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Kojima Y, Sendo R, Okayama N, Hamasaki J. Fraction of Inspired Oxygen With Low-Flow Versus High-Flow Devices: A Simulation Study. Cureus 2022; 14:e25122. [PMID: 35733468 PMCID: PMC9205390 DOI: 10.7759/cureus.25122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2022] [Indexed: 11/23/2022] Open
Abstract
Purpose: The fraction of inspired oxygen while administering oxygen to patients must be measured as it represents the alveolar oxygen concentration, which is important from a respiratory physiology viewpoint. Therefore, the purpose of this study was to compare the fractions of inspired oxygen obtained through different oxygen delivery devices. Methods: A simulation model of spontaneous respiration was used. The fractions of inspired oxygen obtained through low- and high-flow nasal cannulas and a simple oxygen mask were measured. The fraction of inspired air was measured every second for 30 s after 120 s of oxygen administration. This was measured three times under each condition. Results: With a low-flow nasal cannula, airflow reduced both the intratracheal fraction of inspired oxygen and extraoral oxygen concentration, indicating that exhalatory respiration occurred during rebreathing and may be involved in increasing the intratracheal fraction of inspired oxygen. Conclusion: Oxygen administration during expiratory flow may lead to an increased oxygen concentration in the anatomical dead space, which may be involved in the increase in the fraction of inspired oxygen. With a high-flow nasal cannula, a high fraction of inspired oxygen can be achieved even at a flow rate of 10 L/min. When determining the optimum amount of oxygen, it is necessary to set an appropriate flow rate for patients and specific conditions without being bound by the fraction of inspired oxygen values alone. It might be difficult to estimate the fraction of inspired oxygen while using a low-flow nasal cannula and simple oxygen mask in clinical situations.
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Barnett A, Beasley R, Buchan C, Chien J, Farah CS, King G, McDonald CF, Miller B, Munsif M, Psirides A, Reid L, Roberts M, Smallwood N, Smith S. Thoracic Society of Australia and New Zealand Position Statement on Acute Oxygen Use in Adults: 'Swimming between the flags'. Respirology 2022; 27:262-276. [PMID: 35178831 PMCID: PMC9303673 DOI: 10.1111/resp.14218] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/28/2021] [Accepted: 01/03/2022] [Indexed: 12/14/2022]
Abstract
Oxygen is a life-saving therapy but, when given inappropriately, may also be hazardous. Therefore, in the acute medical setting, oxygen should only be given as treatment for hypoxaemia and requires appropriate prescription, monitoring and review. This update to the Thoracic Society of Australia and New Zealand (TSANZ) guidance on acute oxygen therapy is a brief and practical resource for all healthcare workers involved with administering oxygen therapy to adults in the acute medical setting. It does not apply to intubated or paediatric patients. Recommendations are made in the following six clinical areas: assessment of hypoxaemia (including use of arterial blood gases); prescription of oxygen; peripheral oxygen saturation targets; delivery, including non-invasive ventilation and humidified high-flow nasal cannulae; the significance of high oxygen requirements; and acute hypercapnic respiratory failure. There are three sections which provide (1) a brief summary, (2) recommendations in detail with practice points and (3) a detailed explanation of the reasoning and evidence behind the recommendations. It is anticipated that these recommendations will be disseminated widely in structured programmes across Australia and New Zealand.
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Affiliation(s)
- Adrian Barnett
- Department of Respiratory and Sleep MedicineMater Public HospitalSouth BrisbaneQueenslandAustralia
| | - Richard Beasley
- Medical Research Institute of New Zealand & Capital Coast District Health BoardWellingtonNew Zealand
| | - Catherine Buchan
- Department of Respiratory and Sleep MedicineThe Alfred HospitalMelbourneVictoriaAustralia
- Department of Immunology and Respiratory MedicineMonash UniversityMelbourneVictoriaAustralia
| | - Jimmy Chien
- Department of Respiratory and Sleep MedicineWestmead Hospital, Ludwig Engel Centre for Respiratory Research and University of SydneySydneyNew South WalesAustralia
| | - Claude S. Farah
- Department of Respiratory Medicine, Concord HospitalMacquarie University and University of SydneySydneyNew South WalesAustralia
| | - Gregory King
- Department of Respiratory and Sleep Medicine, Royal North Shore HospitalWoolcock Institute of Medical Research and University of SydneySydneyNew South WalesAustralia
| | - Christine F. McDonald
- Department of Respiratory and Sleep MedicineAustin Health and University of MelbourneMelbourneVictoriaAustralia
| | - Belinda Miller
- Department of Respiratory MedicineThe Alfred Hospital and Monash UniversityMelbourneVictoriaAustralia
| | - Maitri Munsif
- Department of Respiratory and Sleep MedicineAustin Health and University of MelbourneMelbourneVictoriaAustralia
| | - Alex Psirides
- Intensive Care UnitWellington Regional Hospital, Capital and Coast District Health BoardWellingtonNew Zealand
| | - Lynette Reid
- Respiratory MedicineRoyal Hobart HospitalHobartTasmaniaAustralia
| | - Mary Roberts
- Department of Respiratory and Sleep MedicineWestmead Hospital, Ludwig Engel Centre for Respiratory Research and University of SydneySydneyNew South WalesAustralia
| | - Natasha Smallwood
- Department of Respiratory and Sleep MedicineThe Alfred HospitalMelbourneVictoriaAustralia
- Department of Immunology and Respiratory MedicineMonash UniversityMelbourneVictoriaAustralia
| | - Sheree Smith
- School of Nursing and MidwiferyWestern Sydney UniversitySydneyNew South WalesAustralia
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Barnes TH, Singer M. Low cost devices to help in COVID-19. TRENDS IN ANAESTHESIA AND CRITICAL CARE 2021; 38:21-23. [PMID: 38620835 PMCID: PMC8018783 DOI: 10.1016/j.tacc.2021.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 03/28/2021] [Indexed: 10/25/2022]
Affiliation(s)
- Thomas H Barnes
- Emeritus Professor, University of Greenwich, Greenwich Peninsula, London, UK
| | - Mervyn Singer
- Bloomsbury Institute of Intensive Care Medicine, University College London, London, UK
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Li CJ, Law YY, Lin YR, Chen CC, Lin XH, Chuang PC. Impact of Using a Non-Rebreathing Mask in Patients With Respiratory Failure. Am J Med Sci 2021; 361:436-444. [PMID: 33622528 DOI: 10.1016/j.amjms.2020.12.010] [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] [Received: 06/03/2020] [Revised: 10/07/2020] [Accepted: 12/11/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND Liberal oxygen therapy might increase the mortality rate of patients. Non-rebreathing masks (NRM) are a high-flow, non-invasive oxygen device that can provide oxygen concentration up to 95%. This study aimed to determine the impact of using NRM in patients with respiratory failure. METHODS This retrospective cohort study was conducted in four medical institutions in Taiwan from January 2010 to December 2016. The association between mortality and NRM use before receiving ventilator support in patients with respiratory failure in the emergency department was analyzed. Patients were divided into the NRM treatment and no NRM treatment groups. A 1:4 propensity score matching was conducted. Regarding the duration of NRM use, treatments were grouped as 0 h, 0-1 h, 1-2 h, and >2 h. RESULTS A total of 18,749 patients were included, with 1074 using NRM. After propensity score matching, 1028 patients using NRM (0-1 h: 508, 1-2 h: 193, and >2 h: 327) and 4112 patients not using NRM were analyzed. The 30-day mortality rates were 29.1%, 28.5%, 27.5%, and 35.5% in the 0 h, 0-1 h, 1-2 h, and >2 h treatment groups, respectively. Patients with respiratory failure due to pulmonary disease using NRM over 2 h had a higher mortality rate than patients not using NRM (hazard ratio: 1.3, 95% CI: 1.01-1.66). CONCLUSIONS Prolonged use of NRM in patients with respiratory failure due to pulmonary disease possibly increases mortality.
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Affiliation(s)
- Chao-Jui Li
- Department of Emergency Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Yat-Yin Law
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan; Department of Orthopedics, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Yan-Ren Lin
- Institute of Medicine, Chung Shan Medical University, Taichung, Taiwan; Changhua Christian Hospital, Department of Emergency and Critical Care Medicine, Changhua City, Taiwan; Kaohsiung Medical University, School of Medicine, Kaohsiung, Taiwan
| | - Chien-Chih Chen
- Department of Emergency Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Xin-Hong Lin
- Department of Emergency Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Po-Chun Chuang
- Department of Emergency Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
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Vourc'h M, Nicolet J, Volteau C, Caubert L, Chabbert C, Lepoivre T, Senage T, Roussel JC, Rozec B. High-Flow Therapy by Nasal Cannulae Versus High-Flow Face Mask in Severe Hypoxemia After Cardiac Surgery: A Single-Center Randomized Controlled Study-The HEART FLOW Study. J Cardiothorac Vasc Anesth 2019; 34:157-165. [PMID: 31230964 DOI: 10.1053/j.jvca.2019.05.039] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/15/2019] [Accepted: 05/26/2019] [Indexed: 12/26/2022]
Abstract
OBJECTIVE To determine whether high-flow oxygen therapy by nasal cannulae (HFNC) is more effective than a high-flow face mask (HFFM) in severe hypoxemia. DESIGN Randomized, single-center, open-labeled, controlled trial. SETTING University Hospital of Nantes, France. PARTICIPANTS Cardiac surgery patients presenting oxygen saturation <96% with Venturi mask 50%. INTERVENTION Oxygenation by HFNC (45 L/min, FIO2 100%) or Hudson RCI non-rebreather face mask with a reservoir bag (15 L/min). MEASUREMENTS AND MAIN RESULTS The co-primary outcomes were the PaO2/FIO2 ratio at 1 and 24 hours. In the intent-to-treat analysis (90 patients), the mean (standard deviation) PaO2/FIO2 ratios were: after 1 hour, 113.4 (50.2) in HFFM versus 137.8 (57.0) in HFNC (mean difference 24.4, CI 97.5% [2.9-45.9], p = 0.03), and after 24 hours, 106.9 (62.6) in HFFM versus 129.9 (54.0) in HFNC (mean difference 23.0, CI 97.5% [1.5-44.6], p = 0.04). After adjustment on baseline PaO2/FIO2, this difference persisted at 24 hours (p = 0.04). For secondary outcomes, the PaO2/FIO2 ratio after 6 hours was 108.7 (47.9) in HFFM versus 136.0 (45.2) in HFNC (p = 0.01), without difference after 48 hours (p = 0.95). Refractory hypoxemia requiring noninvasive ventilation occurred in 13 (28%) patients in HFNC versus 24 (56%) patients in HFFM (p = 0.007). The HFNC improved satisfaction (p = 0.0002) and reduced mucus dryness (p = 0.003) compared with HFFM. CONCLUSION In patients with severe hypoxemia after cardiac surgery, PaO2/FIO2 at 1 and 24 hours were higher and the use of noninvasive ventilation was reduced in HFNC compared with HFFM.
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Affiliation(s)
- Mickael Vourc'h
- Intensive Care Unit of Cardiothoracic Surgery, Department of Anesthesia and Critical Care, Hôpital Laennec, University Hospital of Nantes, Nantes, France.
| | - Johanna Nicolet
- Intensive Care Unit of Cardiothoracic Surgery, Department of Anesthesia and Critical Care, Hôpital Laennec, University Hospital of Nantes, Nantes, France
| | - Christelle Volteau
- Department of Methodology and Biostatistics, Department of Research Promotion, University Hospital of Nantes, Nantes, France
| | - Laurene Caubert
- Intensive Care Unit of Cardiothoracic Surgery, Department of Anesthesia and Critical Care, Hôpital Laennec, University Hospital of Nantes, Nantes, France
| | - Claude Chabbert
- Intensive Care Unit of Cardiothoracic Surgery, Department of Anesthesia and Critical Care, Hôpital Laennec, University Hospital of Nantes, Nantes, France
| | - Thierry Lepoivre
- Intensive Care Unit of Cardiothoracic Surgery, Department of Anesthesia and Critical Care, Hôpital Laennec, University Hospital of Nantes, Nantes, France
| | - Thomas Senage
- Cardiovascular and Thoracic Surgery Unit, Hôpital Laënnec, University Hospital of Nantes, Nantes, France
| | - Jean-Christian Roussel
- Cardiovascular and Thoracic Surgery Unit, Hôpital Laënnec, University Hospital of Nantes, Nantes, France
| | - Bertrand Rozec
- Intensive Care Unit of Cardiothoracic Surgery, Department of Anesthesia and Critical Care, Hôpital Laennec, University Hospital of Nantes, Nantes, France
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Rolfe S, Paul F. Oxygen therapy in adult patients. Part 2: promoting safe and effective practice in patients' care and management. BRITISH JOURNAL OF NURSING (MARK ALLEN PUBLISHING) 2018; 27:988-995. [PMID: 30235025 DOI: 10.12968/bjon.2018.27.17.988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The assessment, care and management of patients requiring oxygen therapy are key aspects of a nurse's role. Although oxygen therapy is an important treatment for many clinical conditions, it carries risks and complications; therefore, nurses and other health professionals have a responsibility to ensure safe and effective practice along with maintaining and developing their knowledge and skills in this therapy. The relevant aspects of physiology and pathophysiology were explored and discussed in part one of this article ( Rolfe and Paul, 2018 ). The aims of the second part are to discuss: (1) the indications for oxygen therapy; (2) the principles of assessment, care and management of adult patients requiring oxygen therapy; and (3) recommendations for the safe and effective use of oxygen devices, along with the potential complications.
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Affiliation(s)
- Sandy Rolfe
- Respiratory Nurse Specialist, NHS Tayside, and Clinical Academic Lecturer, School of Nursing and Health Sciences, University of Dundee
| | - Fiona Paul
- Lecturer, School of Nursing and Health Sciences, University of Dundee
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O'Driscoll BR, Howard LS, Earis J, Mak V. BTS guideline for oxygen use in adults in healthcare and emergency settings. Thorax 2017; 72:ii1-ii90. [DOI: 10.1136/thoraxjnl-2016-209729] [Citation(s) in RCA: 316] [Impact Index Per Article: 45.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/03/2017] [Accepted: 02/12/2017] [Indexed: 12/15/2022]
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Beasley R, Chien J, Douglas J, Eastlake L, Farah C, King G, Moore R, Pilcher J, Richards M, Smith S, Walters H. Thoracic Society of Australia and New Zealand oxygen guidelines for acute oxygen use in adults: 'Swimming between the flags'. Respirology 2015; 20:1182-91. [PMID: 26486092 PMCID: PMC4654337 DOI: 10.1111/resp.12620] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 06/17/2015] [Indexed: 01/07/2023]
Abstract
The purpose of the Thoracic Society of Australia and New Zealand guidelines is to provide simple, practical evidence-based recommendations for the acute use of oxygen in adults in clinical practice. The intended users are all health professionals responsible for the administration and/or monitoring of oxygen therapy in the management of acute medical patients in the community and hospital settings (excluding perioperative and intensive care patients), those responsible for the training of such health professionals, and both public and private health care organizations that deliver oxygen therapy.
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Affiliation(s)
- Richard Beasley
- Medical Research Institute of New ZealandWellington, New Zealand
- Wellington Regional Hospital, Capital and Coast District Health BoardWellington, New Zealand
| | - Jimmy Chien
- Department of Respiratory and Sleep Medicine, Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, University of Sydney at Westmead HospitalSydney, New South Wales, Australia
| | - James Douglas
- Thoracic Program, The Prince Charles HospitalBrisbane, Queensland, Australia
| | - Leonie Eastlake
- Medical Research Institute of New ZealandWellington, New Zealand
| | - Claude Farah
- Department of Respiratory Medicine, Concord HospitalSydney, New South Wales, Australia
- Physiology and Imaging Group, Woolcock Institute of Medical ResearchSydney, New South Wales, Australia
- Sydney Medical School, University of SydneySydney, New South Wales, Australia
- Australian School of Advanced Medicine, Macquarie UniversitySydney, New South Wales, Australia
| | - Gregory King
- Physiology and Imaging Group, Woolcock Institute of Medical ResearchSydney, New South Wales, Australia
- Sydney Medical School, University of SydneySydney, New South Wales, Australia
- Department of Respiratory Medicine, Royal North Shore HospitalSydney, New South Wales, Australia
| | - Rosemary Moore
- Institute for Breathing and Sleep, Austin HealthMelbourne, Victoria, Australia
| | - Janine Pilcher
- Medical Research Institute of New ZealandWellington, New Zealand
- Wellington Regional Hospital, Capital and Coast District Health BoardWellington, New Zealand
- School of Biological Sciences, Victoria University of WellingtonWellington, New Zealand
| | - Michael Richards
- Medical Research Institute of New ZealandWellington, New Zealand
| | - Sheree Smith
- School of Nursing and Midwifery, University of Western SydneySydney, New South Wales, Australia
| | - Haydn Walters
- CRE for Chronic Respiratory Disease, University of TasmaniaHobart, Tasmania, Australia
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Tancredi FB, Lajoie I, Hoge RD. Test-retest reliability of cerebral blood flow and blood oxygenation level-dependent responses to hypercapnia and hyperoxia using dual-echo pseudo-continuous arterial spin labeling and step changes in the fractional composition of inspired gases. J Magn Reson Imaging 2015; 42:1144-57. [PMID: 25752936 DOI: 10.1002/jmri.24878] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/09/2015] [Indexed: 01/16/2023] Open
Abstract
PURPOSE To assess the reproducibility of blood oxygenation level-dependent / cerebral blood flow (BOLD/CBF) responses to hypercapnia/hyperoxia using dual-echo pseudo-continuous arterial spin labeling (pCASL) and step changes in inspired doses. MATERIALS AND METHODS Eight subjects were scanned twice, within 24 hours, using the same respiratory manipulation and imaging protocol. Imaging comprised a 5-minute anatomical acquisition, allowing segmentation of the gray matter (GM) tissue for further analysis, and an 18-minute pCASL functional scan. Hypercapnia/hyperoxia were induced by increasing the fraction of inspired CO2 to 5% and inspired O2 to 60%, alternately. Reproducibility of BOLD and CBF pCASL measures was assessed by computing the inter-session coefficient of variation (CV) of the respective signals in GM. RESULTS BOLD and CBF measures in GM were robust and consistent, yielding CV values below 10% for BOLD hypercapnic/hyperoxic responses (which averaged 1.9 ± 0.1% and 1.14 ± 0.02%) and below 20% for the CBF hypercapnic response (which averaged 35 ± 2 mL/min/100g). The CV for resting CBF was 3.5%. CONCLUSION It is possible to attain reproducible measures of the simultaneous BOLD and CBF responses to blood gases, within a reasonable scan time and with whole brain coverage, using a simple respiratory manipulation and dual-echo pCASL.
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Affiliation(s)
- Felipe B Tancredi
- Université de Montréal Institut de génie biomédical Département de physiologie C.P. 6128, Succursale Centre-ville Montréal, Québec, Canada.,Centre de recherche de l'institut universitaire de gériatrie de Montréal Unité de neuroimagerie fonctionnelle 4545, Ch. Queen Mary Montréal, Québec, Canada.,Hospital Israelita Albert Einstein Imagem Av. Albert Einstein, 627, São Paulo, SP, Brazil
| | - Isabelle Lajoie
- Université de Montréal Institut de génie biomédical Département de physiologie C.P. 6128, Succursale Centre-ville Montréal, Québec, Canada.,Centre de recherche de l'institut universitaire de gériatrie de Montréal Unité de neuroimagerie fonctionnelle 4545, Ch. Queen Mary Montréal, Québec, Canada
| | - Richard D Hoge
- Université de Montréal Institut de génie biomédical Département de physiologie C.P. 6128, Succursale Centre-ville Montréal, Québec, Canada.,Centre de recherche de l'institut universitaire de gériatrie de Montréal Unité de neuroimagerie fonctionnelle 4545, Ch. Queen Mary Montréal, Québec, Canada
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Tancredi FB, Lajoie I, Hoge RD. A simple breathing circuit allowing precise control of inspiratory gases for experimental respiratory manipulations. BMC Res Notes 2014; 7:235. [PMID: 24725848 PMCID: PMC4005461 DOI: 10.1186/1756-0500-7-235] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 04/09/2014] [Indexed: 11/27/2022] Open
Abstract
Background Respiratory manipulations modulating blood flow and oxygenation levels have become an important component of modern functional MRI applications. Manipulations often consist of temporarily switching inspired fractions of CO2 and O2; and have typically been performed using simple oxygen masks intended for applications in respiratory therapy. However, precise control of inspired gas composition is difficult using this type of mask due to entrainment of room air and resultant dilution of inspired gases. We aimed at developing a gas delivery apparatus allowing improved control over the fractional concentration of inspired gases, to be used in brain fMRI studies. Findings The breathing circuit we have conceived allowed well controlled step changes in FiO2 and FiCO2, at moderate flow rates achievable on standard clinical flow regulators. In a two run test inside the scanner we demonstrate that tightly controlled simple gas switching manipulations can afford good intra-subject reproducibility of induced hyperoxia/hypercapnia responses. Although our approach requires a non-vented mask fitting closely to the subject’s face, the circuit ensures a continuous supply of breathable air even if the supply of medical gases is interrupted, and is easily removable in case of an emergency. The apparatus we propose is also compact and MRI compatible, allowing subject placement in confined spaces such as an MRI scanner for brain examinations. Conclusions We have reported a new approach for the controlled administration of medical gases, and describe an implementation of the breathing circuit that is MRI compatible and uses commercially available parts. The resultant apparatus allows simple, safe and precise manipulations of FiO2 and FiCO2.
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Affiliation(s)
- Felipe B Tancredi
- Institut de génie biomédical, Département de physiologie, Université de Montréal, C,P, 6128, Succursale Centre-ville, Montréal, Québec H3C 3J7, Canada.
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Impact of gas delivery systems on imaging studies of human cerebral blood flow. Radiol Res Pract 2013; 2013:694803. [PMID: 24392225 PMCID: PMC3874307 DOI: 10.1155/2013/694803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 11/08/2013] [Accepted: 11/13/2013] [Indexed: 11/30/2022] Open
Abstract
Purpose. To compare a semiopen breathing circuit with a non-rebreathing (Hudson mask) for MRI experiments involving gas delivery. Methods and Materials. Cerebral blood flow (CBF) was measured by quantitative phase contrast angiography of the internal carotid and basilar arteries in 18 volunteers (20–31 years). In 8 subjects, gases were delivered via a standard non-rebreathing (Hudson mask). In 10 subjects, gases were delivered using a modified “Mapleson A” semiopen anesthetic gas circuit and mouthpiece. All subjects were given 100% O2, medical air, and carbogen gas (95% O2 and 5% CO2) delivered at 15 L/min in a random order. Results. The Hudson mask group showed significant increases in CBF in response to increased FiCO2 compared to air (+9.8%). A small nonsignificant reduction in CBF (−2.4%) was seen in response to increased inspired concentrations of oxygen (FiO2). The Mapleson A group showed significantly larger changes in CBF in response to both increased inspired concentrations of carbon dioxide (FiCO2) (+32.2%, P < 0.05) and FiO2 (−14.6%, P < 0.01). Conclusions. The use of an anaesthetic gas delivery circuit avoids entrainment of room air and rebreathing effects that may otherwise adversely affect the experimental results.
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Resucitación fetal intrauterina. CLINICA E INVESTIGACION EN GINECOLOGIA Y OBSTETRICIA 2013. [DOI: 10.1016/j.gine.2012.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Nicolet J, Poulard F, Baneton D, Rigal JC, Blanloeil Y. [High-flow nasal oxygen for severe hypoxemia after cardiac surgery]. ACTA ACUST UNITED AC 2011; 30:331-4. [PMID: 21398081 DOI: 10.1016/j.annfar.2011.01.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 01/28/2011] [Indexed: 01/31/2023]
Abstract
OBJECTIVES High-flow nasal oxygen (Optiflow™) is validated in paediatric intensive care but not in adults' patients for severe hypoxemia. The aim of this study was to evaluate this oxygen system delivery in adults' patients for postoperative hypoxemia after cardiac surgery. STUDY DESIGN Prospective, open study for evaluation of medical practice. PATIENTS AND METHODS Patients operated upon for cardiac surgery with immediate postoperative hypoxemia characterized by SpO(2) <0.96 with 50% oxygen with a Venturi mask were treated with the high-flow nasal oxygen system (O group) when it was available or with the classical high-flow oxygen face mask (M group). Gas exchanges were measured at the end of the surgery, at the beginning of the treatment and 1 hour, 6 hours after the inclusion and at day 1 and 2 post-treatment. Parameters studied were: duration of hypoxemia, duration of ICU stay, postoperative pneumonia occurrence, requirement of re-intubation, non invasive ventilation and catecholamine. Tolerance was evaluated with measurement of pain (visual scale), satisfaction (visual scale), and dryness of mouth. RESULTS Forty patients were included, 19 in group O, 21 in group M. Patient's characteristics did not differ between the two groups before treatment. There were no significant differences between groups for duration of hypoxemia (3.8±2.2 days in O group versus 4.3±2.3 days in M group), duration of hypoxemia, duration of ICU stay, postoperative pneumonia occurrence, requirement of re-intubation, non invasive ventilation and catecholamine. Pain was not significantly different between groups, satisfaction was better (P<0.001) and mouth drier (P<0.001) in group O than in group M. CONCLUSION These results give good arguments for an improvement in gas exchange and better tolerance of high-flow nasal oxygen (Optiflow™) versus classical high-flow oxygen face mask in postoperative cardiac patients. These results must be confirmed by a randomised study with a larger population.
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Affiliation(s)
- J Nicolet
- Service d'anesthésie-réanimation chirurgicale, hôpital Laennec, BP 1005, boulevard Jacques-Monod, 44093 Nantes cedex 1, France.
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Velayudhareddy S, Kirankumar H. Management of foetal asphyxia by intrauterine foetal resuscitation. Indian J Anaesth 2010; 54:394-9. [PMID: 21189876 PMCID: PMC2991648 DOI: 10.4103/0019-5049.71032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Management of foetal distress is a subject of gynaecological interest, but an anaesthesiologist should know about resuscitation, because he should be able to treat the patient, whenever he is directly involved in managing the parturient patient during labour analgesia and before an emergency operative delivery. Progressive asphyxia is known as foetal distress; the foetus does not breathe directly from the atmosphere, but depends on maternal circulation for its oxygen requirement. The oxygen delivery to the foetus depends on the placental (maternal side), placental transfer and foetal circulation. Oxygen transport to the foetus is reduced physiologically during uterine contractions in labour. Significant impairment of oxygen transport to the foetus, either temporary or permanent may cause foetal distress, resulting in progressive hypoxia and acidosis. Intrauterine foetal resuscitation comprises of applying measures to a mother in active labour, with the intention of improving oxygen delivery to the distressed foetus to the base line, if the placenta is functioning normally. These measures include left lateral recumbent position, high flow oxygen administration, tocolysis to reduce uterine contractions, rapid intravenous fluid administration, vasopressors for correction of maternal hypotension and amnioinfusion for improving uterine blood flow. Intrauterine Foetal Resuscitation measures are easy to perform and do not require extensive resources, but the results are encouraging in improving the foetal well-being. The anaesthesiologist plays a major role in the application of intrauterine foetal resuscitation measures.
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Affiliation(s)
- S. Velayudhareddy
- Department of Anaesthesiology, Rajeev Gandhi Institute of Medical Sciences, Kadapa, Andhra Pradesh, India
| | - H Kirankumar
- Department of Anaesthesiology, Rajeev Gandhi Institute of Medical Sciences, Kadapa, Andhra Pradesh, India
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Eastwood GM, Peck L, Young H, Prowle J, Jones D, Bellomo R. Oxygen administration and monitoring for ward adult patients in a teaching hospital. Intern Med J 2010; 41:784-8. [PMID: 20561099 DOI: 10.1111/j.1445-5994.2010.02286.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIM The aims of this study were to describe oxygen administration and respiratory monitoring of ward patients in a tertiary teaching hospital, and to assess differences in characteristics and outcomes between patients who are receiving versus are not receiving oxygen. METHODS Prospective clinical audit of all non-ventilated adult ward patients in a tertiary teaching hospital in Melbourne, Victoria on 26 August 2009. RESULTS All 323 eligible patients were audited (medical 218, surgical 105). At assessment, 76 patients (24%) were on oxygen therapy and of these, 57 patients (74%) received oxygen by nasal prongs. Overall, oxygen saturation was documented in 301 (93.2%) patients and respiratory rate (RR) documented in 283 patients (87.6%). Patients receiving oxygen had a lower median SpO(2) (94% vs 96%, P < 0.0001), higher median RR (20/min vs 18/min, P < 0.0005); and were older (68.8 v 63.1 years, P= 0.0094). The in-hospital mortality of patients receiving oxygen therapy was 15.8% compared with 5.3% for those not on oxygen (P < 0.0056). CONCLUSION Oxygen is administered to one-quarter of ward patients in our hospital. Oxygen saturation and RR are not documented in approximately 10% of patients. Oxygen therapy in ward patients identifies individuals with increased mortality. Continuing educational interventions to increase awareness of the high-risk status of these patients and strategies to detect patients at risk of hypoxaemia are needed.
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Affiliation(s)
- G M Eastwood
- Austin Hospital, Heidelberg, Victoria, Australia.
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Eastwood GM, O’Connell B, Gardner A, Considine J. Patients’ and nurses’ perspectives on oxygen therapy: a qualitative study. J Adv Nurs 2009; 65:634-41. [DOI: 10.1111/j.1365-2648.2008.04933.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Standley TDA, Smith HL, Brennan LJ, Wilkins IA, Bradley PG, Barrera Groba C, Davey AJ, Menon DK, Wheeler DW. Room air dilution of heliox given by facemask. Intensive Care Med 2008; 34:1469-76. [DOI: 10.1007/s00134-008-1064-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Accepted: 02/18/2008] [Indexed: 11/25/2022]
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Abstract
The administration of a known concentration of oxygen is an important part of routine care of the sick patient. Many devices are currently available. The actual concentration of oxygen that can be delivered by these devices can be affected by several factors, both from the patient as well as the device itself. Measuring the F(i)o(2) delivered to the lungs in vivo can be both difficult and potentially uncomfortable for the subjects. We constructed a model using a resuscitation manikin, a ventilator and a set of bellows to simulate ventilation. With this model we tested a series of devices - variable performance, fixed performance and high flow - at two fixed tidal volumes. The respiratory rate was increased and its effect on the oxygen concentration assessed. Variable performance systems such as the Hudson mask deliver a significantly reduced oxygen concentration at high respiratory rates. Fixed performance systems delivering 24-40% oxygen deliver appropriate oxygen concentrations across the range of respiratory rates, whereas those delivering 60% show a reduction in performance. High flow systems show no failure of performance at increased respiratory rates.
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Affiliation(s)
- T A J Wagstaff
- Magill Department of Anaesthesia, Intensive Care and Pain Management, Chelsea and Westminster Hospital, London, UK.
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Grissom CK, Weaver LK, Clemmer TP, Morris AH. Theoretical advantage of oxygen treatment for combat casualties during medical evacuation at high altitude. ACTA ACUST UNITED AC 2006; 61:461-7. [PMID: 16917469 DOI: 10.1097/01.ta.0000221699.71596.9d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Colin K Grissom
- Critical Care Medicine, LDS Hospital, Salt Lake City, Utah 84143, USA.
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