Carotid Doppler blood flow measurement during cardiopulmonary resuscitation is feasible: A first in man study.

Objective: High quality chest compressions are the cornerstone of effective cardiopulmonary resuscitation (CPR). There is no available method of real time noninvasive hemodynamic measurement and feedback to inform rescuers of the efficacy of compressions. Ultrasound-based measures of blood flow may provide immediate, noninvasive hemodynamic information. Our objective was to determine the feasibility and safety of using ultrasound to measure blood flow on patients with cardiac arrest.

Methods: Study design This was a prospective cohort study in an emergency department setting. Subjects Included were patients receiving ongoing manual chest compressions for cardiac arrest. Excluded were those less than 18 years of age, incarcerated, pregnant, with neck injury, or obvious traumatic cause of arrest. Scan protocol Physicians recorded blood flow over the common carotid arteries during chest compressions with transverse and longitudinal color flow and Doppler using a portable ultrasound machine (CX30, Philips Healthcare., Andover, MA). Measurements Duration of scan time, and the median values for peak systolic (PSV), end-diastolic (EDV) and mean diastolic (MDV) carotid blood flow velocities were captured. Feasibility was defined as the proportion of eligible subjects upon whom ultrasound was initiated Safety was defined as availability of at least 5 min of scanning time.

Results: Nineteen patients (56% of eligible) where enrolled and had ultrasound measurements attempted during manual compressions. In one patient, scanning was not initiated because ongoing CPR efforts were terminated. Three patients were enrolled but had no images available for review. A total of 15 patients (78% of attempted) had ultrasound imaging saved. Most (n=10, 66%) had scanning times greater than 5 min (median 5 min 59s, interquartile range 3 min 15s to 8 min 25s), median PSV was 67 cms(-1) (IQR 55-106), median EDV was 18 cms(-1) (IQR 12-27), and median MDV was 14 cms(-1) (IQR 9-18).

Conclusions: Ultrasound measurement of common carotid artery blood flow during CPR is feasible. Further studies are necessary to correlate carotid blood flow to other hemodynamic measures and its effects on patient outcomes.