When Does Nutrition Impact Respiratory Function?

Nutrition therapy is an essential aspect of patient care and an important determinant of outcomes in the ICU. Nutrition can impact respiratory function in a myriad of ways. Under- and overfeeding are two well-established ways by which nutrition impinges on respiratory function. Route of feeding, method of feeding, and carbohydrate composition of the diet are also other key factors regarding nutrition that influence outcomes in ICU patients. Recent studies are now elucidating the role of immune therapy in patients with acute respiratory distress syndrome. In the ICU, nutrition dogmas, such as the necessity of checking gastric residual volumes or utilizing full-calorie enteric feeds, as opposed to trophic feeds, are constantly being challenged by innovative clinical studies. Basic research brings the prospect of testing new approaches for ICU patients, such as the use of antioxidants to prevent diaphragm weakness in these patients. In this review article, we evaluate the recent observational and randomized control trials to critically appraise the evidence regarding nutrition in the ICU.     

Ethanol withdrawal increases blood pressure and vascular oxidative stress: a role for angiotensin type 1 receptors

We evaluated the possible mechanisms underlying the oxidative stress induced by ethanol withdrawal. With this purpose, we verified the role of AT₁ receptors in such response. Male Wistar rats were treated with ethanol 3%–9% (vol./vol.) for 21 days. Ethanol withdrawal was induced by abrupt discontinuation of the treatment. Experiments were performed 48 hours after ethanol discontinuation. Increased plasma levels of angiotensin II were detected after ethanol withdrawal. Losartan (10 mg/kg; p.o. gavage), a selective AT₁ receptor antagonist, impeded the increase in blood pressure induced by ethanol withdrawal. Increased lipoperoxidation and superoxide anion (O₂^?) levels were detected in aortas after ethanol withdrawal, and losartan prevented these responses. Decreased hydrogen peroxide and nitrate/nitrite concentration were detected in aortas after ethanol withdrawal, and losartan prevented these effects. Nitrotyrosine immunostaining in the rat aorta was increased after ethanol withdrawal, and AT₁ blockade impeded this response. Increased expression of PKCδ and p47^phox was detected after ethanol withdrawal, and treatment with losartan prevented these responses. Our study provides novel evidence that ethanol withdrawal increases vascular oxidative stress and blood pressure through AT₁-dependent mechanisms. These findings highlight the importance of angiotensin II in ethanol withdrawal–induced increase in blood pressure and vascular oxidative damage.     

One-step real-time PCR assay for detection and quantification of RNA HCV to monitor patients under treatment in Brazil

The Brazilian Public Health Service provides freely αPEG-IFN to treat patients infected with HCV. The primary goal of HCV therapy is the long-term elimination of HCV from the blood to reduce the risk of HCV associated complications and death. Patient viremia affects the treatment duration and response, thus influencing clinical decisions. We developed a high-throughput method to perform the quantification of RNA hepatitis C virus (HCV) virus load in plasma samples to monitor patients under treatment. The method is based on a duplex detection, in a one-step real-time RT-PCR assay and it has been validated according to the rules established by the official Brazilian regulatory agency (ANVISA). This new method was compared to a commercial kit (Cobas/Taqman HCV Test v2.0 - Roche), showing virus load results with significant correlation between them (p?=?0,012) using commercial and clinical panels. In addition, 611 samples from patients treated with peguilated alfa-interferon (αPEG-IFN) from different regions of Brazil were analyzed. Our one-step real-time RT-PCR assay demonstrated good performance in viral load measurement and in treatment course monitoring, with acceptable sensitivity and specificity values