A randomized, double-blind, placebo-controlled trial of prophylactic recombinant human granulocyte-macrophage colony-stimulating factor to reduce nosocomial infections in very low birth weight neonates.

OBJECTIVE: We carried out a randomized placebo-controlled trial in very low birth weight neonates (VLBWNs), comparing the incidence of nosocomial infections after the prophylactic use of recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF) versus placebo in VLBWNs. STUDY DESIGN: VLBWNs (n = 264), weighing 501 to 1000 g, /=4000/mm,3 peripheral blood progenitor studies, and 24-hour polymorphonuclear leukocyte C3bi receptor expression were compared between the 2 treatment groups. RESULTS: No (grade III/IV) toxicity or adverse events were associated with rhu GM-CSF. The absolute neutrophil count and absolute eosinophil count were significantly elevated in the rhu GM-CSF group on days 7 (P =.001), 14 (P =.001), and 21 (P =.007) and on days 7 and 28 (P =.012 and P =.001, respectively). However, there was no difference in the incidence of confirmed nosocomial infections between the 2 treatment groups in this trial (40% vs 39%, rhu GM-CSF vs placebo; P = NS). CONCLUSION: In a large randomized placebo-controlled trial, prophylactic administration of rhu GM-CSF in VLBWNs does not appear to decrease the incidence of nosocomial infections.

Serum cortisol levels in very low birth weight infants of substance-abusing mothers.

OBJECTIVE: Recently, hypoadrenalism was described in extremely low birth weight infants. We have been measuring serum cortisol levels in very low birth weight (VLBW) infants to assess their adrenal function. It was noticed that infants of substance-abusing mothers (ISAM) had unusually high serum cortisol levels. To our knowledge, there are no data regarding serum cortisol levels in VLBW ISAM. The objective of our study was to determine if serum cortisol levels of VLBW ISAM are different from serum cortisol levels in VLBW infants without a history of maternal substance abuse. METHODS: We reviewed medical records of infants with birth weight between 400 and 1300 gm who were born between July 1994 and June 1995. Seven ISAM who had serum cortisol levels drawn before 48 hours of life were identified. Seven infants matched for gestational age, antenatal steroid exposure, and birth weight served as control infants. Clinical characteristics, serum cortisol levels, and clinical outcome were compared between the two groups. Serum cortisol levels of all infants were measured by radioimmunoassay. RESULTS: The mean birth weight of the ISAM group was 834 gm (range 480 to 1175 gm), and the mean gestational age was 27.4 weeks. The mean birth weight of the control group was 921 gm (range 525 to 1230 gm) with a mean gestational age of 27.8 weeks. The mean serum cortisol level of the ISAM group was 65.3 micrograms/dl (range 11.9 to 144 micrograms/dl); it was significantly higher than that of the control group (mean cortisol level of 20.5 micrograms/dl; range 4.9 to 62.7 micrograms/dl) (p = 0.01, two-tailed). CONCLUSION: Our data suggest that maternal substance abuse significantly increases serum cortisol levels in VLBW infants. Studies in larger scale are needed to confirm our findings and to correlate cortisol levels in this group of patients with clinical outcome.

Low serum cortisol in term newborns with refractory hypotension.

OBJECTIVES: The aim of this study is to measure baseline serum cortisol levels and clinical response to glucocorticoid therapy in a group of term infants with refractory hypotension. STUDY DESIGN: Seven term newborns with refractory hypotension were included. Serum cortisol levels were drawn before initiation of glucocorticoid therapy and measured by either fluorescence polarization immunoassay or radioimmunoassay. Baseline blood pressures, heart rate, and inotropes doses were recorded at baseline, then 4, 8, 12, 24, 48, 72, and 96 hours after glucocorticoid therapy. Urine output and volume expanders the infants received were recorded 24 hours before and after glucocorticoid therapy. Dexamethasone was used at a starting dose of 0.2 mg/kg per day divided every 12 hours. The statistical analysis was done using analysis of variance with repeated measures and paired t-test. RESULTS: Serum cortisol levels of the infants ranged from 2.0 to 15.4 micrograms/dl. After initiation of glucocorticoid therapy, there was significant improvement of blood pressure. Vasopressors were rapidly weaned and discontinued within 72 hours. In three of seven infants, no volume expanders were required after initiation of steroids, and none needed volume expanders after 2 days. Urine output increased significantly within 24 hours. All infants survived. CONCLUSIONS: Glucocorticoids improved pressure and stabilized clinical conditions of a group of term newborns with refractory hypotension. Serum cortisol levels of these infants were relatively low. We speculate that a subset of critically ill term infants has relative adrenal insufficiency and glucocorticoid therapy may be essential.

Very low birth weight infants and their families during the first year of life: comparisons of medical outcomes based on after care services.

OBJECTIVE: To evaluate factors contributing to optimal medical outcomes during the first year following discharge of very low birth weight infants from tertiary neonatal intensive care units. STUDY DESIGN: This was a prospective investigation of the health and development of 81 very low birth weight infants following discharge from two tertiary neonatal intensive care units in Los Angeles. Infants were assigned to four groups receiving a variety of after care services in their homes. Analyses of variance were computed to examine differences between groups for a variety of outcomes. RESULTS: No statistically significant differences were seen between after care groups on use of hospital emergency rooms (ER) rehospitalization rates, or child abuse and neglect. Highest overall rates of optimal outcomes were seen in the group receiving the highest intensity of after care services. Those groups receiving long-term home visiting services had significantly higher rates of up-to-date immunizations. CONCLUSION: There was no significant impact on infant mortality and morbidity of early discharge, regardless of the system of after care used. However, those infants who received the highest level of after care services had the most optimal health outcomes and were most likely to be receiving well-baby care. It is likely that the comprehensive, clinic-based system of health care available to all study infants was a significant factor in low rates of morbidity.

Very low birth weight infants and their families during the first year of life: comparisons of psychosocial outcomes based on after-care services.

OBJECTIVE: To evaluate psychosocial outcomes in families of very low birth weight infants during the first year postdischarge. STUDY DESIGN: This was a prospective investigation of family functioning in families of 81 very low birth weight infants discharged from two tertiary care neonatal intensive care units in Los Angeles, CA. Infants were assigned to four groups receiving a variety of after-care services in their homes. Analyses of variance and t-tests were used to examine differences in outcomes, including parental involvement with infant, maternal depression, and family adaptation and cohesion over time. RESULTS: During the first year following discharge, there were no differences between after-care groups in levels of maternal depression as measured by the Center for Epidemiologic Studies Depression Scale or family cohesion and adaptability as measured by the Family Adaptability and Cohesion Evaluation Scales II. Significant between-group differences were seen on measures of home environment at both 6 and 12 months and self-reports of satisfaction with parenting at 6 months. CONCLUSION: Results of this study indicate that types of after-care services do not change basic maternal or family characteristics. However, long-term home-visiting services appear to impact the way mothers interact with their high-risk infants. Furthermore, such services seem to influence a mother's perception of satisfaction with her role.

The effects of IL-10 on proinflammatory cytokine expression (IL-1beta and IL-8) in hyaline membrane disease (HMD).

Deficient expression of the counterregulatory cytokine IL-10 by lung inflammatory cells may facilitate chronic inflammation and the pathogenesis of hyaline membrane disease (HMD), in premature infants. To determine if pathways which regulate proinflammatory cytokines in response to human recombinant IL-10 (rIL-10) were functional in the lungs of these neonates, bronchoalveolar lavage (BAL)-derived lung inflammatory cells (predominantly macrophages and neutrophils) from infants with HMD were cultured in the presence of lipopolysaccharide (LPS) and increasing concentrations of (rIL-10). The expression of IL-1beta and IL-8 protein was assessed 24 h later. IL-10 protein was also measured from the BAL aspirates of these newborns at 4-day intervals over the first month of life. In cell culture IL-1beta expression was inhibited by rIL-10 in a dose-dependent fashion while IL-8 expression was inhibited by higher concentrations of rIL-10. IL-10 protein was undetectable from BAL fluid of the premature infants sampled over 28 days. The results demonstrate that lung inflammatory cells, which do not express IL-10 in vivo, are capable of responding to rIL-10 in cell culture with reduction of IL-1beta and IL-8 expression. These data support the rationale for the development of rIL-10 as a potential anti-inflammatory agent in the treatment of HMD.

Subgaleal hemorrhage in a premature infant with congenital diaphragmatic hernia following vacuum-assisted delivery.

An infant with congenital diaphragmatic hernia was delivered by vacuum extraction, with a resultant subgaleal hemorrhage that excluded him from ECMO. The literature regarding vacuum-assisted delivery and birth trauma is reviewed in the context of congenital anomalies that may require ECMO support, and recommendations for perinatal management are suggested.

C-reactive protein levels in the extremely premature infant: case studies and literature review.

Sepsis continues to be a significant source of morbidity and mortality in the neonatal intensive unit. At the same time, we need to contain medical costs and prevent the rapid growth of resistant organisms by limiting unnecessary antibiotic use. Among laboratory indexes studied as indirect indicators of the presence and resolution of infection and inflammation, C-reactive protein (CRP) has gained more recent widespread use. CRP usually increases in a delayed manner with the onset of inflammation and decreases as inflammation resolves. We follow serial CRP values in our neonatal intensive care unit from the start of a sepsis evaluation until antibiotic therapy is withdrawn. We describe two extremely low birth weight patients who improved clinically with therapy and whose CRP levels normalized in the face of continued positive blood cultures. The implications for the use of CRP in deciding when to halt therapy in premature infants are discussed.

Structure of the human Nkx2.1 gene.

NKX2.1 is a member of the NK2 family of homeodomain-containing transcriptional factors which binds to and activates the promoters of thyroid and pulmonary epithelial genes. We have cloned and sequenced twelve human lung NKx2.1 cDNAs. To elucidate the origin of Nkx2.1 transcripts, we also cloned and sequenced a 12 kb human Nkx2.1 genomic clone. Alignment of cDNA sequences with the genomic clone showed that contrary to previous reports, the human Nkx2.1 gene is organized into three exons and two introns. The newly discovered exon I contains an ATG codon that falls in frame with the previously identified Nkx2.1 initiator ATG codon on one of the cDNAs, designated 5E. Northern blot analysis shows that an mRNA of approximately 2.5 kb in size, homologous to 5E, is expressed in both lung and thyroid. The deduced amino acid sequence of the longest open reading frame on 5E is identical to NKX2.1 with the exception of a 30 amino acid N-terminal extension. Coupled in vitro transcription/translation of the 5E cDNA confirms that the open reading frame is translated into a contiguous polypeptide of 44 kDa. Analysis of Nkx2.1 genomic DNA fragments suggest that at least two independent regions, one within the first intron and the other 5' of the first exon may mediate the basal promoter activity of the Nkx2.1 gene in lung epithelial cells.

Differential regulation of IL-8 by IL-1beta and TNFalpha in hyaline membrane disease.

Mechanisms that regulate cytokine-mediated inflammation in the lungs of preterm infants, including factors which regulate production of the chemokine IL-8, remain poorly defined. Sequential bronchoalveolar lavage samples were obtained from preterm newborns with hyaline membrane disease over a 28-day period. Bronchoalveolar lavage cell cytokine relationships were evaluated and the differential regulation of IL-8 by IL-1beta and TNFalpha was studied in a short-term culture system. In vivo, IL-8 and IL-1beta protein levels correlated closely with each other and with macrophage counts. In cell culture, exogenous anti-IL-1beta antibody led to a 40% maximum inhibition (approximately) of IL-8 production by lipopolysaccharide stimulated lung inflammatory cells. Comparable amounts of exogenous anti-TNFalpha antibodies achieved a 15% maximum inhibition (approximately) of IL-8 production. Anti-IL-1beta and anti-TNFalpha antibodies in combination did not inhibit IL-8 production beyond that achieved by anti-IL-1beta antibody alone. These results, in preterm newborns, support the concept of lung inflammation mediated in part by a macrophage, IL-1beta, and IL-8 cell cytokine pathway. The results also suggest that factors other than IL-1beta and TNFalpha regulate IL-8 expression in the lungs of preterm infants.

Renal tolerance with the use of intralipid-amphotericin B in low-birth-weight neonates.

Amphotericin B is still the first-line therapy for neonatal fungal infections. With several comparative trials of intralipid-based amphotericin B (IL-AmB) demonstrating its clinical effectiveness and reduced renal toxicity in adults, we examined the renal tolerance and infection outcome in low-birth-weight infants in our 48-bed NICU treated with IL-AmB. Over 2 years, 52 patients (58 courses) received > or = 10 days of IL-AmB. Nineteen charts (23 episodes) were randomly accessed and reviewed. Mean birthweight = 747 grams, gestational age = 25.6 weeks, total IL-AmB dosage = 19.8 +/- 3.3 mg/kg (n = 23); 20 of these episodes were fungal culture positive (9 fungemias). Only one patient (who died during therapy) had a rise in creatinine of > 0.3 mg/dL. Overall, serum creatinine decreased significantly after Day 10 of IL-AmB therapy, from 0.93 +/- 0.42 mg/dL at baseline, to 0.54 +/- 0.24 after 19 days of therapy (p < 0.0001). Serial urine output, serum potassium and potassium supplementation data showed no significant differences from baseline. No interruption of therapy nor infusion reactions occurred. Only one death occurred attributable to fungal infection. Intralipid-amphotericin B may provide an effective alternative in the antifungal therapy of low birthweight neonates, without nephrotoxicity. Further prospective, comparative trials are warranted.

Randomized, multicenter trial of inhaled nitric oxide and high-frequency oscillatory ventilation in severe, persistent pulmonary hypertension of the newborn.

BACKGROUND: Although inhaled nitric oxide (iNO) causes selective pulmonary vasodilation and improves oxygenation in newborn infants with persistent pulmonary hypertension, its effects are variable. We hypothesized (1) that the response to iNO therapy is dependent on the primary disease associated with persistent pulmonary hypertension of the newborn (PPHN) and (2) that the combination of high-frequency oscillatory ventilation (HFOV) with iNO would be efficacious in patients for whom either therapy alone had failed. METHODS: To determine the relative roles of iNO and HFOV in the treatment of severe PPHN, we enrolled 205 neonates in a randomized, multicenter clinical trial. Patients were stratified by predominant disease category: respiratory distress syndrome (n = 70), meconium aspiration syndrome (n = 58), idiopathic PPHN or pulmonary hypoplasia (excluding congenital diaphragmatic hernia) ("other": n = 43), and congenital diaphragmatic hernia (n = 34); they were then randomly assigned to treatment with iNO and conventional ventilation or to HFOV without iNO. Treatment failure (partial pressure of arterial oxygen [PaO2] < 60 mm Hg) resulted in crossover to the alternative treatment; treatment failure after crossover led to combination treatment with HFOV plus iNO. Treatment response with the assigned therapy was defined as sustained PaO2 of 60 mm Hg or greater. RESULTS: Baseline oxygenation index and PaO2 were 48 +/- 2 and 41 +/- 1 mm Hg, respectively, during treatment with conventional ventilation. Ninety-eight patients were randomly assigned to initial treatment with HFOV, and 107 patients to iNO. Fifty-three patients (26%) recovered with the initially assigned therapy without crossover (30 with iNO [28%] and 23 with HFOV [23%]; p = 0.33). Within this group, survival was 100% and there were no differences in days of mechanical ventilation, air leak, or supplemental oxygen requirement at 28 days. Of patients whose initial treatment failed, crossover treatment with the alternate therapy was successful in 21% and 14% for iNO and HFOV, respectively (p = not significant). Of 125 patients in whom both treatment strategies failed, 32% responded to combination treatment with HFOV plus iNO. Overall, 123 patients (60%) responded to either treatment alone or combination therapy. By disease category, response rates for HFOV plus iNO in the group with respiratory syndrome and the group with meconium aspiration syndrome were better than for HFOV alone or iNO with conventional ventilation (p < 0.05). Marked differences in outcomes were noted among centers (percent death or treatment with extracorporeal membrane oxygenation = 29% to 75%). CONCLUSIONS: We conclude that treatment with HFOV plus iNO is often more successful than treatment with HFOV or iNO alone in severe PPHN. Differences in responses are partly related to the specific disease associated with PPHN.

Partial liquid ventilation with perflubron in premature infants with severe respiratory distress syndrome. The LiquiVent Study Group.

BACKGROUND: The intratracheal administration of a perfluorocarbon liquid during continuous positive-pressure ventilation (partial liquid ventilation) improves lung function in animals with surfactant deficiency. Whether partial liquid ventilation is effective in the treatment of infants with severe respiratory distress syndrome is not known. METHODS: We studied the efficacy of partial liquid ventilation with perflubron in 13 premature infants with severe respiratory distress syndrome in whom conventional treatment, including surfactant therapy, had failed. Partial liquid ventilation was initiated by instilling perflubron during conventional mechanical ventilation to a volume approximating the functional residual capacity. Infants were considered to have completed the study if they received partial liquid ventilation for at least 24 hours. RESULTS: Ten infants received partial liquid ventilation for 24 to 76 hours. In the other three infants, partial liquid ventilation was discontinued within four hours in favor of high-frequency ventilation, which was not permitted by the protocol, and the data from these infants were excluded from the analysis. Within one hour after the instillation of perflubron, the arterial oxygen tension increased by 138 percent and the dynamic compliance increased by 61 percent; the mean (+/- SD) oxygenation index was reduced from 49 +/- 60 to 17 +/- 16. Chest radiographs showed symmetric filling, with patchy clearing during the return from partial liquid to gas ventilation. There were no adverse events clearly attributable to partial liquid ventilation. Infants were weaned from partial liquid to gas ventilation without complications. Eight infants survived to 36 weeks' corrected gestational age. CONCLUSIONS: Partial liquid ventilation leads to clinical improvement and survival in some infants with severe respiratory distress syndrome who are not predicted to survive.

Undetectable interleukin (IL)-10 and persistent IL-8 expression early in hyaline membrane disease: a possible developmental basis for the predisposition to chronic lung inflammation in preterm newborns.

We are interested in determining whether premature birth alters expression of counterregulatory cytokines which modulate lung inflammation. Production of proinflammatory cytokines tumor necrosis factor alpha. IL-1 beta, and IL-8 is regulated in part by the antiinflammatory cytokine IL-10. For preterm newborns with hyaline membrane disease, deficiencies in the ability of lung macrophages to express antiinflammatory cytokines may predispose to chronic lung inflammation. We compared the expression of pro- and antiinflammatory cytokines at the mRNA and protein level in the lungs of preterm and term newborns with acute respiratory failure from hyaline membrane disease or meconium aspiration syndrome. Four sequential bronchoalveolar lavage (BAL) samples were obtained during the first 96 h of life from all patients. All patients rapidly developed an influx of neutrophils and macrophages. Over time, cell populations in both groups became relatively enriched with macrophages. The expression of proinflammatory cytokine mRNA and/or protein was present in all samples from both patient groups. In contrast, IL-10 mRNA was undetectable in most of the cell samples from preterm infants and present in the majority of cell samples from term infants. IL-10 concentrations were undetectable in lavage fluid from preterm infants with higher levels in a few of the BAL samples from term infants. These studies demonstrate that 1) IL-10 mRNA and protein expression by lung inflammatory cells is related to gestational age and 2) during the first 96 h of life neutrophil cell counts and IL-8 expression decrease in BAL from term infants, but remain unchanged in BAL samples from preterm infants.

TTF-1 regulates lung epithelial morphogenesis.

TTF-1 is a homeodomain transcriptional factor expressed in thyroid, lung, and parts of the brain. In vitro, TTF-1 can activate the promoter of thyroid- and pulmonary-specific genes. We postulated that TTF-1 not only is essential for the activation of tissue-specific genes, but also may directly participate in epithelial cell morphogenesis. To test this postulate, we used an antisense oligonucleotide inhibitory strategy in an in vitro model of embryonic mouse lung branching morphogenesis. This strategy suppressed TTF-1 translation and inhibited lung branching morphogenesis. The resulting abnormal phenotype was characterized by hyperplastic and unorganized proliferation of epithelial cells in the airways. The mesenchymal compartment of the lung appeared to be unaffected. These results demonstrate, for the first time, that the expression of a homeoprotein transcriptional regulator is necessary for lung epithelial morphogenesis.

Comparison of dynamic and passive measurements of respiratory mechanics in ventilated newborn infants.

Pulmonary mechanics may differ in intubated and ventilated infants depending on whether they are measured by a dynamic or passive method. The objective of this study was to compare respiratory mechanics measured by a dynamic technique with those obtained by a single-breath occlusion technique in ventilated newborn infants. Thirty-one preterm and 15 term infants (mean +/- SD: gestational age, 29.3 +/- 2.3 and 39.5 +/- 1.4 weeks; birth weight, 1.2 +/- 0.5 and 3.4 +/- 0.4 kg; postnatal age, 12 +/- 13 and 5 +/- 4 days, respectively) were studied. Flows were measured through a pneumotachometer placed between the endotracheal tube and the ventilator circuit: tidal volume by integration of flow, and airway pressure directly with a pressure transducer. Airway occlusion was performed with a Neonatal Occlusion Valve (Bicore pulmonary monitor) at the end of inspiration, and the following relaxed exhalation was analyzed to give passive respiratory system compliance (Crs) and resistance (Rrs). These values were compared with dynamic respiratory system compliance (Cdyn) and dynamic expiratory resistance (Re) obtained with the PEDS system (P) within 1 hour, without an esophageal balloon and on the same ventilator settings. Dynamic respiratory system compliance and resistance measured with the PEDS and the Bicore systems did not differ significantly and were well correlated. Mean Cdyn (P) values in preterm and term infants were 77% and 77% of Crs; the equation of the regression line was Cdyn = 0.75 Crs + 0.02 and Cdyn = 0.78 Crs - 0.02; and standard error of the estimate (SEE) was 0.2 and 0.3 mL/cmH2O with a correlation coefficient (r) of 0.89 and 0.89 (P < 0.0001), respectively. The mean Re(P) values in preterm and term infants were 68% and 64% of Rrs, and the equation of the regression line was Re = 0.3 Rrs + 63 and Re = 0.5 Rrs + 20, with SEE of 25 and 20 cmH2O/L/sec, and r of 0.65 and 0.69 (P < 0.0001, P < 0.005), respectively. The two methods are non-invasive and were well tolerated. We conclude that passive and dynamic respiratory compliance and resistance measured in intubated infants are highly correlated, although the values measured by the passive technique are higher than those obtained by the dynamic technique.

Decreased alveolarization in baboon survivors with bronchopulmonary dysplasia.

In this study, 12 male baboons were delivered by hysterotomy at 75% of gestation. The development of a nonlethal baboon model permitted a study of lung growth and development in long-term survivors. Control animals were ventilated with clinically appropriate oxygen for the 21 d study period. BPD animals were ventilated with PPV and an FIO2 of 1.0 for 7 d, followed by an FIO2 of 0.8 for 14 d. They survived for 33 wk, at which time a right lower lobe lobectomy was performed. Controls showed normal well-alveolated lungs, whereas BPD lungs showed enlarged airspaces focally, nonclassifiable as alveoli, alveolar ducts, or respiratory bronchioles. Volume densities of alveoli were decreased significantly (p = 0.0009), and enlarged airspaces were significantly increased (p = 0.0003) in the BPD group compared with controls. Alveolar counts verified a significant decrease in alveoli (p = 0.004), and the internal surface area was significantly decreased (p = 0.05) in BPD treated animals compared with controls. These data document that a mild to moderate BPD lesion results in a significant and permanent loss of alveoli and a significant increase in enlarged, unclassifiable airspaces, which together result in a decreased total internal surface area in baboons that survive with their disease.