Key Point:

• Cognitive impairment is common among elderly ICU patients, yet it is frequently overlooked by the medical staff.

NEW HAVEN, CONN—Amid all the machines of the modern ICU, a simple observation is often overlooked: Many critically ill elderly patients have preexisting cognitive impairment. Yet half or more of the time, ICU physicians are unaware of the patients’ cognitive limitations.

In a recent study, 63 (38%) of 165 elderly ICU patients were found to have preexisting cognitive deficits.[1] Lead study author Margaret A. Pisani, MD, said that this rate is not surprising. “Cognitive impairment is frequently present (and also often unrecognized) among elderly patients in physicians’ offices and other non-ICU settings,” explained Dr. Pisani, an Assistant Professor of Medicine at the Yale University School of Medicine.

What is surprising and of great concern, she added, is that the ICU’s attending physicians, all of whom were board certified, were unaware of 53% of the cases of preexisting cognitive impairment. The unit’s interns were unaware of 59% of the cases.

“It is important to be aware of a patient’s baseline status because we often give psychoactive medications that may further impair cognition,” stressed Dr. Pisani. “We also frequently ask patients to make decisions that they may not be able to make if they are cognitively impaired.”

All of the patients in the study were intubated and thus limited in their ability to respond to questioning. Consequently, Dr. Pisani and her colleagues relied primarily on proxies—usually a family member and/or nurse—for information on the patients’ cognitive status. Patients who did not have a suitable proxy were ineligible for the study.

To minimize reporting and recall bias, proxy interviews were completed within 48 hours of patient admission to the ICU. During the same period, the attending physicians and interns were asked eight questions about the patients’ comorbidities at admission. The question about cognitive impairment was embedded within queries about other comorbidities to avoid making it obvious and thereby skewing the study’s results.

The attending physicians reported cognitive deficits in 36 of the 165 patients. However, in seven cases, this information was inaccurate. The interns reported the presence of cognitive limitations in a higher number of patients (41), but their error rate was also higher; they falsely attributed cognitive impairment to 15 patients with normal mentation. Both physician groups were better at identifying patients with severe cognitive deficits than those with mild limitations; however, they identified only slightly more than half of the cases of severe impairment.

Among the 63 patients with preexisting cognitive deficits, risk factors for impairment included advanced age, female sex, ICU admission from a nursing home, and higher baseline APACHE II score. The medical staff was best able to identify cognitive limitations when patients had been admitted from a nursing home and had impairments in activities of daily living.

—Timothy Begany

Reference
1. Pisani MA, Redlich C, McNicoll L, et al. Underrecognition of preexisting cognitive impairment by physicians in older ICU patients. Chest. 2003;124:2267-2274.

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