Impact of an Emergency Department-to-Home Transitional Care Intervention on Health Service Use in Medicare Beneficiaries: A Mixed Methods Study.

BACKGROUND: Hospital-based acute care [emergency department (ED) visits and hospitalizations] that is preventable with high-quality outpatient care contributes to health care system waste and patient harm. OBJECTIVE: To test the hypothesis that an ED-to-home transitional care intervention reduces hospital-based acute care in chronically ill, older ED visitors. RESEARCH DESIGN: Convergent, parallel, mixed-methods design including a randomized controlled trial. SETTING: Two diverse Florida EDs. SUBJECTS: Medicare fee-for-service beneficiaries with chronic illness presenting to the ED. INTERVENTION: The Coleman Care Transition Intervention adapted for ED visitors. MEASURES: The main outcome was hospital-based acute care within 60 days of index ED visit. We also assessed office-based outpatient visits during the same period. RESULTS: The Intervention did not significantly reduce return ED visits or hospitalizations or increase outpatient visits. In those with return ED visits, the Intervention Group was less likely to be hospitalized than the Usual Care Group. Interview themes describe a cycle of hospital-based acute care largely outside patients' control that may be difficult to interrupt with a coaching intervention. CONCLUSIONS AND RELEVANCE: Structural features of the health care system, including lack of access to timely outpatient care, funnel patients into the ED and hospital admission. Reducing hospital-based acute care requires increased focus on the health care system rather than patients' care-seeking decisions.

A Framework Illustrating Care-Seeking Among Older Adults in a Hospital Emergency Department.

Background and Objectives: Older adults seeking emergency department (ED) care often have multiple, complex chronic conditions. We sought to understand factors that influence ED care-seeking by older adults and present a theoretical framework illustrating this process. Research Design and Methods: In this grounded theory study, we interviewed 40 older adults with chronic illness within 90 days of an ED visit to explore their decision-making about seeking ED care. We also interviewed 10 primary care and ED physicians to explore conditions that influence ED referrals. Interview transcripts were analyzed using constant comparison and dimensional analysis. Results: ED care-seeking among older adults is complex and influenced by multiple internal and external conditions including symptom type, severity, and onset; previous experience with and meaning of similar symptoms; limited access to prompt primary care; social and financial concerns; and deciding if symptoms warranted immediate attention. When contacting their primary care providers (PCPs), patients were often referred to the ED. Discussion and Implications: Older adults seeking ED care make rational and appropriate choices which are often predicated by referrals from their PCPs. Expecting patients to have the requisite knowledge to determine if symptoms require emergency care is unrealistic. ED visits are often the best strategy for patients to receive appropriate care. A healthcare system that provides better continuity between PCPs and the ED, better access to PCPs for urgent care, and timely follow-up care that takes into account the multiple and complex medical and social needs of older community-living adults is needed.

Feasibility of an ED-to-Home Intervention to Engage Patients: A Mixed-Methods Investigation.

INTRODUCTION: Older, chronically ill patients with limited health literacy are often under-engaged in managing their health and turn to the emergency department (ED) for healthcare needs. We tested the impact of an ED-initiated coaching intervention on patient engagement and follow-up doctor visits in this high-risk population. We also explored patients' care-seeking decisions. METHODS: We conducted a mixed-methods study including a randomized controlled trial and in-depth interviews in two EDs in northern Florida. Participants were chronically ill older ED patients with limited health literacy and Medicare as a payer source. Patients were assigned to an evidence-based coaching intervention (n= 35) or usual post-ED care (n= 34). Qualitative interviews (n=9) explored patients' reasons for ED use. We assessed average between-group differences in patient engagement over time with the Patient Activation Measure (PAM) tool, using logistic regression and a difference-in-difference approach. Between-group differences in follow-up doctor visits were determined. We analyzed qualitative data using open coding and thematic analysis. RESULTS: PAM scores fell in both groups after the ED visit but fell significantly more in "usual care" (average decline -4.64) than "intervention" participants (average decline -2.77) (ß=1.87, p=0.043). There were no between-group differences in doctor visits. Patients described well-informed reasons for ED visits including onset and severity of symptoms, lack of timely provider access, and immediate and comprehensive ED care. CONCLUSION: The coaching intervention significantly reduced declines in patient engagement observed after usual post-ED care. Patients reported well-informed reasons for ED use and will likely continue to make ED visits unless strategies, such as ED-initiated coaching, are implemented to help vulnerable patients better manage their health and healthcare.

The Association of Health Literacy With Preventable Emergency Department Visits: A Cross-sectional Study.

BACKGROUND: Policymakers argue that emergency department (ED) visits for conditions preventable with high-quality outpatient care contribute to waste in the healthcare system. However, access to ambulatory care is uneven, especially for vulnerable populations like minorities, the poor, and those with limited health literacy. The impact of limited health literacy on ED visits that are preventable with timely, high-quality ambulatory care is unknown. OBJECTIVE: The objective was to determine the association of health literacy with preventable ED visits. METHODS: We conducted an observational cross-sectional study of potentially preventable ED visits (outcome) among adults (≥18 years old) in an ED serving an urban community. We assessed health literacy (predictor) through structured interviews with the Rapid Estimate of Adult Literacy in Medicine (REALM). We recorded age, sex, race, employment, payer, marital and health status, and number of comorbidities through structured interviews or electronic record review. We identified potentially preventable ED visits in the 2 years before the index ED visit by applying Agency for Healthcare Research and Quality technical specifications to identify ambulatory care sensitive conditions using ED discharge diagnoses in hospital administrative data. We used Poisson regression to evaluate the number of preventable ED visits among patients with limited (REALM < 61) versus adequate (REALM ≥ 61) health literacy after adjusting for covariates. RESULTS: Of 1,201 participants, 709 (59%) were female, 370 (31%) were African American, mean age was 41.6 years, and 394 (33%) had limited health literacy. Of 4,444 total ED visits, 423 (9.5%) were potentially preventable. Of these, 260 (61%) resulted in hospital admission and 163 (39%) were treat and release. After covariates were adjusted for, patients with limited literacy had 2.3 (95% confidence interval [CI] = 1.7-3.1) times the number of potentially preventable ED visits resulting in hospital admission compared to individuals with adequate health literacy, 1.4 (95% CI = 1.0-2.0) times the number of treat-and-release visits, and 1.9 (95% CI = 1.5-2.4) times the number of total preventable ED visits. CONCLUSIONS: Our results suggest that the ED may be an important site to deploy universal literacy-sensitive precautions and to test literacy-sensitive interventions with the goal of reducing the burden of potentially preventable ED visits on patients and the healthcare system.

Measuring quality: caries-related emergency department visits and follow-up among children.

OBJECTIVE: This study validated two Dental Quality Alliance system-level measures of oral healthcare quality for children - caries-related emergency department (ED) visits and timely follow-up of those visits with a dentist - including formal validation of diagnosis codes used to identify caries-related ED visits and measurement of follow-up care. METHODS: The measures were specified for implementation with administrative claims data and validated using data from the Florida and Texas Medicaid and Children's Health Insurance Programs. Measure specification testing and measure score validation used administrative data for 7,007,765 children. We validated the diagnosis codes in claims data by comparisons with manual reviews of 300 records from a Florida hospital ED and calculation of the kappa statistic, sensitivity, and specificity. RESULTS: Overall agreement in caries-related ED visit classifications between the claims data and record reviews was 87.7 percent with kappa = 0.71, sensitivity = 82 percent, and specificity = 90 percent. The calculated measure scores using administrative data found more than four-fold variation between programs with the lowest and highest caries-related ED visit rates (6.90/100,000 member months and 30.68/100,000 member months). The percentage of follow-up visits within 7 days and 30 days ranged from 22-39 percent and 34-49 percent, respectively. CONCLUSIONS: These National Quality Forum endorsed measures provide valid methodologies for assessing the rate of caries-related ED visits, an important system-level outcome indicator of outpatient prevention and disease management, and the timeliness of follow-up with a dentist. There is significant variation in caries-related ED visits among state Medicaid programs, and most ED visits do not have follow-up with a dentist within 30 days.

Adapting Conceptual Frameworks for Patient Engagement in Emergency Department Research.

For many people the emergency department (ED) is the first point of access to healthcare for acute needs and a recurring location for many with chronic healthcare needs. While the ED is well placed to identify unmet needs it can also be a net that people slip through when faced with uncoordinated and expensive healthcare challenges. Thus the ED has a responsibility to set patients on a safe and meaningful care trajectory, which can only be done in consultation and partnership with the patients themselves. The purpose of this article is to present crucial aspects of patient engagement that are essential for future research to foster an environment of colearning and respect that encourages ongoing involvement by patients, families, and staff.

Trends in dental-related use of hospital emergency departments in Florida.

OBJECTIVES: The inability to access regular dental care may lead to care seeking at hospital emergency departments (EDs). However, EDs generally are not equipped or staffed to provide definitive dental services. This study examined trends and patterns of hospital ED use for dental-related reasons in Florida, a large, diverse state with serious barriers to accessing dental care. METHODS: Data for this study were drawn from ambulatory ED discharge records compiled by Florida's Agency for Health Care Administration for 2005-2014. Visits for dental-related reasons in Florida were defined by the patient's reported reason for seeking care or the ED physician's primary diagnosis using ICD-9-CM codes. We calculated frequencies, age-specific and age-adjusted rates per 100,000 population, and secular trends in dental-related ED visits and their associated charges. RESULTS: The number of dental-related visits to Florida EDs increased each year, from 104,642 in 2005 to 163,900 in 2014; the age-adjusted rate increased by 43.6 percent. Total charges for dental-related ED visits in Florida increased more than threefold during this time period, from $47.7 million in 2005 to $193.4 million in 2014 (adjusted for inflation). The primary payers for dental-related ED visits in 2014 were Medicaid (38 percent), self-pay (38 percent), commercial insurance (11 percent), Medicare (8 percent), and other (5 percent). CONCLUSIONS: Dental-related visits to hospital EDs in Florida have increased substantially during the past decade, as have their associated charges. Most patients did not receive definitive oral health care in EDs, and this trend represents an increasingly inefficient use of health care system resources.

Primary Care Experiences of Emergency Department Patients With Limited Health Literacy.

It is unclear why patients with limited health literacy have fewer visits with a personal doctor and more emergency department (ED) visits than patients with adequate health literacy. We identified significant differences in perceived access to a personal doctor and high-quality provider interactions among adults with limited compared to adequate health literacy presenting for emergency treatment. Practice and provider strategies to ensure that patients have timely access to care and high-quality provider interactions may address some of the reasons patients with limited health literacy use more emergency department-based and less preventive care than those with adequate health literacy.

Emergency department crowding and time to antibiotic administration in febrile infants.

INTRODUCTION: Early antibiotic administration is recommended in newborns presenting with febrile illness to emergency departments (ED) to avert the sequelae of serious bacterial infection. Although ED crowding has been associated with delays in antibiotic administration in a dedicated pediatric ED, the majority of children that receive emergency medical care in the United States present to EDs that treat both adult and pediatric emergencies. The purpose of this study was to examine the relationship between time to antibiotic administration in febrile newborns and crowding in a general ED serving both an adult and pediatric population. METHODS: We conducted a retrospective chart review of 159 newborns presenting to a general ED between 2005 and 2011 and analyzed the association between time to antibiotic administration and ED occupancy rate at the time of, prior to, and following infant presentation to the ED. RESULTS: We observed delayed and variable time to antibiotic administration and found no association between time to antibiotic administration and occupancy rate prior to, at the time of, or following infant presentation (p>0.05). ED time to antibiotic administration was not associated with hospital length of stay, and there was no inpatient mortality. CONCLUSION: Delayed and highly variable time to antibiotic treatment in febrile newborns was common but unrelated to ED crowding in the general ED study site. Guidelines for time to antibiotic administration in this population may reduce variability in ED practice patterns.

Potentially preventable use of emergency services: the role of low health literacy.

BACKGROUND: Limited health literacy is a barrier for understanding health information and has been identified as a risk factor for overuse of the emergency department (ED). The association of health literacy with access to primary care services in patients presenting to the ED has not been fully explored. OBJECTIVE: To examine the relationship between health literacy, access to primary care, and reasons for ED use among adults presenting for emergency care. METHODS: Structured interviews that included health literacy assessment were performed involving 492 ED patients at one Southern academic medical center. Unadjusted and multivariable logistic regression models assessed the relationship between health literacy and (1) access to a personal physician; (2) doctor office visits; (3) ED visits; (4) hospitalizations; and (5) potentially preventable hospital admissions. RESULTS: After adjusting for sociodemographic and health status, those with limited health literacy reported fewer doctor office visits [odds ratio (OR)=0.6; 95% confidence interval (CI), 0.4-1.0], greater ED use, (OR=1.6; 95% CI, 1.0-2.4), and had more potentially preventable hospital admissions (OR=1.7; 95% CI, 1.0-2.7) than those with adequate health literacy. After further controlling for insurance and employment status, fewer doctor office visits remained significantly associated with patient health literacy (OR=0.5; 95% CI, 0.3-0.9). Patients with limited health literacy reported a preference for emergency care, as the services were perceived as better. CONCLUSIONS: Among ED patients, limited health literacy was independently associated with fewer doctor office visits and a preference for emergency care. Policies to reduce ED use should consider steps to limit barriers and improve attitudes toward primary care services.

Compliance with outpatient stress testing in low-risk patients presenting to the emergency department with chest pain.

Recent evidence suggests that stress testing prior to emergency department (ED) release in low-risk chest pain patients identifies those who can be safely discharged home. When immediate stress testing is not feasible, rapid outpatient stress testing has been recommended. The objective of this study was to determine compliance rate and incidence of adverse cardiac events in patients presenting to the ED with low-risk chest pain referred for outpatient stress testing. Retrospective chart and social security death index review were conducted in 448 consecutive chest pain patients who presented to a university hospital and level I trauma center between April 30 and December 31, 2007. Patients were evaluated with an accelerated chest pain protocol defined as a 4-hour ED rule out and referral for outpatient stress testing within 72 hours of ED release. Only patients without known cardiac disease, a thrombolysis in myocardial infarction risk score ≤2, negative serial ECGs and cardiac biomarkers, and benign ED course were eligible for the protocol. Primary outcome measures included compliance with outpatient stress testing and documented 30-day incidence of adverse cardiac events following ED release. The social security death index was queried to determine 12-month incidence of all-cause mortality in enrolled patients. Logistic regression analysis of characteristics associated with outpatient stress test compliance was determined and incidence of adverse cardiac events in those who were and were not compliant with outpatient stress testing was compared. Significance was set at P < 0.05. A total of 188 patients (42%) completed outpatient stress testing, but only 27 (6%) completed testing within 72 hours of ED discharge. Compliance was correlated with insurance and race, but not patient age, gender, or thrombolysis in myocardial infarction risk score. No significant differences in adverse cardiac events were documented in patients who did and did not comply with outpatient stress testing. Compliance with outpatient stress testing is poor in low-risk chest pain patients following ED release. Despite poor compliance, the documented incidence of adverse cardiac events in this low-risk cohort was lower than that reported in patients with negative provocative testing prior to ED release.

Emergency Department Activation of Interventional Cardiology to Reduce Door-to-Balloon Time.

BACKGROUND: Despite American College of Cardiology (ACC) and American Heart Association (AHA) guidelines, many hospitals have door-to-balloon times in excess of 90 minutes. Emergency Department (ED) activation of interventional cardiology has been described as an important strategy to reduce door-to-balloon time. However, prior studies on ED activation have been in suburban hospitals with door-to-balloon times near the ACC/AHA targeted times. OBJECTIVE: To determine if ED activation of interventional cardiology could significantly improve reperfusion times and reach the ACC/AHA target of 90 minutes or less in a safety net hospital, a Level I trauma center and teaching hospital serving primarily uninsured and underinsured patient population with door-to-balloon times ranking in the lowest quartile of United States hospitals. METHODS: In this study, door-to balloon times before and after implementation of ED activation were compared by retrospective chart review. RESULTS: Eighty patients were included in the study, 48 before and 32 after ED activation of interventional cardiology. Median door-to-balloon time decreased from 163.5 minutes before to 130 minutes after ED activation, a significant difference of 33.5 minutes (p=0.028). Door-to-balloon time on nights, weekends and holidays decreased from a median of 165.5 minutes to 130 minutes, a reduction of 35.5 minutes, which also reached statistical significance (p=0.029). CONCLUSION: ED activation of interventional cardiology produced a statistically significant reduction in door-to-balloon time. However, the reduction was not enough to achieve a door-to-balloon time of less than 90 minutes. Safety net hospitals with door-to-balloon times in the lowest quartile nationally may require multiple strategies to achieve targeted myocardial reperfusion times.

The number and nature of emergency department encounters in patients with deep brain stimulators.

UNLABELLED: Deep brain stimulation (DBS) has become an increasingly common modality for control of several neurological disorders such as Parkinson's disease, dystonia, essential tremor (ET), and others. Our experience has demonstrated the need for emergency physicians to familiarize themselves with the potential complications of the DBS device as well as the device itself. Therefore, our aim in this paper was to elucidate the number and nature of DBS and non-DBS presentations to the emergency department (ED) and to educate and familiarize ED physicians about DBS devices and their potential complications. We also aimed to devise a simple protocol for DBS management so that all ED physicians would have access to the knowledge or referral capabilities when managing a DBS patient. The objective of the present study was to review the number and nature of ED encounters in patients with deep brain stimulation (DBS) devices implanted for movement and neuropsychiatric disorders. METHODS: The series of encounters reviewed included 215 unique patients with DBS implantation who were identified using an IRB approved database and a paper chart review. Patients in the study included those implanted at University of Florida (UF), as well as those implanted at outside institutions, so long as they were followed at UF. The cohort included n = 215 DBS patients. 25.6% of all 215 patients presented to the ED at least once, with the most common presentation occurring as a result of a decline in mental status when taking into account all visits (6%). Reasons for presentation to the ED included neurological (54.6%), infections/hardware issues (27.9%), orthopedic/focal problems (10.5%), and medical issues (7%). In total, 29 patients arrived at the ED for DBS related issues (23.2%). Of those who presented to the ED (n = 55), the average age was 53.1 (range 10-80 years). Headache was the most common complaint within the neurological category (22.1%), followed by change in mental status (15.1%), and syncope (9.3%). When examining the data by ED diagnosis, change in mental status occurred most commonly in Parkinson's disease (19.6%). Falls were most common in essential tremor (27.2%), and headache occurred most commonly in the dystonia group (52.1%). Across all diseases, mental status change was the most common indication for an ED encounter (6%). Parkinson disease patients most commonly presented with altered mental status (8%), essential tremor patients revealed a high preponderance of falls (6.5%), and dystonia patients tended to present with headache (7.1%). It was concluded that a large number of patients with DBS will present to the ED for many reasons, the majority of which will not be direct complications of their DBS device. Neurological issues were the most common chief complaint, with individual differences depending on the underlying disease. It is important for ED physicians to consider non-DBS related complaints in the presentation of these unique patients since these issues comprise the majority of the ED visits. However, when properly evaluating these patients, management of their DBS device, or referrals to neurosurgery and neurology, if necessary, are imperative. In addition to device management, regular ED standards of care should apply to this special cohort of patients.

Protective effects of low respiratory frequency in experimental ventilator-associated lung injury.

OBJECTIVE: To determine whether ventilator-associated lung hyperinflation injury can be attenuated by a reduction in respiratory frequency. DESIGN: Prospective comparative laboratory investigation. SETTING: University medical center research laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Eight groups of isolated, perfused rat lungs were exposed to cyclic ventilation at different respiratory frequencies and tidal volumes. Each group of six to eight lung preparations was assigned to one of four respiratory frequencies (10, 20, 40, or 80 breaths/min) and one of two tidal volumes (5 or 20 mL.kg). Measurement of capillary filtration coefficient (Kf,c), a sensitive index of lung microvascular permeability and injury, was made at baseline and at 30, 60, and 90 mins of the experimental conditions. MEASUREMENTS AND MAIN RESULTS: Lungs exposed to 5 mL.kg tidal volume had no elevation in Kf,c at any time point regardless of respiratory frequency. Lungs exposed to 20 mL. kg tidal volume and a respiratory frequency of 80 had significant elevations in Kf,c at all times after baseline compared with lungs exposed to respiratory frequencies of 10, 20, or 40 (0.14 +/- 0.03, 0.16 +/- 0.02, 0.31 +/- 0.05 vs. 0.76 +/- 0.16). Furthermore, the Kf,c at 90 mins was significantly higher than permeability at baseline in this group (1.53 +/- 0.45 vs. 0.12 +/- 0.02 mL.min.cm H2O.100 g of lung tissue). CONCLUSIONS: Reduction in respiratory frequency to values much lower than normal ameliorated experimental ventilator-induced hyperinflation lung injury as determined by pulmonary capillary filtration coefficient.

Outcomes of patients not transported after calling 911.

To compare the outcomes of patients who were denied transport by emergency medical services (EMS) with those who refused to be transported, all EMS non-transports were reviewed to determine who refused the transport and adherence to mandatory transport guidelines. Patients were contacted for telephone survey. Of 906 non-transported patients, 310 consented to the survey. Of these, 205 were patient refusals and 105 were EMS refusals. There was no significant difference between the patient and EMS refusal groups in reported change in medical care, hospitalization, or death. One hundred ten non-transported patients met mandatory transport criteria (85 patient refusals vs. 25 EMS refusals, p = 0.002). In conclusion, patient non-transport may result in adverse outcomes that are as likely to occur in patients who are denied transport by EMS as those who refuse to be transported. Patients who refuse transport are more likely to meet mandatory transport guidelines.

Near-infrared spectroscopy: a tool to monitor cerebral hemodynamic and metabolic changes after cardiac arrest in rats.

INTRODUCTION: Cardiac arrest (CA) is associated with poor neurological outcome and is associated with a poor understanding of the cerebral hemodynamic and metabolic changes. The objective of this study was to determine the applicability of near-infrared spectroscopy (NIRS), to observe the changes in cerebral total hemoglobin (T-Hb) reflecting cerebral blood volume, oxygenation state of Hb, oxidized cytochrome oxidase (Cyto-C), and brain water content following CA. METHODS: Fourteen rats were subjected to normothermic (37.5 degrees C) or hypothermic (34 degrees C) CA induced by 8 min of asphyxiation. Animals were resuscitated with ventilation, cardiopulmonary resuscitation (CPR), and epinephrine (adrenaline). Hypothermia was induced before CA. NIRS was applied to the animal head to measure T-Hb with a wavelength of 808 nm (n = 10) and oxygenated/deoxygenated Hb, Cyto-C, and brain water content with wavelengths of 620-1120 nm (n = 4). RESULTS: There were no technical difficulties in applying NIRS to the animal, and the signals were strong and consistent. Normothermic CA caused post-resuscitation hyperemia followed by hypoperfusion determined by the level of T-Hb. Hypothermic CA blunted post-resuscitation hyperemia and resulted in more prominent post-resuscitation hypoperfusion. Both, normothermic and hypothermic CA resulted in a sharp decrease in oxygenated Hb and Cyto-C, and the level of oxygenated Hb was higher in hypothermic CA after resuscitation. There was a rapid increase in brain water signals following CA. Hypothermic CA attenuated increased water signals in normothermic CA following resuscitation. CONCLUSION: NIRS can be applied to monitor cerebral blood volume, oxygenation state of Hb, Cyto-C, and water content following CA in rats.

Cerebral cortical aquaporin-4 expression in brain edema following cardiac arrest in rats.

OBJECTIVES: Brain edema occurs following clinical as well as experimental cardiac arrest (CA) and predicts a poor neurologic outcome. The objective of this study was to determine the expression of cerebral cortex aquaporin (AQP)-4, a member of a family of membrane water-channel proteins, in brain edema formation following normothermic or hypothermic CA. METHODS: Twenty-four rats were subjected to time-matched normothermic (N-Sham, 37.5 degrees C +/- 0.5 degrees C, n = 6) or hypothermic (H-Sham, 34 degrees C +/- 0.5 degrees C, n = 6) sham experiments and normothermic (N-CA, n = 6) or hypothermic (H-CA, n = 6) CA induced by asphyxiation for 8 minutes. Hypothermia was induced before CA. The animals were resuscitated with cardiopulmonary resuscitation, ventilation, and epinephrine administration. Brain edema was determined by brain wet-to-dry weight ratio at one hour of resuscitation. AQP4 immunoactivity in the cerebral cortex was determined using immunohistochemical staining and was semiquantified as an intensity of staining with an automated cell imaging system. RESULTS: Mild hypothermia in the sham experiments did not alter cerebral cortex AQP4 immunoactivity (mean +/- SD) (55.0 +/- 3.7 in H-Sham vs. 53.3 +/- 1.7 in N-Sham, p > 0.05). N-CA resulted in a significant increase in AQP4 immunoactivity (61.8 +/- 4.5) compared with N-Sham (p = 0.01) and H-Sham (p = 0.03). H-CA attenuated AQP4 compared with N-CA (53.4 +/- 1.3, p = 0.01). Brain wet-to-dry weight ratios were 4.41 +/- 0.07 in N-Sham, 4.40 +/- 0.08 in H-Sham (p > 0.05 vs. N-Sham), 4.55 +/- 0.04 in N-CA (p = 0.004 vs. N-Sham; p = 0.005 vs. H-Sham), and 4.43 +/- 0.09 in H-CA (p = 0.02 vs. N-CA; p > 0.05 vs. N-Sham and H-Sham). CONCLUSIONS: Cerebral cortical AQP4 expression is up-regulated after normothermic CA, which is attenuated by hypothermia induced before CA.

Pressure-controlled ventilation attenuates lung microvascular injury in a rat model of activated charcoal aspiration.

BACKGROUND: Previous animal data suggest that aspiration of activated charcoal is associated with pulmonary microvascular injury that may be related to excessive ventilator-induced airway pressures. The purpose of this study was to test the hypothesis that ventilator-induced airway trauma contributes to the lung vascular injury observed following activated charcoal aspiration. METHODS: Capillary filtration coefficient (Kf,c), a sensitive measure of lung microvascular permeability, was determined isogravimetrically prior to and after intratracheal instillation of 0.4 ml/kg (12% weight/vol. solution, pH 7.4) activated charcoal oran equal volume of sterile water in isolated, perfused rat lungs in which ventilation was either pressure-controlled at 10cm H2O or volume-controlled at 5 ml/kg. RESULTS: There was significant lung injury in both activated charcoal groups regardless of ventilation method compared to control lungs or lungs administered sterile water (p < 0.05 ANOVA). However, injury to pressure-controlled ventilated lungs was significantly less than lungs ventilated with traditional, volume-controlled ventilation. CONCLUSION: The results of this investigation demonstrate that pressure-controlled ventilation reduces the lung microvascular injury observed following aspiration of activated charcoal as compared to traditional volume-controlled ventilation methods.

Mild hypothermia induced before cardiac arrest reduces brain edema formation in rats.

OBJECTIVES: The mechanisms by which hypothermia improves cardiac arrest (CA)-induced brain damage are unclear. The authors hypothesized that mild hypothermia induced before CA attenuates brain edema formation by preventing neutrophil-mediated dysfunction of the endothelial cell junction proteins. METHODS: Eighteen rats were randomized to normal control surgery (group 1, n = 6), normothermic (37.5 degrees C) CA (group 2, n = 6), or hypothermic (34 degrees C) CA (group 3, n = 6). Hypothermia was induced with external cooling before CA in group 3. Cardiac arrest was induced by 8 minutes of asphyxiation. Brain edema was determined by wet-to-dry weight ratio and cerebral spinal fluid pressure (CSFP). Brain neutrophil content was determined by myeloperoxidase (MPO) activity, and occludin degradation was assessed by western blotting. RESULTS: Normothermic CA significantly increased brain wet-to-dry weight ratio from 4.52 +/- 0.04 in group 1 to 4.80 +/- 0.04 in group 2 (p = 0.0003) and CSFP from 3.6 +/- 0.9 in group 1 to 8.9 +/- 0.9 mm Hg in group 2 (p = 0.004). Mild hypothermia before CA in group 3 significantly reduced brain wet-to-dry weight ratio (4.68 +/- 0.03, p = 0.008 vs. group 2) and CSFP (3.8 +/- 0.5 mm Hg, p = 0.004 vs. group 2). Cardiac arrest increased brain MPO from 0.07 +/- 0.025 in group 1 to 0.16 +/- 0.02 units/gram brain weight in group 2 (p = 0.006) that was not decreased by hypothermia before CA (0.12 +/- 0.02 in group 3 (p = 0.07 vs. group 2). There was no occludin proteolysis in any group. CONCLUSIONS: Mild hypothermia before CA decreases CA-induced brain edema. The hypothermia-elicited reduction in brain edema does not appear to be neutrophil-dependent and the early brain edema formation may not involve the proteolysis of occludin.