Delirium in COVID-19: can we make the unknowns knowns?

Frequency and burden of neurological manifestations upon hospital presentation in COVID-19 patients: Findings from a large Brazilian cohort

BACKGROUND

Scientific data regarding the prevalence of COVID-19 neurological manifestations and prognosis in Latin America countries is still lacking. Therefore, the study aims to understand neurological manifestations of SARS-CoV 2 infection and outcomes in the Brazilian population.

METHODS

This study is part of the Brazilian COVID-19 Registry, a multicentric cohort, including data from 37 hospitals. For the present analysis, patients were grouped according to the presence of reported symptoms (i.e., headache; anosmia and ageusia; syncope and dizziness) vs. clinically-diagnosed neurological manifestations (clinically-defined neurological syndrome: neurological signs or diagnoses captured by clinical evaluation) and matched with patients without neurological manifestations by age, sex, number of comorbidities, hospital of admission, and whether or not patients had underlying neurological disease.

RESULTS

From 6,635 hospitalized patients with COVID-19, 30.8% presented reported neurological manifestations, 10.3% were diagnosed with a neurological syndrome and 60.1% did not show any neurological manifestations. In patients with reported symptoms, the most common ones were headache (20.7%), ageusia (11.1%) and anosmia (8.0%). In patients with neurological syndromes, acute encephalopathy was the most common diagnosis (9.7%). In the matched analysis, patients with neurological syndromes presented more cases of septic shock (17.0 vs. 13.0%, p = 0.045), intensive care unit admission (45.3 vs. 38.9%, p = 0.023), and mortality (38.7 vs. 32.6%, p = 0.026; and 39.2 vs. 30.3%, p < 0.001) when compared to controls.

CONCLUSION

COVID-19 in-hospital patients with clinically defined neurological syndromes presented a higher incidence of septic shock, ICU admission and death when compared to controls.

Delirium in Adults With COVID-19-Related Acute Respiratory Distress Syndrome: Comparison With Other Etiologies

BACKGROUND AND OBJECTIVES

Neurologic complications have been associated with COVID-19, including delirium. Such complications have been reported to be frequent among intensive care unit (ICU)-admitted patients. We hypothesized that the rate of neurologic complications would be higher in COVID-19 associated acute respiratory distress syndrome (ARDS) than those who develop ARDS from a different cause.

METHODS

We conducted a retrospective cohort study in the adult ICU of Lausanne University Hospital, including all consecutive patients fulfilling the Berlin criteria for ARDS hospitalized between December 2017 and June 2021, stratifying exposure between COVID-19 or not. The primary outcome was delirium onset during ICU stay, defined by the confusion assessment method (CAM-ICU). Exploratory outcomes included development of neurologic complications of the central nervous system (stroke, hemorrhage, and vasculitis), critical illness weakness, and 30- and 180-day all-cause mortality.

RESULTS

Three hundred eleven patients were included in the study (253 with COVID-19 and 58 with other causes) and CAM-ICU could be assessed in 231 (74.3% in COVID-19 vs 74.1% in non-COVID-19). The proportion of patients developing delirium was similar in patients with COVID-19 and controls in univariate comparison (69.1% vs 60.5%, p = 0.246). Yet, patients with COVID-19 had a higher body mass index, lower ICU severity, longer mechanical ventilation, and higher sedation doses (propofol and dexmedetomidine). After adjusting for these factors in a multivariable analysis, the risk of delirium remained comparable across groups (adjusted OR [95% CI]: 0.86 [0.35-2.1]). Similarly, COVID-19-related ARDS had no effect on all-cause mortality at 30 days (adjusted OR: 0.87 [0.39-1.92]) and 180 days (adjusted OR: 0.67 [0.33-1.35]). Finally, neurologic complications affecting the CNS (adjusted OR: 1.15 [0.25-5.29]) and critical illness weakness (adjusted OR: 2.99 [0.97-9.1]) were not higher in the COVID-19 group.

DISCUSSION

Compared with other etiologies, patients with COVID-19 did not have higher incidence of delirium and other neurologic complications, after accounting for underlying disease severity in patients with ARDS. Management of COVID-19-associated ARDS needed longer invasive ventilation and higher sedation, which could explain higher rates of delirium in uncontrolled studies.

Sedative polypharmacy mediates the effect of mechanical ventilation on delirium in critically ill COVID-19 patients: A retrospective cohort study

BACKGROUND

Polypharmacy of sedatives (PP) is a potentially modifiable, iatrogenic risk factor for ICU delirium. The extent to which sedative PP influenced development of high rates of delirium among critically ill COVID-19 patients is unknown. We tested the hypothesis that PP, defined as the use of four or more classes of intravenous agents, is a mediator in the causal pathway of mechanical ventilation and delirium.

METHODS

Retrospective cohort study of adults admitted with a primary diagnosis of RT-PCR+ for SARS-CoV2 to ICUs of a tertiary-level academic medical center between February 2020 and April 2021. Mediation analysis was conducted with bootstrap estimation to assess whether an association between mechanical ventilation and delirium was mediated by PP. Analyses were adjusted for potential confounders related to mechanical ventilation, mediator, and outcome, including age, gender, vasopressor use, median RASS scores, SOFA score within 24 h of admission, and maximum CRP levels.

RESULTS

A total of 212 patients were included in the analysis. Of total patients, 72.6%(154/212) of patients had delirium (CAM-ICU+) during ICU stay. 54.7%(116/212) patients received PP. Mechanical ventilation (OR 3.81 [1.16-12.52]) and PP (OR 7.38 [2.4-22.68]) were identified as risk factors for development of ICU delirium after adjusting for prespecified confounders. PP acts as a mediator in the causal pathway between mechanical ventilation and delirium. 39% (95% CI: 17%-94%) of the effect of mechanical ventilation on delirium was mediated through PP.

CONCLUSION

PP mediates approximately 39% of the effect of mechanical ventilation on delirium, which is clinically and statistically significant. Studies should assess whether mitigating PP could lead to reduction in ICU delirium.

IMPLICATION STATEMENT

PP of sedatives (defined as use of four or more intravenous agents) mediates approximately 39% of the effect of mechanical ventilation on development of ICU delirium. Avoidance of sedative PP may represent a viable strategy for reduction of ICU delirium.

Prevalence and Risk Factor Analysis of Post-Intensive Care Syndrome in Patients with COVID-19 Requiring Mechanical Ventilation: A Multicenter Prospective Observational Study

Introduction: Post-intensive care syndrome (PICS) is an emerging problem in critically ill patients and the prevalence and risk factors are unclear in patients with severe coronavirus disease 2019 (COVID-19). This multicenter prospective observational study aimed to investigate the prevalence and risk factors of PICS in ventilated patients with COVID-19 after ICU discharge. Methods: Questionnaires were administered twice in surviving patients with COVID-19 who had required mechanical ventilation, concerning Barthel Index, Short-Memory Questionnaire, and Hospital Anxiety and Depression Scale scores. The risk factors for PICS were examined using a multivariate logistic regression analysis. Results: The first and second PICS surveys were obtained at 5.5 and 13.5 months (mean) after ICU discharge, with 251 and 209 patients completing the questionnaires and with a prevalence of PICS of 58.6% and 60.8%, respectively, along with the highest percentages of cognitive impairment. Delirium (with an odds ratio of (OR) 2.34, 95% CI 1.1–4.9, and p = 0.03) and the duration of mechanical ventilation (with an OR of 1.29, 95% CI 1.05–1.58, and p = 0.02) were independently identified as the risk factors for PICS in the first PICS survey. Conclusion: Approximately 60% of the ventilated patients with COVID-19 experienced persistent PICS, especially delirium, and required longer mechanical ventilation.

Electroencephalogram-Based Evaluation of Impaired Sedation in Patients with Moderate to Severe COVID-19 ARDS

The sedation management of patients with severe COVID-19 is challenging. Processed electroencephalography (pEEG) has already been used for sedation management before COVID-19 in critical care, but its applicability in COVID-19 has not yet been investigated. We performed this prospective observational study to evaluate whether the patient sedation index (PSI) obtained via pEEG may adequately reflect sedation in ventilated COVID-19 patients. Statistical analysis was performed by linear regression analysis with mixed effects. We included data from 49 consecutive patients. None of the patients received neuromuscular blocking agents by the time of the measurement. The mean value of the PSI was 20 (±23). The suppression rate was determined to be 14% (±24%). A deep sedation equivalent to the Richmond Agitation and Sedation Scale of −3 to −4 (correlation expected PSI 25−50) in bedside examination was noted in 79.4% of the recordings. Linear regression analysis revealed a significant correlation between the sedative dosages of propofol, midazolam, clonidine, and sufentanil (p < 0.01) and the sedation index. Our results showed a distinct discrepancy between the RASS and the determined PSI. However, it remains unclear to what extent any discrepancy is due to the electrophysiological effects of neuroinflammation in terms of pEEG alteration, to the misinterpretation of spinal or vegetative reflexes during bedside evaluation, or to other causes.

Delirium in Critically Ill Patients with and without COVID-19-A Retrospective Analysis

BACKGROUND

Delirium complicating the course of Intensive care unit (ICU) therapy is a known driver of morbidity and mortality. It has been speculated that infection with the neurotrophic SARS-CoV-2 might promote delirium.

METHODS

Retrospective registry analysis including all patients treated at least 48 h on a medical intensive care unit. The primary endpoint was development of delirium as diagnosed by Nursing Delirium screening scale ≥2. Results were confirmed by propensity score matching.

RESULTS

542 patients were included. The primary endpoint was reached in 352/542 (64.9%) patients, without significant differences between COVID-19 patients and non-COVID-19 patients (51.4% and 65.9%, respectively, p = 0.07) and correlated with prolonged ICU stay in both groups. In a subgroup of patients with ICU stay >10 days delirium was significantly lower in COVID-19 patients (p ≤ 0.01). After adjustment for confounders, COVID-19 correlated independently with less ICU delirium (p ≤ 0.01). In the propensity score matched cohort, patients with COVID-19 had significantly lower delirium incidence compared to the matched control patients (p ≤ 0.01).

CONCLUSION

Delirium is frequent in critically ill patients with and without COVID-19 treated at an intensive care unit. Data suggests that COVID-19 itself is not a driver of delirium per se.