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Thứ Tư, 26 tháng 9, 2012

JUM 10-2012


1.          Abstract 1 of 5

Use of Ultrasound Guidance Improves Central Venous Catheter Insertion Success Rates Among Junior Residents

Objectives—The purpose of this study was to determine whether junior residents had higher rates of first cannulation and overall success at central venous catheter insertions with the use of ultrasound (US) guidance compared to the landmark technique.

Methods—We conducted a secondary analysis of data from a prospective randomized controlled study of junior residents from January 2007 through September 2008, which assessed the impact of simulation training on central venous catheter insertion success rates. Blinded independent raters observed in-hospital central venous catheter insertions using a procedural checklist. Success at first cannulation and successful insertion were the primary outcomes. Secondary outcomes included rates of technical errors and mechanical complications.

Results—Independent raters observed 480 central venous catheter insertions by 115 residents. Successful first cannulation occurred in 27% of landmark compared to 49% of dynamic US-guided (P < .01), and 50% of static US-guided (P = .01) cannulations. Insertion success occurred for 55% of landmark compared to 80% of dynamic US-guided (P < .01) and 80% of static US-guided (P < .01) cannulations. Dynamic US guidance was associated with increased odds of first cannulation success compared to the landmark technique (odds ratio [OR], 2.24; 95% confidence interval [CI], 1.37–3.67) and successful insertion (OR, 3.80; 95% CI, 2.34–6.19). Static US guidance was associated with increased odds of first cannulation success compared to the landmark technique (OR, 2.59; 95% CI, 1.25–5.39) and successful insertion (OR, 3.48; 95% CI, 1.54–7.87). The results were independent of central venous catheter insertion training, patient comorbidities, and resident specialties. There was no difference related to mechanical complications between the procedures.

Conclusions—Dynamic and static US guidance during central venous catheter insertion was associated with improved in-hospital first cannulation rates and overall success rates of insertions by junior residents.

o        © 2012 by the American Institute of Ultrasound in Medicine

2.          Abstract 2 of 5

Detection of Free Intraperitoneal Fluid in Healthy Young Men

Objectives—Free intraperitoneal fluid is a secondary sign of abdominal disorders. The detection of small volumes of fluid has been documented as a normal finding in women of childbearing age and also in pediatric sonography. However, the finding of free fluid in asymptomatic men has not been similarly documented by sonography. We postulate that with high-frequency linear probes, small volumes of fluid may be detected in asymptomatic men without underlying abdominal disorders.

Methods—Ten healthy male volunteers underwent targeted abdominal sonographic examinations after an overnight fast and in an immediate postprandial state. The findings were documented, and representative images were saved for analysis.

Results—We found small slivers or geometric collections of fluid between bowel loops in 4 of the 10 volunteers. No obvious correlation between the detection of fluid and the nutritional or hydration status of the patient was identified.

Conclusions—The findings suggest that small volumes of pelvic free fluid in healthy men can be normal and do not necessarily indicate underlying disorders. The role of free fluid identification as an indicator of major intra-abdominal disorders must be viewed with caution and with careful clinical correlation.

o        © 2012 by the American Institute of Ultrasound in Medicine

3.       Abstract 3 of 5 
Antegrade Internal Carotid Artery Collateral Flow and Cerebral Blood Flow in Patients With Common Carotid Artery Occlusion

Objectives—To determine the incidence of antegrade internal carotid artery collateral flow in patients with common carotid artery occlusion, which artery supplies blood to the internal carotid artery, and whether the flow affects regional cerebral blood flow in the middle cerebral artery territory.

Methods—We determined the incidence of antegrade internal carotid artery collateral flow and identified its arterial origins using carotid sonography in 10 patients with common carotid artery occlusion and evaluated middle cerebral artery territory regional cerebral blood flow by single-photon emission computed tomography in these patients and 30 age- and sex-matched patients with internal carotid artery occlusion.

Results—Six (60%) of the 10 patients with common carotid artery occlusion had antegrade internal carotid artery collateral flow, which was supplied through the carotid bifurcation from retrograde flow of the external carotid artery in 5 and by a small artery directly into the internal carotid artery in 1. The regional cerebral blood flow ipsilateral to the occlusion at rest was higher in patients with common carotid artery occlusion than those with internal carotid artery occlusion (mean ± SD, 40.4 ± 8.5 versus 34.3 ± 6.2 mL/100 g/min; P = .02). The regional cerebral blood flow was significantly higher in the 6 patients with antegrade internal carotid artery flow than those with internal carotid artery occlusion at rest (42.2 ± 7.2 versus 34.3 ± 6.2 mL/100 g/min; P= .02) but not in the other 4 patients without antegrade internal carotid artery flow.

Conclusions—Antegrade collateral internal carotid artery flow was found in 60% of patients with common carotid artery occlusion and was mainly supplied by retrograde external carotid artery flow. It contributes to maintenance of middle cerebral artery territory regional cerebral blood flow.

o        © 2012 by the American Institute of Ultrasound in Medicine

4.          Abstract 4 of 5

Ophthalmic Artery Doppler Velocimetric Values in Pregnant Women at Risk for Preeclampsia

Objectives—The purposes of this study were to describe ophthalmic artery Doppler parameters in pregnant women at risk for preeclampsia in the second trimester, compare them with reference values described in women with healthy pregnancies, and evaluate the association between gestational age and Doppler parameters.

Methods—We conducted an observational study with prospective data collection in which measurements of 7 ophthalmic artery Doppler parameters were obtained in 274 women at 20 to 28 weeks’ gestation with clinical risk factors for preeclampsia. The following measurements were obtained: peak systolic velocity, mesodiastolic velocity, mean velocity, end-diastolic velocity, resistive index, pulsatility index, and peak ratio. The observed Doppler values were compared with reference values by a 1-sample t test. To test for linear associations between gestational age and Doppler parameters, the Pearson correlation coefficient was used.

Results—Significantly higher ophthalmic artery Doppler velocimetric parameters were observed when compared with the reference values. The mean values of these parameters ± SD were as follows: peak systolic velocity, 37.9 ± 10.3 cm/s (reference, 34.2 cm/s; P < .001); end-diastolic velocity, 7.2 ± 3.1 cm/s (reference, 6.8 cm/s; P = .03); resistive index, 0.81 ± 0.07 (reference, 0.70; P < .001); pulsatility index, 2.17 ± 0.53 (reference, 1.80; P < .001); and peak ratio, 0.53 ± 0.12 (reference, 0.40; P < .001). There was no correlation between the Doppler parameters and gestational age.

Conclusions—Ophthalmic Doppler parameters of women at risk for preeclampsia are significantly higher than reference values for healthy pregnancies, which may indicate an inadequate vascular response to persistent peripheral resistance. Gestational age during the second trimester is not associated with ophthalmic artery Doppler parameters in pregnant women at risk for preeclampsia.

o        © 2012 by the American Institute of Ultrasound in Medicine


5.          Abstract 5 of 5Technical Innovations

Color M-Mode Sonography for Evaluation of Fetal Arrhythmias

Fetal arrhythmias can be challenging to diagnose, even with the use of 2-dimensional, M-mode, and spectral Doppler sonography of myocardial or blood flow signals to determine the rate, synchrony, and timing. Color Doppler sonography combined with M-mode echocardiography uses the myocardium and blood flow to provide a robust evaluation of cardiac rhythm. Limited descriptions of color M-mode sonography have been published. This article describes the systematic application of the color M-mode technique using 4 specific clinical case examples and contrasts this technique with more conventional approaches to fetal arrhythmia diagnosis.

o        © 2012 by the American Institute of Ultrasound in Medicine

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