Data from: Smart bracelet to assess physical activity after cardiac surgery: a prospective study

Objectives: Little is known about the physical activity of
patients after cardiac surgery. This study was designed to assess this
activity using a connected bracelet.  Methods: In this
prospective, monocentric study, patients scheduled for cardiac surgery
were offered to wear an electronic bracelet. The main objective was to
measure the physical activity recovery. Secondary objectives were the
predictors of the correct use of the monitoring system, of the physical
recovery and, if any, the relationship between physical activity and
out-of-hospital morbidity.  Results: One hundred
patients were included. Most patients (86%) were interested in
participating in the study. The compliance to the device and to the study
protocol was good (94%). At discharge, the mean number of daily steps was
1454 ± 145 steps, increasing quite homogeneously, reaching 5801±1151 steps
at Day 60. The best fit regression curve gave a maximum number of steps at
5897±119 (r²=0.97). The 85% level of activity was achieved at Day
30±3.  No predictor of noncompliance was found. At
discharge, age was independently associated with a lower number of daily
steps (p <0.001). At Day 60, age, peripheral arterial disease and
cardio-pulmonary bypass duration were independently associated with a
lower number of daily steps (p=0.039, p=0.041 and p=0.033,
respectively).  Conclusions: After cardiac surgery,
wearing a smart bracelet recording daily steps is simple, well tolerated
and suitable for measuring physical activity. Standard patients achieved
around 6000 daily steps 2 months after discharge. 85% of this activity is
reached in the first month.

研究目标：目前针对心脏手术后患者的身体活动水平的相关研究仍较为有限。本研究旨在借助可穿戴连接手环（connected bracelet）评估该类患者的术后身体活动情况。

研究方法：本研究为一项单中心前瞻性研究，纳入拟接受心脏手术的患者，为其佩戴电子手环（electronic bracelet）开展监测。本研究的主要研究目标为评估患者的术后身体活动恢复情况；次要研究目标包括：明确监测系统正确使用的预测因素、身体功能恢复的预测因素，以及若存在相关关联，分析术后身体活动与院外发病情况之间的关系。

研究结果：本研究共纳入100例患者，其中86%的患者自愿参与本研究。受试者对研究设备及研究方案的依从性良好，依从率达94%。患者出院时的日均步行步数为1454±145步，该指标呈均匀上升趋势，至术后第60天时升至5801±1151步。经最优拟合回归曲线计算，患者日均步行步数的峰值为5897±119步（决定系数r²=0.97）。患者在术后第30±3天时即可达到目标活动量的85%。未发现与设备使用不依从相关的预测因素。患者出院时，年龄为日均步行步数较低的独立相关因素（P<0.001）；至术后第60天时，年龄、外周动脉疾病（peripheral arterial disease）及体外循环（cardio-pulmonary bypass）时长均为日均步行步数较低的独立相关因素（分别对应P=0.039、P=0.041及P=0.033）。

研究结论：心脏手术后佩戴可记录日均步行步数的智能手环（smart bracelet）操作简便、耐受性良好，且适用于术后身体活动水平的监测。常规患者在出院后2个月时，日均步行步数可达6000步左右，其目标活动量的85%可在术后第一个月内达成。