983 resultados para Failure Modes
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Seven young men spent three nights and 2 d in a respiration chamber where their rates of energy expenditure and substrate oxidation were continuously measured by indirect calorimetry. During the first 24 h they ingested a mixed maintenance diet containing 35% of calories as fat. An additional amount of 106 +/- 6 g fat/24 h (means +/- SD) was added to this diet during the following 36 h. The fat supplement (987 +/- 55 kcal/d) did not alter 24-h energy expenditure (2783 +/- 232 vs 2820 +/- 284 kcal/d) and failed to promote the use of fat as a metabolic fuel (fat oxidation 1032 +/- 205 vs 1042 +/- 205 kcal/d). The overall energy balance was closely correlated with the fat balance (r = 0.96, p less than 0.001) but not with the carbohydrate balance (r = -0.12, NS). These data indicate that substantial imbalances between intake and oxidation are much more likely for fat than for carbohydrate.
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Why and how do failed states affect neighbouring countries? The attention of the international community towards state failure has grown significantly in recent years, improving the understanding of this phenomenon; nevertheless, the knowledge about the influence of state failure on neighbouring countries remain scarce. This research aims at contributing to filling up the existing gap by analyzing two different cases of state failure –Liberia and Afghanistan– and its consequences on four of their neighbours –Sierra Leone, Guinea, Pakistan and Tajikistan. More concretely, this research investigates the importance of insurgency movements in the relationship between these countries. The research argues that failed states generate conflict-enhancing mechanisms –which might lead to conflict outbreak– in their neighbours through the creation of informal networks. The empiric evidence shows how insurgency-based informal networks have a decisive role in the outbreak of conflict.
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Atrial natriuretic peptides (ANP) exert vasodilating and natriuretic actions. The present study was undertaken to test the effect of low dose infusions of synthetic ANP on hemodynamic and humoral variables of patients with severe heart failure. Eight patients, aged 26 to 71 years, with severe congestive heart failure due to ischemic heart disease or idiopathic dilated cardiomyopathy were included in the study. Synthetic human (3-28) ANP was infused at doses ranging from 0.5 to 2 micrograms/min for up to 3 h. Pulmonary capillary wedge pressure fell from 24 +/- 1 to 16 +/- 2 mm Hg (mean +/- SEM) (p less than 0.01) and cardiac index tended to rise from 2 +/- 0.2 to 2.3 +/- 0.2 L/min/m2 (NS), while blood pressure and heart rate did not change. One patient experienced a marked drop in pulmonary capillary wedge and arterial blood pressure that necessitated the administration of saline. ANP infusion did not alter plasma renin activity or plasma aldosterone, norepinephrine, or vasopressin levels. It decreased plasma epinephrine levels from 0.472 +/- 0.077 to 0.267 +/- 0.024 nmol/L (p less than 0.05). Plasma ANP levels were markedly elevated in all patients before initiating the infusion. They had no predictive value for the hemodynamic response to exogenous ANP. No correlation was observed between the hemodynamic effects of ANP and those induced by the subsequently administered converting enzyme inhibitor captopril, which seemed to improve cardiac function more consistently.(ABSTRACT TRUNCATED AT 250 WORDS)
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Background: The RCP is a 14 French collapsable percutaneous cardiovascular support device positioned in the descending part of the thoracic aorta via the femoral artery. A 10 patient first in man study demonstrated device safety and significant improvement in renal function among high risk PCI patients. We now report haemodynamic and renal efficacy in patients with ADHF.Methods: Prospective non randomised study seeking to recruit 20 patients with ADHF with a need for inotropic or mechanical circulatory support with: i) EF < 30% ii)Cardiac index(CI) < 2.2 L / min / m2 Outcome measures included: 1) Cardiac index (CI) 2) Pulmonary Capillary Wedge Pressure (PCWP) 3) Urine output / serum creatinine 4) Vascular / device complications 5) 30 day mortalityResults: INTERIM ANALYSIS (n=12) The mean age of the study group was 64 years, with a mean baseline creatinine of 193 umol/L, eGFR 38 ml/min. The intended RCP treatment period was 24 hours. During RCP treatment there was a significant mean reduction of PCWP at 4 hours of 17% (25 to 21 mmHg p=0.04). Mean CI increased at 12 hours by 11%, though not reaching significance (1.78 to 1.96 L/min/m2 p=0.08). RCP insertion prompted substantial diuresis. Urine output tripled over the first 12 hours compared to baseline (55 ml/hr vs 213 ml/hr p=0.03). This was associated with significantly improved renal function, a 28% reduction in serum creatinine at 12 hours (193 to 151 umol/L p=0.003), and a increase in eGFR from 38 ml/min to 50 ml/min (p=0.0007). 2 patients previously refused cardiac transplantation were reassessed and successfully transplanted within 9 months of RCP treatment on the basis of demonstrable renal reversibility. There were no vascular or device complications. There were 2 deaths at 30 days, one from multi-organ failure and sepsis, and one from intractable heart failure - neither were device related.Conclusion: RCP support in ADHF patients was associated with improved haemodynamics, and an improvement in renal function. The Reitan Catheter Pump may have a role in providing percutaneous cardiovascular and renal support in the acutely decompensated cardiac patient, and may have a role in suggesting renal reversibility in potential cardiac transplant patients. Further data will be reported at recruitment completion.
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BACKGROUND & AIMS: The study was designed to investigate and quantify nutritional support, and particularly enteral nutrition (EN), in critically ill patients with severe hemodynamic failure. METHODS: Prospective, descriptive study in a surgical intensive care unit (ICU) in a university teaching hospital: patients aged 67+/-13 yrs (mean+/-SD) admitted after cardiac surgery with extracorporeal circulation, staying 5 days in the ICU with acute cardiovascular failure. Severity of disease was assessed with SAPS II, and SOFA scores. Variables were energy delivery and balance, nutrition route, vasopressor doses, and infectious complications. Artificial feeding delivered according to ICU protocol. EN was considered from day 2-3. Energy target was set 25 kcal/kg/day to be reached stepwise over 5 days. RESULTS: Seventy out of 1114 consecutive patients were studied, aged 67+/-17 years, and staying 10+/-7 days in the ICU. Median SAPS II was 43. Nine patients died (13%). All patients had circulatory failure: 18 patients required intra-aortic balloon-pump support (IABP). Norepinephrine was required in 58 patients (83%). Forty patients required artificial nutrition. Energy delivery was very variable. There was no abdominal complication related to EN. As a mean, 1360+/-620 kcal/kg/day could be delivered enterally during the first 2 weeks, corresponding to 70+/-35% of energy target. Enteral nutrient delivery was negatively influenced by increasing dopamine and norepinephrine doses, but not by the use of IABP. CONCLUSION: EN is possible in the majority of patients with severe hemodynamic failure, but usually results in hypocaloric feeding. EN should be considered in patients with careful abdominal and energy monitoring.
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To assess the role of vasopressin (AVP) in congestive heart failure (CHF), we investigated 10 patients with CHF refractory to conventional treatment, before and 60 minutes after intravenous administration of 5 micrograms/kg of d(CH2)5Tyr(Me)AVP, a specific antagonist of AVP at the vascular receptor level. Heart rate, systemic arterial pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure, cardiac index by thermodilution, and cutaneous blood flow by laser-Doppler technique were measured. In 9 patients there was no significant hemodynamic and cutaneous blood flow response to the AVP antagonist. Plasma AVP was 2.3 +/- 0.8 pg/ml and plasma osmolality 284 +/- 14 mosm/kg H2O. The tenth patient had the most severe CHF. His plasma AVP was 55 pg/ml and plasma osmolality 290 mosm/kg. He responded to the AVP antagonist with a marked decrease in systemic arterial pressure from 115/61 to 79/41 mm Hg, in pulmonary arterial pressure from 58/31 to 33/13 mm Hg and in pulmonary capillary wedge pressure from 28 to 15 mm Hg. Simultaneously cardiac index increased from 1.1 to 2.21 X min-1 X m-2 and cutaneous blood flow rose 5-fold. Thus, most patients with CHF have only moderately elevated plasma AVP and its role in determining peripheral vascular resistance appears to be limited. AVP may become important in rare patients presenting with marked hemodynamic instability and very high plasma AVP.
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A 5-year-old previously healthy boy was admitted for abdominal pain and vomiting. Physical examination showed tachypnoe (32/min), hepatomegaly and painful palpation of the upper right abdominal quadrant. Laboratory tests were normal except for elevated ammonium (202mcmol/l). Chest X-ray was performed, showing cardiomegaly and interstitial edema. Transthoracic echocardiography revealed dilated left cavities and LV hypertrophy together with a diffuse hypokinesia and LVEF of 30-40%. Diuretics and ACE-inhibitors were introduced. At that time, the differential diagnosis for the DCM included myocarditis, congenital or genetic, metabolic or autoimmune disease. The next day, the boy underwent cardiac magnetic resonance (CMR) examination, showing a severe dilatation of the LV with an end-diastolic diameter of 50mm and a volume of 150ml. LVEF was 20% with diffuse LV hypokinesia (Fig. 1). No late enhancement was present after Gadolinium injection, ruling out myocarditis. Further laboratory metabolic analysis indicated severely decreased total and free carnitin levels and low renal carnitin reabsorption, corroborating the diagnosis of primary carnitin deficiency (PCD). Carnitin substitution was initiated. The clinical condition rapidly improved. No symptoms of heart failure were present anymore. A follow-up CMR performed 9 months later confirmed the recovery. LV end-diastolic volume decreased from 150ml to 66ml, LVEF increased from 20% to 55% (Fig. 2). Late enhancement was absent after Gadolinum injection (Fig. 3).Carnitin is required for the transport of fatty acids from the cytosol into mitochondria during lipid breakdown. 75% of carnitin is obtained from food, 25% is endogenously synthesized. PCD is an autosomal recessive disorder resulting from impairment of a transporter activity, caused by mutation of the SLC22A5 gene. Incidence is about 1 in 40'000 newborns. Diagnosis is usually made at age 1 to 7. Three forms of PCD are described. In the form associated with cardiomyopathy, the disease is progressive and patient die from heart failure if not treated. Substitution of L-Carnitin leads to a dramatic improvement of disease course.This case underlines the crucial role of etiologic diagnostics in this reversible form of DCM. Early diagnostics and therapy are critical for the prognosis of the patient. This is furthermore an example of a role played by CMR in the diagnostic work-up of heart failure and its follow-up under therapy.
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OBJECTIVES: Increasing evidence suggests that left ventricular remodeling is associated with a shift from fatty acid to glucose metabolism for energy production. The aim of this study was to determine whether left ventricular remodeling with and without late-onset heart failure after myocardial infarction is associated with regional changes in the expression of regulatory proteins of glucose or fatty acid metabolism. METHODS: Myocardial infarction was induced in rats by ligation of the left anterior descending coronary artery (LAD). In infarcted and sham-operated hearts the peri-infarction region (5-mm zone surrounding the region at risk), the interventricular septum and the right ventricular free wall were separated for analysis. RESULTS: At 8 and 20 weeks after LAD ligation, the peri-infarction region and the septum exhibited marked re-expression of atrial natriuretic factor [+252+/-37 and +1093+/-279%, respectively, in the septum (P<0.05)] and of alpha-smooth muscle actin [+34+/-10 and +43+/-14%, respectively, in the septum (P<0.05)]. At 8 weeks, when left ventricular hypertrophy was present without signs of heart failure, myocardial mRNA expression of glucose transporters (GLUT-1 and GLUT-4) was not altered, whereas mRNA expression of medium-chain acyl-CoA dehydrogenase (MCAD) was significantly reduced in the peri-infarction region (-25+/-7%; P<0.05). In hearts exhibiting heart failure 20 weeks after infarct-induction there was a change in all three ventricular regions of both mRNA and protein content of GLUT-1 [+72+/-28 and +121+/-15%, respectively, in the peri-infarction region (P<0.05)] and MCAD [-29+/-9 and -56+/-4%, respectively, in the peri-infarction region (P<0.05)]. CONCLUSION: In rats with large myocardial infarction, progression from compensated remodeling to overt heart failure is associated with upregulation of GLUT-1 and downregulation of MCAD in both the peri-infarction region and the septum.
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OBJECTIVE : To determine the prevalence of patient-ventilator asynchrony in patients receiving non-invasive ventilation (NIV) for acute respiratory failure. DESIGN : Prospective multicenter observation study. SETTING : Intensive care units in three university hospitals. METHODS: Patients consecutively admitted to ICU were included. NIV, performed with an ICU ventilator, was set by the clinician. Airway pressure, flow, and surface diaphragmatic electromyography were recorded continuously for 30 min. Asynchrony events and the asynchrony index (AI) were determined from visual inspection of the recordings and clinical observation. RESULTS: A total of 60 patients were included, 55% of whom were hypercapnic. Auto-triggering was present in 8 (13%) patients, double triggering in 9 (15%), ineffective breaths in 8 (13%), premature cycling 7 (12%) and late cycling in 14 (23%). An AI > 10%, indicating severe asynchrony, was present in 26 patients (43%), whose median (25-75 IQR) AI was 26 (15-54%). A significant correlation was found between the magnitude of leaks and the number of ineffective breaths and severity of delayed cycling. Multivariate analysis indicated that the level of pressure support and the magnitude of leaks were weakly, albeit significantly, associated with an AI > 10%. Patient comfort scale was higher in pts with an AI < 10%. CONCLUSION: Patient-ventilator asynchrony is common in patients receiving NIV for acute respiratory failure. Our results suggest that leaks play a major role in generating patient-ventilator asynchrony and discomfort, and point the way to further research to determine if ventilator functions designed to cope with leaks can reduce asynchrony in the clinical setting.
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AbstractArticle StructureFigures and TablesReferences Benefits from probiotic micro-organisms have been recognised for over 100 years, and as being useful in poultry for 50 years. Fuller (1989) redefined probiotics as ‘a live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance’. Benefits derived from this improved intestinal microbial balance could be reflected in performance or prevention of pathogen colonisation. Probiotic micro-organisms use in poultry production has been widely accepted and new opportunities arose from the 2006 EU ban on antimicrobial growth promoters. The majority of microbial products for compound feeds are made up from a relatively small number of micro-organisms that are normally present in the GI tract. They include non-sporulated bacteria, sporulated bacteria, fungi or yeasts; and presented from single to multi-strain products. A review on the proposed modes of action is presented including recent approaches to quorum sensing interference