A self-calibrating telemetry system for measurement of ventricular pressure-volume relations in conscious, freely moving rats
A self-calibrating telemetry system for measurement of ventricular pressure-volume relations in conscious, freely moving rats
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DOI：
10.1152/ajpheart.00035.2004
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发表时间：
2004-12-01
影响因子：
4.8
通讯作者：
Sunagawa, K
中科院分区：
文献类型：
--
作者：
Uemura, K;Kawada, T;Sunagawa, K
利用蓝牙无线技术，我们开发了一种植入式遥测系统，用于测量清醒、自由活动大鼠的左心室压力-容积关系。遥测系统由连接到小型（14 g）完全植入式信号发射器的压力传导导管（1.8 Fr）组成。为了使该系统完全遥测，还进行了血液电阻率和并联电导率等遥测校准。为了估计血液电阻率，我们在压力传导导管上使用了四个间隔0.2 mm的电极。为了估计并联电导，我们使用双频方法。我们检查了校准的准确性、每搏输出量（SV）测量值和遥测的再现性。遥测法测得的血液电阻率与体外比色皿法测得的血液电阻率一致（y = 1.09x - 11.9，r（2）= 0.88，n = 10）。双频（2和20 kHz）法测得的平行电导与常规盐水注射法测得的平行电导相关良好（y = 1.59x - 1.77，r（2）= 0.87，n = 13）。下腔静脉阻塞时遥测SV与流量SV密切相关（y = 0.96x + 7.5，r（2）= 0.96，n = 4）。在6只清醒大鼠中，不同日期（平均间隔3天）重复遥测之间的差异相当小：舒张末期容积为13%，收缩末期容积为20%，舒张末期压为28%，收缩末期压为6%。我们的结论是，开发的遥测系统，使我们能够估计压力-容积的关系，合理的准确性和再现性在有意识的，untethered大鼠。
Using Bluetooth wireless technology, we developed an implantable telemetry system for measurement of the left ventricular pressure-volume relation in conscious, freely moving rats. The telemetry system consisted of a pressure-conductance catheter (1.8-Fr) connected to a small (14-g) fully implantable signal transmitter. To make the system fully telemetric, calibrations such as blood resistivity and parallel conductance were also conducted telemetrically. To estimate blood resistivity, we used four electrodes arranged 0.2 mm apart on the pressure-conductance catheter. To estimate parallel conductance, we used a dual-frequency method. We examined the accuracy of calibrations, stroke volume (SV) measurements, and the reproducibility of the telemetry. The blood resistivity estimated telemetrically agreed with that measured using an ex vivo cuvette method (y = 1.09x - 11.9, r(2) = 0.88, n = 10). Parallel conductance estimated by the dual-frequency (2 and 20 kHz) method correlated well with that measured by a conventional saline injection method (y = 1.59x - 1.77, r(2) = 0.87, n = 13). The telemetric SV closely correlated with the flowmetric SV during inferior vena cava occlusions (y = 0.96x + 7.5, r(2) = 0.96, n = 4). In six conscious rats, differences between the repeated telemetries on different days ( 3 days apart on average) were reasonably small: 13% for end-diastolic volume, 20% for end-systolic volume, 28% for end-diastolic pressure, and 6% for end-systolic pressure. We conclude that the developed telemetry system enables us to estimate the pressure-volume relation with reasonable accuracy and reproducibility in conscious, untethered rats.