Decrease in pulse pressure and stroke volume variations after mini-fluid challenge accurately predicts fluid responsiveness†.

BACKGROUND: Dynamic indices, such as pulse pressure variation (PPV), are inaccurate predictors of fluid responsiveness in mechanically ventilated patients with low tidal volume. This study aimed to test whether changes in continuous cardiac index (CCI), PPV, and stroke volume variation (SVV) after a mini-fluid challenge (100 ml of fluid during 1 min) could predict fluid responsiveness in these patients. METHODS: We prospectively studied 49 critically ill, deeply sedated, and mechanically ventilated patients (tidal volume <8 ml kg(-1) of ideal body weight) without cardiac arrhythmias, in whom a fluid challenge was indicated because of circulatory failure. The CCI, SVV (PiCCO™; Pulsion), and PPV (MP70™; Philips) were measured before and after 100 ml of colloid infusion during 1 min, and then after the additional infusion of 400 ml during 14 min. Responders were defined as subjects with a ≥15% increase in cardiac index (transpulmonary thermodilution) after the full (500 ml) fluid challenge. Areas under the receiver operating characteristic curves (AUCs) and the grey zones were determined for changes in CCI (ΔCCI100), SVV (ΔSVV100), and PPV (ΔPPV100) after 100 ml fluid challenge. RESULTS: Twenty-two subjects were responders. The ΔCCI100 predicted fluid responsiveness with an AUC of 0.78. The grey zone was large and included 67% of subjects. The ΔSVV100 and ΔPPV100 predicted fluid responsiveness with AUCs of 0.91 and 0.92, respectively. Grey zones were small, including ≤12% of subjects for both indices. CONCLUSIONS: The ΔSVV100 and ΔPPV100 predict fluid responsiveness accurately and better than ΔCCI100 (PiCCO™; Pulsion) in patients with circulatory failure and ventilated with low volumes.

[High flow oxygen via nasal cannula: Palliative care and ethical considerations]. / Oxygénothérapie nasale à haut débit : soins palliatifs et aspects éthiques.

High flow oxygen via nasal cannula (HFO2NC) has become the first-line reference symptomatic treatment for hypoxemic acute respiratory failure. This non-invasive technique can be addressed, as palliative therapeutic care, to frail patients near end-of-life with a do-not-intubate order. A distinction will be made between those with an imminent and inevitable fatal outcome (pallitative end-of-life management) and those with hope for transient clinical remission (meliorative management). This review focuses on the expected physiological benefits and technical benefits/risks incurred by HFO2NC use in this population. Its main purpose is to highlight the ethical principles governing the palliative management of patients in acute respiratory failure with a do-not-intubate order, and to discuss the various elements to be considered when defining the patient's palliative care plan, in a holistic, individual-centered approach.

[The obese patient and acute respiratory failure, a challenge for intensive care]. / Le patient obèse en insuffisance respiratoire aiguë, un défi pour la réanimation.

As a result of the constantly increasing epidemic of obesity, it has become a common problem in the intensive care unit. Morbid obesity has numerous consequences for the respiratory system. It affects both respiratory mechanics and pulmonary gas exchange, and dramatically impacts on the patient's management and outcome. With the potential for causing devastating respiratory complications, the particular anatomical and physiological characteristics of the respiratory system of the morbidly obese subject should be carefully taken into consideration. The present article reviews the management of obese patients in respiratory failure, from noninvasive ventilation to tracheostomy, including postural and technical issues, and explains the physiologically based ventilatory strategy both for NIV and invasive mechanical ventilation up to the weaning from the ventilatory support.

The obesity supine death syndrome (OSDS).

The obesity supine death syndrome refers to a catastrophic cascade of cardiorespiratory complications resulting from the supine positioning of a morbidly obese subject which can ultimately lead to death. It was first described in 1977 in two massively obese patients who were forced to lie down for medical procedures. But surprisingly, despite the current worldwide epidemic of obesity, very few cases have been reported yet. It can be assumed that the syndrome is poorly recognized in clinical practice and may participate in the high rate of unexplained death in morbidly obese patients. Based on the previously published cases and on those we met, this review aims at helping clinicians to early detect at-risk patients, to correctly diagnose this dramatic syndrome and to understand the underlying pathophysiology. More importantly, the main objective is to convince the attending clinicians that they have to do everything in their power to prevent obesity supine death syndrome occurrence by maintaining morbidly obese patients in the sitting or upright position whenever possible. When the syndrome unfortunately occurs, the best therapeutic approach is based on the immediate return to sitting position.

[Severe varicella zoster pneumonia during the course of treatment with azathioprine for Crohn's disease]. / Pneumopathie varicelleuse sévère au cours d'un traitement par azathioprine pour une maladie de Cröhn.

INTRODUCTION: Disseminated varicella zoster infection has only rarely been reported in patients with inflammatory bowel disease, despite the frequent use of azathioprine for this disorder. CASE REPORT: We report the case of an 18-year-old woman who developed severe varicella zoster pneumonia 9 months after starting azathioprine for Crohn's disease. The patient recovered after prompt treatment with acyclovir and discontinuation of the azathioprine. CONCLUSIONS: Strategies concerning the treatment and the prevention of varicella infection in the immunocompromised patient are discussed.

Mathematical coupling of data between global-end diastolic volume index and cardiac index calculated by the PiCCO device: myth or reality?

BACKGROUND: Aim of the study was to investigate whether cardiac index (CI) and global end diastolic volume index (GEDVi) determined from the same thermodilution curve are mathematically coupled during the infusion of an inotropic agent in critically ill patients. METHODS: Seventeen patients were prospectively studied. CI and GEDVi were evaluated in triplicate by the transpulmonary thermodilution technique with the PiCCO system before and 20 to 30 minutes after increases in dobutamine infusion rate. Mixed linear model was used to determine the within-subject correlation coefficient between changes in CI and GEDVi induced by changes in dobutamine infusion rate. RESULTS: Dobutamine administration significantly increased CI by 48±35%, whereas the average increase in GEDVi was only 8.2±12.3% but statistically significant (P<0.0001). The increase of GEDVi in response to dobutamine infusion was unexpected given that dobutamine has no recognized effect on right and left ventricular dimensions. Intriguingly, we observed a significant correlation coefficient, in individual patients, between changes in CI and GEDVi (r=0.58, P=0.002). CONCLUSION: Our study provides evidence that changes in GEDVi are mathematically coupled to changes in CI during dobutamine infusion. Therefore, clinicians using PiCCO device to evaluate GEDVi must be aware of the underlying formula to avoid placing undue reliance on artifactual correlations due to mathematical coupling.