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Larsson A, Östberg E, Edmark L. Arterial partial pressure of oxygen as a marker of airway closure does not correlate with the efficacy of pre-oxygenation: A prospective cohort study. Eur J Anaesthesiol 2023; 40:699-706. [PMID: 37395501 DOI: 10.1097/eja.0000000000001869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
BACKGROUND The prerequisites for the early formation of anaesthesia-related atelectasis are pre-oxygenation with its resulting high alveolar oxygen content, and airway closure. Airway closure increases with age, so it seems counterintuitive that atelectasis formation during anaesthesia does not. One proposed explanation is that pre-oxygenation is impaired in the elderly by airway closure present in the waking state. The extent of airway closure cannot be assessed at the bedside, but arterial partial pressure of oxygen ( Pa O 2 ) as a surrogate variable of the resulting ventilation to perfusion mismatch can. OBJECTIVE The primary aim was to test the hypothesis that a decreased efficacy of pre-oxygenation, measured as the fraction of end-tidal oxygen (F E' O 2 ) after 3 min of pre-oxygenation, correlates with decreased Pa O 2 on room air. We also re-investigated the influence on F E' O 2 by age. DESIGN Prospective observational study. SETTING Two regional hospitals, Västerås and Köping County Hospitals, Västmanland, Sweden, between 30 October 2018 and 17 September 2021. PARTICIPANTS We included 120 adults aged 40 to 79 years presenting for elective noncardiac surgery. INTERVENTION An arterial blood gas was sampled before commencing pre-oxygenation. RESULTS No linear correlation was found between F E' O 2 at 3 min and Pa O 2 or age (Pearson's r = -0.038, P = 0.684; and Pearson's r = -0.113, P = 0.223, respectively). The mean ± SD F E' O 2 at 3 min for the population studied was 0.87 ± 0.05. CONCLUSION The lack of correlation between F E' O 2 at 3 min and Pa O 2 or age during pre-oxygenation has implications for further studies concerning the interaction between airway closure and atelectasis. After 3 min of pre-oxygenation, F E' O 2 , even in the elderly, indicated a high enough alveolar oxygen concentration to promote atelectasis after induction, therefore, it is still unclear why atelectasis formation diminishes after middle age. TRIAL REGISTRATION ClinicalTrials.gov NCT03395782.
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Affiliation(s)
- Alexander Larsson
- From the Department of Anaesthesia and Intensive Care (AL, EÖ, LE) and Region Vastmanland - Uppsala University, Centre for Clinical Research, Vastmanland Hospital Vasteras, Sweden (AL, EÖ, LE)
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West J, Levine R, Raggi J, Nguyen DT, Oliver M, Caputo N, Sakles J. Time to Renitrogenation After Maximal Denitrogenation in Healthy Volunteers in the Supine and Sitting Positions. West J Emerg Med 2022; 23:926-930. [DOI: 10.5811/westjem.2022.5.55378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 05/28/2022] [Indexed: 11/15/2022] Open
Abstract
Introduction: Prior to intubation, preoxygenation is performed to denitrogenate the lungs and create an oxygen reservoir. After oxygen is removed, it is unclear whether renitrogenation after preoxygenation occurs faster in the supine vs the sitting position.
Methods: We enrolled 80 healthy volunteers who underwent two preoxygenation and loss of preoxygenation procedures (one while supine and one while sitting) via bag-valve-mask ventilation with spontaneous breathing. End-tidal oxygen (ETO2) measurements were recorded as fraction of expired oxygen prior to preoxygenation, at the time of adequate preoxygenation (ETO2 >85%), and then every five seconds after the oxygen was removed until the ETO2 values reached their recorded baseline.
Results: The mean ETO2 at completion of preoxygenation was 86% (95% confidence interval 85-88%). Volunteers in both the supine and upright position lost >50% of their denitrogenation in less than 60 seconds. Within 25 seconds, all subjects had an ETO2 of <70%. Complete renitrogenation, defined as return to baseline ETO2, occurred in less than 160 seconds for all volunteers.
Conclusion: Preoxygenation loss, or renitrogenation, occurred rapidly after oxygen removal and was not different in the supine and sitting positions. After maximal denitrogenation in healthy volunteers, renitrogenation occurred rapidly after oxygen removal and was not different in the supine and sitting positions.
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Affiliation(s)
- Jason West
- NYC Health + Hospitals
- Lincoln, Department of Emergency Medicine, Bronx, New York
| | - Rykiel Levine
- NYC Health + Hospitals
- Lincoln, Department of Emergency Medicine, Bronx, New York
| | - Jason Raggi
- NYC Health + Hospitals
- Lincoln, Department of Emergency Medicine, Bronx, New York
| | - Du-Thuyen Nguyen
- Royal Prince Alfred Hospital, Sydney, Department of Emergency Medicine, New South Wales, Australia
| | - Matthew Oliver
- Royal Prince Alfred Hospital, Sydney, Department of Emergency Medicine, New South Wales, Australia; RPA Green Light Institute for Emergency Care, Sydney, New South Wales, Australia
| | - Nicholas Caputo
- NYC Health + Hospitals
- Lincoln, Department of Emergency Medicine, Bronx, New York
| | - John Sakles
- University of Arizona College of Medicine, Department of Emergency Medicine, Tucson, Arizona
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SCARAMUZZO G, OTTAVIANI I, VOLTA CA, SPADARO S. Mechanical ventilation and COPD: from pathophysiology to ventilatory management. Minerva Med 2022; 113:460-470. [DOI: 10.23736/s0026-4806.22.07974-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Abstract
The lungs are continually subjected to noxious and inert substances, are immunologically active, and are in a constant state of damage and repair. This makes the pulmonary system particularly vulnerable to diseases of aging. Aging can be understood as random molecular damage that is unrepaired and accumulates over time, resulting in cellular defects and tissue dysfunction. The breakdown of cellular mechanisms, including stem cell exhaustion, genomic instability, telomere attrition, epigenetic alteration, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, altered intercellular communication, and changes in the extracellular matrix is thought to advance the aging process itself. Chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and cancers illustrate a pathologic breakdown in these mechanisms beyond normal aging. The immune system becomes less effective with advancing age. There is a low-level state of chronic inflammation termed inflammaging which is thought to be driven by immunosenescence, the changes in the innate and adaptive immune systems with advancing age that lead to dysregulation and decreased effectiveness of the immune system. These processes of aging lead to expected changes in the form and function of the respiratory system, most notably a loss of lung elasticity, decrease in respiratory muscle strength, increase in ventilation-perfusion mismatching, and stiffening of the vasculature. The astute clinician is aware of these expected findings and does not often attribute dyspnea to aging alone. Maintaining a low threshold to investigate for comorbid disease and understanding how pulmonary disease presents differently in the elderly than in younger adults can improve clinical outcomes. © 2022 American Physiological Society. Compr Physiol 12:3509-3522, 2022.
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Affiliation(s)
- Julia Budde
- New York City Health and Hospitals/Metropolitan Hospital, New York, New York, USA
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Garland A, Hopton P. Airway closure in anaesthesia and intensive care. BJA Educ 2022; 22:126-130. [PMID: 35531076 PMCID: PMC9073299 DOI: 10.1016/j.bjae.2021.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2021] [Indexed: 11/15/2022] Open
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Islam MS, Larpruenrudee P, Saha SC, Pourmehran O, Paul AR, Gemci T, Collins R, Paul G, Gu Y. How severe acute respiratory syndrome coronavirus-2 aerosol propagates through the age-specific upper airways. PHYSICS OF FLUIDS (WOODBURY, N.Y. : 1994) 2021; 33:081911. [PMID: 34552312 PMCID: PMC8450910 DOI: 10.1063/5.0061627] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 07/24/2021] [Indexed: 05/22/2023]
Abstract
The recent outbreak of the COVID-19 causes significant respirational health problems, including high mortality rates worldwide. The deadly corona virus-containing aerosol enters the atmospheric air through sneezing, exhalation, or talking, assembling with the particulate matter, and subsequently transferring to the respiratory system. This recent outbreak illustrates that the severe acute respiratory syndrome (SARS) coronavirus-2 is deadlier for aged people than for other age groups. It is evident that the airway diameter reduces with age, and an accurate understanding of SARS aerosol transport through different elderly people's airways could potentially help the overall respiratory health assessment, which is currently lacking in the literature. This first-ever study investigates SARS COVID-2 aerosol transport in age-specific airway systems. A highly asymmetric age-specific airway model and fluent solver (ANSYS 19.2) are used for the investigation. The computational fluid dynamics measurement predicts higher SARS COVID-2 aerosol concentration in the airway wall for older adults than for younger people. The numerical study reports that the smaller SARS coronavirus-2 aerosol deposition rate in the right lung is higher than that in the left lung, and the opposite scenario occurs for the larger SARS coronavirus-2 aerosol rate. The numerical results show a fluctuating trend of pressure at different generations of the age-specific model. The findings of this study would improve the knowledge of SARS coronavirus-2 aerosol transportation to the upper airways which would thus ameliorate the targeted aerosol drug delivery system.
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Affiliation(s)
- Mohammad S. Islam
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney (UTS), 15 Broadway, Ultimo, New South Wales 2007, Australia
- Authors to whom correspondence should be addressed: and
| | - Puchanee Larpruenrudee
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney (UTS), 15 Broadway, Ultimo, New South Wales 2007, Australia
| | - Suvash C. Saha
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney (UTS), 15 Broadway, Ultimo, New South Wales 2007, Australia
- Authors to whom correspondence should be addressed: and
| | - Oveis Pourmehran
- School of Mechanical Engineering, The University of Adelaide, Adelaide, South Australia 5005, Australia and Department of Surgery—Otolaryngology Head and Neck Surgery, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Akshoy Ranjan Paul
- Department of Applied Mechanics, Motilal Nehru National Institute of Technology Allahabad, Prayagraj 211004, Uttar Pradesh, India
| | | | - Richard Collins
- Biomechanics International, Cranberry Township, Pennsylvania 16066, USA
| | - Gunther Paul
- James Cook University, Australian Institute of Tropical Health and Medicine, Townsville, Queensland 4810, Australia
| | - Yuantong Gu
- School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane 4000, Australia
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Yamamoto K, Mase K, Kihara K, Ishikawa A, Ozaki K. Effects of postural differences on intrapleural pressure during chest wall compression in healthy males. J Phys Ther Sci 2021; 33:132-136. [PMID: 33642687 PMCID: PMC7897531 DOI: 10.1589/jpts.33.132] [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: 09/28/2020] [Accepted: 11/02/2020] [Indexed: 11/24/2022] Open
Abstract
[Purpose] This study aimed to investigate the difference in intrapleural pressure
between the supine and lateral decubitus positions during manual chest wall compression.
[Participants and Methods] Eight healthy males participated in this study. The same
physiotherapist performed chest wall compression on participants lying supine, and on
their right and left sides. We noted changes in intrapleural pressure and lung volume in
each participant during quiet breathing and chest wall compression. [Results] During chest
wall compression, intrapleural pressure at the end-expiratory lung volume and the
end-inspiratory lung volume were lower in the right and left decubitus positions than in
the supine position. We observed the following low inflection points in the
pressure-volume loops during chest wall compression: all participants in the supine
position, no participants in the right decubitus position, and two participants in the
left decubitus position. [Conclusion] Chest wall compression in the bilateral decubitus
positions may not cause excessive intrapleural pressure on the airway and alveoli as
compared to chest wall compression in the supine position.
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Affiliation(s)
- Kenta Yamamoto
- Department of Rehabilitation, Konan Medical Center: 1-5-16 Kamokogahara, Higashinada, Kobe, Hyogo 658-0064, Japan.,Department of Disability and Health, Hirosaki University Graduate School of Health Sciences, Japan
| | - Kyoshi Mase
- Department of Physical Therapy, Faculty of Science, Nursing and Rehabilitation, Konan Women's University, Japan
| | | | - Akira Ishikawa
- Department of Disability and Health, Hirosaki University Graduate School of Health Sciences, Japan
| | - Kohei Ozaki
- Department of Anesthesiology and Critical Care Medicine, Kobe Century Memorial Hospital, Japan
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Domnik NJ, Walsted ES, Langer D. Clinical Utility of Measuring Inspiratory Neural Drive During Cardiopulmonary Exercise Testing (CPET). Front Med (Lausanne) 2020; 7:483. [PMID: 33043023 PMCID: PMC7530180 DOI: 10.3389/fmed.2020.00483] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 07/16/2020] [Indexed: 12/18/2022] Open
Abstract
Cardiopulmonary exercise testing (CPET) has traditionally included ventilatory and metabolic measurements alongside electrocardiographic characterization; however, research increasingly acknowledges the utility of also measuring inspiratory neural drive (IND) through its surrogate measure of diaphragmatic electromyography (EMGdi). While true IND also encompasses the activation of non-diaphragmatic respiratory muscles, the current review focuses on diaphragmatic measurements, providing information about additional inspiratory muscle groups for context where appropriate. Evaluation of IND provides mechanistic insight into the origins of dyspnea and exercise limitation across pathologies; yields valuable information reflecting the integration of diverse mechanical, chemical, locomotor, and metabolic afferent signals; and can help assess the efficacy of therapeutic interventions. Further, IND measurement during the physiologic stress of exercise is uniquely poised to reveal the underpinnings of physiologic limitations masked during resting and unloaded breathing, with important information provided not only at peak exercise, but throughout exercise protocols. As our understanding of IND presentation across varying conditions continues to grow and methods for its measurement become more accessible, the translation of these principles into clinical settings is a logical next step in facilitating appropriate and nuanced management tailored to each individual's unique physiology. This review provides an overview of the current state of understanding of IND measurement during CPET: its origins, known patterns of behavior and links with dyspnea in health and major respiratory diseases, and the possibility of expanding this approach to applications beyond exercise.
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Affiliation(s)
| | - Emil S. Walsted
- Respiratory Research Unit, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Daniel Langer
- Research Group for Rehabilitation in Internal Disorders, Respiratory Rehabilitation and Respiratory Division, Department of Rehabilitation Sciences, University Hospital Leuven, KU Leuven, Leuven, Belgium
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Hedenstierna G, Tokics L, Reinius H, Rothen HU, Östberg E, Öhrvik J. Higher age and obesity limit atelectasis formation during anaesthesia: an analysis of computed tomography data in 243 subjects. Br J Anaesth 2020; 124:336-344. [DOI: 10.1016/j.bja.2019.11.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/29/2019] [Accepted: 11/23/2019] [Indexed: 11/30/2022] Open
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Darquenne C, Prisk GK. The Effect of Aging on Aerosol Bolus Deposition in the Healthy Adult Lung: A 19-Year Longitudinal Study. J Aerosol Med Pulm Drug Deliv 2019; 33:133-139. [PMID: 31613688 DOI: 10.1089/jamp.2019.1566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: While it is recognized that peripheral lung structure and ventilation heterogeneity change with age, the effects of age on aerosol deposition in the healthy adult lung is largely unknown. Methods: A series of aerosol bolus inhalations were repeatedly performed in four healthy subjects over a period of 19 years (years = 0, 9, 15 and 19). For each series, a bolus of 1 μm particles was inhaled at penetration volumes (Vp) ranging from 200 to 1200 mL. Aerosol bolus deposition (DE), dispersion (H), and mode shift (MS) were calculated along with the rate of increase in these parameters with increasing Vp (slope-DE, slope-H, and slope-MS). Results: Slope-DE significantly increased from 0.040 ± 0.014 (mean ± standard deviation) at year 0 to 0.069 ± 0.007%/mL at year 19 (p = 0.02) with no significant difference in DE at shallow depth (Vp = 200 mL; 14% ± 4% at year 0 vs. 15% ± 7% at year 19, p = 0.25). There was no significant effect of age on either slope-H (0.44 ± 0.05 at year 0 vs. 0.47 ± 0.09 mL/mL at year 19, p = 0.6) or dispersion at shallow depth (192 ± 36 mL at year 0 vs. 220 ± 54 mL at year 19, p = 0.2). Slope-MS became significantly more negative with increasing age (-0.096 ± 0.044 at year 0 vs. -0.171 ± 0.027 mL/mL at year 19, p = 0.001) with no significant difference in MS at shallow depth (12 ± 10 at year 0 vs. 7 ± 15 mL at year 19, p = 0.3). Conclusions: These data suggest that (1) peripheral deposition increases with aging in the healthy lung, likely as a result of increasing closing volume with age; (2) alterations in the mechanical properties of healthy adult lungs with age occur uniformly; and (3) the significant increase in the magnitude of MS-slope with age is likely due to the concomitant increase in peripheral deposition and possible alterations in flow sequencing.
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Affiliation(s)
- Chantal Darquenne
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - G Kim Prisk
- Department of Medicine, University of California, San Diego, La Jolla, California
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11
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Dentice RL, Elkins MR, Verschuer J, Eberl S, Dwyer G, Bye PTP. Side lying during nebulisation can significantly improve apical deposition in healthy adults and adults with mild cystic fibrosis lung disease: a randomised crossover trial. BMC Pulm Med 2019; 19:128. [PMID: 31311524 PMCID: PMC6636004 DOI: 10.1186/s12890-019-0886-7] [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: 01/08/2019] [Accepted: 06/25/2019] [Indexed: 11/17/2022] Open
Abstract
Background In people with and without Cystic Fibrosis (CF), does side lying during nebulisation change: the proportion of the dose loaded in the nebuliser that is deposited in the lungs; the uniformity of deposition throughout the lungs; or the apical drug density as a percentage of the drug density in the remaining lung? Do these effects differ depending on the degree of lung disease present? Methods A randomised crossover trial with concealed allocation, intention-to-treat analysis and blinded assessors, involving 39 adults: 13 healthy, 13 with mild CF lung disease (FEV1 > 80%pred), and 13 with more advanced CF lung disease (FEV1 < 80%pred). In random order, 4 mL of nebulised radioaerosol was inhaled in upright sitting and in alternate right and left side lying at 2-min intervals, for 20 min. Results Compared to sitting upright, lung deposition and the uniformity of deposition were not significantly altered by side lying in any of the three groups. In sitting, the density of the deposition was significantly less in the apical regions than in the rest of the lung in all participants. Side lying significantly improved apical deposition in healthy adults (MD, 13%; 95% CI, 7 to 19), and in minimal CF lung disease (MD, 4%; 95% CI, 1 to 7) but not in advanced disease (MD, 4%; 95% CI, − 2 to 9). Conclusion Alternating between right and left side lying during nebulisation significantly improves apical deposition in healthy adults and in adults with mild CF lung disease, without substantial detriment to overall deposition. Trial registration ACTRN12611000674932 (Healthy), ACTRN12611000672954 (CF) Retrospectively registered 4/7/2011. Electronic supplementary material The online version of this article (10.1186/s12890-019-0886-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ruth L Dentice
- Physiotherapy Department, Royal Prince Alfred Hospital, Sydney, Australia.
| | - Mark R Elkins
- Centre for Education & Workforce Development, Sydney Local Health District, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia
| | - Jordan Verschuer
- Department of Molecular Imaging, Royal Prince Alfred Hospital, Sydney, Australia
| | - Stefan Eberl
- Department of Molecular Imaging, Royal Prince Alfred Hospital, Sydney, Australia
| | - Genevieve Dwyer
- Physiotherapy Program, Western Sydney University, Sydney, Australia.
| | - Peter T P Bye
- Sydney Medical School, University of Sydney, Sydney, Australia.,Department of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, Australia
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Abstract
Abstract
Editor’s Perspective
What We Already Know about This Topic
What This Article Tells Us That Is New
Background
Anesthesia is increasingly common in elderly and overweight patients and prompted the current study to explore mechanisms of age- and weight-dependent worsening of arterial oxygen tension (Pao2).
Methods
This is a primary analysis of pooled data in patients with (1) American Society of Anesthesiologists (ASA) classification of 1; (2) normal forced vital capacity; (3) preoxygenation with an inspired oxygen fraction (Fio2) more than 0.8 and ventilated with Fio2 0.3 to 0.4; (4) measurements done during anesthesia before surgery. Eighty patients (21 women and 59 men, aged 19 to 69 yr, body mass index up to 30 kg/m2) were studied with multiple inert gas elimination technique to assess shunt and perfusion of poorly ventilated regions (low ventilation/perfusion ratio []) and computed tomography to assess atelectasis.
Results
Pao2/Fio2 was lower during anesthesia than awake (368; 291 to 470 [median; quartiles] vs. 441; 397 to 462 mm Hg; P = 0.003) and fell with increasing age and body mass index. Log shunt was best related to a quadratic function of age with largest shunt at 45 yr (r2 =0.17, P = 0.001). Log shunt was linearly related to body mass index (r2 = 0.15, P < 0.001). A multiple regression analysis including age, age2, and body mass index strengthened the association further (r2 = 0.27). Shunt was highly associated to atelectasis (r2 = 0.58, P < 0.001). Log low showed a linear relation to age (r2 = 0.14, P = 0.001).
Conclusions
Pao2/Fio2 ratio was impaired during anesthesia, and the impairment increased with age and body mass index. Shunt was related to atelectasis and was a more important cause of oxygenation impairment in middle-aged patients, whereas low, likely caused by airway closure, was more important in elderly patients. Shunt but not low increased with increasing body mass index. Thus, increasing age and body mass index impaired gas exchange by different mechanisms during anesthesia.
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Klimeš F, Voskrebenzev A, Gutberlet M, Kern A, Behrendt L, Kaireit TF, Czerner C, Renne J, Wacker F, Vogel-Claussen J. Free-breathing quantification of regional ventilation derived by phase-resolved functional lung (PREFUL) MRI. NMR IN BIOMEDICINE 2019; 32:e4088. [PMID: 30908743 DOI: 10.1002/nbm.4088] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 02/11/2019] [Accepted: 02/12/2019] [Indexed: 06/09/2023]
Abstract
PURPOSE To test the feasibility of regional fully quantitative ventilation measurement in free breathing derived by phase-resolved functional lung (PREFUL) MRI in the supine and prone positions. In addition, the influence of T2 * relaxation time on ventilation quantification is assessed. METHODS Twelve healthy volunteers underwent functional MRI at 1.5 T using a 2D triple-echo spoiled gradient echo sequence allowing for quantitative measurement of T2 * relaxation time. Minute ventilation (ΔV) was quantified by conventional fractional ventilation (FV) and the newly introduced regional ventilation (VR), which corrects volume errors due to image registration. ΔVFV versus ΔVVR and ΔVVR versus ΔVVR with T2 * correction were compared using Bland-Altman plots and correlation analysis. The repeatability and physiological plausibility of all measurements were tested in the supine and prone positions. RESULTS On global and regional scales a strong correlation was observed between ΔVFV versus ΔVVR and ΔVVR versus ΔVVRT2* (r > 0.93); however, regional Bland-Altman analysis showed systematic differences (p < 0.0001). Unlike ΔVVRT2* , ΔVVR and ΔVFV showed expected physiologic anterior-posterior gradients, which decreased in the supine but not in the prone position at second measurement during 3 min in the same position. For all quantification methods a moderate repeatability (coefficient of variation <20%) of ventilation was found. CONCLUSION A fully quantified regional ventilation measurement using ΔVVR in free breathing is feasible and shows physiologically plausible results. In contrast to conventional ΔVFV, volume errors due to image registration are eliminated with the ΔVVR approach. However, correction for the T2 * effect remains challenging.
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Affiliation(s)
- F Klimeš
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - A Voskrebenzev
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - M Gutberlet
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - A Kern
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - L Behrendt
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - T F Kaireit
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - C Czerner
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - J Renne
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - F Wacker
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
| | - J Vogel-Claussen
- Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Hanover, Germany
- Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hanover, Germany
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14
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Smith JR, Borlaug BA, Olson TP. Exercise Ventilatory Efficiency in Older and Younger Heart Failure Patients With Preserved Ejection Fraction. J Card Fail 2019; 25:278-285. [PMID: 30822511 DOI: 10.1016/j.cardfail.2019.02.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 01/31/2019] [Accepted: 02/20/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND Patients with heart failure with preserved ejection fraction (HFpEF) exhibit pulmonary abnormalities, but the studies to date have reported wide variability in the ventilatory equivalent for carbon dioxide (V̇E/V̇CO2) slope. It is possible that aging may contribute to that variability. We sought to compare ventilatory efficiency and its components in older and younger HFpEF patients during exercise. METHODS AND RESULTS Eighteen older (O; 80 ± 4 y) and 19 younger (Y; 59 ± 7 y) HFpEF patients performed cardiopulmonary exercise testing to volitional fatigue. Measurements of arterial blood gases were used to derive VD/VT, dead space ventilation, and alveolar ventilation. V̇E/V̇CO2 slope was greater in older compared with younger HFpEF patients (O 36 ± 7vs Y 31 ± 7; P = .04). At peak exercise, older HFpEF exhibited greater VD/VT compared with younger HFpEF (O 0.37 ± 0.10vs Y 0.28 ± 0.10; P < .01), whereas PaCO2 was not different between groups (P = .58). V̇E and alveolar ventilation were similar (P > .23), but dead space ventilation was greater in older compared with younger HFpEF at peak exercise (P = .04). CONCLUSIONS Older HFpEF patients exhibit greater ventilatory inefficiency resulting from elevated physiologic dead space during peak exercise compared with younger HFpEF patients. These results suggest that aging can worsen the pathophysiologic mechanisms underlying ventilatory efficiency during exercise in HFpEF.
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Affiliation(s)
- Joshua R Smith
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester Minnesota.
| | - Barry A Borlaug
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester Minnesota
| | - Thomas P Olson
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester Minnesota
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Nilsen K, Thien F, Thamrin C, Ellis MJ, Prisk GK, King GG, Thompson BR. Early onset of airway derecruitment assessed using the forced oscillation technique in subjects with asthma. J Appl Physiol (1985) 2019; 126:1399-1408. [PMID: 30702975 DOI: 10.1152/japplphysiol.00534.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Derecruitment of air spaces in the lung occurs when airways close during exhalation and is related to ventilation heterogeneity and symptoms in asthma. The forced oscillation technique has been used to identify surrogate measures of airway closure via the reactance (Xrs) versus lung volume relationship. This study used a new algorithm to identify derecruitment from the Xrs versus lung volume relationship from a slow vital capacity maneuver. We aimed to compare two derecruitment markers on the Xrs versus volume curve, the onset reduction of Xrs (DR1vol) and the onset of more rapid reduction of Xrs (DR2vol), between control and asthmatic subjects. We hypothesized that the onset of DR1vol and DR2vol occurred at higher lung volume in asthmatic subjects. DR1vol and DR2vol were measured in 18 subjects with asthma and 18 healthy controls, and their relationships with age and height were examined using linear regression. In the control group, DR1vol and DR2vol increased with age (r2 = 0.68, P < 0.001 and r2 = 0.71, P < 0.001, respectively). DR1vol and DR2vol in subjects with asthma [76.58% of total lung capacity (TLC) and 56.79%TLC, respectively] were at higher lung volume compared with control subjects (46.1 and 37.69%TLC, respectively) (P < 0.001). DR2vol correlated with predicted values of closing capacity (r = 0.94, P < 0.001). This study demonstrates that derecruitment occurs at two points along the Xrs-volume relationship. Both derecruitment points occurred at significantly higher lung volumes in subjects with asthma compared with healthy control subjects. This technique offers a novel way to measure the effects of changes in airways/lung mechanics. NEW & NOTEWORTHY This study demonstrates that the forced oscillation technique can be used to identify two lung volume points where lung derecruitment occurs: 1) where derecruitment is initiated and 2) where onset of rapid derecruitment commences. Measurements of derecruitment increase with age. The onset of rapid derecruitment was highly correlated with predicted closing capacity. Also, the initiation and rate of derecruitment are significantly altered in subjects with asthma.
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Affiliation(s)
- Kris Nilsen
- Central Clinical School, Monash University , Melbourne, Victoria , Australia.,Allergy Immunology and Respiratory Medicine, The Alfred Hospital , Melbourne, Victoria , Australia
| | - Francis Thien
- Eastern Health Clinical School, Monash University , Melbourne, Victoria , Australia.,Box Hill Hospital , Melbourne, Victoria , Australia
| | - Cindy Thamrin
- Woolcock Institute of Medical Research, University of Sydney , Sydney, New South Wales , Australia.,Department of Respiratory Medicine, Royal North Shore Hospital , St. Leonards, New South Wales , Australia
| | - Matt J Ellis
- Allergy Immunology and Respiratory Medicine, The Alfred Hospital , Melbourne, Victoria , Australia
| | - G Kim Prisk
- Department of Medicine, Division of Physiology, University of California , San Diego, California
| | - Gregory G King
- Woolcock Institute of Medical Research, University of Sydney , Sydney, New South Wales , Australia.,Department of Respiratory Medicine, Royal North Shore Hospital , St. Leonards, New South Wales , Australia
| | - Bruce R Thompson
- Central Clinical School, Monash University , Melbourne, Victoria , Australia.,Allergy Immunology and Respiratory Medicine, The Alfred Hospital , Melbourne, Victoria , Australia
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16
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Marini JJ. Acute Lobar Atelectasis. Chest 2018; 155:1049-1058. [PMID: 30528423 DOI: 10.1016/j.chest.2018.11.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 11/15/2018] [Accepted: 11/17/2018] [Indexed: 01/06/2023] Open
Abstract
Lobar atelectasis (or collapse) is an exceedingly common, rather predictable, and potentially pathogenic companion to many forms of acute illness, postoperative care, and chronic debility. Readily diagnosed by using routine chest imaging and bedside ultrasound, the consequences from lobar collapse may be minor or serious, depending on extent, mechanism, patient vulnerability, abruptness of onset, effectiveness of hypoxic vasoconstriction, and compensatory reserves. Measures taken to reduce secretion burden, assure adequate secretion clearance, maintain upright positioning, reverse lung compression, and sustain lung expansion accord with a logical physiologic rationale. Both classification and logical approaches to prophylaxis and treatment of lobar atelectasis derive from a sound mechanistic knowledge of its causation.
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Affiliation(s)
- John J Marini
- Pulmonary & Critical Care Medicine Divisions, Regions Hospital & University of Minnesota, Minneapolis/St. Paul, MN.
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17
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Comparison of two methods of determining lung de-recruitment, using the forced oscillation technique. Eur J Appl Physiol 2018; 118:2213-2224. [PMID: 30062516 DOI: 10.1007/s00421-018-3949-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/21/2018] [Indexed: 10/28/2022]
Abstract
Airway closure has proved to be important in a number of respiratory diseases and may be the primary functional defect in asthma. A surrogate measure of closing volume can be identified using the forced oscillation technique (FOT), by performing a deflation maneuver and examining the resultant reactance (Xrs) lung volume relationship. This study aims to determine if a slow vital capacity maneuver can be used instead of this deflation maneuver and compare it to existing more complex techniques. Three subject groups were included in the study; healthy (n = 29), asthmatic (n = 18), and COPD (n = 10) for a total of 57 subjects. Reactance lung volume curves were generated via FOT recordings during two different breathing manoeuvres (both pre and post bronchodilator). The correlation and agreement between surrogate closing volume (Volcrit) and reactance (Xrscrit) at this volume was analysed. The changes in Volcrit and Xrscrit pre and post bronchodilator were also analysed. Across all three subject groups, the two different measures of Volcrit were shown to be statistically equivalent (p > 0.05) and demonstrated a strong fit to the data (R2 = 0.49, 0.78, 0.59, for asthmatic, COPD and healthy subject groups, respectively). A bias was evident between the two measurements of Xrscrit with statistically different means (p < 0.05). However, the two measurements of Xrscrit displayed the same trends. In conclusion, we have developed an alternative technique for measuring airway closure from FOT recordings. The technique delivers equivalent and possibly more sensitive results to previous methods while being simple and easily performed by the patient.
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Abstract
Growth of the segment of the population older than 65 years has led to intensified interest in understanding the biology of aging. This article is focused on age-related alterations in lung structure that produce predictable changes in physiologic function, both at rest and during exercise. Increased insight into the physiology of the healthy aging lung should ultimately lead to improved methods of lung function assessment in the elderly (defined as those older than 65 years) as well as better understanding of the manifestations and possibly even the treatment of geriatric lung disease.
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Affiliation(s)
- Gwen S Skloot
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box #1232, New York, NY, USA.
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19
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Littleton SW, Tulaimat A. The effects of obesity on lung volumes and oxygenation. Respir Med 2017; 124:15-20. [DOI: 10.1016/j.rmed.2017.01.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/13/2017] [Accepted: 01/17/2017] [Indexed: 10/20/2022]
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20
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Lutfi MF. The physiological basis and clinical significance of lung volume measurements. Multidiscip Respir Med 2017; 12:3. [PMID: 28194273 PMCID: PMC5299792 DOI: 10.1186/s40248-017-0084-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 01/02/2017] [Indexed: 11/10/2022] Open
Abstract
From a physiological standpoint, the lung volumes are either dynamic or static. Both subclasses are measured at different degrees of inspiration or expiration; however, dynamic lung volumes are characteristically dependent on the rate of air flow. The static lung volumes/capacities are further subdivided into four standard volumes (tidal, inspiratory reserve, expiratory reserve, and residual volumes) and four standard capacities (inspiratory, functional residual, vital and total lung capacities). The dynamic lung volumes are mostly derived from vital capacity. While dynamic lung volumes are essential for diagnosis and follow up of obstructive lung diseases, static lung volumes are equally important for evaluation of obstructive as well as restrictive ventilatory defects. This review intends to update the reader with the physiological basis, clinical significance and interpretative approaches of the standard static lung volumes and capacities.
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Affiliation(s)
- Mohamed Faisal Lutfi
- Department of Physiology, Faculty of Medicine and Health Sciences, Al-Neelain University, Khartoum, Sudan
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21
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Affiliation(s)
| | - J I Alexander
- University Department of Anæsthesia, Western Infirmary, Glasgow
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22
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Tomlinson SP, Lo JKW, Tilley DG. Computer Simulation of Human Interaction with Underwater Breathing Equipment. Proc Inst Mech Eng H 2016. [DOI: 10.1243/pime_proc_1994_208_295_02] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A mathematical model of the human respiratory system is being developed in order to simulate manned diving operations using various types of breathing equipment. A simulation study is presented of a human diving to a depth of 50 m, using a semi-closed re-breathing system with two different oxygen flow settings. A gas supply with 32.5 per cent oxygen concentration results in a safe dive whereas a 60 per cent setting indicates a dangerous diving condition. Typical respiratory model input data are illustrated for the lung, together with dimensional details for the re-breathing counterlung. The simulation results show variations in alveolar and pleural pressures, gas concentrations and partial pressures in the equipment and in the human respiratory system.
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Affiliation(s)
- S P Tomlinson
- Fluid Power Centre, School of Mechanical Engineering, University of Bath
| | - J K W Lo
- Fluid Power Centre, School of Mechanical Engineering, University of Bath
| | - D G Tilley
- Fluid Power Centre, School of Mechanical Engineering, University of Bath
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23
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Sukul P, Trefz P, Kamysek S, Schubert JK, Miekisch W. Instant effects of changing body positions on compositions of exhaled breath. J Breath Res 2015; 9:047105. [PMID: 26582820 DOI: 10.1088/1752-7155/9/4/047105] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Concentrations of exhaled volatile organic compounds (VOCs) may depend not only on biochemical or pathologic processes but also on physiological parameters. As breath sampling may be done in different body positions, effects of the sampling position on exhaled VOC concentrations were investigated by means of real-time mass spectrometry. Breaths from 15 healthy volunteers were analyzed in real-time by PTR-ToF-MS-8000 during paced breathing (12/min) in a continuous side-stream mode. We applied two series of body positions (setup 1: sitting, standing, supine, and sitting; setup 2: supine, left lateral, right lateral, prone, and supine). Each position was held for 2 min. Breath VOCs were quantified in inspired and alveolar air by means of a custom-made algorithm. Parallel monitoring of hemodynamics and capnometry was performed noninvasively. In setup 1, when compared to the initial sitting position, normalized mean concentrations of isoprene, furan, and acetonitrile decreased by 24%, 26%, and 9%, respectively, during standing and increased by 63%, 36%, and 10% during lying mirroring time profiles of stroke volume and pET-CO2. In contrast, acetone and H2S concentrations remained almost constant. In setup 2, when compared to the initial supine position, mean alveolar concentrations of isoprene and furan increased significantly up to 29% and 16%, respectively, when position was changed from lying on the right side to the prone position. As cardiac output and stroke volume decreased at that time, the reasons for the observed concentrations changes have to be linked to the ventilation/perfusion ratio or compartmental distribution rather than to perfusion alone. During final postures, all VOC concentrations, hemodynamics, and pET-CO2 returned to baseline. Exhaled blood-borne VOC profiles changed due to body postures. Changes depended on cardiac stroke volume, origin, compartmental distribution and physico-chemical properties of the substances. Patients' positions and cardiac output have to be controlled when concentrations of breath VOCs are to be interpreted in terms of biomarkers.
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Affiliation(s)
- Pritam Sukul
- Department of Anesthesiology and Intensive Care Medicine, Rostock Medical Breath Research Analytics and Technologies (ROMBAT), University Medicine Rostock, Schillingallee 35, D-18057 Rostock, Germany
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Karbing DS, Thomsen LP, Moesgaard J, Andreassen S, Toft E, Thorgaard P, Rees SE. Model-based measurement of gas exchange in healthy subjects using ALPE essential--influence of age, posture and gender. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2013:2441-4. [PMID: 24110220 DOI: 10.1109/embc.2013.6610033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ALPE Essential device for model-based measurement of pulmonary gas exchange status may be a useful alternative to current methods for diagnosing, monitoring and evaluating treatment related to pulmonary gas exchange. In this study, shunt and ventilation/perfusion mismatch were measured with ALPE Essential in 106 healthy subjects with the aim of investigating the influence of age, posture and gender on gas exchange parameters and evaluating the test-retest reliability of the measurements. Age and gender did not have statistically significant influence on gas exchange parameters, although there was a tendency for poorer matching of ventilation and perfusion with age. Posture was shown to be important when measuring gas exchange parameters. Absolute measurement reliability was acceptable with future studies in patients being necessary for accurate evaluation of relative reliability.
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Stark RJ, Shekerdemian LS. Estimating intracardiac and extracardiac shunting in the setting of complex congenital heart disease. Ann Pediatr Cardiol 2014; 6:145-51. [PMID: 24688231 PMCID: PMC3957443 DOI: 10.4103/0974-2069.115259] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Complex congenital heart disease (CHD) is associated with significant morbidity worldwide. Managing hypoxemia in these populations can be difficult, particularly in the setting of cyanotic CHD. However, the presence of additional extracardiac shunts secondary to acute respiratory disease can be very challenging to manage. Before understanding how to deal with hypoxemia in patients with dual shunts, one needs to understand the physiology and diagnosis related to the individual shunts and apply this knowledge to the patient as a whole.
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Affiliation(s)
- Ryan J Stark
- Department of Pediatric Critical Care, Texas Children's Hospital and Baylor College of Medicine, Houston, Texas, USA
| | - Lara S Shekerdemian
- Department of Pediatric Critical Care, Texas Children's Hospital and Baylor College of Medicine, Houston, Texas, USA
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Thomas P, Paratz J, Lipman J. Seated and semi-recumbent positioning of the ventilated intensive care patient - effect on gas exchange, respiratory mechanics and hemodynamics. Heart Lung 2014; 43:105-11. [PMID: 24594247 DOI: 10.1016/j.hrtlng.2013.11.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 11/25/2013] [Accepted: 11/26/2013] [Indexed: 10/25/2022]
Abstract
OBJECTIVES To compare the effect of semi-recumbent and sitting positions on gas exchange, respiratory mechanics and hemodynamics in patients weaning from mechanical ventilation. BACKGROUND Upright positions are encouraged during rehabilitation of the critically ill but there effects have not been well described. METHODS A prospective, randomized, cross-over trial was conducted. Subjects were passively mobilized from supine into a seated position (out of bed) and from supine to a semi-recumbent position (>45° backrest elevation in bed). Arterial blood gas (PaO2/FiO2, PaO2, SaO2, PaCO2 and A-a gradient), respiratory mechanics (VE,VT, RR, Cdyn, RR/VT) and hemodynamic measurements (HR, MABP) were collected in supine and at 5 min and 30 min after re-positioning. RESULTS Thirty-four intubated and ventilated subjects were enrolled. The angle of backrest inclination in sitting (67 ± 5°) was greater than gained with semi-recumbent positioning (50 ± 5°, p < 0.001). There were no clinically important changes in arterial blood gas, respiratory mechanic or hemodynamic values due to either position. CONCLUSIONS Neither position resulted in significant changes in respiratory and hemodynamic parameters. Both positions can be applied safely in patients being weaned from ventilation.
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Affiliation(s)
- Peter Thomas
- Department of Physiotherapy, Royal Brisbane and Women's Hospital, Brisbane, Australia.
| | - Jennifer Paratz
- Burns Trauma and Critical Care Research Centre, University of Queensland, Brisbane, Australia
| | - Jeffrey Lipman
- Burns Trauma and Critical Care Research Centre, University of Queensland, Brisbane, Australia; Department of Intensive Care Medicine, Royal Brisbane and Women's Hospital, Brisbane, Australia
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Polverino F, Santoriello C, Andò F, Girbino G, Cappetta D, D'Agostino B, Vatrella A, Polverino M, Milic-Emili J. Recumbent deoxygenation in mild/moderate liver cirrhosis: the "clinodeoxia". The ortho-clino paradigm. Respir Med 2014; 108:1040-8. [PMID: 24785153 DOI: 10.1016/j.rmed.2014.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 04/01/2014] [Accepted: 04/05/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND While the effects of postural change on arterial oxygenation have been well documented in normal subjects, and attributed to the relationship of closing volume (CV) to the tidal volume, in liver cirrhosis such postural changes have been evaluated mainly in a rare, peculiar clinical end-stage condition which is characterized by increased dyspnea shifting from supine to upright position ("platypnea"). The latter is associated with worsening of PaO2 ("orthodeoxia"). We evaluated the effects of postural changes on arterial oxygenation in patients affected by mild/moderate liver cirrhosis. METHODS We performed pulmonary function tests and arterial blood gas evaluation in sitting and supine positions in 22 patients with mild/moderate liver cirrhosis, biopsy-proved, and 22 matched non-smokers control subjects. RESULTS Recumbency elicited a decrease of PaO2 (Δ(sup-sit)PaO2) in 19 out of 22 controls and in all but one cirrhotics. The magnitude of this postural change was significantly (p = 0.04) greater in cirrhotics (9.6 ± 5.3%) compared to controls (6.7 ± 3.7%). In the subset of cirrhotics younger than 60 yrs and with PaO2 greater than 80 mmHg in sitting position, the Δ(sup-sit)PaO2 in recumbency further increased to 12 ± 5.8%, significantly (p = 0.014) greater than in same subgroup of controls (7.1 ± 3.8%). CONCLUSIONS In mild/moderate liver cirrhosis the postural variations in PaO2 follow the normal trends, but are of greater magnitude probably as a consequence of hypoventilated units of lung for postural and disease-linked tidal airway closure, resulting in more pronounced recumbent hypoxemia ("clinodeoxia").
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Affiliation(s)
- Francesca Polverino
- Department of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; The Lovelace Respiratory Research Institute, Albuquerque, NM, USA; Pulmonary Department, University of Parma, Parma, Italy.
| | - Carlo Santoriello
- Department of Pulmonary Medicine, Cava de' Tirreni Hospital, Cava de' Tirreni, Italy
| | - Filippo Andò
- Lung Diseases Institute, University of Messina Medical School, Messina, Italy
| | - Giuseppe Girbino
- Lung Diseases Institute, University of Messina Medical School, Messina, Italy
| | - Donato Cappetta
- Department of Experimental Medicine, Second University of Naples, Naples, Italy
| | - Bruno D'Agostino
- Department of Experimental Medicine, Second University of Naples, Naples, Italy
| | | | - Mario Polverino
- Department of Pulmonary Medicine, Cava de' Tirreni Hospital, Cava de' Tirreni, Italy; Lung Diseases Institute, University of Messina Medical School, Messina, Italy
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29
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Incidence and prediction of inadequate preoxygenation before induction of anaesthesia. ACTA ACUST UNITED AC 2014; 33:e55-8. [DOI: 10.1016/j.annfar.2013.12.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Accepted: 12/30/2013] [Indexed: 11/22/2022]
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Grocott HP. From the Journal archives: Airway closure and lung volumes in surgical positions. Can J Anaesth 2014; 61:383-6. [PMID: 24442988 DOI: 10.1007/s12630-013-0098-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 12/11/2013] [Indexed: 11/25/2022] Open
Abstract
AUTHORS Douglas B. Craig, W.M. Wahba, Hillary Don CITATION Can Anaesth Soc J 1971; 18: 92-9. PURPOSE Surgery and anesthesia expose patients to moderate and sometimes extreme positioning changes that are often unphysiological. The purpose of this article is to highlight and contextualize a seminal study from the Journal archives that explores the effect of several commonly utilized surgical positions (supine, Trendelenburg and lithotomy) and age on basic lung volumes as well as the volume at which small airway closure (AC) (also known as closing volume [CV]) occurs. These factors were examined with the aim of determining which patient position variables could be of clinical significance to gas exchange in the perioperative period. PRINCIPAL FINDINGS This work showed that supine positioning, when compared with the seated position, results in a decrease of all lung volumes and capacities, including functional residual capacity (FRC) and CV. Trendelenburg positioning further decreases FRC, with no further changes induced by lithotomy positioning. Age is a clinically important factor in AC, occurring within the tidal volume range at a lower age when supine as compared with the seated position. CONCLUSIONS The work of Drs. D. Craig et al. published in the Journal more than 40 years ago was seminal to our understanding of how patient positioning has an important influence on lung volumes and on the age-related relationship between FRC and CV.
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Affiliation(s)
- Hilary P Grocott
- Departments of Anesthesia & Perioperative Medicine and Surgery, St. Boniface Hospital, University of Manitoba, CR3008 - 369 Tache Avenue, Winnipeg, MB, R2H 2A6, Canada,
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Hochhegger B, Meirelles GS, Irion K, Zanetti G, Garcia E, Moreira J, Marchiori E. The chest and aging: radiological findings. J Bras Pneumol 2013; 38:656-65. [PMID: 23147059 DOI: 10.1590/s1806-37132012000500016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 09/05/2012] [Indexed: 01/03/2023] Open
Abstract
In the elderly (conventionally defined as individuals ≥ 60 years of age), it is often difficult to establish what normality is, because of the numerous anatomical and physiological modifications that occur during the aging process. As a result, the greatest challenge is to differentiate between the normal aging process and the onset of disease. Healthy elderly people commonly present borderline findings on chest imaging. We systematically reviewed the medical literature on the subject, covering the period between 1950 and 2011, including articles in Portuguese, English, French, Italian, and Spanish. We searched the PubMed, LILACS, and SciELO databases, using the search terms "age", "aging", "lung", "thorax", "chest", "X-ray", "radiography", "pulmonary", and "computed tomography"-as well as their corresponding translations-in various combinations. We included only original or review articles on aging-related chest imaging findings. In broad terms, aging results in physiological modifications that must be recognized so as not to be erroneously interpreted as pathological.
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Affiliation(s)
- Bruno Hochhegger
- Department of Pulmonology, Santa Casa Hospital Complex in Porto Alegre, UFSCPA, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil.
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Oxygeneer, maar niet als weleer. Crit Care 2013. [DOI: 10.1007/s12426-013-0091-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Ax M, Karlsson LL, Sanchez-Crespo A, Lindahl SGE, Linnarsson D, Mure M, Petersson J. Regional lung ventilation in humans during hypergravity studied with quantitative SPECT. Respir Physiol Neurobiol 2013; 189:558-64. [PMID: 24004984 DOI: 10.1016/j.resp.2013.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 07/23/2013] [Accepted: 08/15/2013] [Indexed: 11/28/2022]
Abstract
Recently we challenged the view that arterial desaturation during hypergravity is caused by redistribution of blood flow to dependent lung regions by demonstrating a paradoxical redistribution of blood flow towards non-dependent regions. We have now quantified regional ventilation in 10 healthy supine volunteers at normal and three times normal gravity (1G and 3G). Regional ventilation was measured with Technegas ((99m)Tc) and quantitative single photon emission computed tomography (SPECT). Hypergravity caused arterial desaturation, mean decrease 8%, p<0.05 vs. 1G. The ratio for mean ventilation per voxel for non-dependent and dependent lung regions was 0.81±0.12 during 1G and 1.63±0.35 during 3G (mean±SD), p<0.0001. Thus, regional ventilation was shifted from dependent to non-dependent regions. We suggest that arterial desaturation during hypergravity is caused by quantitatively different redistributions of blood flow and ventilation. To our knowledge, this is the first study presenting high-resolution measurements of regional ventilation in humans breathing normally during hypergravity.
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Affiliation(s)
- M Ax
- Department of Anesthesiology and Intensive Care, Karolinska University Hospital Solna, 171 76 Stockholm, Sweden; Department of Physiology and Pharmacology, Section of Anesthesiology and Intensive Care Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden.
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Stickland MK, Lindinger MI, Olfert IM, Heigenhauser GJF, Hopkins SR. Pulmonary gas exchange and acid-base balance during exercise. Compr Physiol 2013; 3:693-739. [PMID: 23720327 PMCID: PMC8315793 DOI: 10.1002/cphy.c110048] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
As the first step in the oxygen-transport chain, the lung has a critical task: optimizing the exchange of respiratory gases to maintain delivery of oxygen and the elimination of carbon dioxide. In healthy subjects, gas exchange, as evaluated by the alveolar-to-arterial PO2 difference (A-aDO2), worsens with incremental exercise, and typically reaches an A-aDO2 of approximately 25 mmHg at peak exercise. While there is great individual variability, A-aDO2 is generally largest at peak exercise in subjects with the highest peak oxygen consumption. Inert gas data has shown that the increase in A-aDO2 is explained by decreased ventilation-perfusion matching, and the development of a diffusion limitation for oxygen. Gas exchange data does not indicate the presence of right-to-left intrapulmonary shunt developing with exercise, despite recent data suggesting that large-diameter arteriovenous shunt vessels may be recruited with exercise. At the same time, multisystem mechanisms regulate systemic acid-base balance in integrative processes that involve gas exchange between tissues and the environment and simultaneous net changes in the concentrations of strong and weak ions within, and transfer between, extracellular and intracellular fluids. The physicochemical approach to acid-base balance is used to understand the contributions from independent acid-base variables to measured acid-base disturbances within contracting skeletal muscle, erythrocytes and noncontracting tissues. In muscle, the magnitude of the disturbance is proportional to the concentrations of dissociated weak acids, the rate at which acid equivalents (strong acid) accumulate and the rate at which strong base cations are added to or removed from muscle.
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Affiliation(s)
- Michael K. Stickland
- Division of Pulmonary Medicine, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Michael I. Lindinger
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
| | - I. Mark Olfert
- Robert C. Byrd Health Sciences Center, Center for Cardiovascular and Respiratory Sciences, Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, West Virginia
| | | | - Susan R. Hopkins
- Departments of Medicine and Radiology, University of California, San Diego, San Diego, California
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Vogt B, Pulletz S, Elke G, Zhao Z, Zabel P, Weiler N, Frerichs I. Spatial and temporal heterogeneity of regional lung ventilation determined by electrical impedance tomography during pulmonary function testing. J Appl Physiol (1985) 2012; 113:1154-61. [PMID: 22898553 DOI: 10.1152/japplphysiol.01630.2011] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electrical impedance tomography (EIT) is a functional imaging modality capable of tracing continuously regional pulmonary gas volume changes. The aim of our study was to determine if EIT was able to assess spatial and temporal heterogeneity of ventilation during pulmonary function testing in 14 young (37 ± 10 yr, mean age ± SD) and 12 elderly (71 ± 9 yr) subjects without lung disease and in 33 patients with chronic obstructive pulmonary disease (71 ± 9 yr). EIT and spirometry examinations were performed during tidal breathing and a forced vital capacity (FVC) maneuver preceded by full inspiration to total lung capacity. Regional inspiratory vital capacity (IVC); FVC; forced expiratory volume in 1 s (FEV(1)); FEV(1)/FVC; times required to expire 25%, 50%, 75%, and 90% of FVC (t(25), t(50), t(75), t(90)); and tidal volume (V(T)) were determined in 912 EIT image pixels in the chest cross section. Coefficients of variation (CV) were calculated from all pixel values of IVC, FVC, FEV(1), and V(T) to characterize the ventilation heterogeneity. The highest values were found in patients, and no differences existed between the healthy young and elderly subjects. Receiver-operating characteristics curves showed that CV of regional IVC, FVC, FEV(1), and V(T) discriminated the young and elderly subjects from the patients. Frequency distributions of pixel FEV(1)/FVC, t(25), t(50), t(75), and t(90) identified the highest ventilation heterogeneity in patients but distinguished also the healthy young from the elderly subjects. These results indicate that EIT may provide additional information during pulmonary function testing and identify pathologic and age-related spatial and temporal heterogeneity of regional lung function.
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Affiliation(s)
- Barbara Vogt
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Arnold-Heller-Strasse 3, Kiel, Germany
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HEDENSTIERNA G. Oxygen and anesthesia: what lung do we deliver to the post-operative ward? Acta Anaesthesiol Scand 2012; 56:675-85. [PMID: 22471648 DOI: 10.1111/j.1399-6576.2012.02689.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2012] [Indexed: 01/16/2023]
Abstract
Anesthesia is safe in most patients. However, anesthetics reduce functional residual capacity (FRC) and promote airway closure. Oxygen is breathed during the induction of anesthesia, and increased concentration of oxygen (O(2) ) is given during the surgery to reduce the risk of hypoxemia. However, oxygen is rapidly adsorbed behind closed airways, causing lung collapse (atelectasis) and shunt. Atelectasis may be a locus for infection and may cause pneumonia. Measures to prevent atelectasis and possibly reduce post-operative pulmonary complications are based on moderate use of oxygen and preservation or restoration of FRC. Pre-oxygenation with 100% O(2) causes atelectasis and should be followed by a recruitment maneuver (inflation to an airway pressure of 40 cm H(2) O for 10 s and to higher airway pressures in patients with reduced abdominal compliance (obese and patients with abdominal disorders). Pre-oxygenation with 80% O(2) may be sufficient in most patients with no anticipated difficulty in managing the airway, but time to hypoxemia during apnea decreases from mean 7 to 5 min. An alternative, possibly challenging, procedure is induction of anesthesia with continuous positive airway pressure/positive end-expiratory pressure to prevent fall in FRC enabling use of 100% O(2) . A continuous PEEP of 7-10 cm H(2) O may not necessarily improve oxygenation but should keep the lung open until the end of anesthesia. Inspired oxygen concentration of 30-40%, or even less, should suffice if the lung is kept open. The goal of the anesthetic regime should be to deliver a patient with no atelectasis to the post-operative ward and to keep the lung open.
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Affiliation(s)
- G. HEDENSTIERNA
- Department of Medical Sciences; Clinical Physiology; University Hospital; Uppsala; Sweden
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Güney AI, Javadova D, Kırac D, Ulucan K, Koc G, Ergec D, Tavukcu H, Tarcan T. Detection of Y chromosome microdeletions and mitochondrial DNA mutations in male infertility patients. GENETICS AND MOLECULAR RESEARCH 2012; 11:1039-48. [PMID: 22614272 DOI: 10.4238/2012.april.27.2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Infertility affects about 10-15% of all couples attempting pregnancy with infertility attributed to the male partner in approximately half of the cases. Proposed causes of male infertility include sperm motility disturbances, Y chromosome microdeletions, chromosomal abnormalities, single gene mutations, and sperm mitochondrial DNA (mtDNA) rearrangements. To investigate the etiology of decreased sperm fertility and motility of sperm and to develop an appropriate therapeutic strategy, the molecular basis of these defects must be elucidated. In this study, we aimed to reveal the relationships between the genetic factors including sperm mtDNA mutations, Y chromosome microdeletions, and sperm parameters that can be regarded as candidate factors for male infertility. Thirty men with a history of infertility and 30 fertile men were recruited to the study. Y chromosome microdeletions were analyzed by multiplex PCR. Mitochondrial genes ATPase6, Cytb, and ND1, were amplified by PCR and then analyzed by direct sequencing. No Y chromosome microdeletions were detected in either group. However, a total of 38 different nucleotide substitutions were identified in the examined mitochondrial genes in both groups, all of which are statistically non-significant. Fifteen substitutions caused an amino acid change and 12 were considered novel mutations. As a conclusion, mtDNA mutations and Y chromosome microdeletions in male infertility should be examined in larger numbers in order to clarify the effect of genetic factors.
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Affiliation(s)
- A I Güney
- Department of Medical Genetics, Faculty of Medicine, Marmara University, Istanbul, Turkey.
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Vaz Fragoso CA, Gill TM. Respiratory impairment and the aging lung: a novel paradigm for assessing pulmonary function. J Gerontol A Biol Sci Med Sci 2012; 67:264-75. [PMID: 22138206 PMCID: PMC3297762 DOI: 10.1093/gerona/glr198] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 10/02/2011] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Older persons have an increased risk of developing respiratory impairment because the aging lung is likely to have experienced exposures to environmental toxins as well as reductions in physiological capacity. METHODS Systematic review of risk factors and measures of pulmonary function that are most often considered when defining respiratory impairment in aging populations. RESULTS Across the adult life span, there are frequent exposures to environmental toxins, including tobacco smoke, respiratory infections, air pollution, and occupational dusts. Concurrently, there are reductions in physiological capacity that may adversely affect ventilatory control, respiratory muscle strength, respiratory mechanics, and gas exchange. Recent work has provided a strong rationale for defining respiratory impairment as an age-adjusted reduction in spirometric measures of pulmonary function that are independently associated with adverse health outcomes. Specifically, establishing respiratory impairment based on spirometric Z-scores has been shown to be strongly associated with respiratory symptoms, frailty, and mortality. Alternatively, respiratory impairment may be defined by the peak expiratory flow, as measured by a peak flow meter. The peak expiratory flow, when expressed as a Z-score, has been shown to be strongly associated with disability and mortality. However, because it has a reduced diagnostic accuracy, peak expiratory flow should only define respiratory impairment when spirometry is not readily available or an older person cannot adequately perform spirometry. CONCLUSIONS Aging is associated with an increased risk of developing respiratory impairment, which is best defined by spirometric Z-scores. Alternatively, in selected cases, respiratory impairment may be defined by peak expiratory flow, also expressed as a Z-score.
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Affiliation(s)
- Carlos A Vaz Fragoso
- Department of Internal Medicine, Veterans Affairs Clinical Epidemiology Research Center, West Haven, Connecticut 06516, USA.
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Lemyze M, Favory R, Alves I, Perez T, Mathieu D. Manual compression of the abdomen to assess expiratory flow limitation during mechanical ventilation. J Crit Care 2012; 27:37-44. [DOI: 10.1016/j.jcrc.2011.05.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 03/22/2011] [Accepted: 05/07/2011] [Indexed: 01/01/2023]
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Abstract
Major advances in respiratory mechanics occurred primarily in the latter half of the 20th century, and this is when much of our current understanding was secured. The earliest and ancient investigations involving respiratory physiology and mechanics were frequently done in conjunction with other scientific activities and often lacked the ability to make quantitative measurements. This situation changed rapidly in the 20th century, and this relatively recent history of lung mechanics has been greatly influenced by critical technological advances and applications, which have made quantitative experimental testing of ideas possible. From the spirometer of Hutchinson, to the pneumotachograph of Fleisch, to the measurement of esophageal pressure, to the use of the Wilhelmy balance by Clements, and to the unassuming strain gauges for measuring pressure and rapid paper and electronic chart recorders, these enabling devices have generated numerous quantitative experimental studies with greatly increased physiologic understanding and validation of mechanistic theories of lung function in health and disease.
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Affiliation(s)
- Wayne Mitzner
- The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
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Muradyan I, Loring SH, Ferrigno M, Lindholm P, Topulos GP, Patz S, Butler JP. Inhalation heterogeneity from subresidual volumes in elite divers. J Appl Physiol (1985) 2010; 109:1969-73. [PMID: 20864566 DOI: 10.1152/japplphysiol.00953.2009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Punctate reopening of the lung from subresidual volumes (sub-RV) is commonly observed in excised lung preparations, either degassed or collapsed to zero transpulmonary pressure, and in the course of reinflation of human lungs when the chest is open, secondary to traumatic or surgical pneumothoraxes. In the course of physiological studies on two elite breath-hold divers, who are able to achieve lung volumes well below traditional RV with glossopharyngeal exsufflation, we used MRI lung imaging with inhaled hyperpolarized (129)Xe to visualize ventilatory patterns. We observed strikingly inhomogeneous inhalation patterns with small inhalation volumes from sub-RV, consistent with reopening of frankly closed airways. On the other hand, two age-matched and two older controls, inhaling from just above RV, showed a much more homogeneous pattern. Our results demonstrate the concept of frank airway closure below RV in young healthy adults with an intact chest wall.
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Affiliation(s)
- Iga Muradyan
- Department of Radiology, Brigham and Women's Hospital, LMRC, 221 Longwood Ave., Boston, MA 02115, USA.
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Gordon S, Jones A, Sealey R, Buettner P. Body position and cardio-respiratory variables in older people. Arch Gerontol Geriatr 2009; 52:23-7. [PMID: 19948363 DOI: 10.1016/j.archger.2009.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 11/01/2009] [Accepted: 11/04/2009] [Indexed: 11/28/2022]
Abstract
What effect does body position have on cardio-respiratory variables in active older people? An experimental laboratory study was undertaken measuring heart rate, systolic and diastolic blood pressure and oxygen saturation when 26 active people aged 60 years and over adopted five standardized body positions. Measurements were taken every 2 min over a 10-min period in sitting, right side lying, left side lying, supine and supine with the head 20° below the level of the body. Rate pressure product and mean arterial pressure were calculated. Smoking history, medication use, health conditions and activity level were recorded. Height, weight and body fat were measured. Left and right side lying produced significantly lower diastolic and systolic blood pressure, rate pressure product and mean arterial pressure than supine with the head down. Excluding oxygen saturation mean values for all variables remained within recommended normal limits in all positions. Significant differences in cardio-respiratory variables occur when active older people change body position. Positioning as a treatment intervention appears safe in supine, side lying and sitting for this population. Head down supine position should be adopted with caution.
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Affiliation(s)
- Susan Gordon
- School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University, Townsville 4810, Australia.
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Upright position mechanical ventilation: an alternative strategy for ALI/ARDS patients? Med Hypotheses 2009; 73:821-3. [PMID: 19683402 DOI: 10.1016/j.mehy.2009.03.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Revised: 03/17/2009] [Accepted: 03/21/2009] [Indexed: 11/23/2022]
Abstract
Use of body positioning to improve oxygenation in mechanically ventilated patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) has been well documented. However, neither prone position ventilation nor side lying ventilation has been reported to improve the survival. Whether there is a body position superior to routine supine position or other positions as therapeutic adjunct for ventilated patients with ALI and ARDS? We propose the hypothesis that upright position ventilation may be helpful to improve oxygenation and benefit patients with ALI/ARDS. According to the existing physiologic and pathophysiologic data of upright position investigation, we suppose that improvement of V/Q matching, increased functional residual capacity, alveolar recruitment, accelerated diaphragm recovery, early gastric emptying and enteric feeding may be a potential protect mechanism of upright position ventilation. Whether this can be translated into improvement in patient outcome should be further tested in clinical trial.
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Arborelius M, Lilja B. Haemodynamic Changes at Different Lung Volumes. Scandinavian Journal of Clinical and Laboratory Investigation 2009; 29:359-69. [DOI: 10.3109/00365517209080252] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Can new pulmonary gas exchange parameters contribute to evaluation of pulmonary congestion in left-sided heart failure? Can J Cardiol 2009; 25:149-55. [PMID: 19279982 DOI: 10.1016/s0828-282x(09)70042-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND Assessment of pulmonary congestion in left-sided heart failure is necessary for guiding anticongestive therapy. Clinical examination and chest x-ray are semiquantitative methods with poor diagnostic accuracy and reproducibility. OBJECTIVES To establish reference values, describe reproducibility, and investigate the diagnostic and monitoring properties in relation to pulmonary congestion of new pulmonary gas exchange parameters describing ventilation/perfusion mismatch (variable fraction of ventilation [fA2] or the drop in oxygen pressure from the mixed alveolar air of the two ventilated compartments to the nonshunted end-capillary blood [DeltaPO(2)]) and pulmonary shunt. METHODS Sixty healthy volunteers and 69 patients requiring an acute chest x-ray in a cardiac care unit were included. The gas exchange parameters were estimated by analyzing standard bedside respiratory and circulatory measurements obtained during short-term exposure to different levels of inspired oxygen. Nine patients were classified as having pulmonary congestion using a reference diagnosis and were followed during 30 days of anticongestive therapy. Diagnostic and monitoring properties were compared with chest x-ray, N-terminal probrain natriuretic peptide (NT-proBNP), spirometry values, arterial oxygen tension, alveolar-arterial oxygen difference and venous admixture. RESULTS The 95% reference intervals for healthy subjects were narrow (ie, fA2 [0.75 to 0.90], DeltaPO(2) [0.0 kPa to 0.5 kPa] and pulmonary shunt [0.0% to 8.2%]). Reproducibility was relatively good with small within subject coefficients of variation (ie, fA2 [0.05], DeltaPO(2) [0.4 kPa] and pulmonary shunt [2.0%]). fA2, DeltaPO(2) and NT-proBNP had significantly better diagnostic properties, with high sensitivities (100%) but low specificities (30% to 40%). During successful anticongestive therapy, fA2, DeltaPO(2), NT-proBNP and spirometry values showed significant improvements. CONCLUSIONS The gas exchange parameter for ventilation/perfusion mismatch but not pulmonary shunt can have a possible role in rejecting the diagnosis of pulmonary congestion and in monitoring anticongestive therapy.
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