RESUMO
Coronavirus disease 2019 (COVID-19) is a disease caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has resulted in a pandemic1. The C5a complement factor and its receptor C5aR1 (also known as CD88) have a key role in the initiation and maintenance of several inflammatory responses by recruiting and activating neutrophils and monocytes1. Here we provide a longitudinal analysis of immune responses, including phenotypic analyses of immune cells and assessments of the soluble factors that are present in the blood and bronchoalveolar lavage fluid of patients at various stages of COVID-19 severity, including those who were paucisymptomatic or had pneumonia or acute respiratory distress syndrome. The levels of soluble C5a were increased in proportion to the severity of COVID-19 and high expression levels of C5aR1 receptors were found in blood and pulmonary myeloid cells, which supports a role for the C5a-C5aR1 axis in the pathophysiology of acute respiratory distress syndrome. Anti-C5aR1 therapeutic monoclonal antibodies prevented the C5a-mediated recruitment and activation of human myeloid cells, and inhibited acute lung injury in human C5aR1 knock-in mice. These results suggest that blockade of the C5a-C5aR1 axis could be used to limit the infiltration of myeloid cells in damaged organs and prevent the excessive lung inflammation and endothelialitis that are associated with acute respiratory distress syndrome in patients with COVID-19.
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COVID-19/complicações , COVID-19/imunologia , Complemento C5a/imunologia , Inflamação/complicações , Inflamação/imunologia , Receptor da Anafilatoxina C5a/imunologia , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/imunologia , Lesão Pulmonar Aguda/prevenção & controle , Animais , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/imunologia , Antígeno CD11b/imunologia , Antígeno CD11b/metabolismo , COVID-19/sangue , COVID-19/patologia , Complemento C5a/antagonistas & inibidores , Complemento C5a/biossíntese , Síndrome da Liberação de Citocina/tratamento farmacológico , Síndrome da Liberação de Citocina/imunologia , Síndrome da Liberação de Citocina/prevenção & controle , Modelos Animais de Doenças , Feminino , Humanos , Inflamação/tratamento farmacológico , Inflamação/patologia , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos C57BL , Células Mieloides/efeitos dos fármacos , Células Mieloides/imunologia , Células Mieloides/patologia , Receptor da Anafilatoxina C5a/antagonistas & inibidores , Receptor da Anafilatoxina C5a/sangue , Síndrome do Desconforto Respiratório/tratamento farmacológico , Síndrome do Desconforto Respiratório/imunologia , Síndrome do Desconforto Respiratório/prevenção & controle , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/imunologia , SARS-CoV-2/patogenicidadeRESUMO
OBJECTIVES: Severe COVID-19 is associated with exaggerated complement activation. We assessed the efficacy and safety of avdoralimab (an anti-C5aR1 mAb) in severe COVID-19. DESIGN: FOR COVID Elimination (FORCE) was a double-blind, placebo-controlled study. SETTING: Twelve clinical sites in France (ICU and general hospitals). PATIENTS: Patients receiving greater than or equal to 5 L oxygen/min to maintain Sp o2 greater than 93% (World Health Organization scale ≥ 5). Patients received conventional oxygen therapy or high-flow oxygen (HFO)/noninvasive ventilation (NIV) in cohort 1; HFO, NIV, or invasive mechanical ventilation (IMV) in cohort 2; and IMV in cohort 3. INTERVENTIONS: Patients were randomly assigned, in a 1:1 ratio, to receive avdoralimab or placebo. The primary outcome was clinical status on the World Health Organization ordinal scale at days 14 and 28 for cohorts 1 and 3, and the number of ventilator-free days at day 28 (VFD28) for cohort 2. MEASUREMENTS AND MAIN RESULTS: We randomized 207 patients: 99 in cohort 1, 49 in cohort 2, and 59 in cohort 3. During hospitalization, 95% of patients received glucocorticoids. Avdoralimab did not improve World Health Organization clinical scale score on days 14 and 28 (between-group difference on day 28 of -0.26 (95% CI, -1.2 to 0.7; p = 0.7) in cohort 1 and -0.28 (95% CI, -1.8 to 1.2; p = 0.6) in cohort 3). Avdoralimab did not improve VFD28 in cohort 2 (between-group difference of -6.3 (95% CI, -13.2 to 0.7; p = 0.96) or secondary outcomes in any cohort. No subgroup of interest was identified. CONCLUSIONS: In this randomized trial in hospitalized patients with severe COVID-19 pneumonia, avdoralimab did not significantly improve clinical status at days 14 and 28 (funded by Innate Pharma, ClinicalTrials.gov number, NCT04371367).
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COVID-19 , Humanos , SARS-CoV-2 , Anticorpos Monoclonais Humanizados/uso terapêutico , Oxigênio , Resultado do TratamentoRESUMO
BACKGROUND: A high number of thrombotic complications have been reported in critically ill patients with coronavirus disease 2019 (COVID-19) and appear to be related to a hypercoagulable state. Evidence regarding detection, management, and monitoring of COVID-19-associated coagulopathy is still missing. We propose to describe the thrombus viscoelastic properties to investigate the mechanisms of hypercoagulability in patients with COVID-19. METHODS: Thromboelastography (TEG) was performed in 24 consecutive patients admitted to a single intensive care unit for COVID-19 pneumonia, and 10 had a second TEG before being discharged alive from the intensive care unit. RESULTS: Compared with a group of 20 healthy participants, patients with COVID-19 had significantly decreased values of reaction time, coagulation time, and lysis index and increased values of α angle, maximum amplitude, clot strength, and coagulation index. Velocity curves were consistent with increased generation of thrombin. These values persisted in surviving patients despite their good clinical course. DISCUSSION: In patients with COVID-19, TEG demonstrates a complex and prolonged hypercoagulable state including fast initiation of coagulation and clot reinforcement, low fibrinolysis, high potential of thrombin generation, and high fibrinogen and platelet contribution. The antithrombotic strategy in patients with COVID-19 during intensive care hospitalisation and after discharge should be investigated in further studies.
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COVID-19/sangue , Pneumonia Viral/sangue , Tromboelastografia , Trombofilia/diagnóstico , Trombofilia/virologia , Idoso , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Pneumonia Viral/virologia , SARS-CoV-2RESUMO
We report 77 cases of occupational exposures for 57 healthcare workers at the Ebola Treatment Center in Conakry, Guinea, during the Ebola virus disease outbreak in 2014-2015. Despite the high incidence of 3.5 occupational exposures/healthcare worker/year, only 18% of workers were at high risk for transmission, and no infections occurred.
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Ebolavirus , Pessoal de Saúde , Doença pelo Vírus Ebola/epidemiologia , Doença pelo Vírus Ebola/transmissão , Exposição Ocupacional/efeitos adversos , Guiné/epidemiologia , Humanos , Incidência , Estudos ProspectivosRESUMO
BACKGROUND: The pathogenesis of Ebola virus disease (EVD) remains unclear. The sporadic nature of Ebola outbreaks and their occurrence in resource-limited settings have precluded the acquisition of extensive clinical and laboratory data. Rhabdomyolysis during EVD has been suggested to occur in previous studies showing increased aspartate aminotransferase-alanine aminotransferase ratios, but, to date, has not been confirmed with creatine kinase (CK) assays. METHODS: We performed an observational study of 38 patients admitted to an Ebola treatment center from January to April 2015. CK values from patients with confirmed EVD were compared with those in patients without confirmed EVD. A panel of other analyses were also performed. In patients with EVD, characteristics were compared between survivors and nonsurvivors. RESULTS: High levels of CK were more frequent in patients with EVD than in those without (P = .002), and rhabdomyolysis was more frequent (59% vs 19%, respectively; P = .03). CK levels >5000 U/L were observed in 36% of patients with EVD. Also in patients with EVD, fatal outcome was significantly associated with higher creatinine and bilirubin levels, international normalized ratio, and viral load. CONCLUSIONS: Rhabdomyolysis is a frequent disorder in EVD and seems to be more common than in other viral infections. It may contribute to the renal failure observed in nonsurviving patients. More studies are needed to determine the impact of rhabdomyolysis on EVD outcome.
Assuntos
Doença pelo Vírus Ebola/complicações , Doença pelo Vírus Ebola/epidemiologia , Rabdomiólise/epidemiologia , Rabdomiólise/etiologia , Adulto , Creatina Quinase/sangue , Feminino , Guiné/epidemiologia , Humanos , Masculino , Mialgia , Insuficiência Renal , Adulto JovemRESUMO
OBJECTIVE: Chest trauma remains a leading cause of trauma-death. Since lung contusion is one of the most important lesions implicated, the aim of this experimental study was to evaluate the cardiorespiratory consequences of an isolated lung contusion model. METHODS: Twenty-eight anesthetized pigs were studied during four hours. We induced a right lung contusion with five bolt shots (70 joules each) using a 22-caliber charge in twenty of them. Eight others pigs constituted the control group. The trauma consequences were assessed by histology, measurements of arterial oxygenation, plasma cytokines, pressure-volume mechanics, hemodynamic monitoring using the PiCCO system and a pulmonary artery catheter. The extra-vascular lung water was measured using the gravimetric method. RESULTS: Histology confirmed an isolated right lung contusion without cardiac injury. Compared to baseline values, the trauma group was characterized by a decrease in cardiac index (3.3 ± 0.8 vs 3.9 ± 1.2 l/min/m(2); P < .05) and mean arterial pressure (80 ± 21 vs 95 ± 16 mmHg; P < .05) without preload or afterload modification. Oxygenation (PaO2/FiO2: 349 ± 87 vs 440 ± 75; P < .05) and static compliance (26.3 ± 7.4 vs 30.3 ± 7.8 ml/cmH2O; P < .05) were also impaired during two hours compared to baseline. No edema was noticed in either group whatever the lung considered. All measured cytokines were below the detection threshold. CONCLUSIONS: An isolated right lung contusion is associated with rapid but transient cardiorespiratory impairments. Despite the large extent of the lung contusion, no pulmonary edema appeared during the period studied.
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Edema Pulmonar/etiologia , Traumatismos Torácicos/complicações , Ferimentos não Penetrantes/complicações , Animais , Contusões/complicações , Contusões/patologia , Citocinas/sangue , Modelos Animais de Doenças , Feminino , Hemodinâmica , Pulmão/patologia , Lesão Pulmonar/complicações , Lesão Pulmonar/patologia , Edema Pulmonar/patologia , Suínos , Traumatismos Torácicos/patologia , Ferimentos não Penetrantes/patologiaRESUMO
BACKGROUND: We designed an algorithm to assess COVID-19 patients severity and dynamic intubation needs and predict their length of stay using the breathing frequency (BF) and oxygen saturation (SpO2) signals. METHODS: We recorded the BF and SpO2 signals for confirmed COVID-19 patients admitted to the ICU of a teaching hospital during both the first and subsequent outbreaks of the pandemic in France. An unsupervised machine-learning algorithm (the Gaussian mixture model) was applied to the patients' data for clustering. The algorithm's robustness was ensured by comparing its results against actual intubation rates. We predicted intubation rates using the algorithm every hour, thus conducting a severity evaluation. We designed a S24 severity score that represented the patient's severity over the previous 24 h; the validity of MS24, the maximum S24 score, was checked against rates of intubation risk and prolonged ICU stay. RESULTS: Our sample included 279 patients. . The unsupervised clustering had an accuracy rate of 87.8% for intubation recognition (AUC = 0.94, True Positive Rate 86.5%, true Negative Rate 90.9%). The S24 score of intubated patients was significantly higher than that of non-intubated patients at 48 h before intubation. The MS24 score allowed for the distinguishing between three severity levels with an increased risk of intubation: green (3.4%), orange (37%), and red (77%). A MS24 score over 40 was highly predictive of an ICU stay greater than 5 days at an accuracy rate of 81.0% (AUC = 0.87). CONCLUSIONS: Our algorithm uses simple signals and seems to efficiently visualize the patients' respiratory situations, meaning that it has the potential to assist staffs' in decision-making. Additionally, real-time computation is easy to implement.
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COVID-19 , Triagem , Cuidados Críticos , Humanos , Estudos Retrospectivos , SARS-CoV-2 , Aprendizado de Máquina não SupervisionadoRESUMO
We report the case of a civilian 27-year-old man treated in a military hospital in France who sustained multiple stab wounds, including one in the left groin, with massive external bleeding. When first responders arrived, the patient was in hemorrhagic shock. A tourniquet and two intraosseous catheters were placed to start resuscitative care. On the patient's arrival at the hospital, bleeding was not controlled, so a junctional tourniquet was put in place and massive transfusion was started. Surgical exploration revealed a laceration of the superficial femoral artery and a disruption of the femoral vein. Vascular damage control was achieved by a general surgeon and consisted of primary repair of the superficial femoral artery injury and venous ligation. The patient was discharged from the intensive care unit after 2 days and from the hospital after 8 days. This case illustrates some of the persistent challenges shared between military and civilian trauma care. The external control of junctional hemorrhage is not easily achievable in the field, and junctional tourniquets have been therefore incorporated in the Tactical Combat Casualty Care guidelines. French lyophilized plasma was used for massive transfusion because it has been proven to be a logistically superior alternative to fresh-frozen plasma. Management of vascular wounds by nonspecialized surgeons is a complex situation that requires vascular damage-control skills; French military surgeons therefore follow a comprehensive structured surgical training course that prepares them to manage complex penetrating trauma in austere environments. Finally, in this case, lessons learned on the battlefield were applied to the benefit of the patient.
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Medicina Militar , Choque Hemorrágico , Adulto , França , Hemorragia/terapia , Humanos , Masculino , TorniquetesRESUMO
AIM: Describing acute respiratory distress syndrome patterns, therapeutics management, and outcomes of ICU COVID-19 patients and indentifying risk factors of 28-day mortality. METHODS: Prospective multicentre, cohort study conducted in 29 French ICUs. Baseline characteristics, comorbidities, adjunctive therapies, ventilatory support at ICU admission and survival data were collected. RESULTS: From March to July 2020, 966 patients were enrolled with a median age of 66 (interquartile range 58-73) years and a median SAPS II of 37 (29-48). During the first 24 h of ICU admission, COVID-19 patients received one of the following respiratory supports: mechanical ventilation for 559 (58%), standard oxygen therapy for 228 (24%) and high-flow nasal cannula (HFNC) for 179 (19%) patients. Overall, 721 (75%) patients were mechanically ventilated during their ICU stay. Prone positioning and neuromuscular blocking agents were used in 494 (51%) and 460 (48%) patients, respectively. Bacterial co-infections and ventilator-associated pneumonia were diagnosed in 79 (3%) and 411 (43%) patients, respectively. The overall 28-day mortality was 18%. Age, pre-existing comorbidities, severity of respiratory failure and the absence of antiviral therapy on admission were identified as independent predictors of 28-day outcome. CONCLUSION: Severity of hypoxaemia on admission, older age (> 70 years), cardiovascular and renal comorbidities were associated with worse outcome in COVID-19 patients. Antiviral treatment on admission was identified as a protective factor for 28-day mortality. Ascertaining the outcomes of critically ill COVID-19 patients is crucial to optimise hospital and ICU resources and provide the appropriate intensity level of care.
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COVID-19 , SARS-CoV-2 , Idoso , Estudos de Coortes , Cuidados Críticos , Humanos , Unidades de Terapia Intensiva , Pessoa de Meia-Idade , Estudos Prospectivos , Respiração ArtificialRESUMO
As an aerosol and droplets generating procedure, tracheostomy increases contamination risks for health workers in the coronavirus disease context. To preserve the health care system capacity and to limit virus cross-transmission, protecting caregivers against coronavirus infection is of critical importance. We report the use of external fixator equipment to set up a physical interface between the patient's neck and the caregiver performing a tracheostomy in COVID-19 patients. Once the metal frame set in place, it is wrapped with a single-use clear and sterile cover for surgical C-arm. This installation is simple, easy, and fast to achieve and can be carried out with inexpensive material available in every hospital. This physical interface is an additional safety measure that prevents the direct projection of secretions or droplets. It should, of course, only be considered as a complement to strict compliance with barrier precautions and personal protective equipment.
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Infecções por Coronavirus/prevenção & controle , Transmissão de Doença Infecciosa do Paciente para o Profissional/prevenção & controle , Saúde Ocupacional , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Equipamentos de Proteção/estatística & dados numéricos , Traqueostomia/métodos , COVID-19 , China , Infecções por Coronavirus/epidemiologia , Desenho de Equipamento , Feminino , Pessoal de Saúde/estatística & dados numéricos , Humanos , Controle de Infecções/métodos , Masculino , Pandemias/estatística & dados numéricos , Pneumonia Viral/epidemiologia , Traqueostomia/instrumentaçãoRESUMO
INTRODUCTION: This study investigated invasive mechanical ventilation modalities used in severe blunt chest trauma patients with pulmonary contusion. Occurrence, risk factors, and outcomes of early onset acute respiratory distress syndrome were also evaluated. METHODS: We performed a retrospective multicenter observational study including 115 adult patients hospitalized in six level 1 trauma intensive care units between April and September of 2014. Independent predictors of early onset acute respiratory distress syndrome were determined by multiple logistic regression analysis based on clinical characteristics and initial management. RESULTS: Protective ventilation principles were highly implemented, even prophylactically before acute respiratory distress syndrome occurrence. Early onset acute respiratory distress syndrome appeared to be associated with lung contusion of >20% of total lung volume and early onset pneumonia. CONCLUSIONS: Predictors of early onset acute respiratory distress syndrome could help with identifying high-risk populations, potentially improving case management through specific protocol development for these patients.
RESUMO
PURPOSE: Patient data management systems (PDMS) are widely used in intensive care units (ICUs) to improve care traceability. Verbal orders are still used for prescriptions requiring immediate execution but should be subsequently recorded in the system. We assessed the rapid sequence induction (RSI) traceability for endotracheal intubation in an ICU dedicated PDMS. MATERIALS AND METHODS: A retrospective study was conducted on anonymous databases in 21 ICUs. Endotracheal tube insertions performed during one year were compared to the number of RSI registered in the PDMS. RESULTS: We listed 5516 endotracheal tube insertions. A suxamethonium injection was registered in 829 cases and a rocuronium administration in 909 cases. The RSI traceability rate in the overall cohort was 31.5% and was greater in the units where nurses were allowed to record a drug administration before the computerized physician order entry. CONCLUSIONS: PDMS are supposed to improve prescription completeness and traceability, but our study suggests an opposite result. A co-responsibility policy between physicians and nurses should be promoted to improve care traceability. PDMS ergonomic improvements and enhanced integration in clinical workflow might also result in better compliance with documentation requirements. In each centre, indicators of PDMS correct use should be defined and periodically monitored.
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Unidades de Terapia Intensiva , Sistemas de Registro de Ordens Médicas , Avaliação de Resultados em Cuidados de Saúde , Indução e Intubação de Sequência Rápida , França , Humanos , Estudos Retrospectivos , Inquéritos e QuestionáriosRESUMO
OBJECTIVES: This study aimed to assess the short-term respiratory tolerance and haemodynamic efficiency of low-volume resuscitation with hypertonic saline and hydroxyethylstarch (HS/HES) in a pig model of lung contusion and controlled haemorrhagic shock. We hypothesised that a low-volume of HS/HES after haemorrhagic shock did not impact contused lungs in terms of extravascular lung water 3hours after trauma. METHODS: A lung contusion resulting from blunt chest trauma was induced in 28 anaesthetised female pigs with five bolt-shots to the right thoracic cage, followed by haemorrhagic shock and fluid resuscitation. Pigs were randomly allocated into two groups: fluid resuscitation by 4ml/kg of HS/HES, or fluid resuscitation by 10ml/kg of normal saline (NS). Monitoring was based on transpulmonary thermodilution and a pulmonary artery catheter. After 3h, animals were euthanized to measure extravascular lung water (EVLW) by gravimetry. RESULTS: Blunt chest trauma was followed by a transient collapse and hypoxaemia in both groups. Post-mortem gravimetric assessment demonstrated a significant difference between EVLW in the NS-group (8.1±0.7ml/kg) and in the HS/HES-group (6.2±0.6ml/kg, P=0.038). Based on a pathological EVLW threshold of > 7ml/kg, results indicated that only the NS-group experienced moderate pulmonary oedema, contrary to the HS/HES-group. After haemorrhagic shock, HS/HES infusion enabled the restoration of effective mean arterial pressure and cardiac index. Intrapulmonary shunting increased transiently after fluid resuscitation but there was no significant impairment of oxygenation. CONCLUSION: In this pig model of lung contusion, the short-term assessment of fluid resuscitation after haemorrhagic shock with 4ml/kg of HS/HES showed that pulmonary oedema was avoided compared to fluid resuscitation with 10ml/kg of NS.
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Reanimação Cardiopulmonar/métodos , Contusões/terapia , Derivados de Hidroxietil Amido , Lesão Pulmonar/terapia , Solução Salina Hipertônica , Choque Hemorrágico/terapia , Animais , Reanimação Cardiopulmonar/efeitos adversos , Cateterismo de Swan-Ganz , Água Extravascular Pulmonar , Feminino , Hemodinâmica , Derivados de Hidroxietil Amido/efeitos adversos , Edema Pulmonar/etiologia , Edema Pulmonar/prevenção & controle , Testes de Função Respiratória , Solução Salina Hipertônica/efeitos adversos , Choque Hemorrágico/etiologia , Suínos , Termodiluição , Traumatismos Torácicos/terapia , Ferimentos não Penetrantes/terapiaAssuntos
Injúria Renal Aguda , COVID-19 , França , Humanos , Terapia de Substituição Renal , SARS-CoV-2Assuntos
Pneumonia Viral , Traqueotomia , Betacoronavirus , COVID-19 , Infecções por Coronavirus , Humanos , Pandemias , SARS-CoV-2 , TraqueostomiaRESUMO
INTRODUCTION: Ebola Virus Disease (EVD) causes severe diarrhoea and vomiting, leading to dehydration and electrolyte abnormalities. Treatment remains supportive and often requires intravenous (IV) access. IV catheters are difficult to insert and maintain in this context. Our primary objective was to compare peripheral venous catheters (PVCs) and central venous catheters (CVCs) for volume resuscitation in patients with EVD. MATERIAL AND METHODS: We performed a prospective observational study between January and March 2015 at the Conakry Healthcare Workers Ebola Treatment Unit (ETU). The primary judgement criterion was the ratio of the daily infused volume of fluids to the prescribed volume (DIV/PV). RESULTS: Fourteen patients were admitted. Twenty-eight PVCs and 8 CVCs were inserted. CVCs had a longer survival time (96 ± 34 hours versus 33.5 ± 21 hours, P<0.001). The mean DIV/PV was higher for the CVCs (0.95±0.08 versus 0.7 ± 0.27, P<0.001), as well as the number of days with full administration of prescribed IV fluids (71.2% versus 34.1%, P=0.002). DISCUSSION: Inserting CVCs is a safe and reliable way of obtaining IV access in ETUs, provided adequately trained personnel are available. CVCs optimize fluid infusion compared to PVCs. Further studies comparing fluid management strategies in EVD are necessary.
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Cateterismo Venoso Central/métodos , Cateterismo Periférico/métodos , Hidratação/métodos , Doença pelo Vírus Ebola/terapia , Adulto , Idoso , Cateterismo Venoso Central/efeitos adversos , Cateterismo Periférico/efeitos adversos , Catéteres/efeitos adversos , Cateteres Venosos Centrais/efeitos adversos , Feminino , Hidratação/efeitos adversos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Ressuscitação , Análise de SobrevidaRESUMO
The complexation of lanthanides(III) by the tripodal ligands tpa (tris[(2-pyridyl)methyl]amine) and tpza (tris[(2-pyrazinyl)methyl]amine) has been investigated by solution NMR studies and by X-ray crystallography. The crystallographic studies show that both tpa and the new ligand tpza form complexes with a 1:1 metal:ligand ratio in which the tripodal amine acts as a tetradentate ligand. For the tpa complexes the remaining coordination sites are occupied by chloride counterions to give 7-coordination (Eu, Tb, Lu) or by chloride counterions and a methanol molecule to give 8-coordination (Nd). In [Nd(tpza)(H(2)O)(3)(CH(3)CN)(3)](ClO(4))(3).3H(2)O the remaining coordination sites are occupied by water and acetonitrile molecules to give 10-coordination while the perchlorate counterions remain non coordinating. Tpza complexes have been isolated from acetonitrile solution and dissociate completely in methanol, while the complexes of the more basic tpa can be isolated from methanol and exist in water in equilibrium with the free ligand. Solvent extraction studies of lanthanides(III) and actinides(III) from nitric acid solutions show that the new ligand tpza is, unlike tpa, a selective complexant of actinides(III). Considering their structural analogy, this difference could be explained in terms of the electronic differences between the two ligands resulting in a stronger affinity of actinides(III) for the softer donor tpza.