The Fibrinolytic Effects of Intermittent Pneumatic Compression: Mechanism of Enhanced Fibrinolysis

BACKGROUND AND OBJECTIVES: Intermittent pneumatic compression (IPC) is an effective form of deep vein thrombosis prophylaxis for general surgery patients. The antithrombotic effect of IPC is thought to be the result of increased venous velocity and stimulation of endogenous fibrinolysis. However, the mechanism of enhanced fibrinolytic activity and the relative effects on normal and postthrombotic veins have not been defined. The purposes of this study are 1) to quantify changes in fibrinolytic activity with IPC; 2) to study the mechanism of fibrinolytic enhancement with IPC; and 3) to evaluate whether postthrombotic patients have the same capacity for fibrinolytic enhancement with IPC as do normal subjects. METHODS: Twelve volunteers (6 normal and 6 postthrombotic) had 5 IPC devices applied for 120 minutes in random fashion, 1 per week x 5 weeks. The devices included single-chamber, sequential, foot, calf, and long-leg compression. Subjects had an indwelling antecubital venous cannula placed for blood drawn at baseline, 60, 120, and 180 minutes after IPC devices were applied. Global fibrinolytic activity (euglobulin fraction, fibrin plate assay), tissue plasminogen activator (tPA) antigen (Ag) and activity (Act), plasminogen activator inhibitor-1 (PAI-1) Ag and Act, alpha-2-antiplasmin-plasmin complexes, and von Willebrand factor (vWF) antigen were assayed. RESULTS: A striking elevation in fibrinolytic activity was noted at 180 minutes with all devices in normal subjects and postthrombotic patients (p = 0.01-0.0001); however, baseline and stimulated fibrinolytic activity was attenuated in postthrombotic patients (<0.03). The tPA-Act increased only in normal subjects (3.8 +/- 1.9%) (p = 0.057), despite a decrease in plasma tPA-Ag, which was observed in both normal subjects (-12.4 +/- 3.8%) (p = 0.009) and patients (-17.2 +/- 3.1%) (p = 0.001). PAI-1-Ag decreased in both normal subjects (-13.4 +/- 3.8%) (p = 0.007) and patients (-12.0 +/- 3.1%) (p = 0.013) with a marked reduction in PAI-1-Act in both normal subjects (p = 0.003) and patients (p = 0.004). There were no changes in vWF, and alpha-2-antiplasmin-plasmin complexes increased only in postthrombotic patients (p = 0.021). CONCLUSIONS: Stimulation of endogenous fibrinolytic activity occurs after IPC, both in normal subjects and postthrombotic patients; however, baseline and overall fibrinolytic response in postthrombotic patients is reduced. The mechanism of increased fibrinolytic activity is likely because of a reduction in PAI-1, with a resulting increase of tPA activity

Bedside sonographic measurement of optic nerve sheath diameter as a predictor of increased intracranial pressure in children

Study objective: We investigate the test performance of emergency physician-performed sonographic measurement of optic nerve sheath diameter for diagnosis of increased intracranial pressure. Methods: Children between the ages of 0 and 18 years with suspected increased intracranial pressure were prospectively recruited from the emergency department and ICU of an urban, tertiary-level, freestanding pediatric facility. Pediatric emergency physicians with goal-directed training in ophthalmic sonography measured optic nerve sheath diameter. Images were recorded and subsequently reviewed by a pediatric ophthalmologist and an ophthalmic sonographer, both of whom were blind to the patient&apos;s clinical condition. Measurements obtained by the ophthalmic sonographer were considered the criterion standard. An optic nerve sheath diameter greater than 4.0 mm in subjects younger than 1 year and greater than 4.5 mm in older children was considered abnormal. The diagnosis of increased intracranial pressure was based on results of cranial imaging or direct measurement of intracranial pressure. Results: Sixty-four patients were recruited, of whom 24 (37%) had a confirmed diagnosis of increased intracranial pressure. The sensitivity of optic nerve sheath diameter as a screening test for increased intracranial pressure was 83% (95% confidence interval [CI] 0.60 to 0.94); specificity was 38% (95% CI 0.23 to 0.54); positive likelihood ratio was 1.32 (95% CI 0.97 to 1.79) and negative likelihood ratio was 0.46 (95% CI 0.18 to 1.23). There was fair to good interobserver agreement between the pediatric emergency physician and ophthalmic sonographer ( 0.52) and pediatric ophthalmologist ( 0.64). Conclusion: The sensitivity and specificity of bedside sonographic measurement of optic nerve sheath diameter is inadequate to aid medical decisionmaking in children with suspected increased intracranial pressure. Pediatric emergency physicians with focused training by a pediatric ophthalmologist familiar with ophthalmic sonography can measure optic nerve sheath diameter accurately. [Ann Emerg Med. 2009;53:785-791.] Provide feedback on this article at the journal&apos;s Web site, www.annemergmed.com

Alternatives to Opioid Education and a Prescription Drug Monitoring Program Cumulatively Decreased Outpatient Opioid Prescriptions.

INTRODUCTION: Deaths have increased, and prescription medications are involved in a significant percentage of deaths. Emergency department (ED) changes to managing acute pain and prescription drug monitoring programs (PDMPs) can impact the potential for abuse. METHODS: We analyzed the impact of a series of quality improvement initiatives on the opioid prescribing habits of emergency department physicians and advanced practice providers. We compared historical prescribing patterns with those after three interventions: 1) the implementation of a PDMP, 2) clinician education on alternatives to opioids (ALTOs), and 3) electronic health record (EHR) process changes. RESULTS: There was a 61.8% decrease in the percentage of opioid-eligible ED discharges that received a prescription for an opioid from 19.4% during the baseline period to 7.4% during the final intervention period. Among these discharges, the cumulative effect of the interventions resulted in a 17.3% decrease in the amount of morphine milligram equivalents (MME) prescribed per discharge from a mean of 104.9 MME/discharge during the baseline period to 86.8 MME/discharge. In addition, the average amount of MME prescribed per discharge became aligned with recommended guidelines over the intervention periods. CONCLUSIONS: Initiating a PDMP and instituting an aggressive ALTO program along with EHR-modified process flows have cumulative benefits in decreasing MME prescribed in an acute ED setting

Substrate stabilisation and small structures in coral restoration:State of knowledge, and considerations for management and implementation

Coral reef ecosystems are under increasing pressure from local and regional stressors and a changing climate. Current management focuses on reducing stressors to allow for natural recovery, but in many areas where coral reefs are damaged, natural recovery can be restricted, delayed or interrupted because of unstable, unconsolidated coral fragments, or rubble. Rubble fields are a natural component of coral reefs, but repeated or high-magnitude disturbances can prevent natural cementation and consolidation processes, so that coral recruits fail to survive. A suite of interventions have been used to target this issue globally, such as using mesh to stabilise rubble, removing the rubble to reveal hard substrate and deploying rocks or other hard substrates over the rubble to facilitate recruit survival. Small, modular structures can be used at multiple scales, with or without attached coral fragments, to create structural complexity and settlement surfaces. However, these can introduce foreign materials to the reef, and a limited understanding of natural recovery processes exists for the potential of this type of active intervention to successfully restore local coral reef structure. This review synthesises available knowledge about the ecological role of coral rubble, natural coral recolonisation and recovery rates and the potential benefits and risks associated with active interventions in this rapidly evolving field. Fundamental knowledge gaps include baseline levels of rubble, the structural complexity of reef habitats in space and time, natural rubble consolidation processes and the risks associated with each intervention method. Any restoration intervention needs to be underpinned by risk assessment, and the decision to repair rubble fields must arise from an understanding of when and where unconsolidated substrate and lack of structure impair natural reef recovery and ecological function. Monitoring is necessary to ascertain the success or failure of the intervention and impacts of potential risks, but there is a strong need to specify desired outcomes, the spatial and temporal context and indicators to be measured. With a focus on the Great Barrier Reef, we synthesise the techniques, successes and failures associated with rubble stabilisation and the use of small structures, review monitoring methods and indicators, and provide recommendations to ensure that we learn from past projects