Improved Assessment of Pulsatile Blood Flow During Resuscitation using Doppler Ultrasound

Early defibrillation is critical for successful resuscitation of a sudden cardiac arrest patient. Defibrillators currently do not assess the patient´s heartbeat or blood circulation and the responder has to manually check for the pulse, a procedure known to be very inaccurate. Previously we had developed an ultrasound Doppler based approach to determine the presence of blood flow in the context of resuscitation. Here we extend our earlier work to develop a generalized pulsation index based on a spectral analysis of the Doppler signal. This new method has the advantage to better distinguish between states of pulse and pulselessness, since it aims at capturing the essentially non-sinusoidal behaviour of cardiac activity. In turn, this leads to better sensitivity and specificity for pulsatile flow assessment. The method was demonstrated on data from pigs undergoing cardiac arrest and defibrillation.