Association of delayed adequate antimicrobial treatment and organ dysfunction in pediatric bloodstream infections

BACKGROUND

Bloodstream infections (BSIs) are associated with significant mortality and morbidity, including multiple organ dysfunction. We explored if delayed adequate antimicrobial treatment for children with BSIs is associated with change in organ dysfunction as measured by PELOD-2 scores.

METHODS

We conducted a multicenter, retrospective cohort study of critically ill children <18 years old with BSIs. The primary outcome was change in PELOD-2 score between days 1 (index blood culture) and 5. The exposure variable was delayed administration of adequate antimicrobial therapy by ≥3 h from blood culture collection. We compared PELOD-2 score changes between those who received early and delayed treatment.

RESULTS

Among 202 children, the median (interquartile range) time to adequate antimicrobial therapy was 7 (0.8-20.1) hours; 124 (61%) received delayed antimicrobial therapy. Patients who received early and delayed treatment had similar baseline characteristics. There was no significant difference in PELOD-2 score changes from days 1 and 5 between groups (PELOD-2 score difference -0.07, 95% CI -0.92 to 0.79, p = 0.88).

CONCLUSIONS

We did not find an association between delayed adequate antimicrobial therapy and PELOD-2 score changes between days 1 and 5 from detection of BSI. PELOD-2 score was not sensitive for clinical effects of delayed antimicrobial treatment.

IMPACT

In critically ill children with bloodstream infections, there was no significant change in organ dysfunction as measured by PELOD-2 scores between patients who received adequate antimicrobial therapy within 3 h of their initial positive blood culture and those who started after 3 h. Higher PELOD-2 scores on day 1 were associated with larger differences in PELOD-2 scores between days 1 and 5 from index positive blood cultures. Further study is required to determine if PELOD-2 or alternative measures of organ dysfunction could be used as primary outcome measures in trials of antimicrobial interventions in pediatric critical care research.

Criterion validity of the brief test of adult cognition by telephone (BTACT) for mild traumatic brain injury

OBJECTIVES

There is a growing demand for remote assessment options for measuring cognition after mild traumatic brain injury (mTBI). The current study evaluated the criterion validity of the Brief Test of Adult Cognition by Telephone (BTACT) in distinguishing between adults with mTBI and trauma controls (TC) who sustained injuries not involving the head or neck.

METHODS

The BTACT was administered to the mTBI (n = 46) and TC (n = 35) groups at 1-2 weeks post-injury. Participants also completed the Rivermead Post Concussion Symptoms Questionnaire.

RESULTS

The BTACT global composite score did not significantly differ between the groups (t(79) = -1.04, p = 0.30); the effect size was small (d = 0.23). In receiver operating characteristic curve analyses, the BTACT demonstrated poor accuracy in differentiating between the groups (AUC = 0.567, SE = 0.065, 95% CI [0.44, 0.69]). The BTACT's ability to discriminate between mTBI and TCs did not improve after excluding mTBI participants (n = 15) who denied ongoing cognitive symptoms (AUC = 0.567, SE = 0.072, 95% CI [0.43, 0.71]).

CONCLUSIONS

The BTACT may lack sensitivity to subacute cognitive impairment attributable to mTBI (i.e., not explained by bodily pain, post-traumatic stress, and other nonspecific effects of injury).

Noninferiority Margin Size and Acceptance of Trial Results: Contingent Valuation Survey of Clinician Preferences for Noninferior Mortality

Objectives

We used modified contingent valuation methodology to determine how noninferiority margin sizes influence clinicians’ willingness to accept clinical trial results that compare mortality in critically ill children.

Methods

We surveyed pediatric infectious diseases and critical care clinicians in Canada, Australia, and New Zealand and randomized respondents to review 1 of 9 mock abstracts describing a noninferiority trial of bacteremic critically ill children assigned to 7 or 14 d of antibiotics. Each scenario showed higher mortality in the 7-d group but met noninferiority criterion. We explored how noninferiority margins and baseline mortality rates influenced respondent acceptance of results.

Results

There were 106 survey respondents: 65 (61%) critical care clinicians, 28 (26%) infectious diseases physicians, and 13 (12%) pharmacists. When noninferiority margins were 5% and 10%, 73% (24/33) and 79% (27/33) respondents would accept shorter treatment, compared with 44% (17/39) when the margin was 20% (P = 0.003). Logistic regression adjusted for baseline mortality showed 5% and 10% noninferiority margins were more likely to be associated with acceptance of shorter treatment compared with 20% margins (odds ratio [OR] 3.5, 95% confidence interval [CI]: 1.3–9.6, P = 0.013; OR 5.1, 95% CI: 1.8–14.6, P = 0.002). Baseline mortality was not a significant predictor of acceptance of shorter treatment.

Conclusions

Clinicians are more likely to accept shorter treatment when noninferiority margins are ≤10%. However, nearly half of respondents who reviewed abstracts with 20% margins were still willing to accept shorter treatment. This is a novel application of contingent valuation methodology to elicit acceptance of research results among end users of the medical literature.

Highlights

Antimicrobial treatment duration for uncomplicated bloodstream infections in critically ill children: a multicentre observational study

Background

Bloodstream infections (BSIs) cause significant morbidity and mortality in critically ill children but treatment duration is understudied. We describe the durations of antimicrobial treatment that critically ill children receive and explore factors associated with treatment duration.

Methods

We conducted a retrospective observational cohort study in six pediatric intensive care units (PICUs) across Canada. Associations between treatment duration and patient-, infection- and pathogen-related characteristics were explored using multivariable regression analyses.

Results

Among 187 critically ill children with BSIs, the median duration of antimicrobial treatment was 15 (IQR 11–25) days. Median treatment durations were longer than two weeks for all subjects with known sources of infection: catheter-related 16 (IQR 11–24), respiratory 15 (IQR 11–26), intra-abdominal 20 (IQR 14–26), skin/soft tissue 17 (IQR 15–33), urinary 17 (IQR 15–35), central nervous system 33 (IQR 15–46) and other sources 29.5 (IQR 15–55) days. When sources of infection were unclear, the median duration was 13 (IQR 10–16) days. Treatment durations varied widely within and across PICUs. In multivariable linear regression, longer treatment durations were associated with severity of illness (+ 0.4 days longer [95% confidence interval (CI), 0.1 to 0.7, p = 0.007] per unit increase in PRISM-IV) and central nervous system infection (+ 17 days [95% CI, 6.7 to 27.4], p = 0.001). Age and pathogen type were not associated with treatment duration.

Conclusions

Most critically ill children with BSIs received at least two weeks of antimicrobial treatment. Further study is needed to determine whether shorter duration therapy would be effective for selected critically ill children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03219-z.

Death and Dying in Hospitalized Pediatric Patients: A Prospective Multicenter, Multinational Study

Background: For hospitalized children admitted outside of a critical care unit, the location, mode of death, "do-not-resuscitate" order (DNR) use, and involvement of palliative care teams have not been described across high-income countries. Objective: To describe location of death, patient and terminal care plan characteristics of pediatric inpatient deaths inside and outside the pediatric intensive care unit (PICU). Design: Secondary analysis of inpatient deaths in the Evaluating Processes of Care and Outcomes of Children in Hospital (EPOCH) randomized controlled trial. Setting/Subjects: Twenty-one centers from Canada, Belgium, the United Kingdom, Ireland, Italy, the Netherlands, and New Zealand. Measurement: Descriptive statistics were used to compare patient and terminal care plan characteristics. A multivariable generalized estimating equation examined if palliative care consult during hospital admission was associated with location of death. Results: A total of 365 of 144,539 patients enrolled in EPOCH died; 219 (60%) died in PICU and 143 (40%) died on another inpatient unit. Compared with other inpatient wards, patients who died in PICU were less likely to be expected to die, have a DNR or palliative care consult. Hospital palliative care consultation was more common in older children and independently associated with a lower adjusted odds (95% confidence interval) of dying in PICU [0.59 (0.52-0.68)]. Conclusion: Most pediatric inpatient deaths occur in PICU where patients were less likely to have a DNR or palliative care consult. Palliative care consultation could be better integrated into end-of-life care for younger children and those dying in PICU.

Magnetic Resonance Imaging Findings Are Associated with Long-Term Global Neurological Function or Death after Traumatic Brain Injury in Critically Ill Children

The identification of children with traumatic brain injury (TBI) who are at risk of death or poor global neurological functional outcome remains a challenge. Magnetic resonance imaging (MRI) can detect several brain pathologies that are a result of TBI; however, the types and locations of pathology that are the most predictive remain to be determined. Forty-two critically ill children with TBI were recruited prospectively from pediatric intensive care units at five Canadian children's hospitals. Pathologies detected on subacute phase MRIs included cerebral hematoma, herniation, cerebral laceration, cerebral edema, midline shift, and the presence and location of cerebral contusion or diffuse axonal injury (DAI) in 28 regions of interest were assessed. Global functional outcome or death more than 12 months post-injury was assessed using the Pediatric Cerebral Performance Category score. Linear modeling was employed to evaluate the utility of an MRI composite score for predicting long-term global neurological function or death after injury, and nonlinear Random Forest modeling was used to identify which MRI features have the most predictive utility. A linear predictive model of favorable versus unfavorable long-term outcomes was significantly improved when an MRI composite score was added to clinical variables. Nonlinear Random Forest modeling identified five MRI variables as stable predictors of poor outcomes: presence of herniation, DAI in the parietal lobe, DAI in the subcortical white matter, DAI in the posterior corpus callosum, and cerebral contusion in the anterior temporal lobe. Clinical MRI has prognostic value to identify children with TBI at risk of long-term unfavorable outcomes.

Testing for non-inferior mortality: a systematic review of non-inferiority margin sizes and trial characteristics

OBJECTIVE

To describe the size and variability of non-inferiority margins used in non-inferiority trials of medications with primary outcomes involving mortality, and to examine the association between trial characteristics and non-inferiority margin size.

DESIGN

Systematic review.

DATA SOURCES

Medline, Medline In Process, Medline Epub Ahead of Print and Embase Classic+Embase databases from January 1989 to December 2019.

ELIGIBILITY CRITERIA

Prospective non-inferiority randomised controlled trials comparing pharmacological therapies, with primary analyses for non-inferiority and primary outcomes involving mortality alone or as part of a composite outcome. Trials had to prespecify non-inferiority margins as absolute risk differences or relative to risks of outcome and provide a baseline risk of primary outcome in the control intervention.

RESULTS

3992 records were screened, 195 articles were selected for full text review and 111 articles were included for analyses. 82% of trials were conducted in thrombosis, infectious diseases or oncology. Mortality was the sole primary outcome in 23 (21%) trials, and part of a composite primary outcome in 88 (79%) trials. The overall median non-inferiority margin was an absolute risk difference of 9% (IQR 4.2%-10%). When non-inferiority margins were expressed relative to the baseline risk of primary outcome in control groups, the median relative non-inferiority margin was 1.5 (IQR 1.3-1.7). In multivariable regression analyses examining the association between trial characteristics (medical specialty, inclusion of paediatric patients, mortality as a sole or part of a composite primary outcome, presence of industry funding) and non-inferiority margin size, only medical specialty was significantly associated with non-inferiority margin size.

CONCLUSION

Absolute and relative non-inferiority margins used in published trials comparing medications are large, allowing conclusions of non-inferiority in the context of large differences in mortality. Accepting the potential for large increases in outcomes involving mortality while declaring non-inferiority is a challenging methodological issue in the conduct of non-inferiority trials.

Efficacy of Melatonin in Children With Postconcussive Symptoms: A Randomized Clinical Trial

BACKGROUND

Approximately 25% of children with concussion have persistent postconcussive symptoms (PPCS) with resultant significant impacts on quality of life. Melatonin has significant neuroprotective properties, and promising preclinical data suggest its potential to improve outcomes after traumatic brain injury. We hypothesized that treatment with melatonin would result in a greater decrease in PPCS symptoms when compared with a placebo.

METHODS

We conducted a randomized, double-blind trial of 3 or 10 mg of melatonin compared with a placebo (NCT01874847). We included youth (ages 8-18 years) with PPCS at 4 to 6 weeks after mild traumatic brain injury. Those with significant medical or psychiatric histories or a previous concussion within the last 3 months were excluded. The primary outcome was change in the total youth self-reported Post-Concussion Symptom Inventory score measured after 28 days of treatment. Secondary outcomes included change in health-related quality of life, cognition, and sleep.

RESULTS

Ninety-nine children (mean age: 13.8 years; SD = 2.6 years; 58% girls) were randomly assigned. Symptoms improved over time with a median Post-Concussion Symptom Inventory change score of -21 (95% confidence interval [CI]: -16 to -27). There was no significant effect of melatonin when compared with a placebo in the intention-to-treat analysis (3 mg melatonin, -2 [95% CI: -13 to 6]; 10 mg melatonin, 4 [95% CI: -7 to 14]). No significant group differences in secondary outcomes were observed. Side effects were mild and similar to the placebo.

CONCLUSIONS

Children with PPCS had significant impairment in their quality of life. Seventy-eight percent demonstrated significant recovery between 1 and 3 months postinjury. This clinical trial does not support the use of melatonin for the treatment of pediatric PPCS.

Atypical Somatic Symptoms in Adults With Prolonged Recovery From Mild Traumatic Brain Injury

Somatization may contribute to persistent symptoms after mild traumatic brain injury (mTBI). In two independently-recruited study samples, we characterized the extent to which symptoms atypical of mTBI but typical for patients suffering from somatization (e.g., gastrointestinal upset, musculoskeletal, and cardiorespiratory complaints) were present in adult patients with prolonged recovery following mTBI. The first sample was cross-sectional and consisted of mTBI patients recruited from the community who reported ongoing symptoms attributable to a previous mTBI (n = 16) along with a healthy control group (n = 15). The second sample consisted of patients with mTBI prospectively recruited from a Level 1 trauma center who had either good recovery (GOSE = 8; n = 32) or poor recovery (GOSE < 8; n = 29). In all participants, we evaluated atypical somatic symptoms using the Patient Health Questionnaire-15 and typical post-concussion symptoms with the Rivermead Post-Concussion Symptom Questionnaire. Participants with poor recovery from mTBI had significantly higher "atypical" somatic symptoms as compared to the healthy control group in Sample 1 (b = 4.308, p < 0.001) and to mTBI patients with good recovery in Sample 2 (b = 3.169, p < 0.001). As would be expected, participants with poor outcome in Sample 2 had a higher burden of typical rather than atypical symptoms [t ₍₂₈₎ = 4.750, p < 0.001, d = 0.88]. However, participants with poor recovery still reported atypical somatic symptoms that were significantly higher (1.4 standard deviations, on average) than those with good recovery. Our results suggest that although "typical" post-concussion symptoms predominate after mTBI, a broad range of somatic symptoms also frequently accompanies mTBI, and that somatization may represent an important, modifiable factor in mTBI recovery.

The Canadian Traumatic Brain Injury Research Consortium: Epitomizing Collaborative Research in Canada

Traumatic brain injury (TBI) is the leading cause of death in the first half of life and a chronic disability for Canadians of all ages. Despite the recognized importance of TBI, there is no integrated national strategy for research and best practices in Canada. We therefore created the Canadian TBI Research Consortium (CTRC) to build an ideal model of collaboration between Canadian TBI researchers. Our objectives were to: (1) Create a collaborative Canadian research network, (2) improve patient survival, functional outcome, and health through sustainable and scalable evidence-based practice implementation, (3) strengthen the healthcare system for patients with TBI, (4) provide international leadership and collaboration in TBI research, (5) build stronger links with patients and their representatives to help set the research agenda, and to participate in analysis of its impacts, and (6) support current researchers and prepare the next generation of leaders in TBI research. Building on the highly successful 30-year history of the Canadian Critical Care Trials Group, we developed a highly collaborative research group that integrates the multi-disciplinary network of TBI researchers in Canada. The CTRC conducts multi-center clinically relevant practice changing research. Our research is developed around investigator-led project-based research using a programmatic approach and multiple methodologies. Through strong and sustainable career development and mentorship programs, we train and develop the next generation of TBI researchers. Our group is composed of more than 100 Canadian researchers from coast to coast, most of them funded by the Canadian Institutes of Health Research and other granting agencies. In conclusion, the CTRC prioritizes investigator-led TBI research and broadens the research agenda by integrating researchers from different disciplines in the field of TBI research to optimize delivery of care and improve the health of Canadians with TBI. Our goals are being accomplished across the whole continuum of care by conducting clinically relevant and practice-changing research.

A multiple-dose double-blind randomized study to evaluate the safety, pharmacokinetics, pharmacodynamics and analgesic efficacy of the TRPV1 antagonist JNJ-39439335 (mavatrep)

BACKGROUND AND AIMS

This double-blind (DB), randomized, placebo-controlled, sequential-group, multiple-ascending dose, phase 1 study evaluated safety, pharmacokinetics and pharmacodynamics of JNJ-39439335 in healthy men (part 1), and in participants with knee osteoarthritis (part 2).

METHODS

Both parts 1 and 2 consisted of screening (upto 21 days), 21-day DB treatment phase [eight participants/group: JNJ-39439335 (part 1: 2-50 mg; part 2: 10-50 mg): n=6; placebo: n=2] and follow-up (total study duration ~10 weeks).

RESULTS

Plasma concentrations and systemic exposure of JNJ-39439335 increased in slightly higher than dose-proportional fashion (steady-state reached by day 14). Renal excretion of JNJ-39439335 was negligible. Marked dose-related increases in pharmacodynamic heat pain assessments were observed in JNJ-39439335-treated participants, which persisted throughout the treatment with no signs of tolerance with repeated dosing. No effect on pharmacodynamic cold pain or mechanical pain assessments were seen. Effects on pharmacodynamic capsaicin-induced flare assessments in JNJ-39439335-treated participants versus placebo were consistent with effects observed with single-dose, and did not demonstrate tolerance with multiple dosing. In participants with knee osteoarthritis, significant improvements versus placebo were observed in a stair-climbing-induced pain model. All JNJ-39439335-treated participants reported ≥1 treatment-emergent adverse events (TEAE); most common (≥50% incidence) TEAEs in part 1 were feeling hot (79%), thermohypoesthesia (71%), paresthesia (58%) and feeling cold (50%), and in part 2, were minor thermal burns (50%).

CONCLUSIONS

JNJ-39439335 (doses 2-50 mg) was well-tolerated, and associated with acceptable multiple-dose pharmacokinetic profile. JNJ-39439335 demonstrated sustained pharmacodynamic effects (heat pain perception, heat pain latency, capsaicin-induced flare), and an efficacy signal in participants with osteoarthritis pain.

IMPLICATIONS

Given the efficacy signal observed and the unique safety profile, larger phase 2 studies are needed to better understand the potential of JNJ-39439335 in the treatment of chronic pain. Analgesic efficacy of lower doses administered over a longer period of time and improved patient counseling techniques to reduce the minor thermal burns can be explored to minimize the adverse events.

Effect of a Pediatric Early Warning System on All-Cause Mortality in Hospitalized Pediatric Patients: The EPOCH Randomized Clinical Trial

IMPORTANCE

There is limited evidence that the use of severity of illness scores in pediatric patients can facilitate timely admission to the intensive care unit or improve patient outcomes.

OBJECTIVE

To determine the effect of the Bedside Paediatric Early Warning System (BedsidePEWS) on all-cause hospital mortality and late admission to the intensive care unit (ICU), cardiac arrest, and ICU resource use.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter cluster randomized trial of 21 hospitals located in 7 countries (Belgium, Canada, England, Ireland, Italy, New Zealand, and the Netherlands) that provided inpatient pediatric care for infants (gestational age ≥37 weeks) to teenagers (aged ≤18 years). Participating hospitals had continuous physician staffing and subspecialized pediatric services. Patient enrollment began on February 28, 2011, and ended on June 21, 2015. Follow-up ended on July 19, 2015.

INTERVENTIONS

The BedsidePEWS intervention (10 hospitals) was compared with usual care (no severity of illness score; 11 hospitals).

MAIN OUTCOMES AND MEASURES

The primary outcome was all-cause hospital mortality. The secondary outcome was a significant clinical deterioration event, which was defined as a composite outcome reflecting late ICU admission. Regression analyses accounted for hospital-level clustering and baseline rates.

RESULTS

Among 144 539 patient discharges at 21 randomized hospitals, there were 559 443 patient-days and 144 539 patients (100%) completed the trial. All-cause hospital mortality was 1.93 per 1000 patient discharges at hospitals with BedsidePEWS and 1.56 per 1000 patient discharges at hospitals with usual care (adjusted between-group rate difference, 0.01 [95% CI, -0.80 to 0.81 per 1000 patient discharges]; adjusted odds ratio, 1.01 [95% CI, 0.61 to 1.69]; P = .96). Significant clinical deterioration events occurred during 0.50 per 1000 patient-days at hospitals with BedsidePEWS vs 0.84 per 1000 patient-days at hospitals with usual care (adjusted between-group rate difference, -0.34 [95% CI, -0.73 to 0.05 per 1000 patient-days]; adjusted rate ratio, 0.77 [95% CI, 0.61 to 0.97]; P = .03).

CONCLUSIONS AND RELEVANCE

Implementation of the Bedside Paediatric Early Warning System compared with usual care did not significantly decrease all-cause mortality among hospitalized pediatric patients. These findings do not support the use of this system to reduce mortality.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01260831.

Medical and Cognitive Outcome in Children with Traumatic Brain Injury

Background:

Head injury is an important cause of morbidity and mortality in pediatrics. Comprehensive studies on outcome are scarce despite significant clinical concern that multiple areas of functioning may be impaired following moderate to severe head injury. The literature suggests that sequelae include not only medical problems but also impairments in cognitive functioning.

Methods:

Aretrospective medical and psychology chart review of patients, age 1-18 years, admitted to the Children's Hospital of Eastern Ontario with moderate (Glasgow Coma Scale [GCS] 9-12) or severe head injury (GCS ≤ 8) from November 1, 1993 until December 31, 1998 was conducted. Correlations were performed between medical variables (i.e., GCS, Pediatric Risk of Mortality [PRISM] III score, duration of ICU and hospital stay) and measures of intelligence and memory functioning.

Results:

Eighty-three children age 1 to 18 were included. Seventy percent of the children were classified as having a severe head injury. There was a mortality rate of thirteen percent. Younger age at injury, lower GCS, and higher PRISM III scores predicted higher mortality. Medical complications were documented systematically. Forty-four patients underwent at least one cognitive assessment and 17 of these children had intelligence testing at three points in time: baseline (< four months), early recovery (five to 15 months) and follow-up (16 to 38 months). The mean intelligence and memory scores fell within the average range at the latest point in follow-up. For those children who underwent three serial assessments, the mean verbal and performance IQ fell within the low average range at baseline improving significantly to fall within the average range by early recovery. Continued improvements were apparent in verbal memory beyond early recovery, with the mean obtained at follow-up falling within 1 SD of the normative mean. Despite the return to normal ranges for the group means the proportion of scores falling below 1.5 standard deviations from the mean was greater than population norms for verbal IQ, performance IQ and verbal memory. Lower GCS scores and longer duration of stay in ICU or hospital were predictive of lower nonverbal intelligence. Lower GCS was also predictive of lower visual memory scores.

Conclusions:

This study describes a population of Canadian children who suffered moderate or severe traumatic brain injury. Initial GCS was the best predictor of mortality and cognitive outcome. These children demonstrated a temporal improvement in intelligence and memory functioning, with their mean performance on these cognitive measures falling within the average range at 16 to 38 months postinjury, although there was considerable variability in the outcomes between individuals.

Time on the scene and interventions are associated with improved survival in pediatric out-of-hospital cardiac arrest

BACKGROUND

Survival is less than 10% for pediatric patients following out-of-hospital cardiac arrest. It is not known if more time on the scene of the cardiac arrest and advanced life support interventions by emergency services personnel are associated with improved survival.

AIM

This study was performed to determine which times on the scene and which prehospital interventions were associated with improved survival.

METHODS

We studied patients aged 3 days to 19 years old with out-of-hospital cardiac arrest, using the Resuscitation Outcomes Consortium cardiac arrest database from 11 North American regions, from 2005 to 2012. We evaluated survival to hospital discharge according to on-scene times (<10, 10 to 35 and >35 min).

RESULTS

Data were available for 2244 patients (1017 infants, 594 children and 633 adolescents). Infants had the lowest rate of survival (3.7%) compared to children (9.8%) and adolescents (16.3%). Survival improved over the 7 year study period especially among adolescents. Survival was highest in the 10 to 35 min on-scene time group (10.2%) compared to the >35 min. group (6.9%) and the <10 min. group (5.3%, p=0.01). Intravenous or intra-osseous access attempts and fluid administration were associated with improved survival, whereas advanced airway attempts were not associated with survival and resuscitation drugs were associated with worse survival.

CONCLUSIONS

In this observational study, a scene time of 10 to 35 min was associated with the highest survival, especially among adolescents. Access for fluid resuscitation was associated with increased survival but advanced airway and resuscitation drugs were not.

Acute rehabilitation practices in critically ill children: a multicenter study

OBJECTIVE

To evaluate acute rehabilitation practices in pediatric critical care units across Canada.

DESIGN

Retrospective cohort study.

SETTING

Six Canadian, tertiary care pediatric critical care units.

PATIENTS/SUBJECTS

Six hundred children aged under 17 years admitted to pediatric critical care unit during a winter and summer month of 2011 with a greater than 24-hour length of stay.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome of interest was the nature and timing of pediatric critical care unit rehabilitation practices.Rehabilitation was classified according to mobility and nonmobility interventions. Predictors of mobilization and the time to mobilization were evaluated through regression and time-dependent survival analyses, respectively. The most common form of rehabilitation provided in pediatric critical care unit was physical therapy (45.5% patients) followed by occupational therapy (4.5%) and speech and language therapy (1.5%). Interventions were primarily nonmobility in nature (69.7% of sessions), most frequently in the form of chest physiotherapy (42.7% of sessions). The median time to mobilization was 2 days (interquartile range, 1-6) as compared with 1 day for nonmobility interventions (interquartile range, 1-3). Only 57 patients (9.5%) received early mobilization. Regression analyses revealed that increasing age, admission during winter, neuromuscular blockade, and sedative infusions were associated with an increased likelihood of receiving mobility therapy. Increasing age was a predictor of early mobilization, while neuromuscular blockade was associated with delayed mobilization. No significant differences in adverse events were found between nonmobility and mobility interventions.

CONCLUSIONS

Only half of the children receive rehabilitation while in the pediatric critical care unit, and when it occurs, therapy is primarily focused on respiratory function. Mobilization appears to be reserved for at-risk children who were muscle relaxed and sedated; however, its implementation in these patients is delayed. Future pediatric-specific research is essential to identify patients at risk and to understand treatment priorities and rehabilitation strategies to improve functional recovery in critically ill children.

Seizure burden is independently associated with short term outcome in critically ill children

Seizures are common among critically ill children, but their relationship to outcome remains unclear. We sought to quantify the relationship between electrographic seizure burden and short-term neurological outcome, while controlling for diagnosis and illness severity. Furthermore, we sought to determine whether there is a seizure burden threshold above which there is an increased probability of neurological decline. We prospectively evaluated all infants and children admitted to our paediatric and cardiac intensive care units who underwent clinically ordered continuous video-electroencephalography monitoring over a 3-year period. Seizure burden was quantified by calculating the maximum percentage of any hour that was occupied by electrographic seizures. Outcome measures included neurological decline, defined as a worsening Paediatric Cerebral Performance Category score between hospital admission and discharge, and in-hospital mortality. Two hundred and fifty-nine subjects were evaluated (51% male) with a median age of 2.2 years (interquartile range: 0.3 days-9.7 years). The median duration of continuous video-electroencephalography monitoring was 37 h (interquartile range: 21-56 h). Seizures occurred in 93 subjects (36%, 95% confidence interval = 30-42%), with 23 (9%, 95% confidence interval = 5-12%) experiencing status epilepticus. Neurological decline was observed in 174 subjects (67%), who had a mean maximum seizure burden of 15.7% per hour, compared to 1.8% per hour for those without neurological decline (P < 0.0001). Above a maximum seizure burden threshold of 20% per hour (12 min), both the probability and magnitude of neurological decline rose sharply (P < 0.0001) across all diagnostic categories. On multivariable analysis adjusting for diagnosis and illness severity, the odds of neurological decline increased by 1.13 (95% confidence interval = 1.05-1.21, P = 0.0016) for every 1% increase in maximum hourly seizure burden. Seizure burden was not associated with mortality (odds ratio: 1.003, 95% confidence interval: 0.99-1.02, P = 0.613). We conclude that in this cohort of critically ill children, increasing seizure burden was independently associated with a greater probability and magnitude of neurological decline. Our observation that a seizure burden of more than 12 min in a given hour was strongly associated with neurological decline suggests that early antiepileptic drug management is warranted in this population, and identifies this seizure burden threshold as a potential therapeutic target. These findings support the hypothesis that electrographic seizures independently contribute to brain injury and worsen outcome. Our results motivate and inform the design of future studies to determine whether more aggressive seizure treatment can improve outcome.

Multicentre validation of the bedside paediatric early warning system score: a severity of illness score to detect evolving critical illness in hospitalised children

Introduction

The timely provision of critical care to hospitalised patients at risk for cardiopulmonary arrest is contingent upon identification and referral by frontline providers. Current approaches require improvement. In a single-centre study, we developed the Bedside Paediatric Early Warning System (Bedside PEWS) score to identify patients at risk. The objective of this study was to validate the Bedside PEWS score in a large patient population at multiple hospitals.

Methods

We performed an international, multicentre, case-control study of children admitted to hospital inpatient units with no limitations on care. Case patients had experienced a clinical deterioration event involving either an immediate call to a resuscitation team or urgent admission to a paediatric intensive care unit. Control patients had no events. The scores ranged from 0 to 26 and were assessed in the 24 hours prior to the clinical deterioration event. Score performance was assessed using the area under the receiver operating characteristic (AUCROC) curve by comparison with the retrospective rating of nurses and the temporal progression of scores in case patients.

Results

A total of 2,074 patients were evaluated at 4 participating hospitals. The median (interquartile range) maximum Bedside PEWS scores for the 12 hours ending 1 hour before the clinical deterioration event were 8 (5 to 12) in case patients and 2 (1 to 4) in control patients (P < 0.0001). The AUCROC curve (95% confidence interval) was 0.87 (0.85 to 0.89). In case patients, mean scores were 5.3 at 20 to 24 hours and 8.4 at 0 to 4 hours before the event (P < 0.0001). The AUCROC curve (95% CI) of the retrospective nurse ratings was 0.83 (0.81 to 0.86). This was significantly lower than that of the Bedside PEWS score (P < 0.0001).

Conclusions

The Bedside PEWS score identified children at risk for cardiopulmonary arrest. Scores were elevated and continued to increase in the 24 hours before the clinical deterioration event. Prospective clinical evaluation is needed to determine whether this score will improve the quality of care and patient outcomes.

Impact of hypotension and low cerebral perfusion pressure on outcomes in children treated with hypothermia therapy following severe traumatic brain injury: a post hoc analysis of the Hypothermia Pediatric Head Injury Trial

Hypotension and low cerebral perfusion pressure are known to be associated with unfavorable outcome in children and adults with traumatic brain injury. Using the database from a previously published, randomized controlled trial of 24 h of hypothermia therapy in children with severe traumatic brain injury, we compared the number of patients with hypotension or low cerebral perfusion pressure between the hypothermia therapy and normothermia groups. We also determined the association between these physiologic insults and unfavorable outcome using regression analysis. There were more patients with episodes of hypotension or low cerebral perfusion pressure in the hypothermia therapy group than in the normothermia group. These physiologic insults were associated with unfavorable outcome in both intervention groups. Hypotension and low cerebral perfusion pressure should be anticipated and prevented in future trials of hypothermia therapy in patients with traumatic brain injury.

Association between length of storage of transfused red blood cells and multiple organ dysfunction syndrome in pediatric intensive care patients

BACKGROUND

The objective was to determine if there is an association between red blood cell (RBC) storage time and development of new or progressive multiple organ dysfunction syndrome (MODS) in critically ill children.

STUDY DESIGN AND METHODS

This was an analytic cohort analysis of patients enrolled in a randomized controlled trial, TRIPICU (Transfusion Requirements in Pediatric Intensive Care Units; ISRCTN37246456), in which stable critically ill children were randomly assigned to a restrictive or liberal strategy. Transfused patients were analyzed using three different sliding time cutoffs (7, 14, and 21 days). Storage time for multiply transfused patients was defined according to the oldest unit transfused.

RESULTS

A total of 455 patients were retained (liberal, 310; restrictive, 145). Multivariate logistic regression was performed to determine independent associations. In the restrictive group, a maximum RBC storage time of more than 21 days was independently associated with new or progressive MODS (adjusted odds ratio [OR], 3.29; 95% confidence interval [CI], 1.21-9.04). The same association was found in the liberal group for a storage time of more than 14 days (adjusted OR, 2.50; 95% CI, 1.12-5.58). When the two groups were combined in a meta-analysis, a storage time of more than 14 days was independently associated with increased MODS (adjusted OR, 2.23; 95% CI, 1.20-4.15) and more than 21 days was associated with increased Pediatric Logistic Organ Dysfunction (PELOD) scores (adjusted mean difference, 4.26; 95% CI, 1.99-6.53) and higher mortality (9.2% vs. 3.8%).

CONCLUSION

Stable critically ill children who receive RBC units with storage times longer than 2 to 3 weeks may be at greater risk of developing new or progressive MODS.

Seizure identification in the ICU using quantitative EEG displays

OBJECTIVE

To evaluate the diagnostic accuracy of 2 quantitative EEG display tools, color density spectral array (CDSA) and amplitude-integrated EEG (aEEG), for seizure identification in the intensive care unit (ICU).

METHODS

A set of 27 continuous EEG recordings performed in pediatric ICU patients was transformed into 8-channel CDSA and aEEG displays. Three neurophysiologists underwent 2 hours of training to identify seizures using these techniques. They were then individually presented with a series of CDSA and aEEG displays, blinded to the raw EEG, and asked to mark any events suspected to be seizures. Their performance was compared to seizures identified on the underlying conventional EEG.

RESULTS

The 27 EEG recordings contained 553 discrete seizures over 487 hours. The median sensitivity for seizure identification across all recordings was 83.3% using CDSA and 81.5% using aEEG. However, among individual recordings, the sensitivity ranged from 0% to 100%. Factors reducing the sensitivity included low-amplitude, short, and focal seizures. False-positive rates were generally very low, with misidentified seizures occurring once every 17-20 hours.

CONCLUSIONS

Both CDSA and aEEG demonstrate acceptable sensitivity and false-positive rates for seizure identification among critically ill children. Accuracy of these tools would likely improve during clinical use, when findings can be correlated in real-time with the underlying raw EEG. In the hands of neurophysiologists, CDSA and aEEG displays represent useful screening tools for seizures during continuous EEG monitoring in the ICU. The suitability of these tools for bedside use by ICU nurses and physicians requires further study.

Cardiac arrhythmias associated with severe traumatic brain injury and hypothermia therapy

OBJECTIVE

Severe head trauma and/or severe hypothermia (< or =32 degrees C) can cause cardiac arrhythmias. Effect of moderate hypothermia (32-33 degrees C) on cardiac arrhythmias in children after severe traumatic brain injury is not well characterized. The objective is to determine the effect of moderate and short-term (24 hrs) hypothermia therapy on the incidence and severity of cardiac arrhythmias in children with severe traumatic brain injury compared with normothermic control subject using a 24-hr Holter recording.

DESIGN

Prospective ancillary study of a multicenter randomized, controlled clinical trial.

SETTING

A Canadian university-affiliated pediatric intensive care unit in a level III trauma center. PATIENTS Patients <18 yrs with severe traumatic brain injury.

INTERVENTIONS

Holter recording during moderate hypothermia (HYPO group; esophageal temperature 32-33 degrees C) or normothermia (NORMO group; 36.5-37.5 degrees C) induced for 24 hrs started within 8 hrs after a severe traumatic brain injury.

MEASUREMENTS AND MAIN RESULTS

Sixteen patients who had a median age of 12.7 yrs (range, 7.2-17.0 yrs) were enrolled. The time from the injury to the start of the cooling process was 7.3 hrs (range, 6.6-7.8 hrs). The temperature when Holter recording began was 32.9 degrees C (range, 31.6-34.4 degrees C) in the HYPO group. Overall, 44% of all patients (seven of 16 patients) had arrhythmias (two of nine in the NORMO group and five of seven in the HYPO group, p = .13). The most frequent arrhythmias were isolated premature atrial contractions. Hypothermic patients had lower heart rates than normothermic patients (p = .01), but none had a severe bradycardia. In the NORMO group, one patient had accelerated junctional rhythm associated with hypotension. In the HYPO group, one patient had nonsustained monomorphic ventricular tachycardia.

CONCLUSIONS

Arrhythmias are frequent in severe pediatric traumatic brain injury. Further studies are needed to characterize the epidemiology and clinical impact of arrhythmias associated with severe pediatric head trauma and moderate hypothermia.

A prospective multicenter study of adrenal function in critically ill children

RATIONALE

Adrenal insufficiency is a clinical condition associated with fluid- and catecholamine-resistant hypotension.

OBJECTIVES

The objectives of this study were to determine the prevalence of adrenal insufficiency, risk factors and potential mechanisms for its development, and its association with clinically important outcomes in critically ill children.

METHODS

A prospective, cohort study was conducted from 2005 to 2008 in seven tertiary-care, pediatric intensive care units in Canada on patients up to 17 years of age with existing vascular access. Adrenocorticotropic hormone stimulation tests (1 microg) were performed and adrenocorticotropic hormone levels measured in all participants.

MEASUREMENTS AND MAIN RESULTS

A total of 381 patients had adrenal testing on admission. The prevalence of adrenal insufficiency was 30.2% (95% confidence interval, 25.9-35.1). Patients with adrenal insufficiency had higher baseline cortisol levels (28.6 microg/dl vs. 16.7 microg/dl, P < 0.001) and were significantly older (11.5 yr vs. 2.3 yr, P < 0.001) than those without adrenal insufficiency. Adrenal insufficiency was associated with an increased need for catecholamines (P < 0.001) and more fluid boluses (P = 0.026). The sensitivity and specificity of the low-dose adrenocorticotropic hormone stimulation test were 100% and 84%, respectively.

CONCLUSIONS

Adrenal insufficiency occurs in many disease conditions in critically ill children and is associated with an increased use of catecholamines and fluid boluses. It is likely multifactorial in etiology and is associated with high baseline cortisol levels. Further research is necessary to determine which of these critically ill children are truly cortisol deficient before any treatment recommendations can be made.

Vasopressin in pediatric vasodilatory shock: a multicenter randomized controlled trial

RATIONALE

Vasopressin has been proposed as a potent vasoactive agent in the treatment of vasodilatory shock in adults and children. The objective of this trial was to evaluate the efficacy and safety of vasopressin as an adjunctive agent in pediatric vasodilatory shock.

METHODS

In this multicenter, double-blind trial, children with vasodilatory shock were randomized to receive low-dose vasopressin (0.0005-0.002 U/kg/min) or placebo in addition to open-label vasoactive agents. Vasoactive infusions were titrated to clinical endpoints of adequate perfusion. The primary outcome was time to vasoactive-free hemodynamic stability. Secondary outcomes included mortality, organ-failure-free days, length of critical care unit stay, and adverse events.

MEASUREMENTS AND MAIN RESULTS

Sixty-five of 69 children (94%) who were randomized received the study drug (33 vasopressin, 32 placebo) and were included in the analysis. There was no significant difference in the primary outcome between the vasopressin and placebo groups (49.7 vs. 47.1 hours; P = 0.85). There were 10 deaths (30%) in the vasopressin group and five (15.6%) in the placebo group (relative risk, 1.94; 95% confidence interval, 0.75-5.05; P = 0.24). There were no significant differences with respect to organ failure-free days (22 vs. 25.5 days; P = 0.11), ventilator-free days (16.5 23 days; P = 0.15), length of stay (8 vs. 8.5 days; P = 0.93), or adverse event rate ratios (12.0%; 95% confidence interval, -2.6 to 26.7; P = 0.15).

CONCLUSIONS

Low-dose vasopressin did not demonstrate any beneficial effects in this pediatric trial. Although not statistically significant, there was a concerning trend toward increased mortality. Clinical trial registered with www.controlled-trials.com (ISRCTN11597444).

Hypothermia therapy after pediatric cardiac arrest

BACKGROUND

Hypothermia therapy improves mortality and functional outcome after cardiac arrest and birth asphyxia in adults and newborns. The effect of hypothermia therapy in infants and children with cardiac arrest is unknown.

METHODS AND RESULTS

A 2-year, retrospective, 5-center study was conducted, and 222 patients with cardiac arrest were identified. Seventy-nine (35.6%) of these patients met eligibility criteria for the study (age >40 weeks postconception and <18 years, cardiac arrest >3 minutes in duration, survival for > or = 12 hours after return of circulation, and no birth asphyxia). Twenty-nine (36.7%) of these 79 patients received hypothermia therapy and were cooled to 33.7+/-1.3 degrees C for 20.8+/-11.9 hours. Hypothermia therapy was associated with higher mortality (P=0.009), greater duration of cardiac arrest (P=0.005), more resuscitative interventions (P<0.001), higher postresuscitation lactate levels (P<0.001), and use of extracorporeal membrane oxygenation (P<0.001). When adjustment was made for duration of cardiac arrest, use of extracorporeal membrane oxygenation, and propensity scores by use of a logistic regression model, no statistically significant differences in mortality were found (P=0.502) between patients treated with hypothermia therapy and those treated with normothermia. Also, no differences in hypothermia-related adverse events were found between groups.

CONCLUSIONS

Hypothermia therapy was used in resuscitation scenarios that are associated with greater risk of poor outcome. In an adjusted analysis, the effectiveness of hypothermia therapy was neither supported nor refuted. A randomized controlled trial is needed to rigorously evaluate the benefits and harms of hypothermia therapy after pediatric cardiac arrest.

Fluctuations in cortical synchronization in pediatric traumatic brain injury

Traumatic brain injury (TBI) is the leading cause of death and acquired disability in the pediatric population worldwide. We hypothesized that electroencephalography (EEG) synchrony and its temporal variability, analyzed during the acute phase following TBI, would be altered from that of normal children and as such would offer insights into TBI pathophysiology. Seventeen pediatric patients with mild to severe head injury admitted to a pediatric critical care unit were recruited along with 10 age- and gender-matched controls. Patients had two electroencephalographs performed 3 days apart. Outcome was measured at 1 year post-TBI utilizing the Pediatric Cerebral Performance Category score (PCPC). Maximal synchrony between EEG channels correlated to areas of primary injury as seen on computed tomography (CT) scan. The temporal variability of phase synchronization among EEG electrodes increased as patients recovered and emerged from coma (p < 0.001). This temporal variability correlated with outcome (Pearson coefficient of 0.74) better than the worst Glasgow Coma Scale score, length of coma, or extent of injury on CT scan. This represents a novel approach in the evaluation of TBI in children.

Hypothermia therapy after traumatic brain injury in children

BACKGROUND

Hypothermia therapy improves survival and the neurologic outcome in animal models of traumatic brain injury. However, the effect of hypothermia therapy on the neurologic outcome and mortality among children who have severe traumatic brain injury is unknown.

METHODS

In a multicenter, international trial, we randomly assigned children with severe traumatic brain injury to either hypothermia therapy (32.5 degrees C for 24 hours) initiated within 8 hours after injury or to normothermia (37.0 degrees C). The primary outcome was the proportion of children who had an unfavorable outcome (i.e., severe disability, persistent vegetative state, or death), as assessed on the basis of the Pediatric Cerebral Performance Category score at 6 months.

RESULTS

A total of 225 children were randomly assigned to the hypothermia group or the normothermia group; the mean temperatures achieved in the two groups were 33.1+/-1.2 degrees C and 36.9+/-0.5 degrees C, respectively. At 6 months, 31% of the patients in the hypothermia group, as compared with 22% of the patients in the normothermia group, had an unfavorable outcome (relative risk, 1.41; 95% confidence interval [CI], 0.89 to 2.22; P=0.14). There were 23 deaths (21%) in the hypothermia group and 14 deaths (12%) in the normothermia group (relative risk, 1.40; 95% CI, 0.90 to 2.27; P=0.06). There was more hypotension (P=0.047) and more vasoactive agents were administered (P<0.001) in the hypothermia group during the rewarming period than in the normothermia group. Lengths of stay in the intensive care unit and in the hospital and other adverse events were similar in the two groups.

CONCLUSIONS

In children with severe traumatic brain injury, hypothermia therapy that is initiated within 8 hours after injury and continued for 24 hours does not improve the neurologic outcome and may increase mortality. (Current Controlled Trials number, ISRCTN77393684 [controlled-trials.com].).

Hypothermia therapy for cardiac arrest in pediatric patients

Cardiac arrest is associated with high morbidity and mortality in children. Hypothermia therapy has theoretical benefits on brain preservation and has the potential to decrease morbidity and mortality in children following cardiac arrest. The American Heart Association guidelines recommend that it should be considered in children after cardiac arrest. Methods of inducing hypothermia include simple surface cooling techniques, intravenous boluses of cold saline, gastric lavage with ice-cold normal saline, and using the temperature control device with extracorporeal life support. We recommend further study before a strong recommendation can be made to use hypothermia therapy in children with cardiac arrest.

Severe hemodilutional anemia increases cerebral tissue injury following acute neurotrauma

Anemia may worsen neurological outcomes following traumatic brain injury (TBI) by undefined mechanisms. We hypothesized that hemodilutional anemia accentuates hypoxic cerebral injury following TBI. Anesthetized rats underwent unilateral TBI or sham injury (n > or = 7). Target hemoglobin concentrations between 50 and 70 g/l were achieved by exchanging 40-50% of the blood volume (1:1) with pentastarch. The effect of TBI, anemia, and TBI-anemia was assessed by measuring brain tissue oxygen tension (Pbr(O(2))), regional cerebral blood flow (rCBF), jugular venous oxygen saturation (Sjv(O(2))), cerebral contusion area, and nuclear staining for programmed cell death. Baseline postinjury Pbr(O(2)) values in the TBI and TBI-anemia groups (9.3 +/- 1.3 and 11.3 +/- 4.1 Torr, respectively) were lower than the uninjured controls (18.2 +/- 5.2 Torr, P < 0.05 for both). Hemodilution caused a further reduction in Pbr(O(2)) in the TBI-anemia group relative to the TBI group without anemia (7.8 +/- 2.7 vs. 14.8 +/- 3.9 Torr, P < 0.05). The rCBF remained stable after TBI and increased comparably after hemodilution in both anemia and TBI-anemia groups. The Sjv(O(2)) was elevated after TBI (87.4 +/- 8.9%, P < 0.05) and increased further following hemodilution (95.0 +/- 1.6%, P < 0.05). Cerebral contusion area and nuclear counts for programmed cell death were increased following TBI-anemia (4.1 +/- 3.0 mm(2) and 686 +/- 192, respectively) relative to TBI alone (1.3 +/- 0.3 mm(2) and 404 +/- 133, respectively, P < 0.05 for both). Hemodilutional anemia reduced cerebral Pbr(O(2)) and oxygen extraction and increased cell death following TBI. These results support our hypothesis that acute anemia accentuated hypoxic cerebral injury after neurotrauma.

Transfusion strategies for patients in pediatric intensive care units

BACKGROUND

The optimal hemoglobin threshold for erythrocyte transfusions in critically ill children is unknown. We hypothesized that a restrictive transfusion strategy of using packed red cells that were leukocyte-reduced before storage would be as safe as a liberal transfusion strategy, as judged by the outcome of multiple-organ dysfunction.

METHODS

In this noninferiority trial, we enrolled 637 stable, critically ill children who had hemoglobin concentrations below 9.5 g per deciliter within 7 days after admission to an intensive care unit. We randomly assigned 320 patients to a hemoglobin threshold of 7 g per deciliter for red-cell transfusion (restrictive-strategy group) and 317 patients to a threshold of 9.5 g per deciliter (liberal-strategy group).

RESULTS

Hemoglobin concentrations were maintained at a mean (+/-SD) level that was 2.1+/-0.2 g per deciliter lower in the restrictive-strategy group than in the liberal-strategy group (lowest average levels, 8.7+/-0.4 and 10.8+/-0.5 g per deciliter, respectively; P<0.001). Patients in the restrictive-strategy group received 44% fewer transfusions; 174 patients (54%) in that group did not receive any transfusions, as compared with 7 patients (2%) in the liberal-strategy group (P<0.001). New or progressive multiple-organ dysfunction syndrome (the primary outcome) developed in 38 patients in the restrictive-strategy group, as compared with 39 in the liberal-strategy group (12% in both groups) (absolute risk reduction with the restrictive strategy, 0.4%; 95% confidence interval, -4.6 to 5.4). There were 14 deaths in each group within 28 days after randomization. No significant differences were found in other outcomes, including adverse events.

CONCLUSIONS

In stable, critically ill children a hemoglobin threshold of 7 g per deciliter for red-cell transfusion can decrease transfusion requirements without increasing adverse outcomes. (Controlled-trials.com number, ISRCTN37246456 [controlled-trials.com].).

Biomarkers and diagnosis; protein biomarkers in serum of pediatric patients with severe traumatic brain injury identified by ICAT-LC-MS/MS

This report is a feasibility study on the utility of gel-free proteomics in identifying peripheral biomarkers of brain injury. The study was performed in six pediatric patients admitted to the intensive care unit for severe traumatic brain injury (TBI). Serum samples collected at admission (less than 8 h after injury) were used for determining the levels of S100beta by enzyme-linked immunosorbent assay (ELISA) and for proteomics analyses. Serum samples were depleted of high abundant albumin and immunoglobulin, and were compared to a pooled reference from several healthy individuals. After labeling and separation on an ionic column, six different serum fractions were analyzed using Isotope-Coded Affinity Tag (ICAT), followed by tandem mass spectrometry (MS/MS) protein sequencing and identification. Ninety-five unique, differentially expressed proteins were identified, including several with a likely brain origin. Several proteins with pattern similarity to S100beta identified by hierarchical clustering could be considered for evaluation in a larger patient sample as potential peripheral markers of TBI.

Hypoxia Alters The Expression of Inhibitor of Apoptosis Proteins after Brain Trauma in The Mouse

Hypoxia worsens brain injury following trauma, but the mechanisms remain unclear. The purpose of this study was to determine the effect of traumatic brain injury (TBI) and secondary hypoxia (9% oxygen) on apoptosis-related protein expression, cell death, and behavior. Using a murine weight-drop model, TBI led to an early (6 h) increase followed by a later (24 h) decrease in neuronal apoptosis inhibitor protein (NAIP) expression in the olfactory and motor cortex; in contrast, TBI led to a sustained (6 h to 7 days) increase in NAIP in the striatum. The peak increase in the expression of NAIP (6-12 h) following TBI alone was delayed (1-7 days) when hypoxia was added to TBI. Hypoxia following TBI further depleted other apoptosis inhibitor proteins (IAPs) and activated caspases, as well as increased contusion size and worsened cell death. Hypoxia added to TBI also increased motor and feeding activity on days 2 and 4 compared to TBI alone. Hypoxia without TBI had no effect on the expression of IAPs or cell death. These findings show that IAPs have a potential role in the increased vulnerability of brain cells to hypoxia following TBI, and have implications for configuring future therapies for TBI.

Effect of a liberal versus restrictive transfusion strategy on mortality in patients with moderate to severe head injury

OBJECTIVE

To compare a restrictive versus a liberal transfusion strategy in patients with moderate to severe closed head injury following multiple trauma in 13 Canadian intensive care units (ICUs).

METHODS

This is a subgroup analysis of a multicenter randomized controlled clinical trial involving sixty-seven critically ill patients from the Transfusion Requirements in the Critical Care trial who sustained a closed head injury. Patients had a hemoglobin concentration less than 9.0 g/dL within 72 hours of admission to the ICU. Patients were randomized to a restrictive allogeneic red blood cell transfusion strategy (hemoglobin 7.0 g/dL and maintained between 7.0 and 9.0 g/dL) or a liberal strategy (hemoglobin 10.0 g/dL and maintained between 10.0 and 12.0 g/dL).

RESULTS

Baseline characteristics in the restrictive ( n = 29) and the liberal ( n = 38) transfusion groups were comparable. Average hemoglobin concentrations and red blood cell units transfused per patient were significantly lower in the restrictive compared to the liberal group. The 30-day all-cause mortality rates in the restrictive group were 17% as compared to 13% in the liberal group (risk difference 4.1 with 95% confidence interval [CI], 13.4 to 21.5, p = 0.64). Presence of multiple organ dysfunction (12.1 +/- 6.4 versus 10.6 +/- 6.3, p = 0.35) and changes in multiple organ dysfunction from baseline scores adjusted for death (4.5 +/- 6.2 versus 3.4 +/- 6.2, p = 0.49) were similar between the restrictive and liberal transfusion groups, respectively. Median length of stay in ICU (10 days, interquartile range 5 to 21 days versus 8 days, interquartile range 5 to 11 days, p = 0.26) and hospital (27 days, interquartile range 14 to 39 days versus 30.5 days, interquartile range 17 to 47 days, p = 0.72) were similar between the restrictive and liberal transfusion groups.

CONCLUSIONS

We were unable to detect significant improvements in mortality with a liberal as compared to restrictive transfusion strategy in critically ill trauma victims with moderate to severe head injury.

Cerebrovascular disorders

Arterial ischemic stroke is being recognized more commonly in the pediatric population. The etiologies differ greatly from those seen in adults. The most common etiologies are congenital heart disease and sickle cell disease. Children may present with or without hemiparesis and may have fever, headache, and depressed level of consciousness. A high index of suspicion is needed to diagnose stroke. Although clinical studies are scarce in children, besides early diagnosis, early specialized care with careful attention to detail ensuring adequate oxygenation and ventilation, prevention of hyperthermia and seizures, and maintenance of blood pressure and metabolic balance are important and likely improve outcome in these children. Selective children may also benefit from anticoagulant therapy, and, as the interval to diagnosis decreases, thrombolytic therapy may become an option although safety data are required. Children with acute stroke should be rapidly transported to and cared for in a pediatric center with a specialized stroke team or access to acute stroke protocols.

Prolonged therapeutic hypothermia after traumatic brain injury in adults: a systematic review

CONTEXT

The benefits of therapeutic hypothermia as a treatment for traumatic brain injury (TBI) remain unclear.

OBJECTIVE

To explore the effects of depth, duration, and rate of rewarming after discontinuation of hypothermia on mortality and neurologic outcome in adults after TBI.

DATA SOURCES

An electronic search of MEDLINE (OVID), EMBASE, Current Contents, the Cochrane library and a hand search of key journals were performed. Corresponding authors of identified studies were contacted for additional unpublished or ongoing clinical trials.

STUDY SELECTION

All randomized controlled trials of therapeutic hypothermia for at least 24 hours vs normothermia in adults with TBI.

DATA EXTRACTION

Demographic and clinical data, hypothermia interventions and cointerventions, mortality and neurologic outcomes, and methodological quality were abstracted by 2 independent reviewers.

DATA SYNTHESIS

Twelve trials met eligibility criteria and were included in the analysis. We also performed subanalyses by different hypothermia interventions (ie, depth, duration, and rapidity of rewarming after hypothermia) and methodological quality. Therapeutic hypothermia was associated with a 19% reduction in the risk of death (95% confidence interval [CI], 0.69-0.96) and a 22% reduction in the risk of poor neurologic outcome (95% CI, 0.63-0.98) compared with normothermia. Hypothermia longer than 48 hours was associated with a reduction in the risks of death and of poor neurologic outcome (relative risk [RR], 0.70; 95% CI, 0.56-0.87 and RR, 0.65; 95% CI, 0.48-0.89, respectively) compared with normothermia. Hypothermia to a target temperature between 32 degrees C and 33 degrees C, a duration of 24 hours, and rewarming within 24 hours were all associated with reduced risks of poor neurologic outcome compared with normothermia. Assessment of methodological quality did not reveal evidence of bias.

CONCLUSIONS

Therapeutic hypothermia may reduce the risks of mortality and poor neurologic outcome in adults with TBI. Outcomes were influenced, however, by depth and duration of hypothermia as well as rate of rewarming (<or=24 hours) after discontinuation of hypothermia. Nonetheless, the evidence is not yet sufficient to recommend routine use of therapeutic hypothermia for TBI outside of research settings.

Neuronal apoptosis inhibitory protein expression after traumatic brain injury in the mouse

Apoptosis of brain cells is triggered by traumatic brain injury (TBI) and is blocked by caspase inhibitors. The neuronal apoptosis inhibitor protein (NAIP), which has been shown to inhibit apoptosis by both caspase-dependant and caspase-independent mechanisms, is neuroprotective in rat models of cerebral ischemia and axotomy. In order to gain a better appreciation of CNS apoptosis following head injury in general and the possible involvement of NAIP specifically, we have configured a mouse model of TBI. In addition to demonstrating apoptosis, the spatiotemporal expression or levels of a number of proteins with apoptosis modulating effects have been determined. Apoptosis of neurons and oligodendrocytes following TBI was observed in brain sections which were triple-stained with in situ end labeling, bisbenzimide and immunofluorescent stain for neuron specific nuclear protein and myelin-associated glycoprotein, respectively. Further evidence for apoptosis following TBI in this model was obtained in brain samples using ligation-mediated PCR amplification of DNA fragments and gel electrophoresis. The temporal profile of apoptosis was similar to the temporal profile of microglial activation determined by CD11b staining and TNFa expression induced by TBI. NAIP staining in sections of cerebral cortex and subcortical white matter increased at 6 h and decreased towards control levels at 24 h post-TBI. Temporal changes in the expression of NAIP were also observed using Western blot analysis of brain samples removed from injured cortex and sub-cortical white matter. At the time that NAIP expression decreased markedly (24 h post-TBI), procaspase-3 levels also decreased, PARP cleavage increased, and the highest levels of apoptosis were observed. These findings have implications in our understanding of traumatically induced programmed cell death and may be useful in the configuration of therapies for this common injury state.

Effects of moderate hypothermia on IL-1 beta-induced leukocyte rolling and adhesion in pial microcirculation of mice and on proinflammatory gene expression in human cerebral endothelial cells

Although the neuroprotective effects of hypothermia have been known for a long time, the molecular correlates of this neuroprotection are poorly understood. In this study, the authors investigated how hypothermia affects inflammatory responses in the brain elicited by systemic injection of IL-1 beta. Leukocyte rolling and adhesion were quantified in pial venules (20 to 50 microm) of C57/Bl6 mice 4 hours after intraperitoneal injection of IL-1 beta (5 microg/kg) using an open cranial window and intravital microscopy. Animals were subjected to moderate hypothermia (32 degrees C) or normothermia (37 degrees C) for 1 or 4 hours after IL-1 beta injection. Significant increases in leukocyte rolling and adhesion were observed in IL-1 beta-injected animals as compared with sham controls. Whereas 1-hour hypothermia did not affect IL-1 beta-induced leukocyte rolling and adhesion, 4-hour hypothermia caused a reduction in both rolling and adhesion. Molecular mechanisms of hypothermic effects were investigated in cultured human cerebral endothelial cells exposed to IL-1 beta (50 U/mL) for 4 hours at 37 degrees C or 32 degrees C followed by 18 hours at 37 degrees C. Human cerebral endothelial cells exposed to IL-1 beta at 32 degrees C showed attenuated NF-kappa B activation determined by the Luciferase yellow reporter gene assay and reduced expression of IL-8 and IL-1 beta measured by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay. Intracellular adhesion molecule-1 was induced to similar levels (threefold over control) at both temperatures. The expression of CD18 on neutrophils in vitro was not affected by either IL-1 beta or hypothermia. These findings suggest that mechanisms by which hypothermia reduces leukocyte rolling and adhesion include suppression of inflammatory gene transcription in brain endothelial cells.

Inhaled nitric oxide protects against hyperoxia-induced apoptosis in rat lungs

Inhaled nitric oxide (NO), frequently administered in combination with hyperoxic gas mixtures, was recently shown to protect against the injurious consequences of prolonged hyperoxia. We investigated the possibility that this protective effect is attributable to the ability of NO to block pulmonary apoptosis. We show that rats exposed to 100% O2 for 60 h develop severe lung injury consisting of pronounced vascular leak and alveolar apoptosis as inferred from the presence of positive terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling and DNA ladders in agarose gels and a decrease in constitutive procaspase-3 levels. However, the inclusion of NO (20 parts/million) in the hyperoxic gas mixture significantly attenuated both the vascular leak and apoptosis. NO reversed the hyperoxia-associated changes in the activity of the redox-sensitive transcription factors nuclear factor-kappaB, activator protein-1, and Sp1 after 24 h, lowered intercellular adhesion molecule-1 levels, and increased glutathione content. We therefore show, for the first time, that NO can protect against both hyperoxia-induced apoptosis and inflammation. The data suggest that this protection may occur at the transcriptional and caspase-activation levels.

A mouse monoclonal antibody to a thyrotropin receptor ectodomain variant provides insight into the exquisite antigenic conformational requirement, epitopes and in vivo concentration of human autoantibodies

We used the secreted TSH receptor (TSHR) ectodomain variant TSHR-289 (truncated at amino acid residue 289 with a 6-histidine tail) to investigate properties of TSHR autoantibodies in Graves' disease. Sequential concanavalin A and Ni-chelate chromatography extracted milligram quantities of TSHR-289 (approximately 20-40% purity) from the culture medium. Nanogram quantities of this material neutralized the TSH binding inhibitory activity in all 15 Graves' sera studied. We generated a mouse monoclonal antibody (mAb), 3BD10, to partially purified TSHR-289. Screening of a TSHR complementary DNA fragment expression library localized the 3BD10 epitope to 27 amino acids at the N-terminus of the TSHR, a cysteine-rich segment predicted to be highly conformational. 3BD10 preferentially recognized native, as opposed to reduced and denatured, TSHR-289, but did not interact with the TSH holoreceptor on the cell surface. Moreover, mAb 3BD10 could extract from culture medium TSHR-289 nonreactive with autoantibodies, but not the lesser amount (approximately 25%) of TSHR-289 molecules capable of neutralizing autoantibodies. Although the active form of TSHR-289 in culture medium was stable at ambient temperature, stability was reduced at 37 C, explaining the mixture of active and inactive molecules in medium harvested from cell cultures. In conclusion, studies involving a TSHR ectodomain variant indicate the exquisite conformational requirements of TSHR autoantibodies. Even under "native" conditions, only a minority of molecules in highly potent TSHR-289 preparations neutralize patients' autoantibodies. Therefore, Graves' disease is likely to be caused by even lower concentrations of autoantibodies than previously thought. Finally, reciprocally exclusive binding to TSHR-289 by human autoantibodies and a mouse mAb with a defined epitope suggests that the extreme N-terminus of the TSHR is important for autoantibody recognition.

A bolus of recombinant human follicle stimulating hormone at midcycle induces periovulatory events following multiple follicular development in macaques

The efficacy of follicle stimulating hormone (FSH) as an alternative to luteinizing hormone (LH)/human chorionic gonadotrophin (HCG) for the initiation of periovulatory events in primate follicles is unknown. A single bolus of 2500 IU recombinant (r)-hFSH was compared to 1000 IU r-HCG for its ability to promote oocyte nuclear maturation and fertilization, granulosa cell luteinization and corpus luteum function following r-hFSH (60 IU/day) induction of multiple follicular development in rhesus monkeys. Following the r-hFSH bolus, bioactive luteinizing hormone concentrations were <3 ng/ml. Peak concentrations of serum FSH (1455+/-314 mIU/ml; mean+/-SEM) were attained 2-8 h after r-hFSH, and declined by 96 h. Bioactive HCG concentrations peaked between 2-8 h after r-HCG and remained > or = 100 ng/ml for >48 h, while immunoreactive FSH concentrations were at baseline. The proportion of oocytes resuming meiosis and undergoing in-vitro fertilization (IVF) were comparable for r-hFSH (89%; 47+/-19%) and r-HCG (88%; 50+/-17%). In-vitro progesterone production and expression of progesterone receptors in granulosa cells did not differ between groups. Peak concentrations of serum progesterone in the luteal phase were similar, but were lower 6-9 days post-FSH relative to HCG. Thus, a bolus of r-hFSH was equivalent to r-HCG for the reinitiation of oocyte meiosis, fertilization and granulosa cell luteinization, but a midcycle FSH surge did not sustain normal luteal function in primates.

Surfactant therapy improves pulmonary function in infants with Pneumocystis carinii pneumonia and acquired immunodeficiency syndrome

Pneumocystis carinii pneumonia (PCP) is an important cause of acute respiratory failure in HIV-infected children. PCP may initiate acute respiratory distress syndrome (ARDS) by adversely affecting surfactant physiology. We report improved pulmonary function following administration of bovine lipid extract surfactant to two infants with AIDS-related PCP/ARDS.

Initiation of periovulatory events in gonadotrophin-stimulated macaques with varying doses of recombinant human chorionic gonadotrophin

During in-vitro fertilization (IVF) cycles, a large bolus of human chorionic gonadotrophin (HCG) is used to induce periovulatory events, but the efficacy of lower doses is undefined. Following follicular stimulation in rhesus monkeys, oocyte nuclear maturation, IVF, granulosa cell luteinization and corpus luteum function were compared after injection of 100, 300 or 1000 IU recombinant HCG or 1000 IU urinary HCG. Bioactive HCG rose to peak concentrations within 2 h that were proportional to the dose administered (100 < 300 < 1000 IU, recombinant HCG = urinary HCG). The duration of surge values (>100 ng/ml) was also dose-dependent (0 h, 100 IU; 24 h, 300 IU; >48 h, 1000 IU, recombinant and urinary HCG). While the proportions of oocytes resuming meiosis and undergoing IVF were similar among groups, fewer animals yielded fertilizable oocytes following 100 and 300 IU (five of nine) compared to 1000 IU recombinant and urinary HCG (nine of 10). Peak values of serum progesterone in the luteal phase were similar, but declined 2 days earlier after 100 and 300 IU relative to 1000 IU recombinant and urinary HCG. Thus, 3-10 fold lower doses of HCG elicit low amplitude surges of short duration that induce periovulatory events such as re-initiation of oocyte meiosis and granulosa cell luteinization. However, oocyte fertilization and luteal function may optimally require surges of higher amplitude and longer duration similar to those produced by standard doses of 1000 IU recombinant or urinary HCG.

Stimulation of primate luteal function by recombinant human chorionic gonadotropin and modulation of steroid, but not relaxin, production by an inhibitor of 3 beta-hydroxysteroid dehydrogenase during simulated early pregnancy

CG produced by fetal tissues extends the functional lifespan of the primate corpus luteum during early pregnancy. Previous studies showed that urinary hCG administered to monkeys to simulate the rising CG levels associated with early pregnancy enhanced both progesterone (P) and relaxin (RLX) production by the corpus luteum. The current study was designed: 1) to compare the ability of recombinant (r) and urinary (u) hCG to stimulate luteal function, and 2) to assess the role of P in the regulation of luteal RLX secretion during simulated early pregnancy by concomitant administration of hCG and the 3 beta-hydroxysteroid dehydrogenase inhibitor trilostane to reduce P production. Rhesus monkeys received injections of either r-hCG or u-hCG (Ares Serono) in increasing doses (15-2880 IU/dose, twice daily) for 9 days beginning on day 9 of the luteal phase (n = 5/group). An additional group (n = 4) received r-hCG as described above, with concomitant oral administration of trilostane (500 mg/dose twice daily; Sanofi Winthrop). Daily serum samples were assayed for hCG by immunoradiometric assay, steroid hormones by RIA, and RLX by enzyme-linked immunosorbent assay. Serum hCG levels typically were not different between the r-HCG and u-hCG groups during or after treatment. Concentrations of hCG peaked 1 day after the final injection in monkeys receiving r-hCG (mean +/- SEM. 2759 +/- 120 mIU/mL) and u-hCG (2120 +/- 60 mIU/mL) and dropped below 5 mIU/mL by 10 days after the final treatment in all groups. Both r-hCG and u-hCG stimulated luteal P and RLX production. Progesterone levels rose rapidly after the initiation of hCG treatment and peaked in animals receiving r-hCG (14.4 +/- 2.8 ng/mL) and u-hCG (11.9 +/- 1.4 ng/mL) 4 days after initial administration. RLX levels peaked in the r-hCG (400 +/- pg/mL) and u-hCG (323 +/- 85 pg/mL) groups within 4 days of the final hCG treatment. Trilostane with r-hCG reduced P concentrations to very low levels (< 0.5 ng/mL; P < 0.01) within 1 day of administration compared to those in animals receiving r-hCG only and maintained these low levels for the entire treatment interval. Nevertheless, trilostane administration did not alter luteal RLX production, with serum levels peaking at 377 +/- 76 pg/mL. These data indicate that r-hCG and u-hCG were equally efficacious in stimulating the steroidogenic and peptidergic activities of the corpus luteum during simulated early pregnancy. In addition, P deprivation during r-hCG administration did not alter circulating RLX levels, suggesting that P is not a major regulator of RLX production by the primate corpus luteum during early pregnancy.

Developmental potential of embryos produced by in-vitro fertilization from gonadotrophin-releasing hormone antagonist-treated macaques stimulated with recombinant human follicle stimulating hormone alone or in combination with luteinizing hormone

We previously demonstrated, in luteinizing hormone (LH)-deficient macaques, that follicular growth and maturation occurred with administration of exogenous (recombinant human) follicle stimulating hormone (r-hFSH) alone, and that the oocytes recovered fertilized at a notably higher rate than their counterparts from animals receiving both r-hFSH and r-hLH (Zelinski-Wooten et al., 1995). Here, the developmental potential of embryos produced from animals treated with r-hFSH alone or in combination with r-hLH was evaluated. Embryos (n = 127) were cryopreserved, thawed and either co-cultured on buffalo rat liver cells until the hatched blastocyst stage or transferred to synchronized recipients. Although embryos from each treatment group demonstrated a similar ability to develop to hatched blastocysts with a definitive inner cell mass, a significant difference was seen in cryosurvival (56 versus 78%) and in developmental rate to the hatched blastocyst (12 versus 10 days) between embryos from the r-hFSH alone and the combination group respectively. Pregnancies resulted following oviductal embryo transfers in both groups, with corpus luteum rescue occurring on days 12-16 of the luteal phase. In summary, r-hFSH alone during the pre-ovulatory interval is adequate for the gametogenic events required to produce embryos that develop either in vitro or in vivo; however, exposure to r-hLH may improve embryo viability and the rate of development.

Follicle stimulating hormone alone supports follicle growth and oocyte development in gonadotrophin-releasing hormone antagonist-treated monkeys

Both follicle stimulating hormone (FSH) and luteinizing hormone (LH) are proposed requirements for follicular growth and steroidogenesis; however, the role of LH in primate folliculogenesis is unclear. Follicular stimulation by recombinant human FSH (n = 5) with and without recombinant LH (1:1; n = 6) following 90 days of gonadotrophin-releasing hormone (GnRH) antagonist (Antide) treatment in macaques was evaluated. Human chorionic gonadotrophin (HCG) was administered when six follicles > or = 4 mm were observed. Oocytes were aspirated 27 h later and inseminated in vitro. Chronic Antide reduced serum oestradiol and bioactive LH to concentrations observed in hypophysectomized rhesus monkeys. Multiple follicular growth required a longer interval following recombinant FSH (12 +/- 1 days) than recombinant FSH+recombinant LH (9 +/- 0.2 days), but the total number of follicles/animal did not differ between groups. The day prior to HCG, oestradiol concentrations were 4-fold less following recombinant FSH compared to recombinant FSH+recombinant LH. With recombinant FSH, more oocytes completed meiosis to metaphase II (51%) and fertilized (89 +/- 5%) relative to recombinant FSH+recombinant LH (12 and 52 +/- 11% respectively). Follicular growth and maturation in LH-deficient macaques occurred with FSH alone. Thus, LH is not required for folliculogenesis in primates. Higher fertilization rates following follicular stimulation with FSH alone suggest that the presence of LH with FSH (1:1) during the pre-ovulatory interval impairs gametogenic events in the periovulatory period.

Glycosylated recombinant human tumor necrosis factor binding protein-1 reduces mortality, shock, and production of tumor necrosis factor in rabbit Escherichia coli sepsis

OBJECTIVE

To examine the effect of glycosylated recombinant human tumor necrosis factor binding protein-1 (r-hTNF binding protein-1), the extracellular domain of the tumor necrosis factor receptor p55 produced in mammalian cells, in a rabbit model of circulatory shock due to Escherichia coli.

DESIGN

Prospective, randomized, controlled trial.

SETTING

University hospital research laboratory.

SUBJECTS

Eighteen female, New Zealand white rabbits.

INTERVENTIONS

Anesthetized rabbits, infused with E. coli (10(9) organisms/kg), were pretreated with either r-hTNF binding protein-1 or saline. Mean arterial pressure, central venous pressure, cardiac output, and heart rate were recorded every 20 mins for 1 hr before, and for 4 hrs after, the infusion of E. coli. Blood samples were obtained at 1-hr intervals for platelet count and white blood cell count, r-hTNF binding protein-1, and tumor necrosis factor (TNF) measurements.

MEASUREMENTS AND MAIN RESULTS

Administration of r-hTNF binding protein-1 resulted in improvement of mean arterial pressure, cardiac output, and systemic vascular resistance, as compared with the vehicle-treated group (p < .05). Treatment with r-hTNF binding protein-1 was associated with 100% survival, as compared with 55.6% of the saline-treated rabbits (p < .05). Approximately 85% of r-hTNF binding protein-1 was cleared from the circulation 1 hr after the bolus injection (from 171 +/- 27 micrograms/mL at time = 0, to 27 +/- 4 micrograms/mL at 60 mins, decreasing to 6 +/- 2 micrograms/mL for the next 3 hrs). The r-hTNF binding protein-1-treated rabbits had lower serum TNF bioactivity during the first 2 hrs (p < .01). The decreased bioactivity of TNF was confirmed by a specific radioimmunoassay for rabbit TNF. However, at 4 hrs, the vehicle-treated rabbits had lower serum bioactive TNF concentrations (p < .05). The decrease in TNF concentrations in the r-hTNF binding protein-1-treated rabbits resulted from decreased production and, in part, from carry-over of r-hTNF binding protein-1 into the bioassay.

CONCLUSIONS

Treatment with r-hTNF binding protein-1 improved hemodynamic variables and survival of E. coli-challenged rabbits. Administration of r-hTNF binding protein-1 suppressed bioactivity of TNF in the circulation of these rabbits, and the production of TNF as well.

Initiation of periovulatory events in primate follicles using recombinant and native human luteinizing hormone to mimic the midcycle gonadotropin surge

The amplitude and duration of the midcycle LH surge required for periovulatory changes in the primate follicle are incompletely defined. We reported that short (4- to 14-h) LH surges were insufficient to induce periovulatory events after multiple follicular development in macaques. In contrast, an 18- to 24-h LH surge induced oocyte maturation plus granulosa cell luteinization, but did not support corpus luteum function. In this study, the periovulatory changes following LH surges of 48 h elicited using pituitary (pit) or recombinant (r) human (h) LH were compared to those after 24-h LH surge durations or after urinary hCG (u-hCG) treatment. Beginning at menses, rhesus monkeys were treated with human gonadotropins for 9 days to stimulate follicular growth. On day 10, animals (n = 3-5/group) received 1) a single injection of u-hCG [79 +/- 3 micrograms RP-1 equivalents (equiv), im], 2) two injections of pit-hLH (91 +/- 4 micrograms RP-1 equiv, im), 3) one injection of r-hLH (21 +/- 1 micrograms RP-1 equiv, im), or 4) two injections of r-hLH (21 +/- 1 micrograms RP-1 equiv). Oocytes and granulosa cells were obtained via follicle aspiration 27 h after the initial LH or hCG injection. In all groups, serum estradiol rose to similar peak levels by day 10. Circulating LH-like bioactivity was elevated for more than 48 h after u-hCG. Peak serum LH bioactivities were proportional to the administered LH doses, as determined in the in vitro bioassay. Two injections of either r-hLH or pit-hLH elicited surge levels (> 100 ng/mL) of bioactive LH for 36-48 h, whereas one injection sustained surge levels for only 18-24 h. The proportions of oocytes resuming meiosis (68-76%) were similar in all groups. Immunocytochemical staining for progesterone receptor and in vitro progesterone production by granulosa cells in all LH-treated groups were comparable to those of cells form the hCG-treated group. Peak levels of progesterone in the luteal phase were comparable in monkeys treated with two doses of pit-hLH and r-hLH (18.5 +/- 10.4 vs. 8.1 +/- 1.5 ng/mL) and approached that in u-hCG treated monkeys (39.5 +/- 18.0 ng/mL). However, progesterone levels in animals treated once with r-hLH (3.4 +/- 1.5 ng/mL) were less (P < 0.05) than those in u-hCG-treated monkeys.(ABSTRACT TRUNCATED AT 400 WORDS)