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He LLH, Foo G, Kenna KR, Douglas E, Fatmous M, Sutton RJ, Perkins EJ, Sourial M, Pereira-Fantini PM, Tingay DG, Sett A. Lung ultrasound detects regional aeration inhomogeneity in ventilated preterm lambs. Pediatr Res 2024; 95:129-134. [PMID: 37591926 PMCID: PMC10798896 DOI: 10.1038/s41390-023-02781-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 07/04/2023] [Accepted: 07/29/2023] [Indexed: 08/19/2023]
Abstract
BACKGROUND Inhomogeneous lung aeration is a significant contributor to preterm lung injury. EIT detects inhomogeneous aeration in the research setting. Whether LUS detects inhomogeneous aeration is unknown. The aim was to determine whether LUS detects regional inhomogeneity identified by EIT in preterm lambs. METHODS LUS and EIT were simultaneously performed on mechanically ventilated preterm lambs. LUS images from non-dependent and dependent regions were acquired and reported using a validated scoring system and computer-assisted quantitative LUS greyscale analysis (Q-LUSMGV). Regional inhomogeneity was calculated by observed over predicted aeration ratio from the EIT reconstructive model. LUS scores and Q-LUSMGV were compared with EIT aeration ratios using one-way ANOVA. RESULTS LUS was performed in 32 lambs (~125d gestation, 128 images). LUS scores were greater in upper anterior (non-dependent) compared to lower lateral (dependent) regions of the left (3.4 vs 2.9, p = 0.1) and right (3.4 vs 2.7, p < 0.0087). The left and right upper regions also had greater LUS scores compared to right lower (3.4 vs 2.7, p < 0.0087) and left lower (3.7 vs 2.9, p = 0.1). Q-LUSMGV yielded similar results. All LUS findings corresponded with EIT regional differences. CONCLUSION LUS may have potential in measuring regional aeration, which should be further explored in human studies. IMPACT Inhomogeneous lung aeration is an important contributor to preterm lung injury, however, tools detecting inhomogeneous aeration at the bedside are limited. Currently, the only tool clinically available to detect this is electrical impedance tomography (EIT), however, its use is largely limited to research. Lung ultrasound (LUS) may play a role in monitoring lung aeration in preterm infants, however, whether it detects inhomogeneous lung aeration is unknown. Visual LUS scores and mean greyscale image analysis using computer assisted quantitative LUS (Q-LUSMGV) detects regional lung aeration differences when compared to EIT. This suggests LUS reliably detects aeration inhomogeneity warranting further investigation in human trials.
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Affiliation(s)
- Laura L H He
- Neonatal Research, Murdoch Children's Research Institute, Victoria, VIC, Australia.
- Department of Paediatrics, University of Melbourne, Victoria, VIC, Australia.
| | - Gillian Foo
- Joan Kirner Women's and Children's Hospital, Western Health, Victoria, VIC, Australia
| | - Kelly R Kenna
- Neonatal Research, Murdoch Children's Research Institute, Victoria, VIC, Australia
| | - Ellen Douglas
- Neonatal Research, Murdoch Children's Research Institute, Victoria, VIC, Australia
| | - Monique Fatmous
- Neonatal Research, Murdoch Children's Research Institute, Victoria, VIC, Australia
| | - Rebecca J Sutton
- Neonatal Research, Murdoch Children's Research Institute, Victoria, VIC, Australia
- Translational Research Unit, Murdoch Children's Research Institute, Victoria, VIC, Australia
| | - Elizabeth J Perkins
- Neonatal Research, Murdoch Children's Research Institute, Victoria, VIC, Australia
| | - Magdy Sourial
- Translational Research Unit, Murdoch Children's Research Institute, Victoria, VIC, Australia
| | - Prue M Pereira-Fantini
- Neonatal Research, Murdoch Children's Research Institute, Victoria, VIC, Australia
- Department of Paediatrics, University of Melbourne, Victoria, VIC, Australia
| | - David G Tingay
- Neonatal Research, Murdoch Children's Research Institute, Victoria, VIC, Australia
- Department of Paediatrics, University of Melbourne, Victoria, VIC, Australia
| | - Arun Sett
- Neonatal Research, Murdoch Children's Research Institute, Victoria, VIC, Australia
- Department of Paediatrics, University of Melbourne, Victoria, VIC, Australia
- Joan Kirner Women's and Children's Hospital, Western Health, Victoria, VIC, Australia
- Newborn Research Centre, The Royal Women's Hospital, Victoria, VIC, Australia
- Department of Obstetrics and Gynaecology, The University of Melbourne, Victoria, VIC, Australia
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2
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Liu S, Dong R, Xiong S, Shi JH. Comparison of ventilation techniques for compensation of mask leakage using a ventilator and a regular full-face mask: A bench study. Heliyon 2023; 9:e20546. [PMID: 37867853 PMCID: PMC10589781 DOI: 10.1016/j.heliyon.2023.e20546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 07/14/2023] [Accepted: 09/28/2023] [Indexed: 10/24/2023] Open
Abstract
Background The use of noninvasive ventilation (NIV) during and after extubation is common. We designed this study to determine the optimal strategy to compensate for mask leaks and achieve effective ventilation during NIV by comparing commonly used operating room ventilator systems and a regular facemask. Methods We tested four operating room ventilator systems (Dägger Zeus, Dägger Apollo, Dägger Fabius Tiro, and General Electric Healthcare Carestation 650) on a lung model with normal compliance and airway resistance and evaluated pressure control ventilation (PCV), volume control ventilation (VCV), and AutoFlow mode (VAF). We set the O2 flow at 10 L/min and the maximal flow at 13, 16, or 26 L/min. We simulated five leak levels, from no leak to over 40 L/min (I to V levels), using customized T-pieces placed between the lung model and the breathing circuit. We recorded the expired tidal volume (Vte) from the lung model and peak inspiratory pressure via two flow/pressure sensors that were placed distally and proximally to the T-pieces. Results 1. Comparison of four ventilators: with any given ventilation mode, an increase in leak level caused a decrease in Vte. With PCV, only Zeus produced Vte larger than 150 ml at leak level V. 2. Effect of ventilation mode on Vte: across all four ventilators, PCV resulted in a higher Vte than VCV and VAF (P < 0.01). PCV mode with all ventilators at leak level II provided Vte values that were equal to or greater than those obtained with no leak. 3. Effect of O2 flow on Vte Using PCV mode: only Carestation 650 Vte at leak level II during PCV were significantly greater with 16 L/min O2 flow compared with 10 L/min O2 flow (P < 0.01). 4. Actual leak: increasing the O2 flow from 10 L/min to the maximum O2 flow dramatically increased the real leak with all 4 ventilators at any fixed leak level (P < 0.01). 5. Preset PIP vs. actual PIP with PCV: at low preset PIP and leak levels such as leak II and III, the discrepancy between preset PIP and actual PIP was small. The disparity between the preset and actual PIP grew when the target PIP and the leak level were raised. Conclusion For NIV using a mask, the ventilator is preferred whose Pressure generator is Turbine, the PCV mode is preferred in the ventilation mode and the oxygen flow is set to 10 L/min or maximum oxygen flow.
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Affiliation(s)
- Shujie Liu
- Department of Anesthesiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Ran Dong
- Department of Anesthesiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Siyi Xiong
- Department of Anesthesiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
- Department of Anesthesiology, Women and Children’s Hospital of Chongqing Medical University, Chongqing, China
| | - Jing-hui Shi
- Department of Anesthesiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
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3
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Marpole R, Ohn M, O'Dea CA, von Ungern-Sternberg BS. Clinical utility of preoperative pulmonary function testing in pediatrics. Paediatr Anaesth 2022; 32:191-201. [PMID: 34875135 DOI: 10.1111/pan.14356] [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: 10/26/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 11/28/2022]
Abstract
Perioperative respiratory adverse events pose a significant risk in pediatric anesthesia, and identifying these risks is vital. Traditionally, this is assessed using history and examination. However, the perioperative risk is multifactorial, and children with complex medical backgrounds such as chronic lung disease or obesity may benefit from additional objective preoperative pulmonary function tests. This article summarizes the utility of available pulmonary function assessment tools as preoperative tests in improving post-anesthetic outcomes. Currently, there is no evidence to support or discourage any pulmonary function assessment as a routine preoperative test for children undergoing anesthesia. In addition, there is uncertainty about which patients with the known or suspected respiratory disease require preoperative pulmonary function tests, what time period prior to surgery these are required, and whether spirometry or more sophisticated tests are indicated. Therefore, the need for any test should be based on information obtained from the history and examination, the child's age, and the complexity of the surgery.
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Affiliation(s)
- Rachael Marpole
- Department of Respiratory and Sleep Medicine, Perth Children's Hospital, Nedlands, WA, Australia.,Division of Paediatrics, School of Medical, University of Western Australia, Crawley, WA, Australia
| | - Mon Ohn
- Department of Respiratory and Sleep Medicine, Perth Children's Hospital, Nedlands, WA, Australia.,Division of Paediatrics, School of Medical, University of Western Australia, Crawley, WA, Australia.,Perioperative Medicine Team, Telethon Kids Institute, Nedlands, WA, Australia
| | - Christopher A O'Dea
- Department of Respiratory and Sleep Medicine, Perth Children's Hospital, Nedlands, WA, Australia
| | - Britta S von Ungern-Sternberg
- Perioperative Medicine Team, Telethon Kids Institute, Nedlands, WA, Australia.,Division of Emergency Medicine, Anaesthesia and Pain Medicine, School of Medical, University of Western Australia, Crawley, WA, Australia.,Department of Anaesthesia and Pain Management, Perth Children's Hospital, Nedlands, WA, Australia
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4
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Bhatia R, Carlisle HR, Armstrong RK, Kamlin COF, Davis PG, Tingay DG. Extubation generates lung volume inhomogeneity in preterm infants. Arch Dis Child Fetal Neonatal Ed 2022; 107:82-86. [PMID: 34162692 DOI: 10.1136/archdischild-2021-321788] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 05/26/2021] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To evaluate the feasibility of electrical impedance tomography (EIT) to describe the regional tidal ventilation (VT) and change in end-expiratory lung volume (EELV) patterns in preterm infants during the process of extubation from invasive to non-invasive respiratory support. DESIGN Prospective observational study. SETTING Single-centre tertiary neonatal intensive care unit. PATIENTS Preterm infants born <32 weeks' gestation who were being extubated to nasal continuous positive airway pressure as per clinician discretion. INTERVENTIONS EIT measurements were taken in supine infants during elective extubation from synchronised positive pressure ventilation (SIPPV) before extubation, during and then at 2 and 20 min after commencing nasal continuous positive applied pressure (nCPAP). Extubation and pressure settings were determined by clinicians. MAIN OUTCOME MEASURES Global and regional ΔEELV and ΔVT, heart rate, respiratory rate and oxygen saturation were measured throughout. RESULTS Thirty infants of median (range) 2 (1, 21) days were extubated to a median (range) CPAP 7 (6, 8) cm H2O. SpO2/FiO2 ratio was a mean (95% CI) 50 (35, 65) lower 20 min after nCPAP compared with SIPPV. EELV was lower at all points after extubation compared with SIPPV, and EELV loss was primarily in the ventral lung (p=0.04). VT was increased immediately after extubation, especially in the central and ventral regions of the lung, but the application of nCPAP returned VT to pre-extubation patterns. CONCLUSIONS EIT was able to describe the complex lung conditions occurring during extubation to nCPAP, specifically lung volume loss and greater use of the dorsal lung. EIT may have a role in guiding peri-extubation respiratory support.
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Affiliation(s)
- Risha Bhatia
- Newborn Research, The Royal Women's Hospital, Parkville, Victoria, Australia .,Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia.,Monash Newborn, Monash Children's Hospital, Clayton, Victoria, Australia
| | - Hazel R Carlisle
- Newborn Research, The Royal Women's Hospital, Parkville, Victoria, Australia.,Department of Neonatology, Centenary Hospital for Women and Children, Canberra, Australian Capital Territory, Australia
| | - Ruth K Armstrong
- Newborn Research, The Royal Women's Hospital, Parkville, Victoria, Australia.,Neonatology, The Royal Children's Hospital Melbourne, Parkville, Victoria, Australia
| | - C Omar Farouk Kamlin
- Newborn Research, The Royal Women's Hospital, Parkville, Victoria, Australia.,Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Peter G Davis
- Newborn Research, The Royal Women's Hospital, Parkville, Victoria, Australia.,Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Obstetrics and Gynaecology, The University of Melbourne, Parkville, Victoria, Australia
| | - David G Tingay
- Newborn Research, The Royal Women's Hospital, Parkville, Victoria, Australia.,Neonatal Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia.,Neonatology, The Royal Children's Hospital Melbourne, Parkville, Victoria, Australia
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5
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Prolonged Continuous Monitoring of Regional Lung Function in Infants with Respiratory Failure. Ann Am Thorac Soc 2021; 19:991-999. [PMID: 34898392 DOI: 10.1513/annalsats.202005-562oc] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RATIONALE Electrical impedance tomography (EIT) allows instantaneous and continuous visualization of regional ventilation and changes in end-expiratory lung volume at the bedside. There is particular interest in using EIT for monitoring in critically ill neonates and young children with respiratory failure. Previous studies have focused only on short-term monitoring in small populations. The feasibility and safety of prolonged monitoring with EIT in neonates and young children has not been demonstrated yet. OBJECTIVES To evaluate the feasibility and safety of long-term EIT monitoring in a routine clinical setting and to describe changes in ventilation distribution and homogeneity over time and with positioning in a multi-center cohort of neonates and young children with respiratory failure. METHODS At four European University Hospitals, we conducted an observational study (NCT02962505) on 200 patients with post-menstrual ages (PMA) between 25 weeks and 36 months, at risk for or suffering from respiratory failure. Continuous EIT data were obtained using a novel textile 32-electrode interface and recorded at 48 images/s for up to 72 hours. Clinicians were blinded to EIT images during the recording. EIT parameters and the effects of body position on ventilation distribution were analyzed offline. RESULTS The average duration of EIT measurements was 53±20 hours. Skin contact impedance was sufficient to allow image reconstruction for valid ventilation analysis during 92[77-98]% (median[interquartile range]) of examination time. EIT examinations were well tolerated, with minor skin irritations (temporary redness or imprint) occurring in 10% of patients and no moderate or severe adverse events. Higher ventilation amplitude was found in the dorsal and right lung areas when compared with the ventral and left regions respectively. Prone positioning resulted in an increase in the ventilation-related EIT signal in the dorsal hemithorax, indicating increased ventilation of the dorsal lung areas. Lateral positioning led to a redistribution of ventilation towards the dependent lung in preterm infants and to the non-dependent lung in patients with PMA above 37 weeks. CONCLUSIONS EIT allows continuous long-term monitoring of regional lung function in neonates and young children for up to 72 hours with minimal adverse effects. Our study confirmed the presence of posture-dependent changes in ventilation distribution and their dependency on PMA in a large patient cohort. Clinical trial registered with ClinicalTrials.gov (NCT02962505).
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6
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Thomson J, Rüegger CM, Perkins EJ, Pereira-Fantini PM, Farrell O, Owen LS, Tingay DG. Regional ventilation characteristics during non-invasive respiratory support in preterm infants. Arch Dis Child Fetal Neonatal Ed 2021; 106:370-375. [PMID: 33246967 DOI: 10.1136/archdischild-2020-320449] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/14/2020] [Accepted: 11/03/2020] [Indexed: 01/04/2023]
Abstract
OBJECTIVES To determine the regional ventilation characteristics during non-invasive ventilation (NIV) in stable preterm infants. The secondary aim was to explore the relationship between indicators of ventilation homogeneity and other clinical measures of respiratory status. DESIGN Prospective observational study. SETTING Two tertiary neonatal intensive care units. PATIENTS Forty stable preterm infants born <30 weeks of gestation receiving either continuous positive airway pressure (n=32) or high-flow nasal cannulae (n=8) at least 24 hours after extubation at time of study. INTERVENTIONS Continuous electrical impedance tomography imaging of regional ventilation during 60 min of quiet breathing on clinician-determined non-invasive settings. MAIN OUTCOME MEASURES Gravity-dependent and right-left centre of ventilation (CoV), percentage of whole lung tidal volume (VT) by lung region and percentage of lung unventilated were determined for 120 artefact-free breaths/infant (4770 breaths included). Oxygen saturation, heart and respiratory rates were also measured. RESULTS Ventilation was greater in the right lung (mean 69.1 (SD 14.9)%) total VT and the gravity-non-dependent (ND) lung; ideal-actual CoV 1.4 (4.5)%. The central third of the lung received the most VT, followed by the non-dependent and dependent regions (p<0.0001 repeated-measure analysis of variance). Ventilation inhomogeneity was associated with worse peripheral capillary oxygen saturation (SpO2)/fraction of inspired oxygen (FiO2) (p=0.031, r2 0.12; linear regression). In those infants that later developed bronchopulmonary dysplasia (n=25), SpO2/FiO2 was worse and non-dependent ventilation inhomogeneity was greater than in those that did not (both p<0.05, t-test Welch correction). CONCLUSIONS There is high breath-by-breath variability in regional ventilation patterns during NIV in preterm infants. Ventilation favoured the ND lung, with ventilation inhomogeneity associated with worse oxygenation.
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Affiliation(s)
- Jessica Thomson
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia .,Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Christoph M Rüegger
- Newborn Research, The Royal Women's Hospital, Parkville, Victoria, Australia.,Newborn Research, Department of Neonatology, University Hospital and University of Zürich, Zürich, Switzerland
| | - Elizabeth J Perkins
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | | | - Olivia Farrell
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia.,Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Louise S Owen
- Newborn Research, The Royal Women's Hospital, Parkville, Victoria, Australia
| | - David G Tingay
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia.,Neonatology, The Royal Children's Hospital Melbourne, Parkville, Victoria, Australia
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7
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Gaertner VD, Waldmann AD, Davis PG, Bassler D, Springer L, Thomson J, Tingay DG, Rüegger CM. Transmission of Oscillatory Volumes into the Preterm Lung during Noninvasive High-Frequency Ventilation. Am J Respir Crit Care Med 2021; 203:998-1005. [PMID: 33095994 DOI: 10.1164/rccm.202007-2701oc] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rationale: There is increasing evidence for a clinical benefit of noninvasive high-frequency oscillatory ventilation (nHFOV) in preterm infants. However, it is still unknown whether the generated oscillations are effectively transmitted to the alveoli.Objectives: To assess magnitude and regional distribution of oscillatory volumes (VOsc) at the lung level.Methods: In 30 prone preterm infants enrolled in a randomized crossover trial comparing nHFOV with nasal continuous positive airway pressure, electrical impedance tomography recordings were performed. During nHFOV, the smallest amplitude to achieve visible chest wall vibration was used, and the frequency was set at 8 hertz.Measurements and Main Results: Thirty consecutive breaths during artifact-free tidal ventilation were extracted for each of the 228 electrical impedance tomography recordings. After application of corresponding frequency filters, Vt and VOsc were calculated. There was a signal at 8 and 16 Hz during nHFOV, which was not detectable during nasal continuous positive airway pressure, corresponding to the set oscillatory frequency and its second harmonic. During nHFOV, the mean (SD) VOsc/Vt ratio was 0.20 (0.13). Oscillations were more likely to be transmitted to the non-gravity-dependent (mean difference [95% confidence interval], 0.041 [0.025-0.058]; P < 0.001) and right-sided lung (mean difference [95% confidence interval], 0.040 [0.019-0.061]; P < 0.001) when compared with spontaneous Vt.Conclusions: In preterm infants, VOsc during nHFOV are transmitted to the lung. Compared with the regional distribution of tidal breaths, oscillations preferentially reach the right and non-gravity-dependent lung. These data increase our understanding of the physiological processes underpinning nHFOV and may lead to further refinement of this novel technique.
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Affiliation(s)
- Vincent D Gaertner
- Newborn Research, Department of Neonatology, University Hospital and University of Zürich, Zürich, Switzerland
| | - Andreas D Waldmann
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
| | - Peter G Davis
- Newborn Research Centre and Neonatal Services, The Royal Women's Hospital, Melbourne, Victoria, Australia.,The University of Melbourne, Melbourne, Victoria, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Dirk Bassler
- Newborn Research, Department of Neonatology, University Hospital and University of Zürich, Zürich, Switzerland
| | - Laila Springer
- Department of Neonatology, University Children's Hospital, Tübingen, Germany; and
| | - Jessica Thomson
- The University of Melbourne, Melbourne, Victoria, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - David G Tingay
- The University of Melbourne, Melbourne, Victoria, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Neonatology, The Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Christoph M Rüegger
- Newborn Research, Department of Neonatology, University Hospital and University of Zürich, Zürich, Switzerland
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8
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Synchronized Inflations Generate Greater Gravity-Dependent Lung Ventilation in Neonates. J Pediatr 2021; 228:24-30.e10. [PMID: 32827530 DOI: 10.1016/j.jpeds.2020.08.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/05/2020] [Accepted: 08/14/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To describe the regional distribution patterns of tidal ventilation within the lung during mechanical ventilation that is synchronous or asynchronous with an infant's own breathing effort. STUDY DESIGN Intubated infants receiving synchronized mechanical ventilation at The Royal Children's Hospital neonatal intensive care unit were studied. During four 10-minute periods of routine care, regional distribution of tidal volume (VT; electrical impedance tomography), delivered pressure, and airway flow (Florian Respiratory Monitor) were measured for every inflation. Post hoc, each inflation was then classified as synchronous or asynchronous from video data of the ventilator screen, and the distribution of absolute VT and delivered ventilation characteristics determined. RESULTS In total, 2749 inflations (2462 synchronous) were analyzed in 19 infants; mean (SD) age 28 (30) days, gestational age 35 (5) weeks. Synchronous inflations were associated with a shorter respiratory cycle (P = .004) and more homogenous VT (center of ventilation) along the right (0%) to left (100%) lung plane; 45.3 (8.6)% vs 48.8 (9.4)% (uniform ventilation 46%). The gravity-dependent center of ventilation was a mean (95% CI) 2.1 (-0.5, 4.6)% toward the dependent lung during synchronous inflations. Tidal ventilation relative to anatomical lung size was more homogenous during synchronized inflations in the dependent lung. CONCLUSIONS Synchronous mechanical ventilator lung inflations generate more gravity-dependent lung ventilation and more uniform right-to-left ventilation than asynchronous inflations.
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9
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Pereira-Fantini PM, Pang B, Byars SG, Oakley RB, Perkins EJ, Dargaville PA, Davis PG, Nie S, Williamson NA, Ignjatovic V, Tingay DG. Preterm Lung Exhibits Distinct Spatiotemporal Proteome Expression at Initiation of Lung Injury. Am J Respir Cell Mol Biol 2020; 61:631-642. [PMID: 30995072 DOI: 10.1165/rcmb.2019-0084oc] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The development of regional lung injury in the preterm lung is not well understood. This study aimed to characterize time-dependent and regionally specific injury patterns associated with early ventilation of the preterm lung using a mass spectrometry-based proteomic approach. Preterm lambs delivered at 124-127 days gestation received 15 or 90 minutes of mechanical ventilation (positive end-expiratory pressure = 8 cm H2O, Vt = 6-8 ml/kg) and were compared with unventilated control lambs. At study completion, lung tissue was taken from standardized nondependent and dependent regions, and assessed for lung injury via histology, quantitative PCR, and proteomic analysis using Orbitrap-mass spectrometry. Ingenuity pathway analysis software was used to identify temporal and region-specific enrichments in pathways and functions. Apoptotic cell numbers were ninefold higher in nondependent lung at 15 and 90 minutes compared with controls, whereas proliferative cells were increased fourfold in the dependent lung at 90 minutes. The relative gene expression of lung injury markers was increased at 90 minutes in nondependent lung and unchanged in gravity-dependent lung. Within the proteome, the number of differentially expressed proteins was fourfold higher in the nondependent lung than the dependent lung. The number of differential proteins increased over time in both lung regions. A total of 95% of enriched canonical pathways and 94% of enriched cellular and molecular functions were identified only in nondependent lung tissue from the 90-minute ventilation group. In conclusion, complex injury pathways are initiated within the preterm lung after 15 minutes of ventilation and amplified by continuing ventilation. Injury development is region specific, with greater alterations within the proteome of nondependent lung.
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Affiliation(s)
| | | | - Sean G Byars
- Department of Clinical Pathology.,Melbourne Integrative Genomics
| | | | | | - Peter A Dargaville
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Peter G Davis
- Neonatal Research, and.,Department of Obstetrics and Gynaecology, and.,The Royal Women's Hospital, Parkville, Victoria, Australia; and
| | - Shuai Nie
- Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
| | | | - Vera Ignjatovic
- Haematology Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics
| | - David G Tingay
- Neonatal Research, and.,Department of Paediatrics.,Department of Neonatology, Royal Children's Hospital, Parkville, Victoria, Australia
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10
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Onland W, Hutten J, Miedema M, Bos LD, Brinkman P, Maitland-van der Zee AH, van Kaam AH. Precision Medicine in Neonates: Future Perspectives for the Lung. Front Pediatr 2020; 8:586061. [PMID: 33251166 PMCID: PMC7673376 DOI: 10.3389/fped.2020.586061] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/08/2020] [Indexed: 12/11/2022] Open
Abstract
Bronchopulmonary dysplasia (BPD) is the most common complication of pre-term birth with long lasting sequelae. Since its first description more than 50 years ago, many large randomized controlled trials have been conducted, aiming to improve evidence-based knowledge on the optimal strategies to prevent and treat BPD. However, most of these intervention studies have been performed on a population level without regard for the variation in clinical and biological diversity (e.g., gestational age, ethnicity, gender, or disease progression) between patients that is driven by the complex interaction of genetic pre-disposition and environmental exposures. Nevertheless, clinicians provide daily care such as lung protective interventions on an individual basis every day despite the fact that research supporting individualized or precision medicine for monitoring or treating pre-term lungs is immature. This narrative review summarizes four potential developments in pulmonary research that might facilitate the process of individualizing lung protective interventions to prevent development of BPD. Electrical impedance tomography and electromyography of the diaphragm are bedside monitoring tools to assess regional changes in lung volume and ventilation and spontaneous breathing effort, respectively. These non-invasive tools allow a more individualized optimization of invasive and non-invasive respiratory support. Investigation of the genomic variation in caffeine metabolism in pre-term infants can be used to optimize and individualize caffeine dosing regimens. Finally, volatile organic compound analysis in exhaled breath might accurately predict BPD at an early stage of the disease, enabling clinicians to initiate preventive strategies for BPD on an individual basis. Before these suggested diagnostic or monitoring tools can be implemented in daily practice and improve individualized patient care, future research should address and overcome their technical difficulties, perform extensive external validation and show their additional value in preventing BPD.
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Affiliation(s)
- Wes Onland
- Department of Neonatology, Amsterdam University Medical Centers, VU University Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, Netherlands
| | - Jeroen Hutten
- Department of Neonatology, Amsterdam University Medical Centers, VU University Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, Netherlands
| | - Martijn Miedema
- Department of Neonatology, Amsterdam University Medical Centers, VU University Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, Netherlands
| | - Lieuwe D Bos
- Department of Respiratory Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Paul Brinkman
- Department of Respiratory Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Anke H Maitland-van der Zee
- Department of Respiratory Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Anton H van Kaam
- Department of Neonatology, Amsterdam University Medical Centers, VU University Medical Center, Emma Children's Hospital, University of Amsterdam, Amsterdam, Netherlands
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11
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Miedema M, Adler A, McCall KE, Perkins EJ, van Kaam AH, Tingay DG. Electrical impedance tomography identifies a distinct change in regional phase angle delay pattern in ventilation filling immediately prior to a spontaneous pneumothorax. J Appl Physiol (1985) 2019; 127:707-712. [PMID: 31268827 DOI: 10.1152/japplphysiol.00973.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pneumothoraxes are common in preterm infants and are a major cause of morbidity. Early detection and treatment of pneumothoraxes are vital to minimize further respiratory compromise. Electrical impedance tomography (EIT) has been suggested as a method of rapidly detecting pneumothoraxes at the bedside. Our objective was to define the EIT-derived regional phase angle differences in filling characteristics before and during spontaneous pneumothoraxes in preterm lambs. Preterm lambs (124-127-day gestation) were ventilated with high-frequency oscillatory ventilation for 120 min. EIT data and cardiorespiratory parameters were monitored continuously and recorded for 3 min every 15 min. Six animals spontaneously developed a pneumothorax within a gravity-nondependent quadrant of the lung and were included for this analysis. Changes in end-expiratory lung impedance (EELI), ventilation, and phase angle delay were calculated in the four lung quadrants at the onset of the pneumothorax and 15 and 30 min prior. At the onset of the pneumothorax, all animals showed a clear increase in EELI in the affected lung quadrant. Fifteen and thirty minutes before the pneumothorax there was a significant phase angle delay between the nondependent and dependent lung. At 1 min before pneumothorax this phase angle delay was isolated just to the affected quadrant (nondependent). These findings are the first description of the events within the lung at initiation of a pneumothorax, demonstrating distinct predictive changes in air-filling characteristics before the occurrence of pneumothorax. This suggests that EIT may be able to accurately identify the onset of a pneumothorax.NEW & NOTEWORTHY In this article we describe for the first time predictive changes in electrical impedance tomography-based regional filling characteristics of the lung before the onset of a one-sided pneumothorax in six preterm lambs ventilated with high-frequency oscillatory ventilation. This can give clinicians bedside information to change treatment of preterm infants and prevent pneumothorax as life-threatening event from happening.
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Affiliation(s)
- Martijn Miedema
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Neonatology, Emma Children's Hospital, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Andy Adler
- Department of Systems and Computer Engineering, Carleton University, Ottawa, Ontario, Canada
| | - Karen E McCall
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Elizabeth J Perkins
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Anton H van Kaam
- Department of Neonatology, Emma Children's Hospital, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - David G Tingay
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Neonatology, Royal Children's Hospital, Melbourne, Victoria, Australia.,Department of Pediatrics, University of Melbourne, Melbourne, Victoria, Australia
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12
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Sophocleous L, Frerichs I, Miedema M, Kallio M, Papadouri T, Karaoli C, Becher T, Tingay DG, van Kaam AH, Bayford R, Waldmann AD. Clinical performance of a novel textile interface for neonatal chest electrical impedance tomography. Physiol Meas 2018. [DOI: 10.1088/1361-6579/aab513] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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13
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Abstract
Chronic respiratory morbidity is a common complication of premature birth, generally defined by the presence of bronchopulmonary dysplasia, both clinically and in trials of respiratory therapies. However, recent data have highlighted that bronchopulmonary dysplasia does not correlate with chronic respiratory morbidity in older children born preterm. Longitudinally evaluating pulmonary morbidity from early life through to childhood provides a more rational method of defining the continuum of chronic respiratory morbidity of prematurity, and offers new insights into the efficacy of neonatal respiratory interventions. The changing nature of preterm lung disease suggests that a multimodal approach using dynamic lung function assessment will be needed to assess the efficacy of a neonatal respiratory therapy and predict the long-term respiratory consequences of premature birth. Our aim is to review the literature regarding the long-term respiratory outcomes of neonatal respiratory strategies, the difficulties of assessing dynamic lung function in infants, and potential new solutions. Better measures are needed to predict chronic respiratory morbidity in survivors born prematurely http://ow.ly/1L3n30ihq9C
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14
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Farrell O, Perkins EJ, Black D, Miedema M, Paul JD, Pereira-Fantini PM, Tingay DG. Volume guaranteed? Accuracy of a volume-targeted ventilation mode in infants. Arch Dis Child Fetal Neonatal Ed 2018; 103:F120-F125. [PMID: 28659362 DOI: 10.1136/archdischild-2017-312640] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 04/28/2017] [Accepted: 05/01/2017] [Indexed: 11/03/2022]
Abstract
OBJECTIVES Volume-targeted ventilation (VTV) is widely used and may reduce lung injury, but this assumes the clinically set tidal volume (VTset) is accurately delivered. This prospective observational study aimed to determine the relationship between VTset, expiratory VT (VTe) and endotracheal tube leak in a modern neonatal -volume-targeted ventilator (VTV) and the resultant partial arterial pressure of carbon dioxide (PaCO2) relationship with and without VTV. DESIGN Continuous inflations were recorded for 24 hours in 100 infants, mean (SD) 34 (4) weeks gestation and 2483 (985) g birth weight, receiving synchronised mechanical ventilation (SLE5000, SLE, UK) with or without VTV and either the manufacturer's V4 (n=50) or newer V5 (n=50) VTV algorithm. The VTset, VTe and leak were determined for each inflation (maximum 90 000/infant). If PaCO2 was sampled (maximum of 2 per infant), this was compared with the average VTe data from the preceding 15 min. RESULTS A total of 7 497 137 inflations were analysed. With VTV enabled (77 infants), the VTset-VTe bias (95% CI) was 0.03 (-0.12 to 0.19) mL/kg, with a median of 80% of VTe being ±1.0 mL/kg of VTset. Endotracheal tube leak up to 30% influenced VTset-VTe bias with the V4 (r2=-0.64, p<0.0001; linear regression) but not V5 algorithm (r2=0.04, p=0.21). There was an inverse linear relationship between VTe and PaCO2 without VTV (r2=0.26, p=0.004), but not with VTV (r2=0.04, p=0.10), and less PaCO2 within 40-60 mm Hg, 53% versus 72%, relative risk (95% CI) 1.7 (1.0 to 2.9). CONCLUSION VTV was accurate and reliable even with moderate leak and PaCO2 more stable. VTV algorithm differences may exist in other devices.
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Affiliation(s)
- Olivia Farrell
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Elizabeth J Perkins
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Australia
| | - Don Black
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Australia
| | - Martijn Miedema
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Australia.,Neonatology, Academic Medical Centre, Amsterdam, The Netherlands
| | - Joel Don Paul
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Prue M Pereira-Fantini
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - David Gerald Tingay
- Neonatal Research, Murdoch Children's Research Institute, Melbourne, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Neonatology, Royal Children's Hospital, Melbourne, Australia
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15
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Miedema M, McCall KE, Perkins EJ, Sourial M, Böhm SH, Waldmann A, van Kaam AH, Tingay DG. First Real-Time Visualization of a Spontaneous Pneumothorax Developing in a Preterm Lamb Using Electrical Impedance Tomography. Am J Respir Crit Care Med 2017; 194:116-8. [PMID: 27367888 DOI: 10.1164/rccm.201602-0292le] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Martijn Miedema
- 1 Murdoch Children's Research Institute Melbourne, Australia.,2 Academic Medical Centre Amsterdam Amsterdam, the Netherlands
| | - Karen E McCall
- 1 Murdoch Children's Research Institute Melbourne, Australia.,3 University College Dublin Dublin, Ireland
| | | | - Magdy Sourial
- 1 Murdoch Children's Research Institute Melbourne, Australia
| | | | | | | | - David G Tingay
- 1 Murdoch Children's Research Institute Melbourne, Australia.,5 Royal Women's Hospital Melbourne, Australia.,6 Royal Children's Hospital Melbourne, Australia and.,7 University of Melbourne Melbourne, Australia
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16
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Bhatia R, Davis PG, Tingay DG. Regional Volume Characteristics of the Preterm Infant Receiving First Intention Continuous Positive Airway Pressure. J Pediatr 2017; 187:80-88.e2. [PMID: 28545875 DOI: 10.1016/j.jpeds.2017.04.046] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/27/2017] [Accepted: 04/21/2017] [Indexed: 01/19/2023]
Abstract
OBJECTIVE To determine whether applying nasal continuous positive airway pressure (CPAP) using systematic changes in continuous distending pressure (CDP) results in a quasi-static pressure-volume relationship in very preterm infants receiving first intention CPAP in the first 12-18 hours of life. STUDY DESIGN Twenty infants at <32 weeks' gestation with mild respiratory distress syndrome (RDS) managed exclusively with nasal CPAP had CDP increased from 5 to 8 to 10 cmH2O, and then decreased to 8 cmH2O and returned to baseline CDP. Each CDP was maintained for 20 min. At each CDP, relative impedance change in end-expiratory thoracic volume (ΔZEEV) and tidal volume (ΔZVT) were measured using electrical impedance tomography. Esophageal pressure (Poes) was measured as a proxy for intrapleural pressure to determine transpulmonary pressure (Ptp). RESULTS Overall, there was a relationship between Ptp and global ΔZEEV representing the pressure-volume relationship in the lungs. There were regional variations in ΔZEEV, with 13 infants exhibiting hysteresis with the greatest gains in EEV and tidal volume in the dependent lung with no hemodynamic compromise. Seven infants did not demonstrate hysteresis during decremental CDP changes. CONCLUSION It was possible to define a pressure-volume relationship of the lung and demonstrate reversal of atelectasis by systematically manipulating CDP in most very preterm infants with mild RDS. This suggests that CDP manipulation can be used to optimize the volume state of the preterm lung.
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Affiliation(s)
- Risha Bhatia
- Newborn Research, The Royal Women's Hospital, Melbourne, Australia; Neonatal Research, Murdoch Childrens Research Institute, Melbourne, Australia; The University of Melbourne, Melbourne, Australia; Monash Newborn, Monash Children's Hospital, Melbourne, Australia.
| | - Peter G Davis
- Newborn Research, The Royal Women's Hospital, Melbourne, Australia; Neonatal Research, Murdoch Childrens Research Institute, Melbourne, Australia; The University of Melbourne, Melbourne, Australia
| | - David G Tingay
- Newborn Research, The Royal Women's Hospital, Melbourne, Australia; Neonatal Research, Murdoch Childrens Research Institute, Melbourne, Australia; The University of Melbourne, Melbourne, Australia; Department of Neonatology, The Royal Children's Hospital, Melbourne, Australia
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17
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Abouzeid T, Perkins EJ, Pereira-Fantini PM, Rajapaksa A, Suka A, Tingay DG. Tidal Volume Delivery during the Anesthetic Management of Neonates Is Variable. J Pediatr 2017; 184:51-56.e3. [PMID: 28410092 DOI: 10.1016/j.jpeds.2017.01.074] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 01/03/2017] [Accepted: 01/31/2017] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To describe expiratory tidal volume (VT) during routine anesthetic management of neonates at a single tertiary neonatal surgical center, as well as the proportion of VT values within the range of 4.0-8.0 mL/kg. STUDY DESIGN A total of 26 neonates needing surgery under general anesthesia were studied, of whom 18 were intubated postoperatively. VT was measured continuously during normal clinical care using a dedicated neonatal respiratory function monitor (RFM), with clinicians blinded to values. VT, pressure, and cardiorespiratory variables were recorded regularly while intubated intraoperatively, during postoperative transport, and for 15 minutes after returning to the neonatal intensive care unit (NICU). In addition, paired VT values from the anesthetic machine were documented intraoperatively. RESULTS A total of 2597 VT measures were recorded from 26 neonates. Intraoperative and postoperative transport expiratory VT values were highly variable compared with the NICU VT (P < .0001, Kruskal-Wallis test), with 51% of inflations outside the 4.0-8.0 mL/kg range (35% and 38% of VT >8.0 mL/kg, respectively), compared with 29% in the NICU (P < .001, χ2 test). The use of a flow-inflating bag resulted in a median (range) VT of 8.5 mL/kg (range, 5.3-11.4 mL/kg) vs 5.6 ml/kg (range, 4.3-7.9 mL/kg) using a Neopuff T-piece system (P < .0001, Mann-Whitney U test). The mean anesthetic machine expiratory VT was 3.2 mL/kg (95% CI, -4.5 to 10.8 mL/kg) above RFM. CONCLUSIONS VT is highly variable during the anesthetic care of neonates, and potentially injurious VT is frequently delivered; thus, we suggest close VT monitoring using a dedicated neonatal RFM.
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Affiliation(s)
- Thanaa Abouzeid
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia; Department of Pediatrics, University of Melbourne, Melbourne, Australia
| | - Elizabeth J Perkins
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | | | - Anushi Rajapaksa
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia; Department of Pediatrics, University of Melbourne, Melbourne, Australia
| | - Asha Suka
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia; Department of Pediatrics, University of Melbourne, Melbourne, Australia
| | - David G Tingay
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia; Department of Pediatrics, University of Melbourne, Melbourne, Australia; Neonatology, The Royal Children's Hospital, Parkville, Australia.
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18
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Miedema M, Waldmann A, McCall KE, Böhm SH, van Kaam AH, Tingay DG. Individualized Multiplanar Electrical Impedance Tomography in Infants to Optimize Lung Monitoring. Am J Respir Crit Care Med 2017; 195:536-538. [DOI: 10.1164/rccm.201607-1370le] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Martijn Miedema
- Murdoch Children’s Research InstituteMelbourne, Australia
- Academic Medical Centre AmsterdamAmsterdam, the Netherlands
| | | | - Karen E. McCall
- Murdoch Children’s Research InstituteMelbourne, Australia
- University College DublinDublin, Ireland
| | | | | | - David G. Tingay
- Murdoch Children’s Research InstituteMelbourne, Australia
- Royal Children’s HospitalMelbourne, Australiaand
- University of MelbourneMelbourne, Australia
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19
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Frerichs I, Amato MBP, van Kaam AH, Tingay DG, Zhao Z, Grychtol B, Bodenstein M, Gagnon H, Böhm SH, Teschner E, Stenqvist O, Mauri T, Torsani V, Camporota L, Schibler A, Wolf GK, Gommers D, Leonhardt S, Adler A. Chest electrical impedance tomography examination, data analysis, terminology, clinical use and recommendations: consensus statement of the TRanslational EIT developmeNt stuDy group. Thorax 2016; 72:83-93. [PMID: 27596161 PMCID: PMC5329047 DOI: 10.1136/thoraxjnl-2016-208357] [Citation(s) in RCA: 474] [Impact Index Per Article: 59.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 07/12/2016] [Accepted: 07/16/2016] [Indexed: 11/04/2022]
Abstract
Electrical impedance tomography (EIT) has undergone 30 years of development. Functional chest examinations with this technology are considered clinically relevant, especially for monitoring regional lung ventilation in mechanically ventilated patients and for regional pulmonary function testing in patients with chronic lung diseases. As EIT becomes an established medical technology, it requires consensus examination, nomenclature, data analysis and interpretation schemes. Such consensus is needed to compare, understand and reproduce study findings from and among different research groups, to enable large clinical trials and, ultimately, routine clinical use. Recommendations of how EIT findings can be applied to generate diagnoses and impact clinical decision-making and therapy planning are required. This consensus paper was prepared by an international working group, collaborating on the clinical promotion of EIT called TRanslational EIT developmeNt stuDy group. It addresses the stated needs by providing (1) a new classification of core processes involved in chest EIT examinations and data analysis, (2) focus on clinical applications with structured reviews and outlooks (separately for adult and neonatal/paediatric patients), (3) a structured framework to categorise and understand the relationships among analysis approaches and their clinical roles, (4) consensus, unified terminology with clinical user-friendly definitions and explanations, (5) a review of all major work in thoracic EIT and (6) recommendations for future development (193 pages of online supplements systematically linked with the chief sections of the main document). We expect this information to be useful for clinicians and researchers working with EIT, as well as for industry producers of this technology.
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Affiliation(s)
- Inéz Frerichs
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Marcelo B P Amato
- Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Anton H van Kaam
- Department of Neonatology, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
| | - David G Tingay
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Victoria, Australia
| | - Zhanqi Zhao
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Bartłomiej Grychtol
- Fraunhofer Project Group for Automation in Medicine and Biotechnology PAMB, Mannheim, Germany
| | - Marc Bodenstein
- Department of Anesthesiology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Hervé Gagnon
- Department of Systems and Computer Engineering, Carleton University, Ottawa, Ontario, Canada
| | | | | | - Ola Stenqvist
- Department of Anesthesiology and Intensive Care Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Tommaso Mauri
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Vinicius Torsani
- Pulmonary Division, Heart Institute (InCor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Luigi Camporota
- Department of Adult Critical Care, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Andreas Schibler
- Paediatric Critical Care Research Group, Mater Research University of Queensland, South Brisbane, Australia
| | - Gerhard K Wolf
- Children's Hospital Traunstein, Ludwig Maximilian's University, Munich, Germany
| | - Diederik Gommers
- Department of Adult Intensive Care, Erasmus MC, Rotterdam, The Netherlands
| | - Steffen Leonhardt
- Philips Chair for Medical Information Technology, Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
| | - Andy Adler
- Department of Systems and Computer Engineering, Carleton University, Ottawa, Ontario, Canada
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20
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Tingay DG, Lavizzari A, Zonneveld CEE, Rajapaksa A, Zannin E, Perkins E, Black D, Sourial M, Dellacà RL, Mosca F, Adler A, Grychtol B, Frerichs I, Davis PG. An individualized approach to sustained inflation duration at birth improves outcomes in newborn preterm lambs. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1138-49. [DOI: 10.1152/ajplung.00277.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 09/17/2015] [Indexed: 01/18/2023] Open
Abstract
A sustained first inflation (SI) at birth may aid lung liquid clearance and aeration, but the impact of SI duration relative to the volume-response of the lung is poorly understood. We compared three SI strategies: 1) variable duration defined by attaining volume equilibrium using real-time electrical impedance tomography (EIT; SIplat); 2) 30 s beyond equilibrium (SIlong); 3) short 30-s SI (SI30); and 4) positive pressure ventilation without SI (no-SI) on spatiotemporal aeration and ventilation (EIT), gas exchange, lung mechanics, and regional early markers of injury in preterm lambs. Fifty-nine fetal-instrumented lambs were ventilated for 60 min after applying the allocated first inflation strategy. At study completion molecular and histological markers of lung injury were analyzed. The time to SI volume equilibrium, and resultant volume, were highly variable; mean (SD) 55 (34) s, coefficient of variability 59%. SIplat and SIlong resulted in better lung mechanics, gas exchange and lower ventilator settings than both no-SI and SI30. At 60 min, alveolar-arterial difference in oxygen was a mean (95% confidence interval) 130 (13, 249) higher in SI30 vs. SIlong group (two-way ANOVA). These differences were due to better spatiotemporal aeration and tidal ventilation, although all groups showed redistribution of aeration towards the nondependent lung by 60 min. Histological lung injury scores mirrored spatiotemporal change in aeration and were greatest in SI30 group ( P < 0.01, Kruskal-Wallis test). An individualized volume-response approach to SI was effective in optimizing aeration, homogeneous tidal ventilation, and respiratory outcomes, while an inadequate SI duration had no benefit over positive pressure ventilation alone.
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Affiliation(s)
- David G. Tingay
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
- Neonatology, The Royal Children's Hospital, Parkville, Australia
- Neonatal Research, The Royal Women's Hospital, Parkville, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Anna Lavizzari
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
- Neonatal Intensive Care Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda, Ospedale Maggiore Policlinico-Università Degli Studi di Milano, Milano, Italy
| | | | - Anushi Rajapaksa
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Emanuela Zannin
- Laboratorio di Tecnologie Biomediche, Dipartimento di Elettronica, Informazione e Ingegneria Biomedica-DEIB, Politecnico di Milano University, Milano, Italy
| | - Elizabeth Perkins
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Don Black
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Magdy Sourial
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
| | - Raffaele L. Dellacà
- Laboratorio di Tecnologie Biomediche, Dipartimento di Elettronica, Informazione e Ingegneria Biomedica-DEIB, Politecnico di Milano University, Milano, Italy
| | - Fabio Mosca
- Neonatal Intensive Care Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca' Granda, Ospedale Maggiore Policlinico-Università Degli Studi di Milano, Milano, Italy
| | - Andy Adler
- Systems and Computer Engineering, Carleton University, Ottawa, Canada
| | - Bartłomiej Grychtol
- Fraunhofer Project Group for Automation in Medicine and Biotechnology, Mannheim, Germany
| | - Inéz Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany; and
| | - Peter G. Davis
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
- Neonatal Research, The Royal Women's Hospital, Parkville, Australia
- Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Australia
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21
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Gong B, Krueger-Ziolek S, Moeller K, Schullcke B, Zhao Z. Electrical impedance tomography: functional lung imaging on its way to clinical practice? Expert Rev Respir Med 2015; 9:721-37. [DOI: 10.1586/17476348.2015.1103650] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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Arrindell EL, Krishnan R, van der Merwe M, Caminita F, Howard SC, Zhang J, Buddington RK. Lung volume recruitment in a preterm pig model of lung immaturity. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1088-92. [PMID: 26408557 DOI: 10.1152/ajplung.00292.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 09/17/2015] [Indexed: 12/22/2022] Open
Abstract
A translational preterm pig model analogous to infants born at 28 wk of gestation revealed that continuous positive airway pressure results in limited lung recruitment but does not prevent respiratory distress syndrome, whereas assist-control + volume guarantee (AC+VG) ventilation improves recruitment but can cause injury, highlighting the need for improved ventilation strategies. We determined whether airway pressure release ventilation (APRV) can be used to recruit the immature lungs of preterm pigs without injury. Spontaneously breathing pigs delivered at 89% of term (model for 28-wk infants) were randomized to 24 h of APRV (n = 9) vs. AC+VG with a tidal volume of 5 ml/kg (n = 10). Control pigs (n = 36) were provided with supplemental oxygen by an open mask. Nutrition and fluid support was provided throughout the 24-h period. All pigs supported with APRV and AC+VG survived 24 h, compared with 62% of control pigs. APRV resulted in improved lung volume recruitment compared with AC+VG based on radiographs, lower Pco2 levels (44 ± 2.9 vs. 53 ± 2.7 mmHg, P = 0.009) and lower inspired oxygen fraction requirements (36 ± 6 vs. 44 ± 11%, P < 0.001), and higher oxygenation index (5.1 ± 1.5 vs. 2.9 ± 1.1, P = 0.001). There were no differences between APRV and AC+VG pigs for heart rate, ratio of wet to dry lung mass, proinflammatory cytokines, or histopathological markers of lung injury. Lung protective ventilation with APRV improved recruitment of alveoli of preterm lungs, enhanced development and maintenance of functional residual capacity without injury, and improved clinical outcomes relative to AC+VG. Long-term consequences of lung volume recruitment by using APRV should be evaluated.
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Affiliation(s)
- Esmond L Arrindell
- Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Ramesh Krishnan
- Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | | | | | - Scott C Howard
- School of Health Studies, University of Memphis, Memphis, Tennessee
| | - Jie Zhang
- Pathology, University of Tennessee Health Science Center, Memphis, Tennessee
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Vogt B, Falkenberg C, Weiler N, Frerichs I. Pulmonary function testing in children and infants. Physiol Meas 2014; 35:R59-90. [PMID: 24557323 DOI: 10.1088/0967-3334/35/3/r59] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Pulmonary function testing is performed in children and infants with the aim of documenting lung development with age and making diagnoses of lung diseases. In children and infants with an established lung disease, pulmonary function is tested to assess the disease progression and the efficacy of therapy. It is difficult to carry out the measurements in this age group without disturbances, so obtaining results of good quality and reproducibility is challenging. Young children are often uncooperative during the examinations. This is partly related to their young age but also due to the long testing duration and the unpopular equipment. We address a variety of examination techniques for lung function assessment in children and infants in this review. We describe the measuring principles, examination procedures, clinical findings and their interpretation, as well as advantages and limitations of these methods. The comparability between devices and centres as well as the availability of reference values are still considered a challenge in many of these techniques. In recent years, new technologies have emerged allowing the assessment of lung function not only on the global level but also on the regional level. This opens new possibilities for detecting regional lung function heterogeneity that might lead to a better understanding of respiratory pathophysiology in children.
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Affiliation(s)
- B Vogt
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany
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Polglase GR, Tingay DG, Bhatia R, Berry CA, Kopotic RJ, Kopotic CP, Song Y, Szyld E, Jobe AH, Pillow JJ. Pressure- versus volume-limited sustained inflations at resuscitation of premature newborn lambs. BMC Pediatr 2014; 14:43. [PMID: 24529320 PMCID: PMC3937019 DOI: 10.1186/1471-2431-14-43] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 02/05/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Sustained inflations (SI) are advocated for the rapid establishment of FRC after birth in preterm and term infants requiring resuscitation. However, the most appropriate way to deliver a SI is poorly understood. We investigated whether a volume-limited SI improved the establishment of FRC and ventilation homogeneity and reduced lung inflammation/injury compared to a pressure-limited SI. METHODS 131 d gestation lambs were resuscitated with either: i) pressure-limited SI (PressSI: 0-40 cmH2O over 5 s, maintained until 20 s); or ii) volume-limited SI (VolSI: 0-15 mL/kg over 5 s, maintained until 20 s). Following the SI, all lambs were ventilated using volume-controlled ventilation (7 mL/kg tidal volume) for 15 min. Lung mechanics, regional ventilation distribution (electrical impedance tomography), cerebral tissue oxygenation index (near infrared spectroscopy), arterial pressures and blood gas values were recorded regularly. Pressure-volume curves were performed in-situ post-mortem and early markers of lung injury were assessed. RESULTS Compared to a pressure-limited SI, a volume-limited SI had increased pressure variability but reduced volume variability. Each SI strategy achieved similar end-inflation lung volumes and regional ventilation homogeneity. Volume-limited SI increased heart-rate and arterial pressure faster than pressure-limited SI lambs, but no differences were observed after 30 s. Volume-limited SI had increased arterial-alveolar oxygen difference due to higher FiO2 at 15 min (p = 0.01 and p = 0.02 respectively). No other inter-group differences in arterial or cerebral oxygenation, blood pressures or early markers of lung injury were evident. CONCLUSION With the exception of inferior oxygenation, a sustained inflation targeting delivery to preterm lambs of 15 mL/kg volume by 5 s did not influence physiological variables or early markers of lung inflammation and injury at 15 min compared to a standard pressure-limited sustained inflation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Jane J Pillow
- Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, Australia.
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Effect of sustained inflation vs. stepwise PEEP strategy at birth on gas exchange and lung mechanics in preterm lambs. Pediatr Res 2014; 75:288-94. [PMID: 24257321 DOI: 10.1038/pr.2013.218] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 06/27/2013] [Indexed: 11/08/2022]
Abstract
BACKGROUND Sustained inflation (SI) at birth facilitates establishment of functional residual capacity (FRC) in the preterm lung, but the ideal lung recruitment strategy is unclear. We have compared the effect of SI and a stepwise positive end-expiratory pressure (PEEP; SEP) strategy in a preterm model. METHODS 127 d gestation lambs received either 20-s SI (n = 9) or 2 cmH2O stepwise PEEP increases to 20 cmH2O every 10 inflations, and then decreases to 6 cmH2O (n = 10). Ventilation continued for 70 min, with surfactant administered at 10 min. Alveolar-arterial oxygen gradient (AaDO2), compliance (C(dyn)), end-expiratory thoracic volume (EEVRIP; respiratory inductive plethysmography), and EEV and C(dyn) in the gravity-dependent and nondependent hemithoraces (electrical impedance tomography) were measured throughout. Early mRNA markers of lung injury were analyzed using quantitative real-time PCR. RESULTS From 15 min of life, AaDO2 was lower in SEP group (P < 0.005; two-way ANOVA). SEP resulted in higher and more homogeneous C(dyn) (P < 0.0001). Mean (SD) EEVRIP at 5 min was 18 (9) ml/kg and 6 (5) ml/kg following SEP and SI, respectively (P = 0.021; Bonferroni posttest); this difference was due to a greater nondependent hemithorax EEV. There was no difference in markers of lung injury. CONCLUSION An SEP at birth improved gas exchange, lung mechanics, and EEV, without increasing lung injury, compared to the SI strategy used.
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Tingay DG, Wallace MJ, Bhatia R, Schmölzer GM, Zahra VA, Dolan MJ, Hooper SB, Davis PG. Surfactant before the first inflation at birth improves spatial distribution of ventilation and reduces lung injury in preterm lambs. J Appl Physiol (1985) 2013; 116:251-8. [PMID: 24356523 DOI: 10.1152/japplphysiol.01142.2013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The interrelationship between the role of surfactant and a sustained inflation (SI) to aid ex utero transition of the preterm lung is unknown. We compared the effect of surfactant administered before and after an initial SI on gas exchange, lung mechanics, spatial distribution of ventilation, and lung injury in preterm lambs. Gestational-age lambs (127 days; 9 per group) received 100 mg/kg of a surfactant (Curosurf) either prior (Surf+SI) or 10 min after birth (SI+Surf). At birth, a 20-s, 35 cmH2O SI was applied, followed by 70 min of positive pressure ventilation. Oxygenation, carbon dioxide removal, respiratory system compliance, end-expiratory thoracic volume (via respiratory inductive plethysmography), and distribution of end-expiratory volume and ventilation (via electrical impedance tomography) were measured throughout. Early markers of lung injury were analyzed using quantitative RT-PCR. During the first 15 min, oxygenation, carbon dioxide removal, and compliance were better in the Surf+SI group (all P < 0.05). End-expiratory volume on completion of the sustained inflation was higher in the Surf+SI group than the SI+Surf group; 11 ± 1 ml/kg vs. 7 ± 1 ml/kg (mean ± SE) (P = 0.043; t-test), but was not different at later time points. Although neither achieved homogenous aeration, spatial ventilation was more uniform in the Surf+SI group throughout; 50.1 ± 10.9% of total ventilation in the left hemithorax at 70 min vs. 42.6 ± 11.1% in the SI+Surf group. Surf+SI resulted in lower mRNA levels of CYR61 and EGR1 compared with SI+Surf (P < 0.001, one-way ANOVA). Surfactant status of the fetal preterm lung at birth influences the mechanical and injury response to a sustained inflation and ventilation by changing surface tension of the air/fluid interface.
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Affiliation(s)
- David G Tingay
- Neonatal Research, Murdoch Childrens Research Institute, Parkville, Australia
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Schmölzer GM, Bhatia R, Davis PG, Tingay DG. A comparison of different bedside techniques to determine endotracheal tube position in a neonatal piglet model. Pediatr Pulmonol 2013; 48:138-45. [PMID: 22615185 DOI: 10.1002/ppul.22580] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 03/06/2012] [Indexed: 12/22/2022]
Abstract
RATIONALE Endotracheal tube (ETT) malposition is common and an increasing number of non-invasive techniques to aid rapid identification of tube position are available. Electrical impedance tomography (EIT) is advocated as a tool to monitor ventilation. OBJECTIVE This study aimed to compare EIT with five other non-invasive techniques for identifying ETT position in a piglet model. METHODOLOGY Six saline lavage surfactant-depleted piglets were studied. Periods of ventilation with ETT placed in the oesophagus or a main bronchus (MB) were compared with an appropriately placed mid-tracheal ETT. Colorimetric end-tidal CO(2) (Pedi-Cap®), SpO(2) and heart rate, tidal volume (${\rm V}_{{\rm T}_{{\rm ao}} } $) using a hot-wire anemometer at the airway opening, tidal volume using respiratory inductive plethysmography (${\rm V}_{{\rm T}_{{\rm RIP}} } $) and regional tidal ventilation within each hemithorax (EIT) were measured. RESULTS Oesophageal ventilation: Pedi-Cap® demonstrated absence of color change. ${\rm V}_{{\rm T}_{{\rm ao}} } $, ${\rm V}_{{\rm T}_{{\rm RIP}} } $, and EIT correctly demonstrated no tidal ventilation. SpO(2) decreased from mean (SD) 96 (2)% to 74 (12)% (P < 0.05; Bonferroni post-test), without heart rate change. MB ventilation: SpO(2) , heart rate and Pedi-Cap® were unchanged compared with mid-tracheal position. ${\rm V}_{{\rm T}_{{\rm ao}} } $ and ${\rm V}_{{\rm T}_{{\rm RIP}} } $ decreased from a mean (SD) 10.8 (5.6) ml/kg and 14.6 (6.2) ml/kg to 5.5 (1.9) ml/kg and 6.4 (2.6) ml/kg (both P < 0.05; Bonferroni post-test). EIT identified the side of MB ventilation, with a mean (SD) 95 (3)% reduction in tidal volume in the unventilated lung. CONCLUSIONS EIT not only correctly identified oesophageal ventilation but also localized the side of MB ventilation. At present, no one technique is without limitations and clinicians should utilize a combination in addition to clinical judgement.
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Affiliation(s)
- Georg M Schmölzer
- Neonatal Research, Murdoch Childrens Research Institute, Melbourne, Australia.
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Hough JL, Johnston L, Brauer S, Woodgate P, Schibler A. Effect of body position on ventilation distribution in ventilated preterm infants. Pediatr Crit Care Med 2013; 14:171-7. [PMID: 23314179 DOI: 10.1097/pcc.0b013e31826e708a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
RATIONALE Positioning is considered vital to the maintenance of good lung ventilation by optimizing oxygen transport and gas exchange in ventilated premature infants. Previous studies suggest that the prone position is advantageous; however, no data exist on regional ventilation distribution for this age group. OBJECTIVES To investigate the effect of body position on regional ventilation distribution in ventilated and nonventilated preterm infants using electrical impedance tomography. DESIGN Randomized crossover study design. SETTING Neonatal ICU. PATIENTS A total of 24 ventilated preterm infants were compared with six spontaneously breathing preterm infants. INTERVENTIONS Random assignment of the order of the positions supine, prone, and quarter prone. MEASUREMENTS AND MAIN RESULTS Ventilation distribution was measured with regional impedance amplitudes and global inhomogeneity indices using electrical impedance tomography. In the spontaneously breathing infants, regional impedance amplitudes were increased in the posterior compared with the anterior lung (p < 0.01) and in the right compared with the left lung (p = 0.03). No differences were found in the ventilated infants. Ventilation was more inhomogeneous in the ventilated compared with the healthy infants (p < 0.01). Assessment of temporal regional lung filling showed that the posterior lung filled earlier than the anterior lung in the spontaneously breathing infants (p < 0.02) whereas in the in the ventilated infants the right lung filled before the left lung (p < 0.01). CONCLUSIONS In contrast to previous studies showing that ventilation is distributed to the nondependent lung in infants and children, this study shows that gravity has little effect on regional ventilation distribution.
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Affiliation(s)
- Judith L Hough
- Critical Care of the Newborn Program, Mater Medical Research Institute, South Brisbane, QLD, Australia.
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Rossi FDS, Yagui ACZ, Haddad LB, Deutsch AD, Rebello CM. Electrical impedance tomography to evaluate air distribution prior to extubation in very-low-birth-weight infants: a feasibility study. Clinics (Sao Paulo) 2013; 68:345-50. [PMID: 23644854 PMCID: PMC3611755 DOI: 10.6061/clinics/2013(03)oa10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 11/18/2012] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES Nasal continuous positive airway pressure is used as a standard of care after extubation in very-low-birth-weight infants. A pressure of 5 cmH2O is usually applied regardless of individual differences in lung compliance. Current methods for evaluation of lung compliance and air distribution in the lungs are thus imprecise for preterm infants. This study used electrical impedance tomography to determine the feasibility of evaluating the positive end-expiratory pressure level associated with a more homogeneous air distribution within the lungs before extubation. METHODS Ventilation homogeneity was defined by electrical impedance tomography as the ratio of ventilation between dependent and non-dependent lung areas. The best ventilation homogeneity was achieved when this ratio was equal to 1. Just before extubation, decremental expiratory pressure levels were applied (8, 7, 6 and 5 cmH(2)0; 3 minutes each step), and the pressure that determined the best ventilation homogeneity was defined as the best positive end-expiratory pressure. RESULTS The best positive end-expiratory pressure value was 6.3 ± 1.1 cmH(2)0, and the mean continuous positive airway pressure applied after extubation was 5.2 ± 0.4 cmH(2)0 (p = 0.002). The extubation failure rate was 21.4%. X-Ray and blood gases after extubation were also checked. CONCLUSION This study demonstrates that electrical impedance tomography can be safely and successfully used in patients ready for extubation to suggest the best ventilation homogeneity, which is influenced by the level of expiratory pressure applied. In this feasibility study, the best lung compliance was found with pressure levels higher than the continuous positive airway pressure levels that are usually applied for routine extubation.
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Affiliation(s)
- Felipe de Souza Rossi
- Departamento Materno-infantil, Hospital Israelita Albert Einstein, São Paulo, SP, Brazil
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Vogt B, Pulletz S, Elke G, Zhao Z, Zabel P, Weiler N, Frerichs I. Spatial and temporal heterogeneity of regional lung ventilation determined by electrical impedance tomography during pulmonary function testing. J Appl Physiol (1985) 2012; 113:1154-61. [PMID: 22898553 DOI: 10.1152/japplphysiol.01630.2011] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electrical impedance tomography (EIT) is a functional imaging modality capable of tracing continuously regional pulmonary gas volume changes. The aim of our study was to determine if EIT was able to assess spatial and temporal heterogeneity of ventilation during pulmonary function testing in 14 young (37 ± 10 yr, mean age ± SD) and 12 elderly (71 ± 9 yr) subjects without lung disease and in 33 patients with chronic obstructive pulmonary disease (71 ± 9 yr). EIT and spirometry examinations were performed during tidal breathing and a forced vital capacity (FVC) maneuver preceded by full inspiration to total lung capacity. Regional inspiratory vital capacity (IVC); FVC; forced expiratory volume in 1 s (FEV(1)); FEV(1)/FVC; times required to expire 25%, 50%, 75%, and 90% of FVC (t(25), t(50), t(75), t(90)); and tidal volume (V(T)) were determined in 912 EIT image pixels in the chest cross section. Coefficients of variation (CV) were calculated from all pixel values of IVC, FVC, FEV(1), and V(T) to characterize the ventilation heterogeneity. The highest values were found in patients, and no differences existed between the healthy young and elderly subjects. Receiver-operating characteristics curves showed that CV of regional IVC, FVC, FEV(1), and V(T) discriminated the young and elderly subjects from the patients. Frequency distributions of pixel FEV(1)/FVC, t(25), t(50), t(75), and t(90) identified the highest ventilation heterogeneity in patients but distinguished also the healthy young from the elderly subjects. These results indicate that EIT may provide additional information during pulmonary function testing and identify pathologic and age-related spatial and temporal heterogeneity of regional lung function.
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Affiliation(s)
- Barbara Vogt
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Arnold-Heller-Strasse 3, Kiel, Germany
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Bhatia R, Schmölzer GM, Davis PG, Tingay DG. Electrical impedance tomography can rapidly detect small pneumothoraces in surfactant-depleted piglets. Intensive Care Med 2011; 38:308-15. [DOI: 10.1007/s00134-011-2421-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 10/18/2011] [Indexed: 10/15/2022]
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