From bench to bedside: in vitro and in vivo evaluation of a neonate-focused nebulized surfactant delivery strategy

Background

Non-invasive delivery of nebulized surfactant has been a neonatology long-pursued goal. Nevertheless, the clinical efficacy of nebulized surfactant remains inconclusive, in part, due to the great technical challenges of depositing nebulized drugs in the lungs of preterm infants. The aim of this study was to investigate the feasibility of delivering nebulized surfactant (poractant alfa) in vitro and in vivo with an adapted, neonate-tailored aerosol delivery strategy.

Methods

Particle size distribution of undiluted poractant alfa aerosols generated by a customized eFlow-Neos nebulizer system was determined by laser diffraction. The theoretical nebulized surfactant lung dose was estimated in vitro in a clinical setting replica including a neonatal continuous positive airway pressure (CPAP) circuit, a cast of the upper airways of a preterm neonate, and a breath simulator programmed with the tidal breathing pattern of an infant with mild respiratory distress syndrome (RDS). A dose-response study with nebulized surfactant covering the 100–600 mg/kg nominal dose-range was conducted in RDS-modelling, lung-lavaged spontaneously-breathing rabbits managed with nasal CPAP. The effects of nebulized poractant alfa on arterial gas exchange and lung mechanics were assessed. Exogenous alveolar disaturated-phosphatidylcholine (DSPC) in the lungs was measured as a proxy of surfactant deposition efficacy.

Results

Laser diffraction studies demonstrated suitable aerosol characteristics for inhalation (mass median diameter, MMD = 3 μm). The mean surfactant lung dose determined in vitro was 13.7% ± 4.0 of the 200 mg/kg nominal dose. Nebulized surfactant delivered to spontaneously-breathing rabbits during nasal CPAP significantly improved arterial oxygenation compared to animals receiving CPAP only. Particularly, the groups of animals treated with 200 mg/kg and 400 mg/kg of nebulized poractant alfa achieved an equivalent pulmonary response in terms of oxygenation and lung mechanics as the group of animals treated with instilled surfactant (200 mg/kg).

Conclusions

The customized eFlow-Neos vibrating-membrane nebulizer system efficiently generated respirable aerosols of undiluted poractant alfa. Nebulized surfactant delivered at doses of 200 mg/kg and 400 mg/kg elicited a pulmonary response equivalent to that observed after treatment with an intratracheal surfactant bolus of 200 mg/kg. This bench-characterized nebulized surfactant delivery strategy is now under evaluation in Phase II clinical trial (EUDRACT No.:2016–004547-36).

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1096-9) contains supplementary material, which is available to authorized users.

Surgical management of Necrotizing Enterocolitis in an Incredibly Low Birth Weight infant and review of the Literature

Survival of preterm infants have dramatically improved over the last decades. Nonetheless, infants born preterm remain vulnerable to many complications, including necrotizing enterocolitis (NEC). The severity of the disease and the mortality rate are directly correlated with decreasing gestational age and birth weight. Despite surgical treatment mortality rate remains very high in extremely premature infants, especially in newborns at the lowest limit of viability. Survival of infants of birth weight (BW) below 750 g has been increasingly reported in recent years, however the overall mortality in extremely low "BW" infants (ELBW) requiring surgery for NEC has not decreased over the past years. We describe our experience with a male preterm infant who survived after an ileostomy procedure for Bell stage II NEC, with improving neuromotor skills at 2 years follow up. Although standard indication to surgery is Bell stage III, in our case the choice of minimal laparotomy, exploration of the bowel and ileostomy at Bell stage II was safe and effective. Our experience suggest that surgery has not a negative impact on survival and ileostomy could prevent further damage of the bowel in NEC. We hypothesize that indication to surgery at an earlier stage may prevent further progression of the disease without a significantly negative impact on survival. Further studies are needed to confirm the appropriateness of this approach in ELBW infants.

Fibrinogen kinetics and protein turnover in obese non-diabetic males: effects of insulin

BACKGROUND

Although hyperfibrinogenemia and insulin resistance are common in obesity and diabetes mellitus, the impact of obesity per se on fibrinogen turnover and the insulin effects on fibrinogen and protein kinetics is unknown.

METHODS

We measured fibrinogen and albumin fractional (FSR) and absolute (ASR) synthesis rates, as well as protein turnover, in non-diabetic, obese and in control male subjects both before and following an euglycemic, euaminoacidemic, hyperinsulinemic clamp, using L-[(2)H(3)]-Leucine isotope infusion.

RESULTS

In the obese, basal fibrinogen concentrations was approximately 25% greater (p < 0.035), and fibrinogen pool approximately 45% greater (p < 0.005), than in controls. Both FSR and ASR of fibrinogen were similar to control values. With hyperinsulinemia, although fibrinogen FSR and ASR were not significantly modified with respect to baseline in either group, fibrinogen ASR resulted to be approximately 50% greater in the obese than in controls (p < 0.015). Hyperinsulinemia equally stimulated albumin synthesis and suppressed leucine appearance from endogenous proteolysis in both groups. Amino acid clearance was also similar. In the obese, the insulin-mediated glucose disposal was approximately 50% lower (p < 0.03) than in controls, and it was inversely correlated with fibrinogen ASR during the clamp in both groups (r = - 0.58).

CONCLUSIONS

In obese, non-diabetic males, post absorptive fibrinogen production is normal. Whole-body amino acid disposal, basal and insulin-responsive protein degradation, and albumin synthesis are also normal. However, the greater fibrinogen ASR in the obese with hyperinsulinemia, and the inverse relationship between insulin sensitivity and clamp fibrinogen production, suggest a role for hyperinsulinemia and/or insulin resistance on fibrinogen production in obesity.

[EuroNeoStat: a European information system on the outcomes of care for very-low-birth-weight infants (< 1500 g)]

BACKGROUND

Prematurity rates are increasing throughout the world. Despite an overall rather small percentage of very low birth weight infants (VLBWI), which is approx. 1-2 % in most countries, these infants contribute significantly to morbidity and neonatal and infant mortality rates.

METHODS

EuroNeoStat was initiated as an European information system on the outcomes of VLBWI to monitor and improve the care of these infants throughout Europe. EuroNeoStat includes an initiative, called EuroNeoSafe, to promote the safety of these high risk preterm infants. Perinatal and neonatal data from VLBWI is collected without using data that identify individuals or institutions. These data is analyzed at the coordination center in Bilbao. All institutions taking care on VLBWI in Europe can participate in this network and will be able to compare their own outcome data with other institutions from the network. Information on EuroNeoStat and the current data set is available on www.euroneostat.org.

CONCLUSION

Successful initiatives aiming at improving outcomes in perinatal and neonatal care require collaborative networking, an attitude of constructive criticism and thorough comparative analysis of the outcomes and incidents in the health-care process.

Fecal fat measurement in the presence of long- and medium-chain triglycerides and fatty acids. Comparison of three methods

BACKGROUND

It has been suggested that some of the limitations of the Van de Kamer method for fecal fat measurement could be overcome with the Jeejeebhoy method or the near-infrared reflectance assay.

METHODS

To test this hypothesis, a fecal fat test was carried out with the three methods, adding butter or MCT oil to the diet of four steatorrhoic patients. An in vitro recovery study of long- and medium-chain triglycerides was also performed.

RESULTS

The Jeejeebhoy method measured long- and medium-chain fats more accurately than the Van de Kamer method. It found consistently higher steatorrhea values. Mean results of the near-infrared reflectance analysis resembled those of the Van de Kamer method, but with wide discordance of individual data.

CONCLUSION

The Jeejeebhoy method is more accurate than the Van de Kamer method for fecal fat measurement. The difference may be clinically relevant when most fecal fatty acids derive from medium-chain triglycerides. Near-infrared reflectance may be a viable proposition only when a greater degree of approximation is acceptable.

[Transportation of the critical newborn infant and child]

Advance in the science and technology of neonatal and pediatric critical care have resulted in improved outcome for high risk newborn and children. Effective interhospital transport programmes are necessary for the appropriate use of resources and has become an integral component of regionalized perinatal care. It is now well established that use of an organized neonatal and pediatric transport team results in a fall in mortality and morbidity of infant. The American College of Obstetrician and Gynecologist and, recently, American Academy of Pediatrics published guidelines and recommendations for safe interhospital transfer of neonates, infants and children. Training of personnel, selection of equipment, organization and communication between hospitals are critical elements of a successful transport system. We present an overview of the role, principles and operating procedures of such neonatal-pediatric transport team and the basis of clinical stabilization before and during transfer. We also discuss data of the first 17 month experience of the Neonatal-Pediatric Transport Service of the Department of Pediatrics, University of Padua.

Medium-chain triglyceride absorption in patients with pancreatic insufficiency

BACKGROUND

The role of medium-chain triglycerides (MCTs) in the management of patients with pancreatic insufficiency is controversial. The aim of the study was to evaluate the absorption of MCTs in the presence of pancreatic insufficiency and the effect of pancreatic extracts on MCT absorption so as to clarify whether the replacement of usual dietary fats with MCTs is cost-effective.

METHODS

Six patients with severe pancreatic steatorrhea were for 5 days fed a low-fat diet to which butter (long-chain triglycerides (LCTs)) or MCT oil was added, with and without pancreatic extracts, in a crossover design.

RESULTS

Fecal weight and nitrogen losses were the same during MCT and LCT intake. Steatorrhea was substantial during both periods but was significantly lower during MCT than LCT intake. Fecal weight and nitrogen and fat losses were reduced by pancreatic extracts in both diets. Steatorrhea was the same when MCTs and LCTs were consumed together with pancreatic extracts.

CONCLUSIONS

MCTs are absorbed better than LCTs in the presence of pancreatic insufficiency but require pancreatic extracts for optimal absorption. No advantage is to be expected from replacing usual dietary fats with MCTs if pancreatic supplements are used.

Effect of high doses of human recombinant erythropoietin on the need for blood transfusions in preterm infants

To determine whether prophylactic treatment with recombinant human erythropoietin (rHuEPO) and iron would reduce the need for blood transfusions, we randomly assigned 22 premature infants with gestational ages less than or equal to 32 weeks and birth weights less than or equal to 1.75 kg to receive rHuEPO, 400 IU/kg three times a week, plus iron, 20 mg/wk intravenously, from the second day of life (11 infants), or no rHuEPO and no iron (11 infants). The two groups had similar birth weights and clinical variables. The treated infants required fewer blood transfusions (0.8 +/- 1.5 vs 3.1 +/- 2.1; p = 0.01) and less volume of packed erythrocytes (14.2 +/- 25.9 vs 48.4 +/- 34.0 ml/kg; p = 0.02). The amounts of blood sampled were not different (19.5 +/- 21.1 vs 27.8 +/- 19.1 ml/kg; p = 0.35). Reticulocyte and hematocrit values were higher in the treated group (4.46% +/- 0.8% vs 1.49% +/- 1.1% (p = 0.0001) and 48.1% +/- 7.3% vs 43.8% +/- 4.7% (p = 0.004), respectively). No side effects of either rHuEPO or intravenously administered iron were noted. These data indicate that rHuEPO, in combination with iron supplementation, is effective in reducing the need for blood transfusions in the premature infant. More information is needed on dosage, timing, and iron and vitamin supplementation.

Partition of energy metabolism in the surgical newborn

Variations in energy expenditure (EE) and substrate utilization were investigated in 12 surgical neonates (body weight, 2.81 +/- 0.15 kg) receiving total parenteral nutrition (TPN) at an energy intake of 66.34 +/- 2.16 kcal/kg/d in a thermoneutral environment of 32 degrees C to 34 degrees C. Respiratory gas exchange was continuously recorded for 12 hours by a computerized, open-circuit indirect calorimeter. Physical activity was monitored on a modified Freymond scale. Urine was collected over 3 days, including the time of the calorimetry study to determine the urinary nitrogen excretion rate. Oxygen consumption, carbon dioxide production, nonprotein respiratory quotient, and EE were calculated according to the principles of indirect calorimetry for each 30-minute period and for the entire 12 hours. During the indirect calorimetry study the patients were receiving a fat-free TPN mixture consisting of 10% glucose and 2% amino acids (GL/AA) for 8 hours. The fat-free TPN was interrupted by an isocaloric and isovolemic infusion of intralipid 10% (IL) for 4 hours. The effect of physical activity on EE was evaluated separately according to the macronutrient intake (GL/AA for 8 hours v IL for 4 hours) and then combined throughout the 12 hours of intravenous alimentation. The neonates were resting during 80% of the 12-hour study time (range, 38% to 90%). The partition of EE expressed as mean +/- SEM in kcal/kg/d was: total EE 48.5 +/- 2.1; resting EE 43.9 +/- 1.6; energy cost of activity 4.6 +/- 1.3.(ABSTRACT TRUNCATED AT 250 WORDS)

Resting energy expenditure is increased in infants and children with extrahepatic biliary atresia

To determine if liver dysfunction in children affects energy and macronutrient homeostasis, we performed 13 metabolic studies in 11 patients (age, 17.8 +/- 5.9 months [mean +/- SEM]) with extrahepatic biliary atresia (EHBA). Nutritional balance, indirect calorimetry, anthropometry, and biochemical liver function tests were utilised. Sixty-four percent of the energy losses were in the form of stool fat. Energy expenditure (68 kcal/kg/d) was 29% higher than normal (P less than 0.0025). Only one third of the metabolisable energy intake (37 kcal/kg/d) was stored in the body for new tissue synthesis. In spite of the bountiful protein intake for age, the increased protein oxidation (2g/kg/d) resulted in a virtually zero mean nitrogen balance. In addition, four patients oxidised endogenous protein as well. The respiratory quotient was 0.96, and did not change significantly between pre- and post-meal measurements, suggesting a predominant utilisation of carbohydrate for energy metabolism. Net lipid oxidation was severely diminished. We found that the higher the serum aspartate aminotransferase level (previously named SGOT), the lower the net fat oxidation, and the higher the conversion of glucose to fat. These data suggest that markedly increased energy expenditure contributes to the malnutrition of patients with EHBA. We characterised for the first time how severe liver disease in infants and children affects carbohydrate, fat, and protein metabolism, thus inducing protein-energy malnutrition.

Metabolism of intravenous fat emulsion in the surgical newborn

The metabolism of an intravenous (IV) fat emulsion was investigated by the combination of chemical balance and computerized indirect calorimetry techniques in 21 newborns (birth weight, 3.0 +/- 0.1 kg; mean +/- SE). All babies were appropriate for gestational age and received total parenteral nutrition after a major surgical procedure. The study was divided into two consecutive periods. Phase 1 consisted of infusion of 10% glucose and 2% amino acid solutions for 24 hours, and phase 2 involved the "Intralipid utilization test" (isocaloric and isovolemic infusion of Intralipid 10% for four hours). The caloric intake was 67.1 +/- 1.9 kcal/kg/d during both phases of the study. The resting energy expenditure was 44.8 +/- 1.6 and 46.5 +/- 1.8 kcal/kg/d during phases 1 and 2 respectively. During glucose/amino acid infusion, 12 patients oxidized endogenous fat, and de novo lipogenesis from glucose was observed in nine. During the Intralipid infusion, there was a significant and progressive decrease of carbon dioxide production, respiratory quotient, and carbohydrate utilization (oxidation plus conversion to fat). Net lipogenesis ended and fat utilization significantly increased. By the second hour of Intralipid infusion, 58% of energy expenditure was derived from fat oxidation. The drop in carbon dioxide production correlated positively with the decrease in carbohydrate utilization (r = .07; P less than .001). During the third and fourth hours of phase 2, the percentage of fat utilized was negatively correlated with the amount of fat given (r = -.07; P less than .01). The surgical neonate showed rapid metabolic adaptation to Intralipid infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics of protein sparing effect of total parenteral nutrition in the surgical infant

To determine the best formula to prevent protein depletion, 31 surgical infants on intravenous (IV) diet were studied. The study was divided into two phases. Phase I diet included 5% glucose and 1.5% or 2% amino acid infusion; phase II diet consisted of 5% glucose and 1.5% or 2% aminoacid plus 10% Intralipid. In each phase, oxygen consumption, carbon dioxide production, and energy expenditure were determined. The utilization of carbohydrate, fat, and protein was calculated from urinary nitrogen excretion and nonprotein respiratory quotient. The mean caloric intake during phase I and phase II was 62 and 94 kcal/kg/d, respectively. A positive nitrogen balance was obtained in infants receiving fat-free total parenteral nutrition (TPN) with a mean protein intake of 2.6 g/kg/d and a mean energy intake exceeding the energy expenditure by 24%. Infusion of more calories as Intralipid (phase II) caused a significant reduction in protein oxidation, thus protein contribution to the energy expenditure and an increase in protein retention. We conclude that supplementation of low-calorie TPN diets with Intralipid increases protein sparing and is preferable to the administration of very high glucose loads.

Carnitine and the premature

After birth, the main energy fuel for the newborn is constituted by fat. Carnitine is necessary for the beta-oxidation of long chain fatty acids at the mitochondrial level, and seems also to have a role in the metabolism of the branched-chain amino acids, in ammonia detoxification, and in urea production. Colostrum is particularly rich in carnitine whereas semi-elemental formulae and soy-based formulae contain little or no carnitine. Since the newborn has a low capacity for carnitine biosynthesis, it seems useful to administer L-carnitine to infants on total parenteral nutrition, soy-based or semi-elemental formulae.

The premature breech presentation: outcome of newborn infants born by vaginal or abdominal delivery

There is ample documentation that breech full-term infants delivered vaginally have a higher perinatal morbidity and mortality rate than breech infants born via cesarean section. Until now, little emphasis has been placed on the risks to premature newborns born in breech presentation. Therefore, the authors have considered all singleton pregnancies with infants in breech presentation admitted to the Department of Obstetrics, University of Padova, from January 1978 to December 1979 and delivered before 36-weeks gestation. On the basis of obstetric management, the authors have obtained two groups: Group A comprised 36 infants born by vaginal delivery; Group B totaled 32 newborns delivered by cesarean section. Mean gestational age and birthweight were comparable. Of the neonatal events considered, the following were significantly different: Apgar score at 5 minutes less than 7 (A = 30.6%; B = 9.3%), mortality (A = 13.8%; B = 0), neurologic sequelae in the infants discharged from the neonatal intensive care unit (NICU) (A = 50%; B = 9.1%) and the sum of mortality and long term sequelae (A = 22.2%; B = 3.1%). The authors conclude that cesarean section performed in mothers with impending preterm breech delivery decreases the neonatal mortality rate and improves the long-term outcome.

Congenital choanal atresia: the postoperative care

A case of congenital bilateral bony choanal atresia treated by surgery is reported. A new method of insertion and retention of the modelling tubes to prevent stenosis is described. This method has the following advantages: 1. it provides a good insertion and retention of the modelling tubes; 2. it doesn't provoke any trauma of the nasal septum, soft palate and nostril; 3. the insertion of the tubes doesn't require general anesthesia; 4. it's well tolerated.