Peripheral circulation during nonpulsatile systemic perfusion in chronic awake animals

Peripheral circulation (PC) during nonpulsatile (NP) perfusion is not satisfactorily understood, although it is known that animals can survive with chronic NP flow. In awake goats, PC was analyzed by hemodynamic and hormonal parameters, tissue blood flow of the ear measured by a noninvasive laser Doppler flowmeter, and distribution of the body surface temperature monitored by thermography. An NP systemic circulation was established in five 40-64 kg goats with a centrifugal pump (MD-10, Iwaki Pump, Japan) that replaced a pulsatile ventricular assist device 2 weeks postoperatively; this was done without anesthesia. Nonpulsatile total left heart bypass was obtained, with flow rates of 78-165 ml/kg/min. Systemic vascular resistance and blood adrenalin and noradrenalin levels were not affected by the depulsation. Tissue blood flow during NP perfusion was well maintained and showed comparable values to those during pulsatile systemic circulation. Vasomotion of 10-20 cycles/min was obvious in the tissue blood flow pattern, indicating adequate PC at each sampling point. Thermography before and after depulsation indicated no change of temperature distribution, and displayed warm peripheral areas. In conclusion, PC of animals on chronic NP systemic perfusion is adequately maintained.