Metabotropic Glutamate Receptor 2 Expression Is Chronically Elevated in Male Rats With Post-Traumatic Stress Disorder Related Behavioral Traits Following Repetitive Low-Level Blast Exposure

Many military veterans who experienced blast-related traumatic brain injuries in the conflicts in Iraq and Afghanistan currently suffer from chronic cognitive and mental health problems that include depression and post-traumatic stress disorder (PTSD). Male rats exposed to repetitive low-level blast develop cognitive and PTSD-related behavioral traits that are present for more than 1 year after exposure. We previously reported that a group II metabotropic receptor (mGluR2/3) antagonist reversed blast-induced behavioral traits. In this report, we explored mGluR2/3 expression following blast exposure in male rats. Western blotting revealed that mGluR2 protein (but not mGluR3) was increased in all brain regions studied (anterior cortex, hippocampus, and amygdala) at 43 or 52 weeks after blast exposure but not at 2 weeks or 6 weeks. mGluR2 RNA was elevated at 52 weeks while mGluR3 was not. Immunohistochemical staining revealed no changes in the principally presynaptic localization of mGluR2 by blast exposure. Administering the mGluR2/3 antagonist LY341495 after behavioral traits had emerged rapidly reversed blast-induced effects on novel object recognition and cued fear responses 10 months following blast exposure. These studies support alterations in mGluR2 receptors as a key pathophysiological event following blast exposure and provide further support for group II metabotropic receptors as therapeutic targets in the neurobehavioral effects that follow blast injury.

Comparison of outcomes following surgical resection, percutaneous ablation or stereotactic body radiation therapy in early-stage, solitary and small (≤3 cm) treatment-naïve hepatocellular carcinoma

INTRODUCTION

Stereotactic body radiation therapy (SBRT) is associated with high local control rates in hepatocellular carcinoma (HCC). This study reports the outcomes of SBRT compared to surgical resection (SR) and percutaneous ablation (PA) for treatment-naïve, solitary HCCs ≤3 cm.

METHODS

This was a retrospective study of patients with BCLC stage 0/A HCC with a single ≤3 cm lesion, treated with curative intent between 2016 and 2020. SBRT was used for patients considered unsuitable for SR or PA. The co-primary endpoints were progression-free survival (PFS) and overall survival (OS). The secondary endpoints were treatment-related clinical toxicity rates and local control (LC) rates.

RESULTS

There were 112 patients included in this study. SBRT was delivered in 36 patients (32.1%), 51 had PA (45.5%) and 25 underwent SR (22.3%). Median follow-up was 23 months (range, 3-60 months) from diagnosis. The 3-year PFS and OS were 67% and 69% following SBRT, 55% and 80% following PA, and 85% and 100% following SR, respectively. Patients in the SR cohort had significantly better 3-year PFS and OS compared to SBRT and PA groups (p = 0.03 and p = 0.04, respectively). There was no significant difference in PFS (p = 0.15) or OS (p = 0.23) between SBRT and PA treated patients. The 3-year LC rate for the entire cohort was 98%.

CONCLUSIONS

In patients with treatment-naïve, early-stage solitary HCCs ≤3 cm, SBRT was associated with comparable PFS, OS and LC outcomes to PA. SBRT should be considered as a curative intent therapy to avoid treatment stage migration in this favourable prognostic cohort of patients.

Definitive Stereotactic Body Radiation Therapy in Early-Stage Solitary Hepatocellular Carcinoma: An Australian Multi-Institutional Review of Outcomes

AIMS

Standard curative options for early-stage, solitary hepatocellular carcinoma (HCC) are often unsuitable due to liver dysfunction, comorbidities and/or tumour location. Stereotactic body radiation therapy (SBRT) has shown high rates of local control in HCC; however, limited data exist in the treatment-naïve, curative-intent setting. We report the outcomes of patients with solitary early-stage HCC treated with SBRT as first-line curative-intent therapy.

MATERIALS AND METHODS

A multi-institutional retrospective study of treatment-naïve patients with Barcelona Clinic Liver Cancer stage 0/A, solitary ≤5 cm HCC, Child-Pugh score (CPS) A liver function who underwent SBRT between 2010 and 2019 as definitive therapy. The primary end point was freedom from local progression. Secondary end points were progression-free survival, overall survival, rate of treatment-related clinical toxicities and change in CPS >1.

RESULTS

In total, 68 patients were evaluated, with a median follow-up of 20 months (range 3-58). The median age was 68 years (range 50-86); 54 (79%) were men, 62 (91%) had cirrhosis and 50 (74%) were Eastern Cooperative Oncology Group 0. The median HCC diameter was 2.5 cm (range 1.3-5) and the median prescription biologically effective dose with a tumour a/b ratio of 10 Gy (BED10) was 93 Gy (interquartile range 72-100 Gy). Two-year freedom from local progression, progression-free survival and overall survival were 94.3% (95% confidence interval 86.6-100%), 59.5% (95% confidence interval 46.3-76.4%) and 88% (95% confidence interval 79.2-97.6%), respectively. Nine patients (13.2%) experienced grade ≥2 treatment-related clinical toxicities. A rise >1 in CPS was observed in six cirrhotic patients (9.6%).

CONCLUSION

SBRT is an effective and well-tolerated option to consider in patients with solitary, early-stage HCC. Prospective, randomised comparative studies are warranted to further refine its role as a first-line curative-intent therapy.

Late chronic local inflammation, synaptic alterations, vascular remodeling and arteriovenous malformations in the brains of male rats exposed to repetitive low-level blast overpressures

In the course of military operations in modern war theaters, blast exposures are associated with the development of a variety of mental health disorders associated with a post-traumatic stress disorder-related features, including anxiety, impulsivity, insomnia, suicidality, depression, and cognitive decline. Several lines of evidence indicate that acute and chronic cerebral vascular alterations are involved in the development of these blast-induced neuropsychiatric changes. In the present study, we investigated late occurring neuropathological events associated with cerebrovascular alterations in a rat model of repetitive low-level blast-exposures (3 × 74.5 kPa). The observed events included hippocampal hypoperfusion associated with late-onset inflammation, vascular extracellular matrix degeneration, synaptic structural changes and neuronal loss. We also demonstrate that arteriovenous malformations in exposed animals are a direct consequence of blast-induced tissue tears. Overall, our results further identify the cerebral vasculature as a main target for blast-induced damage and support the urgent need to develop early therapeutic approaches for the prevention of blast-induced late-onset neurovascular degenerative processes.

Transcranial Laser Therapy Does Not Improve Cognitive and Post-Traumatic Stress Disorder-Related Behavioral Traits in Rats Exposed to Repetitive Low-Level Blast Injury

Many military veterans who experienced blast-related traumatic brain injuries (TBIs) in the conflicts in Iraq and Afghanistan suffer from chronic cognitive and mental health problems, including post-traumatic stress disorder (PTSD). Transcranial laser therapy (TLT) uses low-power lasers emitting light in the far- to near-infrared ranges. Beneficial effects of TLT have been reported in neurological and mental-health-related disorders in humans and animal models, including TBI. Rats exposed to repetitive low-level blast develop chronic cognitive and PTSD-related behavioral traits. We tested whether TLT treatment could reverse these traits. Rats received a 74.5-kPa blast or sham exposures delivered one per day for 3 consecutive days. Beginning at 34 weeks after blast exposure, the following groups of rats were treated with active or sham TLT: 1) Sham-exposed rats (n = 12) were treated with sham TLT; 2) blast-exposed rats (n = 13) were treated with sham TLT; and 3) blast-exposed rats (n = 14) were treated with active TLT. Rats received 5 min of TLT five times per week for 6 weeks (wavelength, 808 nm; power of irradiance, 240 mW). At the end of treatment, rats were tested in tasks found previously to be most informative (novel object recognition, novel object localization, contextual/cued fear conditioning, elevated zero maze, and light/dark emergence). TLT did not improve blast-related effects in any of these tests, and blast-exposed rats were worse after TLT in some anxiety-related measures. Based on these findings, TLT does not appear to be a promising treatment for the chronic cognitive and mental health problems that follow blast injury.

Low-level blast exposure induces chronic vascular remodeling, perivascular astrocytic degeneration and vascular-associated neuroinflammation

Cerebral vascular injury as a consequence of blast-induced traumatic brain injury is primarily the result of blast wave-induced mechanical disruptions within the neurovascular unit. In rodent models of blast-induced traumatic brain injury, chronic vascular degenerative processes are associated with the development of an age-dependent post-traumatic stress disorder-like phenotype. To investigate the evolution of blast-induced chronic vascular degenerative changes, Long-Evans rats were blast-exposed (3 × 74.5 kPa) and their brains analyzed at different times post-exposure by X-ray microcomputed tomography, immunohistochemistry and electron microscopy. On microcomputed tomography scans, regional cerebral vascular attenuation or occlusion was observed as early as 48 h post-blast, and cerebral vascular disorganization was visible at 6 weeks and more accentuated at 13 months post-blast. Progression of the late-onset pathology was characterized by detachment of the endothelial and smooth muscle cellular elements from the neuropil due to degeneration and loss of arteriolar perivascular astrocytes. Development of this pathology was associated with vascular remodeling and neuroinflammation as increased levels of matrix metalloproteinases (MMP-2 and MMP-9), collagen type IV loss, and microglial activation were observed in the affected vasculature. Blast-induced chronic alterations within the neurovascular unit should affect cerebral blood circulation, glymphatic flow and intramural periarterial drainage, all of which may contribute to development of the blast-induced behavioral phenotype. Our results also identify astrocytic degeneration as a potential target for the development of therapies to treat blast-induced brain injury.

Unconventional animal models for traumatic brain injury and chronic traumatic encephalopathy

Traumatic brain injury (TBI) is one of the main causes of death worldwide. It is a complex injury that influences cellular physiology, causes neuronal cell death, and affects molecular pathways in the brain. This in turn can result in sensory, motor, and behavioral alterations that deeply impact the quality of life. Repetitive mild TBI can progress into chronic traumatic encephalopathy (CTE), a neurodegenerative condition linked to severe behavioral changes. While current animal models of TBI and CTE such as rodents, are useful to explore affected pathways, clinical findings therein have rarely translated into clinical applications, possibly because of the many morphofunctional differences between the model animals and humans. It is therefore important to complement these studies with alternative animal models that may better replicate the individuality of human TBI. Comparative studies in animals with naturally evolved brain protection such as bighorn sheep, woodpeckers, and whales, may provide preventive applications in humans. The advantages of an in-depth study of these unconventional animals are threefold. First, to increase knowledge of the often-understudied species in question; second, to improve common animal models based on the study of their extreme counterparts; and finally, to tap into a source of biological inspiration for comparative studies and translational applications in humans.

Repetitive low-level blast exposure improves behavioral deficits and chronically lowers Aβ42 in an Alzheimer's disease transgenic mouse model

Public awareness of traumatic brain injury (TBI) in the military increased recently because of the conflicts in Iraq and Afghanistan where blast injury was the most common mechanism of injury. Besides overt injuries, concerns also exist over the potential adverse consequences of subclinical blast exposures, which are common for many service members. TBI is a risk factor for the later development of neurodegenerative diseases, including Alzheimer's disease (AD)-like disorders. Studies of acute TBI in humans and animals have suggested that increased processing of the amyloid precursor protein (APP) towards the amyloid beta protein (Aβ) may explain the epidemiological associations with AD. However, in a prior study we found in both rat and mouse models of blast overpressure exposure (BOP), that rather than increasing, rodent brain Aβ42 levels were decreased following acute blast exposure. Here we subjected APP/presenilin 1 transgenic mice (APP/PS1 Tg) to an extended sequence of repetitive low-level blast exposures (34.5 kPa) administered three times per week over 8 weeks. If initiated at 20 weeks of age, these repetitive exposures, which were designed to mimic human subclinical blast exposures, reduced anxiety and improved cognition as well as social interactions in APP/PS1 Tg mice, returning many behavioral parameters in APP/PS1 Tg mice to levels of non-transgenic wild type mice. Repetitive low-level blast exposure was less effective at improving behavioral deficits in APP/PS1 Tg mice when begun at 36 weeks of age. While amyloid plaque loads were unchanged, Aβ42 levels and Aβ oligomers were reduced in brain of mice exposed to repetitive low-level blast exposures initiated at 20 weeks of age, although levels did not directly correlate with behavioral parameters in individual animals. These results have implications for understanding the nature of blast effects on the brain and their relationship to human neurodegenerative diseases.

Laterality and region-specific tau phosphorylation correlate with PTSD-related behavioral traits in rats exposed to repetitive low-level blast

Military veterans who experience blast-related traumatic brain injuries often suffer from chronic cognitive and neurobehavioral syndromes. Reports of abnormal tau processing following blast injury have raised concerns that some cases may have a neurodegenerative basis. Rats exposed to repetitive low-level blast exhibit chronic neurobehavioral traits and accumulate tau phosphorylated at threonine 181 (Thr181). Using data previously reported in separate studies we tested the hypothesis that region-specific patterns of Thr181 phosphorylation correlate with behavioral measures also previously determined and reported in the same animals. Elevated p-tau Thr181 in anterior neocortical regions and right hippocampus correlated with anxiety as well as fear learning and novel object localization. There were no correlations with levels in amygdala or posterior neocortical regions. Particularly striking were asymmetrical effects on the right and left hippocampus. No systematic variation in head orientation toward the blast wave seems to explain the laterality. Levels did not correlate with behavioral measures of hyperarousal. Results were specific to Thr181 in that no correlations were observed for three other phospho-acceptor sites (threonine 231, serine 396, and serine 404). No consistent correlations were linked with total tau. These correlations are significant in suggesting that p-tau accumulation in anterior neocortical regions and the hippocampus may lead to disinhibited amygdala function without p-tau elevation in the amygdala itself. They also suggest an association linking blast injury with tauopathy, which has implications for understanding the relationship of chronic blast-related neurobehavioral syndromes in humans to neurodegenerative diseases.

Progressive Cognitive and Post-Traumatic Stress Disorder-Related Behavioral Traits in Rats Exposed to Repetitive Low-Level Blast

Many military veterans who experienced blast-related traumatic brain injuries (TBI) in the conflicts in Iraq and Afghanistan currently have chronic cognitive and mental health problems including post-traumatic stress disorder (PTSD). Besides static symptoms, new symptoms may emerge or existing symptoms may worsen. TBI is also a risk factor for later development of neurodegenerative diseases. In rats exposed to repetitive low-level blast overpressure (BOP), robust and enduring cognitive and PTSD-related behavioral traits develop that are present for at least one year after blast exposure. Here we determined the time-course of the appearance of these traits by testing rats in the immediate post-blast period. Three cohorts of rats examined within the first eight weeks exhibited no behavioral phenotype or, in one cohort, features of anxiety. None showed the altered cued fear responses or impaired novel object recognition characteristic of the fully developed phenotype. Two cohorts retested 36 to 42 weeks after blast exposure exhibited the expanded behavioral phenotype including anxiety as well as altered cued fear learning and impaired novel object recognition. Combined with previous work, the chronic behavioral phenotype has been observed in six cohorts of blast-exposed rats studied at 3-4 months or longer after blast injury, and the three cohorts studied here document the progressive nature of the cognitive/behavioral phenotype. These studies suggest the existence of a latent, delayed emerging and progressive blast-induced cognitive and behavioral phenotype. The delayed onset has implications for the evolution of post-blast neurobehavioral syndromes in military veterans and its modeling in experimental animals.

The clinical efficacy of PSMA PET/MRI in biochemically recurrent prostate cancer compared with standard of care imaging modalities and confirmatory histopathology: results of a single-centre, prospective clinical trial

Prospective evidence for the clinical role and efficacy of prostate specific membrane antigen (PSMA) positron emission tomography (PET)/magnetic resonance imaging (MRI) combining MRI characterization and localization of lesions with PET avidity in comparison to conventional imaging is limited. In a prospective clinical trial, we aimed to evaluate the diagnostic yield and therapeutic impact of PSMA PET/MRI in men with biochemical recurrence (BCR) following curative therapy. A single-centre, prospective clinical trial at the Princess Alexandra Hospital recruited 30 patients with BCR. Patients underwent PSMA PET/MRI and concurrent conventional CT chest, abdomen, pelvis and whole-body bone scan. Biopsy was performed when safety possible for histological correlation of identified lesions. Clinical efficacy and impact of PSMA PET findings were evaluated. 30 patients with BCR were recruited (median PSA 0.69 ng/ml). PSMA avid lesions were present in 21 patients (70%). 23 patients were previously treated with definitive surgery, 6 patients received external beam radiotherapy and 1 patient had low dose rate brachytherapy. A total of 8 of 9 lesions biopsied were positive (88.9% histological correlation). PSMA PET/MRI detected local recurrence (p = 0.005) and pelvic lesions (p = 0.06) more accurately than conventional imaging. PSMA PET/MRI may be useful in staging men with biochemical recurrence, especially when PSA is low. Our data demonstrates a high detection rate, especially for locally recurrent disease, and highlights the role of this modality when PSA is low. This modality has the potential to significantly improve prostate cancer detection and may have implications for earlier salvage treatment, avoidance of futile local therapy and change patient management to lead to improved outcomes.

Efficacy and Toxicity of Stereotactic Body Radiotherapy for Early to Advanced Stage Hepatocellular Carcinoma - Initial Experience From an Australian Liver Cancer Service

AIMS

Intrahepatic progression remains the predominant mode of cancer-related death in hepatocellular carcinoma (HCC) underscoring the need for effective local therapies. We report our initial experience with liver stereotactic body radiotherapy (SBRT) in the management of early to advanced stage HCC at an Australian tertiary liver cancer service.

MATERIALS AND METHODS

Patients with liver-confined HCC unsuitable for surgical resection or thermal ablation treated with SBRT between October 2013 and December 2018 were retrospectively evaluated. The primary end point was freedom from local progression. Secondary end points were progression-free survival, disease-specific survival, overall survival and toxicity.

RESULTS

Ninety-six patients were treated for 112 lesions (median size 3.8 cm, range 1.5-17 cm). The median follow-up was 13 months (range 3-65). Forty-six patients had received prior local therapies (median 1, range 1-5), 83 (86%) patients had cirrhosis with baseline Child-Pugh scores of A (88%) and B7-8 (12%). Fifty-nine (61%) patients had Barcelona Clinic Liver Cancer (BCLC) stage 0/A disease and 37 (39%) had stage B/C. Macrovascular invasion was present in 20 (21%). The median biologically effective dose (BED₁₀) was 86 and 60 Gy for the BCLC 0/A and B/C cohorts, respectively. Freedom from local progression at 18 months was 94% for BCLC 0/A and 74% for BCLC B/C. Progression-free survival and overall survival at 12 months were 80 and 95% for BCLC 0/A and 40 and 71% for BCLC B/C, respectively. Five patients (7%) with cirrhosis and without disease progression had an increase in Child-Pugh score >1 within 3 months of SBRT, four of whom had intercurrent infections. Clinical toxicities grade ≥2 were reported in 20% of patients.

CONCLUSION

SBRT is an effective ablative modality for early stage HCC with low rates of significant toxicity. Lower dose SBRT can provide durable local control for advanced stage HCC. However, out-of-field relapse remains common, providing a rationale to investigate SBRT in combination with other therapies.

Engaging Future Clinical Oncology Researchers: An Initiative to Integrate Teaching of Biostatistics and Research Methodology into Specialty Training

AIMS

To evaluate the learner's perspectives on a novel workshop programme designed to improve skills in biostatistics, research methodology and critical appraisal in oncology.

MATERIALS AND METHODS

Trainees were surveyed anonymously at the completion of each annual workshop from 2012 to 2015. In total, 103 trainees in years 2-4 of training in radiation oncology responded, giving a 94% survey response rate. A 1 day workshop, designed by biostatisticians and radiation oncologist facilitators, is the central component of a programme teaching skills in biostatistics, research methods and critical appraisal. This links short didactic lectures about statistical concepts to interactive trainee discussions around discipline-related publications.

RESULTS

The workshop was run in conjunction with the major radiation oncology clinical trials group meeting with alternating programmes (A and B). Most of the participants (44-47/47 for A and 48-55/56 for B), reported that their understanding of one or more individual topics improved as a result of teaching. Refinement of the workshop over time led to a more favourable perception of the 'optimal' balance between didactic/interactive teaching: nine of 27 (33%) 'optimal' responses seen in 2013 compared with 23 of 29 (79%) in 2015 (P < 0.001). Commonly reported themes were: clinician facilitators and access to biostatisticians helped contextualise learning and small group, structured discussions provided an environment conducive to learning.

CONCLUSIONS

Overall, radiation oncology trainees reported positive perceptions of the educational value of this programme, with feedback identifying areas where this resource might be improved. This model could readily be adapted to suit other medical disciplines and/or other training environments, using specialty-specific research to illuminate key statistical concepts.

A case of neurosyphilis with a florid Jarisch-Herxheimer reaction

A 37 year old man with a 2 year history of progressive cognitive decline, unilateral tinnitus and deafness presented with complex partial seizures and a fever. On examination there was a sluggish right pupillary response but no other abnormal findings. Serum and CSF syphilis serology were both strongly positive. High dose intravenous penicillin therapy was complicated by a severe Jarisch-Herxheimer reaction (JHR) characterised by fever, obtundation, fluctuating upper motor neuron signs and complex visual and auditory hallucinations. These symptoms resolved over three days and the course of penicillin was completed. At discharge the patient's cognitive functioning was unchanged from the pretreatment state. He made gradual improvement over the following months but remains unable to live alone or work. Clinical, pathologic and radiologic findings of neurosyphilis are reviewed, as is the JHR, a self-limiting, systemic febrile response related to massive cytokine release that can occur in response to treatment of a number of bacterial infections. The similarities in pathophysiology of the JHR and the Septic Shock Syndrome are discussed, with particular reference to use of the JHR as a potential model for therapeutic agents in the treatment of septic shock.

Veno-occlusive disease with multi-organ involvement following actinomycin-D

Actinomycin-D (Act-D) is a rare cause of veno-occlusive disease (VOD). Between 1993 and 1998, we managed 6 patients, all male, median age 19 months (range 6-48 months) who received Act-D for Wilms' tumour (n=4), clear cell sarcoma (n=1) or rhabdomyosarcoma (n=1). VOD presented with a median platelet count of 12 x 10(9)/l, INR 3.8, fibrinogen 16 mg/l, fibrinogen degradation products (FDPs) > or =80 microg/l, aspartate aminotransferase (AST) 6922 IU/l, bilirubin 47 micromol/l. In 3 cases, transient liver dysfunction and thrombocytopenia without neutropenia had been observed after a previous course of Act-D. All six children developed encephalopathy, hepatomegaly, ascites, reversed portal flow and renal impairment. All received mechanical ventilation and two required haemofiltration. The treatment was supportive. Severe Adult Respiratory Distress Syndrome developed in 3 patients, all of whom died. 3 patients recovered. The outcome of VOD with multi-organ failure is poor. Intravascular coagulopathy precedes and characterises severe VOD during Act-D treatment.

Assessment of respiratory drive and muscle function in the pediatric intensive care unit and prediction of extubation failure

BACKGROUND

Extubation failure can result from poor respiratory drive, impaired respiratory muscle function, or excessive inspiratory load. Measurement of airway pressure changes either during tidal breathing or after end-expiratory occlusion allows assessment of respiratory drive and muscle function.

OBJECTIVE

To determine whether the results of airway pressure measurements characterized children who subsequently failed extubation and identify which test's results had the highest predictive performance.

DESIGN

A prospective study.

SETTING

Pediatric intensive care unit.

PATIENTS

A sample of 42 stable intubated pediatric patients who were judged clinically ready for extubation.

METHODS

A pneumotachograph was placed between the endotracheal tube and ventilator circuit. Airway pressure was measured from the pneumotachograph. The flow and pressure signals were amplified and displayed in real time on a laptop computer. During a temporary disconnection from the ventilator, the airway was occluded at end-expiration and the occlusion maintained for at least five breaths. From the first inspiratory effort during the occlusion, the pressure generated after 0.1 sec of occlusion (P0.1) and the largest negative pressure (PI) were calculated. From the series of breaths during the occlusion, the maximum P0.1 (P0.1 max) and maximum PI (PI max) were determined and P0.1/P0.1 max, PI/PI max and P0.1/PI max calculated. From spontaneous, tidal breaths during ventilatory support the pressure time product was calculated.

RESULTS

Thirty-six (84%) of the children were successfully extubated. The children who failed extubation were characterized by a lower median P0.1 (p <.06), P0.1/P0.1 max, p <.05 and P0.1/PI max (p <.02). P0.1 and P0.1/P0.1 max and performed best in predicting extubation failure (areas under the receiver operator characteristic curves, 0.76 and 0.77 respectively).

CONCLUSION

Assessment of P0.1 was the most useful airway pressure measurement in predicting extubation failure. Assessment of P0.1 may help to characterize children likely to fail extubation.

Comparison of predictors of extubation from mechanical ventilation in children

OBJECTIVE: Unsuccessful extubation from mechanical ventilation increases mortality and morbidity. Therefore, the identification of an accurate predictor of successful extubation is desirable. This study was designed to determine whether the results of easily performed respiratory measurements, particularly if reported as "combined extubation" indices, were better predictors of extubation failure in a pediatric population than were readily available clinical data. DESIGN: Prospective observational study. SETTING: Tertiary pediatric intensive care unit. PATIENTS: All children who required mechanical ventilation for >/=24 hrs during a 12-month period and whose parents gave informed written consent. INTERVENTIONS: Respiratory function measurements were made (on average) 7 hrs (range, 0.2-25.0 hrs) before extubation. Arterial blood gas results were obtained immediately before extubation. The values of each predictor associated with maximum sensitivity and specificity were determined, and the areas under receiver operator characteristic curves were compared to determine the most accurate predictor of successful extubation. MEASUREMENTS AND MAIN RESULTS: A total of 47 children (mean age, 3.90 yrs; range, 0.10-17.3 yrs) were studied; extubation failed in 7. A low tidal volume (<7.5 mL/kg) and a low minute volume (<250 mL/kg) had the highest sensitivities (86% and 71%, respectively) and specificities (61% and 71%, respectively) in predicting extubation failure. The a/A ratio performed least well in predicting extubation failure (area under the receiver operating characteristic curve, 0.51). CONCLUSIONS: Volume measurements during pediatric mechanical ventilation may facilitate successful extubation.

More than medicine. Interview by Chris Serb

For all the business savvy demanded by their work as hospital CEO, info tech chief, or entrepreneur, these doctors say it's their medical background that gives them an edge. They know the needs and routines of physicians firsthand. They come to their jobs with built-in credibility as clinicians. And they understand what it means to care for patients. "It's hard for me to know how we're doing," says one hospital CEO, "if I'm sitting in my office all the time."

24 hour ambulatory blood pressure profiles in the acute phase of stroke

1. Twenty-four hour ambulatory blood pressure monitoring (ABPM) was used to evaluate the blood pressure (BP) changes in acute stroke. 2. Stroke was categorized according to the probable underlying vascular mechanism into lacunar infarction (L), thrombotic infarction (T) and intracerebral haemorrhage (ICH). A total of 37 stroke patients were studied (T = 21, L = 9, ICH = 7). Control patients (n = 15) were acute medical admissions not severely ill or in significant pain. ABPM was performed on day 1 and day 7 following admission. 3. Day 1 mean +/- s.d. 24 h systolic BP (SBP) were L (159 +/- 15.8), ICH (151 +/- 33.4), T (147 +/- 15.2) and controls (134 +/- 17.8). Day 7 mean 24 h SBP were L (138 +/- 9.8), ICH (143 +/- 26.9), T (138 +/- 19) and controls (134 +/- 14.8). In each stroke group BP fell to levels similar to control on day 7, while control mean SBP remained unchanged between days 1 and 7. The highest day 1 BP and the greatest subsequent fall on day 7 occurred for lacunar infarction. Diastolic BP showed similar changes to SBP. 4. The acute stress of hospitalization does not appear to explain elevated BP in acute stroke. Lacunar infarction appears to be particularly associated with temporary BP elevation.

Variation in patient utilities for outcomes of the management of chronic stable angina. Implications for clinical practice guidelines. Ischemic Heart Disease Patient Outcomes Research Team

OBJECTIVE

Although practice guidelines sometimes make recommendations based on symptom severity, they rarely account for how patients feel about their symptoms. To investigate the possible importance of patient preferences in treatment of ischemic heart disease, we assessed attitudes toward symptoms in patients with angina pectoris.

DESIGN

Case series.

SETTING

Ambulatory cardiology clinics at two tertiary care medical centers.

PATIENTS

A total of 220 subjects were selected from 589 patients with chronic stable angina referred from cardiologists to achieve patients samples balanced for sex, race, and angina severity.

MAIN OUTCOME MEASURES

We measured patients' attitudes toward their angina using the rating scale, time trade-off, and standard gamble utility metrics. Reliability of measurements was evaluated by repeating the assessments 2 weeks later on 50 willing patients.

RESULTS

While the mean responses followed the expected patterns (those with more severe Canadian Cardiovascular Society scores chose lower utilities), attitudes toward symptoms varied substantially among patients with similarly severe angina. For example, there was a 33% chance that a patient with class II angina had a time trade-off utility that was lower (ie, more bothered by symptoms) than a patient with more severe angina (class III/IV). This variation in utilities was not due to random error in the assessments.

CONCLUSIONS

Angina patients with similar functional limitation vary considerably in their tolerance for their symptoms, as measured by utilities. Our findings suggest that guidelines for the management of ischemic heart disease should be based on the preferences of the individual patient rather than on symptom severity alone.

Acute renal failure complicating diabetic ketoacidosis

Two previously healthy children, aged 13 and 14 years, respectively, presented with diabetic ketoacidosis. Both children developed acute renal failure, a rare complication of diabetic ketoacidosis and required dialysis.

Acute renal failure complicating diabetic ketoacidosis

Two previously healthy children, aged 13 and 14 years, respectively, presented with diabetic ketoacidosis. Both children developed acute renal failure, a rare complication of diabetic ketoacidosis and required dialysis.

Views from Capitol Hill--11 congressional leaders paint varying reform scenarios. Interview by Marybeth Burke

The following exclusive interviews with top congressional health care leaders were conducted by Washington-based reporter Marybeth Burke. In the interviews, Burke found that congressional health care leaders are optimistic yet cautious that comprehensive health care reform legislation will pass in 1993 under President Clinton. Some members of Congress believe that the election of a president committed to action on the issue drastically improves the outlook for reform. Others say that long-term controversy over reform will not resolve itself overnight. Lawmakers expect the issue to heat up quickly as soon as Clinton hands Congress a legislative reform package, but they are reluctant to predict quick enactment.

Resource use and cost of initial coronary revascularization. Coronary angioplasty versus coronary bypass surgery

Although there is intense interest in the cost-saving potential of therapeutic alternatives, most studies have analyzed hospital charges rather than actual economic costs. To analyze cost differences rigorously, we studied 115 patients undergoing initial elective angioplasty (percutaneous transluminal coronary angioplasty, PTCA) and 274 patients undergoing initial elective surgery (coronary artery bypass graft surgery, CABG). Detailed resource consumption profiles were constructed and used to estimate the cost savings from switching a patient from CABG to PTCA. Four cost-accounting methods were used in the analysis; each method made different assumptions about the costs that would vary and the costs that would be fixed according to the number of procedures performed. The variable costs in the four methods were the 1) cost of supplies, 2) cost of personnel and supplies, 3) average direct costs, and 4) average direct costs plus allocated hospital overhead. The mean hospital charges for CABG patients were $19,644 versus $9,556 for PTCA patients (p less than 0.0001). The estimated cost difference between CABG and PTCA was substantially less than the $10,088 difference in charges, however, with net savings of 19%, 46%, 53%, and 78% of charges using cost-accounting methods 1-4, respectively. Thus, although the initial hospital charges for PTCA are significantly less than for CABG, the actual economic cost savings may be significantly overestimated by the use of hospital charge data.

Early detection of acute myocardial infarction: additional diagnostic information from serum concentrations of myoglobin in patients without ST elevation

The value of the 12 lead electrocardiogram, serum total creatine kinase, creatine kinase MB isoenzyme, and myoglobin for the early detection of infarction was evaluated within one hour of admission to the coronary care unit in 82 consecutive patients with suspected myocardial infarction. The 51 patients in whom infarction was diagnosed during the first 24 hours after admission had a higher prevalence of ST elevation (64% v 11%), higher median serum myoglobin (136 micrograms/l v 34 micrograms/l), higher serum creatine kinase (77 IU/l v 34 IU/l), and higher MB isoenzyme (7 IU/l v 4 IU/l) than those in whom it was not. Stepwise logistic regression analysis in 70 patients in whom the electrocardiogram and serum myoglobin were suitable for analysis showed that serum myoglobin was the variable most closely associated with infarction, and contributed additional diagnostic information when ST elevation was entered into the model first. Serum myoglobin remained associated with myocardial infarction when patients who had had symptoms for less than six hours were analysed. An algorithm based on a rapid agglutination test for myoglobin and ST elevation on the electrocardiogram gave an accurate diagnosis in 82% of patients. This approach gave early and rapid recognition of acute myocardial infarction and warrants further examination.

The use of radionuclide angiography in the diagnosis of coronary artery disease--a logistic regression analysis

We applied logistic regression analysis to a group of 736 patients with chest pain to determine which radionuclide angiographic (RNA) parameters were most useful in the diagnosis of significant coronary artery disease. The most useful parameters were exercise ejection fraction, exercise heart rate, "ischemia score," and the presence of a regional wall motion abnormality at exercise. Ten clinical variables were used in one logistic regression model to estimate each patient's pretest probability of disease. A second logistic regression model considered these clinical variables and the four important RNA parameters to estimate each patient's posttest probability. These models were applied prospectively to a group of 76 patients with chest pain who did not have a high pretest probability of disease. Twenty-four patients (32%) could be diagnosed with 90% probability; 32 patients (42%) could be diagnosed with 85% probability. RNA testing is therefore helpful in the noninvasive diagnosis of coronary artery disease. However, a majority of patients who do have a low or intermediate pretest probability of disease will require additional testing for a definitive diagnosis.