Michèle Genestal

Predictive value of abdominal obesity vs. body mass index for determining risk of intensive care unit mortality.

Objective:To explore whether sagittal abdominal diameter as a marker of abdominal obesity is a risk factor for death and morbidity in patients in the intensive care unit and a better outcome determinant for obese patients than body mass index. Design:Prospective, observational study from April 2008 to January 2009. Setting:Two general intensive care units, both in Toulouse University Hospitals, France. Participants:All adult patients admitted in the two intensive care units except those routinely discharged within 48 hrs or those having conditions with possible effect on anthropometric indices. Interventions:Measurement of the sagittal abdominal diameter at admission allowed us to divide the studied population into abdominally obese, underweight, and control groups. Measurements and Results:The primary outcome measure was mortality in the intensive care unit until day 60 after admission. Secondary outcomes were morbidity and length of stay in the intensive care unit. Among 503 patients admitted, 403 were included. At admission, age, diabetes, dyslipidemia, hypertension, Simplified Acute Physiology Score II, and McCabe scores were higher in the abdominally obese group (n = 109) than in the control group (n = 277). The rate of death was higher in the abdominally obese group compared to control (44% vs. 25.3%; p < .01). After adjustment for age, simplified acute physiology score, II and McCabe score, a multivariate analysis showed an increased risk of death in the abdominally obese group (adjusted odds ratio, 2.12; 95% confidence interval, 1.25–3.60). A body mass index >30 kg/m2 was not an independent risk factor for death. During the stay in the intensive care unit, incidence of acute renal failure and abdominal compartment syndrome were higher in the abdominally obese group. Conclusion:A high sagittal abdominal diameter, and not a high body mass index, is an independent risk factor of death in critically ill patients.

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

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

Stroke output variations calculated by esophageal Doppler is a reliable predictor of fluid response

ObjectiveEsophageal Doppler allows continuous monitoring of stroke volume index (SVI) and corrected flow time (FTc). We hypothesized that variations in stroke output index SOI (SVI/FTc) during volume expansion can predict the hemodynamic response to subsequent fluid loading better than the static values.Design and settingProspective study in the intensive care unit of a university hospital.PatientsFifty-one patients with circulatory failure were monitored by esophageal Doppler.InterventionsPatients who responded to a first fluid challenge received a second one. Patients who responded to both were classified as responders-responders, and those who did not respond to the second as responders-nonresponders. In these two groups we compared ΔSVI, ΔFTc, and ΔSOI during each fluid challenge and also static values at the end of each fluid challenge.Measurements and resultsAfter the first fluid challenge ΔSOI and ΔSVI were significantly higher in patients who responded to subsequent volume expansion than in patients who no longer responded. ROC curves showed that ΔSOI was a better predictor of fluid responsiveness than ΔSVI. During volume expansion a ΔSOI value of 11% discriminated between responders and nonresponders to subsequent volume expansion with a sensitivity of 91% and a specificity of 97%. There was no significant difference between the two groups for FTc value at the end of first fluid challenge.ConclusionsAnalysis of ΔSOI during fluid challenge predicts response to subsequent fluid challenge and FTc is not a reliable indicator of cardiac preload.

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

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

Relative accuracy of arterial and capillary glucose meter measurements in critically ill patients

AIM As optimizing glucose control in critically ill patients remains a challenge for intensive-care physicians, this study aimed to determine the accuracy of glucose measurements. METHODS The accuracy of capillary and arterial blood glucose meter measurements was compared with central laboratory arterial glucose measurements; the factors associated with inaccurate measures were also determined. RESULTS Altogether, 302 samples from 75 patients were assessed. Mean glucose levels were 126±52 mg/dL for capillary measurements, 133±50 mg/dL for arterial measurements and 143±54 mg/dL for serum glucose laboratory measurements. Compliance with the ISO 15197 guidelines was observed in 74.8% of the capillary samples and 88.7% of the arterial samples. However, all measurements by glucose meter (with either capillary or arterial samples) led to underestimations of serum glucose. CONCLUSION In critically ill patients, glucose measurements from capillary and arterial blood by glucose meter are inaccurate, and can potentially lead to inappropriate use of insulin-infusion protocols and failure to achieve glycaemic targets.

Alteration of plasma phospholipid fatty acid profile in patients with septic shock.

In septic shock patients, alterations of plasma phospholipid fatty acid profile have never been described. The purpose of this monocentric, non-interventional, observational prospective study was to describe this fatty acid profile in the early phase of septic shock in intensive care unit. Thirty-seven adult patients with septic shock were included after the first day of stay in intensive care unit, before any form of artificial nutritional support. Plasma phospholipid fatty acid composition was determined by gas chromatography. All biological data from patients with septic shock were compared with laboratory reference values. Patients presented hypocholesterolemia and hypertriglyceridemia. They had low concentrations of phospholipid fatty acids specifically n-6 and n-3 polyunsaturated fatty acids (PUFAs) with a high n-6/n-3 ratio. Plasma phospholipid PUFA concentrations were strongly correlated with cholesterolemia. PUFAs/SFAs (saturated fatty acids) and PUFAs/MUFAs (monounsaturated fatty acids) ratios were low because of low percentage of n-6 and n-3 PUFAs and high percentage of SFAs and MUFAs. Low levels of plasma long chain PUFAs (≥20 carbons) were significantly associated with mortality at 28th day. In conclusion, plasma phospholipid FA profile of septic patients is very characteristic, close to that of acute respiratory distress syndrome and mortality is associated with long chain PUFA decrease. This profile could be explained by numerous non-exclusive physio-pathological processes 1) an activation of hepatic de novo lipogenesis that could contribute to hepatic steatosis, 2) an elevated adipose tissue lipolysis, 3) an increased free radical attack of FA by oxidative stress, 4) an over-production of inflammatory lipid mediators.

An unusual cause of severe lactic acidosis: cyanide poisoning after bitter almond ingestion

Dear Editor, Although cyanide exists in various alimentary sources like manioc, corn, bitter almonds, peach or apricot kernels, food-related cyanide intoxications are rare [1]. A 58-year-old healthy woman was admitted for sudden headaches, dizziness, vomiting, and generalized seizures. Prehospital medical services found her comatose (Glasgow Coma Score: 5) with bradycardia (30/min) and nonmeasurable blood pressure. She was promptly intubated and received fluids. A brain CT scan was normal. On intensive care unit (ICU) admission, her blood pressure was 80/40 mmHg, heart rate 62/min, SpO2 100% (FiO2: 100%), and temperature 37.0 C. Physical examination, electrocardiogram, and echocardiography were unremarkable. Severe lactic acidosis (arterial pH: 6.59, base deficit: 36.0 mmol/l, anion gap: 33.0 mmol/l, and plasma lactate concentration: 26.0 mmol/l) was assessed without ketosis, osmolar gap, liver or renal dysfunction. Fluids (2,000 ml), norepinephrine (0.5 mg/h), insulin, and sodium bicarbonate were infused. Routine toxicological screening was negative. Blood cyanide concentration was 2.77 mg/l (spectrophotometric method; N \0.2 mg/l; limit of detection: 0.06 mg/l) 6 h after coma onset. Hydroxocobalamin (10 g, 140 mg/kg) was immediately infused, resulting in complete recovery: lactate normalization (within 12 h, Table 1), norepinephrine weaning (20 h), acid/base balance correction (36 h), extubation (day 2), and ICU discharge (day 3). Her husband finally remembered that she had ingested a large quantity of bitter almonds (around 50) from the garden, 2 h before symptom onset. Accidental food-related cyanide poisonings are unusual [1]. Signs are delayed after ingestion, in relation to enzymatic processes producing cyanide in the gut from the ingested cyanogenic glucosides. Cyanide poisoning is rapidly fatal if not promptly treated. Clinical features are not specific, misleading the diagnosis. However, when suspicion is based on compatible circumstances, plasma lactate concentrations C8 mmol/l are an excellent predictor of blood cyanide concentrations C1 mg/l [2]. In our case, despite no relevant anamnesis, cyanide poisoning was suspected because of severe lactic acidosis with coma, hypotension, and bradycardia in the absence of sepsis. Reported symptoms of cyanide poisoning following almond/seed ingestion included headaches, dizziness, sweating, pink cyanosis, coma, seizures, hyperthermia, hypotension, polypnea, bradypnea, hypoglycemia, and lactic acidosis [3, 4]. To our knowledge, hyperlactatemia (pH 7.17, lactate: 14.3 mmol/l) was reported in only one case after ingestion of bitter almonds with laetrile tablets (containing amygdaline) given for alternative cancer treatment [3]. The present case is unique for two reasons: the severity of almondinduced lactic acidosis and its dramatic improvement after hydroxocobalamin infusion. Management of cyanide poisoning is based on advanced life support and antidotes. Despite cyanide-induced deficient cell oxygen utilization, increased oxygen delivery (FiO2: 100%) is useful to reactivate mitochondrial enzymes and other oxidative systems. Hydroxocobalamin is an effective and safe antidote binding cyanide on an equimolar ratio to form stable cyanocobalamin, which is excreted in urine [5]. Although we should

Intra-abdominal pressure measurement method via the urinary-tube: bedside validation of a biomechanical model integrating urine column height and bladder urinary volume.

Background:The objective of this work was to demonstrate the possibility of accurately measuring intra-abdominal pressure (IAP) by using a common urine drainage bag (U-Tube) as a hydrostatic column of measurement. This has been done by integrating urine column height (h) and bladder urinary volume (BUV) in the IAP measurement method. Method:Seventy-eight newly admitted patients in a 22 bed university hospital intensive care unit (ICU) were studied. Two U-Tube IAP measurement methods were compared with the “Gold-standard” closed-system repeated measurement technique with bladder pressure transducer: U-Tube method I, where h (in cm) alone assesses IAP (in cm H2O) and U-Tube method II, integrating BUV according to a basic biomechanical model of bladder wall compliance to give a more accurate IAP estimation. Results:Correlation rate using linear regression analysis was better between the Gold standard method and method II than method I with R2 = 0.901, P < 0.0001 and R2 = 0.682, P < 0.0001, respectively. For method II, Bland-Altman analysis showed a mean bias of −1.0 ± 0.1 mm Hg (limits of agreement −3.4–1.4, percentage error ±7.7%). Area under the receiver operator characteristics curves to screen intra-abdominal hypertension (IAP ≥12 mm Hg) was significantly greater with method II than with method I: 0.99 versus 0.93, P < 0.05; sensitivity and specificity of method II were 95% and 98%, respectively. Conclusion:By integrating urine column height and BUV in the measurement method, it may be conceivable to screen IAH at the bedside via a U-Tube in ICU; bladder wall compliance should be estimated to avoid the emergence of false-positive subjects due to the possible occurrence of bladder wall compliance alteration before or during the ICU stay.

Use of brain diffusion tensor imaging for the prediction of long-term neurological outcomes in patients after cardiac arrest: a multicentre, international, prospective, observational, cohort study

BACKGROUND Prediction of neurological outcome after cardiac arrest is a major challenge. The aim of this study was to assess whether quantitative whole-brain white matter fractional anisotropy (WWM-FA) measured by diffusion tensor imaging between day 7 and day 28 after cardiac arrest can predict long-term neurological outcome. METHODS This prospective, observational, cohort study (part of the MRI-COMA study) was done in 14 centres in France, Italy, and Belgium. We enrolled patients aged 18 years or older who had been unconscious for at least 7 days after cardiac arrest into the derivation cohort. The following year, we recruited the validation cohort on the same basis. We also recruited a minimum of five healthy volunteers at each centre for the normalisation procedure. WWM-FA values were compared with standard criteria for unfavourable outcome, conventional MRI sequences (fluid-attenuated inversion recovery and diffusion-weighted imaging), and proton magnetic resonance spectroscopy. The primary outcome was the best achieved Glasgow-Pittsburgh Cerebral Performance Categories (CPC) at 6 months, dichotomised as favourable (CPC 1-2) and unfavourable outcome (CPC 3-5). Prognostication performance was assessed by the area under the receiver operating characteristic (ROC) curves and compared between groups. This study was registered with ClinicalTrials.gov, number NCT00577954. FINDINGS Between Oct 1, 2006, and June 30, 2014, 185 patients were enrolled in the derivation cohort, of whom 150 had an interpretable multimodal MRI and were included in the analysis. 33 (22%) patients had a favourable neurological outcome at 6 months. Prognostic accuracy, as quantified by the area under the ROC curve, was significantly higher with the normalised WWM-FA value (area under the ROC curve 0·95, 95% CI 0·91-0·98) than with the standard criteria for unfavourable outcome or other MRI sequences. In a subsequent validation cohort of 50 patients (enrolled between April 1, 2015, and March 31, 2016), a normalised WWM-FA value lower than 0·91, set from the derivation cohort, had a negative predictive value of 71·4% (95% CI 41·9-91·6) and a positive predictive value of 100% (90·0-100), with 89·7% sensitivity (75·8-97·1) and 100% specificity (69·1-100) for the prediction of unfavourable outcome. INTERPRETATION In patients who are unconscious 7 days after cardiac arrest, the normalised WWM-FA value, measured by diffusion tensor imaging, could be used to accurately predict neurological outcome at 6 months. This evidence requires confirmation from future large-scale trials with a strict protocol of withdrawal or limitation-of-care decisions and time window for MRI. FUNDING French Ministry of Health, French National Agency for Research, Italian Ministry of Health, and Regione Lombardia.

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

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