Sep 26, · This study aims to investigate the economic aspects and sustainability issues of ethanol production with a systematic literature review. During the selection process, 64 studies from a total of 16, identified articles were analyzed in-depth. There is a consensus that first-generation production methods cannot result in a long-term solution CHAPTER 2 Review of Related Literature and Studies Foreign Literature Student Performance Galiher () and Darling (), used GPA to measure student performance because the main focus in the student performance for the particular semester. Study shows that our emotional system is a complex, widely distributed, and error-prone system Sep 18, · Rapidly growing the power consumption and decrease in generating and transmission capacities have set the trend towards the Distributed Generation (DG) sources. Still there is not a univer sal definition of DG. This paper discusses the different definitions proposed in the literature
An Overview of Chronic Disease Models: A Systematic Literature Review
Try out PMC Labs and tell us what you think. Learn More. e Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA. The aim of the review was to summarize the literature over the last 25 years regarding bicarbonate administration in out-of-hospital cardiac arrest. Clinical and experimental data raised questions regarding the safety and effectiveness of sodium bicarbonate SB administration during cardiac arrest.
Earlier advanced cardiac life support ACLS guidelines recommended routine bicarbonate administration as part of the ACLS algorithm, but recent guidelines no longer recommend its use.
The debate in the literature is ongoing, but at the present time, SB administration is only recommended for cardiac arrest related to hypokalemia or overdose of tricyclic antidepressants. Several studies challenge the assumption distributed generation literature review bicarbonate administration is beneficial for treatment of acidosis in cardiac arrest. At the present time, there is a trend against using bicarbonates in cardiac arrest, and this trend is supported by guidelines published by professional societies and organizations.
Sodium bicarbonate SB administration has been considered an important part of treatment for severe metabolic acidosis in cardiac arrest, because, based on pathophysiologic considerations, normalization of extracellular and intracellular pH was distributed generation literature review a meaningful endpoint of resuscitation.
Correction of metabolic acidosis with SB was recommended by early advanced cardiac life support ACLS guidelines published in [ 1 ], and SB was the medication most frequently used during cardiac arrest until the mids [ 2 ]. However, because of concerns regarding potential benefit vs. harm, distributed generation literature review, SB use fell progressively to almost no use byaccording to one study from the UK [ 3 ]. At the present time, SB administration in cardiac arrest is controversial and matter of ongoing debate, and frequency of use varies greatly between medical centers [ 4 ].
The aim of this review was to summarize the literature of the last 25 years regarding the potential benefit or harm of SB administration for treatment of acidosis in patients with cardiac arrest. The search was conducted in Marchbut was updated in Novemberin order to include the latest update of the AHA guidelines for cardiopulmonary resuscitation. The search was limited to articles and reviews written in English, or articles written in other languages but accompanied by a detailed meaningful abstract in English, that were published in the last 25 years.
The bibliography from all extracted manuscripts was further reviewed for identification of additional relevant references which were included in this review. A distributed generation literature review study published by Roberts et al in attempted to identify predictors of mortality in patients resuscitated from cardiac arrest, and showed that survival was only 4. However, the authors pointed out that poor survival in patients who received SB could reflect more severe illness with presence distributed generation literature review severe distributed generation literature review acidosis among patients who required SB [ 9 ].
An observational cohort study published by Stiell et al in evaluated patients who suffered cardiac arrest inside or outside the hospital and received epinephrine according to ACLS protocol guidelines. The study was conducted over a 2-year period and used univariate and multivariate logistic regression to assess the association between six ACLS drugs and survival at 1 h and at hospital discharge.
With the exception of procainamide, all standard ACLS drugs, including SB, did not have significant association with survival. However, the authors noted that timing of drug administration could be an important factor [ 10 ]. A prospective, randomized, double-blind trial published by Dybvik et al in enrolled adults who were resuscitated after out-of-hospital cardiac arrest due to asystole or ventricular fibrillation and failed the first defibrillation attempt.
The study compared outcomes in patients who received mL of SB-trometamol-phosphate mixture vs. The benefit of medications recommended by ACLS support guidelines was questioned by a prospective cohort study on patients resuscitated after cardiac arrest published by van Walraven et al in This study showed that only of patients survived the first hour.
Despite the observed association between bicarbonate use and unsuccessful outcome, the authors concluded that their study did not find association between ACLS medications, including bicarbonate and successful resuscitation [ 12 ]. A review article published by Adgey and Johnston in assessed earlier publications and concluded that use of buffer solutions should be limited to cardiac arrests where there is documented severe acidosis, and should be given blindly only after prolonged resuscitation, or in cardiac arrest associated with hyperkalemia or tricyclic antidepressant overdose [ 13 ].
Similarly, a review published by Datta et al in assessed basic life support, advanced life support and post-resuscitation care, and concluded that routine use of bicarbonates was not recommended in cardiac arrest [ 14 ], distributed generation literature review.
A large retrospective study published by Bar-Joseph et al in based on the brain resuscitation clinical trial III, reviewed records from 2, patients and found a linear relationship between duration of ACLS and bicarbonate use. The brain resuscitation clinical trial III was a multicenter randomized trial comparing standard vs. high-dose epinephrine during cardiopulmonary resuscitation CPRwhile SB use was optional, distributed generation literature review.
The authors concluded that, when bicarbonate was used, it was probably used late, and suggested that, because of development of severe metabolic acidosis, bicarbonate administration should start early [ 15 ].
However, these findings were contradicted by a second retrospective study published by Bar-Joseph et al inwhich was also based on the brain resuscitation clinical trial III database, except it only included patients with out-of-hospital cardiac arrest where the time from collapse to initiation of ACLS was shorter than 30 min, and included data from 2, patients.
Multivariate regression analysis in this dataset showed that earlier and more frequent use of SB was related to improved chance of return of spontaneous circulation ROSC and better long-term outcome [ 4 ].
Vukmir and Katz published in the results of a prospective randomized, double-blinded pre-hospital clinical trial that was conducted in Pennsylvania between andbefore early defibrillation by first distributed generation literature review was introduced to clinical practice.
Of registered potentially eligible patients with pre-hospital cardiopulmonary arrest, patients were enrolled in the study. The primary outcome was ROSC or arrival to the emergency department with a pulse. Overall, there was no difference in survival, as 58 of patients However, in the subgroup of patients with prolonged longer than 15 min pre-hospital cardiac arrest, survival was A review article published by Spohr et al in concluded that only a few drugs conferred a proven benefit for short-term survival after cardiac arrest, and suggested that bicarbonates should only be administered during CPR if indicated based on arterial blood gas analysis or in cases of prolonged unsuccessful resuscitation [ 17 ].
The authors suggested that early ABG analysis in cardiac arrest may help optimize pH and reduce the frequency of empiric, not warranted, bicarbonate use [ 18 ].
A review from Lee in mentioned the role of drugs administration after effective CPR and defibrillation in the cardiac arrest, but based on randomized trials, no drugs or combination of them have shown benefit on long-term survival [ 19 ].
A review by Williamson et al in reported that although short-term outcomes after CPR have improved as result of the administration of code drugs, in most cases there was no significant benefit with regard to the final outcome [ 20 ]. A retrospective cohort study published by Weng et al in included data from 92 patients who presented to the emergency department with cardiac arrest.
The authors compared 30 patients who received vs. Although patients who received bicarbonate had higher percentage of ROSC, regression analysis showed that bicarbonate administration did not significantly improve the rate of ROSC in out-of-hospital cardiac arrest [ 21 ], distributed generation literature review.
The findings of all the above clinical studies are summarized in Table 1 [ 4distributed generation literature review,151618 distributed generation literature review, ]. ABG: arterial blood gas; ACLS: advanced cardiac life support; CI: confidence interval; CPR: cardiopulmonary resuscitation; min: minutes; epi: epinephrine; pts: patients; OR: odds ratio; RCT: randomized controlled trial; ROSC: return of spontaneous circulation; SB: sodium bicarbonate.
Debate regarding the potential benefit vs. harm from administration of SB in CPR has been ongoing for decades. Bicarbonate administration was recommended by early ACLS guidelines published in [ 1 ], and this recommendation continued when these guidelines were updated in [ 29 ], but concern about potential harm made bicarbonate use in cardiac arrest increasingly controversial in recent years.
As significant acidosis is related to serious adverse systemic effects, bicarbonate administration seems a reasonable intervention to counteract the severe metabolic acidosis caused by hypoxia, poor perfusion and increased lactate production in cardiac arrest, in an attempt to mitigate the adverse effects of acidosis, improve response to exogenously administered catecholamines and increase venous return, thereby improving coronary perfusion pressure [ 30 ].
Failure of ventilation and perfusion in cardiac arrest causes severe disruption of homeostasis, distributed generation literature review. In addition, respiratory failure with compromised ventilation reduces CO 2 elimination, resulting in CO 2 accumulation and respiratory acidosis. Severe combined metabolic and respiratory acidosis and impaired oxygen tissue delivery result in cell damage, as evidenced by cardiac dysfunction from decreased myocardial contractility, hypotension, and renal, hepatic and central nervous system injury that can progress to multi-organ failure.
Because of concerns regarding the deleterious effects of acidosis, clinicians have used bicarbonates as buffer to offset the high acid production, in an attempt distributed generation literature review help the body restore normal homeostasis in cardiac arrest.
Data published in the s raised concerns that SB administration during cardiac arrest can worsen the distributed generation literature review after cardiac arrest and emphasized the adverse effects of bicarbonates, distributed generation literature review, including increased osmolality [ 22 ].
However, distributed generation literature review, newer data from experiments in pigs showed that hypertonic buffer solutions in the absence of vasopressors can reduce coronary perfusion pressure below critical thresholds during cardiac arrest and CPR, and may adversely affect outcome [ 35 ]. In contrast, an experimental study published by Liu et al in showed that administration of bicarbonate buffer solution promoted cerebral reperfusion and mitigated cerebral acidosis after restoration of spontaneous circulation in piglets [ 36 ].
Similarly, data from experiments with CPR in rats suggested that administration of SB or other buffer solutions can improve survival by ameliorating post-arrest myocardial dysfunction [ 37 ].
However, despite encouraging experimental data, concerns about possible detrimental effects of SB administration in cardiac arrest distributed generation literature review. Few human studies have examined the benefits of bicarbonate administration in cardiac arrest, distributed generation literature review, and most of them are dated beforeat a time when SB administration was routine during CPR, even though the acid-base status of patients was not known in the majority of cases.
However, that practice has changed over the years due to concerns about adverse effects of bicarbonate administration and the fact that published clinical studies failed to show specific benefits from their use [ 112425distributed generation literature review, 38 ]. Published data in recent years suggest that SB administration can have deleterious effects during cardiac arrest, including increased intracellular acidosis, reduced cardiac output, shift of the oxygen dissociation curve to the left, with increased affinity of hemoglobin for oxygen resulting in reduced oxygen tissue release, hypernatremia and hyperosmolarity [ 39 ].
As increased blood and tissue CO 2 concentration leads to worsening of tissue acidosis in major organs, including the heart, possibly contributing to cardiac dysfunction, it may be detrimental to cardiac resuscitation [ 26]. In response to concerns raised by these studies, routine use of SB in cardiac arrest has been discouraged, and the AHA has deemphasized its use in the ACLS algorithms [ 5 ]. The main goal in cardiac arrest treatment is distributed generation literature review intervene as early as possible, with emphasis on early activation of the emergency response system, early initiation of CPR and early defibrillation, in an attempt to improve outcome.
Drug administration still has a role in attempts to improve organ perfusion during CPR, facilitate electrical defibrillation, reduce myocardial irritability, terminate malignant ventricular arrhythmias, minimize metabolic derangements and protect the brain from the effects of ischemia [ 44 ]. Buffering solutions other than SB have also been used to correct the metabolic acidosis during cardiac arrest.
A review published in by Bjerneroth reported that different alkaline buffers have been used, but have not shown any benefit because of numerous deleterious effects [ 45 ]. Tribonat, a mixture of THAM, acetate, SB and phosphate, distributed generation literature review, has been proposed as suitable alternative to conventional buffer solutions. A review published by Bjerneroth in assessed 76 publications and, although it did not find improvement in overall survival, it suggested that Tribonat may be superior compared to previously used buffer solutions in cases where administration of an alkalinizing agent is indicated [ 46 ].
Some studies have suggested a beneficial role for bicarbonate in the treatment of distributed generation literature review acidosis associated with cardiac arrest of prolonged duration, while other studies showed that bicarbonate administration may be counter-productive because it increases tissue and central venous blood carbon dioxide tension.
Decisions regarding bicarbonate administration should therefore be based on distributed generation literature review venous blood gas analysis [ 47 ]. Historically, a report by Stewart in described 12 cases of cardiac arrest and, although it showed that correction of metabolic acidosis increased the chances of successful treatment, it also suggested that bicarbonate administration is not warranted in all cardiac arrest cases [ 48 ].
A retrospective study published by Aufderheide et al in reviewed data from 3 years of clinical experience with use of SB in patients successfully resuscitated from cardiac arrest, and assessed the potential harms from bicarbonate use.
Also a review by Vukmir et al published in analyzed all studies before that time showing that six of nine studies reported some prolongation of survival time after cardiac arrest, with one study reporting worse outcome and two studies showing no effect of bicarbonate on survival, but most of these studies were uncontrolled [ 30 ].
Although SB use has been part of standard therapy for treatment of acidosis in cardiac arrest, data published over the last 25 years do not support its use. The AHA revised the ACLS guidelines since the edition distributed generation literature review standards and guidelines for CPR and emergency cardiac care ECCso that SB administration is only advised at the discretion of the physician directing the resuscitation.
A mL bolus of SB will raise serum pH approximately 0. The revised AHA guidelines for CPR and ECC emphasize that acidosis and acidemia are dynamic processes resulting from the absence of blood flow in cardiac arrest [ 5 ], therefore high quality CPR and early defibrillation in attempt to restore spontaneous circulation are the best methods to restore acid-base balance, with additional benefit gained by ventilation. The majority of studies cited in these guidelines showed poor outcomes and no benefit distributed generation literature review bicarbonate administration, while only two studies distributed generation literature review increased ROSC and survival to hospital discharge.
In addition, the AHA ACLS guidelines mentioned significant potential adverse effects related to bicarbonate administration during cardiac arrest, including inactivation of simultaneously administered catecholamines, reduction of systemic vascular resistance, hypernatremia, hyperosmolality and extracellular alkalosis despite intracellular PCO 2 excess [ 7 ].
Because of the above reservations, current ACLS guidelines recommend bicarbonate administration only in cases of cardiac arrest related to hyperkalemia or tricyclic antidepressant overdose [ 7 ], distributed generation literature review. Alternative, non-CO 2 generating buffers, such as THAM and Tribonate, have potential for minimizing the adverse effects of SB, but clinical experience and outcome data are very limited.
Last, according to the ACLS guidelines published by the AHA, routine SB administration is not recommended in the ACLS protocol for pulseless electrical activity, distributed generation literature review this is a class III recommendation, based on LOE B limited populations evaluated, data derived from a single randomized trial or non-randomized studies [ 5 ].
Additional research is needed to elucidate further the effects of SB on organ function, on the likelihood of ROSC and on survival in patients resuscitated from cardiac arrest. This work was supported solely by department funds. All authors state that they do not have any conflicts of interest to report.
DV did literature search and wrote the manuscript; VK assisted with literature search and edited manuscript; CP collected data and edited manuscript; IK reviewed the literature and edited manuscript; CA did literature search and edited manuscript; MK reviewed the literature, edited and finalized the manuscript.
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Distributed Generation and Net Metering (3 minutes)
, time: 2:55A Review on Distributed Generation Definitions and DG Impacts on Distribution System | BibSonomy
Sep 18, · Rapidly growing the power consumption and decrease in generating and transmission capacities have set the trend towards the Distributed Generation (DG) sources. Still there is not a univer sal definition of DG. This paper discusses the different definitions proposed in the literature Jun 11, · Nanomaterials have been widely used in many fields in the last decades, including electronics, biomedicine, cosmetics, food processing, buildings, and aeronautics. The application of these nanomaterials in the medical field could improve diagnosis, treatment, and prevention techniques. Graphene oxide (GO), an oxidized derivative of graphene, is currently used in Aug 12, · Fig. 2 is exemplifying the various associated blockchain capabilities for booming industry implementation perspectives. There is a broad education domain, healthcare services, extensive support in logistics and transportation, and government agencies. The overall blockchain conceptualisation focused on enhancing these spheres from basics to achieve all
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