Patients with ARDS, preexisting psychiatric illness more likely to develop ICU delirium
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Patients with acute respiratory distress syndrome and a preexisting psychiatric illness — in particular, generalized anxiety disorder — are more likely to develop delirium while in the ICU compared with those without a preexisting illness.
In a study of 150 patients with ARDS, 38.7% were diagnosed with ICU delirium. Forty-eight percent of those with preexisting psychiatric illnesses had ICU delirium compared with 32.6% of those without a preexisting illness (OR = 1.93; 95% CI, 0.98-3.79; P = .055), according to data presented at the virtual CHEST Annual Meeting.
When the researchers analyzed individual psychiatric illnesses, generalized anxiety disorder, in particular, was associated with development of ICU delirium (OR = 3; 95% CI, 1.32-6.83; P = .007).
Anxiety medications before admission were used by 22% of patients with ARDS and ICU delirium compared with 7.6% of patients without delirium (OR = 3.59; 95% CI, 1.34-9.64; P = .008).
“A possible explanation for the higher rate of delirium in patients with preexisting psychiatric illnesses could be the need to use higher doses of benzodiazepines. The increase is required to achieve adequate sedation, putting them at a higher risk of withdrawal symptoms. In addition, home psychotropic medications are often withheld in the ventilated patients. They are often receiving other sedatives that potentially predisposes them to withdrawal symptoms, which often manifests as delirium,” Saminder Kalra, MD, with the department of pulmonary and critical care medicine at University of Florida, Gainesville, said in a press release.
The retrospective study enrolled patients with ARDS aged 18 years and older who were admitted to the ICU from 2016 to 2018. All patients received mechanical ventilation support for more than 48 hours. For this study, psychiatric illnesses were defined as the presence of a major depressive disorder, generalized anxiety disorder, bipolar disorder, schizophrenia or PTSD before admission.
This study adds to the current knowledge base. Although previous studies associated a higher incidence of psychiatric illnesses arising among ARDS survivors, little is known about the impact of preexisting psychiatric illness on the hospital course of patients with ARDS.
“Patients with ARDS with preexisting psychiatric illness may be more prone to the development of ICU delirium, and further studies are needed to evaluate ways to mitigate risk factors in this population,” the researchers concluded.