Nurses Can Perform Carotid Scans to Triage TIA Patients

May 19, 2015

VIENNA, Austria — It is feasible to train stroke nurse practitioners to perform carotid ultrasound screening scans to triage patients who present with a transient ischemic attack (TIA) outside of hours when a vascular scientist is unavailable, a new study suggests.

Presenting the study here at the 24th European Stroke Conference (ESC), vascular scientist Helena Wilding, from the Royal Devon and Exeter Hospital, United Kingdom, explained: "In our hospital we have not got a vascular scientist working out of hours, so TIA patients coming in at the weekend have to be admitted while they wait for a carotid ultrasound scan on the Monday," she said. "This puts pressure on hospital beds and leads to a large case load of scans needed to be performed urgently at the beginning of the week."

To try and resolve this issue, they have trialed a scheme in which stroke nurse practitioners perform Doppler carotid scans to triage patients.

"These nurses are already on staff and work over weekends and holidays. They have a sound clinical background and are already involved with this patient cohort," Wilding noted.

The nurses are trained to perform a basic screening carotid scan on a portable scanner, she said. If the scan does not indicate moderate to severe disease, the patient can be sent home and called back as an outpatient later in the week for a more thorough scan by the vascular scientist.

If severe disease is indicated by the scan performed by the nurse, then the patient can be fast tracked for a computed tomography angiogram, if available, or can be admitted for observation with an urgent scan performed by the vascular scientist first thing on Monday.

"We found that this approach is feasible," Wilding concluded. "The cut-off levels used proved appropriate, and no significant disease would have been missed with this protocol. The stroke nurse practitioners tended to ascribe a higher urgency to scans than necessary. They tended to err on the side of caution, with a high rate of false-positives, but we believe these will be reduced with experience as confidence rises," she added.

For the study, a bilateral screening scan was performed by a stroke nurse practitioner on the ward using a GE LOGIQ-e portable scanner. The common carotid artery, the internal carotid artery, and the external carotid artery were identified with B mode and color Doppler, and velocity measurements were taken with specified cut-off values designated as indicating moderate or severe disease.

All patients also underwent a full carotid duplex scan by a vascular scientist, and the results of the two scans were compared.

Of the 94 cases included, the vascular scientist scans identified 59% of patients to be discharged and 41% to be admitted. Of these admissions, the nurses identified 38 true positives, with only one patient discharged incorrectly (false-negative).

However, there were more false-positives in the nurse-performed scans, with nurses admitting 38 patients the vascular scientist thought could be discharged. The nurses did, however, correctly discharge 17 patients (true-negatives). This led to a specificity of 97.4% and a sensitivity of 30.9%.

24th European Stroke Conference (ESC). Presented May 14, 2015.


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