The concentration-dependent effects of ethanol on Caenorhabditis elegans behaviour.

The effects of ethanol on the brain are concentration dependent. Low concentrations (mM) intoxicate, while greater than 100 mM anaesthetize. Of most relevance to human alcohol addiction are mechanisms of intoxication. Previously, Caenorhabditis elegans has been employed in genetic screens to define effectors of intoxication. Here, we inform interpretation of these studies by providing evidence that ethanol rapidly equilibriates across C. elegans cuticle. Importantly, the effect of ethanol on muscle activity rapidly reaches steady-state, and the concentration-dependence of the effect is very similar in intact animals and exposed muscle. Thus the cuticle does not present an absorption barrier for ethanol, and furthermore the internal concentration is likely to approach that applied externally. Thus, modelling intoxication in C. elegans requires exposure to external ethanol less than 100 mM. Furthermore, the permeability of the cuticle to ethanol enables analysis of precisely controlled concentration-dependent effects of acute, chronic, and episodic ethanol exposure on behaviour.

Relationship of cerebral perfusion pressure levels to outcome in traumatic brain injury.

This study examined the relationship of cumulative percent time that cerebral perfusion pressure (CPP) fell below set thresholds to outcome in individuals with traumatic brain injury (TBI). The sample included 157 patients (16 to 89 years of age, 79%, male) admitted to an intensive care unit at an academic medical center who underwent invasive arterial blood pressure and intracranial pressure monitoring. CPP levels were recorded continuously during the first 96 hours of monitoring. Initial neurologic status was assessed using the post-resuscitation Glasgow Coma Scale. Outcome was evaluated at hospital discharge and at six months post-injury using the Extended Glasgow Outcome Scale (GOSE). The relationship of cumulative periods of low CPP to outcome was evaluated using hierarchical and binary logistic regression analysis, controlling for age, gender, and injury severity. Patients experiencing less cumulative percent time below specific CPP thresholds were more likely to have better outcome at discharge (55 mm Hg, p = .004; 60 mm Hg, p = .008; 65 mm Hg, p = .024; 70 mm Hg, p = .016). Although differences in GOSE scores at six months were not significant, those with less time below CPP thresholds were more likely to survive. Accumulated episodes of low CPP had a stronger negative relationship with outcome in patients with more severe primary brain injury.

Information technology and CPP management in neuro intensive care.

This study developed and tested the acceptability of a computer interface intended to provide better information about CPP to Neuro Intensive Care nurses. Maintaining adequate CPP is crucial in preventing secondary brain injury, yet current monitoring data displays have poor ergonomics that minimize usable information for clinicians. Information systems developmental methods were used to 1) formulate the model for CPP information display, 2) develop the system with end-users, and 3) install the system in the Neuro Intensive Care Unit. System testing for effects on clinicians and patient outcomes is occurring in a randomized clinical trial. Metaphor graphic and universal graphic displays were tested with 37 staff nurses from three intensive care units using continuous ICP monitoring. Nursing staff preferred an augmented universal data display to the metaphor graphics, endorsing a modified trend area graph with threshold-dependent properties. The preferred model was programmed in Visual Basic and installed on small computers that were randomly allocated as live or blank displays to beds of newly admitted head injury or aneurysmal subarachnoid hemorrhage patients with continuous monitoring. Nursing acceptability of the information interface was achieved through the use of end-user focus groups that resulted in modifying the metaphor graphic approach to a more readily understandable one.

Cerebral autoregulation and outcome in acute brain injury.

The purpose of this study was to examine the relationship between Czosnyka and others' Pressure Reactivity Index (PRx) and neurologic outcome in patients with acute brain injury, including traumatic brain injury (TBI) and cerebrovascular pathology. PRx measures the correlation between arterial blood pressure and intracranial pressure waves and may reflect cerebral autoregulation in response to blood pressure changes. A negative PRx reflects intact cerebrovascular response, whereas a positive PRx reflects impaired response. Positive PRx has been shown to correlate with poorer outcome in individuals with TBI, but these findings have not been confirmed by replication in other studies, nor have PRx values been reported for individuals with cerebrovascular pathology. In this study, PRx was determined in 52 patients with TBI (n = 27) or cerebrovascular pathology (n = 25). Hierarchical linear regression was used to evaluate the contribution of PRx to outcome, controlling for age and Glasgow Coma Scale score. Analysis of all subjects together did not support the previously reported relationship between PRx and outcome. However, for those with TBI, positive PRx was a significant predictor of negative outcome (P = 0.03). For those with cerebrovascular pathology, the effect was not significant (P = 0.10) and was in the opposite direction. For individuals with TBI, PRx may provide useful information related to cerebral autoregulation that is predictive of outcome. The meaning of PRx in individuals with cerebrovascular pathology is unclear, and further study is needed to examine the paradoxical findings observed.

Intracranial pressure waveform analysis: clinical and research implications.

Assessment of intracranial adaptive capacity is vital in critically ill individuals with acute brain injury because there is the potential that nursing care activities and environmental stimuli to result in clinically significant increases in intracranial pressure (ICP) in a subset of individuals with decreased intracranial adaptive capacity. ICP waveform analysis provides information about intracranial dynamics that can help identify individuals who have decreased adaptive capacity and are at risk for increases in ICP and decreases in cerebral perfusion pressure, which may contribute to secondary brain injury and have a negative impact on neurologic outcome. The ability to identify high-risk individuals allows nurses to initiate interventions targeted at decreasing adaptive demand or increasing adaptive capacity in these individuals. Changes in the ICP waveform occur under various physiologic and pathophysiologic conditions and may provide valuable information about intracranial adaptive capacity. Simple visual assessment of the ICP waveform for increased amplitude and P2 elevation is clinically relevant and has been found to provide a rough indicator of decreased adaptive capacity. Advanced ICP waveform analysis techniques warrant further study as a means of dynamically assessing intracranial adaptive capacity.

Quality pain management outcomes: the power of place.

This study explores how an organization, as the context of care, influences nursing practice and a nursing-sensitive, quality health outcome-pain management. The results provide important insights into organizational patterns associated with favorable pain management-related outcomes as well as the congruence between and among subunits within the organization. Outcomes were most favorable on units where nurses had attitudes supportive of aggressive pain management and higher levels of coordination and discretion.

Association between nurse-physician collaboration and patient outcomes in three intensive care units.

OBJECTIVE: To investigate the association of collaboration between intensive care unit (ICU) physicians and nurses and patient outcome. DESIGN: Prospective, descriptive, correlational study using self-report instruments. SETTINGS: A community teaching hospital medical ICU, a university teaching hospital surgical ICU, and a community non-teaching hospital mixed ICU, all in upstate New York. SUBJECTS: Ninety-seven attending physicians, 63 resident physicians, and 162 staff nurses. PROCEDURE: When patients were ready for transfer from the ICU to an area of less intensive care, questionnaires were used to assess care providers' reports of collaboration in making the transfer decision. After controlling for severity of illness, the association between interprofessional collaboration and patient outcome was assessed. Unit-level organizational collaboration and patient outcomes were ranked. MEASURES: Healthcare providers' reported levels of collaboration, patient severity of illness and individual risk, patient outcomes of death or readmission to the ICU, unit-level collaboration, and unit patient risk of negative outcome. MAIN RESULTS: Medical ICU nurses' reports of collaboration were associated positively with patient outcomes. No other associations between individual reports of collaboration and patient outcome were found. There was a perfect rank order correlation between unit-level organizational collaboration and patient outcomes across the three units. CONCLUSIONS: The study offered some support for the importance of physician-nurse collaboration in ICU care delivery, a variable susceptible to intervention and further study.

Rethinking physiologic stability: touch and intracranial pressure.

The purpose of this research was to examine the contingent nature of physiologic stability with respect to the impact of nursing and parental care touch on intracranial pressure (ICP) in children. Data were reanalyzed from those previously collected in eight children in a pediatric intensive care unit who had intracranial hypertension from a variety of causes and whose ICP was invasively monitored. One hundred forty-nine clusters of spontaneous touch/talking were available for analysis after those occurring close in time to procedures and drugs affecting ICP were dropped. Twenty-three episodes of investigator touch (without talking) were also analyzed. ICP stability was defined as any tracing over a defined time period in which the peak-to-trough amplitude did not exceed twice the calculated resting variability. Such an approach allowed classification and counting of stable versus unstable baselines, and stable versus unstable responses to touch. Therefore, ICP stability was examined by comparing the stability of the ICP tracing the last minute prior to a cluster of nonprocedural touch (baseline) with the first minute after the cluster. Clusters of spontaneous touch were nearly always associated with talking to the child and rarely were followed by change in level of ICP greater than that child's ICP variability at rest. Investigator stroking without talking never was followed by a significant change in level of ICP. There was a contingent relationship between stability of the ICP tracing prior to a cluster of touching/talking such that the probability of ICP becoming more stable when the touch/talk occurred on an unstable baseline was twice that of touch/talk occurring on an stable baseline.

Quality health outcomes model. American Academy of Nursing Expert Panel on Quality Health Care.

PURPOSE: Donabedian's 1966 framework of structure, process, and outcome has guided three decades of study in the United States of the elements needed to evaluate and compare medical care quality. Donabedian's perspective was essentially linear, assuming that structures affect processes, which in turn affect outcomes. Patient characteristics are sometimes considered as mediating outcomes and clinical interventions are considered to be processes. A model is presented in the following article that relates multiple factors affecting quality of care to desired outcomes. It extends previous models by positing dynamic relationships with indicators that not only act upon, but reciprocally affect the various components. SCOPE AND SOURCES: The proposed model was derived from a synthesis of the authors' experience in quality of care practice and research, as well as selected previous theories. CONCLUSIONS: The quality health outcomes model is sufficiently broad (a) to guide development of databases for quality improvement and outcomes management, (b) to suggest key variables in clinical intervention research, and (c) to provide a framework for outcomes research and outcomes management that compares not only treatment options, but organizational or system level interventions. The model also has several policy implications.

Adverse outcomes and variations in organization of care delivery.

OBJECTIVES: This article evaluates the state of the science with respect to morbidity, mortality, and adverse effects as outcomes indicative of variations in organizational variables in care delivery systems. METHODS: Eighty-one research papers research examining relations among organizational structures or processes and mortality/adverse effects were reviewed, assembled from electronic and manual searches of the biomedical and health services research literature. RESULTS: Most research relating mortality and other adverse outcomes to organizational variables has been conducted in acute care hospitals since 1990, with these outcome indicators linked more frequently to organizational structures than to organizational or clinical processes. There is support in some studies, but not in others, that nursing surveillance, quality of working environment, and quality of interaction with other professionals distinguish hospitals with lower mortality and complications from those with higher rates of these adverse effects. Increasing sophistication of risk adjustment methods suggests that variations in mortality and complications are influenced by patient variables more than by organizational variables. Adverse events may be a more sensitive marker of differences in organizational quality in acute care hospitals and long-term care. CONCLUSIONS: Taken together, the acute care studies are not conclusive regarding the extent to which the organizational features of care delivery systems positively influence such bottom-line outcomes as mortality. As severity-adjustment methods become more refined for hospital patients, many of the small differences currently seen in mortality and complications may disappear. However, given that adverse events appear more closely related to organizational factors than in mortality, researchers need to refine and better define such events that are logically related to the coordinative organizational processes among caregivers. Finally, researchers need to go much beyond mortality, morbidity, and adverse events in evaluating the linkage between the organization of care and outcomes.

Advanced practice and neuroscience nursing.

In this report Calkin's model of advanced practice is used to contrast generalized/specialized and basic/advanced nursing practices. Examples of specialized and advanced practices in neuroscience nursing are described in the context of environmental forces that influence advanced practice in North America. Finally, a letter from the future is used to speculate and to illustrate visions of nursing practice in the twenty-first century.

Critical care outcomes: linking structures, processes, and organizational and clinical outcomes.

BACKGROUND: Organizational structure and process are thought to affect patient care outcomes beyond the effects of expert clinical care. OBJECTIVES: To test the hypothesis that a discretionary pattern of organizational structure and process factors is predictive of critical care unit performance, ie, desirable patient and organizational outcomes. METHODS: Quality-of-care patient and organizational outcomes were evaluated in 25 critical care units. A single value representing each critical care unit's euclidian distance from a theoretically ideal pattern of discretionary function was determined and correlated with unit-level measures of outcomes (standardized mortality ratio, severity-adjusted length of stay, patient satisfaction, quality of nursing care, and nursing retention). RESULTS: Distance from the ideal-type discretionary pattern predicted organizational but not clinical outcomes. Units closer to the ideal-type pattern had higher RN retention, and were viewed as better places to work, with higher-quality care by both nurses and physicians. Objectively measured quality of care, patient satisfaction, severity-adjusted mortality, and length of stay were not consistently related to better-structured units. CONCLUSIONS: With experienced critical care practitioners, unit-level structure and process factors were better predictors of organizational outcomes than of clinical outcomes.