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Pasteka R, Hufnagl L, Forjan M, Berger A, Werther T, Wagner M. Positive end-expiratory pressure and surfactant administration mode influence function in ex-vivo premature sheep lungs. Acta Paediatr 2024; 113:722-730. [PMID: 38149457 DOI: 10.1111/apa.17083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 12/12/2023] [Accepted: 12/18/2023] [Indexed: 12/28/2023]
Abstract
AIM Respiratory distress syndrome often necessitates endotracheal surfactant administration in extremely preterm infants. Our study aimed to explore a multi-modal simulation tool for investigating treatment strategies in ex vivo sheep lungs during spontaneous breathing. METHODS An electromechanical lung simulator (xPULM) mimicking spontaneous breathing was coupled with a non-aerated premature sheep lung, replicating a premature respiratory system. Changes in tidal volume for different positive end-expiratory pressure (PEEP) levels prior to and after either bolus or nebulised surfactant administration were compared. RESULTS In two preterm sheep lungs, we observed a progressive decline in tidal volume with increasing PEEP levels prior to surfactant delivery from 0.30 ± 0.01 mL at zero PEEP to 0.04 ± 0.01 mL at 15 cmH2O PEEP. Our measurements showed that both bolus (p < 0.05) and nebulised (p < 0.05) surfactant administration resulted in a significant increase in tidal volume, with no significant difference (p = 0.71) between the two methods. CONCLUSION The experimental setup demonstrated the feasibility of xPULM for investigating the effectiveness of different PEEP levels and modes of surfactant administration with respect to tidal volume in premature sheep lungs. The lack of adequate lung water resorption in our model warrants further investigations.
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Affiliation(s)
- Richard Pasteka
- Department Life Science Engineering, Competence Centre Medical Engineering & Integrated Healthcare, University of Applied Sciences Technikum Wien, Vienna, Austria
| | - Lisa Hufnagl
- Department of Paediatrics and Adolescent Medicine, Comprehensive Centre for Paediatrics, Division of Neonatology, Paediatric Intensive Care and Neuropaediatrics, Medical University of Vienna, Vienna, Austria
| | - Mathias Forjan
- Department Life Science Engineering, Competence Centre Medical Engineering & Integrated Healthcare, University of Applied Sciences Technikum Wien, Vienna, Austria
| | - Angelika Berger
- Department of Paediatrics and Adolescent Medicine, Comprehensive Centre for Paediatrics, Division of Neonatology, Paediatric Intensive Care and Neuropaediatrics, Medical University of Vienna, Vienna, Austria
| | - Tobias Werther
- Department of Paediatrics and Adolescent Medicine, Comprehensive Centre for Paediatrics, Division of Neonatology, Paediatric Intensive Care and Neuropaediatrics, Medical University of Vienna, Vienna, Austria
| | - Michael Wagner
- Department of Paediatrics and Adolescent Medicine, Comprehensive Centre for Paediatrics, Division of Neonatology, Paediatric Intensive Care and Neuropaediatrics, Medical University of Vienna, Vienna, Austria
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2
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Pereira-Fantini PM, Kenna KR, Fatmous M, Sett A, Douglas E, Dahm S, Sourial M, Fang H, Greening DW, Tingay DG. Impact of tidal volume strategy at birth on initiating lung injury in preterm lambs. Am J Physiol Lung Cell Mol Physiol 2023; 325:L594-L603. [PMID: 37727901 DOI: 10.1152/ajplung.00159.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 09/05/2023] [Accepted: 09/14/2023] [Indexed: 09/21/2023] Open
Abstract
Tidal ventilation is essential in supporting the transition to air-breathing at birth, but excessive tidal volume (VT) is an important factor in preterm lung injury. Few studies have assessed the impact of specific VT levels on injury development. Here, we used a lamb model of preterm birth to investigate the role of different levels of VT during positive pressure ventilation (PPV) in promoting aeration and initiating early lung injury pathways. VT was delivered as 1) 7 mL/kg throughout (VTstatic), 2) begun at 3 mL/kg and increased to a final VT of 7 mL/kg over 3 min (VTinc), or 3) commenced at 7 mL/kg, decreased to 3 mL/kg, and then returned to 7 mL/kg (VTalt). VT, inflating pressure, lung compliance, and aeration were similar in all groups from 4 min, as was postmortem histology and lung lavage protein concentration. However, transient decrease in VT in the VTalt group caused increased ventilation heterogeneity. Following TMT-based quantitative mass spectrometry proteomics, 1,610 proteins were identified in the lung. Threefold more proteins were significantly altered with VTalt compared with VTstatic or VTinc strategies. Gene set enrichment analysis identified VTalt specific enrichment of immune and angiogenesis pathways and VTstatic enrichment of metabolic processes. Our finding of comparable lung physiology and volutrauma across VT groups challenges the paradigm that there is a need to rapidly aerate the preterm lung at birth. Increased lung injury and ventilation heterogeneity were identified when initial VT was suddenly decreased during respiratory support at birth, further supporting the benefit of a gentle VT approach.NEW & NOTEWORTHY There is little evidence to guide the best tidal volume (VT) strategy at birth. In this study, comparable aeration, lung mechanics, and lung morphology were observed using static, incremental, and alternating VT strategies. However, transient reduction in VT was associated with ventilation heterogeneity and inflammation. Our results suggest that rapidly aerating the preterm lung may not be as clinically critical as previously thought, providing clinicians with reassurance that gently supporting the preterm lung maybe permissible at birth.
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Affiliation(s)
- Prue M Pereira-Fantini
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Kelly R Kenna
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Monique Fatmous
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Arun Sett
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Newborn Services, Joan Kirner Women's and Children's Hospital, Melbourne, Victoria, Australia
- Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Victoria, Australia
| | - Ellen Douglas
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Sophia Dahm
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Magdy Sourial
- Translational Research Unit, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Haoyun Fang
- Molecular Proteomics, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Baker Department of Cardiometabolic Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - David W Greening
- Molecular Proteomics, Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
- Baker Department of Cardiometabolic Health, The University of Melbourne, Melbourne, Victoria, Australia
- Baker Department of Cardiovascular Research, Translation and Implementation, La Trobe University, Melbourne, Victoria, Australia
| | - David G Tingay
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
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3
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Hillman NH, Jobe AH. Preterm lung and brain responses to mechanical ventilation and corticosteroids. J Perinatol 2023; 43:1222-1229. [PMID: 37169913 DOI: 10.1038/s41372-023-01692-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 04/20/2023] [Accepted: 04/28/2023] [Indexed: 05/13/2023]
Abstract
Mechanical ventilation is necessary to maintain oxygenation and ventilation in many preterm infants. Unfortunately, even short periods of mechanical ventilation can cause lung and airway injury, and initiate the lung inflammation that contributes to the development of bronchopulmonary dysplasia (BPD). The mechanical stretch leads to airway cell differentiation and simplification of the alveoli, and releases cytokines that cause systemic response in other organs. Mechanical ventilation also leads to brain injury (IVH, white and gray matter) and neuronal inflammation that can affect the neurodevelopment of preterm infants. In efforts to decrease BPD, corticosteroids have been used for both prevention and treatment of lung inflammation. Corticosteroids have also been demonstrated to cause neuronal injury, so the clinician must balance the negative effects of both mechanical ventilation and steroids on the brain and lungs. Predictive models for BPD can help assess the infants who will benefit most from corticosteroid exposure. This review describes the lung and brain injury from mechanical ventilation in the delivery room and chronic mechanical ventilation in animal models. It provides updates on the current guidelines for use of postnatal corticosteroids (dexamethasone, hydrocortisone, budesonide, budesonide with surfactant) for the prevention and treatment of BPD, and the effects the timing of each steroid regimen has on neurodevelopment.
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Affiliation(s)
- Noah H Hillman
- Division of Neonatology, SSM Health Cardinal Glennon Children's Hospital, Saint Louis University, Saint Louis, MO, 63104, USA.
| | - Alan H Jobe
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH, 45229, USA
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4
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Davies IM, Polglase GR. Inflating or Overinflation? New Evidence for Lung Injury at Birth. Am J Respir Crit Care Med 2023; 208:517-518. [PMID: 37450842 PMCID: PMC10492251 DOI: 10.1164/rccm.202306-1053ed] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 07/14/2023] [Indexed: 07/18/2023] Open
Affiliation(s)
- Indya M Davies
- Department of Obstetrics and Gynaecology Monash University Clayton, Victoria, Australia and The Ritchie Centre Hudson Institute of Medical Research Clayton Victoria, Australia
| | - Graeme R Polglase
- Department of Obstetrics and Gynaecology Monash University Clayton, Victoria, Australia and The Ritchie Centre Hudson Institute of Medical Research Clayton Victoria, Australia
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5
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Tingay DG, Fatmous M, Kenna K, Dowse G, Douglas E, Sett A, Perkins EJ, Sourial M, Pereira-Fantini PM. Inflating Pressure and Not Expiratory Pressure Initiates Lung Injury at Birth in Preterm Lambs. Am J Respir Crit Care Med 2023; 208:589-599. [PMID: 37276583 DOI: 10.1164/rccm.202301-0104oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 05/31/2023] [Indexed: 06/07/2023] Open
Abstract
Rationale: Inflation is essential for aeration at birth, but current inflating pressure settings are without an evidence base. Objectives: To determine the role of inflating pressure (ΔP), and its relationship with positive end-expiratory pressure (PEEP), in initiating early lung injury pathways in the preterm lamb lung. Methods: Preterm (124 to 127 d) steroid-exposed lambs (n = 45) were randomly allocated (8-10 per group) to 15 minutes of respiratory support with placental circulation and 20 or 30 cm H2O ΔP, with an initial high PEEP (maximum, 20 cm H2O) recruitment maneuver known to facilitate aeration (dynamic PEEP), and compared with dynamic PEEP with no ΔP or 30 cm H2O ΔP and low (4 cm H2O) PEEP. Lung mechanics and aeration were measured throughout. After an additional 30 minutes of apneic placental support, lung tissue and bronchoalveolar fluid were analyzed for regional lung injury, including proteomics. Measurements and Main Results: The 30 cm H2O ΔP and dynamic PEEP strategies resulted in quicker aeration and better compliance but higher tidal volumes (often >8 ml/kg, all P < 0.0001; mixed effects) and injury. ΔP 20 cm H2O with dynamic PEEP resulted in the same lung mechanics and aeration, but less energy transmission (tidal mechanical power), as ΔP 30 cm H2O with low PEEP. Dynamic PEEP without any tidal inflations resulted in the least lung injury. Use of any tidal inflating pressures altered metabolic, coagulation and complement protein pathways within the lung. Conclusions: Inflating pressure is essential for the preterm lung at birth, but it is also the primary mediator of lung injury. Greater focus is needed on strategies that identify the safest application of pressure in the delivery room.
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Affiliation(s)
- David G Tingay
- Neonatal Research and
- Translational Research Unit, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics and
| | | | | | | | | | - Arun Sett
- Neonatal Research and
- Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Australia
- Newborn Services, Joan Kirner Women's and Children's, Sunshine Hospital, Western Health, St. Albans, Victoria, Australia
| | | | - Magdy Sourial
- Neonatal Research and
- Translational Research Unit, Murdoch Children's Research Institute, Parkville, Victoria, Australia
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6
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Weisz DE, Yoon E, Dunn M, Emberley J, Mukerji A, Read B, Shah PS. Duration of and trends in respiratory support among extremely preterm infants. Arch Dis Child Fetal Neonatal Ed 2021; 106:286-291. [PMID: 33172875 DOI: 10.1136/archdischild-2020-319496] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 09/11/2020] [Accepted: 10/09/2020] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To evaluate annual trends in the administration and duration of respiratory support among preterm infants. DESIGN Retrospective cohort study. SETTING Tertiary neonatal intensive care units in the Canadian Neonatal Network. PATIENTS 8881 extremely preterm infants born from 2010 to 2017 treated with endotracheal and/or non-invasive positive pressure support (PPS). MAIN OUTCOME MEASURES Competing risks methods were used to investigate the outcomes of mortality and time to first successful extubation, definitive extubation, weaning off PPS, and weaning PPS and/or low-flow oxygen, according to gestational age (GA). Cox proportional hazards and regression models were fitted to evaluate the trend in duration of respiratory support, survival and surfactant treatment over the study period. RESULTS The percentages of infants who died or were weaned from respiratory support were presented graphically over time by GA. Advancing GA was associated with ordinally earlier weaning from respiratory support. Year over year, infants born at 23 weeks were initially and definitively weaned from endotracheal and all PPS earlier (HR 1.06, 95% CI 1.01 to 1.11, for all outcomes), while survival simultaneously increased (OR 1.11, 95% CI 1.03 to 1.18). Infants born at 26 and 27 weeks remained on non-invasive PPS longer (HR 0.97, 95% CI 0.95 to 0.98 and HR 0.97, 95% CI 0.95 to 0.99, respectively). Early surfactant treatment declined among infants born at 24-27 weeks GA. CONCLUSIONS Infants at the borderline of viability have experienced improved survival and earlier weaning from all forms of PPS, while those born at 26 and 27 weeks are spending more time on PPS in recent years. GA-based estimates of the duration of respiratory support and survival may assist in counselling, benchmarking, quality improvement and resource planning.
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Affiliation(s)
- Dany E Weisz
- Newborn and Developmental Paediatrics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada .,Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Eugene Yoon
- Maternal-Infant Care Research Centre, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Michael Dunn
- Newborn and Developmental Paediatrics, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Julie Emberley
- Paediatrics, Janeway Children's Health and Rehabilitation Centre, St John's, Newfoundland and Labrador, Canada
| | - Amit Mukerji
- Paediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Brooke Read
- Paediatrics, London Health Sciences Centre Children's Hospital, London, Ontario, Canada
| | - Prakeshkumar S Shah
- Paediatrics, University of Toronto, Toronto, Ontario, Canada.,Maternal-Infant Care Research Centre, Mount Sinai Hospital, Toronto, Ontario, Canada.,Mount Sinai Hospital, Toronto, Ontario, Canada
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7
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Hillman NH, Abugisisa L, Royse E, Fee E, Kemp MW, Kramer BW, Schmidt AF, Salomone F, Clarke MW, Musk GC, Jobe AH. Dose of budesonide with surfactant affects lung and systemic inflammation after normal and injurious ventilation in preterm lambs. Pediatr Res 2020; 88:726-732. [PMID: 32066138 PMCID: PMC8717708 DOI: 10.1038/s41390-020-0809-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/30/2020] [Accepted: 02/07/2020] [Indexed: 11/09/2022]
Abstract
BACKGROUND The addition of budesonide (Bud) 0.25 mg/kg to surfactant decreased the lung and systemic responses to mechanical ventilation in preterm sheep and the rates and severity of bronchopulmonary dysplasia (BPD) in preterm infants. We hypothesized that lower budesonide concentrations in surfactant will decrease injury while decreasing systemic corticosteroid exposure. METHODS Preterm lambs received either (1) protective tidal volume (VT) ventilation with surfactant from birth or (2) injurious VT ventilation for 15 min and then surfactant treatment. Lambs were further assigned to surfactant mixed with (i) Saline, (ii) Bud 0.25 mg/kg, (iii) Bud 0.1 mg/kg, or (iv) Bud 0.04 mg/kg. All lambs were then ventilated with protective VT for 6 h. RESULTS Plasma Bud levels were proportional to the dose received and decreased throughout ventilation. In both protective and injurious VT ventilation, <4% of Bud remained in the lung at 6 h. Some of the improvements in physiology and markers of injury with Bud 0.25 mg/kg were also found with 0.1 mg/kg, whereas 0.04 mg/kg had only minimal effects. CONCLUSIONS Lower doses of Bud were less effective at decreasing lung and systemic inflammation from mechanical ventilation. The plasma Bud levels were proportional to dose given and the majority left the lung.
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Affiliation(s)
- Noah H Hillman
- Division of Neonatology, Cardinal Glennon Children's Hospital, Saint Louis University, Saint Louis, MO, 63104, USA.
| | - Leenah Abugisisa
- Division of Neonatology, Cardinal Glennon Children’s Hospital, Saint Louis University, Saint Louis, MO 63104
| | - Emily Royse
- Division of Neonatology, Cardinal Glennon Children’s Hospital, Saint Louis University, Saint Louis, MO 63104
| | - Erin Fee
- School of Women’s and Infants’ Health, University of Western Australia, Perth, WA, Australia 6009
| | - Matthew W Kemp
- School of Women’s and Infants’ Health, University of Western Australia, Perth, WA, Australia 6009
| | | | - Augusto F Schmidt
- Department of Pediatrics, Univ. Miami Miller School of Medicine, Miami, FL 33136
| | - Fabrizio Salomone
- Department of Preclinical Pharmacology R&D, Chiesi Farmaceutici S.p.A, Parma, Italy
| | - Michael W Clarke
- Metabolomics Australia, Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA 6009, Australia
| | - Gabrielle C Musk
- School of Women’s and Infants’ Health, University of Western Australia, Perth, WA, Australia 6009,Animal Care Services, University of Western Australia, Perth, WA, Australia 6009
| | - Alan H Jobe
- Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, OH 45229,School of Women’s and Infants’ Health, University of Western Australia, Perth, WA, Australia 6009
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8
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An Artificial Placenta Protects Against Lung Injury and Promotes Continued Lung Development in Extremely Premature Lambs. ASAIO J 2020; 65:690-697. [PMID: 30585874 DOI: 10.1097/mat.0000000000000939] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
An artificial placenta (AP) utilizing extracorporeal life support (ECLS) could protect premature lungs from injury and promote continued development. Preterm lambs at estimated gestational age (EGA) 114-128 days (term = 145) were delivered by Caesarian section and managed in one of three groups: AP, mechanical ventilation (MV), or tissue control (TC). Artificial placenta lambs (114 days EGA, n = 3; 121 days, n = 5) underwent venovenous (VV)-ECLS with jugular drainage and umbilical vein reinfusion for 7 days, with a fluid-filled, occluded airway. Mechanical ventilation lambs (121 days, n = 5; 128 days, n = 5) underwent conventional MV until failure or maximum 48 hours. Tissue control lambs (114 days, n = 3; 121 days, n = 5; 128 days, n = 5) were sacrificed at delivery. At the conclusion of each experiment, lungs were procured and sectioned. Hematoxylin and eosin (H&E) slides were scored 0-4 in seven injury categories, which were summed for a total injury score. Slides were also immunostained for platelet-derived growth factor receptor (PDGFR)-α and α-actin; lung development was quantified by the area fraction of double-positive tips of secondary alveolar septa. Support duration of AP lambs was 163 ± 9 (mean ± SD) hours, 4 ± 3 for early MV lambs, and 40 ± 6 for late MV lambs. Total injury scores at 121 days were 1.7 ± 2.1 for AP vs. 5.5 ± 1.6 for MV (p = 0.02). Using immunofluorescence, double-positive tip area fraction at 121 days was 0.017 ± 0.011 in AP lungs compared with 0.003 ± 0.003 in MV lungs (p < 0.001) and 0.009 ± 0.005 in TC lungs. At 128 days, double-positive tip area fraction was 0.012 ± 0.007 in AP lungs compared with 0.004 ± 0.004 in MV lungs (p < 0.001) and 0.016 ± 0.009 in TC lungs. The AP is protective against lung injury and promotes lung development compared with mechanical ventilation in premature lambs.
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9
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Pereira-Fantini PM, Pang B, Byars SG, Oakley RB, Perkins EJ, Dargaville PA, Davis PG, Nie S, Williamson NA, Ignjatovic V, Tingay DG. Preterm Lung Exhibits Distinct Spatiotemporal Proteome Expression at Initiation of Lung Injury. Am J Respir Cell Mol Biol 2020; 61:631-642. [PMID: 30995072 DOI: 10.1165/rcmb.2019-0084oc] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The development of regional lung injury in the preterm lung is not well understood. This study aimed to characterize time-dependent and regionally specific injury patterns associated with early ventilation of the preterm lung using a mass spectrometry-based proteomic approach. Preterm lambs delivered at 124-127 days gestation received 15 or 90 minutes of mechanical ventilation (positive end-expiratory pressure = 8 cm H2O, Vt = 6-8 ml/kg) and were compared with unventilated control lambs. At study completion, lung tissue was taken from standardized nondependent and dependent regions, and assessed for lung injury via histology, quantitative PCR, and proteomic analysis using Orbitrap-mass spectrometry. Ingenuity pathway analysis software was used to identify temporal and region-specific enrichments in pathways and functions. Apoptotic cell numbers were ninefold higher in nondependent lung at 15 and 90 minutes compared with controls, whereas proliferative cells were increased fourfold in the dependent lung at 90 minutes. The relative gene expression of lung injury markers was increased at 90 minutes in nondependent lung and unchanged in gravity-dependent lung. Within the proteome, the number of differentially expressed proteins was fourfold higher in the nondependent lung than the dependent lung. The number of differential proteins increased over time in both lung regions. A total of 95% of enriched canonical pathways and 94% of enriched cellular and molecular functions were identified only in nondependent lung tissue from the 90-minute ventilation group. In conclusion, complex injury pathways are initiated within the preterm lung after 15 minutes of ventilation and amplified by continuing ventilation. Injury development is region specific, with greater alterations within the proteome of nondependent lung.
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Affiliation(s)
| | | | - Sean G Byars
- Department of Clinical Pathology.,Melbourne Integrative Genomics
| | | | | | - Peter A Dargaville
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Peter G Davis
- Neonatal Research, and.,Department of Obstetrics and Gynaecology, and.,The Royal Women's Hospital, Parkville, Victoria, Australia; and
| | - Shuai Nie
- Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
| | | | - Vera Ignjatovic
- Haematology Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics
| | - David G Tingay
- Neonatal Research, and.,Department of Paediatrics.,Department of Neonatology, Royal Children's Hospital, Parkville, Victoria, Australia
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10
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Tingay DG, Pereira-Fantini PM, Oakley R, McCall KE, Perkins EJ, Miedema M, Sourial M, Thomson J, Waldmann A, Dellaca RL, Davis PG, Dargaville PA. Gradual Aeration at Birth Is More Lung Protective Than a Sustained Inflation in Preterm Lambs. Am J Respir Crit Care Med 2020; 200:608-616. [PMID: 30730759 DOI: 10.1164/rccm.201807-1397oc] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Rationale: The preterm lung is susceptible to injury during transition to air breathing at birth. It remains unclear whether rapid or gradual lung aeration at birth causes less lung injury.Objectives: To examine the effect of gradual and rapid aeration at birth on: 1) the spatiotemporal volume conditions of the lung; and 2) resultant regional lung injury.Methods: Preterm lambs (125 ± 1 d gestation) were randomized at birth to receive: 1) tidal ventilation without an intentional recruitment (no-recruitment maneuver [No-RM]; n = 19); 2) sustained inflation (SI) until full aeration (n = 26); or 3) tidal ventilation with an initial escalating/de-escalating (dynamic) positive end-expiratory pressure (DynPEEP; n = 26). Ventilation thereafter continued for 90 minutes at standardized settings, including PEEP of 8 cm H2O. Lung mechanics and regional aeration and ventilation (electrical impedance tomography) were measured throughout and correlated with histological and gene markers of early lung injury.Measurements and Main Results: DynPEEP significantly improved dynamic compliance (P < 0.0001). An SI, but not DynPEEP or No-RM, resulted in preferential nondependent lung aeration that became less uniform with time (P = 0.0006). The nondependent lung was preferential ventilated by 5 minutes in all groups, with ventilation only becoming uniform with time in the No-RM and DynPEEP groups. All strategies generated similar nondependent lung injury patterns. Only an SI caused greater upregulation of dependent lung gene markers compared with unventilated fetal controls (P < 0.05).Conclusions: Rapidly aerating the preterm lung at birth creates heterogeneous volume states, producing distinct regional injury patterns that affect subsequent tidal ventilation. Gradual aeration with tidal ventilation and PEEP produced the least lung injury.
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Affiliation(s)
- David G Tingay
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia.,Neonatology, The Royal Children's Hospital, Parkville, Victoria, Australia.,Neonatal Research, The Royal Women's Hospital, Parkville, Victoria, Australia.,Department of Paediatrics and
| | - Prue M Pereira-Fantini
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics and
| | - Regina Oakley
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Karen E McCall
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Elizabeth J Perkins
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia.,Neonatology, The Royal Children's Hospital, Parkville, Victoria, Australia
| | - Martijn Miedema
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia.,Neonatology, Amsterdam University Medical Centre, University of Amsterdam, Amsterdam, the Netherlands
| | - Magdy Sourial
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Jessica Thomson
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | | | - Raffaele L Dellaca
- Dipartimento di Elettronica, Informazione e Ingegneria Biomedica, Politecnico di Milano University, Milan, Italy
| | - Peter G Davis
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia.,Neonatal Research, The Royal Women's Hospital, Parkville, Victoria, Australia.,Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Victoria, Australia
| | - Peter A Dargaville
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia.,Neonatal and Paediatric Intensive Care Unit, Royal Hobart Hospital, Hobart, Tasmania, Australia; and.,Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
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11
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Hillman NH, Kothe TB, Schmidt AF, Kemp MW, Royse E, Fee E, Salomone F, Clarke MW, Musk GC, Jobe AH. Surfactant plus budesonide decreases lung and systemic responses to injurious ventilation in preterm sheep. Am J Physiol Lung Cell Mol Physiol 2020; 318:L41-L48. [PMID: 31617728 PMCID: PMC6985873 DOI: 10.1152/ajplung.00203.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 09/09/2019] [Accepted: 09/30/2019] [Indexed: 11/22/2022] Open
Abstract
Mechanical ventilation from birth with normal tidal volumes (VT) causes lung injury and systemic responses in preterm sheep. The addition of budesonide to surfactant therapy decreases these injury markers. Budesonide and surfactant will decrease the injury from injurious VT ventilation in preterm sheep. Lambs at 126 ± 1 day gestational age were ventilated from birth with either: 1) Normal VT [surfactant 200 mg/kg before ventilation, positive end expiratory pressure (PEEP) 5 cmH2O, VT 8 mL/kg] or 2) Injury VT (high pressure, 100% oxygen, no PEEP) for 15 min, then further randomized to surfactant + saline or surfactant + 0.25 mg/kg budesonide with Normal VT for 6 h. Lung function and lung, liver, and brain tissues were evaluated for indicators of injury. Injury VT + saline caused significant injury and systemic responses, and Injury VT + budesonide improved lung physiology. Budesonide decreased lung inflammation and decreased pro-inflammatory cytokine mRNA in the lung, liver, and brain to levels similar to Normal VT + saline. Budesonide was present in plasma within 15 min of treatment in both ventilation groups, and less than 5% of the budesonide remained in the lung at 6 h. mRNA sequencing of liver and periventricular white matter demonstrated multiple pathways altered by both Injury VT and budesonide and the combination exposure. In lambs receiving Injury VT, the addition of budesonide to surfactant improved lung physiology and decreased pro-inflammatory cytokine responses in the lung, liver, and brain to levels similar to lambs receiving Normal VT.
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Affiliation(s)
- Noah H Hillman
- Division of Neonatology, Cardinal Glennon Children's Hospital, Saint Louis University, St. Louis, Missouri
| | - T Brett Kothe
- Division of Neonatology, Cardinal Glennon Children's Hospital, Saint Louis University, St. Louis, Missouri
| | - Augusto F Schmidt
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
| | - Matthew W Kemp
- School of Women's and Infants' Health, University of Western Australia, Perth, Western Australia, Australia
| | - Emily Royse
- Division of Neonatology, Cardinal Glennon Children's Hospital, Saint Louis University, St. Louis, Missouri
| | - Erin Fee
- School of Women's and Infants' Health, University of Western Australia, Perth, Western Australia, Australia
| | - Fabrizio Salomone
- Department of Preclinical Pharmacology R&D, Chiesi Farmaceutici S.p.A, Parma, Italy
| | - Michael W Clarke
- Metabolomics Australia, Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, Western Australia, Australia
| | - Gabrielle C Musk
- School of Women's and Infants' Health, University of Western Australia, Perth, Western Australia, Australia
- Animal Care Services, University of Western Australia, Perth, Western Australia, Australia
| | - Alan H Jobe
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio
- School of Women's and Infants' Health, University of Western Australia, Perth, Western Australia, Australia
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12
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Tingay DG, Togo A, Pereira-Fantini PM, Miedema M, McCall KE, Perkins EJ, Thomson J, Dowse G, Sourial M, Dellacà RL, Davis PG, Dargaville PA. Aeration strategy at birth influences the physiological response to surfactant in preterm lambs. Arch Dis Child Fetal Neonatal Ed 2019; 104:F587-F593. [PMID: 31498776 DOI: 10.1136/archdischild-2018-316240] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/26/2018] [Accepted: 12/19/2018] [Indexed: 11/03/2022]
Abstract
BACKGROUND The influence of pressure strategies to promote lung aeration at birth on the subsequent physiological response to exogenous surfactant therapy has not been investigated. OBJECTIVES To compare the effect of sustained inflation (SI) and a dynamic positive end-expiratory pressure (PEEP) manoeuvre at birth on the subsequent physiological response to exogenous surfactant therapy in preterm lambs. METHODS Steroid-exposed preterm lambs (124-127 days' gestation; n=71) were randomly assigned from birth to either (1) positive-pressure ventilation (PPV) with no recruitment manoeuvre; (2) SI until stable aeration; or (3) 3 min dynamic stepwise PEEP strategy (maximum 14-20 cmH2O; dynamic PEEP (DynPEEP)), followed by PPV for 60 min using a standardised protocol. Surfactant (200 mg/kg poractant alfa) was administered at 10 min. Dynamic compliance, gas exchange and regional ventilation and aeration characteristics (electrical impedance tomography) were measured throughout and compared between groups, and with a historical group (n=38) managed using the same strategies without surfactant. RESULTS Compliance increased after surfactant only in the DynPEEP group (p<0.0001, repeated measures analysis of variance), being 0.17 (0.10, 0.23) mL/kg/cmH2O higher at 60 min than the SI group. An SI resulted in the least uniform aeration, and unlike the no-recruitment and DynPEEP groups, the distribution of aeration and tidal ventilation did not improve with surfactant. All groups had similar improvements in oxygenation post-surfactant compared with the corresponding groups not treated with surfactant. CONCLUSIONS A DynPEEP strategy at birth may improve the response to early surfactant therapy, whereas rapid lung inflation with SI creates non-uniform aeration that appears to inhibit surfactant efficacy.
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Affiliation(s)
- David Gerald Tingay
- Neonatology, Royal Children's Hospital, Parkville, Victoria, Australia.,Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia.,Neonatal Research, The Royal Women's Hospital, Parkville, Victoria, Australia
| | - Andrea Togo
- Neonatology, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Prue M Pereira-Fantini
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Martijn Miedema
- Neonatology, Royal Children's Hospital, Parkville, Victoria, Australia.,Neonatology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Karen E McCall
- Neonatology, Royal Children's Hospital, Parkville, Victoria, Australia.,Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Elizabeth J Perkins
- Neonatology, Royal Children's Hospital, Parkville, Victoria, Australia.,Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Jessica Thomson
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Georgie Dowse
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Magdy Sourial
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Raffaele L Dellacà
- TBM Lab, Dipartimento di Elettronica, Informazione e BioIngegneria (DEIB), Politecnico di Milano University, Milan, Italy
| | - Peter G Davis
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Neonatal Research, The Royal Women's Hospital, Parkville, Victoria, Australia.,Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Victoria, Australia
| | - Peter Anderson Dargaville
- Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Neonatal and Paediatric Intensive Care Unit, Royal Hobart Hospital, Hobart, Tasmania, Australia.,Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
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13
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Oakley RB, Tingay DG, McCall KE, Perkins EJ, Sourial M, Dargaville PA, Pereira-Fantini PM. Gestational Age Influences the Early Microarchitectural Changes in Response to Mechanical Ventilation in the Preterm Lamb Lung. Front Pediatr 2019; 7:325. [PMID: 31497582 PMCID: PMC6712425 DOI: 10.3389/fped.2019.00325] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/19/2019] [Indexed: 11/13/2022] Open
Abstract
Background: Preterm birth is associated with abnormal lung architecture, and a reduction in pulmonary function related to the degree of prematurity. A thorough understanding of the impact of gestational age on lung microarchitecture requires reproducible quantitative analysis of lung structure abnormalities. The objectives of this study were (1) to use quantitative histological software (ImageJ) to map morphological patterns of injury resulting from delivery of an identical ventilation strategy to the lung at varying gestational ages and (2) to identify associations between gestational age-specific morphological alterations and key functional outcomes. Method: Lung morphology was compared after 60 min of a standardized ventilation protocol (40 cm H2O sustained inflation and then volume-targeted positive pressure ventilation with positive end-expiratory pressure 8 cm H2O) in lambs at different gestations (119, 124, 128, 133, 140d) representing the spectrum of premature developmental lung states and the term lung. Age-matched controls were compared at 124 and 128d gestation. Automated and manual functions of Image J were used to measure key histological features. Correlation analysis compared morphological and functional outcomes in lambs aged ≤128 and >128d. Results: In initial studies, unventilated lung was indistinguishable at 124 and 128d. Ventilated lung from lambs aged 124d gestation exhibited increased numbers of detached epithelial cells and lung tissue compared with 128d lambs. Comparing results from saccular to alveolar development (120-140d), lambs aged ≤124d exhibited increased lung tissue, average alveolar area, and increased numbers of detached epithelial cells. Alveolar septal width was increased in lambs aged ≤128d. These findings were mirrored in the measures of gas exchange, lung mechanics, and molecular markers of lung injury. Correlation analysis confirmed the gestation-specific relationships between the histological assessments and functional measures in ventilated lambs at gestation ≤128 vs. >128d. Conclusion: Image J allowed rapid, quantitative assessment of alveolar morphology, and lung injury in the preterm lamb model. Gestational age-specific patterns of injury in response to delivery of an identical ventilation strategy were identified, with 128d being a transition point for associations between morphological alterations and functional outcomes. These results further support the need to develop individualized respiratory support approaches tailored to both the gestational age of the infant and their underlying injury response.
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Affiliation(s)
- Regina B Oakley
- Neonatal Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - David G Tingay
- Neonatal Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia.,Department of Neonatology, Royal Children's Hospital, Parkville, VIC, Australia.,Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
| | - Karen E McCall
- Neonatal Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia.,School of Medicine and Medicinal Sciences, University College Dublin, Dublin, Ireland
| | - Elizabeth J Perkins
- Neonatal Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - Magdy Sourial
- Neonatal Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia
| | - Peter A Dargaville
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Prue M Pereira-Fantini
- Neonatal Research Group, Murdoch Children's Research Institute, Parkville, VIC, Australia.,Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
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14
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Alvira CM, Morty RE. Can We Understand the Pathobiology of Bronchopulmonary Dysplasia? J Pediatr 2017; 190:27-37. [PMID: 29144252 PMCID: PMC5726414 DOI: 10.1016/j.jpeds.2017.08.041] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 07/28/2017] [Accepted: 08/16/2017] [Indexed: 01/17/2023]
Affiliation(s)
- Cristina M. Alvira
- Center for Excellence in Pulmonary Biology, Department of Pediatrics, Stanford University School of Medicine, Palo Alto, California 94305
| | - Rory E. Morty
- Department of Internal Medicine (Pulmonology), University of Giessen and Marburg Lung Center campus of the German Center for Lung Research, Giessen, Germany,Department of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
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15
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Gisslen T, Alvarez M, Wells C, Soo MT, Lambers DS, Knox CL, Meinzen-Derr JK, Chougnet CA, Jobe AH, Kallapur SG. Fetal inflammation associated with minimal acute morbidity in moderate/late preterm infants. Arch Dis Child Fetal Neonatal Ed 2016; 101:F513-F519. [PMID: 27010018 DOI: 10.1136/archdischild-2015-308518] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 10/30/2015] [Accepted: 02/24/2016] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To determine whether exposure to acute chorioamnionitis and fetal inflammation caused short-term adverse outcomes. DESIGN This is a prospective observational study: subjects were mothers delivering at 32-36 weeks gestation and their preterm infants at a large urban tertiary level III perinatal unit (N=477 infants). Placentae and fetal membranes were scored for acute histological chorioamnionitis based on the Redline criteria. Fetal inflammation was characterised by histological diagnosis of funisitis (umbilical cord inflammation), increased cord blood cytokines measured by ELISA, and activation of the inflammatory cells infiltrating the placenta and fetal membranes measured by immunohistology. Maternal and infant data were collected. RESULTS Twenty-four per cent of 32-36-week infants were exposed to histological chorioamnionitis and 6.9% had funisitis. Immunostaining for leucocyte subsets showed selective infiltration of the placenta and fetal membranes with activated neutrophils and macrophages with chorioamnionitis. Interleukin (IL) 6, IL-8 and granulocyte colony-stimulating factor were selectively increased in the cord blood of preterm infants with funisitis. Compared with infants without chorioamnionitis, funisitis was associated with increased ventilation support during resuscitation (43.8% vs 15.4%) and more respiratory distress syndrome postnatally (27.3% vs 10.2%) in univariate analysis. However, these associations disappeared after adjusting for prematurity. CONCLUSIONS Despite fetal exposure to funisitis, increased cord blood cytokines and activated placental inflammatory cells, we could not demonstrate neonatal morbidity specifically attributable to fetal inflammation after adjusting for gestational age in moderate and late preterm infants.
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Affiliation(s)
- Tate Gisslen
- Divisions of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Division of Neonatology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Manuel Alvarez
- Divisions of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Casey Wells
- Department of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Man-Ting Soo
- Divisions of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, Kwong Wah Hospital, Hong Kong, Hong Kong
| | - Donna S Lambers
- Department of Obstetrics and Gynecology, Good Samaritan Hospital, Cincinnati, Ohio, USA
| | - Christine L Knox
- Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, Brisbane, Australia
| | - Jareen K Meinzen-Derr
- Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Claire A Chougnet
- Department of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Alan H Jobe
- Divisions of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Suhas G Kallapur
- Divisions of Neonatology and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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16
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Prakash YS. Emerging concepts in smooth muscle contributions to airway structure and function: implications for health and disease. Am J Physiol Lung Cell Mol Physiol 2016; 311:L1113-L1140. [PMID: 27742732 DOI: 10.1152/ajplung.00370.2016] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/06/2016] [Indexed: 12/15/2022] Open
Abstract
Airway structure and function are key aspects of normal lung development, growth, and aging, as well as of lung responses to the environment and the pathophysiology of important diseases such as asthma, chronic obstructive pulmonary disease, and fibrosis. In this regard, the contributions of airway smooth muscle (ASM) are both functional, in the context of airway contractility and relaxation, as well as synthetic, involving production and modulation of extracellular components, modulation of the local immune environment, cellular contribution to airway structure, and, finally, interactions with other airway cell types such as epithelium, fibroblasts, and nerves. These ASM contributions are now found to be critical in airway hyperresponsiveness and remodeling that occur in lung diseases. This review emphasizes established and recent discoveries that underline the central role of ASM and sets the stage for future research toward understanding how ASM plays a central role by being both upstream and downstream in the many interactive processes that determine airway structure and function in health and disease.
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Affiliation(s)
- Y S Prakash
- Departments of Anesthesiology, and Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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17
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Tracy M, Shah D, Priyadarshi A, Hinder M. The effectiveness of Ambu neonatal self-inflating bag to provide consistent positive end-expiratory pressure. Arch Dis Child Fetal Neonatal Ed 2016; 101:F439-43. [PMID: 26785860 DOI: 10.1136/archdischild-2015-308649] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 12/22/2015] [Indexed: 11/03/2022]
Abstract
BACKGROUND The self-inflating bag (SIB) is the most common device used to resuscitate newborn infants worldwide. Delivering positive end-expiratory pressure (PEEP) may be important in infant resuscitation and limited research using one brand (Laerdal) SIB has led to international guidelines stating SIBs 'often deliver inconsistent positive end-expiratory pressure'. AIM To measure delivered PEEP using disposable and reusable Ambu SIBs fitted with Ambu PEEP valve and manometer comparing different rates of 20, 40 and 60 inflations per minute (IPM) and test lung compliance. DESIGN Three experienced neonatal medical staff provided positive pressure ventilation each using different disposable and reusable Ambu SIBs, targeting peak inflation pressure of 30-35 cm H2O at three different set PEEP levels of 5, 7.5 and 10 cm H2O on test lungs of compliance of 0.5 and 3.0 mL/cm H2O. Inflation data were captured with Florian Monitor and analysed by analysis of variance for repeated measures. RESULTS A total of 3265 inflations were analysed. The delivered PEEP was rate and lung compliance dependent. At set PEEP of 5 cm H2O, the adjusted measured PEEP was 3.6, 4.4 and 4.8 cm H2O at rates 20, 40 and 60 IPM, respectively, while at set PEEP of 10 cm H2O, the adjusted measured PEEP was 7.0, 8.8 and 9.8 cm H2O. The delivered PEEP was statistically higher with more compliant test lungs. CONCLUSIONS The Ambu SIB with Ambu PEEP valve can deliver consistent mean levels of PEEP close to the operator set PEEP. The performance of SIB with PEEP valves is likely brand specific and requires further evaluation.
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Affiliation(s)
- Mark Tracy
- Neonatal Intensive Care, Westmead Hospital, Westmead, New South Wales, Australia Department of Paediatrics and Child Health, Sydney University, Westmead, New South Wales, Australia
| | - Dharmesh Shah
- Neonatal Intensive Care, Westmead Hospital, Westmead, New South Wales, Australia Sydney University, New South Wales, Australia
| | - Archana Priyadarshi
- Neonatal Intensive Care, Westmead Hospital, Westmead, New South Wales, Australia Sydney University, New South Wales, Australia
| | - Murray Hinder
- Neonatal Intensive Care, Westmead Hospital, Westmead, New South Wales, Australia Sydney University, New South Wales, Australia
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18
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Petersen RY, Royse E, Kemp MW, Miura Y, Noe A, Jobe AH, Hillman NH. Distending Pressure Did Not Activate Acute Phase or Inflammatory Responses in the Airways and Lungs of Fetal, Preterm Lambs. PLoS One 2016; 11:e0159754. [PMID: 27463520 PMCID: PMC4962990 DOI: 10.1371/journal.pone.0159754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/06/2016] [Indexed: 11/18/2022] Open
Abstract
Background Mechanical ventilation at birth causes airway injury and lung inflammation in preterm sheep. Continuous positive airway pressure (CPAP) is being increasingly used clinically to transition preterm infants at birth. Objective To test if distending pressures will activate acute phase reactants and inflammatory changes in the airways of fetal, preterm lambs. Methods The head and chest of fetal lambs at 128±1 day GA were surgically exteriorized. With placental circulation intact, fetal lambs were then randomized to one of five 15 minute interventions: PEEP of 0, 4, 8, 12, or 16 cmH2O. Recruitment volumes were recorded. Fetal lambs remained on placental support for 30 min after the intervention. The twins of each 0 cmH2O animal served as controls. Fetal lung fluid (FLF), bronchoalveolar lavage fluid (BAL), right mainstem bronchi and peripheral lung tissue were evaluated for inflammation. Results Recruitment volume increased from 0.4±0.04 mL/kg at 4 cmH2O to 2.4±0.3 mL/kg at 16 cmH2O. The lambs were surfactant deficient, and all pressures were below the opening inflection pressure on pressure-volume curve. mRNA expression of early response genes and pro-inflammatory cytokines did not increase in airway tissue or lung tissue at any pressure compared to controls. FLF and BAL also did not have increases in early response proteins. No histologic changes or Egr-1 activation was present at the pressures used. Conclusion Distending pressures as high as 16 cmH2O did not recruit lung volume at birth and did not increase markers of injury in the lung or airways in non-breathing preterm fetal sheep.
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Affiliation(s)
- Rebecca Y. Petersen
- Division of Neonatology, Cardinal Glennon Children’s Hospital, Saint Louis University, Saint Louis, MO, 63104, United States of America
| | - Emily Royse
- Division of Neonatology, Cardinal Glennon Children’s Hospital, Saint Louis University, Saint Louis, MO, 63104, United States of America
| | - Matthew W. Kemp
- School of Women and Infants’ Health, University of Western Australia, Perth, WA, 6009, Australia
| | - Yuichiro Miura
- School of Women and Infants’ Health, University of Western Australia, Perth, WA, 6009, Australia
| | - Andres Noe
- School of Women and Infants’ Health, University of Western Australia, Perth, WA, 6009, Australia
| | - Alan H. Jobe
- Division of Pulmonary Biology, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, OH, 45229, United States of America
- School of Women and Infants’ Health, University of Western Australia, Perth, WA, 6009, Australia
| | - Noah H. Hillman
- Division of Neonatology, Cardinal Glennon Children’s Hospital, Saint Louis University, Saint Louis, MO, 63104, United States of America
- * E-mail:
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19
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Ramos-Navarro C, Sanchez-Luna M, Sanz-López E, Maderuelo-Rodriguez E, Zamora-Flores E. Effectiveness of Synchronized Noninvasive Ventilation to Prevent Intubation in Preterm Infants. AJP Rep 2016; 6:e264-71. [PMID: 27500013 PMCID: PMC4974112 DOI: 10.1055/s-0036-1586205] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Noninvasive ventilation is being increasingly used on preterm infants to reduce ventilator lung injury and bronchopulmonary dysplasia. The aim of this study was to evaluate the effectiveness of synchronized nasal intermittent positive pressure ventilation (SNIPPV) to prevent intubation in premature infants. METHODS Prospective observational study of SNIPPV use on preterm infants of less than 32 weeks' gestation. All patients were managed using a prospective protocol intended to reduce invasive mechanical ventilation (iMV) use. Previous respiratory status, as well as respiratory outcomes and possible secondary side effects were analyzed. RESULTS SNIPPV was used on 78 patients: electively to support extubation on 25 ventilator-dependent patients and as a rescue therapy after nasal continuous positive airway pressure failure on 53 patients. For 92% of patients in the elective group and 66% in the rescue group, iMV was avoided over the following 72 hours. No adverse effects were detected, and all patients were in a stable condition even if intubation was eventually needed. CONCLUSIONS The application of SNIPPV in place of or to remove mechanical ventilation avoids intubation in 74.4% of preterm infants with respiratory failure. No adverse effects were detected.
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Affiliation(s)
- Cristina Ramos-Navarro
- Neonatology Division, Department of Pediatrics, Gregorio Marañon Biomedical Research Institute, Gregorio Marañon University Hospital, Complutense University, Madrid, Spain
| | - Manuel Sanchez-Luna
- Neonatology Division, Department of Pediatrics, Gregorio Marañon Biomedical Research Institute, Gregorio Marañon University Hospital, Complutense University, Madrid, Spain
| | - Ester Sanz-López
- Neonatology Division, Department of Pediatrics, Gregorio Marañon Biomedical Research Institute, Gregorio Marañon University Hospital, Complutense University, Madrid, Spain
| | - Elena Maderuelo-Rodriguez
- Neonatology Division, Department of Pediatrics, Gregorio Marañon Biomedical Research Institute, Gregorio Marañon University Hospital, Complutense University, Madrid, Spain
| | - Elena Zamora-Flores
- Neonatology Division, Department of Pediatrics, Gregorio Marañon Biomedical Research Institute, Gregorio Marañon University Hospital, Complutense University, Madrid, Spain
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20
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Deptula N, Royse E, Kemp MW, Miura Y, Kallapur SG, Jobe AH, Hillman NH. Brief mechanical ventilation causes differential epithelial repair along the airways of fetal, preterm lambs. Am J Physiol Lung Cell Mol Physiol 2016; 311:L412-20. [PMID: 27343193 PMCID: PMC5142451 DOI: 10.1152/ajplung.00181.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 06/20/2016] [Indexed: 02/01/2023] Open
Abstract
Mechanical ventilation of preterm lambs causes lung inflammation and injury to the airway epithelium, which is repaired by 15 days after ventilation. In mice, activated basal cells (p63+, KRT14+, KRT8+) initiate injury repair to the trachea, whereas club cells coordinate distal airway repair. In both human and sheep, basal cells line the pseudostratified airways to the distal bronchioles with club cells only present in terminal bronchioles. Mechanical ventilation causes airway epithelial injury that is repaired through basal cell activation in the fetal lung. Ewes at 123 ± 1 day gestational age had the head and chest of the fetus exteriorized and tracheostomy placed. With placental circulation intact, fetal lambs were mechanically ventilated with up to 15 ml/kg for 15 min with 95% N2/5% CO2 Fetal lambs were returned to the uterus for up to 24 h. The trachea, left mainstem bronchi, and peripheral lung were evaluated for epithelial injury and cellular response consistent with repair. Peripheral lung tissue had inflammation, pro-inflammatory cytokine production, epithelial growth factor receptor ligand upregulation, increased p63 expression, and proliferation of pro-SPB, TTF-1 positive club cells. In bronchi, KRT14 and KRT8 mRNA increased without increases in Notch pathway mRNA or proliferation. In trachea, mRNA increased for Notch ligands, SAM pointed domain-containing Ets transcription factor and mucin 5B, but not for basal cell markers. A brief period of mechanical ventilation causes differential epithelial activation between trachea, bronchi, and peripheral lung. The repair mechanisms identified in adult mice occur at different levels of airway branching in fetal sheep with basal and club cell activation.
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Affiliation(s)
- Nicole Deptula
- Division of Neonatology, Cardinal Glennon Children's Hospital, Saint Louis University, Saint Louis, Missouri
| | - Emily Royse
- Division of Neonatology, Cardinal Glennon Children's Hospital, Saint Louis University, Saint Louis, Missouri
| | - Matthew W Kemp
- School of Women's and Infants' Health, University of Western Australia, Perth, Australia
| | - Yuichiro Miura
- School of Women's and Infants' Health, University of Western Australia, Perth, Australia
| | - Suhas G Kallapur
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio; and School of Women's and Infants' Health, University of Western Australia, Perth, Australia
| | - Alan H Jobe
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio; and School of Women's and Infants' Health, University of Western Australia, Perth, Australia
| | - Noah H Hillman
- Division of Neonatology, Cardinal Glennon Children's Hospital, Saint Louis University, Saint Louis, Missouri;
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Pereira-Fantini PM, Rajapaksa AE, Oakley R, Tingay DG. Selection of Reference Genes for Gene Expression Studies related to lung injury in a preterm lamb model. Sci Rep 2016; 6:26476. [PMID: 27210246 PMCID: PMC4876477 DOI: 10.1038/srep26476] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/04/2016] [Indexed: 12/13/2022] Open
Abstract
Preterm newborns often require invasive support, however even brief periods of supported ventilation applied inappropriately to the lung can cause injury. Real-time quantitative reverse transcriptase-PCR (qPCR) has been extensively employed in studies of ventilation-induced lung injury with the reference gene 18S ribosomal RNA (18S RNA) most commonly employed as the internal control reference gene. Whilst the results of these studies depend on the stability of the reference gene employed, the use of 18S RNA has not been validated. In this study the expression profile of five candidate reference genes (18S RNA, ACTB, GAPDH, TOP1 and RPS29) in two geographical locations, was evaluated by dedicated algorithms, including geNorm, Normfinder, Bestkeeper and ΔCt method and the overall stability of these candidate genes determined (RefFinder). Secondary studies examined the influence of reference gene choice on the relative expression of two well-validated lung injury markers; EGR1 and IL1B. In the setting of the preterm lamb model of lung injury, RPS29 reference gene expression was influenced by tissue location; however we determined that individual ventilation strategies influence reference gene stability. Whilst 18S RNA is the most commonly employed reference gene in preterm lamb lung studies, our results suggest that GAPDH is a more suitable candidate.
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Affiliation(s)
| | - Anushi E Rajapaksa
- Neonatal Research Group, Murdoch Childrens Research Institute, Parkville, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Australia
| | - Regina Oakley
- Neonatal Research Group, Murdoch Childrens Research Institute, Parkville, Australia
| | - David G Tingay
- Neonatal Research Group, Murdoch Childrens Research Institute, Parkville, Australia.,Department of Neonatology, Royal Children's Hospital, Parkville, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Australia
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Arrindell EL, Krishnan R, van der Merwe M, Caminita F, Howard SC, Zhang J, Buddington RK. Lung volume recruitment in a preterm pig model of lung immaturity. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1088-92. [PMID: 26408557 DOI: 10.1152/ajplung.00292.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 09/17/2015] [Indexed: 12/22/2022] Open
Abstract
A translational preterm pig model analogous to infants born at 28 wk of gestation revealed that continuous positive airway pressure results in limited lung recruitment but does not prevent respiratory distress syndrome, whereas assist-control + volume guarantee (AC+VG) ventilation improves recruitment but can cause injury, highlighting the need for improved ventilation strategies. We determined whether airway pressure release ventilation (APRV) can be used to recruit the immature lungs of preterm pigs without injury. Spontaneously breathing pigs delivered at 89% of term (model for 28-wk infants) were randomized to 24 h of APRV (n = 9) vs. AC+VG with a tidal volume of 5 ml/kg (n = 10). Control pigs (n = 36) were provided with supplemental oxygen by an open mask. Nutrition and fluid support was provided throughout the 24-h period. All pigs supported with APRV and AC+VG survived 24 h, compared with 62% of control pigs. APRV resulted in improved lung volume recruitment compared with AC+VG based on radiographs, lower Pco2 levels (44 ± 2.9 vs. 53 ± 2.7 mmHg, P = 0.009) and lower inspired oxygen fraction requirements (36 ± 6 vs. 44 ± 11%, P < 0.001), and higher oxygenation index (5.1 ± 1.5 vs. 2.9 ± 1.1, P = 0.001). There were no differences between APRV and AC+VG pigs for heart rate, ratio of wet to dry lung mass, proinflammatory cytokines, or histopathological markers of lung injury. Lung protective ventilation with APRV improved recruitment of alveoli of preterm lungs, enhanced development and maintenance of functional residual capacity without injury, and improved clinical outcomes relative to AC+VG. Long-term consequences of lung volume recruitment by using APRV should be evaluated.
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Affiliation(s)
- Esmond L Arrindell
- Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Ramesh Krishnan
- Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | | | - Scott C Howard
- School of Health Studies, University of Memphis, Memphis, Tennessee
| | - Jie Zhang
- Pathology, University of Tennessee Health Science Center, Memphis, Tennessee
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Jobe AH. Animal Models, Learning Lessons to Prevent and Treat Neonatal Chronic Lung Disease. Front Med (Lausanne) 2015; 2:49. [PMID: 26301222 PMCID: PMC4528292 DOI: 10.3389/fmed.2015.00049] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 07/14/2015] [Indexed: 11/23/2022] Open
Abstract
Bronchopulmonary dysplasia (BPD) is a unique injury syndrome caused by prolonged injury and repair imposed on an immature and developing lung. The decreased septation and decreased microvascular development phenotype of BPD can be reproduced in newborn rodents with increased chronic oxygen exposure and in premature primates and sheep with oxygen and/or mechanical ventilation. The inflammation caused by oxidants, inflammatory agonists, and/or stretch injury from mechanical ventilation seems to promote the anatomic abnormalities. Multiple interventions targeted to specific inflammatory cells or pathways or targeted to decreasing ventilation-mediated injury can substantially prevent the anatomic changes associated with BPD in term rodents and in preterm sheep or primate models. Most of the anti-inflammatory therapies with benefit in animal models have not been tested clinically. None of the interventions that have been tested clinically are as effective as anticipated from the animal models. These inconsistencies in responses likely are explained by the antenatal differences in lung exposures of the developing animals relative to very preterm humans. The animals generally have normal lungs while the lungs of preterm infants are exposed variably to intrauterine inflammation, growth abnormalities, antenatal corticosteroids, and poorly understood effects from the causes of preterm delivery. The animal models have been essential for the definition of the mediators that can cause a BPD phenotype. These models will be necessary to develop and test future-targeted interventions to prevent and treat BPD.
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Affiliation(s)
- Alan H Jobe
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati , Cincinnati, OH , USA
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Barton SK, Tolcos M, Miller SL, Roehr CC, Schmölzer GM, Davis PG, Moss TJM, LaRosa DA, Hooper SB, Polglase GR. Unraveling the Links Between the Initiation of Ventilation and Brain Injury in Preterm Infants. Front Pediatr 2015; 3:97. [PMID: 26618148 PMCID: PMC4639621 DOI: 10.3389/fped.2015.00097] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/26/2015] [Indexed: 11/13/2022] Open
Abstract
The initiation of ventilation in the delivery room is one of the most important but least controlled interventions a preterm infant will face. Tidal volumes (V T) used in the neonatal intensive care unit are carefully measured and adjusted. However, the V Ts that an infant receives during resuscitation are usually unmonitored and highly variable. Inappropriate V Ts delivered to preterm infants during respiratory support substantially increase the risk of injury and inflammation to the lungs and brain. These may cause cerebral blood flow instability and initiate a cerebral inflammatory cascade. The two pathways increase the risk of brain injury and potential life-long adverse neurodevelopmental outcomes. The employment of new technologies, including respiratory function monitors, can improve and guide the optimal delivery of V Ts and reduce confounders, such as leak. Better respiratory support in the delivery room has the potential to improve both respiratory and neurological outcomes in this vulnerable population.
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Affiliation(s)
- Samantha K Barton
- The Ritchie Centre, Hudson Institute of Medical Research , Melbourne, VIC , Australia
| | - Mary Tolcos
- The Ritchie Centre, Hudson Institute of Medical Research , Melbourne, VIC , Australia ; Department of Obstetrics and Gynecology, Monash University , Melbourne, VIC , Australia
| | - Suzie L Miller
- The Ritchie Centre, Hudson Institute of Medical Research , Melbourne, VIC , Australia ; Department of Obstetrics and Gynecology, Monash University , Melbourne, VIC , Australia
| | - Charles C Roehr
- The Ritchie Centre, Hudson Institute of Medical Research , Melbourne, VIC , Australia ; Newborn Services, John Radcliffe Hospital, Oxford University Hospitals , Oxford , UK
| | - Georg M Schmölzer
- Department of Pediatrics, University of Alberta , Edmonton, AB , Canada ; Centre for the Study of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Alberta Health Services , Edmonton, AB , Canada
| | - Peter G Davis
- Neonatal Services, Newborn Research Centre, The Royal Women's Hospital , Melbourne, VIC , Australia
| | - Timothy J M Moss
- The Ritchie Centre, Hudson Institute of Medical Research , Melbourne, VIC , Australia ; Department of Obstetrics and Gynecology, Monash University , Melbourne, VIC , Australia
| | - Domenic A LaRosa
- The Ritchie Centre, Hudson Institute of Medical Research , Melbourne, VIC , Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research , Melbourne, VIC , Australia ; Department of Obstetrics and Gynecology, Monash University , Melbourne, VIC , Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research , Melbourne, VIC , Australia ; Department of Obstetrics and Gynecology, Monash University , Melbourne, VIC , Australia
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Hillman NH, Kemp MW, Miura Y, Kallapur SG, Jobe AH. Sustained inflation at birth did not alter lung injury from mechanical ventilation in surfactant-treated fetal lambs. PLoS One 2014; 9:e113473. [PMID: 25419969 PMCID: PMC4242618 DOI: 10.1371/journal.pone.0113473] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 10/23/2014] [Indexed: 01/10/2023] Open
Abstract
Background Sustained inflations (SI) are used with the initiation of ventilation at birth to rapidly recruit functional residual capacity and may decrease lung injury and the need for mechanical ventilation in preterm infants. However, a 20 second SI in surfactant-deficient preterm lambs caused an acute phase injury response without decreasing lung injury from subsequent mechanical ventilation. Hypothesis A 20 second SI at birth will decrease lung injury from mechanical ventilation in surfactant-treated preterm fetal lambs. Methods The head and chest of fetal sheep at 126±1 day GA were exteriorized, with tracheostomy and removal of fetal lung fluid prior to treatment with surfactant (300 mg in 15 ml saline). Fetal lambs were randomized to one of four 15 minute interventions: 1) PEEP 8 cmH2O; 2) 20 sec SI at 40 cmH2O, then PEEP 8 cmH2O; 3) mechanical ventilation with 7 ml/kg tidal volume; or 4) 20 sec SI then mechanical ventilation at 7 ml/kg. Fetal lambs remained on placental support for the intervention and for 30 min after the intervention. Results SI recruited a mean volume of 6.8±0.8 mL/kg. SI did not alter respiratory physiology during mechanical ventilation. Heat shock protein (HSP) 70, HSP60, and total protein in lung fluid similarly increased in both ventilation groups. Modest pro-inflammatory cytokine and acute phase responses, with or without SI, were similar with ventilation. SI alone did not increase markers of injury. Conclusion In surfactant treated fetal lambs, a 20 sec SI did not alter ventilation physiology or markers of lung injury from mechanical ventilation.
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Affiliation(s)
- Noah H. Hillman
- Division of Neonatology, Cardinal Glennon Children's Medical Center, Saint Louis University, Saint Louis, Missouri, United States of America
- * E-mail:
| | - Matthew W. Kemp
- School of Women's and Infants' Health, University of Western Australia, Perth, Western Australia, Australia
| | - Yuichiro Miura
- School of Women's and Infants' Health, University of Western Australia, Perth, Western Australia, Australia
| | - Suhas G. Kallapur
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, United States of America
- School of Women's and Infants' Health, University of Western Australia, Perth, Western Australia, Australia
| | - Alan H. Jobe
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio, United States of America
- School of Women's and Infants' Health, University of Western Australia, Perth, Western Australia, Australia
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Barton SK, Moss TJM, Hooper SB, Crossley KJ, Gill AW, Kluckow M, Zahra V, Wong FY, Pichler G, Galinsky R, Miller SL, Tolcos M, Polglase GR. Protective ventilation of preterm lambs exposed to acute chorioamnionitis does not reduce ventilation-induced lung or brain injury. PLoS One 2014; 9:e112402. [PMID: 25379714 PMCID: PMC4224447 DOI: 10.1371/journal.pone.0112402] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 10/15/2014] [Indexed: 01/25/2023] Open
Abstract
Background The onset of mechanical ventilation is a critical time for the initiation of cerebral white matter (WM) injury in preterm neonates, particularly if they are inadvertently exposed to high tidal volumes (VT) in the delivery room. Protective ventilation strategies at birth reduce ventilation-induced lung and brain inflammation and injury, however its efficacy in a compromised newborn is not known. Chorioamnionitis is a common antecedent of preterm birth, and increases the risk and severity of WM injury. We investigated the effects of high VT ventilation, after chorioamnionitis, on preterm lung and WM inflammation and injury, and whether a protective ventilation strategy could mitigate the response. Methods Pregnant ewes (n = 18) received intra-amniotic lipopolysaccharide (LPS) 2 days before delivery, instrumentation and ventilation at 127±1 days gestation. Lambs were either immediately euthanased and used as unventilated controls (LPSUVC; n = 6), or were ventilated using an injurious high VT strategy (LPSINJ; n = 5) or a protective ventilation strategy (LPSPROT; n = 7) for a total of 90 min. Mean arterial pressure, heart rate and cerebral haemodynamics and oxygenation were measured continuously. Lungs and brains underwent molecular and histological assessment of inflammation and injury. Results LPSINJ lambs had poorer oxygenation than LPSPROT lambs. Ventilation requirements and cardiopulmonary and systemic haemodynamics were not different between ventilation strategies. Compared to unventilated lambs, LPSINJ and LPSPROT lambs had increases in pro-inflammatory cytokine expression within the lungs and brain, and increased astrogliosis (p<0.02) and cell death (p<0.05) in the WM, which were equivalent in magnitude between groups. Conclusions Ventilation after acute chorioamnionitis, irrespective of strategy used, increases haemodynamic instability and lung and cerebral inflammation and injury. Mechanical ventilation is a potential contributor to WM injury in infants exposed to chorioamnionitis.
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Affiliation(s)
- Samantha K. Barton
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Timothy J. M. Moss
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
- Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, 3168, Australia
| | - Stuart B. Hooper
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
- Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, 3168, Australia
| | - Kelly J. Crossley
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Andrew W. Gill
- School of Women's and Infants' Health, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Martin Kluckow
- Department of Neonatal Medicine, Royal North Shore Hospital and University of Sydney, Sydney, New South Wales, 2065, Australia
| | - Valerie Zahra
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Flora Y. Wong
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Gerhard Pichler
- Department of Pediatrics, Medical University Graz, Auenbruggerplatz 30, Graz, Austria, 8036
| | - Robert Galinsky
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Suzanne L. Miller
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
- Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, 3168, Australia
| | - Mary Tolcos
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
| | - Graeme R. Polglase
- The Ritchie Centre, MIMR-PHI Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia
- Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, 3168, Australia
- * E-mail:
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Iyer NP, Mhanna MJ. The role of surfactant and non-invasive mechanical ventilation in early management of respiratory distress syndrome in premature infants. World J Pediatr 2014; 10:204-10. [PMID: 25124970 DOI: 10.1007/s12519-014-0494-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 03/26/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Surfactant replacement therapy has been used for few decades for the treatment of respiratory distress syndrome (RDS) and has significantly improved morbidity and mortality in premature infants. Non-invasive respiratory support has recently emerged as a strategy in the early management of RDS. In this review, we discuss the different strategies of early management of RDS. DATA SOURCES A literature search of PubMed database was conducted to review the subject. The quality of evidence of key clinical studies was graded according to a modified grading system of the international GRADE group. RESULTS Continuous positive airway pressure (CPAP) with selective surfactant is a safe alternative to routine intubation, surfactant and mechanical ventilation in preterm infants with spontaneous breathing, and such an approach has been associated with decreased risk of death and bronchopulmonary dysplasia. There is a risk of pneumothorax when using a high pressure of CPAP (≥8 cm of H2O), a high partial pressure of carbon dioxide (PCO2 >75 mm of Hg), and a high fraction of inspired oxygen (FiO2 >0.6) as a threshold for intubation while on CPAP. CONCLUSION Not all preterm infants need surfactant treatment, and non-invasive respiratory support is a safe and effective approach.
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Affiliation(s)
- Narayan Prabhu Iyer
- Department of Pediatrics, Division of Neonatology, Case Western Reserve University School of Medicine, MetroHealth Medical Center, Cleveland, Ohio, 44109, USA
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Szyld E, Aguilar A, Musante GA, Vain N, Prudent L, Fabres J, Carlo WA. Comparison of devices for newborn ventilation in the delivery room. J Pediatr 2014; 165:234-239.e3. [PMID: 24690329 DOI: 10.1016/j.jpeds.2014.02.035] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 02/03/2014] [Accepted: 02/18/2014] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To evaluate the effectiveness and safety of a T-piece resuscitator compared with a self-inflating bag for providing mask ventilation to newborns at birth. STUDY DESIGN Newborns at ≥26 weeks gestational age receiving positive-pressure ventilation at birth were included in this multicenter cluster-randomized 2-period crossover trial. Positive-pressure ventilation was provided with either a self-inflating bag (self-inflating bag group) with or without a positive end-expiratory pressure valve or a T-piece with a positive end-expiratory pressure valve (T-piece group). Delivery room management followed American Academy of Pediatrics and International Liaison Committee on Resuscitation guidelines. The primary outcome was the proportion of newborns with heart rate (HR)≥100 bpm at 2 minutes after birth. RESULTS A total of 1027 newborns were included. There was no statistically significant difference in the incidence of HR≥100 bpm at 2 minutes after birth between the T-piece and self-inflating bag groups: 94% (479 of 511) and 90% (466 of 516), respectively (OR, 0.65; 95% CI, 0.41-1.05; P=.08). A total of 86 newborns (17%) in the T-piece group and 134 newborns (26%) in the self-inflating bag group were intubated in the delivery room (OR, 0.58; 95% CI, 0.4-0.8; P=.002). The mean±SD maximum positive inspiratory pressure was 26±2 cm H2O in the T-piece group vs 28±5 cm H2O in the self-inflating bag group (P<.001). Air leaks, use of drugs/chest compressions, mortality, and days on mechanical ventilation did not differ significantly between groups. CONCLUSION There was no difference between the T-piece resuscitator and a self-inflating bag in achieving an HR of ≥100 bpm at 2 minutes in newborns≥26 weeks gestational age resuscitated at birth. However, use of the T-piece decreased the intubation rate and the maximum pressures applied.
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Affiliation(s)
- Edgardo Szyld
- Research Department, FUNDASAMIN, Fundación para la Salud Materno Infantil, Buenos Aires, Argentina.
| | - Adriana Aguilar
- Research Department, FUNDASAMIN, Fundación para la Salud Materno Infantil, Buenos Aires, Argentina; Masters Program in Clinical Trials, Universidad Abierta Interamericana, Buenos Aires, Argentina
| | - Gabriel A Musante
- Research Department, FUNDASAMIN, Fundación para la Salud Materno Infantil, Buenos Aires, Argentina; Department of Pediatrics, Facultad de Ciencias Biomédicas, Universidad Austral, Buenos Aires, Argentina
| | - Nestor Vain
- Research Department, FUNDASAMIN, Fundación para la Salud Materno Infantil, Buenos Aires, Argentina
| | - Luis Prudent
- Research Department, FUNDASAMIN, Fundación para la Salud Materno Infantil, Buenos Aires, Argentina
| | - Jorge Fabres
- Division of Pediatrics, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Waldemar A Carlo
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL
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Prakash YS. Airway smooth muscle in airway reactivity and remodeling: what have we learned? Am J Physiol Lung Cell Mol Physiol 2013; 305:L912-33. [PMID: 24142517 PMCID: PMC3882535 DOI: 10.1152/ajplung.00259.2013] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/12/2013] [Indexed: 12/12/2022] Open
Abstract
It is now established that airway smooth muscle (ASM) has roles in determining airway structure and function, well beyond that as the major contractile element. Indeed, changes in ASM function are central to the manifestation of allergic, inflammatory, and fibrotic airway diseases in both children and adults, as well as to airway responses to local and environmental exposures. Emerging evidence points to novel signaling mechanisms within ASM cells of different species that serve to control diverse features, including 1) [Ca(2+)]i contractility and relaxation, 2) cell proliferation and apoptosis, 3) production and modulation of extracellular components, and 4) release of pro- vs. anti-inflammatory mediators and factors that regulate immunity as well as the function of other airway cell types, such as epithelium, fibroblasts, and nerves. These diverse effects of ASM "activity" result in modulation of bronchoconstriction vs. bronchodilation relevant to airway hyperresponsiveness, airway thickening, and fibrosis that influence compliance. This perspective highlights recent discoveries that reveal the central role of ASM in this regard and helps set the stage for future research toward understanding the pathways regulating ASM and, in turn, the influence of ASM on airway structure and function. Such exploration is key to development of novel therapeutic strategies that influence the pathophysiology of diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis.
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Affiliation(s)
- Y S Prakash
- Dept. of Anesthesiology, Mayo Clinic, 4-184 W Jos SMH, 200 First St. SW, Rochester, MN 55905.
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Madurga A, Mizíková I, Ruiz-Camp J, Morty RE. Recent advances in late lung development and the pathogenesis of bronchopulmonary dysplasia. Am J Physiol Lung Cell Mol Physiol 2013; 305:L893-905. [PMID: 24213917 DOI: 10.1152/ajplung.00267.2013] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
In contrast to early lung development, a process exemplified by the branching of the developing airways, the later development of the immature lung remains very poorly understood. A key event in late lung development is secondary septation, in which secondary septa arise from primary septa, creating a greater number of alveoli of a smaller size, which dramatically expands the surface area over which gas exchange can take place. Secondary septation, together with architectural changes to the vascular structure of the lung that minimize the distance between the inspired air and the blood, are the objectives of late lung development. The process of late lung development is disturbed in bronchopulmonary dysplasia (BPD), a disease of prematurely born infants in which the structural development of the alveoli is blunted as a consequence of inflammation, volutrauma, and oxygen toxicity. This review aims to highlight notable recent developments in our understanding of late lung development and the pathogenesis of BPD.
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Affiliation(s)
- Alicia Madurga
- Dept. of Lung Development and Remodelling, Max Planck Institute for Heart and Lung Research, Parkstrasse 1, D-61231 Bad Nauheim, Germany.
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Hillman NH, Kemp MW, Noble PB, Kallapur SG, Jobe AH. Sustained inflation at birth did not protect preterm fetal sheep from lung injury. Am J Physiol Lung Cell Mol Physiol 2013; 305:L446-53. [PMID: 23873843 DOI: 10.1152/ajplung.00162.2013] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sustained lung inflations (SI) at birth may recruit functional residual capacity (FRC). Clinically, SI increase oxygenation and decrease need for intubation in preterm infants. We tested whether a SI to recruit FRC would decrease lung injury from subsequent ventilation of fetal, preterm lambs. The preterm fetus (128±1 day gestation) was exteriorized from the uterus, a tracheostomy was performed, and fetal lung fluid was removed. While maintaining placental circulation, fetuses were randomized to one of four 15-min interventions: 1) positive end-expiratory pressure (PEEP) 8 cmH2O (n=4), 2) 20 s SI to 50 cmH2O then PEEP 8 cmH2O (n=10), 3) mechanical ventilation at tidal volume (VT) 7 ml/kg (n=13), or 4) 20 s SI then ventilation at VT 7 ml/kg (n=13). Lambs were ventilated with 95% N2/5% CO2 and PEEP 8 cmH2O. Volume recruitment was measured during SI, and fetal tissues were collected after an additional 30 min on placental support. SI achieved a mean FRC recruitment of 15 ml/kg (range 8-27). Fifty percent of final FRC was achieved by 2 s, 65% by 5 s, and 90% by 15 s, demonstrating prolonged SI times are needed to recruit FRC. SI alone released acute-phase proteins into the fetal lung fluid and increased mRNA expression of proinflammatory cytokines and acute-phase response genes in the lung. Mechanical ventilation further increased all markers of lung injury. SI before ventilation, regardless of the volume of FRC recruited, did not alter the acute-phase and proinflammatory responses to mechanical ventilation at birth.
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Affiliation(s)
- Noah H Hillman
- Saint Louis Univ., Cardinal Glennon-Neonatology, 1100 South Grand, Saint Louis, MO 63104.
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Vuckovic A, Herber-Jonat S, Flemmer AW, Roubliova XI, Jani JC. Alveolarization genes modulated by fetal tracheal occlusion in the rabbit model for congenital diaphragmatic hernia: a randomized study. PLoS One 2013; 8:e69210. [PMID: 23840910 PMCID: PMC3698086 DOI: 10.1371/journal.pone.0069210] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 06/08/2013] [Indexed: 12/12/2022] Open
Abstract
Background The mechanisms by which tracheal occlusion (TO) improves alveolarization in congenital diaphragmatic hernia (CDH) are incompletely understood. Therefore transcriptional and histological effects of TO on alveolarization were studied in the rabbit model for CDH. The question of the best normalization strategy for gene expression analysis was also addressed. Methods Fetal rabbits were randomized for CDH or sham operation on gestational day 23/31 and for TO or sham operation on day 28/31 resulting in four study groups. Untouched littermates were added. At term and before lung harvest, fetuses were subjected to mechanical ventilation or not. Quantitative real-time PCR was performed on lungs from 4–5 fetuses of each group with and without previous ventilation. Stability of ten housekeeping genes (HKGs) and optimal number of HKGs for normalization were determined, followed by assessment of HKG expression levels. Expression levels of eleven target genes were studied in ventilated lungs, including genes regulating elastogenesis, cell-environment interactions, and thinning of alveolar walls. Elastic staining, immunohistochemistry and Western blotting completed gene analysis. Results Regarding HKG expression, TO increased β-actin and β-subunit of ATP synthase. Mechanical ventilation increased β-actin and β2-microglobulin. Flavoprotein subunit of succinate dehydrogenase and DNA topoisomerase were the most stable HKGs. CDH lungs showed disorganized elastin deposition with lower levels for tropoelastin, fibulin-5, tenascin-C, and α6-integrin. After TO, CDH lungs displayed a normal pattern of elastin distribution with increased levels for tropoelastin, fibulin-5, tenascin-C, α6-integrin, ß1-integrin, lysyl oxidase, and drebrin. TO increased transcription and immunoreactivity of tissue inhibitor of metalloproteinase-1. Conclusions Experimental TO might improve alveolarization through the mechanoregulation of crucial genes for late lung development. However part of the transcriptional changes involved genes that were not affected in CDH, raising the question of TO-induced disturbances of alveolar remodeling. Attention should also be paid to selection of HKGs for studies on mechanotransduction-mediated gene expressions.
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Affiliation(s)
- Aline Vuckovic
- Laboratory of Physiology and Physiopathology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
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Mechanical ventilation injury and repair in extremely and very preterm lungs. PLoS One 2013; 8:e63905. [PMID: 23704953 PMCID: PMC3660361 DOI: 10.1371/journal.pone.0063905] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 04/08/2013] [Indexed: 11/25/2022] Open
Abstract
Background Extremely preterm infants often receive mechanical ventilation (MV), which can contribute to bronchopulmonary dysplasia (BPD). However, the effects of MV alone on the extremely preterm lung and the lung’s capacity for repair are poorly understood. Aim To characterise lung injury induced by MV alone, and mechanisms of injury and repair, in extremely preterm lungs and to compare them with very preterm lungs. Methods Extremely preterm lambs (0.75 of term) were transiently exposed by hysterotomy and underwent 2 h of injurious MV. Lungs were collected 24 h and at 15 d after MV. Immunohistochemistry and morphometry were used to characterise injury and repair processes. qRT-PCR was performed on extremely and very preterm (0.85 of term) lungs 24 h after MV to assess molecular injury and repair responses. Results 24 h after MV at 0.75 of term, lung parenchyma and bronchioles were severely injured; tissue space and myofibroblast density were increased, collagen and elastin fibres were deformed and secondary crest density was reduced. Bronchioles contained debris and their epithelium was injured and thickened. 24 h after MV at 0.75 and 0.85 of term, mRNA expression of potential mediators of lung repair were significantly increased. By 15 days after MV, most lung injury had resolved without treatment. Conclusions Extremely immature lungs, particularly bronchioles, are severely injured by 2 h of MV. In the absence of continued ventilation these injured lungs are capable of repair. At 24 h after MV, genes associated with injurious MV are unaltered, while potential repair genes are activated in both extremely and very preterm lungs.
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Iliodromiti Z, Zygouris D, Sifakis S, Pappa KI, Tsikouras P, Salakos N, Daniilidis A, Siristatidis C, Vrachnis N. Acute lung injury in preterm fetuses and neonates: mechanisms and molecular pathways. J Matern Fetal Neonatal Med 2013; 26:1696-704. [PMID: 23611524 DOI: 10.3109/14767058.2013.798284] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Acute lung injury (ALI) results in high morbidity and mortality among preterm neonates and efforts have therefore been devoted to both antenatal and postnatal prevention of the disease. ALI is the result of an inflammatory response which is triggered by a variety of different mechanisms. It mostly affects the fetal lung and, in particular, causes damage to the integrity of the lung's alveolar-capillary unit while weakening its cellular linings. Chemotactic activity and inflammatory products, such as proinflammatory cytokines TNF-α, IL-1, IL-6, IL-11, VEGF,TGF-α and TGF-β, provoke serious damage to the capillary endothelium and the alveolar epithelium, resulting in hyaline membrane formation and leakage of protein-rich edema fluid into the alveoli. Chorioamnionitis plays a major part in triggering fetal lung inflammation, while mechanical ventilation, the application of which is frequently necessary in preterm neonates, also causes ALI by inducing proinflammatory cytokines. Many different ventilation-strategies have been developed in order to reduce potential lung injury. Furthermore, tissue injury may occur as a result of injurious oxygen by-products (Reactive Oxygen Species, ROS), secondary to hyperoxia. Knowledge of the inflammatory pathways that connect intra-amniotic inflammation and ALI can lead to the formulation of novel interventional procedures. Future research should concentrate on the pathophysiology of ALI in preterm neonates and οn possible pharmaceutical interventions targeting prevention and/or resolution of ALI.
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Affiliation(s)
- Zoe Iliodromiti
- 2nd Department of Obstetrics and Gynecology, University of Athens Medical School, Aretaieio Hospital , Athens , Greece
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Bibliography. Current world literature. Neonatology and perinatology. Curr Opin Pediatr 2013; 25:275-81. [PMID: 23481475 DOI: 10.1097/mop.0b013e32835f58ca] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hillman N, Kallapur SG, Jobe A. Physiology of transition from intrauterine to extrauterine life. Clin Perinatol 2012; 39:769-83. [PMID: 23164177 PMCID: PMC3504352 DOI: 10.1016/j.clp.2012.09.009] [Citation(s) in RCA: 239] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The transition from fetus to newborn is the most complex adaptation that occurs in human experience. Lung adaptation requires coordinated clearance of fetal lung fluid, surfactant secretion, and onset of consistent breathing. The cardiovascular response requires striking changes in blood flow, pressures, and pulmonary vasodilation. Energy metabolism and thermoregulation must be quickly controlled. The primary mediators that prepare the fetus for birth and support the multiorgan transition are cortisol and catecholamine. Abnormalities in adaptation are frequently found following preterm birth or cesarean delivery at term, and many of these infants need delivery room resuscitation to assist in this transition.
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Abstract
BACKGROUND Preterm infants often receive mechanical ventilation and oxygen at birth. Exposure to large tidal volumes (V(T)s) at birth causes lung inflammation, and oxygen may amplify the injury. We hypothesized that normal V(T) ventilation at birth causes lung injury that is exacerbated by 95% oxygen. METHODS The head and chest of anesthetized preterm fetal sheep (129 ± 1 d gestation) were surgically exteriorized while maintaining the placental circulation. Fetuses were randomized to four groups with either V(T) ventilation to 6 ml/kg or continuous positive airway pressure of 5 cm H2O, and either 95%O2/5%CO2 or 95%N2/5%CO2. Age-matched fetuses were used as controls. After a 15-min intervention, the fetal lamb was returned to the uterus for 1 h 45 min. RESULTS In ventilated lambs, V(T) was 6.2 ± 0.4 ml/kg at 15 min. Ventilation increased proinflammatory cytokines as compared with controls and lambs on continuous positive airway pressure, with recruitment of primarily monocytes to bronchoalveolar lavage fluid. Early response protein 1 was activated around the bronchioles in V(T)-ventilated animals. The 15-min oxygen exposure did not change inflammatory mediators or other markers of lung and oxidative stress. CONCLUSION A V(T) of 6-7 ml/kg at birth increased early markers of injury and lung inflammation. Brief exposure to 95% oxygen did not alter lung inflammation.
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Polglase GR, Miller SL, Barton SK, Baburamani AA, Wong FY, Aridas JDS, Gill AW, Moss TJM, Tolcos M, Kluckow M, Hooper SB. Initiation of resuscitation with high tidal volumes causes cerebral hemodynamic disturbance, brain inflammation and injury in preterm lambs. PLoS One 2012; 7:e39535. [PMID: 22761816 PMCID: PMC3382197 DOI: 10.1371/journal.pone.0039535] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/23/2012] [Indexed: 11/21/2022] Open
Abstract
AIMS Preterm infants can be inadvertently exposed to high tidal volumes (V(T)) in the delivery room, causing lung inflammation and injury, but little is known about their effects on the brain. The aim of this study was to compare an initial 15 min of high V(T) resuscitation strategy to a less injurious resuscitation strategy on cerebral haemodynamics, inflammation and injury. METHODS Preterm lambs at 126 d gestation were surgically instrumented prior to receiving resuscitation with either: 1) High V(T) targeting 10-12 mL/kg for the first 15 min (n = 6) or 2) a protective resuscitation strategy (Prot V(T)), consisting of prophylactic surfactant, a 20 s sustained inflation and a lower initial V(T) (7 mL/kg; n = 6). Both groups were subsequently ventilated with a V(T) 7 mL/kg. Blood gases, arterial pressures and carotid blood flows were recorded. Cerebral blood volume and oxygenation were assessed using near infrared spectroscopy. The brain was collected for biochemical and histologic assessment of inflammation, injury, vascular extravasation, hemorrhage and oxidative injury. Unventilated controls (UVC; n = 6) were used for comparison. RESULTS High V(T) lambs had worse oxygenation and required greater ventilatory support than Prot V(T) lambs. High V(T) resulted in cerebral haemodynamic instability during the initial 15 min, adverse cerebral tissue oxygenation index and cerebral vasoparalysis. While both resuscitation strategies increased lung and brain inflammation and oxidative stress, High V(T) resuscitation significantly amplified the effect (p = 0.014 and p<0.001). Vascular extravasation was evident in the brains of 60% of High V(T) lambs, but not in UVC or Prot V(T) lambs. CONCLUSION High V(T) resulted in greater cerebral haemodynamic instability, increased brain inflammation, oxidative stress and vascular extravasation than a Prot V(T) strategy. The initiation of resuscitation targeting Prot V(T) may reduce the severity of brain injury in preterm neonates.
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Affiliation(s)
- Graeme R Polglase
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia.
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