More than half of a cohort of elderly patients with obstructive sleep
apnea developed postoperative delirium after knee surgery, according to recent
Researchers from several sites in the United States aimed to explore
effective treatment strategies for postoperative delirium in the elderly. The
causative factors of this common complication may be multiple and varied and
may be linked to increased morbidity and mortality, and subsequent cognitive
Eligible participants in the prospective study were aged 65 years or
older and were undergoing elective knee arthroplasty. They were assessed on
days 2 and 3 post-surgery to determine whether they met criteria for Diagnostic
and Statistical Manual of Mental Disorders-IV delirium.
Dementia, mini-mental state exam scores less than 24, delirium,
clinically significant central nervous system/neurologic disorder, current
alcoholism, or any serious psychiatric disorder comprised the exclusion
Using data from medical charts and polysomnography records,
investigators evaluated patients for pre-existing medical conditions and for
the occurrence of obstructive sleep apnea.
The final analysis included 106 patients. Twenty-five percent of those
patients developed postoperative delirium.
There were 15 patients with obstructive sleep apnea. While postoperative
delirium occurred in 53% of those patients, it occurred in just 20% of the
patients without obstructive sleep apnea (P=.0123; OR=4.3).
Multivariate analysis results indicated that obstructive sleep apnea was
the only statistically significant predictor of postsurgery delirium.