Comparison of esCCO and transthoracic echocardiography for non-invasive measurement of cardiac output intensive care.

BACKGROUND: The esCCO monitor (ECG- estimated Continuous Cardiac Output, Nihon Kohden(®)) is a new non-invasive tool for estimating cardiac output (CO). It derives CO from the pulse wave transit time (PWTT) estimated by the ECG and the plethysmographic wave. An initial calibration is needed to refine the relation linking pulse pressure (measured by arterial pressure cuff) to PWTT. To assess the accuracy and reliability of the esCCO system, we performed an analysis of agreement of CO values obtained by transthoracic echocardiography (TTE). METHODS: Thirty-eight intensive care unit patients were prospectively included. CO was determined simultaneously using esCCO (CO(esCCO)) and TTE (CO(TTE)) as our reference method. RESULTS: A total of 103 paired readings from 38 patients were collected. The correlation coefficient between CO(esCCO) and CO(TTE) was 0.61 (P<0.001). The Bland and Altman analysis corrected for repeated measures showed a bias of -1.6 litre min(-1) and limits of agreement from -4.7 to +1.5 litre min(-1), with a percentage error (2 sd/mean CO) of 49%. The correlation for CO changes was significant (R=0.63, P<0.001), but the concordance rate was poor (73%). Polar plot analysis showed an angular bias of -9° with radial limits of agreement from -54° to +36°. The bias appeared to correlate with systemic vascular resistance (R=-0.45, P<0.001). CONCLUSIONS: In critically ill patients, the performance of the esCCO monitor was not clinically acceptable, and this monitor cannot be recommended in this setting. Moreover, the esCCO failed to trend CO data reliably.

Trough/peak ratios of once daily angiotensin converting enzyme inhibitors and calcium antagonists.

Medications given once daily may increase compliance for treatment of hypertension, if the drugs have a prolonged duration of action. The time-effect profiles for antihypertensive drugs may not depend entirely on pharmacokinetic measurements (plasma levels). Thus, trough/peak effects on blood pressure should be measured. It has been suggested that trough/peak ratios be greater than 50% for optimal 24-h control of pressure. Because very little information is available for many angiotensin converting enzyme (ACE) inhibitors and calcium antagonists concerning their trough/peak ratios and awaiting prospective comparative trials with adequate methodology, we have analyzed the duration of action of blood pressure lowering during long-term therapy with commercially available ACE inhibitors and calcium antagonists in published studies that used ambulatory blood pressure monitoring. Published studies were searched in scientific databases using relevant key words. Twenty-four ACE inhibitor and 34 calcium antagonist studies with comparable methodologies were selected. The mean trough/ peak ratios were computed after reconstruction of the curve of the magnitude of blood pressure changes against time. The results showed that once daily administration of ACE inhibitors produced on average ratios higher than 50% with fosinopril (64%), ramipril (50% to 63%), and trandolapril (50% to 100%). Other studied ACE inhibitors produced ratios on average equal to [enalapril (40% to 64%), cilazapril (10% to 80%), lisinopril (30% to 70%)] or significantly lower than 50% [captopril (25%), benazepril (40%), perindopril (35%), quinapril (10% to 40%), and moexipril (0% to 9%)]. As for once daily calcium antagonists, amlodipine (50% to 100%), lacidipine (40% to 100%), nifedipine Coat-Core (50% to 69%), nifedipine gastrointestinal therapeutic system (GITS) (60% to 94%), as well as various "slow release" formulations of diltiazem (20% to 80%) and verapamil (45% to 100%) had on average ratios higher than 50% whereas felodipine ER (30% to 45%), various slow release formulations of isradipine (10% to 80%), and nitrendipine (10% to 80%) had ratios lower than 50%. Although this retrospective literature analysis may have some theoretical limitations, it suggests that not all once daily ACE inhibitors and calcium antagonists cause trough/peak ratio superior to 50%. This may have important clinical implications.

Characterizing mesh size distributions (MSDs) in thermosetting materials using a high-pressure system.

The thermoporosimetry method was adapted to determine the mesh size distribution of an acrylate thermoset clearcoat. This goal was achieved by increasing the solvent rate transfer by increasing the pressure and temperature. A comparison of the results obtained using this approach with those obtained by DMA (dynamic mechanical analysis) underlined the accuracy of thermoporosimetry in characterizing the macromolecular architecture of thermosets. The thermoporosimetry method was also used to analyze the effects of photoaging on cross-linking, which result from the photodegradation of the acrylate thermoset. It was found that the formation of a three-dimensional network followed by densification generates a modification of the average mesh size that leads to a dramatic decrease of the meshes of the polymer.

Genetic identification of the main opportunistic Mucorales by PCR-restriction fragment length polymorphism.

Mucormycosis is a rare and opportunistic infection caused by fungi belonging to the order Mucorales. Recent reports have demonstrated an increasing incidence of mucormycosis, which is frequently lethal, especially in patients suffering from severe underlying conditions such as immunodeficiency. In addition, even though conventional mycology and histopathology assays allow for the identification of Mucorales, they often fail in offering a species-specific diagnosis. Due to the lack of other laboratory tests, a precise identification of these molds is thus notoriously difficult. In this study we aimed to develop a molecular biology tool to identify the main Mucorales involved in human pathology. A PCR strategy selectively amplifies genomic DNA from molds belonging to the genera Absidia, Mucor, Rhizopus, and Rhizomucor, excluding human DNA and DNA from other filamentous fungi and yeasts. A subsequent digestion step identified the Mucorales at genus and species level. This technique was validated using both fungal cultures and retrospective analyses of clinical samples. By enabling a rapid and precise identification of Mucorales strains in infected patients, this PCR-restriction fragment length polymorphism-based method should help clinicians to decide on the appropriate treatment, consequently decreasing the mortality of mucormycosis.