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Biomedical subjects

David M Greer

Publications and source records attributed to David M Greer.

7 recordsLinked to original sources
PubMed2006

Hypothermia for cardiac arrest.

Therapeutic hypothermia for cardiac arrest survivors has emerged as a highly effective means of improving neurologic outcome. There are a number of purported mechanisms by which it is felt to be effective, but the exact mechanism is unknown. This article reviews the biochemical mechanisms of injury occurring in cardiac arrest, as well as the avenues that hypothermia takes to combat this injury. It also reviews the animal model data in support of this, as well as the newer animal studies that may help to improve the field. Several human studies of hypothermia in cardiac arrest have been performed, and this article reviews these for their methods and shortcomings. Our currently recommended guidelines for performing therapeutic hypothermia are presented. With therapeutic hypothermia comes potential risks to the patient, primarily affecting cardiac, metabolic, and hematologic systems, and these risks and their management are discussed. Multiple methods of cooling exist, including selective cranial as well as systemic cooling by internal or external approaches. Finally, the article discusses the current research in the field of hypothermia for cardiac arrest and implications for future practice.

Animals↗
PubMed2006

Mechanisms of injury in hypoxic-ischemic encephalopathy: implications to therapy.

Cardiac arrest survivors commonly suffer ischemic brain injury, and understanding the mechanisms of injury is essential to providing insight for effective therapies for brain protection. Injury can occur at the time of the cardiac arrest and is dependent not only on the duration but also the degree of impaired circulation. Injury can be ongoing even after the return of spontaneous circulation, giving the clinician an additional window of opportunity to treat and protect the injured brain. This section will review the molecular basis of injury with cardiac arrest and will elucidate the different mechanisms of injury between cardiac arrest, pure respiratory arrest, and arrest secondary to toxins (e.g., carbon monoxide). The rationale for multiple postarrest therapies, such as hypothermia and induced hypertension, will also be reviewed.

Animals↗
PubMed2006

Ischemic stroke after electroconvulsive therapy.

Stroke is an exceptionally rare complication of electroconvulsive therapy since modern anesthesia and appropriate medical screening were instituted in the 1950s. Postictal focal neurological deficits mimicking stroke are common, but the advent of acute stroke therapies has made the differentiation of these from true cerebrovascular events critical. We present the first case report of ischemic stroke after electroconvulsive therapy with radiographic confirmation.

Adult↗
PubMed2006

Asymmetric reversible posterior leukoencephalopathy syndrome.

Reversible posterior leukoencephalopathy syndrome (RPLS) is characterized radiographically by magnetic resonance imaging as white matter hyperintensities, which reflect cerebral edema. These changes are typically restricted to the parietal and occipital lobes, and are usually quite symmetric. We report a case of asymmetric RPLS involving only one frontal lobe in a patient with severe hypertension, chronic internal carotid artery stenosis, and ipsilateral vasogenic edema.

Brain Edema↗
PubMed2004

Magnetic resonance imaging improves detection of intracerebral hemorrhage over computed tomography after intra-arterial thrombolysis.

BACKGROUND AND PURPOSE: Unenhanced CT is routinely performed after intra-arterial (IA) thrombolysis. The presence of residual contrast causing staining of injured brain may mimic intracerebral hemorrhage (ICH). We evaluated MRI with diffusion-weighted imaging (DWI) and susceptibility-weighted imaging (SWI) for detection of ICH after IA thrombolysis, specifically in equivocal areas of hyperdensity seen on postprocedure CT, to help guide the decision to use anticoagulation or antiplatelet therapy after the IA thrombolysis. METHODS: We performed a retrospective analysis of 15 consecutive patients who underwent IA thrombolysis for acute stroke between September 2000 and March 2003. Inclusion criteria required an immediate postprocedure CT with a questionable hyperdensity and, within the next 48 hours, an MRI with DWI and/or SWI. RESULTS: All patients had CT regions of hyperdensity that were equivocal for the presence of ICH. All patients subsequently underwent DWI, and 11 also underwent SWI. Eleven of 15 patients had magnetic susceptibility-induced hypointensity in DWI hyperintensity regions, signifying the presence of acute deoxyhemoglobin. Nine of these patients also received SWI, which confirmed the presence of blood within these regions. Follow-up CT on all 11 patients confirmed ICH. In the 4 patients without DWI susceptibility change, 0 were found to have ICH on either SWI (performed in 2 patients) or follow-up CT. MRI reliably detected the presence of ICH in all patients, whereas CT failed to differentiate contrast staining from hemorrhage in 4 of the 15 patients. CONCLUSIONS: MRI is an effective means to detect the presence of blood within an equivocal region on post-IA thrombolysis CT. This may influence the decision to use anticoagulation or antiplatelet therapy.

Adult↗
PubMed2004

Achieving normothermia in patients with febrile subarachnoid hemorrhage: feasibility and safety of a novel intravascular cooling catheter.

INTRODUCTION: Fever is common and difficult to control in patients with subarachnoid hemorrhage (SAH). We have previously shown an inverse relationship between fever and outcome in patients with SAH. MATERIALS/METHODS: This was a prospective, single-arm, feasibility trial in which nine patients with SAH underwent temperature management using an intravascular cooling catheter (ICC) to restore and maintain 24 hours of normothermia (36.5 degrees+/-0.2 degrees C). Enrollment occurred after development of a fever of at least 38.3 degrees C within 7 days of SAH that was refractory to acetaminophen treatment. The ICC was placed at the bedside through an introducer sheath via the femoral vein into the inferior vena cava (IVC). Portable X-ray confirmed placement. RESULTS: Normothermia was achieved in seven of the nine patients treated (78%); it was achieved in 100% of the patients with a 14F catheter (n=4) and in 60% of the patients with a 9F catheter (n=5). The two patients not reaching normothermia were not adequately treated for shivering. All other patients reached normothermia irrespective of intubation status. Overall, normothermia was well tolerated and not discontinued because of discomfort or adverse events. Two incidences of deep vein thrombosis were diagnosis by ultrasound that were not associated with clinical sequelae, and IVC filters were placed. No unanticipated adverse events occurred. DISCUSSION: We have demonstrated that fever can be safely and effectively controlled in patients with SAH for at least 24 hours using an ICC. Future studies are needed to assess the effect of such sustained therapy on outcome in patients with SAH.

Adult↗