Brennan E G, O'Hare N J
Department of Medical Physics and Bioengineering, St James's Hospital, Dublin, Ireland.
Physiol Meas. 1998 Aug;19(3):405-12. doi: 10.1088/0967-3334/19/3/009.
A concise set of experiments is described which detail the calibration of a fluid-filled catheter-transducer system and the assessment of a widely used industrial algorithm for determining end-diastolic pressures using that system. First, the static response of the catheter-transducer system was evaluated in vitro by inserting the catheter into a graduated cylinder of saline. Twelve observations revealed a systematic undervaluation of pressure by the system of 1.78 mmHg with 95% limits of agreement ranging from -6.22 to 2.66 mmHg. Next, the dynamic response was evaluated in vivo by performing a transient step-response test. The system had an adequate dynamic response (fn = 11.12 Hz) for intraventricular pressure waveform replication but was considerably underdamped (beta = 0.16). Finally, the ability of the analysis software to detect the point of end-diastole and evaluate end-diastolic pressure was assessed by comparing system output with manual measurements of end-diastolic pressure in 12 patients. The mean difference between manually determined end-diastolic pressure and system output was 0.83 +/- 1.68 mm Hg. This difference is clinically insignificant and shows that the more noteworthy source of error is in the manometer-transducer emphasizing the importance of calibration and quality assurance of fluid-filled catheter-transducer systems for use in clinical cardiology or research.
本文描述了一组简洁的实验，详细介绍了充液导管 - 换能器系统的校准，以及使用该系统评估一种广泛应用的工业算法来确定舒张末期压力的情况。首先，通过将导管插入装有生理盐水的量筒中，在体外评估导管 - 换能器系统的静态响应。十二次观察结果显示，该系统对压力的评估存在系统性低估，低估幅度为1.78 mmHg，95%的一致性界限范围为 -6.22至2.66 mmHg。接下来，通过进行瞬态阶跃响应测试在体内评估动态响应。该系统对于心室内压力波形复制具有足够的动态响应（固有频率fn = 11.12 Hz），但阻尼明显不足（阻尼比beta = 0.16）。最后，通过比较系统输出与12例患者舒张末期压力的手动测量值，评估分析软件检测舒张末期点和评估舒张末期压力的能力。手动测定的舒张末期压力与系统输出之间的平均差异为0.83 +/- 1.68 mmHg。这种差异在临床上无显著意义，表明更值得注意的误差来源在于压力计 - 换能器，这凸显了用于临床心脏病学或研究的充液导管 - 换能器系统校准和质量保证的重要性。
