350 research outputs found
Baseline cerebral oximetry values in cardiac and vascular surgery patients: a prospective observational study
<p>Abstract</p> <p>Aim</p> <p>This study was conducted to evaluate baseline INVOS values and identify factors influencing preoperative baseline INVOS values in carotid endarterectomy and cardiac surgery patients.</p> <p>Methods</p> <p>This is a prospective observational study on 157 patients (100 cardiac surgery patients, 57 carotid endarterectomy patients). Data were collected on factors potentially related to baseline INVOS values. Data were analyzed with student's t-test, Chi-square, Pearson's correlation or Linear Regression as appropriate.</p> <p>Results</p> <p>100 cardiac surgery patients and 57 carotid surgery patients enrolled. Compared to cardiac surgery, carotid endarterectomy patients were older (71.05 ± 8.69 vs. 65.72 ± 11.04, P < 0.001), with higher baseline INVOS (P < 0.007) and greater stroke frequency (P < 0.002). Diabetes and high cholesterol were more common in cardiac surgery patients. Right side INVOS values were strongly correlated with left-side values in carotid (r = 0.772, P < 0.0001) and cardiac surgery patients (r = 0.697, P < 0.0001). Diabetes and high cholesterol were associated with significantly (P < 0.001) lower INVOS and smoking was associated with higher INVOS values in carotid, but not in cardiac surgery patients. Age, sex, CVA history, Hypertension, CAD, Asthma, carotid stenosis side and surgery side were not related to INVOS. Multivariate analysis showed that diabetes is strongly associated with lower baseline INVOS values bilaterally (P < 0.001) and explained 36.4% of observed baseline INVOS variability in carotid (but not cardiac) surgery.</p> <p>Conclusion</p> <p>Compared to cardiac surgery, carotid endarterectomy patients are older, with higher baseline INVOS values and greater stroke frequency. Diabetes and high cholesterol are associated with lower baseline INVOS values in carotid surgery. Right and left side INVOS values are strongly correlated in both patient groups.</p
A randomized comparative study of patients undergoing myocardial revascularization with or without cardiopulmonary bypass surgery: The MASS III Trial
The MASS III Trial is a large project from a single institution, The Heart Institute of the University of Sao Paulo, Brazil (InCor), enrolling patients with coronary artery disease and preserved ventricular function. The aim of the MASS III Trial is to compare medical effectiveness, cerebral injury, quality of life, and the cost-effectiveness of coronary surgery with and without of cardiopulmonary bypass in patients with multivessel coronary disease referred for both strategies. The primary endpoint should be a composite of cardiovascular mortality, cerebrovascular accident, nonfatal myocardial infarction, and refractory angina requiring revascularization. The secondary end points in this trial include noncardiac mortality, presence and severity of angina, quality of life based on the SF-36 Questionnaire, and cost-effectiveness at discharge and at 5-year follow-up. In this scenario, we will analyze the cost of the initial procedure, hospital length of stay, resource utilization, repeat hospitalization, and repeat revascularization events during the follow-up. Exercise capacity will be assessed at 6-months, 12-months, and the end of follow-up. A neurocognitive evaluation will be assessed in a subset of subjects using the Brain Resource Center computerized neurocognitive battery. Furthermore, magnetic resonance imaging will be made to detect any cerebral injury before and after procedures in patients who undergo coronary artery surgery with and without cardiopulmonary bypass
North American Prairie Wetlands are Important Nonforested Land-Based Carbon Storage Sites
We evaluated the potential of prairie wetlands in North America as carbon sinks. Agricultural conversion has resulted in the average loss of 10.1 Mg ha- of soil organic carbon on over 16 million ha of wetlands in this region. Wetland restoration has potential to sequester 378 Tg of organic carbon over a 10-year period. Wetlands can sequester over twice the organic carbon as no-till cropland on only about 17% of the total land area in the region. We estimate that wetland restoration has potential to offset 2.4% of the annual fossil CO2 emission reported for North America in 1990
Dexmedetomidine decreases the inflammatory response to myocardial surgery under mini-cardiopulmonary bypass
Tranexamic acid for the prevention of postpartum bleeding in women with anaemia: study protocol for an international, randomised, double-blind, placebo-controlled trial.
BACKGROUND: Postpartum haemorrhage (PPH) is responsible for about 100,000 maternal deaths every year, most of which occur in low- and middle-income countries. Tranexamic acid (TXA) reduces bleeding by inhibiting the enzymatic breakdown of fibrin blood clots. TXA decreases blood loss in surgery and reduces death due to bleeding after trauma. When given within 3 h of birth, TXA reduces deaths due to bleeding in women with PPH. However, for many women, treatment of PPH is too late to prevent death. Over one third of pregnant women in the world are anaemic and many are severely anaemic. These women have an increased risk of PPH and suffer more severe outcomes if PPH occurs. There is an urgent need to identify a safe and effective way to reduce postpartum bleeding in anaemic women. METHODS/DESIGN: The WOMAN-2 trial is an international, multicentre, randomised, double-blind, placebo-controlled trial to quantify the effects of TXA on postpartum bleeding in women with moderate or severe anaemia. Ten thousand women with moderate or severe anaemia who have given birth vaginally will be randomised to receive 1 g of TXA or matching placebo by intravenous injection immediately (within 15 min) after the umbilical cord is cut or clamped. The primary outcome is the proportion of women with a clinical diagnosis of primary PPH. The cause of PPH will be described. Data on maternal health and wellbeing, maternal blood loss and its consequences, and other health outcomes will be collected as secondary outcomes. The main analyses will be on an 'intention-to-treat' basis, irrespective of whether the allocated treatment was received. Results will be presented as appropriate effect estimates with a measure of precision (95% confidence intervals). Subgroup analyses will be based on the severity of anaemia (moderate versus severe) and type of labour (induced or augmented versus spontaneous). A study with 10,000 patients will have over 90% power to detect a 25% relative reduction from 10 to 7.5% in PPH. The trial will be conducted in hospitals in Africa and Asia. DISCUSSION: The WOMAN-2 trial should provide reliable evidence for the effects of TXA for preventing postpartum bleeding in women with anaemia. TRIAL REGISTRATION: ISRCTN, ISRCTN62396133 . Registered on 7 December 2017; ClincalTrials.gov, ID: NCT03475342 . Registered on 23 March 2018
Plasmodium falciparum Parasites Are Killed by a Transition State Analogue of Purine Nucleoside Phosphorylase in a Primate Animal Model
Plasmodium falciparum causes most of the one million annual deaths from malaria. Drug resistance is widespread and novel agents against new targets are needed to support combination-therapy approaches promoted by the World Health Organization. Plasmodium species are purine auxotrophs. Blocking purine nucleoside phosphorylase (PNP) kills cultured parasites by purine starvation. DADMe-Immucillin-G (BCX4945) is a transition state analogue of human and Plasmodium PNPs, binding with picomolar affinity. Here, we test BCX4945 in Aotus primates, an animal model for Plasmodium falciparum infections. Oral administration of BCX4945 for seven days results in parasite clearance and recrudescence in otherwise lethal infections of P. falciparum in Aotus monkeys. The molecular action of BCX4945 is demonstrated in crystal structures of human and P. falciparum PNPs. Metabolite analysis demonstrates that PNP blockade inhibits purine salvage and polyamine synthesis in the parasites. The efficacy, oral availability, chemical stability, unique mechanism of action and low toxicity of BCX4945 demonstrate potential for combination therapies with this novel antimalarial agent
Retrospective evaluation of the effect of carotid artery stenosis on cerebral oxygen saturation during off-pump coronary artery bypasses grafting in adult patients
Influence of the postoperative inflammatory response on cognitive decline in elderly patients undergoing on-pump cardiac surgery: a controlled, prospective observational study
BACKGROUND: The role of non-infective inflammatory response (IR) in the aetiology of postoperative cognitive dysfunction (POCD) is still controversial. The aim of this controlled, prospective observational study was to assess the possible relationship between the grade of IR, defined by procalcitonin (PCT) changes, and development of POCD related to cardiac surgery. METHODS: Forty-two patients, who were >/= 60 years of age and scheduled for elective cardiac surgery, were separated into the low inflammatory (LIR) and high inflammatory (HIR) response groups based on their PCT levels measured on the first postoperative day. A matched normative control group of 32 subjects was recruited from primary care practice. The PCT and C-reactive protein (CRP) levels were monitored daily during the first five postoperative days. The cognitive function and mood state were preoperatively tested with a set of five neurocognitive tests and two mood inventories and at the seventh postoperative day. The Reliable Change Index modified for practice (RCIp) using data from normative controls was applied to determine the significant decline in test performance. RESULTS: The LIR (n = 20) and HIR (n = 22) groups differed significantly in the PCT (p 0.05). Additionally, there was no difference in the mood states, anxiety levels and perioperative parameters known to influence the development of POCD. CONCLUSIONS: In this study, the magnitude of the non-infective inflammatory response generated by on-pump cardiac surgery did not influence the development of POCD in the early postoperative period in elderly patients
Consequences of the size structure of fish populations for their effects on a generalist avian predator
Size-structured interspecific interactions can shift between predation and competition, depending on ontogenetic changes in size relationships. I examined the effects of common carp (Cyprinus carpio), an omnivorous fish, on the reproductive success of the red-necked grebe (Podiceps grisegena), an avian gape-limited predator, along a fish size gradient created by stocking distinct age-cohorts in seminatural ponds. Young-of-the-year (0+) carp were an essential food source for young grebes. Only adult birds were able to consume 1-year-old (1+) fish, while 2-year-old (2+) fish attained a size refuge from grebes. Amphibian larvae were the principal alternative prey to fish, followed by macroinvertebrates, but the abundance of both dramatically decreased along the carp size gradient. Fledging success was 2.8 times greater in ponds with 0+ versus 1+ carp; in ponds with 1+ carp, chicks received on average 2.6–3 times less prey biomass from their parents, and over 1/3 of broods suffered total failure. Breeding birds avoided settling on 2+ ponds. These results show that changes in prey fish size structure can account for shifts from positive trophic effects on the avian predator to a negative impact on the predator’s alternative resources. However, competition did not fully explain the decrease in grebe food resources in the presence of large fish, as carp and grebes overlapped little in diet. In experimental cages, 1+ carp totally eliminated young larvae of amphibians palatable to fish. In field conditions, breeding adults of palatable taxa avoided ponds with 1+ and older carp. Non-trophic interactions such as habitat selection by amphibians or macroinvertebrates to avoid large fish may provide an indirect mechanism strengthening the adverse bottom-up effects of fish on birds
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Photoplethysmography for blood volumes and oxygenation changes during intermittent vascular occlusions
Photoplethysmography (PPG) is an optical technique that measures blood volume variations. The main application of dual-wavelength PPG is pulse oximetry, in which the arterial oxygen saturation (SpO[Formula: see text]) is calculated noninvasively. However, the PPG waveform contains other significant physiological information that can be used in conjunction to SpO[Formula: see text] for the assessment of oxygenation and blood volumes changes. This paper investigates the use of near infrared spectroscopy (NIRS) processing techniques for extracting relative concentration changes of oxygenated ([Formula: see text]HbO[Formula: see text]), reduced ([Formula: see text]HHb) and total haemoglobin ([Formula: see text]tHb) from dual-wavelength PPG signals during intermittent pressure-increasing vascular occlusions. A reflectance PPG sensor was attached on the left forearm of nineteen (n = 19) volunteers, along with a reference NIRS sensor positioned on the same forearm, above the left brachioradialis. The investigation protocol consisted of seven intermittent and pressure-increasing vascular occlusions. Relative changes in haemoglobin concentrations were obtained by applying the modified Beer-Lambert law to PPG signals, while oxygenation changes were estimated by the difference between red and infrared attenuations of DC PPGs (A[Formula: see text] = [Formula: see text]A[Formula: see text] - [Formula: see text]A[Formula: see text]) and by the conventional SpO[Formula: see text]. The [Formula: see text]HbO[Formula: see text], [Formula: see text]HHb, [Formula: see text]tHb from the PPG signals indicated significant changes in perfusion induced by either partial and complete occlusions (p < 0.05). The trends in the variables extracted from PPG showed good correlation with the same parameters measured by the reference NIRS monitor. Bland and Altman analysis of agreement between PPG and NIRS showed underestimation of the magnitude of changes by the PPG. A[Formula: see text] indicated significant changes for occlusion pressures exceeding 20 mmHg (p < 0.05) and correlation with tissue oxygenation changes measured by NIRS, while SpO[Formula: see text] had significant changes after 40 mmHg (p < 0.05). Relative changes in haemoglobin concentrations can be estimated from PPG signals and they showed a good level of accuracy in the detection of perfusion and oxygenation changes induced by different degrees of intermittent vascular occlusions. These results can open up to new applications of the PPG waveform in the detection of blood volumes and oxygenation changes
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