Department of Anaesthesiology, University Hospital of the RWTH Aachen, Pauwelsstr. 30, D-52074 Aachen, Germany.
Br J Anaesth. 2011 Jun;106(6):776-84. doi: 10.1093/bja/aer066. Epub 2011 Mar 25.
Arterial pressure waveform analysis of cardiac output (APCO) without external calibration (FloTrac/Vigileo™) is critically dependent upon computation of vascular tone that has necessitated several refinements of the underlying software algorithms. We hypothesized that changes in vascular tone induced by high-dose vasopressor therapy affect the accuracy of APCO measurements independently of the FloTrac software version.
In this prospective observational study, we assessed the validity of uncalibrated APCO measurements compared with transpulmonary thermodilution cardiac output (TPCO) measurements in 24 patients undergoing vasopressor therapy for the treatment of cerebral vasospasm after subarachnoid haemorrhage.
Patients received vasoactive support with [mean (sd)] 0.53 (0.46) µg kg(-1) min(-1) norepinephrine resulting in mean arterial pressure of 104 (14) mm Hg and mean systemic vascular resistance of 943 (248) dyn s(-1) cm(-5). Cardiac output (CO) data pairs (158) were obtained simultaneously by APCO and TPCO measurements. TPCO ranged from 5.2 to 14.3 litre min(-1), and APCO from 4.1 to 13.7 litre min(-1). Bias and limits of agreement were 0.9 and 2.5 litre min(-1), resulting in an overall percentage error of 29.6% for 68 data pairs analysed with the second-generation FloTrac(®) software and 27.9% for 90 data pairs analysed with the third-generation software. Precision of the reference technique was 2.6%, while APCO measurements yielded a precision of 29.5% and 27.9% for the second- and the third-generation software, respectively. For both software versions, bias (TPCO-APCO) correlated inversely with systemic vascular resistance.
In neurosurgical patients requiring high-dose vasopressor support, precision of uncalibrated CO measurements depended on systemic vascular resistance. Introduction of the third software algorithm did not improve the insufficient precision (>20%) for APCO measurements observed with the second software version.
无外部校准的心输出量动脉压波形分析（APCO）（FloTrac/Vigileo™）严重依赖于血管张力的计算，这需要对基础软件算法进行多次改进。我们假设，高剂量血管加压剂治疗引起的血管张力变化会独立于 FloTrac 软件版本影响 APCO 测量的准确性。
在这项前瞻性观察研究中，我们评估了未经校准的 APCO 测量与经肺温度稀释心输出量（TPCO）测量在 24 例蛛网膜下腔出血后接受血管加压剂治疗以治疗脑血管痉挛的患者中的相关性。
患者接受了 [平均（标准差）] 0.53（0.46）µg kg(-1) min(-1) 去甲肾上腺素的血管活性支持，导致平均动脉压为 104（14）mmHg 和平均全身血管阻力为 943（248）dyn s(-1) cm(-5)。APCO 和 TPCO 同时测量获得 158 对心输出量（CO）数据。TPCO 范围为 5.2 至 14.3 升/分钟，APCO 范围为 4.1 至 13.7 升/分钟。偏差和一致性界限分别为 2.5 升/分钟和 0.9 升/分钟，导致第二代 FloTrac(®)软件分析的 68 对数据的总百分比误差为 29.6%，第三代软件分析的 90 对数据的总百分比误差为 27.9%。参考技术的精度为 2.6%，而 APCO 测量的第二代和第三代软件的精度分别为 29.5%和 27.9%。对于这两个软件版本，偏差（TPCO-APCO）与全身血管阻力呈反比相关。
在需要高剂量血管加压剂支持的神经外科患者中，未经校准的 CO 测量精度取决于全身血管阻力。第三代软件算法的引入并没有改善第二代软件版本观察到的 APCO 测量精度不足（>20%）。
