51
|
Daily practice of mechanical ventilation in Italian pediatric intensive care units: a prospective survey. Pediatr Crit Care Med 2011; 12:141-6. [PMID: 20351615 DOI: 10.1097/pcc.0b013e3181dbaeb3] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To assess how children requiring endotracheal intubation are mechanically ventilated in Italian pediatric intensive care units (PICUs). DESIGN A prospective, national, observational, multicenter, 6-month study. SETTING Eighteen medical-surgical PICUs. PATIENTS A total of 1943 consecutive children, aged 0-16 yrs, admitted between November 1, 2006 and April 30, 2007. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Data on cause of respiratory failure, length of mechanical ventilation (MV), mode of ventilation, use of specific interventions were recorded for all children requiring endotracheal intubation for >24 hrs. Children were stratified for age, type of patient, and cause of respiratory failure. A total of 956 (49.2%) patients required MV via an endotracheal tube; 673 (34.6%) were ventilated for >24 hrs. The median length of MV was 4.5 days for all patients. If postoperative patients were excluded, the median time was 5 days. Bronchiolitis (6.7%), pneumonia (6.7%), and upper airway obstruction (5.3%) were the most frequent causes of acute respiratory failure, and altered mental status (9.2%) was the most frequent reason for MV. The overall mortality was 6.7% with highest rates for heart disease (nonoperative), sepsis, and acute respiratory distress syndrome (26.1%, 22.2%, and 16.7% respectively). Length of stay, associated chronic disease, severity score on admission, and PICU mortality were significantly higher in children who received MV (p < .05) than in children who did not. Controlled MV and pressure support ventilation + synchronized intermittent mandatory ventilation were the most frequently used modes of ventilatory assistance during PICU stay. CONCLUSIONS Mechanical ventilation is frequently used in Italian PICUs with almost one child of two requiring endotracheal intubation. Children treated with MV represent a more severe category of patients than children who are breathing spontaneously. Describing the standard care and how MV is performed in children can be useful for future clinical studies.
Collapse
|
52
|
The practice of mechanical ventilation in pediatrics: science, art, or a simple routine? Pediatr Crit Care Med 2011; 12:219-21. [PMID: 21646944 DOI: 10.1097/pcc.0b013e3181d9c71b] [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: 11/27/2022]
|
53
|
Secretory phospholipase A₂ pathway during pediatric acute respiratory distress syndrome: a preliminary study. Pediatr Crit Care Med 2011; 12:e20-4. [PMID: 20351613 DOI: 10.1097/pcc.0b013e3181dbe95e] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVE To verify if secretory phospholipase A2 (sPLA2) is increased in pediatric acute respiratory distress syndrome (ARDS) triggered or not by respiratory syncytial virus infection and to clarify how the enzyme may influence the disease severity and the degree of ventilatory support. DESIGN Prospective pilot study. SETTING Two academic pediatric intensive care units. PATIENTS All infants < 6 months old hospitalized for severe respiratory syncytial virus bronchiolitis, who developed ARDS (respiratory syncytial virus-ARDS group); all infants < 6 months old diagnosed with ARDS secondary to other causes (ARDS group); and infants < 6 months old who needed ventilation for reasons other than any lung disease (control group). INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS We enrolled six respiratory syncytial virus -ARDS babies, five ARDS babies, and six control infants. The sPLA2 activity and tumor necrosis factor (TNF)-α were significantly higher in the bronchoalveolar lavage of ARDS infants. Worst oxygenation, ventilation, and longer pediatric intensive care unit stay and ventilation time were present in ARDS babies. No differences were found in Clara cell secretory protein and in serum cytokines levels. Because there is no correlation between bronchoalveolar lavage protein content (a marker of permeability) and sPLA2, the enzyme seems mainly produced in the alveoli. TNF-α, the main inductor of sPLA2 expression, significantly correlates with the enzyme level in the bronchoalveolar lavage. Significant positive correlations exist between sPLA2, TNF-α and oxygen need, mean airway pressure, ventilatory index, and the Murray's lung injury score. Negative correlations were also found between sPLA2, TNF-α, and Pao2/Fio2 ratio. CONCLUSIONS The sPLA2 and TNF-α are increased in ARDS and seem correlated with clinical severity, higher oxygen requirement, and more aggressive ventilation. This correlation confirms findings from adult experience and should guide further investigations on pediatric ARDS pathophysiology.
Collapse
|
54
|
Cleaved caspase-3 in lung epithelium of children who died with acute respiratory distress syndrome. Pediatr Crit Care Med 2010; 11:556-60. [PMID: 20173675 DOI: 10.1097/pcc.0b013e3181d5063c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE To investigate the extent of cleaved caspase-3 immunostaining in lung epithelial cells in children with acute respiratory distress syndrome. DESIGN Observational study in sixteen children who died with acute respiratory distress syndrome and diffuse alveolar damage. SETTING Pediatric intensive care unit. PATIENTS Sixteen children with fatal acute respiratory distress syndrome and diffuse alveolar damage. INTERVENTION None. MEASUREMENTS AND MAIN RESULTS Double immunohistochemistry for cleaved caspase-3 and (pan)cytokeratin in lung tissues obtained at autopsy. Spectral imaging was used for the quantification of immunohistochemistry colocalization of these markers. We found a wide range in the percentage of alveolar epithelial cell surface area with positive cleaved caspase-3 staining in the lungs of children with acute respiratory distress syndrome (from 1% to almost 20%). The degree of caspase-3 immunostaining in epithelial cells positively correlated with age. CONCLUSION There is a high variability in the extent of classic apoptosis in lung epithelial cells in pediatric acute respiratory distress syndrome, potentially in part dependent on age.
Collapse
|
55
|
Khemani RG, Newth CJL. The design of future pediatric mechanical ventilation trials for acute lung injury. Am J Respir Crit Care Med 2010; 182:1465-74. [PMID: 20732987 DOI: 10.1164/rccm.201004-0606ci] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Pediatric practitioners face unique challenges when attempting to translate or adapt adult-derived evidence regarding ventilation practices for acute lung injury or acute respiratory distress syndrome into pediatric practice. Fortunately or unfortunately, there appears to be selective adoption of adult practices for pediatric mechanical ventilation, many of which pose considerable challenges or uncertainty when translated to pediatrics. These differences, combined with heterogeneous management strategies within pediatric critical care, can complicate clinical practice and make designing robust clinical trials in pediatric acute respiratory failure particularly difficult. These issues surround the lack of explicit ventilator protocols in pediatrics, either computer or paper based; differences in modes of conventional ventilation and perceived marked differences in the approach to high-frequency oscillatory ventilation; challenges with patient recruitment; the shortcomings of the definition of acute lung injury and acute respiratory distress syndrome; the more reliable yet still somewhat unpredictable relationship between lung injury severity and outcome; and the reliance on potentially biased surrogate outcome measures, such as ventilator-free days, for all pediatric trials. The purpose of this review is to highlight these challenges, discuss pertinent work that has begun to address them, and propose potential solutions or future investigations that may help facilitate comprehensive trials on pediatric mechanical ventilation and define clinical practice standards.
Collapse
Affiliation(s)
- Robinder G Khemani
- University of Southern California, Children's Hospital Los Angeles, CA 90027, USA.
| | | |
Collapse
|
56
|
Dizdar EA, Aydemir C, Erdeve O, Sari FN, Oguz S, Uras N, Dilmen U. Respiratory syncytial virus outbreak defined by rapid screening in a neonatal intensive care unit. J Hosp Infect 2010; 75:292-4. [PMID: 20299133 PMCID: PMC7132464 DOI: 10.1016/j.jhin.2010.01.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Accepted: 01/13/2010] [Indexed: 11/20/2022]
Abstract
Palivizumab is currently licensed for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in infants and children with chronic lung disease, with a history of preterm birth, or with haemodynamically significant congenital heart disease, but its routine use during outbreaks in neonatal intensive care units (NICUs) is not currently recommended. Here we report an outbreak in a NICU detected during a screening trial for RSV infection using a rapid antigen test (Respi-Strip®). Eleven preterm infants in our NICU tested positive for RSV during January 2009. Subsequent testing of the remaining infants in the NICU revealed two additional asymptomatic cases. In addition to precautions against cross-infection, palivizumab prophylaxis was administered to the remaining 37 premature infants. Two days after treatment, RSV was detected in two additional infants who had become symptomatic. To our knowledge this is the largest RSV outbreak in a NICU to be identified at an early stage by rapid testing and effectively controlled by infection control measures and palivizumab prophylaxis.
Collapse
Affiliation(s)
- E A Dizdar
- Neonatal Intensive Care Unit, Zekai Tahir Burak Women's Health and Education Hospital, Hamamonu, Ankara, Turkey.
| | | | | | | | | | | | | |
Collapse
|
57
|
Zosky GR, Cannizzaro V, Hantos Z, Sly PD. Protective mechanical ventilation does not exacerbate lung function impairment or lung inflammation following influenza A infection. J Appl Physiol (1985) 2009; 107:1472-8. [DOI: 10.1152/japplphysiol.00393.2009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The degree to which mechanical ventilation induces ventilator-associated lung injury is dependent on the initial acute lung injury (ALI). Viral-induced ALI is poorly studied, and this study aimed to determine whether ALI induced by a clinically relevant infection is exacerbated by protective mechanical ventilation. Adult female BALB/c mice were inoculated with 104.5 plaque-forming units of influenza A/Mem/1/71 in 50 μl of medium or medium alone. This study used a protective ventilation strategy, whereby mice were anesthetized, tracheostomized, and mechanically ventilated for 2 h. Lung mechanics were measured periodically throughout the ventilation period using a modification of the forced oscillation technique to obtain measures of airway resistance and coefficients of tissue damping and tissue elastance. Thoracic gas volume was measured and used to obtain specific airway resistance, tissue damping, and tissue elastance. At the end of the ventilation period, a bronchoalveolar lavage sample was collected to measure inflammatory cells, macrophage inflammatory protein-2, IL-6, TNF-α, and protein leak. Influenza infection caused significant increases in inflammatory cells, protein leak, and deterioration in lung mechanics that were not exacerbated by mechanical ventilation, in contrast to previous studies using bacterial and mouse-specific viral infection. This study highlighted the importance of type and severity of lung injury in determining outcome following mechanical ventilation.
Collapse
Affiliation(s)
- Graeme R. Zosky
- Division of Clinical Science, Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Subiaco, Western Australia, Australia
| | - Vincenzo Cannizzaro
- Division of Clinical Science, Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Subiaco, Western Australia, Australia
| | - Zoltan Hantos
- Division of Clinical Science, Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Subiaco, Western Australia, Australia
| | - Peter D. Sly
- Division of Clinical Science, Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Subiaco, Western Australia, Australia
| |
Collapse
|
58
|
Abstract
BACKGROUND Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS), are devastating disorders of overwhelming pulmonary inflammation and hypoxemia, resulting in high morbidity and mortality. AIM To provide the clinician with a summary of the literature on the epidemiology, diagnosis, and an evidence-base for management of ALI/ARDS in children. DATA SELECTION PubMed search for clinical trials, selected literature review of other relevant studies on epidemiology and diagnosis. DATA SYNTHESIS AND RECOMMENDATIONS: Lower mortality combined with a relatively lower frequency of ALI/ARDS in children makes performance of clinical trials challenging. Based on expert opinion, the following are recommended: 1) avoid tidal volumes > or =10 mL/kg body weight; 2) keep plateau pressure < or =30 cm H2O, arterial pH at 7.30 to 7.45, and Pao2 60 to 80 torr (8 to 10.7 kPa) (Spo2 > or =90%); 3) provide sedation, analgesia, and stress ulcer prophylaxis; and 4) use a 10 g/dL hemoglobin threshold for packed red blood cell transfusion in unstable patients (shock or profound hypoxia). Evidence supports dropping the hemoglobin transfusion threshold to 7 g/dL once profound hypoxia and shock have resolved. Promising therapies for pediatric ALI/ARDS based on pediatric studies include endotracheal surfactant, high-frequency oscillatory ventilation, noninvasive ventilation, and use of extracorporeal membrane oxygenation as a rescue therapy. Promising therapies based on adult trials include use of corticosteroids for lung inflammation and fibrosis, use of 4 to 6 mL/kg tidal volumes and restrictive fluid management. Prone positioning, bronchodilators, inhaled nitric oxide, tight glucose control, and high-flow nasal cannula (HFNC) oxygen are therapies that require further study before they can be recommended for children with ALI/ARDS.
Collapse
|
59
|
Bem RA, Bos AP, Wösten-van Asperen RM, Bruijn M, Lutter R, Sprick MR, van Woensel JBM. Potential role of soluble TRAIL in epithelial injury in children with severe RSV infection. Am J Respir Cell Mol Biol 2009; 42:697-705. [PMID: 19635930 DOI: 10.1165/rcmb.2009-0100oc] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Lower respiratory tract infection by respiratory syncytial virus (RSV) is a frequent cause of acute lung injury in young children and infants. Studies in adults and animals suggest that tumor necrosis factor receptor (TNFR) ligands may mediate lung injury by causing apoptosis of epithelial cells. The main goal of the present study was to determine whether the TNF-related apoptosis-inducing ligand (Apo2L/TRAIL) pathway may be implicated in epithelial injury during severe RSV infection in children. We report elevated levels of soluble (s)TRAIL released by leukocytes in bronchoalveolar lavage fluid (BALF) of patients with RSV-associated respiratory failure (n = 22) as compared with mechanically ventilated patients without pulmonary illness (n = 7). Primary bronchial epithelial cells of children without pulmonary disease obtained by nonbronchoscopic cytobrushing expressed both death receptors TRAIL-R1 and -R2, and were found to be susceptible for cell death by human recombinant sTRAIL in vitro. Furthermore, BALF from a patient with RSV induced cell death in these cells, which was partly attenuated by inhibiting TRAIL signaling. These data suggest that the TRAIL pro-apoptotic pathway may contribute to lung epithelial injury in severe RSV infection in children.
Collapse
Affiliation(s)
- Reinout A Bem
- Emma Children's Hospital, Academic Medical Center, Pediatric Intensive Care Unit, P.O. Box 22660, 1100 DD Amsterdam, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
60
|
Effect of tidal volume in children with acute hypoxemic respiratory failure. Intensive Care Med 2009; 35:1428-37. [PMID: 19533092 DOI: 10.1007/s00134-009-1527-z] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 04/05/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES To determine if tidal volume (VT) between 6 and 10 ml/kg body weight using pressure control ventilation affects outcome for children with acute hypoxemic respiratory failure (AHRF) or acute lung injury (ALI). To validate lung injury severity markers such as oxygenation index (OI), PaO2/FiO2 (PF) ratio, and lung injury score (LIS). DESIGN Retrospective, January 2000-July 2007. SETTING Tertiary care, 20-bed PICU. PATIENTS Three hundred and ninety-eight endotracheally intubated and mechanically ventilated children with PF ratio <300. Outcomes were mortality and 28-day ventilator free days. MEASUREMENTS AND MAIN RESULTS Three hundred and ninety-eight children met study criteria, with 20% mortality. 192 children had ALI. Using >90% pressure control ventilation, 85% of patients achieved VT less than 10 ml/kg. Median VT was not significantly different between survivors and non-survivors during the first 3 days of mechanical ventilation. After controlling for diagnostic category, age, delta P (PIP-PEEP), PEEP, and severity of lung disease, VT was not associated with mortality (P > 0.1), but higher VT at baseline and on day 1 of mechanical ventilation was associated with more ventilator free days (P < 0.05). This was particularly seen in patients with better respiratory system compliance [Crs > 0.5 ml/cmH2O/kg, OR = 0.70 (0.52, 0.95)]. OI, PF ratio, and LIS were all associated with mortality (P < 0.05). CONCLUSIONS When ventilating children using lung protective strategies with pressure control ventilation, observed VT is between 6 and 10 ml/kg and is not associated with increased mortality. Moreover, higher VT within this range is associated with more ventilator free days, particularly for patients with less severe disease.
Collapse
|
61
|
Javouhey E, Massenavette B, Binoche A, Desprez P, Ramadan-Ghostine G, Guillermet C, Floret D, Leclerc F. Ventilation non invasive dans les détresses respiratoires aiguës du nourrisson en période d’épidémie de VRS : étude prospective multicentrique française. Arch Pediatr 2009; 16:729-31. [DOI: 10.1016/s0929-693x(09)74129-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
62
|
Abstract
Respiratory syncytial virus (RSV) lower respiratory tract disease may present as bronchiolitis, an obstructive lung disease with hyperinflation, or pneumonitis, a restrictive parenchymal disease with diffuse consolidation, a large intrapulmonary shunt and acute respiratory distress syndrome (ARDS). Although a significant proportion of those admitted to hospital will require some form of respiratory support, there have been few randomised studies to determine which is the most beneficial. Studies on the use of continuous positive airway pressure (CPAP), heliox, inhaled nitric oxide, and natural surfactant are reviewed. Current practice regarding ventilator support is largely based on clinical judgment and case reports. Multicentre randomised trials with long-term follow-ups are urgently required.
Collapse
Affiliation(s)
- Anne Greenough
- Division of Asthma, Allergy and Lung Biology, King's College London School of Medicine at Guy's, King's College and St. Thomas' Hospitals, London, UK.
| |
Collapse
|
63
|
Kneyber MCJ, van Heerde M, Twisk JWR, Plötz FB, Markhors DG. Heliox reduces respiratory system resistance in respiratory syncytial virus induced respiratory failure. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2009; 13:R71. [PMID: 19450268 PMCID: PMC2717432 DOI: 10.1186/cc7880] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 04/20/2009] [Accepted: 05/15/2009] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Respiratory syncytial virus (RSV) lower respiratory tract disease is characterised by narrowing of the airways resulting in increased airway resistance, air-trapping and respiratory acidosis. These problems might be overcome using helium-oxygen gas mixture. However, the effect of mechanical ventilation with heliox in these patients is unclear. The objective of this prospective cross-over study was to determine the effects of mechanical ventilation with heliox 60/40 versus conventional gas on respiratory system resistance, air-trapping and CO2 removal. METHODS Mechanically ventilated, sedated and paralyzed infants with proven RSV were enrolled within 24 hours after paediatric intensive care unit (PICU)admission. At T = 0, respiratory system mechanics including respiratory system compliance and resistance, and peak expiratory flow rate were measured with the AVEA ventilator. The measurements were repeated at each interval (after 30 minutes of ventilation with heliox, after 30 minutes of ventilation with nitrox and again after 30 minutes of ventilation with heliox). Indices of gas exchange (ventilation and oxygenation index) were calculated at each interval. Air-trapping (defined by relative change in end-expiratory lung volume) was determined by electrical impedance tomography (EIT) at each interval. RESULTS Thirteen infants were enrolled. In nine, EIT measurements were performed. Mechanical ventilation with heliox significantly decreased respiratory system resistance. This was not accompanied by an improved CO2 elimination, decreased peak expiratory flow rate or decreased end-expiratory lung volume. Importantly, oxygenation remained unaltered throughout the experimental protocol. CONCLUSIONS Respiratory system resistance is significantly decreased by mechanical ventilation with heliox (ISCRTN98152468).
Collapse
Affiliation(s)
- Martin C J Kneyber
- Department of Pediatric Intensive Care, VU university medical center, Amsterdam, The Netherlands.
| | | | | | | | | |
Collapse
|
64
|
Identification of gene biomarkers for respiratory syncytial virus infection in a bronchial epithelial cell line. Genomic Med 2009; 2:113-25. [PMID: 19459069 DOI: 10.1007/s11568-009-9080-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 04/14/2009] [Accepted: 04/24/2009] [Indexed: 12/26/2022] Open
Abstract
Respiratory syncytial virus (RSV) infection involves complex virus-host interplay. In this study, we analyzed gene expression in RSV-infected BEAS-2B cells to discover novel signaling pathways and biomarkers. We hybridized RNAs from RSV- or vehicle-treated BEAS-2B to Affymetrix HU133 plus 2.0 microarrays (n = 4). At 4 and 24 h post-infection, 277 and 900 genes (RSV/control ratio >/=2.0 or </=0.5), and 1 and 12 pathways respectively were significantly altered. Twenty-three and 92 genes at 4 and 24 h respectively matched respiratory disease biomarkers with ARG2 flagged at 24 h and SCNN1G, EPB41L4B, CSF1, PTEN, TUBB1 and ESR2 at both time points. Hierachical clustering showed a cluster containing ARG2 and IL8. In human bronchial epithelial cells, RSV upregulated arginase II protein. Knockdown of ARG2 increased RSV-induced IL-8, LDH and histone release. With microarray, we identified novel proximal airway epithelial cell genes that may be tested in the sputum samples as biomarkers of RSV infection.
Collapse
|
65
|
Bonville CA, Percopo CM, Dyer KD, Gao J, Prussin C, Foster B, Rosenberg HF, Domachowske JB. Interferon-gamma coordinates CCL3-mediated neutrophil recruitment in vivo. BMC Immunol 2009; 10:14. [PMID: 19298652 PMCID: PMC2662797 DOI: 10.1186/1471-2172-10-14] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2008] [Accepted: 03/19/2009] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND We have shown previously that acute infection with the respiratory pathogen, pneumonia virus of mice (PVM), results in local production of the proinflammatory chemokine, CCL3, and that neutrophil recruitment in response to PVM infection is reduced dramatically in CCL3 -/- mice. RESULTS In this work, we demonstrate that CCL3-mediated neutrophil recruitment is coordinated by interferon-gamma (IFNgamma). Neutrophil recruitment in response to PVM infection was diminished five-fold in IFNgamma receptor gene-deleted mice, although neutrophils from IFNgammaR -/- mice expressed transcripts for the CCL3 receptor, CCR1 and responded functionally to CCL3 ex vivo. Similarly, in the absence of PVM infection, CCL3 overexpression alone could not elicit neutrophil recruitment in the absence of IFNgamma. Interestingly, although supplemental IFNgamma restored neutrophil recruitment and resulted in a sustained weight loss among CCL3-overexpressing IFNgamma -/- mice, CCL3-mediated neutrophil recruitment alone did not result in the pulmonary edema or respiratory failure characteristic of severe viral infection, suggesting that CCL3 and IFN-gamma together are sufficient to promote neutrophil recruitment but not pathologic activation. CONCLUSION Our findings reveal a heretofore unrecognized hierarchical interaction between the IFNgamma and CCL3, which demonstrate that IFNgamma is crucial for CCL3-mediated neutrophil recruitment in vivo.
Collapse
MESH Headings
- Animals
- Cell Movement/immunology
- Chemokine CCL3/genetics
- Chemokine CCL3/immunology
- Chemokine CCL3/metabolism
- Gene Expression Profiling
- Interferon-gamma/genetics
- Interferon-gamma/immunology
- Interferon-gamma/metabolism
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Killer Cells, Natural/pathology
- Lung/immunology
- Lung/metabolism
- Lung/pathology
- Lung/virology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Murine pneumonia virus/immunology
- Murine pneumonia virus/pathogenicity
- Neutrophils/immunology
- Neutrophils/metabolism
- Neutrophils/pathology
- Pneumovirus Infections/genetics
- Pneumovirus Infections/immunology
- Pneumovirus Infections/physiopathology
- Pulmonary Edema
- Receptors, CCR1/genetics
- Receptors, CCR1/immunology
- Receptors, CCR1/metabolism
- Receptors, Interferon/genetics
- Receptors, Interferon/immunology
- Receptors, Interferon/metabolism
- Respiratory Insufficiency
- Signal Transduction/immunology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- T-Lymphocytes/pathology
- Interferon gamma Receptor
Collapse
Affiliation(s)
| | - Caroline M Percopo
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Kimberly D Dyer
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jiliang Gao
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Calman Prussin
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Barbara Foster
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
- Proteus Technologies, 133 National Business Parkway, Suite 150, Annapolis Junction, Maryland, 20701, USA
| | - Helene F Rosenberg
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | |
Collapse
|
66
|
Song W, Liu G, Bosworth CA, Walker JR, Megaw GA, Lazrak A, Abraham E, Sullender WM, Matalon S. Respiratory syncytial virus inhibits lung epithelial Na+ channels by up-regulating inducible nitric-oxide synthase. J Biol Chem 2009; 284:7294-306. [PMID: 19131335 PMCID: PMC2652346 DOI: 10.1074/jbc.m806816200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 01/06/2009] [Indexed: 12/13/2022] Open
Abstract
Respiratory syncytial virus (RSV) infection has been shown to reduce Na+-driven alveolar fluid clearance in BALB/c mice in vivo. To investigate the cellular mechanisms by which RSV inhibits amiloride-sensitive epithelial Na+ channels (ENaC), the main pathways through which Na+ ions enter lung epithelial cells, we infected human Clara-like lung (H441) cells with RSV that expresses green fluorescent protein (rRA2). 3-6 days later patch clamp recordings showed that infected cells (i.e. cells expressing green fluorescence; GFP+) had significantly lower whole-cell amiloride-sensitive currents and single channel activity (NPo) as compared with non-infected (GFP-), non-inoculated, or cells infected with UV-inactivated RSV. Both alpha and beta ENaC mRNA levels were significantly reduced in GFP+ cells as measured by real-time reverse transcription-PCR. Infection with RSV increased expression of the inducible nitric-oxide synthase (iNOS) and nitrite concentration in the culture medium; nuclear translocation of NF-kappaB p65 subunit and NF-kappaB activation were also up-regulated. iNOS up-regulation in GFP+ cells was prevented by knocking down IkappaB kinase gamma before infection. Furthermore, pretreatment of H441 cells with the specific iNOS inhibitor 1400W (1 microM) resulted in a doubling of the amiloride-sensitive Na+ current in GFP+ cells. Additionally, preincubation of H441 cells with A77-1726 (20 microM), a de novo UTP synthesis inhibitor, and 1400W completely reversed the RSV inhibition of amiloride-sensitive currents in GFP+ cells. Thus, both UTP- and iNOS-generated reactive species contribute to ENaC down-regulation in RSV-infected airway epithelial cells.
Collapse
Affiliation(s)
- Weifeng Song
- Department of Anesthesiology, Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama 35233, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
67
|
Kong MYF, Gaggar A, Li Y, Winkler M, Blalock JE, Clancy JP. Matrix metalloproteinase activity in pediatric acute lung injury. Int J Med Sci 2009; 6:9-17. [PMID: 19159011 PMCID: PMC2610341 DOI: 10.7150/ijms.6.9] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 12/15/2008] [Indexed: 01/11/2023] Open
Abstract
Pediatric Acute Lung Injury (ALI) is associated with a high mortality and morbidity, and dysregulation of matrix metalloproteinases (MMPs) may play an important role in the pathogenesis and evolution of ALI. Here we examined MMP expression and activity in pediatric ALI compared with controls. MMP-8, -9, and to a lesser extent, MMP-2, -3, -11 and -12 were identified at higher levels in lung secretions of pediatric ALI patients compared with controls. Tissue Inhibitor of Matrix metalloproteinase-1 (TIMP-1), a natural inhibitor of MMPs was detected in most ALI samples, but MMP-9:TIMP-1 ratios were high relative to controls. In subjects who remained intubated for >or=10 days, MMP-9 activity decreased, with > 80% found in the latent form. In contrast, almost all MMP-8 detected at later disease course was constitutively active. Discriminating MMP-9:TIMP-1 ratios were found in those who had a prolonged ALI course. These results identify a specific repertoire of MMP isoforms in the lung secretions of pediatric ALI patients, and demonstrate inverse changes in MMPs -8 and -9 with protracted disease.
Collapse
Affiliation(s)
- Michele Y F Kong
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL 35233, USA.
| | | | | | | | | | | |
Collapse
|
68
|
Bem RA, van Woensel JBM, Bos AP, Koski A, Farnand AW, Domachowske JB, Rosenberg HF, Martin TR, Matute-Bello G. Mechanical ventilation enhances lung inflammation and caspase activity in a model of mouse pneumovirus infection. Am J Physiol Lung Cell Mol Physiol 2008; 296:L46-56. [PMID: 18996903 DOI: 10.1152/ajplung.00467.2007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Severe infection with respiratory syncytial virus (RSV) in children can progress to respiratory distress and acute lung injury (ALI). Accumulating evidence suggests that mechanical ventilation (MV) is an important cofactor in the development of ALI by modulating the host immune responses to bacteria. This study investigates whether MV enhances the host response to pneumonia virus of mice (PVM), a mouse pneumovirus that has been used as a model for RSV infection in humans. BALB/c mice were inoculated intranasally with diluted clarified lung homogenates from mice infected with PVM strain J3666 or uninfected controls. Four days after inoculation, the mice were subjected to 4 h of MV (tidal volume, 10 ml/kg) or allowed to breathe spontaneously. When compared with that of mice inoculated with PVM only, the administration of MV to PVM-infected mice resulted in increased bronchoalveolar lavage fluid concentrations of the cytokines macrophage inflammatory protein (MIP)-2, MIP-1alpha (CCL3), and IL-6; increased alveolar-capillary permeability to high molecular weight proteins; and increased caspase-3 activity in lung homogenates. We conclude that MV enhances the activation of inflammatory and caspase cell death pathways in response to pneumovirus infection. We speculate that MV potentially contributes to the development of lung injury in patients with RSV infection.
Collapse
Affiliation(s)
- Reinout A Bem
- Pediatric Intensive Care Unit, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | | | | | | | | | | | | | | | | |
Collapse
|
69
|
Chen L, Song W, Davis IC, Shrestha K, Schwiebert E, Sullender WM, Matalon S. Inhibition of Na+ transport in lung epithelial cells by respiratory syncytial virus infection. Am J Respir Cell Mol Biol 2008; 40:588-600. [PMID: 18952569 DOI: 10.1165/rcmb.2008-0034oc] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We investigated the mechanisms by which respiratory syncytial virus (RSV) infection decreases vectorial Na+ transport across respiratory epithelial cells. Mouse tracheal epithelial (MTE) cells from either BALB/c or C57BL/6 mice and human airway H441 cells were grown on semipermeable supports under an air-liquid interface. Cells were infected with RSV-A2 and mounted in Ussing chambers for measurements of short-circuit currents (I(sc)). Infection with RSV for 24 hours (multiplicity of infection = 1) resulted in positive immunofluorescence for RSV antigen in less than 10% of MTE or H441 cells. In spite of the limited number of cells infected, RSV reduced both basal and amiloride-sensitive I(sc) in both MTE and H441 cells by approximately 50%, without causing a concomitant reduction in transepithelial resistance. Agents that increased intracellular cAMP (forskolin, cpt-CAMP, and IBMX) increased mainly Cl(-) secretion in MTE cells and Na+ absorption in H441 cells. RSV infection for 24 hours blunted both variables. In contrast, ouabain sensitive I(sc), measured across apically permeabilized H441 monolayers, remained unchanged. Western blot analysis of H441 cell lysates demonstrated reductions in alpha- but not gamma-ENaC subunit protein levels at 24 hours after RSV infection. The reduction in amiloride-sensitive I(sc) in H441 cells was prevented by pretreatment with inhibitors of de novo pyrimidine or purine synthesis (A77-1726 and 6-MP, respectively, 50 microM). Our results suggest that infection of both murine and human respiratory epithelial cells with RSV inhibits vectorial Na+ transport via nucleotide release. These findings are consistent with our previous studies showing reduced alveolar fluid clearance after RSV infection of BALB/c mice.
Collapse
Affiliation(s)
- Lan Chen
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL 35205-3703, USA
| | | | | | | | | | | | | |
Collapse
|
70
|
Nasal continuous positive airway pressure decreases respiratory muscles overload in young infants with severe acute viral bronchiolitis. Intensive Care Med 2008; 34:1865-72. [DOI: 10.1007/s00134-008-1201-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2008] [Accepted: 06/15/2008] [Indexed: 10/21/2022]
|
71
|
Berner ME, Hanquinet S, Rimensberger PC. High frequency oscillatory ventilation for respiratory failure due to RSV bronchiolitis. Intensive Care Med 2008; 34:1698-702. [PMID: 18500423 PMCID: PMC7095463 DOI: 10.1007/s00134-008-1151-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Accepted: 12/06/2007] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To describe the time course of high frequency oscillatory ventilation (HFOV) in respiratory syncytial virus (RSV) bronchiolitis. DESIGN Retrospective charts review. SETTING A tertiary paediatric intensive care unit. PATIENTS AND PARTICIPANTS Infants with respiratory failure due to RSV infection. INTERVENTION HFOV. MEASUREMENTS AND RESULTS Pattern of lung disease, ventilatory settings, blood gases, infant's vital parameters, sedation and analgesia during the periods of conventional mechanical ventilation (CMV, 6 infants), after initiation of HFOV (HFOVi, 9 infants), in the middle of its course (HFOVm), at the end (HFOVe) and after extubation (Post-Extub) were compared. All infants showed a predominant overexpanded lung pattern. Mean airway pressure was raised from a mean (SD) 12.5 (2.0) during CMV to 18.9 (2.7) cmH(2)O during HFOVi (P < 0.05), then decreased to 11.1(1.3) at HFOVe (P < 0.05). Mean FiO(2) was reduced from 0.68 (0.18) (CMV) to 0.59 (0.14) (HFOVi) then to 0.29 (0.06) (P < 0.05) at HFOVe and mean peak to peak pressure from 44.9 (12.4) cmH(2)O (HFOVi) to 21.1 (7.7) P < 0.05 (HFOVe) while mean (SD) PaCO(2) showed a trend to decrease from 72 (22) (CMV) to 47 (8) mmHg (HFVOe) and mean infants respiratory rate a trend to increase from 20 (11) (HFOVi) to 34 (14) (HFOVe) breaths/min. With usual doses of sedatives and opiates, no infant was paralysed and all were extubated to CPAP or supplemental oxygen after a mean of 120 h. CONCLUSION RSV induced respiratory failure with hypercapnia can be managed with HFOV using high mean airway pressure and large pressure swings while preserving spontaneous breathing.
Collapse
Affiliation(s)
- Michel E Berner
- Neonatology and Paediatric Intensive Care Service, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
| | | | | |
Collapse
|
72
|
Kneyber MCJ, Brouwers AGA, Caris JA, Chedamni S, Plötz FB. Acute respiratory distress syndrome: is it underrecognized in the pediatric intensive care unit? Intensive Care Med 2008; 34:751-4. [PMID: 18288473 PMCID: PMC7095351 DOI: 10.1007/s00134-008-1029-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 01/21/2008] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To describe the incidence of acute respiratory distress syndrome (ARDS) in mechanically ventilated children and to study whether ARDS is underrecognized in this patient population. DESIGN AND SETTING Retrospective observational study in a single-center bed pediatric intensive care unit serving two Dutch provinces. PATIENTS 533 mechanically ventilated children aged 0-16 years, all of whom met the North-American European Consensus Conference criteria for ARDS. MEASUREMENTS AND RESULTS Chest radiographs were screened for the novel presence of bilateral infiltrates, in patients with bilateral infiltrates the PaO2/FIO2 ratio was calculated on two separate consecutive measurements. If below 200, the patient was classified as having ARDS. Left ventricular dysfunction was ruled out by echocardiography. The incidence was calculated by obtaining the number of children aged 0-16 years in our region. For each patient it was noted whether the patient was currently considered to have ARDS. Forty-one patients (7.7%) met the criteria for ARDS, with an incidence of 2.2 per 100,000 per year. The mortality rate was 20.4%. Thirty patients (73.1%) had primary ARDS, mainly from viral lower respiratory tract disease. Only ten patients (24.4%) currently had ARDS. CONCLUSIONS The incidence of pediatric ARDS is low compared to that of adult ARDS, and further underestimated as most patients were diagnosed by their underlying diseases.
Collapse
Affiliation(s)
- Martin C J Kneyber
- Department of Pediatric Intensive Care, V.U. University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
| | | | | | | | | |
Collapse
|
73
|
Bem RA, Bos AP, Bots M, Wolbink AM, van Ham SM, Medema JP, Lutter R, van Woensel JBM. Activation of the granzyme pathway in children with severe respiratory syncytial virus infection. Pediatr Res 2008; 63:650-5. [PMID: 18317234 PMCID: PMC7100119 DOI: 10.1203/pdr.0b013e31816fdc32] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Granzymes (Grs), serine proteases present in granules of effector lymphocytes, are involved in several host immune responses, including the activation of cell death and inflammatory pathways. The main goal of this study was to determine whether the local cell-mediated Gr pathway is activated during severe respiratory syncytial virus (RSV) lower respiratory tract illness (LRTI) in children. Tracheal aspirates (TA) from 23 children with RSV-LRTI and 12 controls without pulmonary disease were analyzed for Gr A and B. Bronchoalveolar lavage fluid samples from seven children with RSV-LRTI were analyzed for cellular expression of GrB. Levels of GrA and GrB in TA were significantly increased in RSV patients compared with controls and both Grs showed preserved activity. Gr levels correlated with the total leukocyte counts and IL-8 levels in the airways at several time points. However, no correlation between Gr levels and release of caspase-cleaved cytokeratin-18 was found. There was evidence for marked expression of GrB by both CD8(+) and CD4(+) T cells and natural killer cells in the respiratory tract. These findings suggest activation of the cell-mediated Gr pathway during severe RSV-LRTI in children.
Collapse
Affiliation(s)
- Reinout A Bem
- Pediatric Intensive Care Unit, Academic Medical Center, Amsterdam, 1100 DD, The Netherlands.
| | - Albert P Bos
- Pediatric Intensive Care Unit, Academic Medical Center, Amsterdam, 1100 DD The Netherlands
| | - Michael Bots
- Laboratory for Experimental Oncology and Radiobiology, Academic Medical Center, Amsterdam, 1100 DD The Netherlands
| | - Angela M Wolbink
- Department of Immunopathology, Academic Medical Center, Amsterdam, 1066 CX The Netherlands
| | - S Marieke van Ham
- Department of Immunopathology, Academic Medical Center, Amsterdam, 1066 CX The Netherlands
| | - Jan Paul Medema
- Laboratory for Experimental Oncology and Radiobiology, Academic Medical Center, Amsterdam, 1100 DD The Netherlands
| | - Rene Lutter
- Departments of Pulmonology and Experimental Immunology, Academic Medical Center, Amsterdam, 1100 DD The Netherlands
| | - Job B M van Woensel
- Pediatric Intensive Care Unit, Academic Medical Center, Amsterdam, 1100 DD The Netherlands
| |
Collapse
|
74
|
Abstract
Among ventilated children, the incidence of acute lung injury (ALI) was 9%; of that latter group 80% developed the acute respiratory distress syndrome (ARDS). The population-based prevalence of pediatric ARDS was 5.5 cases/100.000 inhabitants. Underlying diseases in children were septic shock (34%), respiratory syncytial virus infections (16%), bacterial pneumonia (15%), near-drowning 9%, and others. Mortality ranged from 18% to 27% for ALI (including ALI-non ARDS and ARDS) and from 29% to 50% for ARDS. Mortality was only 3%-11% in children with ALI-non ARDS. As risk factors, oxygenation indices and multi-organ failure have been identified. New insights into the pathophysiology (for example the interplay between intraalveolar coagulation/fibrinolysis and inflammation and the genetic polymorphism for the angiotensin-converting enzyme) offer new therapeutic options. Lung protective mechanical ventilation with optimal lung recruitment is the mainstay of supportive therapy. New therapeutic modalities refer to corticosteroid and surfactant treatment. Well-designed follow up studies are needed.
Collapse
|
75
|
Kneyber MCJ, Plötz FB. Respiratory Syncytial Virus (RSV) in the Pediatric Intensive Care Unit. Intensive Care Med 2007. [DOI: 10.1007/978-0-387-49518-7_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
76
|
Almeida-Junior AA, da Silva MTN, Almeida CCB, Ribeiro JD. Relationship between physiologic deadspace/tidal volume ratio and gas exchange in infants with acute bronchiolitis on invasive mechanical ventilation. Pediatr Crit Care Med 2007; 8:372-7. [PMID: 17545938 DOI: 10.1097/01.pcc.0000269389.51189.a8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To evaluate the association between deadspace/tidal volume ratio (Vd/Vt) and gas exchange variables: Pao2, Paco2, Pao2/Fio2, arterial/alveolar oxygen tension ratio (Pao2/PAo2), alveolar-arterial oxygen tension difference/arterial oxygen tension ratio (P(A-a)o2/Pao2), carbon dioxide production (Vco2), ventilation index ([Paco2 x peak inspiratory pressure x mechanical respiratory rate]/1000), and oxygenation index ([mean airway pressure x Fio2 x 100]/Pao2), all measured at an early stage in children with obstructive acute respiratory failure. DESIGN Prospective, cross-sectional, observational study. SETTING Pediatric intensive care unit, university hospital. PATIENTS Twenty-nine infants with acute bronchiolitis, defined according to clinical and radiologic criteria. Children with chronic pulmonary disease, neuromuscular disease, congenital cardiopathies, or hemodynamic instability were excluded. INTERVENTIONS Measurements were made between 24 and 72 hrs of mechanical ventilation using volumetric capnography and arterial blood gas analysis. MEASUREMENTS AND MAIN RESULTS The following variables significantly correlated with Vd/Vt, calculated using Spearman's correlation coefficient (rs): Pao2 (rs = -0.63, p < .001), Pao2/Fio2 (rs = -0.56, p = .002), Pao2/PAo2 (rs = -0.46, p = .012), P(A-a)o2/Pao2 (rs = -0.46, p = .012), Paco2 (rs = 0.51, p = .005), Vco2 (rs = -0,62, p < .01), oxygenation index (rs = 0.48, p = .009), and ventilation index (rs = -0.53, p = .003). A statistically significant association was found between an increase in Vd/Vt and severity of lung injury, defined as Pao2/Fio2 <200 (p = .03, Mann-Whitney). CONCLUSIONS In the study population, Vd/Vt not only reflected ventilatory disorders, as is well recognized, but also was associated with disturbances of oxygenation. These results warrant further evaluation of the usefulness of serial measurement of Vd/Vt as a marker of disease severity in severe acute bronchiolitis and other causes of respiratory failure.
Collapse
Affiliation(s)
- Armando A Almeida-Junior
- Pediatric Intensive Care Unit, Center for Investigation in Pediatrics, State University of Campinas Medical School, Campinas, SP, Brazil.
| | | | | | | |
Collapse
|
77
|
Singh D, McCann KL, Imani F. MAPK and heat shock protein 27 activation are associated with respiratory syncytial virus induction of human bronchial epithelial monolayer disruption. Am J Physiol Lung Cell Mol Physiol 2007; 293:L436-45. [PMID: 17557802 PMCID: PMC2231338 DOI: 10.1152/ajplung.00097.2007] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Respiratory syncytial virus (RSV) is the major cause of bronchiolitis in infants, and a common feature of RSV infections is increased lung permeability. The accumulation of fluid in the infected lungs is caused by changes in the endothelial and epithelial membrane integrity. However, the exact mechanisms of viral-induced fluid extravasation remain unclear. Here, we report that infection of human epithelial cells with RSV results in significant epithelial membrane barrier disruption as assessed by a decrease in transepithelial electrical resistance (TEpR). This decrease in TEpR, which indicates changes in paracellular permeability, was mediated by marked cellular cytoskeletal rearrangement. Importantly, the decrease in TEpR was attenuated by using p38 MAPK inhibitors (SB-203580) but was partially affected by JNK inhibitor SP-600125. Interestingly, treatment of A549 cells with MEK1/2 inhibitor (U-0126) led to a decrease in TEpR in the absence of RSV infection. The changes in TEpR were concomitant with an increase in heat shock protein 27 (Hsp27) phosphorylation and with actin microfilament rearrangement. Thus our data suggest that p38 MAPK and Hsp27 are required for RSV induction of human epithelial membrane permeability.
Collapse
Affiliation(s)
- Divyendu Singh
- Laboratory of Respiratory Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | | | | |
Collapse
|
78
|
Davis IC, Xu A, Gao Z, Hickman-Davis JM, Factor P, Sullender WM, Matalon S. Respiratory syncytial virus induces insensitivity to beta-adrenergic agonists in mouse lung epithelium in vivo. Am J Physiol Lung Cell Mol Physiol 2007; 293:L281-9. [PMID: 17435077 PMCID: PMC2084466 DOI: 10.1152/ajplung.00458.2006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in infants and children worldwide. We wished to determine whether intratracheal administration of beta-agonists improved alveolar fluid clearance (AFC) across the distal respiratory epithelium of RSV-infected mice. Following intranasal infection with RSV strain A2, AFC was measured in anesthetized, ventilated BALB/c mice by instillation of 5% BSA into the dependent lung. We found that direct activation of protein kinase A by forskolin or 8-bromo-cAMP increased AFC at day 2 after infection with RSV. In contrast, short- and long-acting beta-agonists had no effect at either day 2 or day 4. Insensitivity to beta-agonists was not a result of elevated plasma catecholamines or lung epithelial cell beta-adrenergic receptor degradation. Instead, RSV-infected mice had significantly higher levels of phosphorylated PKCzeta in the membrane fractions of their lung epithelial cells. In addition, insensitivity to beta-agonists was mediated in a paracrine fashion by KC (the murine homolog of CXCL8) and reversed by inhibition of either PKCzeta or G protein-coupled receptor kinase 2 (GRK2). These results indicate that insufficient response to beta-agonists in RSV may be caused, at least in part, by impaired beta-adrenergic receptor signaling, as a consequence of GRK2-mediated uncoupling of beta-adrenergic receptors from adenylyl cyclase.
Collapse
Affiliation(s)
- Ian C. Davis
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Anna Xu
- Department of Pulmonary Medicine, Columbia University Medical Center, New York, NY, USA
| | - Zhiqian Gao
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Judy M. Hickman-Davis
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Phillip Factor
- Department of Pulmonary Medicine, Columbia University Medical Center, New York, NY, USA
| | - Wayne M. Sullender
- Department of Pediatrics & Microbiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Sadis Matalon
- Department of Anesthesiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
- Department of Physiology & Biophysics, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| |
Collapse
|
79
|
Bem RA, Bos AP, Matute-Bello G, van Tuyl M, van Woensel JBM. Lung epithelial cell apoptosis during acute lung injury in infancy. Pediatr Crit Care Med 2007; 8:132-7. [PMID: 17273113 DOI: 10.1097/01.pcc.0000257207.02408.67] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
CONTEXT Apoptosis of lung epithelial cells is implicated in the pathogenesis of acute lung injury. Most research on this subject has focused on adults. Very little is known about a potential interaction of this process with lung development in children. OBJECTIVE To summarize the current literature on lung epithelial cell apoptosis and common causes of acute lung injury in infants and young children and to identify new areas of research. DESIGN A Medline-based literature search. RESULTS AND CONCLUSIONS Few studies have focused on lung epithelial cell apoptosis during common causes of acute lung injury in children. Nevertheless, the limited literature suggests that this may be an important mechanism during respiratory distress syndrome of infants and viral respiratory tract infection. Apoptosis is an essential process during lung development and maturation. Insufficient attention has been paid to potential consequences of this for the short- and long-term outcomes of acute lung injury.
Collapse
Affiliation(s)
- Reinout A Bem
- Pediatric Intensive Care Unit, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | | | | | | | | |
Collapse
|
80
|
Affiliation(s)
- Jürg Hammer
- Division of Intensive Care and Pulmonology, University Children's Hospital Basel, Switzerland.
| |
Collapse
|
81
|
Rodriguez Martinez CE, Guzman MC, Castillo JM, Sossa MP, Ojeda P. Evaluation of clinical criteria for the acute respiratory distress syndrome in pediatric patients. Pediatr Crit Care Med 2006; 7:335-9. [PMID: 16738504 DOI: 10.1097/01.pcc.0000224993.03233.63] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The primary goal of this study was to evaluate the validity of the North American-European Consensus Committee (NAECC) definition for acute respiratory distress syndrome (ARDS) in pediatric patients. A secondary aim was to evaluate the threshold value for the PaO2/FiO2 ratio, used to determine which pediatric patients have ARDS. DESIGN Retrospective cohort study. SETTING Pediatric intensive care unit. PATIENTS Pediatric intensive care unit patients who required mechanical ventilation, died, and underwent autopsy between January 1, 1996, and December 31, 2002 (n = 34). INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Clinical and chest radiograph information was collected retrospectively through chart review using a standardized data collection tool. Data included the criteria specified in the NAECC definition of ARDS and demographic information. We calculated the sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio of clinical diagnosis of ARDS compared with a pathologic diagnosis. The threshold value of PaO2/FiO2 was identified by plotting receiver operating characteristics curves and comparing the areas under the curves. The NAECC definition yielded a sensitivity of 80.7% (95% confidence interval 60-92%), specificity of 71.4% (95% confidence interval 30-95), positive predictive value of 91.3% (95% confidence interval 70-98), negative predictive value of 50.0% (95% confidence interval 20-78), and likelihood ratio of 2.82. A PaO2/FiO2 <150 had a slightly higher (but not significantly different) specificity for ARDS than a value >200 (71% vs. 86%, p = .15) without changing sensitivity. CONCLUSIONS Our study suggests the need for further research with larger number of children to identify an optimal Pao2/Fio2 threshold for identifying ARDS in this population.
Collapse
Affiliation(s)
- Carlos E Rodriguez Martinez
- Department of Pulmonary and Pediatric Critical Care Medicine, Hospital Santa Clara, Clinica Colsanitas, Clinica Infantil Colsubsidio, Bogota, Colombia
| | | | | | | | | |
Collapse
|
82
|
Abstract
Pediatric acute respiratory distress syndrome (ARDS) is a severe lung injury caused by pneumonia, sepsis, and trauma. ARDS results from inflammation and pulmonary capillary leak causing major changes in lung architecture and function. It has a low incidence, but its severity and duration cause major morbidity, mortality, and use of resources. Any organism can cause ARDS. Susceptible populations develop the syndrome more often and have worse outcomes. Aggressive diagnosis and intensive treatment are essential to good outcomes in ARDS caused by infection. The prognosis for survival is good, but morbidity after the syndrome is a major burden.
Collapse
|
83
|
Openshaw PJM, Tregoning JS. Immune responses and disease enhancement during respiratory syncytial virus infection. Clin Microbiol Rev 2005; 18:541-55. [PMID: 16020689 PMCID: PMC1195968 DOI: 10.1128/cmr.18.3.541-555.2005] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Respiratory syncytial virus (RSV) is one of the commonest and most troublesome viruses of infancy. It causes most cases of bronchiolitis, which is associated with wheezing in later childhood. In primary infection, the peak of disease typically coincides with the development of specific T- and B-cell responses, which seem, in large part, to be responsible for disease. Animal models clearly show that a range of immune responses can enhance disease severity, particularly after vaccination with formalin-inactivated RSV. Prior immune sensitization leads to exuberant chemokine production, an excessive cellular influx, and an overabundance of cytokines during RSV challenge. Under different circumstances, specific mediators and T-cell subsets and antibody-antigen immune complex deposition are incriminated as major factors in disease. Animal models of immune enhancement permit a deep understanding of the role of specific immune responses in RSV disease, assist in vaccine design, and indicate which immunomodulatory therapy might be beneficial to children with bronchiolitis.
Collapse
Affiliation(s)
- Peter J M Openshaw
- Department of Respiratory Medicine, National Heart and Lung and Wright Fleming Institutes, Faculty of Medicine, Imperial College London, Paddington, London W2 1PG, United Kingdom.
| | | |
Collapse
|
84
|
Bouchut JC, Mallet E. Weaning directly from high frequency oscillatory ventilation: the 'open lung' strategy expanded to weaning? Paediatr Anaesth 2004; 14:1030-1. [PMID: 15601356 DOI: 10.1111/j.1460-9592.2004.01449.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
85
|
Broughton S, Greenough A. Effectiveness of drug therapies to treat or prevent respiratory syncytial virus infection-related morbidity. Expert Opin Pharmacother 2003; 4:1801-8. [PMID: 14521489 DOI: 10.1517/14656566.4.10.1801] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Respiratory syncytial virus (RSV) infection causes a huge burden to the health service, as it results in a large number of in-patient days each year and increases the risk of asthma in childhood. In the acute phase, therapy is supportive as bronchodilators and corticosteroids have resulted, at best, only in short-term benefits; promising treatments for ventilated patients, such as exogenous surfactant, require further testing. Passive immunoprophylaxis reduces hospital admission in high risk groups. In the prevention of chronic respiratory morbidity following RSV infection, however, studies are needed to determine whether immunoprophylaxis will have a useful role and to identify which drug treatment will be most cost-effective.
Collapse
Affiliation(s)
- Simon Broughton
- Department of Child Health, Guy's King's and St Thomas' Medical School, 4th Floor Golden Jubilee Wing, King's College Hospital, London SE5 9RS, UK
| | | |
Collapse
|
86
|
Hammer J, Patel N, Newth CJL. Effect of forced deflation maneuvers upon measurements of respiratory mechanics in ventilated infants. Intensive Care Med 2003; 29:2004-8. [PMID: 12897998 DOI: 10.1007/s00134-003-1895-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2002] [Accepted: 06/03/2003] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To determine the effect of forced deflation maneuvers on respiratory mechanics and to assess the reproducibility of such measurements in intubated infants with lung disease. DESIGN AND SETTING Prospective study in the pediatric intensive care unit of a university children's hospital. PATIENTS Ten clinically stable infants requiring mechanically assisted ventilation for acute pulmonary disease, mean age 5.9 months (1-18), mean weight 5.8 kg (3.2-13). INTERVENTIONS Two sets of measurements of compliance (Crs) and resistance (Rrs) were obtained at 20-min intervals both before and after +40/-40 cmH(2)O forced deflation maneuvers. Forced deflation measurements were repeated at the end of the study. RESULTS . Forced deflation caused a significant increase in Crs from 0.53+/-0.09 and 0.58+/-0.11 ml/cmH(2)O/kg to 0.71+/-0.11 and 0.68+/-0.11 ml/cmH(2)O/kg. Rrs measurements did not differ. The low coefficients of variation for repeated measures of the baseline measurements (Crs 4.2+/-0.5%, Rrs 7.1+/-0.8%, for forced vital capacity 8.6+/-2.5%, maximum expiratory flows at 25% vital capacity 16.0%+/-3.3%) confirmed the good reproducibility during stable conditions. CONCLUSIONS Inflation and deflation maneuvers affect subsequent measurements of respiratory system compliance but not measurements of maximum expiratory flow-volume relationships in intubated infants, probably through recruitment of lung volume. Careful interpretation and planning of the sequence of infant pulmonary function testing is necessary to reassure that changes are not related to short-term alterations in volume history.
Collapse
Affiliation(s)
- Jürg Hammer
- Division of Pediatric Intensive Care and Pulmonology, University Children's Hospital, Römergasse 8, 4005, Basel, Switzerland.
| | | | | |
Collapse
|
87
|
Moynihan JA, Brown L, Sehra R, Checchia PA. Cardiac troponin i as a predictor of respiratory failure in children hospitalized with respiratory syncytial virus (RSV) infections: a pilot study. Am J Emerg Med 2003; 21:479-82. [PMID: 14574656 DOI: 10.1016/s0735-6757(03)00163-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
This pilot study was performed to assess the use of cardiac troponin I to predict respiratory failure in children admitted to the hospital with respiratory syncytial virus (RSV) infections. We enrolled a prospective convenience sample of children under 5 years of age who were admitted to our university-based, tertiary care children's hospital from December 1, 2000, to February 1, 2002, with RSV infections. A cardiac troponin I was drawn at admission. We assessed the test characteristics for positive cardiac troponin I (defined as >0.3 ng/mL, the manufacturer's upper limit of normal) in correctly identifying children who had respiratory failure as evidenced by the need for endotracheal intubation. Twenty-five children from 9 days to 38 months of age were included. Ten children had a positive cardiac troponin I and 3 of these children had respiratory failure. A positive cardiac troponin I demonstrated a sensitivity of 100%, specificity 68%, positive predictive value of 30%, negative predictive value of 100%, and accuracy of 72%. The area under the receiver operating characteristic curve was 0.939 (95% confidence interval, 0.820-1.0), suggesting a high degree of discriminatory power in selecting children with respiratory failure. A sample size calculation revealed that a follow-up study of 359 patients is needed before the clinical use of cardiac troponin I for this purpose.
Collapse
Affiliation(s)
- James A Moynihan
- Department of Emergency Medicine, Division of Pediatric Emergency Medicine, Loma Linda University Medical Center and Children's Hospital, Loma Linda, California 92354, USA.
| | | | | | | |
Collapse
|
88
|
Abstract
This paper provides an update and critical review of available data on the treatment of acute viral bronchiolitis in previously healthy infants, with special focus on new or promising therapies. The main potential benefits of medical assistance in these patients reside in the careful monitoring of their clinical status, the maintenance of adequate hydration and oxygenation, the preservation of the airway opened and cleared of secretions and the option to perform parental education. There is no convincing evidence that any other form of therapy will reliably provide beneficial effects in infants with bronchiolitis and currently, any treatment beyond supportive care should be prescribed on a case-by-case basis with watchful appraisal of its effects. Therapies such as ribavirin, IFN, vitamin A, antibiotics, mist therapy or anticholinergics, have not demonstrated any measurable clinical effect. Several studies and meta-analyses with beta(2)-agonists and corticosteroids have failed to show any benefit of significant extent, however, physicians keep favouring their use. Presently, adrenaline has received rather consistent support from clinical trials but it is not yet widely prescribed. There are other therapeutic strategies, for instance, heliox, hypertonic saline, noninvasive ventilation, physical therapy techniques, thickened feeds or palivizumab that have shown promising potential benefits, but evidence supporting its use is still limited and further studies should be warranted. In the meantime, infants with acute viral bronchiolitis should be treated following evidence-based clinical practice guidelines, keeping the patient central in the process and being sensitive to social, cultural and familiar influences on their treatment strategy.
Collapse
Affiliation(s)
- Federico Martinón-Torres
- Department of Paediatrics, Universidad de Santiago de Compostela, Hospital Clínico Universitario de Santiago de Compostela, c/A choupana sn, 15706 Santiago de Compostela, Spain.
| |
Collapse
|
89
|
Godfrey S, Bar-Yishay E, Avital A, Springer C. What is the role of tests of lung function in the management of infants with lung disease? Pediatr Pulmonol 2003; 36:1-9. [PMID: 12772216 DOI: 10.1002/ppul.10282] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This review considers whether there is a role for lung function tests in the clinical management of infants with lung disease. The purpose of testing lung function in older subjects, the tests available for infants, and the practical problems of testing lung function in infants are considered. After reviewing all the facts, we suggest that there are four situations in which lung function testing should be recommended for infants, as follows: (1) the infant who presents with unexplained tachypnea, hypoxia, cough, or respiratory distress in whom a definitive diagnosis is not apparent from physical examination and other, less difficult investigations; (2) the infant with severe, continuous, chronic obstructive lung disease who does not respond to an adequate clinical trial of combined corticosteroid and bronchodilator therapy; (3) the infant with known respiratory disease of uncertain severity in whom there is need to justify management decisions; and (4) research and development. A review of 62 recent publications to determine how lung function tests are being used at the present time showed that they are being used overwhelmingly for research. The role of lung function testing in the clinical management of infants has not been established, and research is needed to clarify this situation. We suggest that such studies should explore the role of lung function tests in infants with specific symptoms, signs, or diagnoses, taking into account information from other types of investigation and the cost/benefit/risk ratios.
Collapse
Affiliation(s)
- S Godfrey
- Institute of Pulmonology, Hadassah University Hospital, Jerusalem, Israel.
| | | | | | | |
Collapse
|
90
|
Randolph AG, Meert KL, O'Neil ME, Hanson JH, Luckett PM, Arnold JH, Gedeit RG, Cox PN, Roberts JS, Venkataraman ST, Forbes PW, Cheifetz IM. The feasibility of conducting clinical trials in infants and children with acute respiratory failure. Am J Respir Crit Care Med 2003; 167:1334-40. [PMID: 12615617 DOI: 10.1164/rccm.200210-1175oc] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Designing robust clinical trials in critically ill, mechanically ventilated children requires an understanding of the epidemiology and course of pediatric respiratory failure. As part of a clinical trial, we screened all mechanically ventilated children in nine large pediatric intensive care units (ICUs) across North America for 6 consecutive months. Of 6,403 total ICU admissions, 1,096 (17.1%) required mechanical ventilator support for a minimum of 24 hours. Of these, 701 (64%) met one or more exclusion criteria for trial enrollment. Common reasons for exclusion were upper airway obstruction (13.5%) and cyanotic congenital heart disease (11.5%). Life support interventions were restricted for 9.7% of patients, and 5.5% were chronically ventilator dependent. In the patients who were eligible for respiratory failure studies, 62.4% had an acute primary diagnosis of pulmonary disease, 14.2% neurologic disease, and 8.9% cardiac disease. Chronic underlying conditions were present in 43.2% of the patients. The most common acute diagnosis was bronchiolitis in infants (43.6%) and pneumonia in children 1 year old and older (24.5%). Mortality was rare (1.6%), and the median duration of ventilation was 7 days. The design of clinical trials in critically ill children is feasible but must account for the diverse population, infrequent mortality, and short duration of mechanical ventilation.
Collapse
|
91
|
van Woensel JBM, van Aalderen WMC, de Weerd W, Jansen NJG, van Gestel JPJ, Markhorst DG, van Vught AJ, Bos AP, Kimpen JLL. Dexamethasone for treatment of patients mechanically ventilated for lower respiratory tract infection caused by respiratory syncytial virus. Thorax 2003; 58:383-7. [PMID: 12728156 PMCID: PMC1746666 DOI: 10.1136/thorax.58.5.383] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND A study was undertaken to evaluate the efficacy of dexamethasone in patients mechanically ventilated for lower respiratory infection caused by respiratory syncytial virus (RSV-LRTI). METHODS In a multicentre randomised controlled trial patients were randomised to receive either intravenous dexamethasone (0.15 mg/kg 6 hourly for 48 hours) or placebo. End points were the duration of mechanical ventilation, length of stay (LOS) in the pediatric intensive care unit (PICU) and in hospital, and the duration of supplemental oxygen administration. RESULTS Thirty seven patients received dexamethasone and 45 received placebo. There was no significant difference in any of the end points between the two groups. In a post hoc analysis patients were stratified into those with mild gas exchange anomalies (PaO(2)/FiO(2) >200 mm Hg and/or mean airway pressure </= 10 cm H(2)O, bronchiolitis group) and those with severe gas exchange anomalies (PaO(2)/FiO(2) </=200 mm Hg and mean airway pressure >10 cm H(2)O, pneumonia group). In the 39 patients with bronchiolitis the duration of mechanical ventilation was 4.3 days shorter in the dexamethasone group than in the placebo group (4.9 v 9.2 days, 95% CI -7.8 to -0.8, p=0.02) and the duration of supplemental oxygen was 3.6 days shorter (7.7 v 11.3 days, 95% CI -8.0 to -0.1, p=0.048). No differences in end points were found in the pneumonia group. CONCLUSIONS Dexamethasone had no beneficial effect in patients mechanically ventilated for RSV-LRTI but was found to have a beneficial effect in patients with bronchiolitis.
Collapse
Affiliation(s)
- J B M van Woensel
- Emma Children's Hospital Academic Medical Center, Amsterdam, The Netherlands.
| | | | | | | | | | | | | | | | | |
Collapse
|
92
|
Luchetti M, Ferrero F, Gallini C, Natale A, Pigna A, Tortorolo L, Marraro G. Multicenter, randomized, controlled study of porcine surfactant in severe respiratory syncytial virus-induced respiratory failure. Pediatr Crit Care Med 2002; 3:261-268. [PMID: 12780967 DOI: 10.1097/00130478-200207000-00011] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE: Recently, natural exogenous surfactant replacement has been used in experimental models and clinical trials for the treatment of severe respiratory syncytial virus (RSV) disease. The present study was aimed at verifying this hypothesis and confirming the results of our previous pilot study by assessing the effect of surfactant treatment in mechanically ventilated infants with severe RSV-induced respiratory failure. DESIGN: Multicenter, randomized, controlled study. SETTING: Six pediatric intensive care units staffed by full-time intensive care physicians. PATIENTS: A total of 40 infants (20 treated and 20 controls) with RSV-induced respiratory failure requiring conventional mechanical ventilation (CMV) were randomly assigned to either exogenous surfactant (treated group) or conventional treatment (control group) over a 1-yr period. INTERVENTIONS: Fifty milligrams per kilogram of body weight of porcine-derived natural surfactant (Curosurf) was administered. The drug was instilled by means of a syringe attached to a small suction catheter inserted into the endotracheal tube down to its tip, momentarily disconnecting the patient from CMV. Main Outcome Measures: The assessment consisted of the following outcome variables: duration of CMV, length of intensive care unit stay, gas exchange, respiratory mechanics, re-treatment need, complications, and mortality. RESULTS: The two groups were similar with regard to demographics, Pediatric Risk of Mortality scores, and baseline Pao(2)/Fio(2), Paco(2), and ventilator settings. A marked increase in Pao(2)/Fio(2) and decrease in Paco(2) were observed in the treated group after surfactant administration. Hemodynamic parameters remained unchanged throughout the study period. Peak inspiratory pressure and static compliance were similar at baseline in the two groups. A decrease in peak inspiratory pressure and increase in static compliance were observed in the treated group after surfactant administration. Among surfactant-treated patients, 15 received the treatment within 24 hrs of admission, whereas the remainder (five patients) were treated later. Among children who were treated later, three needed an additional dose of surfactant. None of the children treated within 24 hrs needed an additional dose. Duration of CMV and length of stay in the intensive care unit were significantly shorter in the treated group (4.6 +/- 0.8 and 6.4 +/- 0.9 days, respectively) compared with the control group (5.8 +/- 0.7 and 8.2 +/- 1.1 days, respectively) (p <.0001). No relevant complications were observed, and all the infants survived. CONCLUSIONS: Consistent with our previous study and others, this study shows that surfactant therapy improves gas exchange and respiratory mechanics and shortens CMV and intensive care unit stay in infants with severe RSV-induced respiratory failure.
Collapse
Affiliation(s)
- Marco Luchetti
- Pediatric Intensive Care Units at "Fatebenefratelli" and Ophthalmiatric Hospital (ML, GM), Milano, Italy; "Regina Margherita" Hospital, Torino, Italy; "S.Antonio e Biagio" Hospital, Alessandria, Italy; "Santobono" Children's Hospital, Napoli, Italy; "S. Orsola Malpighi" Hospital, Bologna, Italy; and "Gemelli" Hospital, Roma, Italy
| | | | | | | | | | | | | |
Collapse
|
93
|
Abstract
Respiratory syncytial virus is the leading cause of hospital admission for lower respiratory tract infection in young children and appears to be responsible for a significant burden of disease in adults, particularly the elderly and the immunocompromised. In this review, we describe the epidemiology, diagnosis and clinical manifestations of infection attributed to this virus. We also consider current therapeutic and prophylactic options and appraise strategies for vaccination that are in clinical trials.
Collapse
Affiliation(s)
- C L Collins
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Level 4, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | | |
Collapse
|
94
|
Leclerc F. Is there a place for exogenous surfactant in mechanically ventilated infants with severe respiratory syncytial virus infection? Pediatr Crit Care Med 2002; 3:319-20. [PMID: 12813229 DOI: 10.1097/00130478-200207000-00029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
95
|
|
96
|
Leclerc F, Scalfaro P, Noizet O, Thumerelle C, Dorkenoo A, Fourier C. Mechanical ventilatory support in infants with respiratory syncytial virus infection. Pediatr Crit Care Med 2001; 2:197-204. [PMID: 12793941 DOI: 10.1097/00130478-200107000-00002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE: To present a review of current knowledge of the use of mechanical ventilatory support in the management of infants with respiratory failure secondary to infection with respiratory syncytial virus (RSV). DATA SOURCES: MEDLINE and manual search for case reports and clinical trials that address management strategies for respiratory support of infants with RSV infection. Data Extraction and Synthesis: Critical appraisal of reported epidemiologic and clinical data regarding risk factors, pathophysiology, and efficacy of respiratory therapy. There is an increasing number of hospital admissions for RSV infection with a variable proportion of infants who need mechanical ventilatory support. The mortality rate is estimated to be <1% in infants without preexisting respiratory or cardiac disorders vs. <5% in those with preexisting respiratory or cardiac disorders. Optimal ventilator settings need to be refined according to the dominant obstructive or restrictive pattern with the aim to avoid barovolutrauma. The role of noninvasive ventilation and additional therapies (heliox, beta(2) agonists, surfactant) is not conclusively established. The indications for high-frequency oscillatory ventilation with the possible adjunction of inhaled nitric oxide deserve further study. Extracorporeal membrane oxygenation plays a minor role in severe cases that are refractory to conventional treatment. CONCLUSIONS: Conventional ventilation strategies are usually adequate for treating infants with severe RSV infection. Particular attention must be paid to the dominant pathophysiologic mechanism in a given condition. Prospective trials are needed to validate alternative therapeutic options and to improve the outcome of the rare but most severe cases that are difficult to control.
Collapse
Affiliation(s)
- F. Leclerc
- Service de Réanimation Pédiatrique, Hôpital Jeanne de Flandre, Lille-Cedex, France (Drs. Leclerc, Noizet, Thumerelle, Fourier, and Dorkenoo) and Soins intensifs médico-chirurgicaux de Pédiatrie, Département de Pédiatrie, Lausanne, Switzerland (Dr. Scalfaro)
| | | | | | | | | | | |
Collapse
|
97
|
Numa AH, Williams GD, Dakin CJ. The effect of nebulized epinephrine on respiratory mechanics and gas exchange in bronchiolitis. Am J Respir Crit Care Med 2001; 164:86-91. [PMID: 11435244 DOI: 10.1164/ajrccm.164.1.2008090] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Nebulized epinephrine has been advocated as a treatment for airway obstruction in infants with bronchiolitis; however, its effect on respiratory mechanics and gas exchange has been poorly documented to date. We performed a preinterventional and postinterventional study with primary outcome measures of mechanics (measured by single-breath occlusion passive deflation) and oxygenation and ventilation indices in order to measure the effects of nebulized epinephrine in infants requiring mechanical ventilation for RSV-positive bronchiolitis. A two-compartment model was used to describe respiratory mechanics in patients with nonlinear flow-volume curves. Nebulized epinephrine (0.5 mg/kg) was administered to 15 patients (median age, 0.19 yr; weight, 4.4 kg). Resistance decreased significantly in slow and fast compartments in 87 and 70% of patients, respectively. Median resistance in the slow compartment decreased from 0.427 to 0.198 cm H2O/ml/s (p = 0.0015) and in the fast compartment from 0.167 to 0.116 cm H2O/ ml/s (p = 0.018). Compliance, oxygenation index, and ventilation index were not significantly changed after administration of epinephrine. We conclude that nebulized epinephrine substantially improves respiratory system resistance but not oxygenation or ventilation indices. This may be because of the effects of epinephrine on oxygen consumption or ventilation-perfusion matching.
Collapse
Affiliation(s)
- A H Numa
- Department of Intensive Care, Sydney Children's Hospital, Sydney, Australia.
| | | | | |
Collapse
|
98
|
Greenough A. Recent advances in the management and prophylaxis of respiratory syncytial virus infection. ACTA PAEDIATRICA (OSLO, NORWAY : 1992). SUPPLEMENT 2001; 90:11-4. [PMID: 11332948 DOI: 10.1111/j.1651-2227.2001.tb01621.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Respiratory syncytial virus (RSV) infection is an important cause of morbidity, particularly in prematurely born infants who have had chronic lung disease. Current therapy is essentially supportive. Overall, the results of randomized trials do not support the use of bronchodilators, corticosteroids or Ribavirin. Nitric oxide and exogenous surfactant may improve the respiratory status of those infants who require ventilatory support. Nosocomial infection can be reduced by appropriate handwashing. There is no safe and effective vaccine for use in infants. Immunoprophylaxis reduces hospitalization and requirement for intensive care. Palivizumab, a humanized monoclonal antibody, is preferred to RSV immune globulin as the immunoprophylactic agent. Immunoprophylaxis should be reserved for infants at highest risk of severe respiratory syncytial virus infection, if this strategy is to be used most cost-effectively.
Collapse
Affiliation(s)
- A Greenough
- Department of Child Health, Guy's, King's and St Thomas' School of Medicine, King's College Hospital, London, UK.
| |
Collapse
|
99
|
Abstract
Acute respiratory distress syndrome (ARDS) is a clinically defined entity describing the severity of diffuse alveolar injury caused by direct or indirect injury to the lung. Pathophysiology, clinical course and outcome of ARDS depend on the underlying cause, the severity of the disease and co-morbidities. Pulmonary function tests show restrictive lung disease, which is characterised by a reduction in lung compliance and functional residual capacity, resulting in marked ventilation-perfusion inequality. Current ventilator strategies aim to minimise ventilator-induced lung injury by targeting mechanical ventilation between the lower and upper inflection point of the pressure volume curve. This includes recruitment manoeuvres and the use of high PEEP to open the atelectatic lung and the use of permissive hypercapnia and the limitation of peak inspiratory pressure below 35 cm H2O to avoid overinflation. The clinical benefit of newer modes of ventilatory support such as inverse ratio ventilation, high frequency oscillatory ventilation, surfactant replacement, prone positioning and inhaled nitric oxide has yet to be determined in children.
Collapse
Affiliation(s)
- J Hammer
- Division of Paediatric Intensive Care and Pulmonology, University Children's Hospital Basel, Postfach, Basel, 4005, Switzerland
| |
Collapse
|
100
|
Abstract
Mortality rates in ARDS are improving, with several recent studies reporting mortality in the order of 20-40% rather than the early descriptions of this disease in which a mortality of 40-60% or higher was frequently cited. The ability to accurately predict outcomes plays an important role in the assessment of the impact of new therapies. Traditionally clinicians have relied on simple respiratory indices to assess mortality risk; however, the predictive ability of such indices, particularly early in the course of the disease, is somewhat limited. Adult data suggest that improved prediction not only of the outcome of established ARDS but also of the development of ARDS in at-risk patients may be obtained by measuring the concentrations of inflammatory mediators and/or surfactant-associated proteins in plasma or bronchoalveolar lavage samples. A bewildering array of therapies for ARDS is available; in many cases the benefits are uncertain. Treatments of proven value in adults include using PEEP beyond the lower inflection point of the pressure-volume curve and limiting tidal volumes to 6 ml/kg. Nitric oxide appears to offer no benefit to outcomes, although it does improve oxygenation in some patients. Surfactant is still undergoing assessment in randomised controlled trials; however, the use of aerosolised surfactant has been recently shown to be ineffective in adult patients with ARDS. Perfluorocarbon-assisted gas exchange (PAGE) or partial liquid ventilation is similarly still being assessed in randomised controlled trials in adults.
Collapse
Affiliation(s)
- A H Numa
- Intensive Care Unit, Sydney Children's Hospital, High Street, Randwick, NSW 2031, Australia
| |
Collapse
|