Marcos Melo

Marcos Melo
Partners HealthCare

About

210
Publications
18,011
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
5,536
Citations
Citations since 2016
91 Research Items
3452 Citations
20162017201820192020202120220100200300400500600
20162017201820192020202120220100200300400500600
20162017201820192020202120220100200300400500600
20162017201820192020202120220100200300400500600
Introduction

Publications

Publications (210)
Article
Acute respiratory distress syndrome (ARDS) is a common lung disorder that involves severe inflammatory damage in the pulmonary barrier, but the underlying mechanisms remain elusive. Here, we demonstrated that pulmonary macrophages originating from ARDS patients and mice caused by bacteria were characterized by increased expression of ferroportin (F...
Article
Background: The impact of high vs low intraoperative tidal volumes on postoperative respiratory complications remains unclear. We hypothesised that the effect of intraoperative tidal volume on postoperative respiratory complications is dependent on respiratory system elastance. Methods: We retrospectively recorded tidal volume (Vt; ml kg-1 ideal...
Article
BACKGROUND Reintubation after lung cancer resection is an important quality metric due to increased disability, mortality and cost. However, no validated predictive instrument is in use to reduce reintubation after lung resection. We aimed to create and validate the PRediction Of REintubation After Lung cancer resection (PROREAL) score. METHODS We...
Article
Full-text available
Background: Adjuvant regional anesthesia is often selected for patients or procedures with high risk of pulmonary complications after general anesthesia. The benefit of adjuvant regional anesthesia to reduce postoperative pulmonary complications remains uncertain. In a prospective observational multicenter study, patients scheduled for non-cardiot...
Article
Full-text available
Atelectasis is a frequent clinical condition, yet knowledge is limited and controversial on its biological contribution towards lung injury. We assessed the regional proteomics of atelectatic versus normally-aerated lung tissue to test the hypothesis that immune and alveolar-capillary barrier functions are compromised by purely atelectasis and dysr...
Article
Full-text available
The present study describes the magnitude and spatial distribution of lung strain in healthy anesthetized, mechanically ventilated dogs with and without positive end-expiratory pressure (PEEP). Total lung strain (LSTOTAL) has a dynamic (LSDYNAMIC) and a static (LSSTATIC) component. Due to lung heterogeneity, global lung strain may not accurately re...
Article
Full-text available
Background The aim of this analysis is to determine geo–economic variations in epidemiology, ventilator settings and outcome in patients receiving general anesthesia for surgery. Methods Posthoc analysis of a worldwide study in 29 countries. Lower and upper middle–income countries (LMIC and UMIC), and high–income countries (HIC) were compared. The...
Chapter
The practice of thoracic anesthesia involves not only patients with impaired pulmonary function, it also necessitates dynamic changes in ventilation with resulting impact on perfusion and ventilation/perfusion matching. Thus it is imperative that the thoracic anesthesiologist has a thorough understanding of the normal pulmonary physiology, as well...
Article
Full-text available
Background Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods In thi...
Article
Full-text available
The development of pulmonary atelectasis is common in the surgical patient. Pulmonary atelectasis can cause various degrees of gas exchange and respiratory mechanics impairment during and after surgery. In its most serious presentations, lung collapse could contribute to postoperative respiratory insufficiency, pneumonia, and worse overall clinical...
Article
Full-text available
Pulmonary atelectasis is common in the perioperative period. Physiologically, it is produced when collapsing forces derived from positive pleural pressure and surface tension overcome expanding forces from alveolar pressure and parenchymal tethering. Atelectasis impairs blood oxygenation and reduces lung compliance. It is increasingly recognized th...
Article
A 75-year-old woman with a history of right-upper lobectomy for adenocarcinoma presented for a right completion pneumonectomy due to 2 new fluorodeoxyglucose-avid densities on the remaining lung. After uneventful anesthetic induction and surgical resection with modest blood loss, the patient developed refractory hypoxemia on emergence without signi...
Article
Full-text available
Background It is uncertain whether the association of the intraoperative driving pressure (ΔP) with postoperative pulmonary complications (PPCs) depends on the surgical approach during abdominal surgery. Our primary objective was to determine and compare the association of time–weighted average ΔP (ΔP TW ) with PPCs. We also tested the association...
Article
BACKGROUND One key element of lung-protective ventilation is the use of a low tidal volume (VT). A sex difference in use of low tidal volume ventilation (LTVV) has been described in critically ill ICU patients. OBJECTIVES The aim of this study was to determine whether a sex difference in use of LTVV also exists in operating room patients, and if pr...
Article
Background: Anaemia is frequently recorded during preoperative screening and has been suggested to affect outcomes after surgery negatively. Objectives: The objectives were to assess the frequency of moderate to severe anaemia and its association with length of hospital stay. Design: Post hoc analysis of the international observational prospec...
Article
Full-text available
To evaluate a compact and easily interpretable 4-parameter model describing the shape of the volumetric capnogram, and the resulting estimates of anatomical dead space (VDAW) and Phase III (alveolar plateau) slope (SIII). Data from of 8 mildly-endotoxemic pre-acute respiratory distress syndrome sheep were fitted to the proposed 4-parameter model (4...
Article
Full-text available
Background: Limited information is available regarding intraoperative ventilator settings and the incidence of postoperative pulmonary complications (PPCs) in patients undergoing neurosurgical procedures. The aim of this post-hoc analysis of the 'Multicentre Local ASsessment of VEntilatory management during General Anaesthesia for Surgery' (LAS VE...
Preprint
Full-text available
Background: It is uncertain whether associations between driving pressure (ΔP) during and occurrence of pulmonary complications after abdominal surgery depend on the surgical approach. Our primary objective was to test the time–weighted average ΔP (ΔPTW) association with postoperative pulmonary complications and our secondary objective was to test...
Article
Full-text available
Background International data on the epidemiology, ventilation practice, and outcomes in patients undergoing abdominal robotic-assisted surgery (RAS) are lacking. The aim of the study was to assess the incidence of postoperative pulmonary complications (PPCs), and to describe ventilator management after abdominal RAS. Methods This was an internati...
Article
Full-text available
Positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) has been increasingly applied, predominantly in the research setting, to study drug effects and pulmonary biology and monitor disease progression and treatment outcomes in lung diseases, disorders that interfere with gas exchange through alterations of the pulmonary parenchyma...
Article
Background We aimed to investigate the physiological mechanism and spatial distribution of increased physiological dead‐space, an early marker of ARDS mortality, in the initial stages of ARDS. We hypothesized that: increased dead‐space results from the spatial redistribution of pulmonary perfusion, not ventilation; such redistribution is not relate...
Article
Background: In the Protective Ventilation in Cardiac Surgery (PROVECS) randomized, controlled trial, an open-lung ventilation strategy did not improve postoperative respiratory outcomes after on-pump cardiac surgery. In this prespecified subanalysis, the authors aimed to assess the regional distribution of ventilation and plasma biomarkers of lung...
Article
Full-text available
Background: Pulmonary atelectasis is frequent in clinical settings. Yet there is limited mechanistic understanding and substantial clinical and biologic controversy on its consequences. The authors hypothesize that atelectasis produces local transcriptomic changes related to immunity and alveolar-capillary barrier function conducive to lung injury...
Article
Full-text available
Background: Intraoperative mechanical ventilation may influence postoperative pulmonary complications (PPCs). Current practice during thoracic surgery is not well described. Methods: This is a post-hoc analysis of the prospective multicenter cross-sectional LAS VEGAS study focusing on patients who underwent thoracic surgery. Consecutive adult pa...
Article
Background Higher intraoperative driving pressures (ΔP) are associated with increased postoperative pulmonary complications (PPC). We hypothesised that dynamic adjustment of PEEP throughout abdominal surgery reduces ΔP, maintains positive end-expiratory transpulmonary pressures (Ptp_ee) and increases respiratory system static compliance (Crs) with...
Article
Full-text available
Rationale and Objectives Pulmonary atelectasis presumably promotes and facilitates lung injury. However, data are limited on its direct and remote relation to inflammation. We aimed to assess regional 2-deoxy-2-[¹⁸F]-fluoro-D-glucose (¹⁸F-FDG) kinetics representative of inflammation in atelectatic and normally aerated regions in models of early lun...
Article
Full-text available
Background High ventilatory frequencies increase static lung strain and possibly lung stress by shortening expiratory time, increasing intrathoracic pressure, and causing dynamic hyperinflation. We hypothesised that high intraoperative ventilatory frequencies were associated with postoperative respiratory complications. Methods In this retrospecti...
Article
Background: Mechanical ventilation with variable tidal volumes (VT) may improve lung function and reduce ventilator-induced lung injury in experimental acute respiratory distress syndrome (ARDS). However, previous investigations were limited to less than 6 h, and control groups did not follow clinical standards. We hypothesised that 24 h of mechan...
Article
Purpose To evaluate whether a perioperative open-lung ventilation strategy prevents postoperative pulmonary complications after elective on-pump cardiac surgery. Methods In a pragmatic, randomized, multicenter, controlled trial, we assigned patients planned for on-pump cardiac surgery to either a conventional ventilation strategy with no ventilati...
Article
Background: Pneumoperitoneum and nonphysiological positioning required for robotic surgery increase cardiopulmonary risk because of the use of larger airway pressures (Paws) to maintain tidal volume (VT). However, the quantitative partitioning of respiratory mechanics and transpulmonary pressure (PL) during robotic surgery is not well described. W...
Article
The physiologic concept, pathophysiologic implications, and clinical relevance and application of driving pressure and transpulmonary pressure to prevent ventilator-induced lung injury are discussed.
Article
Full-text available
Objectives: To determine the impact of positive end-expiratory pressure during mechanical ventilation with and without spontaneous breathing activity on regional lung inflammation in experimental nonsevere acute respiratory distress syndrome. Design: Laboratory investigation. Setting: University hospital research facility. Subjects: Twenty-f...
Article
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 pros...
Article
Rationale: Low tidal volume ventilation might protect healthy lungs from volutrauma but lead to inflammation from other mechanisms, namely alveolar derecruitment and the ensuing alveolar collapse and reexpansion. Objective: We hypothesized that the different mechanisms of low and high volume injury would be reflected in different mechanical prop...
Article
Full-text available
Introduction Robotic-assisted surgery (RAS) has emerged as an alternative minimally invasive surgical option. Despite its growing applicability, the frequent need for pneumoperitoneum and Trendelenburg position could significantly affect respiratory mechanics during RAS. AVATaR is an international multicenter observational study aiming to assess th...
Article
Introduction: Spatial heterogeneity of lung aeration and strain (change volume/resting volume) occurs at microscopic levels and contributes to lung injury. Yet, it is mostly assessed with histograms or large regions-of-interest. Spatial heterogeneity could also influence regional gene expression. We used positron emission tomography (PET)/computed...
Article
Background: There is limited information concerning the current practice of intraoperative mechanical ventilation in obese patients, and the optimal ventilator settings for these patients are debated. We investigated intraoperative ventilation parameters and their associations with the development of postoperative pulmonary complications (PPCs) in...
Article
Full-text available
Background: Currently used pre-operative prediction scores for postoperative pulmonary complications (PPCs) use patient data and expected surgery characteristics exclusively. However, intra-operative events are also associated with the development of PPCs. Objective: We aimed to develop a new prediction score for PPCs that uses both pre-operativ...
Article
Background: Biological phenotypes have been identified within several heterogeneous pulmonary diseases, with potential therapeutic consequences. Objective: To assess whether distinct biological phenotypes exist within surgical patients, and whether development of postoperative pulmonary complications (PPCs) and subsequent dependence of intra-ope...
Article
Rationale: The contribution of aeration heterogeneity to lung injury during early mechanical ventilation of uninjured lungs is unknown. Objective: Test the hypotheses that a strategy consistent with clinical practice does not protect from worsening in lung strains during the first 24h of ventilation of initially normal lungs exposed to mild syst...
Article
Full-text available
Background: The majority of critically ill patients do not suffer from acute respiratory distress syndrome (ARDS). To improve the treatment of these patients, we aimed to identify potentially modifiable factors associated with outcome of these patients. Methods: The PRoVENT was an international, multicenter, prospective cohort study of consecuti...
Article
Numerous preclinical studies support the role of spinal neuroimmune activation in the pathogenesis of chronic pain, and targeting glia (e.g., microglia/astrocyte)- or macrophage-mediated neuroinflammatory responses effectively prevents or reverses the establishment of persistent nocifensive behaviors in laboratory animals. However, thus far the tra...
Article
Rationale: In ARDS, atelectatic 'solid-like' lung tissue impairs transmission of negative 'swings' in pleural pressure (Ppl) resulting from diaphragmatic contraction. The localization of more negative Ppl proportionally increases dependent lung stretch by drawing gas either from other lung regions, e.g., non-dependent lung (Pendelluft) or from the...