20028 VA Boston Healthcare System, Massachusetts, USA.
Harvard Medical School, Boston, Massachusetts, USA.
Hum Factors. 2021 Aug;63(5):757-771. doi: 10.1177/0018720820976297. Epub 2020 Dec 16.
This novel preliminary study sought to capture dynamic changes in heart rate variability (HRV) as a proxy for cognitive workload among perfusionists while operating the cardiopulmonary bypass (CPB) pump during real-life cardiac surgery.
Estimations of operators' cognitive workload states in naturalistic settings have been derived using noninvasive psychophysiological measures. Effective CPB pump operation by perfusionists is critical in maintaining the patient's homeostasis during open-heart surgery. Investigation into dynamic cognitive workload fluctuations, and their relationship with performance, is lacking in the literature.
HRV and self-reported cognitive workload were collected from three Board-certified cardiac perfusionists ( = 23 cases). Five HRV components were analyzed in consecutive nonoverlapping 1-min windows from skin incision through sternal closure. Cases were annotated according to predetermined phases: prebypass, three phases during bypass, and postbypass. Values from all 1min time windows within each phase were averaged.
Cognitive workload was at its highest during the time between initiating bypass and clamping the aorta (preclamp phase during bypass), and decreased over the course of the bypass period.
We identified dynamic, temporal fluctuations in HRV among perfusionists during cardiac surgery corresponding to subjective reports of cognitive workload. Not only does cognitive workload differ for perfusionists during bypass compared with pre- and postbypass phases, but differences in HRV were also detected within the three bypass phases.
These preliminary findings suggest the preclamp phase of CPB pump interaction corresponds to higher cognitive workload, which may point to an area warranting further exploration using passive measurement.
本初步研究旨在通过监测心肺转流（CPB）泵操作期间的心率变异性（HRV）来评估灌注师的认知工作负荷变化，以此作为在真实心脏手术中操作 CPB 泵的替代指标。
在自然环境中，使用非侵入性心理生理测量来评估操作人员的认知工作负荷状态。灌注师有效操作 CPB 泵对于维持患者在心脏直视手术期间的体内平衡至关重要。文献中缺乏对动态认知工作负荷波动及其与性能关系的研究。
从三名经过董事会认证的心脏灌注师（=23 例）中收集 HRV 和自我报告的认知工作负荷数据。从皮肤切口到胸骨关闭，连续 1 分钟非重叠窗口分析 5 个 HRV 成分。根据预定阶段对病例进行注释：体外循环前、体外循环期间的三个阶段和体外循环后。每个阶段内所有 1 分钟时间窗口的值的平均值。
认知工作负荷在开始体外循环和夹闭主动脉（体外循环前夹阶段）之间达到最高，并在体外循环期间逐渐降低。
我们在心脏手术期间发现了灌注师的 HRV 存在动态、时间波动，与主观认知工作负荷报告相对应。与体外循环前和体外循环后阶段相比，灌注师在体外循环期间的认知工作负荷不同，而且在三个体外循环阶段内也检测到了 HRV 差异。
这些初步发现表明 CPB 泵交互的前夹阶段对应更高的认知工作负荷，这可能表明需要进一步探索使用被动测量的区域。
