Delirium has been shown to occur in 14-56% of postoperative, hospitalized elderly persons, making it one of the most common postoperative complications for the older patient.
The aim of this study was to determine factors associated with recovery of delirium from postoperative day one (POD 1) to postoperative day two (POD 2). The hypothesis was that those with less pain are more likely to recover from delirium by POD 2.
Patients aged 65 or older who were scheduled for noncardiac surgery, spoke English, and who developed delirium on POD 1 as detected by the Confusion Assessment Method (CAM) were included. Total sample size was 176 patients. Postoperative delirium on day two was also measured with the CAM. Postoperative pain was assessed on POD 1 and 2 using the Numeric Rating Scale (NRS). Postoperative pain medications were abstracted from patient medical records.
One hundred seventy six patients developed delirium on POD 1 with 66 (38%) recovering from delirium by POD 2. The mean age of those patients who recovered from delirium was 72.5 ± 5.7 (N=66) while the mean age of those patients who did not recover from delirium was 75.9 ± 6.5 (N=110). Multivariate logistic regression revealed that patients less than age 75 were more likely to recover from delirium (OR=2.31; 95% CI=1.18-4.53; p=0.015) as were patients who had pain scores of less than 5 on day two (OR=2.59; 95% CI=1.26-5.35; p=0.0098).
Patients with lower pain levels (NRS 4 or less) were more likely to recover from delirium on POD 2. The type of postoperative pain therapy (the use or non-use of patient controlled analgesia) was not related to the recovery of delirium. The results suggest that aggressive pain management in the first 48 hours postoperatively may be important in promoting recovery from postoperative delirium.
Keywords: Postoperative delirium, pain management, geriatrics, research