Comparing COVID-19 and influenza: Epidemiology, clinical characteristics, outcomes and mortality in the ICU

RATIONALE

Several authors have compared COVID-19 infection with influenza in the ICU.

OBJECTIVE

This study aimed to compare the baseline clinical profiles, care procedures, and mortality outcomes of patients admitted to the intensive care unit, categorized by infection status (Influenza vs. COVID-19).

METHODS

Retrospective observational study. Data were extracted from the Toulouse University Hospital from March 2014 to March 2021. To compare survival curves, we plotted the survival at Day-90 using the Kaplan-Meier curve and conducted a log-rank test. Additionally, we performed propensity score matching to adjust for confounding factors between the COVID-19 and influenza groups. Furthermore, we use the CART model for multivariate analysis.

RESULTS

The study included 363 patients admitted to the ICU due to severe viral pneumonia: 152 patients (41.9 %) with influenza and 211 patients (58.1 %) with COVID-19. COVID-19 patients exhibited a higher prevalence of cardiovascular risk factors, whereas influenza patients had significantly higher severity scores (SOFA: 10 [6-12] vs. 6 [3-9], p<0.01 and SAPS II: 51 [35-67] vs. 37 [29-50], p<0.001). Overall mortality rates were comparable between the two groups (27.6 % (n = 42) in the influenza group vs. 21.8 % (n = 46) in the COVID-19 group, p=NS). Mechanical ventilation was more commonly employed in the influenza group (76.3 % (n = 116) vs. 59.7 % (n = 126), p<0.001); however, COVID-19 patients required longer durations of mechanical ventilation (18 [9-29] days vs. 13 [5-24] days, p<0.006) and longer hospital stays (23 [13-34] days vs. 18.5 [9-34.5] days, p = 0.009). The CART analysis revealed that the use of extra renal replacement therapy was the most influential prognostic factor in the influenza group, while the PaO2/FiO2-PEEP ratio played a significant role in the COVID-19 group.

CONCLUSIONS

Despite differences in clinical presentation and prognostic factors, the mortality rates at 90 days, after adjusting for confounding factors, were similar between COVID-19 and influenza patients.

Influence of arterial blood gases on the renal arterial resistive index in intensive care unit

BACKGROUND

Renal artery Doppler sonography with resistive index (RI) determination is a noninvasive, fast, and reliable diagnostic tool increasingly used in the intensive care unit (ICU) to predict and assess the reversibility of acute kidney injury (AKI). However, interpreting the RI can be challenging due to numerous influencing factors. While some studies have explored various confounding factors, arterial blood gases have received limited attention. Therefore, our study aims to evaluate the impact of arterial blood gases on the RI in the ICU setting.

METHODS

This prospective observational study enrolled ICU patients who required blood gas analysis and had not experienced significant hemodynamic changes recently. The RI was measured using standardized Doppler ultrasound within an hour of the arterial blood gases sampling and analysis.

RESULTS

A total of sixty-four patients were included in the analysis. Univariate analysis revealed a correlation between the RI and several variables, including PaCO2 (R = 0.270, p = 0.03), age (R = 0.574, p < 0.0001), diastolic arterial pressure (DAP) (R = - 0.368, p = 0.0028), and SaO2 (R = - 0.284, p = 0.0231). Multivariate analysis confirmed that age > 58 years and PaCO2 were significant factors influencing the RI, with respective odds ratios of 18.67 (p = 0.0003) and 1.132 (p = 0.0267).

CONCLUSION

The interpretation of renal arterial RI should take into account thresholds for PaCO2, age, and diastolic arterial pressure. Further studies are needed to develop a comprehensive scoring system that incorporates all these cofactors for a reliable analysis of RI levels. Trial registration This observational study, registered under number 70-0914, received approval from local Ethical Committee of Toulouse University Hospital.

Use of Percutaneous Atrioseptotosmy for Left Heart Decompression During Veno-Arterial Extracorporeal Membrane Oxygenation Support: An Observational Study

Background

Left ventricular overload is frequent under veno‐arterial extracorporeal membrane oxygenation, which is associated with a worsening of the prognosis of these patients. Several left heart decompression (LHD) techniques exist. However, there is no consensus on their timing and type. We aimed to describe characteristics and outcomes of patients undergoing LHD and to compare percutaneous atrioseptostomy (PA) to other LHD techniques.

Methods and Results

Retrospective analysis was conducted of consecutive and prospectively collected patients supported by veno‐arterial extracorporeal membrane oxygenation for refractory cardiac arrest or cardiogenic shock between January 2015 and April 2018, with a 90‐day follow‐up in our tertiary center. Patients were divided according to the presence of LHD, and then according to its type (PA versus others). Thirty‐nine percent (n=63) of our patients (n=163) required an LHD. Patients with LHD had lower left ventricular ejection fraction, more ischemic cardiomyopathy, and no drug intoxication‐associated cardiogenic shock. PA was frequently used for LHD (41% of first‐line and 57% of second‐line LHD). PA appears safe and fast to realize (6.3 [interquartile range, 5.8–10] minutes) under fluoroscopic and echocardiographic guidance, with no acute complications. PA was associated with fewer neurological complications (12% versus 38%, P=0.02), no need to insert a second LHD (0% versus 19%, P=0.04), and higher 90‐day survival compared with other techniques (42% versus 19%, log‐rank test P=0.02), despite more sepsis (96% versus 73%, P=0.02) and blood transfusions (13.5% versus 7%, P=0.01). Multivariate analysis confirms the association between PA and 90‐day survival (hazard ratio, 2.53 [1.18–5.45], P=0.019).

Conclusions

LHD was frequently used for patients supported with veno‐arterial extracorporeal membrane oxygenation, especially in cases of ischemic cardiomyopathy and low left ventricular ejection fraction. PA seems to be a safe and efficient LHD technique associated with greater mid‐term survival justifying the pursuit of research on this topic.

Predictors of weaning failure in case of VA ECMO implantation

The use of veno-arterial extracorporeal membrane oxygenation (VA ECMO) for the treatment of refractory cardiogenic shock has increased significantly. Nevertheless, early weaning may be advisable to reduce the potential for severe complications. Only a few studies focusing on ECMO weaning predictors are currently available. Our objective was to evaluate factors that may help predict failure during VA ECMO weaning. We included 57 patients on VA ECMO support previously considered suitable for weaning based on specific criteria. Clinical, haemato-chemical and echocardiographic assessment was considered before and after a "weaning test" (ECMO flow < 2 L/min for at least 60 min). ECMO removal was left to the discretion of the medical team blinded to the results. Weaning failure was defined as a patient who died or required a new VA ECMO, heart transplant or LVAD 30 days after ECMO removal. Thirty-six patients (63.2%) were successfully weaned off VA ECMO, of whom 31 (54.4%) after the first weaning test. In case of first test failure, 3 out of 7 patients could be weaned after a 2nd test and 3 out of 4 patients after a 3rd test. Pre-existing ischemic heart disease (OR 9.6 [1.1-83]), pre-test left ventricular ejection fraction (LVEF) ≤ 25% and/or post-test LVEF ≤ 40% (OR 11 [0.98-115]), post-test systolic blood pressure ≤ 120 mmHg (OR 33 [3-385]), or length of ECMO support > 7 days (OR 24 [2-269]) were predictors of weaning failure. The VA ECMO weaning test failed in less than 40% of patients considered suitable for weaning. Clinical and echocardiographic criteria, which are easily accessible by a non-expert intensivist, may help increase the probability of successful weaning.

Evolution of Platelet Activation Parameters During Septic Shock in Intensive Care Unit

During severe sepsis, platelet activation may induce disseminate microvascular thrombosis, which play a key role in critical organ failure. Crucially, most of the studies in this field have explored platelet-leukocyte interactions in animal models, or explored platelets under the spectrum of thrombocytopenia or disseminated intravascular coagulation and have not taken into account the complex interplay that might exist between platelets and leukocytes during human septic shock nor the kinetics of platelet activation. Here, we assessed platelet activation parameters at the admission of patients with sepsis to the intensive care unit (ICU) and 48 hours later. Twenty-two patients were enrolled in the study, thirteen (59.1%) of whom were thrombocytopenic. The control group was composed of twelve infection-free patients admitted during the study period. The activation parameters studied included platelet-leukocyte interactions, assessed by flow cytometry in whole blood, as well as membrane surface and soluble platelet activation markers measured by flow cytometry and dedicated ELISA kits. We also investigated platelet aggregation and secretion responses of patients with sepsis following stimulation, compared to controls. At admission, the level of circulating monocyte-platelet and neutrophil-platelet heterotypic aggregates was significantly higher in sepsis patients compared to controls and returned to a level comparable to controls or even below 48 hours later. Basal levels of CD62P and CD63 platelet membrane exposure at admission and 48 hours later were low and similar to controls. In contrast, plasma level of soluble GPVI and soluble CD40 ligand was significantly increased in septic patients, at the two times of analysis, reflecting previous platelet activation. Platelet aggregation and secretion responses induced by specific agonists were significantly decreased in septic conditions, particularly 48 hours after admission. Hence, we have observed for the first time that critically ill septic patients compared to controls have both an early and durable platelet activation while their circulating platelets are less responsive to different agonists.

Prevalence of malnutrition in coronavirus disease 19: the NUTRICOV study

Recent European Society of Parenteral and Enteral Nutrition guidelines highlighted the interest of prevention, diagnosis and treatment of malnutrition in the management of coronavirus disease 19 (COVID-19) patients. The aim of our study was to evaluate the prevalence of malnutrition in patients hospitalised for COVID-19. In a prospective observational cohort study malnutrition was diagnosed according to the Global Leadership Initiative on Malnutrition (GLIM) two-step approach. Patients were divided into two groups according to the diagnosis of malnutrition. Covariate selection for the multivariate analysis was based on P <0·2 in univariate analysis, with a logistic regression model and a backward elimination procedure. A partitioning of the population was realised. Eighty patients were prospectively enrolled. Thirty patients (37·5 %) had criteria for malnutrition. The need for intensive care unit admission (n 46, 57·5 %) was similar in the two groups. Three patients who died (3·75 %) were malnourished. Multivariate analysis exhibited that low BMI (OR 0·83, 95 % CI 0·73, 0·96, P = 0·0083), dyslipidaemia (OR 29·45, 95 % CI 3·12, 277·73, P = 0·0031), oral intake reduction <50 % (OR 3·169, 95 % CI 1·04, 9·64, P = 0·0422) and glomerular filtration rate (Chronic Kidney Disease Epidemiology Collaboration; CKD-EPI) at admission (OR 0·979, 95 % CI 0·96, 0·998, P = 0·0297) were associated with the occurrence of malnutrition. We demonstrate the existence of a high prevalence of malnutrition in a general cohort of COVID-19 inpatients according to GLIM criteria. Nutritional support in COVID-19 care seems an essential element.

Cardiac Imaging Phenotype in Patients with Coronavirus Disease 2019 - COCARDE study: prospective observational study

Background

The effects of SARS-CoV-2 (COVID-19) on the myocardium and their role in the clinical course of infected patients are still unknown. The severity of SARS-CoV-2 is driven by hyperinflammation, and the effects of SARS-CoV-2 on the myocardium may be significant. This study proposes to use bedside observations and biomarkers to characterize the association of COVID-19 with myocardial injury.

Objective

The aim of the study is to describe the myocardial function and its evolution over time in patients infected with SARS-CoV-2 and to investigate the link between inflammation and cardiac injury.

Methods

This prospective, monocentric, observational study enrolled 150 patients with suspected or confirmed SARS-CoV-2 infection at Toulouse University Hospital, Toulouse, France. Patients admitted to the intensive care unit (ICU), regular cardiologic ward, and geriatric ward of our tertiary university hospital were included during the pandemic period. Blood sampling, electrocardiography, echocardiography, and morphometric and demographic data were prospectively collected.

Results

A total of 100 patients were included. The final enrolment day was March 31, 2020, with first report of results at the end of the first quarter of 2021. The first echocardiographic results at admission of 31 patients of the COCARDE-ICU substudy population show that biological myocardial injury in COVID-19 has low functional impact on left ventricular systolic function.

Conclusions

A better understanding of the effects of COVID-19 on myocardial function and its link with inflammation would improve patient follow-up and care.

Trial Registration

Clinicaltrials.gov NCT04358952; https://clinicaltrials.gov/ct2/show/NCT04358952

International Registered Report Identifier (IRRID)

DERR1-10.2196/24931

Diaphragmatic speckle tracking imaging for 2D-strain assessment in mechanical ventilation weaning test

Ultrasound (US) is recognized as a useful tool for detecting lung physiology and pathology. Lung US is compared with standard techniques for evaluating lung structure and function such as computed tomography and pulmonary function tests. At present, markers of normal physiology and pathology are detected using expected image patterns. Detecting the latter depends on the experience of the operator. Diaphragmatic dysfunction is a particularly frequent problem in intensive care. Diaphragmatic dysfunction is easily assessed using lung US. Speckle tracking analysis, a known method for assessing tissue displacement and deformation in cardiology, is proposed to be utilized in lung US for detecting and quantifying lung sliding. Using speckle tracking analysis to diaphragmatic deformation quantification could be an informative and new tool for weaning from mechanical ventilation.

Assessment of lung ultrasound for early detection of respiratory complications in thoracic surgery

BACKGROUND AND OBJECTIVES

To assess lung ultrasound for the diagnosis and monitoring of respiratory complications in thoracic surgery.

METHODS

Prospective observational study in a University hospital, single institution. Adult patients scheduled for pulmonary resection surgery excluding pneumonectomy. An ultrasound follow-up was performed from the day before the surgery to the third day after surgery with calculation of B-line and lung score (reaeration and loss of aeration scores). Respiratory complications were collected throughout the hospitalization period.

RESULTS

Fifty-six patients were included. Eighteen patients presented a respiratory complication (32%), and they presented significantly higher BMI and ASA scores. Patients operated by videothoracoscopy were less at risk of complications. At day 3, a reaeration score ≤ 2 on the ventilated side or ≤ -2 on the operated side, and a B-line score>6 on the operated side were in favor of a complication.

CONCLUSION

Lung ultrasound can help in the diagnosis of respiratory complications following pulmonary resection surgery.

Anaesthesiologists' clinical judgment accuracy regarding preoperative full stomach: Diagnostic study in urgent surgical adult patients

BACKGROUND

In urgent situations, preoperative full stomach assessment mostly relies on clinical judgment. Our primary objective was to assess the diagnostic performance of clinical judgment for the preoperative assessment of full stomach in urgent patients compared to gastric point-of-care ultrasound (PoCUS). Our secondary objective was to identify risk factors associated with PoCUS full stomach in urgent patients.

METHODS

We led a prospective observational study at our Hospital, between January and July 2016. Adult patients admitted for urgent surgery were eligible. Patients with altered gastric sonoanatomy, interventions reducing stomach content, impossible lateral decubitus were excluded. Clinical judgment and risk factors of full stomach were collected before gastric PoCUS measurements. Ultrasonographic full stomach was defined by solid contents or liquid volume ≥ 1.5 ml kg^-1. Diagnostic performance was assessed through sensitivity, specificity, accuracy, positive and negative predictive value.

RESULTS

The prevalence of clinical and PoCUS full stomach in 196 included patients was 29% and 27%, respectively. Positive and negative predictive values were 42% (95% CI: 32.3-52.6%) and 79% (95% CI: 74.9-83.4%), respectively. Patients with PoCUS full stomach were clinically misdiagnosed in 55% of cases. PoCUS full stomach was associated with abdominal or gynaecological-obstetrical surgery (OR 3.6, 95% CI: 1.5-8.8, P < 0.01) but not with fasting durations. Positive solid intake after illness onset with respect to 6-h solid fasting rule was associated with PoCUS low-risk gastric content (OR 0.4, 95% CI: 0.2-0.9, P = 0.03).

CONCLUSIONS

Clinical judgment showed poor-to-moderate performance in urgent surgical patients for the diagnosis of full stomach. Gastric PoCUS should be used to assess risk of full stomach in this population.

A study of patients' quality of life more than 5 years after trauma: a prospective follow-up

BACKGROUND

The long-term fate of severely injured patients in terms of their quality of life is not well known. Our aim was to assess the quality of life of patients who have suffered moderate to severe trauma and to identify primary factors of long-term quality of life impairment.

METHODS

A prospective monocentric study conducted on a number of patients who were victims of moderate to severe injuries during the year 2012. Patients were selected based on an Injury Severity Score (ISS) more than or equal to 9. Quality of life was assessed by the MOS SF-36 and NHP scores as a primary evaluation criterion. The secondary evaluation criteria were the determination of the socio-economic impact on quality of life and the identification of factors associated with disability.

RESULTS

Two hundred and eight patients were contacted by e-mail or telephone. Fifty-five patients participated in this study (with a participation level of 26.4%), including 78.2% men, with a median age of 46. Significant alterations in quality of life were observed with the NHP and MOS SF-36 scale, including physical and psychological components. This resulted in a major socio-economic impact as 26% of the patients could not resume their professional activities (n = 10), 20% required retraining in other lines of work, and 36.4% had a disability status. The study showed that scores ≤ 85 on the physical functioning variable of the MOS SF 36 scale was associated with disability.

CONCLUSION

More than five years after a moderate to severe injury, patients' quality of life was significantly impacted, resulting in significant socio-economic consequences. Disability secondary to major trauma seems to be associated with a score ≤ 85 on the physical functioning dimension of the MOS SF-36 scale. This study raises the question of whether or not early rehabilitation programs should be implemented in order to limit the long-term impact of major trauma.

Hydroxychloroquine in Coronavirus Disease 2019 Patients: What Still Needs to Be Known About the Kinetics

Different dosage regimens of hydroxychloroquine are used to manage COVID-19 patients, without information on the pharmacokinetics in this population.Blood samples (n=101) were collected from 57 COVID-19 patients for 7 days and concentrations were compared with simulated kinetic profiles.Hydroxychloroquine exposure is low and cannot be predicted by other populations.

Outcome of community- versus hospital-acquired intra-abdominal infections in intensive care unit: a retrospective study

Background

To compare patients hospitalised in the intensive care unit (ICU) after surgery for community-acquired intra-abdominal infection (CA-IAI) and hospital-acquired intra-abdominal infection (HA-IAI) in terms of mortality, severity and complications.

Methods

Retrospective study including all patients admitted to 2 ICUs within 48 h of undergoing surgery for peritonitis.

Results

Two hundred twenty-six patients were enrolled during the study period. Patients with CA-IAI had an increased 28-day mortality rate compared to those with HA-IAI (30% vs 15%, respectively (p = 0.009)). At 90 days, the mortality rates were 36.7 and 37.5% in the CA-IAI group and HA-IAI group, respectively, with a similar APACHE II score on admission (median: 21 [15–25] vs. 21 [15–24] respectively, p = 0.63). The patients with HA-IAI had prolonged ICU and hospital stays (median: 17 [7–36] vs. 6[3–12] days, p < 0.001 and 41 [24–66] vs. 17 [7–32] days, p = 0.001), and experienced more complications (reoperation and reintubation) than those with CA-IAI.

Conclusion

CA-IAI group had higher 28-day mortality rate than HA-IAI group. Mortality was similar at 90 days but those with HA-IAI had a prolonged ICU and hospital stay. In addition, they developed more complications.

Kinin B1 receptor: a potential therapeutic target in sepsis-induced vascular hyperpermeability

Background

In sepsis, the endothelial barrier becomes incompetent, with the leaking of plasma into interstitial tissues. VE-cadherin, an adherens junction protein, is the gatekeeper of endothelial cohesion. Kinins, released during sepsis, induce vascular leakage and vasodilation. They act via two G-protein coupled receptors: B1 (B1R) and B2 (B2R). B1R is inducible in the presence of pro-inflammatory cytokines, endotoxins or after tissue injury. It acts at a later stage of sepsis and elicits a sustained inflammatory response. The aim of our study was to investigate the relationships between B1R and VE-cadherin destabilization in vivo in a later phase of sepsis.

Methods

Experimental, prospective study in a university research laboratory. We used a polymicrobial model of septic shock by cecal ligation and puncture in C57BL6 male mice or C57BL6 male mice that received a specific B1R antagonist (R-954). We studied the influence of B1R on sepsis-induced vascular permeability 30 h after surgery for several organs, and VE-cadherin expression in the lung and kidneys by injecting R-954 just before surgery. The 96-h survival was determined in mice without treatment or in animals receiving R-954 as a “prophylactic” regimen (a subcutaneous injection of 200 µg/kg, prior to CLP and 24 h after CLP), or as a “curative” regimen (injection of 100 µg/kg at H6, H24 and H48 post-surgery).

Results

B1R inactivation helps to maintain MAP above 65 mmHg but induces different permeability profiles depending on whether or not organ perfusion is autoregulated. In our model, VE-cadherin was destabilized in vivo during septic shock. At a late stage of sepsis, the B1R blockade reduced the VE-cadherin disruption by limiting eNOS activation. The survival rate for mice that received R-954 after sepsis induction was higher than in animals that received an antagonist as a prophylactic treatment.

Conclusions

B1R antagonizing reduced mortality in our model of murine septic shock by limiting the vascular permeability induced by VE-cadherin destabilization through maintenance of the macrohemodynamics, consequently limiting organ dysfunctions.

Outcome of Critically Ill Patients With Influenza Infection: A Retrospective Study

Background

Influenza causes significant morbidity and mortality in adults, and numerous patients require intensive care unit (ICU) admission. Acute respiratory distress syndrome (ARDS) is clearly described in this context, but other clinical presentations exist that need to be assessed for incidence and outcome. The primary goal of this study was to describe the characteristics of patients admitted in ICU for influenza, their clinical presentation, and the 3-month mortality rate. The second objective was to search for 3-month mortality risk factors.

Methods

This is a retrospective study including all patients admitted to 3 ICUs due to influenza-related disease between October 2013 and June 2016, which assesses the 3-month mortality rate. We compared clinical presentation, biological data, and outcome at 3 months between survivors and non-survivors. We created a predicting 3-month mortality model with Classification and Regression Tree analysis.

Results

Sixty-nine patients were included, 50 patients (72.5%) for ARDS, 5 (7.2%) for myocarditis, and 14 (20.3%) for acute respiratory failure without ARDS criteria. Non-typed influenza A was found in 30 cases (43.5%), influenza A H1N1 in 18 (26.1%), H3N2 in 3 (4.3%), and influenza B in 18 cases (27.5%). The 3-month mortality rate was 29% (n = 20). Extracorporeal membrane oxygenation (ECMO) was implanted in 23 patients, without any significant increase in mortality (39% vs 24% without ECMO, P = .19). A creatinine serum superior to 96 μmol/L, an aspartate aminotransferase level superior to 68 UI/L, and a Pao₂/Fio₂ ration below 110 were associated with 3-month mortality in our predictive mortality model.

Conclusion

Influenza in ICUs may have several clinical presentations. The mortality rate is high, but ECMO may be an effective rescue therapy.

Risk factor analysis for linezolid-associated thrombocytopenia in critically ill patients

Linezolid is an antibiotic used against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus. Its primary adverse effect is haematotoxicity. The objective of this study was to analyse the risk factors for onset of thrombocytopenia in critically ill patients treated with linezolid. This was a retrospective, single-centre study of 72 patients. Platelets were measured from D0 to D20 after the start of treatment. The risk factors for thrombocytopenia were identified using a multivariate logistic regression analysis following a Monte Carlo simulation. Following ROC curve analysis, a baseline platelet count lower than 108 × 10⁹/L and a C_min higher than 4 mg/L, with respective odds ratios of 117 (95% CI [97-206]) and 3 (95% CI [1.5-6.2]) in the simulated population, were identified as risk factors. Among the source population patients combining these 2 factors, a significantly higher number developed thrombocytopenia (66.7% vs. 33.3%, p = 0.0042). A baseline platelet count lower than 108 × 10⁹/L and a C_min higher than 4 mg/L are risk factors for the onset of thrombocytopenia in critically ill patients treated with linezolid.

Kinetics of mean platelet volume predicts mortality in patients with septic shock

Introduction

Thrombocytopenia is well recognized as a poor prognosis sign associated with increased mortality and prolonged Intensive Care Unit (ICU) stay, particularly in septic patients. Mean platelet volume (MPV) could represent a relevant predictive marker of mortality. Here we investigated whether MPV kinetics during the first 15 days after hospital admission has a potential prognostic value for clinical outcome in septic shock.

Methods

We performed a retrospectively analysis of a cohort of 301 septic patients admitted in ICU. Three-month mortality was the primary endpoint. The prognostic value of the covariates of interest was ascertained by multidimensional analysis. We proposed a classification and regression trees analysis to predict survival probability.

Results

MPV kinetics was significantly different between 90-day survivors and non-survivors when followed during 15 days (except on day 3). 10-day MPV >11.6fL was an independent predictive factor of 90-day mortality (Hazard Ratio (HR) 3.796, 95% Confidence Interval (CI) [1.96–7.35], p = 0.0001) in multivariate analysis. Base excess on day 4 <1.9mmol/L was also a predictive factor of mortality (HR 2.972, 95%CI [1.38–6.40], p = 0.0054.

Conclusion

MPV increase during the first 15 days after ICU admission in non-survivors was observed during septic shock and 10-day MPV >11.6fL was an independent predictive factor of 90-day mortality. This could be explained by the emergent response to acute platelet loss during septic shock, leading to megakaryocyte rupture to produce new but potentially immature platelets in the circulation. Therefore, continuous monitoring of MPV may be a useful parameter to stratify mortality risk in septic shock.

Risk factors for acquisition of carbapenem-resistance during treatment with carbapenem in the intensive care unit: a prospective study

The emergence of carbapenemases in gram-negative aerobes is worrying. The aim of this prospective study was to estimate the incidence of acquisition of carbapenem-resistance during treatment in ICU and to identify the risk factors. This was a prospective, observational, cohort study. This study was conducted at intensive care unit, academic medical center, Toulouse Rangueil University Hospital. Patients were included if they received antibiotic treatment with carbapenem for more than 48 h. Biological samples were taken in accordance with current practice in the unit. The main endpoint was the occurrence of bacterial resistance to carbapenems occurring between the onset of treatment and the patient’s exit from the ICU. Uni- and multi-variate analyses were carried out. Of the 364 patients admitted to the unit between May and November 2014, 78 were included in our study and 16 (20.51%) developed resistance. The two main risk factors were a length of stay in ICU of more than 29 days (HR = 3.61, p = 0.01) and the presence of Pseudomonas aeruginosa in the samples taken before the start of treatment (HR = 5.31, p = 0.002). No resistance due to carbapenemase production was observed in this study. The prescription of carbapenems in the ICU setting must adhere to the expert guidelines. In light of our results, special attention must be paid to patients whose stay in intensive care is prolonged, and those in whom Pseudomonas aeruginosa is isolated from bacteriological samples taken before the beginning of antibiotic therapy.

Risk factors and the resistance mechanisms involved in Pseudomonas aeruginosa mutation in critically ill patients

Background

The objective of this study was to determine the main risk factors of Pseudomonas aeruginosa mutation as well as the mechanisms of acquired resistance.

Methods

We conducted a 2-year prospective study in patients who were carriers of a Pseudomonas aeruginosa strain and who had been admitted to a medical/surgical ICU.

Results

Of the 153 patients who were included, 34 had a mutation in their strain. In a multivariate analysis, a duration of ventilation > 24 days was a risk factor for mutation (risk ratio 4.29; CI 95% 1.94-9.49) while initial resistance was a protective factor (RR 0.36; CI 95% 0.18-0.71). In a univariate analysis, exposure of P. aeruginosa to ceftazidime was associated with an over-production of AmpC cephalosporinase and exposure to meropenem was associated with impermeability. A segmentation method based on the duration of ventilation (> 24 days), initial resistance, and exposure of strains to ceftazidime made it possible to predict at 83% the occurrence of mutation.

Conclusion

The duration of ventilation and the presence of resistance as soon as P. aeruginosa is identified are predictive factors of mutation in ICU patients.

Neurally adjusted ventilatory assist (NAVA) versus pressure support ventilation: patient-ventilator interaction during invasive ventilation delivered by tracheostomy

BACKGROUND

Prolonged weaning is a major issue in intensive care patients and tracheostomy is one of the last resort options. Optimized patient-ventilator interaction is essential to weaning. The purpose of this study was to compare patient-ventilator synchrony between pressure support ventilation (PSV) and neurally adjusted ventilatory assist (NAVA) in a selected population of tracheostomised patients.

METHODS

We performed a prospective, sequential, non-randomized and single-centre study. Two recording periods of 60 min of airway pressure, flow, and electrical activity of the diaphragm during PSV and NAVA were recorded in a random assignment and eight periods of 1 min were analysed for each mode. We searched for macro-asynchronies (ineffective, double, and auto-triggering) and micro-asynchronies (inspiratory trigger delay, premature, and late cycling). The number and type of asynchrony events per minute and asynchrony index (AI) were determined. The two respiratory phases were compared using the non-parametric Wilcoxon test after testing the equality of the two variances (F-Test).

RESULTS

Among the 61 patients analysed, the total AI was lower in NAVA than in PSV mode: 2.1% vs 14% (p < 0.0001). This was mainly due to a decrease in the micro-asynchronies index: 0.35% vs 9.8% (p < 0.0001). The occurrence of macro-asynchronies was similar in both ventilator modes except for double triggering, which increased in NAVA. The tidal volume (ml/kg) was lower in NAVA than in PSV (5.8 vs 6.2, p < 0.001), and the respiratory rate was higher in NAVA than in PSV (28 vs 26, p < 0.05).

CONCLUSION

NAVA appears to be a promising ventilator mode in tracheotomised patients, especially for those requiring prolonged weaning due to the decrease in asynchronies.

Anticoagulation Monitoring Under ECMO Support: A Comparative Study Between the Activated Coagulation Time and the Anti-Xa Activity Assay

Purpose:

Extra Corporeal Membrane Oxygenation (ECMO) is used in cases of severe respiratory and/or circulatory failure over periods of several days to several weeks. Its circuitry requires a closely monitored anticoagulation therapy that is empirically supported by activated clotting time (ACT)—a method often associated with large inter- and intraindividual variability. We aimed to compare the measurement of heparin activity with ACT and the direct measurement of the heparin activity (anti-Xa) in a large ECMO population.

Methods:

All patients treated by venoarterial or venovenous ECMO in our intensive care unit between January 2014 and December 2015 were prospectively included. A concomitant measurement of the anti-Xa activity and ACT was performed on the same sample collected twice a day (morning–evening) for unfractionated heparin adaptation with an ACT target range of 180 to 220 seconds.

Results:

One hundred and nine patients (men 69.7%, median age 54 years) treated with ECMO (70.6% venoarterial) were included. Spearman analysis found no correlation between anti-Xa and ACT (ρ < 0.4) from day 1 and worsened over time. Kappa analysis showed no agreement between the respective target ranges of ACT and anti-Xa.

Conclusions:

We demonstrate that concomitant measurement of ACT and anti-Xa activity is irrelevant in ECMO patients. Since ACT is poorly correlated with heparin dosage, anti-Xa activity appears to be a more suitable assay for anticoagulation monitoring.

Plasma free carnitine in severe trauma: Influence of the association with traumatic brain injury

BACKGROUND

Metabolic response to severe trauma requires early nutritional resuscitation. Carnitine is essential for lipolysis, the energy source during this hypercatabolic phase. However l-carnitine is not present in nutritional replacement solutions. Furthermore, free carnitine depletion, defined as carnitine plasma level under 36μmol/L, was not adequately reported in adult patients with severe trauma. The aim of this study was to assess plasma free carnitine levels and factors of variation in severe trauma.

METHOD

Our observational study concerned 38 trauma patients including 18 with traumatic brain injury (TBI). On the third day after trauma, plasma free carnitine concentration was determined (by enzymatic method) while patients received artificial nutrition.

RESULTS

Low plasmatic free carnitine concentration was evidenced in 95% of the patients with a median value of 18μmol/L (11-47). Univariate analysis showed that mean arterial pressure, serum urea, CKD-EPI and patients with TBI were significantly associated with plasma free carnitine concentration less than 18μmol/L. Lower plasma free carnitine concentration was observed in the group of patients with TBI with 17.72μmol/L (11-36) versus 21.5μmol/L (11-47) for others patients (p=0.031). Logistic regression analysis showed that severe trauma with TBI and CKD-EPI above 94mL/min/1.73m2 appeared to be independent predictor of lower free carnitine plasmatic concentration (Goodness of fit=0.87 and AUC=0.89).

CONCLUSION

Our observations support hypotheses that plasma free carnitine concentration is lowered in severe injured patients especially for TBI patients and patients with estimated GFR above 94mL/min/1.73m².

3-month prognostic impact of severe acute renal failure under veno-venous ECMO support: Importance of time of onset

PURPOSE

Veno-venous ECMO is increasingly used for the management of refractory ARDS. In this context, acute kidney injury (AKI) is a major and frequent complication, often associated with poor outcome. We aimed to identify characteristics associated with severe renal failure (Kidney Disease Improving Global Outcome (KDIGO) 3) and its impact on 3-month outcome.

METHODS

Between May 2009 and April 2016, 60 adult patients requiring VV-ECMO in our University Hospital were prospectively included.

RESULTS

AKI occurrence was frequent (75%; n=45), 51% of patients (n=31) developed KDIGO 3 - predominantly prior to ECMO insertion - and renal replacement therapy was required in 43% (n=26) of cases. KDIGO 3 was associated with a lower mechanical ventilation weaning rate (24% vs 68% for patients with no AKI or other stages of AKI; p<0.001) and a higher 90-day mortality rate (72% vs 32%, p=0.002). Multivariate logistic regression suggested that KDIGO 3 occurrence prior to ECMO insertion, as well as PaCO2>57mmHg and mSOFA>12 were independent risks factors for 90-day mortality.

CONCLUSION

KDIGO 3 AKI occurrence is correlated with the severity of patients' clinical condition prior to ECMO insertion and is negatively associated with 90-day survival.

Suicide attempt with self-made Taxus baccata leaf capsules: survival following the application of extracorporeal membrane oxygenation for ventricular arrythmia and refractory cardiogenic shock

CONTEXT

Yew intoxication has been known for many years; high dose ingestion of Taxus baccata leads to cardiac toxicity mediated by calcium and sodium channel blocking properties. We present a case report of a patient who attempted suicide after T. baccata ingestion, causing refractory cardiogenic shock requiring temporary circulatory assistance by veno-arterial extra corporeal membrane oxygenation (VA ECMO).

CASE DETAILS

A 28-year-old man was admitted to the critical care unit of a university hospital for arrhythmia after ingestion of self-made T. baccata leaf capsules. He rapidly developed cardiovascular collapse requiring mechanical ventilation, high dose intravenous catecholamines and electrical cardioversion. A femoro-femoral VA ECMO was implanted due to severe biventricular dysfunction and ventricular arrhythmia, associated with continuous renal replacement therapy. Taxol A, taxol B and baccatin III were detected and measured in both blood and urine samples by high-performance liquid chromatography tandem mass spectrometry, and kinetics suggested urinary excretion. Two days after hospital admission, VA ECMO and continuous renal replacement therapy were removed with full recovery of cardiac function.

DISCUSSION

Our experience suggests that circulatory assistance by VA ECMO and continuous renal replacement therapy seem to be effective safe second-line therapeutic options in critically ill cases of severe yew intoxication with refractory cardiogenic shock due to arrhythmia.

A whole-body physiologically based pharmacokinetic (WB-PBPK) model of ciprofloxacin: a step towards predicting bacterial killing at sites of infection

The purpose of this study was to develop a whole-body physiologically based pharmacokinetic (WB-PBPK) model for ciprofloxacin for ICU patients, based on only plasma concentration data. In a next step, tissue and organ concentration time profiles in patients were predicted using the developed model. The WB-PBPK model was built using a non-linear mixed effects approach based on data from 102 adult intensive care unit patients. Tissue to plasma distribution coefficients (Kp) were available from the literature and used as informative priors. The developed WB-PBPK model successfully characterized both the typical trends and variability of the available ciprofloxacin plasma concentration data. The WB-PBPK model was thereafter combined with a pharmacokinetic-pharmacodynamic (PKPD) model, developed based on in vitro time-kill data of ciprofloxacin and Escherichia coli to illustrate the potential of this type of approach to predict the time-course of bacterial killing at different sites of infection. The predicted unbound concentration-time profile in extracellular tissue was driving the bacterial killing in the PKPD model and the rate and extent of take-over of mutant bacteria in different tissues were explored. The bacterial killing was predicted to be most efficient in lung and kidney, which correspond well to ciprofloxacin's indications pneumonia and urinary tract infections. Furthermore, a function based on available information on bacterial killing by the immune system in vivo was incorporated. This work demonstrates the development and application of a WB-PBPK-PD model to compare killing of bacteria with different antibiotic susceptibility, of value for drug development and the optimal use of antibiotics .

Early Prediction of 3-month Survival of Patients in Refractory Cardiogenic Shock and Cardiac Arrest on Extracorporeal Life Support

Background:

Extracorporeal life support (ECLS) holds the promise of significant improvement of the survival of patient in refractory cardiogenic shock (CS) or cardiac arrest (CA). Nevertheless, it remains to be shown to which extent these highly invasive supportive techniques could improve long-term patient's outcome.

Methods:

The outcomes of 82 adult ECLS patients at our institution between January 2012 and December 2013 were retrospectively analyzed.

Results:

Patients were essentially men (64.7%) and are 54 years old. Preexisting ischemic (53.7%) and dilated cardiomyopathy (14.6%) were frequent. ECLS indications were shared equally between CA and CS. ECLS-specific adverse effects as hemorrhage (30%) and infection (50%) were frequent. ECLS was effective for 43 patients (54%) with recovery for 35 (43%), 5 (6%) heart transplant, and 3 (4%) left ventricular assist device support. Mortality rate at 30 days was 59.8%, but long-term and 3-month survival rates were similar of 31.7%. Initial plasma lactate levels >5.3 mmol/L and glomerular filtration rate <43 ml/min/1.73 m² were significantly associated with 3-month mortality (risk ratio [RR] 2.58 [1.21–5.48]; P = 0.014; RR 2.10 [1.1–4]; P = 0.024, respectively). Long-term follow-up had shown patients paucisymptomatic (64% New York Heart Association 1–2) and autonomic (activities of daily living [ADL] score 6 ± 1.5).

Conclusion:

In case of refractory CA or CS, lactates and renal function at ECLS initiation could serve as outcome predictor for risk stratification and ECLS indication.

Sepsis modeling in mice: ligation length is a major severity factor in cecal ligation and puncture

Background

The cecal ligation and puncture (CLP) model, a gold standard in sepsis research, is associated with an important variability in mortality. While the number of punctures and needle size is well described in CLP animal studies, the length of cecal ligation is often not. The relationship between cecal ligation and survival in mice is briefly reported in the literature; therefore, we devised an investigation in mice of the consequences of three standardized cecal ligation lengths on mortality and the severity of the ensued sepsis.

Methods

Male C57BL/6J mice underwent standardized CLP. The cecum was ligated at 5, 20, or 100 % of its total length and further perforated by a single 20-G puncture. Mortality was analyzed. We assessed blood lactate, serum creatinine levels, and serum cytokines (TNF-α, IL-1β, IL-6, and IL-10) after procedure in a control group and in ligated mice.

Results

Mortality was directly related to ligation length: median survival was 24 h for the “100 %” group and 44 h for the “20 %” group. Blood lactate increased proportionally with the ligation length. At 6 h post-procedure, pro-inflammatory cytokines significantly increased in the ligated group with significantly higher serum levels of IL-6 in the 100 % group compared to the other ligated groups. The 20 % group exhibited the characteristics of septic shock with hypotension below 65 mmHg, pro-inflammatory balance, organ dysfunction, and hyperlactatemia.

Conclusions

Cecal ligation length appears to be a major limiting factor in the mouse CLP model. Thus, this experimental model should be performed with high consistency in future protocol designs.

The Doppler renal resistive index for early detection of acute kidney injury after hip fracture

BACKGROUND

Postoperative acute kidney injury (AKI) is linked to an increase in morbidity and mortality, particularly in elderly populations. This study's aim was to assess the accuracy of the Doppler renal resistive index (RI) in detecting AKI at an early stage after hip fracture surgery.

METHODS

This prospective single-centre study included 48 patients suffering hip fractures requiring surgery and who presented risk factors for the development of AKI. The RI was calculated preoperatively and postoperatively in patients without pain and with haemodynamic and respiratory stability. The occurrence of AKI was determined by measurements of serum creatinine according to AKIN criteria.

RESULTS

Twenty-nine patients (60%) developed AKI during the first five postoperative days, without need for dialysis. The RI was increased in patients who developed postoperative AKI 0.68 (0.67-0.71) vs. 0.72 (0.7-0.73); P=0.014 for the preoperative index; and 0.6 (0.58-0.68) vs. 0.74 (0.71-0.76); P<0.0001 for the postoperative index. A postoperative index superior or equal to 0.706 is a marker for the early detection of AKI with a high sensitivity and a high specificity (76% and 89%, respectively).

CONCLUSION

The calculation of the RI during the perioperative periods of hip fracture surgery predicts early and effectively the postoperative occurrence of AKI, thus allowing treatment to be anticipated so as to improve patient prognosis.

Screening of patients with augmented renal clearance in ICU: taking into account the CKD-EPI equation, the age, and the cause of admission

Background

In ICU patients with normal serum creatinine (SCr), a state of increased renal drug excretion has been described (creatinine clearance ≥130 ml/min/1.73 m²), and named augmented renal clearance (ARC). In ICU patients, the accuracy of GFR estimates is insufficient. However, in clinical practice, the physician has not at one’s disposal patient measured creatinine clearance (CrCl) when prescribing. The primary objective of this study was to assess the accuracy of 4 formulas to estimate GFR (Cockcroft-Gault (CG), Robert, sMDRD, and CKD-EPI formulas) with other covariates to detect ARC in ICU patients.

Methods

We enroled 360 consecutive ICU patients with normal SCr in this prospective observational study conducted in a primary teaching hospital. Comparisons between CrCl values and 4 estimated GFR (eGFR) formulas were estimated.

Results

In these 360 patients, ARC was observed in 33 % of patients most of them trauma. Individual predictive values of equations were poor and the phenomenon increased in ARC subgroup. CG and CKD-EPI were more accurate to detect an ARC. Multivariable analysis showed that the best-fitting model included 3 factors independently correlated to ARC: trauma patients, cut-off values of age ≤58 years, and CKD-EPI more than 108 ml/min/1.73 m².

Conclusions

In ICU patients with normal SCr, eGFR formulas are imprecise in assessing CrCl. If measured CrCl must be ideally used to detect modifications of the renal function, in clinical practice, age, reason for admission, and CKD-EPI could be used as screening tool to identify ARC.

Patient-ventilator synchrony in Neurally Adjusted Ventilatory Assist (NAVA) and Pressure Support Ventilation (PSV): a prospective observational study

Background

Weaning from mechanical ventilation is associated with the presence of asynchronies between the patient and the ventilator. The main objective of the present study was to demonstrate a decrease in the total number of patient-ventilator asynchronies in invasively ventilated patients for whom difficulty in weaning is expected by comparing neurally adjusted ventilatory assist (NAVA) and pressure support ventilation (PSV) ventilatory modes.

Methods

We performed a prospective, non-randomized, non-interventional, single-center study. Thirty patients were included in the study. Each patient included in the study benefited in an unpredictable way from both modes of ventilation, NAVA or PSV. Patients were successively ventilated for 23 h in NAVA or in PSV, and then they were ventilated for another 23 h in the other mode. Demographic, biological and ventilatory data were collected during this period. The two modes of ventilatory support were compared using the non-parametric Wilcoxon test after checking for normal distribution by the Kolmogorov–Smirnov test. The groups were compared using the chi-square test.

Results

The median level of support was 12.5 cmH₂O (4–20 cmH₂O) in PSV and 0.8 cmH₂O/μvolts (0.2–3 cmH₂O/μvolts) in NAVA. The total number of asynchronies per minute in NAVA was lower than that in PSV (0.46 vs 1, p < 0.001). The asynchrony index was also reduced in NAVA compared with PSV (1.73 vs 3.36, p < 0.001). In NAVA, the percentage of ineffective efforts (0.77 vs 0.94, p = 0.036) and the percentage of auto-triggering were lower compared with PSV (0.19 vs 0.71, p = 0.038). However, there was a higher percentage of double triggering in NAVA compared with PSV (0.76 vs 0.71, p = 0.046).

Conclusion

The total number of asynchronies in NAVA is lower than that in PSV. This finding reflects improved patient-ventilator interaction in NAVA compared with the PSV mode, which is consistent with previous studies. Our study is the first to analyze patient-ventilator asynchronies in NAVA and PSV on such an important duration. The decrease in the number of asynchronies in NAVA is due to reduced ineffective efforts and auto-triggering.

Treatment of intra-abdominal haemorrhagic shock by Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA)

PURPOSE

Haemorrhagic shock is commonly encountered in the emergency room and is associated with high morbidity and mortality. For intra-thoracic and intra-abdominal bleeding, treatment usually requires either surgery or an interventional radiologic procedure. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) has already been described for pelvic fractures and intra-abdominal haemorrhages. In this case report, we present the use of REBOA in a patient admitted for haemorrhagic shock due to a ruptured splenic artery aneurysm.

CASE REPORT

We describe the case of a 35-year-old male with suspected massive pulmonary embolism. Prior to diagnostic confirmation by CT-scan, the patient suffered several cardiac arrests. CT-scan revealed a massive haemoperitoneum secondary to a ruptured aneurysm of the splenic artery. Because of refractory hypotension despite maximal conventional therapy, we used REBOA before patient transfer to the operating room for splenectomy.

CONCLUSIONS

This case underlines the feasibility of REBOA and discusses its role in uncontrollable intra-abdominal haemorrhagic shock.

Estimation of glomerular filtration rate to adjust vancomycin dosage in critically ill patients: superiority of the Chronic Kidney Disease Epidemiology Collaboration equation?

The purpose of this study was to determine the best estimate of glomerular filtration rate (GFR) to adjust vancomycin (VAN) dosage in critically ill patients. Seventy-eight adult intensive care unit patients received a 15 mg/kg loading dose of VAN plus a 30 mg/kg/day continuous infusion. Steady-state concentration was measured 48 hours later and the dose was adjusted to obtain a target concentration ranging from 20 to 25 mg/l. GFR was estimated by measured creatinine clearance (CLCR), Cockcroft, Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations. The required dose providing the target concentration was 36±17 mg/kg/day. The first dosage had to be increased in 51% of all patients and in 84% of trauma patients (highest GFR), but had to be decreased in 17% of patients. The closest relationship between clearances of vancomycin was observed with CKD-EPI to GFR. The correlation between clearances of vancomycin and measured CLCR was significant but was rather poor with Cockcroft and Modification of Diet in Renal Disease equation. On the Bland and Altman plots, measured CLCR provided a lower bias but a larger confidence interval and a weaker precision than CKD-EPI. For VAN dose adjustments in intensive care unit patients, Cockcroft formula and Modification of Diet in Renal Disease should be used with caution. In clinical practice, the physician does not have at their disposal the patient's measured CLCR when prescribing. The CKD-EPI appears to be the best predictor of clearances of vancomycin for calculation of a therapeutic VAN regimen.

Pharmacodynamics of cisatracurium in the intensive care unit: an observational study

Background

Data from previous studies indicate that optimal conditions for intubation are met 120 seconds after administration of 0.15 mg.kg^-1 cisatracurium (ED95 × 3) following the induction of anesthesia. The aim of this study was to compare the doses required for complete paralysis after induction of anesthesia in ICU patients with the dose used in patients undergoing elective surgery.

Methods

Seventeen ICU patients undergoing percutaneous tracheostomy and 17 patients undergoing an elective surgical procedure under muscle relaxation were included. In both groups, an initial intravenous bolus of cisatracurium besylate was given at a dose of 0.15 mg.kg^-1 followed by repeated boluses of 0.03 mg.kg^-1 every four minutes. The objective was to obtain no response to the train-of-four (TOF). The contractile response of the corrugator supercilii muscle was monitored every minute by observing the TOF in response to a peripheral nerve stimulator with a constant current set to 60 mA.

Results

After the initial dose of cisatracurium, none of ICU patients (0/17) versus 15/17 of the elective surgery patients were completely paralyzed (P < 0.0001). There was a delay in the onset of neuromuscular blockade among the ICU patients. The cumulative doses of cisatracurium were significantly higher in the ICU group with 38 ± 14 mg (that is, 10 ± 4.7 ED95) versus 11 ± 2 mg (that is, 3 ± 0.3 ED95) in the elective surgery group (P < 0.0001).

Conclusion

The dosing of cisatracrurium for ICU patients, which is based on the dose recommended for elective anesthesia, is unsuitable because the onset is too slow. This phenomenon is probably caused by changes in the pharmacodynamics and pharmacokinetics. These data suggest that neuromuscular monitoring should be used in the ICU.

Noninvasive assessment of hemodynamic response to a fluid challenge using femoral Doppler in critically ill ventilated patients

PURPOSE

The purpose of the study is to determine if femoral artery blood flow Doppler parameters can assess cardiac response to a fluid challenge (FC).

MATERIALS AND METHODS

We prospectively recorded in 52 critically ill ventilated patients' velocity time integral variation (%VTIf) and maximal systolic velocity variation (%Vfmax) derived from femoral Doppler analysis and aortic velocity time integral variation registered on transthoracic echocardiography before and after an FC of 500-mL saline.

RESULTS

According to Pearson coefficient, %Vfmax and %VTIf were found to be positively correlated with aortic velocity time integral variation (r(2) = 0.46 and 0.51, respectively; P < .0001) and were significantly different between responder patients and nonresponders (11% ± 3.4% vs 5.9% ± 4.3% and 14.9% ± 4.2% vs 5.5% ± 5.5%, respectively; P < .0001). Increase of %VTIf 10% or higher and %Vfmax 7% or higher after an FC showed a sensitivity of 80% and 84%, a specificity of 85% and 73%, and an area under the curve of 0.905 and 0.851, respectively, for discriminating responder and nonresponder patients.

CONCLUSION

Variation of femoral Doppler parameters before and after FC mirrors cardiac response to fluid loading. This tool could be considered as an alternative to transthoracic echocardiography in case of poor thoracic insonation.

Ceftazidime dosage regimen in intensive care unit patients: from a population pharmacokinetic approach to clinical practice via Monte Carlo simulations

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

The large variability in drug pharmacokinetic disposition has already been described in ICU patients leading to important variations in drugs concentrations. The usual recommended dosage of ceftazidime is not adapted for all ICU situations and ceftazidime should be monitored closely. New recommendations have to be given for some specific cases.

WHAT THIS STUDY ADDS

Our results propose individual therapeutic drug monitoring taking into account: For the patient: the reason of admission in the ICU, the mechanical ventilation status and the creatinine clearance calculated by the modified diet in renal disease (MDRD). • For the antibiotics: the lung distribution, the minimal inhibitory concentration (MIC) of the strain to eradicate and the potential toxicity. AIM To predict the ceftazidime dosage regimen as a function of the glomerular filtration rate expressed by the modification of the diet in renal disease (MDRD), reason for admission and mechanical ventilation in intensive care unit (ICU) patients to treat Pseudomonas aeruginosa pneumonia.

METHOD

A published and qualified population pharmacokinetic model was used to perform Monte Carlo simulations of ceftazidime concentrations. The serum target of 40-100 mg l(-1) was defined based on the minimal inhibitory concentration (MIC), the European break point (EBP), the pulmonary drug diffusion and toxicity. The recommended dosage regimens were based on the maximum percentile of the patients with simulated steady state concentrations reaching the target.

RESULTS

Steady-state was reached at 72 h whatever the MDRD. The simulations of serum concentrations generated higher percentiles of the population reaching the target after continuous administration. We recommend a 4 g continuous dose after the usual 2 g loading dose for patients with MDRD from 10 to 30 ml min(-1) , 6 g for MDRD between 40 and 80 ml min(-1) , 8 g for MDRD from 90 to 110 ml min(-1) , 10 g for MDRD from 120 to 190 ml min(-1) and 12 g day(-1) for patients with MDRD higher than 200 ml min(-1) .

CONCLUSION

Our study demonstrated that in ICU patients for a given MDRD, steady-state takes longer to reach in polytrauma patients than in patients with medical or post surgery reasons for admission. Continuous infusion ensures that a higher percentage of patients reaches the target than the same dose given by discontinuous administration and this only depends on MDRD.

Optimizing ciprofloxacin dosing in intensive care unit patients through the use of population pharmacokinetic-pharmacodynamic analysis and Monte Carlo simulations

OBJECTIVES

To explore different ciprofloxacin dosage regimens for the treatment of intensive care unit (ICU) patients with respect to clinical outcome and the development of bacterial resistance for the major Gram-negative pathogens.

METHODS

A population pharmacokinetic model was first developed on ciprofloxacin serum concentrations obtained in 102 ICU patients. Then, based on this model, pharmacokinetic-pharmacodynamic Monte Carlo simulations (MCSs) were carried out to explore the appropriateness of different ciprofloxacin dosage regimens in ICU patients. The defined targets were free AUC(24)/MIC ≥90 h (as a predictor of clinical outcome) and T(MSW) ≤20% (as a predictor of selecting resistance), where T(MSW) is the time spent within the mutant selection window over 24 h. Two simulation trials were conducted: Trial 1 took into account the whole MIC distribution for each causative pathogen in line with empirical antibiotherapy; Trial 2 used MIC breakpoints given by the Antibiogram Committee of the French Microbiology Society in order to treat the 'worst-case' scenario.

RESULTS

Trial 1 showed that for Pseudomonas aeruginosa and Acinetobacter baumannii, the common dosage regimens of 400 mg twice or three times a day did not achieve the desired target attainment rates (TARs) with respect to T(MSW), while suboptimal TARs were found for AUC(24)/MIC. Trial 2 showed that ≤ 18% of patients reached the target of T(MSW) ≤ 20% for MIC breakpoints of 0.5 and 1 mg/L, regardless of the administered dose.

CONCLUSIONS

Based on the mutant selection window concept, our simulations truly question the use of ciprofloxacin for the treatment of P. aeruginosa and A. baumannii infections in ICU patients due to the potential for developing resistance.

Tobramycin disposition in ICU patients receiving a once daily regimen: population approach and dosage simulations

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT? It is well known that tobramycin given as an once daily dose according to the usual recommendations needs therapeutic drug monitoring by measurement of peak and trough concentrations. In the literature, there are only few published studies on the population pharmacokinetics of once daily tobramycin in critically ill patients. Glomerular filtration rate and bodyweight were identified as covariates contributing to the inter-individual variability in the disposition of aminoglycosides. The study, by Peris-Marti et al. [24], only evaluated the pharmacodynamic effectiveness of a 4 mg kg(-1) dose of tobramycin given once daily in critically ill patients. The authors concluded with a simulation showing that for a theoretical MIC of 1 or 2 mg l(-1) , a 7 mg kg(-1) dose was required.

WHAT THIS STUDY ADDS

Our results confirm the high variability of tobramycin disposition in intensive care patients and consequently the possible lack of effectiveness. By using a population pharmacokinetic approach, two explicative covariates (height and Cockcroft creatinine clearance) added to a two-compartment model with proportional error, explained much of the inter-individual variability of tobramycin disposition in the critically ill patient population. In a median ICU patient, simulations were performed at various dosage regimens and peak and AUC pharmacodynamic targets could not be reached simultaneously in more than 45% of the ICU patient population. Drug monitoring is required to manage efficacy and toxicity.

AIM

The aim of this study was to evaluate the disposition of tobramycin (TOB) in critically ill patients (ICU) by a population pharmacokinetic approach, to determine the covariates involved, and to simulate tobramycin dosage regimens.

METHODS

Forty-nine adult ICU patients received TOB (5 mg kg(-1) ) once daily. NonMem modelling was performed on 32 patients. The 17 other patients were used for the qualification process by normalized prediction distribution error. Then Monte Carlo simulations (MCS) were performed.

RESULTS

A two-compartment model with a proportional error best fitted the data. TOB total clearance (CL(TOB) ) was significantly correlated with Cockcroft creatinine clearance (COCK) and height. TOB clearance was 4.8 ± 1.9 l h(-1) (range 1.22-8.95), the volume of distribution of the central compartment was 24.7 ± 3.7 l (range 17.34-32.83) and that of the peripheral compartment and the inter-compartmental clearance were 30.6 l and 4.74 l h(-1) , respectively. Only 29% of the patients presented a target AUC between 80 and 125 mg l(-1) h and 61% were lower than 80 mg l(-1)  h. After considering COCK and height, MCS showed that only 50% of the population could achieve the target AUC for the 375 and 400 mg dosages.

CONCLUSION

Even after taking into account COCK and height, for strains with an MIC ≤ 1 mg l(-1) , MCS doses evidenced that peak and AUC pharmacodynamic targets could not be reached simultaneously in more than 45% of the ICU patient population. Combination therapy in addition to drug monitoring are required to manage efficacy and toxicity.

Ciprofloxacin use in critically ill patients: pharmacokinetic and pharmacodynamic approaches

The objective of this study was to evaluate the properties of ciprofloxacin in intensive care patients using a population approach. Seventy patients received ciprofloxacin. On Day 1, three to eight blood samples were taken over a 12-h period. Peak drug concentration (Cmax) and 24-h area under the concentration-time curve (AUC) were compared with the French breakpoint defining antibiotic susceptibility. A population pharmacokinetic modelling approach was then carried out. A two-compartment open model with a proportional error model best fitted the data. A relationship between the elimination constant rate and the Cockcroft creatinine clearance was found. Ciprofloxacin clearance was 13.6+/-5.8L/h, the volume of distribution was 62.0+/-10.7 L and the ciprofloxacin half-life was 3.7+/-1.8h. When the minimum inhibitory concentration (MIC) was equal to 1mg/L the inhibitory ratio (IR) was > or = 8 in only 10.8% of cases, and the AUC/MIC ratio (AUIC) was 42.0+/-36. In conclusion, this study highlights that the Cockcroft clearance significantly influences ciprofloxacin elimination. Target plasma concentrations for ciprofloxacin, the IR and AUIC were rarely reached with a standard dosing regimen. In critically ill patients, the observed pharmacokinetic variability is mainly responsible for the overly frequent low concentrations of ciprofloxacin, emphasising the need for therapeutic monitoring.

Intermittent administration of ceftazidime to burns patients: influence of glomerular filtration

OBJECTIVE

The pharmacokinetics of ceftazidime, the antibiotic of choice for treating acute P. aeruginosa infections, may be modified in burns patients. The aim of this study was to identify the factors causing variations in the serum antibiotic concentrations in bums patients.

METHODS

30 patients with serious burns were randomly divided into two groups. Group 1 received a dose of ceftazidime of 2 x 3 g/24 hours. The second group received the same dose but divided into 6 administrations. Blood samples were taken at 24 (M1) and 48 hours (M2) after the start of treatment and the peak and trough serum concentrations of ceftazidime measured by HPLC. Depending on the results, frequency and/or dose was modified to obtain trough concentrations (Cmin) equal to 16 mg/l, i.e. 4 times the MIC. Either the same dose was maintained, but mostly divided up, or it was increased to 1 g x 8 administrations or it was decreased to 1 g x 4 or 1 g x 3. The serum concentrations of ceftazidime obtained were analyzed taking into account the characteristics of the burns patients (multivariate correlation).

RESULTS

From the first sample (M1) Cmin was lower than the target concentration in 50% of the patients in Group 1 and 20% in Group 2. The modification of the dosing regimen put into place after the first analysis, led to the patients being further divided into four groups before the second blood sampling. Finally, 5 patients ended up in Group 1. In all patients and for all administration times, a negative correlation was found between Cmin and the creatinine clearance, calculated by using Cockcroft's formula.

CONCLUSION

This study highlights the peculiarities of ceftazidime pharmacokinetics seen in burns patients with high interindividual variability. Based on Cmin monitoring and a predefined therapeutic range, dose adjustment was often required. Ceftazidime clearance is correlated with creatinine clearance (Cockcroft's formula), suggesting that this parameter could be used for a priori or a posteriori dose individualization. To respect the summary of the product characteristics (SPC) and reduce the variability in trough concentrations, the dose should be fractionated (1 g x 6) over a 24-hour period or even given as a continuous infusion. Trough concentrations must be evaluated to adapt the dosage regimen to attain target concentrations of 4 x the MIC.

Assessment of renal function in clinical practice at the bedside of burn patients

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

* In burn patients it has been shown ([2]), that there is a correlation between the creatinine clearance (CL(CR)) and the clearance of inulin. * The CL(CR) has never been studied in burn patients who have normal serum creatinine. * The Robert, Kirkpatrick and sMDRD formulae have never been evaluated in burn patients.

WHAT THIS STUDY ADDS

* Despite burn patients having normal serum creatinine concentrations, the study showed that there are large variations in CL(CR) which cannot be detected by single serum creatinine measurements, and which have important implications for drug therapy. * It showed that the formulae currently used to calculate creatinine clearance on the basis of serum creatinine are inadequate for use in burn patients, and they should be abandoned in favour of direct measurement from a 24 h urine collection.

AIMS

The aim of this study was to evaluate whether the renal function of burn patients could be correctly assessed using a single serum creatinine measurement, within normal limits, and three prediction equations of glomerular filtration taking into account, serum creatinine, age, weight and sex.

METHODS

This was a prospective study comprising 36 adult burn patients with a serum creatinine <120 micromol l(-1), within the second or third week following the burn injury. Renal function was assessed using serum creatinine, 24 h urinary CL(CR), and the Cockcroft-Gault, Robert, Kirkpatrick and simplified MDRD equations.

RESULTS

Despite normal serum creatinine concentrations in all patients, a significant number had a decreased CL(CR). The urinary CL(CR) was <80 ml(-1) min(-1) 1.73 m(-2) in nine patients (25%), and <60 ml(-1) min(-1) 1.73 m(-2) in five patients (14%). Between the groups having a CL(CR) lower or greater than 80 ml(-1) min(-1) 1.73 m(-2) there were no differences in gender, burn indices, percentage of mechanically ventilated patients or length of hospital stay, but a difference in age. The highest CL(CR) (>140 ml(-1) min(-1) 1.73 m(-2)) was found in 13 patients younger than 40 years. Regression analysis, residual and Bland-Altman plots revealed that neither the Cockcroft-Gault, Robert, Kirkpatrick nor sMDRD equations were specific enough for the assessment of renal function.

CONCLUSIONS

In burn patients with normal serum creatinine during the hypermetabolic phase, serum creatinine and creatine based predictive equations are imprecise in assessing renal function.

Influence of renal function on trough serum concentrations of piperacillin in intensive care unit patients

OBJECTIVE

To explore the effects of renal function estimated by measured creatinine clearance (Cl(CR)) on trough serum concentration (C(min)) of piperacillin given to critically ill patients.

DESIGN

Prospective observational study.

SETTING

An intensive care unit and research ward in a university hospital.

PATIENTS

Seventy critically ill patients, including 22 with severe trauma.

INTERVENTIONS

All subjects received an intravenous infusion of piperacillin 4 g three times (n = 61) or four times (n = 9) per day. Piperacillin C(min) values were determined 24 h after treatment started and compared to the French breakpoint defining antibiotic susceptibility against Enterobacteriaceae (8 mg/l) or Pseudomonas sp. (16 mg/l).

RESULTS

Median (range) piperacillin C(min) was 11.9 (< 1-156.3) mg/l, with a great variability among patients. Although the median value was close to the breakpoints, sub-therapeutic plasma levels were frequently observed. Piperacillin C(min) was lower than the breakpoint for Enterobacteriaceae in 37% of patients, and lower than the breakpoint for P. aeruginosa in 67% of them. A strong relationship was observed between piperacillin C(min) and Cl(CR): the higher the Cl(CR,) the lower the piperacillin C(min )in serum. For patients with a Cl(CR) < 50 ml/min, enough piperacillin C(min) was achieved in most patients with 12 g piperacillin per day. For patients with higher Cl(CR) values, a piperacillin daily dose of 16 g or more may be warranted.

CONCLUSIONS

In critically ill patients, therapeutic monitoring must be part of the routine, and knowledge of Cl(CR) value may be useful for the choice of adequate initial piperacillin dosing.

Increased amikacin dosage requirements in burn patients receiving a once-daily regimen

Altered pharmacokinetics in burn patients may affect antibiotic plasma concentrations. Typical once-daily dosing (ODD) of 15 mg/kg amikacin (AMK) in burn patients does not always produce peak concentrations (C(max)) reaching the therapeutic objective of six to eight times the minimal inhibitory concentration (MIC). We recorded plasma concentrations following administration of 20 mg/kg AMK in burn patients and studied factors affecting pharmacokinetics. Mean C(max) was 48.3+/-10.8 mg/L and the C(max)/MIC ratio was 6+/-1.35. Statistical analysis demonstrated a relationship between C(max) and the area of the burn and Unit Burn Standard, and between AMK clearance and creatinine clearance (Cl(CR)). We conclude that ODD regimens of AMK in patients with burns >15% body surface area and/or with Cl(CR) >120 mL/min could require doses >20 mg/kg to reach adequate C(max). In all cases, patient therapeutic drug monitoring is essential to ensure the safe usage of these dosing recommendations.

Retrospective analysis of multidrug-resistant Acinetobacter baumannii strains isolated during a 4-year period in a university hospital

OBJECTIVE

To describe the epidemiology of Acinetobacter baumannii infection during 2000-2003 and to determine whether the multidrug-resistant strains were already present in our Toulouse hospital before the 2003 French national outbreak.

DESIGN

Descriptive molecular and clinical epidemiologic study of A. baumannii isolates using a combination of antibiotyping and pulsed-field gel electrophoresis (PFGE).

SETTING

A 1,000-bed university hospital in Toulouse, France.

METHODS

All clinical samples that had tested positive for A. baumannii between January 1, 2000, and December 31, 2003, were collected. Multidrug-resistant isolates of A. baumannii were then submitted to PFGE, and clinical characteristics of the source patients were noted.

RESULTS

A total of 1,277 A. baumannii samples were identified, 791 of which had not been previously identified; 148 were positive for multidrug-resistant strains. These strains were more likely to have been isolated in the intensive care unit (ICU) than were susceptible strains (P<.001; relative hazard, 3.77). The positive clinical samples were of various types (eg, nonprotected respiratory samples [43%] and blood [5%]), but no difference in type of source was seen between resistant and susceptible strains. A simultaneous analysis of pulsotypes and antibiotypes proved that the outbreak in the ICU in 2003 could be linked to an initially endemic clone that had been isolated in 2001. Furthermore, a second clone responsible for an extended-spectrum beta -lactamase phenotype was sporadically present in our institution. Although the strains isolated in the burn unit were also genetically related one to another, the specific responsible clone only appeared in 2003.

CONCLUSION

Several multidrug-resistant clones can coexist endemically for several years and can be detected during an outbreak by close survey of epidemic sources.

Risk of emergence of Pseudomonas aeruginosa resistance to β-lactam antibiotics in intensive care units

OBJECTIVE

The emergence of Pseudomonas aeruginosa resistance to antimicrobial drugs is frequent in intensive care units and may be correlated with the use of some specific drugs. The purpose of our study was to identify a relationship between the use of various beta-lactam antibiotics and the emergence of resistance and to characterize the mechanism of resistance involved.

DESIGN

We conducted an open prospective study over a 3-yr period by including all patients in whom P. aeruginosa had been isolated from one or more specimens: bronchial aspiration, blood cultures, catheters, and urinary cultures.

SETTING

General intensive care unit.

PATIENTS

One hundred and thirty-two intensive care unit patients.

INTERVENTIONS

The antibiotics studied were amoxiclav, piperacillin-tazobactam, cefotaxime, ceftazidime, cefepim, and imipenem. The mechanisms of resistance studied were production of penicillinase or cephalosporinase, nonenzymatic mechanisms, and loss of porin OprD2. Analysis was performed using Cox proportional-hazard regression with time-dependant variables.

MEASUREMENTS AND MAIN RESULTS

Forty-two strains became resistant, 30 to one antibiotic, nine to two, and three to three, leading to the study of 57 resistant strains. Imipenem (hazard ratio 7.8; 95% confidence interval, 3.4-18.1), piperacillin-tazobactam (hazard ratio 3.9; 95% confidence interval, 1.3-11.9), and cefotaxim (hazard ratio 9.3; 95% confidence interval, 2.9-30.2) were strongly linked to the emergence of resistance. The use of imipenem (p<.0001) was associated with the loss of porin OprD2. Thirty-six strains from nine patients, assayed by pulsed-field gel electrophoresis, showed that for any one patient, all the strains were genetically related.

CONCLUSIONS

Our results show that there is a high risk of the emergence of drug resistance during treatment with cefotaxime, imipenem, and piperacillin-tazobactam. This has to be taken into account in the therapeutic choice and in the patient's surveillance.