Vital signs and impaired cognition in older emergency department patients: The APOP study

Background/Objectives
Cognitive impairment is a frequent problem among older patients attending the Emergency Department (ED) and can be the result of pre-existing cognitive impairment, delirium, or neurologic disorders. Another cause can also be acute disturbance of brain perfusion and oxygenation, which may be reversed by optimal resuscitation. This study aimed to assess the relationship between vital signs, as a measure of acute hemodynamic changes, and cognitive impairment in older ED patients.
Design
Prospective cohort study
Setting
ED’s of two tertiary care and two secondary care hospitals in the Netherlands.
Participants
2629 patients aged 70-years and older
Measurements
Vital signs were measured at the moment of ED arrival as part of routine clinical care. Cognition was measured using the Six-Item Cognitive Impairment Test (6-CIT).
Results
The median age of patients was 78 years (IQR 74–84). Cognitive impairment was present in 738 patients (28.1%). When comparing lowest with highest quartiles, a systolic blood pressure of <129 mmHg (OR 1.30, 95% confidence interval (95%CI) 0.98–1.73)was associated with increased risk of cognitive impairment. A higher respiratory rate (>21/min) was associated with increased risk of impaired cognition (OR 2.16, 95% CI 1.58–2.95) as well as oxygen saturation of <95% (OR 1.64, 95%CI 1.24–2.19).
Conclusion
Abnormal vital signs associated with decreased brain perfusion and oxygenation are also associated with cognitive impairment in older ED patients. This may partially be explained by the association between disease severity and delirium, but also by acute disturbance of brain perfusion and oxygenation. Future studies should establish whether normalization of vital signs will also acutely improve cognition.

背景与研究目标
急诊室（Emergency Department, ED）老年患者中，认知障碍是一类高发问题，其诱因涵盖既往认知障碍、谵妄或神经系统疾病，亦可由脑灌注与氧合的急性紊乱引发，此类紊乱可通过规范复苏实现逆转。本研究旨在评估作为急性血流动力学变化指标的生命体征，与老年急诊患者认知障碍之间的关联。
研究设计
前瞻性队列研究
研究地点
荷兰两家三级医疗医院与两家二级医疗医院的急诊室。
研究对象
2629名70岁及以上的患者。
测量方法
于患者抵达急诊室时测量生命体征，此为常规临床护理的组成部分；采用六条目认知障碍测试（Six-Item Cognitive Impairment Test, 6-CIT）评估认知功能。
研究结果
患者的中位年龄为78岁（四分位距74~84），其中738名患者存在认知障碍，占比28.1%。将最低四分位数组与最高四分位数组进行对比，结果显示收缩压<129mmHg（比值比OR=1.30，95%置信区间95%CI：0.98~1.73）与认知障碍风险升高相关；呼吸频率>21次/分（OR=2.16，95%CI：1.58~2.95）以及血氧饱和度<95%（OR=1.64，95%CI：1.24~2.19），均与认知功能受损风险升高存在显著关联。
研究结论
与脑灌注及氧合降低相关的异常生命体征，同样与老年急诊患者的认知障碍相关。该关联可部分归因于疾病严重程度与谵妄之间的联系，同时也与脑灌注和氧合的急性紊乱有关。未来研究应明确，生命体征恢复正常是否也能快速改善患者的认知功能。