Deborah J. Cook

Bio: Deborah J. Cook is an academic researcher from McMaster University. The author has contributed to research in topics: Intensive care & Intensive care unit. The author has an hindex of 173, co-authored 907 publications receiving 148928 citations. Previous affiliations of Deborah J. Cook include McMaster University Medical Centre & Queen's University.

Re-evaluating the Inhibition of Stress Erosions (REVISE): a protocol for pilot randomized controlled trial.

Abstract: INTRODUCTION: Clinicians routinely administer stress ulcer prophylaxis to mechanically ventilated patients in the intensive care unit (ICU), most commonly prescribing proton pump inhibitors (PPIs)....

Systematic review: Intra-aortic balloon counterpulsation pump therapy: a critical appraisal of the evidence for patients with acute myocardial infarction

Abstract: Intra-aortic balloon counterpulsation pump (IABP) therapy has been used in several clinical situations, predominantly in critically ill patients, since 1968 [1]. In acute myocardial infarction (AMI) patients who are experiencing continued ischemia, IABP therapy may be used in an attempt to improve patency of an infarct-related coronary artery (IRA) and reduce the rates of recurrent myocardial ischemia and its sequelae. The mechanism for this benefit is thought to be a combination of reduced oxygen demand [2], increased coronary artery blood flow velocity [3], and augmentation of diastolic arterial pressure enhancing thrombolysis, leading to faster reperfusion [4]. IABP therapy may also be used in patients with ventricular septal rupture, severe mitral regurgitation, and cardiogenic shock. The technique for IABP therapy involves insertion of an 8 or 9.5 Fr helium-filled balloon via the femoral artery into the descending aorta. The device is preferably inserted through an existing vascular access site in an attempt to reduce the rate of vascular and hemorrhagic complications. It is crucial that the tip be positioned distal to the left subclavian artery, but proximal to the renal arteries. The balloon is synchronized to deflate during early systole, thus decreasing left ventricular (LV) afterload. In turn, LV ejection fraction (EF) and stroke volume (SV) are enhanced, leading to reduced myocardial oxygen consumption. The balloon inflates during early diastole, thus increasing coronary blood flow and peripheral perfusion. The IABP is usually commenced at a rate of 1 : 1. Once the benefit of IABP therapy is thought to be concluded, patients are usually gradually weaned from the pump at rates of 1 : 2 to 1 : 3 over 6-12 h. Following the procedure, one must ensure that the patient has adequate radial artery pulses, suggesting no IABP interference with the subclavian arteries. A chest roentgenogram should be inspected for the location of the IABP marker, which should be 1-2 cm below the aortic arch knuckle. The patient's serum creatinine and urine output should be followed for evidence of IABP interference with the renal arteries. When used to prevent recurrent ischemia post-AMI, all patients who receive IABP therapy should also be prescribed daily aspirin and systemic heparinization with 1000-2000 U/h infused for at least 48 h to maintain activated partial thromboplastin time (aPTT) between 50 and 84 s. Contraindications to IABP use include severe peripheral vascular disease (PVD), defined as diminished femoral pulses or absent pedal pulses; aortic valve regurgitation (AVR); aortic dissection; tortuous or aneurysmal descending thoracic or abdominal aorta; and patients unable to be systemically heparinized. IABP therapy does not prohibit the use of other medications often used in AMI patients, including aspirin, systemic heparinization, angiotensin-converting enzyme inhibitors, intravenous nitroglycerine, and beta blockers. Complications of IABP therapy may include limb ischemia and hemorrhage to the femoral access site. A recently developed technique of sheathless insertion may reduce the rate of limb ischemia [5].

Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement

Abstract: David Moher and colleagues introduce PRISMA, an update of the QUOROM guidelines for reporting systematic reviews and meta-analyses

Preferred reporting items for systematic reviews and meta-analyses: the PRISMA Statement.

Abstract: Systematic reviews and meta-analyses have become increasingly important in health care. Clinicians read them to keep up to date with their field,1,2 and they are often used as a starting point for developing clinical practice guidelines. Granting agencies may require a systematic review to ensure there is justification for further research,3 and some health care journals are moving in this direction.4 As with all research, the value of a systematic review depends on what was done, what was found, and the clarity of reporting. As with other publications, the reporting quality of systematic reviews varies, limiting readers' ability to assess the strengths and weaknesses of those reviews. Several early studies evaluated the quality of review reports. In 1987, Mulrow examined 50 review articles published in 4 leading medical journals in 1985 and 1986 and found that none met all 8 explicit scientific criteria, such as a quality assessment of included studies.5 In 1987, Sacks and colleagues6 evaluated the adequacy of reporting of 83 meta-analyses on 23 characteristics in 6 domains. Reporting was generally poor; between 1 and 14 characteristics were adequately reported (mean = 7.7; standard deviation = 2.7). A 1996 update of this study found little improvement.7 In 1996, to address the suboptimal reporting of meta-analyses, an international group developed a guidance called the QUOROM Statement (QUality Of Reporting Of Meta-analyses), which focused on the reporting of meta-analyses of randomized controlled trials.8 In this article, we summarize a revision of these guidelines, renamed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses), which have been updated to address several conceptual and practical advances in the science of systematic reviews (Box 1). Box 1 Conceptual issues in the evolution from QUOROM to PRISMA

Measuring inconsistency in meta-analyses

Abstract: Cochrane Reviews have recently started including the quantity I 2 to help readers assess the consistency of the results of studies in meta-analyses. What does this new quantity mean, and why is assessment of heterogeneity so important to clinical practice? Systematic reviews and meta-analyses can provide convincing and reliable evidence relevant to many aspects of medicine and health care.1 Their value is especially clear when the results of the studies they include show clinically important effects of similar magnitude. However, the conclusions are less clear when the included studies have differing results. In an attempt to establish whether studies are consistent, reports of meta-analyses commonly present a statistical test of heterogeneity. The test seeks to determine whether there are genuine differences underlying the results of the studies (heterogeneity), or whether the variation in findings is compatible with chance alone (homogeneity). However, the test is susceptible to the number of trials included in the meta-analysis. We have developed a new quantity, I 2, which we believe gives a better measure of the consistency between trials in a meta-analysis. Assessment of the consistency of effects across studies is an essential part of meta-analysis. Unless we know how consistent the results of studies are, we cannot determine the generalisability of the findings of the meta-analysis. Indeed, several hierarchical systems for grading evidence state that the results of studies must be consistent or homogeneous to obtain the highest grading.2–4 Tests for heterogeneity are commonly used to decide on methods for combining studies and for concluding consistency or inconsistency of findings.5 6 But what does the test achieve in practice, and how should the resulting P values be interpreted? A test for heterogeneity examines the null hypothesis that all studies are evaluating the same effect. The usual test statistic …