The effects of pulsatile and non-pulsatile cardiopulmonary bypass on renal blood flow and function.

The physiologic effects of pulsatile and non-pulsatile flow in cardiopulmonary bypass were compared in terms of the relationship between different flow rates and what effects these had on pulsatile and non-pulsatile flow. Forty adult mongrel dogs were used in this study and divided into 5 groups, each comprised of 8 animals, according to the flow rate during cardiopulmonary bypass, namely; 40, 60, 80, 100, or 120 ml/kg/min. The animals were perfused with either pulsatile or non-pulsatile flow for 1 hour, given randomly at the same mean flow rate. At flow rates of 80 and 100 ml/kg/min, the mean arterial blood pressure and total peripheral vascular resistance were significantly lower in pulsatile flow than in non-pulsatile flow, and the renal blood flow was significantly greater in pulsatile flow than in non-pulsatile flow. The renal arterial-venous lactate difference was significantly less in pulsatile flow than in non-pulsatile flow at a flow rate of 80 ml/kg/min, and the renal lactate extraction was significantly higher in pulsatile flow than in non-pulsatile flow at the same flow rate. The renal excess lactate was significantly lower in pulsatile flow than in non-pulsatile flow at a flow rate of 100 ml/kg/min. There were no significant differences in these parameters between the two types of perfusion at flow rates of 40, 60 or 120 ml/kg/min. Pulsatile flow was therefore apparently advantageous, when compared to non-pulsatile flow, in terms of hemodynamics, renal circulation, and metabolism of the kidney at flow rates of 80 and 100 ml/kg/min. However, when the flow rate was 120 ml/kg/min, pulsatile flow and non-pulsatile flow had the same effects.

Extravascular lung water with special reference to thoracotomy, manual lung manipulation and rapid fluid transfusion.

An increase in extravascular lung water (EVLW) is indicative of pulmonary edema and the measurement of EVLW has been considered as an important clue for the early detection of pulmonary edema, which is a serious complication of lung surgery. The influence of thoracotomy, manual lung manipulation and rapid fluid transfusion on EVLW were experimentally studied in the lung tissue of dogs, using the double indicator dilution method and comparing it with the drying method. The following results were obtained. 1) EVLW measured by the double indicator dilution method correlated well with EVLW measured by the drying method of tissue at 80 degrees C for 48 hours. 2) EVLW was significantly increased immediately after rapid fluid transfusion. EVLW increased as the osmotic pressure in the transfused fluid became higher. 3) Even the simple procedure of thoracotomy resulted in an increase of EVLW and the addition of manual compression to the lung facilitated this increase of EVLW even further.