[Spectral analysis of the arterial pulse during extracorporeal circulation. Experimental study in dogs]. / Análise espectral do pulso arterial durante a circulação extracorpórea. Estudo experimental em cães.

PURPOSE: Spectral analysis of arterial pulse was performed during cardiopulmonary bypass with both pulsatile and continuous flow in order to evaluate the pulse model best suitable to reproduce physiological circulatory conditions. MATERIAL AND METHODS: Ten adult mongrel dogs were submitted to cardiopulmonary bypass with a roller pump for continuous flow and pulsatile flow pump in parallel. The physiological pressure waves, the roller pump waves and the pulsatile pump flow waves were recorded. During the pulsatile flow we varied the ejection period of the pump in relation to the total cycle by 70%, 60%, 50%, 40% and 30%. RESULTS: The roller pump flow showed a bifid wave followed by single peak wave. During spectral analysis we observed three harmonic components of the same amplitude. The using of the pulsatile pump flow proportioned, by spectral analysis, harmonic components whose amplitudes are inversely proportional for ejection/cycle ratio. CONCLUSION: The fundamental component of the pressure wave during the physiological flow, the pulsatile flow, and that of the roller pump stays the same, if the same blood flow is maintained; the pulse of the flow is inversely proportional to the ejection/cycle ratio; the roller pump produces a flow pattern that cannot be described as laminar; the ejection/cycle ratio of 30% seemed ideal for the performance of pulsatile flow perfusion.