Hoeksel S A, Blom J A, Jansen J R, Schreuder J J
Department of Anaesthesiology, Cardiovascular Research Institute Maastricht, University of Limburg, The Netherlands.
J Clin Monit. 1996 Sep;12(5):397-403. doi: 10.1007/BF02077637.
To develop an algorithm that corrects pulmonary artery pressure signals of ventilated patients for the respiration artifact. The algorithm should test the validity of the pulmonary pressure signal and differentiate between the cyclic respiration artifact and true measurement artifacts.
The shape of each pulmonary pressure beat is described by eight characteristic features, including mean pressure value and the systolic and diastolic timing and pressure values. The features are corrected for the respiration artifact by fitting them in a least-squares sense on the first and second harmonics of the ventilator frequency. The corrected features are used by a signal validation algorithm, which adds a validity flag to each pressure beat. The validation algorithm rejects pressure beats with sudden changes in their shape but adapts itself when the changes persist.
The performance of the correction and validation technique was evaluated using pulmonary artery pressure signals of 30 patients who were scheduled for open heart surgery. The algorithm correctly recognized as invalid data those pressure signals disturbed by coagulation, surgical manipulations, or flushes of the pressure line. The algorithm marked on average 77 +/- 11% of the pulmonary pressure beats as valid.
The validation algorithm marked sufficient pressure beats as valid to update a trend display every 5 sec. The correction algorithm enabled the validation algorithm to differentiate between true measurement artifacts and the respiration artifact.
开发一种算法，用于校正通气患者肺动脉压力信号中的呼吸伪影。该算法应测试肺动脉压力信号的有效性，并区分周期性呼吸伪影和真正的测量伪影。
每个肺动脉压力搏动的形状由八个特征描述，包括平均压力值、收缩期和舒张期的时间及压力值。通过在呼吸机频率的一次和二次谐波上进行最小二乘拟合，对这些特征进行呼吸伪影校正。信号验证算法使用校正后的特征，为每个压力搏动添加一个有效性标志。验证算法会拒绝形状突然变化的压力搏动，但在变化持续时会进行自我调整。
使用30例计划进行心脏直视手术患者的肺动脉压力信号，对校正和验证技术的性能进行了评估。该算法能正确识别受凝血、手术操作或压力管路冲洗干扰的无效压力信号。该算法平均将77±11%的肺动脉压力搏动标记为有效。
验证算法标记了足够数量的有效压力搏动，可每5秒更新一次趋势显示。校正算法使验证算法能够区分真正的测量伪影和呼吸伪影。
