Introduction
Peripheral veno-arterial extracorporeal membrane oxygenation (VA ECMO) creates a retrograde flow along the aorta competing with the left ventricle (LV) in the so-called ‘mixing zone’ ...(MZ). Detecting it is essential to understand which of the LV or the ECMO flow perfuses the upper body – particularly the brain and the coronary arteries – in case of differential hypoxemia (DH).
Methods
We described a mock circulation loop (MCL) that enabled experimental research on DH. We recreated the three clinical situations relevant to clinicians: where the brain is either totally perfused by the ECMO or the LV or both. In a second step, we used this model to investigate two scenarios to diagnose DH: (i) pulse pressure and (ii) thermodilution via injection of cold saline in the ECMO circuit.
Results
The presented MCL was able to reproduce the three relevant mixing zones within the aortic arch, thus allowing to study DH. Pulse pressure was unable to detect location of the MZ. However, the thermodilution method was able to detect whether the brain was totally perfused by the ECMO or not.
Conclusion
We validated an in-vitro differential hypoxemia model of cardiogenic shock supported by VA ECMO. This MCL could be used as an alternative to animal studies for research scenarios.
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NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
Abstract
Background
Current practices regarding tracheostomy in patients treated with extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome are unknown. Our objectives ...were to assess the prevalence and the association between the timing of tracheostomy (during or after ECMO weaning) and related complications, sedative, and analgesic use.
Methods
International, multicenter, retrospective study in four large volume ECMO centers during a 9-year period.
Results
Of the 1,168 patients treated with ECMO for severe ARDS (age 48 ± 16 years, 76% male, SAPS II score 51 ± 18) during the enrollment period, 353 (30%) and 177 (15%) underwent tracheostomy placement during or after ECMO, respectively. Severe complications were uncommon in both groups. Local bleeding within 24 h of tracheostomy was four times more frequent during ECMO (25 vs 7% after ECMO,
p
< 0.01). Cumulative sedative consumption decreased more rapidly after the procedure with sedative doses almost negligible 48–72 h later, when tracheostomy was performed after ECMO decannulation (
p
< 0.01). A significantly increased level of consciousness was observed within 72 h after tracheostomy in the “after ECMO” group, whereas it was unchanged in the “during-ECMO” group.
Conclusion
In contrast to patients undergoing tracheostomy after ECMO decannulation, tracheostomy during ECMO was neither associated with a decrease in sedation and analgesia levels nor with an increase in the level of consciousness. This finding together with a higher risk of local bleeding in the days following the procedure reinforces the need for a case-by-case discussion on the balance between risks and benefits of tracheotomy when performed during ECMO.
Tracheostomy has been proposed as an option to help organize the healthcare system to face the unprecedented number of patients hospitalized for a COVID-19-related acute respiratory distress syndrome ...(ARDS) in intensive care units (ICU). It is, however, considered a particularly high-risk procedure for contamination. This paper aims to provide our experience in performing tracheostomies on COVID-19 critically ill patients during the pandemic and its long-term local complications.
We performed a retrospective analysis of prospectively collected data of patients tracheostomized for a COVID-19-related ARDS in two university hospitals in the Paris region between January 27th (date of first COVID-19 admission) and May 18th, 2020 (date of last tracheostomy performed). We focused on tracheostomy technique (percutaneous versus surgical), timing (early versus late) and late complications.
Forty-eight tracheostomies were performed with an equal division between surgical and percutaneous techniques. There was no difference in patients' characteristics between surgical and percutaneous groups. Tracheostomy was performed after a median of 17 12-22 days of mechanical ventilation (MV), with 10 patients in the "early" group (≤ day 10) and 38 patients in the "late" group (> day 10). Survivors required MV for a median of 32 22-41 days and were ultimately decannulated with a median of 21 15-34 days spent on cannula. Patients in the early group had shorter ICU and hospital stays (respectively 15 12-19 versus 35 25-47 days; p = 0.002, and 21 16-28 versus 54 35-72 days; p = 0.002) and spent less time on MV (respectively 17 14-20 and 35 27-43 days; p<0.001). Interestingly, patients in the percutaneous group had shorter hospital and rehabilitation center stays (respectively 44 34-81 versus 92 61-118 days; p = 0.012, and 24 11-38 versus 45 22-71 days; p = 0.045). Of the 30 (67%) patients examined by a head and neck surgeon, 17 (57%) had complications with unilateral laryngeal palsy (n = 5) being the most prevalent.
Tracheostomy seems to be a safe procedure that could help ICU organization by delegating work to a separate team and favoring patient turnover by allowing faster transfer to step-down units. Following guidelines alone was found sufficient to prevent the risk of aerosolization and contamination of healthcare professionals.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Necrotizing soft-tissue infection (NSTI) is a life-threatening pathology that often requires management in intensive care unit (ICU). Therapies consist of early diagnosis, adequate surgical source ...control, and antimicrobial therapy. Whereas guidelines underline the need for appropriate routine microbiological cultures before starting antimicrobial therapy in patients with suspected sepsis or septic shock, delaying adequate therapy also strongly increases mortality. The aim of the present study was to compare the characteristics and outcomes of patients hospitalized in ICU for NSTI according to their antimicrobial therapy exposure > 24 h before surgery (called the exposed group) or not (called the unexposed group) before surgical microbiological sampling. We retrospectively included 100 consecutive patients admitted for severe NSTI. The exposed group consisted of 23(23%) patients, while 77(77%) patients belonged to the unexposed group. The demographic and underlying disease conditions were similar between the two groups. Microbiological cultures of surgical samples were positive in 84 patients and negative in 16 patients, including 3/23 (13%) patients and 13/77 (17%) patients in the exposed and unexposed groups, respectively (
p
= 0.70). The distribution of microorganisms was comparable between the two groups. The main antimicrobial regimens for empiric therapy were also similar, and the proportions of adequacy were comparable (
n
= 60 (84.5%) in the unexposed group vs.
n
= 19 (86.4%) in the exposed group,
p
= 0.482). ICU and hospital lengths of stay and mortality rates were similar between the two groups. In conclusion, in a population of severe ICU NSTI patients, antibiotic exposure before sampling did not impact either culture sample positivity or microbiological findings.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Purpose
Flexible fiberoptic bronchoscopy is frequently used in intensive care unit, but is a source of discomfort, dyspnea and anxiety for patients. Our objective was to assess the feasibility and ...tolerance of a sedation using remifentanil target-controlled infusion, to perform fiberoptic bronchoscopy in awake ICU patients.
Materials, patients and methods
This monocentric, prospective observational study was conducted in awake patients requiring fiberoptic bronchoscopy. In accordance with usual practices in our center, remifentanil target-controlled infusion was used under close monitoring and adapted to the patient’s reactions. The primary objective was the rate of successful procedures without additional analgesia or anesthesia. The secondary objectives were clinical tolerance and the comfort of patients (graded from “very uncomfortable” to “very comfortable”) and operators (numeric scale from 0 to 10) during the procedure.
Results
From May 2014 to December 2015, 72 patients were included. Most of them (69%) were hypoxemic and admitted for acute respiratory failure. No additional medication was needed in 96% of the patients. No severe side-effects occurred. Seventy-eight percent of patients described the procedure as “comfortable or very comfortable”. Physicians rated their comfort with a median IQR score of 9 8–10.
Conclusion
Remifentanil target-controlled infusion administered to perform awake fiberoptic bronchoscopy in critically ill patients is feasible without requirement of additional analgesics or sedative drugs. Clinical tolerance as well as patients’ and operators’ comfort were good to excellent. This technique could benefit patients’ experience.
Differential hypoxaemia (DH) is common in patients supported by femoral veno-arterial extracorporeal membrane oxygenation (V-A ECMO) and can cause cerebral hypoxaemia. To date, no models have studied ...the direct impact of flow on cerebral damage. We investigated the impact of V-A ECMO flow on brain injury in an ovine model of DH. After inducing severe cardiorespiratory failure and providing ECMO support, we randomised six sheep into two groups: low flow (LF) in which ECMO was set at 2.5 L min
ensuring that the brain was entirely perfused by the native heart and lungs, and high flow (HF) in which ECMO was set at 4.5 L min
ensuring that the brain was at least partially perfused by ECMO. We used invasive (oxygenation tension-PbTO
, and cerebral microdialysis) and non-invasive (near infrared spectroscopy-NIRS) neuromonitoring, and euthanised animals after five hours for histological analysis. Cerebral oxygenation was significantly improved in the HF group as shown by higher PbTO
levels (+ 215% vs - 58%, p = 0.043) and NIRS (67 ± 5% vs 49 ± 4%, p = 0.003). The HF group showed significantly less severe brain injury than the LF group in terms of neuronal shrinkage, congestion and perivascular oedema (p < 0.0001). Cerebral microdialysis values in the LF group all reached the pathological thresholds, even though no statistical difference was found between the two groups. Differential hypoxaemia can lead to cerebral damage after only a few hours and mandates a thorough neuromonitoring of patients. An increase in ECMO flow was an effective strategy to reduce such damages.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Refractory cardiogenic shock (CS) often requires veno-arterial extracorporeal membrane oxygenation (VA-ECMO) to sustain end-organ perfusion. Current animal models result in heterogenous cardiac ...injury and frequent episodes of refractory ventricular fibrillation. Thus, we aimed to develop an innovative, clinically relevant, and titratable model of severe cardiopulmonary failure. Six sheep (60 ± 6 kg) were anaesthetized and mechanically ventilated. VA-ECMO was commenced and CS was induced through intramyocardial injections of ethanol. Then, hypoxemic/hypercapnic pulmonary failure was achieved, through substantial decrease in ventilatory support. Echocardiography was used to compute left ventricular fractional area change (LVFAC) and cardiac Troponin I (cTnI) was quantified. After 5 h, the animals were euthanised and the heart was retrieved for histological evaluations. Ethanol (58 ± 23 mL) successfully induced CS in all animals. cTnI levels increased near 5000-fold. CS was confirmed by a drop in systolic blood pressure to 67 ± 14 mmHg, while lactate increased to 4.7 ± 0.9 mmol/L and LVFAC decreased to 16 ± 7%. Myocardial samples corroborated extensive cellular necrosis and inflammatory infiltrates. In conclusion, we present an innovative ovine model of severe cardiopulmonary failure in animals on VA-ECMO. This model could be essential to further characterize CS and develop future treatments.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Rapid diagnostic tests detecting microbial resistance are needed for limiting the duration of inappropriateness of empirical antimicrobial therapy (EAT) in intensive care unit patients, besides ...reducing the use of broad-spectrum antibiotics. We hypothesized that the betaLACTA® test (BLT) could lead to early increase in the adequacy of antimicrobial therapy.
This was a case-control study. Sixty-one patients with BLT-guided adaptation of EAT were prospectively included, and then matched with 61 "controls" having similar infection characteristics (community or hospital-acquired, and source of infection), in whom EAT was conventionally adapted to antibiogram results. Endpoints were to compare the proportion of appropriate (primary endpoint) and optimal (secondary endpoint) antimicrobial therapies with each of the two strategies, once microbiological sample culture results were available.
Characteristics of patients, infections and EAT at inclusion were similar between groups. Nine early escalations of EAT occurred in the BLT-guided adaptation group, reaching 98% appropriateness vs. 77% in the conventional adaptation group (p < 0.01). The BLT reduced the time until escalation of an inappropriate EAT from 50.5 (48-73) to 27 (24-28) hours (p < 0.01). Seventeen early de-escalations occurred in the BLT-guided adaptation group, compared to one in the conventional adaptation group, reducing patients' exposure to broad-spectrum beta-lactam such as carbapenems. In multivariate analysis, use of the BLT was strongly associated with early appropriate (OR = 18 (3.4-333.8), p = 0.006) and optimal (OR = 35.5 (9.6-231.9), p < 0.001) antimicrobial therapies. Safety parameters were similar between groups.
Our study suggests that a BLT-guided adaptation strategy may allow early beta-lactam adaptation from the first 24 hours following the beginning of sepsis management.
Objectives
Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly being used to treat patients with refractory severe heart failure. Large animal models are developed to help ...understand physiology and build translational research projects. In order to better understand those experimental models, we conducted a systematic literature review of animal models combining heart failure and VA-ECMO.
Studies selection
A systematic review was performed using Medline via PubMed, EMBASE, and Web of Science, from January 1996 to January 2019. Animal models combining experimental acute heart failure and ECMO were included. Clinical studies, abstracts, and studies not employing VA-ECMO were excluded.
Data extraction
Following variables were extracted, relating to four key features: (1) study design, (2) animals and their peri-experimental care, (3) heart failure models and characteristics, and (4) ECMO characteristics and management.
Results
Nineteen models of heart failure and VA-ECMO were included in this review. All were performed in large animals, the majority (
n
= 13) in pigs. Acute myocardial infarction (
n
= 11) with left anterior descending coronary ligation (
n
= 9) was the commonest mean of inducing heart failure. Most models employed peripheral VA-ECMO (
n
= 14) with limited reporting.
Conclusion
Among models that combined severe heart failure and VA-ECMO, there is a large heterogeneity in both design and reporting, as well as methods employed for heart failure. There is a need for standardization of reporting and minimum dataset to ensure translational research achieve high-quality standards.
The acute respiratory distress syndrome (ARDS) describes a heterogenous population of patients with acute severe respiratory failure. However, contemporary advances have begun to identify distinct ...sub‐phenotypes that exist within its broader envelope. These sub‐phenotypes have varied outcomes and respond differently to several previously studied interventions. A more precise understanding of their pathobiology and an ability to prospectively identify them, may allow for the development of precision therapies in ARDS. Historically, animal models have played a key role in translational research, although few studies have so far assessed either the ability of animal models to replicate these sub‐phenotypes or investigated the presence of sub‐phenotypes within animal models. Here, in three ovine models of ARDS, using combinations of oleic acid and intravenous, or intratracheal lipopolysaccharide, we investigated the presence of sub‐phenotypes which qualitatively resemble those found in clinical cohorts. Principal Component Analysis and partitional clustering identified two clusters, differentiated by markers of shock, inflammation, and lung injury. This study provides a first exploration of ARDS phenotypes in preclinical models and suggests a methodology for investigating this phenomenon in future studies.
This study provides a first exploration of ARDS phenotypes in preclinical models and suggests a methodology for investigating this phenomenon in future studies
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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