This paper introduces the development and animal tests of a miniaturized electrical chest compression device. Based on pulse width modulation technology produced by micro control unit, the device can control the frequency and depth of the compression accurately, as well as perform real-time adjustment. Therefore, it can perform continuous and stable chest compression for long time, which may increase the successful rate of cardiopulmonary resuscitation (CPR). Besides, the device can also produce different types of compression waveforms, including trapezoidal and triangular waveforms. Then, the performance and efficacy of the device was assessed with a rat model of asphyxial cardiac arrest (CA).
Based on the capacitance coupling principle, we studied a capacitive way of non-contact electrocardiogram (ECG) monitoring, making it possible to obtain ECG on the condition that a patient is habilimented. Conductive fabric with a good electrical conductivity was used as electrodes. The electrodes fixed on a bed sheet is presented in this paper. A capacitance comes into being as long as the body gets close to the surface of electrode, sandwiching the cotton cushion, which acts as dielectric. The surface potential generated by heart is coupled to electrodes through the capacitance. After being processed, the signal is suitable for monitoring. The test results show that 93.5% of R wave could be detected for 9 volunteers and ECG with good signal quality could be acquired for 2 burnt patients. Non-contact ECG is harmless to skin, and it has advantages for those patients to whom stickup electrodes are not suitable. On the other hand, it is convenient to use and good for permanent monitoring.
