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Gallup JA, Ndakor SM, Pezzano C, Pinheiro JMB. Randomized Trial of Surfactant Therapy via Laryngeal Mask Airway Versus Brief Tracheal Intubation in Neonates Born Preterm. J Pediatr 2023; 254:17-24.e2. [PMID: 36241051 DOI: 10.1016/j.jpeds.2022.10.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/30/2022] [Accepted: 10/07/2022] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To evaluate the possible noninferiority of surfactant administration via laryngeal mask airway (LMA) vs endotracheal tube (ETT) in avoiding the requirement for mechanical ventilation in preterm neonates with respiratory distress syndrome (RDS). STUDY DESIGN This was a randomized controlled trial including infants born at 27 to 36 weeks of gestation, >800 g, diagnosed with RDS and receiving fraction of inspired oxygen 0.30-0.60 via noninvasive respiratory support. Infants were randomized to surfactant via LMA (with atropine premedication) or ETT (InSuRE approach with atropine and remifentanil premedication). Primary outcome was failure of surfactant treatment to prevent the need for mechanical ventilation. RESULTS Patients were randomized, 51 to LMA and 42 to the ETT group. Both groups had similar baseline characteristics, with birth weights ranging from 810 to 3560 g. Failure rate was 29% in the ETT group and 20% in the LMA group (P = .311). This difference was due to early failures (within 1 hour), with 12.5% in the ETT group and 2% in the LMA group (P = .044). Surfactant therapy via LMA was non-inferior to administration via ETT; failure risk difference -9.0% (CI -∞ to 5.7%). Efficacy in decreasing fraction of inspired oxygen, number of surfactant doses administered, time to wean off all respiratory support, rates of adverse events, and outcomes including pneumothorax and BPD diagnosis did not differ between groups. CONCLUSIONS Surfactant therapy via LMA was noninferior to administration via ETT and it decreased early failures, possibly by avoiding adverse effects of premedication, laryngoscopy, and intubation. These characteristics make LMA a desirable conduit for surfactant administration. TRIAL REGISTRATION ClinicalTrials.gov, NCT02164734.
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Affiliation(s)
- Jacqueline A Gallup
- Department of Pediatrics, Albany Medical College, Albany, NY; Faxton-St Luke's Healthcare, Utica, NY
| | - Sussan Mbi Ndakor
- Department of Pediatrics, Albany Medical College, Albany, NY; UnityPoint Health, Waterloo, IA
| | - Chad Pezzano
- Department of Pediatrics, Albany Medical College, Albany, NY; Cardiorespiratory Services Department, Albany Medical Center, Albany, NY
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Guo X, Luo S, Amidani D, Rivetti C, Pieraccini G, Pioselli B, Catinella S, Murgia X, Salomone F, Xu Y, Dong Y, Sun B. In vitro characterization and in vivo comparison of the pulmonary outcomes of Poractant alfa and Calsurf in ventilated preterm rabbits. PLoS One 2020; 15:e0230229. [PMID: 32168331 PMCID: PMC7069639 DOI: 10.1371/journal.pone.0230229] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 02/12/2020] [Indexed: 11/18/2022] Open
Abstract
Poractant alfa and Calsurf are two natural surfactants widely used in China for the treatment of neonatal respiratory distress syndrome, which are extracted from porcine and calf lungs, respectively. The purpose of this experimental study was to compare their in vitro characteristics and in vivo effects in the improvement of pulmonary function and protection of lung injury. The biophysical properties, ultrastructure, and lipid composition of both surfactant preparations were respectively analysed in vitro by means of Langmuir-Blodgett trough (LBT), atomic force microscopy (AFM), and liquid-chromatography mass-spectrometry (LC-MS). Then, as core pharmacological activity, both head-to-head (100 and 200 mg/kg for both surfactants) and licensed dose comparisons (70 mg/kg Calsurf vs. 200 mg/kg Poractant alfa) between the two surfactants were conducted as prophylaxis in preterm rabbits with primary surfactant deficiency, assessing survival time and rate and dynamic compliance of the respiratory system (Cdyn). Intrapulmonary surfactant pools, morphometric volume density as alveolar expansion (Vv), and lung injury scores were determined post mortem. AFM and LC-MS analysis revealed qualitative differences in the ultrastructure as well as in the lipid composition of both preparations. Calsurf showed a longer plateau region of the LBT isotherm and lower film compressibility. In vivo, both surfactant preparations improved Cdyn at any dose, although maximum benefits in terms of Vv and intrapulmonary surfactant pools were seen with the 200 mg/kg dose in both surfactants. The group of animals treated with 200 mg/kg of Poractant alfa showed a prolonged survival time and rate compared to untreated but ventilated controls, and significantly ameliorated lung injury compared to Calsurf at any dose, including 200 mg/kg. The overall outcomes suggest the pulmonary effects to be dose dependent for both preparations. The group of animals treated with 200 mg/kg of Poractant alfa showed a significant reduction of mortality. Compared to Calsurf, Poractant alfa exerted better effects if licensed doses were compared, which requires further investigation.
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Affiliation(s)
- Xiaojing Guo
- Departments of Pediatrics and Neonatology, Children’s Hospital of Fudan University, Shanghai, China
| | - Siwei Luo
- Departments of Pediatrics and Neonatology, Children’s Hospital of Fudan University, Shanghai, China
| | - Davide Amidani
- Department of Research and Development, Chiesi Farmaceutici, Parma, Italy
| | - Claudio Rivetti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Giuseppe Pieraccini
- CISM Mass Spectrometry Centre, Department of Health Sciences, University of Florence, Firenze, Italy
| | - Barbara Pioselli
- Department of Research and Development, Chiesi Farmaceutici, Parma, Italy
| | - Silvia Catinella
- Department of Research and Development, Chiesi Farmaceutici, Parma, Italy
| | - Xabi Murgia
- Department of Drug Delivery, Helmholtz Institute for Pharmaceutical Research, Saarbrücken, Saarland, Germany
| | - Fabrizio Salomone
- Department of Research and Development, Chiesi Farmaceutici, Parma, Italy
| | - Yaling Xu
- Departments of Pediatrics and Neonatology, Children’s Hospital of Fudan University, Shanghai, China
| | - Ying Dong
- Departments of Pediatrics and Neonatology, Children’s Hospital of Fudan University, Shanghai, China
| | - Bo Sun
- Departments of Pediatrics and Neonatology, Children’s Hospital of Fudan University, Shanghai, China
- * E-mail: ,
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Liszewski MC, Ciet P, Lee EY. Lung and Pleura. PEDIATRIC BODY MRI 2020. [PMCID: PMC7245516 DOI: 10.1007/978-3-030-31989-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Suppression of pulmonary group B streptococcal proliferation and translocation by surfactants in ventilated near-term newborn rabbits. Pediatr Res 2019; 86:208-215. [PMID: 31086290 DOI: 10.1038/s41390-019-0421-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 04/18/2019] [Accepted: 04/18/2019] [Indexed: 02/01/2023]
Abstract
BACKGROUND The pathogenesis of neonatal group B Streptococcus (GBS) lung infection may be associated with surfactant dysfunction or deficiency. This study aimed to investigate the efficacy of surfactants on early postnatal GBS infection in ventilated newborn rabbit lungs. METHODS A near-term newborn rabbit model was established by intratracheal GBS instillation immediately at birth, followed by mechanical ventilation. At postnatal 1 h, a porcine surfactant was given intratracheally at 100 or 200 mg/kg. After 6 h, animals were euthanized, and lung and blood samples were collected for bacterial counting. Lung histopathology and messenger RNA (mRNA) expression of inflammatory mediators, surfactant proteins, and growth factors in lung tissue were assessed. RESULTS The surfactants significantly suppressed (by >50%) pulmonary bacterial proliferation and systemic translocation, alleviated lung inflammatory injury, and improved alveolar expansion by morphometry, in favor of high-dose surfactants. Though the survival rate and lung mechanics were not improved, the surfactants significantly suppressed mRNA expression of proinflammatory mediators, while that for surfactant proteins and growth factors was differentially expressed, compared to the control and GBS infection groups. CONCLUSION Exogenous surfactants may provide a therapeutic alternative for neonatal lung infection by suppressing pulmonary GBS proliferation and translocation into systemic circulation, alleviating inflammatory injury and regulating growth factor expression.
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McPherson C, Wambach JA. Prevention and Treatment of Respiratory Distress Syndrome in Preterm Neonates. Neonatal Netw 2018; 37:169-177. [PMID: 29789058 DOI: 10.1891/0730-0832.37.3.169] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Respiratory distress syndrome (RDS) impacts a high proportion of preterm neonates, resulting in significant morbidity and mortality. Advances in pharmacotherapy, specifically antenatal corticosteroids and postnatal surfactant therapy, have significantly reduced the incidence and impact of neonatal RDS. Antenatal corticosteroids accelerate fetal lung maturation by increasing the activity of enzymes responsible for surfactant biosynthesis, resulting in improved lung compliance. Maternal antenatal corticosteroid treatment has improved survival of preterm neonates and lowered the incidence of brain injury. After birth, exogenous surfactant administration improves lung compliance and oxygenation, resulting in reductions in the incidence of pneumothorax and of death. Future research will identify the optimal surfactant product, timing of the initial dose, and mode of delivery.
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Rimensberger PC. Surfactant. PEDIATRIC AND NEONATAL MECHANICAL VENTILATION 2015. [PMCID: PMC7175631 DOI: 10.1007/978-3-642-01219-8_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Exogenous pulmonary surfactant, widely used in neonatal care, is one of the best-studied treatments in neonatology, and its introduction in the 1990s led to a significant improvement in neonatal outcomes in preterm infants, including a decrease in mortality. This chapter provides an overview of surfactant composition and function in health and disease and summarizes the evidence for its clinical use.
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Affiliation(s)
- Peter C. Rimensberger
- Service of Neonatology and Pediatric Intensive Care, Department of Pediatrics, University Hospital of Geneva, Geneve, Switzerland
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Niemarkt HJ, Kuypers E, Jellema R, Ophelders D, Hütten M, Nikiforou M, Kribs A, Kramer BW. Effects of less-invasive surfactant administration on oxygenation, pulmonary surfactant distribution, and lung compliance in spontaneously breathing preterm lambs. Pediatr Res 2014; 76:166-70. [PMID: 24796373 DOI: 10.1038/pr.2014.66] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 02/03/2014] [Indexed: 11/09/2022]
Abstract
BACKGROUND A new technique was proposed to administer surfactant to spontaneous breathing preterm infants by placing a thin catheter through the vocal cords. This technique was not studied with respect to oxygenation, gas exchange, surfactant distribution, and lung mechanics. We tested the technique of less-invasive surfactant administration (LISA) in a spontaneous breathing preterm lamb model. METHODS Preterm lambs (n = 12) of 133-134 d gestational age were randomized to the following three groups: (i) continuous positive airway pressure (CPAP) only, (ii) CPAP + LISA, and (iii) intubation and mechanical ventilation with surfactant administration. Surfactant was labeled with samarium oxide. During the next 180 min, blood gas analyses were performed. Postmortem, lungs were removed and surfactant distribution was assessed, and pressure-volume curves were performed. RESULTS Pao2 in the LISA-treated lambs was significantly higher than in the lambs that exclusively received CPAP. Moreover, Pao2 values were similar between the LISA-treated and the intubated lambs. Overall, surfactant deposition was less in the LISA lambs, with significantly less surfactant distributed to the right upper lobe. Lung compliance was better in the intubated lambs compared with the LISA-treated lambs, although this did not reach significance. CONCLUSION LISA improved oxygenation, similar to conventional surfactant application techniques, despite lower surfactant deposition and lung compliance.
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Affiliation(s)
- Hendrik J Niemarkt
- Department of Pediatrics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Elke Kuypers
- Department of Pediatrics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Reint Jellema
- Department of Pediatrics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Daan Ophelders
- Department of Pediatrics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Matthias Hütten
- 1] Department of Pediatrics, Maastricht University Medical Center, Maastricht, The Netherlands [2] Section of Neonatology, Department of Pediatric and Adolescent Medicine, University Hospital RWTH Aachen, Aachen, Germany
| | - Maria Nikiforou
- Department of Pediatrics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Angela Kribs
- Neonatology, Department of Pediatric and Adolescent Medicine, University Hospital, University Köln, Köln, Germany
| | - Boris W Kramer
- Department of Pediatrics, Maastricht University Medical Center, Maastricht, The Netherlands
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Rojas-Reyes MX, Morley CJ, Soll R. Prophylactic versus selective use of surfactant in preventing morbidity and mortality in preterm infants. Cochrane Database Syst Rev 2012:CD000510. [PMID: 22419276 DOI: 10.1002/14651858.cd000510.pub2] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Surfactant therapy is effective in improving the outcome of very preterm infants. Trials have studied a wide variety of surfactant preparations used either to prevent or treat respiratory distress syndrome (RDS). In animal models, prophylactic surfactant leads to more homogeneous distribution and less evidence of lung damage. However, administration requires intubation and treatment of infants who will not go on to develop RDS. This is of particular concern with the advent of improved approaches to providing continuous distending pressure, particularly in the form of nasal continuous positive airway pressure (CPAP). OBJECTIVES To compare the effect of prophylactic surfactant administration to surfactant treatment of established RDS in very preterm infants at risk of RDS. SEARCH METHODS We updated the search of the Cochrane Central Register of Controlled Trials (The Cochrane Library), MEDLINE, EMBASE, CINAHL, and clinical trials.gov register in December 13, 2011. SELECTION CRITERIA Randomized and quasi-randomized controlled trials that compared the effects of prophylactic surfactant administration to surfactant treatment of established RDS in preterm infants at risk of RDS. DATA COLLECTION AND ANALYSIS Data regarding clinical outcomes were extracted from the reports of the clinical trials by the reviewers. Data analysis was done in accordance with the standards of the Cochrane Neonatal Review Group. MAIN RESULTS Eleven studies were identified that met inclusion criteria [nine without routine application of continuous positive air way pressure (CPAP) in the selective treatment group; two with routine application of CPAP in the selective treatment group]The meta-analysis of studies conducted prior to the routine application of CPAP demonstrated a decrease in the risk of air leak and neonatal mortality associated with prophylactic administration of surfactant. However, the analyses of studies that allowed for routine stabilization on CPAP demonstrated a decrease in the risk of chronic lung disease or death in infants stabilized on CPAP. When all studies were evaluated together, the benefits of prophylactic surfactant could no longer be demonstrated. AUTHORS' CONCLUSIONS Although the early trials of prophylactic surfactant administration to infants judged to be at risk of developing RDS compared to selective use of surfactant in infants with established RDS demonstrated a decreased risk of air leak and mortality, recent large trials that reflect current practice (including greater utilization of maternal steroids and routine post delivery stabilization on CPAP) do not support these differences and demonstrate less risk of chronic lung disease or death when using early stabilization on CPAP with selective surfactant administration to infants requiring intubation.
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Affiliation(s)
- Maria Ximena Rojas-Reyes
- Department of Clinical Epidemiology and Biostatistics, Faculty of Medicine, Pontificia Universidad Javeriana, Bogota, Colombia
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Hillman NH, Nitsos I, Berry C, Pillow JJ, Kallapur SG, Jobe AH. Positive end-expiratory pressure and surfactant decrease lung injury during initiation of ventilation in fetal sheep. Am J Physiol Lung Cell Mol Physiol 2011; 301:L712-20. [PMID: 21856815 DOI: 10.1152/ajplung.00157.2011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The initiation of ventilation in preterm, surfactant-deficient sheep without positive end-expiratory pressure (PEEP) causes airway injury and lung inflammation. We hypothesized that PEEP and surfactant treatment would decrease the lung injury from initiation of ventilation with high tidal volumes. Fetal sheep at 128-day gestational age were randomized to ventilation with: 1) no PEEP, no surfactant; 2) 8-cmH(2)O PEEP, no surfactant; 3) no PEEP + surfactant; 4) 8-cmH(2)O PEEP + surfactant; or 5) control (2-cmH(2)O continuous positive airway pressure) (n = 6-7/group). After maternal anesthesia and hysterotomy, the head and chest were exteriorized, and the fetus was intubated. While maintaining placental circulation, the fetus was ventilated for 15 min with a tidal volume escalating to 15 ml/kg using heated, humidified, 100% nitrogen. The fetus then was returned to the uterus, and tissue was collected after 30 min for evaluation of early markers of lung injury. Lambs receiving both surfactant and PEEP had increased dynamic compliance, increased static lung volumes, and decreased total protein and heat shock proteins 70 and 60 in bronchoalveolar lavage fluid compared with other groups. Ventilation, independent of PEEP or surfactant, increased mRNA expression of acute phase response genes and proinflammatory cytokine mRNA in the lung tissue compared with controls. PEEP decreased mRNA for cytokines (2-fold) compared with groups receiving no PEEP. Surfactant administration further decreased some cytokine mRNAs and changed the distribution of early growth response protein-1 expression. The use of PEEP during initiation of ventilation at birth decreased early mediators of lung injury. Surfactant administration changed the distribution of injury and had a moderate additive protective effect.
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Affiliation(s)
- Noah H Hillman
- Cincinnati Children's Hospital Medical Center, Division of Pulmonary Biology, 3333 Burnet Ave., Cincinnati, OH 45229-3039, USA.
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Siew ML, Te Pas AB, Wallace MJ, Kitchen MJ, Islam MS, Lewis RA, Fouras A, Morley CJ, Davis PG, Yagi N, Uesugi K, Hooper SB. Surfactant increases the uniformity of lung aeration at birth in ventilated preterm rabbits. Pediatr Res 2011; 70:50-5. [PMID: 21451432 DOI: 10.1203/pdr.0b013e31821be094] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Surfactant deficiency is a major cause of respiratory failure in newborns. We have investigated the roles of surfactant and positive end-expiratory pressure (PEEP) in the development of a functional residual capacity (FRC) and the distribution of ventilation at birth. Preterm rabbit pups (28 d GA) were delivered and received either saline or surfactant and then ventilated with (3PEEP) or without (0PEEP) 3 cm H2O PEEP (groups: saline/0PEEP, surfactant/0PEEP, saline/3PEEP, surfactant/3PEEP). Lung gas volumes were measured using plethysmography, and the uniformity of ventilation was analyzed using phase contrast (PC) x-ray imaging. Surfactant/0PEEP pups had greater FRCs and the lungs were more uniformly ventilated than saline/0PEEP pups; FRC at inflation 19-21 was 2.46 ± 0.52 mL/kg versus 0.91 ± 0.95 mL/kg (p < 0.05). Saline/3PEEP pups developed an FRC of 7.54 ± 1.68 mL/kg at inflation 19-21 (p < 0.05), but the distribution of ventilation was initially nonuniform. Surfactant/3PEEP pups had an FRC of 8.50 ± 0.80 mL/kg (at inflation 19-21), and the distribution of ventilation was more uniform than with saline/3PEEP (p < 0.05). In ventilated preterm newborn rabbits, PEEP has a greater effect on FRC than surfactant, although the two are additive. Surfactant, administered at birth, markedly improved the uniformity of ventilation irrespective of whether PEEP was applied.
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Affiliation(s)
- Melissa L Siew
- Monash Institute of Medical Research, Clayton, Vic 3168, Australia
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Polglase GR, Kluckow M, Gill AW, Allison BJ, Moss TJM, Dalton RGB, Pillow JJ, Andersen CC, Nitsos I, Hooper SB. Cardiopulmonary haemodynamics in lambs during induced capillary leakage immediately after preterm birth. Clin Exp Pharmacol Physiol 2011; 38:222-8. [DOI: 10.1111/j.1440-1681.2011.05489.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ventre K, Haroon M, Davison C. WITHDRAWN. Surfactant therapy for bronchiolitis in critically ill infants. Cochrane Database Syst Rev 2010; 2010:CD005150. [PMID: 20091572 PMCID: PMC10641642 DOI: 10.1002/14651858.cd005150.pub3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Viral bronchiolitis is a common cause of respiratory failure in infants and children, and accounts for a significant portion of intensive care unit (ICU) admissions during seasonal epidemics. Currently there is no evidence to support the use of anything but supportive care for this disease. Surfactant is a potentially promising therapy; alterations in its composition have been described in bronchiolitis, and it may play a role in the host immunity for this disease. OBJECTIVES To assess the efficacy of exogenous surfactant for the treatment of bronchiolitis in mechanically ventilated infants and children. SEARCH STRATEGY We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2006, issue 1) which contains the Acute Respiratory Infections Group's Specialized Register; MEDLINE (1966 to Week 1, February 2006); and EMBASE (1990 to September 2005). SELECTION CRITERIA Randomised controlled trials (RCTs) comparing surfactant with placebo or surfactant with no surfactant in mechanically ventilated infants and children with viral bronchiolitis. DATA COLLECTION AND ANALYSIS Two authors independently extracted data and assessed trial quality. Unpublished data were requested from trial authors when necessary. MAIN RESULTS Three trials containing a total of 79 patients met the inclusion criteria. No mortality or adverse effects associated with surfactant administration were reported in any of these trials. In the three trials, use of surfactant was associated with a decrease in duration of mechanical ventilation by 2.6 days (95% confidence interval (CI) -5.34 to 0.18 days; P value 0.07) and a decrease in ICU length of stay by 3.3 days (95% CI -6.38 to -0.23 days; P value 0.04). In two studies with 59 patients, in which duration of mechanical ventilation in the control groups was more comparable, surfactant was associated with a decrease in ventilator days by 1.21 days (95% CI 0.75 to 1.67 days) and a decrease in ICU stay by 1.81 days (95% CI 1.19 days to 2.42 days). Individually the studies reported some short term benefit of surfactant on pulmonary mechanics and gas exchange. AUTHORS' CONCLUSIONS Available data on surfactant were not sufficient to provide reliable estimates of its effects in mechanically ventilated infants and children with bronchiolitis. Future studies should be adequately powered and will need to address unresolved questions regarding which surfactant preparation may be best suited for the treatment of bronchiolitis, the appropriate dose and administration interval, and how the choice of ventilator strategy may modify its effects.
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Affiliation(s)
- Kathleen Ventre
- Primary Children's Medical CenterDivision of Critical Care Medicine100 N. Medical DriveSalt Lake CityUtahUSA84113
| | - Munib Haroon
- NHS Leicester CityChildrens ServicesBridgepark PlazaBridgepark RoadThurmastonLeicesterUKLE4 8PQ
| | - Caroline Davison
- St George's HospitalDepartment of AnaestheticsTootingLondonUKSW17 0QT
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Hillman NH, Moss TJM, Kallapur SG, Bachurski C, Pillow JJ, Polglase GR, Nitsos I, Kramer BW, Jobe AH. Brief, large tidal volume ventilation initiates lung injury and a systemic response in fetal sheep. Am J Respir Crit Care Med 2007; 176:575-81. [PMID: 17641159 PMCID: PMC1994225 DOI: 10.1164/rccm.200701-051oc] [Citation(s) in RCA: 186] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Premature infants are exposed to potentially injurious ventilation in the delivery room. Assessments of lung injury are confounded by effects of subsequent ventilatory support. OBJECTIVES To evaluate the injury response to a brief period of large tidal volume (Vt) ventilation, simulating neonatal resuscitation in preterm neonates. METHODS Preterm lambs (129 d gestation; term is150 d) were ventilated (Vt = 15 ml/kg, no positive end-expiratory pressure) for 15 minutes to simulate delivery room resuscitation, either with the placental circulation intact (fetal resuscitation [ FR]) or after delivery (neonatal resuscitation [NR]). After the initial 15 minutes, lambs received surfactant and were maintained with either ventilatory support (FR-VS and NR-VS) or placental support (FR-PS) for 2 hours, 45 minutes. A control group received no resuscitation and was maintained with placental support. Samples of bronchoalveolar lavage fluid, lung, and liver were analyzed. MEASUREMENTS AND MAIN RESULTS Inflammatory cells and protein in bronchoalveolar lavage fluid, heat shock protein-70 immunostaining, IL-1beta, IL-6, IL-8, monocyte chemotactic protein-1, serum amyloid A (SAA)-3, Toll-like receptor (TLR)-2, and TLR4 mRNA in the lungs were increased in the FR-PS group compared with control animals. There were further elevations in neutrophils, IL-6, and IL-8 mRNA in the FR-VS and NR-VS groups compared with FR-PS. SAA3, TLR2, and TLR4 mRNA increased in the liver in all resuscitation groups relative to control animals. CONCLUSIONS Ventilation for 15 minutes with a Vt of 15 ml/kg initiates an injurious process in the preterm lung and a hepatic acute-phase response. Subsequent ventilatory support causes further increases in some injury indicators.
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Affiliation(s)
- Noah H Hillman
- Cincinnati Children's Hospital Medical Center, Division of Pulmonary Biology, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA
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van Veenendaal MB, van Kaam AH, Haitsma JJ, Lutter R, Lachmann B. Open lung ventilation preserves the response to delayed surfactant treatment in surfactant-deficient newborn piglets. Crit Care Med 2006; 34:2827-34. [PMID: 17006360 DOI: 10.1097/01.ccm.0000243794.09377.96] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Delayed surfactant treatment (>2 hrs after birth) is less effective than early treatment in conventionally ventilated preterm infants with respiratory distress syndrome. The objective of this study was to evaluate if this time-dependent efficacy of surfactant treatment is also present during open lung ventilation. DESIGN Prospective, randomized controlled animal study. SETTING University-affiliated research laboratory. SUBJECTS Thirty-eight newborn piglets. INTERVENTIONS Following repeated whole-lung lavage, animals were randomly allocated to conventional positive pressure ventilation (PPVCON) using a positive end-expiratory pressure (PEEP) of 5 cm H2O and a tidal volume of 7 mL/kg or open lung positive pressure ventilation (PPVOLV). During PPVOLV, collapsed alveoli were actively recruited and thereafter stabilized with sufficient PEEP. Within each ventilation group, animals received surfactant (25 mg/kg) either after 2 hrs (PPVCON-2 and PPVOLV-2) or after 4 hrs (PPVCON-4 and PPVOLV-4) of ventilation. A control group received surfactant immediately after lung lavage. Following surfactant administration, all animals were conventionally ventilated for an additional 2 hrs. MEASUREMENTS AND MAIN RESULTS Two hours after surfactant treatment, both oxygenation and lung mechanics showed a clear deterioration in the PPVCON-4 group compared with PPVCON-2 and the control group. However, this deterioration of the surfactant response over time was not observed during PPVOLV. Analysis of the bronchoalveolar lavage fluid obtained at the end of the experiment showed that the protein concentration and the conversion of large to small aggregate surfactant was significantly higher in the PPVCON-4 group compared with the PPVCON-2 group while comparable in both PPVOLV groups. In addition, interleukin-8 and myeloperoxidase levels tended to be higher in the PPVCON-4 group compared with the PPVOLV-4 group. CONCLUSIONS In contrast to conventional ventilation, open lung ventilation preserves the response to delayed surfactant treatment in surfactant-deficient newborn piglets. This sustained response is accompanied by an attenuation of secondary lung injury.
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Affiliation(s)
- Mariëtte B van Veenendaal
- Department of Neonatology, Emma Children's Hospital AMC, University of Amsterdam, Amsterdam, The Netherlands
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Abstract
BACKGROUND Viral bronchiolitis is a common cause of respiratory failure in infants and children, and accounts for a significant portion of intensive care unit (ICU) admissions during seasonal epidemics. Currently there is no evidence to support the use of anything but supportive care for this disease. Surfactant is a potentially promising therapy; alterations in its composition have been described in bronchiolitis, and it may play a role in the host immunity for this disease. OBJECTIVES The objective of this review was to assess the efficacy of exogenous surfactant for the treatment of bronchiolitis in mechanically ventilated infants and children. SEARCH STRATEGY We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2006); MEDLINE (1966 to Week 1, February 2006); and EMBASE (1990 to September 2005). We reviewed reference lists of relevant articles and contacted experts in the field. SELECTION CRITERIA Randomised controlled trials (RCTs) comparing surfactant with placebo or surfactant with no surfactant in mechanically ventilated infants and children with viral bronchiolitis. DATA COLLECTION AND ANALYSIS Two authors independently extracted data and assessed trial quality. Unpublished data were requested from trial authors when necessary. MAIN RESULTS Three trials containing a total of 79 patients met the inclusion criteria. No mortality or adverse effects associated with surfactant administration were reported in any of these trials. In the three trials, use of surfactant was associated with a decrease in duration of mechanical ventilation by 2.6 days (95% confidence interval (CI) -5.34 to 0.18 days; P value 0.07) and a decrease in ICU length of stay by 3.3 days (95% CI -6.38 to -0.23 days; P value 0.04). In two studies with 59 patients, in which duration of mechanical ventilation in the control groups was more comparable, surfactant was associated with a decrease in ventilator days by 1.21 days (95% CI 0.75 to 1.67 days) and a decrease in ICU stay by 1.81 days (95% CI 1.19 days to 2.42 days). Individually the studies reported some short term benefit of surfactant on pulmonary mechanics and gas exchange. AUTHORS' CONCLUSIONS Available data on surfactant were not sufficient to provide reliable estimates of its effects in mechanically ventilated infants and children with bronchiolitis. Future studies should be adequately powered and will need to address unresolved questions regarding which surfactant preparation may be best suited for the treatment of bronchiolitis, the appropriate dose and administration interval, and how the choice of ventilator strategy may modify its effects.
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Affiliation(s)
- K Ventre
- Primary Children's Medical Center, Division of Critical Care Medicine, 100 N. Medical Drive, Salt Lake City, Utah 84113, USA.
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Wang X, Sun Z, Qian L, Guo C, Yu W, Wang W, Lu KW, Taeusch HW, Sun B. Effects of Hyaluronan-Fortified Surfactant in Ventilated Premature Piglets with Respiratory Distress. Neonatology 2006; 89:15-24. [PMID: 16155382 DOI: 10.1159/000088194] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Accepted: 04/18/2005] [Indexed: 11/19/2022]
Abstract
We hypothesized that enriching surfactant with hyaluronan would restore lung function when tested in a premature animal model. Newborn piglets (85% gestation, term 112-114 days) were delivered by cesarean section, subjected to mechanical ventilation (tidal volume 6- 8 ml/kg) and randomly assigned to treatment with 50 or 100 mg/kg Curosurf (C50 and C100), 50 or 100 mg/kg Curosurf mixed with 2.5% HA (w/w, CH50 and CH100). A ventilated and not treated group (Cont) and a not treated and not ventilated group (Non) were included as controls. Six hours after treatment the lungs were removed and biochemical, biophysical, cytological and histological analyses were carried out. The CH100, CH50, C100 and C50 groups had variable but significantly improved alveolar phospholipid content, minimal surface tension, alveolar aeration and wet/dry lung weight ratios, but little histological evidence of lung injury. CH100, CH50 and C100 groups had the best effects in terms of oxygenation, lung compliance and histology and evidence of decreased inflammation (IL-8 and TNF-alpha mRNA expression). We conclude that HA added to 50 mg/kg Curosurf or use of 100 mg/kg Curosurf with or without HA provides the best effects in terms of lung function and reduction of inflammation.
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Affiliation(s)
- Xiaoning Wang
- Laboratory of Pediatric Respiratory and Intensive Care Medicine, Children's Hospital of Fudan University, Shanghai, PR China
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18
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Bohlin K, Bouhafs RKL, Jarstrand C, Curstedt T, Blennow M, Robertson B. Spontaneous breathing or mechanical ventilation alters lung compliance and tissue association of exogenous surfactant in preterm newborn rabbits. Pediatr Res 2005; 57:624-30. [PMID: 15718361 DOI: 10.1203/01.pdr.0000156502.84909.bc] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In preterm infants with respiratory distress syndrome, surfactant administration followed by immediate extubation to spontaneous breathing with nasal continuous positive airway pressure reduces the need for mechanical ventilation. With this treatment approach, repeated doses of surfactant are rarely indicated. We used a rabbit model to test the hypothesis that exogenous surfactant therapy followed by spontaneous breathing results in a more sustained initial treatment response compared with treatment followed by mechanical ventilation. Preterm rabbits (gestational age 28.5 d) were treated with pharyngeal deposition of 200 mg/kg radiolabeled surfactant (14C-Curosurf) and randomized to 4 h of spontaneous breathing or mechanical ventilation or to a control group, killed immediately after surfactant administration. With pharyngeal deposition, 46 +/- 10% (mean +/- SEM) of the administered surfactant reached the lungs. The dynamic lung-thorax compliance was higher in spontaneously breathing compared with mechanically ventilated animals (median, 9.9 and 0.75 ml x cm H2O(-1) x kg(-1), respectively; p < 0.05). The relative distribution of 14C-Curosurf in bronchoalveolar lavage fluid and homogenized lung tissue showed a higher degree of tissue association in the spontaneously breathing animals [53 +/- 4 versus 26 +/- 3% (mean +/- SEM)] than in mechanically ventilated animals (p < 0.01), the latter figure being very similar to that of the control group (25 +/- 5%). There was a higher degree of lipid peroxidation and fewer microbubbles in bronchoalveolar lavage fluid from mechanically ventilated animals. We conclude that the initial lung tissue association of exogenous surfactant is impaired by mechanical ventilation. This is associated with a reduction of dynamic compliance and evidence of increased surfactant inactivation.
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Affiliation(s)
- Kajsa Bohlin
- Division of Pediatrics, Department of Clinical Science Karolinka University Hospital Huddinge, SE-141 86, Stockholm, Sweden. kajsa@
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Monkman SL, Andersen CC, Nahmias C, Ghaffer H, Bourgeois JM, Roberts RS, Schmidt B, Kirpalani HM. Positive end-expiratory pressure above lower inflection point minimizes influx of activated neutrophils into lung*. Crit Care Med 2004; 32:2471-5. [PMID: 15599153 DOI: 10.1097/01.ccm.0000147832.13213.1e] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To compare the effects of low vs. high tidal volume (Vt) with three positive end-expiratory pressure (PEEP) strategies on activated neutrophil influx into the lung. DESIGN Prospective, randomized controlled animal study. SETTING Animal laboratory in a university hospital. SUBJECTS Newborn piglets. INTERVENTIONS Surfactant-depleted piglets were randomized in littermate pairs; to PEEP of either 0 (zero end-expiratory pressure [ZEEP]; n = 6), 8 cm H2O (PEEP 8; n = 5), or 1 cm H2O above the lower inflection point (LIP) (PEEP>LIP; n = 6). Within each pair piglets were randomized to a low VT (5-7 mL/kg) or high VT strategy (17-19 mL/kg). After 4 hrs of mechanical ventilation, 18-fluorodeoxyglucose (18FDG) was injected and positron emission tomography scanning was performed. MEASUREMENTS AND MAIN RESULTS VT and PEEP changes on influx constants of 18FDG were assessed by analysis of variance. A within-litter comparison of Vt was nonsignificant (p = .50). A between-litter comparison, ordered in linear trend rank, from ZEEP, to PEEP 8, to PEEP>LIP, showed a strong effect of PEEP on influx constant (p = .019). CONCLUSIONS PEEP set above the LIP on the inspiratory limb of the pressure-volume curve affords a stronger lung protection than VT strategy.
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Affiliation(s)
- Shelley L Monkman
- Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
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20
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Anderson JC, Molthen RC, Dawson CA, Haworth ST, Bull JL, Glucksberg MR, Grotberg JB. Effect of ventilation rate on instilled surfactant distribution in the pulmonary airways of rats. J Appl Physiol (1985) 2004; 97:45-56. [PMID: 14990558 DOI: 10.1152/japplphysiol.00609.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Liquid can be instilled into the pulmonary airways during medical procedures such as surfactant replacement therapy, partial liquid ventilation, and pulmonary drug delivery. For all cases, understanding the dynamics of liquid distribution in the lung will increase the efficacy of treatment. A recently developed imaging technique for the study of real-time liquid transport dynamics in the pulmonary airways was used to investigate the effect of respiratory rate on the distribution of an instilled liquid, surfactant, in a rat lung. Twelve excised rat lungs were suspended vertically, and a single bolus (0.05 ml) of exogenous surfactant (Survanta, Ross Laboratories, Columbus, OH) mixed with radiopaque tracer was instilled as a plug into the trachea. The lungs were ventilated with a 4-ml tidal volume for 20 breaths at one of two respiratory rates: 20 or 60 breaths/min. The motion of radiodense surfactant was imaged at 30 frames/s with a microfocal X-ray source and an image intensifier. Dynamics of surfactant distribution were quantified for each image by use of distribution statistics and a homogeneity index. We found that the liquid distribution depended on the time to liquid plug rupture, which depends on ventilation rate. At 20 breaths/min, liquid was localized in the gravity-dependent region of the lung. At 60 breaths/min, the liquid coated the airways, providing a more vertically uniform liquid distribution.
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Affiliation(s)
- Joseph C Anderson
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109-2099, USA
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21
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van Kaam AH, Haitsma JJ, Dik WA, Naber BA, Alblas EH, De Jaegere A, Kok JH, Lachmann B. Response to exogenous surfactant is different during open lung and conventional ventilation. Crit Care Med 2004; 32:774-80. [PMID: 15090961 DOI: 10.1097/01.ccm.0000114578.48244.21] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Previous studies have shown that the efficacy of exogenous surfactant is dose-dependent during conventional positive pressure ventilation (PPVCON). The present study aimed to determine whether this dose-dependent relationship is also present during open lung (OLC) ventilation. We also explored the effect of exogenous surfactant on the ventilation pressures applied during ventilation. DESIGN Animal study. SETTING University-affiliated research laboratory. SUBJECTS Seventy-two newborn piglets. INTERVENTIONS After repeated whole lung lavage, animals were randomly allocated to two surfactant groups receiving either 100 mg/kg surfactant (S100) or 25 mg/kg surfactant (S25) or to a control group receiving a bolus of air. Within each group, animals were randomly assigned to either PPVCON, open lung PPV (PPVOLC), or open lung high-frequency oscillatory ventilation (HFOVOLC) and ventilated for 5 hrs. MEASUREMENTS AND MAIN RESULTS The ventilation pressures decreased in a dose-dependent way, showing the largest reduction in the S100 group. In both OLC groups, oxygenation, lung mechanics, and polymorphonuclear neutrophils analyzed in bronchoalveolar lavage were independent of the surfactant dose. In the PPVCON group, however, there was a clear dose-dependency, resulting in a deterioration of oxygenation and lung mechanics and an increase in polymorphonuclear neutrophils as the surfactant dose decreased. Although comparable between the three ventilation groups, bronchoalveolar lavage interleukin-8 concentrations significantly increased in all ventilation groups as the surfactant dose increased. Alveolar protein influx and conversion of large to small aggregate surfactant were higher during PPVCON compared with both OLC groups. There were no differences in the surfactant treatment response between PPVOLC and HFOVOLC. CONCLUSION Exogenous surfactant enables a reduction in ventilation pressures. Compared with PPVCON, the efficacy of surfactant treatment is less dose-dependent during open lung ventilation. Surfactant conversion during open lung ventilation is reduced compared with PPVCON. Exogenous surfactant seems to up-regulate bronchoalveolar lavage interleukin-8 concentrations, independent of the ventilation strategy.
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Affiliation(s)
- Anton H van Kaam
- Department of Anesthesiology, Erasmus-MC Faculty, Rotterdam, The Netherlands
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22
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Abstract
Mechanical ventilation is a complex therapy with several different parameters which can be altered. In preterm and term infants, more attention has been paid to the levels of peak inspiratory pressure than to the positive end-expiratory pressure (PEEP). An awareness that lung protection can be conferred by an appropriate level of PEEP has increasingly stimulated a renewed interest in achieving the "best PEEP" strategy. We review the history of the introduction of PEEP therapy, some of the early demonstrations of its potential for mischief, the evidence on what levels of PEEP are appropriate in infants, some data concerning the lung-protective value of PEEP and finally some recent efforts at defining measures to determine the so-called "best PEEP". Some of this work has been performed in adults with the acute respiratory distress syndrome. In newborns, we are regrettably forced to conclude that there is, for the immediate present, no easy substitute for sensible clinical observations coupled with a judicious and cautious adjustment of PEEP. We anticipate that a more logical application of PEEP with individualisation of therapy, based on a pressure-volume relationship, will in future enable targeted tests of PEEP as a lung-protection strategy.
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Affiliation(s)
- Shelley Monkman
- Neonatal Intensive Care Unit, Department of Paediatrics, McMaster University Medical Centre, Hamilton, Ontario, Canada
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23
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Abstract
Exogenous surfactant therapy has been a significant advance in the management of preterm infants with RDS. It has become established as a standard part of the management of such infants. Both natural and synthetic surfactants lead to clinical improvement and decreased mortality, with natural surfactants having additional advantages over currently available synthetic surfactants. The use of prophylactic surfactant administered after initial stabilization at birth to infants at risk for RDS has benefits compared with rescue surfactant given to treat infants with established RDS. In infants who do not receive prophylaxis, earlier treatment (before 2 hours) has benefits over later treatment. The use of multiple doses of surfactant is a superior strategy to the use of a single dose, whereas the use of a higher threshold for retreatment seems to be as effective as a low threshold. Adverse effects of surfactant therapy are infrequent and usually not serious. Long-term follow-up of infants treated with surfactant in the neonatal period is reassuring. In the future we are likely to see the development of new types of surfactants. Further research is required to determine the optimal use of surfactant in conjunction with other respiratory interventions.
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Affiliation(s)
- G K Suresh
- Neonatal Division, Department of Pediatrics, University of Vermont College of Medicine, Burlington, Vermont, USA.
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24
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Milligan DW, Ainsworth SB. Animal-derived or synthetic surfactant for the treatment of neonatal respiratory distress syndrome: a review. ACTA PAEDIATRICA (OSLO, NORWAY : 1992). SUPPLEMENT 2001; 90:25-7. [PMID: 11332952 DOI: 10.1111/j.1651-2227.2001.tb01625.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Animal-derived surfactants containing SP-B and SP-C are more effective in vitro and in animal models than their synthetic counterparts, but are not as effective as unmodified, naturally occurring surfactant. In clinical trials involving newborn babies with respiratory distress syndrome (RDS) these short-term differences are reflected as improvements in gas exchange and lung function. Treatment with animal-derived surfactants results in fewer air leaks and lower neonatal mortality. The evidence is now strong enough to recommend routine use of animal-derived surfactants in very preterm infants with RDS. The newer generation of synthetic surfactants may be important in the future as they have the advantages of currently available animal products with the addition of better resistance to inactivation.
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Affiliation(s)
- D W Milligan
- Newcastle Neonatal Service, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
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25
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Allen V, Oulton M, Stinson D, MacDonald J, Allen A. Alveolar metabolism of natural vs. synthetic surfactants in preterm newborn rabbits. J Appl Physiol (1985) 2001; 90:198-204. [PMID: 11133911 DOI: 10.1152/jappl.2001.90.1.198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We compared the recoveries of four surfactant preparations: two natural [term fetal rabbit surfactant (FRS) and adult rabbit surfactant (ARS)] and two commercially available preparations [apoprotein-based Survanta (S) and synthetic Exosurf (E)] from 27-day gestation rabbit pups treated at birth and ventilated up to 120 min. At 5, 60, and 120 min, we measured the recovery of the heavy-aggregate, metabolically active form (H) and the light-aggregate, nonsurface active metabolic breakdown form (L) of alveolar surfactant and determined the phospholipid content and composition of the intracellularly stored lamellar body (LB) pool. Pups treated with FRS had <15% loss of H by 2 h. ARS-treated pups had a >50% loss of H by 1 h, and E- and S-treated pups had approximately 50% loss by 5 min, with a slower rate of continuing loss of up to 80% by 2 h. The major losses of H phospholipid were not explained by the L-form recovery. LB phospholipid significantly increased only in the E-treated pups and only at 2 h. FRS provides a biologically active form (H) of surfactant that appeared to remain in the airway for a significantly longer time than the other surfactant preparations. The unique properties of FRS merit further study.
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Affiliation(s)
- V Allen
- Department of Obstetrics/Gynaecology, Dalhousie University and IWK Grace Health Centre, Halifax, Nova Scotia, Canada
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26
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Affiliation(s)
- A H Jobe
- Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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27
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Mrozek JD, Bendel-Stenzel EM, Meyers PA, Bing DR, Connett JE, Mammel MC. Randomized controlled trial of volume-targeted synchronized ventilation and conventional intermittent mandatory ventilation following initial exogenous surfactant therapy. Pediatr Pulmonol 2000; 29:11-8. [PMID: 10613781 DOI: 10.1002/(sici)1099-0496(200001)29:1<11::aid-ppul3>3.0.co;2-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We set out to evaluate the impact of volume-targeted synchronized ventilation and conventional intermittent mandatory ventilation (IMV) on the early physiologic response to surfactant replacement therapy in neonates with respiratory distress syndrome (RDS). We hypothesized that volume-targeted, patient-triggered synchronized ventilation would stabilize minute ventilation at a lower respiratory rate than that seen during volume-targeted IMV, and that synchronization would improve oxygenation and decrease variation in measured tidal volume (V(t)). This was a prospective, randomized study of 30 hospitalized neonates with RDS. Infants were randomly assigned to volume-targeted ventilation using IMV (n = 10), synchronized IMV (SIMV; n = 10), or assist/control ventilation (A/C; n = 10) after meeting eligibility requirements and before initial surfactant treatment. Following measurements of arterial blood gases and cardiovascular and respiratory parameters, infants received surfactant. Infants were studied for 6 hr following surfactant treatment. Infants assigned to each mode of ventilation had similar birth weight, gestational age, and Apgar scores at birth, and similar oxygenation indices at randomization. Three patients were eliminated from final data analysis because of exclusionary conditions unknown at randomization. Oxygenation improved significantly following surfactant therapy in all groups by 1 hr after surfactant treatment (P < 0.05). No further improvements occurred with time. Total respiratory rate was lowest (P < 0.05) and variation in tidal volume (V(t)) was least in the A/C group (P < 0. 05). Minute ventilation (V(')(E)), delivered airway pressures, respiratory system mechanics, and hemodynamic parameters were similar in all groups. We conclude that volume-targeted A/C ventilation resulted in more consistent tidal volumes at lower total respiratory rates than IMV or SIMV. Oxygenation and lung mechanics were not altered by synchronization, possibly due to the volume-targeting strategy. Of the modes studied, A/C, a fully-synchronized mode, may be the most efficient method of mechanical ventilator support in neonates receiving surfactant for treatment of RDS.
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Affiliation(s)
- J D Mrozek
- Infant Pulmonary Research Center, Children's Hospital-St. Paul and the Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
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28
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Michna J, Jobe AH, Ikegami M. Positive end-expiratory pressure preserves surfactant function in preterm lambs. Am J Respir Crit Care Med 1999; 160:634-9. [PMID: 10430740 DOI: 10.1164/ajrccm.160.2.9902016] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ventilation style influences lung injury and the amount of large-aggregate biophysically active surfactant in adult lungs. We asked how positive end-expiratory pressures (PEEP) would influence clinical responses and surfactant pools in surfactant-treated preterm lambs ventilated for 7 h with tidal volumes (VT) of 10 ml/kg. The 126-d gestation preterms were delivered and treated with 100 mg/kg recombinant human surfactant protein C (rSP-C) containing surfactant and ventilated with zero, 4, or 7 cm H(2)O of PEEP. A comparison group was treated with natural sheep surfactant and ventilated with zero PEEP. Physiologic measurements were similar for lambs treated with rSP-C surfactant and natural surfactant. PEEP 4 and 7 improved oxygenation and compliance relative to either group of lambs ventilated with PEEP zero. The maximal lung volumes measured at 40 cm H(2)O pressure after 7 h ventilation for the PEEP 4 and 7 groups were more than double those measured for either PEEP zero group. Alveolar surfactant pools were larger for the PEEP 7 group, and the large-aggregate fraction was increased for the PEEP 4 and 7 groups, resulting in large-aggregate pool sizes that were 3-fold higher for the PEEP 4 and 4-fold higher for the PEEP 7 groups relative to the PEEP zero group treated with rSP-C surfactant. All large-aggregate surfactants lowered minimal surface tensions of a captive bubble to less than 5 mN/m. In preterm surfactant-treated lambs PEEP improved lung function and maintained more of an rSP-C surfactant in the biophysically active form.
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Affiliation(s)
- J Michna
- Division of Pulmonary Biology, Children's Hospital Medical Center, Cincinnati, Ohio, USA
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29
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Germann PG, Häfner D. A rat model of acute respiratory distress syndrome (ARDS): Part 1. Time dependency of histological and pathological changes. J Pharmacol Toxicol Methods 1998; 40:101-7. [PMID: 10100499 DOI: 10.1016/s1056-8719(98)00048-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The time course of histopathological changes in a rat lung lavage model of the acute respiratory distress syndrome (ARDS) was analyzed by sacrificing animals 10, 30, 60, 180, and 210 min after the last lung parenchyma lavage which was performed with physiological saline solution. This lavage depleted the lung from its natural surfactant resources leading into a pathophysiological cascade similar to that of the acute respiratory distress syndrome. Tracheotomized rats (12 animals per time point) were pressure-controlled ventilated (Siemens Servo Ventilator 900C) with 100% oxygen at a respiratory rate of 30 breaths/min, inspiration-expiration ratio of 1:2, peak inspiratory pressure of 28 cm H2O at positive end-expiratory pressure (PEEP) of 8 cm H2O. During the whole experimental period, the ventilation was not changed. Blood gases (partial arterial oxygen pressures [PaO2, mmHg] and partial arterial carbon dioxide pressures [PaCO2, mmHg]) were estimated before, directly after, and 10, 30, 60, 90, 120, 150, 180, and 210 min after the last lavage. For grading lung lavage-induced histopathological changes associated with the time-dependent development of ARDS, slides were coded and evaluated without any knowledge of the sacrifice time. A semiquantitative grading was performed with respect to the severity of the following parameters: hyaline membrane formation (HM), interstitial and intraalveolar edema edema (E), and margination and infiltration of polymorphonuclear neutrophil leukocytes (PMNL) into the lung alveoli. The severity of these parameters showed a time-dependent increase after the last lavage. This was accompanied by a time-dependent decrease in partial arterial oxygen pressure (PaO2) values during the early postlavage period (up to 30 min). Thereafter, PaO2 levels remained fairly stable. The severity of intraalveolar and/or perivascular hemorrhages within the lung was not time dependent. The rat lavage model shows similarities to the pathophysiological sequelae occuring during the acute phase of the acute respiratory distress syndrome in humans. Most of the characteristic pathognomic histological changes seen in humans can be observed in this lung lavage model. This ARDS model is brief and easy in its experimental design, showed a good and homogeneous reproducibility of pathophysiological and histopathological parameters, and is therefore a useful model to estimate the influence of therapeutic pharmacological treatments of ARDS.
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Affiliation(s)
- P G Germann
- Institute of Pathology and Toxicology, Byk Gulden, Hamburg, Germany
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30
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Halpern D, Jensen OE, Grotberg JB. A theoretical study of surfactant and liquid delivery into the lung. J Appl Physiol (1985) 1998; 85:333-52. [PMID: 9655794 DOI: 10.1152/jappl.1998.85.1.333] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A computational study is presented for the transport of liquids and insoluble surfactant through the lung airways, delivered from a source at the distal end of the trachea. Four distinct transport regimes are considered: 1) the instilled bolus may create a liquid plug that occludes the large airways but is forced peripherally during mechanical ventilation; 2) the bolus creates a deposited film on the airway walls, either from the liquid plug transport or from direct coating, that drains under the influence of gravity through the first few airway generations; 3) in smaller airways, surfactant species form a surface layer that spreads due to surface-tension gradients, i.e., Marangoni flows; and 4) the surfactant finally reaches the alveolar compartment where it is cleared according to first-order kinetics. The time required for a quasi-steady-state transport process to evolve and for the subsequent delivery of the dose is predicted. Following fairly rapid transients, on the order of seconds, steady-state transport develops and is governed by the interaction of Marangoni flow and alveolar kinetics. Total delivery time is approximately 24 h for a typical first dose. Numerical solutions show that both transit and delivery times are strongly influenced by the strength of the preexisting surfactant and the geometric properties of the airway network. Delivery times for follow-up doses can increase significantly as the level of preexisting surfactant rises.
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Affiliation(s)
- D Halpern
- Department of Mathematics, University of Alabama, Tuscaloosa, Alabama 35487, USA
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31
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Walther FJ, Hernández-Juviel J, Bruni R, Waring AJ. Protein composition of synthetic surfactant affects gas exchange in surfactant-deficient rats. Pediatr Res 1998; 43:666-73. [PMID: 9585014 DOI: 10.1203/00006450-199805000-00016] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Synthetic surfactant peptides offer an opportunity to standardize the protein composition of surfactant. We tested the effect of phospholipids (PL) with synthetic full-length SP-B1-78 (B), mutant B (Bser), KL4 peptide (UCLA-KL4), and palmitoylated SP-C1-35 (C) on oxygenation and lung function in a surfactant-deficient rat model. Sixty-four adult rats were ventilated with 100% oxygen, a tidal volume of 7.5 mL/kg, and a rate of 60/min. Their lungs were lavaged with saline until the arterial PO2 dropped below 80 torr, when 100 mg/kg surfactant was instilled. Surfactant preparations included: PL (PL surfactant), PL + 3% B (B surfactant), PL + 3% B and 1% C (BC surfactant), PL + 3% UCLA-KL4 (KL4 surfactant), PL + 3% Bser (Bser surfactant), and PL + 3% B and 1% UCLA-KL4 (BKL4 surfactant). Sixty minutes after surfactant instillation, positive end-expiratory pressure was applied for 5 min, and pressure-volume curves were determined in situ. The six surfactant preparations had a minimum surface tensions <10 mN/m on a Langmuir/Wilhelmy balance. Instillation of PL, Bser, and BKL4 surfactant increased mean arterial/alveolar PO2 (aADO2) ratios by 50-100% over postlavage values, whereas KL4 surfactant increased aADO2 ratios by 118%, B surfactant by 191%, and BC surfactant by 225%. Lung volumes at 30 cm H2O pressure were highest after treatment with BC surfactant, intermediate after B and KL4 surfactants, and lowest after BKL4, Bser, and PL surfactants. These data suggest that a surfactant preparation with a combination of synthetic B and C peptides surpasses synthetic B and KL4 surfactants in improving oxygenation and lung compliance in surfactant-deficient rats.
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Affiliation(s)
- F J Walther
- Department of Pediatrics, Charles R. Drew University of Medicine and Science, Los Angeles, California 90059, USA
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Krause MF, Schulte-Mönting J, Hoehn T. Rate of surfactant administration influences lung function and gas exchange in a surfactant-deficient rabbit model. Pediatr Pulmonol 1998; 25:196-204. [PMID: 9556012 DOI: 10.1002/(sici)1099-0496(199803)25:3<196::aid-ppul10>3.0.co;2-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The aim of this study was to test whether the effect of surfactant treatment on lung function in a surfactant-deficient animal model can be influenced by the rate at which surfactant is administered. Surfactant deficiency was induced in 18 New Zealand white rabbits (weighing approx. 1 kg each) by lung lavage with normal saline. The arterial/alveolar oxygen ratio (a/A ratio), functional residual capacity (FRC), dynamic compliance of the respiratory system (Crs), tidal volume (V(T)), alveolar portion of the tidal volume (V(A)) and arterial P(CO2) (P(a,CO2)) were measured before and after lavage and 15, 30, 60, 90, and 120 min after administration of a single dose of surfactant (Survanta, 100 mg/kg). Two surfactant administration protocols were compared over a 2-h interval: an infusion lasting 4 min and an infusion over 2 min. Both administrations were given during continuous mechanical ventilation. The six lung function and gas exchange parameters improved significantly following surfactant administration over 2 min compared with a control group. However, only the a/A ratio and V(A) improved following the 4-min protocol. Comparison of the two intervention protocols yielded significantly differences in V(A) and P(a,CO2), favoring the shorter administration. These results support the hypothesis that fast (2 min) administration of surfactant will improve its distribution to formerly collapsed alveoli and results in better lung function, improved ventilation, and (to a lesser extent) better oxygenation than prolonged infusions (4 min).
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Affiliation(s)
- M F Krause
- Department of Pediatrics, Albert-Ludwigs University, University Hospital, Freiburg, Germany
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Ikegami M, Wada K, Emerson GA, Rebello CM, Hernandez RE, Jobe AH. Effects of ventilation style on surfactant metabolism and treatment response in preterm lambs. Am J Respir Crit Care Med 1998; 157:638-44. [PMID: 9476883 DOI: 10.1164/ajrccm.157.2.9704006] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We investigated whether the style of ventilation would influence respiratory physiology or surfactant metabolism in surfactant-treated preterm lambs. Preterm lambs were delivered at 131 +/- 1 d gestation and treated with an organic solvent extract of sheep surfactant (100 mg/kg). The lambs were randomized to ventilation peiods of 2 h, 5 h, 10 h, or 24 h, and to ventilation with a low rate (15 breaths/min) and high VT (15 ml/kg), with a high rate (50 breaths/min) and low VT (8 ml/kg), or with high-frequency oscillatory ventilation (HFOV). Gas exchange and lung volumes were similar across time and for the different ventilation styles. Saturated phosphatidylcholine (SatPC) in alveolar lavage was lower for the HFOV group than for the other ventilation groups at 10 h and 24 h. The rate of loss of surfactant protein B (SP-B) from these preterm animals' lungs was slow and not influenced by ventilation style. The percentages of surfactants in large-aggregate forms were not changed by style of ventilation, and the large-aggregate surfactants had excellent function when tested in surfactant-deficient preterm rabbits. Alveolar lavage protein was low (30 ml/kg), and tissue hyaluronan did not change with time or ventilation style. In preterm lambs ventilated without causing injury, the extreme styles of ventilation examined in the study had minimal effects on lung function, surfactant function, or surfactant metabolism.
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Affiliation(s)
- M Ikegami
- Department of Pediatrics, Harbor UCLA Medical Center, Torrance, California, USA
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Wada K, Jobe AH, Ikegami M. Tidal volume effects on surfactant treatment responses with the initiation of ventilation in preterm lambs. J Appl Physiol (1985) 1997; 83:1054-61. [PMID: 9338410 DOI: 10.1152/jappl.1997.83.4.1054] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We hypothesized that initiation of ventilation in preterm lambs with high volumes would cause lung injury and decrease the subsequent response to surfactant treatment. Preterm lambs were randomized to ventilation for 30 min after birth with 5 ml/kg (VT5), 10 ml/kg (VT10), or 20 ml/kg (VT20) tidal volumes and then ventilated with approximately 10 ml/kg tidal volumes to achieve arterial PCO2 values of approximately 50 Torr to 6 h of age. VT20 lambs had lower compliances, lower ventilatory efficiencies, higher recoveries of protein, and lower recoveries of surfactant in alveolar lavages and in surfactant that had decreased compliances when tested in preterm rabbits than VT5 or VT10 lambs. Other lambs randomized to treatment with surfactant at birth and ventilation with 6, 12, or 20 ml/kg tidal volumes for 30 min had no indicators of lung injury. An initial tidal volume of 20 ml/kg decreased the subsequent response to surfactant treatment, an effect that was prevented with surfactant treatment at birth.
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Affiliation(s)
- K Wada
- Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, California 90502, USA
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Krause M, Olsson T, Law AB, Parker RA, Lindstrom DP, Sundell HW, Cotton RB. Effect of volume recruitment on response to surfactant treatment in rabbits with lung injury. Am J Respir Crit Care Med 1997; 156:862-6. [PMID: 9310005 DOI: 10.1164/ajrccm.156.3.9507096] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We determined if surfactant treatment effect can be enhanced by mechanical volume recruitment during surfactant administration by measuring functional residual capacity, tidal volume, the alveolar portion of tidal volume, dynamic compliance of the respiratory system, a/A ratio, and PaCO2 by measuring before and after surfactant administration to rabbits with lung injury induced by airway lavage. There was improvement in all lung function indices when surfactant was given with volume recruitment, but when surfactant was given without volume recruitment, the only index to show significant improvement was a/A ratio of oxygenation. These results support the hypothesis that mechanical recruitment of terminal airspaces from a previously unventilated compartment will enhance the effectiveness of surfactant replacement by facilitating the distribution of instilled surfactant to this compartment.
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Affiliation(s)
- M Krause
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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Walther FJ, Hernández-Juviel J, Bruni R, Waring AJ. Spiking Survanta with synthetic surfactant peptides improves oxygenation in surfactant-deficient rats. Am J Respir Crit Care Med 1997; 156:855-61. [PMID: 9310004 DOI: 10.1164/ajrccm.156.3.9611053] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The hypothesis that the in vivo function of Survanta (Beractant) can be improved by supplementation with synthetic surfactant peptides B and C was tested in a surfactant-deficient rat model. Full length surfactant protein-B (SP-B1-78) (B) and palmitoylated surfactant protein-C (SP-C1-35) (C), and synthetic KL4 peptide were added to Survanta after extraction, creating extracted Survanta (ES) with 1% B, 2% B, and 2% B plus 1% C, or mixed with Survanta without extraction, creating modified Survanta (S) with 2% B, 2% B plus 1% C, and 2% KL4. Adult rats were ventilated with 100% oxygen, tidal volumes (VT) of 7.5 ml/kg and a rate of 60/min, and were lavaged until the PaO2 dropped below 80 mm Hg, when 100 mg/kg of surfactant was instilled. After 15 to 60 min of ventilation, pressure-volume (P-V) curves were generated in situ. Instillation of ES or S with 2% B plus 1% C led to the greatest increase in oxygenation, closely followed by ES and S with 2% B, and more distantly by S plus 2% KL4. TLC was comparable among the ES and S groups, but greater than that of air-placebo controls. These data suggest that spiking of Survanta with synthetic SP-B and SP-C increased oxygenation more effectively than B or KL4 alone in this surfactant-deficient rat model.
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Affiliation(s)
- F J Walther
- Department of Pediatrics, Charles R. Drew University of Medicine and Science, Los Angeles, California, USA
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Herting E, Sun B, Jarstrand C, Curstedt T, Robertson B. Surfactant improves lung function and mitigates bacterial growth in immature ventilated rabbits with experimentally induced neonatal group B streptococcal pneumonia. Arch Dis Child Fetal Neonatal Ed 1997; 76:F3-8. [PMID: 9059178 PMCID: PMC1720614 DOI: 10.1136/fn.76.1.f3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
AIMS To study the influence of surfactant on lung function and bacterial proliferation in immature newborn rabbits with experimental group B streptococcal (GBS) pneumonia. METHODS Preterm rabbit fetuses (gestational age 28 days) underwent tracheotomy and were mechanically ventilated in a warmed body plethysmograph that permitted measurement of lung-thorax compliance. Fifteen minutes after the onset of ventilation the animals received either GBS or saline intratracheally; at 30 minutes, a bolus of saline or 200 mg/kg of a porcine surfactant (Curosurf) was administered via the airway. Bacterial proliferation was evaluated in lung homogenate at the end of the experiments and the results expressed as mean log10 cfu/g lung (SD). Animals receiving only saline (n = 20) or saline and surfactant (n = 20) served as controls. RESULTS The average survival time was about three hours in all groups. Infected animals receiving surfactant (n = 22) had significantly less bacterial growth (9.09 (0.45) vs 9.76 (0.91)) and improved lung function (compliance: 0.61 (0.14) vs 0.34 (0.19) ml/kg. cm H2O) than infected rabbits receiving saline at 30 minutes (n = 22). CONCLUSION Surfactant improves lung function and mitigates bacterial growth in preterm rabbits infected with group B streptococci.
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Affiliation(s)
- E Herting
- Department of Paediatrics, University of Göttingen, Germany
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Corcoran JD, Berggren P, Sun B, Halliday HL, Robertson B, Curstedt T. Comparison of surface properties and physiological effects of a synthetic and a natural surfactant in preterm rabbits. Arch Dis Child Fetal Neonatal Ed 1994; 71:F165-9. [PMID: 7820710 PMCID: PMC1061118 DOI: 10.1136/fn.71.3.f165] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
AIMS To compare the physical and physiological properties of a synthetic surfactant (Exosurf, Wellcome Foundation) and a natural surfactant (Curosurf, Chiesi Farmaceutici). METHODS Surface properties of the surfactant suspensions (10 mg phospholipid/ml) were evaluated using the pulsating bubble surfactometer. Lung-thorax compliance was determined in 47 immature newborn rabbits with a gestational age of 27 days, treated with recommended clinical doses of either surfactant (Exosurf 67.5 mg/kg; Curosurf 200 mg/kg). The lungs were examined histologically. RESULTS The mean (SD) contractile forces of the surface at maximum and minimum bubble size were significantly lower for Curosurf than for Exosurf: 31 (2) and 0 (0) mN/m v 53 (5) and 29 (4) mN/m, respectively. Mean (SD) lung-thorax compliance after one hour of ventilation was significantly higher in rabbits treated with Curosurf compared with animals receiving Exosurf or those serving as controls: 0.60 (0.15) ml/cm H2O.kg v 0.44 (0.03) and 0.34 (0.18) ml/cm H2O.kg, respectively. Both surfactants increased alveolar volume density compared with results for control animals, but only Curosurf significantly reduced the incidence of moderate or severe bronchiolar epithelial disruption. CONCLUSIONS The natural surfactant, Curosurf, reduced the contractile force at an air-liquid interface to a greater extent than the synthetic surfactant, Exosurf, and led to a greater improvement in compliance and less airway epithelial damage when given in clinical treatment doses to immature rabbits.
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Affiliation(s)
- J D Corcoran
- Department of Child Health, Queen's University, Belfast
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Abstract
It is well recognised that reducing positive end expiratory pressure (PEEP) leads to an increase in the tidal volume and minute volume in ventilated neonates. The magnitude of this effect is perhaps not commonly appreciated, however. Effectively, PEEP is four times as potent as peak inflation pressure (PIP) in bringing about changes in tidal volume. The influence of changes in PEEP and PIP on tidal volume and the relative magnitude of each are considered. Twenty one preterm infants were studied on 38 separate occasions. All were sedated, paralysed, and ventilated, 19 for hyaline membrane disease. A 1 cm H2O reduction in PEEP was twice as potent as a 2 cm H2O increase in PIP in achieving an increase in tidal volume (14 v 7%). Similarly, increasing PEEP by 1 cm H2O was twice as effective as a 2 cm H2O decrease in PIP in reducing tidal volume (13 v 6%). Small (0.5-1 cm H2O) changes in PEEP can often be used to improve ventilation and carbon dioxide elimination. Levels of PEEP of 4-5 cm H2O may, at times, impair gas exchange and contribute to overdistension.
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Ikegami M, Ueda T, Absolom D, Baxter C, Rider E, Jobe AH. Changes in exogenous surfactant in ventilated preterm lamb lungs. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1993; 148:837-44. [PMID: 8214937 DOI: 10.1164/ajrccm/148.4_pt_1.837] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Preterm lambs were treated with either a surfactant from bovine lung (Survanta) or three synthetic surfactants (Exosurf), a 69:22:9 mixture of dipalmitoylphosphatidylcholine, phosphatidylglycerol, and palmitic acid prepared by heat annealing (Lipid Mixture 1) or with glass beads (Lipid Mixture 2). After 5 h of ventilation, large and small aggregate surfactant fractions were isolated from alveolar washes by centrifugation. SP-A was used as an indicator for the association of endogenous surfactant components with the treatment surfactants. The large aggregate fraction from Survanta-treated lambs contained more SP-A than did the fractions from the lambs treated with the other surfactants (p < 0.05). The surfactants used to treat the sheep and the large aggregate surfactants from alveolar washes increased compliances when tested in surfactant-deficient, immature rabbits, relative to that in control animals. The large aggregate fractions in alveolar washes from lambs treated with Survanta, Lipid Mixture 1, and Lipid Mixture 2 improved compliances in the preterm rabbits to a greater extent than did the surfactants used to treat the lambs. The small aggregate fractions were inactive as surfactants. The function of exogenous surfactant can be improved after exposure to the preterm lung. The improvement may result from the association of exogenous surfactant with components of endogenous surfactant.
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Affiliation(s)
- M Ikegami
- Harbor-UCLA Medical Center, UCLA School of Medicine, Department of Pediatrics, Torrance 90502
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Affiliation(s)
- A H Jobe
- Department of Pediatrics, Harbor-UCLA Medical Center, Torrance 90509
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Rider ED, Ikegami M, Whitsett JA, Hull W, Absolom D, Jobe AH. Treatment responses to surfactants containing natural surfactant proteins in preterm rabbits. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1993; 147:669-76. [PMID: 8442604 DOI: 10.1164/ajrccm/147.3.669] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The in vivo function of surfactants reconstituted using natural surfactant lipid and protein constituents was evaluated in 27-day-gestation preterm rabbits. The animals were treated with protein-free surfactant lipids (LH-20), LH-20 + 5% SP-A, LH-20 + 1% SP-B, LH-20 + 1% SP-C, LH-20 + 5% SP-A + 1% SP-B + 1% SP-C (SP-ABC), natural sheep surfactant, or 4 ml/kg 0.45% NaCl (control) and then ventilated with tidal volumes of 8 ml/kg and 3 cm H2O positive end-expiratory pressure (PEEP). Ventilatory pressures (peak pressures minus PEEP) and dynamic compliances of the LH-20 + SP-C rabbits were greater (p < 0.01) than those of control, LH-20, and LH-20 + SP-A groups but lower (p < 0.05) than in the LH-20 + SP-B, LH-20 + SP-ABC, and sheep surfactant groups. Recoveries of intravascular labeled albumin in the lungs were comparable in the LH-20 + SP-B, LH-20 + SP-C, LH-20 + SP-ABC, and sheep surfactant groups and less (p < 0.01) than in LH-20 + SP-A rabbits, which had lower (p < 0.05) recoveries than did the control and LH-20 groups. The postventilation pressure-volume curves for LH-20 + SP-B and LH-20 + SP-ABC rabbits had significantly lower opening pressures, larger maximal lung volumes, and larger retained volumes on deflation relative to the LH-20 + SP-C, LH-20, and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- E D Rider
- Harbor-UCLA Medical Center, Department of Pediatrics, Torrance 90502
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