Pharmacological stress echocardiography in the diagnosis of coronary artery disease and myocardial ischaemia: a comparison between dobutamine and dipyridamole.

The objective of this study was to relate regional wall motion abnormalities assessed by dobutamine and dipyridamole stress echocardiography to quantitative measurements of coronary artery stenoses in consecutive patients referred for coronary angiography, and to compare haemodynamic effects of and complications related to the two agents. Patients underwent stress echoes on separate days in random sequence and had coronary angiography within 3 days of stress echocardiography. Echocardiograms were assessed by two investigators unaware of the patients' coronary anatomy. Coronary angiograms were also assessed quantitatively using the computer-assisted Cardiovascular Angiography Analysis System. There were 46 consecutive patients referred for coronary angiography; 28 were using beta-antagonists. Main outcome measures were sensitivity and specificity for dobutamine and dipyridamole stress echocardiography for detection of coronary artery disease (wall motion abnormalities at rest or stress) and myocardial ischaemia (stress induced new wall motion abnormalities). Sensitivity for the detection of myocardial ischaemia was found to be 57% for dobutamine and 64% for dipyridamole. Specificities were 78% and 89% respectively. Sensitivities for detection of coronary artery disease (lesion > or = 50% diameter stenosis) was 79% for dobutamine and 82% for dipyridamole; specificities were 78% and 89% respectively. These differences between the two agents are not significant. There were no severe side effects with either agent. Mean heart rate rose significantly with both tests but was higher with dobutamine; mean systolic blood pressure rose with dobutamine and fell with dipyridamole. It was concluded that dobutamine and dipyridamole stress echocardiography have similar sensitivities and specificities for detection of myocardial ischaemia and coronary artery disease although the haemodynamic effects of the two agents are different. Both are free from serious complications.     

Differential regulation of the growth-associated proteins, GAP-43 and SCG-10, in response to unilateral cortical ablation in adult rats

Synapse replacement after brain injury has been widely documented by anatomical studies in various parts of both the developing and adult nervous system. However, the molecular events that define the specificity of the empirically derived rules of reactive synaptogenesis in different regions of the adult brain remain unclear. In this study we examined the differential regulation of the lesion-induced response of the two growth-associated proteins, superior cervical ganglia-10 and growth-associated protein-43, after unilateral cortex ablation, and determined a hierarchical order for the lesion response from remaining afferent projection neurons originating from the contralateral cortex, ipsilateral thalamus and substantia nigra. We report that in response to unilateral cortex ablation both messenger RNA, by northern blot, and protein, by estern blot, for superior cervical ganglia-10 but not growth-associated protein-43 was increased in the homologous area of the contralateral cortex but not the ipsilateral thalamus or substantia nigra. In addition, the specificity of the superior cervical ganglia-10 response, assessed by combined in situ hybridization and retrograde FluoroGold labeling of striatal afferent neurons, found that superior cervical ganglia-10 messenger RNA was increased prominently in layer V pyramidal neurons of the contralateral corticostriatal pathway but was unchanged in afferent projection neurons from the thalamus and substantia nigra. Furthermore, the increase in both superior cervical ganglia-10 messenger RNA and protein seen at three days postlesion in contralateral corticostriatal neurons coincides in time with the initiation of neurite outgrowth in the deafferented striatum by contralateral corticostriatal axons described in our previous ultrastructural study. However, if cortical input to the striatum was removed bilaterally the lesion-induced response for superior cervical ganglia-10 messenger RNA shifted secondarily to thalamostriatal neurons in the ipsilateral thalamus.

These data provide evidence that superior cervical ganglia-10 and growth-associated protein-43 are differentially regulated in neurons of the contralateral corticostriatal pathway in response to unilateral cortex ablation and suggests that superior cervical ganglia-10 plays a role in the regulation of neurite outgrowth in the adult striatum after brain injury. However, the specific role that superior cervical ganglia-10 may play in reactive synaptogenesis remains unclear. In addition, our data suggest that a hierarchical order exists for the reinnervation of deafferented striatal neurons after unilateral cortex ablation with preference given to homologous axons from the contralateral cortex.     

Piezoelectric sensor determination of arterial pulse wave velocity

Arterial pulse wave velocity (APWV) is a measure of the elasticity (or stiffness) of peripheral arterial blood vessels. The pulse referred to here will be the pressure pulse as opposed to the flow pulse measured by ultrasound Doppler. The pressure pulse velocity varies over the range from about 12 m s(-1) to 15 m s(-1) in stiff peripheral arteries, whereas in normal arteries it has a velocity in the range of 7 to 9 m s(-1). The aim of this project was the development of a fast and easy to use system for the determination of peripheral arterial pulse wave velocity. The principle of the PWV measurement is based on simultaneous measurement of two pulse waves at two different positions, such as the radial artery at the wrist and the brachial artery just above the elbow. By determining the pulse transit time between these points and the distance measured between the two locations, pulse wave velocity may then be calculated. The pressure pulse detection is done by using two piezoelectric sensors which generate a measurable voltage at the output contacts if they are mechanically deformed. The deformation produced voltage is first amplified and filtered and then digitalized with a data acquisition card. The analysis of the data obtained from the sensors includes a filtering process, the calculation of the PWV with three different methods--foot-to-foot, cross-correlation and peak-to-peak-and the determination of the arterial pulse rate. Extensive measurements with human test subjects were carried out to optimize the techniques of data acquisition and analysis. For example, it was found that the best procedure was to hold the sensors in place using elastic straps alone. The data analysis was upgraded with an additional software module, which deletes, in effect, outriders or invalid measurements. With the optimized system, a series involving eight test subjects ranging in age from 22 to 32 years was completed (all normotensive). The arterial pulse wave velocities determined covered a range from 6 m s(-1) to 12 m s(-1), with an average standard deviation of less than 2.5 m s(-1) for individual results. These are slightly higher, but close to published APWV data. The results showed that reproducible results can be obtained with the existing PWV acquirement and analysis system.     

Splenic salvage quantified by uptake of heat-damaged radiolabeled red blood cells. Experimental and clinical studies

We evaluated a noninvasive radionuclide technique to quantify splenic trapping function, which is a key step in the disposition of blood-borne particulates such as poorly opsonized encapsulated microorganisms implicated in hyposplenic fulminant sepsis. Using computerized external gamma imaging, the percentage of splenic uptake of heat-damaged radiolabeled red blood cells was determined in adult Sprague-Dawley rats with eutopic (partial splenectomy) or ectopic (single or multiple autotransplantation) remnants or whole spleens, and in 14 patients with either an intact spleen or splenic remnants after treatment for trauma or hypersplenism. The masses of both eutopic and ectopic remnants correlated directly with the percentage of heat-damaged red blood cell uptake, but the percentage of uptake per gram was higher in eutopic remnants, paralleling more vigorous compensatory growth. In patients, the percentage of heat-damaged red blood cell uptake by remnant spleens was similar to that seen in the rats and, in addition, was supernormal in those with congestive splenomegaly. This noninvasive technique both provides a vivid biplanar image and quantifies blood-borne particle trapping, which is a key splenic function. A heat-damaged red blood cell uptake of less than 15 percent after splenic salvage suggests marginal splenic performance and continued vulnerability to overwhelming sepsis.     

Management of biliary obstruction in patients with unresectable carcinoma of the pancreas.

Clinical and pathologic data from 73 patients with unresectable carcinoma of the pancreas treated from 1980 to 1987 were reviewed to evaluate the efficacy of biliary enteric bypass and percutaneous transhepatic biliary drainage (PTBD) in the treatment of malignant biliary obstruction. Fifty-two patients underwent biliary enteric bypass with no operative deaths and with a 15% operative morbidity. These patients had a median postoperative hospitalization of 12 days. Four patients (8%) eventually developed recurrent jaundice, and three of these were successfully treated with PTBD. The median survival for these 52 patients was 7 months. Twenty-one patients underwent PTBD with an 81% technical-success rate. These patients had a 33% early complication rate and a 33% in-hospital mortality. The median hospitalization was 13 days postdrainage. Of the 14 patients surviving the initial hospitalization, 86% developed late complications requiring 16 hospital admissions and ten emergency room visits for a total of 155 days of hospitalization. The median survival for those patients undergoing PTBD was 4 months from the time of diagnosis and 2 months from the time of catheter drainage. Surgical bypass offers excellent palliation for malignant biliary obstruction with extremely low morbidity and mortality in properly selected patients; PTBD is useful in the treatment of those patients with extensive disease, who are poor surgical candidates, or who have failed previous surgical drainage. There is a role for both of these palliative procedures in the management of patients with biliary obstruction from pancreatic cancer.     

A team approach: implementing a model of care for preventing osteoporosis related fractures

Summary  

The implementation of a multidisciplinary team-based model of care has led to significant increases in identification of patients with osteoporosis who are at risk of refracture, together with improved treatment uptake and ongoing management.     

A Clinical Trial of a New All-in-One Peripheral-Short Catheter

The objectives of this survey were to: 1) understand current peripheral IV stabilization practices within our hospital and 2) evaluate the use of a new closed IV catheter system with a built-in stabilization platform. All medical-surgical patients within an 851-bed acute care hospital with peripheral-short catheters were evaluated within a 3-day period for catheter securement, dwell time, and signs of complications. Additionally, catheter restart data were collected from a renal telemetry unit for 2 weeks. Catheter and dressing protocols were then standardized to a new catheter system with a built-in stabilization platform (Nexiva? Closed Catheter System) and an absorbent transparent dressing (SorbaView^® 2000). After a 2-week trial of the new protocol, catheters were again evaluated for securement and restart data were again collected from the renal telemetry unit. Staff nurse (N = 42) opinions on the new catheter system and dressing combination were sought, as well as a vote on willingness to change to the new catheter system and dressing. Results demonstrate improvement in catheter stabilization (out to 96 hours of dwell-time), decreased restarts, a high clinical preference for the new catheter/dressing system, and a high willingness to convert to the new system. Results indicate that the new closed IV catheter system with a built-in stabilization platform and the transparent absorbent dressing evaluated in this survey may help to improve catheter securement and increase dwell-time. Research studies utilizing more rigorous randomized, controlled comparisons are warranted.