Association Between Postoperative Long-Term Heart Rate Variability and Postoperative Delirium in Elderly Patients Undergoing Orthopedic Surgery: A Prospective Cohort Study.

Jiaduo Sun,Mengjiao He,Qibo Liang,Ping Xu,Qingguo Zhang,Shiyuan Xu,Yimin Pang,Dongdong Que,Zhibin Huang,Baojia Lin

doi:10.3389/fnagi.2021.646253

Jiaduo Sun, Mengjiao He + Show 8 more

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https://doi.org/10.3389/fnagi.2021.646253

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Abstract

BackgroundPostoperative delirium (POD) is a common complication after orthopedic surgery in elderly patients. The elderly may experience drastic changes in autonomic nervous system (ANS) activity and circadian rhythm disorders after surgery. Therefore, we intend to explore the relationship between postoperative long-term heart rate (HR) variability (HRV), as a measure of ANS activity and circadian rhythm, and occurrence of POD in elderly patients.MethodsThe study population of this cohort was elderly patients over 60 years of age who scheduled for orthopedic surgery under spinal anesthesia. Patients were screened for inclusion and exclusion criteria before surgery. Then, participants were invited to wear a Holter monitor on the first postoperative day to collect 24-h electrocardiographic (ECG) data. Parameters in the time domain [the standard deviation of the normal-to-normal (NN) intervals (SDNN), mean of the standard deviations of all the NN intervals for each 5-min segment of a 24-h HRV recording (SDNNI), and the root mean square of successive differences of the NN intervals (RMSSD)] and frequency domain [heart rate (HR), high frequency (HF), low frequency (LF), very low frequency (VLF), ultra low frequency (ULF), and total power (TP)] were calculated. Assessment of delirium was performed daily up to the seventh postoperative day using the Chinese version of the 3-Min Diagnostic Interview for CAM-defined Delirium (3D-CAM). The relationship between HRV and POD, as well as the association between HRV and duration of POD, was assessed.ResultsOf the 294 cases that finally completed the follow-up, 60 cases developed POD. Among the HRV parameters, SDNNI, VLF, and ULF were related to the occurrence of POD. After adjustment for potential confounders, the correlation between HRV indices and POD disappeared. Through stratified analysis, two significant negative correlations emerged: ULF in young-old participants and SDNNI, VLF, and ULF in male patients.ConclusionThe lower HRV parameters may be related to the occurrence of POD, and this correlation is more significant in young-old and male patients. ANS disorders and rhythm abnormalities reflected by HRV changes may represent a possible mechanism that promotes POD.

Highlights

Delirium is a neurocognitive disorder characterized by a disturbance in attention, level of consciousness, and cognition, in which symptoms are acute in onset and may fluctuate in severity throughout the day (Battle, 2013)
We enrolled patients aged 60 or older who scheduled for orthopedic surgery [including total hip arthroplasty (THA), total knee arthroplasty (TKA), revision TKA (RTKA), revision THA (RTHA), hip fracture repair, and femoral shaft fracture (FSF) surgery] under spinal anesthesia
We observed a connection between HRV indices and Postoperative delirium (POD), which may be more pronounced in young-old patients

Summary

Introduction

Delirium is a neurocognitive disorder characterized by a disturbance in attention, level of consciousness, and cognition, in which symptoms are acute in onset and may fluctuate in severity throughout the day (Battle, 2013). As is proved acting in many mental disorders (Kim et al, 2018; Mulcahy et al, 2019), alterations in autonomic nervous system (ANS) activity have been suggested to be related to delirium (Maclullich et al, 2008). Circadian rhythm that is regulated by the complex interaction between the central nervous system (CNS) and the ANS has been demonstrated to be related to POD (Maldonado, 2018; Riganello et al, 2019a,b). Postoperative delirium (POD) is a common complication after orthopedic surgery in elderly patients. The elderly may experience drastic changes in autonomic nervous system (ANS) activity and circadian rhythm disorders after surgery. We intend to explore the relationship between postoperative long-term heart rate (HR) variability (HRV), as a measure of ANS activity and circadian rhythm, and occurrence of POD in elderly patients

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