Impact of Isolation Time of COVID-19 Patients in Intensive Care Unit on Healthcare Workers Contamination and Nursing Care Intensity.

Background: The optimal isolation time of COVID-19 patients in intensive care unit (ICU) is debated. We investigated the impact of two different COVID-19 patient isolation time strategies on healthcare workers (HCW) contamination, intensity of nursing care and potential associated adverse events. Methods: We prospectively included all consecutive COVID-19 patients and HCW in our ICU in the first two pandemic waves (March to May 2020 and August to November 2020). Specific isolation measures for COVID-19 patients were released after two negative RT-PCR assays in the first wave and 14 days after the onset of symptoms in the second wave. Contamination of HCW was assessed at the end of each pandemic wave by combining both a RT-PCR assay and a serological test. Results: Overall, 117 COVID-19 patients and 73 HCW were included. Despite an earlier release from isolation after ICU admission in the second than in the first wave [6 (4-8) vs. 15 (11-19) days, p < 0.01], the proportion of HCW with a positive serological test (16 vs. 17%, p = 0.94) or with a positive RT-PCR assay (3 vs. 5%, p = 0.58) was not different between the two waves. Although a lower nurse-to-bed ratio, the intensity of nursing care was higher in the second than in the first wave. A longer isolation time was associated with accidental extubation (OR = 1.18, 95%CI:1.07-1.35, p = 0.005) but neither with ventilator-associated pneumonia nor with dysglycemia. Conclusion: A shorter isolation time of COVID-19 patients in ICU was not associated with higher HCW contamination, while a longer isolation time seemed to be associated with higher accidental extubation.

Characteristics of Cardiac Injury in Critically Ill Patients With Coronavirus Disease 2019.

BACKGROUND: Cardiac injury has been reported in up to 30% of coronavirus disease 2019 (COVID-19) patients. However, cardiac injury is defined mainly by troponin elevation without description of associated structural abnormalities and its time course has not been studied. RESEARCH QUESTION: What are the ECG and echocardiographic abnormalities as well as their time course in critically ill COVID-19 patients? STUDY DESIGN AND METHODS: The cardiac function of 43 consecutive COVID-19 patients admitted to two ICUs was assessed prospectively and repeatedly, combining ECG, cardiac biomarker, and transthoracic echocardiographic analyses from ICU admission to ICU discharge or death or to a maximum follow-up of 14 days. Cardiac injury was defined by troponin elevation and newly diagnosed ECG or echocardiographic abnormalities, or both. RESULTS: At baseline, 49% of patients demonstrated a cardiac injury, and 70% of patients experienced cardiac injury within the first 14 days of ICU stay, with a median time of occurrence of 3 days (range, 0-7 days). The most frequent abnormalities were ECG or echocardiographic signs, or both, of left ventricular (LV) abnormalities (87% of patients with cardiac injury), right ventricular (RV) systolic dysfunction (47%), pericardial effusion (43%), new-onset atrial arrhythmias (33%), LV relaxation impairment (33%), and LV systolic dysfunction (13%). Between baseline and day 14, the incidence of pericardial effusion and of new-onset atrial arrhythmias increased and the incidence of ECG or echocardiographic signs, or both, of LV abnormalities as well as the incidence of LV relaxation impairment remained stable, whereas the incidence of RV and LV systolic dysfunction decreased. INTERPRETATION: Cardiac injury is common and early in critically ill COVID-19 patients. ECG or echocardiographic signs, or both, of LV abnormalities were the most frequent abnormalities, and patients with cardiac injury experienced more RV than LV systolic dysfunction.

Incidence, clinical features and outcome of Takotsubo syndrome in the intensive care unit.

BACKGROUND: Most diseases encountered in the intensive care unit are associated with major stress that can potentially trigger Takotsubo syndrome. Many severe cardiovascular complications are associated with Takotsubo syndrome, yet little is known about Takotsubo syndrome in the intensive care unit. AIMS: We sought to determine the incidence of Takotsubo syndrome, and to describe its clinical features and outcome in an intensive care unit. METHODS: This prospective single-centre study included all patients admitted consecutively over a 12-month period who had transthoracic echocardiography, electrocardiography and a troponin I assay performed on admission, at 24 and 48hours after admission, and at discharge and in the case of clinical worsening. RESULTS: The incidence of Takotsubo syndrome was 4.6% (13/280 patients) and female sex predominated (69.2%). The median age of the subgroup with Takotsubo syndrome was 64 (56-72) years. Pulmonary disease and sepsis were the most frequent triggers (46.2% and 38.5%, respectively). Median left ventricular ejection fraction was 29.0% (20.0-37.0). Patients with Takotsubo syndrome presented with shock and arrhythmias and needed ventilation more frequently than patients without Takotsubo syndrome (69.2% vs. 36.3%, P=0.035; 46.2% vs. 13.5%, P=0.006; and 92.3% vs. 60.7%, P=0.021), but mortality rates were similar. The median delay to cardiac index recovery, when impaired, was 2.0 (1.0-2.75) days, and that of left ventricular ejection fraction was 12.5 (7-14.75) days. CONCLUSION: Takotsubo syndrome in the intensive care unit is not uncommon and is associated with substantial haemodynamic and respiratory instability. New-onset arrhythmias and respiratory and haemodynamic worsening could arouse suspicion of and prompt screening for Takotsubo syndrome in the intensive care unit.

Is Inappropriate Response to Cosyntropin Stimulation Test an Indication of Corticosteroid Resistance in Septic Shock?

We recently published a comparison of two hydrocortisone dosage regimens in patients with septic shock. We compare the results conferred by the two regimens as a function of the response to cosyntropin stimulation test (CST). Patients with septic shock were treated by one of two hydrocortisone regimens: either a 50-mg intravenous bolus every 6 h during 7 days (200 mg group; n = 49), or a 100-mg initial bolus followed by a continuous infusion of 300 mg daily for 5 days (300 mg group; n = 50). Nonresponders was defined as a CST response of 9 µg/dL or less. Nonresponders had more severe septic shock, greater fluid resuscitation needs, and greater vasopressor dependence than responders. When analyzed only as a function of CST results, there was no difference in survival between responders and nonresponders. However, analyses crossing CST results and the treatment regimens showed that patients who were responders and in the 300 mg group had significantly less intensive care unit mortality compared with responders in the 200 mg group (respective mortality of 24% vs. 55% [relative risk 0.43, 95% confidence interval, 0.20 to 0.94, P = 0.018]). Multivariate analysis identified baseline blood cortisol as an independent prognostic factor for 28-day mortality in all groups (hazard ratio 1.002, 95% confidence interval, 1.001 to 1.002, P ≤ 0.0001). The results suggest that in patients who respond to CST, hydrocortisone can provide a dose-dependent benefit. In contrast, nonresponse may indicate corticosteroid resistance. This heterogeneity of response to hydrocortisone may explain the difficulties encountered when trying to demonstrate its benefit in septic shock.

Seawater drowning-associated pneumonia: a 10-year descriptive cohort in intensive care unit.

BACKGROUND: Pneumonia is one of the major complications of drowning, but the optimal empirical antibiotic treatment is not clearly defined. Multidrug-resistant (MDR) bacteria and fungi have been identified in a recent series of freshwater drowning-associated pneumonia. However, microbial data in seawater drowning are scarce. The objective of the study is to describe the microorganisms isolated in early respiratory specimens obtained from seawater drowning-associated pneumonia and to provide their antibiotic susceptibility pattern. METHODS: All patients admitted for seawater drowning between 2003 and 2013 to two intensive care units, from the region in France with the highest drowning rate, were retrospectively included. Demographics, antimicrobial therapy and microbiological data from respiratory samples collected within the first 48 h after admittance were analyzed. RESULTS: Seventy-four drowned patients were included, of which 36 (49%) were diagnosed by the clinician as having early pneumonia. Concerning the overall population, the median simplified acute physiology score (version 2) was 45 (30-65), and the mortality was 26%. Twenty-four respiratory samples from different patients were obtained within the first 48 h. Sixteen were positive. The main microorganisms found were Enterobacteriaceae (Enterobacter spp., Klebsiella spp. and Escherichia coli) and Gram-positive aerobic cocci (Streptococcus pneumonia and Staphylococcus aureus) with a low rate of antimicrobial resistance. No MDR bacteria or fungi were identified. However, among the positive respiratory samples collected, 5/16 (31%) grew bacteria with natural resistance to amoxicillin-clavulanate, the first-line antibiotic commonly used in our cohort. Resistance was only found among Gram-negative bacteria and from respiratory samples of patients with a higher drowning grade at admission (p = 0.01). CONCLUSIONS: This 10-year descriptive study, the largest cohort to date, provides early respiratory samples from seawater drowning patients. The microorganisms retrieved were either mostly part of the human oro-pharyngeal flora or Enterobacteriaceae and displayed low rates of antimicrobial resistance. Respiratory samples should nonetheless be collected at admittance to the ICU to avoid inappropriate treatment. Empiric use of cephalosporin could be restricted to severe patients or if Gram-negative bacilli are found after direct examination.

Effects of Increasing Hydrocortisone to 300 mg Per Day in the Treatment of Septic Shock: a Pilot Study.

PURPOSE: The Surviving Sepsis Campaign guidelines recommend hydrocortisone in septic shock only when fluid resuscitation and vasopressors fail to restore hemodynamic stability. Hydrocortisone administration modalities are supported only by low-grade recommendations. Our main objective here was to determine differences in 28-day mortality between two low-dose hydrocortisone regimens for the treatment of septic shock. METHODS: We performed a multicenter, prospective, randomized, double-blind, pilot study in four adult medical intensive care units. Patients presenting septic shock were rapidly administered one of two regimens of hydrocortisone, either a 50-mg intravenous bolus every 6 h during 7 days (200-mg group; n = 59) or a 100-mg initial bolus followed by a continuous infusion of 300 mg daily for 5 days (300-mg group; n = 63). Hydrocortisone was stopped abruptly at the end of treatment. RESULTS: There were no significant differences between the 200-mg and 300-mg groups as concerns 28-day mortality (respectively 52.5% vs. 44.4% [RR 0.84, 95% CI, 0.58-1.22, P = 0.47]), refractory shock incidence or delay from shock to vasopressor cessation. There were also no differences in adverse events between the groups. Shock relapse after hydrocortisone cessation was independent of hydrocortisone regimens, but it was associated with the persistence of infection and the use of etomidate. The resumption of hydrocortisone due to shock relapse was significantly more frequent in the 300-mg group. CONCLUSION: We found no differences in mortality or adverse events between the two hydrocortisone administration regimens. Shock relapse was significantly associated with the persistence of infection and the use of etomidate.

Assessment of muscle tissue oxygen saturation after out-of-hospital cardiac arrest.

PURPOSE: Pathophysiology of cardiac arrest corresponds to an ischemia-reperfusion syndrome with deep impairment of microcirculation. Muscular tissue oxygen saturation (StO2) is a noninvasive method of evaluation of microcirculation. Our study was aimed at assessing the prognosis value of muscular StO2 in patients admitted for out-of-hospital cardiac arrest (OHCA) and treated with hypothermia. MATERIALS AND METHODS: We conducted a prospective bicentric observational study including OHCA patients treated with therapeutic hypothermia. Baseline StO2, derived variables (desaturation and resaturation slopes), and lactate levels were compared at different times between patients with good and poor outcomes. Prognosis was assessed by the Cerebral Performance Category (CPC) score at 6 months after admission (CPC 1-2, good outcome; CPC 3-5, poor outcome). RESULTS: Forty-four patients were included, 17 good and 27 poor outcomes at 6 months. At admission, StO2 and lactate levels were lower in good outcome patients. Desaturation and resaturation slopes did not differ between groups. CONCLUSIONS: After an OHCA treated with therapeutic hypothermia, StO2 was correlated with outcome. Further research is needed to better understand the pathophysiological process underlying our results.

A therapeutic challenge: catastrophic anti-phospholipid syndrome with diffuse alveolar haemorrhage.

Diffuse alveolar haemorrhage (DAH) complicating primary catastrophic anti-phospholipid syndrome (CAPS) was diagnosed in a 50-year-old female patient. Treatment strategies are limited for this often life-threatening autoimmune disease that requires aggressive immunosuppression. In the absence of clinically validated treatment strategies, high-dose steroids associated with plasma exchange and eventually intravenous immunoglobulins were used to manage the disease. Its severity prompted the initiation of rituximab that was administered weekly for four consecutive weeks. Anticoagulation therapy, on the other hand, needed to be discontinued due to the major haemorrhagic episodes. This combination treatment provided an effective control of the CAPS-associated DAH and helped achieve clinical remission.

Monitoring CO2 in shock states.

The primary end point when treating acute shock is to restore blood circulation, mainly by reaching macrocirculatory parameters. However, even if global haemodynamic goals can be achieved, microcirculatory perfusion may remain impaired, leading to cellular hypoxia and organ damage. Interestingly, few methods are currently available to measure the adequacy of organ blood flow and tissue oxygenation. The rise in tissue partial pressure of carbon dioxide (CO2) has been observed when tissue perfusion is decreased. In this regard, tissue partial pressure of CO2 has been proposed as an early and reliable marker of tissue hypoxia even if the mechanisms of tissue partial pressure in CO2 rise during hypoperfusion remain unclear. Several technologies allow the estimation of CO2 content from different body sites: vascular, tissular (in hollow organs, mucosal or cutaneous), and airway. These tools remain poorly evaluated, and some are used but are not widely used in clinical practice. The present review clarifies the physiology of increasing tissue CO2 during hypoperfusion and underlines the specificities of the different technologies that allow bedside estimation of tissue CO2 content.

Tako-Tsubo cardiomyopathy presenting with cardiogenic shock successfully treated with milrinone: a case report.

We report the case of a middle age patient presenting with Tako-Tsubo cardiomyopathy (TTC) complicated by cardiogenic shock that was successfully handled with milrinone. A 64-year old man presented with cardiogenic shock after benzodiazepine and alcohol intoxication. A slight elevation of troponin and typical left ventricular ballooning without coronary lesions suggested TTC. Within a few hours milrinone infusion normalized the cardiac index. TTC is responsible for severe transient left ventricular dysfunction occurring after physical or psychological stress. The major pathophysiological mechanism involved is disproportionate catecholamine secretion, which may stun the myocardium. We considered if treatment of this unique physiopathology with catecholamines could be dangerous in these patients and if alternative inotropes such as milrinone should be preferred.

Acquiring procedural skills in ICUs: a prospective multicenter study*.

OBJECTIVES: Providing appropriate training of procedural skills to residents while ensuring patient safety through trainee supervision is a difficult and constant challenge. We sought to determine how effective and safe procedural skill acquisition is in French ICUs and to identify failure and complication risk factors. DESIGN: Multicenter prospective observational study. Invasive procedures performed by residents were recorded during two consecutive semesters. SETTING: Eighty-four residents. SUBJECTS: Eighty-four residents. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Number of invasive procedures performed, failure and complication rates, supervision, and assistance provided. Five thousand six hundred seventeen procedures were prospectively studied: 1,007 tracheal intubations, 1,272 arterial and 2,586 central venous catheter insertions, 457 fiberoptic bronchoscopies, and 295 chest tube insertions. During the semesters, residents performed a median of 10 intubations, 14 arterial catheter insertions, and 26 central venous catheter insertions. Complication rates were low, similar to those in the literature: 8.6% desaturation and 7.4% esophageal placement during intubation; 0.4% and 2.3% pneumothorax with jugular and subclavian central venous catheter insertions, respectively. We identified risk factors for failure and complications. Higher rates of failure and complications for intubation were associated with residents with no or little previous experience (p < 0.001); failure of internal jugular vein catheterization was associated with left-side insertion (p = 0.005) and absence of mechanical ventilation (p = 0.007). Supervision and assistance were more frequent at the beginning of the semester and for intubation and chest tube insertion. Finally, residents had less access to fiberoptic bronchoscopy and chest tube insertion. CONCLUSION: Procedural skills acquisition by residents in the ICU appears feasible and safe with complication rates comparable to what has previously been reported. We identified specific procedures and situations associated with higher failure and complication rates that could require proactive training. Questions still remain regarding minimal numbers of procedures to attain competence and how best to provide procedural training.

Diagnostic accuracy of early urinary index changes in differentiating transient from persistent acute kidney injury in critically ill patients: multicenter cohort study.

INTRODUCTION: Urinary indices have limited effectiveness in separating transient acute kidney injury (AKI) from persistent AKI in ICU patients. Their time-course may vary with the mechanism of AKI. The primary objective of this study was to evaluate the diagnostic value of changes over time of the usual urinary indices in separating transient AKI from persistent AKI. METHODS: An observational prospective multicenter study was performed in six ICUs involving 244 consecutive patients, including 97 without AKI, 54 with transient AKI, and 93 with persistent AKI. Urinary sodium, urea and creatinine were measured at ICU admission (H0) and on 6-hour urine samples during the first 24 ICU hours (H6, H12, H18, and H24). Transient AKI was defined as AKI with a cause for renal hypoperfusion and reversal within 3 days. RESULTS: Significant increases from H0 to H24 were noted in fractional excretion of urea (median, 31% (22 to 41%) and 39% (29 to 48%) at H24, P<0.0001), urinary urea/plasma urea ratio (15 (7 to 28) and 20 (9 to 40), P<0.0001), and urinary creatinine/plasma creatinine ratio (50 (24 to 101) and 57 (29 to 104), P=0.01). Fractional excretion of sodium did not change significantly during the first 24 hours in the ICU (P=0.13). Neither urinary index values at ICU admission nor changes in urinary indices between H0 and H24 performed sufficiently well to recommend their use in clinical setting (area under the receiver-operating characteristic curve≤0.65). CONCLUSION: Although urinary indices at H24 performed slightly better than those at H0 in differentiating transient AKI from persistent AKI, they remain insufficiently reliable to be clinically relevant.

The early phase of human sepsis is characterized by a combination of apoptosis and proliferation of T cells.

PURPOSE: T cell activation as well as unresponsiveness has been described in separate studies in sepsis. Our aim was to establish the coexistence of both T cell fate in human sepsis. PATIENTS AND METHODS: This is a cross-sectional study of 48 patients presenting with severe sepsis or septic shock and 15 healthy controls. Cytofluorometric techniques were used to quantify T cell activation, apoptosis, proliferation, expression of costimulatory molecules, and cytokine secretion. RESULTS: Patients with sepsis were characterized by a significant increase in the percentage of activated T cell subsets, as measured using CD69 marker, compared with healthy controls (P<.05). T cell proliferation as measured through Ki67 expression was obvious in infected patients for both CD4 and CD8 T cell subsets compared with controls (P ≤.006). T cell subset apoptosis as measured using Hoechst dye was also increased in infected patients compared with controls (P ≤.002). CD4 T cell proliferation was correlated with interleukin 2 secretion (R(2)=0.84, P<.001), whereas up-regulation of CD4 T cell apoptosis was correlated with CTLA-4 expression (R(2)=0.24, P=.001). No such similar relationship was observed for CD8(+) T cells. CONCLUSIONS: Concomitant T cell proliferation and T cell apoptosis are observed in human sepsis, being related to a different pathway.

CT-guided percutaneous catheter drainage of acute infectious necrotizing pancreatitis: assessment of effectiveness and safety.

OBJECTIVE: The purpose of this study is to assess retrospectively the effectiveness and safety of CT-guided percutaneous drainage and to determine the factors influencing clinical success and mortality in patients with infectious necrotizing pancreatitis. MATERIALS AND METHODS: From April 1997 to December 2005, 48 consecutive patients (33 men and 15 women; median age, 58.5 years) with proven infectious necrotizing pancreatitis underwent percutaneous catheter drainage via CT guidance. Evaluated factors included clinical, biologic, and radiologic scores; drainage and catheter characteristics; and complications. Clinical success was defined as control of sepsis without requirement for surgery. Univariate analysis was performed to determine factors that could have affected the clinical success and the mortality rates. RESULTS: Clinical success was achieved in 31 of 48 patients (64.6%) and was significantly associated with Ranson score (p = 0.01) and with the delay between admission and the beginning of the drainage (p = 0.005), with a calculated threshold delay of 18 days (p = 0.001). The global mortality rate (14/48 [29%]) was also influenced by the Ranson score (p = 01) and the delay of drainage (p = 0.04) with the same threshold delay (p = 0.01). Only two major nonlethal procedure-related complications were observed. CONCLUSION: Percutaneous catheter drainage is a safe and effective technique to treat acute infectious necrotizing pancreatitis.

Transthoracic Echocardiography with Doppler Tissue Imaging predicts weaning failure from mechanical ventilation: evolution of the left ventricle relaxation rate during a spontaneous breathing trial is the key factor in weaning outcome.

INTRODUCTION: There is growing evidence to suggest that transthoracic echocardiography (TTE) should be used to identify the cardiac origin of respiratory weaning failure. THE AIMS OF OUR STUDY WERE: first, to evaluate the ability of transthoracic echocardiography, with mitral Doppler inflow E velocity to annular tissue Doppler Ea wave velocity (E/Ea) ratio measurement, to predict weaning failure from mechanical ventilation in patients, including those with atrial fibrillation; and second, to determine whether the depressed left ejection fraction and/or diastolic dysfunction participate in weaning outcome. METHODS: The sample included patients on mechanical ventilation for over 48 hours. A complete echocardiography was performed just before the spontaneous breathing trial (SBT) and 10 minutes after starting the SBT. Systolic dysfunction was defined by a left ventricle ejection fraction under 50% and relaxation impairment by a protodiastolic annulus mitral velocity Ea under or equal to 8 cm/second. RESULTS: A total of 68 patients were included. Twenty failed the weaning process and the other 48 patients succeeded. Before the SBT, the E/Ea ratio was higher in the failed group than in the successful group. The E/Ea measured during the SBT was also higher in the failed group. The cut-off value, obtained from receiver operating characteristics (ROC) curve analysis, to predict weaning failure gave an E/Ea ratio during the SBT of 14.5 with a sensitivity of 75% and a specificity of 95.8%. The left ventricular ejection fraction did not differ between the two groups whereas Ea was lower in the failed group. Ea increased during SBT in the successful group while no change occurred in the failed group. CONCLUSIONS: Measurement of the E/Ea ratio with TTE could predict weaning failure. Diastolic dysfunction with relaxation impairment is strongly associated with weaning failure. Moreover, the impossibility of enhancing the left ventricle relaxation rate during the SBT seems to be the key factor of weaning failure. In contrast, the systolic dysfunction was not associated with weaning outcome.

Fatal fulminant primary hepatitis B virus infections with G1896A precore viral mutants in southeastern France.

Fulminant hepatitis has been shown to occur in about 1% of acute hepatitis B virus (HBV) infections, and its mortality rate is nearly 70%. Specific HBV genotypic features have been pointed out in fulminant acute hepatitis B worldwide, but these associations remain controversial. We describe all four primary HBV infections diagnosed in 2008 in our institution in Marseille, southeastern France, including two fatal cases. HBV genotypes were D or E. Precore G1896A HBV mutants were detected in both fatal fulminant primary HBV infections. Hepatitis B surface antigen and hepatitis B e antigen (HBeAg) were negative in two and three cases, respectively, despite HBV DNA detection. Primary HBV infection remains a cause of death in France. The impact of the precore G1896A mutation on the severity of AHB deserves to be assessed in larger studies in this country.

Accuracy and precision of end-expiratory lung-volume measurements by automated nitrogen washout/washin technique in patients with acute respiratory distress syndrome.

INTRODUCTION: End-expiratory lung volume (EELV) is decreased in acute respiratory distress syndrome (ARDS), and bedside EELV measurement may help to set positive end-expiratory pressure (PEEP). Nitrogen washout/washin for EELV measurement is available at the bedside, but assessments of accuracy and precision in real-life conditions are scant. Our purpose was to (a) assess EELV measurement precision in ARDS patients at two PEEP levels (three pairs of measurements), and (b) compare the changes (Δ) induced by PEEP for total EELV with the PEEP-induced changes in lung volume above functional residual capacity measured with passive spirometry (ΔPEEP-volume). The minimal predicted increase in lung volume was calculated from compliance at low PEEP and ΔPEEP to ensure the validity of lung-volume changes. METHODS: Thirty-four patients with ARDS were prospectively included in five university-hospital intensive care units. ΔEELV and ΔPEEP volumes were compared between 6 and 15 cm H2O of PEEP. RESULTS: After exclusion of three patients, variability of the nitrogen technique was less than 4%, and the largest difference between measurements was 81 ± 64 ml. ΔEELV and ΔPEEP-volume were only weakly correlated (r2 = 0.47); 95% confidence interval limits, -414 to 608 ml). In four patients with the highest PEEP (≥ 16 cm H2O), ΔEELV was lower than the minimal predicted increase in lung volume, suggesting flawed measurements, possibly due to leaks. Excluding those from the analysis markedly strengthened the correlation between ΔEELV and ΔPEEP volume (r2 = 0.80). CONCLUSIONS: In most patients, the EELV technique has good reproducibility and accuracy, even at high PEEP. At high pressures, its accuracy may be limited in case of leaks. The minimal predicted increase in lung volume may help to check for accuracy.

Diagnostic performance of fractional excretion of urea in the evaluation of critically ill patients with acute kidney injury: a multicenter cohort study.

INTRODUCTION: Several factors, including diuretic use and sepsis, interfere with the fractional excretion of sodium, which is used to distinguish transient from persistent acute kidney injury (AKI). These factors do not affect the fractional excretion of urea (FeUrea). However, there are conflicting data on the diagnostic accuracy of FeUrea. METHODS: We conducted an observational, prospective, multicenter study at three ICUs in university hospitals. Unselected patients, except those with obstructive AKI, were admitted to the participating ICUs during a six-month period. Transient AKI was defined as AKI caused by renal hypoperfusion and reversal within three days. The results are reported as medians (interquartile ranges). RESULTS: A total of 203 patients were included. According to our definitions, 67 had no AKI, 54 had transient AKI and 82 had persistent AKI. FeUrea was 39% (28 to 40) in the no-AKI group, 41% (29 to 54) in the transient AKI group and 32% (22 to 51) in the persistent AKI group (P = 0.12). FeUrea was of little help in distinguishing transient AKI from persistent AKI, with the area under the receiver operating characteristic curve being 0.59 (95% confidence interval, 0.49 to 0.70; P = 0.06). Sensitivity was 63% and specificity was 54% with a cutoff of 35%. In the subgroup of patients receiving diuretics, the results were similar. CONCLUSIONS: FeUrea may be of little help in distinguishing transient AKI from persistent AKI in critically ill patients, including those receiving diuretic therapy. Additional studies are needed to evaluate alternative markers or strategies to differentiate transient from persistent AKI.