Delirium Incidence, Duration, and Severity in Critically Ill Patients With Coronavirus Disease 2019

Abstract

Objectives: To determine delirium occurrence rate, duration, and severity in patients admitted to the ICU with coronavirus disease 2019.

Design: Retrospective data extraction study from March 1, 2020, to June 7, 2020. Delirium outcomes were assessed for up to the first 14 days in ICU.

Setting: Two large, academic centers serving the state of Indiana.

Patients: Consecutive patients admitted to the ICU with positive severe acute respiratory syndrome coronavirus 2 nasopharyngeal swab polymerase chain reaction test from March 1, 2020, to June 7, 2020, were included. Individuals younger than 18 years of age, without any delirium assessments, or without discharge disposition were excluded.

Measurements and main results: Primary outcomes were delirium rates and duration, and the secondary outcome was delirium severity. Two-hundred sixty-eight consecutive patients were included in the analysis with a mean age of 58.4 years (sd, 15.6 yr), 40.3% were female, 44.4% African American, 20.7% Hispanic, and a median Acute Physiology and Chronic Health Evaluation II score of 18 (interquartile range, 13-25). Delirium without coma occurred in 29.1% of patients, delirium prior to coma in 27.9%, and delirium after coma in 23.1%. The first Confusion Assessment Method for the ICU assessment was positive for delirium in 61.9%. Hypoactive delirium was the most common subtype (87.4%). By day 14, the median number of delirium/coma-free were 5 days (interquartile range, 4-11 d), and median Confusion Assessment Method for the ICU-7 score was 6.5 (interquartile range, 5-7) indicating severe delirium. Benzodiazepines were ordered for 78.4% of patients in the cohort. Mechanical ventilation was associated with greater odds of developing delirium (odds ratio, 5.0; 95% CI, 1.1-22.2; p = 0.033) even after adjusting for sedative medications. There were no between-group differences in mortality.

Conclusions: Delirium without coma occurred in 29.1% of patients admitted to the ICU. Delirium persisted for a median of 5 days and was severe. Mechanical ventilation was significantly associated with odds of delirium even after adjustment for sedatives. Clinical attention to manage delirium duration and severity, and deeper understanding of the virus' neurologic effects is needed for patients with coronavirus disease 2019.

Keywords: brain diseases; coma; coronavirus disease 2019; critical illness; delirium; respiratory insufficiency.

Figure 1.

Daily rates of delirium, coma, or without delirium/coma status as assessed up to first 14 d of ICU stay (n = 268). Number above each bar column indicates number of patients assessed per day. Daily percentages do not equal 100% due to incomplete assessments, death, or discharge from ICU. Delirium was defined as a positive Confusion Assessment Method for the ICU (CAM-ICU) assessment on either morning or afternoon assessment. Coma was defined by Richmond Agitation-Sedation Scale (RASS) score of –4 or –5. Without delirium or coma was defined by RASS greater than –4 and a negative CAM-ICU on either morning or afternoon assessment.

Figure 2.

Subtypes of delirium in critically ill patients with coronavirus disease 2019 (n = 268). Number above each bar column indicates number of patients assessed for delirium per day. Daily percentages do not equal 100% due to incomplete assessments, death, discharge from ICU, or screening negative for delirium. Number of patients screening positive for delirium per day: 65 (day 1), 92 (day 2), 87 (day 3), 98 (day 4), 93 (day 5), 93 (day 6), 99 (day 7), 95 (day 8), 87 (day 9), 75 (day 10), 81 (day 11), 72 (day 12), 61 (day 13), and 63 (day 14). Confusion Assessment Method for the ICU (CAM-ICU) and Richmond Agitation-Sedation Scale (RASS) assessments were performed up to bid while patient was admitted to the ICU. Hypoactive delirium was defined by RASS of –1 to –3 with positive CAM-ICU and hyperactive delirium was defined by a RASS score of +1 to +3 with positive CAM-ICU. Mixed delirium was defined as patients with both hyperactive and hypoactive delirium assessment on a given ICU day.