Delirium is a serious and often temporary disturbance in mental functions that can occur as a result of a medical condition, such as an infection, an injury, or substance abuse. It is characterized by confusion, disorientation, and changes in perception, attention, and behavior. Delirium can be a sign of an underlying condition and requires prompt medical attention. It can also have significant consequences, including prolonged hospital stays and long-term cognitive impairment.
Drug classes commonly used to regulate blood pressure are not effective in preventing delirium acquired in the ICU.
According to a recent study conducted by a team of researchers from the Regenstrief Institute and the universities of South Carolina and Indiana, the most widely used blood pressure medications, when taken for a minimum of six months before being admitted to an intensive care unit (ICU), did not provide protection against delirium in the ICU. The findings of the study were not influenced by the patient’s age, gender, race, pre-existing health conditions, or insurance coverage.
Each year, approximately seven million hospitalized patients in the U.S. are impacted by delirium, an acute failure of the brain. This condition is linked to prolonged hospital stays and ICU stays, increased use of mechanical ventilation, long-lasting cognitive problems, the need for placement in a nursing home, and a higher risk of death. The more severe and longer-lasting the delirium, the worse the post-discharge cognitive and functional outcomes are likely to be.
“We have been looking at potential ways to decrease delirium severity and duration. In this study, we looked at ACE inhibitors and angiotensin receptor blockers because these drugs stabilize blood pressure and are thought to have neuroprotective qualities. We wanted to learn whether chronic exposure to these drugs may be important in preventing delirium,” said study senior author Babar Khan, M.D., M.S., a Regenstrief Institute and Indiana University School of Medicine researcher-clinician. “Unfortunately, we did not find a lower prevalence of delirium among patients prescribed these medications prior to ICU admission, compared to patients who had not taken them.”
Chronic high blood pressure, which can be successfully lowered by ACE inhibitors and angiotensin receptor blockers, is one of the risk factors for ICU-acquired delirium.
The observational study of the electronic health records of 4,791 racially diverse patients showed that taking these blood pressure medications for at least six months prior to admission to an ICU did not provide enough protective benefit or generate enough brain resilience to prevent delirium.
In another work that looked at a pharmacological approach to delirium, Dr. Khan was a co-author of a study published in the New England Journal of Medicine in 2018 which found that commonly prescribed antipsychotic drugs did not alter the duration of delirium.
In the continued quest to identify therapies to prevent or manage delirium, he and fellow Regenstrief Institute and IU School of Medicine faculty member Sikandar Khan, D.O., M.S., are currently collaborating with the Mayo Clinic on a multi-site study to determine if a specially designed music intervention can reduce the likelihood of mechanically ventilated older adult ICU patients developing delirium and can also improve post-ICU brain health.
“This study of blood pressure medications represents our ongoing efforts to understand the role of vascular risk factors in delirium. Our long-term goal is to understand how different biological processes in aging, such as blood pressure, inflammation, etc., interact, eventually leading to delirium and then ultimately dementia”, said Dr. Sikandar Khan.
Reference: “Relationship between angiotensin-converting enzyme inhibitors and angiotensin receptor blockers prescribing and delirium in the ICU-A secondary analysis” by Malissa A. Mulkey Ph.D., APRN, CCNS, CCRN, CNRN, Sikandar Khan DO, MS, Anthony Perkins MS, Sujuan Gao Ph.D., Sophia Wang MD, Noll Campbell PharmD, MS and Babar Khan MD, MS, 11 March 2023, Journal of the American Geriatrics Society.
DOI: 10.1111/jgs.18285
The study was funded by the National Institutes of Health’s National Institute of Nursing Research and National Institute on Aging.
