Arnaud Mari

Usefulness of Cardiothoracic Chest Ultrasound in the Management of Acute Respiratory Failure in Critical Care Practice

BACKGROUND This study investigated the clinical relevance of early general chest ultrasonography (ie, heart and lung recordings) in patients in the ICU with acute respiratory failure (ARF). METHODS We prospectively compared this diagnostic approach (ultrasound) to a routine evaluation established from clinical, radiologic, and biologic data (standard). Subjects were patients consecutively admitted to the ICU of a university teaching hospital during a 1-year period. Inclusion criteria were age ≥ 18 years and the presence of severe ARF criteria to justify ICU admission. We compared the diagnostic approaches and the final diagnosis determined by a panel of experts. RESULTS Seventy-eight patients were included (age, 70 ± 18 years; sex ratio, 1). Three patients given two or more simultaneous diagnoses were subsequently excluded. The ultrasound approach was more accurate than the standard approach (83% vs 63%, respectively; P < .02). Receiver operating characteristic curve analysis showed greater diagnostic performance of ultrasound in cases of pneumonia (standard, 0.74 ± 0.12; ultrasound, 0.87 ± 0.14; P < .02), acute hemodynamic pulmonary edema (standard, 0.79 ± 0.11; ultrasound, 0.93 ± 0.08; P < .007), decompensated COPD (standard, 0.8 ± 0.09; ultrasound, 0.92 ± 0.15; P < .05), and pulmonary embolism (standard, 0.65 ± 0.12; ultrasound, 0.81 ± 0.17; P < .04). Furthermore, we found that the use of ultrasound data could have significantly improved the initial treatment. CONCLUSIONS The use of cardiothoracic ultrasound appears to be an attractive complementary diagnostic tool and seems able to contribute to an early therapeutic decision based on reproducible physiopathologic data.

Clinical relevance of pulse pressure variations for predicting fluid responsiveness in mechanically ventilated intensive care unit patients: the grey zone approach

IntroductionPulse pressure variation (PPV) has been shown to predict fluid responsiveness in ventilated intensive care unit (ICU) patients. The present study was aimed at assessing the diagnostic accuracy of PPV for prediction of fluid responsiveness by using the grey zone approach in a large population.MethodsThe study pooled data of 556 patients from nine French ICUs. Hemodynamic (PPV, central venous pressure (CVP) and cardiac output) and ventilator variables were recorded. Responders were defined as patients increasing their stroke volume more than or equal to 15% after fluid challenge. The receiver operating characteristic (ROC) curve and grey zone were defined for PPV. The grey zone was evaluated according to the risk of fluid infusion in hypoxemic patients.ResultsFluid challenge led to increased stroke volume more than or equal to 15% in 267 patients (48%). The areas under the ROC curve of PPV and CVP were 0.73 (95% confidence interval (CI): 0.68 to 0.77) and 0.64 (95% CI 0.59 to 0.70), respectively (P <0.001). A grey zone of 4 to 17% (62% of patients) was found for PPV. A tidal volume more than or equal to 8 ml.kg-1 and a driving pressure (plateau pressure - PEEP) more than 20 cmH2O significantly improved the area under the ROC curve for PPV. When taking into account the risk of fluid infusion, the grey zone for PPV was 2 to 13%.ConclusionsIn ventilated ICU patients, PPV values between 4 and 17%, encountered in 62% patients exhibiting validity prerequisites, did not predict fluid responsiveness.

Integrated Use of Bedside Lung Ultrasound and Echocardiography in Acute Respiratory Failure : A Prospective Observational Study in ICU

BACKGROUND It has been suggested that the complementary use of echocardiography could improve the diagnostic accuracy of lung ultrasonography (LUS) in patients with acute respiratory failure (ARF). Nevertheless, the additional diagnostic value of echocardiographic data when coupled with LUS is still debated in this setting. The aim of the current study was to compare the diagnostic accuracy of LUS and an integrative cardiopulmonary ultrasound approach (thoracic ultrasonography [TUS]) in patients with ARF. METHODS We prospectively recruited patients consecutively admitted for ARF to the ICU of a university teaching hospital over a 12-month period. Inclusion criteria were age ≥ 18 years and the presence of criteria for severe ARF justifying ICU admission. We compared both LUS and TUS approaches and the final diagnosis determined by a panel of experts using machine learning methods to improve the accuracy of the final diagnostic classifiers. RESULTS One hundred thirty-six patients were included (age, 68 ± 15 years; sex ratio, 1). A three-dimensional partial least squares and multinomial logistic regression model was developed and subsequently tested in an independent sample of patients. Overall, the diagnostic accuracy of TUS was significantly greater than LUS (P < .05, learning and test sample). Comparisons between receiver operating characteristic curves showed that TUS significantly improves the diagnosis of cardiogenic edema (P < .001, learning and test samples), pneumonia (P < .001, learning and test samples), and pulmonary embolism (P < .001, learning sample). CONCLUSIONS This study demonstrated for the first time to our knowledge a significantly better performance of TUS than LUS in the diagnosis of ARF. The value of the TUS approach was particularly important to disambiguate cases of hemodynamic pulmonary edema and pneumonia. We suggest that the bedside use of artificial intelligence methods in this setting could pave the way for the development of new clinically relevant integrative diagnostic models.

Combined Thoracic Ultrasound Assessment during a Successful Weaning Trial Predicts Postextubation Distress

Background: Recent studies suggest that isolated sonographic assessment of the respiratory, cardiac, or neuromuscular functions in mechanically ventilated patients may assist in identifying patients at risk of postextubation distress. The aim of the present study was to prospectively investigate the value of an integrated thoracic ultrasound evaluation, encompassing bedside respiratory, cardiac, and diaphragm sonographic data in predicting postextubation distress. Methods: Longitudinal ultrasound data from 136 patients who were extubated after passing a trial of pressure support ventilation were measured immediately after the start and at the end of this trial. In case of postextubation distress (31 of 136 patients), an additional combined ultrasound assessment was performed while the patient was still in acute respiratory failure. We applied machine-learning methods to improve the accuracy of the related predictive assessments. Results: Overall, integrated thoracic ultrasound models accurately predict postextubation distress when applied to thoracic ultrasound data immediately recorded before the start and at the end of the trial of pressure support ventilation (learning sample area under the curve: start, 0.921; end, 0.951; test sample area under the curve: start, 0.972; end, 0.920). Among integrated thoracic ultrasound data, the recognition of lung interstitial edema and the increased telediastolic left ventricular pressure were the most relevant predictive factors. In addition, the use of thoracic ultrasound appeared to be highly accurate in identifying the causes of postextubation distress. Conclusions: The decision to attempt extubation could be significantly assisted by an integrative, dynamic, and fully bedside ultrasonographic assessment of cardiac, lung, and diaphragm functions.

The elusive task of biomarkers of renal injury

Neutrophil gelatinase-associated lipocalin (NGAL) is one of the most promising candidate biomarkers of renal injury, with expression in renal tissue increasing dramatically after ischemia-reperfusion injury but not in the case of pure pre-renal failure. In a recent issue of Critical Care, Di Somma and colleagues reported that NGAL could improve the classification of acute kidney injury compared with clinical assessment and showed that NGAL was associated with poor prognosis. NGAL may therefore carry different information than biomarkers of renal function. This study finally provides additional evidence for the highly complex relationship between renal function and renal injury.

Hemodynamic Assessment of Patients With Septic Shock Using Transpulmonary Thermodilution and Critical Care Echocardiography: A Comparative Study

Background To assess the agreement between transpulmonary thermodilution (TPT) and critical care echocardiography (CCE) in ventilated patients with septic shock. Methods Ventilated patients in sinus rhythm requiring advanced hemodynamic assessment for septic shock were included in this prospective multicenter descriptive study. Patients were assessed successively using TPT and CCE in random order. Data were interpreted independently at bedside by two investigators who proposed therapeutic changes on the basis of predefined algorithms. TPT and CCE hemodynamic assessments were reviewed offline by two independent experts who identified potential sources of discrepant results by consensus. Lactate clearance and outcome were studied. Results A total of 137 patients were studied (71 men; age, 61 ± 15 years; Simplified Acute Physiologic Score, 58 ± 18; Sequential Organ Failure Assessment, 10 ± 3). TPT and CCE interpretations at bedside were concordant in 87/132 patients (66%) without acute cor pulmonale (ACP), resulting in a moderate agreement (kappa, 0.48; 95% CI, 0.37‐0.60). Experts’ adjudications were concordant in 100/129 patients without ACP (77.5%), resulting in a good intertechnique agreement (kappa, 0.66; 95% CI, 0.55‐0.77). In addition to ACP (n = 8), CCE depicted a potential source of TPT inaccuracy in 8/29 patients (28%). Lactate clearance at H6 was similar irrespective of the concordance of online interpretations of TPT and CCE (55/84 [65%] vs 32/45 [71%], P = .55). ICU and day 28 mortality rates were similar between patients with concordant and discordant interpretations (29/87 [36%] vs 13/45 [29%], P = .60; and 31/87 [36%] vs 16/45 [36%], P = .99, respectively). Conclusions Agreement between TPT and CCE was moderate when interpreted at bedside and good when adjudicated offline by experts, but without impact on lactate clearance and mortality.

Oxygen challenge test in septic shock patients: prognostic value and influence of respiratory status.

ABSTRACT Transcutaneous oxygen pressure (PtcO2) value in response to an increase of FiO2 or oxygen challenge test (OCT) in ventilated patients has been reported to be related to peripheral perfusion and outcome during septic shock. However, patients with sepsis-related acute respiratory distress syndrome could demonstrate compromised arterial oxygenation with OCT impairment decoupled to circulatory failure. The aims of this study were to confirm the prognostic value of OCT and to explore the influence of respiratory status on OCT results. This was a prospective study set in an intensive care unit of a tertiary teaching hospital. Fifty-six mechanically ventilated patients with septic shock criteria were studied. Transcutaneous oxygen pressure was measured at baseline and after OCT, at intensive care unit admittance (T0), and 24 h later (T24). Survival at day 28 and hemodynamic and respiratory parameters were analyzed and compared according to outcome and respiratory status. Central hemodynamic parameters or static transcutaneous data did not differ between survivors and nonsurvivors at enrollment. The OCT was statistically different at T24 according to outcome (P < 0.001), but sensitivity was low (53%). Moreover, patients with low OCT results at T24 exhibited more severe respiratory failure (P < 0.01). The OCT at T24 is related to outcome but is influenced by the severity of respiratory failure. Our results suggest considering with caution hemodynamic management based on OCT in septic shock patients with altered pulmonary function.

Oxalate nephropathy following vitamin C intake within intensive care unit

OBJECTIVE To report a case of acute oxalate nephropathy related to vitamin C intake within the intensive care unit (ICU). DESIGN Case report. SETTING ICU and nephrology department of a French university hospital. PATIENT A 57-year-old woman with septic shock related to Legionella pneumophila pneumonia complicated by acute respiratory distress syndrome and acute kidney injury who required renal replacement therapy for 75 days. MEASUREMENTS AND MAIN RESULTS A renal biopsy was performed on day 72 because of persistent anuria and because the patient showed characteristic features of severe acute oxalate nephropathy. The only cause identified was vitamin C intake received during hospitalization within the ICU (~ 30 g over 2.5 months). At month 6 after ICU admission, estimated glomerular filtration rate was 24 mL/min/1.73m2. CONCLUSION Compelling evidence obtained from in-vitro and animal studies suggest that vitamin C, a circulating antioxidant, may be a valuable adjunctive therapy in critically-ill patients. Data from humans are more conflicting. Oxalate, a well-known metabolite of vitamin C, is excreted by the kidneys and can exert a toxic effect on epithelial cells and causes direct tubular damage, and/or it can crystallize within the tubular lumen. This case highlights an under-recognized secondary adverse event from vitamin C given to critically-ill patients. The use of high-dose vitamin C should be prescribed with caution in this population.
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Diagnostic and management of life-threatening Adult-Onset Still Disease: a French nationwide multicenter study and systematic literature review

BackgroundAdult-onset Still disease (AOSD) is a rare systemic inflammatory disorder. A few patients develop organ complications that can be life-threatening. Our objectives were to describe the disease course and phenotype of life-threatening AOSD, including response to therapy and long-term outcome.MethodsA multicenter case series of intensive care medicine (ICU) patients with life-threatening AOSD and a systematic literature review.ResultsTwenty patients were included. ICU admission mostly occurred at disease onset (90%). Disease manifestations included fever (100%), sore throat (65%), skin rash (65%), and arthromyalgia (55%). Serum ferritin was markedly high (median: 29,110 ng/mL). Acute respiratory failure, shock and multiple organ failure occurred in 15 (75%), 10 (50%), and 7 (35%) cases, respectively. Hemophagocytosis was demonstrated in eight cases. Two patients died. Treatment delay was significant. All patients received corticosteroids. Response rate was 50%. As second-line, intravenous immunoglobulins were ineffective. Anakinra was highly effective. After ICU discharge, most patients required additional treatment. Literature analysis included 79 cases of AOSD with organ manifestations, which mainly included reactive hemophagocytic syndrome (42%), acute respiratory failure (34%), and cardiac complications (23%). Response rate to corticosteroids was 68%. Response rates to IVIgs, cyclosporin, and anakinra were 50%, 80%, and 100%, respectively.ConclusionsAOSD should be recognized as a rare cause of sepsis mimic in patients with fever of unknown origin admitted to the ICU. The diagnosis relies on a few simple clinical clues. Early intensive treatment may be discussed. IVIgs should be abandoned. Long-term prognosis is favorable.

Massive hyperhomocysteinaemia as a complication of nitrous oxide inhalation.

Here, we report two cases of venous thromboembolic events associated with massive hyperhomocysteinaemia (7 to 10 fold the normal values) induced by a prolonged use of inhaled 50% nitrous oxide/oxygen premix during sickle-cell disease (SCD)-related acute pain disease. Given that SCD patients are at risk of deep vein thrombosis, we suggest that inhaled nitrous oxide should be use with caution in these patients and serum level of homocysteine should be monitored. Inhaled 50% nitrous oxide/oxygen premix is a potent analgesic with amnesic properties and a safe profile linked to its rapid onset and elimination. Its main complication is megaloblastic anaemia that occurs after long exposures (>24 h) [1]. Here, we present two cases of massive hyperhomocysteinaemia after prolonged but intermittent therapeutic use of inhaled nitrous oxide. Two women (36 and 30-years-old), followed for SCD and receiving hydroxyurea because of recurrent vaso-occlusive disease, were hospitalized in the intensive care unit for severe acute pain disease requiring multimodal analgesia including non-steroidal anti-inflammatory drugs, tramadol, nefopan chlohydrate, paracetamol, pregabalin, ketamine and intravenous oxycodone. Because of refractory pain, inhaled 50% nitrous oxide/oxygen premix was given (10 to 20 min every 4 to 6 h for 7 to 9 days) allowing a substantial decrease of the opioid use. Neither of these patients had a previous history of venous thromboembolism and both received prophylaxis including a low molecular weight heparin. In both patients, deep vein thrombosis was recognized during their hospital stay. In one of them, thrombosis progressed despite curative anticoagulation with low molecular weight heparin (enoxaparin). In the second, iliac occlusive thrombosis (phlegmasia caerulea dolens) developed and required in situ intravenous thrombolysis. In both, no oral contraception was used. Apart from the intrinsic risk of venous thromboembolism in SCD patients [2], thrombophilia screening identified a massive hyperhomocysteinaemia (153 and 99 μmol l, respectively; normal 5–15 μmol l). Concomitantly, serum folic acid and vitamin B12 were normal. After inhaled nitrous oxide withdrawal and oral folic acid supplementation, serum homocysteine level normalized within 3 weeks suggesting the lack of an underlying inherited hyperhomocysteinaemia. Nitrous oxide inhibits methionine synthetase and thus potentially leads to mild hyperhomocysteinaemia (<40 μmol l) with uncertain clinical significance when used as an anaesthetic agent for less than 3 h [3, 4]. In our patients, the cumulative time of nitrous oxide exposure was 10 to 15 h, spread over 7 days, and nitrous oxide was the only factor that may have induced hyperhomocysteinaemia. These cases highlight the potential for transient massive hyperhomocysteinaemia, an independent risk factor for venous thrombosis and cardiac morbidity potentially through causing endothelial dysfunction and procoagulation [5], after prolonged therapeutic use of inhaled 50% nitrous oxide/oxygen premix. In patients with sickle cell disease, other adverse events related to a direct effect of the prolonged use of this premix have also been described, including severe neuropathy [6]. Thus, we consider that prolonged use of inhaled 50% nitrous oxide/oxygen premix should be used with caution in patients with SCD, a condition at risk of venous thrombosis, and that homocysteinaemia should be monitored in cases of prolonged use.