Assessing of low-tech solutions for aerosol delivery: Comparative performance study of manufactured versus homemade spacers.

PURPOSE: This study aims to evaluate the performance of low-cost homemade spacers compared with manufactured valved holding chambers (VHCs) for fluticasone propionate delivery via a pMDI (pressurized Metered Dose Inhaler). METHODS: The Total Emitted Dose (TED) and particle size distribution were measured for pMDI alone or connected to the different spacers, according to CAN/CSA-Z264.1-02 standard. Two types of low-cost alternative and manufactured spacers were investigated: 500 mL plastic bottle and 553 mL aluminium can; non-antistatic plastic VHCs and aluminium antistatic VHCs. RESULTS: The TED of homemade plastic bottle vs plastic VHC were similar in the 20-23% range. In contrast, the TED of homemade aluminium can was higher compared to aluminium VHC (83% vs 68%). The Fine Particle Fraction (FPF) was similar for the two plastic-based spacers (in the 12.68-17.60% range), although it was greater for the aluminium can compared to aluminium VHC (51% vs 42%). However, all spacers have limited large particles fraction, mainly deposited in the oropharyngeal tract, potentially decreasing side effects. CONCLUSION: We demonstrated that low-tech solutions as homemade spacers have at least similar performances to VHC medical devices composed of same material (aluminium or plastic). Thus, low-cost homemade spacers represent alternatives in case of emergency and without VHCs nearby.

Remote ischemic conditioning in septic shock: the RECO-Sepsis randomized clinical trial.

PURPOSE: To determine whether remote ischemic conditioning (RECO), compared to standard care, limits the severity and the consequences of multiple organ failure in patients with septic shock. METHODS: The RECO-Sepsis trial, a prospective, multicenter, randomized, open-label, parallel group trial with blinded assessment of the outcome, was conducted at six intensive care units in France in adult patients with septic shock. Within 12 h after the onset of septic shock, patients were randomized (1:1 ratio) to receive either RECO applied by inflating/deflating (200/0 mmHg for 5/5 min) 4 times a cuff around an arm or a sham procedure every 12 h for 24 h. The primary endpoint was the severity of multiple organ failure assessed by the mean daily Sequential Organ Failure Assessment (SOFA) score from inclusion to the fourth day after inclusion (day 4). Patients were followed for 90 days. RESULTS: Among 180 randomized patients, 178 completed the trial (RECO group: 87; control group: 91) and were included in the intention-to-treat analysis (108 men [60.7%], median age 68 [59-75] years). There was no significant difference in the mean daily SOFA score between the intervention group and the control group (7.2 points [5.2-10.7] versus 7.6 points [4.9-10.7], respectively; p = 0.919). Cumulative mortality within 90 days was 27.6% in the RECO group and 39.6% control group (Log-rank test, p = 0.10; adjusted hazard ratio 0.59, 95% CI, 0.35 to 0.99; p = 0.049). CONCLUSIONS: In patients with septic shock, RECO failed to reduce the severity of organ failures assessed by mean daily SOFA score from inclusion to day 4. Adequately powered trials are needed to assess potential delayed benefits of RECO.

Nebulised Gadolinium-Based Nanoparticles for a Multimodal Approach: Quantitative and Qualitative Lung Distribution Using Magnetic Resonance and Scintigraphy Imaging in Isolated Ventilated Porcine Lungs.

PURPOSE: This study aims at determining lung distribution of gadolinium-based polysiloxane nanoparticles, AGuIX® (small rigid platform - SRP), as a potential theranostic approach by the pulmonary route. METHODS: First, the aerodynamic size distribution and the aerosol output rate were thoroughly characterized. Then, a multimodal approach using magnetic resonance (MR) and gamma-camera (GC) imaging allows to assess the deposition of the aerosolised nanoparticles in the respiratory tract using isolated ventilated porcine lungs. RESULTS: The SRP has proven to be radiolabelled by radioisotope with a good yield. Crude SRP or radiolabelled ones showed the same aerodynamic size distribution and output as a conventional molecular tracer, as sodium fluoride. With MR and GC imaging approaches, the nebulised dose represented about 50% of the initial dose of nanoparticles placed in the nebuliser. Results expressed as proportions of the deposited aerosol showed approximately a regional aerosol deposition of 50% of the deposited dose in the lungs and 50% in the upper airways. Each technique assessed a homogeneous pattern of deposited nanoparticles in Lungs. MR observed a strong signal enhancement with the SRP, similar to the one obtained with a commonly used MRI contrast agent, gadoterate meglumine. CONCLUSION: As a known theranostic approach by intravenous administration, SRP appeared to be easily aerosolised with a conventional nebuliser. The present work proves that pulmonary administration of SRP is feasible in a human-like model and allows multimodal imaging with MR and GC imaging. This work presents the proof of concept of SRP nebulisation and aims to generate preclinical data for the potential clinical transfer of SRP for pulmonary delivery.

Towards Optimization of Hydroxychloroquine Dosing in Intensive Care Unit COVID-19 Patients.

Hydroxychloroquine (HCQ) appears to be a promising treatment for COVID-19. However, all ongoing clinical trials with HCQ use different dosing regimens, resulting in various concentrations. Pharmacokinetic studies are therefore needed to define the optimal dosing regimen.

Three-dimensional quantitative MRI of aerosolized gadolinium-based nanoparticles and contrast agents in isolated ventilated porcine lungs.

PURPOSE: The objective of this study is to evaluate the suitability and performance of ultra-short echo time (UTE) sequences for imaging and quantifying the deposition of nebulized MRI contrast agents in human-sized lungs. METHODS: Nebulization of clinically used contrast agent or gadolinium-based nanoparticles were performed using a commercial jet nebulizer in isolated and ventilated porcine lungs connected to a 3D-printed human upper airways replica. MR images of isolated lungs were acquired on a 3T clinical MR scanner using 3D UTE sequences at different flip angles. RESULTS: 3D acquisitions with isotropic millimetric resolution were obtained in less than 4 min. Images exhibit homogeneous and large MR signal enhancement (above 200%) following nebulization of both types of aerosols. Deposition of aerosol down to the level of the bronchi of secondary lobules was visualized. T1 values and the concentration of nanoparticles obtained by MRI were found to correlate with the amount of nebulized gadolinium3+ ions. CONCLUSION: The distribution of aerosolized gadolinium-based contrast agent or nanoparticles can be visualized and quantified using UTE MRI in large animal ventilated lung model on a clinical MRI scanner. This protocol can be used for assessing and quantifying aerosol regional deposition with high spatial resolution (1 mm 3D isotropic) without ionizing radiation and could be applied in the future for diagnostic or therapeutic applications in patients.

Development of an ex vivo respiratory pediatric model of bronchopulmonary dysplasia for aerosol deposition studies.

Ethical restrictions are limitations of in vivo inhalation studies, on humans and animal models. Thus, in vitro or ex vivo anatomical models offer an interesting alternative if limitations are clearly identified and if extrapolation to human is made with caution. This work aimed to develop an ex vivo infant-like respiratory model of bronchopulmonary dysplasia easy to use, reliable and relevant compared to in vivo infant data. This model is composed of a 3D-printed head connected to a sealed enclosure containing a leporine thorax. Physiological data and pleural-mimicking depressions were measured for chosen respiratory rates. Homogeneity of ventilation was assessed by 81mkrypton scintigraphies. Regional radioaerosol deposition was quantified with 99mtechnetium-diethylene triamine pentaacetic acid after jet nebulization. Tidal volumes values are ranged from 33.16 ± 7.37 to 37.44 ± 7.43 mL and compliance values from 1.78 ± 0.65 to 1.85 ± 0.99 mL/cmH2O. Ventilation scintigraphies showed a homogenous ventilation with asymmetric repartition: 56.94% ± 9.4% in right lung and 42.83% ± 9.36 in left lung. Regional aerosol deposition in lungs exerted 2.60% ± 2.24% of initial load of radioactivity. To conclude the anatomical model satisfactorily mimic a 3-months old BPD-suffering bronchopulmonary dysplasia and can be an interesting tool for aerosol regional deposition studies.

Deposition pattern of aerosolized Legionella using an ex vivo human-porcine respiratory model.

Legionella are bacteria responsible for severe lung pathologies. However how they enter and are deposited within the respiratory tract remains poorly documented. Data using animal testing led to the establishment of mathematical models allowing the estimation of aerosol dispersion risks. But direct extrapolation to humans is questionable and experimental models more physiologically representative of the inhalation route are welcome. The aim of this study was to develop a model as close as possible to the human anatomy and physiology allowing determining the deposition pattern of aerosolized Legionella while limiting in vivo experiments. To that purpose, we adapted the chimeric respiratory tract model we previously developed. This original model consisted of a replica of the human upper respiratory airways made by additive manufacturing connected to ex vivo porcine lungs ventilated by passive expansion, as for humans in physiological conditions. These experiments didn't imply specific animal sacrifices as pigs were bred for human consumption and lungs were considered as wastes by the slaughterhouse. Fluorescent Legionella were aerosolized and visualized using Cellvizio® Lab (probe-based confocal fluorescence microscope). Legionella were found in the whole respiratory tract. Broncho-alveolar lavages were also performed and the amount of Legionella reaching the thoracic region was quantified by culture and qPCR. Legionella were found preferentially in the left upper lobe compared to the right lower lobe. To our knowledge, it is the first time that experiments mimicking so closely human exposure by inhalation are performed while limiting animal experiments and providing a model for further Legionella infectious risk assessment.

Acute kidney injury in the ICU: from injury to recovery: reports from the 5th Paris International Conference.

The French Intensive Care Society organized its yearly Paris International Conference in intensive care on June 18-19, 2015. The main purpose of this meeting is to gather the best experts in the field in order to provide the highest quality update on a chosen topic. In 2015, the selected theme was: "Acute Renal Failure in the ICU: from injury to recovery." The conference program covered multiple aspects of renal failure, including epidemiology, diagnosis, treatment and kidney support system, prognosis and recovery together with acute renal failure in specific settings. The present report provides a summary of every presentation including the key message and references and is structured in eight sections: (a) diagnosis and evaluation, (b) old and new diagnosis tools,

Development of an ex vivo human-porcine respiratory model for preclinical studies.

Anatomical models to study aerosol delivery impose huge limitations and extrapolation to humans remains controversial. This study aimed to develop and validate an ex vivo human-like respiratory tract model easy to use and relevant to compare to in vivo human data. A human plastinated head is connected to an ex vivo porcine pulmonary tract ventilated artificially by passive expansion. A physiological study measures "pleural" depressions, tidal volumes, and minute ventilation for the respiratory rates chosen (10, 15, and 20 per minute) with three inspiratory/expiratory ratios (1/1, 1/2, and 1/3). Scintigraphy with 81mKrypton assesses the homogeneity of the ventilation. Forty different experiments were set for validation, with 36 (90%) ventilating successfully. At a respiratory rate of 15/minute with inspiratory/expiratory ratio of 1/2, the tidal volume average was 824 mL (standard deviation, 207 mL). The scintigraphy performed on 16 ex vivo models (44.4%), showed homogenous ventilation with great similarity to human physiological studies. Ratio of the peripheral to central count rates were equally correlated with human data published in the literature. This new model, combining research feasibility and human physiology likeness, provides a realistic approach to human inhalation and therefore can be an interesting tool in aerosol regional deposition studies.

Acute respiratory distress syndrome mimics: the role of lung biopsy.

PURPOSE OF REVIEW: Acute respiratory distress syndrome (ARDS) mimics is a condition looking like ARDS but that does not fulfill every criterion according to the recent Berlin definition. The purpose of this review is to better delineate ARDS mimics, to discuss why the complete diagnosis of ARDS is important, and to make a brief overview on the role of open lung biopsy in this setting. RECENT FINDINGS: Recent autopsy and lung biopsy data from ARDS patients compared lung histologic findings with the new Berlin definition of ARDS. Among them, there are some limited data about two niches, namely open lung biopsy and ARDS mimics suggesting that lung histology is important for making the diagnosis and offering the accurate management. This includes specific new treatments or stopping some medications toxic to the lung. Finally, ARDS with diffuse alveolar damage could be a specific subphenotype of ARDS with poor prognosis. SUMMARY: An ARDS mimic enhances the need of making ARDS diagnosis as comprehensive as possible. In some limited cases, open lung biopsy in skilled hands may have implications for management.

Outcomes in adult critically ill cancer patients with and without neutropenia: a systematic review and meta-analysis of the Groupe de Recherche en Réanimation Respiratoire du patient d'Onco-Hématologie (GRRR-OH).

PURPOSE: Whether neutropenia has an impact on the mortality of critically ill cancer patients remains controversial, yet it is widely used as an admission criterion and prognostic factor. METHODS: Systematic review and meta-analysis. Studies on adult cancer patients and intensive care units were searched on PubMed and Cochrane databases (2005-2015). Summary estimates of mortality risk differences were calculated using the random-effects model. RESULTS: Among the 1,528 citations identified, 38 studies reporting on 6,054 patients (2,097 neutropenic patients) were included. Median mortality across the studies was 54% [45-64], with unadjusted mortality in neutropenic and non-neutropenic critically ill patients of 60% [53-74] and 47% [41-68], respectively. Overall, neutropenia was associated with a 10% increased mortality risk (6%-14%; I² = 50%). The admission period was not associated with how neutropenia affected mortality. Mortality significantly dropped throughout the study decade [-11% (-13.5 to -8.4)]. This mortality drop was observed in non-neutropenic patients [-12.1% (-15.2 to -9.0)] but not in neutropenic patients [-3.8% (-8.1 to +5.6)].Sensitivity analyses disclosed no differences in underlying malignancy, mechanical ventilation use, or Granulocyte-colony stimulating factor use. Seven studies allowed the adjustment of severity results (1,350 patients). Although pooled risk difference estimates were similar to non-adjusted results, there was no significant impact of neutropenia on mortality (risk difference of mortality, 9%; 95% CI, -15 to +33). CONCLUSION: Although the unadjusted mortality of neutropenic patients was 11% higher, this effect disappeared when adjusted for severity. Therefore, when cancer patients become critically ill, neutropenia cannot be considered as a decision-making criterion.

Acetaminophen-Induced Changes in Systemic Blood Pressure in Critically Ill Patients: Results of a Multicenter Cohort Study.

OBJECTIVES: We sought to assess the incidence of acetaminophen-induced hypotension. Our secondary objectives were to describe systemic hemodynamic changes and factors associated with this complication. DESIGN: Prospective observational study. SETTING: Three ICUs. PATIENTS: Adult patients requiring IV acetaminophen infusion. Arterial pressure was monitored via an arterial catheter for 3 hours. Hypotension was defined as a decrease in the mean arterial pressure of greater than or equal to 15% compared with the baseline. RESULTS: Overall, 160 patients were included in this study. Eighty-three patients (51.9%) experienced acetaminophen-induced hypotension according to our definition. In patients with acetaminophen-induced hypotension, the nadir mean arterial pressure was 64 mm Hg (95% CI, 54-74). Hypotension was observed 30 minutes (95% CI, 15-71) after acetaminophen infusion. Changes in mean arterial pressure were closely correlated with decreases in the diastolic arterial pressure (r = 0.92) and to a lesser extent with changes in the pulse pressure (r = 0.18) and heart rate (r = 0.09). Changes in the body temperature were not correlated with changes in mean arterial pressure (r = 0.0002; p = 0.85). None of the patients' baseline characteristics (shock, use of angiotensin-converting enzyme inhibitor/angiotensin II receptor blockers, lactates, renal replacement therapy, chronic heart disease, and indication for acetaminophen infusion) or clinically relevant characteristics (baseline severity according to Logistic Organ Dysfunction score, need for vasopressors, use of antihypertensive agents, need for mechanical ventilation, or changes in the body temperature) were independently associated with acetaminophen-induced hypotension. Among patients with acetaminophen-induced hypotension, 29 (34.9%) required therapeutic intervention. CONCLUSIONS: Half of the patients who received IV injections of acetaminophen developed hypotension, and up to one third of the observed episodes necessitated therapeutic intervention. Adequately powered randomized studies are needed to confirm our findings, provide an accurate estimation of the consequences of acetaminophen-induced hypotension, and assess the pathophysiologic mechanisms involved.

Micron-sized and submicron-sized aerosol deposition in a new ex vivo preclinical model.

BACKGROUND: The knowledge of where particles deposit in the respiratory tract is crucial for understanding the health effects associated with inhaled drug particles. METHOD: An ex vivo study was conducted to assess regional deposition patterns (thoracic vs. extrathoracic) of radioactive polydisperse aerosols with different size ranges [0.15 µm-0.5 µm], [0.25 µm-1 µm] and [1 µm-9 µm]. SPECT/CT analyses were performed complementary in order to assess more precisely the regional deposition of aerosols within the pulmonary tract. Experiments were set using an original respiratory tract model composed of a human plastinated head connected to an ex vivo porcine pulmonary tract. The model was ventilated by passive expansion, simulating pleural depressions. Aerosol was administered during nasal breathing. RESULTS: Planar scintigraphies allowed to calculate the deposited aerosol fractions for particles in the three size ranges from sub-micron to micron The deposited fractions obtained, for thoracic vs. extra-thoracic regions respectively, were 89 ± 4 % vs. 11 ± 4 % for [0.15 µm-0.5 µm], 78 ± 5 % vs. 22 ± 5 % for [0.25 µm-1 µm] and 35 ± 11 % vs.65 ± 11 % for [1 µm-9 µm]. CONCLUSION: Results obtained with this new ex vivo respiratory tract model are in good agreement with the in vivo data obtained in studies with baboons and humans.

Transient and Persistent Acute Kidney Injury and the Risk of Hospital Mortality in Critically Ill Patients: Results of a Multicenter Cohort Study.

OBJECTIVE: To assess the prognostic impact of transient and persistent acute kidney injury in critically ill patients. DESIGN: Retrospective analysis of prospectively collected patient data SETTING: : Six hospital ICUs. PATIENTS: Critically-ill patients with ICU stay longer than three days. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Assessment of hospital survival with respect to acute kidney injury duration. A total of 447 patients were included in this study, including 283 patients (63.3%) with an acute kidney injury at admission (175 and 108 patients with persistent and transient acute kidney injury, respectively). Patients with persistent acute kidney injury more frequently had stage 3 acute kidney injury (42.9% vs 30.6%; p = 0.04). Hospital survival was 76.2% (n = 125) in patients without acute kidney injury, 70.4% (n = 76) in patients with transient acute kidney injury, and 61.1% (n = 107) in patients with persistent acute kidney injury. After adjustment for confounding factors, the factors associated with lower hospital survival were the need for vasopressors (odds ratio, 0.65; 95% CI, 0.43-0.98) and the presence of persistent acute kidney injury (odds ratio, 0.58; 95% CI, 0.36-0.95). When included in the final model, stage 3 acute kidney injury was independently associated with a lower hospital survival (odds ratio, 0.83; 95% CI, 0.70-0.98), and persistent acute kidney injury was no longer associated with outcome. CONCLUSION: Two thirds of the critically ill patients with acute kidney injury have persistent acute kidney injury. Although mortality increased progressively with the duration of acute kidney injury, we found no independent association between this duration and patient outcome when the acute kidney injury severity is taken into account. Our results suggest that the classical "prerenal acute kidney injury" and "acute tubular necrosis" paradigm might be of limited interest from a pathophysiological or prognostic point of view.