Purpose Nosocomial infection contributes to adverse outcome after brain injury. This study investigates whether autonomic nervous system activity is associated with a decreased host immune response in patients following stroke or traumatic brain injury (TBI). Methods A prospective study was performed in adult patients with TBI or stroke who were admitted to the Intensive Care Unit of our tertiary university hospital between 2013 and 2016. Heart rate variability (HRV) was recorded daily and assessed for autonomic nervous system activity. Outcomes were nosocomial infections and immunosuppression, which was assessed ex vivo using whole blood stimulations with plasma of patients with infections, matched non-infected patients and healthy controls. Results Out of 64 brain injured patients, 23 (36%) developed an infection during their hospital stay. The ability of brain injured patients to generate a host response to the bacterial endotoxin lipopolysaccharides (LPS) was diminished compared to healthy controls ( p < 0.001). Patients who developed an infection yielded significantly lower TNF-α values (86 vs 192 pg/mL, p = 0.030) and a trend towards higher IL-10 values (122 vs 84 pg/mL, p = 0.071) following ex vivo whole blood stimulations when compared to patients not developing an infection. This decreased host immune response was associated with altered admission HRV values. Brain injured patients who developed an infection showed increased normalized high-frequency power compared to patients not developing an infection (0.54 vs 0.36, p = 0.033), whereas normalized low-frequency power was lower in infected patients (0.46 vs 0.64, p = 0.033). Conclusion Brain injured patients developing a nosocomial infection show parasympathetic predominance in the acute phase following brain injury, reflected by alterations in HRV, which parallels a decreased ability to generate an immune response to stimulation with LPS.

中文翻译：

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脑损伤危重患者自主神经系统活动与院内感染风险

目的医院感染会导致脑损伤后的不良后果。这项研究调查了自主神经系统活动是否与中风或创伤性脑损伤 (TBI) 后患者的宿主免疫反应降低有关。方法 对 2013 年至 2016 年期间入住我校三级大学医院重症监护室的成年 TBI 或卒中患者进行前瞻性研究。每天记录心率变异性 (HRV) 并评估自主神经系统活动。结果是医院感染和免疫抑制，使用全血刺激感染患者的血浆、匹配的未感染患者和健康对照进行体外评估。结果 在 64 名脑损伤患者中，23 名 (36%) 在住院期间发生感染。与健康对照相比，脑损伤患者对细菌内毒素脂多糖 (LPS) 产生宿主反应的能力减弱 (p < 0.001)。发生感染的患者在体外全血后产生显着较低的 TNF-α 值（86 对 192 pg/mL，p = 0.030）和更高 IL-10 值（122 对 84 pg/mL，p = 0.071）与未发生感染的患者相比。这种降低的宿主免疫反应与入院 HRV 值的改变有关。与未发生感染的患者相比，发生感染的脑损伤患者的标准化高频功率增加（0.54 对 0.36，p = 0.033），而感染患者的标准化低频功率较低（0.46 对 0.64，p = 0.033 ）。