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Biomedical subjects

Robert Silbergleit

Publications and source records attributed to Robert Silbergleit.

6 recordsLinked to original sources
PubMed2003

Neuroprotective effects of hyperbaric oxygen treatment in experimental focal cerebral ischemia are associated with reduced brain leukocyte myeloperoxidase activity.

OBJECTIVE: Hyperbaric oxygen (HBO) reduces cerebral infarct size after middle cerebral artery occlusion (MCAO) in rats through an unknown mechanism. In other forms of injury, cellular protection with HBO is associated with diminished infiltration of polymorphonuclear neutrophils (PMN). We hypothesized that HBO given prior to or after MCAO reduces PMN infiltration into the brain, and that decreased PMN infiltration is associated with improved functional and anatomic outcome. METHODS: Forty rats underwent MCAO and were randomized to pretreatment with HBO (3 ATA) immediately prior to (n=13), or posttreatment immediately after surgery (n=12), or to control (air 1 ATA) (n=15). Five rats underwent sham surgery. Neurologic outcome was measured at 24 h in all animals. Brain myeloperoxidase (MPO) activity (n=22) and infarct volume (n=23) were determined. RESULTS: MPO activity was significantly higher in controls (mean 0.28, 95% C.I. 0.17-0.38) than in the HBO pretreatment group (0.12, 0.08-0.16), HBO posttreatment group (0.16, 0.13-0.19), and the sham group (0.02, -0.02 to 0.05). HBO treated animals also had better neurologic outcomes (pretreatment 1.5, 0.9-2.1, posttreatment 2.6, 2.0-3.2) and smaller infarcts (pretreatment 27%, 18-37%, posttreatment 28%, 19-37%) than controls (neurologic outcome 3.7, 3.1-4.4, infarct volume 39%, 30-48%). Neurologic outcomes correlate better with MPO activity (R(2)=0.75) than with infarct volume (R(2)=0.25). CONCLUSION: These data confirm the neuroprotective effects of HBO in cerebral ischemia and suggest that the mechanism of this action may involve inhibition of PMN infiltration in the injured brain.

Animals↗
PubMed2003

Hyperbaric oxygen reduces neuronal death and improves neurological outcome after canine cardiac arrest.

BACKGROUND AND PURPOSE: Studies suggest that hyperbaric oxygen (HBO) is neuroprotective after experimental cerebral ischemia, but the mechanism is unknown. This study tested the hypotheses that postischemic HBO affords clinical and histopathological neuroprotection after experimental cardiac arrest and resuscitation (A/R) and that this neuroprotection results from improved cerebral oxygen metabolism after A/R. METHODS: Anesthetized adult female beagles underwent A/R and randomization to HBO (2.7-atm absolute [ATA] for 60 minutes, 1 hour after A/R) or control (Po2=80 to 100 mm Hg; 1 ATA). Animals underwent neurological deficit scoring (NDS) 23 hours after A/R. After euthanasia at 24 hours, neuronal death (necrotic and apoptotic) in representative animals was determined stereologically in hippocampus and cerebral neocortex. In experiment 2, arterial and sagittal sinus oxygenation and cerebral blood flow (CBF) were measured. Cerebral oxygen extraction ratio (ERc), oxygen delivery (Do2c), and metabolic rate for oxygen (CMRo2) were calculated (baseline and 2, 30, 60, 120, 180, 240, 300, and 360 minutes after restoration of spontaneous circulation). RESULTS: NDS improved after A/R in HBO animals (HBO, 35+/-14; controls, 54+/-15; P=0.028). Histopathological examination revealed significantly fewer dying neurons in HBO animals; the magnitude of neuronal injury correlated well with NDS. HBO corrected elevations in ERc (peak, 60+/-14% for controls, 26+/-4% for HBO) but did not increase Do2c or CMRo2, which decreased approximately 50% after A/R in both groups. CONCLUSIONS: HBO inhibits neuronal death and improves neurological outcome after A/R; the mechanism of HBO neuroprotection is not due to stimulation of oxidative cerebral energy metabolism.

Animals↗
PubMed2003

Cost-effectiveness of helicopter transport of stroke patients for thrombolysis.

OBJECTIVES: Treatment with intravenous (IV) or intra-arterial (IA) thrombolysis in patients with acute ischemic stroke demands careful patient selection and specialized institutional capabilities. Physicians at hospitals without these resources may prefer patient transfer for acute treatment. Helicopter transport for these patients has been described but without analysis of the effects of its additional cost. The authors examined the cost-effectiveness of helicopter transport for patients with acute stroke. METHODS: Costs per additional good outcome and per quality-adjusted life-year (QALY) were calculated using a computer model. Input variables included flight, thrombolytic agent, and angiography costs; annual cost per patient for long-term care of symptomatic stroke; percentage of transported patients treated; percentage of patients receiving IV versus IA therapy; discount rate; absolute probability of good outcome; annual mortality with and without treatment; and quality-of-life modifier. Sensitivity analysis was performed. RESULTS: Helicopter transport of acute stroke patients to tertiary care centers for thrombolytic therapy costs $35,000 per additional good outcome and $3,700 per QALY for the reference case. Cost-effectiveness was sensitive to the effectiveness of thrombolysis but minimally sensitive to most other input values. Cost per QALY ranged from $0 to $50,000, as the absolute increase in good outcomes (minimal or no deficit) ranged from 20% to 5%. Cost-effectiveness was not sensitive to ranges of helicopter flight costs or the proportion of flown patients undergoing treatment. CONCLUSIONS: This model indicates helicopter transfer of patients with suspected acute ischemic stroke for potential thrombolysis is cost-effective for a wide range of system variables.

Air Ambulances↗
PubMed2002

Filming of patients in academic emergency departments.

With increasing availability and utilization of advanced technologic modalities in medicine, questions frequently arise regarding the appropriate use of recorded images of patients. While recorded images (photography, video, etc.) of patients may often be appropriate for documentation, medical record use, peer review, and teaching, the nonmedical use of recorded images for entertainment or commercial purposes is more problematic, both ethically and procedurally. Practices regarding filming of patients in academic emergency departments are reviewed, and suggested guidelines are provided regarding the appropriate and inappropriate filming of patients.

Academic Medical Centers↗
PubMedDate not supplied

Long-term air medical services system performance using APACHE-II and mortality benchmarking.

OBJECTIVE: Air medical transport programs have been in existence for two decades. During this time, no outcome measures have been developed for these services. The authors examined severity scoring and mortality data from their air medical service to characterize its performance and to identify trends in acuity and mortality over a 15-year period. METHODS: APACHE-II scores derived at the time of transport and hospital mortality data have been concurrently recorded in the flight database for adult transports since 1986. The authors analyzed these data and examined the correlation between APACHE-II score at the time of transport and hospital mortality for the 15-year period 1986-2001. RESULTS: 13,808 adult transports were identified. APACHE data were available for 8,204 patients (59%) and mortality for 10,845 (79%), respectively. The number of transports increased from 935 to 1,231 per year. Mean APACHE-II for all patients was 11.6 +/- 8.4. Overall mortality was 22%. Both patient acuity and mortality were trending upward over time. The correlation between APACHE-II and mortality was close and linear (mortality = 0.018 x APACHE-II -0.0243, R2 = 0.97). CONCLUSIONS: Both severity of illness and mortality of air-transported patients appear to be increasing slowly over time in response to changes in the health care system. The strong correlation between APACHE-II performed at the time of transport and mortality validates this technique for benchmarking. The slope of this correlation is an outcome-based characteristic of system performance that may allow monitoring of a system over time and comparisons between systems.

APACHE↗