Neurogenesis or non-neurogenesis: that is the question

Neural stem/precursor cells (NPCs) that reside within germinal niches of the adult CNS have more complex roles than previously expected. In addition to their well-documented neurogenic functions, emerging evidence indicates that NPCs exert non-neurogenic functions that contribute to the regulation and preservation of tissue homeostasis under both physiological and pathological conditions. In this issue of the JCI, Mohammad et al. found that DCs efficiently patrol the CNS only when the germinal niche of the subventricular zone functions properly. Indeed, DCs traveled from the ventricles along the rostral migratory stream to the olfactory bulb (a cervical lymph node access point) to dampen anti-CNS immune responses. The authors’ findings further support a non-neurogenic role for NPCs in maintaining tissue homeostasis and promoting tissue protection in the adult brain.     

To wake-up,or not to wake-up: that is the Hamletic neurocritical care question!

The need for a reliable neurological evaluation in severely brain-injured patients conflicts with sedation, which is routinely administered. Helbok and colleagues prospectively evaluated in a small cohort of 20 sedated severely brain-injured patients the effects of a wakeup test on intracranial pressure (ICP), brain tissue oxygen tension and brain metabolism. The test has been considered potentially risky on 34% of the study days. When the test is performed, ICP and cerebral perfusion pressure increase, usually slightly, except in a subgroup of patients with lower cerebral compliance where marked ICP and cerebral perfusion pressure changes were recorded. In this cohort, the information gained with the wake-up test has been negligible. Given the current little knowledge about the benefits of interruption of continuous sedation in brain-injured patients, it is extremely important to adopt multiple monitoring modalities in neurocritical care in order to escape wake-up tests in those patients who will potentially be harmed by this procedure. Once the clinical condition will improve, sedation needs to be tapered and suspended as soon as possible.     

To transform or not transform skewed data for psychometric analysis: that is the question!

BACKGROUND: Although data transformation is generally recommended, its benefits of have not been widely studied. This report reviews evidence regarding the costs and benefits of transforming skewed data with respect to two statistics commonly used in psychometric analyses: the Cronbach alpha and the Pearson product-moment correlation. METHODS: Data describing 758 immigrants from the former Soviet Union who completed a Russian language version of the Symptom Checklist-90-Revised (SCL-90-R) were used to demonstrate the effects of transformation. More than half (55%) of the SCL-90-R items had a problematic skew. The Cronbach alpha and the Pearson product-moment correlation were calculated for original item responses as well as for square root and log transformations of these responses. Sample size (full, 30%, 20%), transformation type (square root or log transformation), and transformation method (sum items first and then transform, transform items first and then sum) were manipulated to evaluate the relevance of these factors to transformation. RESULTS: Regardless of sample size, neither the Cronbach alpha nor the Pearson product-moment correlation showed a difference between original and transformed data, with one exception. When items were transformed first before being summed in the calculation of the Pearson product-moment correlation, inconsistently higher (+.05) or slightly lower values (-.01) were observed relative to those created with the nontransformed data across the different sample sizes. CONCLUSIONS: These findings suggest that data transformation is not always needed or advisable when the Cronbach alpha or Pearson product-moment correlation is calculated for instruments with skewed item responses.     

Bolus or continuous hydrocortisone – that is the question

Constantly evolving treatment guidelines based on a growing body of randomized controlled trials are helping us to improve outcomes in sepsis. However, it must be borne in mind that proven benefit from individual sepsis treatments does not guarantee synergistic beneficial effects when new treatments are added to sepsis management. Indeed, unexpected harmful interactions are also possible. A good example of this is the conflict between intensive insulin therapy and 'low dose' hydrocortisone in septic shock. The goal of tight glycaemic control is made more complicated by steroid-induced hyperglycaemia. In their recent study, Loisa and coworkers demonstrate a measure that reduces the risk for this interaction. They found continuous infusion of hydrocortisone to be associated with fewer hyperglycaemic episodes and reduced staff workload compared with bolus application.     

To resolve or confront, that is the question

Learn to address behavioral concerns in an efficient, proactive manner.     

Evidence-based practice: to be or not to be, this is the question!

Evidence‐based nursing is the current fashion. It is being touted as the mechanism to achieve best practice in the clinical setting. But while evidence‐based practice (EBP) is being presented in the literature, discussed at nursing practice forums, and evidence‐based centres of excellence have developed, there seems to be very little impact in the practice that nurses deliver on a daily basis. The case in point is the collection of vital signs. While not historically a nursing skill, over the last 60 years it has become an integral component of practice in the postoperative general surgical setting. The evidence to support these practices is scant. Policies and text purport traditional routine‐regulated practice without substantive evidence to support their claims. These polices are being used to control rather than support EBP. In conjunction with the traditional practice of vital sign collection and the culture of the clinical settings, the policies are limiting opportunities for clinicians to make individual decisions about care delivery based on the unique needs of each patient. Rather than focusing on EBP as the solution to the development of best practice, is it not time to change the focus to real strategies that will assist in achieving best practice? These include the creation of rigorous relevant evidence, the valuing of clinical expertise and the changing of the cultures in which nurses develop and practice.