Sydzyik R T, Stammers A H, Zavadil D P, Deptula J J, Christensen K A
Division of Clinical Perfusion Education, University of Nebraska Medical Center, Omaha 68198-5155, USA.
J Extra Corpor Technol. 1997 Sep;29(3):145-53.
The delivery of cardioplegia has traditionally been constrained by the physical limitations of the mechanical devices in use, yet myocardial protective strategies may vary both according to patient condition and operative requirements. The need for a cardioplegia administration device that allows flexibility and safety is evident. The purpose of this study was to evaluate the performance of the Quest Myocardial Protection System (MPS) during clinically simulated conditions. The MPS was evaluated in an in vitro setting under the following conditions: blood to crystalloid ratios (1:1, 4:1, 8:1, all blood), potassium concentrations ([K+]) of 10 and 25 mmol/L, calcium concentrations ([Ca++]) of 1.4 and 2.8 mmol/L, and at flow rates of 100 and 300 ml/min. Predicted values from the MPS were compared with measured values, with statistically significance accepted at p < .05 level. Significant differences were seen between measured and MPS cardioplegia delivery volumes at the 4:1, 8:1 and all blood ratios with a flow rate of 300 ml/min. There were no significant differences seen between measured and expected [K+] and [Ca++] delivery values across all combination of flow rates and ratios. Differences between delivery pressures of the MPS and measured values for flow rates of 100, 250 and 500 ml/min were 0.4, 1.2 and 7.6 mmHg respectively. The mean cardioplegia cooling time from 37 degrees C to 9 degrees C was 37 +/- 4.5 seconds, while rewarming from 7 degrees C to 37 degrees C, took 53 +/- 10.4 seconds. In conclusion, the Myocardial Protection System performance characteristics were precise in ratio delivery, concentrations of potassium agents, additive agent concentration, temperature, and pressure across all experimental conditions, with the exception of delivery volume.
传统上，心脏停搏液的输注受到所用机械设备物理限制的约束，然而心肌保护策略可能会因患者病情和手术要求而有所不同。显然需要一种具有灵活性和安全性的心脏停搏液给药装置。本研究的目的是评估在临床模拟条件下Quest心肌保护系统（MPS）的性能。在体外环境中，在以下条件下对MPS进行了评估：血晶比（1:1、4:1、8:1，全血）、钾浓度（[K+]）为10和25 mmol/L、钙浓度（[Ca++]）为1.4和2.8 mmol/L，以及流速为100和300 ml/min。将MPS的预测值与测量值进行比较，p < 0.05水平具有统计学意义。在流速为300 ml/min时，4:1、8:1和全血比例下，测量的心脏停搏液输送量与MPS之间存在显著差异。在所有流速和比例组合中，测量的和预期的[K+]及[Ca++]输送值之间没有显著差异。MPS的输送压力与流速为100、250和500 ml/min时的测量值之间的差异分别为0.4、1.2和7.6 mmHg。心脏停搏液从37摄氏度冷却到9摄氏度的平均时间为37 ± 4.5秒，而从7摄氏度复温到37摄氏度则需要53 ± 10.4秒。总之，除输送量外，心肌保护系统在所有实验条件下的比例输送、钾剂浓度、添加剂浓度、温度和压力方面的性能特征都很精确。
