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Raimondi Cominesi D, Forcione M, Pozzi M, Giani M, Foti G, Rezoagli E, Cipulli F. Pulmonary shunt in critical care: a practical approach with clinical scenarios. JOURNAL OF ANESTHESIA, ANALGESIA AND CRITICAL CARE 2024; 4:18. [PMID: 38449055 PMCID: PMC10916277 DOI: 10.1186/s44158-024-00147-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Accepted: 01/30/2024] [Indexed: 03/08/2024]
Abstract
BACKGROUND Pulmonary shunt refers to the passage of venous blood into the arterial blood system bypassing the alveoli-blood gas exchange. Pulmonary shunt is defined by a drop in the physiologic coupling of lung ventilation and lung perfusion. This may consequently lead to respiratory failure. MAIN BODY The pulmonary shunt assessment is often neglected. From a mathematical point of view, pulmonary shunt can be assessed by estimating the degree of mixing between oxygenated and deoxygenated blood. To compute the shunt, three key components are analyzed: the oxygen (O2) content in the central venous blood before gas exchange, the calculated O2 content in the pulmonary capillaries after gas exchange, and the O2 content in the arterial system, after the mixing of shunted and non-shunted blood. Computing the pulmonary shunt becomes of further importance in patients on extracorporeal membrane oxygenation (ECMO), as arterial oxygen levels may not directly reflect the gas exchange of the native lung. CONCLUSION In this review, the shunt analysis and its practical clinical applications in different scenarios are discussed by using an online shunt simulator.
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Affiliation(s)
| | - Mario Forcione
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Matteo Pozzi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Department of Emergency and Intensive Care, Fondazione IRCCS San Gerardo Dei Tintori, Monza, Italy
| | - Marco Giani
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Department of Emergency and Intensive Care, Fondazione IRCCS San Gerardo Dei Tintori, Monza, Italy
| | - Giuseppe Foti
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Department of Emergency and Intensive Care, Fondazione IRCCS San Gerardo Dei Tintori, Monza, Italy
| | - Emanuele Rezoagli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
- Department of Emergency and Intensive Care, Fondazione IRCCS San Gerardo Dei Tintori, Monza, Italy.
| | - Francesco Cipulli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
- Department of Emergency and Intensive Care, Fondazione IRCCS San Gerardo Dei Tintori, Monza, Italy
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2
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Omar M, Omote K, Sorimachi H, Popovic D, Kanwar A, Alogna A, Reddy YNV, Lim KG, Shah SJ, Borlaug BA. Hypoxaemia in patients with heart failure and preserved ejection fraction. Eur J Heart Fail 2023; 25:1593-1603. [PMID: 37317621 DOI: 10.1002/ejhf.2930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/16/2023] Open
Abstract
AIMS It is widely held that heart failure (HF) does not cause exertional hypoxaemia, based upon studies in HF with reduced ejection fraction, but this may not apply to patients with HF and preserved ejection fraction (HFpEF). Here, we characterize the prevalence, pathophysiology, and clinical implications of exertional arterial hypoxaemia in HFpEF. METHODS AND RESULTS Patients with HFpEF (n = 539) and no coexisting lung disease underwent invasive cardiopulmonary exercise testing with simultaneous blood and expired gas analysis. Exertional hypoxaemia (oxyhaemoglobin saturation <94%) was observed in 136 patients (25%). As compared to those without hypoxaemia (n = 403), patients with hypoxaemia were older and more obese. Patients with HFpEF and hypoxaemia had higher cardiac filling pressures, higher pulmonary vascular pressures, greater alveolar-arterial oxygen difference, increased dead space fraction, and greater physiologic shunt compared to those without hypoxaemia. These differences were replicated in a sensitivity analysis where patients with spirometric abnormalities were excluded. Regression analyses revealed that increases in pulmonary arterial and pulmonary capillary pressures were related to lower arterial oxygen tension (PaO2 ), especially during exercise. Body mass index (BMI) was not correlated with the arterial PaO2 , and hypoxaemia was associated with increased risk for death over 2.8 (interquartile range 0.7-5.5) years of follow-up, even after adjusting for age, sex, and BMI (hazard ratio 2.00, 95% confidence interval 1.01-3.96; p = 0.046). CONCLUSION Between 10% and 25% of patients with HFpEF display arterial desaturation during exercise that is not ascribable to lung disease. Exertional hypoxaemia is associated with more severe haemodynamic abnormalities and increased mortality. Further study is required to better understand the mechanisms and treatment of gas exchange abnormalities in HFpEF.
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Affiliation(s)
- Massar Omar
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- Department of Cardiology, Odense University Hospital, Odense, Denmark
- Steno Diabetes Center Odense, Odense University Hospital, Odense, Denmark
| | - Kazunori Omote
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Hidemi Sorimachi
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Dejana Popovic
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | | | - Alessio Alogna
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Yogesh N V Reddy
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Kaiser G Lim
- Department of Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, MN, USA
| | - Sanjiv J Shah
- Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Barry A Borlaug
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
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3
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Sarkar M, Madabhavi I, Kadakol N. Oxygen-induced hypercapnia: physiological mechanisms and clinical implications. Monaldi Arch Chest Dis 2022. [DOI: 10.4081/monaldi.2022.2399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 10/24/2022] [Indexed: 11/19/2022] Open
Abstract
Oxygen is probably the most commonly prescribed drug in the emergency setting and is a life-saving modality as well. However, like any other drug, oxygen therapy may also lead to various adverse effects. Patients with chronic obstructive pulmonary disease (COPD) may develop hypercapnia during supplemental oxygen therapy, particularly if uncontrolled. The risk of hypercapnia is not restricted to COPD only; it has also been reported in patients with morbid obesity, asthma, cystic fibrosis, chest wall skeletal deformities, bronchiectasis, chest wall deformities, or neuromuscular disorders. However, the risk of hypercapnia should not be a deterrent to oxygen therapy in hypoxemic patients with chronic lung diseases, as hypoxemia may lead to life-threatening cardiovascular complications. Various mechanisms leading to the development of oxygen-induced hypercapnia are the abolition of ‘hypoxic drive’, loss of hypoxic vasoconstriction and absorption atelectasis leading to an increase in dead-space ventilation and Haldane effect. The international guideline recommends a target oxygen saturation of 88% to 92% in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and other chronic lung diseases at risk of hypercapnia. Oxygen should be administered only when oxygen saturation is below 88%. We searched PubMed, EMBASE, and the CINAHL from inception to June 2022. We used the following search terms: “Hypercapnia”, “Oxygen therapy in COPD”, “Oxygen-associated hypercapnia”, “oxygen therapy”, and “Hypoxic drive”. All types of study are selected. This review will focus on the physiological mechanisms of oxygen-induced hypercapnia and its clinical implications.
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Rezoagli E, Laffey JG, Bellani G. Monitoring Lung Injury Severity and Ventilation Intensity during Mechanical Ventilation. Semin Respir Crit Care Med 2022; 43:346-368. [PMID: 35896391 DOI: 10.1055/s-0042-1748917] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Acute respiratory distress syndrome (ARDS) is a severe form of respiratory failure burden by high hospital mortality. No specific pharmacologic treatment is currently available and its ventilatory management is a key strategy to allow reparative and regenerative lung tissue processes. Unfortunately, a poor management of mechanical ventilation can induce ventilation induced lung injury (VILI) caused by physical and biological forces which are at play. Different parameters have been described over the years to assess lung injury severity and facilitate optimization of mechanical ventilation. Indices of lung injury severity include variables related to gas exchange abnormalities, ventilatory setting and respiratory mechanics, ventilation intensity, and the presence of lung hyperinflation versus derecruitment. Recently, specific indexes have been proposed to quantify the stress and the strain released over time using more comprehensive algorithms of calculation such as the mechanical power, and the interaction between driving pressure (DP) and respiratory rate (RR) in the novel DP multiplied by four plus RR [(4 × DP) + RR] index. These new parameters introduce the concept of ventilation intensity as contributing factor of VILI. Ventilation intensity should be taken into account to optimize protective mechanical ventilation strategies, with the aim to reduce intensity to the lowest level required to maintain gas exchange to reduce the potential for VILI. This is further gaining relevance in the current era of phenotyping and enrichment strategies in ARDS.
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Affiliation(s)
- Emanuele Rezoagli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Department of Emergency and Intensive Care, San Gerardo University Hospital, Monza, Italy
| | - John G Laffey
- School of Medicine, National University of Ireland, Galway, Ireland.,Department of Anaesthesia and Intensive Care Medicine, Galway University Hospitals, Saolta University Hospital Group, Galway, Ireland.,Lung Biology Group, Regenerative Medicine Institute (REMEDI) at CÚRAM Centre for Research in Medical Devices, National University of Ireland Galway, Galway, Ireland
| | - Giacomo Bellani
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Department of Emergency and Intensive Care, San Gerardo University Hospital, Monza, Italy
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5
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Mistry S, Das A, Saffaran S, Yehya N, Scott TE, Chikhani M, Laffey JG, Hardman JG, Camporota L, Bates DG. Validation of at-the-bedside formulae for estimating ventilator driving pressure during airway pressure release ventilation using computer simulation. Respir Res 2022; 23:101. [PMID: 35473715 PMCID: PMC9039982 DOI: 10.1186/s12931-022-01985-z] [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: 12/22/2021] [Accepted: 03/07/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Airway pressure release ventilation (APRV) is widely available on mechanical ventilators and has been proposed as an early intervention to prevent lung injury or as a rescue therapy in the management of refractory hypoxemia. Driving pressure ([Formula: see text]) has been identified in numerous studies as a key indicator of ventilator-induced-lung-injury that needs to be carefully controlled. [Formula: see text] delivered by the ventilator in APRV is not directly measurable in dynamic conditions, and there is no "gold standard" method for its estimation. METHODS We used a computational simulator matched to data from 90 patients with acute respiratory distress syndrome (ARDS) to evaluate the accuracy of three "at-the-bedside" methods for estimating ventilator [Formula: see text] during APRV. RESULTS Levels of [Formula: see text] delivered by the ventilator in APRV were generally within safe limits, but in some cases exceeded levels specified by protective ventilation strategies. A formula based on estimating the intrinsic positive end expiratory pressure present at the end of the APRV release provided the most accurate estimates of [Formula: see text]. A second formula based on assuming that expiratory flow, volume and pressure decay mono-exponentially, and a third method that requires temporarily switching to volume-controlled ventilation, also provided accurate estimates of true [Formula: see text]. CONCLUSIONS Levels of [Formula: see text] delivered by the ventilator during APRV can potentially exceed levels specified by standard protective ventilation strategies, highlighting the need for careful monitoring. Our results show that [Formula: see text] delivered by the ventilator during APRV can be accurately estimated at the bedside using simple formulae that are based on readily available measurements.
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Affiliation(s)
- Sonal Mistry
- School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | - Anup Das
- School of Engineering, University of Warwick, Coventry, CV4 7AL, UK
| | - Sina Saffaran
- Faculty of Engineering Science, University College London, London, WC1E 6BT, UK
| | - Nadir Yehya
- Department of Anaesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA
| | - Timothy E Scott
- Academic Department of Military Anaesthesia and Critical Care, Royal Centre for Defence Medicine, ICT Centre, Birmingham, B15 2SQ, UK
| | - Marc Chikhani
- Nottingham University Hospitals NHS Trust, Nottingham, NG7 2UH, UK
| | - John G Laffey
- Anaesthesia and Intensive Care Medicine, School of Medicine, NUI Galway, Galway, Ireland
| | - Jonathan G Hardman
- Nottingham University Hospitals NHS Trust, Nottingham, NG7 2UH, UK.,Anaesthesia & Critical Care, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Luigi Camporota
- Department of Critical Care, Guy's and St Thomas' NHS Foundation Trust, London, UK.
| | - Declan G Bates
- School of Engineering, University of Warwick, Coventry, CV4 7AL, UK.
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6
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Ewert R, Stubbe B, Heine A, Desole S, Habedank D, Knaack C, Hortien F, Opitz CF. [Invasive Cardiopulmonary Exercise Testing: A Review]. Pneumologie 2021; 76:98-111. [PMID: 34844269 DOI: 10.1055/a-1651-7450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Right heart catheterization (RHC) is the internationally standardized reference method for measuring pulmonary hemodynamics under resting conditions. In recent years, increasing efforts have been made to establish the reliable assessment of exercise hemodynamics as well, in order to obtain additional diagnostic and prognostic data. Furthermore, cardiopulmonary exercise testing (CPET), as the most comprehensive non-invasive exercise test, is increasingly performed in combination with RHC providing detailed pathophysiological insights into the exercise response, so-called invasive cardiopulmonary exercise testing (iCPET).In this review, the accumulated experience with iCPET is presented and methodological details are discussed. This complex examination is especially helpful in differentiating the underlying causes of unexplained dyspnea. In particular, early forms of cardiac or pulmonary vascular dysfunction can be detected by integrated analysis of hemodynamic as well as ventilatory and gas exchange data. It is expected that with increasing validation of iCPET parameters, a more reliable differentiation of normal from pathological stress reactions will be possible.
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Affiliation(s)
- Ralf Ewert
- Universitätsmedizin Greifswald, Klinik für Innere Medizin B, Bereich Pneumologie und Weaningzentrum, Greifswald
| | - Beate Stubbe
- Universitätsmedizin Greifswald, Klinik für Innere Medizin B, Bereich Pneumologie und Weaningzentrum, Greifswald
| | - Alexander Heine
- Universitätsmedizin Greifswald, Klinik für Innere Medizin B, Bereich Pneumologie und Weaningzentrum, Greifswald
| | - Susanna Desole
- Universitätsmedizin Greifswald, Klinik für Innere Medizin B, Bereich Pneumologie und Weaningzentrum, Greifswald
| | - Dirk Habedank
- DRK Kliniken Berlin Köpenick, Medizinische Klinik Kardiologie, Berlin
| | - Christine Knaack
- Universitätsmedizin Greifswald, Klinik für Innere Medizin C, Greifswald
| | - Franziska Hortien
- Universitätsmedizin Greifswald, Klinik für Innere Medizin B, Bereich Pneumologie und Weaningzentrum, Greifswald
| | - Christian F Opitz
- DRK Kliniken Berlin Westend, Klinik für Innere Medizin, Schwerpunkt Kardiologie, Berlin
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7
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Kara M, Bilen MM, Tekgündüz KŞ, Laloğlu F, Ceviz N. Relation of shunt index with the patent ductus arteriosus among preterm infants under 30 weeks or 1500 g. J Matern Fetal Neonatal Med 2020; 33:4016-4021. [PMID: 30909769 DOI: 10.1080/14767058.2019.1594191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Objective: Patent ductus arteriosus is an important problem in preterms. We aimed to investigate the relation of patent ductus arteriosus with shunt index.Methods: The preterm infants with a birth weight of ≤1500 g and/or gestational age of <30 weeks and an indication for umbilical artery and venous catheterization formed the study group. Between the postnatal 24-48 hours, the first arterial and venous blood samples were obtained and the patients were evaluated by echocardiography. In patients with hemodynamically significant patent ductus arteriosus (patient group), during the first 24 hours after the competition of the first course of medical treatment, the second blood samples were obtained and echocardiography repeated. In patients without patent ductus arteriosus (control group), second blood samples were taken after the postnatal 72 hours. Also, echocardiography was performed.Results: A total of 60 infants, (female = 29, male = 31), were included in the study. We did not find a statistically significant relation between shunt index and the presence of patent ductus arteriosus (p > .05). A statistically significant positive correlation between the fraction of inspired oxygen and shunt index was found. As the postnatal ages progressed, the shunt index values tended to decrease significantly.Conclusion: Our results suggest that shunt index cannot be used as an indicator of hemodynamically significant patent ductus arteriosus in preterm infants. The postnatal age and fraction of inspired oxygen have a significant effect on shunt index in these patients. It was thought that the other possible factors that affect the shunt index should be investigated in preterms between certain postnatal ages.
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Affiliation(s)
- Mustafa Kara
- Department of Pediatrics, Division of Neonatology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Mustafa M Bilen
- Department of Pediatrics, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Kadir Ş Tekgündüz
- Department of Pediatrics, Division of Neonatology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Fuat Laloğlu
- Department of Pediatrics, Division of Pediatric Cardiology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
| | - Naci Ceviz
- Department of Pediatrics, Division of Pediatric Cardiology, Faculty of Medicine, Atatürk University, Erzurum, Turkey
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8
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Uquillas E, Dart CM, Perkins NR, Dart AJ. Effect of reducing inspired oxygen concentration on oxygenation parameters during general anaesthesia in horses in lateral or dorsal recumbency. Aust Vet J 2017; 96:46-53. [PMID: 29265178 DOI: 10.1111/avj.12662] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 05/26/2017] [Accepted: 06/22/2017] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To compare the effects of two concentrations of oxygen delivered to the anaesthetic breathing circuit on oxygenation in mechanically ventilated horses anaesthetised with isoflurane and positioned in dorsal or lateral recumbency. METHODS Selected respiratory parameters and blood lactate were measured and oxygenation indices calculated, before and during general anaesthesia, in 24 laterally or dorsally recumbent horses. Horses were randomly assigned to receive 100% or 60% oxygen during anaesthesia. All horses were anaesthetised using the same protocol and intermittent positive pressure ventilation (IPPV) was commenced immediately following anaesthetic induction and endotracheal intubation. Arterial blood gas analysis was performed and oxygenation indices calculated before premedication, immediately after induction, at 10 and 45 min after the commencement of mechanical ventilation, and in recovery. RESULTS During anaesthesia, the arterial partial pressure of oxygen was adequate in all horses, regardless of position of recumbency or the concentration of oxygen provided. At 10 and 45 min after commencing IPPV, the arterial partial pressure of oxygen was lower in horses in dorsal recumbency compared with those in lateral recumbency, irrespective of the concentration of oxygen supplied. Based on oxygenation indices, pulmonary function during general anaesthesia in horses placed in dorsal recumbency was more compromised than in horses in lateral recumbency, irrespective of the concentration of oxygen provided. CONCLUSION During general anaesthesia, using oxygen at a concentration of 60% instead of 100% maintains adequate arterial oxygenation in horses in dorsal or lateral recumbency. However, it will not reduce pulmonary function abnormalities induced by anaesthesia and recumbency.
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Affiliation(s)
- E Uquillas
- Research and Clinical Trials Unit, University Veterinary Teaching Hospital Camden, School of Veterinary Science, University of Sydney, 410 Werombi Road, Camden, New South Wales, 2570, Australia
| | - C M Dart
- Research and Clinical Trials Unit, University Veterinary Teaching Hospital Camden, School of Veterinary Science, University of Sydney, 410 Werombi Road, Camden, New South Wales, 2570, Australia
| | - N R Perkins
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - A J Dart
- Research and Clinical Trials Unit, University Veterinary Teaching Hospital Camden, School of Veterinary Science, University of Sydney, 410 Werombi Road, Camden, New South Wales, 2570, Australia
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9
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Pilcher J, Richards M, Eastlake L, McKinstry SJ, Bardsley G, Jefferies S, Braithwaite I, Weatherall M, Beasley R. High flow or titrated oxygen for obese medical inpatients: a randomised crossover trial. Med J Aust 2017; 207:430-434. [PMID: 29129174 DOI: 10.5694/mja17.00270] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/18/2017] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To compare the effects on transcutaneous carbon dioxide tension (Ptco2) of high concentration and titrated oxygen therapy in medical inpatients with morbid obesity who were not selected for a pre-existing diagnosis of obesity hypoventilation syndrome. DESIGN A randomised, crossover trial undertaken between February and September 2015. SETTING Internal medicine service, Wellington Regional Hospital, New Zealand. PARTICIPANTS 22 adult inpatients, aged 16 years or more, with a body mass index exceeding 40 kg/m<sup>2</sup>. INTERVENTIONS Participants received in random order two 60-minute interventions, with a minimum 30-minute washout period between treatments: titrated oxygen therapy (oxygen delivered, if required, via nasal prongs to achieve peripheral oxygen saturation [Spo2] of 88-92%), and high concentration oxygen therapy (delivered via Hudson mask at 8 L/min, without regard to Spo2). Ptco2 and Spo2 were recorded at 10-minute intervals. MAIN OUTCOME MEASURE Ptco2 at 60 minutes, adjusted for baseline. RESULTS Baseline Ptco2 was 45 mmHg or lower for 16 participants with full data (73%). The mean difference in Ptco2 between high concentration and titrated oxygen therapy at 60 minutes was 3.2 mmHg (95% CI, 1.3-5.2 mmHg; P = 0.002). CONCLUSION High concentration oxygen therapy increases Ptco2 in morbidly obese patients. Our findings support guidelines that advocate oxygen therapy, if required in patients with morbid obesity, be titrated to achieve a target Spo2 of 88-92%. CLINICAL TRIAL REGISTRATION Australian New Zealand Clinical Trials Registry, ACTRN12610000522011.
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Affiliation(s)
- Janine Pilcher
- Medical Research Institute of New Zealand, Wellington, New Zealand
| | - Michael Richards
- Medical Research Institute of New Zealand, Wellington, New Zealand
| | - Leonie Eastlake
- Medical Research Institute of New Zealand, Wellington, New Zealand
| | | | - George Bardsley
- Medical Research Institute of New Zealand, Wellington, New Zealand
| | - Sarah Jefferies
- Medical Research Institute of New Zealand, Wellington, New Zealand
| | | | - Mark Weatherall
- Wellington School of Medicine, University of Otago, Wellington, New Zealand
| | - Richard Beasley
- Medical Research Institute of New Zealand, Wellington, New Zealand
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10
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Gill M, Natoli MJ, Vacchiano C, MacLeod DB, Ikeda K, Qin M, Pollock NW, Moon RE, Pieper C, Vann RD. Effects of elevated oxygen and carbon dioxide partial pressures on respiratory function and cognitive performance. J Appl Physiol (1985) 2014; 117:406-12. [DOI: 10.1152/japplphysiol.00995.2013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hyperoxia during diving has been suggested to exacerbate hypercapnic narcosis and promote unconsciousness. We tested this hypothesis in male volunteers (12 at rest, 10 at 75 W cycle ergometer exercise) breathing each of four gases in a hyperbaric chamber. Inspired Po2 (PiO2) was 0.21 and 1.3 atmospheres (atm) without or with an individual subject's maximum tolerable inspired CO2 (PiO2 = 0.055–0.085 atm). Measurements included end-tidal CO2 partial pressure (PetCO2), rating of perceived discomfort (RPD), expired minute ventilation (V̇e), and cognitive function assessed by auditory n-back test. The most prominent finding was, irrespective of PetCO2, that minute ventilation was 8–9 l/min greater for rest or exercise with a PiO2 of 1.3 atm compared with 0.21 atm ( P < 0.0001). For hyperoxic gases, PetCO2 was consistently less than for normoxic gases ( P < 0.01). For hyperoxic hypercapnic gases, n-back scores were higher than for normoxic gases ( P < 0.01), and RPD was lower for exercise but not rest ( P < 0.02). Subjects completed 66 hyperoxic hypercapnic trials without incident, but five stopped prematurely because of serious symptoms (tunnel vision, vision loss, dizziness, panic, exhaustion, or near syncope) during 69 normoxic hypercapnic trials ( P = 0.0582). Serious symptoms during hypercapnic trials occurred only during normoxia. We conclude serious symptoms with hyperoxic hypercapnia were absent because of decreased PetCO2 consequent to increased ventilation.
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Affiliation(s)
| | - Michael J. Natoli
- Department of Anesthesiology, Duke University Medical Center, Durham, North Caroline
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, North Carolina; and
| | - Charles Vacchiano
- Department of Anesthesiology, Duke University Medical Center, Durham, North Caroline
| | - David B. MacLeod
- Department of Anesthesiology, Duke University Medical Center, Durham, North Caroline
| | - Keita Ikeda
- Department of Anesthesiology, Duke University Medical Center, Durham, North Caroline
| | - Michael Qin
- U.S. Naval Submarine Medical Research Laboratory, Groton, Connecticut
| | - Neal W. Pollock
- Divers Alert Network, Durham, North Carolina
- Department of Anesthesiology, Duke University Medical Center, Durham, North Caroline
| | - Richard E. Moon
- Department of Anesthesiology, Duke University Medical Center, Durham, North Caroline
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, North Carolina; and
| | - Carl Pieper
- Center for Aging, Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, North Carolina
| | - Richard D. Vann
- Divers Alert Network, Durham, North Carolina
- Department of Anesthesiology, Duke University Medical Center, Durham, North Caroline
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University Medical Center, Durham, North Carolina; and
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11
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Crocker GH, Jones JH. Effects of oleic acid-induced lung injury on oxygen transport and aerobic capacity. Respir Physiol Neurobiol 2014; 196:43-9. [PMID: 24594105 DOI: 10.1016/j.resp.2014.02.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 02/25/2014] [Accepted: 02/25/2014] [Indexed: 11/18/2022]
Abstract
We tested the hypothesis that oleic-acid (OA) infusion impairs gas exchange, decreases total cardiopulmonary O2 delivery and lowers maximal aerobic capacity ( [Formula: see text] ). We infused 0.05ml OAkg(-1) (∼3ml) and ∼563ml saline into the right atria of four goats [59.1±14.0 (SD) kg] prior to running them on a treadmill at [Formula: see text] 2-h and 1-d following OA-induced acute lung injury, and with no lung injury. Acute lung injury decreased [Formula: see text] , O2 delivery, arterial O2 concentration and arterial O2 partial pressure compared to no lung injury. The [Formula: see text] positively correlated with O2 delivery and inversely correlated with alveolar-arterial O2 partial pressure difference, suggesting that impaired pulmonary gas exchange decreased O2 delivery and uptake. Results indicate OA infusion may be a useful model for acutely impairing pulmonary gas exchange for exercise studies. Seven OA infusions induced smaller chronic gas exchange and arterial O2 partial pressure changes than acute infusion.
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Affiliation(s)
- George H Crocker
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - James H Jones
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
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Wijesinghe M, Perrin K, Healy B, Weatherall M, Beasley R. Randomized controlled trial of high concentration oxygen in suspected community-acquired pneumonia. J R Soc Med 2012; 105:208-16. [PMID: 22532661 DOI: 10.1258/jrsm.2012.110084] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE To determine whether high concentration oxygen increases the PaCO(2) in the treatment of community-acquired pneumonia. DESIGN Randomized controlled clinical trial in which patients received high concentration oxygen (8 L/min via medium concentration mask) or titrated oxygen (to achieve oxygen saturations between 93 and 95%) for 60 minutes. Transcutaneous CO(2) (PtCO(2)) was measured at 0, 20, 40 and 60 minutes. SETTING The Emergency Departments at Wellington, Hutt and Kenepuru Hospitals. PARTICIPANTS 150 patients with suspected community-acquired pneumonia presenting to the Emergency Department. Patients with chronic obstructive pulmonary disease (COPD) or disorders associated with hypercapnic respiratory failure were excluded. MAIN OUTCOME VARIABLES The primary outcome variable was the proportion of patients with a rise in PtCO(2) ≥4 mmHg at 60 minutes. Secondary outcome variables included the proportion of patients with a rise in PtCO(2) ≥8 mmHg at 60 minutes. RESULTS The proportion of patients with a rise in PtCO(2) ≥4 mmHg at 60 minutes was greater in the high concentration oxygen group, 36/72 (50.0%) vs 11/75 (14.7%), relative risk (RR) 3.4 (95% CI 1.9 to 6.2), P < 0.001. The high concentration group had a greater proportion of patients with a rise in PtCO(2) ≥8 mmHg, 11/72 (15.3%) vs 2/75 (2.7%), RR 5.7 (95% CI 1.3 to 25.0), P = 0.007. Amongst the 74 patients with radiological confirmation of pneumonia, the high concentration group had a greater proportion with a rise in PtCO(2) ≥4 mmHg, 20/35 (57.1%) vs 5/39 (12.8%), RR 4.5 (95% CI 1.9 to 10.6) P < 0.001. CONCLUSIONS We conclude that high concentration oxygen therapy increases the PtCO(2) in patients presenting with suspected community-acquired pneumonia. This suggests that the potential increase in PaCO(2) with high concentration oxygen therapy is not limited to COPD, but may also occur in other respiratory disorders with abnormal gas exchange.
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Affiliation(s)
- Meme Wijesinghe
- Medical Research Institute of New Zealand, Wellington 6242, New Zealand
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Wijesinghe M, Williams M, Perrin K, Weatherall M, Beasley R. The Effect of Supplemental Oxygen on Hypercapnia in Subjects With Obesity-Associated Hypoventilation. Chest 2011; 139:1018-1024. [DOI: 10.1378/chest.10-1280] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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14
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LENFANT C, PACE WR. ALTERATIONS OF VENTILATION TO PERFUSION RATIOS DISTRIBUTION ASSOCIATED WITH SUCCESSIVE CLINICAL STAGES OF PULMONARY EMPHYSEMA. J Clin Invest 1996; 44:1566-81. [PMID: 14332169 PMCID: PMC292638 DOI: 10.1172/jci105263] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Chilvers ER, Peters AM, George P, Hughes JM, Allison DJ. Quantification of right to left shunt through pulmonary arteriovenous malformations using 99Tcm albumin microspheres. Clin Radiol 1988; 39:611-4. [PMID: 3243053 DOI: 10.1016/s0009-9260(88)80065-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Calculation of the right-to-left shunt through pulmonary arteriovenous malformations (PAVMs) is important in assessing the effect of therapeutic embolisation or surgical resection. Previously, complicated physiological techniques using radiolabelled inert gases or the 100% oxygen breathing method were required. We describe a new method for quantitating the systemic uptake of intravenously injected 99Tcm albumin microspheres (99Tcm MS) which reflects shunt fraction since these particles do not normally traverse the pulmonary capillary bed. Seven patients with PAVMs were studied and shunt values obtained using 99Tcm MS were validated by simultaneous measurement of shunt fraction using the 100% oxygen method. By comparing radioactive counts in the injection dose to subsequent counts in the right kidney, which was taken as an index of systemic activity, accurate quantification of right-to-left shunt over a wide range of values was obtained (correlation coefficient against 100% oxygen method r = 0.993). The comparison of right kidney counts with total lung counts and total lung counts with injected dose counts, also indicators of shunt fraction, correlated less well with the oxygen method (r = 0.942 and r = 0.88 respectively). Use of 99Tcm labelled microspheres allows simple and precise measurement of right-to-left shunt in patients with PAVMs during routine isotope lung scanning.
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Affiliation(s)
- E R Chilvers
- Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London
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Capacidad residual funcional durante cortos periodos de respiracion de oxigeno al 100% en sujetos sanos. Arch Bronconeumol 1979. [DOI: 10.1016/s0300-2896(15)32569-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Barany JS, Saltzman AR, Klocke RA. Oxygen-related intrapulmonary shunting in obstructive pulmonary disease. Chest 1978; 74:34-8. [PMID: 352633 DOI: 10.1378/chest.74.1.34] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A simple and previously validated double-indicator technique was used to quantitate shunt in patients with obstructive pulmonary disease at rest, during exercise, and during breathing of 100 percent oxygen. The method avoids several inherent difficulties encountered in previous double-indicator techniques and is independent of the fraction of oxygen in the inspired gas. Sixteen resting patients with mild obstructive pulmonary disease were found to have intrapulmonary shunting less than or equal to 0.7 percent of the cardiac output (mean, 0-3 +/- 0.2 percent [SD]). During submaximal exercise, shunting was also low (mean, 0.3 +/- 0.1 percent of cardiac output). After breathing pure oxygen for 30 minutes, 11 patients had similar results; however, in four patients, breathing 100 percent oxygen caused an increase intrapulmonary shunting to 1 to 6 percent of the cardiac output. It is concluded that some patients with obstructive pulmonary disease develop intrapulmonary shunting in response to breathing oxygen.
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Trimble C, Smith DE, Cook TI, Trummer MJ. The effect of supine bedrest upon alveolar-arterial oxygen gradients and intrapulmonary shunting in normal man. J Thorac Cardiovasc Surg 1972. [DOI: 10.1016/s0022-5223(19)41811-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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20
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Davidson FF, Glazier JB, Murray JF. The components of the alveolar-arterial oxygen tension difference in normal subjects and in patients with pneumonia and obstructive lung disease. Am J Med 1972; 52:754-62. [PMID: 4555319 DOI: 10.1016/0002-9343(72)90081-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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21
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Muneyuki M, Ueda Y, Urabe N, Kato H, Shirai K, Inamoto A. Oxygen breathing and QS-QT during postoperative pain relief in man. CANADIAN ANAESTHETISTS' SOCIETY JOURNAL 1972; 19:230-8. [PMID: 5029039 DOI: 10.1007/bf03028289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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22
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Bäcklund L, Tammivaara-Hilty R. Gas exchange in two male age groups in relation to inspiratory oxygen fraction, physical exercise and body posture. Ups J Med Sci 1972; 77:95-111. [PMID: 5070587 DOI: 10.1517/03009734000000015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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23
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Gazioglu K, Condemi JJ, Hyde RW, Kaltreider NL. Effect of isoproterenol on gas exchange during air and oxygen breathing in patients with asthma. Am J Med 1971; 50:185-90. [PMID: 5545455 DOI: 10.1016/0002-9343(71)90147-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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24
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Skillman JJ, Parikh BM, Tanenbaum BJ. Pulmonary arteriovenous admixture. Improvement with albumin and diuresis. Am J Surg 1970; 119:440-7. [PMID: 5437851 DOI: 10.1016/0002-9610(70)90147-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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25
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Der Einflu� von Alter, Geschlecht und Gewicht auf die H�ufigkeit unspezifischer Atemwegserkrankungen. Int Arch Occup Environ Health 1970. [DOI: 10.1007/bf00539044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Skillman JJ, Bushnell LS, Hedley-Whyte J. Peritonitis and respiratory failure after abdominal operations. Ann Surg 1969; 170:122-7. [PMID: 5789524 PMCID: PMC1387609 DOI: 10.1097/00000658-196907000-00013] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Skillman JJ, Bushnell LS, Goldman H, Silen W. Respiratory failure, hypotension, sepsis, and jaundice. A clinical syndrome associated with lethal hemorrhage from acute stress ulceration of the stomach. Am J Surg 1969; 117:523-30. [PMID: 5771525 DOI: 10.1016/0002-9610(69)90011-7] [Citation(s) in RCA: 213] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Fabel H. [Continuous measurement of arterial oxygen pressure in man. Technic and application as well as results in healthy subjects and patients with impaired lung function]. ARCHIV FUR KREISLAUFFORSCHUNG 1968; 57:145-89. [PMID: 5720500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Harlan WR, Still WJ. Hereditary tendinous and tuberous xanthomatosis without hyperlipidemia. A new lipid-storage disorder. N Engl J Med 1968; 278:416-22. [PMID: 5636664 DOI: 10.1056/nejm196802222780803] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Hedley-Whyte J, Pontoppidan H, Morris MJ. The response of patients with respiratory failure and cardiopulmonary disease to different levels of constant volume ventilation. J Clin Invest 1966; 45:1543-54. [PMID: 5925513 PMCID: PMC292836 DOI: 10.1172/jci105461] [Citation(s) in RCA: 53] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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Fruhmann G. Zur quantitativen Feststellung der Lungenfunktion für klinische und arbeitsmedizinische Fragestellungen. ACTA ACUST UNITED AC 1965. [DOI: 10.1007/bf02048003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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