Abstract
Background:
Preoperative cognitive impairment is a strong risk factor for the development of postoperative delirium in older patients. The cognitive screening of patients in low- and middle-income countries remains a challenge due to socio-economic and cultural differences.
Method:
This study was performed in 153 older patients undergoing lower limb orthopaedic surgery. Patients who were unable to speak and understand the Hindi language, patients with hearing (unaided) or speaking impairment, and patients with altered mental status were excluded. One day prior to the scheduled surgery, cognitive screening of patients using the animal fluency test and six-item screener was performed. Patients were screened daily for postoperative delirium using the confusion assessment method until 3 days after the surgery.
Results:
The incidence of postoperative delirium was 6% in our study population. We found that statistically significant difference between the patients who developed postoperative delirium and those who remained unaffected, in terms of frailty, animal fluency test score, and duration of surgery. Frailty and the duration of surgery independently affected postoperative delirium. The receiver operating characteristic curve of animal fluency test and six-item screener showed areas under the curve of 0.796 and 0.656, respectively. The best cut-off point of animal fluency test for prediction of postoperative delirium was less than 8.50 with a sensitivity of 77.8% and a specificity of 66%.
Conclusion:
The preoperative cognitive screening using animal fluency test can predict the occurrence of postoperative delirium with fair accuracy in older patients undergoing orthopaedic surgery. In contrast, the six-item screener demonstrated a weak association with postoperative delirium within our study population.
Keywords
Get full access to this article
View all access options for this article.