Using Thoracic Impedance for Identification of Return of Spontaneous Circulation during Resuscitation

Several studies have shown that the carotid pulse check is time-consuming and inaccurate. The sensitivity and specificity of manual pulse check has been reported to be 90% and 55% respectively. It has been suggested that circulatory information can be acquired by measuring the thoracic impedance via the defibrillator pads. We established a dataset of thoracic impedance measurement recorded using a modified automated external defibrillator. By using features describing the impedance waveform resulting from a heart contraction in a pattern recognition framework, we were able to classify periods with systolic blood pressure above or below 80 mmHg with a sensitivity of 90% and a specificity of 82%