in 119 adults. ECLS during extracorporeal cardiopulmonary resuscitation was performed in 129 patients, with 41% surviving to discharge. Survival decreased from 74 to 55% between the first and second 1,000 patients. The most common complication was bleeding at sites other than the head, with an incidence of 39%, and the least frequent complication was pump malfunction, with a 2% incidence. Intracranial bleeding or infarction occurred in 8% of patients, with a 43% survival rate. This is the largest series of ECLS at one institution reported in the world to date. Our experience has shown that ECLS saves lives of moribund patients with acute pulmonary and cardiac failure in all age groups.

An implantable pediatric artificial lung (PAL) may serve as a bridge to lung transplantation for children with end-stage lung failure (ESLF); however, an animal model of pediatric lung failure is needed to evaluate the efficacy of PAL before it can enter clinical trials. The objective of this study was to assess ligation of the right pulmonary artery (rPA) as a model for pediatric ESLF. Seven lambs weighing 20-30 kg underwent rPA ligation and were recovered and monitored for up to 4 days. Intraoperatively, rPA ligation significantly increased physiologic dead space fraction (Vd/Vt; baseline = 48.6 ± 5.7%, rPA ligation = 60.1 ± 5.2%, p = 0.012), mean pulmonary arterial pressure (mPPA; baseline = 17.4 ± 2.2 mm Hg, rPA ligation = 28.5 ± 5.2 mm Hg, p < 0.001), and arterial partial pressure of carbon dioxide (baseline = 40.4 ± 9.3 mm Hg, rPA ligation = 57.3 ± 12.7 mm Hg, p = 0.026). Of the seven lambs, three were unable to be weaned from mechanical ventilation postoperatively, three were successfully weaned but suffered cardiorespiratory failure within 4 days, and one survived all 4 days. All four animals that were successfully weaned from mechanical ventilation had persistent pulmonary hypertension (mPPA = 28.6 ± 2.2 mm Hg) and remained tachypneic (respiratory rate = 63 ± 21 min). Three of the four recovered lambs required supplemental oxygen. We conclude that rPA ligation creates the physiologic derangements commonly seen in pediatric ESLF and may be suitable for testing and implanting a PAL.

The focus of this study is an experimental apparatus that serves as a model for studying blood flow in a total artificial lung (TAL), a prototype device intended to serve as a bridge to lung transplantation or that supports pulmonary function during the treatment of severe respiratory failure. The TAL consists of hollow cylindrical fibers that oxygen-rich air flows through and oxygen-poor blood flows around. Because gas diffusivity in the TAL is very small, a convection mechanism dominates the gas transport, which is why we focus on the velocity around the fibers (modeled as a 0.05-cm-in-diameter and 5-cm-long cylinder). We designed a low-speed water tunnel to study the flow mechanism around the cylinder, across which the flow is generated by a linear actuator that allows different flow patterns to mimic the flow in a TAL. We tested the flow in the test section by numerical simulation and by the particle image velocimetry method to study the flow profile. The results show a uniform flow near the centerline of the water tunnel where the cylinder is placed. This decreases the effects of free-stream turbulence in the shear layers and reduces the uncertainty in determining the flow patterns around the cylinder. Knowledge gained from the flow around one cylinder (fiber) is beneficial for understanding vortex formation around multiple cylinders. We present a summary of vortex formation behind a cylinder for Reynolds numbers (Re) of 1, 3, and 5 and Stokes numbers (Ns) of 0.18 to 0.37; results show that higher Re and Ns favor vortex formation. These findings regarding the parameter range for vortex formation may provide principles for designing artificial lungs to enhance convective mixing. We anticipate that the pulsatile flow circuit presented here can be used to mimic the flow not only in TALs but in other physiological systems.

Perforated necrotizing enterocolitis is a major cause of morbidity and mortality in premature infants, and the optimal treatment is uncertain. We designed this multicenter randomized trial to compare outcomes of primary peritoneal drainage with laparotomy and bowel resection in preterm infants with perforated necrotizing enterocolitis.We randomly assigned 117 preterm infants (delivered before 34 weeks of gestation) with birth weights less than 1500 g and perforated necrotizing enterocolitis at 15 pediatric centers to undergo primary peritoneal drainage or laparotomy with bowel resection. Postoperative care was standardized. The primary outcome was survival at 90 days postoperatively. Secondary outcomes included dependence on parenteral nutrition 90 days postoperatively and length of hospital stay.At 90 days postoperatively, 19 of 55 infants assigned to primary peritoneal drainage had died (34.5 percent), as compared with 22 of 62 infants assigned to laparotomy (35.5 percent, P=0.92). The percentages of infants who depended on total parenteral nutrition were 17 of 36 (47.2 percent) in the peritoneal-drainage group and 16 of 40 (40.0 percent) in the laparotomy group (P=0.53). The mean (+/-SD) length of hospitalization for the 76 infants who were alive 90 days after operation was similar in the primary peritoneal-drainage and laparotomy groups (126+/-58 days and 116+/-56 days, respectively; P=0.43). Subgroup analyses stratified according to the presence or absence of radiographic evidence of extensive necrotizing enterocolitis (pneumatosis intestinalis), gestational age of less than 25 weeks, and serum pH less than 7.30 at presentation showed no significant advantage of either treatment in any group.The type of operation performed for perforated necrotizing enterocolitis does not influence survival or other clinically important early outcomes in preterm infants. (ClinicalTrials.gov number, NCT00252681.).

This study examined the effect of artificial lung compliance (C) on pulmonary system (PS) impedance and right ventricular function during in-series attachment of the MC3 Biolung in adult sheep. Compliances, C, of 0-20 ml/mm Hg were tested at the Biolung inlet. Results indicate the PS 0 harmonic input impedance modulus was not affected by C. The PS first harmonic input impedance modulus (Z1) was 10.9 +/- 3.2 mm Hg/(l/min) at C = 0 ml/mm Hg and minimized to 2.41 +/- 0.79 mm Hg/(l/min) at Cor = 0.5 ml/mm Hg. Cardiac output was 58% +/- 10% of its pre-Biolung attachment, baseline value at C = 0 ml/mm Hg and was maximized to an average of 75% +/- 11% at Cor = 0.5 ml/mm Hg. The left ventricular lateral-to-anteroposterior axis length ratio, which decreases with leftward septal shift, increased with C from 0.52 +/- 0.12 at C = 0 ml/mm Hg to 0.76 +/- 0.06 at C = 5 ml/mm Hg (p0.05), but decreased slightly with C at C5 ml/mm Hg. Therefore, the ideal C for right ventricular function is at least 0.5 ml/mm Hg and may be as high as 5 ml/mm Hg to minimize septal shift.

Artificial lungs may serve as transplant alternatives to patients with respiratory failure. To provide a pulmonary replacement, the device cannot significantly alter right ventricular afterload. We sought to characterize cardiac load using a prototype artificial lung as a pulmonary replacement. An artificial lung was implanted into 13 adult sheep, 7 using a noncompliant original prototype and 6 using a modified device with a compliance chamber. Inflow was from the pulmonary artery and outflow into the left atrium. Pulmonary impedance was determined and pulse wave reflections analyzed. Resistance was similar in the original prototype artificial lung and in the native pulmonary circulation (3.0 vs 3.2 Woods units, p = 0.5). First harmonic impedance was significantly increased in the original prototype artificial lung (0.4 vs 5.9 Woods units, p < 0.01). High-amplitude pulse wave reflections were identified and right ventricular function was altered. The addition of compliance to the artificial lung reduced impedance at the first harmonic (5.9 vs 1.9 Woods units, p < 0.01), decreased the amplitude of pulse wave reflections, and normalized right ventricular function. A low-resistance but noncompliant artificial lung increases pulmonary impedance and alters right ventricular function. Addition of a compliance chamber reduces pulse wave reflections and normalizes ventricular function.

This in vitro study sought to determine what compliance minimizes thoracic artificial lung impedance and pump power output. A pulsatile pump drove 3.0 cP glycerol through a circuit consisting of an MC3 Biolung preceded by a piston-cylinder (PC, n = 5) chamber with a variable compliance or a polyurethane (n = 4) chamber with a fixed, yet pressure-dependent, compliance. Each chamber was tested at flow rates of 1.8, 3.0, and 5.0 l/min and heart rates of 60, 75, and 100 bpm. Compliances, C, from 0-20 ml/mm Hg were tested in the PC chamber. Instantaneous pump outlet flow and pressure were acquired for determination of device zeroth and first harmonic input impedance, Z(0) and Z(1), and pump steady and pulsatile output powers, P(s) and P(p). PC chamber results indicate that Z(0), Z(1), P(s), and Pp were minimized at C > 1, 5, 0.5, and 4 ml/mm Hg, respectively. This suggests that C should be 1 ml/mm Hg at minimum and ideally 5 ml/mm Hg. The polyurethane chamber was statistically similar to the PC chamber at C = 1 ml/mm Hg when comparing Z(0) and P(s), but was statistically inferior when comparing Z(1) and P(p). The polyurethane compliance chamber, therefore, should be redesigned with greater compliance.

Neonates receiving parenteral nutrition (PN) are at risk for PN-associated cholestasis (PNAC); however, no preventive factors for PNAC have been clearly identified. Despite reports suggesting that taurine may prevent PNAC in neonates, such an effect of taurine has not yet been definitively demonstrated. We determined whether taurine supplementation reduces the incidence of PNAC in premature or critically ill neonates.This study was part of a prospective, randomized, multi-institutional trial designed to assess cholecystokinin vs placebo as a potential preventive therapy of PNAC. Taurine supplementation of PN varied between institutions. The presence or absence of taurine in PN was analyzed by multivariate analysis, with a primary outcome measure of serum conjugated bilirubin (CB) as a measure of PNAC.Taurine reduced PNAC in premature infants (estimated maximum CB [95% confidence interval] 0.50 mg/dL [-0.17 to 1.18] for those receiving taurine, vs 3.45 mg/dL [1.79-5.11] for neonates not receiving taurine, approaching significance, p = .07). Taurine significantly reduced PNAC in infants with necrotizing enterocolitis (NEC; estimated maximum CB 4.04 mg/dL [2.85-5.23], NEC infants receiving taurine, vs 8.29 mg/dL [5.61-10.96], NEC infants not receiving taurine, p.01). There were too few neonates with surgical anomalies to evaluate the effect of taurine in this group.Within specific subgroups of neonatal patients, taurine supplementation does offer a very significant degree of protection against PNAC. Patients with NEC or severe prematurity are most likely to benefit substantially from taurine supplementation.

Background As a first step toward the development of an artificial placenta, we investigated the relationship between blood flow rate through an arteriovenous (A-V) circuit/oxygenator and both CO 2 elimination and hemodynamic stability in a small animal model. Methods Male New Zealand rabbits (N = 10) with an average weight of 2.7 ± 0.2 kg were anesthetized, paralyzed, and heparinized before carotid-jugular cannulation. A tracheostomy tube, an arterial catheter, and an aortic flow probe were placed. Arteriovenous flow through a custom-made, low-resistance, 0.5 m 2 hollow fiber oxygenator was initiated. Oxygen sweep flow was maintained at 300 mL/min, whereas blood flow was controlled at 10 to 40 mL/(kg min). Ventilation was discontinued during each blood flow rate trial. Hemodynamic and preoxygenator and postoxygenator blood gas data were recorded 30 minutes after initiation of each flow rate. CO 2 removal was the product of the oxygen sweep gas flow rate and the sweep flow exhaust CO 2 content as determined by capnometry. Data were analyzed by analysis of variance with post hoc Dunnett's t test. Results CO 2 removal increased and Paco 2 decreased as a function of A-V blood flow rate. Simultaneously, systolic blood pressure did not significantly change. CO 2 removal was effective at device flows greater than 20% of cardiac output. Conclusion In this rabbit model, A-V blood flows at 25% to 30% of cardiac output allow full gas exchange without hemodynamic compromise. This model raises the possibility of using A-V support and an artificial placenta in newborns with respiratory failure.

Objective. To determine whether cholecystokinin-octapeptide (CCK-OP) would prevent or ameliorate parenteral nutrition-associated cholestasis (PNAC) among high-risk neonates treated with total parenteral nutrition.Study Design. This was a multicenter, double-blind, randomized, controlled trial conducted between 1996 and 2001.Patients. Neonates at risk for the development of PNAC included very low birth weight neonates and those with major surgical conditions involving the gastrointestinal tract.Setting. Tertiary care hospitals.Intervention. Patients were randomized to receive CCK-OP (0.04 μg/kg per dose, twice daily) or placebo. Eligible infants were all Outcome Measures. The primary outcome measure was conjugated bilirubin (CB) levels, which were measured weekly. Secondary outcome measures included incidence of sepsis, times to achieve 50% and 100% of energy intake through the enteral route, number of ICU and hospital days, mortality rate, and incidences of biliary sludge and cholelithiasis.Results. A total of 243 neonates were enrolled in the study. CCK-OP administration did not significantly affect CB levels (1.76 ± 3.14 and 1.93 ± 3.31 mg/dL for CCK-OP and placebo groups, respectively; mean ± SD). Secondary outcome measures also were not significantly affected by the study drug.Conclusions. Use of CCK-OP failed to reduce significantly the incidence of PNAC or levels of CB. CCK-OP had no effect on other secondary measures and should not be recommended for the prevention of PNAC.

Flow limitation in liquid-filled lungs is examined in intact rabbit experiments and a theoretical model. Flow limitation (“choked” flow) occurs when the expiratory flow reaches a maximum value and further increases in driving pressure do not increase the flow. In total liquid ventilation this is characterized by the sudden development of excessively negative airway pressures and airway collapse at the choke point. The occurrence of flow limitation limits the efficacy of total liquid ventilation by reducing the minute ventilation. In this paper we investigate the effects of liquid properties on flow limitation in liquid-filled lungs. It is found that the behavior of liquids with similar densities and viscosities can be quite different. The results of the theoretical model, which incorporates alveolar compliance and airway resistance, agrees qualitatively well with the experimental results. Lung compliance and airway resistance are shown to vary with the perfluorocarbon liquid used to fill the lungs. Surfactant is found to modify the interfacial tension between saline and perfluorocarbon, and surfactant activity at the interface of perfluorocarbon and the native aqueous lining of the lungs appears to induce hysteresis in pressure–volume curves for liquid-filled lungs. Ventilation with a liquid that results in low viscous resistance and high elastic recoil can reduce the amount of liquid remaining in the lungs when choke occurs, and, therefore, may be desirable for liquid ventilation.

Purpose Laparoscopy has recently been used to treat intussusception that cannot be reduced radiologically. The effectiveness and practical nature of this approach has been questioned. Methods This study retrospectively analyzed the authors' experience with this laparoscopic approach and compared this to the conventional open laparotomy procedure. Results Sixteen patients were treated via laparoscopy, with 2 of these requiring conversions to an open procedure (12.5%). Twenty-five patients underwent an open reduction. Operative time was not significantly different ( P = .698) between the laparoscopic (49.56 ± 26.40 minutes) and open groups (45.00 ± 24.74). Length of stay, however, was significantly reduced ( P = .005) in the laparoscopic group (3.00 ± 1.31 days) compared to the open group (4.52 ± 1.98). Total hospital charges were lower in the laparoscopic group ($8171 ± 2595) compared to the open group ($11,672 ± 5466); this difference was not significant ( P = .088). There were no significant differences in intra- or postoperative complication rates ( P = .637) between the 2 approaches. Conclusions Although there remains a group who will require a conversion to an open procedure, the laparoscopic approach should be considered a safe and effective option for all children who do not respond to a radiological reduction.

Background/purpose Billing and reimbursement for pediatric surgical services is a complicated process that has not been rigorously evaluated. This study evaluates pediatric surgery billing and reimbursement and compares the process between third party payors. Methods The authors tracked all noncapitated bills from submission to final payment for all cases performed during 1 month. Data included operation, insurance type, amount billed, and amount collected. If payments were denied, the reasons were ascertained and the appropriateness verified. Chi-square and Student's t tests were used for comparisons. Results The billing process for all noncapitated pediatric surgical cases during May 2000, was reviewed (n = 136). The majority of bills (79%) were paid outright. Of the rejected bills, 76% were denied inappropriately. Inappropriate denial of payment was most frequent among patients insured by Medicaid. Mean time to complete payment was longest among patients insured by managed care groups. Percent of total charges reimbursed for surgical services was significantly lower for patients insured by Medicaid and Health Maintenance Organizations (HMO). Conclusions A significant number of bills for pediatric surgical services are rejected inappropriately. Careful analysis of one's rejected bills can recoup up to 20% of revenue. HMO's and Medicaid are more likely to deny payment inappropriately, take longer to make payments, and reimburse less for pediatric surgical services.

Motivated by the goal of understanding how to most homogeneously fill the lungs with perfluorocarbon for liquid ventilation, we investigate the transport of liquid instilled into the lungs using an intact rabbit model. Perfluorocarbon is instilled into the trachea of the ventilated animal. Radiographic images of the perfluorocarbon distribution are obtained at a rate of 30 frames/s during the filling process. Image analysis is used to quantify the liquid distribution (center of mass, spatial standard deviation, skewness, kurtosis, and indicators of homogeneity) as time progresses. We compare the distribution dynamics in supine animals to those in upright animals for three constant infusion rates of perfluorocarbon: 15, 40, and 60 ml/min. It is found that formation of liquid plugs in large airways, which is affected by posture and infusion rate, can result in a more homogeneous liquid distribution than gravity drainage alone. The supine posture resulted in more homogeneous filling of the lungs than did upright posture, in which the lungs tend to fill in the inferior regions first. Faster instillation of perfluorocarbon results in liquid plugs forming in large airways and, consequently, more uniform distribution of perfluorocarbon than slower instillation rates in the upright animals.

Purpose Late-onset hyperbilirubinemia in patients who have undergone a successful portoenterostomy (PE) for biliary atresia (BA) is usually considered evidence of ongoing severe liver failure. The authors recently have treated 2 patients who had acute hyperbilirubinemia years and months after a successful PE and had dilated intrahepatic cysts. A combined operative and percutaneous approach reestablished drainage and a reduction in their bilirubin levels. Methods Data from 2 cases of BA and late-onset hyperbilirubinemia from obstruction were reviewed and analyzed. Results Two patients (15-year-old boy and a 2.5-year-old girl) presented with increasing serum bilirubin after a PE for BA in infancy. Both had extensive preoperative workup, which showed intrahepatic biliary dilatation in one and a large bile lake in the other. They underwent attempted percutaneous transhepatic cholangiography and stenting, followed by an intraoperative transhepatic approach in which the dilated ducts were connected to the PE. A rapid and sustained reduction in the serum bilirubin level was noted in these patients. Conclusions When patients with BA after a successful PE present with sudden onset of hyperbilirubinemia, imaging for biliary obstruction should be carried out. If biliary dilatation is found, then a combined radiologic and operative approach may help improve the bile flow and delay the need for liver transplant.

Background/purpose Over the last 4 years, the authors changed their management of acute nonperforated appendicitis from emergent surgery within the first 2 to 6 hours of admission to initiation of antibiotic therapy with operation within 24 hours of admission in those seen in the late evening or early morning. They examined, therefore, whether a delay in operation for acute appendicitis would affect outcome measures of patient morbidity and resource use. Methods The medical records of 126 patients with acute appendicitis occurring between 1998 and 2001 were retrospectively reviewed. Incidence of perforation at surgery, length of stay (LOS), hospital charges, operating time, and complications as a function of duration between emergency room (ER) triage and operation (ER-OR) or admission and operation (Admit-OR) were analyzed by Student's t test, and regression analysis with P less than .05 considered significant. Results Thirty-eight children (26%) were operated on within 6 hours of ER triage, whereas the remaining 88 children (74%) were operated on between 6 and 24 hours from ER triage. No significant difference was noted in perforation rate, LOS, costs, or operative time, nor were substantial changes in complications noted between those with an ER-OR ≤6 hours and greater than 6 hours. Likewise, no significant differences in these outcome measures were noted for Admit-OR greater than 6 when compared with ≤6 hours. Only costs with ER-OR greater than 12 hours and LOS with Admit-OR greater than 6 hours were significantly (without Bonferroni correction) different than ≤ 6 hours. Multivariable linear regression analysis identified only LOS as a significant predictor of time to OR. Conclusions In children with acute appendicitis, delaying surgery until the daytime hours did not significantly affect operating time, perforation rate, or complications. Delayed management allows greater efficiency and effective use of physician and hospital resources, including decreased resident involvement in operations during the night.

The concept of liquid ventilation has been investigated for almost 40 years. Kylstra,1 in 1962, demonstrated the ability to sustain gas exchange in dogs spontaneously breathing saline oxygenated at 6 atmospheres. Clark2 subsequently demonstrated that spontaneously breathing mice could survive when submerged in perfluorocarbon under normobaric conditions. Perfluorocarbons are structurally similar to hydrocarbons with the hydrogen replaced by fluorine. The carbon chains vary in length and an additional moiety often is attached to the molecule which, together, give unique properties to each perfluorocarbon. In general, perfluorocarbons have excellent oxygen and carbon dioxide carrying capacity (50mlO2/dl and 160−210mlCO2/dl, respectively).3 They are clear, odorless, inert fluids which are immiscible in aqueous and most other solutions. They are relatively dense (1.7−1.9 gm/mL), have a low surface tension (15−19 dynes/cm), and are relatively volatile with vapor pressures ranging from 11 to 85 torr at 37oC. The vapor pressure of the individual perfluorocarbon governs the rapidity with which it evaporates from the lungs after intratracheal administration. Liquid ventilation has been performed by two methods.3 The first is total liquid ventilation (TLV) in which the lungs are filled with perfluorocarbon to a volume equivalent to functional residual capacity (FRC) upon which a device is utilised to ventilate the perfluorocarbon-filled lung with perfluorocarbon.4 The second technique of liquid ventilation involves administration of intratracheal perfluorocarbon to a volume equivalent to functional residual capacity followed by standard gas mechanical ventilation of the perfluorocarbon-filled lung

To compare pump driven (active) and gravity-siphon (passive) expiration modes during perfluorocarbon total liquid ventilation (TLV), a liquid ventilator was developed capable of providing either expiration mode. In a prospective, controlled laboratory study, 90 rabbits (3.2 +/- 0.1 kg) were anesthetized, tracheotomized, killed. After prefill with 12 ml/kg perflubron and TLV for 90 minutes (tidal volume 12 ml/kg, I:E ratio 1:2), randomly using passive (height 40 or 80 cm) or active expiration, respiratory rates were 4, 8, or 12/min. Static peak inspiratory and end-expiratory intratracheal pressures were measured at 5 minute intervals. Peak inspiratory and end-expiratory were constant in active groups, and increases in all 40 cm and 80 cm passive groups were significant. Differences between groups were significant for expiratory mode but not for respiratory rates. Only passive groups showed significant increases in body weight after TLV. Percentage of fluorothoraces was 10% using active and 85% using passive expiration. Based upon the stability of intrapulmonary pressures and volumes and a reduced rate of fluorothoraces, active expiration is more efficient than passive drainage during TLV.

The aim of this study was to utilize clinical outcome methodology through multivariable analysis of perioperative factors to predict a successful Kasai-portoenterostomy (PE).Records of 81 patients treated for biliary atresia (BA) were reviewed. Outcome was defined as successful if the patient was alive and had no liver transplant (LT). To predict future successful or failed PE, patients were categorized at 6 months post-PE into 2 groups: Success: direct bilirubin (DB) less than 2.0 mg/dL; Failure: DB greater than 2 mg/dL, or the patient was listed/had undergone LT, or had died. Groups were analyzed for positive or negative predictive values (PPV, NPV) at 2 and 5 years after PE. Cox regression was used to determine risk factors for PE.PE was successful in 38% and failed in 62%. PPV of future success was 96% at 2 years post-PE and 95% at 5 years post-PE, NPV of failure was 76% and 74%, respectively. Bridging liver fibrosis at the time of PE and postoperative cholangitic episodes were interdependent risk factors for a failed PE (P.05). Other covariates showed no significant relationship for PE outcome.Classifying of patients 6 months postoperatively allowed us to determine a successful PE outcome. Bridging liver fibrosis at the time of the Kasai, and the increased number of postoperative cholangitic episodes were predictive of a poor PE outcome.

Background In children, restorative proctocolectomy is usually accomplished by a rectal mucosectomy followed by a hand-sewn ileo-anal anastomosis±ileal pouch. In certain patients, a hand-sewn anastomosis can be technically difficult. This led us to develop a new technique that combines endorectal mucosectomy with a double-stapled ileo-anal anastomosis. Methods After colectomy, an ileal J-pouch is constructed. The head of the circular stapler is placed in the apex of the pouch and secured. An endorectal mucosectomy is completed from the abdomen to approximately 1.5 cm above the dentate line. The rectal mucosal/submucosal tube is everted onto the perineum. A transverse stapler is positioned 1.5 cm above the dentate line on the perineum and fired. The circular stapler is inserted transanally and the trocar advanced through the transverse staple line until the head and anvil are mated and then fired. A loop ileostomy is constructed. Results Thirteen patients, with a mean age of 12.3 years, have undergone endorectal mucosectomy with a double-stapled anastomosis without major complication. The operative time averaged 280±70 minutes. The mean 24-hour stool frequency, with 9 months' follow-up, was 6.8±3.2, of which 1±0.7 were at night. Conclusions The combination of endorectal mucosectomy with a double-stapled anastomosis is a new approach for patients requiring restorative proctocolectomy. In our early experience, this technique was completed with a low complication rate and excellent functional results.

OBJECTIVE To determine end-expiratory lung volumes (EELVs) and the distribution of gas and perflubron during low- and high-dose partial liquid ventilation (PLV) in healthy and oleic-acid-injured lungs. DESIGN A prospective, randomized study. SETTING A university medical school laboratory approved for animal research. SUBJECTS Adult sheep. INTERVENTIONS A total of 18 sheep were randomly divided into two groups (healthy and oleic acid lung injury) and received PLV with perflubron at incremental doses. MEASUREMENTS AND MAIN RESULTS Animals were ventilated in a volume-control mode with a positive end-expiratory pressure of 5 cm H2O. Baseline computed tomographic scans of the entire lung were obtained during end-expiratory hold. Thereafter, the animals were randomized to undergo either PLV alone (healthy group) or after oleic acid lung injury was introduced (injury group). In both groups, PLV was induced by instilling 10 mL/kg perflubron into the endotracheal tube over 5 mins (low-dose PLV). At 60 mins after dosing, another set of computed tomographic scans during end-expiratory hold was obtained. Thereafter, another 20 mL/kg perflubron was instilled in both groups (cumulative dose, 30 mL/kg perflubron, high-dose PLV), and computed tomographic scanning was repeated 60 mins later. EELVs were calculated. To study density distribution patterns, the lungs were divided into nine segments, and the mean Hounsfield attenuation number was calculated for each segment. In healthy animals, low-dose PLV did not change EELV (47.5 +/- 8.1 mL/kg vs. 44.5 +/- 6.1 mL/kg at 10 mL/kg perflubron), whereas high-dose PLV significantly increased EELV (58.1 +/- 3.3 mL/kg, p

OBJECTIVES: To investigate the settings necessary to achieve maximum gas exchange and pulmonary function while minimizing effects on cardiovascular hemodynamics during total liquid ventilation with a pressure-limited, time-cycled ventilator in a rat model. DESIGN: Prospective, randomized controlled animal study. SETTING: A university research laboratory. SUBJECTS: Male Sprague-Dawley rats (n = 48). INTERVENTIONS: All animals had a tracheostomy tube designed for total liquid ventilation placed under anesthesia. The carotid artery was cannulated for blood pressure monitoring and for assessing blood gas data. MEASUREMENTS AND MAIN RESULTS: Forty 492 +/- 33 g rats were assigned to one of four inspiratory/expiratory ratio groups (inspiratory/expiratory ratio of 1:2, 1:2.5, 1:3, and 1:4). Total liquid ventilation was performed with a pressure-limited, time-cycled total liquid ventilator. Outcome measures were evaluated as a function of respiratory rate and included tidal volume, maximal alveolar ventilation, inspiratory and expiratory mean arterial pressures, the difference of mean arterial pressure between the inspiratory and expiratory phase, static end-inspiratory/expiratory pressures, Paco(2), Pao(2), tidal volume + approximate expiratory reserve volume, and lung volume-induced suppression of mean arterial pressure. Maximal alveolar ventilation increased and decreased in parabolic fashion as a function of respiratory rate and was maximal at rates of 4.3-6.8 breaths/min and high inspiratory/expiratory ratios that corroborated with optimal levels of Pao(2) and Paco(2). Lung overdistention occurred at high respiratory rates and high inspiratory/expiratory ratios. Deleterious effects were observed on the difference of mean arterial pressure between the inspiratory and expiratory phase during total liquid ventilation at low respiratory rates, apparently due to increased tidal volume, and on suppression of mean arterial pressure at high inspiratory/expiratory ratios and high respiratory rate apparently due to "auto-positive end-expiratory pressure." These effects were minimized in this model at respiratory rates >/=5.7 and

Background: Laparoscopic Nissen fundoplication as treatment for gastroesophageal reflux disease (GERD) in adults has a reported recurrence rate of 2–17%. We investigated the rates and mechanisms of failure after laparoscopic Nissen fundoplication in children. Methods: All patients who underwent a laparoscopic Nissen fundoplication for GERD and who subsequently required a redo Nissen were reviewed (n = 15). The control group consisted of the most recent 15 patients who developed recurrent GER after an open Nissen, fundoplication. Results: Between 1994 and 2000, laparoscopic Nissen fundoplication was performed in 179 patients. Fifteen patients (8.7%) underwent revision. The mechanisms of failure were herniation in four patients, wrap dehiscence in four, a too-short wrap in three, a loosened wrap in two, and other reasons in two. The reoperation was performed laparoscopically in five patients (33%). The failure mechanisms were different in the open patients: eight were due to slipped wraps; three to dehiscences; and two to herniations. Conclusion: The failure rate after laparoscopic Nissen is acceptably low. A redo laparoscopic Nissen can be performed safely after an initial laparoscopic approach.

Partial liquid ventilation (PLV) is a means of ventilatory support in which gas ventilation is carried out in a lung partially filled with a perfluorocarbon liquid capable of supporting gas exchange. Recently, this technique has been proposed as an adjunctive therapy for cardiac arrest, during which PLV with cold perfluorocarbons might rapidly cool the intrathoracic contents and promote cerebral protective hypothermia while not interfering with gas exchange. A concern during such therapy will be the effect of PLV on pulmonary hemodynamics during very low blood flow conditions. In the current study, segmental (i.e. precapillary, capillary, and postcapillary) hemodynamics were studied in the rat lung using a standard isolated lung perfusion system at a flow rate of 6 ml/min ( ~5% normal cardiac output). Lungs received either gas ventilation or 5 or 10 ml/kg PLV. Segmental pressures and vascular resistances were determined, as was transcapillary fluid flux. The relationship between individual hemodynamic parameters and PLV dose was examined using linear regression, with n = 5 in each study group. PLV at both the 5 and 10 ml/kg dose produced no detectable changes in pulmonary blood flow or in transcapillary fluid flux (all R2 values < 0.20). Conclusion: In an isolated perfused lung model of low flow conditions, normal segmental hemodynamic behavior was preserved during liquid ventilation. These data support further investigation of this technique as an adjunct to cardiopulmonary resuscitation.

Background/Purpose: Initial laboratory and clinical data suggest that partial liquid ventilation (PLV) can enhance pulmonary function and that lung growth can be induced via distension of the newborn lung using perfluorocarbon in patients with congenital diaphragmatic hernia (CDH). The authors, therefore, performed a prospective, randomized pilot study evaluating PLV and perfluorocarbon-induced lung growth (PILG) in newborns with CDH on extracorporeal life support (ECLS) at 6 medical centers. Methods: Patients were selected randomly using a permuted block design to PLV/PILG (n = 8) or conventional mechanical ventilation (CMV/control, n=5). Patients in the PILG group received daily doses which filled the lungs with perflubron for up to 7 days and were placed on continuous positive airway pressure of 5 to 8 cm H 2 O. CMV patients were treated with standard mechanical ventilation while on extracorporeal membrane oxygenation (ECMO). Results: A total of 13 patients were evaluated in this study. All 3 patients enrolled without being on ECLS rapidly transitioned to ECLS. The study, therefore, effectively evaluated PILG (n = 8) versus standard ventilation (control, n=5) on ECLS. Mean (± SE) gestational age was 37 ± 1 weeks and weight was 3.1 ± 0.1 kg. Time on ECMO was 9.8 ± 2.3 days in the PILG and 14.5 ± 3.5 days ( P =.58) in the control group. Survival rate in the PILG group was 6 of 8 (75%), whereas survival rate was 2 of 5 (40%) in the control group ( P =.50). The number of days free from the ventilator in the first 28 days (VFD) was 6.3 ± 3.3 days with PILG and 4.6 ± 4.6 days with control ( P =.9). Causes of death in the PILG group included sepsis and renal failure in one patient and pulmonary hypertension in the other. There were no safety issues, and the deaths in the PILG group did not appear to be related to the administration of perflubron. Conclusions: These data show that PILG can be performed safely. The survival rate, VFD, and time on ECMO data, although not conclusive, are encouraging and indicate the need for a definitive trial of this novel intervention in these neonates with high mortality. J Pediatr Surg 38:283-289. Copyright 2003, Elsevier Science (USA). All rights reserved.

Matching the impedance of an artificial lung for pulmonary replacement to native pulmonary impedance is important in preventing right ventricular dysfunction. A lumped-parameter theoretical model and bench-top experiments were used to investigate the effect of a prototype compliance chamber on input impedance. The bench-top simulation consisted of a pulsatile flow generator, a prototype compliance chamber, and a low resistance artificial lung connected in series. Effective compliance was varied using pneumatic compression. The theoretical model considered a similar circuit with resistors before and after a compliance element. The bundle flow pulsatility (flow amplitude divided by average flow) and input impedance were calculated in the theoretical and experimental models. More compliance and lower upstream resistance result in lower bundle flow pulsatility and reduced first harmonic impedance. Matching the time scale of the circuit to the period of pulsatile flow also reduces impedance. The bench-top circuit demonstrated an optimal chamber pressure at which first harmonic impedance is reduced by 80%. The prototype compliance chamber in series with the artificial lung more closely matches native pulmonary impedance. The lumped-parameter model and the bench-top simulation will aid in the design and testing of compliance chamber modifications to improve its efficiency.

Between May 1990 and January 1999, 100 patients (68 adult, 32 pediatric) with severe respiratory or cardiac instability were successfully transported to the University of Michigan Medical Center on extracorporeal life support. Diagnoses included adult respiratory distress syndrome (n = 78), cardiac failure (n = 7), sepsis (n = 7), asthma (n = 5), respiratory distress syndrome (of newborn) (n = 2), and airway compromise (n = 1). Of the patients, 53 were supported with venovenous bypass and 47 with venoarterial bypass. Patients were transported by ground ambulance (n = 80), helicopter (n = 15), or fixed-wing aircraft (n = 5). The median transport distance was 44 miles (range 2-790 miles), and the median transport time was 5 hours and 30 minutes (range: 1 h 33 min to 16 h 6 min). Sixty-six patients (66%) survived to discharge. One death occurred during cannulation, and two patients died before cannulation began. Complications that occurred during transport included 10 cases of electrical failure, 3 cases of circuit tubing leakage, and 1 case each of circuit rupture, membrane lung thrombosis, and membrane lung leakage. None of the complications occurring during transport had an adverse effect on outcome. We conclude that the long distance transport of patients on extracorporeal life support can be safely accomplished and is an effective option for the unstable patient with severe respiratory or cardiac failure.

Ventilator-induced lung injury may be caused by overdistension of alveoli during high-pressure ventilation. In this study, we examined the effects of increasing inspiratory time on ventilator-induced lung injury.Sprague-Dawley rats were divided into four different groups with ten animals per group. Each group was then ventilated for 30 mins with one of four ventilator strategies. All groups were ventilated with an Fio2 of 1.0 and a positive end-expiratory pressure of 0 cm H2O. Group LoP was the negative control group and was ventilated with low pressures (peak inspiratory pressure = 12 cm H2O, rate = 30, and inspiratory time = 0.5 secs). Groups iT = 0.5, iT = 1.0, and iT = 1.5 were the experimental groups and were ventilated with high pressures (peak inspiratory pressure = 45 cm H2O, rate = 10, and inspiratory times = 0.5 secs, iT = 1.0 sec, and iT = 1.5 secs, respectively). Outcome measures included lung compliance, Pao /Fio ratio, wet/dry lung weight, and dry lung/body weight.Final static lung compliance (p =.0002) and Pao2/Fio2 (p =.001) decreased as inspiratory time increased. Wet/dry lung weights (p.0001) and dry lung/body weights (p.0001) increased as inspiratory time increased. Light microscopy revealed evidence of intra-alveolar edema and hemorrhage in the iT = 1.0 and iT = 1.5 animals but not the LoP and iT = 0.5 animals.Increasing inspiratory time during high-pressure/high-volume mechanical ventilation is associated with an increase in variables of lung injury.

Background: Lung transplantation is the only treatment for patients with end-stage lung disease. However, the scarcity of donor organs illustrates the need for alternatives. Recent success in the use of ventricular assistance has stimulated research in technology designed as a bridge to lung transplantation. Some laboratories have demonstrated significant advances in the development of artificial lungs, and clinical applications are on the horizon. In preparation, we sought to gather information from the lung transplant community regarding issues related to testing and potential trials of artificial lungs. Methods: We constructed a survey and distributed it to lung transplant program directors recognized by the United Network for Organ Sharing. Topics included required animal studies, preferred designs, logistics of clinical trials, and patient diagnoses most appropriate for such a trial. Results: The 31 programs responding to the survey performed 72% of all lung transplants in the United States in 1999. Ninety-seven percent supported a Phase I trial using an artificial lung as a bridge to lung transplantation. Additionally, 58% specifically supported a trial in which organ allocation would be prioritized to enrolled patients. Idiopathic pulmonary fibrosis was the diagnosis thought most appropriate for inclusion in initial clinical trials. Conclusions: Widespread support exists for the development and use of an artificial lung as a bridge to lung transplantation. Information from transplant centers regarding device design and application can influence laboratories developing artificial lungs, and such communication will be essential as this technology progresses from the bench-top to the bedside.

Background/Purpose: Proponents of subspecialization in surgery claim that fellowship training improves the quality of care. Others claim that general training is adequate for most routine surgical procedures. The authors questioned whether there were differences in outcomes when general surgeons (GEN) operate on children and infants with common surgical conditions compared with the care of their pediatric surgical (PED) colleagues. Methods: The authors retrospectively reviewed the Healthcare Investment Analysts North Carolina Information Network database to identify patients who underwent pyloromyotomy for congenital hypertrophic pyloric stenosis in North Carolina during the period from October 1995 through September 1998 (n = 780). Information obtained included demographics, insurance type, hospital, length of stay, total hospital charges, occurrence of mucosal perforation, and type of surgeon (general v pediatric). Results: Of the 780 pyloromyotomies performed, 363 (48%) were performed by pediatric surgeons. Pediatric surgeons cared for more Medicaid patients than general surgeons (PED, 52% v GEN, 40%; P = .001). Infants treated by pediatric surgeons had a lower incidence of mucosal perforation (PED, 0.5% v GEN, 2.9%; P = .0015), which was associated with decreased overall total hospital charges (no perforation, $4,806 [plusmn] 79 v perforation, $6,592 [plusmn] 492; P = .002). When patients with uncomplicated pyloric stenosis were evaluated (96% of cases), those cared for by pediatric surgeons had lower total hospital charges (PED, $4,496 [plusmn] 95 v GEN, $5,121 [plusmn] 121; P = .0001) and shorter length of stay (PED, 2.7 [plusmn] 0.1 days v GEN, 3.1 [plusmn] 0.1 days; P = .01). Conclusions: In North Carolina, general surgeons treat more than half the patients who have pyloric stenosis, though fewer with Medicaid. The cost and incidence of mucosal perforation were increased in infants with pyloric stenosis when care was provided by general rather than pediatric surgeons.

Objective: To examine the isolated and combined effects of positive end-expiratory pressure (PEEP) and partial liquid ventilation (PLV) on the development of ventilator-induced lung injury in an ovine model. Design: Prospective controlled animal study. Setting: University-based cardiovascular animal physiology laboratory. Subjects: Thirty-eight anesthetized supine sheep weighing 22.3 ± 2.2 kg. Interventions: Animals were ventilated for 6 hrs (respiratory rate, 15; FIO 2 , 1.0, inspiratory/expiratory ratio, 1:1) with one of five pressure-controlled strategies, expressed as peak inspiratory pressure (PIP)/PEEP: low-PIP, 25/5 cm H 2 O (n = 8); high-PIP, 50/5 cm H 2 O (n = 8); high-PIP-PLV, 50/5 cm H 2 O-PLV (n = 8); high-PEEP, 50/20 cm H 2 O (n = 7); and high-PEEP-PLV, 50/20 cm H 2 O-PLV (n = 7). Measurements and Main Results: Compared with the low-PIP control, high-PIP ventilation increased airleak, shunt, histologic evidence of lung injury, neutrophil infiltrates, and wet lung weight. Maintaining PEEP at 20 cm H 2 O or adding PLV reduced the development of physiologic shunt and dependent histologic injury indexes. Neither higher PEEP nor PLV reduced the high incidence of barotrauma observed in high-PIP animals. Conclusions: We conclude that application of PLV or PEEP at 20 cm H 2 O may improve gas exchange and afford lung protection from ventilator-induced lung injury during high-pressure mechanical ventilation in this model.

The current diagnostic accuracy and perinatal outcome of fetuses with esophageal atresia (EA) continues to be debated. In this review, we report on our experience at a tertiary care fetal center with the prenatal ultrasound diagnosis of EA. Enrollment criteria included a small/absent stomach bubble with a normal or elevated amniotic fluid index between 2005 and 2013. Perinatal outcomes were analyzed and compared to postnatally diagnosed EA cases. Of the 22 fetuses evaluated, polyhydramnios occurred in 73 %. Three (14 %) died in utero or shortly after birth, but none had EA. In the presence of an absent/small stomach and polyhydramnios, the positive predictive value for EA was 67 %. In fetal EA cases confirmed postnatally (group 1, n = 11), there were no differences in gestational age, birthweight, or mortality when compared to postnatally diagnosed infants (group 2, n = 59). Group 1 was associated with long-gap EA, need for esophageal replacement, and increased hospital length of stay. When taken in context with the current literature, we conclude that ultrasound findings suggestive of EA continue to be associated with a relatively high rate of false positives. However, among postnatally confirmed cases, there is an increased risk for long-gap EA and prolonged hospitalization.

Introduction Catheter associated blood stream infections (CABSIs) are morbid and expensive for all ages, including neonates. Thus far, the impact of CABSI prevention protocols, such as insertion and maintenance bundles, in the neonatal intensive care unit (NICU) is largely unknown. We hypothesized that lines placed in the operating room (OR) would have a lower infection rate due to established insertion protocols and a more sterile environment. Methods A retrospective chart review of NICU patients who received a percutaneous or tunneled central venous catheter between 2005 and 2012 was performed. ECMO cannulas, PICC and umbilical catheters were excluded. Variables of interest included demographics, anatomical site, hospital location, line days, and line infection. Line infection was defined as a positive blood culture drawn through the catheter. Results A total of 368 catheters were placed in 285 NICU patients. Majority of catheters (65.5%) were placed in OR. Saphenous and femoral veins were most common anatomical sites (50.8%). Twenty-eight catheters were infected (7.6%). After adjusting for preoperative antibiotics, anatomical site, and SNAPPE-II scores, lines placed in OR were three times less likely to become infected (Odds Ratio=0.32, p=0.038). Although implementation of CABSI prevention protocols resulted in statistically significant reductions in infection (Odds Ratio=0.4, p=0.043), lines placed in the OR remained less likely to become infected. Conclusions NICU line infection rates decreased with implementation of CABSI prevention protocols. Despite this implementation, catheters placed in the NICU continued to have higher infection rates. As a result, when patient status allows it, we recommend that central lines in newborns be placed in the operating room.

Objective: Artificial lungs may have a role in supporting patients with end-stage lung disease as a bridge or alternative to lung transplantation. This investigation was performed to determine the effect of an artificial lung, perfused by the right ventricle in parallel with the pulmonary circulation, on indices of right ventricular load in a model of pulmonary hypertension. Methods: Seven adult male sheep were connected to a low-resistance membrane oxygenator through conduits anastomosed end to side to the pulmonary artery and left atrium. Banding of the distal pulmonary artery generated acute pulmonary hypertension. Data were obtained with and without flow through the device conduits. Outcome measures of right ventricular load included hemodynamic parameters, as well as analysis of impedance, power consumption, wave reflections, cardiac efficiency, and the tension-time index. Results: The model of pulmonary hypertension increased all indices of right ventricular load and decreased ventricular efficiency. Allowing flow through the artificial lung significantly reduced mean pulmonary artery pressure, zero harmonic impedance, right ventricular power consumption, amplitude of reflected waves, and the tension-time index. Cardiac efficiency was significantly increased. Conclusions: An artificial lung perfused by the right ventricle and applied in parallel with the pulmonary circulation reduces ventricular load and improves cardiac efficiency in the setting of pulmonary hypertension. These data suggest that an artificial lung in this configuration may benefit patients with end-stage lung disease and pulmonary hypertension with right ventricular strain.

Liquid ventilation with perflubron is associated with reduced neutrophil recruitment into the lung during acute injury. Perflubron also reduces chemotactic responses, the respiratory burst, and cytokine production in neutrophils and in alveolar macrophages in vitro. In the current studies, the effect of perflubron on neutrophil chemotaxis to formyl-Met-Leu-Phe (fMLP) and phagocytosis of opsonized sheep erythrocytes (EA) correlated with decreased phosphorylation of Syk, an important intracellular second messenger in pathways regulating neutrophil functional responses. Brief (5 min) exposure of neutrophils to perflubron resulted in a dose-dependent reduction in chemotaxis to fMLP and reduced phagocytosis of EA but no apparent morphological changes as seen by electron microscopy. Concurrently, there was a reduction in both total cytosolic tyrosine phosphorylation and Syk phosphorylation. Binding studies indicated that this effect was neither a result of impaired ligand-receptor affinity nor a change in the number of fMLP receptors available on the neutrophil surface. These results suggest that perflubron nonspecifically affects cellular activation as measured by tyrosine phosphorylation perhaps by interfering with transmembrane signal transduction.

Background/Purpose: Pulmonary injury from mechanical ventilation has been attributed to application of excess alveolar pressure (barotrauma) or volume (volutrauma). The authors questioned whether partial liquid ventilation (gas ventilation of the perfluorocarbon filled lung, PLV) would reduce ventilator-induced lung injury. Methods: A tracheostomy tube and carotid artery catheter were placed in anesthetized Sprague-Dawley rats (500 ± 50 g). Bovine serum albumin (BSA) labeled with Iodine (I) 125 was administered intraarterially. Ventilation with tidal volume (TV) of 5 mL/kg was initiated. The rats were then selected randomly to a 30-minute experimental period of one of the following ventilation protocols: continued atraumatic gas ventilation (GV, TV, 5 mL/kg; n=10); atraumatic gas ventilation combined with intratracheal administration of 10 mL/kg perfluorocarbon (GV-PLV, TV, 5 mL/kg, n=10); barotrauma (BT, peak inspiratory pressure [PIP], 45 cm H 2 O; n=10); barotrauma with PLV (BT-PLV, PIP, 45 cm H 2 O; n=8); volutrauma (VT, TV, 30 mL/kg; n=8); or volutrauma with PLV (VT-PLV, TV, 30 mL/kg; n=10). Animals were killed and the amount of radiolabeled BSA in both lungs was measured and normalized to the counts in 1 mL of blood from that animal (injury index). Data were analyzed by analysis of variance (ANOVA) with post-hoc t test comparison between groups. Results: There was a significant difference in the 125 I-BSA injury index when all groups were compared ( P P =.024) and VT versus VT-PLV ( P =.014). Conclusion: 125 I-BSA leak produced during high-pressure or high-volume mechanical ventilation is reduced by partial liquid ventilation. J Pediatr Surg 36:1333-1336. Copyright © 2001 by W.B. Saunders Company.

Purpose: To evaluate a modified approach to a proctocolectomy for ulcerative colitis using a laparoscopy-assisted technique. Methods: Four 5-mm ports (epigastric, umbilical, and left and right lower quadrants) are used for colonic mobilization without ligation of the mesenteric vessels. A low suprapubic transverse incision is then made, and the colon is pulled out with sequential ligation of mesenteric vessels. The remainder of the endorectal dissection and pull-through is performed in a conventional manner. At the end of the procedure, the right lower quadrant port site is converted to an ileostomy. Results: Seven patients underwent this approach over 2 years. There were five girls, and the mean age was 10.3 ± 3.9 years. All operations were successfully performed, and the mean operating time was 8.5 ± 1.1 hours. The operative time decreased from 10 hours for the first case to 7.25 hours for the last case. The mean number of hospital days was 5.5 ± 0.5. There was one postoperative small-bowel obstruction,...

Background/Purpose: The authors have shown previously in an animal model that neonatal lung growth can be accelerated by continuous intrapulmonary distension with a perfluorocarbon (PFC). The authors now describe a preliminary clinical experience with this therapeutic concept in a select group of infants with congenital diaphragmatic hernia (CDH). Methods: Neonates with very high predicted mortality rate caused by CDH had their lungs completely filled with PFC while on extracorporeal life support (ECLS); (n = 5). A continuous positive pressure of 7 to 10 cm H 2 O was maintained via the endotracheal tube for 3 to 7 days (mean, 5.6 ± 0.87 days). The areas of both lungs (L) then were measured daily from digitized chest x-rays and divided by the area of the corresponding L1 vertebrae (V), to create an L/V index, so as to control for variable roentgenographic techniques. Immediately after removal of PFC, blood gas data were collected off ECLS. Results: At the end of continuous pulmonary distension, all patients showed improvements in oxygenation and ventilation. The ipsilateral lungs showed significant increase of the L/V index with time ( P =.003) and of L/V's daily change ( P Conclusions: Continuous intrapulmonary distension with PFC for up to 1 week accelerated ipsilateral lung growth, improved gas exchange, and increased survival of CDH infants with profound pulmonary hypoplasia marooned on ECLS. Additional trials of PFC-based pulmonary distension in similar infants are warranted. J Pediatr Surg 36:1237-1240. Copyright © 2001 by W.B. Saunders Company.

Background/Purpose: Appendicitis is the most common surgical emergency presenting in the pediatric population. Approximately one third of these patients present with equivocal signs and symptoms frequently resulting in inpatient observation or additional diagnostic investigation. Although sonographic examination of patients with suspected appendicitis has been shown to be a highly accurate diagnostic modality, the cost effectiveness of this technology in the pediatric population has not been addressed. The economic value of this examination can be evaluated using a structured decision analysis. Methods: The authors constructed a decision analysis model of treatment strategies for 2 groups of patients with a suspected diagnosis of acute appendicitis. Patients were categorized as either presenting with a "definitive acute abdomen" or "equivocal examination." Data drawn from published literature reports of the sensitivity and specificity of ultrasound, institution-specific cost data, and expert judgment were used to construct 2 decision trees. These data were used to determine the least costly diagnostic strategy for each group of patients, and sensitivity analysis performed to assess the robustness of the conclusions. Results: The use of ultrasonography in patients with "an acute abdomen" is not cost efficient and results in average additional cost of $234 per patient. In patients with equivocal diagnoses who are discharged from the emergency room after a negative ultrasound examination finding results in an average cost savings of $260 when compared with admission and observation. Patients who are discharged without examination incur an average additional cost of $373 as a result of the high cost of a missed diagnosis resulting in a perforated appendix. Conclusion: The use of ultrasonography can be recommended for children with suspected appendicitis and equivocal examinations who are discharged from the emergency room after a negative examination result. J Pediatr Surg 35:1236-1241. Copyright © 2000 by W.B. Saunders Company.

Oxygen transfer across a single cotyledon of the human placenta was assessed by using three different perfusates in the maternal circuit: 1) M-199 culture medium, 2) human adult red blood cells (RBCs), and 3) perflubron. These maternal circuit perfusates were oxygenated with a membrane oxygenator. RBCs were perfused on the fetal side of the circuit and samples were taken preplacenta and postplacenta for each maternal perfusate. PO2 and PCO2 were measured and O2 transfer was calculated for each maternal perfusate. O2 transfer per single cotyledon (mean +/- SE) was 0.18 +/- 0.04, 0.20 +/- 0.03, and 0.15 +/- 0.05 ccO2/min when using: 1) M-199, 2) RBCs, and 3) perflubron, respectively. O2 transfer per kilogram of placental tissue was 13.08 +/- 2.78, 14.57 +/- 2.05, and 10.43 +/- 3.79 ccO2/kg per minute when using: 1) M-199, 2) RBCs, and 3) perflubron, respectively. When extrapolated to the individual weights of the entire placenta, the O2 transfer was 9.15 +/- 1.95, 10.20 +/- 1.43, and 7.30 +/- 2.65 when using: 1) M-199, 2) RBCs, and 3) perflubron, respectively. We conclude from these data that O2 transfer can be accomplished during placental perfusion. Larger studies are required to differentiate efficacy among the three maternal circuit perfusates.

Objective: To determine whether the use of nitric oxide (NO)-releasing polymers coated onto the inner surface of extracorporeal circuits can reduce platelet consumption and activation in the absence of systemic heparinization using a rabbit model of veno-venous extracorporeal circulation. Design: Prospective, controlled trial Setting: Research laboratory at an academic medical institution. Subjects: New Zealand White Rabbits Interventions: Anesthetized, tracheotomized, and ventilated New Zealand White rabbits were injected with freshly prepared, 111 In(oxine) 3 labeled single donor platelets through the external jugular vein. After baseline measurements, these animals were placed on venovenous extracorporeal circulation through a 1-m control circuit or NO test circuit for 4 hrs at a blood flow rate of 109-118 mL/min via roller pump. Four groups were studied: systemically heparinized control circuits, systemically heparinized NO test circuits, nonheparinized control circuits, and nonheparinized NO test circuits. Platelet counts, fibrinogen levels, and plasma free indium levels were measured hourly. Circuits were rinsed and retained for gamma counting after the 4-hr run or when the circuit clotted. Four animals, one from each group, did not receive radiolabeled platelets so that the circuits could be preserved for scanning electron microscopic examination after the 4-hr study. Measurements and Main Results: Platelet consumption was significantly reduced in both the heparinized and nonheparinized NO test groups when compared with the controls (p

The aim of this study was to describe a single-center experience with pediatric extracorporeal life support (ECLS) and to determine variables predictive of outcome in pediatric patients, both before the institution of ECLS and while on support.From October 1985 to September 1998 the authors supported 128 children with severe acute hypoxemic respiratory failure(n = 121, Pao2/FIo2 ratio = 58+/-29) or acute hypercarbic respiratory failure (n = 7, Paco2 = 128+/-37), despite maximal conventional ventilation. Mode of access included venoarterial bypass (VA, n = 64), venovenous bypass (VV, n = 53), and VV to VA bypass (n = 11). The techniques used included lung rest, pulmonary physiotherapy, diuresis to dry weight using hemofiltration if needed, minimal anticoagulation, and optimal systemic oxygen delivery.The median age was 1.4 years (range, 2 weeks to 17 years). The mean duration of ECLS was 288+/-240 hours (range, 4 to 1148 hours or 0.2 to 47.8 days). Lung compliance increased from 0.32+/-0.02 mL/cm H2O/kg to 0.59+/-0.03 mL/cm H2O/kg in survivors, but only increased from 0.34+/-0.02 mL/cm H2O/kg to 0.35+/-0.02 mL/cm H2O/kg in nonsurvivors (P.002 comparing change between survivors and nonsurvivors). Mean body weight decreased from 9%+/-2% over dry weight to 4%+/-2% in survivors, whereas in nonsurvivors the mean body weight increased from 25%+/-5% over dry weight to 35%+/-7% (P.001). Outcome results by diagnosis were pneumonia, 73%; acute respiratory distress syndrome, 67%; and airway support, 60%, with overall lung recovery occurring in 77%, and hospital survival in 71%. Multivariate logistic regression modelling of patients with hypoxemic respiratory failure found the only pre-ECLS variable significantly associated with outcome to be pH (P.05). Variables during the course of ECLS significantly associated with decreased survival were the presence of creatinine greater than 3.0 (P.01), the need for inotropes (P.04), failure to return the patient to dry weight (P.04), and lung compliance that did not improve significantly. (P.01).ECLS provides life support in severe respiratory failure in children, allowing time for injured lungs to recover. Pre-ECLS predictors, such as pH and variables during ECLS, such as presence of renal failure, improvement in compliance, return to dry weight, and the need for inotropes on ECLS, may be useful for predicting outcome.

The introduction of managed care in the 1980s caused increased pressure to reduce costs for hospitalized patients. The authors hypothesized that these market forces have resulted in a decreased hospital stay and utilization of sophisticated diagnostic testing in children treated for appendicitis. If true, the impact of this paradigm shift on patient outcome is unknown.Hospital records for 913 pediatric patients treated for appendicitis from 1974 to 1998 were reviewed retrospectively. Patients were stratified into those with perforated appendicitis (PA) and nonperforated appendicitis (NPA). Demographics, perioperative hospital course, diagnostic testing, complications, and long-term outcomes were analyzed after stratification into time intervals.Over time, children with NPA were treated with shorter antibiotic courses (P.05) and were placed on a regular diet earlier (P.05). These changes in treatment resulted in an earlier discharge (P.05). The amount of time to become afebrile with a normal white blood cell count (WBC) did not change over time. Children with PA exhibited similar results with shorter antibiotic courses (P.05), earlier dietary intake (P.05) and earlier hospital discharge (P.05) over time. In all children with appendicitis there was no significant difference in the rate of wound infections, abscesses requiring drains, readmission, or reoperations overtime. The utilization of abdominal radiographs (83%) and ultrasonography (USN; 40%) was high and remained unchanged over time. Utilization of computed tomography (CT scan) was low (4.3%) in the early decades and was not used as a preoperative test from 1991 to 1994. Given the high diagnostic accuracy of a pediatric surgeon for this disease, Bayesian analysis indicates that USN utilization rates should be 15%.The market pressures of managed care have resulted in a new treatment paradigm with an earlier discharge of all children with appendicitis. There has been no concomitant increase in the complication rate in either group as a result of this paradigm shift. Bayesian analysis indicates that USN and abdominal radiographs are overutilized in our institution.

A number of advances in the treatment of infants and children with respiratory failure have been investigated in the laboratory with translation to clinical practice. Investigators have recognized that application of high ventilating pressures and failure to apply adequate levels of positive end-expiratory pressure (PEEP) can inflict injury to the already failing lung. Other interventions such as prone positioning and application of new ventilating strategies such as proportional assist ventilation (PAV), inverse ratio ventilation (IRV), high frequency ventilation, liquid ventilation, and intratracheal pulmonary ventilation (ITPV), continue to be developed and explored. Administration of inhaled nitric oxide (iNO) may improve pulmonary physiology and gas exchange in patients with respiratory insufficiency. Finally, the technique of extracorporeal life support (ECLS) is being simplified and refined. This report summarizes the status of these advances and describes the basic science and clinical research that brought them to clinical application.

Purpose: The aim of this study was to assess the utility of technetium (Tc) 99m pertechnetate scintigraphy in the diagnostic workup of the pediatric patient with gastrointestinal (GI) bleeding and a suspected Meckel's diverticulum. Methods: The charts of 235 consecutive patients evaluated with a Meckel's scan (n = 165) or with the discharge diagnosis of Meckel's diverticulum (n = 70) between January 1975 and October 1997 were reviewed for presenting symptoms, bleeding characteristics, diagnostic studies and pathological diagnosis. Those patients with lower GI bleeding and a serum hemoglobin level less than 11.0 g/dL who underwent a 99m Tc pertechnetate scan (n = 43) were assessed for utility of the scan. Results: In all patients the Meckel's scan had a positive and negative predictive value of 0.93. However, in patients with lower GI bleeding and a hemoglobin less than 11.0 g/dL the Meckel's scan had a sensitivity of 0.60, a positive predictive value of 1.0, a specificity of 0.96, but only a negative predictive value of 0.74. As such, the probability that a child who presents with GI bleeding and a serum hemoglobin less than 11 g/dL will have a Meckel's diverticulum despite a negative Meckel's scan of 0.26. We further evaluated the eight patients with a false-negative scan: ectopic gastric mucosa was present on pathological examination in all eight patients. Pentagastrin stimulation was performed at the time of scintigraphic study in three of eight. Six of these eight patients had duplicate scans that also were negative. Patients with a false-negative (FN) scan had significantly increased hospital charges when compared with those with a true positive (TP) scan (TP = $5012 ± 1992; FN=$8554 ± 1506; P = .0001). Clinical suspicion had a major effect on the decision-making process in these patients independent of the results of the Meckel's scan, and all eight patients ultimately underwent exploratory laparoscopy-laparotomy with Meckel's diverticulectomy despite the scan results. Conclusions: The relatively low negative predictive value of the Meckel's scan may result in the need for operative evaluation despite the scan data. As such, the contribution of the scan to clinical decision making is low. These findings suggest that exploratory laparotomy or laparoscopy may be indicated instead of scintigraphic scanning in the assessment of the anemic (hemoglobin less than 11 g/dL) pediatric patient with lower GI bleeding, especially in patients in whom a high suspicion for a bleeding Meckel's diverticulum exists.