[Clinical use of the multi-purpose circuit with a soft reservoir built in inflow side in replacement of the descending thoracic aorta].

The temporary bypass circuit under centrifugal pumping is generally applied for the assisted circulation of the operation for the aneurysm of descending aorta. The estimation of the bypass flow to the abdominal viscera, however, sometimes showed inadequate when excessive bleeding happened during operation. In order to keep constant flow to the lower body, we developed a new circuit, that has soft reservoir built in inflow side of the bypass line. In 8 subjects using this circuit, we studied the usefulness of the circuit and the choice of bypass route based on changes in the hemodynamics during bypass and operative complications in relation to bypass technique. During bypass, perfusion pressure to the lower body was 70-110 mmHg and flow was maintained at more than 21/min even if massive hemorrhage occurred. Comparing arterial bypass with LV bypass, the diastolic pressure in the upper limb was significantly depressed in arterial bypass with reading of 40-50 mmHg. Furthermore, in one case of arterial bypass involving the ascending aorta, false aneurysm is found in the site of cannulation. The rectal temperature dropped with the lapse of time from 35.5 +/- 0.8 degrees C to 33.5 +/- 0.4 degrees c in 120 min. These results indicate that multi-purpose circuit is capable of promptly supplying the circulating volume and is excellent means of providing adequate circulation to the lower body even if massive hemorrhage occurred. And LV bypass should be selected first, because arterial bypass has the hazard of depressing the diastolic pressure in the upper limb and involving complications associated with the insertion of cannula.(ABSTRACT TRUNCATED AT 250 WORDS)