OBJECTIVES: 

The aim of the current study was to investigate the level of cardiorespiratory fitness and neuromuscular function of ICU survivors after COVID-19 and to examine whether these outcomes are related to ICU stay/mechanical ventilation duration.

DESIGN: 

Prospective nonrandomized study.

SETTING: 

Patients hospitalized in ICU for COVID-19 infection.

PATIENTS: 

Sixty patients hospitalized in ICU (mean duration: 31.9 ± 18.2 d) were recruited 4–8 weeks post discharge from ICU.

INTERVENTIONS: 

None.

MEASUREMENTS AND MAIN RESULTS: 

Patients visited the laboratory on two separate occasions. The first visit was dedicated to quality of life questionnaire, cardiopulmonary exercise testing, whereas measurements of the knee extensors neuromuscular function were performed in the second visit. Maximal oxygen uptake (Vo₂max) was 18.3 ± 4.5 mL·min^–1·kg^-1, representing 49% ± 12% of predicted value, and was significantly correlated with ICU stay/mechanical ventilation (MV) duration (R = –0.337 to –0.446; p < 0.01 to 0.001), as were maximal voluntary contraction and electrically evoked peak twitch. Vo₂max (either predicted or in mL· min^–1·kg^-1) was also significantly correlated with key indices of pulmonary function such as predicted forced vital capacity or predicted forced expiratory volume in 1 second (R = 0.430–0.465; p ≤ 0.001) and neuromuscular function. Both cardiorespiratory fitness and neuromuscular function were correlated with self-reported physical functioning and general health status.

CONCLUSIONS: 

Vo₂max was on average only slightly above the 18 mL·min^–1·kg^-1, that is, the cut-off value known to induce difficulty in performing daily tasks. Overall, although low physical capacities at admission in ICU COVID-19 patients cannot be ruled out to explain the association between Vo₂max or neuromuscular function and ICU stay/MV duration, altered cardiorespiratory fitness and neuromuscular function observed in the present study may not be specific to COVID-19 disease but seem applicable to all ICU/MV patients of similar duration.

中文翻译：

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机械通气 ICU COVID-19 患者的心肺健康和神经肌肉功能*

目标： 

本研究的目的是调查 COVID-19 后 ICU 幸存者的心肺健康水平和神经肌肉功能，并检查这些结果是否与 ICU 停留/机械通气持续时间有关。

设计： 

前瞻性非随机研究。

环境： 

因 COVID-19 感染而在 ICU 住院的患者。

患者： 

在 ICU 出院后 4-8 周招募了 60 名在 ICU 住院的患者（平均持续时间：31.9 ± 18.2 天）。

干预措施： 

没有任何。

测量和主要结果： 

患者在两个不同的场合访问了实验室。第一次就诊专门针对生活质量问卷、心肺运动测试，而在第二次就诊时进行膝伸肌神经肌肉功能测量。最大摄氧量 (V o ₂ max) 为 18.3 ± 4.5 mL·min ^–1 ·kg ^-1，占预测值的 49% ± 12%，并且与 ICU 停留/机械通气 (MV) 持续时间显着相关（R = –0.337 至 –0.446；p < 0.01 至 0.001），最大自主收缩和电诱发峰值抽搐也是如此。V o ₂最大值（预测值或单位为 mL·min ^–1 ·kg ^-1) 也与肺功能的关键指标显着相关，例如预测的用力肺活量或预测的第 1 秒用力呼气量 ( R = 0.430–0.465；p ≤ 0.001) 和神经肌肉功能。心肺健康和神经肌肉功能都与自我报告的身体机能和一般健康状况相关。

结论： 

V o ₂ max 平均仅略高于 18 mL·min ^–1 ·kg ^-1，即已知会导致执行日常任务困难的临界值。总体而言，尽管不能排除 COVID-19 患者入 ICU 时体力低下可以解释最大摄氧量或神经肌肉功能与 ICU 停留时间/MV 持续时间之间的关联_，但本研究中观察到的心肺健康和神经肌肉功能改变可能无法解释特定于 COVID-19 疾病，但似乎适用于所有持续时间相似的 ICU/MV 患者。