Department of Paediatric Anaesthesia and Intensive Care, SU/The Queen Silvia Children's Hospital, Gothenburg, Sweden.
J Clin Monit Comput. 2009 Dec;23(6):355-61. doi: 10.1007/s10877-009-9203-y. Epub 2009 Oct 10.
For paediatric monitoring and demanding applications such as metabolic monitoring and measurements of functional residual capacity combining gas concentration with flow/volume measurements the performance of side-stream monitors (SSGM) is suboptimal. The objective was to evaluate the performance of a miniaturised mainstream multigas monitor (MSGM) alleged to offer fast response gas monitoring. The MSGM uses infrared technique for measurements of carbon dioxide, nitrous oxide and inhalation agents and fuel cell technique for oxygen monitoring. The MSGM performance was com- pared to a state of the art side-stream monitor in a bench study.
Response time was measured in two bench study set ups; a high flow oxygen flush to achieve one step change in gas concentrations and during continuous ventilation using a circuit with an oxygen consuming/carbon dioxide producing lung model connected to a ventilator. Averaged tracings from the tested monitors were used for calculation of the 90-10% decline of CO(2), the corresponding 10-90% incline of O(2) and N(2)O and of Isoflurane concentrations in the flush set up and at different inspired O(2) for the O(2) upslope and corresponding CO(2) down- slope during continuous ventilation at different breathing frequencies. Calibration gases with different concentrations of CO(2), O(2) and N(2)O were used for testing of accuracy.
The MSGM response time for CO(2) was 96 (88-100) compared to 348 (340-352) ms for the SSGM (P < 0.001). Corresponding response times for O(2) was 108 (76-144), and 432 (360-448) ms (P < 0.001), respectively. At a respiratory rate of 60 BPM the SSGM trace was damped and sinusoidal whereas the MSGM displayed wider amplitude and a square waveform. The deviations from calibration gas values were within clinically acceptable range and linear for all gases over the concentration range studied for both monitors.
The MSGM response time for CO(2) and O(2) was less than 1/3 of the SSGM. The performance of the MSGM was maintained at high breathing frequencies. The accuracy was within clinically acceptable limits for both monitors.
对于儿科监测和代谢监测等要求苛刻的应用，以及功能残气量的测量，与流量/体积测量相结合的旁流监测器（SSGM）的性能并不理想。目的是评估一种声称具有快速响应气体监测功能的微型主流多气体监测器（MSGM）的性能。MSGM 采用红外线技术测量二氧化碳、氧化亚氮和吸入剂，采用燃料电池技术测量氧气。在一项台架研究中，将 MSGM 的性能与最先进的旁流监测器进行了比较。
在两个台架研究设置中测量响应时间；一种是高流量氧气冲洗，以实现气体浓度的一步变化，另一种是在一个带有耗氧/产二氧化碳肺模型的回路中连续通气，该模型连接到呼吸机。使用测试监测器的平均轨迹来计算冲洗设置中 CO(2) 的 90-10%下降、相应的 O(2) 和 N(2)O 的 10-90%上升以及 Isoflurane 浓度，以及在不同呼吸频率下连续通气时不同吸入 O(2) 时的 O(2) 上坡和相应的 CO(2) 下坡。使用不同浓度的 CO(2)、O(2) 和 N(2)O 的校准气体来测试准确性。
MSGM 对 CO(2) 的响应时间为 96（88-100）ms，而 SSGM 为 348（340-352）ms（P<0.001）。相应的 O(2) 的响应时间分别为 108（76-144）ms 和 432（360-448）ms（P<0.001）。在呼吸频率为 60 BPM 时，SSGM 轨迹被阻尼并呈正弦波，而 MSGM 则显示出更宽的振幅和方波。两种监测器的所有气体在研究浓度范围内的校准气体值偏差均在临床可接受范围内，且呈线性关系。
MSGM 对 CO(2) 和 O(2) 的响应时间不到 SSGM 的 1/3。MSGM 的性能在高呼吸频率下得以维持。两种监测器的准确性均在临床可接受范围内。
