Laurent Bitker

Laurent Bitker
Creatis Medical Imaging Research Center · Department of Medical Imaging

MD PhD

About

80
Publications
13,171
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
854
Citations

Publications

Publications (80)
Article
Full-text available
Background PEEP selection in severe COVID-19 patients under extracorporeal membrane oxygenation (ECMO) is challenging as no study has assessed the alveolar recruitability in this setting. The aim of the study was to compare lung recruitability and the impact of PEEP on lung aeration in moderate and severe ARDS patients with or without ECMO, using c...
Article
Full-text available
Background While antibiotic therapy is advocated to improve outcomes in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) whenever mechanical ventilation is required, the evidence relies on small studies carried out before the era of widespread antibiotic resistance. Furthermore, the impact of systematic antibiotic therapy on suc...
Article
Full-text available
Background Fluid overload is associated with worse outcome in critically ill patients requiring continuous renal replacement therapy (CRRT). Net ultrafiltration (UFNET) allows precise control of the fluid removal but is frequently ceased due to hemodynamic instability episodes. However, approximately 50% of the hemodynamic instability episodes in I...
Article
Objectives: The aim of the present study was to investigate the level of cardiorespiratory fitness and neuromuscular function of ICU survivors after COVID-19 and to examine whether these outcomes are related to ICU stay/mechanical ventilation duration. Design: Prospective nonrandomized study. Setting: Patients hospitalized in ICU for COVID-19...
Article
In patients with the acute respiratory distress syndrome (ARDS), lung imaging is a fundamental tool in the study of the morphological and mechanistic features of the lungs. Chest computed tomography studies led to major advances in the understanding of ARDS physiology. They allowed the in vivo study of the syndrome's lung features in relation with...
Article
Purpose: To assess short-term creatinine changes as predictors of acute kidney injury (AKI) when used alone and in combination with AKI risk factors. Methods: In this prospective cohort study, we identified all creatinine measurements from frequent point-of-care arterial blood gas measurements from ICU admission until AKI. We evaluated the predi...
Article
Objective: Admission in the intensive care unit of the old patient with coronavirus disease 19 raises an ethical question concerning the scarce resources and their short-term mortality. Methods: Patients aged over 60 from 7 different intensive care units admitted between March 1, 2020 and May 6, 2020, with a diagnosis of coronavirus disease 19 w...
Article
Full-text available
Purpose Imaging of acute lung inflammation is pivotal to evaluate innovative ventilation strategies. We aimed to develop and validate a three-tissue compartment kinetic model (3TCM) of [¹¹C](R)-PK11195 lung uptake in experimental acute respiratory distress syndrome (ARDS) to help quantify macrophagic inflammation, while accounting for the impact of...
Article
Full-text available
Background The current standard of care during severe acute respiratory distress syndrome (ARDS) is based on low tidal volume (VT) ventilation, at 6 mL/kg of predicted body weight. The time-controlled adaptive ventilation (TCAV) is an alternative strategy, based on specific settings of the airway pressure release ventilation (APRV) mode. Briefly, T...
Article
Full-text available
Objective To compare old patients hospitalized in ICU for respiratory distress due to COVID-19 with old patients hospitalized in ICU for a non-COVID-19-related reason in terms of autonomy and quality of life. Design Comparison of two prospective multi-centric studies. Setting This study was based on two prospective multi-centric studies, the Seni...
Article
The SARS-COV2 pandemic induces tensions on health systems and ethical dilemmas. Practitioners need help tools to define patients not candidate for ICU admission. A multicentre observational study was performed to evaluate the impact of age and geriatric parameters on 30-day mortality in patients aged ≥60 years of age. Patients or next of kin were a...
Article
Full-text available
Background Lymphopenia is a hallmark of severe coronavirus disease 19 (COVID-19). Similar alterations have been described in bacterial sepsis and therapeutic strategies targeting T cell function such as recombinant human interleukin 7 (rhIL-7) have been proposed in this clinical context. As COVID-19 is a viral sepsis, the objectives of this study w...
Article
Full-text available
Abstract Background Hemodynamic instability is a frequent complication of continuous renal replacement therapy (CRRT). Postural tests (i.e., passive leg raising in the supine position or Trendelenburg maneuver in the prone position) combined with measurement of cardiac output are highly reliable to identify preload-dependence and may provide new in...
Article
Full-text available
Background Personalizing mechanical ventilation requires the development of reliable bedside monitoring techniques. The multiple-breaths nitrogen washin–washout (MBNW) technique is currently available to measure end-expiratory lung volume (EELV MBNW ), but the precision of the technique may be poor, with percentage errors ranging from 28 to 57%. Th...
Article
Purpose: Antibiotics are frequently used in patients receiving intermittent or continuous renal replacement therapy (RRT). Continuous renal replacement may alter the pharmacokinetics (PK) and the ability to achieve PK/pharmacodynamic (PD) targets. Therapeutic drug monitoring (TDM) could help evaluate drug exposure and guide antibiotic dosage adjus...
Article
Background: Crystalloids, 4% albumin and 20% albumin are used for fluid bolus therapy (FBT) in patients after cardiac surgery. However, their detailed early (30 min) hemodynamic effects remain unstudied. Methods: In a comparative prospective observational trial of 120 ventilated, we studied post cardiac surgery patients who received crystalloid 500...
Article
Full-text available
Background Acute respiratory distress syndrome (ARDS) is a severe complication of COVID-19 pneumonia, with a mortality rate amounting to 34–50% in moderate and severe ARDS, and is associated with prolonged duration of invasive mechanical ventilation. Such as in non-COVID ARDS, harmful mechanical ventilation settings might be associated with worse o...
Article
Full-text available
Background The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruit...
Article
Full-text available
Introduction With the spread of COVID-19 epidemic, health plans must be adapted continuously. There is an urgent need to define the best care courses of patients with COVID-19, especially in intensive care units (ICUs), according to their individualised benefit/risk ratio. Since older age is associated with poorer short-term and long-term outcomes,...
Article
Full-text available
PurposeWe compared a restrictive fluid management strategy to usual care among critically ill patients with acute kidney injury (AKI) who had received initial fluid resuscitation.Methods This multicenter feasibility trial randomized 100 AKI patients 1:1 in seven ICUs in Europe and Australia. Restrictive fluid management included targeting negative...
Article
Full-text available
Introduction: The contribution of fluid temperature to the effect of crystalloid fluid bolus therapy (FBT) in post-cardiac surgery patients is unknown. We evaluated the hemodynamic effects of FBT with fluid warmed to 40°C (warm FBT) versus room-temperature fluid. Methods: In this single centre prospective before-and-after study, we evaluated the...
Article
OBJECTIVE: To study the temperature and haemodynamic effects of room versus body temperature 20% albumin fluid bolus therapy (FBT). DESIGN: Single-centre, prospective, before–after trial. SETTING: A tertiary intensive care unit (ICU) in Australia. PARTICIPANTS: Sixty ventilated post-cardiac surgery patients. INTERVENTION: Room versus body temperatu...
Preprint
Full-text available
Background Hemodynamic instability is a frequent complication of continuous renal replacement therapy (CRRT). Postural tests (i.e. passive leg raising in the supine position or Trendelenburg maneuver in the prone position) combined with measurement of cardiac output are highly reliable to identify preload-dependence and may provide new insights int...
Article
Full-text available
Background Data on respiratory mechanics of COVID-19 ARDS patients are scarce. Respiratory mechanics and response to positive expiratory pressure (PEEP) may be different in obese and non-obese patients. Methods We investigated esophageal pressure allowing determination of transpulmonary pressures (PL ) and elastances (EL) during a decremental PEEP...
Article
Full-text available
Background Protracted viral shedding is common in hospitalized patients with COVID-19 pneumonia, and up to 40% display signs of pulmonary fibrosis on computed tomography (CT) after hospital discharge. We hypothesized that COVID-19 patients with acute respiratory failure (ARF) who die in intensive care units (ICU) have a lower viral clearance in the...
Article
Background: Near-infrared spectroscopy (NIRS) is used routinely to monitor cerebral tissue oxygen saturation (SctO2) during cardiopulmonary bypass (CPB) but is rarely employed outside the operating room. Previous studies indicate that patients are at risk of postoperative cerebral oxygen desaturation after cardiac surgery. Objectives: We aimed t...
Article
Objectives: To describe the hemodynamic response to fluid boluses for hypotension in children in a cardiac ICU. Design: A prospective, observational study. Setting: Single-centered cardiac ICU. Patients: Children in a cardiac ICU with hypotension. Interventions: Clinician prescribed fluid bolus. Measurements and main results: Sixty-four...
Presentation
Full-text available
In this prospective cohort study, we assessed all the creatinine values from ABGs and laboratory biochemistry results in critically ill patients. We calculated the small, short-term creatinine increases between creatinine values during the patient’s Intensive Care Unit (ICU) admission until the development of KDIGO-defined AKI or ICU discharge or d...
Chapter
Acute respiratory distress syndrome (ARDS) is a critical impairment of the lung function, which occurs – among others – in severe cases of patients with Covid-19. Its therapeutic management is based on mechanical ventilation, but this may aggravate the patient’s condition if the settings are not adapted to the actual lung state. Computed tomography...
Article
Purpose The aim of this study was to assess whether the computed tomography (CT) features of COVID-19 (COVID+) ARDS differ from those of non-COVID-19 (COVID−) ARDS patients. Materials and methods The study is a single-center prospective observational study performed on adults with ARDS onset ≤72 h and a PaO2/FiO2 ≤ 200 mmHg. CT scans were acquired...
Article
Background: Frequent assessment of urine output (UO), serum creatinine (sCr) and urinary cell cycle arrest biomarkers (CCAB) may improve acute kidney injury (AKI) prediction. Objective: To study the performance of UO, short term sCr changes and urinary CCAB to predict severe AKI. Methods: We measured 6 hours of UO, 6-hourly sCr changes, and ur...
Article
Objective To compare the hemodynamic effect of room temperature (cold) 4% albumin fluid bolus therapy (FBT) with body temperature (warm) albumin FBT. Design Prospective, before-after trial. Setting A tertiary intensive care unit (ICU). Participant Sixty ventilated, post-cardiac surgery patients prescribed with 4% albumin FBT. Intervention Cold...
Article
Full-text available
Background: Chronic kidney disease (CKD) after lung transplantation (LT) is underestimated. The aim of the present study was to measure the loss of glomerular filtration rate (GFR) 1 year after LT and to identify the risk factors for developing Stage ≥3 CKD. Methods: LT patients in the University Hospital of Lyon had a pre- and post-transplantat...
Article
Objective We aimed to test whether a bolus of magnesium followed by continuous intravenous infusion might prevent the development of AF after cardiac surgery. Design Sequential, matched, case-controlled pilot study Setting Tertiary university hospital Participants Matched cohort of 99 patients before and intervention cohort of 99 consecutive pat...
Article
Full-text available
COVID patients in ICU present a high mortality rate and immunoprofiling reveals heterogeneous IFN-α2 production with about 20% of critically-ill patients unable to produce IFN-α2, highlighting the immune response heterogeneity and opening avenues for targeted therapies.
Article
Full-text available
Objective: To study the cardiovascular effect over 30 minutes following the end of fluid bolus therapy (FBT) with 20% albumin in patients after cardiac surgery. Design: Prospective observational study. Setting: Intensive care unit of a tertiary university-affiliated hospital. Participants: Twenty post-cardiac surgery mechanically ventilated...
Article
Background: Continuous renal replacement therapy (CRRT) technique may affect circuit lifespan. A shorter circuit life may reduce CRRT efficacy and increase costs. Methods: In a before-and-after study, we compared circuit median survival time during continuous venovenous hemofiltration (CVVH) versus continuous venovenous hemodialysis (-CVVHD). We...
Article
Full-text available
Background: Fluid accumulation frequently coexists with acute kidney injury (AKI) and is associated with increased risk for AKI progression and mortality. Among septic shock patients, restricted use of resuscitation fluid has been reported to reduce the risk of worsening of AKI. Restrictive fluid therapy, however, has not been studied in the setti...
Article
IMPORTANCE It is unclear whether vitamin C, hydrocortisone, and thiamine are more effective than hydrocortisone alone in expediting resolution of septic shock. OBJECTIVE To determine whether the combination of vitamin C, hydrocortisone, and thiamine, compared with hydrocortisone alone, improves the duration of time alive and free of vasopressor adm...
Article
Objective: To compare the physiological and biochemical effects of a single intravenous dose of furosemide or acetazolamide in critically ill patients. Design: Single centre, pilot randomised controlled trial. Setting: Large tertiary adult intensive care unit (ICU). Participants: Twenty-six adult ICU patients deemed to require diuretic thera...
Article
Objectives: To study vitamin C pharmacokinetics in septic shock. Design: Prospective pharmacokinetic study. Setting: Two intensive care units. Participants: Twenty-one patients with septic shock enrolled in a randomised trial of high dose vitamin C therapy in septic shock. Intervention: Patients received 1.5 g intravenous vitamin C every 6...
Article
Full-text available
Purpose Mechanical ventilation with ultra-low tidal volume (VT) during ARDS may reduce alveolar strain, driving pressure and hence ventilator-induced lung injury, with the main drawback of worsening respiratory acidosis. We hypothesized that VT could be reduced down to 4 ml/kg, with clinically significant decrease in driving pressure, without the n...
Article
Objective: To conduct a pilot feasibility and physiologic efficacy study of high-dose vitamin C in patients with vasoplegia after cardiac surgery. Design: Prospective, double-blind, randomized, controlled trial. Setting: Two tertiary intensive care units (ICUs). Participants: Post-cardiac surgery patients with vasoplegia. Interventions: Th...
Article
Background: Renal medullary hypoxia precedes the development of acute kidney injury in experimental sepsis and can now be assessed by continuous measurement of urinary oxygen tension (PuO2). Objectives: We aimed to test if PuO2 measurements in patients with septic shock would be similar to those shown in experimental sepsis and would detect chan...
Article
Background: Macrophagic lung infiltration is pivotal in the development of lung biotrauma due to ventilation-induced lung injury (VILI). We assessed the performance of [11C](R)-PK11195, positron emission tomography (PET) radiotracer binding the translocator protein (TSPO), to quantify macrophage lung recruitment during experimental VILI. Methods:...
Article
Objective: To assess the effects of sepsis and exogenous insulin on C-peptide levels and C-peptide to insulin ratios in intensive care unit (ICU) patients with type 2 diabetes mellitus (T2DM). Design, setting and participants: In this prospective, observational, single-centre study, we enrolled 31 ICU-admitted adults with T2DM. We measured serum C...
Article
Purpose: We assessed the incidence, characteristics, outcomes and associations of small, short-term point-of-care creatinine increases in critically ill patients. Methods: We prospectively identified the first episode of small (>1 μmol/L/h) short-term (3-4 h) point-of-care creatinine increase between two sequential arterial blood gas measurement...
Article
Classic and nonclassic renin-angiotensin systems (RAS) are 2 sides of an ubiquitous endocrine/paracrine cascade regulating blood pressure and homeostasis. Angiotensin II and angiotensin-converting enzyme (ACE) levels are associated with severity of disease in the critically ill, and are central to the physiology and the pathogenesis of circulatory...
Article
Full-text available
Background Hemodynamic response to prone position (PP) has never been studied in a large series of patients with acute respiratory distress syndrome (ARDS). The primary aim of this study was to estimate the rate of PP sessions associated with cardiac index improvement. Secondary objective was to describe hemodynamic response to PP and during the sh...
Article
Background: Pulmonary arterial hypertension (PAH) may lead to right heart failure and subsequently alter glomerular filtration rates (GFR). Chronic kidney disease (CKD, GFR <60 mL/min/1.73 m2) may also adversely affect PAH prognosis. This study aimed to assess how right heart hemodynamics was associated with reduced estimated GFR (eGFR) and the as...
Article
Full-text available
Background Predicting fluid responsiveness may help to avoid unnecessary fluid administration during acute respiratory distress syndrome (ARDS). The aim of this study was to evaluate the diagnostic performance of the following methods to predict fluid responsiveness in ARDS patients under protective ventilation in the prone position: cardiac index...