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Is delirium a specific complication of viral acute respiratory distress syndrome?
Critical Care volume 24, Article number: 401 (2020)
Acute respiratory distress syndrome (ARDS) caused by the novel coronavirus SARS-CoV-2 is associated with a high rate of delirium resulting in encephalopathy, prominent agitation, and confusion . Considering neurotropism of coronaviruses, a direct central nervous system invasion resulting in encephalopathy of SARS-CoV2 is discussed [2, 3]. Recent data reported an enhancement in leptomeningeal spaces and bilateral frontotemporal hypoperfusion in SARS-CoV-2 . Since delirium however might also be caused by the systemic injury in critical illness , it remains debatable if the high rate of delirium is specifically associated with SARS-CoV-2 or rather a common complication of viral ARDS. We therefore compared delirium in ARDS patients caused by either SARS-CoV-2 or influenza A and B viruses.
We performed a single-center retrospective register analysis including invasive ventilated patients with ARDS and SARS-Cov-2 or influenza infection treated between 2015 and May 2020. We analyzed delirium by NuDesc (nursing delirium screening scale) score and RASS (Richmond agitation and sedation scale) score which are routinely assessed three times a day by especially trained nurses in all patients on our ICU. The NuDesc score is approved and shows a high sensitivity and specifity .
A total of 83 patients with ARDS were identified (44 and 39; with SARS-Cov-2 and influenza, respectively). Thirty-seven (22 and 15) died before extubation and 10 (2 and 8) were transferred with tracheotomia without the possibility of delirium evaluation using a verbal test. We therefore analyzed 36 (20 and 16) patients. Besides of age (patients with SARS-Cov-2 infection were significantly older), groups were homogenous (see Table 1).
Of all analyzed patients 69.4% (65.0 and 75.0% with SARS-CoV-2 and influenza, respectively) were diagnosed with delirium at any time during the ICU stay. Delirium duration tended to be longer in patients with SARS-CoV-2 (5.1 ± 4.3 days vs. 2.8 ± 2.4 days, p = 0.13). Delirium severity, defined as maximum of NuDesc score, also tended to be more distinctive in SARS-Cov-2 patients (NuDesc score at maximum: 5.2 ± 2.6 vs. 3.7 ± 1.8, p = 0.11). The onset of delirium after extubation was similar (0.50 ± 1.08 days vs. 0.8 ± 1.6 days). For the delirium presentation, see Fig. 1.
In this registry study of delirium in viral ARDS, we found no statistical significant difference in delirium prevalence, intensity, or type of delirium comparing patients with SARS-CoV-2 to those with influenza. We therefore hypothesize that delirium observed in COVID-19 patients has to be considered a complication of ARDS rather than SARS-CoV-2 specific. Considering the retrospective nature of data presented here, our results have to be considered hypothesis generating and have to be confirmed in a larger patient collective.
Availability of data and materials
The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.
Acute respiratory distress syndrome
Nursing delirium screening scale
Richmond agitation and sedation scale
Therapeutic Intervention Scoring System
Simplified Acute Physiology Score
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The article processing charge was funded by the Baden-Wuerttemberg Ministry of Science, Research and Art and University of Freiburg in the funding programme Open Access Publishing.
Ethics approval and consent to participate
This retrospective study was approved by the ethics committee of the Albert Ludwigs University of Freiburg, file number 387/19.
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The authors declare that they have no competing interests.
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Jäckel, M., Bemtgen, X., Wengenmayer, T. et al. Is delirium a specific complication of viral acute respiratory distress syndrome?. Crit Care 24, 401 (2020). https://doi.org/10.1186/s13054-020-03136-6
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