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Slobod D, Damia A, Leali M, Spinelli E, Mauri T. Pathophysiology and Clinical Meaning of Ventilation-Perfusion Mismatch in the Acute Respiratory Distress Syndrome. BIOLOGY 2022; 12:biology12010067. [PMID: 36671759 PMCID: PMC9855693 DOI: 10.3390/biology12010067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/20/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023]
Abstract
Acute respiratory distress syndrome (ARDS) remains an important clinical challenge with a mortality rate of 35-45%. It is being increasingly demonstrated that the improvement of outcomes requires a tailored, individualized approach to therapy, guided by a detailed understanding of each patient's pathophysiology. In patients with ARDS, disturbances in the physiological matching of alveolar ventilation (V) and pulmonary perfusion (Q) (V/Q mismatch) are a hallmark derangement. The perfusion of collapsed or consolidated lung units gives rise to intrapulmonary shunting and arterial hypoxemia, whereas the ventilation of non-perfused lung zones increases physiological dead-space, which potentially necessitates increased ventilation to avoid hypercapnia. Beyond its impact on gas exchange, V/Q mismatch is a predictor of adverse outcomes in patients with ARDS; more recently, its role in ventilation-induced lung injury and worsening lung edema has been described. Innovations in bedside imaging technologies such as electrical impedance tomography readily allow clinicians to determine the regional distributions of V and Q, as well as the adequacy of their matching, providing new insights into the phenotyping, prognostication, and clinical management of patients with ARDS. The purpose of this review is to discuss the pathophysiology, identification, consequences, and treatment of V/Q mismatch in the setting of ARDS, employing experimental data from clinical and preclinical studies as support.
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Affiliation(s)
- Douglas Slobod
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
- Department of Critical Care Medicine, McGill University, Montreal, QC H3A 3R1, Canada
| | - Anna Damia
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
| | - Marco Leali
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
| | - Elena Spinelli
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Tommaso Mauri
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
- Correspondence:
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Marongiu I, Spinelli E, Scotti E, Mazzucco A, Wang YM, Manesso L, Colussi G, Biancolilli O, Battistin M, Langer T, Roma F, Lopez G, Lonati C, Vaira V, Rosso L, Ferrero S, Gatti S, Zanella A, Pesenti A, Mauri T. Addition of 5% CO 2 to Inspiratory Gas Prevents Lung Injury in an Experimental Model of Pulmonary Artery Ligation. Am J Respir Crit Care Med 2021; 204:933-942. [PMID: 34252009 PMCID: PMC8534619 DOI: 10.1164/rccm.202101-0122oc] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 07/12/2021] [Indexed: 11/19/2022] Open
Abstract
Rationale: Unilateral ligation of the pulmonary artery may induce lung injury through multiple mechanisms, which might be dampened by inhaled CO2. Objectives: This study aims to characterize bilateral lung injury owing to unilateral ligation of the pulmonary artery in healthy swine undergoing controlled mechanical ventilation and its prevention by 5% CO2 inhalation and to investigate relevant pathophysiological mechanisms. Methods: Sixteen healthy pigs were allocated to surgical ligation of the left pulmonary artery (ligation group), seven to surgical ligation of the left pulmonary artery and inhalation of 5% CO2 (ligation + FiCO2 5%), and six to no intervention (no ligation). Then, all animals received mechanical ventilation with Vt 10 ml/kg, positive end-expiratory pressure 5 cm H2O, respiratory rate 25 breaths/min, and FiO2 50% (±FiCO2 5%) for 48 hours or until development of severe lung injury. Measurements and Main Results: Histological, physiological, and quantitative computed tomography scan data were compared between groups to characterize lung injury. Electrical impedance tomography and immunohistochemistry analysis were performed in a subset of animals to explore mechanisms of injury. Animals from the ligation group developed bilateral lung injury as assessed by significantly higher histological score, larger increase in lung weight, poorer oxygenation, and worse respiratory mechanics compared with the ligation + FiCO2 5% group. In the ligation group, the right lung received a larger fraction of Vt and inflammation was more represented, whereas CO2 dampened both processes. Conclusions: Mechanical ventilation induces bilateral lung injury within 48 hours in healthy pigs undergoing left pulmonary artery ligation. Inhalation of 5% CO2 prevents injury, likely through decreased stress to the right lung and antiinflammatory effects.
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Affiliation(s)
| | | | | | | | - Yu-Mei Wang
- Department of Anesthesia, Critical Care and Emergency
- Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China; and
| | | | | | | | | | - Thomas Langer
- School of Medicine and Surgery, University of Milan–Bicocca, Niguarda Ca’ Granda Hospital, Milan, Italy
| | | | - Gianluca Lopez
- Department of Biomedical Surgical and Dental Sciences, University of Milan, Milan, Italy
- Division of Pathology, and
| | - Caterina Lonati
- Center for Preclinical Research, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Valentina Vaira
- Department of Pathophysiology and Transplantation
- Division of Pathology, and
| | | | - Stefano Ferrero
- Department of Biomedical Surgical and Dental Sciences, University of Milan, Milan, Italy
- Division of Pathology, and
| | - Stefano Gatti
- Center for Preclinical Research, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alberto Zanella
- Department of Pathophysiology and Transplantation
- Department of Anesthesia, Critical Care and Emergency
| | - Antonio Pesenti
- Department of Pathophysiology and Transplantation
- Department of Anesthesia, Critical Care and Emergency
| | - Tommaso Mauri
- Department of Pathophysiology and Transplantation
- Department of Anesthesia, Critical Care and Emergency
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Silva LC, Angrimani DS, Regazzi FM, Lúcio CF, Veiga GA, Fernandes CB, Vannucchi CI. Exogenous surfactant replacement immediately at birth as preventive therapy for lung prematurity in neonatal lambs. Theriogenology 2021; 171:14-20. [PMID: 34000686 DOI: 10.1016/j.theriogenology.2021.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 11/26/2022]
Abstract
Surfactant treatment is a manner to reduce alveolar superficial tension and increase pulmonary compliance in premature neonates. Thus, we aimed to analyze the effect of exogenous surfactant treatment in combination with manual ventilation for preterm lambs. We used 15 ewes and their lambs (n = 16), prematurely born at 135 days. At birth, lambs were submitted to orotracheal intubation attached to a handheld resuscitation device and randomly allocated to: Control Group (n = 5; only manual ventilation), Single Surfactant Group (n = 5; manual ventilation coupled by intratracheal administration of 100 mg/kg surfactant) and Double Surfactant Group (n = 6; surfactant volume was divided into two doses (50 mg/kg + 50 mg/kg) administrated at birth and 30 min thereafter). A complete physical exam, arterial gas analysis, blood glucose, urea and creatinine concentration and chest radiographic assessment were performed at fixed times. All lambs had decreased body temperature until 20 min after birth. However, control and double surfactant groups reached a thermic plateau after 30 min. Regardless of the time-point, control lambs had higher heart rate in comparison to treated neonates, including bradycardia in Single Surfactant Group. Single instillation led to lower oxygenation degree, compared to the Double Surfactant Group, suggesting that surfactant treatment was not able to adequately spread within the alveoli. Lambs treated with surfactant had severe impairment of aerobic activity, leading to anaerobic metabolism. All groups had hypercapnia, which can be explained by inadequate respiratory pattern and pulmonary opacity (89% of the lambs had severe or moderate lung content). In conclusion, exogenous surfactant therapy in association with manual ventilation is ineffective in reverting pulmonary immaturity of the preterm lamb, leading to less vitality, hypoxemia, delayed pulmonary clearance and high mortality rate.
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Affiliation(s)
- Liege Cg Silva
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Rua Prof. Dr. Orlando Marques de Paiva, 87, São Paulo, SP, 05508-270, Brazil
| | - Daniel Sr Angrimani
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Rua Prof. Dr. Orlando Marques de Paiva, 87, São Paulo, SP, 05508-270, Brazil
| | - Fernanda M Regazzi
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Rua Prof. Dr. Orlando Marques de Paiva, 87, São Paulo, SP, 05508-270, Brazil
| | - Cristina F Lúcio
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Rua Prof. Dr. Orlando Marques de Paiva, 87, São Paulo, SP, 05508-270, Brazil
| | - Gisele Al Veiga
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Rua Prof. Dr. Orlando Marques de Paiva, 87, São Paulo, SP, 05508-270, Brazil
| | - Claudia B Fernandes
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Rua Prof. Dr. Orlando Marques de Paiva, 87, São Paulo, SP, 05508-270, Brazil
| | - Camila I Vannucchi
- Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, Rua Prof. Dr. Orlando Marques de Paiva, 87, São Paulo, SP, 05508-270, Brazil.
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Silva LCG, Regazzi FM, Lúcio CF, Veiga GAL, Angrimani DSR, Fernandes CB, Vannucchi CI. Redox, acid-base and clinical analysis of preterm and term neonatal lambs. Anim Reprod 2018; 15:51-55. [PMID: 33365095 PMCID: PMC7746214 DOI: 10.21451/1984-3143-2017-ar0054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
During pregnancy, fetal lambs are exposed to low oxygen tension. Thus, an effective antioxidant
mechanism is partially developed which sensitizes fetus to oxidative stress. Consequently,
term and preterm neonates are susceptible to molecular and cellular injury caused by oxygen
species (ROS). This study aimed to evaluate the development of antioxidant enzymes and oxidative
profile of preterm (135 days of pregnancy) and term (145 days of pregnancy) neonatal lambs,
correlating with clinical analysis. Preterm lambs had significantly (P ≤ 0.05) lower
score of vitality (4.00 ± 1.10), bradycardia (99 ± 34 bpm) and bradypnea (13
± 10 mpm). However, both groups were normothermic and euglycemic. Preterm group had
low blood pH (7.07 ± 0.10) and both groups had hypercapnia, more severe in preterm group
(85.52 ± 18.65 mmHg). In addition, premature newborns had lower pO2 (10.67
± 5.65 mmHg) and SO2 (6.17 ± 5.85%) values. No significant difference
(P ≥ 0.05) on antioxidant enzymes and oxidative stress were verified among experimental
groups, although glutathione peroxidase negatively correlated with Apgar score, heart
rate, SO2 and pO2. Our data show that preterm neonates are less adapted
to the odds of labor and to overcome the immediate changes of extra-uterine life. Furthermore,
we verified an influence of glutathione peroxidase in controlling oxidative stress, which
highlights mature enzymatic mechanisms of cell redox, even in premature lambs.
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Hummler HD, Banke K, Wolfson MR, Buonocore G, Ebsen M, Bernhard W, Tsikas D, Fuchs H. The Effects of Lung Protective Ventilation or Hypercapnic Acidosis on Gas Exchange and Lung Injury in Surfactant Deficient Rabbits. PLoS One 2016; 11:e0147807. [PMID: 26840779 PMCID: PMC4739580 DOI: 10.1371/journal.pone.0147807] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 01/08/2016] [Indexed: 01/11/2023] Open
Abstract
Background Permissive hypercapnia has been shown to reduce lung injury in subjects with surfactant deficiency. Experimental studies suggest that hypercapnic acidosis by itself rather than decreased tidal volume may be a key protective factor. Objectives To study the differential effects of a lung protective ventilatory strategy or hypercapnic acidosis on gas exchange, hemodynamics and lung injury in an animal model of surfactant deficiency. Methods 30 anesthetized, surfactant-depleted rabbits were mechanically ventilated (FiO2 = 0.8, PEEP = 7cmH2O) and randomized into three groups: Normoventilation-Normocapnia (NN)-group: tidal volume (Vt) = 7.5 ml/kg, target PaCO2 = 40 mmHg; Normoventilation-Hypercapnia (NH)-group: Vt = 7.5 ml/kg, target PaCO2 = 80 mmHg by increasing FiCO2; and a Hypoventilation-Hypercapnia (HH)-group: Vt = 4.5 ml/kg, target PaCO2 = 80 mmHg. Plasma lactate and interleukin (IL)-8 were measured every 2 h. Animals were sacrificed after 6 h to perform bronchoalveolar lavage (BAL), to measure lung wet-to-dry weight, lung tissue IL-8, and to obtain lung histology. Results PaO2 was significantly higher in the HH-group compared to the NN-group (p<0.05), with values of the NH-group between the HH- and NN-groups. Other markers of lung injury (wet-dry-weight, BAL-Protein, histology-score, plasma-IL-8 and lung tissue IL-8) resulted in significantly lower values for the HH-group compared to the NN-group and trends for the NH-group towards lower values compared to the NN-group. Lactate was significantly lower in both hypercapnia groups compared to the NN-group. Conclusion Whereas hypercapnic acidosis may have some beneficial effects, a significant effect on lung injury and systemic inflammatory response is dependent upon a lower tidal volume rather than resultant arterial CO2 tensions and pH alone.
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Affiliation(s)
- Helmut D. Hummler
- Division of Neonatology and Pediatric Critical Care, Department of Pediatrics, Children’s Hospital, Ulm University, 89070 Ulm, Germany
- * E-mail:
| | - Katharina Banke
- Division of Neonatology and Pediatric Critical Care, Department of Pediatrics, Children’s Hospital, Ulm University, 89070 Ulm, Germany
| | - Marla R. Wolfson
- Departments of Physiology, Medicine and Pediatrics, CENTRe: Collaborative for Environmental and Neonatal Therapeutics Research; Temple Lung Center; Center for Inflammation, Translational and Clinical Lung Research, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Giuseppe Buonocore
- Pediatric Neonatology Unit, Department of Molecular and Developmental Medicine, University Hospital of Siena, Siena, Italy
| | - Michael Ebsen
- Institute for Pathology, Medizinisches Versorgungszentrum, Staedtisches Krankenhaus Kiel, Germany
| | - Wolfgang Bernhard
- Department of Neonatology, Children’s Hospital, University of Tuebingen, Tuebingen, Germany
| | - Dimitrios Tsikas
- Centre of Pharmacology and Toxicology, Hannover Medical School, Hannover, Germany
| | - Hans Fuchs
- Division of Neonatology and Pediatric Critical Care, Department of Pediatrics, Children’s Hospital, Ulm University, 89070 Ulm, Germany
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Thome UH, Genzel-Boroviczeny O, Bohnhorst B, Schmid M, Fuchs H, Rohde O, Avenarius S, Topf HG, Zimmermann A, Faas D, Timme K, Kleinlein B, Buxmann H, Schenk W, Segerer H, Teig N, Gebauer C, Hentschel R, Heckmann M, Schlösser R, Peters J, Rossi R, Rascher W, Böttger R, Seidenberg J, Hansen G, Zernickel M, Alzen G, Dreyhaupt J, Muche R, Hummler HD. Permissive hypercapnia in extremely low birthweight infants (PHELBI): a randomised controlled multicentre trial. THE LANCET RESPIRATORY MEDICINE 2015; 3:534-43. [PMID: 26088180 DOI: 10.1016/s2213-2600(15)00204-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/08/2015] [Accepted: 05/14/2015] [Indexed: 02/02/2023]
Abstract
BACKGROUND Tolerating higher partial pressure of carbon dioxide (pCO2) in mechanically ventilated, extremely low birthweight infants might reduce ventilator-induced lung injury and bronchopulmonary dysplasia. We aimed to test the hypothesis that higher target ranges for pCO2 decrease the rate of bronchopulmonary dysplasia or death. METHODS In this randomised multicentre trial, we recruited infants from 16 tertiary care perinatal centres in Germany with birthweight between 400 g and 1000 g and gestational age 23-28 weeks plus 6 days, who needed endotracheal intubation and mechanical ventilation within 24 h of birth. Infants were randomly assigned to either a high target or control group. The high target group aimed at pCO2 values of 55-65 mm Hg on postnatal days 1-3, 60-70 mm Hg on days 4-6, and 65-75 mm Hg on days 7-14, and the control target at pCO2 40-50 mmHg on days 1-3, 45-55 mm Hg on days 4-6, and 50-60 mm Hg on days 7-14. The primary outcome was death or moderate to severe bronchopulmonary dysplasia, defined as need for mechanical pressure support or supplemental oxygen at 36 weeks postmenstrual age. Cranial ultrasonograms were assessed centrally by a masked paediatric radiologist. This trial is registered with the ISRCTN registry, number ISRCTN56143743. RESULTS Between March 1, 2008, and July 31, 2012, we recruited 362 patients of whom three dropped out, leaving 179 patients in the high target and 180 in the control group. The trial was stopped after an interim analysis (n=359). The rate of bronchopulmonary dysplasia or death in the high target group (65/179 [36%]) did not differ significantly from the control group (54/180 [30%]; p=0·18). Mortality was 25 (14%) in the high target group and 19 (11%; p=0·32) in the control group, grade 3-4 intraventricular haemorrhage was 26 (15%) and 21 (12%; p=0·30), and the rate of severe retinopathy recorded was 20 (11%) and 26 (14%; p=0·36). INTERPRETATION Targeting a higher pCO2 did not decrease the rate of bronchopulmonary dysplasia or death in ventilated preterm infants. The rates of mortality, intraventricular haemorrhage, and retinopathy did not differ between groups. These results suggest that higher pCO2 targets than in the slightly hypercapnic control group do not confer increased benefits such as lung protection. FUNDING Deutsche Forschungsgemeinschaft.
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Affiliation(s)
- Ulrich H Thome
- Division of Neonatology, University Hospital for Children and Adolescents, University of Leipzig, Leipzig, Germany.
| | - Orsolya Genzel-Boroviczeny
- Division of Neonatology, Dr. von Hauner University Children's Hospital, Ludwig Maximilian University of Munich, Munich, Germany
| | - Bettina Bohnhorst
- Division of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Manuel Schmid
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, University of Ulm, Ulm, Germany
| | - Hans Fuchs
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, Albert Ludwigs University Freiburg, Freiburg, Germany
| | - Oliver Rohde
- Division of Neonatology and Pediatric Critical Care, Elisabeth Children's Hospital, Klinikum Oldenburg, Medical Campus, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Stefan Avenarius
- Hospital for General Pediatrics and Neonatology, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Hans-Georg Topf
- Division of Neonatology, University Hospital for Children and Adolescents, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Andrea Zimmermann
- Mutter-Kind-Zentrum, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Dirk Faas
- University Hospital for General Pediatrics and Neonatology, Justus Liebig University Giessen, Giessen, Germany
| | - Katharina Timme
- Division of Neonatology, Hospital for Children and Adolescents, Vivantes-Hospital Neukölln, Berlin, Berlin, Germany
| | - Barbara Kleinlein
- Hospital for Children and Adolescents, Children's Hospital of the Third Order, Munich, Germany
| | - Horst Buxmann
- Division of Neonatology, University Hospital for Children and Adolescents of the J.W. Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Wilfried Schenk
- Hospital for Children and Adolescents, Central Hospital Augsburg, Augsburg, Germany
| | - Hugo Segerer
- St. Hedwig Hospital, University of Regensburg, Regensburg, Germany
| | - Norbert Teig
- Department of Neonatology and Pediatric Intensive Care, Katholisches Klinikum, Ruhr University Bochum, Bochum, Germany
| | - Corinna Gebauer
- Division of Neonatology, University Hospital for Children and Adolescents, University of Leipzig, Leipzig, Germany
| | - Roland Hentschel
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, Albert Ludwigs University Freiburg, Freiburg, Germany
| | - Matthias Heckmann
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, Ernst Moritz Arndt University Greifswald, Greifswald, Germany
| | - Rolf Schlösser
- Division of Neonatology, University Hospital for Children and Adolescents of the J.W. Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Jochen Peters
- Hospital for Children and Adolescents, Children's Hospital of the Third Order, Munich, Germany
| | - Rainer Rossi
- Division of Neonatology, Hospital for Children and Adolescents, Vivantes-Hospital Neukölln, Berlin, Berlin, Germany
| | - Wolfgang Rascher
- Division of Neonatology, University Hospital for Children and Adolescents, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Ralf Böttger
- Hospital for General Pediatrics and Neonatology, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Jürgen Seidenberg
- Division of Neonatology and Pediatric Critical Care, Elisabeth Children's Hospital, Klinikum Oldenburg, Medical Campus, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Gesine Hansen
- Division of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Maria Zernickel
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, University of Ulm, Ulm, Germany
| | - Gerhard Alzen
- Division of Pediatric Radiology, University Hospital of the Justus Liebig University Giessen, Giessen, Germany
| | - Jens Dreyhaupt
- Institute of Epidemiology and Medical Biometry, University of Ulm, Ulm, Germany
| | - Rainer Muche
- Institute of Epidemiology and Medical Biometry, University of Ulm, Ulm, Germany
| | - Helmut D Hummler
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, University of Ulm, Ulm, Germany
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Makari D, Checchia PA, DeVincenzo J. Rationale for full-season dosing for passive antibody prophylaxis of respiratory syncytial virus. Hum Vaccin Immunother 2013; 10:607-14. [PMID: 24316863 PMCID: PMC4130285 DOI: 10.4161/hv.27426] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/26/2013] [Accepted: 12/04/2013] [Indexed: 02/02/2023] Open
Abstract
Palivizumab monthly injections throughout the RSV season prevent severe respiratory syncytial virus (RSV) disease in preterm infants ≤ 35 wGA. However, some RSV guidelines currently recommend stopping palivizumab after 3 months of age in the midst of the RSV season. This article evaluates the need for full-season dosing by reviewing the pharmacokinetic properties of palivizumab and RSV hospitalization (RSVH) risk as a function of chronologic age. Precise human palivizumab protective levels are not established. Clinical trials show significant interpatient variability in palivizumab serum trough concentrations. Partial season dosing is associated with increased risk of RSVH. For late-preterm infants, data suggest that the risk of RSVH remains elevated through at least 6 months of age. Monthly, full-season palivizumab dosing provides the only empirically proven protection from RSVH. In conclusion, late-preterm infants are at significant risk for RSVH through at least 6 months of age and would benefit from dosing throughout the RSV season.
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Affiliation(s)
| | - Paul A Checchia
- Texas Children’s Hospital; Baylor College of Medicine; Houston, TX USA
| | - John DeVincenzo
- Departments of Pediatrics; Microbiology, Immunology and Molecular Biology; University of Tennessee School of Medicine; Memphis, TN USA
- Children’s Foundation Research Institute; Le Bonheur Children’s Hospital; Memphis, TN USA
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8
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Hypercapnic acidosis attenuates ventilation-induced lung injury by a nuclear factor-κB–dependent mechanism. Crit Care Med 2012; 40:2622-30. [DOI: 10.1097/ccm.0b013e318258f8b4] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Sewing ACP, Kantores C, Ivanovska J, Lee AH, Masood A, Jain A, McNamara PJ, Tanswell AK, Jankov RP. Therapeutic hypercapnia prevents bleomycin-induced pulmonary hypertension in neonatal rats by limiting macrophage-derived tumor necrosis factor-α. Am J Physiol Lung Cell Mol Physiol 2012; 303:L75-87. [DOI: 10.1152/ajplung.00072.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Bleomycin-induced lung injury is characterized in the neonatal rat by inflammation, arrested lung growth, and pulmonary hypertension (PHT), as observed in human infants with severe bronchopulmonary dysplasia. Inhalation of CO2 (therapeutic hypercapnia) has been described to limit cytokine production and to have anti-inflammatory effects on the injured lung; we therefore hypothesized that therapeutic hypercapnia would prevent bleomycin-induced lung injury. Spontaneously breathing rat pups were treated with bleomycin (1 mg/kg/d ip) or saline vehicle from postnatal days 1–14 while being continuously exposed to 5% CO2 (PaCO2 elevated by 15–20 mmHg), 7% CO2 (PaCO2 elevated by 35 mmHg), or normocapnia. Bleomycin-treated animals exposed to 7%, but not 5%, CO2, had significantly attenuated lung tissue macrophage influx and PHT, as evidenced by normalized pulmonary vascular resistance and right ventricular systolic function, decreased right ventricular hypertrophy, and attenuated remodeling of pulmonary resistance arteries. The level of CO2 neither prevented increased tissue neutrophil influx nor led to improvements in decreased lung weight, septal thinning, impaired alveolarization, or decreased numbers of peripheral arteries. Bleomycin led to increased expression and content of lung tumor necrosis factor (TNF)-α, which was found to colocalize with tissue macrophages and to be attenuated by exposure to 7% CO2. Inhibition of TNF-α signaling with the soluble TNF-2 receptor etanercept (0.4 mg/kg ip from days 1–14 on alternate days) prevented bleomycin-induced PHT without decreasing tissue macrophages and, similar to CO2, had no effect on arrested alveolar development. Our findings are consistent with a preventive effect of therapeutic hypercapnia with 7% CO2 on bleomycin-induced PHT via attenuation of macrophage-derived TNF-α. Neither tissue macrophages nor TNF-α appeared to contribute to arrested lung development induced by bleomycin. That 7% CO2 normalized pulmonary vascular resistance and right ventricular function without improving inhibited airway and vascular development suggests that vascular hypoplasia does not contribute significantly to functional changes of PHT in this model.
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Affiliation(s)
- A. Charlotte P. Sewing
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Crystal Kantores
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Julijana Ivanovska
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Alvin H. Lee
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Azhar Masood
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Amish Jain
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Patrick J. McNamara
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - A. Keith Tanswell
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Robert P. Jankov
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Heart and Stroke Richard Lewar Centre of Excellence, University of Toronto, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
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Kapetanakis T, Siempos II, Metaxas EI, Kopterides P, Agrogiannis G, Patsouris E, Lazaris AC, Stravodimos KG, Roussos C, Armaganidis A. Metabolic acidosis may be as protective as hypercapnic acidosis in an ex-vivo model of severe ventilator-induced lung injury: a pilot study. BMC Anesthesiol 2011; 11:8. [PMID: 21486492 PMCID: PMC3087686 DOI: 10.1186/1471-2253-11-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Accepted: 04/13/2011] [Indexed: 11/10/2022] Open
Abstract
Background There is mounting experimental evidence that hypercapnic acidosis protects against lung injury. However, it is unclear if acidosis per se rather than hypercapnia is responsible for this beneficial effect. Therefore, we sought to evaluate the effects of hypercapnic (respiratory) versus normocapnic (metabolic) acidosis in an ex vivo model of ventilator-induced lung injury (VILI). Methods Sixty New Zealand white rabbit ventilated and perfused heart-lung preparations were used. Six study groups were evaluated. Respiratory acidosis (RA), metabolic acidosis (MA) and normocapnic-normoxic (Control - C) groups were randomized into high and low peak inspiratory pressures, respectively. Each preparation was ventilated for 1 hour according to a standardized ventilation protocol. Lung injury was evaluated by means of pulmonary edema formation (weight gain), changes in ultrafiltration coefficient, mean pulmonary artery pressure changes as well as histological alterations. Results HPC group gained significantly greater weight than HPMA, HPRA and all three LP groups (P = 0.024), while no difference was observed between HPMA and HPRA groups regarding weight gain. Neither group differ on ultrafiltration coefficient. HPMA group experienced greater increase in the mean pulmonary artery pressure at 20 min (P = 0.0276) and 40 min (P = 0.0012) compared with all other groups. Histology scores were significantly greater in HP vs. LP groups (p < 0.001). Conclusions In our experimental VILI model both metabolic acidosis and hypercapnic acidosis attenuated VILI-induced pulmonary edema implying a mechanism other than possible synergistic effects of acidosis with CO2 for VILI attenuation.
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Affiliation(s)
- Theodoros Kapetanakis
- "G, P, Livanos and M, Simou" Laboratories, "Evangelismos" General Hospital, University of Athens Medical School, Athens, Greece.
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12
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Bench-to-bedside review: hypercapnic acidosis in lung injury--from 'permissive' to 'therapeutic'. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2010; 14:237. [PMID: 21067531 PMCID: PMC3220022 DOI: 10.1186/cc9238] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Modern ventilation strategies for patients with acute lung injury and acute respiratory distress syndrome frequently result in hypercapnic acidosis (HCA), which is regarded as an acceptable side effect ('permissive hypercapnia'). Multiple experimental studies have demonstrated advantageous effects of HCA in several lung injury models. To date, however, human trials studying the effect of carbon dioxide per se on outcome in patients with lung injury have not been performed. While significant concerns regarding HCA remain, in particular the possible unfavorable effects on bacterial killing and the inhibition of pulmonary epithelial wound repair, the potential for HCA in attenuating lung injury is promising. The underlying mechanisms by which HCA exerts its protective effects are complex, but dampening of the inflammatory response seems to play a pivotal role. After briefly summarizing the physiological effects of HCA, a critical analysis of the available evidence on the potential beneficial effects of therapeutic HCA from in vitro, ex vivo and in vivo lung injury models and from human studies will be reviewed. In addition, the potential concerns in the clinical setting will be outlined.
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13
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Peltekova V, Engelberts D, Otulakowski G, Uematsu S, Post M, Kavanagh BP. Hypercapnic acidosis in ventilator-induced lung injury. Intensive Care Med 2010; 36:869-78. [PMID: 20213072 DOI: 10.1007/s00134-010-1787-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 02/09/2010] [Indexed: 10/19/2022]
Abstract
RATIONALE Permissive hypercapnia is established in lung injury management. Therapeutic hypercapnia causes benefit or harm, depending on the context. Ventilator-associated lung injury has a wide spectrum of candidate mechanisms, affording multiple opportunities for intervention such as hypercapnia to exert benefit or harm. OBJECTIVES To confirm (1) that hypercapnia attenuates in vivo ventilator-induced lung injury (VILI); (2) biological plausibility of such protection (e.g., dose-response, time series, inflammatory profile); and (3) that the associated biochemical events are consistently beneficial. METHODS A mouse model of VILI was established in vivo. Injurious ventilation was established, hypercapnia applied and markers of inflammation measured. MEASUREMENTS Lung injury was quantified by gas exchange, elastance, microvascular leak, histology and levels of cytokines and eicosanoids, cyclooxygenase and tissue nitrotyrosine. MAIN RESULTS Injurious ventilation caused significant lung injury (mechanics, microvascular leak, histology) and release of inflammatory cytokines, chemokines and eicosanoids. Hypercapnia attenuated these responses, with dose-response and time-dependent effects. No adverse effects of hypercapnia were observed in controls. Hypercapnia suppressed the transcription (mRNA) and translation (protein) of the major inducible prostanoid-generating enzyme (COX-2), but the effects on the downstream eicosanoids were modest. However, hypercapnia significantly increased lung tissue nitrotyrosine-at PaCO(2) levels that were protective. CONCLUSIONS Hypercapnia provided consistent and biologically plausible in vivo protection against VILI, but elevated lung tissue levels of nitro-tyrosine as previously described in sepsis. Clinicians and those designing clinical trials need to be aware of the potential for detrimental effects when using hypercapnia in order to balance benefits versus harm with this approach.
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Affiliation(s)
- Vanya Peltekova
- Physiology and Experimental Medicine, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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14
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MacCarrick MJ, Torbati D, Kimura D, Raszynski A, Zeng W, Totapally BR. Does hypercapnia ameliorate hyperoxia-induced lung injury in neonatal rats? Lung 2009; 188:235-40. [PMID: 20033196 DOI: 10.1007/s00408-009-9211-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 11/29/2009] [Indexed: 12/28/2022]
Abstract
Therapeutic hypercapnia (TH), an intentional inhalation of CO(2), has been shown to improve pulmonary function in certain models of lung injury. We tested the null hypothesis that TH does not improve hyperoxic lung injury in neonatal rats. The prospective, randomized study was set at Research laboratory in Children's Hospital. Forty-five newborn rats were randomly assigned to three groups (n = 15/group), and exposed to 96 h of normoxia (FiO(2) = 0.21), hyperoxia (FiO(2) > 0.98), and TH (FiO(2) = 0.95, FiCO(2) = 0.05). Lung histology, wet-weight to dry-weight ratio, and concentrations of pro- and anti-inflammatory cytokines (IL-1beta, IL-6, TNF-alpha, and IL-10) were used to evaluate pulmonary damage. Using a scale of 0-4, the total scores for lungs hypercellularity, inflammation, and hemorrhage was significantly increased from a median value of 1.5 in normoxia to 2.5 in hyperoxia (P < 0.05) and 3.0 with TH (P < 0.001, nonparametric ANOVA). The interstitial space relative to the alveolar space, as a measure of hypercellularity, was increased by 18% during hyperoxia and by 44% with TH compared with normoxia. TH significantly increased the size of the interstitial space by 22% compared with hyperoxia (P < 0.001). The lung wet-weight to dry-weight ratio was increased by 10% in both hyperoxic groups (P < 0.001). Both hyperoxic groups showed significant reductions in the concentration of IL-1beta compared with normoxia (P < 0.001), whereas the ratio of IL-1beta to IL-10 was significantly decreased, indicating an anti-inflammatory trend. TH does not prevent histological manifestations of hyperoxic lung injury in spontaneously breathing neonatal rats and may worsen the outcome.
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Affiliation(s)
- Matthew J MacCarrick
- Division of Critical Care Medicine, Miami Children's Hospital, 3100 SW 62nd Avenue, Miami, FL 33155, USA
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15
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Masood A, Yi M, Lau M, Belcastro R, Shek S, Pan J, Kantores C, McNamara PJ, Kavanagh BP, Belik J, Jankov RP, Tanswell AK. Therapeutic effects of hypercapnia on chronic lung injury and vascular remodeling in neonatal rats. Am J Physiol Lung Cell Mol Physiol 2009; 297:L920-30. [DOI: 10.1152/ajplung.00139.2009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Permissive hypercapnia, achieved using low tidal volume ventilation, has been an effective protective strategy in patients with acute respiratory distress syndrome. To date, no such protective effect has been demonstrated for the chronic neonatal lung injury, bronchopulmonary dysplasia. The objective of our study was to determine whether evolving chronic neonatal lung injury, using a rat model, is resistant to the beneficial effects of hypercapnia or simply requires a less conservative approach to hypercapnia than that applied clinically to date. Neonatal rats inhaled air or 60% O2 for 14 days with or without 5.5% CO2. Lung parenchymal neutrophil and macrophage numbers were significantly increased by hyperoxia alone, which was associated with interstitial thickening and reduced secondary crest formation. The phagocyte influx, interstitial thickening, and impaired alveolar formation were significantly attenuated by concurrent hypercapnia. Hyperoxic pups that received 5.5% CO2 had a significant increase in alveolar number relative to air-exposed pups. Increased tyrosine nitration, a footprint for peroxynitrite-mediated reactions, arteriolar medial wall thickening, and both reduced small peripheral pulmonary vessel number and VEGF and angiopoietin-1 (Ang-1) expression, which were observed with hyperoxia, was attenuated by concurrent hypercapnia. We conclude that evolving chronic neonatal lung injury in a rat model is responsive to the beneficial effects of hypercapnia. Inhaled 5.5% CO2 provided a significant degree of protection against parenchymal and vascular injury in an animal model of chronic neonatal lung injury likely due, at least in part, to its inhibition of a phagocyte influx.
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Affiliation(s)
- Azhar Masood
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Man Yi
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Mandy Lau
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Rosetta Belcastro
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
| | - Samuel Shek
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
| | - Jingyi Pan
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
| | - Crystal Kantores
- Clinical Integrative Biology, Sunnybrook Research Institute; and
| | - Patrick J. McNamara
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Paediatrics, and
| | - Brian P. Kavanagh
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Departments of 4Anaesthesia,
- Critical Care Medicine,
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Jaques Belik
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Paediatrics, and
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Robert P. Jankov
- Clinical Integrative Biology, Sunnybrook Research Institute; and
- Paediatrics, and
- Physiology, University of Toronto, Toronto, Ontario, Canada
| | - A. Keith Tanswell
- Canadian Institutes of Health Research Group in Lung Development, and
- Lung Biology Programme, Physiology and Experimental Medicine, Hospital for Sick Children Research Institute
- Paediatrics, and
- Physiology, University of Toronto, Toronto, Ontario, Canada
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Sharabi K, Lecuona E, Helenius IT, Beitel GJ, Sznajder JI, Gruenbaum Y. Sensing, physiological effects and molecular response to elevated CO2 levels in eukaryotes. J Cell Mol Med 2009; 13:4304-18. [PMID: 19863692 PMCID: PMC4515048 DOI: 10.1111/j.1582-4934.2009.00952.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Carbon dioxide (CO2) is an important gaseous molecule that maintains biosphere homeostasis and is an important cellular signalling molecule in all organisms. The transport of CO2 through membranes has fundamental roles in most basic aspects of life in both plants and animals. There is a growing interest in understanding how CO2 is transported into cells, how it is sensed by neurons and other cell types and in understanding the physiological and molecular consequences of elevated CO2 levels (hypercapnia) at the cell and organism levels. Human pulmonary diseases and model organisms such as fungi, C. elegans, Drosophila and mice have been proven to be important in understanding of the mechanisms of CO2 sensing and response.
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Affiliation(s)
- Kfir Sharabi
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
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Bliss D, Matar M, Krishnaswami S. Should Intraoperative Hypercapnea or Hypercarbia Raise Concern in Neonates Undergoing Thoracoscopic Repair of Diaphragmatic Hernia of Bochdalek? J Laparoendosc Adv Surg Tech A 2009; 19 Suppl 1:S55-8. [DOI: 10.1089/lap.2008.0141.supp] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- David Bliss
- Department of Surgery, Oregon Health and Sciences University, Portland, Oregon
| | - Marla Matar
- Department of Anesthesia, Oregon Health and Sciences University, Portland, Oregon
| | - Sanjay Krishnaswami
- Department of Surgery, Oregon Health and Sciences University, Portland, Oregon
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18
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Hassett P, Contreras M, Laffey JG. Hypercapnia: Permissive, Therapeutic, or Not at All? Intensive Care Med 2009. [DOI: 10.1007/978-0-387-77383-4_25] [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]
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Abstract
UNLABELLED 'Permissive hypercapnia' is a familiar term in neonatal intensive care, given the widespread adoption of low-tidal-volume ventilation strategies applied with the goal of decreasing respiratory morbidity. Recent evidence suggesting that hypercapnic acidosis may itself have protective effects on the lung and other organs has led to the coining of a new phrase, 'therapeutic hypercapnia', which also encompasses the use of supplemental inspired CO(2). CONCLUSION Experimental evidence suggests that mild-moderate hypercapnia can improve tissue oxygenation and perfusion, which may ameliorate injury to the immature lung and brain. However, hypercapnia may also be associated with adverse outcomes, and the range of PaCO(2) levels that are both safe and effective for specific subsets of neonates has yet to be determined.
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Affiliation(s)
- Robert P Jankov
- Department of Paediatric, University of Toronto, Toronto, Ontario Canada.
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Frank JA, Parsons PE, Matthay MA. Pathogenetic significance of biological markers of ventilator-associated lung injury in experimental and clinical studies. Chest 2007; 130:1906-14. [PMID: 17167015 PMCID: PMC2764530 DOI: 10.1378/chest.130.6.1906] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
For patients with acute lung injury, positive pressure mechanical ventilation is life saving. However, considerable experimental and clinical data have demonstrated that how clinicians set the tidal volume, positive end-expiratory pressure, and plateau airway pressure influences lung injury severity and patient outcomes including mortality. In order to better identify ventilator-associated lung injury (VALI), clinical investigators have sought to measure blood-borne and airspace biological markers of VALI. At the same time, several laboratory-based studies have focused on biological markers of inflammation and organ injury in experimental models in order to clarify the mechanisms of ventilator-induced lung injury (VILI) and VALI. This review summarizes data on biological markers of VALI and VILI from both clinical and experimental studies with an emphasis on markers identified in patients and in the experimental setting. This analysis suggests that measurement of some of these biological markers may be of value in diagnosing VALI and in understanding its pathogenesis.
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Affiliation(s)
- James A Frank
- Division of Pulmonary and Critical Care Medicine, University of California-San Francisco, 4150 Clement Street, Mail Stop 111D, San Francisco, CA 94121, USA.
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21
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Li G, Zhou D, Vicencio AG, Ryu J, Xue J, Kanaan A, Gavrialov O, Haddad GG. Effect of carbon dioxide on neonatal mouse lung: a genomic approach. J Appl Physiol (1985) 2006; 101:1556-64. [PMID: 16888043 DOI: 10.1152/japplphysiol.01031.2005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Despite the deleterious effects associated with elevated carbon dioxide (CO(2)) or hypercapnia, it has been hypothesized that CO(2) can protect the lung from injury. However, the effects of chronic hypercapnia on the neonatal lung are unknown. Hence, we investigated the effect of chronic hypercapnia on neonatal mouse lung to identify genes that could potentially contribute to hypercapnia-mediated lung protection. Newborn mouse litters were exposed to 8% CO(2), 12% CO(2), or room air for 2 wk. Lungs were excised and analyzed for morphometric alterations. The alveolar walls of CO(2)-exposed mice appeared thinner than those of controls. Analyses of gene expression differences by microarrays revealed that genes from a variety of functional categories were differentially expressed following hypercapnia treatment, including those encoding growth factors, chemokines, cytokines, and endopeptidases. In particular and of major interest, the expression level of genes encoding surfactant proteins A and D, as well as chloride channel calcium-activated 3, were significantly increased, but the expression of WNT1-inducible signaling pathway protein 2 was significantly decreased. The significant changes in gene expression occurred mostly at 8% CO(2), but only a few at 12% CO(2). Our results lead us to conclude that 1) there are a number of gene families that may contribute to hypercapnia-mediated lung protection; 2) the upregulation of surfactant proteins A and D may play a role as anti-inflammatory or antioxidant agents; and 3) the effects of CO(2) seem to depend on the level to which the lung is exposed.
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Affiliation(s)
- Guangyu Li
- Department of Pediatrics, University of California San Diego, San Diego, California 92093-0735, USA
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22
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Abstract
Bronchopulmonary dysplasia (BPD), initially described 40 years ago, is a dynamic clinical entity that continues to affect tens of thousands of premature infants each year. BPD was first characterized as a fibrotic pulmonary endpoint following severe Respiratory Distress Syndrome (RDS). It was the result of pulmonary healing after RDS, high oxygen exposure, positive pressure ventilation, and poor bronchial drainage secondary to endotracheal intubation in premature infants. With improved treatment for RDS, including surfactant replacement, oxygen saturation monitoring, improved modes of mechanical ventilation, antibiotic therapies, nutritional support, and infants surviving at younger gestations, the clinical picture of BPD has changed. In the following pages, we will summarize the multifaceted pathophysiologic factors leading to the pulmonary changes in "new" BPD, which is primarily characterized by disordered or delayed development. The contribution of hyperoxia and hypoxia, mechanical forces, vascular maldevelopment, inflammation, fluid management, patent ductus arteriosus (PDA), nutrition, and genetics will be discussed.
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Affiliation(s)
- Patricia R Chess
- Department of Pediatrics, University of Rochester, Rochester, NY 14642, USA.
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Abstract
BACKGROUND Recent improvements in the survival of extremely preterm infants have been accompanied by evolution in the pathogenesis and histopathology of bronchopulmonary dysplasia (BPD). Although oxygen and barotrauma-induced injury remain important contributing factors, pulmonary developmental arrest appears to play an equally important causal role in prolonged respiratory illness, especially among the most immature surviving preterm newborns. To date, clinical trials have failed to demonstrate a substantial benefit of a single treatment or preventive strategy for BPD. OBJECTIVES To evaluate the current evidence in favor of treatments that might prevent BPD. METHODS Review of clinical studies of preventive treatment strategies for BPD. RESULTS High frequency oscillatory ventilation, permissive hypercapnea, and inhaled nitric oxide might offer benefit to infants at risk of BPD. These and other potential preventive therapies for BPD, such as superoxide dismutase, inositol, and alpha(1)-proteinase inhibitor, deserve further study. CONCLUSIONS Although some current treatments offer promise, no preventive therapy for BPD has proven safe and effective, except for intramuscular vitamin A. Additional studies of respiratory technologies, management strategies, and protective molecules are needed.
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Affiliation(s)
- Linda J Van Marter
- Children's Hospital, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass., USA.
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Doerr CH, Gajic O, Berrios JC, Caples S, Abdel M, Lymp JF, Hubmayr RD. Hypercapnic acidosis impairs plasma membrane wound resealing in ventilator-injured lungs. Am J Respir Crit Care Med 2005; 171:1371-7. [PMID: 15695495 PMCID: PMC2718480 DOI: 10.1164/rccm.200309-1223oc] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Accepted: 01/21/2005] [Indexed: 12/22/2022] Open
Abstract
The objective of this study was to assess the effects of hypercapnic acidosis on lung cell injury and repair by confocal microscopy in a model of ventilator-induced lung injury. Three groups of normocapnic, hypocapnic, and hypercapnic rat lungs were perfused ex vivo, either during or after injurious ventilation, with a solution containing the membrane-impermeant label propidium iodide. In lungs labeled during injurious ventilation, propidium iodide fluorescence identifies all cells with plasma membrane wounds, both permanent and transient, whereas in lungs labeled after injurious ventilation propidium iodide fluorescence identifies only cells with permanent plasma membrane wounds. Hypercapnia minimized the adverse effects of high-volume ventilation on vascular barrier function, whereas hypocapnia had the opposite effect. Despite CO2-dependent differences in lung mechanics and edema the number of injured subpleural cells per alveolus was similar in the three groups (0.48 +/- 0.34 versus 0.51 +/- 0.19 versus 0.43 +/- 0.20 for hypocapnia, normocapnia, and hypercapnia, respectively). However, compared with normocapnia the probability of wound repair was significantly reduced in hypercapnic lungs (63 versus 38%; p < 0.02). This finding was subsequently confirmed in alveolar epithelial cell scratch models. The potential relevance of these observations for lung inflammation and remodeling after mechanical injury is discussed.
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Affiliation(s)
- Clinton H Doerr
- Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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25
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Abstract
PURPOSE OF REVIEW Neonatologists and pulmonary biologists have long sought preventive treatments for bronchopulmonary dysplasia (BPD). The purpose of this review is to highlight recent reports of a number of potential treatments intended to prevent BPD and to discuss the controversies surrounding preventive strategies. RECENT FINDINGS The evolution of BPD from a disorder of pulmonary injury affecting moderately preterm infants, to one characterized by a developmental pulmonary arrest among survivors of extreme prematurity has important implications for BPD prevention. Recent recognition that the pathogenesis of BPD might have prenatal origins raises new challenges and opportunities for studies of BPD prevention; however, most current preventive strategies for BPD focus on respiratory management. Neither past nor current clinical trials have shown a conclusive benefit of a single preventive treatment strategy. Promising but still largely unproven preventive respiratory treatments include: high frequency oscillatory ventilation, permissive hypercapnea, and inhaled nitric oxide. Observational and recent laboratory data support the need for randomized clinical trials of continuous positive airway pressure versus mechanical ventilation. Additionally, clinical trials are needed to address the deficit in our knowledge of the potential benefits and risks of postnatal low dose corticosteroid treatment. Further study of superoxide dismutase, inositol, and alpha-1 proteinase inhibitor also are warranted on the basis of recent clinical trials or meta-analyses. SUMMARY Only Vitamin A has proven a safe and effective preventive treatment for BPD. Additional studies of respiratory technologies, management strategies, and protective molecules are needed. Directed cytokine and genetic therapies are on the horizon.
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Affiliation(s)
- Linda J Van Marter
- Children's Hospital and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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Lang JD, Figueroa M, Sanders KD, Aslan M, Liu Y, Chumley P, Freeman BA. Hypercapnia via reduced rate and tidal volume contributes to lipopolysaccharide-induced lung injury. Am J Respir Crit Care Med 2004; 171:147-57. [PMID: 15477499 DOI: 10.1164/rccm.200302-305oc] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Appreciating that CO2 modifies the chemical reactivity of nitric oxide (NO)-derived inflammatory oxidants, we investigated whether hypercapnia would modulate pulmonary inflammatory responses. Rabbits (n = 72) were ventilated with approximately 7-ml/kg tidal volume for 6 hours. Animals were randomized to one of the following conditions: eucapnia (Pa(CO2) at approximately 35-40 mm Hg), eucapnia + lipopolysaccharide (LPS), eucapnia + LPS + inhaled NO (iNO delivered at approximately 20 ppm), hypercapnia (Pa(CO2) at approximately 60 mm Hg), hypercapnia + LPS, and hypercapnia + LPS + iNO. The hypercapnia + LPS groups compared with groups exposed to eucapnia + LPS displayed significantly increased bronchoalveolar lavage fluid protein concentrations (p < 0.05), lung wet-to-dry ratios (p < 0.05), bronchoalveolar lavage fluid cell counts (p < 0.05), and lung histologic alterations consistent with greater injury. Furthermore, expression of inducible nitric oxide synthase (p < 0.05), tissue myeloperoxidase content (p < 0.05), and formation of lung protein 3-nitrotyrosine derivatives (p < 0.05) was greatest under conditions of hypercapnia + LPS. Groups exposed to hypercapnic conditions without LPS did not manifest these changes. The inhalation of iNO attenuated selected indices of lung injury. We conclude that hypercapnia induced by means of reduced rate and tidal volume amplifies pulmonary inflammatory responses.
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Affiliation(s)
- John D Lang
- Department of Anesthesiology, The University of Alabama at Birmingham, Birmingham, Alabama 35233-6810, USA.
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27
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Abstract
The pathology of BPD has changed over time, with the old BPD characterized by airway injury, inflammation, and parenchymal fibrosis giving way to the new BPD manifesting less fibrosis but with decreased alveolar and vascular development. The pathogenesis of BPD involves factors affecting the severity and management of RDS, alterations in lung development and maturation, alveolar-vascular interactions, and extracellular matrix remodeling. These factors in pathogenesis are mediated and modulated by hyperoxic lung injury, antioxidants, NO, the pulmonary neuroendocrine system and peptide growth factors, the immune system, and various genetic polymorphisms and predispositions. Future therapeutic interventions are likely to target one or more of these abnormalities in lung development, maturation, and response to injury.
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Affiliation(s)
- Namasivayam Ambalavanan
- Division of Neonatology, Department of Pediatrics, University of Alabama at Birmingham, 620 South 20th Street, Birmingham, AL 35233, USA.
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Rai S, Engelberts D, Laffey JG, Frevert C, Kajikawa O, Martin TR, Post M, Kavanagh BP. Therapeutic hypercapnia is not protective in the in vivo surfactant-depleted rabbit lung. Pediatr Res 2004; 55:42-9. [PMID: 14561781 DOI: 10.1203/01.pdr.0000098502.72182.55] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Permissive hypercapnia because of reduced tidal volume is associated with improved survival in lung injury, whereas therapeutic hypercapnia-deliberate elevation of arterial Pco2-protects against in vivo reperfusion injury and injury produced by severe lung stretch. No published studies to date have examined the effects of CO2 on in vivo models of neonatal lung injury. We used an established in vivo rabbit model of surfactant depletion to investigate whether therapeutic hypercapnia would improve oxygenation and protect against ventilator-induced lung injury. Animals were randomized to injurious (tidal volume, 12 mL/kg; positive end-expiratory pressure, 0 cm H2O) or protective ventilatory strategy (tidal volume, 5 mL/kg; positive end-expiratory pressure, 12.5 cm H2O), and to receive either control conditions or therapeutic hypercapnia (fraction of inspired CO2, 0.12). Oxygenation (alveolar-arterial O2 difference, arterial Po2), lung injury (alveolar-capillary protein leak, impairment of static compliance), and selected bronchoalveolar lavage and plasma cytokines (IL-8, growth-related oncogene, monocyte chemoattractant protein-1, and tumor necrosis factor-alpha) were measured. Injurious ventilation resulted in a large alveolar-arterial O2 gradient, elevated peak airway pressure, increased protein leak, and impaired lung compliance. Therapeutic hypercapnia did not affect any of these outcomes. Tumor necrosis factor-alpha was not increased by mechanical stretch in any of the groups. Therapeutic hypercapnia abolished the stretch-induced increase in bronchoalveolar lavage monocyte chemoattractant protein-1, but did not affect any of the other mediators studied. Therapeutic hypercapnia may attenuate the impairment in oxygenation and inhibit certain cytokines. Because hypercapnia inhibits certain cytokines but does not alter lung injury, the pathogenic role of these cytokines in lung injury is questionable.
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Affiliation(s)
- Sharadindu Rai
- The Lung Biology Program, The Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
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Laffey JG, Jankov RP, Engelberts D, Tanswell AK, Post M, Lindsay T, Mullen JB, Romaschin A, Stephens D, McKerlie C, Kavanagh BP. Effects of Therapeutic Hypercapnia on Mesenteric Ischemia–Reperfusion Injury. Am J Respir Crit Care Med 2003; 168:1383-90. [PMID: 14644926 DOI: 10.1164/rccm.2108078] [Citation(s) in RCA: 75] [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
Hypercapnic acidosis protects against direct lung injury in in vivo and ex vivo models, however, lung injury/acute respiratory distress syndrome commonly occurs after a nonpulmonary etiology. We investigated whether therapeutic hypercapnia (TH)-deliberate elevation of carbon dioxide (CO2) tension-would protect against lung injury after splanchnic ischemia-reperfusion injury in an in vivo model. TH was associated with preservation of lung mechanics, attenuation of protein leakage, and improved oxygenation compared with control conditions. Lung protection was therapeutic as well as prophylactic. Protection was dose-dependent, but inspired CO2 concentrations above 5.0% were associated with little additional lung protection. Before lung injury, increasing FICO2 resulted in a dose-dependent increase in PaO2. Lung protection with hypercapnia occurred despite pulmonary artery pressures that were greater than observed with normocapnia. Reperfusion increased lipid peroxidation (tissue 8-isoprostane concentration) in the bowel, liver, and lung, and caused histologically apparent bowel injury; however, none of these effects was altered by TH. Therefore, TH-induced by adding CO2 to inspired gas-provides consistent protection against lung injury in terms of lung permeability, oxygenation, and lung mechanics after mesenteric ischemia-reperfusion. These data further support the emerging evidence for ongoing physiologic study of TH at the bedside.
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Affiliation(s)
- John G Laffey
- Department of Critical Care Medicine, The Research Institute, The Hospital for Sick Children, Toronto, ON, Canada
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