**5. Conclusion**

Different results in comparison with both groups after analysis of ptO2, MAP and blood

A direct correlation between mean arterial pressure (MAP) and ptO2 was observed in Group A during CPB. Pumped blood flow was continuously maintained at the same calcu‐ lated level. On the other hand, direct correlation between pumped blood flow and MAP was found during mini CPB in Group B. The value of ptO2 was continuous, higher and inde‐

So far, we have no clear explanation for these differences in both groups. The main reason could most likely be due to differences in the amount of circulating blood volume, the possi‐ bility of using a cardiotomy reservoir, and the subsequent need to use catecholamines dur‐

A decrease in the ptO2 levels not correlated with MAP were analysed during CPB, after CPB and in the postoperative course in both groups. This is the most likely cause of decreased circulatory volume resulting in the use of vasopressors (catecholamines). A decrease in body temperature during this phase of the operation leading to peripheral vasoconstriction can al‐

The lower level of acquired hemodilution (higher hematocrit) during the operation, deter‐ mined by a lower filling volume and retrograde autologous priming are major advantages

Supply of oxygen to the tissues during reduced flow of the bypass machine is therefore safe in the case of an increased hematocrit. In the mini CPB group, only 2/3 of the priming fluid was used as opposed to classical CPB and another 1/3 of this fluid was replaced by the pa‐ tient's blood using retrograde autologous priming. The hematocrit provides sufficient ca‐ pacity to supply oxygen in normothermia. A combination of decreased primary filling and a shortened tubing system resulted in an increased hematocrit and concentration of hemoglo‐

In our study a closed integrated system coated with phosphorylcholine was used. The tub‐ ing system was shortened to a minimum, by placing it as close as possible to the patient, to minimalize priming. The system used allowed for partial back-flow of the patient´s own blood (retrograde autologous priming). Coronary suction was not used and neither was a

In comparison to the perfusion parameters of both groups there were no differences during surgery. The monitored values of arterial blood gases were comparable and showed optimal perfusion management in both groups. Likewise, the values in both groups were compara‐

No death, acute renal failure, or stroke occurred in the postoperative course of either group. The only difference noted was in the incidence of postoperative atrial fibrillation with group B (mini CPB) showing better results. This study was limited by a small number of patients.

flow during CPB and postoperative course were found to our greatest surprise.

pendent at this time.

so contribute equally to this phenomenon.

of using perfusion by mini CPB.

bin as expected in Group B (mini CPB).

ble in the early postoperative course.

venous reservoir. No cell saver device was used.

There were no technical perfusion linked complications.

ing perfusion.

114 Artery Bypass

A miniaturized system of CPB enables perfusion with relatively low flow and in normother‐ mic conditions. Monitoring perfusion of skeletal muscle during the operation and our expe‐ rience shows that it is a safe method of perfusion.

Our work experience and the results of this pilot study suggest that a flow decrease in mini CPB is well tolerated by the organism.

The chapter was supported by PRVOUK P 37/04/440.
