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Bluth T, Serpa Neto A, Schultz MJ, Pelosi P, Gama de Abreu M, Bluth T, Bobek I, Canet JC, Cinnella G, de Baerdemaeker L, Gama de Abreu M, Gregoretti C, Hedenstierna G, Hemmes SNT, Hiesmayr M, Hollmann MW, Jaber S, Laffey J, Licker MJ, Markstaller K, Matot I, Mills GH, Mulier JP, Pelosi P, Putensen C, Rossaint R, Schmitt J, Schultz MJ, Senturk M, Serpa Neto A, Severgnini P, Sprung J, Vidal Melo MF, Wrigge H. Effect of Intraoperative High Positive End-Expiratory Pressure (PEEP) With Recruitment Maneuvers vs Low PEEP on Postoperative Pulmonary Complications in Obese Patients: A Randomized Clinical Trial. JAMA 2019; 321:2292-2305. [PMID: 31157366 PMCID: PMC6582260 DOI: 10.1001/jama.2019.7505] [Citation(s) in RCA: 178] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
IMPORTANCE An intraoperative higher level of positive end-expiratory positive pressure (PEEP) with alveolar recruitment maneuvers improves respiratory function in obese patients undergoing surgery, but the effect on clinical outcomes is uncertain. OBJECTIVE To determine whether a higher level of PEEP with alveolar recruitment maneuvers decreases postoperative pulmonary complications in obese patients undergoing surgery compared with a lower level of PEEP. DESIGN, SETTING, AND PARTICIPANTS Randomized clinical trial of 2013 adults with body mass indices of 35 or greater and substantial risk for postoperative pulmonary complications who were undergoing noncardiac, nonneurological surgery under general anesthesia. The trial was conducted at 77 sites in 23 countries from July 2014-February 2018; final follow-up: May 2018. INTERVENTIONS Patients were randomized to the high level of PEEP group (n = 989), consisting of a PEEP level of 12 cm H2O with alveolar recruitment maneuvers (a stepwise increase of tidal volume and eventually PEEP) or to the low level of PEEP group (n = 987), consisting of a PEEP level of 4 cm H2O. All patients received volume-controlled ventilation with a tidal volume of 7 mL/kg of predicted body weight. MAIN OUTCOMES AND MEASURES The primary outcome was a composite of pulmonary complications within the first 5 postoperative days, including respiratory failure, acute respiratory distress syndrome, bronchospasm, new pulmonary infiltrates, pulmonary infection, aspiration pneumonitis, pleural effusion, atelectasis, cardiopulmonary edema, and pneumothorax. Among the 9 prespecified secondary outcomes, 3 were intraoperative complications, including hypoxemia (oxygen desaturation with Spo2 ≤92% for >1 minute). RESULTS Among 2013 adults who were randomized, 1976 (98.2%) completed the trial (mean age, 48.8 years; 1381 [69.9%] women; 1778 [90.1%] underwent abdominal operations). In the intention-to-treat analysis, the primary outcome occurred in 211 of 989 patients (21.3%) in the high level of PEEP group compared with 233 of 987 patients (23.6%) in the low level of PEEP group (difference, -2.3% [95% CI, -5.9% to 1.4%]; risk ratio, 0.93 [95% CI, 0.83 to 1.04]; P = .23). Among the 9 prespecified secondary outcomes, 6 were not significantly different between the high and low level of PEEP groups, and 3 were significantly different, including fewer patients with hypoxemia (5.0% in the high level of PEEP group vs 13.6% in the low level of PEEP group; difference, -8.6% [95% CI, -11.1% to 6.1%]; P < .001). CONCLUSIONS AND RELEVANCE Among obese patients undergoing surgery under general anesthesia, an intraoperative mechanical ventilation strategy with a higher level of PEEP and alveolar recruitment maneuvers, compared with a strategy with a lower level of PEEP, did not reduce postoperative pulmonary complications. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT02148692.
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Affiliation(s)
| | - Thomas Bluth
- Department of Anesthesiology and Critical Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
| | - Ary Serpa Neto
- Department of Critical Care Medicine, Hospital Israelita Albert Einstein, Sao Paulo, Brazil
| | - Marcus J Schultz
- Department of Intensive Care, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Policlinico San Martino, Genoa, Italy
| | - Marcelo Gama de Abreu
- Department of Anesthesiology and Critical Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany
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Cortegiani A, Gregoretti C, Neto AS, Hemmes SNT, Ball L, Canet J, Hiesmayr M, Hollmann MW, Mills GH, Melo MFV, Putensen C, Schmid W, Severgnini P, Wrigge H, Gama de Abreu M, Schultz MJ, Pelosi P. Association between night-time surgery and occurrence of intraoperative adverse events and postoperative pulmonary complications. Br J Anaesth 2019; 122:361-369. [PMID: 30770054 DOI: 10.1016/j.bja.2018.10.063] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/21/2018] [Accepted: 10/28/2018] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND The aim of this post hoc analysis of a large cohort study was to evaluate the association between night-time surgery and the occurrence of intraoperative adverse events (AEs) and postoperative pulmonary complications (PPCs). METHODS LAS VEGAS (Local Assessment of Ventilatory Management During General Anesthesia for Surgery) was a prospective international 1-week study that enrolled adult patients undergoing surgical procedures with general anaesthesia and mechanical ventilation in 146 hospitals across 29 countries. Surgeries were defined as occurring during 'daytime' when induction of anaesthesia was between 8:00 AM and 7:59 PM, and as 'night-time' when induction was between 8:00 PM and 7:59 AM. RESULTS Of 9861 included patients, 555 (5.6%) underwent surgery during night-time. The proportion of patients who developed intraoperative AEs was higher during night-time surgery in unmatched (43.6% vs 34.1%; P<0.001) and propensity-matched analyses (43.7% vs 36.8%; P=0.029). PPCs also occurred more often in patients who underwent night-time surgery (14% vs 10%; P=0.004) in an unmatched cohort analysis, although not in a propensity-matched analysis (13.8% vs 11.8%; P=0.39). In a multivariable regression model, including patient characteristics and types of surgery and anaesthesia, night-time surgery was independently associated with a higher incidence of intraoperative AEs (odds ratio: 1.44; 95% confidence interval: 1.09-1.90; P=0.01), but not with a higher incidence of PPCs (odds ratio: 1.32; 95% confidence interval: 0.89-1.90; P=0.15). CONCLUSIONS Intraoperative adverse events and postoperative pulmonary complications occurred more often in patients undergoing night-time surgery. Imbalances in patients' clinical characteristics, types of surgery, and intraoperative management at night-time partially explained the higher incidence of postoperative pulmonary complications, but not the higher incidence of adverse events. CLINICAL TRIAL REGISTRATION NCT01601223.
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Affiliation(s)
- A Cortegiani
- Department of Surgical, Oncological and Oral Science, Section of Anesthesia, Analgesia, Intensive Care and Emergency, Policlinico Paolo Giaccone, University of Palermo, Palermo, Italy.
| | - C Gregoretti
- Department of Surgical, Oncological and Oral Science, Section of Anesthesia, Analgesia, Intensive Care and Emergency, Policlinico Paolo Giaccone, University of Palermo, Palermo, Italy
| | - A S Neto
- Department of Intensive Care and Laboratory of Experimental Intensive Care and Anesthesia, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Department of Critical Care Medicine, Hospital Israelita Albert Einstein, São Paulo, Brazil
| | - S N T Hemmes
- Department of Intensive Care and Laboratory of Experimental Intensive Care and Anesthesia, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Department of Anaesthesiology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - L Ball
- Dipartimento di Scienze Chirurgiche e Diagnostiche Integrate, Università degli Studi di Genova, Genova, Italy; IRCCS Ospedale Policlinico San Martino, Genova, Italy
| | - J Canet
- Department of Anesthesiology and Postoperative Care, Hospital Universitari Germans Trias i Pujol, Barcelona, Spain
| | - M Hiesmayr
- Division of Cardiac, Thoracic, Vascular Anesthesia and Intensive Care, Medical University of Vienna, Vienna, Austria
| | - M W Hollmann
- Department of Anaesthesiology, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - G H Mills
- Operating Services, Critical Care and Anesthesia, Sheffield Teaching Hospitals, Sheffield and University of Sheffield, Sheffield, UK
| | - M F V Melo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - C Putensen
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Bonn, Bonn, Germany
| | - W Schmid
- Division of Cardiac, Thoracic, Vascular Anesthesia and Intensive Care, Medical University of Vienna, Vienna, Austria
| | - P Severgnini
- Department of Biotechnology and Sciences of Life, ASST Sette Laghi Ospedale di Circolo e Fondazione Macchi, University of Insubria, Varese, Italy
| | - H Wrigge
- Department of Anesthesiology and Intensive Care Medicine, University of Leipzig, Leipzig, Germany
| | - M Gama de Abreu
- Department of Anaesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - M J Schultz
- Department of Intensive Care and Laboratory of Experimental Intensive Care and Anesthesia, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands; Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - P Pelosi
- Dipartimento di Scienze Chirurgiche e Diagnostiche Integrate, Università degli Studi di Genova, Genova, Italy; IRCCS Ospedale Policlinico San Martino, Genova, Italy
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Staehr-Rye AK, Meyhoff CS, Scheffenbichler FT, Vidal Melo MF, Gätke MR, Walsh JL, Ladha KS, Grabitz SD, Nikolov MI, Kurth T, Rasmussen LS, Eikermann M. High intraoperative inspiratory oxygen fraction and risk of major respiratory complications. Br J Anaesth 2018; 119:140-149. [PMID: 28974067 DOI: 10.1093/bja/aex128] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2017] [Indexed: 11/14/2022] Open
Abstract
Background High inspiratory oxygen fraction ( FIO2 ) may improve tissue oxygenation but also impair pulmonary function. We aimed to assess whether the use of high intraoperative FIO2 increases the risk of major respiratory complications. Methods We studied patients undergoing non-cardiothoracic surgery involving mechanical ventilation in this hospital-based registry study. The cases were divided into five groups based on the median FIO2 between intubation and extubation. The primary outcome was a composite of major respiratory complications (re-intubation, respiratory failure, pulmonary oedema, and pneumonia) developed within 7 days after surgery. Secondary outcomes included 30-day mortality. Several predefined covariates were included in a multivariate logistic regression model. Results The primary analysis included 73 922 cases, of whom 3035 (4.1%) developed a major respiratory complication within 7 days of surgery. For patients in the high- and low-oxygen groups, the median FIO2 was 0.79 [range 0.64-1.00] and 0.31 [0.16-0.34], respectively. Multivariate logistic regression analysis revealed that the median FIO2 was associated in a dose-dependent manner with increased risk of respiratory complications (adjusted odds ratio for high vs low FIO2 1.99, 95% confidence interval [1.72-2.31], P -value for trend <0.001). This finding was robust in a series of sensitivity analyses including adjustment for intraoperative oxygenation. High median FIO2 was also associated with 30-day mortality (odds ratio for high vs low FIO2 1.97, 95% confidence interval [1.30-2.99], P -value for trend <0.001). Conclusions In this analysis of administrative data on file, high intraoperative FIO2 was associated in a dose-dependent manner with major respiratory complications and with 30-day mortality. The effect remained stable in a sensitivity analysis controlled for oxygenation. Clinical trial registration NCT02399878.
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Affiliation(s)
- A K Staehr-Rye
- Department of Anaesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA.,Department of Anaesthesiology, Herlev and Gentofte Hospital, University of Copenhagen, Herlev Ringvej 75, 2730 Herlev, Denmark
| | - C S Meyhoff
- Department of Anaesthesiology, Herlev and Gentofte Hospital, University of Copenhagen, Herlev Ringvej 75, 2730 Herlev, Denmark.,Department of Anaesthesia and Intensive Care, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Denmark
| | - F T Scheffenbichler
- Department of Anaesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - M F Vidal Melo
- Department of Anaesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - M R Gätke
- Department of Anaesthesiology, Herlev and Gentofte Hospital, University of Copenhagen, Herlev Ringvej 75, 2730 Herlev, Denmark
| | - J L Walsh
- Department of Anaesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - K S Ladha
- Department of Anaesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - S D Grabitz
- Department of Anaesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - M I Nikolov
- Department of Anaesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - T Kurth
- Institute of Public Health, Charité Universitätzmedizin Berlin, Germany
| | - L S Rasmussen
- Department of Anaesthesia, Centre of Head and Orthopaedics, Rigshospitalet, University of Copenhagen, Denmark
| | - M Eikermann
- Department of Anaesthesia, Critical Care, Pain Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA.,Klinik für Anaesthesie und Intensivmedizin, Universitaetsklinikum Essen, Essen, Germany
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Fernandez-Bustamante A, Vidal Melo MF. Bedside assessment of lung aeration and stretch. Br J Anaesth 2018; 121:1001-1004. [PMID: 30336843 PMCID: PMC8604375 DOI: 10.1016/j.bja.2018.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/06/2018] [Accepted: 08/09/2018] [Indexed: 11/18/2022] Open
Affiliation(s)
- A Fernandez-Bustamante
- Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO, USA; Webb Waring Center, University of Colorado School of Medicine, Aurora, CO, USA
| | - M F Vidal Melo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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Bagchi A, Rudolph MI, Ng PY, Timm FP, Long DR, Shaefi S, Ladha K, Vidal Melo MF, Eikermann M. The association of postoperative pulmonary complications in 109,360 patients with pressure-controlled or volume-controlled ventilation. Anaesthesia 2017; 72:1334-1343. [PMID: 28891046 DOI: 10.1111/anae.14039] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/03/2017] [Indexed: 12/20/2022]
Abstract
We thought that the rate of postoperative pulmonary complications might be higher after pressure-controlled ventilation than after volume-controlled ventilation. We analysed peri-operative data recorded for 109,360 adults, whose lungs were mechanically ventilated during surgery at three hospitals in Massachusetts, USA. We used multivariable regression and propensity score matching. Postoperative pulmonary complications were more common after pressure-controlled ventilation, odds ratio (95%CI) 1.29 (1.21-1.37), p < 0.001. Tidal volumes and driving pressures were more varied with pressure-controlled ventilation compared with volume-controlled ventilation: mean (SD) variance from the median 1.61 (1.36) ml.kg-1 vs. 1.23 (1.11) ml.kg-1 , p < 0.001; and 3.91 (3.47) cmH2 O vs. 3.40 (2.69) cmH2 O, p < 0.001. The odds ratio (95%CI) of pulmonary complications after pressure-controlled ventilation compared with volume-controlled ventilation at positive end-expiratory pressures < 5 cmH2 O was 1.40 (1.26-1.55) and 1.20 (1.11-1.31) when ≥ 5 cmH2 O, both p < 0.001, a relative risk ratio of 1.17 (1.03-1.33), p = 0.023. The odds ratio (95%CI) of pulmonary complications after pressure-controlled ventilation compared with volume-controlled ventilation at driving pressures of < 19 cmH2 O was 1.37 (1.27-1.48), p < 0.001, and 1.16 (1.04-1.30) when ≥ 19 cmH2 O, p = 0.011, a relative risk ratio of 1.18 (1.07-1.30), p = 0.016. Our data support volume-controlled ventilation during surgery, particularly for patients more likely to suffer postoperative pulmonary complications.
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Affiliation(s)
- A Bagchi
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - M I Rudolph
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - P Y Ng
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - F P Timm
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - D R Long
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - S Shaefi
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - K Ladha
- Department of Anesthesia and Pain Medicine, University of Toronto and Toronto General Hospital, Toronto, ON, Canada
| | - M F Vidal Melo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - M Eikermann
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA.,Klinik für Anästhesiologie und Intensivmedizin, Universität Duisburg-Essen, Essen, Germany
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Álvares-Carvalho SV, Silva-Mann R, Gois IB, Melo MFV, Oliveira AS, Ferreira RA, Gomes LJ. Restoration over time and sustainability of Schinus terebinthifolius Raddi. Genet Mol Res 2017; 16:gmr-16-02-gmr.16029669. [PMID: 28613379 DOI: 10.4238/gmr16029669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The success of recovery programs on degraded areas is dependent on the genetic material to be used, which should present heterozygosity and genetic diversity in native and recovered populations. This study was carried out to evaluate the model efficiency to enable the recovery of a degraded area of the Lower São Francisco, Sergipe, Brazil. The target species for this study was Schinus terebinthifolius Raddi. Three populations were analyzed, the recovered area, seed-tree source population, and native tree population border established to the recovered area. The random amplified polymorphic DNA (RAPD) markers were used for diversity analysis. Genetic structure was estimated to evaluate the level of genetic variability existent in each population. There was no correlation between the spatial distribution and the genetic distances for all trees of the recovered area. The heterozygosity present in the recovered population was higher than the native tree population. The seed-tree source population presents genetic bottlenecks. Three clusters were suggested (ΔK = 3) with non-genetic structure. High intra-population genetic variability and inter-population differentiation are present. However, gene flow may also introduce potentially adaptive alleles in the populations of the recovered area, and the native population is necessary to ensure the sustainability and maintenance of the populations by allelic exchange.
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Affiliation(s)
- S V Álvares-Carvalho
- Programa de Pós-Graduação em Agricultura e Biodiversidade, Laboratório do Grupo de Pesquisa em Conservação, Melhoramento e Gestão de Recursos Genéticos/GENAPLANT, Universidade Federal de Sergipe, São Cristóvão, SE, Brasil
| | - R Silva-Mann
- Laboratório do Grupo de Pesquisa em Conservação, Melhoramento e Gestão de Recursos Genéticos/GENAPLANT, Departamento de Engenharia Agronômica, Universidade Federal de Sergipe, São Cristóvão, SE, Brasil
| | - I B Gois
- Programa de Pós-Graduação em Genética e Melhoramento, Universidade Federal de Viçosa, Viçosa, MG, Brasil
| | - M F V Melo
- Centro de Ciências Agrárias, Universidade Federal de Alagoas, Rio Largo, AL, Brasil
| | | | - R A Ferreira
- Centro de Ciências Agrárias Aplicadas, Departamento de Ciências Florestais, Universidade Federal de Sergipe, São Cristóvão, SE, Brasil
| | - L J Gomes
- Centro de Ciências Agrárias Aplicadas, Departamento de Ciências Florestais, Universidade Federal de Sergipe, São Cristóvão, SE, Brasil
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Melo MFV, Gonçalves LO, Rabbani ARC, Álvares-Carvalho SV, Pinheiro JB, Zucchi MI, Silva-Mann R. Populations of Erythrina velutina Willd. at risk of extinction. Genet Mol Res 2015; 14:10298-307. [PMID: 26345968 DOI: 10.4238/2015.august.28.15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The goal of this study was to characterize the structure of two natural populations of the coral tree using RAPD and ISSR markers. The study evaluated all individuals in two different areas in the northeastern region of Brazil: the first was in the riparian area, 10 km x 100 m along the edge of the lower São Francisco River, and the second was in the municipality of Pinhão, in a semiarid region between the municipalities of Neópolis and Santana do São Francisco. We used all the coral trees present in those two areas (37 individuals). The results of the RAPD and ISSR markers were highly congruent, supporting the reliability of the techniques used. Similarity was estimated using the Jaccard arithmetic complement index. A dendrogram was constructed using the unweighted pair group method with arithmetic mean cluster algorithm, and the robustness of the data was bootstrapped with 5000 replicates. A principal coordinate analysis was performed on the basis of Jaccard coefficients. The total genetic variation observed was 21%, corresponding to the variation between the populations, and 79% of the variation was observed within the populations.
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Affiliation(s)
- M F V Melo
- Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, SP, Brasil
| | - L O Gonçalves
- Secretaria Municipal de Agricultura e Desenvolvimento Econômico, Prefeitura Municipal de Jeremoabo, Jeremoabo, BA, Brasil
| | - A R C Rabbani
- Instituto Federal de Educação, Ciência e Tecnologia da Bahia, Porto Seguro, BA, Brasil
| | - S V Álvares-Carvalho
- Departamento de Engenharia Agronômica, Universidade Federal de Sergipe, São Cristóvão, SE, Brasil
| | - J B Pinheiro
- Departamento de Genética, Escola Superior de Agricultura ''Luiz de Queiroz'', Piracicaba, SP, Brasil
| | - M I Zucchi
- Agência Paulista de Tecnologia dos Agronegócios, Polo Regional de Desenvolvimento Tecnológico do Centro Sul, Piracicaba, SP, Brasil
| | - R Silva-Mann
- Departamento de Engenharia Agronômica, Universidade Federal de Sergipe, São Cristóvão, SE, Brasil
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Tgavalekos NT, Musch G, Harris RS, Vidal Melo MF, Winkler T, Schroeder T, Callahan R, Lutchen KR, Venegas JG. Relationship between airway narrowing, patchy ventilation and lung mechanics in asthmatics. Eur Respir J 2007; 29:1174-81. [PMID: 17360726 DOI: 10.1183/09031936.00113606] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Bronchoconstriction in asthma results in patchy ventilation forming ventilation defects (VDefs). Patchy ventilation is clinically important because it affects obstructive symptoms and impairs both gas exchange and the distribution of inhaled medications. The current study combined functional imaging, oscillatory mechanics and theoretical modelling to test whether the degrees of constriction of airways feeding those units outside VDefs were related to the extent of VDefs in bronchoconstricted asthmatic subjects. Positron emission tomography was used to quantify the regional distribution of ventilation and oscillatory mechanics were measured in asthmatic subjects before and after bronchoconstriction. For each subject, ventilation data was mapped into an anatomically based lung model that was used to evaluate whether airway constriction patterns, consistent with the imaging data, were capable of matching the measured changes in airflow obstruction. The degree and heterogeneity of constriction of the airways feeding alveolar units outside VDefs was similar among the subjects studied despite large inter-subject variability in airflow obstruction and the extent of the ventilation defects. Analysis of the data amongst the subjects showed an inverse relationship between the reduction in mean airway conductance, measured in the breathing frequency range during bronchoconstriction, and the fraction of lung involved in ventilation defects. The current data supports the concept that patchy ventilation is an expression of the integrated system and not just the sum of independent responses of individual airways.
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Affiliation(s)
- N T Tgavalekos
- Department of Anesthesia and Critical Care (CLN-237F), Massachusetts General Hospital, and Department of Biomedical Engineering, Boston University, Boston 02114, USA
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Vidal Melo MF, Barazanji K, Winga E, Johnson RL. Estimate of pulmonary diffusing capacity for oxygen during exercise in humans from routine O2 and CO2 measurements. Clin Physiol Funct Imaging 2004; 24:46-57. [PMID: 14717748 DOI: 10.1046/j.1475-0961.2003.00528.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A method to estimate pulmonary diffusing capacity for O(2) (D(LO2)) during exercise based on routine O(2) and CO(2) transport variables is presented. It is based on the fitting of a mathematical model to gas exchange data. The model includes heterogeneity (described as two exchanging compartments), diffusion limitation and right-to-left shunt. Mass conservation equations and Bohr integration were solved to calculate partial pressures in each compartment. Diffusion was distributed with perfusion. Two-compartment ventilation and perfusion distributions were estimated at rest during conditions of negligible diffusion limitation. These distributions were used during hypoxic and normoxic exercise to obtain the D(LO2) from the model computations (D(LO2)2C) compatible with experimental data. Three normals, four sarcoid patients and four patients after lung resection were studied. An independent technique for carbon monoxide was used to provide experimental estimates of DLo2 (D(LO2)EXP, rebreathing technique for sarcoid patients and single breath for lung resection). D(LO2)2C was highly correlated with D(LO2)EXP (r2 = 0.95, P<0.001) and the slope of the regression line was not statistically different from 1. The mean (D(LO2)EXP - D(LO2)2C) difference was -1.0 +/- 7.4 ml min-1 mmHg-1. The results suggest that use of a refined analytical procedure allows for assessment of D(LO2) from routine O(2) and CO(2) measurements comparable with those obtained from independent carbon monoxide techniques. The method may be an alternative for estimates of D(LO2) during exercise.
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Affiliation(s)
- M F Vidal Melo
- Department of Anesthesia and Critical Care, Massachusetts General Hospital, Boston, MA 02461, USA.
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O'Neill K, Venegas JG, Richter T, Harris RS, Layfield JDH, Musch G, Winkler T, Melo MFV. Modeling kinetics of infused 13NN-saline in acute lung injury. J Appl Physiol (1985) 2003; 95:2471-84. [PMID: 12897030 DOI: 10.1152/japplphysiol.00401.2003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A mathematical model was developed to estimate right-to-left shunt (Fs) and the volume of distribution of 13NN in alveolar gas (VA) and shunt tissue (Vs). The data obtained from this model are complementary to, and obtained simultaneously with, pulmonary functional positron emission tomography (PET). The model describes 13NN kinetics in four compartments: central mixing volume, gas-exchanging lung, shunting compartment, and systemic recirculation. To validate the model, five normal prone (NP) and six surfactant-depleted sheep in the supine (LS) and prone (LP) positions were studied under general anesthesia. A central venous bolus of 13NN-labeled saline was injected at the onset of apnea as PET imaging and arterial 13NN sampling were initiated. The model fit the tracer kinetics well (mean r2 = 0.93). Monte Carlo simulations showed that parameters could be accurately identified in the presence of expected experimental noise. Fs derived from the model correlated well with shunt estimates derived from O2 blood concentrations and from PET images. Fs was higher for LS (54 +/- 18%) than for LP (5 +/- 4%) and NP (1 +/- 1%, P < 0.01). VA, as a fraction of PET-measured lung gas volume, was lower for LS (0.18 +/- 0.09) than for LP (0.96 +/- 0.28, P < 0.01), whereas Vs, as a fraction of PET-measured lung tissue volume, was higher for LS (0.46 +/- 0.26) than for LP (0.05 +/- 0.08, P < 0.01). The main conclusions are as follows: 1) the model accurately describes measured arterial 13NN kinetics and provides estimates of Fs, and 2) in this animal model of acute lung injury, the fraction of available gas volume participating in gas exchange is reduced in the supine position.
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Affiliation(s)
- K O'Neill
- Department of Anesthesia and Critical Care, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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Abstract
We studied the effect of the interaction between diffusion limitation and alveolar ventilation to perfusion ratio (VA/Q) mismatch in the relation between blood gas partial pressures and cardiac output (Q). The analysis was based on a mathematical model of gas exchange involving two exchanging compartments and a right to left shunt. A system of equations describing alveolar-arterial mass conservation for O2, CO2 and N2 and Bohr integration for O2 and CO2 was interactively solved to find sets of alveolar and blood gas partial pressures fitting input data. Simulations used values compatible with patients in respiratory failure and neonate piglets. Association of (VA/Q) mismatch and diffusion impairment limited the increase of PaO2 with Q. A maximum in the PaO2 vs. Q curve can be attained, further Q increases lead to reductions in PaO2. The effect was accentuated by increasing (VA/Q) and diffusion to perfusion heterogeneity. Combination of (VA/Q) mismatch and diffusion limitation was synergistic leading to greater reductions in PaO2 than expected from simple addition of their independent influences. The findings are compatible with experimental data.
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Affiliation(s)
- M F Vidal Melo
- Department of Anesthesia and Critical Care, Massachusetts General Hospital, Boston 02114, USA.
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Vidal Melo MF, Loeppky JA, Caprihan A, Luft UC. Alveolar ventilation to perfusion heterogeneity and diffusion impairment in a mathematical model of gas exchange. Comput Biomed Res 1993; 26:103-20. [PMID: 8477584 DOI: 10.1006/cbmr.1993.1007] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This study describes a two-compartment model of pulmonary gas exchange in which alveolar ventilation to perfusion (VA/Q) heterogeneity and impairment of pulmonary diffusing capacity (D) are simultaneously taken into account. The mathematical model uses as input data measurements usually obtained in the lung function laboratory. It consists of two compartments and an anatomical shunt. Each compartment receives fractions of alveolar ventilation and blood flow. Mass balance equations and integration of Fick's law of diffusion are used to compute alveolar and blood O2 and CO2 values compatible with input O2 uptake and CO2 elimination. Two applications are presented. The first is a method to partition O2 and CO2 alveolar-arterial gradients into VA/Q and D components. The technique is evaluated in data of patients with chronic obstructive pulmonary disease (COPD). The second is a theoretical analysis of the effects of blood flow variation in alveolar and blood O2 partial pressures. The results show the importance of simultaneous consideration of D to estimate VA/Q heterogeneity in patients with diffusion impairment. This factor plays an increasing role in gas alveolar-arterial gradients as severity of COPD increases. Association of VA/Q heterogeneity and D may produce an increase of O2 arterial pressure with decreasing QT which would not be observed if only D were considered. We conclude that the presented computer model is a useful tool for description and interpretation of data from COPD patients and for performing theoretical analysis of variables involved in the gas exchange process.
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Affiliation(s)
- M F Vidal Melo
- Department of Experimental Surgery, University of Heidelberg, Germany
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Vidal Melo MF, Caprihan A, Luft UC, Loeppky JA. Distribution of ventilation and diffusion with perfusion in a two-compartment model of gas exchange. Adv Exp Med Biol 1990; 277:653-64. [PMID: 2128995 DOI: 10.1007/978-1-4684-8181-5_74] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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