Plöchl W, Orszulak T A, Cook D J, Sarpal R S, Dickerman D L
Department of Anesthesiology, Mayo Clinic, Rochester, MN, USA.
J Cardiothorac Vasc Anesth. 1999 Aug;13(4):441-5. doi: 10.1016/s1053-0770(99)90217-3.
To examine the effects of phenylephrine infusion and increases in pump flow on systemic oxygen supply and demand when they are used to support mean arterial pressure (MAP) during cardiopulmonary bypass (CPB).
Prospective, unblinded study.
The animal cardiopulmonary laboratory at the Mayo Foundation (Rochester, MN).
Twelve pigs.
Twelve pigs had systemic oxygen delivery (DO2) and consumption (VO2) measured before CPB and then underwent CPB at 35 degrees C. During CPB, measurements of DO2 and VO2 were obtained at an MAP of approximately 50 mmHg and a pump flow of 2.2 L/min/m2. Thereafter, MAP was elevated to 70 mmHg either by increases in pump flow or by a phenylephrine infusion, and the balance between systemic oxygen supply and demand was reassessed.
Before CPB, DO2 was 375 +/- 83 mL/min/m2 and decreased with the onset of CPB mainly because of the effects of hemodilution. During CPB, with a pump flow of 2.2 L/min/m2 and an MAP of 53 mmHg, DO2 was 218 +/- 40 mL/min/m2. Increasing perfusion pressure to an MAP of 72 mmHg with phenylephrine and maintaining pump flow constant (2.2 L/min/m2) did not change DO2 (222 +/- 37 mL/min/m2), and the oxygen extraction ratio (OER) was increased relative to pre-CPB levels. In contrast, increasing MAP to 71 mmHg by increasing pump flow to 3.2 L/min/m2 resulted in a significantly greater DO2, and the OER normalized to the pre-CPB value.
During CPB with conventional flow rates, DO2 is decreased. Supporting MAP with increases in pump flow better maintains DO2 than the administration of an alpha-agonist.
研究在体外循环（CPB）期间使用去氧肾上腺素输注和增加泵流量来维持平均动脉压（MAP）时，它们对全身氧供和氧需的影响。
前瞻性、非盲法研究。
梅奥基金会（明尼苏达州罗切斯特）的动物体外循环实验室。
12头猪。
12头猪在CPB前测量全身氧输送（DO2）和氧消耗（VO2），然后在35℃下进行CPB。在CPB期间，在MAP约为50 mmHg且泵流量为2.2 L/min/m²时测量DO2和VO2。此后，通过增加泵流量或去氧肾上腺素输注将MAP提高到70 mmHg，并重新评估全身氧供和氧需之间的平衡。
CPB前，DO2为375±83 mL/min/m²，CPB开始时DO2下降，主要是由于血液稀释的影响。CPB期间，泵流量为2.2 L/min/m²且MAP为53 mmHg时，DO2为218±40 mL/min/m²。使用去氧肾上腺素将灌注压提高到MAP为72 mmHg并保持泵流量恒定（2.2 L/min/m²）时，DO2未改变（222±37 mL/min/m²），且氧摄取率（OER）相对于CPB前水平升高。相比之下，将泵流量增加到3.2 L/min/m²使MAP提高到71 mmHg，导致DO2显著增加，且OER恢复到CPB前的值。
在常规流量的CPB期间，DO2降低。通过增加泵流量维持MAP比使用α受体激动剂能更好地维持DO2。
