Plasminogen Degradation by Neutrophil Elastase in Pleural Infection, Not High Plasminogen Activator Inhibitor-1 (PAI-1), is the Cause of Intrapleural Lytic Failure

BACKGROUND

Complex pleural space infections often require treatment with multiple doses of intrapleural tissue-plasminogen activator(tPA) and deoxyribonuclease(DNase), with treatment failure frequently necessitating surgery. Pleural infections are rich in neutrophils, and neutrophil elastase degrades plasminogen, the target substrate of tPA, that is required to generate fibrinolysis. We hypothesized that pleural fluid from patients with pleural space infection would have high elastase activity, evidence of inflammatory plasminogen degradation, and low fibrinolytic potential in response to tPA that could be rescued with plasminogen supplementation.

RESEARCH QUESTION

Does neutrophil elastase degradation of plasminogen contribute to intrapleural fibrinolytic failure?

STUDY DESIGN AND METHODS

We obtained infected pleural fluid and circulating plasma from hospitalized adults(n=10) with IRB approval from a randomized trial evaluating intrapleural fibrinolytics versus surgery for initial management of pleural space infections. Samples were collected pre-intervention, post-intervention day-1(PID1), PID2, and PID3. Activity assays, enzyme-linked immunosorbent assays, and western blot(WB) analysis were performed, and turbidometric measurements of fibrinolysis were performed on pleural fluid +/- exogenous plasminogen supplementation. Results are reported as median(Q1, Q3) or n(%) as appropriate, with alpha set at 0.05.

RESULTS

Pleural fluid elastase activity was >4-fold higher(p=0.02) and plasminogen antigen levels >3-fold lower(p=0.04) than their corresponding plasma. Pleural fluid WB analysis demonstrated abundant plasminogen degradation fragments consistent with elastase degradation patterns. We found that plasminogen-activator inhibitor-1(PAI-1), the native tPA inhibitor, had high antigen levels pre-intervention but the overwhelming majority of this PAI-1(82%) was not active(p=0.003), and all PAI-1 activity was lost by PID2 in patients receiving intrapleural tPA/DNase. Finally, using turbidity clot lysis assays we found that 9 of 10 patients' pleural fluid was unable to generate a significant fibrinolytic response when challenged with tPA and that plasminogen supplementation rescued fibrinolysis in all patients.

INTERPRETATION

Inflammatory plasminogen deficiency, not high PAI-1 activity, is a significant contributor to intrapleural fibrinolytic failure.

Venous excess ultrasonography (VExUS) captures dynamic changes in volume status surrounding hemodialysis: A multicenter prospective observational study

Background

The evaluation of volume status is essential to clinical decision-making, yet multiple studies have shown that physical exam does not reliably estimate a patient's intravascular volume. Venous excess ultrasound score (VExUS) is an emerging volume assessment tool that utilizes inferior vena cava (IVC) diameter and pulse-wave Doppler waveforms of the portal, hepatic and renal veins to evaluate venous congestion. A point-of-care ultrasound exam initially developed by Beaubein-Souligny et al., VExUS represents a reproducible, non-invasive and accurate means of assessing intravascular congestion. VExUS has recently been validated against RHC-the gold-standard of hemodynamic evaluation for volume assessment. While VExUS scores were shown to correlate with elevated cardiac filling pressures (i.e., right atrial pressure (RAP) and pulmonary capillary wedge pressure (PCWP)) at a static point in time, the ability of VExUS to capture dynamic changes in volume status has yet to be elucidated. We hypothesized that paired VExUS examinations performed before and after hemodialysis (HD) would reflect changes in venous congestion in a diverse patient population.

Methods

Inpatients with end-stage renal disease undergoing intermittent HD were evaluated with transabdominal VExUS and lung ultrasonography before and following HD. Paired t-tests were conducted to assess differences between pre-HD and post-HD VExUS scores, B-line scores and dyspnea scores.

Results

Fifty-six patients were screened for inclusion in this study. Ten were excluded due to insufficient image quality or incomplete exams, and forty-six patients (ninety-two paired ultrasound exams) were included in the final analysis. Paired t-test analysis of pre-HD and post-HD VExUS scores revealed a mean VExUS grade change of 0.82 (p<0.001) on a VExUS scale ranging from 0 to 4. The mean difference in B-line score following HD was 0.8 (p=0.001). There was no statistically significant difference in subjective dyspnea score (p=0.41).

Conclusions

Large-volume fluid removal with HD was represented by changes in VExUS score, highlighting the utility of the VExUS exam to capture dynamic shifts in intravascular volume status. Future studies should evaluate change in VExUS grade with intravenous fluid or diuretic administration, with the ultimate goal of evaluating the capacity of a standardized bedside ultrasound protocol to guide inpatient volume optimization.

Effective hemodynamic monitoring

Hemodynamic monitoring is the centerpiece of patient monitoring in acute care settings. Its effectiveness in terms of improved patient outcomes is difficult to quantify. This review focused on effectiveness of monitoring-linked resuscitation strategies from: (1) process-specific monitoring that allows for non-specific prevention of new onset cardiovascular insufficiency (CVI) in perioperative care. Such goal-directed therapy is associated with decreased perioperative complications and length of stay in high-risk surgery patients. (2) Patient-specific personalized resuscitation approaches for CVI. These approaches including dynamic measures to define volume responsiveness and vasomotor tone, limiting less fluid administration and vasopressor duration, reduced length of care. (3) Hemodynamic monitoring to predict future CVI using machine learning approaches. These approaches presently focus on predicting hypotension. Future clinical trials assessing hemodynamic monitoring need to focus on process-specific monitoring based on modifying therapeutic interventions known to improve patient-centered outcomes.

Study of Alteplase for Respiratory Failure in SARS-CoV-2 COVID-19: A Vanguard Multicenter, Rapidly Adaptive, Pragmatic, Randomized Controlled Trial

Background

Pulmonary vascular microthrombi are a proposed mechanism of COVID-19 respiratory failure. We hypothesized that early administration of tissue plasminogen activator (tPA) followed by therapeutic heparin would improve pulmonary function in these patients.

Research Question

Does tPA improve pulmonary function in severe COVID-19 respiratory failure, and is it safe?

Study Design and Methods

Adults with COVID-19-induced respiratory failure were randomized from May14, 2020 through March 3, 2021, in two phases. Phase 1 (n = 36) comprised a control group (standard-of-care treatment) vs a tPA bolus (50-mg tPA IV bolus followed by 7 days of heparin; goal activated partial thromboplastin time [aPTT], 60-80 s) group. Phase 2 (n = 14) comprised a control group vs a tPA drip (50-mg tPA IV bolus, followed by tPA drip 2 mg/h plus heparin 500 units/h over 24 h, then heparin to maintain aPTT of 60-80 s for 7 days) group. Patients were excluded from enrollment if they had not undergone a neurologic examination or cross-sectional brain imaging within the previous 4.5 h to rule out stroke and potential for hemorrhagic conversion. The primary outcome was Pao₂ to Fio₂ ratio improvement from baseline at 48 h after randomization. Secondary outcomes included Pao₂ to Fio₂ ratio improvement of > 50% or Pao₂ to Fio₂ ratio of ≥ 200 at 48 h (composite outcome), ventilator-free days (VFD), and mortality.

Results

Fifty patients were randomized: 17 in the control group and 19 in the tPA bolus group in phase 1 and eight in the control group and six in the tPA drip group in phase 2. No severe bleeding events occurred. In the tPA bolus group, the Pao₂ to Fio₂ ratio values were significantly (P < .017) higher than baseline at 6 through 168 h after randomization; the control group showed no significant improvements. Among patients receiving a tPA bolus, the percent change of Pao₂ to Fio₂ ratio at 48 h (16.9% control [interquartile range (IQR), –8.3% to 36.8%] vs 29.8% tPA bolus [IQR, 4.5%-88.7%]; P = .11), the composite outcome (11.8% vs 47.4%; P = .03), VFD (0.0 [IQR, 0.0-9.0] vs 12.0 [IQR, 0.0-19.0]; P = .11), and in-hospital mortality (41.2% vs 21.1%; P = .19) did not reach statistically significant differences when compared with those of control participants. The patients who received a tPA drip did not experience benefit.

Interpretation

The combination of tPA bolus plus heparin is safe in severe COVID-19 respiratory failure. A phase 3 study is warranted given the improvements in oxygenation and promising observations in VFD and mortality.

Trial Registry

ClinicalTrials.gov; No.: NCT04357730; URL: www.clinicaltrials.gov

11 Frailty and the Rate of Fractures in Patients Initiated on Antihypertensive Medication

Introduction

There is concern regarding adverse effects of antihypertensive treatment, including falls and subsequent fractures, especially hip fractures. As frailty is increasingly recognised as an important risk factor for adverse outcomes, we examined its relationship to fracture rates in older patients after starting antihypertensives.

Methods

Using the Clinical Practice Research Datalink (CPRD), we identified participants over 65-years old starting a first-line antihypertensive medication. Using deficits identified in CPRD we classified patient-level frailty as “Fit”, “Mild”, “Moderate” or “Severe” using the Electronic Frailty Index. We calculated the rate of fractures by frailty level and fracture site, and determined the rate ratio (RR) of first fracture by frailty level, adjusting for confounding, using multivariable poisson regression. We conducted sensitivity analyses to additionally adjust for ethnicity, deprivation, and bisphosphonate use.

Results

44% of participants were classified as mildly frail or greater, but frail participants experienced 58% of all fractures, and 63% of hip fractures. The whole cohort showed a crude rate of 14.1 fractures/1000 person-years, with 4.5 hip fractures/1000 person-years. In severe frailty, this rises to 51.0 fractures/1000 person-years, and 17.7 hip fractures/1000 person-years. After adjustment for confounding, increasing frailty was associated with greater rate of any fracture, reaching RR 2.85 (95% confidence interval 2.43–3.33) for severe frailty versus fit. Results were unchanged in sensitivity analyses.

Conclusions

Frailty and fracture are both common in older participants who start antihypertensive medications. Increasing frailty was positively associated with increased rates of fracture. Clinicians need awareness of this relationship to consider fracture risk assessment and prevention in these patients.

Validation of current procedural terminology codes for surgical stabilization of rib fractures

INTRODUCTION

Current procedural terminology (CPT) codes for surgical stabilization of rib fractures (SSRF) are based solely on the number of ribs fixed, tricotomized at 1-3, 4-6, and ≥ 7. Our objective was to validate CPT codes against operative time at our institution, as well as further stratify complexity by rib fracture location and surgical approach. The purpose of this study is to validate the current CPT coding schema for SSRF, and to identify potential modifiers that are associated with increased case complexity. We hypothesized that operative time is associated with CPT code, number of fractures repaired, exposure technique, and fracture location.

METHODS

Retrospective review of SSRF cases from October 2010 to March 2020. The primary outcome was the length of the operation (minutes). Predictor variables were CPT code, number of fractures repaired (grouped similarly to CPT codes), fractures repaired:ribs repaired ratio > 1, fracture location (sub-scapular vs. other), and positioning/exposure (supine, lateral, prone, and multiple). Kaplan-Meier time-to-event analyses were used to assess relationship with operative time.

RESULTS

188 patients underwent repair of 904 fractures. Operative time was significantly associated with both number of ribs repaired and number of fractures repaired (p<0.01). Although operative time varied significantly by CPT group (p<0.01), there was no significant difference between the 4-6 rib and the ≥ 7 rib groups (p = 0.33). By contrast, each group was significantly different from the others when organized by number of fractures repaired (p = 0.04). Operative time was significantly longer when the fractures repaired:ribs repaired ratio was > 1 (p<0.01), even after stratifying by number of ribs repaired. Both multiple positions/exposures (p<0.01), and repair of ≥ 1 sub-scapular fracture (p<0.01) were significantly associated with operative time.

CONCLUSION

Number of fractures repaired provided a more accurate estimation of operative time as compared to number of ribs repaired. Based on these data, we recommend altering the CPT schema for SSRF to involve number of fractures repaired, with modifiers for both multiple positions/exposures and repair of sub-scapular fractures.

Impact of Electronic Hand Hygiene Monitoring on Hospital-Acquired Clostridium difficile Infection Rates

Background

Lower rates of hand hygiene adherence are linked to increased risk of nosocomial transmission of infectious pathogens, thereby increasing morbidity and mortality. Assessing true adherence is difficult using direct observation due to the low number of observations collected, heterogeneous observer training and bias, and the Hawthorne effect. We assessed whether radio frequency identification (RFID) hand hygiene monitoring resulted in changes to our hospital-onset Clostridium difficile (HO-CDI) rates. We also assessed whether electronically measured hand hygiene improved by the end of the intervention period.

Methods

The RFID system was installed in Apr 2016 in 2 medical/surgical units, a progressive care unit, and an intensive-care unit (study group). Registered nurses, certified nursing assistants, and selected physicians wore RFID badges to track hand hygiene adherence. Adherence is defined as washing with soap or alcohol-based hand rub within 1 minute before or after entering or exiting a patient’s room. A second set of rooms (1 ICU, 1 short-stay unit, and 5 medical/surgical units) without the system served as the control group. HO-CDI rates were tracked monthly for each group using NHSN definitions. HO-CDI trends were compared for 15 months before and 12 months after installation of the system using interrupted time series analysis. Average electronic hand hygiene adherence for the first two months and last two months of the intervention period was compared using the Wilcoxon rank-sum test. Other interventions aimed at reducing HO-CDI were consistently applied to both the study and control groups.

Results

One hundred and eighty-six HO-CDI occurred: 73 in the study group and 113 in the control group. In the study group, the trend in HO-CDI rates changed from increasing in the pre-intervention to decreasing in the post-intervention (P = 0.02) (Figure 1). HO-CDI rates in the control group demonstrated no change in trend (P = 0.69) (Figure 2). In the study group, electronically tracked hand hygiene adherence increased from a mean of 46% in Apr-May 2016, to 77% in Feb-Mar 2017 (P &lt; 0.0001).

Conclusion

Electronic RFID hand hygiene systems can have a tangible effect on hospital-acquired infection rates. This result strengthens the argument for using these systems to improve patient safety.

Disclosures

All authors: No reported disclosures.

The impact of tailored intervention services on charges and mortality for adult super-utilizers

BACKGROUND

Interventions designed to improve care and reduce costs for patients with the highest rates of hospital utilization (super-utilizers) continue to proliferate, despite conflicting evidence of cost savings.

METHODS

We evaluated a practice transformation intervention that implemented team-based care and risk-stratification to match specific primary care resources based on need. This included an intensive outpatient clinic for super-utilizers. We used multivariate regression and a difference-in-differences approach to compare changes in mortality, utilization, and charges between the intervention group and a historical control. Sensitivity analyses tested the robustness of findings and revealed the inherent challenges associated with quasi-experimental designs.

RESULTS

Observed charges for the intervention group were significantly lower than expected charges as derived by the trend of the historical control (p<0.04) resulting in total charge avoidance of approximately $26 million. While inpatient admissions were significantly higher (p<0.01), charges associated with total inpatient (p=0.01), intensive-care unit (p<0.05, not robust to sensitivity analyses), and surgery (p<0.01) were significantly lower than expected in the intervention group. One year mortality was significantly less in the intervention group (12.6% vs 11.5%, p<0.01).

CONCLUSIONS

The use of tailored services, including a dedicated intensive outpatient clinic, for super-utilizers within a larger primary care practice transformation reduced mortality and provided significant savings, even while total hospitalizations increased. These savings were achieved through a reduction in the intensity of inpatient services. The unexpected finding of a reduction in ICU charges deserves further exploration.

IMPLICATIONS

These findings suggest that intensity of inpatient service, and not merely volume of services, should be considered a focus for future intervention design and evaluated as an outcome.

LEVEL OF EVIDENCE

Level III (Quasi-Experimental Design).

Disinfection byproduct formation during biofiltration cycle: Implications for drinking water production

The goal of this study was to investigate the potential of biofiltration to reduce the formation potential of disinfection byproducts (DBPs). Particularly, the work investigates the effect of the duration of the filter cycle on the formation potential of total trihalomethanes (TTHM) and five species of haloacetic acids (HAA5), dissolved oxygen (DO), organic carbon, nitrogen and total phosphorous concentrations along with biofilm coverage of the filter media and biomass viability of the attached cells. The study was conducted on a full-scale biologically active filter, with anthracite and sand media, at the Britannia water treatment plant (WTP), located in Ottawa, Ontario, Canada. The formation potential of both TTHMs and HAA5s decreased due to biofiltration. However the lowest formation potentials for both groups of DBPs and or their precursors were observed immediately following a backwash event. Hence, the highest percent removal of DBPs was observed during the early stages of the biofiltration cycle, which suggests that a higher frequency of backwashing will reduce the formation of DBPs. Variable pressure scanning electron microscopy (VPSEM) analysis shows that biofilm coverage of anthracite and sand media increases as the filtration cycle progressed, while biomass viability analysis demonstrates that the percentage of cells attached to the anthracite and sand media also increases as the filtration cycle progresses. These results suggest that the development and growth of biofilm on the filters increases the DPB formation potential.

The effect of sibutramine prescribing in routine clinical practice on cardiovascular outcomes: a cohort study in the United Kingdom

BACKGROUND/OBJECTIVES

The marketing authorization for the weight loss drug sibutramine was suspended in 2010 following a major trial that showed increased rates of non-fatal myocardial infarction and cerebrovascular events in patients with pre-existing cardiovascular disease. In routine clinical practice, sibutramine was already contraindicated in patients with cardiovascular disease and so the relevance of these influential clinical trial findings to the 'real World' population of patients receiving or eligible for the drug is questionable. We assessed rates of myocardial infarction and cerebrovascular events in a cohort of patients prescribed sibutramine or orlistat in the United Kingdom.

SUBJECTS/METHODS

A cohort of patients prescribed weight loss medication was identified within the Clinical Practice Research Datalink. Rates of myocardial infarction or cerebrovascular event, and all-cause mortality were compared between patients prescribed sibutramine and similar patients prescribed orlistat, using both a multivariable Cox proportional hazard model, and propensity score-adjusted model. Possible effect modification by pre-existing cardiovascular disease and cardiovascular risk factors was assessed.

RESULTS

Patients prescribed sibutramine (N=23,927) appeared to have an elevated rate of myocardial infarction or cerebrovascular events compared with those taking orlistat (N=77,047; hazard ratio 1.69, 95% confidence interval 1.12-2.56). However, subgroup analysis showed the elevated rate was larger in those with pre-existing cardiovascular disease (hazard ratio 4.37, 95% confidence interval 2.21-8.64), compared with those with no cardiovascular disease (hazard ratio 1.52, 95% confidence interval 0.92-2.48, P-interaction=0.0076). All-cause mortality was not increased in those prescribed sibutramine (hazard ratio 0.67, 95% confidence interval 0.34-1.32).

CONCLUSIONS

Sibutramine was associated with increased rates of acute cardiovascular events in people with pre-existing cardiovascular disease, but there was a low absolute risk in those without. Sibutramine's marketing authorization may have, therefore, been inappropriately withdrawn for people without cardiovascular disease.

Corticosteroid use in the intensive care unit: a survey of intensivists

OBJECTIVE

The efficacy of systemic corticosteroids in many critical illnesses remains uncertain. Our primary objective was to survey intensivists in North America about their perceived use of corticosteroids in clinical practice.

DESIGN

Self-administered paper survey.

POPULATION

Intensivists in academic hospitals with clinical trial expertise in critical illness.

MEASUREMENTS

We generated questionnaire items in focus groups and refined them after assessments of clinical sensibility and test-retest reliability and pilot testing. We administered the survey to experienced intensivists practicing in selected North American centres actively enrolling patients in the multicentre Oscillation for ARDS Treated Early (OSCILLATE) Trial (ISRCTN87124254). Respondents used a four-point scale to grade how frequently they would administer corticosteroids in 14 clinical settings. They also reported their opinions on 16 potential near-absolute indications or contraindications for the use of corticosteroids.

MAIN RESULTS

Our response rate was 82% (103/125). Respondents were general internists (50%), respirologists (22%), anesthesiologists (21%), and surgeons (7%) who practiced in mixed medical-surgical units. A majority of respondents reported almost always prescribing corticosteroids in the setting of significant bronchospasm in a mechanically ventilated patient (94%), recent corticosteroid use and low blood pressure (93%), and vasopressor-refractory septic shock (52%). Although more than half of respondents stated they would almost never prescribe corticosteroids in severe community-acquired pneumonia (81%), acute lung injury (ALI, 76%), acute respiratory distress syndrome (ARDS, 65%), and severe ARDS (51%), variability increased with severity of acute lung injury. Near-absolute indications selected by most respondents included known adrenal insufficiency (99%) and suspicion of cryptogenic organizing pneumonia (89%), connective tissue disease (85%), or other potentially corticosteroid-responsive illnesses (85%).

CONCLUSIONS

Respondents reported rarely prescribing corticosteroids for ALI, but accepted them for bronchospasm, suspected adrenal insufficiency due to previous corticosteroid use, and vasopressor-refractory septic shock. These competing indications will complicate the design and interpretation of any future large-scale trial of corticosteroids in critical illness.

Long-term responses of rainforest erosional systems at different spatial scales to selective logging and climatic change

Long-term (21-30 years) erosional responses of rainforest terrain in the Upper Segama catchment, Sabah, to selective logging are assessed at slope, small and large catchment scales. In the 0.44 km(2) Baru catchment, slope erosion measurements over 1990-2010 and sediment fingerprinting indicate that sediment sources 21 years after logging in 1989 are mainly road-linked, including fresh landslips and gullying of scars and toe deposits of 1994-1996 landslides. Analysis and modelling of 5-15 min stream-suspended sediment and discharge data demonstrate a reduction in storm-sediment response between 1996 and 2009, but not yet to pre-logging levels. An unmixing model using bed-sediment geochemical data indicates that 49 per cent of the 216 t km(-2) a(-1) 2009 sediment yield comes from 10 per cent of its area affected by road-linked landslides. Fallout (210)Pb and (137)Cs values from a lateral bench core indicate that sedimentation rates in the 721 km(2) Upper Segama catchment less than doubled with initially highly selective, low-slope logging in the 1980s, but rose 7-13 times when steep terrain was logged in 1992-1993 and 1999-2000. The need to keep steeplands under forest is emphasized if landsliding associated with current and predicted rises in extreme rainstorm magnitude-frequency is to be reduced in scale.

Severity of acute illness is associated with baseline readiness to change in medical intensive care unit patients with unhealthy alcohol use

BACKGROUND

Unhealthy alcohol use predisposes to multiple conditions that frequently result in critical illness and is present in up to one-third of patients admitted to a medical intensive care unit (ICU). We sought to determine the baseline readiness to change in medical ICU patients with unhealthy alcohol use and hypothesized that the severity of acute illness would be independently associated with higher scores on readiness to change scales. We further sought to determine whether this effect is modified by the severity of unhealthy alcohol use.

METHODS

We performed a cross-sectional observational study of current regular drinkers in 3 medical ICUs. The Alcohol Use Disorders Identification Test was used to differentiate low-risk and unhealthy alcohol use and further categorize patients into risky alcohol use or an alcohol use disorder. The severity of a patient's acute illness was assessed by calculating the Acute Physiologic and Chronic Health Evaluation II (APACHE II) score at the time of admission to the medical ICU. Readiness to change was assessed using standardized questionnaires.

RESULTS

Of 101 medical ICU patients who were enrolled, 65 met the criteria for unhealthy alcohol use. The association between the severity of acute illness and readiness to change depended on the instrument used. A higher severity of illness measured by APACHE II score was an independent predictor of readiness to change as assessed by the Stages of Change Readiness and Treatment Eagerness Scale (Taking Action scale; p < 0.01). When a visual analog scale was used to assess readiness to change, there was a significant association with severity of acute illness (p < 0.01) that was modified by the severity of unhealthy alcohol use (p = 0.04 for interaction term).

CONCLUSIONS

Medical ICU patients represent a population where brief interventions require further study. Studies of brief intervention should account for the severity of acute illness and the severity of unhealthy alcohol use as potential effect modifiers.

Early identification of patients at risk of acute lung injury: evaluation of lung injury prediction score in a multicenter cohort study

RATIONALE

Accurate, early identification of patients at risk for developing acute lung injury (ALI) provides the opportunity to test and implement secondary prevention strategies.

OBJECTIVES

To determine the frequency and outcome of ALI development in patients at risk and validate a lung injury prediction score (LIPS).

METHODS

In this prospective multicenter observational cohort study, predisposing conditions and risk modifiers predictive of ALI development were identified from routine clinical data available during initial evaluation. The discrimination of the model was assessed with area under receiver operating curve (AUC). The risk of death from ALI was determined after adjustment for severity of illness and predisposing conditions.

MEASUREMENTS AND MAIN RESULTS

Twenty-two hospitals enrolled 5,584 patients at risk. ALI developed a median of 2 (interquartile range 1-4) days after initial evaluation in 377 (6.8%; 148 ALI-only, 229 adult respiratory distress syndrome) patients. The frequency of ALI varied according to predisposing conditions (from 3% in pancreatitis to 26% after smoke inhalation). LIPS discriminated patients who developed ALI from those who did not with an AUC of 0.80 (95% confidence interval, 0.78-0.82). When adjusted for severity of illness and predisposing conditions, development of ALI increased the risk of in-hospital death (odds ratio, 4.1; 95% confidence interval, 2.9-5.7).

CONCLUSIONS

ALI occurrence varies according to predisposing conditions and carries an independently poor prognosis. Using routinely available clinical data, LIPS identifies patients at high risk for ALI early in the course of their illness. This model will alert clinicians about the risk of ALI and facilitate testing and implementation of ALI prevention strategies. Clinical trial registered with www.clinicaltrials.gov (NCT00889772).

Prophylactic heparin in patients with severe sepsis treated with drotrecogin alfa (activated)

RATIONALE

Patients with severe sepsis frequently receive prophylactic heparin during drotrecogin alfa (activated) (DrotAA) treatment due to risk of venous thromboembolic events (VTEs). Biological plausibility exists for heparin to reduce DrotAA efficacy and/or increase bleeding.

OBJECTIVES

Primary: demonstrate in adult patients with severe sepsis receiving DrotAA treatment that 28-day mortality was equivalent for patients treated with concomitant prophylactic heparin compared with placebo; secondary: safety and VTE incidence.

METHODS

International, randomized, double-blind, phase 4, equivalence-design trial (n = 1994). Patients were eligible if indicated for and receiving DrotAA treatment under the country's approved label. Study drug (low molecular weight/unfractionated heparin) or placebo (saline) was administered every 12 hours during DrotAA infusion (24 ug/kg/hr for 96 hr). In patients on baseline heparin and randomized to placebo, heparin was stopped.

MEASUREMENTS AND MAIN RESULTS

Twenty-eight-day mortality was not equivalent between treatment groups. Heparin mortality was numerically lower (28.3 vs. 31.9%; p = 0.08). In the prospectively defined subgroup of patients exposed to heparin at baseline, patients receiving placebo experienced higher mortality (35.6 vs. 26.9%; p = 0.005). For safety, significant differences were observed during Days 0-6 for any bleeding event (placebo, n = 78; heparin, n = 105; p = 0.049) and ischemic stroke during Days 0-6 (placebo, n = 12; heparin, n = 3; p = 0.02) and Days 0-28 (placebo, n = 17; heparin, n = 5; p = 0.009). The VTE rate was low, with no statistical difference between groups (0-6 d, p = 0.60; 0-28 d, p = 0.26).

CONCLUSIONS

Compared with placebo, concomitant prophylactic heparin was not equivalent, did not increase 28-day mortality, and had an acceptable safety profile in patients with severe sepsis receiving DrotAA. Heparin discontinuation should be carefully weighed in patients considered for DrotAA treatment. XPRESS clinical trial registered with www.clinicaltrials.gov (NCT 00049777). The study ID numbers are 6743; F1K-MC-EVBR.

Hyponatremia: why it matters, how it presents, how we can manage it

Hyponatremia is a common electrolyte disorder among hospitalized patients and has been associated with increased mortality. Most patients are asymptomatic, but many do present with symptoms, usually of a generalized neurologic nature. Based-on medical history, physical examination (including volume-status assessment), and laboratory tests, patients can be classified as having either hypervolemic, euvolemic, or hypovolemic hyponatremia. Management depends on the speed of hyponatremia onset; its degree, duration, and symptoms; and whether there are risk factors for neurologic complications. The risks of overly rapid correction must be weighed against the benefits of treating hyponatremia. Traditional therapies have significant limitations. New agents that antagonize arginine vasopressin at the V2 receptor or both the V(1A) and V2 receptors show promise for treating hypervolemic and euvolemic hyponatremia, as they induce desired free water diuresis without inducing sodium excretion.

Active screening in high-risk units is an effective and cost-avoidant method to reduce the rate of methicillin-resistant Staphylococcus aureus infection in the hospital

OBJECTIVE

To evaluate the impact of active screening for methicillin-resistant Staphylococcus aureus (MRSA) on MRSA infection rates and cost avoidance in units where the risk of MRSA transmission is high.

METHODS

During a 15-month period, all patients admitted to our adult medical and surgical intensive care units (ICUs) were screened for MRSA nasal carriage on admission and weekly thereafter. The overall rates of all MRSA infections and of nosocomial MRSA infection in the 2 adult ICUs and the general wards were compared with rates during the 15-month period prior to the start of routine screening. The percentage of patients colonized or infected with MRSA on admission and the cost avoidance of the surveillance program were also assessed.

RESULTS

The overall rate of MRSA infections for all 3 areas combined decreased from 6.1 infections per 1,000 census-days in the preintervention period to 4.1 infections per 1,000 census-days in the postintervention period (P = .01). The decrease remained statistically significant when only nosocomial MRSA infections were examined (4.5 vs 2.8 infections per 1,000 census-days; P < .01), despite a corresponding increase during the postintervention period in the percentage of patients with onset of MRSA infection in the first 72 hours after admission to the general wards (46% to 81%; P < .005). A total of 3.7% of ICU patients were colonized or infected with MRSA on admission; MRSA would not have been detected in 91% of these patients if screening had not been performed. At a cost of Dollars 3,475/month for the program, we averted a mean of 2.5 MRSA infections/month for the ICUs combined, avoiding Dollars 19,714/month in excess cost in the ICUs.

CONCLUSIONS

Even in a setting of increasing community-associated MRSA, active MRSA screening as part of a multi-factorial intervention targeted to high-risk units may be an effective and cost-avoidant strategy for achieving a sustained decrease of MRSA infections throughout the hospital.

HMGB1 contributes to the development of acute lung injury after hemorrhage

High mobility group box 1 (HMGB1) is a novel late mediator of inflammatory responses that contributes to endotoxin-induced acute lung injury and sepsis-associated lethality. Although acute lung injury is a frequent complication of severe blood loss, the contribution of HMGB1 to organ system dysfunction in this setting has not been investigated. In this study, HMGB1 was detected in pulmonary endothelial cells and macrophages under baseline conditions. After hemorrhage, in addition to positively staining endothelial cells and macrophages, neutrophils expressing HMGB1 were present in the lungs. HMGB1 expression in the lung was found to be increased within 4 h of hemorrhage and then remained elevated for more than 72 h after blood loss. Neutrophils appeared to contribute to the increase in posthemorrhage pulmonary HMGB1 expression since no change in lung HMGB1 levels was found after hemorrhage in mice made neutropenic with cyclophosphamide. Plasma concentrations of HMGB1 also increased after hemorrhage. Blockade of HMGB1 by administration of anti-HMGB1 antibodies prevented hemorrhage-induced increases in nuclear translocation of NF-kappa B in the lungs and pulmonary levels of proinflammatory cytokines, including keratinocyte-derived chemokine, IL-6, and IL-1 beta. Similarly, both the accumulation of neutrophils in the lung as well as enhanced lung permeability were reduced when anti-HMGB1 antibodies were injected after hemorrhage. These results demonstrate that hemorrhage results in increased HMGB1 expression in the lungs, primarily through neutrophil sources, and that HMGB1 participates in hemorrhage-induced acute lung injury.

Parsimonious modelling of water and suspended sediment flux from nested catchments affected by selective tropical forestry

The ability to model the suspended sediment flux (SSflux) and associated water flow from terrain affected by selective logging is important to the establishment of credible measures to improve the ecological sustainability of forestry practices. Recent appreciation of the impact of parameter uncertainty on the statistical credibility of complex models with little internal state validation supports the use of more parsimonious approaches such as data-based mechanistic (DBM) modelling. The DBM approach combines physically based understanding with model structure identification based on transfer functions and objective statistical inference. Within this study, these approaches have been newly applied to rainfall-SSflux response. The dynamics of the sediment system, together with the rainfall-river flow system, were monitored at five nested contributory areas within a 44 ha headwater region in Malaysian Borneo. The data series analysed covered a whole year at a 5 min resolution, and were collected during a period some five to six years after selective timber harvesting had ceased. Physically based and statistical interpretation of these data was possible given the wealth of contemporary and past hydrogeomorphic data collected within the same region. The results indicated that parsimonious, three-parameter models of rainfall-river flow and rainfall-SSflux for the whole catchment describe 80 and 90% of the variance, respectively, and that parameter changes between scales could be explained in physically meaningful terms. Indeed, the modelling indicated some new conceptual descriptions of the river flow and sediment-generation systems. An extreme rainstorm having a 10-20 year return period was present within the data series and was shown to generate new mass movements along the forestry roads that had a differential impact on the monitored contributory areas. Critically, this spatially discrete behaviour was captured by the modelling and may indicate the potential use of DBM approaches for (i) predicting the differential effect of alternative forestry practices, (ii) estimating uncertainty in the behaviour of ungauged areas and (iii) forecasting river flow and SSflux in terrain with temporal changes in rainfall regime and forestry impacts.

The role of extreme events in the impacts of selective tropical forestry on erosion during harvesting and recovery phases at Danum Valley, Sabah

Ten years' hydrological investigations at Danum have provided strong evidence of the effects of extremes of drought, as in the April 1992 El Niño southern oscillation event, and flood, as in January 1996. The 1.5 km2 undisturbed forest control catchment experienced a complete drying out of the stream for the whole 1.5 km of defined channel above the gauging station in 1992, but concentrated surface flow along every declivity from within a few metres of the catchment divide after the exceptional rains of 19 January 1996. Under these natural conditions, erosion is episodic. Sediment is discharged in pulses caused by storm events, collapse of debris dams and occasional landslips. Disturbance by logging accentuates this irregular regime. In the first few months following disturbance, a wave of sediment is moved by each storm, but over subsequent years, rare events scour sediment from bare areas, gullies and channel deposits. The spatial distribution of sediment sources changes with time after logging, as bare areas on slopes are revegetated and small gullies are filled with debris. Extreme storm events, as in January 1996, cause logging roads to collapse, with landslides leading to surges of sediment into channels, reactivating the pulsed sediment delivery by every storm that happened immediately after logging. These effects are not dampened out with increasing catchment scale. Even the 721 km2 Sungai Segama has a sediment yield regime dominated by extreme events, the sediment yield in that single day on 19 January 1996 exceeding the annual sediment load in several previous years. In a large disturbed catchment, such road failures and logging-activity-induced mass movements increase the mud and silt in floodwaters affecting settlements downstream. Management systems require long-term sediment reduction strategies. This implies careful road design and good water movement regulation and erosion control throughout the logging process.

Hydrological investigations of forest disturbance and land cover impacts in South-East Asia: a review

Investigations of land management impacts on hydrology are well developed in South-East Asia, having been greatly extended by national organizations in the last two decades. Regional collaborative efforts, such as the ASEAN-US watershed programme, have helped develop skills and long-running monitoring programmes. Work in different countries is significant for particular aspects: the powerful effects of both cyclones and landsliding in Taiwan, the significance of lahars in Java, of small-scale agriculture in Thailand and plantation establishment in Malaysia. Different aid programmes have contributed specialist knowledge such as British work on reservoir sedimentation, Dutch, Swedish and British work on softwood plantations and US work in hill-tribe agriculture. Much has been achieved through individual university research projects, including PhD and MSc theses. The net result is that for most countries there is now good information on changes in the rainfall-run-off relationship due to forest disturbance or conversion, some information on the impacts on sediment delivery and erosion of hillslopes, but relatively little about the dynamics and magnitude of nutrient losses. Improvements have been made in the ability to model the consequences of forest conversion and of selective logging and exciting prospects exist for the development of better predictions of transfer of water from the hillslopes to the stream channels using techniques such as multilevel modelling. Understanding of the processes involved has advanced through the detailed monitoring made possible at permanent field stations such as that at Danum Valley, Sabah.

ECSIT is an evolutionarily conserved intermediate in the Toll/IL-1 signal transduction pathway

Activation of NF-kappaB as a consequence of signaling through the Toll and IL-1 receptors is a major element of innate immune responses. We report the identification and characterization of a novel intermediate in these signaling pathways that bridges TRAF6 to MEKK-1. This adapter protein, which we have named ECSIT (evolutionarily conserved signaling intermediate in Toll pathways), is specific for the Toll/IL-1 pathways and is a regulator of MEKK-1 processing. Expression of wild-type ECSIT accelerates processing of MEKK-1, whereas a dominant-negative fragment of ECSIT blocks MEKK-1 processing and activation of NF-kappaB. These results indicate an important role for ECSIT in signaling to NF-kappaB and suggest that processing of MEKK-1 is required for its function in the Toll/IL-1 pathway.

Fas activates NF-κB and induces apoptosis in T-cell lines by signaling pathways distinct from those induced by TNF-α

The p55 tumor necrosis factor (TNF) receptor and the Fas (CD95/APO-1) receptor share an intracellular domain necessary to induce apoptosis, suggesting they utilize common signaling pathways. To define pathways triggered by Fas and TNF-alpha we utilized human CEM-C7 T-cells. As expected, stimulation of either receptor induced apoptosis and TNF-alpha-induced signaling included the activation of NF-kappaB. Surprisingly, Fas-induced signaling also triggered the activation of NF-kappaB in T cells, yet the kinetics of NF-kappaB induction by Fas was markedly delayed. NF-kappaB activation by both pathways was persistent and due to the sequential degradation of IkappaB-alpha and IkappaB-beta. However, the kinetics of IkappaB degradation were different and there were differential effects of protease inhibitors and antioxidants on NF-kappaB activation. Signaling pathways leading to activation of apoptosis were similarly separable and were also independent of NF-kappaB activation. Thus, the Fas and TNF receptors utilize distinct signal transduction pathways in T-cells to induce NF-kappaB and apoptosis.

Eosinophil chemotaxis inhibited by 5-lipoxygenase blockade and leukotriene receptor antagonism

We studied the effects of the 5-lipoxygenase inhibition and sulfidopeptidyl leukotriene receptor antagonism on lumenal chemotaxis of eosinophils in 124 guinea pig tracheal explant preparations from 62 animals. Cell migration was assessed histologically and by differential cell count, and airway narrowing was measured by calibrated micrometry. Intralumenal instillation of the chemotaxin, formyl-met-leu-phe (FMLP) caused migration of 163,509 +/- 18,103 eosinophils/cm segment (eos/cm) versus 15,443 +/- 3,557 eos/cm for segments receiving vehicle only (p < 0.001). Coincubation of FMLP with zileuton, a selective inhibitor of 5-lipoxygenase, caused a concentration-related inhibition of eosinophil migration. At 10(-10) M zileuton, cell migration caused by FMLP was decreased by 57% and nearly complete reduction to 17,200 +/- 3,620 eos/cm resulted after 10(-6) M zileuton (p < 0.001 versus FMLP). Lumenal narrowing caused by FMLP (15.3 +/- 3.4%) was attenuated maximally to 1.15 +/- 2.51% after 10(-8) M zileuton (p < 0.02). In 36 preparations, concentration of leukotriene B4 (LTB4) was measured in treated tracheal perfusate. LTB4 secretion caused by FMLP was 6.4 +/- 0.48 pg/ml versus 3.32 +/- 0.89 pg/ml for buffer control at 5 min (p < 0.02) and was undetectable 120 min after activation with FMLP. Blockade of LTB4-receptor with the selective antagonist, LTB4 dimethyl amide, caused > 90% inhibition of eosinophil migration (p < 0.001). Comparable results were obtained with zafirlukast, an LTD4-receptor antagonist. Our data demonstrate that both LTB4 and LTD4 facilitate eosinophil migration from lamina propria to lumen caused by the chemotaxin, FMLP, and that LTB4-induced eosinophil migration is accompanied by initial lumenal secretion of LTB4.

Early cleavage to formation of the unilaminar blastocyst in the marsupial Antechinus stuartii: ultrastructure

The development of Antechinus stuartii from the 2-cell stage to the blastocyst stage in vivo was examined by routine transmission electron microscopy. The 2-8-cell stages had a similar organization of organelles, whereas the 16- to 32-cell stages had pluriblast cells and trophoblast cells forming an epithelium closely apposed to the zona pellucida. Specialized cell-zona plugs were formed at the 8-cell stage, and primitive cell junctions appeared in later conceptuses. The cytoplasmic organelles included mitochondria, lysosomes, aggregates of smooth endoplasmic reticulum, lipid and protein yolk bodies and fibrillar arrays, possibly contractile in function. Nuclei had uniformly-dispersed dense chromatin. Nucleoli of 2-4-cell conceptuses were dense, compact and fibrillar, and those of 8-cell conceptuses and later conceptuses were finely granular and became progressively reticulated. The embryonic genome is probably not switched on before the 8-cell stage. Sperm tails were detected in cells in several early conceptuses. The yolk mass had the same organelles as cells. Centrioles were discovered for the first time in marsupial conceptuses. These were prominently situated at a spindle pole in a 32-cell blastomere and were associated with a nucleus and sperm tail at the 4-cell stage. It is very likely that the paternal centrosome is inherited at fertilization and perpetuated in Antechinus embryos during cleavage.

Quantitation of the cytosolic phospholipase A2 (type IV) in isolated human peripheral blood eosinophils by sandwich-ELISA

Sandwich enzyme-linked immunosorbent assay (sELISA) was developed for precise quantitation of cytosolic phospholipase A2 (cPLA2 type IV) concentration in isolated human peripheral blood eosinophils as an alternative to semiquantitative chemiluminescent assay employing immunoprecipitation/Western blot analysis. In this assay, monoclonal mouse anti-human cPLA2 antiserum was used as the capture antibody, polyclonal rabbit anti-human cPLA2 antiserum as the secondary antibody, and alkaline phosphatase-conjugated goat anti-rabbit IgG as the tertiary, reporter antibody. Purified human cPLA2 (0-1000 ng/ml) dissolved in Tris-HCl buffered saline was used as the standard protein. The detection limit for cPLA2 in 10(6) eosinophils was 0.109 ng/ml, and coefficients of inter- and intra-assay variation were 4.23% and 7.07%, respectively. There was no cross-reactivity with other (secretory) isoforms of PLA2 (sPLA2 types I-III) either from porcine pancreas, human synovial fluid, or bee venom. In separate studies, the recovery of cPLA2 was > 83% when eosinophil lysate was supplemented exogenously with two different concentrations of cPLA2. From a total protein content of 22.3 +/- 1.7 micrograms/10(6) cells, the baseline concentration of cPLA2 was 0.38 +/- 0.18 ng/10(6) cells in eosinophils obtained from mildly atopic donors. Immunoblotting studies confirmed the complete specificity for the type IV isoform as detected by sELISA. This sELISA method permits the precise quantitative assessment of cPLA2 in nanogram quantities per million cells, which has not previously been possible by immunoblotting analysis.

Role of unphosphorylated, newly synthesized I kappa B beta in persistent activation of NF-kappa B

Stimulation with inducers that cause persistent activation of NF-kappa B results in the degradation of the NF-kappa B inhibitors, I kappa B alpha and I kappa B beta. Despite the rapid resynthesis and accumulation of I kappa B alpha, NF-kappa B remains induced under these conditions. We now report that I kappa B beta is also resynthesized in stimulated cells and appears as an unphosphorylated protein. The unphosphorylated I kappa B beta forms a stable complex with NF-kappa B in the cytosol; however, this binding fails to mask the nuclear localization signal and DNA binding domain on NF-kappa B, and the I kappa B beta-NF-kappa B complex enters the nucleus. It appears therefore that during prolonged stimulation, I kappa B beta functions as a chaperone for NF-kappa B by protecting it from I kappa B alpha and allowing it to be transported to the nucleus.

A sustained reduction in IkappaB-beta may contribute to persistent NF-kappaB activation in human endothelial cells

The responses of vascular endothelial cells (EC) to tumor necrosis factor-alpha (TNF), interleukin-1alpha (IL-1), and phorbol myristate acetate (PMA) were compared with respect to the kinetics of (i) NF-kappaB activation, (ii) IkappaB-alpha and IkappaB-beta degradation, and (iii) NF-kappaB-dependent cell surface molecule expression. TNF rapidly (</=20 min) and persistently (>20 h) activates NF-kappaB; IL-1 rapidly activates NF-kappaB, but activity declines by 3 h and further by 20 h; PMA slowly and transiently activates NF-kappaB. Untreated EC contain the inhibitory proteins IkappaB-alpha and IkappaB-beta. The onset of NF-kappaB activation correlates with degradation of IkappaB-alpha, but IkappaB-alpha reappears by 4 h without resequestration of NF-kappaB. TNF causes a rapid but partial (50%) reduction in IkappaB-beta, which does not recover by 22 h; IL-1 and PMA cause slower and less sustained reductions in IkappaB-beta. All three agonists induce de novo expression of E-selectin (CD62E) and vascular cell adhesion molecule-1 (CD106) and increase expression of intercellular adhesion molecule-1 (CD54) at 4 h. TNF induces sustained increases in vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 and increases human leukocyte antigen class I molecules at 24 h. We conclude that TNF causes persistent activation of NF-kappaB in human EC and that this may result from sustained reductions in IkappaB-beta levels.

Focus on board effectiveness

In its ongoing effort to promote and ensure the highest quality of health care throughout Canada, The Canadian Hospital Association has entered into a partnership with The Centre for Quality in Governance, a Toronto-based non-profit organization formed in 1992. The Centre's mandate is to improve the effectiveness of organizations by researching and evaluating various aspects of governance.

The 44P subunit of the T4 DNA polymerase accessory protein complex catalyzes ATP hydrolysis

The genes encoding all three T4 DNA polymerase accessory proteins have been cloned into overexpression plasmids. Induction of cells harboring these plasmids results in the synthesis of each accessory protein at levels that approach 10% of the total cellular protein. The solubility of the accessory proteins after induction at 42 degrees C ranges from about 60% to greater than 95%. A plasmid that allows overexpression of the 44P/62P complex has been manipulated further to overexpress selectively the 44P subunit without 62P, permitting us to assess how each subunit contributes to the properties of the 44P/62P complex. A comparison of 44P and 44P/62P by conventional hydrodynamic techniques shows that 44P forms a subcomplex nearly as large as the 44P/62P complex. In addition, 44P catalyzes DNA-dependent ATP hydrolysis with a specific activity similar to that of the 44P/62P ATPase. However, unlike the 44P/62P complex, the ATPase activity of 44P alone is only slightly stimulated by 45P. This suggests that one role of the 62P subunit is to facilitate a productive interaction of 44P and 45P.

The effect of food on the oral administration of 6-mercaptopurine

The effect of food on the bioavailability of 6-mercaptopurine (6-MP) has been investigated. Seven patients were studied on two separate occasions. On the first occasion 6-MP was administered p.o. after an overnight fast and on the second, 15 min after a standard breakfast. 6-MP concentrations were determined by high-performance liquid chromatography. Variable plasma drug levels were observed between individual subjects in the fasting state. The peak levels of 6-MP were lower and took longer to be achieved following administration after a standard breakfast than after an overnight fast. In two subjects levels were undetectable (less than 20 ng/ml). In view of these observations it is suggested that 6-MP should be administered before food if maximum blood levels are to be achieved.