Randi Connor-Schuler, BA, MD
Emory University School of Medicine
Atlanta, Georgia
Disclosure information not submitted.
Ofer Sadan, MD, PhD
Dr
Emory University Hospital, United States
Disclosure information not submitted.
Title: Feasibility and Reliability of POCUS TCD in Diagnosing Cerebral Vasospasm in Subarachnoid Hemorrhage
Introduction: Cerebral vasospasm is a common complication in patients admitted with aneurysmal subarachnoid hemorrhage (aSAH). Diagnosis is typically by transcranial Doppler (TCD) or vessel imaging. TCD is non-invasive and lacks radiation or contrast administration, yet requires a dedicated technician. We aimed to evaluate the reliability of point of care ultrasound (POCUS) TCD performed by physicians as compared to formal TCD’s to determine its feasibility as an alternative modality for diagnosing vasospasm at the bedside when such a service is unavailable.
Methods: This was a prospective observational study of patients admitted to the Neuro ICU at a single academic medical center. Three critical care fellows with various experience and comfort level with ultrasound performed point of care TCD’s of the right and left MCA and ICA in patients admitted with aSAH who were undergoing daily TCD’s. POCUS scans were performed within 4 hours of formal TCD’s without receiving interventions for treating vasospasms. The absolute velocities and diagnosis of vasospasm (defined as mean velocity >120cm/s and LR >3) were compared to formal transcranial doppler findings.
Results: There were 177 POCUS evaluations performed in 16 patients. The average time to perform POCUS scans was 7.4 minutes (range 6.6-11.0). 13.3% of scans failed due to lack of sonographic bone windows. Sensitivity was 100% and specificity was 98.9% for POCUS-identified vasospasm with a kappa of 0.969 amongst the scanners. Linear correlation between POCUS and formal TCD results ranged from r 0.44-0.63 for systolic velocities and 0.51-0.64 for mean velocities. When discounting poor quality images, r values improved to 0.83 [95% CI 0.72-0.90, p< 0.0001] for systolic velocities and 0.82 [95% CI 0.71-0.89, p< 0.0001] for mean velocities. Image depth was also independently evaluated, and at a depth of 5-6cm the r=0.76 [95% CI 0.62-0.85, p< 0.0001] for systolic velocities and r=0.79 [95% CI 0.67-0.87, p< 0.0001] for mean velocities.
Conclusions: POCUS TCD’s of the MCA were shown to be a fast, reliable means of identifying vasospasm regardless of prior operator experience. There was a noted improvement in the accuracy of absolute velocities when good quality images were obtained and measurements performed at a depth of 5-6cm, capturing the proximal vessels.