Sonography, CT, and MR imaging: a prospective comparison of neonates with suspected intracranial ischemia and hemorrhage.

BACKGROUND AND PURPOSE: Sonography, CT, and MR imaging are commonly used to screen for neonatal intracranial ischemia and hemorrhage, yet few studies have attempted to determine which imaging technique is best suited for this purpose. The goals of this study were to compare sonography with CT and MR imaging prospectively for the detection of intracranial ischemia or hemorrhage and to determine the prognostic value(s) of neuroimaging in neonates suspected of having hypoxic-ischemic injury (HII). METHODS: Forty-seven neonates underwent CT (n = 26) or MR imaging (n = 24) or both (n = 3) within the first month of life for suspected HII. Sonography was performed according to research protocol within an average of 14.4 +/- 9.6 hours of CT or MR imaging. A kappa analysis of interobserver agreement was conducted using three independent observers. Infants underwent neurodevelopmental assessment at ages 2 months (n = 47) and 2 years (n = 26). RESULTS: CT and MR imaging had significantly higher interobserver agreement (P < .001) for cortical HII and germinal matrix hemorrhage (GMH) (Grades I and II) compared with sonography. MR imaging and CT revealed 25 instances of HII compared with 13 identified by sonography. MR imaging and CT also revealed 10 instances of intraparenchymal hemorrhage (>1 cm, including Grade IV GMH) compared with sonography, which depicted five. The negative predictive values of neuroimaging, irrespective of technique used, were 53.3% and 58.8% at the 2-month and 2-year follow-up examinations, respectively. CONCLUSION: CT and MR imaging have significantly better interobserver agreement for cortical HII and GMH/intraventricular hemorrhage and can reveal more instances of intraparenchymal hemorrhage compared with sonography. The absence of neuroimaging findings on sonograms, CT scans, or MR images does not rule out later neurologic dysfunction.

Response of premature infants with severe respiratory failure to inhaled nitric oxide. Preemie NO Collaborative Group.

Elevated pulmonary vascular resistance is seen in premature infants with severe respiratory distress syndrome (RDS). Inhaled nitric oxide (NO) has been shown to decrease pulmonary vascular resistance and to improve oxygenation in some patients with respiratory failure. The purpose of this study was to determine whether premature infants with severe RDS would respond to inhaled NO with an improvement in oxygenation. Eleven premature infants (mean gestational age 29.8 weeks) with severe respiratory failure caused by RDS were treated with NO in four concentrations [1, 5, 10, 20 parts per million (ppm) NO] and with placebo (0 ppm NO). Arterial blood gas measurements were drawn immediately before and at the end of each of the 15-minute treatments and were used to determine the arterial/alveolar oxygen ratio (PaO2/PAO2). Ten of the 11 infants had a greater than 25% increase in PaO2/PAO2. Five of the 11 had a greater than 50% increase in PaO2/PAO2. Despite normal cranial ultrasound imaging prior to NO, 3 infants had intracranial hemorrhage (ICH) noted on their first ultrasound scan after this brief period of NO treatment, and 4 additional infants developed ICH later during their hospitalization. No infant had significant elevations of methemoglobin concentrations after the total 60-minute exposure to NO. NO may be an effective method of improving oxygenation in infants with severe RDS. The disturbing incidence of ICH in this small group of infants needs to be carefully evaluated before considering routine use or NO for preterm infants.

Zero-order controlled-release polymer matrices for micro- and macromolecules.

Theoretical and experimental analyses demonstrate that a hemispheric polymer-drug matrix laminated with an impermeable coating, except for an exposed cavity in the center face, can be used to achieve zero-order release kinetics. Hemispheric systems for low molecular weight drugs were prepared by heating and compressing polyethylene and drug (sodium salicylate) in a brass mold. Hemispheric systems for high molecular weight drugs were prepared by casting ethylene-vinyl acetate copolymer and protein in a hemispheric mold at -80 degrees, followed by a two-step drying procedure (-20 and 20 degrees). In both systems, cavities were made in the center face of the hemispheres and the remainder of the matrices coated with an impermeable material. Zero-order release for 60 days at a rate of 0.5 mg/day was achieved from polymer matrices containing bovine serum albumin (mol. wt. 68,000).

Polymers for sustained macromolecule release: procedures to fabricate reproducible delivery systems and control release kinetics.

Matrixes composed of ethylene-vinyl acetate copolymer are useful vehicles for the sustained release of macromolecules such as proteins. A new procedure for fabricating these polymeric delivery systems involved mixing the dry, powdered macromolecule with a polymer solution and casting the mixture at -80 degrees. The resulting matrix was dried in two 48-hr stages, first at -20 degress and then at 20 degrees. These polymer systems had uniform drug distribution, and their release kinetics were reproducible. Fabrication parameters such as drug particle size, drug loading, and matrix coating all significantly affected release kinetics.

Secondary infection presenting as recurrent pulmonary hypertension.

Primary infection in the neonate, especially group B streptococcal infection, has long been recognized as a cause of persistent pulmonary hypertension of the newborn (PPHN), sometimes requiring treatment with inhaled nitric oxide (iNO) and extracorporeal membrane oxygenation (ECMO). However, secondary nosocomial infections in the neonatal period have not been widely reported as a cause of severe recurrent pulmonary hypertension (PHTN). We now present two cases of secondary infection in the neonate leading to significant PHTN. In both cases, the infants presented with PPHN soon after birth, requiring transfer to a level 3 neonatal intensive care unit and treatment with high-frequency oscillatory ventilation and iNO. After successful resolution of the initial PPHN, including extubation to nasal cannula, both infants developed signs of severe recurrent PHTN, leading to reintubation, high-frequency oscillatory ventilation and iNO therapy, and consideration of ECMO. In both cases, blood cultures taken at the time of recurrence of PHTN returned positive, one for Staphylococcus epidermidis, the other for methicillin-resistant Staphylococcus aureus. These unusual cases present the possibility of severe recurrent PHTN requiring iNO or ECMO in the setting of secondary infection. We speculate that these infants, although extubated after their first episodes of PHTN, were at risk for recurrence of PHTN due to continued pulmonary vascular reactivity.

Hemopericardium from coronary artery laceration complicating extracorporeal membrane oxygenation.

OBJECTIVE: We report the clinical course and successful surgical treatment of hemopericardium resulting from coronary artery (CA) laceration in two patients with congenital diaphragmatic hernia (CDH) undergoing extracorporeal membrane oxygenation (ECMO) bypass. STUDY DESIGN: Retrospective case review. RESULTS: Two neonates with CDH had needle aspiration for either pneumothorax or pericardial effusion before initiation of ECMO. While on bypass, progressive hemopericardium led to narrow pulse pressure and decreased venous return that limited bypass flow. Widened cardiac silhouette on chest radiographs suggested hemopericardium; echocardiography was confirmatory in one case. The underlying diagnosis of CA laceration was made during pericardiotomy and treated with surgical patching. CONCLUSIONS: Pre-ECMO history of cardiothoracic needle aspiration is important because complications such as hemothorax or hemopericardium may arise once ECMO bypass is initiated. Inadvertent CA laceration may lead to acute hemopericardium, compromising venous drainage. However, CA laceration can be successfully repaired while the patient is on bypass.

Nitrovasodilator therapy for severe respiratory distress syndrome.

Improved gas exchange in infants with severe respiratory distress syndrome has been reported in association with infusion of nitroprusside and during inhalation of nitric oxide. To evaluate the association between nitrovasodilator therapy and clinical improvement in premature neonates with severe respiratory distress syndrome, we reviewed the courses of 22 infants with severe respiratory distress syndrome who were treated with sodium nitroprusside for at least 24 hours. These infants had birth weights of 2049 +/- 828 gm (range 720 to 3430 gm), gestational ages of 32.5 +/- 3.5 weeks (range 25 to 38 weeks), high ventilator settings before treatment (FIO2 of 100%, peak inspiratory pressures of 37.8 +/- 6.1 cm H2O [range 30 to 50 cm H2O], and mean airway pressures of 18.0 +/- 3.3 cm H2O [range 12.3 to 26 cm H2O]), and low pretreatment PaO2 of 49.3 +/- 9.4 mm Hg (range 27 to 69 mm Hg). Baseline oxygenation indexes were 39.4 +/- 12.1 (range 18.6 to 66.7). Nitroprusside infusion was temporally associated with increased PaO2, decreased PaCO2, and reduced oxygenation index. Potentially beneficial changes were inconsistent in infants with pulmonary interstitial emphysema and were greatest in infants treated with end-expiratory pressures of at least 4 cm H2O. These observations provide a basis for the hypothesis that nitrovasodilator therapy produces improvement in gas exchange in premature infants with severe respiratory distress syndrome.

Bilirubin toxicity and differentiation of cultured astrocytes.

OBJECTIVE: To study the toxicity of bilirubin in primary cultures of newborn rat cerebral cortical astrocytes. STUDY DESIGN: Primary cultures of newborn rat astrocytes were incubated at bilirubin concentrations of 0, 1, 5, 10, 25, 50, 100, 200, and 2000 microM, at a bilirubin:albumin molar ratio of 1.7. Bilirubin toxicity was determined by changes in cellular morphology, trypan blue staining, and lactate dehydrogenase (LDH) release into the culture medium at various times of incubation. To determine if differentiation of astrocytes affects bilirubin toxicity, cultures were treated with dibutyryl cyclic adenosine monophosphate. RESULTS: All three indices of toxicity showed a bilirubin concentration dependence. LDH release in experimental cultures was significantly elevated (p < 0.05) above that of control cultures by 24 hours at bilirubin concentrations of > or = 100 microM. The absolute amount of LDH release differed significantly between the 200 and 2000 microM cultures from 1.5 to 24 hours, after which duration of exposure appeared to take over and all cultures approached maximum. LDH release for the lower concentrations all reached maximum by 120 hours, except for the 1 microM cultures, which showed no significant elevation above control throughout the study period. At 100 and 200 microM bilirubin, LDH release by untreated cells was significantly higher (p < 0.05) than release by treated cells by 36 hours. CONCLUSION: Undifferentiated astrocytes appeared to be more sensitive to bilirubin toxicity, which may correlate with the greater susceptibility of newborns to kernicteric injury. Studies with primary astrocyte culture may provide insight into how bilirubin sensitivity changes with brain development as well as the cellular and biochemical mechanisms of bilirubin encephalopathy.

Fatal postoperative Legionella pneumonia in a newborn.

This is a case of postoperative Legionella pneumonia in a full-term infant with hypoplastic left heart syndrome. The infant had an uncomplicated prenatal history, normal vaginal delivery, Apgars of 8 at 1 and 5 minutes, but was cyanotic at birth. At 3 days of age she had a stage 1 Norwood surgical procedure to palliate her congenital heart disease. A synthetic patch was placed over the thoracic midline because of difficulty in reapposing the sternum. Peritoneal dialysis was used to manage renal failure. At 20 days of age she had disseminated intravascular coagulopathy and pneumonia associated with sepsis. Four days later she died. Legionella pneumophila serogroup 1 was isolated from a lung culture taken at autopsy.

Congenital diaphragmatic hernia associated with aortic coarctation.

Congenital diaphragmatic hernia (CDH) may be associated with other anomalies, most frequently cardiovascular in nature. Despite fetal echocardiography, diagnosis of an accompanying cardiac malformation often is not made until after birth and sometimes not until after extracorporeal membrane oxygenation (ECMO) has been instituted. Aortic coarctation associated with CDH may occur as an isolated, surgically correctable malformation or it may be a component of the usually fatal left heart "hypoplasia" or "smallness" syndrome. The authors present two cases of aortic coarctation associated with CDH requiring ECMO that illustrate the management challenges of these coincident diagnosis. In one case, the accompanying coarctation was suspected and required precannulation angiography for confirmation, whereas in the other case, the diagnosis of coarctation was not made until after ECMO cannulation. Depending on its anatomic location and severity, an aortic coarctation associated with life-threatening CDH may limit the physiological efficacy of venoarterial ECMO. Furthermore, arterial cannulation for extracorporeal support requires that flow through the remaining carotid artery be maintained during aortic reconstruction, which may prove difficult for lesions best treated by subclavian flap angioplasty. When the diagnosis of coincident aortic coarctation and CDH is suspected or proven before institution of extracorporeal support, serious consideration should be given to venovenous bypass, because this may provide better postductal oxygenation and facilitate aortic repair with the option of left carotid artery inflow occlusion.

Lobar lung transplantation as a treatment for congenital diaphragmatic hernia.

The mortality rate for infants severely affected with congenital diaphragmatic hernia (CDH) remains high despite significant advances in surgical and neonatal intensive care including delayed repair and extracorporeal membrane oxygenation (ECMO). Because of the increasingly successful experience with single-lung transplantation in adults; this approach has been suggested as a potential treatment for CDH infants with unsalvageable pulmonary hypoplasia. The authors report on a newborn female infant who was the product of a pregnancy complicated by polyhydramnios. At birth, she was found to have a right-sided CDH and initially was treated with preoperative ECMO, followed by delayed surgical repair. Despite the CDH repair and apparent resolution of pulmonary hypertension, the infant's condition deteriorated gradually after decannulation, and escalating ventilator settings were required as well as neuromuscular paralysis and pressor support because of progressive hypoxemia and hypercarbia. A lung transplant was performed 8 days after decannulation, using the right lung obtained from a 6-week-old donor. The right middle lobe was excised because of the size discrepancy between the donor and recipient. After transplantation, the patient was found to have duodenal stenosis and gastroesophageal reflux, which required duodenoduodenostomy and fundoplication. The patient was discharged from the hospital 90 days posttransplantation, at 3 1/2 months of age. Currently she is 24 months old and doing well except for poor growth. This case shows the feasibility of single-lung transplantation for infants with CDH, and the potential use of ECMO as a temporary bridge to transplantation. Lobar lung transplantation allowed for less stringent size constraints for the donor lung.

Venoarterial versus venovenous extracorporeal membrane oxygenation in congenital diaphragmatic hernia: the Extracorporeal Life Support Organization Registry, 1990-1999.

BACKGROUND/PURPOSE: Venoarterial (VA) extracorporeal membrane oxygenation (ECMO) traditionally has been the mode of support used in congenital diaphragmatic hernia (CDH). A few studies report success using venovenous (VV) ECMO. The purpose of this study is to compare outcomes in CDH patients treated with VA and VV. METHODS: The authors queried the Extracorporeal Life Support Organization Registry for newborns with CDH treated with ECMO from January 1, 1990 through December 31, 1999. They analyzed the pre-ECMO data, ECMO course, and complications. RESULTS: VA was utilized in 2,257 (86%) and VV in 371 (14%) patients. The pre-ECMO status was similar, with greater use of nitric oxide, surfactant, and pressors in VV. Survival rate was similar (58.4% for VV and 52.2% for VA, P =.057). VA was associated with more seizures (12.3% v 6.7%, P =.0024) and cerebral infarction (10.5% v 6.7%, P =.03). Sixty-four treatments were converted from VV to VA (VV-->VA). Survival rate in VV-->VA was not significantly different than VA (43.8% v 52.2%, respectively; P =.23). VV-->VA and VA patients had similar neurologic complications. CONCLUSIONS: CDH patients treated with VV and VA have similar survival rates. VA had more neurologic complications. The authors identified no disadvantage to the use of VV as an initial mode of ECMO for CDH, although some infants may need conversion to VA.

Schistosoma mansoni: reproductive potential of male and female worms cultured in vitro.

We studied the development of S. mansoni after various combinations of ex-vivo, cultured, and unisexual male and female worms were implanted into hamsters. Females of any type, co-implanted with ex-vivo males, were capable of developing to maturity and producing eggs containing viable miracidia. Cultured males often did not induce adequate growth and maturation of females, but viable miracidia were produced in some animals co-implanted with cultured males plus cultured, ex-vivo, or unisexual females. We concluded that both cultured males and females have the potential for full growth and reproductive maturation, but are retarded in vitro by inadequate culture conditions.

Where should the hemofiltration circuit be placed in relation to the extracorporeal membrane oxygenation circuit?

Patients requiring extracorporeal membrane oxygenation (ECMO) frequently experience hypervolemia and metabolic abnormalities that can be effectively managed by hemofiltration. Although several options for hemofiltration circuit placement exist, some may have the disadvantage of recirculation or shunting of poorly oxygenated blood to the patient. Attachment of the entire hemofiltration circuit to the pre-ECMO pump region is described. Despite the absence of pump generated pressure and a low blood flow rate, effective hemofiltration and diafiltration were achieved. This article examines whether placement of the hemofiltration circuit proximal to the ECMO pump has advantages over other hemofiltration circuit placements.

Neonatal aspergillosis. A case report and review of the literature.

Neonatal aspergillosis is a rare, usually overwhelming multisystem infection diagnosed postmortem. We present a neonate who had a brain abscess diagnosed by CT scan that was found at surgical exploration to contain aspergillus. Treatment included prolonged antifungal medication and several surgical interventions. The child has neurologic sequelae, including a seizure disorder and hemiplegia. There are no previously reported survivors of neonatal aspergillosis.

Combining hand techniques with electric pumping increases the caloric content of milk in mothers of preterm infants.

OBJECTIVE: We previously reported that preterm mothers' milk production can exceed levels of term mothers by using early hand expression and hands-on pumping (HOP) with the highest production (955 ml per day) in frequent users of hand expression. In this study, we compared milk composition between mothers stratified by early hand expression frequency. STUDY DESIGN: A total of 67 mothers of infants <31 weeks gestation were instructed on hand expression and HOP. Subjects submitted expression records and 1-ml samples from each pumping session over 24 h once weekly for 8 weeks. RESULT: 78% (52/67) of mothers completed the study. But for Week 1, no compositional differences (despite production differences) were noted between the three groups. Protein and lactose tracked reported norms, but fat and energy of mature milk (Weeks 2-8) exceeded norms, 62.5 g l(-1) per fat and 892.7 cal l(-1) (26.4 cal oz(-1)), respectively. CONCLUSION: Mothers combining manual techniques with pumping express high levels of fat-rich, calorie-dense milk, unrelated to production differences.

Improved outcomes with a standardized feeding protocol for very low birth weight infants.

OBJECTIVE: The objective of this study was to evaluate the impact of a standardized enteral feeding protocol for very low birth weight (VLBW) infants on nutritional, clinical and growth outcomes. STUDY DESIGN: Retrospective analysis of VLBW cohorts 9 months before and after initiation of a standardized feeding protocol consisting of 6-8 days of trophic feedings, followed by an increase of 20 ml/kg/day. The primary outcome was days to reach full enteral feeds defined as 160 ml/kg/day. Secondary outcomes included rates of necrotizing enterocolitis and culture-proven sepsis, days of parenteral nutrition and growth end points. RESULT: Data were analyzed on 147 VLBW infants who received enteral feedings, 83 before ('Before') and 64 subsequent to ('After') feeding protocol initiation. Extremely low birth weight (ELBW) infants in the After group attained enteral volumes of 120 ml/kg/day (43.9 days Before vs 32.8 days After, P=0.02) and 160 ml/kg/day (48.5 days Before vs 35.8 days After, P=0.02) significantly faster and received significantly fewer days of parenteral nutrition (46.2 days Before vs 31.3 days After, P=0.01). Necrotizing enterocolitis decreased in the After group among VLBW (15/83, 18% Before vs 2/64, 3% After, P=0.005) and ELBW infants (11/31, 35% Before vs 2/26, 8% After, P=0.01). Late-onset sepsis decreased significantly in the After group (26/83, 31% Before vs 6/64, 9% After, P=0.001). Excluding those with weight <3rd percentile at birth, the proportion with weight <3rd percentile at discharge decreased significantly after protocol initiation (35% Before vs 17% After, P=0.03). CONCLUSION: These data suggest that implementation of a standardized feeding protocol for VLBW infants results in earlier successful enteral feeding without increased rates of major morbidities.