Non-invasive ventilation of the preterm infant

Aerosol Delivery of Lung Surfactant and Nasal CPAP in the Treatment of Neonatal Respiratory Distress Syndrome

After shifting away from invasive mechanical ventilation and intratracheal instillation of surfactant toward non-invasive ventilation with nasal CPAP and less invasive surfactant administration in order to prevent bronchopulmonary dysplasia in preterm infants with respiratory distress syndrome, fully non-invasive surfactant nebulization is the next Holy Grail in neonatology. Here we review the characteristics of animal-derived (clinical) and new advanced synthetic lung surfactants and improvements in nebulization technology required to secure optimal lung deposition and effectivity of non-invasive lung surfactant administration. Studies in surfactant-deficient animals and preterm infants have demonstrated the safety and potential of non-invasive surfactant administration, but also provide new directions for the development of synthetic lung surfactant destined for aerosol delivery, implementation of breath-actuated nebulization and optimization of nasal CPAP, nebulizer circuit and nasal interface. Surfactant nebulization may offer a truly non-invasive option for surfactant delivery to preterm infants in the near future.

Management of abdominal distension in the preterm infant with noninvasive ventilation: Comparison of cenit versus 2x1 technique for the utilization of feeding tube

BACKGROUND

Preterm infants are fed by orogastric / nasogastric tube until they reach maturation and coordination of sucking, swallowing and respiration at approximately 32-34 weeks of corrected age. While being on non-invasive ventilation (NIV), they frequently present abdominal distension. Currently at our institution two techniques are used for the management of abdominal distension in preterm infants fed by bolus via orogastric tube: cenit and 2 x 1.The aim of this study was to compare the proportion of preterm infants presenting NIV-associated abdominal distension with each of these techniques.

STUDY DESIGN

We conducted a randomized clinical trial including infants of <  36.6 weeks of gestation and <  1500 g of birth weight who were admitted to our NICU during the period of April 1, 2016 to April 1, 2018 and received NIV. The presence of abdominal distension >  2 cm was the primary outcome. Secondary outcomes were presence of reflux, regurgitation, oxygen saturation during feeding and days to reach full feedings. Feeding tube drainage, stool characteristics and the use of prokinetics were confounding variables.

RESULTS

A total of 97 patients were included. Forty-six in the cenit group and 51 in the 2 x 1 group. There was no difference in the proportion of infants with abdominal distension >  2 cm between groups. Oxygen saturation during feeding at volume of 150 ml/kg/day was higher in the cenit group with statistical significance.

CONCLUSION

The use of cenit or 2 x 1 technique in preterm infants with NIV did not improve abdominal distension or other indicators of feeding tolerance.

Randomized trial of mask or prongs for nasal intermittent mandatory ventilation in term infants with transient tachypnea of the newborn

BACKGROUND

The aim of this study was to compare nasal masks (NM) with binasal prongs (NP) for applying nasal intermittent mandatory ventilation (NIMV) by assessing the duration of respiratory distress, rate of intubation, and nasal trauma in term infants with transient tachypnea of the newborn (TTN).

METHODS

Infants with a gestational age ≥37 weeks and birthweight ≥2,000 g who had NIMV administered for TTN were enrolled. We randomly allocated 80 neonates to the NM (n = 40) or NP (n = 40) group. Duration of respiratory distress was the primary outcome of this study.

RESULTS

There were no statistically significant differences between the groups for the duration of tachypnea and NIMV (P = 0.94 and P = 0.13, respectively). No significant differences were observed between the two groups in terms of duration of oxygen supplementation and length of hospitalization (P = 0.72 and P = 0.70, respectively). The incidence of any grade of trauma and moderate trauma (grade II) was significantly higher in the NP group than in the NM group (P = 0.004 and P = 0.04, respectively). The rate of NIMV failure and other complications, including pneumothorax, pneumonia and feeding intolerance, was not significantly different in the groups.

CONCLUSIONS

In term infants with TTN, delivering NIMV using NP in comparison to using NM appears to be similar with regard to the duration of respiratory distress and preventing intubation. However, the use of NP involves a greater risk of trauma than that of NM.

Prolonged respiratory support of any type impacts outcomes of extremely low birth weight infants

OBJECTIVES

This study tested the hypothesis that longer duration of any type of respiratory support is associated with an increased rate of death or neurodevelopmental impairment (NDI) at 18-22 months.

METHODS

Retrospective cohort study using the Generic Database of NICHD Neonatal Research Network from 2006 to 2010. Infants were born at <27 weeks gestational age with birth weights of 401-1000 g. Respiratory support received during initial hospitalization from birth was characterized as follows: no support, only invasive support, only non-invasive support or mixed invasive, and non-invasive support. The primary outcome was death after 24 h of life or NDI at 18-22 months corrected age.

RESULTS

In a cohort of 3651 infants, 1494 (40.9%) died or had NDI. Cumulative respiratory support of any type beyond 60 days was associated with the likelihood of death or NDI. Infants who only received invasive support had the highest rate (89.1%), followed by those received mixed support (26.1%). Infants who received only non-invasive support had the lowest rate (7.7%). When compared to the only non-invasive support group, both invasive [OR 62.7 (95%CI 25.7, 152.6)] and mixed [OR 6.1 (95%CI 2.6, 14.4)] support groups were significantly more likely to die or have NDI.

CONCLUSION

Prolonged respiratory support, whether invasive or non-invasive, is associated with increased odds of a poor outcome. The proportion of infants with a poor outcome increased in a dose dependent manner by two factors: the cumulative duration of respiratory support beyond 60 days, and the extent to which invasive support is provided.

Evaluation of the maternal and fetal risk factors associated with neonatal care unit hospitalization time

OBJECTIVE

To evaluate maternal and neonatal risk factors associated with the length of hospital stay in the neonatal intensive care unit (NICU).

MATERIAL AND METHOD

This retrospective observational study was based on 3607 newborns who were admitted to the NICU of a tertiary teaching hospital from January 2012 through December 2014. Known obstetric risk factors associated with duration of hospitalization in NICUs were assessed including intrauterine growth restriction, maternal diabetes, oligohydramnios, chorioamnionitis, premeture rupture of membranes, preeclampsia, congenital malformations, neonatal sepsis, premature retinopathy, intracranial bleeding, necrotizing enterocolitis, meconium aspiration, maternal hypertension, fetal congenital cardiac malformations, congenital metabolic diseases, congenital hypothyroidism, pneumonia, pulmonary hypertension, bronchopulmonary dysplasia, pneumothorax and respiratory distress syndrome.

RESULTS

Gestational age (beta coefficient: -0.244, p<0.001) and birth weight (beta coefficient: -0.237, p<0.001) were significant confounders for duration of hospitalization in newborns.

CONCLUSION

Gestational age and the birth weight were the most important confounders for duration of hospitalization. Neonate care in developing countries would further benefit from additional large population-based long-term studies with broad parameters.

Noninvasive Ventilation for Preterm Twin Neonates with Respiratory Distress Syndrome: A Randomized Controlled Trial

Noninvasive ventilation has been proven to be effective strategies for reducing the need for endotracheal ventilation in preterm infant with respiratory distress syndrome (RDS), however the best option needs to be further determined. A single center, paired design, randomized, controlled trial was conducted between Jan 2011 and July 2014. Preterm twins with RDS were included. One of a pair was randomized to NIPPV, while another to NCPAP. Surfactant was administrated as rescue treatment. The primary outcome was the need for endotracheal ventilation. The secondary outcomes were the complications. 143 pairs were randomized and 129 pairs finished the trial. The rates of endotracheal ventilation did not differ significantly between NIPPV and NCPAP groups (11.9% vs 19.6%, P = 0.080). This difference was not observed in the subgroup of infants who received surfactant therapy (11.1% vs 19.7%, P = 0.087). No secondary outcomes also differed significantly between the two groups. NIPPV did not result in a significantly lower incidence of intubation as compared with NCPAP in preterm twins with RDS.

Comparison of non-synchronized nasal intermittent positive pressure ventilation versus nasal continuous positive airway pressure as post-extubation respiratory support in preterm infants with respiratory distress syndrome: a randomized controlled trial

OBJECTIVE

To determine whether post-extubation respiratory support via nsNIPPV decreases the need for mechanical ventilation (MV) compared to nasal continuous positive airway pressure (NCPAP) in preterm infants with respiratory distress syndrome (RDS).

METHODS

In this randomized, controlled, open, prospective, single-center clinical trial, we randomly assigned preterm ventilated infants with RDS to either nsNIPPV or NCPAP after extubation. The primary outcome, extubation failure, was defined by pre-specified failure criteria in the 72 hours after extubation.

RESULTS

A total of 63 preterm ventilated infants were randomized to receive either nsNIPPV (n = 31) or NCPAP (n = 32). Extubation failure occurred in six (19.3%) of nsNIPPV group compared with nine (28.12%) of NCPAP group and was statistically not significant (p = 0.55). The duration of NIV was significantly lower in nsNIPPV group as compared to NCPAP group (40.4 ± 39.3 hours versus 111.8 ± 116.4 hours, p = 0.003). The duration of supplementary oxygen was significantly lower in nsNIPPV versus NCPAP group (84.9 ± 92.1 hours versus 190.1 ± 140.5 hours, p = 0.002). The rates of BPD in nsNIPPV group (2/29, 6.9%) were significantly lower than in NCPAP group (9/28, 32.14%) (p = 0.02).

CONCLUSIONS

Compared to NCPAP, nsNIPPV appears to be a feasible mode of extubation in preterm infants with significant beneficial effects of reduced duration of NIV support, supplementary oxygen and decreased rates of BPD.

Noninvasive ventilation strategies for early treatment of RDS in preterm infants: an RCT

BACKGROUND AND OBJECTIVES

There is evidence that new methods of noninvasive ventilation (NIV) support have significantly changed respiratory distress syndrome (RDS) management in preterm infants. Further perspectives for neonatologists involve the assessment of different NIV strategies in terms of availability, effectiveness, and failure. This study evaluates the efficacy of 2 different NIV strategies for RDS treatment in very low birth weight (VLBW) infants: nasal synchronized intermittent positive pressure ventilation (NSIPPV), which is a modality of conventional ventilation with intermittent peak inspiratory pressure, and bilevel continuous positive airway pressure (BiPAP), not synchronized, with 2 alternate levels of continuous positive airway pressure.

METHODS

We conducted a 2-center randomized control study in 124 VLBW infants (<1500 g and <32 weeks of gestational age) with RDS who received NIV support (NSIPPV, n = 62; BiPAP, n = 62) within 2 hours of birth. We evaluated the performance of NIV strategies by selected primary outcomes (failure rate and duration of ventilation) and secondary outcomes.

RESULTS

The number of failures and duration of ventilation support did not differ between NSIPPV and BiPAP strategies (P > .05 for both). Moreover, no differences between groups were found regarding secondary outcomes (P > .05 for all).

CONCLUSIONS

The present data show no statistically significant differences between NSIPPV and BiPAP strategies in terms of duration of ventilation and failures, suggesting that both NIV techniques are effective in the early treatment of RDS in VLBW infants. Further randomized investigations on wider populations are needed to evaluate the effect of NIV techniques on long-term outcomes.

A prospective, randomized, controlled study of NIPPV versus nCPAP in preterm and term infants with respiratory distress syndrome

OBJECTIVE

To evaluate whether nasal intermittent positive pressure ventilation (NIPPV) compared with nasal continuous positive airway pressure (nCPAP) decreases the requirement for endotracheal ventilation in preterm and term infants with respiratory distress syndrome (RDS).

METHODS

This was a single center, randomized, controlled trial. A total of 179 preterm and term infants with RDS were randomized to NIPPV (n = 88) or nCPAP (n = 91). The clinical data of enrolled infants including blood gas analysis, PaO2 /FiO2 ratio, incidence of intubation, and complications, if occurred, were recorded. The primary outcome was the need for endotracheal ventilation. The secondary outcome was the measurement of favorable outcome, which was defined as discharged without any respiratory support and feeding well and gaining weight. Analysis followed slightly modified intention to treat principle.

RESULTS

Significantly less number of infants randomized to NIPPV group required intubation and mechanical ventilation compared with nCPAP group (11.4% vs. 20.9%, P < 0.05). A favorable outcome was more likely in infants randomized to NIPPV (93.2% vs. 84.6%, P < 0.05). In subgroup analysis, NIPPV was associated with reduced need for intubation in preterm (9.9% vs. 19.2%) and term (17.6% vs. 27.8%) infants, but the difference was statistically significant only in preterm infants(P < 0.05).

CONCLUSION

Treatment with NIPPV compared with nCPAP decreased the need for endotracheal ventilation and increased favorable outcome in preterm and term infants with RDS.

An integrative review of skin breakdown in the preterm infant associated with nasal continuous positive airway pressure

OBJECTIVE

To identify factors associated with skin injury during nasal continuous positive airway pressure (NCPAP) and describe differences in frequency, severity, and type of skin injuries when comparing nasal interfaces used during NCPAP in the preterm infant.

DATA SOURCES

Scientific databases were searched using provided key terms and yielded 113 articles.

STUDY SELECTION

Forty-six articles were included in this integrative review: six case studies, 22 with identified aim of examining skin and nasal injury during NCPAP; 18 included skin care considerations during NCPAP.

DATA EXTRACTION

Studies were categorized into four themes: types of nasal injuries; associated risk factors that increase incidence of injury; differences between NCPAP devices and/or nasal interface and corresponding rate and severity of nasal injury; and recommended prevention strategies to reduce iatrogenic cutaneous injury.

DATA SYNTHESIS

Skin injury was a common theme during neonatal NCPAP with skin breakdown rates of 20% to 60%. Increased skin injury risk was associated with smaller infant size, gestational age, and duration of therapy. Nursing care strategies to improve skin integrity during NCPAP had little supportive evidence. Nursing practice is varied with reportedly little standardized care during NCPAP therapy. Recommendations for specific care strategies to reduce skin injury during NCPAP were supported by limited experimental studies.

CONCLUSIONS

Risk factors during NCPAP include nasal injury and trauma secondary to tight-fitting nasal interfaces necessary to provide continuous distending pressure for respiratory stability. Identifying strategies to reduce skin breakdown will support noninvasive treatment success, reduce reintubation rates, reduce sepsis, reduce patient discomfort, and improve developmental outcomes during NCPAP use.

Facial skin breakdown in patients with non-invasive ventilation devices: report of two cases and indications for treatment and prevention

Non-invasive ventilation (NIV) provides an effective ventilatory support in patients with respiratory failure without endotracheal intubation. However, there are potential problems with its clinical application and the development of pressure ulcers represents a common complication. Often several intensive care units treat facial skin breakdown related to NIV. In this article, we report our experience in treatment and prevention of these lesions, emphasising the higher risk of certain age groups to develop them, such as preterm infants and elderly patients with comorbidities. We performed daily disinfection of the lesions followed by application of topical cream containing hyaluronic acid (HA) sodium salt. In addition, in order to prevent worsening of injury, we applied a cushion made of gauze pad containing HA sodium salt between the skin and the masks, so as to reduce friction between the NIV devices and the skin. Local medical treatment allowed complete reepithelialisation of the injured skin areas. Systematic monitoring of patients' faces is essential to detect early damages and to intervene with appropriate therapy, especially in preterm infants and elderly. Moreover, refining the devices with the proposed protective cushion can reduce pressure ulcers and increase comfort for the patients.

N-SIPPV versus bi-level N-CPAP for early treatment of respiratory distress syndrome in preterm infants

OBJECTIVE

Non-invasive ventilation (NIV) for RDS in extremely/very low birth-weight infants represents the new challenge for neonatologists. In this regard, data comparing the effectiveness of Bi-Level-NCPAP (BiPAP) versus nasal synchronized intermittent positive pressure ventilation (NSIPPV) as primary mode of treatment for RDS are lacking.

STUDY DESIGN

We conducted a retrospective study from December 2007 to December 2010 in seventy-eight infants, who received NIV (N-SIPPV: 33; BiPAP: 45). The primary outcomes were the length and failure of NIV. Secondary outcomes were adverse short-long term pulmonary outcomes, multiple doses of surfactant and others.

RESULTS

There were no significant differences (p > 0.05) between the two different NIV modes.

CONCLUSION

The present findings suggest that N-SIPPV and BiPAP gives similar results in the RDS treatment. We did not find a benefit of one over the other ventilation mode and both could be constitute a valid option to conventional mechanical ventilation. The theoretical benefits of these two different methods of NIV are tidal volume enhancement, improvements of the functional residual capacity and of the mean airway pressure and reducing apnea episodes. Further randomized studies to assess the advantages and the efficacy of different methods of NIV for the treatment of the RDS are needed.

Late administration of surfactant replacement therapy increases surfactant protein-B content: a randomized pilot study

BACKGROUND

Surfactant dysfunction may contribute to the development of bronchopulmonary dysplasia (BPD) in persistently ventilated preterm infants. We conducted a multicenter randomized, blinded, pilot study to assess the safety and efficacy of late administration of doses of a surfactant protein-B (SP-B)-containing surfactant (calfactant) in combination with prolonged inhaled nitric oxide (iNO) in infants ≤1,000 g birth weight (BW).

METHODS

We randomized 85 preterm infants ventilated at 7-14 d after birth to receive either late administration of surfactant (up to 5 doses) plus prolonged iNO or iNO alone. Large aggregate surfactant was isolated from daily tracheal aspirates (TAs) for measurement of SP-B content, total protein, and phospholipid (PL).

RESULTS

Late administration of surfactant had minimal acute adverse effects. Clinical status as well as surfactant recovery and SP-B content in tracheal aspirate were transiently improved as compared to the controls; these effects waned after 1 d. The change in SP-B content with surfactant dosing was positively correlated with SP-B levels during treatment (r = 0.50, P = 0.02).

CONCLUSION

Low SP-B values increased with calfactant administration, but the relationship of this response to SP-B levels suggests that degradation is a contributing mechanism for SP-B deficiency and surfactant dysfunction. We conclude that late therapy with surfactant in combination with iNO is safe and transiently increases surfactant SP-B content, possibly leading to improved short- and long-term respiratory outcomes.

Nasal intermittent positive pressure ventilation versus nasal continuous positive airway pressure in neonates: a systematic review and meta-analysis

OBJECTIVE

To compare the efficacy and safety of Nasal intermittent positive pressure ventilation (NIPPV) and Nasal continuous positive airway pressure (nCPAP) in neonates.

METHODS

Standard search strategy for the Cochrane Neonatal Review Group was performed. The participants were both preterm and term infants suffering from neonatal respiratory distress syndrome or experiencing apnea of prematurity.

RESULTS

14 eligible andomized controlled trials involving 1052 newborn infants were included. The study quality and evidence validity was defined as moderate. As compared with nCPAP, NIPPV significantly reduced the incidence of endotracheal ventilation OR 0.44, 95%CI 0.31 - 0.63, increased the successful rate of extubation (OR 0.15, 95%CI:0.08 - 0.31), and had a better outcome indicated by decreased death and/or bronchopulmonary dysplasia (OR 0.57, 95% CI:0.37 - 0.88). Moreover, NIPPV decreased the number of apneic episodes of prematurity (WMD-0.48, 95%CI 0.58 - 0.37), and marginally decreased the incidence of bronchopulmonary dysplasia (OR 0.63, 95%CI 0.39 - 1.00). No side effects specifically associated with NIPPV were reported.

CONCLUSION

NIPPV could be used to reduce endotracheal ventilation, increase successful extubation, decrease the rate of apnea of prematurity, and have better outcome indicated by fewer death and/or bronchopulmonary dysplasia in preterm and term newborn infants.

Effect of amplitude and inspiratory time in a bench model of non-invasive HFOV through nasal prongs

BACKGROUND AND OBJECTIVES

Non-invasive high frequency oscillatory ventilation through nasal prongs (nHFOV) has been proposed to combine the advantages of oscillatory pressure waveform and non-invasive interface. We studied the effect of oscillation amplitude and inspiratory time on the pressure transmission and tidal volume delivery through different nasal prongs.

METHODS

In vitro mechanical study on a previously described bench model of nHFOV. The model was built connecting SM3100A tubings to a neonatal lung model, via two differently sized binasal prongs. A circuit with no nasal prongs was used as control. Tidal volume (T(v) ), oscillatory pressure ratio (ΔP(dist) /ΔP(prox) ), and ventilation (DCO(2) ) were measured across a range of amplitudes and inspiratory times (I(T) ). Measurements were performed with a low-dead space hot wire anemometer coupled with a pressure transducer.

RESULTS

Using both nasal prongs, T(v) , ΔP(dist) /ΔP(prox) , and DCO(2) were 83%, 40%, and 71%, respectively, of those provided with the control circuit. No differences were noticed between small and large prongs. T(v) and ΔP(prox) were linked by a quadratic relationship. T(v) plateaus for amplitude values >65 cmH(2) O. ΔP(dist) /ΔP(prox) shows same tendency. Same results were obtained with both types of prongs and with increasing I(T) . On the whole, mean T(v) was higher with I(T) at 50% than at 33% (2.4 ml vs. 1.4 ml; P < 0.001).

CONCLUSIONS

Changing oscillation amplitude and I(T) has a significant effect on ventilation. Varying these two parameters provides a theoretical T(v) within the ideal values for HFOV also using the smallest nasal prongs.

Current methods of non-invasive ventilatory support for neonates

Non-invasive ventilatory support can reduce the adverse effects associated with intubation and mechanical ventilation, such as bronchopulmonary dysplasia, sepsis, and trauma to the upper airways. In the last 4 decades, nasal continuous positive airway pressure (CPAP) has been used to wean preterm infants off mechanical ventilation and, more recently, as a primary mode of respiratory support for preterm infants with respiratory insufficiency. Moreover, new methods of respiratory support have been developed, and the devices used to provide non-invasive ventilation (NIV) have improved technically. Use of NIV is increasing, and a variety of equipment is available in different clinical settings. There is evidence that NIV improves gas exchange and reduces extubation failure after mechanical ventilation in infants. However, more research is needed to identify the most suitable devices for particular conditions; the NIV settings that should be used; and whether to employ synchronized or non-synchronized NIV. Furthermore, the optimal treatment strategy and the best time for initiation of NIV remain to be identified. This article provides an overview of the use of non-invasive ventilation (NIV) in newborn infants, and the clinical applications of NIV.

Noninvasive ventilation for respiratory distress syndrome: a randomized controlled trial

CONTEXT

Strategies for reducing exposure to endotracheal ventilation through the use of early noninvasive ventilation has proven to be safe and effective, but the option with the greatest benefits needs to be determined.

OBJECTIVE

To determine, in infants with respiratory distress syndrome, if early nasal intermittent positive-pressure ventilation (NIPPV) compared with nasal continuous positive airway pressure (NCPAP) decreases the need for mechanical ventilation.

PATIENTS AND METHODS

In this single-center, randomized controlled trial, infants (gestational ages 26 to 33/7 weeks) with respiratory distress syndrome were randomly assigned to receive early NIPPV or NCPAP. Surfactant was administered as rescue therapy. The primary outcome was the need for mechanical ventilation within the first 72 hours of life.

RESULTS

A total of 200 infants, 100 in each arm, were randomly assigned. Rates of the primary outcome did not differ significantly between the NIPPV (25%) and NCPAP (34%) groups (relative risk [RR]: 0.71 [95% confidence interval (CI): 0.48–1.14]). In posthoc analysis, from 24 to 72 hours of life, significantly more infants in the NIPPV group remained extubated compared with those in the NCPAP groups (10 vs 22%; RR: 0.45 [95% CI: 0.22–0.91]). This difference was also noted in the group of infants who received surfactant therapy, NIPPV (10.9%), and NCPAP (27.1%) (RR: 0.40 [95% CI: 0.18–0.86]).

CONCLUSIONS

Early NIPPV did not decrease the need for mechanical ventilation compared with NCPAP, overall, in the first 72 hours of life. However, further studies to assess the potential benefits of noninvasive ventilation are warranted, especially for the most vulnerable or preterm infants.

Fatty acid-binding proteins and peribronchial angiogenesis in bronchopulmonary dysplasia

Inflammation plays a key role in the pathogenesis of bronchopulmonary dysplasia (BPD). Fatty acid-binding proteins (FABPs) 4 and 5 regulate the inflammatory activity of macrophages. Whether FABPs 4 and 5 could play a role in the pathogenesis of BPD via the promotion of macrophage inflammatory activity is unknown. This study sought to examine whether the expression levels of FABP4 and FABP5 were altered in bronchoalveolar lavage fluid and lung tissue in a baboon model of BPD. This study also sought to characterize the cell types that express these proteins. Real-time PCR, immunoblotting, immunohistochemistry, and double immunofluorescence were used to examine the expression of FABPs in samples of BPD. Morphometric analysis was used to quantify FABP4-positive peribronchial blood vessels in lung sections. FABP4 was primarily expressed in macrophages in samples of BPD. In addition, FABP4 was expressed in the endothelial cells of blood vessels in peribronchial areas and the vasa vasorum, but not in the alveolar vasculature in samples of BPD. FABP4 concentrations were significantly increased in lungs and bronchoalveolar lavage fluid samples with BPD. An increased density of FABP4-positive peribronchial blood vessels was evident in both baboon and human BPD sections. FABP5 was expressed in several cell types, including alveolar epithelial cells and macrophages. FABP5 concentrations did not show any significant alterations in BPD. In conclusion, FABP4 but not FABP5 levels are increased in BPD. FABP4 is differentially expressed in endothelial cells of the bronchial microvasculature, which demonstrates a previously unrecognized expansion in BPD.