Brain oxygen monitoring: in-vitro accuracy, long-term drift and response-time of Licox- and Neurotrend sensors
Brain oxygen monitoring: in-vitro accuracy, long-term drift and response-time of Licox- and Neurotrend sensors
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DOI：
10.1007/s00701-005-0512-8
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发表时间：
2005-07-01
影响因子：
2.4
通讯作者：
Kempski, O
中科院分区：
文献类型：
--
作者：
Hoelper, BM;Alessandri, B;Kempski, O
背景氧张力传感器已被用于监测人脑中的组织氧合数年。最常用的传感器Licox（LX）和Neurotrend（NT）的工作原理不同，它们从未被独立验证过体外正确测量。因此，我们试图澄清，如果两个目前可用的传感器提供足够的准确性和稳定性。将12个LX氧张力传感器和NT传感器放置在液体填充的眼压计室中。将溶液保持在37 +/- 0.2 ℃，并用含有不同O-2-和CO2-浓度的五种校准气体平衡。平衡后，读取每种气体浓度的读数（准确度测试）。然后，将传感器置于3%O-2和9%CO2中，并在24、48、72、96和120小时后读取读数（漂移测试）。此后，使用预平衡的眼压计进行90%响应时间测试，将传感器从1%氧气浓度转移到5%氧气浓度并返回。本研究使用了所有Licox氧探头[ 12]。14个Neurotrend传感器中有2个未校准，显示NT的故障率为14%。准确度测试期间的氧分压测量如下：1% O2（7.1 mmHg）：LX 6.5 +/- 0.4，NT 5.3 +/- 2.3 mmHg，2% O-2（14.2 mmHg）：LX 12.9 +/- 0.6，NT 12.1 +/- 2.2 mmHg，3% O-2（21.4 mmHg）：LX 19.8 +/- 0.7，NT 19.4 +/- 2.4 mmHg，5% O-2（35.8 mmHg）：LX 33.4 +/- 1.0 mmHg，NT 33.5 +/- 2.9 mmHg，8% O-2（57.0 mmHg）：53.8 +/- 1.5，NT 53.6 +/- 3.3 mmHg。在3% O-2（21 mmHg）中120小时后，测得LX为19.8 +/- 1.9 mmHg，NT为17.9 +/- 4.7 mmHg。从1%到5%/5%到1%氧气浓度的90%响应时间为LX 129 +/- 27/174 +/- 26秒，NT 55 +/- 19/98 +/- 39秒。这两种系统都能充分测量氧分压，但LX探头更准确。NT传感器在1%O-2中读取的pO（2）显著较低，并且随着氧浓度的升高而显示出增加的偏差，这是由于十二个探针中的两个。两种传感器的氧分压读数略微向较低方向漂移，但NT更明显，这不会影响长期使用。NT非常准确地测量pCO（2）和pH。
Background. Oxygen tension sensors have been used to monitor tissue oxygenation in human brain for several years. The working principals of the most frequently used sensors, the Licox (LX) and Neurotrend (NT), are different, and they have never been validated independently for correct measurement in vitro. Therefore, we tried to clarify if the two currently available sensors provide sufficient accuracy and stability.Method. 12 LX oxygen tension sensors and NT sensors were placed into a liquid-filled tonometer chamber. The solution was kept at 37 +/- 0.2 degrees C and equilibrated with five calibration gases containing different O-2- and CO2-concentrations. After equilibration, readings were taken for each gas concentration ( accuracy test). Afterwards, the sensors were left in 3% O-2 and 9% CO2 and readings were taken after 24, 48, 72, 96 and 120 hours ( drift test). Thereafter, a 90% response time test was performed transferring sensors from 1% to 5% oxygen concentration and back, using pre-equilibrated tonometers.Findings. All Licox oxygen probes [ 12] were used for this study. Two of 14 Neurotrend sensors did not calibrate, revealing a failure rate of 14% for NT. Oxygen tension during the accuracy test was measured as follows: 1% O2 ( 7.1 mmHg): LX 6.5 +/- 0.4, NT 5.3 +/- 2.3 mmHg, 2% O-2 (14.2 mmHg): LX 12.9 +/- 0.6, NT 12.1 +/- 2.2 mmHg, 3% O-2 (21.4 mmHg): LX 19.8 +/- 0.7, NT 19.4 +/- 2.4 mmHg, 5% O-2 (35.8 mmHg): LX 33.4 +/- 1.0 mmHg, NT 33.5 +/- 2.9 mmHg, 8% O-2 (57.0 mmHg): 53.8 +/- 1.5, NT 53.6 +/- 3.3 mmHg. After 120 hours in 3% O-2 (21 mmHg), LX measured 19.8 +/- 1.9 mmHg, NT 17.9 +/- 4.7 mmHg. 90% response time from 1% to 5%/5% to 1% oxygen concentration was 129 +/- 27/174 +/- 26 sec for LX, 55 +/- 19/98 +/- 39 sec for NT.Conclusions. Both systems are measuring oxygen tension sufficiently, but more accurately with LX probes. NT sensors read significantly lower pO(2) in 1% O-2 and show an increasing deviation with higher oxygen concentrations which was due to two of twelve probes. A slight drift towards lower oxygen tension readings for both sensors but more pronounced for the NT does not impair long-term use. NT measures pCO(2) and pH very accurately.