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Danan C, Tauzin M, Jung C, Carbonnier B, Dassieu G, Decobert F, Caeymaex L. Instrumental dead space: A glass ceiling for extremely low birth weight preterm infants? A dead space washout bench study. Pediatr Pulmonol 2023; 58:1514-1519. [PMID: 36785523 DOI: 10.1002/ppul.26353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 01/22/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023]
Abstract
BACKGROUND When ventilating extremely low birth weight infants, clinicians face the problem of instrumental dead space, which is often larger than tidal volume. Hence, aggressive ventilation is necessary to achieve CO2 removal. Continuous tracheal gas insufflation can wash out CO2 from dead space and might also have an impact on O2 and water vapor transport. The objective of this bench study is to test the impact of instrumental dead space on the transport of CO2 , O2 , and water vapor and the ability of continuous tracheal gas insufflation to remedy this problem during small tidal volume ventilation. METHODS A test-lung located in an incubator at 37°C was ventilated with pressure levels needed to reach different tidal volumes from 1.5 to 5 mL. End-tidal CO2 at the test-lung exit, O2 concentration, and relative humidity in the test-lung were measured for each tidal volume with and without a 0.2 L/min continuous tracheal gas insufflation flow. RESULTS CO2 clearance was improved by continuous tracheal gas insufflation allowing a 28%-44% of tidal volume reduction. With continuous tracheal gas insufflation, time to reach desired O2 concentration was reduced from 20% to 80% and relative humidity was restored. These results are inversely related to tidal volume and are particularly critical below 3 mL. CONCLUSION For the smallest tidal volumes, reduction of instrumental dead space seems mandatory for CO2 , O2 , and water vapor transfer. Continuous tracheal gas insufflation improved CO2 clearance, time to reach desired O2 concentration and humidification of airways and, thus, may be an option to protect lung development.
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Affiliation(s)
- Claude Danan
- Neonatal Intensive Care Unit, CHI Créteil, Créteil, France.,INSERM CNRS ERL 7000, IMRB, Université Paris Est Creteil, Créteil, France
| | - Manon Tauzin
- Neonatal Intensive Care Unit, CHI Créteil, Créteil, France
| | - Camille Jung
- Clinical Research Centre, Centre Hospitalier Intercommunal de Créteil, Créteil, France.,Pediatrics, Centre Hospitalier Intercommunal de Creteil, Créteil, France
| | | | - Gilles Dassieu
- Neonatal Intensive Care Unit, CHI Créteil, Créteil, France.,INSERM CNRS ERL 7000, IMRB, Université Paris Est Creteil, Créteil, France
| | - Fabrice Decobert
- Neonatal Intensive Care Unit, CHI Créteil, Créteil, France.,INSERM CNRS ERL 7000, IMRB, Université Paris Est Creteil, Créteil, France
| | - Laurence Caeymaex
- Neonatal Intensive Care Unit, CHI Créteil, Créteil, France.,Faculté de Santé, University Paris Est Creteil, Créteil, Val de Marne, France
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Modulation of defensive airway reflexes during continuous positive airway pressure in the rabbit. Respir Physiol Neurobiol 2018; 257:87-92. [DOI: 10.1016/j.resp.2018.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 02/02/2018] [Accepted: 02/18/2018] [Indexed: 12/12/2022]
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Kubaski F, Tomatsu S, Patel P, Shimada T, Xie L, Yasuda E, Mason R, Mackenzie WG, Theroux M, Bober MB, Oldham HM, Orii T, Shaffer TH. Non-invasive pulmonary function test on Morquio patients. Mol Genet Metab 2015; 115:186-92. [PMID: 26116954 PMCID: PMC4706533 DOI: 10.1016/j.ymgme.2015.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 06/19/2015] [Accepted: 06/20/2015] [Indexed: 12/13/2022]
Abstract
In clinical practice, respiratory function tests are difficult to perform in Morquio syndrome patients due to their characteristic skeletal dysplasia, small body size and lack of cooperation of young patients, where in some cases, conventional spirometry for pulmonary function is too challenging. To establish feasible clinical pulmonary endpoints and determine whether age impacts lung function in Morquio patients non-invasive pulmonary tests and conventional spirometry were evaluated. The non-invasive pulmonary tests: impulse oscillometry system, pneumotachography, and respiratory inductance plethysmography in conjunction with conventional spirometry were evaluated in twenty-two Morquio patients (18 Morquio A and 4 Morquio B) (7 males), ranging from 3 to 40 years of age. Twenty-two patients were compliant with non-invasive tests (100%) with the exception of IOS (81.8%-18 patients). Seventeen patients (77.3%) were compliant with spirometry testing. All subjects had normal vital signs at rest including >95% oxygen saturation, end tidal CO2 (38-44 mmHg), and age-appropriate heart rate (mean=98.3, standard deviation=19) (two patients were deviated). All patients preserved normal values in the impulse oscillometry system, pneumotachography, and respiratory inductance plethysmography, although predicted forced expiratory total (72.8±6.9 SE%) decreased with age and was below normal; phase angle (35.5±16.5°), %rib cage (41.6±12.7%), resonant frequency, and forced expiratory volume in 1 s/forced expiratory volume total (110.0±3.2 SE%) were normal and not significantly impacted by age. The proposed non-invasive pulmonary function tests are able to cover a greater number of patients (young patients and/or wheel-chair bound), thus providing a new diagnostic approach for the assessment of lung function in Morquio syndrome which in many cases may be difficult to evaluate. Morquio patients studied herein demonstrated no clinical or functional signs of restrictive and/or obstructive lung disease.
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Affiliation(s)
- Francyne Kubaski
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Shunji Tomatsu
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Department of Pediatrics, Gifu University, Gifu, Japan.
| | - Pravin Patel
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Tsutomu Shimada
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Li Xie
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Eriko Yasuda
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Robert Mason
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | | | - Mary Theroux
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Michael B Bober
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Helen M Oldham
- Department of Respiratory Care, Nemours/Alfred I. DuPont Hospital for Children, Wilmington, DE, USA
| | - Tadao Orii
- Department of Pediatrics, Gifu University, Gifu, Japan
| | - Thomas H Shaffer
- Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Center for Pediatric Lung Research, Nemours/Alfred I. DuPont Hospital for Children, Wilmington, DE, USA.
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Jassar RK, Vellanki H, Zhu Y, Hesek AM, Wang J, Rodriguez E, Wolfson MR, Shaffer TH. High flow nasal heliox improves work of breathing and attenuates lung injury in a newborn porcine lung injury model. J Neonatal Perinatal Med 2015; 8:323-331. [PMID: 26757007 DOI: 10.3233/npm-15915039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
BACKGROUND High flow nasal cannula (HFNC) has been shown to improve ventilation and oxygenation and reduce work of breathing in newborns with respiratory distress. Heliox, decreases resistance to airflow, reduces the work of breathing, facilitates the distribution of inspired gas, and has been shown to attenuate lung inflammation during the treatment of acute lung injury. HYPOTHESIS Heliox delivered by HFNC will decrease resistive load, decrease work of breathing, improve ventilation and attenuate lung inflammation during spontaneous breathing following acute lung injury in the newborn pig. METHODS Spontaneously breathing neonatal pigs received Nitrox or Heliox by HFNC and studied over 4 hrs following oleic acid injury. Gas exchange, pulmonary mechanics and systemic inflammation were measured serially. Lung inflammation biomarkers were assessed at termination. RESULTS Heliox breathing animals demonstrated lower work of breathing reflected by lower tracheal pressure, phase angle and phase relationship. Ventilation efficiency index was greater compared to Nitrox. Heliox group showed less lung inflammation reflected by lower tissue interleukin-6 and 8. CONCLUSION High flow nasal Heliox decreased respiratory load, reduced resistive work of breathing indices and attenuated lung inflammatory profile while ventilation was supported at less pressure effort in the presence of acute lung injury.
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Affiliation(s)
- R K Jassar
- Neonatology, Alfred I. duPont Hospital for Children, Wilmington, DE, USA
- Neonatology, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - H Vellanki
- Neonatology, Alfred I. duPont Hospital for Children, Wilmington, DE, USA
- Neonatology, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Yan Zhu
- Alfred I. duPont Hospital for Children, Center for Pediatric Lung Research, Wilmington, DE, USA
| | - A M Hesek
- Alfred I. duPont Hospital for Children, Center for Pediatric Lung Research, Wilmington, DE, USA
| | - J Wang
- Alfred I. duPont Hospital for Children, Center for Pediatric Lung Research, Wilmington, DE, USA
| | - E Rodriguez
- Alfred I. duPont Hospital for Children, Center for Pediatric Lung Research, Wilmington, DE, USA
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - M R Wolfson
- Temple University School of Medicine, Departments of Physiology, Pediatrics, and Medicine, Center for Inflammation, Translational and Clinical Lung Research, Philadelphia, PA, USA
| | - T H Shaffer
- Alfred I. duPont Hospital for Children, Center for Pediatric Lung Research, Wilmington, DE, USA
- Temple University School of Medicine, Department of Physiology and Pediatrics, Philadelphia, PA, USA
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Jassar RK, Vellanki H, Zhu Y, Hesek A, Wang J, Rodriguez E, Wu J, Shaffer TH, Wolfson MR. High flow nasal cannula (HFNC) with Heliox decreases diaphragmatic injury in a newborn porcine lung injury model. Pediatr Pulmonol 2014; 49:1214-22. [PMID: 24500982 PMCID: PMC4122654 DOI: 10.1002/ppul.23000] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 12/24/2013] [Accepted: 01/05/2014] [Indexed: 11/06/2022]
Abstract
BACKGROUND High flow nasal cannula (HFNC) improves ventilation by washing out nasopharyngeal dead space while delivering oxygen. Heliox (helium-oxygen gas mixture), a low-density gas mixture, decreases resistance to airflow, reduces the work of breathing, and facilitates distribution of inspired gas. Excessive lung work and potential injury increases the workload on the immature diaphragm predisposing the muscle to fatigue, and can lead to inflammatory and oxidative stress, thereby contributing to impaired diaphragmatic function. We tested the hypothesis that HFNC with Heliox will decrease the work of breathing thereby unloading the neonatal diaphragm, and potentially reducing diaphragmatic injury. METHODS Spontaneously breathing neonatal pigs were randomized to Nitrox (nitrogen-oxygen gas mixture) or Heliox, and studied over 4 hr following oleic acid injury. Gas exchange, pulmonary mechanics indices, and systemic markers of inflammation were measured serially. Diaphragm inflammation biomarkers and histology for muscle injury were assessed at termination. RESULTS Heliox breathing animals demonstrated decreased respiratory load and work of breathing with lower pressure-rate product, lower labored breathing index, and lower levels of diaphragmatic inflammatory markers, and muscle injury score as compared to Nitrox. CONCLUSION These results suggest that HFNC with Heliox is a useful adjunct to attenuate diaphragmatic fatigue in the presence of lung injury by unloading the diaphragm, resulting in a more efficient breathing pattern, and decreased diaphragm injury.
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Affiliation(s)
- Romal K Jassar
- Neonatology, Alfred I. duPont Hospital for Children, Wilmington, Delaware; Neonatology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania
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Comparison Study of Airway Reactivity Outcomes due to a Pharmacologic Challenge Test: Impulse Oscillometry versus Least Mean Squared Analysis Techniques. Pulm Med 2013; 2013:618576. [PMID: 23691308 PMCID: PMC3649693 DOI: 10.1155/2013/618576] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 03/06/2013] [Accepted: 03/07/2013] [Indexed: 11/18/2022] Open
Abstract
The technique of measuring transpulmonary pressure and respiratory airflow with manometry and pneumotachography using the least mean squared analysis (LMS) has been used broadly in both preclinical and clinical settings for the evaluation of neonatal respiratory function during tidal volume breathing for lung tissue and airway frictional mechanical properties measurements. Whereas the technique of measuring respiratory function using the impulse oscillation technique (IOS) involves the assessment of the relationship between pressure and flow using an impulse signal with a range of frequencies, requires less cooperation and provides more information on total respiratory system resistance (chest wall, lung tissue, and airways). The present study represents a preclinical animal study to determine whether these respiratory function techniques (LMS and IOS) are comparable in detecting changes in respiratory resistance derived from a direct pharmacological challenge.
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Pulmonary function tests in emergency department pediatric patients with acute wheezing/asthma exacerbation. Pulm Med 2012; 2012:724139. [PMID: 23304496 PMCID: PMC3523566 DOI: 10.1155/2012/724139] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 10/23/2012] [Accepted: 10/23/2012] [Indexed: 11/17/2022] Open
Abstract
Background. Pulmonary function tests (PFT) have been developed to analyze tidal breathing in patients who are minimally cooperative due to age and respiratory status. This study used tidal breathing tests in the ED to measure asthma severity. Design/Method. A prospective pilot study in pediatric patients (3 to 18 yrs) with asthma/wheezing was conducted in an ED setting using respiratory inductance plethysmography and pneumotachography. The main outcome measures were testing feasibility, compliance, and predictive value for admission versus discharge. Results. Forty patients were studied, of which, 14 (35%) were admitted. Fifty-five percent of the patients were classified as a mild-intermittent asthmatic, 30% were mild-persistent asthmatics, 12.5% were moderate-persistent asthmatics, and 2.5% were severe-persistent. Heart rate was higher in admitted patients as was labored breathing index, phase angle, and asthma score. Conclusions. Tidal breathing tests provide feasible, objective assessment of patient status in the enrolled age group and may assist in the evaluation of acute asthma exacerbation in the ED. Our results demonstrate that PFT measurements, in addition to asthma scores, may be useful in indicating the severity of wheezing/asthma and the need for admission.
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Olivant Fisher A, Husain K, Wolfson MR, Hubert TL, Rodriguez E, Shaffer TH, Theroux MC. Hyperoxia during one lung ventilation: inflammatory and oxidative responses. Pediatr Pulmonol 2012; 47:979-86. [PMID: 22431368 PMCID: PMC3888791 DOI: 10.1002/ppul.22517] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 12/05/2011] [Indexed: 12/22/2022]
Abstract
BACKGROUND It is common practice during one lung ventilation (OLV) to use 100% oxygen, although this may cause hyperoxia- and oxidative stress-related lung injury. We hypothesized that lower oxygen (FiO(2) ) during OLV will result in less inflammatory and oxidative lung injury and improved lung function. METHODS Twenty pigs (8.88 ± 0.84 kg; 38 ± 4.6 days) were assigned to either the hyperoxia group (n = 10; FiO(2) = 100%) or the normoxia group (n = 10; FiO(2) < 50%). Both groups were subjected to 3 hr of OLV. Blood samples were tested for pro-inflammatory cytokines and lung tissue was tested for these cytokines and oxidative biomarkers. RESULTS There were no differences between groups for partial pressure of CO(2) , tidal volume, end-tidal CO(2) , plasma cytokines, or respiratory compliance. Total respiratory resistance was greater in the hyperoxia group (P = 0.02). There were higher levels of TNF-α, IL-1β, and IL-6 in the lung homogenates of the hyperoxia group than in the normoxia group (P ≤ 0.01, 0.001, and 0.001, respectively). Myeloperoxidase and protein carbonyls (PC) were higher (P = 0.03 and P = 0.01, respectively) and superoxide dismutase (SOD) was lower in the lung homogenates of the hyperoxia group (P ≤ 0.001). CONCLUSION Higher myeloperoxidase, PC, and cytokine levels, and lower SOD availability indicate a greater degree of injury in the lungs of the hyperoxia animals, possibly from using 100% oxygen. In this translational study using a pig model, FiO(2) ≤ 50% during OLV reduced hyperoxic injury and improved function in the lungs.
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Affiliation(s)
- Alicia Olivant Fisher
- Nemours Biomedical Research, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE19803, USA.
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Rodriguez E, Bober MB, Davey L, Zamora A, Li Puma AB, Chidekel A, Shaffer TH. Respiratory mechanics in an infant with perinatal lethal hypophosphatasia treated with human recombinant enzyme replacement therapy. Pediatr Pulmonol 2012; 47:917-22. [PMID: 22328548 DOI: 10.1002/ppul.22527] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 11/24/2011] [Indexed: 11/09/2022]
Abstract
Hypophosphatasia is a rare autosomal recessive disorder caused by deficient activity of tissue nonspecific alkaline phosphatase (TNSALP) and characterized by defective bone mineralization. In the perinatal lethal form, respiratory complications due to rachitic deformities of the thoracic cage and associated hypoplastic lungs are present. ENB-0040 is a bone-targeted human recombinant TNSALP fusion protein that aims to restore skeletal mineralization. The goal of this study was to characterize pulmonary and thoracic cage mechanics in an infant with the perinatal lethal form of hypophosphatasia under enzyme replacement therapy. Pulmonary function testing was performed on a preterm, 8-week-old patient with hypophosphatasia who was mechanically ventilated since birth because of severe chest wall insufficiency. The measurements consisted of respiratory impulse oscillation measurements (resistance and reactance), ventilatory mechanics (compliance and resistance), and thoracoabdominal motion (TAM) analysis. At baseline, chest wall compliance was 50% of normal, and the TAM indicated predominantly abdominal displacement. After 12 weeks of treatment, a consistent decrease in ventilator requirements and improvement in lung function and chest wall mechanics were observed and correlated with thoracic cage radiologic findings. Measurable changes in chest wall dynamics and respiratory mechanics using noninvasive technology were useful for respiratory management and therapeutic guidance of ENB-0040 treatment in this patient.
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Affiliation(s)
- Elena Rodriguez
- Nemours Research Lung Center, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA.
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Czernik C, Schmalisch G, Bührer C, Proquitté H. Weaning of neonates from mechanical ventilation by use of nasopharyngeal high-frequency oscillatory ventilation: a preliminary study. J Matern Fetal Neonatal Med 2011; 25:374-8. [DOI: 10.3109/14767058.2011.580401] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
OBJECTIVE To characterize physical and inflammatory injury that may result from repeated intubation, independent of positive-pressure ventilation; and to determine whether corticosteroids can attenuate injury and or inflammation that may result from repeated intubation. DESIGN A 4-hr animal protocol. SETTING All work was done in the animal laboratory at the Alfred I. DuPont Hospital for Children. SUBJECTS Neonatal piglets (2-8 days old; 2.5 ± 0.4 kg) were intubated and randomized to four groups (n = 8 each) to be followed over 4 hrs. Groups were control (not reintubated), injured (reintubated every 0.5 hr), intratracheal pretreatment with 1 mg of nebulized budesonide (intratracheal pretreated), or intravenous pretreatment with 0.3 mg/kg of dexamethasone (intravenous pretreated). INTERVENTION Each pig was sedated for the duration of study and had a 3.5F catheter inserted in the femoral artery for blood sampling and blood pressure measurement every hour. After 4 hrs, each pig was killed, and tissue was harvested for histology and interleukin-6 assays. MEASUREMENTS AND MAIN RESULTS Laryngeal tissue interleukin-6 content was greater in the injured group compared with the control group (p < .05). In the intratracheal pretreated group, the interleukin-6 content of laryngeal tissue was greater compared with the control group (p < .05), whereas the intravenous pretreated group was not different from the control group. The reintubation injury resulted in plasma interleukin-6 levels that, compared with control, were greater in the injured and intratracheal pretreated groups (p < .05). Quantitative histology showed that the degree of tracheal injury was higher in injured and intratracheal pretreated groups compared with the control group (p < .05). CONCLUSIONS Repeated intubation alone results in significant tracheal trauma and systemic inflammation. Intravenous but not inhaled steroids attenuated the injury.
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Frizzola M, Miller TL, Rodriguez ME, Zhu Y, Rojas J, Hesek A, Stump A, Shaffer TH, Dysart K. High-flow nasal cannula: impact on oxygenation and ventilation in an acute lung injury model. Pediatr Pulmonol 2011; 46:67-74. [PMID: 21171186 PMCID: PMC3332105 DOI: 10.1002/ppul.21326] [Citation(s) in RCA: 156] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Revised: 06/14/2010] [Accepted: 06/15/2010] [Indexed: 12/20/2022]
Abstract
INTRODUCTION High-flow nasal cannula therapy (HFNC) has been shown to be more effective than continuous positive airway pressure (CPAP) in reducing intubations and ventilator days. HFNC likely provides mechanisms to support respiratory efficiency beyond application of distending pressure. We reason that HFNC washout of nasopharyngeal dead space impacts CO(2) removal along with oxygenation. The aim of this study was to demonstrate the flow dependence of CO(2) reduction and improved oxygenation during HFNC and the dependence on leak around the nasal prongs. MATERIALS AND METHODS Neonatal piglets (n=13; 2-6 kg) were injured with IV oleic acid and supported with HFNC at 2 through 8 L/min. High and low leak around the nasal prongs was accomplished by using single and double prong cannulae, respectively. Measurement of hemodynamic, respiratory and blood gas parameters were made at each setting following 10 min for physiologic equilibration. Tracheal pressures were recorded by transmural catheters. RESULTS With HFNC, CO(2) trended downward in a flow-dependent manner independent of leak. Oxygenation and tracheal pressures increased in a flow-dependent manner with the greatest effect during double prong. At 8 L/min, tracheal pressures did not exceed 6 ± 1 cmH(2) O. CONCLUSIONS HFNC improves gas exchange in a flow-dependent manner; double prong had greater impact on O(2;) single prong had greater impact on CO(2) elimination.
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Affiliation(s)
- Meg Frizzola
- Nemours Children's Clinic of Wilmington, The Nemours Foundation, Alfred I. duPont Children's Hospital, Primary Research Institution, Wilmington, Delaware 19803, USA.
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Guo ZL, Liang YJ, Lu GP, Wang JC, Ren T, Zheng YH, Gong JY, Yu J. Tracheal gas insufflation with partial liquid ventilation to treat LPS-induced acute lung injury in juvenile piglets. Pediatr Pulmonol 2010; 45:700-7. [PMID: 20672361 DOI: 10.1002/ppul.21257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVES Partial liquid ventilation (PLV) with perfluorocarbons (PFC) seems not superior to conventional ventilation clinically. We hypothesized that a combination of continuous tracheal gas insufflation (TGI) with protective strategy of PLV (low dose of PFC, low inflation pressure, moderate inhalation of oxygen and moderate anesthesia) would improve cardiopulmonary function in acute lung injury. METHODS Twenty-four healthy juvenile piglets were anesthetized and mechanically ventilated at PEEP of 2 cmH(2)O with a peak inspiratory pressure of 10 cmH(2)O and FIO(2) of 0.4. The piglets were challenged with lipopolysaccharide and randomly assigned to four groups (n = 6 each): (1) mechanical ventilation alone (MV); (2) PLV with perfluorodecalin (10 ml/kg); (3) TGI with continuous airway flow 2 L/min; and (4) combination of PLV and TGI. The outcome was assessed functionally and histologically. RESULTS All treatments except MV improved pH, PaO(2)/FIO(2), PaCO(2), ventilation efficacy index (VEI) and tidal volume. Both PLV-associated treatments also improved heart rate, respiratory rate, pulse contour cardiac output, systemic vascular resistance, dynamic lung compliance, mean airway resistance and mean airway pressure. The combination group resulted in higher PaO(2)/FIO(2), VEI and a better lung histology score than any other treatments. CONCLUSIONS The new protective strategy may provide a better treatment for sepsis-induced acute lung injury.
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Affiliation(s)
- Zhong-Liang Guo
- Department of Respiratory Medicine, East Hospital, Tongji University School of Medicine, Shanghai, China.
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Dysart K, Miller TL, Wolfson MR, Shaffer TH. Research in high flow therapy: mechanisms of action. Respir Med 2009; 103:1400-5. [PMID: 19467849 DOI: 10.1016/j.rmed.2009.04.007] [Citation(s) in RCA: 441] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 04/14/2009] [Accepted: 04/15/2009] [Indexed: 12/17/2022]
Abstract
Recently, heater/humidifier devices that use novel methods to condition breathing gases from an external source have been introduced. The addition of sufficient warmth and high levels of humidification to breathing gas has allowed for higher flow rates from nasal cannula devices to be applied to patients (i.e., high flow therapy). This article provides a review of the proposed mechanisms behind the efficacy of high flow therapy via nasal cannula, which include washout of nasopharyngeal dead space, attenuation of the inspiratory resistance associated with the nasopharynx, improvement in conductance and pulmonary compliance, mild distending pressure and reduction in energy expenditure for gas conditioning.
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Affiliation(s)
- Kevin Dysart
- Department of Pediatrics, Jefferson Medical College/Thomas Jefferson University, Philadelphia, PA, USA.
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Chong E, Dysart KC, Chidekel A, Locke R, Shaffer TH, Miller TL. Heat shock protein 70 secretion by neonatal tracheal tissue during mechanical ventilation: association with indices of tissue function and modeling. Pediatr Res 2009; 65:387-91. [PMID: 19127221 PMCID: PMC2676716 DOI: 10.1203/pdr.0b013e31819913f5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mechanical ventilation (MV) of the neonatal airway alters mechanical properties and activates tissue-modeling pathways. Heat shock protein (HSP70) is a marker of tissue injury and modulates inflammation, which may influence subsequent pulmonary tissue modeling by matrix metalloproteinases (MMPs). HSP70 secretion is up-regulated in MV airway tissues and associated with changes in airway elasticity and secretion of MMPs. Proximal tracheal segments were isolated in 13 newborn lambs and were either MV for 4 h or SHAM. At baseline and hourly, tracheal segments were flushed and tracheal elasticity was determined. Tracheal wash fluid was assayed for HSP70 by ELISA and for MMPs by substrate zymography. HSP70 secretion increased from baseline to a peak at 1 h in both groups (p < 0.01), greater in the MV group (p < 0.05), and returned to baseline values by 2 h. This response was in contrast to the progressive decrease in tracheal elasticity (p < 0.05). The HSP70 elevation pattern was noted in MMP-2, but beyond 1 h, MMP-2 returned to baseline values in MV group but remained elevated in SHAM (p < 0.05). HSP70 secretion is associated with the degree of biophysical tracheal injury as well as the time course of MMP-2 secretion by tracheal tissues.
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Affiliation(s)
- Euming Chong
- Department of Pediatrics, Jefferson Medical College, Philadelphia, Pennsylvania 19107, USA.
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Danan C, Durrmeyer X, Brochard L, Decobert F, Benani M, Dassieu G. A randomized trial of delayed extubation for the reduction of reintubation in extremely preterm infants. Pediatr Pulmonol 2008; 43:117-24. [PMID: 18092355 DOI: 10.1002/ppul.20726] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To compare immediate extubation versus delayed extubation after 36 hr in extremely low-birth weight infants receiving gentle mechanical ventilation and perinatal lung protective interventions. Our hypothesis was that a delayed extubation in this setting would decrease the rate of reintubation. STUDY DESIGN/METHODOLOGY: A prospective, unmasked, randomized, controlled trial to compare immediate extubation and delayed extubation after 36 hr. Optimized ventilation in both groups included continuous tracheal gas insufflation (CTGI), prophylactic surfactant administration, low oxygen saturation target and moderate permissive hypercapnia. Successful extubation for at least 7 days was the primary criterion and ventilatory support requirements until 36 weeks gestational age the main secondary criteria. PATIENT SELECTION Eighty-six infants under 28 weeks gestational age in a single neonatal intensive tertiary care unit. RESULTS Delayed extubation (1.9 +/- 0.8 days vs. 0.5 +/- 0.7 days) did not improve the rate of successful extubation but had no long-term adverse effects. CTGI and the lung protective strategy we describe resulted in a very gentle ventilation. The rate of survival without bronchopulmonary dysplasia (BPD, defined as any respiratory support at 36 weeks gestational age) was similar in the two groups and remarkably high for the global population (78%) and for the subgroup of infants <1,000 g at birth (75%). CONCLUSIONS Adding 36 hr of optimized mechanical ventilation before first extubation does not improve the rate of successful extubation but has no adverse effects.
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Affiliation(s)
- Claude Danan
- Department of Neonatal Intensive Care Unit, Centre Hospitalier Intercommunal de Creteil, Hôpital Henri Mondor, Creteil, France.
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Miller TL, Zhu Y, Altman AR, Dysart K, Shaffer TH. Sequential alterations of tracheal mechanical properties in the neonatal lamb: effect of mechanical ventilation. Pediatr Pulmonol 2007; 42:141-9. [PMID: 17123318 DOI: 10.1002/ppul.20549] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
UNLABELLED Alterations in neonatal airway mechanics resulting from ventilatory therapies are implicated in airway collapse and chronic disease. Quantifying the functional impact of mechanical ventilation (MV) on the neonatal airway and elucidating the time course of these changes will support development of protective therapies. The objective of this study was to test the hypothesis that conventional MV would result in decreased static and dynamic elastance of an isolated tracheal segment and thinning of the muscle (trachealis) region of the tracheal wall in a time dependent manner. Tracheal segments were isolated in newborn lambs spontaneously breathing through the distal trachea; segments were MV (n = 7; PIP/PEEP = 35/5 cmH2O; 40 breaths/min) or instrumented, non-ventilated (SHAM; n = 7; PIP/PEEP = 0/0 cmH2O) for 4 hr. At baseline and hourly, tracheal segments were filled with saline, and static pressure-volume curves were constructed as the pressure response to stepwise volume infusions. Then, cross-sectional ultrasound images were captured at 0 cmH2O on SHAM, and at 0 cmH2O, peak inspiratory pressure (PIP) and positive end expiratory pressure (PEEP), on MV tracheae for subsequent dimensional analysis. Tracheal elasticity indices were derived from static pressure-volume data, and during dynamic ventilation using ultrasound images to calculate the stress-strain relationships. Over 4 hr of MV, tracheal internal diameter (ID) increased (14%; P < 0.05). Markers of tracheal mechanical properties indicated a decrease in elasticity under both static (bulk modulus; 28%; P < 0.05) and dynamic (elastic modulus; 282 %; P < 0.05) conditions, indicating a significant alteration in elastic components. No time dependent changes were identified in dimensions or mechanical properties in the SHAM group. CONCLUSIONS MV results in dimensional alterations that increased anatomical dead space and reduced static and dynamic elastance of the neonatal trachea.
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Affiliation(s)
- Thomas L Miller
- Nemours Research Lung Center, Alfred I. duPont Hospital for Children, Wilmington, Delaware 19803, USA.
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Miller TL, Altman AR, Tsuda T, Shaffer TH. An ultrasound imaging method for in vivo tracheal bulk and Young's moduli of elasticity. J Biomech 2006; 40:1615-21. [PMID: 17045275 DOI: 10.1016/j.jbiomech.2006.07.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Accepted: 07/17/2006] [Indexed: 11/21/2022]
Abstract
Alterations in neonatal airway mechanical properties resulting from ventilatory therapies such as mechanical ventilation have been implicated in airway collapse and chronic disease. Advances in ultrasound (US) technology allow for real-time imaging and accurate measurement of tracheal dimensions in vivo; thus, changes in mechanical properties can be tracked longitudinally. In this report we introduce an adaptation of engineering concepts using US imaging data to study airway mechanics in vivo. In this protocol, tracheal segments are isolated in a spontaneously breathing newborn lamb model and the segments are exposed to time-cycled, pressure-limited mechanical ventilation. Serially, tracheal segments are filled with saline and pressure-volume relationships are recorded with stepwise volume infusions. US dimensional measurements of the segments are made while static (no distending pressure) and at pressure limits during dynamic ventilator cycling. US measurements are used to normalize pressure-volume data for resting volume, calculation of bulk modulus, stress-strain relationships and the adapted Young's modulus associated with tangential wall stress. Temporal changes in bulk and Young's moduli demonstrate the time dependence of alterations in conducting airway mechanical properties in vivo during the course of mechanical ventilation. This methodology will provide a means to evaluate respiratory therapies with respect to airway mechanics.
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Affiliation(s)
- Thomas L Miller
- Nemours Research Lung Center, Alfred I. DuPont Hospital for Children, Wilmington, DE 19803, USA.
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Miller TL, Cox T, Blackson T, Paul D, Weiss K, Shaffer TH. Pulmonary function assessment in an infant with Barnes syndrome: proactive evaluation for surgical intervention. Pediatrics 2006; 118:e1264-7. [PMID: 16950944 DOI: 10.1542/peds.2006-0135] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Our aim for this study was to report pulmonary mechanics in a neonate with a severe case of Barnes syndrome, a rare form of thoracolaryngopelvic dysplasia, and to use these data to guide ventilatory support and serve as a presurgical screening tool. A comprehensive pulmonary function evaluation was performed on a 36-day-old patient with Barnes syndrome who was being mechanically ventilated because of severe pulmonary distress secondary to thoracic dystrophy. The measurements consisted of respiratory volumes including functional residual capacity, ventilatory mechanics including compliance and resistance, and thoracoabdominal synchrony. Chest wall compliance was 64% below normal, and the thoracoabdominal motion was indicative of predominantly abdominal displacement during inspiratory breaths. The lungs were functioning at a low functional residual capacity, resulting in low lung compliance and increased pulmonary resistance. As a result of the evaluation, the patient was recommended for lateral thoracic expansion surgery and the ventilatory management was adjusted to focus on end-distending pressure support.
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Affiliation(s)
- Thomas L Miller
- Nemours Research Lung Center, Alfred I. duPont Hospital for Children, 1600 Rockland Rd, Wilmington, DE 19803, USA.
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