Is B-mode ultrasound alone a sufficient screening tool for carotid stenosis? A pilot study.

BACKGROUND: Carotid ultrasound is performed solely in hospital ultrasound departments or outpatient labs, using both B- and Doppler modes. We hypothesize that B-mode without Doppler can be used to classify patients as having carotid stenosis (CS) above or below 50%. Our objective is to determine the frequency with which a CS >50% is found using Doppler when no such stenosis was visible using B-mode. METHODS: This was a retrospective study of 100 patients referred to the stroke clinic and 100 patients referred for carotid endarterectomy (CEA). All patients had an elective carotid ultrasound done at Health Sciences North. The ultrasound reports were mixed together and blinded. Investigators determined if there was a CS of greater or less than 50% based on the carotid diagram. These results were compared to the degree of CS found on Doppler. RESULTS: In the CEA group, there were 198 ultrasounds, with 153 showing a CS of >50%. Only one case of CS >50% was missed by B-mode. In the clinic group, 32 of 192 ultrasounds showed a CS of >50%. None were missed by B-mode. B-mode had a sensitivity and negative predictive value of 100% and a specificity of 65%. CONCLUSION: This study supports the theory that it may be possible to use B-mode ultrasound without Doppler to reliably determine if there is CS above or below 50%. Further research is required before carotid ultrasound using B-mode alone can be recommended.

A comparison of the supraclavicular and infraclavicular views for imaging the subclavian vein with ultrasound.

INTRODUCTION: Ultrasound guidance for central line placement in the subclavian vein (SCV) is more efficient and safer than landmark-based technique. The supraclavicular (SC) approach is an alternative to the infraclavicular (IC) approach, but the research is sparse. The objective was to determine which approach provides the best view. METHODS: This was a prospective anatomical survey of voluntary normovolemic patients. Four experienced emergency physicians and 1 resident scanned the right and left SCVs from SC and IC approaches. They assigned a score for the views obtained on a 5-point Likert scale. RESULTS: Ninety-eight patients were enrolled. Mean Likert scores for the 4 views were: right SC, 4.06 (95% confidence interval [CI], 0.22); right IC, 3.07 (95% CI, 0.25); left SC, 3.82 (95% CI, 0.23); left IC, 3.12 (95% CI, 0.25). When combining data from right and left, the mean score for the SC view was significantly higher than the mean score for the IC view: 3.94 (95% CI, 0.16) vs 3.10 (95% CI, 0.18). The following ratings were obtained: right SC view was good or excellent in 71.5%; left SC view was good or excellent in 66.3%; right IC view was good or excellent in 37.8%; and left IC view was good or excellent in 38.8%. CONCLUSION: The SC approach allows for a better view of the SCV on ultrasound than the IC approach. Future research should determine if this translates to a greater success rate when placing central lines in the SCV.

Defining normal jugular venous pressure with ultrasonography.

OBJECTIVE: Determination of jugular venous pressure (JVP) by physical examination (E-JVP) is unreliable. Measurement of JVP with ultrasonography (U-JVP) is easy to perform, but the normal range is unknown. The objective of this study was to determine the normal range for U-JVP. METHODS: We conducted a prospective anatomic study on a convenience sample of emergency department (ED) patients over 35 years of age. We excluded patients who had findings on history or physical examination suggesting an alteration of JVP. With the head of the bed at 45 degrees, we determined the point at which the diameter of the internal jugular vein (IJV) began to decrease on ultrasonography ("the taper"). Research assistants used 2 techniques to measure U-JVP in all participants: by measuring the vertical height (in centimetres) of the taper above the sternal angle, and adding 5 cm; and by recording the quadrant in the IJV's path from the clavicle to the angle of the jaw in which the taper was located. To determine interrater reliability, separate examiners measured the U-JVP of 15 participants. RESULTS: We successfully determined the U-JVP of all 77 participants (38 male and 39 female). The mean U-JVP was 6.35 (95% confidence interval 6.11-6.59) cm. In 76 participants (98.7%), the taper was located in the first quadrant. Determination of interrater reliability found kappa values of 1.00 and 0.87 for techniques 1 and 2, respectively. CONCLUSION: The normal U-JVP is 6.35 cm, a value that is slightly lower than the published normal E-JVP. Interrater reliability for U-JVP is excellent. The top of the IJV column is located less than 25% of the distance from the clavicle to the angle of the jaw in the majority of healthy adults. Our findings suggest that U-JVP provides the potential to reincorporate reliable JVP measurement into clinical assessment in the ED. However, further research in this area is warranted.

Intra-articular lidocaine for the reduction of posterior shoulder dislocation.

Anterior shoulder dislocations are the most common major joint dislocation seen in emergency departments. Intra-articular lidocaine is a useful method of analgesia for facilitating the reduction of anterior shoulder dislocations. Posterior shoulder dislocations represent a small minority of shoulder dislocations. We present the case of a posterior shoulder reduction in an elderly female whose reduction was performed following the intra-articular injection of lidocaine. Intra-articular lidocaine represents a useful alternative to facilitate the reduction of shoulder dislocations, particularly in patients at higher risk for complications from sedation.