应用新型组织二氧化碳监测技术进行围术期心肌缺血/再灌注检测。

Perioperative detection of myocardial ischaemia/reperfusion with a novel tissue CO2 monitoring technology.

机构信息

Division of Emergencies and Critical Care, Intervention Centre, Department of Clinical and Biomedical Engineering, Oslo University Hospital and University of Oslo, Norway.

出版信息

Eur J Cardiothorac Surg. 2012 Jul;42(1):157-63. doi: 10.1093/ejcts/ezr278. Epub 2012 Jan 20.

DOI:10.1093/ejcts/ezr278

PMID:22290904

Abstract

OBJECTIVES

Detection of perioperative myocardial ischaemia in cardiac surgery remains challenging, as current clinical bedside monitoring is insufficient in making proper diagnoses in real-time. Cellular metabolism gets altered during ischaemia and tissue PCO2 is produced in the course of buffering anaerobic lactic acidosis. Myocardial tissue PCO2 has been suggested as a parameter of ischaemia, but PCO2 measurement devices for routine clinical usage are lacking. Study aims were to (i) evaluate the diagnostic potential of PCO2 in early detection of localized myocardial metabolic changes, (ii) compare PCO2 obtained by novel conductometric PCO2 sensors (IscAlert) with fibre-optical sensors (Neurotrend), and (iii) investigate the relationship between myocardial PCO2, PO2 and parameters of energy consumption during regional myocardial ischaemia/reperfusion.

METHODS

In nine pigs, IscAlert sensors, Neurotrend sensors and microdialysis catheters were placed in the myocardium in the supply region of the left anterior descending (LAD) or circumflex (CX) coronary artery. LAD was occluded for 1, 3, 5 and 15 min, with 30 min of reperfusion between occlusion intervals. PCO2, PO2 and pH were measured continuously, microdialysis samples were obtained intermittently. The generation rate of CO2 (time-derivative of PCO2, TDPCO2) was calculated.

RESULTS

Myocardial ischaemia was confirmed by PO2 and pH decline, accompanied by lactate and lactate/pyruvate ratio increase. PCO2 measured by IscAlert increased significantly (P<0.01) during all occlusions and the increase was related to duration of ischaemia. PCO2 normalized during reperfusion. No significant changes were observed in CX region, indicating high regional sensitivity and specificity. Similar results were found with fibre-optically measured PCO2 and maximum PCO2 values during each interval correlated well with PCO2 values measured by IscAlert (R=0.93±0.05, P<0.001). Maximum TDPCO2 depicted beginning of anoxia and diminishing metabolism during anaerobic conditions.

CONCLUSIONS

IscAlert sensors enable reliable and continuous detection of myocardial ischaemia by measuring myocardial PCO2. A combination of PCO2 and TDPCO2 seems promising in revealing information about substrate supply and cellular homeostasis during ischaemic events.

摘要

目的

在心脏手术中，检测围术期心肌缺血仍然具有挑战性，因为当前的临床床边监测在实时做出正确诊断方面还不够充分。在缺血过程中，细胞代谢会发生改变，而在缓冲无氧乳酸酸中毒的过程中会产生组织 PCO2。心肌组织 PCO2 已被提议作为缺血的参数，但缺乏用于常规临床使用的 PCO2 测量设备。研究目的是：(i) 评估 PCO2 在早期检测局部心肌代谢变化中的诊断潜力；(ii) 比较新型电导式 PCO2 传感器（IscAlert）和光纤传感器（Neurotrend）获得的 PCO2；以及 (iii) 研究局部心肌缺血/再灌注期间心肌 PCO2、PO2 与能量消耗参数之间的关系。

方法

在 9 头猪中，将 IscAlert 传感器、Neurotrend 传感器和微透析导管放置在左前降支（LAD）或回旋支（CX）冠状动脉供血区的心肌中。LAD 闭塞 1、3、5 和 15 分钟，闭塞间隔之间有 30 分钟的再灌注。连续测量 PCO2、PO2 和 pH 值，间歇性采集微透析样本。计算 CO2 的生成速率（PCO2 的时间导数，TDPCO2）。

结果

通过 PO2 和 pH 值下降证实心肌缺血，同时伴有乳酸和乳酸/丙酮酸比值增加。IscAlert 测量的 PCO2 在所有闭塞期间均显著升高（P<0.01），且升高与缺血持续时间有关。再灌注期间 PCO2 恢复正常。CX 区域无明显变化，表明具有较高的区域敏感性和特异性。光纤测量的 PCO2 也得到了类似的结果，每个间隔的最大 PCO2 值与 IscAlert 测量的 PCO2 值相关性良好（R=0.93±0.05，P<0.001）。最大 TDPCO2 描绘了缺氧的开始和无氧条件下代谢的减少。