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Dassios T, Williams EE, Kaltsogianni O, Greenough A. Permissive hypercapnia and oxygenation impairment in premature ventilated infants. Respir Physiol Neurobiol 2023; 317:104144. [PMID: 37647975 DOI: 10.1016/j.resp.2023.104144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/04/2023] [Accepted: 08/26/2023] [Indexed: 09/01/2023]
Abstract
AIM In permissive hypercapnia high levels of carbon dioxide (CO2) are tolerated in ventilated preterm infants to minimise lung injury, but hypercapnia could directly impair oxygenation. We aimed to quantify the association of elevated CO2 with oxygenation impairment in preterm infants by measuring the right-to-left shunt and the ventilation/perfusion (VA/Q) ratio. METHODS Pre-existing datasets from preterm infants during the acute phase of respiratory distress syndrome or with evolving or established bronchopulmonary dysplasia were analysed. Non-invasive paired measurements of the fraction of inspired oxygen (FIO2) and transcutaneous oxygen saturation (SpO2) were used to calculate the degree of right-to-left shunt, right shift of the FIO2 versus SpO2 curve and the VA/Q. RESULTS A total of 75 infants (43 male) with a median (IQR) gestational age of 26.4 (24.7-27.7) weeks were studied at 7 (2-31) days. Thirty-six infants (48 %) had an arterial partial pressure of CO2 (PaCO2) above 6 kPa. The PaCO2 was independently associated with the right shift of the curve [adjusted p < 0.001, unstandardised coefficient; 2.26, 95 % CI: 1.51-2.95] and the right-to-left shunt [adjusted p = 0.016, unstandardised coefficient; 1.86, 95 % CI: 0.36-3.36] after adjusting for confounders. An increase of the PaCO2 from 5 to 8 kPa, corresponded to a right shift of the curve of 20.2 kPa or a decrease in the VA/Q from 0.66 to 0.24. CONCLUSIONS Increased carbon dioxide levels were significantly associated with impaired oxygenation in preterm infants with respiratory distress syndrome or bronchopulmonary dysplasia.
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Affiliation(s)
- Theodore Dassios
- Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, UK; Neonatal Intensive Care Unit, University of Patras, Patras, Greece.
| | - Emma E Williams
- Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, UK
| | - Ourania Kaltsogianni
- Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, UK
| | - Anne Greenough
- Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, UK
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Williams EE, Gareth Jones J, McCurnin D, Rüdiger M, Nanjundappa M, Greenough A, Dassios T. Functional morphometry: non-invasive estimation of the alveolar surface area in extremely preterm infants. Pediatr Res 2023; 94:1707-1713. [PMID: 37045946 PMCID: PMC10624622 DOI: 10.1038/s41390-023-02597-z] [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: 10/04/2022] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 04/14/2023]
Abstract
BACKGROUND The main pathophysiologic characteristic of chronic respiratory disease following extremely premature birth is arrested alveolar growth, which translates to a smaller alveolar surface area (SA). We aimed to use non-invasive measurements to estimate the SA in extremely preterm infants. METHODS Paired measurements of the fraction of inspired oxygen and transcutaneous oxygen saturation were used to calculate the ventilation/perfusion ratio, which was translated to SA using Fick's law of diffusion. The SA was then adjusted using volumetric capnography. RESULTS Thirty infants with a median (range) gestational age of 26.3 (22.9-27.9) weeks were studied. The median (range) adjusted SA was 647.9 (316.4-902.7) cm2. The adjusted SA was lower in the infants who required home oxygen [637.7 (323.5-837.5) cm2] compared to those who did not [799.1 (444.2-902.7) cm2, p = 0.016]. In predicting the need for supplemental home oxygen, the adjusted SA had an area under the receiver operator characteristic curve of 0.815 (p = 0.017). An adjusted SA ≥688.6 cm2 had 86% sensitivity and 77% specificity in predicting the need for supplemental home oxygen. CONCLUSIONS The alveolar surface area can be estimated non-invasively in extremely preterm infants. The adjusted alveolar surface area has the potential to predict the subsequent need for discharge home on supplemental oxygen. IMPACT We describe a novel biomarker of respiratory disease following extremely preterm birth. The adjusted alveolar surface area index was derived by non-invasive measurements of the ventilation/perfusion ratio and adjusted by concurrent measurements of volumetric capnography. The adjusted alveolar surface area was markedly reduced in extremely preterm infants studied at 7 days of life and could predict the need for discharge home on supplemental oxygen. This method could be used at the bedside to estimate the alveolar surface area and provide an index of the severity of lung disease, and assist in monitoring, clinical management and prognosis.
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Affiliation(s)
- Emma E Williams
- Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - J Gareth Jones
- Cambridge University Clinical School, Hills Rd, Cambridge, UK
| | - Donald McCurnin
- Division of Neonatology, Department of Pediatrics, University of Texas Health, San Antonio, TX, USA
| | - Mario Rüdiger
- Neonatology and Pediatric Critical Care Medicine, Department of Pediatrics, Medizinische Fakultät, Carl Gustav Carus, TU Dresden, Dresden, Germany
- Saxony Center for Feto/Neonatal Health, Medizinische Fakultät, TU Dresden, Dresden, Germany
| | - Mahesh Nanjundappa
- Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, London, UK
| | - Anne Greenough
- Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK
- National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK
| | - Theodore Dassios
- Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK.
- Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, London, UK.
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Dassios T, Williams EE, Jones JG, Greenough A. Pathophysiology of gas exchange impairment in extreme prematurity: Insights from combining volumetric capnography and measurements of ventilation/perfusion ratio. Front Pediatr 2023; 11:1094855. [PMID: 37009267 PMCID: PMC10050367 DOI: 10.3389/fped.2023.1094855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 02/28/2023] [Indexed: 04/04/2023] Open
Abstract
Background Infants born extremely preterm often suffer from respiratory disease and are invasively ventilated. We aimed to test the hypothesis that gas exchange in ventilated extremely preterm infants occurs both at the level of the alveoli and via mixing of fresh deadspace gas in the airways. Methods We measured the normalised slopes of phase II and phase III of volumetric capnography and related them with non-invasive measurements of ventilation to perfusion ratio (VA/Q) and right-to-left shunt in ventilated extremely preterm infants studied at one week of life. Cardiac right-to-left shunt was excluded by concurrent echocardiography. Results We studied 25 infants (15 male) with a median (range) gestational age of 26.0 (22.9-27.9) weeks and birth weight of 795 (515-1,165) grams. The median (IQR) VA/Q was 0.52 (0.46-0.56) and shunt was 8 (2-13) %. The median (IQR) normalised slope of phase II was 99.6 (82.7-116.1) mmHg and of phase III was 24.6 (16.9-35.0) mmHg. The VA/Q was significantly related to the normalised slope of phase III (ρ = -0.573, p = 0.016) but not to the slope of phase II (ρ = 0.045, p = 0.770). The right-to-left shunt was not independently associated with either the slope of phase II or the slope of phase III after adjusting for confounding parameters. Conclusions Abnormal gas exchange in ventilated extremely preterm infants was associated with lung disease at the alveolar level. Abnormal gas exchange at the level of the airways was not associated with quantified indices of gas exchange impairment.
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Affiliation(s)
- Theodore Dassios
- Women and Children’s Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
- Neonatal Intensive Care Unit, Patras University Hospital, Patras, Greece
- Correspondence: Theodore Dassios
| | - Emma E. Williams
- Women and Children’s Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
| | - J. Gareth Jones
- Cambridge University Clinical School, Cambridge, United Kingdom
| | - Anne Greenough
- Women and Children’s Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
- National Institute for Health Research (NIHR) Biomedical Research Centre Based at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London, London, United Kingdom
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Salverda HH, Cramer SJE, Witlox RSGM, Dargaville PA, Te Pas AB. Automated oxygen control in preterm infants, how does it work and what to expect: a narrative review. Arch Dis Child Fetal Neonatal Ed 2021; 106:215-221. [PMID: 32732378 DOI: 10.1136/archdischild-2020-318918] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 11/03/2022]
Abstract
BACKGROUND Automated oxygen control systems are finding their way into contemporary ventilators for preterm infants, each with its own algorithm, strategy and effect. OBJECTIVE To provide guidance to clinicians seeking to comprehend automated oxygen control and possibly introduce this technology in their practice. METHOD A narrative review of the commercially available devices using different algorithms incorporating rule-based, proportional-integral-derivative and adaptive concepts are described and explained. An overview of how they work and, if available, the clinical effect is given. RESULTS All algorithms have shown a beneficial effect on the proportion of time that oxygen saturation is within target range, and a decrease in hyperoxia and severe hypoxia. Automated oxygen control may also reduce the workload for bedside staff. There is concern that such devices could mask clinical deterioration, however this has not been reported to date. CONCLUSIONS So far, trials involving different algorithms are heterogenous in design and no head-to-head comparisons have been made, making it difficult to differentiate which algorithm is most effective and what clinicians can expect from algorithms under certain conditions.
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Affiliation(s)
- Hylke H Salverda
- Neonatology, Leiden University Medical Center, Leiden, Zuid-Holland, The Netherlands
| | - Sophie J E Cramer
- Neonatology, Leiden University Medical Center, Leiden, Zuid-Holland, The Netherlands
| | - Ruben S G M Witlox
- Neonatology, Leiden University Medical Center, Leiden, Zuid-Holland, The Netherlands
| | - Peter A Dargaville
- Department of Pediatrics, Royal Hobart Hospital, Hobart, Tasmania, Australia.,Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Arjan B Te Pas
- Neonatology, Leiden University Medical Center, Leiden, Zuid-Holland, The Netherlands
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Stoecklin B, Choi YJ, Rakshasbhuvankar A, Svedenkrans J, Jones G, Pillow J. Simplified bedside assessment of pulmonary gas exchange in very preterm infants at 36 weeks' postmenstrual age. Thorax 2021; 76:689-695. [PMID: 33574124 DOI: 10.1136/thoraxjnl-2020-214659] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 01/01/2021] [Accepted: 01/14/2021] [Indexed: 12/22/2022]
Abstract
INTRODUCTION We aimed to develop and validate a prediction table for a simplified measure of rightward shift of the fetal oxyhaemoglobin saturation (SpO2) versus inspired oxygen pressure (P IO2) curve as an objective marker of lung disease severity in very preterm infants, independent of unit altitude or oxygen prescribing policies. METHODS Very preterm infants (n=219) had an oxygen reduction test at median (IQR) test age of 354 (345-360) weeks' postmenstrual age (PMA). Shift was derived from at least three paired SpO2 versus P IO2 measurements using a computer algorithm, using the fetal oxyhaemoglobin dissociation curve as the reference. Linear regression of resultant shift values enabled construction of a table to predict shift using a single paired SpO2 versus P IO2 measurement, validated subsequently in a separate infant cohort using Bland-Altman analysis. Receiver operating curve analysis provided threshold values equating to a clinical diagnosis of mild bronchopulmonary dysplasia (BPD) or moderate to severe BPD. RESULTS The median (IQR) age of 63 infants in the validation cohort was 360 (356-362) weeks' PMA. Mean difference (95% CI) between predicted and measured shift was 2.1 (-0.8% to 4.9%) with wide limits of agreement (-20.7% to 24.8%). Predicted shift >10.1 kPa identified mild BPD with 71% sensitivity and 88% specificity while values>13.0 kPa identified moderate to severe BPD with 81% sensitivity and 100% specificity. DISCUSSION Shift predicted from a single paired SpO2 versus P IO2 measurement using our validated table enables objective bedside screening of lung disease severity in very preterm infant cohorts at 36 weeks' PMA.
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Affiliation(s)
- Benjamin Stoecklin
- School of Human Sciences, University of Western Australia, Perth, Western Australia, Australia .,Neonatal Clinical Care Unit, King Edward Memorial Hospital for Women, Subiaco, Western Australia, Australia.,Department of Neonatology, University of Basel Children's Hospital, Basel, Switzerland
| | - Y Jane Choi
- School of Human Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - Abhijeet Rakshasbhuvankar
- School of Human Sciences, University of Western Australia, Perth, Western Australia, Australia.,Neonatal Clinical Care Unit, King Edward Memorial Hospital for Women, Subiaco, Western Australia, Australia
| | - Jenny Svedenkrans
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.,Department of Neonatal Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Gareth Jones
- Department of Anaesthesia, Addenbrooke's Hospital, Cambridge, UK
| | - Jane Pillow
- School of Human Sciences, University of Western Australia, Perth, Western Australia, Australia
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Choi YJ, Stoecklin B, Hemy NR, Hall GL, Doherty DA, Simpson SJ, Pillow JJ. Pulmonary Gas Exchange Improves over the First Year in Preterm Infants with and without Bronchopulmonary Dysplasia. Neonatology 2021; 118:98-105. [PMID: 33592606 DOI: 10.1159/000513357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/25/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Right shift of the peripheral oxyhaemoglobin saturation (SpO2) versus inspired oxygen pressure (PIO2) curve is a sensitive marker of pulmonary gas exchange. OBJECTIVES The aim of this study was to assess the impact of prematurity and bronchopulmonary dysplasia (BPD) on gas exchange and right-to-left shunt in the neonatal period, and its evolution over the first year of life. METHOD We assessed shift and shunt in extremely preterm (EP) and very preterm (VP) infants at 36 and 44 weeks' postmenstrual age (PMA), and at 1-year corrected postnatal age (cPNA). PIO2 was decreased stepwise to achieve SpO2 between 85 and 98%. Shift and shunt were calculated from paired SpO2/PIO2 measurements using customized software. Results were examined cross-sectionally at each time point, and longitudinally using generalized linear regression. Term infants were assessed at 44 wk PMA as a comparative reference. RESULTS Longitudinal modelling showed continuous decline in shift in EP and VP infants during the first year of life. There was no difference in shift compared to term infants at 44 wk PMA (p = 0.094). EP infants with BPD had higher shift than infants without BPD at 36 wk PMA (p < 0.001) and 44 wk PMA (p = 0.005) but not at 1-year cPNA. CONCLUSIONS In the absence of lung disease, prematurity per se did not result in reduced gas exchange at 1-year cPNA. We report ongoing, significant improvements in pulmonary gas exchange in all preterm infants during the first year of life, despite evidence of early deficits in gas exchange in EP infants with BPD.
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Affiliation(s)
- Y Jane Choi
- Telethon Kids Institute, Perth, Washington, Australia.,School of Human Sciences, University of Western Australia, Perth, Washington, Australia
| | - Benjamin Stoecklin
- School of Human Sciences, University of Western Australia, Perth, Washington, Australia.,Department of Neonatology, University Children's Hospital Basel, Basel, Switzerland
| | - Naomi R Hemy
- Telethon Kids Institute, Perth, Washington, Australia
| | - Graham L Hall
- Telethon Kids Institute, Perth, Washington, Australia.,School of Physiotherapy and Exercise Science, Curtin University, Perth, Washington, Australia
| | - Dorota A Doherty
- Division of Obstetrics and Gynaecology, Medical School, University of Western Australia, Perth, Washington, Australia
| | - Shannon J Simpson
- Telethon Kids Institute, Perth, Washington, Australia.,School of Physiotherapy and Exercise Science, Curtin University, Perth, Washington, Australia
| | - J Jane Pillow
- Telethon Kids Institute, Perth, Washington, Australia, .,School of Human Sciences, University of Western Australia, Perth, Washington, Australia,
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Svedenkrans J, Stoecklin B, Jones JG, Doherty DA, Pillow JJ. Physiology and Predictors of Impaired Gas Exchange in Infants with Bronchopulmonary Dysplasia. Am J Respir Crit Care Med 2020; 200:471-480. [PMID: 30789787 DOI: 10.1164/rccm.201810-2037oc] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Rationale: A sensitive outcome measure for infants with bronchopulmonary dysplasia would facilitate clinical benchmarking and enhance epidemiologic understanding, evaluation of clinical interventions, and outcome prediction.Objectives: Noninvasive assessment of pulmonary gas exchange in preterm infants with and without bronchopulmonary dysplasia to grade disease severity and to identify determinants of impaired gas exchange.Methods: This is a prospective observational study in very preterm infants. Inspired oxygen partial pressure (PiO2) was decreased stepwise to achieve oxygen saturation as measured by pulse oximetry (SpO2) that decreased from 95% to 86%. Right shift, V⋅a/Q⋅, and right-left shunt were derived from the resulting SpO2 versus PiO2 curve and compared with current disease severity classification. Potential determinants of shift, V⋅a/Q⋅, and shunt were identified using principal components analysis and multiple linear regression.Measurements and Main Results: A total of 219 infants with median (interquartile range) gestation of 28 weeks and 0 days (26 weeks and 0 days to 29 weeks and 0 days) had a valid study at 35 weeks and 4 days (34 weeks and 1 day to 39 weeks and 3 days) of postmenstrual age. Shift increased and V⋅a/Q⋅ decreased as severity of bronchopulmonary dysplasia increased. Infants with moderate-severe disease also had increased shunt. Extent of impaired gas exchange overlapped between severity groups. Infants requiring mechanical support but no supplemental oxygen at 36 weeks' postmenstrual age had similar values of shift, V⋅a/Q⋅, and shunt to preterm infants without bronchopulmonary dysplasia. Lower gestation and increased duration of invasive ventilation independently predicted increased shift, decreased V⋅a/Q⋅, and increased shunt. Shift was the most sensitive and specific index of the severity of bronchopulmonary dysplasia.Conclusions: Most infants with bronchopulmonary dysplasia have impaired oxygenation quantified by a simple, sensitive bedside test. Shift of the SpO2/PiO2 curve may be useful for prediction and measurement of preterm infant respiratory outcomes.
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Affiliation(s)
- Jenny Svedenkrans
- 1Centre for Neonatal Research and Education.,2Division of Pediatrics, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden.,3Department of Neonatal Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Benjamin Stoecklin
- 1Centre for Neonatal Research and Education.,4School of Human Sciences, and.,5Neonatal Clinical Care Unit, King Edward Memorial Hospital, Perth, Australia; and
| | - J Gareth Jones
- 6University Department of Anaesthesia, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Dorota A Doherty
- 7Division of Obstetrics and Gynaecology, Medical School, University of Western Australia, Perth, Australia
| | - J Jane Pillow
- 1Centre for Neonatal Research and Education.,4School of Human Sciences, and
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Abstract
Infants in the Neonatal Oxygenation Prospective Meta-analysis trials were randomized to SpO2 targets of 85% to 89% or 91% to 95%. Group allocation was masked. Different outcomes are likely partially attributable to differences in achieved SpO2. Infants randomized to the lower range had higher than intended readings. SpO2 distributions of infants in the low-range group of the Benefits of Oxygen Saturation Targeting II UK trial who died or developed necrotizing enterocolitis were centered around 90% to 92%. These achieved SpO2 distributions caution against using lower SpO2 target ranges early or throughout the clinical course in extremely preterm infants.
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Affiliation(s)
- Benjamin J Stenson
- Neonatal Unit, Royal Infirmary of Edinburgh, 46 Little France Crescent, Edinburgh EH16 4SA, UK.
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Bachman TE, Newth CJL, Iyer NP, Ross PA, Khemani RG. Hypoxemic and hyperoxemic likelihood in pulse oximetry ranges: NICU observational study. Arch Dis Child Fetal Neonatal Ed 2019; 104:F274-F279. [PMID: 29925540 DOI: 10.1136/archdischild-2017-314448] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 05/29/2018] [Accepted: 05/30/2018] [Indexed: 01/14/2023]
Abstract
OBJECTIVE Describe the likelihood of hypoxemia and hyperoxemia across ranges of oxygen saturation (SpO2), during mechanical ventilation with supplemental oxygenation. DESIGN Retrospective observational study. SETTING University affiliated tertiary care neonatal intensive care unit. PATIENTS Two groups of neonates based on postmenstrual age (PMA): <32 weeks (n=104) and >36 weeks (n=709). MAIN MEASURES Hypoxemia was defined as a PaO2 <40 mm Hg, hyperoxemia as a PaO2 of >99 mm Hg and normoxemia as a PaO2 of 50-80 mm Hg. Twenty-five per cent was defined as marked likelihood of hypoxemia or hyperoxemia. RESULTS From these infants, 18 034 SpO2-PaO2 pairs were evaluated of which 10% were preterm. The PMA (median and IQR) of the two groups were: 28 weeks (27-30) and 40 weeks (38-41). With SpO2 levels between 90% and 95%, the likelihoods of hypoxemia and hyperoxemia were low and balanced. With increasing levels of SpO2, the likelihood of hyperoxemia increased. It became marked in the preterm group when SpO2 was 99%-100% (95% CI 29% to 41%) and in the term group with SpO2 levels of 96%-98% (95% CI 29% to 32%). The likelihood of hypoxemia increased as SpO2 decreased. It became marked in both with SpO2 levels of 80%-85% (95% CI 20% to 31%, 24% to 28%, respectively). CONCLUSIONS The likelihood of a PaO2 <40 mm Hg is marked with SpO2 below 86%. The likelihood of a PaO2 >99 mm Hg is marked in term infants with SpO2 above 95% and above 98% in preterm infants. SpO2 levels between 90% and 95% are appropriate targets for term and preterm infants.
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Affiliation(s)
- Thomas E Bachman
- Biomedical Technology, Faculty of Biomedical Engineering, Czech Technical University in Prague, Kladno, Czech Republic
| | - Christopher J L Newth
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, California, USA
| | - Narayan P Iyer
- Neonatology, Fetal and Neonatal Institute, Children's Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, California, USA
| | - Patrick A Ross
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, California, USA
| | - Robinder G Khemani
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, University of Southern California Keck School of Medicine, Los Angeles, California, USA
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Oxygen Treatment for Immature Infants beyond the Delivery Room: Lessons from Randomized Studies. J Pediatr 2018; 200:12-18. [PMID: 29961642 DOI: 10.1016/j.jpeds.2018.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 04/30/2018] [Accepted: 05/01/2018] [Indexed: 12/11/2022]
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van Zanten HA, Pauws SC, Stenson BJ, Walther FJ, Lopriore E, Te Pas AB. Effect of a smaller target range on the compliance in targeting and distribution of oxygen saturation in preterm infants. Arch Dis Child Fetal Neonatal Ed 2018; 103:F430-F435. [PMID: 28970321 DOI: 10.1136/archdischild-2016-312496] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 08/08/2017] [Accepted: 09/07/2017] [Indexed: 11/04/2022]
Abstract
BACKGROUND Following recent recommendations, the oxygen saturation (SpO2) target range for preterm infants in our nursery was narrowed towards the higher end from 85%-95% to 90%-95%. We determined the effect of narrowing the SpO2 target range on the compliance in target range and distribution of SpO2 in preterm infants. METHODS Before and after changing the target range from 85%-95% to 90%-95%, infants <30 weeks of gestation receiving oxygen were compared during their admission on the neonatal intensive care unit. For each infant, distribution of SpO2 was noted by collecting SpO2 samples each minute, and the percentage of time spent with SpO2 within 90%-95% was calculated. Oxygen was manually adjusted. Hypoxaemic events (SpO2 <80%) where oxygen was titrated were analysed. RESULTS Data were analysed for 104 infants (57 before and 47 after the range was narrowed). The narrower range was associated with an increase in the median (IQR) SpO2 (93% (91%-96%) vs 94% (92%-97%), p=0.01), but no increase in median time SpO2 within 90%-95% (49.2% (39.6%-59.7%) vs (46.9% (27.1%-57.9%), p=0.72). The distribution of SpO2 shifted to the right with a significant decrease in SpO2 <90%, but not <80%. The count of minute values for Sp02 <80% decreased, while the frequency and duration of hypoxaemic events and oxygen titration were not different. CONCLUSION Narrowing the target range from 85%-95% to 90%-95% in preterm infants was associated with an increase in median SpO2 and a rightward shift in the distribution, but no change in time spent between 90% and 95%.
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Affiliation(s)
- Henriëtte Anje van Zanten
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, Zuid-Holland, The Netherlands
| | - Steffen C Pauws
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, Zuid-Holland, The Netherlands.,TiCC, Tilburg University, Tilburg, Noord-Brabant, The Netherlands
| | - Ben J Stenson
- Neonatal Unit, Simpson Centre for Reproductive Health, Edinburgh Royal Infirmary, Edinburgh, UK
| | - Frans J Walther
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, Zuid-Holland, The Netherlands
| | - Enrico Lopriore
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, Zuid-Holland, The Netherlands
| | - Arjan B Te Pas
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, Zuid-Holland, The Netherlands
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Dargaville PA, Sadeghi Fathabadi O, Plottier GK, Lim K, Wheeler KI, Jayakar R, Gale TJ. Development and preclinical testing of an adaptive algorithm for automated control of inspired oxygen in the preterm infant. Arch Dis Child Fetal Neonatal Ed 2017; 102:F31-F36. [PMID: 27634820 DOI: 10.1136/archdischild-2016-310650] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 08/21/2016] [Accepted: 08/22/2016] [Indexed: 01/17/2023]
Abstract
OBJECTIVE To assess the performance of a novel algorithm for automated oxygen control using a simulation of oxygenation founded on in vivo data from preterm infants. METHODS A proportional-integral-derivative (PID) control algorithm was enhanced by (i) compensation for the non-linear SpO2-PaO2 relationship, (ii) adaptation to the severity of lung dysfunction and (iii) error attenuation within the target range. Algorithm function with and without enhancements was evaluated by iterative linking with a computerised simulation of oxygenation. Data for this simulation (FiO2 and SpO2 at 1 Hz) were sourced from extant recordings from preterm infants (n=16), and converted to a datastream of values for ventilation:perfusion ratio and shunt. Combination of this datastream second by second with the FiO2 values from the algorithm under test produced a sequence of novel SpO2 values, allowing time in the SpO2 target range (91%-95%) and in various degrees of hypoxaemia and hyperoxaemia to be determined. A PID algorithm with 30 s lockout after each FiO2 adjustment, and a proportional-derivative (PD) algorithm were also evaluated. RESULTS Separate addition of each enhancing feature to the PID algorithm showed a benefit, but not with uniformly positive effects. The fully enhanced algorithm was optimal for the combination of targeting the desired SpO2 range and avoiding time in, and episodes of, hypoxaemia and hyperoxaemia. This algorithm performed better than one with a 30 s lockout, and considerably better than PD control. CONCLUSIONS An enhanced PID algorithm was very effective for automated oxygen control in a simulation of oxygenation, and deserves clinical evaluation.
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Affiliation(s)
- Peter A Dargaville
- Neonatal Respiratory Group, Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia.,Department of Paediatrics, Royal Hobart Hospital, Hobart, Tasmania, Australia
| | | | - Gemma K Plottier
- Department of Paediatrics, Royal Hobart Hospital, Hobart, Tasmania, Australia.,School of Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | - Kathleen Lim
- Department of Paediatrics, Royal Hobart Hospital, Hobart, Tasmania, Australia
| | - Kevin I Wheeler
- Neonatal Unit, Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Rohan Jayakar
- School of Engineering and ICT, University of Tasmania, Hobart, Tasmania, Australia
| | - Timothy J Gale
- School of Engineering and ICT, University of Tasmania, Hobart, Tasmania, Australia
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Improving manual oxygen titration in preterm infants by training and guideline implementation. Eur J Pediatr 2017; 176:99-107. [PMID: 27888413 PMCID: PMC5219007 DOI: 10.1007/s00431-016-2811-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/10/2016] [Accepted: 11/14/2016] [Indexed: 11/05/2022]
Abstract
UNLABELLED To study oxygen saturation (SpO2) targeting before and after training and guideline implementation of manual oxygen titration, two cohorts of preterm infants <30 weeks of gestation needing respiratory support and oxygen therapy were compared. The percentage of the time spent with SpO2 within the target range (85-95%) was calculated (%SpO2-wtr). SpO2 was collected every minute when oxygen is >21%. ABCs where oxygen therapy was given were identified and analyzed. After training and guideline implementation the %SpO2-wtr increased (median interquartile range (IQR)) 48.0 (19.6-63.9) % vs 61.9 (48.5-72.3) %; p < 0.005, with a decrease in the %SpO2 > 95% (44.0 (27.8-66.2) % vs 30.8 (22.6-44.5) %; p < 0.05). There was no effect on the %SpO2 < 85% (5.9 (2.8-7.9) % vs 6.2 (2.5-8) %; ns) and %SpO2 < 80% (1.9 (1.0-3.0) % vs 1.7 (0.8-2.6) %; ns). In total, 186 ABCs with oxygen therapy before and 168 ABCs after training and guideline implementation occurred. The duration of SpO2 < 80% reduced (2 (1-2) vs 1 (1-2) minutes; p < 0.05), the occurrence of SpO2 > 95% did not decrease (73% vs 64%; ns) but lasted shorter (2 (0-7) vs 1 (1-3) minute; p < 0.004). CONCLUSION Training and guideline implementation in manual oxygen titration improved SpO2 targeting in preterm infants with more time spent within the target range and less frequent hyperoxaemia. The durations of hypoxaemia and hyperoxaemia during ABCs were shorter. What is Known: • Oxygen saturation targeting in preterm infants can be challenging and the compliance is low when oxygen is titrated manually. • Hyperoxaemia often occurs after oxygen therapy for oxygen desaturation during apnoeas. What is New: • Training and implementing guidelines improved oxygen saturation targeting and reduced hyperoxaemia. • Training and implementing guidelines improved manual oxygen titration during ABC.
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14
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Dassios T, Ali K, Rossor T, Greenough A. Ventilation/perfusion ratio and right to left shunt in healthy newborn infants. J Clin Monit Comput 2016; 31:1229-1234. [PMID: 28012013 DOI: 10.1007/s10877-016-9969-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 12/14/2016] [Indexed: 10/20/2022]
Abstract
Oxygenation impairment can be assessed non-invasively by determining the degree of right-to-left shunt and ventilation/perfusion (VA/Q) inequality. These indices have been used in sick newborn infants, but normative values have not been reported which are essential to determine the magnitude of the abnormality. We, therefore, aimed to measure the shunt and VA/Q in infants with no history of respiratory conditions and determine if there was any effect of supine or prone position and the reproducibility of the data. Data were analysed from infants who had undergone a hypoxic challenge and in a subset who had been assessed in the supine or prone position. Transcutaneous oxygen saturations (SpO2) were recorded at fractions of inspired oxygen (FIO2) of 0.21 and 0.15. Two independent raters used a computer software algorithm which analysed and fitted paired data for FIO2 and SpO2 and derived a curve which represented the best fit for each infant's data and calculated the shunt and VA/Q. The raters ability to interpret the SpO2 value which corresponded to a given FIO2 was compared. The downwards displacement of the FIO2 versus SpO2 curve was used to estimate the degree of right-to-left shunt and the rightwards shift of the curve was used to calculate the VA/Q ratio. The mean (SD) gestational age of the 145 infants was 39 (1.6) weeks, their birth weight was 2990 (578) gms and median (range) postnatal age at measurement 3 (1-8) days. The mean (SD) VA/Q ratio was 0.95 (0.21). None of the infants had a right-to-left shunt. No significant differences were found in VA/Q in the supine compared to the prone position. The intraclass correlation coefficient of VA/Q between two independent raters was 0.968 (95% CI 0.947-0.980), p < 0.001. Right-to-left shunt and VA/Q ratio in healthy newborn infants were similar in the prone compared to the supine position.
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Affiliation(s)
- Theodore Dassios
- Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, 4th Floor Golden Jubilee Wing, Denmark Hill, SE5 9RS, London, UK.
| | - Kamal Ali
- Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, 4th Floor Golden Jubilee Wing, Denmark Hill, SE5 9RS, London, UK
| | - Thomas Rossor
- Division of Asthma, Allergy and Lung Biology, MRC-Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, UK
| | - Anne Greenough
- Division of Asthma, Allergy and Lung Biology, MRC-Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, UK.,National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, UK
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